Analysis of Simulated Temporal Illumination at the Lunar PSRs

NASA Astrophysics Data System (ADS)

Thompson, T. J.; Mahanti, P.

2018-04-01

Illumination on the Moon is modeled temporally for permanently shadowed regions to lighting trends. Crater topography is used to generate viewfactor maps, which show which areas contribute most to scattered light into the primary shadows.

Sources and preparation of data for assessing trends in concentrations of pesticides in streams of the United States, 1992–2010

USGS Publications Warehouse

Martin, Jeffrey D.; Eberle, Michael; Nakagaki, Naomi

2011-01-01

This report updates a previously published water-quality dataset of 44 commonly used pesticides and 8 pesticide degradates suitable for a national assessment of trends in pesticide concentrations in streams of the United States. Water-quality samples collected from January 1992 through September 2010 at stream-water sites of the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program and the National Stream Quality Accounting Network (NASQAN) were compiled, reviewed, selected, and prepared for trend analysis. The principal steps in data review for trend analysis were to (1) identify analytical schedule, (2) verify sample-level coding, (3) exclude inappropriate samples or results, (4) review pesticide detections per sample, (5) review high pesticide concentrations, and (6) review the spatial and temporal extent of NAWQA pesticide data and selection of analytical methods for trend analysis. The principal steps in data preparation for trend analysis were to (1) select stream-water sites for trend analysis, (2) round concentrations to a consistent level of precision for the concentration range, (3) identify routine reporting levels used to report nondetections unaffected by matrix interference, (4) reassign the concentration value for routine nondetections to the maximum value of the long-term method detection level (maxLT-MDL), (5) adjust concentrations to compensate for temporal changes in bias of recovery of the gas chromatography/mass spectrometry (GCMS) analytical method, and (6) identify samples considered inappropriate for trend analysis. Samples analyzed at the USGS National Water Quality Laboratory (NWQL) by the GCMS analytical method were the most extensive in time and space and, consequently, were selected for trend analysis. Stream-water sites with 3 or more water years of data with six or more samples per year were selected for pesticide trend analysis. The selection criteria described in the report produced a dataset of 21,988 pesticide samples at 212 stream-water sites. Only 21,144 pesticide samples, however, are considered appropriate for trend analysis.

The trend of the multi-scale temporal variability of precipitation in Colorado River Basin

NASA Astrophysics Data System (ADS)

Jiang, P.; Yu, Z.

2011-12-01

Hydrological problems like estimation of flood and drought frequencies under future climate change are not well addressed as a result of the disability of current climate models to provide reliable prediction (especially for precipitation) shorter than 1 month. In order to assess the possible impacts that multi-scale temporal distribution of precipitation may have on the hydrological processes in Colorado River Basin (CRB), a comparative analysis of multi-scale temporal variability of precipitation as well as the trend of extreme precipitation is conducted in four regions controlled by different climate systems. Multi-scale precipitation variability including within-storm patterns and intra-annual, inter-annual and decadal variabilities will be analyzed to explore the possible trends of storm durations, inter-storm periods, average storm precipitation intensities and extremes under both long-term natural climate variability and human-induced warming. Further more, we will examine the ability of current climate models to simulate the multi-scale temporal variability and extremes of precipitation. On the basis of these analyses, a statistical downscaling method will be developed to disaggregate the future precipitation scenarios which will provide a more reliable and finer temporal scale precipitation time series for hydrological modeling. Analysis results and downscaling results will be presented.

Spatial and Temporal Dust Source Variability in Northern China Identified Using Advanced Remote Sensing Analysis

NASA Technical Reports Server (NTRS)

Taramelli, A.; Pasqui, M.; Barbour, J.; Kirschbaum, D.; Bottai, L.; Busillo, C.; Calastrini, F.; Guarnieri, F.; Small, C.

2013-01-01

The aim of this research is to provide a detailed characterization of spatial patterns and temporal trends in the regional and local dust source areas within the desert of the Alashan Prefecture (Inner Mongolia, China). This problem was approached through multi-scale remote sensing analysis of vegetation changes. The primary requirements for this regional analysis are high spatial and spectral resolution data, accurate spectral calibration and good temporal resolution with a suitable temporal baseline. Landsat analysis and field validation along with the low spatial resolution classifications from MODIS and AVHRR are combined to provide a reliable characterization of the different potential dust-producing sources. The representation of intra-annual and inter-annual Normalized Difference Vegetation Index (NDVI) trend to assess land cover discrimination for mapping potential dust source using MODIS and AVHRR at larger scale is enhanced by Landsat Spectral Mixing Analysis (SMA). The combined methodology is to determine the extent to which Landsat can distinguish important soils types in order to better understand how soil reflectance behaves at seasonal and inter-annual timescales. As a final result mapping soil surface properties using SMA is representative of responses of different land and soil cover previously identified by NDVI trend. The results could be used in dust emission models even if they are not reflecting aggregate formation, soil stability or particle coatings showing to be critical for accurately represent dust source over different regional and local emitting areas.

Temporal trends in BMI in Argentina by socio-economic position and province-level economic development, 2005-2009.

PubMed

Christine, Paul J; Diez Roux, Ana V; Wing, Jeffrey J; Alazraqui, Marcio; Spinelli, Hugo

2015-04-01

We investigated temporal trends in BMI, and assessed hypothesized predictors of trends including socio-economic position (SEP) and province-level economic development, in Argentina. Using multivariable linear regression, we evaluated cross-sectional patterning and temporal trends in BMI and examined heterogeneity in these associations by SEP and province-level economic development with nationally representative samples from Argentina in 2005 and 2009. We calculated mean annual changes in BMI for men and women to assess secular trends. Women, but not men, exhibited a strong cross-sectional inverse association between SEP and BMI, with the lowest-SEP women having an average BMI 2.55 kg/m(2) greater than the highest-SEP women. Analysis of trends revealed a mean annual increase in BMI of 0.19 kg/m(2) and 0.15 kg/m(2) for women and men, respectively, with slightly greater increases occurring in provinces with greater economic growth. No significant heterogeneity in trends existed by individual SEP. BMI is increasing rapidly over time in Argentina irrespective of various sociodemographic characteristics. Higher BMI remains more common in women of lower SEP compared with those of higher SEP.

Geographical, temporal and racial disparities in late-stage prostate cancer incidence across Florida: A multiscale joinpoint regression analysis

PubMed Central

2011-01-01

Background Although prostate cancer-related incidence and mortality have declined recently, striking racial/ethnic differences persist in the United States. Visualizing and modelling temporal trends of prostate cancer late-stage incidence, and how they vary according to geographic locations and race, should help explaining such disparities. Joinpoint regression is increasingly used to identify the timing and extent of changes in time series of health outcomes. Yet, most analyses of temporal trends are aspatial and conducted at the national level or for a single cancer registry. Methods Time series (1981-2007) of annual proportions of prostate cancer late-stage cases were analyzed for non-Hispanic Whites and non-Hispanic Blacks in each county of Florida. Noise in the data was first filtered by binomial kriging and results were modelled using joinpoint regression. A similar analysis was also conducted at the state level and for groups of metropolitan and non-metropolitan counties. Significant racial differences were detected using tests of parallelism and coincidence of time trends. A new disparity statistic was introduced to measure spatial and temporal changes in the frequency of racial disparities. Results State-level percentage of late-stage diagnosis decreased 50% since 1981; a decline that accelerated in the 90's when Prostate Specific Antigen (PSA) screening was introduced. Analysis at the metropolitan and non-metropolitan levels revealed that the frequency of late-stage diagnosis increased recently in urban areas, and this trend was significant for white males. The annual rate of decrease in late-stage diagnosis and the onset years for significant declines varied greatly among counties and racial groups. Most counties with non-significant average annual percent change (AAPC) were located in the Florida Panhandle for white males, whereas they clustered in South-eastern Florida for black males. The new disparity statistic indicated that the spatial extent of racial disparities reached a peak in 1990 because of an early decline in frequency of late-stage diagnosis observed for black males. Conclusions Analyzing temporal trends in cancer incidence and mortality rates outside a spatial framework is unsatisfactory, since it leads one to overlook significant geographical variation which can potentially generate new insights about the impact of various interventions. Differences observed among nested geographies in Florida show how the modifiable areal unit problem (MAUP) also impacts the analysis of temporal changes. PMID:22142274

Geographical, temporal and racial disparities in late-stage prostate cancer incidence across Florida: a multiscale joinpoint regression analysis.

PubMed

Goovaerts, Pierre; Xiao, Hong

2011-12-05

Although prostate cancer-related incidence and mortality have declined recently, striking racial/ethnic differences persist in the United States. Visualizing and modelling temporal trends of prostate cancer late-stage incidence, and how they vary according to geographic locations and race, should help explaining such disparities. Joinpoint regression is increasingly used to identify the timing and extent of changes in time series of health outcomes. Yet, most analyses of temporal trends are aspatial and conducted at the national level or for a single cancer registry. Time series (1981-2007) of annual proportions of prostate cancer late-stage cases were analyzed for non-Hispanic Whites and non-Hispanic Blacks in each county of Florida. Noise in the data was first filtered by binomial kriging and results were modelled using joinpoint regression. A similar analysis was also conducted at the state level and for groups of metropolitan and non-metropolitan counties. Significant racial differences were detected using tests of parallelism and coincidence of time trends. A new disparity statistic was introduced to measure spatial and temporal changes in the frequency of racial disparities. State-level percentage of late-stage diagnosis decreased 50% since 1981; a decline that accelerated in the 90's when Prostate Specific Antigen (PSA) screening was introduced. Analysis at the metropolitan and non-metropolitan levels revealed that the frequency of late-stage diagnosis increased recently in urban areas, and this trend was significant for white males. The annual rate of decrease in late-stage diagnosis and the onset years for significant declines varied greatly among counties and racial groups. Most counties with non-significant average annual percent change (AAPC) were located in the Florida Panhandle for white males, whereas they clustered in South-eastern Florida for black males. The new disparity statistic indicated that the spatial extent of racial disparities reached a peak in 1990 because of an early decline in frequency of late-stage diagnosis observed for black males. Analyzing temporal trends in cancer incidence and mortality rates outside a spatial framework is unsatisfactory, since it leads one to overlook significant geographical variation which can potentially generate new insights about the impact of various interventions. Differences observed among nested geographies in Florida show how the modifiable areal unit problem (MAUP) also impacts the analysis of temporal changes.

Spatial heterogeneity in statistical power to detect changes in lake area in Alaskan National Wildlife Refuges

USGS Publications Warehouse

Nicol, Samuel; Roach, Jennifer K.; Griffith, Brad

2013-01-01

Over the past 50 years, the number and size of high-latitude lakes have decreased throughout many regions; however, individual lake trends have been variable in direction and magnitude. This spatial heterogeneity in lake change makes statistical detection of temporal trends challenging, particularly in small analysis areas where weak trends are difficult to separate from inter- and intra-annual variability. Factors affecting trend detection include inherent variability, trend magnitude, and sample size. In this paper, we investigated how the statistical power to detect average linear trends in lake size of 0.5, 1.0 and 2.0 %/year was affected by the size of the analysis area and the number of years of monitoring in National Wildlife Refuges in Alaska. We estimated power for large (930–4,560 sq km) study areas within refuges and for 2.6, 12.9, and 25.9 sq km cells nested within study areas over temporal extents of 4–50 years. We found that: (1) trends in study areas could be detected within 5–15 years, (2) trends smaller than 2.0 %/year would take >50 years to detect in cells within study areas, and (3) there was substantial spatial variation in the time required to detect change among cells. Power was particularly low in the smallest cells which typically had the fewest lakes. Because small but ecologically meaningful trends may take decades to detect, early establishment of long-term monitoring will enhance power to detect change. Our results have broad applicability and our method is useful for any study involving change detection among variable spatial and temporal extents.

Depth-time interpolation of feature trends extracted from mobile microelectrode data with kernel functions.

PubMed

Wong, Stephen; Hargreaves, Eric L; Baltuch, Gordon H; Jaggi, Jurg L; Danish, Shabbar F

2012-01-01

Microelectrode recording (MER) is necessary for precision localization of target structures such as the subthalamic nucleus during deep brain stimulation (DBS) surgery. Attempts to automate this process have produced quantitative temporal trends (feature activity vs. time) extracted from mobile MER data. Our goal was to evaluate computational methods of generating spatial profiles (feature activity vs. depth) from temporal trends that would decouple automated MER localization from the clinical procedure and enhance functional localization in DBS surgery. We evaluated two methods of interpolation (standard vs. kernel) that generated spatial profiles from temporal trends. We compared interpolated spatial profiles to true spatial profiles that were calculated with depth windows, using correlation coefficient analysis. Excellent approximation of true spatial profiles is achieved by interpolation. Kernel-interpolated spatial profiles produced superior correlation coefficient values at optimal kernel widths (r = 0.932-0.940) compared to standard interpolation (r = 0.891). The choice of kernel function and kernel width resulted in trade-offs in smoothing and resolution. Interpolation of feature activity to create spatial profiles from temporal trends is accurate and can standardize and facilitate MER functional localization of subcortical structures. The methods are computationally efficient, enhancing localization without imposing additional constraints on the MER clinical procedure during DBS surgery. Copyright © 2012 S. Karger AG, Basel.

Spatial and temporal drivers of wildfire occurrence in the context of rural development in northern Wisconsin, USA

Treesearch

Brian R Miranda; Brian R Sturtevant; Susan I Stewart; Roger B. Hammer

2012-01-01

Most drivers underlying wildfire are dynamic, but at different spatial and temporal scales. We quantified temporal and spatial trends in wildfire patterns over two spatial extents in northern Wisconsin to identify drivers and their change through time. We used spatial point pattern analysis to quantify the spatial pattern of wildfire occurrences, and linear regression...

Tree invasion of a montane meadow complex: temporal trends, spatial patterns, and biotic interactions

Treesearch

Charles B. Halpern; Joseph A. Antos; Janine M. Rice; Ryan D. Haugo; Nicole L. Lang

2010-01-01

We combined spatial point pattern analysis, population age structures, and a time-series of stem maps to quantify spatial and temporal patterns of conifer invasion over a 200-yr period in three plots totaling 4 ha. In combination, spatial and temporal patterns of establishment suggest an invasion process shaped by biotic interactions, with facilitation promoting...

Analysis of temporal and spatial trends of hydro-climatic variables in the Wei River Basin.

PubMed

Zhao, Jing; Huang, Qiang; Chang, Jianxia; Liu, Dengfeng; Huang, Shengzhi; Shi, Xiaoyu

2015-05-01

The Wei River is the largest tributary of the Yellow River in China. The relationship between runoff and precipitation in the Wei River Basin has been changed due to the changing climate and increasingly intensified human activities. In this paper, we determine abrupt changes in hydro-climatic variables and identify the main driving factors for the changes in the Wei River Basin. The nature of the changes is analysed based on data collected at twenty-one weather stations and five hydrological stations in the period of 1960-2010. The sequential Mann-Kendall test analysis is used to capture temporal trends and abrupt changes in the five sub-catchments of the Wei River Basin. A non-parametric trend test at the basin scale for annual data shows a decreasing trend of precipitation and runoff over the past fifty-one years. The temperature exhibits an increase trend in the entire period. The potential evaporation was calculated based on the Penman-Monteith equation, presenting an increasing trend of evaporation since 1990. The stations with a significant decreasing trend in annual runoff mainly are located in the west of the Wei River primarily interfered by human activities. Regression analysis indicates that human activity was possibly the main cause of the decline of runoff after 1970. Copyright © 2015. Published by Elsevier Inc.

Temporal trends in physical violence, gender differences and spatial vulnerability of the location of victim's residences.

PubMed

Cavalcante, Gigliana Maria Sobral; de Macedo Bernardino, Ítalo; da Nóbrega, Lorena Marques; Ferreira, Raquel Conceição; Ferreira E Ferreira, Efigênia; d'Avila, Sérgio

2018-06-01

The aim of study was to describe trends in physical violence among Brazilian victims and investigate spatial vulnerability of the location of victim's residences. This study performed an ecological-level longitudinal analysis, examining violence rates over 4 years. Cases of 4795 victims of physical aggression attended at a Center of Legal Medicine were investigated. Trend analysis was used to evaluate the data, with the creation of polynomial regression models (p < 0.05). Violence rates showed significant temporal variations according to sociodemographic characteristics of victims (p < 0.05) and the circumstances of aggressions (p < 0.05). Moreover, there was a significant increase in violence rate in the North (R 2  = 16.1%; p = 0.019) and South (R 2  = 18.4%; p = 0.010), whereas the rural zone (R 2  = 10.1%; p = 0.028) presented a decrease. The findings highlight the need for protection policies that address spatial-temporal aspects. Copyright © 2018 Elsevier Ltd. All rights reserved.

Hot spots, hot moments and time-span of changes in drivers and their responses on carbon cycling in Europe

NASA Astrophysics Data System (ADS)

Tomelleri, E.; Forkel, M.; Fuchs, R.; Jung, M.; Mahecha, M. D.; Reichstein, M.; Weber, U.

2012-12-01

The objective of this study is to provide a complete quantitative assessment of the annual to decadal variability, hotspots of changes and the temporal magnitude of regional trends and variability for the main drivers of carbon cycle like climate and land use and their responses for Europe. For this purpose we used an harmonized climatic data set (ERA Interim and WATCH) and an historical land-use change reconstruction (HILDAv1, Fuchs in prep.). Both the data sets cover the period 1900-2010 and have a 0.25 deg spatial resolution. As driver response we used two different empirically up-scaled GPP fields: the first (MTE) obtained by the application of model trees (Jung et al. 2009) and a second (LUE) based on a light use efficiency model (Tomelleri in prep.). Both the approaches are based on the up-scaling of Fluxnet observations. The response fields have monthly temporal resolution and are limited to the period 1982-2011. We estimated break-points in time series of driver and response variables based on the method of Bai and Perron (2003) to identify changes in trends. This method was implemented in Verbesselt et al. 2010 and applied by deJong et al. 2011 to detect phenological and abrupt changes and trends in vegetation activity based on satellite-derived vegetation index time series. The analysis of drivers and responses allowed to identify the dominant factors driving the biosphere-atmosphere carbon exchange. The synchronous analysis of climatic drivers and land use change allowed us to explain most of the temporal and spatial variability showing that in the regions and time period where the most land use change occurred the climatic drivers are not sufficient to explain trends and oscillation in carbon cycling. The comparison of our analysis for the up-scaling methods shows some agreement: we found inconsistency in the spatial and temporal patterns in regions where the Fluxnet network is less dense. This can be explained by the conceptual difference in the up-scaling methods: while one is on pixel basis (MTE) the other (LUE) is up-scaling model parameters by bioclimatic regions. Our study shows the value of up-scaling methods for understanding the spatial-temporal variability of carbon cycling and how these are a valuable tool for spatial and temporal analysis. Furthermore, the use of climatic drivers and land-use change demonstrated the need of taking natural and anthropogenic drivers into consideration for explaining trends and oscillations. Possibly a further analysis including detailed management practices for forestry and agriculture would help in explaining the remaining variance. References: Bai, J., Perron, P.: Computation and analysis of multiple structural change models. Journal of Applied Econometrics, 18(1), 2003. Jung, M., Reichstein, M., and Bondeau, A.: Towards global empirical upscaling of FLUXNET eddy covariance observations: validation of a model tree ensemble approach using a biosphere model. Biogeosciences, 6, 2009. Verbesselt, J., Hyndman, R., Newnham, G., Culvenor, D.: Detecting trend and seasonal changes in satellite image time series. Remote Sensing of Environment,114(1), 2010. de Jong, R., Verbesselt, J., Schaepman, M.E., Bruin, S.: Trend changes in global greening and browning: contribution of short-term trends to longer-term change. Global Change Biology, 18, 2011.

A Proof of Concept Study of Function-Based Statistical Analysis of fNIRS Data: Syntax Comprehension in Children with Specific Language Impairment Compared to Typically-Developing Controls.

PubMed

Fu, Guifang; Wan, Nicholas J A; Baker, Joseph M; Montgomery, James W; Evans, Julia L; Gillam, Ronald B

2016-01-01

Functional near infrared spectroscopy (fNIRS) is a neuroimaging technology that enables investigators to indirectly monitor brain activity in vivo through relative changes in the concentration of oxygenated and deoxygenated hemoglobin. One of the key features of fNIRS is its superior temporal resolution, with dense measurements over very short periods of time (100 ms increments). Unfortunately, most statistical analysis approaches in the existing literature have not fully utilized the high temporal resolution of fNIRS. For example, many analysis procedures are based on linearity assumptions that only extract partial information, thereby neglecting the overall dynamic trends in fNIRS trajectories. The main goal of this article is to assess the ability of a functional data analysis (FDA) approach for detecting significant differences in hemodynamic responses recorded by fNIRS. Children with and without SLI wore two, 3 × 5 fNIRS caps situated over the bilateral parasylvian areas as they completed a language comprehension task. FDA was used to decompose the high dimensional hemodynamic curves into the mean function and a few eigenfunctions to represent the overall trend and variation structures over time. Compared to the most popular GLM, we did not assume any parametric structure and let the data speak for itself. This analysis identified significant differences between the case and control groups in the oxygenated hemodynamic mean trends in the bilateral inferior frontal and left inferior posterior parietal brain regions. We also detected significant group differences in the deoxygenated hemodynamic mean trends in the right inferior posterior parietal cortex and left temporal parietal junction. These findings, using dramatically different approaches, experimental designs, data sets, and foci, were consistent with several other reports, confirming group differences in the importance of these two areas for syntax comprehension. The proposed FDA was consistent with the temporal characteristics of fNIRS, thus providing an alternative methodology for fNIRS analyses.

The analysis to understand temporal variation and long-range transport of aerosol over Northeast-Asia Using COMS, MI

NASA Astrophysics Data System (ADS)

KIM, M.; Kim, J.

2016-12-01

Numerous efforts to retrieve aerosol optical properties (AOPs) using satellite measurements have been accumulated for decades, resulted in several qualified data which can be used for the analysis of spatiotemporal characteristics of AOPs. However, the limitation in the instrument lifetime restricts temporal window of the analysis of long-term AOPs variation. In this point of view, single channel algorithm, which uses a single visible channel to retrieve aerosol optical depth (AOD), has an advantage to extent the time domain of the analysis. The Korean geostationary earth orbit (GEO) satellite, the Communication, Ocean and Meteorological Satellite (COMS) includes the single channel Meteorological Imager (MI), which can also be utilized for the retrieval of AOPs. Since the GEO satellite measurement has an advantage for continuous monitoring of AOPs over Northeast Asia, we can analyze the spatiotemporal characteristic of the aerosol using MI observations. In this study, we investigate the trend of AOD and also discuss the impact of long-range transport of aerosol on the temporal variation. Since the year 2010 when the COMS was launched, AODs over Northeast China and Yellow Sea region show 3.02 % and 2.74 % decrease per year, respectively, which are significant trends in spite of only 5-year short period. The decreasing behavior seems associated with the recent decreasing frequency of dust event over the region. But other Northeast Asia regions do not show clear temporal change. The accuracy of retrieved AOD can relates to the uncertainty of this trend analysis. According to the error analysis, cloud contamination and error in bright surface reflectance results in the accuracy of AOD. Therefore, improvements of cloud masking process and surface reflectance estimation in the developed single channel MI algorithm will be required for the future study.

Temporal correlations in population trends: Conservation implications from time-series analysis of diverse animal taxa

Treesearch

David Keith; H. Resit Akcakaya; Stuart H.M. Butchart; Ben Collen; Nicholas K. Dulvy; Elizabeth E. Holmes; Jeffrey A. Hutchings; Doug Keinath; Michael K. Schwartz; Andrew O. Shelton; Robin S. Waples

2015-01-01

Population trends play a large role in species risk assessments and conservation planning, and species are often considered threatened if their recent rate of decline meets certain thresholds, regardless how large the population is. But how reliable an indicator of extinction risk is a single estimate of population trend? Given the integral role this decline-...

Exploring spatial-temporal dynamics of fire regime features in mainland Spain

NASA Astrophysics Data System (ADS)

Jiménez-Ruano, Adrián; Rodrigues Mimbrero, Marcos; de la Riva Fernández, Juan

2017-10-01

This paper explores spatial-temporal dynamics in fire regime features, such as fire frequency, burnt area, large fires and natural- and human-caused fires, as an essential part of fire regime characterization. Changes in fire features are analysed at different spatial - regional and provincial/NUTS3 - levels, together with summer and winter temporal scales, using historical fire data from Spain for the period 1974-2013. Temporal shifts in fire features are investigated by means of change point detection procedures - Pettitt test, AMOC (at most one change), PELT (pruned exact linear time) and BinSeg (binary segmentation) - at a regional level to identify changes in the time series of the features. A trend analysis was conducted using the Mann-Kendall and Sen's slope tests at both the regional and NUTS3 level. Finally, we applied a principal component analysis (PCA) and varimax rotation to trend outputs - mainly Sen's slope values - to summarize overall temporal behaviour and to explore potential links in the evolution of fire features. Our results suggest that most fire features show remarkable shifts between the late 1980s and the first half of the 1990s. Mann-Kendall outputs revealed negative trends in the Mediterranean region. Results from Sen's slope suggest high spatial and intra-annual variability across the study area. Fire activity related to human sources seems to be experiencing an overall decrease in the northwestern provinces, particularly pronounced during summer. Similarly, the Hinterland and the Mediterranean coast are gradually becoming less fire affected. Finally, PCA enabled trends to be synthesized into four main components: winter fire frequency (PC1), summer burnt area (PC2), large fires (PC3) and natural fires (PC4).

Dynamic factor analysis of long-term growth trends of the intertidal seagrass Thalassia hemprichii in southern Taiwan

NASA Astrophysics Data System (ADS)

Kuo, Yi-Ming; Lin, Hsing-Juh

2010-01-01

We examined environmental factors which are most responsible for the 8-year temporal dynamics of the intertidal seagrass Thalassia hemprichii in southern Taiwan. A dynamic factor analysis (DFA), a dimension-reduction technique, was applied to identify common trends in a multivariate time series and the relationships between this series and interacting environmental variables. The results of dynamic factor models (DFMs) showed that the leaf growth rate of the seagrass was mainly influenced by salinity (Sal), tidal range (TR), turbidity ( K), and a common trend representing an unexplained variability in the observed time series. Sal was the primary variable that explained the temporal dynamics of the leaf growth rate compared to TR and K. K and TR had larger influences on the leaf growth rate in low- than in high-elevation beds. In addition to K, TR, and Sal, UV-B radiation (UV-B), sediment depth (SD), and a common trend accounted for long-term temporal variations of the above-ground biomass. Thus, K, TR, Sal, UV-B, and SD are the predominant environmental variables that described temporal growth variations of the intertidal seagrass T. hemprichii in southern Taiwan. In addition to environmental variables, human activities may be contributing to negative impacts on the seagrass beds; this human interference may have been responsible for the unexplained common trend in the DFMs. Due to successfully applying the DFA to analyze complicated ecological and environmental data in this study, important environmental variables and impacts of human activities along the coast should be taken into account when managing a coastal environment for the conservation of intertidal seagrass beds.

Colorectal cancer mortality trends in Serbia during 1991-2010: an age-period-cohort analysis and a joinpoint regression analysis.

PubMed

Ilic, Milena; Ilic, Irena

2016-06-22

For both men and women worldwide, colorectal cancer is among the leading causes of cancer-related death. This study aimed to assess the mortality trends of colorectal cancer in Serbia between 1991 and 2010, prior to the introduction of population-based screening. Joinpoint regression analysis was used to estimate average annual percent change (AAPC) with the corresponding 95% confidence interval (CI). Furthermore, age-period-cohort analysis was performed to examine the effects of birth cohort and calendar period on the observed temporal trends. We observed a significantly increased trend in colorectal cancer mortality in Serbia during the study period (AAPC = 1.6%, 95% CI 1.3%-1.8%). Colorectal cancer showed an increased mortality trend in both men (AAPC = 2.0%, 95% CI 1.7%-2.2%) and women (AAPC = 1.0%, 95% CI 0.6%-1.4%). The temporal trend of colorectal cancer mortality was significantly affected by birth cohort (P < 0.05), whereas the study period did not significantly affect the trend (P = 0.072). Colorectal cancer mortality increased for the first several birth cohorts in Serbia (from 1916 to 1955), followed by downward flexion for people born after the 1960s. According to comparability test, overall mortality trends for colon cancer and rectal and anal cancer were not parallel (the final selected model rejected parallelism, P < 0.05). We found that colorectal cancer mortality in Serbia increased considerably over the past two decades. Mortality increased particularly in men, but the trends were different according to age group and subsite. In Serbia, interventions to reduce colorectal cancer burden, especially the implementation of a national screening program, as well as treatment improvements and measures to encourage the adoption of a healthy lifestyle, are needed.

TREND ANALYSIS OF WATER QUALITY MONITORING DATA FOR COBB COUNTY, GEORGIA

EPA Science Inventory

The Cobb County Water Protection Division Water Quality Laboratory has conducted quarterly chemical monitoring from 1995-2005. Here we analyze these data for temporal trends at 45 sites in 10 Piedmont streams in the Chattahoochee and Etowah river basins. The strongest overall tre...

Advances in Temporal Analysis in Learning and Instruction

ERIC Educational Resources Information Center

Molenaar, Inge

2014-01-01

This paper focuses on a trend to analyse temporal characteristics of constructs important to learning and instruction. Different researchers have indicated that we should pay more attention to time in our research to enhance explanatory power and increase validity. Constructs formerly viewed as personal traits, such as self-regulated learning and…

Evaluating the power to detect temporal trends in fishery-independent time surveys: A case study based on gill nets set in the Ohio waters of Lake Erie for walleyes

USGS Publications Warehouse

Wagner, Tyler; Vandergoot, Christopher S.; Tyson, Jeff

2011-01-01

Fishery-independent (FI) surveys provide critical information used for the sustainable management and conservation of fish populations. Because fisheries management often requires the effects of management actions to be evaluated and detected within a relatively short time frame, it is important that research be directed toward FI survey evaluation, especially with respect to the ability to detect temporal trends. Using annual FI gill-net survey data for Lake Erie walleyes Sander vitreus collected from 1978 to 2006 as a case study, our goals were to (1) highlight the usefulness of hierarchical models for estimating spatial and temporal sources of variation in catch per effort (CPE); (2) demonstrate how the resulting variance estimates can be used to examine the statistical power to detect temporal trends in CPE in relation to sample size, duration of sampling, and decisions regarding what data are most appropriate for analysis; and (3) discuss recommendations for evaluating FI surveys and analyzing the resulting data to support fisheries management. This case study illustrated that the statistical power to detect temporal trends was low over relatively short sampling periods (e.g., 5–10 years) unless the annual decline in CPE reached 10–20%. For example, if 50 sites were sampled each year, a 10% annual decline in CPE would not be detected with more than 0.80 power until 15 years of sampling, and a 5% annual decline would not be detected with more than 0.8 power for approximately 22 years. Because the evaluation of FI surveys is essential for ensuring that trends in fish populations can be detected over management-relevant time periods, we suggest using a meta-analysis–type approach across systems to quantify sources of spatial and temporal variation. This approach can be used to evaluate and identify sampling designs that increase the ability of managers to make inferences about trends in fish stocks.

Evaluating the power to detect temporal trends in fishery independent surveys: A case study based on Gillnets Set in the Ohio waters of Lake Erie for walleye

USGS Publications Warehouse

Wagner, Tyler; Vandergoot, Christopher S.; Tyson, Jeff

2009-01-01

Fishery-independent (FI) surveys provide critical information used for the sustainable management and conservation of fish populations. Because fisheries management often requires the effects of management actions to be evaluated and detected within a relatively short time frame, it is important that research be directed toward FI survey evaluation, especially with respect to the ability to detect temporal trends. Using annual FI gill-net survey data for Lake Erie walleyes Sander vitreus collected from 1978 to 2006 as a case study, our goals were to (1) highlight the usefulness of hierarchical models for estimating spatial and temporal sources of variation in catch per effort (CPE); (2) demonstrate how the resulting variance estimates can be used to examine the statistical power to detect temporal trends in CPE in relation to sample size, duration of sampling, and decisions regarding what data are most appropriate for analysis; and (3) discuss recommendations for evaluating FI surveys and analyzing the resulting data to support fisheries management. This case study illustrated that the statistical power to detect temporal trends was low over relatively short sampling periods (e.g., 5–10 years) unless the annual decline in CPE reached 10–20%. For example, if 50 sites were sampled each year, a 10% annual decline in CPE would not be detected with more than 0.80 power until 15 years of sampling, and a 5% annual decline would not be detected with more than 0.8 power for approximately 22 years. Because the evaluation of FI surveys is essential for ensuring that trends in fish populations can be detected over management-relevant time periods, we suggest using a meta-analysis–type approach across systems to quantify sources of spatial and temporal variation. This approach can be used to evaluate and identify sampling designs that increase the ability of managers to make inferences about trends in fish stocks.

Spatio-temporal Trends of Climate Variability in North Carolina

NASA Astrophysics Data System (ADS)

Sayemuzzaman, Mohammad

Climatic trends in spatial and temporal variability of maximum temperature (Tmax), minimum temperature (Tmin), mean temperature (Tmean) and precipitation were evaluated for 249 ground-based stations in North Carolina for 1950-2009. The Mann-Kendall (MK), the Theil-Sen Approach (TSA) and the Sequential Mann-Kendall (SQMK) tests were applied to quantify the significance of trend, magnitude of trend and the trend shift, respectively. The lag-1 serial correlation and double mass curve techniques were used to address the data independency and homogeneity. The pre-whitening technique was used to eliminate the effect of auto correlation of the data series. The difference between minimum and maximum temperatures, and so the diurnal temperature range (DTR), at some stations was found to be decreasing on both an annual and a seasonal basis, with an overall increasing trend in the mean temperature. For precipitation, a statewide increasing trend in fall (highest in November) and decreasing trend in winter (highest in February) were detected. No pronounced increasing/decreasing trends were detected in annual, spring, and summer precipitation time series. Trend analysis on a spatial scale (for three physiographic regions: mountain, piedmont and coastal) revealed mixed results. Coastal zone exhibited increasing mean temperature (warming) trend as compared to other locations whereas mountain zone showed decreasing trend (cooling). Three main moisture components (precipitation, total cloud cover, and soil moisture) and the two major atmospheric circulation modes (North Atlantic Oscillation and Southern Oscillation) were used for correlative analysis purposes with the temperature (specifically with DTR) and precipitation trends. It appears that the moisture components are associated with DTR more than the circulation modes in North Carolina.

Spatiotemporal changes in vegetation net primary productivity in the arid region of Northwest China, 2001 to 2012

NASA Astrophysics Data System (ADS)

Li, Zhen; Pan, Jinghu

2018-03-01

Net primary productivity (NPP) is recognized as an important index of ecosystem conditions and a key variable of the terrestrial carbon cycle. It also represents the comprehensive effects of climate change and anthropogenic activity on terrestrial vegetation. In this study, the temporal-spatial pattern of NPP for the period 2001-2012 was analyzed using a remote sensing-based carbon model (i.e., the Carnegie-Ames-Stanford Approach, CASA) in addition to other methods, such as linear trend analysis, standard deviation, and the Hurst index. Temporally, NPP showed a significant increasing trend for the arid region of Northwest China (ARNC), with an annual increase of 2.327 g C. Maximum and minimum productivity values appeared in July and December, respectively. Spatially, the NPP was relatively stable in the temperate and warm-temperate desert regions of Northwest China, while temporally, it showed an increasing trend. However, some attention should be given to the northwestern warm-temperate desert region, where there is severe continuous degradation and only a slight improvement trend.

A power analysis for multivariate tests of temporal trend in species composition.

PubMed

Irvine, Kathryn M; Dinger, Eric C; Sarr, Daniel

2011-10-01

Long-term monitoring programs emphasize power analysis as a tool to determine the sampling effort necessary to effectively document ecologically significant changes in ecosystems. Programs that monitor entire multispecies assemblages require a method for determining the power of multivariate statistical models to detect trend. We provide a method to simulate presence-absence species assemblage data that are consistent with increasing or decreasing directional change in species composition within multiple sites. This step is the foundation for using Monte Carlo methods to approximate the power of any multivariate method for detecting temporal trends. We focus on comparing the power of the Mantel test, permutational multivariate analysis of variance, and constrained analysis of principal coordinates. We find that the power of the various methods we investigate is sensitive to the number of species in the community, univariate species patterns, and the number of sites sampled over time. For increasing directional change scenarios, constrained analysis of principal coordinates was as or more powerful than permutational multivariate analysis of variance, the Mantel test was the least powerful. However, in our investigation of decreasing directional change, the Mantel test was typically as or more powerful than the other models.

The solar dimming/brightening effect over the Mediterranean Basin in the period 1979-2012

NASA Astrophysics Data System (ADS)

Kambezidis, H. D.; Kaskaoutis, D. G.; Kalliampakos, G. K.; Rashki, A.; Wild, M.

2016-12-01

Numerous studies have shown that the solar radiation reaching the Earth's surface is subjected to multi-decadal variations with significant spatial and temporal heterogeneities in both magnitude and sign. Although several studies have examined the solar radiation trends over Europe, North America and Asia, the Mediterranean Basin has not been studied extensively. This work investigates the evolution and trends in the surface net short-wave radiation (NSWR, surface solar radiation - reflected) over the Mediterranean Basin during the period 1979-2012 using monthly re-analysis datasets from the Modern Era Retrospective-Analysis for Research and Applications (MERRA) and aims to shed light on the specific role of clouds on the NSWR trends. The solar dimming/brightening phenomenon is temporally and spatially analyzed over the Mediterranean Basin. The spatially-averaged NSWR over the whole Mediterranean Basin was found to increase in MERRA by +0.36 Wm-2 per decade, with higher rates over the western Mediterranean (+0.82 Wm-2 per decade), and especially during spring (March-April-May; +1.3 Wm-2 per decade). However, statistically significant trends in NSWR either for all-sky or clean-sky conditions are observed only in May. The increasing trends in NSWR are mostly associated with decreasing ones in cloud optical depth (COD), especially for the low (<700 hPa) clouds. The decreasing COD trends (less opaque clouds and/or decrease in absolute cloudiness) are more pronounced during spring, thus controlling the increasing tendency in NSWR. The NSWR trends for cloudless (clear) skies are influenced by changes in the water-vapor content or even variations in surface albedo to a lesser degree, whereas aerosols are temporally constant in MERRA. The slight negative trend (not statistically significant) in NSWR under clear skies for nearly all months and seasons implies a slight increasing trend in water vapor under a warming and more humid climatic scenario over the Mediterranean.

A spatiotemporal analysis of U.S. station temperature trends over the last century

NASA Astrophysics Data System (ADS)

Capparelli, V.; Franzke, C.; Vecchio, A.; Freeman, M. P.; Watkins, N. W.; Carbone, V.

2013-07-01

This study presents a nonlinear spatiotemporal analysis of 1167 station temperature records from the United States Historical Climatology Network covering the period from 1898 through 2008. We use the empirical mode decomposition method to extract the generally nonlinear trends of each station. The statistical significance of each trend is assessed against three null models of the background climate variability, represented by stochastic processes of increasing temporal correlation length. We find strong evidence that more than 50% of all stations experienced a significant trend over the last century with respect to all three null models. A spatiotemporal analysis reveals a significant cooling trend in the South-East and significant warming trends in the rest of the contiguous U.S. It also shows that the warming trend appears to have migrated equatorward. This shows the complex spatiotemporal evolution of climate change at local scales.

Market inefficiency identified by both single and multiple currency trends

NASA Astrophysics Data System (ADS)

Tokár, T.; Horváth, D.

2012-11-01

Many studies have shown that there are good reasons to claim very low predictability of currency returns; nevertheless, the deviations from true randomness exist which have potential predictive and prognostic power [J. James, Simple trend-following strategies in currency trading, Quantitative finance 3 (2003) C75-C77]. We analyze the local trends which are of the main focus of the technical analysis. In this article we introduced various statistical quantities examining role of single temporal discretized trend or multitude of grouped trends corresponding to different time delays. Our specific analysis based predominantly on Euro-dollar currency pair data at the one minute frequency suggests the importance of cumulative nonrandom effect of trends on the potential forecasting performance.

Combined multivariate statistical techniques, Water Pollution Index (WPI) and Daniel Trend Test methods to evaluate temporal and spatial variations and trends of water quality at Shanchong River in the Northwest Basin of Lake Fuxian, China.

PubMed

Wang, Quan; Wu, Xianhua; Zhao, Bin; Qin, Jie; Peng, Tingchun

2015-01-01

Understanding spatial and temporal variations in river water quality and quantitatively evaluating the trend of changes are important in order to study and efficiently manage water resources. In this study, an analysis of Water Pollution Index (WPI), Daniel Trend Test, Cluster Analysis and Discriminant Analysis are applied as an integrated approach to quantitatively explore the spatial and temporal variations and the latent sources of water pollution in the Shanchong River basin, Northwest Basin of Lake Fuxian, China. We group all field surveys into 2 clusters (dry season and rainy season). Moreover, 14 sampling sites have been grouped into 3 clusters for the rainy season (highly polluted, moderately polluted and less polluted sites) and 2 clusters for the dry season (highly polluted and less polluted sites) based on their similarities and the level of pollution during the two seasons. The results show that the main trend of pollution was aggravated during the transition from the dry to the rainy season. The Water Pollution Index of Total Nitrogen is the highest of all pollution parameters, whereas the Chemical Oxygen Demand (Chromium) is the lowest. Our results also show that the main sources of pollution are farming activities alongside the Shanchong River, soil erosion and fish culture at Shanchong River reservoir area and domestic sewage from scattered rural residential area. Our results suggest that strategies to prevent water pollutionat the Shanchong River basin need to focus on non-point pollution control by employing appropriate fertilizer formulas in farming, and take the measures of soil and water conservation at Shanchong reservoir area, and purifying sewage from scattered villages.

Combined Multivariate Statistical Techniques, Water Pollution Index (WPI) and Daniel Trend Test Methods to Evaluate Temporal and Spatial Variations and Trends of Water Quality at Shanchong River in the Northwest Basin of Lake Fuxian, China

PubMed Central

Wang, Quan; Wu, Xianhua; Zhao, Bin; Qin, Jie; Peng, Tingchun

2015-01-01

Understanding spatial and temporal variations in river water quality and quantitatively evaluating the trend of changes are important in order to study and efficiently manage water resources. In this study, an analysis of Water Pollution Index (WPI), Daniel Trend Test, Cluster Analysis and Discriminant Analysis are applied as an integrated approach to quantitatively explore the spatial and temporal variations and the latent sources of water pollution in the Shanchong River basin, Northwest Basin of Lake Fuxian, China. We group all field surveys into 2 clusters (dry season and rainy season). Moreover, 14 sampling sites have been grouped into 3 clusters for the rainy season (highly polluted, moderately polluted and less polluted sites) and 2 clusters for the dry season (highly polluted and less polluted sites) based on their similarities and the level of pollution during the two seasons. The results show that the main trend of pollution was aggravated during the transition from the dry to the rainy season. The Water Pollution Index of Total Nitrogen is the highest of all pollution parameters, whereas the Chemical Oxygen Demand (Chromium) is the lowest. Our results also show that the main sources of pollution are farming activities alongside the Shanchong River, soil erosion and fish culture at Shanchong River reservoir area and domestic sewage from scattered rural residential area. Our results suggest that strategies to prevent water pollutionat the Shanchong River basin need to focus on non-point pollution control by employing appropriate fertilizer formulas in farming, and take the measures of soil and water conservation at Shanchong reservoir area, and purifying sewage from scattered villages. PMID:25837673

Opportunities to improve monitoring of temporal trends with FIA panel data

Treesearch

Raymond Czaplewski; Michael Thompson

2009-01-01

The Forest Inventory and Analysis (FIA) Program of the Forest Service, Department of Agriculture, is an annual monitoring system for the entire United States. Each year, an independent "panel" of FIA field plots is measured. To improve accuracy, FIA uses the "Moving Average" or "Temporally Indifferent" method to combine estimates from...

Current status and temporal trend of heavy metals in farmland soil of the Yangtze River Delta Region: Field survey and meta-analysis.

PubMed

Shao, Diwei; Zhan, Yu; Zhou, Wenjun; Zhu, Lizhong

2016-12-01

While the spatial distributions of heavy metals in farmland soil of China have been comprehensively delineated, their temporal trends are rarely investigated but are important for environmental risk management. In this study, the current status and temporal trends of heavy metals in the farmland soil of Yangtze River Delta (YRD) were evaluated through field survey and meta-analysis. The field survey conducted in 2014 showed that the concentrations of Cd, Pb, Cu, Zn, and Ni in the farmland topsoil were 0.23 ± 0.14, 37.63 ± 15.60, 25.83 ± 41.62, 88.38 ± 43.30, and 29.21 ± 12.41 mg kg -1 (mean ± standard deviation), respectively. The heavy metals showed relatively higher concentrations on the borders among Zhejiang, Jiangsu, and Shanghai. In the meta-analysis, we selected 68 published studies related to heavy metal pollution in farmland topsoil of YRD from 2000 to the year (2014) when the field survey was conducted. The results show an increasing trend for Cd (p < 0.05; 0.0081 mg kg -1 year -1 ), a decreasing trend for Cu (p < 0.05; -0.80 mg kg -1 year -1 ), and no significant trend for Pb (p = 0.155), Zn (p = 0.746), and Ni (p = 0.305). The increasing rate of Cd from the meta-analysis is consistent with the rate (0.0013 mg kg -1 year -1 ) derived from the mass balance calculation for Cd, where atmospheric deposition originated from intensive coal combustion is considered as the main source of Cd in the topsoil. The decreasing trend of Cu is likely due to largely reduced application of copper-based agrochemicals. Environmental regulation and soil remediation are needed to protect food safety and ecosystem from heavy metal pollution, especially Cd. Copyright © 2016 Elsevier Ltd. All rights reserved.

Detecting trends in forest disturbance and recovery using yearly Landsat time series: 1. LandTrendr — Temporal segmentation algorithms

Treesearch

Robert E. Kennedy; Zhiqiang Yang; Warren B. Cohen

2010-01-01

We introduce and test LandTrendr (Landsat-based detection of Trends in Disturbance and Recovery), a new approach to extract spectral trajectories of land surface change from yearly Landsat time-series stacks (LTS). The method brings together two themes in time-series analysis of LTS: capture of short-duration events and smoothing of long-term trends. Our strategy is...

Forest resource trends in Illinois

Treesearch

Louis R. Iverson

1994-01-01

Even though forests occupy only 12% of the land area of Illinois, they play a valuable role in the health of the state's environment and that of its citizens. Many of these benefits have been reviewed in Forest Resources of Illinois: An Atlas and Analysis of Spatial and Temporal Trends (Iverson et al. 1989), and summarized in...

Spatial distribution and temporal trends of rainfall erosivity in mainland China for 1951-2010

Treesearch

Wei Qin; Qiankun Guo; Changqing Zuo; Zhijie Shan; Liang Ma; Ge Sun

2016-01-01

Rainfall erosivity is an important factor for estimating soil erosion rates. Understanding the spatial distributionand temporal trends of rainfall erosivity is especially critical for soil erosion risk assessment and soil conservationplanning in mainland China. However, reports on the spatial distribution and temporal trends of rainfall...

[Spatial-temporal evolution characterization of land subsidence by multi-temporal InSAR method and GIS technology].

PubMed

Chen, Bei-Bei; Gong, Hui-Li; Li, Xiao-Juan; Lei, Kun-Chao; Duan, Guang-Yao; Xie, Jin-Rong

2014-04-01

Long-term over-exploitation of underground resources, and static and dynamic load increase year by year influence the occurrence and development of regional land subsidence to a certain extent. Choosing 29 scenes Envisat ASAR images covering plain area of Beijing, China, the present paper used the multi-temporal InSAR method incorporating both persistent scatterer and small baseline approaches, and obtained monitoring information of regional land subsidence. Under different situation of space development and utilization, the authors chose five typical settlement areas; With classified information of land-use, multi-spectral remote sensing image, and geological data, and adopting GIS spatial analysis methods, the authors analyzed the time series evolution characteristics of uneven settlement. The comprehensive analysis results suggests that the complex situations of space development and utilization affect the trend of uneven settlement; the easier the situation of space development and utilization, the smaller the settlement gradient, and the less the uneven settlement trend.

Spatial and temporal analysis of fatal off-piste and backcountry avalanche accidents in Austria with a comparison of results in Switzerland, France, Italy and the US

NASA Astrophysics Data System (ADS)

Pfeifer, Christian; Höller, Peter; Zeileis, Achim

2018-02-01

In this article we analyzed spatial and temporal patterns of fatal Austrian avalanche accidents caused by backcountry and off-piste skiers and snowboarders within the winter periods 1967/1968-2015/2016. The data were based on reports of the Austrian Board for Alpine Safety and reports of the information services of the federal states. Using the date and the location of the recorded avalanche accidents, we were able to carry out spatial and temporal analyses applying generalized additive models and Markov random-field models. As a result of the trend analysis we noticed an increasing trend of backcountry and off-piste avalanche fatalities within the winter periods 1967/1968-2015/2016 (although slightly decreasing in recent years), which is in contradiction to the widespread opinion in Austria that the number of fatalities is constant over time. Additionally, we compared Austrian results with results of Switzerland, France, Italy and the US based on data from the International Commission of Alpine Rescue (ICAR). As a result of the spatial analysis, we noticed two hot spots of avalanche fatalities (Arlberg-Silvretta and Sölden). Because of the increasing trend and the rather narrow regional distribution of the fatalities, initiatives aimed at preventing avalanche accidents were highly recommended.

Spatio-Temporal Trends and Risk Factors for Shigella from 2001 to 2011 in Jiangsu Province, People's Republic of China

PubMed Central

Bao, Changjun; Hu, Jianli; Liu, Wendong; Liang, Qi; Wu, Ying; Norris, Jessie; Peng, Zhihang; Yu, Rongbin; Shen, Hongbing; Chen, Feng

2014-01-01

Objective This study aimed to describe the spatial and temporal trends of Shigella incidence rates in Jiangsu Province, People's Republic of China. It also intended to explore complex risk modes facilitating Shigella transmission. Methods County-level incidence rates were obtained for analysis using geographic information system (GIS) tools. Trend surface and incidence maps were established to describe geographic distributions. Spatio-temporal cluster analysis and autocorrelation analysis were used for detecting clusters. Based on the number of monthly Shigella cases, an autoregressive integrated moving average (ARIMA) model successfully established a time series model. A spatial correlation analysis and a case-control study were conducted to identify risk factors contributing to Shigella transmissions. Results The far southwestern and northwestern areas of Jiangsu were the most infected. A cluster was detected in southwestern Jiangsu (LLR = 11674.74, P<0.001). The time series model was established as ARIMA (1, 12, 0), which predicted well for cases from August to December, 2011. Highways and water sources potentially caused spatial variation in Shigella development in Jiangsu. The case-control study confirmed not washing hands before dinner (OR = 3.64) and not having access to a safe water source (OR = 2.04) as the main causes of Shigella in Jiangsu Province. Conclusion Improvement of sanitation and hygiene should be strengthened in economically developed counties, while access to a safe water supply in impoverished areas should be increased at the same time. PMID:24416167

Association of Internet search trends with suicide death in Taipei City, Taiwan, 2004-2009.

PubMed

Yang, Albert C; Tsai, Shi-Jen; Huang, Norden E; Peng, Chung-Kang

2011-07-01

Although Internet has become an important source for affected people seeking suicide information, the connection between Internet searches for suicide information and suicidal death remains largely unknown. This study aims to evaluate the association between suicide and Internet searches trends for 37 suicide-related terms representing major known risks of suicide. This study analyzes suicide death data in Taipei City, Taiwan and corresponding local Internet search trend data provided by Google Insights for Search during the period from January 2004 to December 2009. The investigation uses cross correlation analysis to estimate the temporal relationship between suicide and Internet search trends and multiple linear regression analysis to identify significant factors associated with suicide from a pool of search trend data that either coincides or precedes the suicide death. Results show that a set of suicide-related search terms, the trends of which either temporally coincided or preceded trends of suicide data, were associated with suicide death. These search factors varied among different suicide samples. Searches for "major depression" and "divorce" accounted for, at most, 30.2% of the variance in suicide data. When considering only leading suicide trends, searches for "divorce" and the pro-suicide term "complete guide of suicide," accounted for 22.7% of variance in suicide data. Appropriate filtering and detection of potentially harmful source in keyword-driven search results by search engine providers may be a reasonable strategy to reduce suicide deaths. Copyright © 2011 Elsevier B.V. All rights reserved.

Changes of the time-varying percentiles of daily extreme temperature in China

NASA Astrophysics Data System (ADS)

Li, Bin; Chen, Fang; Xu, Feng; Wang, Xinrui

2017-11-01

Identifying the air temperature frequency distributions and evaluating the trends in time-varying percentiles are very important for climate change studies. In order to get a better understanding of the recent temporal and spatial pattern of the temperature changes in China, we have calculated the trends in temporal-varying percentiles of the daily extreme air temperature firstly. Then we divide all the stations to get the spatial patterns for the percentile trends using the average linkage cluster analysis method. To make a comparison, the shifts of trends percentile frequency distribution from 1961-1985 to 1986-2010 are also examined. Important results in three aspects have been achieved: (1) In terms of the trends in temporal-varying percentiles of the daily extreme air temperature, the most intense warming for daily maximum air temperature (Tmax) was detected in the upper percentiles with a significant increasing tendency magnitude (>2.5 °C/50year), and the greatest warming for daily minimum air temperature (Tmin) occurred with very strong trends exceeding 4 °C/50year. (2) The relative coherent spatial patterns for the percentile trends were found, and stations for the whole country had been divided into three clusters. The three primary clusters were distributed regularly to some extent from north to south, indicating the possible large influence of the latitude. (3) The most significant shifts of trends percentile frequency distribution from 1961-1985 to 1986-2010 was found in Tmax. More than half part of the frequency distribution show negative trends less than -0.5 °C/50year in 1961-1985, while showing trends less than 2.5 °C/50year in 1986-2010.

A use case study on late stent thrombosis for ontology-based temporal reasoning and analysis.

PubMed

Clark, Kim; Sharma, Deepak; Qin, Rui; Chute, Christopher G; Tao, Cui

2014-01-01

In this paper, we show how we have applied the Clinical Narrative Temporal Relation Ontology (CNTRO) and its associated temporal reasoning system (the CNTRO Timeline Library) to trend temporal information within medical device adverse event report narratives. 238 narratives documenting occurrences of late stent thrombosis adverse events from the Food and Drug Administration's (FDA) Manufacturing and User Facility Device Experience (MAUDE) database were annotated and evaluated using the CNTRO Timeline Library to identify, order, and calculate the duration of temporal events. The CNTRO Timeline Library had a 95% accuracy in correctly ordering events within the 238 narratives. 41 narratives included an event in which the duration was documented, and the CNTRO Timeline Library had an 80% accuracy in correctly determining these durations. 77 narratives included documentation of a duration between events, and the CNTRO Timeline Library had a 76% accuracy in determining these durations. This paper also includes an example of how this temporal output from the CNTRO ontology can be used to verify recommendations for length of drug administration, and proposes that these same tools could be applied to other medical device adverse event narratives in order to identify currently unknown temporal trends.

Analysis of satellite precipitation over East Africa during last decades

NASA Astrophysics Data System (ADS)

Cattani, Elsa; Wenhaji Ndomeni, Claudine; Merino, Andrés; Levizzani, Vincenzo

2016-04-01

Daily accumulated precipitation time series from satellite retrieval algorithms (e.g., ARC2 and TAMSAT) are exploited to extract the spatial and temporal variability of East Africa (EA - 5°S-20°N, 28°E-52°E) precipitation during last decades (1983-2013). The Empirical Orthogonal Function (EOF) analysis is applied to precipitation time series to investigate the spatial and temporal variability in particular for October-November-December referred to as the short rain season. Moreover, the connection among EA's precipitation, sea surface temperature, and soil moisture is analyzed through the correlation with the dominant EOF modes of variability. Preliminary results concern the first two EOF's modes for the ARC2 data set. EOF1 is characterized by an inter-annual variability and a positive correlation between precipitation and El Niño, positive Indian Ocean Dipole mode, and soil moisture, while EOF2 shows a dipole structure of spatial variability associated with a longer scale temporal variability. This second dominant mode is mostly linked to sea surface temperature variations in the North Atlantic Ocean. Further analyses are carried out by computing the time series of the joint CCI/CLIVAR/JCOMM Expert Team on Climate Change Detection and Indices (ETCCDI, http://etccdi.pacificclimate.org/index.shtml), i.e. RX1day, RX5day, CDD, CDD, CWD, SDII, PRCPTOT, R10, R20. The purpose is to identify the occurrenes of extreme events (droughts and floods) and extract precipitation temporal variation by trend analysis (Mann-Kendall technique). Results for the ARC2 data set demonstrate the existence of a dipole spatial pattern in the linear trend of the time series of PRCPTOT (annual precipitation considering days with a rain rate > 1 mm) and SDII (average precipitation on wet days over a year). A negative trend is mainly present over West Ethiopia and Sudan, whereas a positive trend is exhibited over East Ethiopia and Somalia. CDD (maximum number of consecutive dry days) and CWD (maximum number of consecutive wet days) time series do not exhibit a similar behavior and trends are generally weaker with a lower significance level with respect to PRCPTOT and SDII.

A method to assess the inter-annual weather-dependent variability in air pollution concentration and deposition based on weather typing

NASA Astrophysics Data System (ADS)

Pleijel, Håkan; Grundström, Maria; Karlsson, Gunilla Pihl; Karlsson, Per Erik; Chen, Deliang

2016-02-01

Annual anomalies in air pollutant concentrations, and deposition (bulk and throughfall) of sulphate, nitrate and ammonium, in the Gothenburg region, south-west Sweden, were correlated with optimized linear combinations of the yearly frequency of Lamb Weather Types (LWTs) to determine the extent to which the year-to-year variation in pollution exposure can be partly explained by weather related variability. Air concentrations of urban NO2, CO, PM10, as well as O3 at both an urban and a rural monitoring site, and the deposition of sulphate, nitrate and ammonium for the period 1997-2010 were included in the analysis. Linear detrending of the time series was performed to estimate trend-independent anomalies. These estimated anomalies were subtracted from observed annual values. Then the statistical significance of temporal trends with and without LWT adjustment was tested. For the pollutants studied, the annual anomaly was well correlated with the annual LWT combination (R2 in the range 0.52-0.90). Some negative (annual average [NO2], ammonia bulk deposition) or positive (average urban [O3]) temporal trends became statistically significant (p < 0.05) when the LWT adjustment was applied. In all the cases but one (NH4 throughfall, for which no temporal trend existed) the significance of temporal trends became stronger with LWT adjustment. For nitrate and ammonium, the LWT based adjustment explained a larger fraction of the inter-annual variation for bulk deposition than for throughfall. This is probably linked to the longer time scale of canopy related dry deposition processes influencing throughfall being explained to a lesser extent by LWTs than the meteorological factors controlling bulk deposition. The proposed novel methodology can be used by authorities responsible for air pollution management, and by researchers studying temporal trends in pollution, to evaluate e.g. the relative importance of changes in emissions and weather variability in annual air pollution exposure.

NATIONAL STATUS AND TRENDS PROGRAM

EPA Science Inventory

Since 1984, the National Status and Trends (NS&T) Program has monitored, on a national scale, spatial and temporal trends of chemical contamination and biological responses to that contamination. Temporal trends are being monitored through the Mussel Watch project that analyzes m...

Spatial-temporal trend for mother-to-child transmission of HIV up to infancy and during pre-Option B+ in western Kenya, 2007-13.

PubMed

Waruru, Anthony; Achia, Thomas N O; Muttai, Hellen; Ng'ang'a, Lucy; Zielinski-Gutierrez, Emily; Ochanda, Boniface; Katana, Abraham; Young, Peter W; Tobias, James L; Juma, Peter; De Cock, Kevin M; Tylleskär, Thorkild

2018-01-01

Using spatial-temporal analyses to understand coverage and trends in elimination of mother-to-child transmission of HIV (e-MTCT) efforts may be helpful in ensuring timely services are delivered to the right place. We present spatial-temporal analysis of seven years of HIV early infant diagnosis (EID) data collected from 12 districts in western Kenya from January 2007 to November 2013, during pre-Option B+ use. We included in the analysis infants up to one year old. We performed trend analysis using extended Cochran-Mantel-Haenszel stratified test and logistic regression models to examine trends and associations of infant HIV status at first diagnosis with: early diagnosis (<8 weeks after birth), age at specimen collection, infant ever having breastfed, use of single dose nevirapine, and maternal antiretroviral therapy status. We examined these covariates and fitted spatial and spatial-temporal semiparametric Poisson regression models to explain HIV-infection rates using R-integrated nested Laplace approximation package. We calculated new infections per 100,000 live births and used Quantum GIS to map fitted MTCT estimates for each district in Nyanza region. Median age was two months, interquartile range 1.5-5.8 months. Unadjusted pooled positive rate was 11.8% in the seven-years period and declined from 19.7% in 2007 to 7.0% in 2013, p < 0.01. Uptake of testing ≤8 weeks after birth was under 50% in 2007 and increased to 64.1% by 2013, p < 0.01. By 2013, the overall standardized MTCT rate was 447 infections per 100,000 live births. Based on Bayesian deviance information criterion comparisons, the spatial-temporal model with maternal and infant covariates was best in explaining geographical variation in MTCT. Improved EID uptake and reduced MTCT rates are indicators of progress towards e-MTCT. Cojoined analysis of time and covariates in a spatial context provides a robust approach for explaining differences in programmatic impact over time. During this pre-Option B+ period, the prevention of mother to child transmission program in this region has not achieved e-MTCT target of ≤50 infections per 100,000 live births. Geographical disparities in program achievements may signify gaps in spatial distribution of e-MTCT efforts and could indicate areas needing further resources and interventions.

Spatial–temporal trend for mother-to-child transmission of HIV up to infancy and during pre-Option B+ in western Kenya, 2007–13

PubMed Central

Achia, Thomas N.O.; Muttai, Hellen; Ng’ang’a, Lucy; Zielinski-Gutierrez, Emily; Ochanda, Boniface; Katana, Abraham; Tobias, James L.; Juma, Peter; De Cock, Kevin M.

2018-01-01

Introduction Using spatial–temporal analyses to understand coverage and trends in elimination of mother-to-child transmission of HIV (e-MTCT) efforts may be helpful in ensuring timely services are delivered to the right place. We present spatial–temporal analysis of seven years of HIV early infant diagnosis (EID) data collected from 12 districts in western Kenya from January 2007 to November 2013, during pre-Option B+ use. Methods We included in the analysis infants up to one year old. We performed trend analysis using extended Cochran–Mantel–Haenszel stratified test and logistic regression models to examine trends and associations of infant HIV status at first diagnosis with: early diagnosis (<8 weeks after birth), age at specimen collection, infant ever having breastfed, use of single dose nevirapine, and maternal antiretroviral therapy status. We examined these covariates and fitted spatial and spatial–temporal semiparametric Poisson regression models to explain HIV-infection rates using R-integrated nested Laplace approximation package. We calculated new infections per 100,000 live births and used Quantum GIS to map fitted MTCT estimates for each district in Nyanza region. Results Median age was two months, interquartile range 1.5–5.8 months. Unadjusted pooled positive rate was 11.8% in the seven-years period and declined from 19.7% in 2007 to 7.0% in 2013, p < 0.01. Uptake of testing ≤8 weeks after birth was under 50% in 2007 and increased to 64.1% by 2013, p < 0.01. By 2013, the overall standardized MTCT rate was 447 infections per 100,000 live births. Based on Bayesian deviance information criterion comparisons, the spatial–temporal model with maternal and infant covariates was best in explaining geographical variation in MTCT. Discussion Improved EID uptake and reduced MTCT rates are indicators of progress towards e-MTCT. Cojoined analysis of time and covariates in a spatial context provides a robust approach for explaining differences in programmatic impact over time. Conclusion During this pre-Option B+ period, the prevention of mother to child transmission program in this region has not achieved e-MTCT target of ≤50 infections per 100,000 live births. Geographical disparities in program achievements may signify gaps in spatial distribution of e-MTCT efforts and could indicate areas needing further resources and interventions. PMID:29576942

Temporal trends and epidemiological aspects of ciguatera in French Polynesia: a 10-year analysis.

PubMed

Chateau-Degat, Marie-Ludivine; Dewailly, Eric; Cerf, Nicole; Nguyen, Ngoc Lam; Huin-Blondey, Marie-Odile; Hubert, Bruno; Laudon, François; Chansin, René

2007-04-01

The purpose of this study was to report the temporal trends of the incidence of ciguatera poisoning from 1992 to 2001 in French Polynesia. This retrospective study analysed 7842 cases of ciguatera disease recorded over a period of 10 years. The annual incidence varied from 26.3 to 41.9 per 10,000 person-years. An analysis of cases grouped by archipelago revealed differences in incidences (P < 0.0001) with the most remote archipelagos having the highest incidences. A detailed analysis on a sub-sample of recorded cases for which clinical information was available (n = 1824) confirmed the neurological and gastrointestinal nature of this seafood poisoning. The incidence of ciguatera poisoning appeared relatively stable during the 10 years of the study period. However, the gradient of remoteness observed suggests an adaptation of management of ciguatera disease to each archipelago.

Remotely Sensed Spatio-Temporal Variability of Snow Cover in Himalayan Region with Perspective of Climate Change

NASA Astrophysics Data System (ADS)

Dhakal, S.; Ojha, S.

2017-12-01

Climate change and its impact of water resource have gained tremendous attention among scientific committee, governments and other stakeholders since last couple of decades, especially in Himalayan region. In this study, we purpose remotely sensed measurements to monitor snow cover, both spatially and temporal, and assess climate change impact on water resource. The snow cover data from MODIS satellite (2000-2010) have been used to analyze some climate change indicators. In particular, the variability in the maximum snow extent with elevations, its temporal variability (8-day, monthly, seasonal and annual), its variation trend and its relation with temperature have been analyzed. The snow products used in this study are the maximum snow extent and fractional snow covers, which come in 8-day temporal and 500m and 0.05 degree spatial resolutions, respectively. The results showed a tremendous potential of the MODIS snow product for studying the spatial and temporal variability of snow as well as the study of climate change impact in large and inaccessible regions like the Himalayas. The snow area extent (SAE) (%) time series exhibits similar patterns during seven hydrological years, even though there are some deviations in the accumulation and melt periods. The analysis showed relatively well inverse relation between the daily mean temperature and SAE during the melting period. Some important trends of snow fall are also observed. In particular, the decreasing trend in January and increasing trend in late winter and early spring may be interpreted as a signal of a possible seasonal shift. However, it requires more years of data to verify this conclusion.

Temporal expression profiling of plasma proteins reveals oxidative stress in early stages of Type 1 Diabetes progression

DOE PAGES

Liu, Chih-Wei; Bramer, Lisa; Webb-Robertson, Bobbie-Jo; ...

2017-10-07

We report that blood markers other than islet autoantibodies are greatly needed to indicate the pancreatic beta cell destruction process as early as possible, and more accurately reflect the progression of Type 1 Diabetes Mellitus (T1D). To this end, a longitudinal proteomic profiling of human plasma using TMT-10plex-based LC-MS/MS analysis was performed to track temporal proteomic changes of T1D patients (n = 11) across 9 serial time points, spanning the period of T1D natural progression, in comparison with those of the matching healthy controls (n = 10). To our knowledge, the current study represents the largest (> 2000 proteins measured)more » longitudinal expression profiles of human plasma proteome in T1D research. By applying statistical trend analysis on the temporal expression patterns between T1D and controls, and Benjamini-Hochberg procedure for multiple-testing correction, 13 protein groups were regarded as having statistically significant differences during the entire follow-up period. Moreover, 16 protein groups, which play pivotal roles in response to oxidative stress, have consistently abnormal expression trend before seroconversion to islet autoimmunity. Importantly, the expression trends of two key reactive oxygen species-decomposing enzymes, Catalase and Superoxide dismutase were verified independently by ELISA.« less

Temporal expression profiling of plasma proteins reveals oxidative stress in early stages of Type 1 Diabetes progression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Chih-Wei; Bramer, Lisa; Webb-Robertson, Bobbie-Jo

We report that blood markers other than islet autoantibodies are greatly needed to indicate the pancreatic beta cell destruction process as early as possible, and more accurately reflect the progression of Type 1 Diabetes Mellitus (T1D). To this end, a longitudinal proteomic profiling of human plasma using TMT-10plex-based LC-MS/MS analysis was performed to track temporal proteomic changes of T1D patients (n = 11) across 9 serial time points, spanning the period of T1D natural progression, in comparison with those of the matching healthy controls (n = 10). To our knowledge, the current study represents the largest (> 2000 proteins measured)more » longitudinal expression profiles of human plasma proteome in T1D research. By applying statistical trend analysis on the temporal expression patterns between T1D and controls, and Benjamini-Hochberg procedure for multiple-testing correction, 13 protein groups were regarded as having statistically significant differences during the entire follow-up period. Moreover, 16 protein groups, which play pivotal roles in response to oxidative stress, have consistently abnormal expression trend before seroconversion to islet autoimmunity. Importantly, the expression trends of two key reactive oxygen species-decomposing enzymes, Catalase and Superoxide dismutase were verified independently by ELISA.« less

Predicting temporal trends in total absenteeism rates for civil service employees of a federal public health agency.

PubMed

Spears, D Ross; McNeil, Carrie; Warnock, Eli; Trapp, Jonathan; Oyinloye, Oluremi; Whitehurst, Vanessa; Decker, K C; Chapman, Sandy; Campbell, Morris; Meechan, Paul

2014-06-01

This study evaluates the predictability in temporal absences trends due to all causes (total absenteeism) among employees at a federal agency. The objective is to determine how leave trends vary within the year, and determine whether trends are predictable. Ten years of absenteeism data from an attendance system were analyzed for rates of total absence. Trends over a 10-year period followed predictable and regular patterns during a given year that correspond to major holiday periods. Temporal trends in leave among small, medium, and large facilities compared favorably with the agency as a whole. Temporal trends in total absenteeism rates for an organization can be determined using its attendance system. The ability to predict employee absenteeism rates can be extremely helpful for management in optimizing business performance and ensuring that an organization meets its mission.

Temperature trends and Urban Heat Island intensity mapping of the Las Vegas valley area

NASA Astrophysics Data System (ADS)

Black, Adam Leland

Modified urban climate regions that are warmer than rural areas at night are referred to as Urban Heat Islands or UHI. Islands of warmer air over a city can be 12 degrees Celsius greater than the surrounding cooler air. The exponential growth in Las Vegas for the last two decades provides an opportunity to detect gradual temperature changes influenced by an increasing presence of urban materials. This thesis compares ground based thermometric observations and satellite based remote sensing temperature observations to identify temperature trends and UHI areas caused by urban development. Analysis of temperature trends between 2000 and 2010 at ground weather stations has revealed a general cooling trend in the Las Vegas region. Results show that urban development accompanied by increased vegetation has a cooling effect in arid climates. Analysis of long term temperature trends at McCarran and Nellis weather stations show 2.4 K and 1.2 K rise in temperature over the last 60 years. The ground weather station temperature data is related to the land surface temperature images from the Landsat Thematic Mapper to estimate and evaluate urban heat island intensity for Las Vegas. Results show that spatial and temporal trends of temperature are related to the gradual change in urban landcover. UHI are mainly observed at the airport and in the industrial areas. This research provides useful insight into the temporal behavior of the Las Vegas area.

How Have Cancer Clinical Trial Eligibility Criteria Evolved Over Time?

PubMed Central

Yaman, Anil; Chakrabarti, Shreya; Sen, Anando; Weng, Chunhua

2016-01-01

Knowledge reuse of cancer trial designs may benefit from a temporal understanding of the evolution of the target populations of cancer studies over time. Therefore, we conducted a retrospective analysis of the trends of cancer trial eligibility criteria between 1999 and 2014. The yearly distributions of eligibility concepts for chemicals and drugs, procedures, observations, and medical conditions extracted from free-text eligibility criteria of 32,000 clinical trials for 89 cancer types were analyzed. We identified the concepts that trend upwards or downwards in all or selected cancer types, and the concepts that show anomalous trends for some cancers. Later, concept trends were studied in a disease-specific manner and illustrated for breast cancer. Criteria trends observed in this study are also validated and interpreted using evidence from the existing medical literature. This study contributes a method for concept trend analysis and original knowledge of the trends in cancer clinical trial eligibility criteria. PMID:27570681

Spatial and temporal trends in runoff at long-term streamgages within and near the Chesapeake Bay Watershed

USGS Publications Warehouse

Rice, Karen C.; Hirsch, Robert M.

2012-01-01

Long-term streamflow data within the Chesapeake Bay watershed and surrounding area were analyzed in an attempt to identify trends in streamflow. Data from 30 streamgages near and within the Chesapeake Bay watershed were selected from 1930 through 2010 for analysis. Streamflow data were converted to runoff and trend slopes in percent change per decade were calculated. Trend slopes for three runoff statistics (the 7-day minimum, the mean, and the 1-day maximum) were analyzed annually and seasonally. The slopes also were analyzed both spatially and temporally. The spatial results indicated that trend slopes in the northern half of the watershed were generally greater than those in the southern half. The temporal analysis was done by splitting the 80-year flow record into two subsets; records for 28 streamgages were analyzed for 1930 through 1969 and records for 30 streamgages were analyzed for 1970 through 2010. The mean of the data for all sites for each year were plotted so that the following datasets were analyzed: the 7-day minimum runoff for the north, the 7-day minimum runoff for the south, the mean runoff for the north, the mean runoff for the south, the 1-day maximum runoff for the north, and the 1-day maximum runoff for the south. Results indicated that the period 1930 through 1969 was statistically different from the period 1970 through 2010. For the 7-day minimum runoff and the mean runoff, the latter period had significantly higher streamflow than did the earlier period, although within those two periods no significant linear trends were identified. For the 1-day maximum runoff, no step trend or linear trend could be shown to be statistically significant for the north, although the south showed a mixture of an upward step trend accompanied by linear downtrends within the periods. In no case was a change identified that indicated an increasing rate of change over time, and no general pattern was identified of hydrologic conditions becoming "more extreme" over time.

Changes in Land Use Intensity Within the Don and Dnieper River Basins Following the Collapse of the Soviet Union as Revealed by Spatio-temporal Trend Analysis

NASA Astrophysics Data System (ADS)

Kovalskyy, V.; Henebry, G.

2007-12-01

We analyzed changes in trends of land surface phenology (LSP) within two major river basins in Western Eurasia. The basins of Don and Dnieper Rivers extend over 862,000 ha and include 17% of the impounded water surface area in the former Soviet Union. Major changes in agricultural practices occurring after 1991 led to some time drastic reductions in the cultivated area receiving fertilizers and the amount of water consumed for irrigation in addition to other macro-indicators of agricultural sector land use intensity. Image time series analysis can localize the extent, direction, and intensity of changes during the 1990s. Using vegetation index data from the AVHRR PAL and GIMMS datasets from 1982-1988 (Soviet period) and 1995-2000 (post-Soviet period) coupled with contemporary land cover maps from MODIS, we identified the spatial extent of temporal trends and assess their significance using seasonal Mann-Kendall tests adjusted for first-order autocorrelation. Roughly 90% of croplands and forested land in Dnieper Basin exhibited no significant trends during the Soviet period. The Don Basin had more significant positive trends during the Soviet period than the Dnieper Basin. There was a substantial disagreement between datasets on the extent of significant positive trends in Don croplands (35% for GIMMS vs. 8% for PAL) and in Don forests during Soviet period (38% for GIMMS vs. 27% for PAL). Although very little area in either basins showed significant negative trends during the Soviet period, substantial areas fell under significant negative trends during the post-Soviet period. We also found major disagreement on extent of significant negative trends in Don forests during post-Soviet period (6% for GIMMS vs. 24% for PAL). Even though, there are some significant disagreements between the datasets, there is no evidence of a consistent bias in the change analysis. Changes in irrigation water use may account for some of the changes in trend direction.

Trends in Controlled-Release Oxycodone (Oxycontin[R]) Prescribing among Medicaid Recipients in Kentucky, 1998-2002. Research Note

ERIC Educational Resources Information Center

Havens, Jennifer R.; Talbert, Jeffrey C.; Walker, Robert; Leedham, Cynthia; Leukefeld, Carl G.

2006-01-01

Context: Prescription opioid abuse has emerged as a public health problem, particularly in rural America. Purpose: To examine temporal and geographic trends in rates of controlled-release oxycodone (OxyContin) prescribing for Kentucky Medicaid recipients. Methods: A cross-sectional analysis was completed in which the state was divided into 3…

Multiple long-term trends and trend reversals dominate environmental conditions in a man-made freshwater reservoir.

PubMed

Znachor, Petr; Nedoma, Jiří; Hejzlar, Josef; Seďa, Jaromír; Kopáček, Jiří; Boukal, David; Mrkvička, Tomáš

2018-05-15

Man-made reservoirs are common across the world and provide a wide range of ecological services. Environmental conditions in riverine reservoirs are affected by the changing climate, catchment-wide processes and manipulations with the water level, and water abstraction from the reservoir. Long-term trends of environmental conditions in reservoirs thus reflect a wider range of drivers in comparison to lakes, which makes the understanding of reservoir dynamics more challenging. We analysed a 32-year time series of 36 environmental variables characterising weather, land use in the catchment, reservoir hydrochemistry, hydrology and light availability in the small, canyon-shaped Římov Reservoir in the Czech Republic to detect underlying trends, trend reversals and regime shifts. To do so, we fitted linear and piecewise linear regression and a regime shift model to the time series of mean annual values of each variable and to principal components produced by Principal Component Analysis. Models were weighted and ranked using Akaike information criterion and the model selection approach. Most environmental variables exhibited temporal changes that included time-varying trends and trend reversals. For instance, dissolved organic carbon showed a linear increasing trend while nitrate concentration or conductivity exemplified trend reversal. All trend reversals and cessations of temporal trends in reservoir hydrochemistry (except total phosphorus concentrations) occurred in the late 1980s and during 1990s as a consequence of dramatic socioeconomic changes. After a series of heavy rains in the late 1990s, an administrative decision to increase the flood-retention volume of the reservoir resulted in a significant regime shift in reservoir hydraulic conditions in 1999. Our analyses also highlight the utility of the model selection framework, based on relatively simple extensions of linear regression, to describe temporal trends in reservoir characteristics. This approach can provide a solid basis for a better understanding of processes in freshwater reservoirs. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of Temporal Semantic Shifts of Peer-to-Peer Communication in a Health-Related Online Community: Implications for Data-driven Health Promotion.

PubMed

Sridharan, Vishnupriya; Cohen, Trevor; Cobb, Nathan; Myneni, Sahiti

2016-01-01

With online social platforms gaining popularity as venues of behavior change, it is important to understand the ways in which these platforms facilitate peer interactions. In this paper, we characterize temporal trends in user communication through mapping of theoretically-linked semantic content. We used qualitative coding and automated text analysis to assign theoretical techniques to peer interactions in an online community for smoking cessation, subsequently facilitating temporal visualization of the observed techniques. Results indicate manifestation of several behavior change techniques such as feedback and monitoring' and 'rewards'. Automated methods yielded reasonable results (F-measure=0.77). Temporal trends among relapsers revealed reduction in communication after a relapse event. This social withdrawal may be attributed to failure guilt after the relapse. Results indicate significant change in thematic categories such as 'social support', 'natural consequences', and 'comparison of outcomes' pre and post relapse. Implications for development of behavioral support technologies that promote long-term abstinence are discussed.

Gas-phase polychlorinated biphenyl and hexachlorocyclohexane concentrations near the Great Lakes: a historical perspective.

PubMed

Buehler, Stephanie S; Basu, Ilora; Hites, Ronald A

2002-12-01

The Integrated Atmospheric Deposition Network (IADN) has been measuring gas-phase, polychlorinated biphenyl (PCB) concentrations at sites near Lakes Michigan and Superior for over a decade. Data through 2000 were used in this study to investigate PCB temporal trends in the Great Lakes atmosphere. Decreasing trends were found at both sites, and half-lives of approximately 20 yr were calculated using IADN data. However, when these data were supplemented by historical data for Lakes Michigan and Superior dating back to 1977, half-lives dropped to 10 and 6 yr, respectively. These latter half-lives agreed well with half-lives in other environmental compartments. Exponential curves fitted to the historical and IADN data indicated little decline in PCB concentrations in the basin since the mid-1990s. A similar historical analysis of alpha-and gamma-hexachlorocyclohexane (HCH) data indicated that IADN data were the best predictor of trends, resulting in half-lives of around 4 yr for both compounds. Gamma-HCH concentrations, however, have shown little decline in recent years, most likely because of its continuing use. PCB and alpha-HCH temporal trends indicated that bans on these substances have helped to remove them from the atmosphere. This work also showed that decades of data may be necessary to properly interpret long-term temporal trends in gas-phase organochlorine concentrations.

A geomatic methodology for spatio-temporal analysis of climatologic variables and water related diseases

NASA Astrophysics Data System (ADS)

Quentin, E.; Gómez Albores, M. A.; Díaz Delgado, C.

2009-04-01

The main objective of this research is to propose, by the way of geomatic developments, an integrated tool to analyze and model the spatio-temporal pattern of human diseases related to environmental conditions, in particular the ones that are linked to water resources. The geomatic developments follows four generic steps : requirement analysis, conceptual modeling, geomatic modeling and implementation (in Idrisi GIS software). A first development consists of the preprocessing of water, population and health data in order to facilitate the conversion and validation of tabular data into the required structure for spatio-temporal analysis. Three parallel developments follow : water balance, demographic state and evolution, epidemiological measures (morbidity and mortality rates, diseases burden). The new geomatic modules in their actual state have been tested on various regions of Mexico Republic (Lerma watershed, Chiapas state) focusing on diarrhea and vector borne diseases (dengue and malaria) and considering records over the last decade : a yearly as well as seasonal spreading trend can be observed in correlation with precipitation and temperature data. In an ecohealth perspective, the geomatic approach results particularly appropriate since one of its purposes is the integration of the various spatial themes implied in the study problem, environmental as anthropogenic. By the use of powerful spatial analysis functions, it permits the detection of spatial trends which, combined to the temporal evolution, can be of particularly use for example in climate change context, if sufficiently valid historical data can be obtain.

Spatio-temporal pattern analysis for evaluation of the spread of human infections with avian influenza A(H7N9) virus in China, 2013-2014.

PubMed

Dong, Wen; Yang, Kun; Xu, Quanli; Liu, Lin; Chen, Juan

2017-10-24

A large number (n = 460) of A(H7N9) human infections have been reported in China from March 2013 through December 2014, and H7N9 outbreaks in humans became an emerging issue for China health, which have caused numerous disease outbreaks in domestic poultry and wild bird populations, and threatened human health severely. The aims of this study were to investigate the directional trend of the epidemic and to identify the significant presence of spatial-temporal clustering of influenza A(H7N9) human cases between March 2013 and December 2014. Three distinct epidemic phases of A(H7N9) human infections were identified in this study. In each phase, standard deviational ellipse analysis was conducted to examine the directional trend of disease spreading, and retrospective space-time permutation scan statistic was then used to identify the spatio-temporal cluster patterns of H7N9 outbreaks in humans. The ever-changing location and the increasing size of the three identified standard deviational ellipses showed that the epidemic moved from east to southeast coast, and hence to some central regions, with a future epidemiological trend of continue dispersing to more central regions of China, and a few new human cases might also appear in parts of the western China. Furthermore, A(H7N9) human infections were clustering in space and time in the first two phases with five significant spatio-temporal clusters (p < 0.05), but there was no significant cluster identified in phase III. There was a new epidemiologic pattern that the decrease in significant spatio-temporal cluster of A(H7N9) human infections was accompanied with an obvious spatial expansion of the outbreaks during the study period, and identification of the spatio-temporal patterns of the epidemic can provide valuable insights for better understanding the spreading dynamics of the disease in China.

The human sex odds at birth after the atmospheric atomic bomb tests, after Chernobyl, and in the vicinity of nuclear facilities.

PubMed

Scherb, Hagen; Voigt, Kristina

2011-06-01

Ever since the discovery of the mutagenic properties of ionizing radiation, the possibility of birth sex odds shifts in exposed human populations was considered in the scientific community. Positive evidence, however weak, was obtained after the atomic bombing of Japan. We previously investigated trends in the sex odds before and after the Chernobyl Nuclear Power Plant accident. In a pilot study, combined data from the Czech Republic, Denmark, Finland, Germany, Hungary, Norway, Poland, and Sweden between 1982 and 1992 showed a downward trend in the sex odds and a significant jump in 1987, the year immediately after Chernobyl. Moreover, a significant positive association of the sex odds between 1986 and 1991 with Chernobyl fallout at the district level in Germany was observed. Both of these findings, temporality (effect after exposure) and dose response association, yield evidence of causality. The primary aim of this study was to investigate longer time periods (1950-2007) in all of Europe and in the USA with emphasis on the global atmospheric atomic bomb test fallout and on the Chernobyl accident. To obtain further evidence, we also analyze sex odds data near nuclear facilities in Germany and Switzerland. DATA AND STATISTICAL METHODS: National gender-specific annual live births data for 39 European countries from 1975 to 2007 were compiled using the pertinent internet data bases provided by the World Health Organization, United Nations, Council of Europe, and EUROSTAT. For a synoptic re-analysis of the period 1950 to 1990, published data from the USA and from a predominantly western and less Chernobyl-exposed part of Europe were studied additionally. To assess spatial, temporal, as well as spatial-temporal trends in the sex odds and to investigate possible changes in those trends after the atomic bomb tests, after Chernobyl, and in the vicinity of nuclear facilities, we applied ordinary linear logistic regression. Region-specific and eventually changing spatial-temporal trends were analyzed using dummy variables coding for continents, countries, districts, municipalities, time periods, and appropriate spatial-temporal interactions. The predominantly western European sex odds trend together with the US sex odds trend (1950-1990 each) show a similar behavior. Both trends are consistent with a uniform reduction from 1950 to 1964, an increase from 1964 to 1975 that may be associated with delayed global atomic bomb test fallout released prior to the Partial Test Ban Treaty in 1963 and again a more or less constant decrease from 1975 to 1990. In practically all of Europe, including eastern European countries, from 1975 to 1986, and in the USA from 1975 to 2002, there were highly significant uniform downward trends in the sex odds with a reduction of 0.22% to 0.25% per 10 years. In contrast to the USA, in Europe there was a highly significant jump of the sex odds of 0.20% in the year 1987 following Chernobyl. From 1987 to 2000, the European sex odds trend reversed its sign and went upward, highly significantly so, with 0.42% per 10 years relative to the downward trend before Chernobyl. The global secular trend analyses are corroborated by the analysis of spatial-temporal sex odds trends near nuclear facilities (NF) in Germany and Switzerland. Within 35 km distance from those NF, the sex odds increase significantly in the range of 0.30% to 0.40% during NF operating time. The atmospheric atomic bomb test fallout affected the human sex odds at birth overall, and the Chernobyl fallout had a similar impact in Europe and parts of Asia. The birth sex odds near nuclear facilities are also distorted. The persistently disturbed secular human sex odds trends allow the estimation of the global deficit of births in the range of several millions.

Spatio-temporal analysis of annual rainfall in Crete, Greece

NASA Astrophysics Data System (ADS)

Varouchakis, Emmanouil A.; Corzo, Gerald A.; Karatzas, George P.; Kotsopoulou, Anastasia

2018-03-01

Analysis of rainfall data from the island of Crete, Greece was performed to identify key hydrological years and return periods as well as to analyze the inter-annual behavior of the rainfall variability during the period 1981-2014. The rainfall spatial distribution was also examined in detail to identify vulnerable areas of the island. Data analysis using statistical tools and spectral analysis were applied to investigate and interpret the temporal course of the available rainfall data set. In addition, spatial analysis techniques were applied and compared to determine the rainfall spatial distribution on the island of Crete. The analysis presented that in contrast to Regional Climate Model estimations, rainfall rates have not decreased, while return periods vary depending on seasonality and geographic location. A small but statistical significant increasing trend was detected in the inter-annual rainfall variations as well as a significant rainfall cycle almost every 8 years. In addition, statistically significant correlation of the island's rainfall variability with the North Atlantic Oscillation is identified for the examined period. On the other hand, regression kriging method combining surface elevation as secondary information improved the estimation of the annual rainfall spatial variability on the island of Crete by 70% compared to ordinary kriging. The rainfall spatial and temporal trends on the island of Crete have variable characteristics that depend on the geographical area and on the hydrological period.

[Spatio-temporal variation of drought condition during 1961 to 2012 based on composite index of meteorological drought in Altay region, China].

PubMed

Wu, Yan-feng; Bake, Batur; Li, Wei; Wei, Xiao-qin; Wozatihan, Jiayinaguli; Rasulov, Hamid

2015-02-01

Based on the daily meteorological data of seven stations in Altay region, China, this study investigated the temporal ( seasonal, inter-annual and decadal) and spatial variations of drought by using composite index of meteorological drought, as well as trend analysis, M-K abrupt analysis, wavelet analysis and interpolation tools in ArcGIS. The results indicated that the composite index of meteorological drought could reflect the drought condition in Altay region well. Although the frequency and the covered area of both inter-annual and seasonal droughts presented decreasing trends in the recent 52 a, the drought was still serious when considering the annual drought. The frequencies of inter-annual and spring droughts had no abrupt changes, whereas the frequencies of inter-summer, autumn and winter droughts had abrupt changes during the past 52 a. A significant periodic trend was also observed for the frequencies of inter-annual and seasonal droughts. The distribution of frequency and covered area suggested that the conditions of drought were heavily serious in Qinghe County, moderately serious in Altay City, Fuyun County, Buerjin County and Fuhai County, and slightly serious in Habahe County and Jimunai County.

Towards understanding temporal and spatial dynamics of seagrass landscapes using time-series remote sensing

NASA Astrophysics Data System (ADS)

Lyons, Mitchell B.; Roelfsema, Chris M.; Phinn, Stuart R.

2013-03-01

The spatial and temporal dynamics of seagrasses have been well studied at the leaf to patch scales, however, the link to large spatial extent landscape and population dynamics is still unresolved in seagrass ecology. Traditional remote sensing approaches have lacked the temporal resolution and consistency to appropriately address this issue. This study uses two high temporal resolution time-series of thematic seagrass cover maps to examine the spatial and temporal dynamics of seagrass at both an inter- and intra-annual time scales, one of the first globally to do so at this scale. Previous work by the authors developed an object-based approach to map seagrass cover level distribution from a long term archive of Landsat TM and ETM+ images on the Eastern Banks (≈200 km2), Moreton Bay, Australia. In this work a range of trend and time-series analysis methods are demonstrated for a time-series of 23 annual maps from 1988 to 2010 and a time-series of 16 monthly maps during 2008-2010. Significant new insight was presented regarding the inter- and intra-annual dynamics of seagrass persistence over time, seagrass cover level variability, seagrass cover level trajectory, and change in area of seagrass and cover levels over time. Overall we found that there was no significant decline in total seagrass area on the Eastern Banks, but there was a significant decline in seagrass cover level condition. A case study of two smaller communities within the Eastern Banks that experienced a decline in both overall seagrass area and condition are examined in detail, highlighting possible differences in environmental and process drivers. We demonstrate how trend and time-series analysis enabled seagrass distribution to be appropriately assessed in context of its spatial and temporal history and provides the ability to not only quantify change, but also describe the type of change. We also demonstrate the potential use of time-series analysis products to investigate seagrass growth and decline as well as the processes that drive it. This study demonstrates clear benefits over traditional seagrass mapping and monitoring approaches, and provides a proof of concept for the use of trend and time-series analysis of remotely sensed seagrass products to benefit current endeavours in seagrass ecology.

Trend analysis of the aerosol optical depth from fusion of MISR and MODIS retrievals over China

NASA Astrophysics Data System (ADS)

Guo, Jing; Gu, Xingfa; Yu, Tao; Cheng, Tianhai; Chen, Hao

2014-03-01

Atmospheric aerosol plays an important role in the climate change though direct and indirect processes. In order to evaluate the effects of aerosols on climate, it is necessary to have a research on their spatial and temporal distributions. Satellite aerosol remote sensing is a developing technology that may provide good temporal sampling and superior spatial coverage to study aerosols. The Moderate Resolution Imaging Spectroradiometer (MODIS) and Multi-angle Imaging Spectroradiometer (MISR) have provided aerosol observations since 2000, with large coverage and high accuracy. However, due to the complex surface, cloud contamination, and aerosol models used in the retrieving process, the uncertainties still exist in current satellite aerosol products. There are several observed differences in comparing the MISR and MODIS AOD data with the AERONET AOD. Combing multiple sensors could reduce uncertainties and improve observational accuracy. The validation results reveal that a better agreement between fusion AOD and AERONET AOD. The results confirm that the fusion AOD values are more accurate than single sensor. We have researched the trend analysis of the aerosol properties over China based on nine-year (2002-2010) fusion data. Compared with trend analysis in Jingjintang and Yangtze River Delta, the accuracy has increased by 5% and 3%, respectively. It is obvious that the increasing trend of the AOD occurred in Yangtze River Delta, where human activities may be the main source of the increasing AOD.

Trend analysis of the Aerosol Optical Thickness and Ångström Exponent derived from the global AERONET spectral observations

NASA Astrophysics Data System (ADS)

Yoon, J.; von Hoyningen-Huene, W.; Kokhanovsky, A. A.; Vountas, M.; Burrows, J. P.

2011-08-01

Regular aerosol observations based on well-calibrated instruments have led to a better understanding of the aerosol radiative budget on Earth. In recent years, these instruments have played an important role in the determination of the increase of anthropogenic aerosols by means of long-term studies. Only few investigations regarding long-term trends of aerosol optical characteristics (e.g. Aerosol Optical Thickness (AOT) and Ångström Exponent (ÅE)) have been derived from ground-based observations. This paper aims to derive and discuss linear trends of AOT (440, 675, 870, and 1020 nm) and ÅE (440-870 nm) using AErosol RObotic NETwork (AERONET) spectral observations. Additionally, temporal trends of Coarse- and Fine-mode dominant AOTs (CAOT and FAOT) have been estimated by applying an aerosol classification based on accurate ÅE and Ångström Exponent Difference (ÅED). In order to take into account the fact that cloud disturbance is having a significant influence on the trend analysis of aerosols, we introduce a weighted least squares regression depending on two weights: (1) monthly standard deviation and (2) Number of Observations (NO) per month. Temporal increase of FAOTs prevails over regions dominated by emerging economy or slash-burn agriculture in East Asia and South Africa. On the other hand, insignificant or negative trends for FAOTs are detected over Western Europe and North America. Over desert regions, both increase and decrease of CAOTs are observed depending on meteorological conditions.

SWiFT site atmospheric characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelley, Christopher Lee; Ennis, Brandon Lee

2016-01-01

Historical meteorological tall tower data are analyzed from the Texas Tech University 200 m tower to characterize the atmospheric trends of the Scaled Wind Farm Technologies (SWiFT) site. In this report the data are analyzed to reveal bulk atmospheric trends, temporal trends and correlations of atmospheric variables. Through this analysis for the SWiFT turbines the site International Electrotechnical Commission (IEC) classification is determined to be class III-C. Averages and distributions of atmospheric variables are shown, revealing large fluctuations and the importance of understanding the actual site trends as opposed to simply using averages. The site is significantly directional with themore » average wind speed from the south, and particularly so in summer and fall. Site temporal trends are analyzed from both seasonal (time of the year) to daily (hour of the day) perspectives. Atmospheric stability is seen to vary most with time of day and less with time of year. Turbulence intensity is highly correlated with stability, and typical daytime unstable conditions see double the level of turbulence intensity versus that experienced during the average stable night. Shear, veer and atmospheric stability correlations are shown, where shear and veer are both highest for stable atmospheric conditions. An analysis of the Texas Tech University tower anemometer measurements is performed which reveals the extent of the tower shadow effects and sonic tilt misalignment.« less

Trends in bromide wet deposition concentrations in the contiguous United States, 2001-2016.

PubMed

Wetherbee, Gregory A; Lehmann, Christopher M B; Kerschner, Brian M; Ludtke, Amy S; Green, Lee A; Rhodes, Mark F

2018-02-01

Bromide (Br - ) and other solute concentration data from wet deposition samples collected and analyzed by the National Atmospheric Deposition Program (NADP) from 2001 to 2016, were statistically analyzed for trends both geographically and temporally by precipitation type. Analysis was limited to NADP sites in the contiguous 48 United States. The Br - concentrations for this time period had a high number of values censored at the detection limits with greater than 86 percent of sample concentrations below analytical detection. Bromide was more frequently detected at NADP sites in coastal regions. Analysis using specialized statistical techniques for censored data revealed that Br - concentrations varied by precipitation type with higher concentrations usually observed in liquid versus precipitation containing snow. Negative temporal trends in Br - wet deposition concentrations were observed at a majority of NADP sites; approximately 25 percent of these trend values were statistically significant at less than 0.05 to 0.10 significance levels. Potential causes for the negative trends were explored, including annual and seasonal changes in precipitation depth, reduced emissions of methyl bromide (CH 3 Br) from coastal wetlands, and declining industrial use of bromine compounds. The results indicate that Br - in non-coastal wet-deposition comes mainly from long-range transport, not local sources. Correlations between Br - , chloride, and nitrate concentrations also were evaluated. Published by Elsevier Ltd.

Analysis of spatial and temporal rainfall trends in Sicily during the 1921-2012 period

NASA Astrophysics Data System (ADS)

Liuzzo, Lorena; Bono, Enrico; Sammartano, Vincenzo; Freni, Gabriele

2016-10-01

Precipitation patterns worldwide are changing under the effects of global warming. The impacts of these changes could dramatically affect the hydrological cycle and, consequently, the availability of water resources. In order to improve the quality and reliability of forecasting models, it is important to analyse historical precipitation data to account for possible future changes. For these reasons, a large number of studies have recently been carried out with the aim of investigating the existence of statistically significant trends in precipitation at different spatial and temporal scales. In this paper, the existence of statistically significant trends in rainfall from observational datasets, which were measured by 245 rain gauges over Sicily (Italy) during the 1921-2012 period, was investigated. Annual, seasonal and monthly time series were examined using the Mann-Kendall non-parametric statistical test to detect statistically significant trends at local and regional scales, and their significance levels were assessed. Prior to the application of the Mann-Kendall test, the historical dataset was completed using a geostatistical spatial interpolation technique, the residual ordinary kriging, and then processed to remove the influence of serial correlation on the test results, applying the procedure of trend-free pre-whitening. Once the trends at each site were identified, the spatial patterns of the detected trends were examined using spatial interpolation techniques. Furthermore, focusing on the 30 years from 1981 to 2012, the trend analysis was repeated with the aim of detecting short-term trends or possible changes in the direction of the trends. Finally, the effect of climate change on the seasonal distribution of rainfall during the year was investigated by analysing the trend in the precipitation concentration index. The application of the Mann-Kendall test to the rainfall data provided evidence of a general decrease in precipitation in Sicily during the 1921-2012 period. Downward trends frequently occurred during the autumn and winter months. However, an increase in total annual precipitation was detected during the period from 1981 to 2012.

Summary statistics and trend analysis of water-quality data at sites in the Gila River basin, New Mexico and Arizona

USGS Publications Warehouse

Baldys, Stanley; Ham, L.K.; Fossum, K.D.

1995-01-01

Summary statistics and temporal trends for 19 water-chemistry constituents and for turbidity were computed for 13 study sites in the Gila River basin, Arizona and New Mexico. A nonparametric technique, the seasonal Kendall tau test for flow-adjusted data, was used to analyze temporal changes in water-chemistry data. For the 19 selected constituents and turbidity, decreasing trends in concentrations outnumbered increasing trends by more than two to one. Decreasing trends in concentrations of constituents were found for 49 data sets at the 13 study sites. Gila River at Calva and Gila River above diversions, at Gillespie Dam (eight each) had the most decreasing trends for individual sites. The largest number of decreasing trends measured for a constituent was six for dissolved lead. The next largest number of decreasing trends for a constituent was for dissolved solids and total manganese (five each). Hardness, dissolved sodium, and dissolved chloride had decreasing trends at four of the study sites. Increasing trends in concen- trations of constituents were found for 24 data sets at the 13 study sites. The largest number of increasing trends measured for a single constituent was for pH (four), dissolved sulfate (three), dissolved chromium (three) and total manganese (three). Increased concentrations of constituents generally were found in three areas in the basin-at Pinal Creek above Inspiration Dam, at sites above reservoirs, and at sites on the main stem of the Gila River from Gillespie Dam to the mouth.

Study on temporal and spatial variations of urban land use based on land change data

NASA Astrophysics Data System (ADS)

Jiang, Ping; Liu, Yanfang; Fan, Min; Zhang, Yang

2009-10-01

With the rapid development of urbanization, demands of urban land increase in succession, hence, to analyze temporal and spatial variations of urban land use becomes more and more important. In this paper, the principle of trend surface analysis and formula of urban land sprawl index ( ULSI) are expatiated at first, and then based on land change data of Jiayu county, the author fits quadratic trend surface by choosing urban land area as dependent variable and urbanization and GDP as independent variables from 1996 to 2006, draws isoline of trend surface and residual values; and then urban land sprawl indexes of towns are calculated on the basis of urban land area of 1996 and 2006 and distribution map of ULSI is plotted. After analyzing those results, we can conclude that there is consanguineous relationship between urban land area and urbanization, economic level etc.

Identifying food deserts and swamps based on relative healthy food access: a spatio-temporal Bayesian approach.

PubMed

Luan, Hui; Law, Jane; Quick, Matthew

2015-12-30

Obesity and other adverse health outcomes are influenced by individual- and neighbourhood-scale risk factors, including the food environment. At the small-area scale, past research has analysed spatial patterns of food environments for one time period, overlooking how food environments change over time. Further, past research has infrequently analysed relative healthy food access (RHFA), a measure that is more representative of food purchasing and consumption behaviours than absolute outlet density. This research applies a Bayesian hierarchical model to analyse the spatio-temporal patterns of RHFA in the Region of Waterloo, Canada, from 2011 to 2014 at the small-area level. RHFA is calculated as the proportion of healthy food outlets (healthy outlets/healthy + unhealthy outlets) within 4-km from each small-area. This model measures spatial autocorrelation of RHFA, temporal trend of RHFA for the study region, and spatio-temporal trends of RHFA for small-areas. For the study region, a significant decreasing trend in RHFA is observed (-0.024), suggesting that food swamps have become more prevalent during the study period. For small-areas, significant decreasing temporal trends in RHFA were observed for all small-areas. Specific small-areas located in south Waterloo, north Kitchener, and southeast Cambridge exhibited the steepest decreasing spatio-temporal trends and are classified as spatio-temporal food swamps. This research demonstrates a Bayesian spatio-temporal modelling approach to analyse RHFA at the small-area scale. Results suggest that food swamps are more prevalent than food deserts in the Region of Waterloo. Analysing spatio-temporal trends of RHFA improves understanding of local food environment, highlighting specific small-areas where policies should be targeted to increase RHFA and reduce risk factors of adverse health outcomes such as obesity.

Temporal frequency of radio emissions for the April 25, 1984 flare

NASA Technical Reports Server (NTRS)

Wells, G. D.; Hausman, B. A.; Kroehl, H. W.

1986-01-01

The National Geophysical Data Center archives data of the solar-terrestrial environment. The USAF Radio Solar Telescope Network (RSTN) data allow performance of time series analysis to determine temporal oscillations as low as three seconds. The X13/3B flare which erupted in region 4474 (S12E43) on the 24 to 25 of April 1984, was selected. The soft X-rays, 1 to 8 A, remained above X-levels for 50 minutes and the radio emissions measured at Learmonth Solar Observatory reached a maximum of 3.15 x 10 to the 5th power SFUs at 410 MHz at 0000UT. A power spectral analysis of the fixed frequency RSTN data from Learmonth shows possible quasi-periodic fluctuations in the range two to ten seconds. Repetition rates or quasi-periodicities, in the case of the power spectral analysis, generally showed the same trends as the average solar radio flux at 245 and 8800 MHz. The quasi-periodicities at 1415 MHz showed no such trends.

Spatial and temporal characteristics of droughts in Luanhe River basin, China

NASA Astrophysics Data System (ADS)

Wang, Yixuan; Zhang, Ting; Chen, Xu; Li, Jianzhu; Feng, Ping

2018-02-01

The spatial and temporal characteristics of drought are investigated for Luanhe River basin, using monthly precipitation data from 26 stations covering the common period of 1958-2011. The spatial pattern of drought was assessed by applying principal component analysis (PCA) to the Standardized Precipitation Index (SPI) computed on 3- and 12-month time scales. In addition, annual SPI and seasonal SPIs (including spring SPI, summer SPI, autumn SPI, and winter SPI) were also defined and considered in this study to characterize seasonal and annual drought conditions, respectively. For all seven SPI cases, three distinctive sub-regions with different temporal evolutions of droughts are well identified, respectively, representing the southeast, middle, and northwest of the Luanhe River basin. The Mann-Kendall (MK) trend test with a trend-free pre-whitening (TFPW) procedure and Sen's method were used to determine the temporal trends in the annual and seasonal SPI time series. The continuous wavelet transform (CWT) was employed for further detecting the periodical features of drought condition in each sub-region. Results of MK and Sen's tests show a general tendency of intensification in summer drought over the entire basin, while a significant mitigating trend in spring drought. On the whole, an aggravating trend of inter-annual drought is discovered across the basin. Based on the CWT, the drought variability in the basin is generally dominated by 16- to 64-month cycles, and the 2- to 6-year cycles appear to be obvious when concerned with annual and seasonal droughts. Furthermore, a cross wavelet analysis was performed to examine the possible links between the drought conditions and large-scale climate patterns. The teleconnections of ENSO, NAO, PDO, and AMO show significant influences on the regional droughts principally concentrated in the 16- to 64-month period, maybe responsible for the physical causes of the cyclical behavior of drought occurrences. PDO and AMO also highlight a noteworthy correlation with drought variability on a decadal scale (around 128-month period). The findings of this study will provide valuable references for regional drought mitigation and water resource management.

Temporal trend and source apportionment of water pollution in different functional zones of Qiantang River, China.

PubMed

Su, Shiliang; Li, Dan; Zhang, Qi; Xiao, Rui; Huang, Fang; Wu, Jiaping

2011-02-01

The increasingly serious river water pollution in developing countries poses great threat to environmental health and human welfare. The assignment of river function to specific uses, known as zoning, is a useful tool to reveal variations of water environmental adaptability to human impact. Therefore, characterizing the temporal trend and identifying responsible pollution sources in different functional zones could greatly improve our knowledge about human impacts on the river water environment. The aim of this study is to obtain a deeper understanding of temporal trends and sources of water pollution in different functional zones with a case study of the Qiantang River, China. Measurement data were obtained and pretreated for 13 variables from 41 monitoring sites in four categories of functional zones during the period 1996-2004. An exploratory approach, which combines smoothing and non-parametric statistical tests, was applied to characterize trends of four significant parameters (permanganate index, ammonia nitrogen, total cadmium and fluoride) accounting for differences among different functional zones identified by discriminant analysis. Aided by GIS, yearly pollution index (PI) for each monitoring site was further mapped to compare the within-group variations in temporal dynamics for different functional zones. Rotated principal component analysis and receptor model (absolute principle component score-multiple linear regression, APCS-MLR) revealed that potential pollution sources and their corresponding contributions varied among the four functional zones. Variations of APCS values for each site of one functional zone as well as their annual average values highlighted the uncertainties associated with cross space-time effects in source apportionment. All these results reinforce the notion that the concept of zoning should be taken seriously in water pollution control. Being applicable to other rivers, the framework of management-oriented source apportionment is thus believed to have potentials to offer new insights into water management and advance the source apportionment framework as an operational basis for national and local governments. © 2010 Elsevier Ltd. All rights reserved.

Precipitation climatology over India: validation with observations and reanalysis datasets and spatial trends

NASA Astrophysics Data System (ADS)

Kishore, P.; Jyothi, S.; Basha, Ghouse; Rao, S. V. B.; Rajeevan, M.; Velicogna, Isabella; Sutterley, Tyler C.

2016-01-01

Changing rainfall patterns have significant effect on water resources, agriculture output in many countries, especially the country like India where the economy depends on rain-fed agriculture. Rainfall over India has large spatial as well as temporal variability. To understand the variability in rainfall, spatial-temporal analyses of rainfall have been studied by using 107 (1901-2007) years of daily gridded India Meteorological Department (IMD) rainfall datasets. Further, the validation of IMD precipitation data is carried out with different observational and different reanalysis datasets during the period from 1989 to 2007. The Global Precipitation Climatology Project data shows similar features as that of IMD with high degree of comparison, whereas Asian Precipitation-Highly-Resolved Observational Data Integration Towards Evaluation data show similar features but with large differences, especially over northwest, west coast and western Himalayas. Spatially, large deviation is observed in the interior peninsula during the monsoon season with National Aeronautics Space Administration-Modern Era Retrospective-analysis for Research and Applications (NASA-MERRA), pre-monsoon with Japanese 25 years Re Analysis (JRA-25), and post-monsoon with climate forecast system reanalysis (CFSR) reanalysis datasets. Among the reanalysis datasets, European Centre for Medium-Range Weather Forecasts Interim Re-Analysis (ERA-Interim) shows good comparison followed by CFSR, NASA-MERRA, and JRA-25. Further, for the first time, with high resolution and long-term IMD data, the spatial distribution of trends is estimated using robust regression analysis technique on the annual and seasonal rainfall data with respect to different regions of India. Significant positive and negative trends are noticed in the whole time series of data during the monsoon season. The northeast and west coast of the Indian region shows significant positive trends and negative trends over western Himalayas and north central Indian region.

DVT Management and Outcome Trends, 2001 to 2014.

PubMed

Morillo, Raquel; Jiménez, David; Aibar, Miguel Ángel; Mastroiacovo, Daniela; Wells, Philip S; Sampériz, Ángel; Saraiva de Sousa, Marta; Muriel, Alfonso; Yusen, Roger D; Monreal, Manuel

2016-08-01

A comprehensive evaluation of temporal trends in the treatment of patients who have DVT may assist with identification of modifiable factors that contribute to short-term outcomes. We assessed temporal trends in length of hospital stay and use of pharmacological and interventional therapies among 26,695 adults with DVT enrolled in the Registro Informatizado de la Enfermedad TromboEmbólica registry between 2001 and 2014. We also examined temporal trends in risk-adjusted rates of all-cause, pulmonary embolism-related, and bleeding-related death to 30 days after diagnosis. The mean length of hospital stay decreased from 9.0 days in 2001 to 2005 to 7.6 days in 2010 to 2014 (P < .01). For initial DVT treatment, the use of low-molecular-weight heparin decreased from 98% to 90% (P < .01). Direct oral anticoagulants use increased from 0.5% in 2010 to 13.4% in 2014 (P < .001). Risk-adjusted rates of 30-day all-cause mortality decreased from 3.9% in 2001 to 2005 to 2.7% in 2010 to 2014 (adjusted rate ratio per year, 0.84; 95% CI, 0.74-0.96; P < .01). VTE-related mortality showed a nonstatistically significant downward trend (adjusted rate ratio per year, 0.70; 95% CI, 0.44-1.10; P = .13), whereas 30-day bleeding-related mortality significantly decreased from 0.5% in 2001 to 2005 to 0.1% in 2010-2014 (adjusted rate ratio per year, 0.55; 95% CI, 0.40-0.77; P < .01). This international registry-based temporal analysis identified reductions in length of stay for adults hospitalized for DVT. The study also found a decreasing trend in adjusted rates of all-cause and bleeding-related mortality. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Spatio-Temporal Change Modeling of Lulc: a Semantic Kriging Approach

NASA Astrophysics Data System (ADS)

Bhattacharjee, S.; Ghosh, S. K.

2015-07-01

Spatio-temporal land-use/ land-cover (LULC) change modeling is important to forecast the future LULC distribution, which may facilitate natural resource management, urban planning, etc. The spatio-temporal change in LULC trend often exhibits non-linear behavior, due to various dynamic factors, such as, human intervention (e.g., urbanization), environmental factors, etc. Hence, proper forecasting of LULC distribution should involve the study and trend modeling of historical data. Existing literatures have reported that the meteorological attributes (e.g., NDVI, LST, MSI), are semantically related to the terrain. Being influenced by the terrestrial dynamics, the temporal changes of these attributes depend on the LULC properties. Hence, incorporating meteorological knowledge into the temporal prediction process may help in developing an accurate forecasting model. This work attempts to study the change in inter-annual LULC pattern and the distribution of different meteorological attributes of a region in Kolkata (a metropolitan city in India) during the years 2000-2010 and forecast the future spread of LULC using semantic kriging (SemK) approach. A new variant of time-series SemK is proposed, namely Rev-SemKts to capture the multivariate semantic associations between different attributes. From empirical analysis, it may be observed that the augmentation of semantic knowledge in spatio-temporal modeling of meteorological attributes facilitate more precise forecasting of LULC pattern.

Sea-Level Trend Uncertainty With Pacific Climatic Variability and Temporally-Correlated Noise

NASA Astrophysics Data System (ADS)

Royston, Sam; Watson, Christopher S.; Legrésy, Benoît; King, Matt A.; Church, John A.; Bos, Machiel S.

2018-03-01

Recent studies have identified climatic drivers of the east-west see-saw of Pacific Ocean satellite altimetry era sea level trends and a number of sea-level trend and acceleration assessments attempt to account for this. We investigate the effect of Pacific climate variability, together with temporally-correlated noise, on linear trend error estimates and determine new time-of-emergence (ToE) estimates across the Indian and Pacific Oceans. Sea-level trend studies often advocate the use of auto-regressive (AR) noise models to adequately assess formal uncertainties, yet sea level often exhibits colored but non-AR(1) noise. Standard error estimates are over- or under-estimated by an AR(1) model for much of the Indo-Pacific sea level. Allowing for PDO and ENSO variability in the trend estimate only reduces standard errors across the tropics and we find noise characteristics are largely unaffected. Of importance for trend and acceleration detection studies, formal error estimates remain on average up to 1.6 times those from an AR(1) model for long-duration tide gauge data. There is an even chance that the observed trend from the satellite altimetry era exceeds the noise in patches of the tropical Pacific and Indian Oceans and the south-west and north-east Pacific gyres. By including climate indices in the trend analysis, the time it takes for the observed linear sea-level trend to emerge from the noise reduces by up to 2 decades.

Temporal and geographic patterns in population trends of brown-headed cowbirds

USGS Publications Warehouse

Peterjohn, B.G.; Sauer, J.R.; Schwarz, S.

2000-01-01

The temporal and geographic patterns in the population trends of Brown-headed Cowbirds are summarized from the North American Breeding Bird Survey. During 1966-1992, the survey-wide population declined significantly, a result of declining populations in the Eastern BBS Region, southern Great Plains, and the Pacific coast states. Increasing populations were most evident in the northern Great Plains. Cowbird populations were generally stable or increasing during 1966-1976, but their trends became more negative after 1976. The trends in cowbird populations were generally directly correlated with the trends of both host and nonhost species, suggesting that large-scale factors such as changing weather patterns, land use practices, or habitat availability were responsible for the observed temporal and geographic patterns in the trends of cowbirds and their hosts.

Data Flow Analysis and Visualization for Spatiotemporal Statistical Data without Trajectory Information.

PubMed

Kim, Seokyeon; Jeong, Seongmin; Woo, Insoo; Jang, Yun; Maciejewski, Ross; Ebert, David S

2018-03-01

Geographic visualization research has focused on a variety of techniques to represent and explore spatiotemporal data. The goal of those techniques is to enable users to explore events and interactions over space and time in order to facilitate the discovery of patterns, anomalies and relationships within the data. However, it is difficult to extract and visualize data flow patterns over time for non-directional statistical data without trajectory information. In this work, we develop a novel flow analysis technique to extract, represent, and analyze flow maps of non-directional spatiotemporal data unaccompanied by trajectory information. We estimate a continuous distribution of these events over space and time, and extract flow fields for spatial and temporal changes utilizing a gravity model. Then, we visualize the spatiotemporal patterns in the data by employing flow visualization techniques. The user is presented with temporal trends of geo-referenced discrete events on a map. As such, overall spatiotemporal data flow patterns help users analyze geo-referenced temporal events, such as disease outbreaks, crime patterns, etc. To validate our model, we discard the trajectory information in an origin-destination dataset and apply our technique to the data and compare the derived trajectories and the original. Finally, we present spatiotemporal trend analysis for statistical datasets including twitter data, maritime search and rescue events, and syndromic surveillance.

Estimates of spatial and temporal variation of energy crops biomass yields in the US

NASA Astrophysics Data System (ADS)

Song, Y.; Jain, A. K.; Landuyt, W.; Kheshgi, H. S.

2013-12-01

Perennial grasses, such as switchgrass (Panicum viragatum) and Miscanthus (Miscanthus x giganteus) have been identified for potential use as biomass feedstocks in the US. Current research on perennial grass biomass production has been evaluated on small-scale plots. However, the extent to which this potential can be realized at a landscape-scale will depend on the biophysical potential to grow these grasses with minimum possible amount of land that needs to be diverted from food to fuel production. To assess this potential three questions about the biomass yield for these grasses need to be answered: (1) how the yields for different grasses are varied spatially and temporally across the US; (2) whether the yields are temporally stable or not; and (3) how the spatial and temporal trends in yields of these perennial grasses are controlled by limiting factors, including soil type, water availability, climate, and crop varieties. To answer these questions, the growth processes of the perennial grasses are implemented into a coupled biophysical, physiological and biogeochemical model (ISAM). The model has been applied to quantitatively investigate the spatial and temporal trends in biomass yields for over the period 1980 -2010 in the US. The bioenergy grasses considered in this study include Miscanthus, Cave-in-Rock switchgrass and Alamo switchgrass. The effects of climate, soil and topography on the spatial and temporal trends of biomass yields are quantitatively analyzed using principal component analysis and GIS based geographically weighted regression. The spatial temporal trend results are evaluated further to classify each part of the US into four homogeneous potential yield zones: high and stable yield zone (HS), high but unstable yield zone (HU), low and stable yield zone (LS) and low but unstable yield zone (LU). Our preliminary results indicate that the yields for perennial grasses among different zones are strongly related to the different controlling factors. For example, the yield in HS zone is depended on soil and topography factors. However, the yields in HU zone are more controlled by climate factors, leading to a large uncertainty in yield potential of bioenergy grasses under future climate change.

Perspective: Crowd-based breath analysis: assessing behavior, activity, exposures, and emotional response of people in groups

EPA Science Inventory

A new concept for exhaled breath analysis has emerged wherein groups, or even crowds of people are simultaneously sampled in enclosed environments to detect overall trends in their activities and recent exposures. The basic idea is to correlate the temporal profile of known breat...

Methods for evaluating temporal trends in noise exposure

PubMed Central

Neitzel, RL; Galusha, D; Dixon-Ernst, C; Rabinowitz, PM

2014-01-01

Objective Hearing conservation programs have been mandatory in many US industries since 1983. Since then, three program elements (audiometric testing, hearing protection, and training) have been the focus of much research. By comparison, little has been done on noise exposure evaluation. Design and study sample Utilizing a large dataset (>10,000 measurements over 20 years) from eight facilities operated by a multinational aluminum manufacturing company, we evaluated several approaches to assessing temporal trends in Time Weighted Average (TWA) exposures and the fraction of measurements exceeding 85 dBA by facility, by exposure group within facility, and by individual worker within facility. Results Overall, exposures declined across locations over the study period. Several facilities demonstrated substantial reductions in exposure, and the results of mean noise levels and exceedance fractions generally showed good agreement. The results of analyses at the individual level diverged with analyses by facility and exposure group within facility, suggesting that individual-level analyses, while challenging, may provide important information not available from coarser levels of analysis. Conclusions Validated metrics are needed to allow for assessment of temporal trends in noise exposure. Such metrics will improve our ability to characterize, in a standardized manner, efforts to reduce noise-induced hearing loss. PMID:24564696

Methods for evaluating temporal trends in noise exposure.

PubMed

Neitzel, R L; Galusha, D; Dixon-Ernst, C; Rabinowitz, P M

2014-03-01

Hearing conservation programs have been mandatory in many US industries since 1983. Since then, three program elements (audiometric testing, hearing protection, and training) have been the focus of much research. By comparison, little has been done on noise exposure evaluation. Temporal trends in time weighted average (TWA) exposures and the fraction of measurements exceeding 85 dBA were evaluated by facility, by exposure group within facility, and by individual worker within facility. A large dataset (> 10 000 measurements over 20 years) from eight facilities operated by a multinational aluminum manufacturing company was studied. Overall, exposures declined across locations over the study period. Several facilities demonstrated substantial reductions in exposure, and the results of mean noise levels and exceedance fractions generally showed good agreement. The results of analyses at the individual level diverged with analyses by facility and exposure group within facility, suggesting that individual-level analyses, while challenging, may provide important information not available from coarser levels of analysis. Validated metrics are needed to allow for assessment of temporal trends in noise exposure. Such metrics will improve our ability to characterize, in a standardized manner, efforts to reduce noise-induced hearing loss.

Do pregnancy characteristics contribute to rising childhood cancer incidence rates in the United States?

PubMed

Kehm, Rebecca D; Osypuk, Theresa L; Poynter, Jenny N; Vock, David M; Spector, Logan G

2018-03-01

Since 1975, childhood cancer incidence rates have gradually increased in the United States; however, few studies have conducted analyses across time to unpack this temporal rise. The aim of this study was to test the hypothesis that increasing cancer incidence rates are due to secular trends in pregnancy characteristics that are established risk factors for childhood cancer incidence including older maternal age, higher birthweight, and lower birth order. We also considered temporal trends in sociodemographic characteristics including race/ethnicity and poverty. We conducted a time series county-level ecologic analysis using linked population-based data from Surveillance, Epidemiology, and End Results cancer registries (1975-2013), birth data from the National Center for Health Statistics (1970-2013), and sociodemographic data from the US Census (1970-2010). We estimated unadjusted and adjusted average annual percent changes (AAPCs) in incidence of combined (all diagnoses) and individual types of cancer among children, ages 0-4 years, from Poisson mixed models. There was a statistically significant unadjusted temporal rise in incidence of combined childhood cancers (AAPC = 0.71%; 95% CI = 0.55-0.86), acute lymphoblastic leukemia (0.78%; 0.49-1.07), acute myeloid leukemia (1.86%; 1.13-2.59), central nervous system tumors (1.31%; 0.94-1.67), and hepatoblastoma (2.70%; 1.68-3.72). Adjustment for county-level maternal age reduced estimated AAPCs between 8% (hepatoblastoma) and 55% (combined). However, adjustment for other county characteristics did not attenuate AAPCs, and AAPCs remained significantly above 0% in models fully adjusted for county-level characteristics. Although rising maternal age may account for some of the increase in childhood cancer incidence over time, other factors, not considered in this analysis, may also contribute to temporal trends. © 2017 Wiley Periodicals, Inc.

A Visual Analytics Approach for Station-Based Air Quality Data

PubMed Central

Du, Yi; Ma, Cuixia; Wu, Chao; Xu, Xiaowei; Guo, Yike; Zhou, Yuanchun; Li, Jianhui

2016-01-01

With the deployment of multi-modality and large-scale sensor networks for monitoring air quality, we are now able to collect large and multi-dimensional spatio-temporal datasets. For these sensed data, we present a comprehensive visual analysis approach for air quality analysis. This approach integrates several visual methods, such as map-based views, calendar views, and trends views, to assist the analysis. Among those visual methods, map-based visual methods are used to display the locations of interest, and the calendar and the trends views are used to discover the linear and periodical patterns. The system also provides various interaction tools to combine the map-based visualization, trends view, calendar view and multi-dimensional view. In addition, we propose a self-adaptive calendar-based controller that can flexibly adapt the changes of data size and granularity in trends view. Such a visual analytics system would facilitate big-data analysis in real applications, especially for decision making support. PMID:28029117

A Visual Analytics Approach for Station-Based Air Quality Data.

PubMed

Du, Yi; Ma, Cuixia; Wu, Chao; Xu, Xiaowei; Guo, Yike; Zhou, Yuanchun; Li, Jianhui

2016-12-24

With the deployment of multi-modality and large-scale sensor networks for monitoring air quality, we are now able to collect large and multi-dimensional spatio-temporal datasets. For these sensed data, we present a comprehensive visual analysis approach for air quality analysis. This approach integrates several visual methods, such as map-based views, calendar views, and trends views, to assist the analysis. Among those visual methods, map-based visual methods are used to display the locations of interest, and the calendar and the trends views are used to discover the linear and periodical patterns. The system also provides various interaction tools to combine the map-based visualization, trends view, calendar view and multi-dimensional view. In addition, we propose a self-adaptive calendar-based controller that can flexibly adapt the changes of data size and granularity in trends view. Such a visual analytics system would facilitate big-data analysis in real applications, especially for decision making support.

Temporal trends of selected agricultural chemicals in Iowa's groundwater, 1982-1995: Are things getting better?

USGS Publications Warehouse

Kolpin, D.W.; Sneck-Fahrer, D.; Hallberg, G.R.; Libra, R.D.

1997-01-01

Since 1982, the Iowa Groundwater Monitoring (IGWM) Program has been used to sample untreated groundwater from Iowa municipal wells for selected agricultural chemicals. This long-term database was used to determine if concentrations of select agricultural chemicals in groundwater have changed with time. Nitrate, alachlor [2-chloro-2′-6′-diethyl-N-(methoxymethyl)-acetanilide], atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), cyanazine [2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropionitrile)], and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] were selected for this temporal analysis of the data. Conclusive temporal changes in frequency of detection and median chemical concentrations were found only for atrazine (decrease) and metolachlor (increase). The greatest temporal chemical changes occurred in the shallowest wells and in alluvial aquifers—both relating to groups of wells generally having the youngest groundwater age. The temporal patterns found for atrazine and metolachlor are consistent with their patterns of chemical use and/or application rates and are suggestive of a causal relation. Only continued data collection, however, will indicate if the trends in chemical concentrations described here represent long-term temporal patterns or only short-term changes in groundwater. No definitive answers could be made in regards to the question of overall improvements in groundwater quality with respect to agricultural chemical contamination and time, due to the inherent problems with the simplistic measurement of overall severity (summation of alachlor + atrazine + cyanazine + metolachlor concentrations) examined for this study. To adequately determine if there is an actual decreasing trend in the overall severity of contamination (improving groundwater quality), the collection of additional water-chemistry data and the investigation of other measures of severity are needed.

Querying temporal clinical databases on granular trends.

PubMed

Combi, Carlo; Pozzi, Giuseppe; Rossato, Rosalba

2012-04-01

This paper focuses on the identification of temporal trends involving different granularities in clinical databases, where data are temporal in nature: for example, while follow-up visit data are usually stored at the granularity of working days, queries on these data could require to consider trends either at the granularity of months ("find patients who had an increase of systolic blood pressure within a single month") or at the granularity of weeks ("find patients who had steady states of diastolic blood pressure for more than 3 weeks"). Representing and reasoning properly on temporal clinical data at different granularities are important both to guarantee the efficacy and the quality of care processes and to detect emergency situations. Temporal sequences of data acquired during a care process provide a significant source of information not only to search for a particular value or an event at a specific time, but also to detect some clinically-relevant patterns for temporal data. We propose a general framework for the description and management of temporal trends by considering specific temporal features with respect to the chosen time granularity. Temporal aspects of data are considered within temporal relational databases, first formally by using a temporal extension of the relational calculus, and then by showing how to map these relational expressions to plain SQL queries. Throughout the paper we consider the clinical domain of hemodialysis, where several parameters are periodically sampled during every session. Copyright © 2011 Elsevier Inc. All rights reserved.

Frequency Analysis of Modis Ndvi Time Series for Determining Hotspot of Land Degradation in Mongolia

NASA Astrophysics Data System (ADS)

Nasanbat, E.; Sharav, S.; Sanjaa, T.; Lkhamjav, O.; Magsar, E.; Tuvdendorj, B.

2018-04-01

This study examines MODIS NDVI satellite imagery time series can be used to determine hotspot of land degradation area in whole Mongolia. The trend statistical analysis of Mann-Kendall was applied to a 16-year MODIS NDVI satellite imagery record, based on 16-day composited temporal data (from May to September) for growing seasons and from 2000 to 2016. We performed to frequency analysis that resulting NDVI residual trend pattern would enable successful determined of negative and positive changes in photo synthetically health vegetation. Our result showed that negative and positive values and generated a map of significant trends. Also, we examined long-term of meteorological parameters for the same period. The result showed positive and negative NDVI trends concurred with land cover types change representing an improve or a degrade in vegetation, respectively. Also, integrated the climate parameters which were precipitation and air temperature changes in the same time period seem to have had an affecting on huge NDVI trend area. The time series trend analysis approach applied successfully determined hotspot of an improvement and a degraded area due to land degradation and desertification.

Spatio-Temporal Trends of Oak Decline and Mortality under Periodic Regional Drought in the Ozark Highlands of Arkansas and Missouri

Treesearch

Zhaofei Fan; Xiuli Fan; Michael K. Crosby; W. Keith Moser; Hong He; Martin A. Spetich; Stephen R. Shifley

2012-01-01

At the forest landscape/region level, based on annual Forest Inventory and Analysis plot data from 1999 to 2010, oak decline and mortality trends for major oak species (groups) were examined in the Ozark Highlands of Arkansas and Missouri. Oak decline has elevated cumulative mortality of red oak species to between 11 and 15 percent in terms of relative density and...

A time series analysis of multiple ambient pollutants to investigate the underlying air pollution dynamics and interactions.

PubMed

Yu, Hwa-Lung; Lin, Yuan-Chien; Kuo, Yi-Ming

2015-09-01

Understanding the temporal dynamics and interactions of particulate matter (PM) concentration and composition is important for air quality control. This paper applied a dynamic factor analysis method (DFA) to reveal the underlying mechanisms of nonstationary variations in twelve ambient concentrations of aerosols and gaseous pollutants, and the associations with meteorological factors. This approach can consider the uncertainties and temporal dependences of time series data. The common trends of the yearlong and three selected diurnal variations were obtained to characterize the dominant processes occurring in general and specific scenarios in Taipei during 2009 (i.e., during Asian dust storm (ADS) events, rainfall, and under normal conditions). The results revealed the two distinct yearlong NOx transformation processes, and demonstrated that traffic emissions and photochemical reactions both critically influence diurnal variation, depending upon meteorological conditions. During an ADS event, transboundary transport and distinct weather conditions both influenced the temporal pattern of identified common trends. This study shows the DFA method can effectively extract meaningful latent processes of time series data and provide insights of the dominant associations and interactions in the complex air pollution processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Problems with the Fraser report Chapter 1: Pitfalls in BMI time trend analysis.

PubMed

Lo, Ernest

2014-11-05

The first chapter of the Fraser report "Obesity in Canada: Overstated Problems, Misguided Policy Solutions" presents a flawed and misleading analysis of BMI time trends. The objective of this commentary is to provide a tutorial on BMI time trend analysis through the examination of these flaws. Three issues are discussed: 1. Spotting regions of confidence interval overlap is a statistically flawed method of assessing trend; regression methods which measure the behaviour of the data as a whole are preferred. 2. Temporal stability in overweight (25≤BMI<30) prevalence must be interpreted in the context of the underlying population BMI distribution. 3. BMI is considered reliable for tracking population-level weight trends due to its high correlation with body fat percentage. BMI-defined obesity prevalence represents a conservative underestimate of the population at risk. The findings of the Fraser report Chapter 1 are either refuted or substantially mitigated once the above issues are accounted for, and we do not find that the 'Canadian situation largely lacks a disconcerting or negative trend', as claimed. It is hoped that this commentary will help guide public health professionals who need to interpret, or wish to perform their own, time trend analyses of BMI.

Spatio-Temporal b Value Trends For a PMMA-PMMA Frictional Interface

NASA Astrophysics Data System (ADS)

Parker, J.; Selvadurai, P. A.; Glaser, S. D.

2016-12-01

We develop a catalog of seismic events observed on a well-characterized PMMA-PMMA frictional interface to allow for an in depth study of spatio-temporal trends in along-fault b values. Recent studies of the 2009 L'Aquila [Gulia et al., GRL, 2016] and 2011 Tohoku-oki [Tormann et al., Nature Geo., 2015] events have found significant decrease in b values near the epicenters in the months leading up to rupture. Here, a fault is experimentally modeled using two Poly(methyl methacrylate) samples in a direct shear configuration. The initial, non-uniform distribution of asperities along the frictional interface was measured using a pressure sensitive film. Prior to a stick-slip event, localized seismicity was captured using 16 acoustic emission (AE) sensors, which provide the catalog events and b value analysis. We observe similar decreasing trends in b values prior to failure as observed in nature. We discuss the spatio-temporal variations in b values with respect to a slowly expanding shear rupture captured using dense `along-strike' arrays of 9 slip sensors and 24 strain gauges. The rate at which the shear rupture moved along the interface depended on the shear strength heterogeneity characterized by the non-uniform distribution of asperities. In the latter stages of nucleation, b values decrease primarily in a region with larger and more densely distributed asperities. The combined analysis will help confirm recent field observations and provide insight into the mechanics of foreshock sequences leading to earthquake rupture.

Trends and determinants of discretionary salt use: National Health and Nutrition Examination Survey, 2003-2012

USDA-ARS?s Scientific Manuscript database

The objective of this study was to examine the recent temporal trends and current determinants of discretionary salt use in the United States. We used data from the National Health and Nutrition Examination Survey (NHANES), 2003-2012. We used multiple logistic regression to assess temporal trends ...

Space-time patterns of trends in stratospheric constituents derived from UARS measurements

NASA Astrophysics Data System (ADS)

Randel, William J.; Wu, Fei; Russell, James M.; Waters, Joe

1999-02-01

The spatial and temporal behavior of low-frequency changes (trends) in stratospheric constituents measured by instruments on the Upper Atmosphere Research Satellite (UARS) during 1991-98 is investigated. The data include CH4, H2O, HF, HCl, O3, and NO2 from the Halogen Occultation Experiment (HALOE), and O3, ClO, and HNO3 from the Microwave Limb Sounder (MLS). Time series of global anomalies are analyzed by linear regression and empirical orthogonal function analysis. Each of the constituents show significant linear trends over at least some region of the stratosphere, and the spatial patterns exhibit coupling between the different species. Several of the constituents (namely CH4, H2O, HF, HCl, O3, and NO2) exhibit a temporal change in trend rates, with strong changes prior to 1996 and weaker (or reversed) trends thereafter. Positive trends are observed in upper stratospheric ClO, with a percentage rate during 1993-97 consistent with stratospheric HCl increases and with tropospheric chlorine emission rates. Significant negative trends in ozone in the tropical middle stratosphere are found in both HALOE and MLS data during 1993-97, together with positive trends in the tropics near 25 km. These trends are very different from the decadal-scale ozone trends observed since 1979, and this demonstrates the variability of trends calculated over short time periods. Positive trends in NO2 are found in the tropical middle stratosphere, and spatial coincidence to the observed ozone decreases suggests the ozone is responding to the NO2 increase. Significant negative trends in HNO3 are found in the lower stratosphere of both hemispheres. These coupled signatures offer a fingerprint of chemical evolution in the stratosphere for the UARS time frame.

Spatio-temporal analysis of recent groundwater-level trends in the Red River Delta, Vietnam

NASA Astrophysics Data System (ADS)

Bui, Duong Du; Kawamura, Akira; Tong, Thanh Ngoc; Amaguchi, Hideo; Nakagawa, Naoko

2012-12-01

A groundwater-monitoring network has been in operation in the Red River Delta, Vietnam, since 1995. Trends in groundwater level (1995-2009) in 57 wells in the Holocene unconfined aquifer and 63 wells in the Pleistocene confined aquifer were determined by applying the non-parametric Mann-Kendall trend test and Sen's slope estimator. At each well, 17 time series (e.g. annual, seasonal, monthly), computed from the original data, were analyzed. Analysis of the annual groundwater-level means revealed that 35 % of the wells in the unconfined aquifer showed downward trends, while about 21 % showed upward trends. On the other hand, confined-aquifer groundwater levels experienced downward trends in almost all locations. Spatial distributions of trends indicated that the strongly declining trends (>0.3 m/year) were mainly found in urban areas around Hanoi where there is intensive abstraction of groundwater. Although the trend results for most of the 17 time series at a given well were quite similar, different trend patterns were detected in several. The findings reflect unsustainable groundwater development and the importance of maintaining groundwater monitoring and a database in the Delta, particularly in urban areas.

Temporal trends and factors associated with diabetes mellitus among patients hospitalized with heart failure: Findings from Get With The Guidelines-Heart Failure registry.

PubMed

Echouffo-Tcheugui, Justin B; Xu, Haolin; DeVore, Adam D; Schulte, Phillip J; Butler, Javed; Yancy, Clyde W; Bhatt, Deepak L; Hernandez, Adrian F; Heidenreich, Paul A; Fonarow, Gregg C

2016-12-01

The contribution of diabetes to the burden of heart failure (HF) remains largely undescribed. Assessing diabetes temporal trends among US patients hospitalized with HF and their relation with quality measures in real-world practice can help to define this burden. Using data from the Get With the Guidelines-Heart Failure registry, we assessed temporal trends in diabetes prevalence among patients with HF and in subgroups with reduced ejection fraction (HFrEF; EF < 40%), borderline EF (HFbEF; 40%≤EF <50%), or preserved EF (HFpEF; EF ≥ 50%), hospitalized between 2005 and 2015. Logistic regression was used to assess whether in-hospital outcomes and HF quality of care were related to trends. Among 364,480 HF hospitalizations, 160,171 had diabetes (44.0% overall, 41.8% in HFrEF, 46.7% in HFbEF, 45.5% in HFpEF). There was a temporal increase in diabetes frequency in HF patients (43.2%-45.8%; P trend <.0001), including among those with HFrEF (42.0%-43.6%; P trend <.0001), HFbEF (46.0%-49.2%; P trend <.0001), or HFpEF (43.6%-46.8%, P trend <.0001). Diabetic patients had a longer hospital stay (adjusted odds ratio 1.14, 95% CI 1.12-1.16), but lower in-hospital mortality (adjusted odds ratio 0.93 [0.89-0.97]) compared with those without diabetes, with limited differences in quality measures. Temporal trends in diabetes were not associated with in-hospital mortality or length of stay. There were no temporal interactions of most HF quality measures with diabetes status. Approximately 44% of hospitalized HF patients have diabetes, and this proportion has been increasing over the past 10years, particularly among those patients with new-onset HFpEF. Copyright © 2016 Elsevier Inc. All rights reserved.

Identify temporal trend of air temperature and its impact on forest stream flow in Lower Mississippi River Alluvial Valley using wavelet analysis

USDA-ARS?s Scientific Manuscript database

Characterization of stream flow is essential to water resource management, water supply planning, environmental protection, and ecological restoration; while climate change can exacerbate stream flow and add instability to the flow. In this study, the wavelet analysis technique was employed to asse...

Trends in the temporal distribution of park use

Treesearch

Robert E. Manning; Paula L. Cormier

1980-01-01

The purpose of this paper is to examine trends in the temporal distribution of park use. Plots of daily attendance data trace changes in temporal use distributions over time. A use concentration index quantifies and reduces to a single numerical indicator the degree of unevenness of recreation attendance data. The percent of total annual use accounted for by selected...

Temporal Structure of Support Surface Translations Drive the Temporal Structure of Postural Control During Standing

PubMed Central

Rand, Troy J.; Myers, Sara A.; Kyvelidou, Anastasia; Mukherjee, Mukul

2015-01-01

A healthy biological system is characterized by a temporal structure that exhibits fractal properties and is highly complex. Unhealthy systems demonstrate lowered complexity and either greater or less predictability in the temporal structure of a time series. The purpose of this research was to determine if support surface translations with different temporal structures would affect the temporal structure of the center of pressure (COP) signal. Eight healthy young participants stood on a force platform that was translated in the anteroposterior direction for input conditions of varying complexity: white noise, pink noise, brown noise, and sine wave. Detrended fluctuation analysis was used to characterize the long-range correlations of the COP time series in the AP direction. Repeated measures ANOVA revealed differences among conditions (P < .001). The less complex support surface translations resulted in a less complex COP compared to normal standing. A quadratic trend analysis demonstrated an inverted-u shape across an increasing order of predictability of the conditions (P < .001). The ability to influence the complexity of postural control through support surface translations can have important implications for rehabilitation. PMID:25994281

Temporal Topic Modeling to Assess Associations between News Trends and Infectious Disease Outbreaks.

PubMed

Ghosh, Saurav; Chakraborty, Prithwish; Nsoesie, Elaine O; Cohn, Emily; Mekaru, Sumiko R; Brownstein, John S; Ramakrishnan, Naren

2017-01-19

In retrospective assessments, internet news reports have been shown to capture early reports of unknown infectious disease transmission prior to official laboratory confirmation. In general, media interest and reporting peaks and wanes during the course of an outbreak. In this study, we quantify the extent to which media interest during infectious disease outbreaks is indicative of trends of reported incidence. We introduce an approach that uses supervised temporal topic models to transform large corpora of news articles into temporal topic trends. The key advantages of this approach include: applicability to a wide range of diseases and ability to capture disease dynamics, including seasonality, abrupt peaks and troughs. We evaluated the method using data from multiple infectious disease outbreaks reported in the United States of America (U.S.), China, and India. We demonstrate that temporal topic trends extracted from disease-related news reports successfully capture the dynamics of multiple outbreaks such as whooping cough in U.S. (2012), dengue outbreaks in India (2013) and China (2014). Our observations also suggest that, when news coverage is uniform, efficient modeling of temporal topic trends using time-series regression techniques can estimate disease case counts with increased precision before official reports by health organizations.

Temporal Topic Modeling to Assess Associations between News Trends and Infectious Disease Outbreaks

NASA Astrophysics Data System (ADS)

Ghosh, Saurav; Chakraborty, Prithwish; Nsoesie, Elaine O.; Cohn, Emily; Mekaru, Sumiko R.; Brownstein, John S.; Ramakrishnan, Naren

2017-01-01

In retrospective assessments, internet news reports have been shown to capture early reports of unknown infectious disease transmission prior to official laboratory confirmation. In general, media interest and reporting peaks and wanes during the course of an outbreak. In this study, we quantify the extent to which media interest during infectious disease outbreaks is indicative of trends of reported incidence. We introduce an approach that uses supervised temporal topic models to transform large corpora of news articles into temporal topic trends. The key advantages of this approach include: applicability to a wide range of diseases and ability to capture disease dynamics, including seasonality, abrupt peaks and troughs. We evaluated the method using data from multiple infectious disease outbreaks reported in the United States of America (U.S.), China, and India. We demonstrate that temporal topic trends extracted from disease-related news reports successfully capture the dynamics of multiple outbreaks such as whooping cough in U.S. (2012), dengue outbreaks in India (2013) and China (2014). Our observations also suggest that, when news coverage is uniform, efficient modeling of temporal topic trends using time-series regression techniques can estimate disease case counts with increased precision before official reports by health organizations.

Temporal Topic Modeling to Assess Associations between News Trends and Infectious Disease Outbreaks

PubMed Central

Ghosh, Saurav; Chakraborty, Prithwish; Nsoesie, Elaine O.; Cohn, Emily; Mekaru, Sumiko R.; Brownstein, John S.; Ramakrishnan, Naren

2017-01-01

In retrospective assessments, internet news reports have been shown to capture early reports of unknown infectious disease transmission prior to official laboratory confirmation. In general, media interest and reporting peaks and wanes during the course of an outbreak. In this study, we quantify the extent to which media interest during infectious disease outbreaks is indicative of trends of reported incidence. We introduce an approach that uses supervised temporal topic models to transform large corpora of news articles into temporal topic trends. The key advantages of this approach include: applicability to a wide range of diseases and ability to capture disease dynamics, including seasonality, abrupt peaks and troughs. We evaluated the method using data from multiple infectious disease outbreaks reported in the United States of America (U.S.), China, and India. We demonstrate that temporal topic trends extracted from disease-related news reports successfully capture the dynamics of multiple outbreaks such as whooping cough in U.S. (2012), dengue outbreaks in India (2013) and China (2014). Our observations also suggest that, when news coverage is uniform, efficient modeling of temporal topic trends using time-series regression techniques can estimate disease case counts with increased precision before official reports by health organizations. PMID:28102319

Visualizing geographic and temporal trends in rotavirus activity in the United States, 1991 to 1996. National Respiratory and Enteric Virus Surveillance System Collaborating Laboratories.

PubMed

Török, T J; Kilgore, P E; Clarke, M J; Holman, R C; Bresee, J S; Glass, R I

1997-10-01

Rotavirus is the leading cause of severe pediatric gastroenteritis worldwide. A vaccine may soon be licensed for use in the United States to prevent this disease. To characterize US geographic and temporal trends in rotavirus activity, we made contour maps showing the timing of peak rotavirus activity. From July, 1991, through June, 1996, 79 laboratories participating in the National Respiratory and Enteric Virus Surveillance System reported on a weekly basis the number of stool specimens that tested positive for rotavirus. The peak weeks in rotavirus detections from each laboratory were mapped using kriging, a modeling technique originally developed for geostatistics. During the 5-year period 118,716 fecal specimens were examined, of which 27,616 (23%) were positive for rotavirus. Timing of rotavirus activity varied by geographic location in a characteristic pattern in which peak activity occurred first in the Southwest from October through December and last in the Northeast in April or May. The Northwest exhibited considerable year-to-year variability (range, December to May) in the timing of peak activity, whereas the temporal pattern in the remainder of the contiguous 48 states was relatively constant. Kriging is a useful method for visualizing geographic and temporal trends in rotavirus activity in the United States. This analysis confirmed trends reported in previous years, and it also identified unexpected variability in the timing of peak rotavirus activity in the Northwest. The causes of the seasonal differences in rotavirus activity by region are unknown. Tracking of laboratory detections of rotavirus may provide an effective surveillance tool to assess the impact of a rotavirus vaccination campaign in the United States.

Spatial and Temporal Inter-Relationships between Anomalies and Trends of Temperature, Moisture, Cloud Cover, and OLR as Observed by AIRS/AMSU on Aqua

NASA Technical Reports Server (NTRS)

Susskind, Joel

2008-01-01

AIRS/AMSU is the advanced IR/MW atmospheric sounding system launched on EOS Aqua in May 2002. Products derived from AIRS/AMSU by the AIRS Science Team include surface skin temperature and atmospheric temperature profiles; atmospheric humidity profiles, fractional cloud cover and cloud top pressure, and OLR. Products covering the period September 2002 through the present have been derived from AIRS/AMSU using the AIRS Science Team Version 5 retrieval algorithm. In this paper, we will show results covering the time period September 2006 - November 2008. This time period is marked by a substantial warming trend of Northern Hemisphere Extratropical land surface skin temperatures, as well as pronounced El Nino - La Nina episodes. These both influence the spatial and temporal anomaly patterns of atmospheric temperature and moisture profiles, as well as of cloud cover and Clear sky and All Sky OLR. The relationships between temporal and spatial anomalies of these parameters over this time period, as determined from AIRS/AMSU observations, will be shown, with particular emphasis on which contribute significantly to OLR anomalies in each of the tropics and extra-tropics. Results will also be shown to validate the anomalies and trends of temperature profiles and OLR as determined from analysis of AIRS/AMSU data. Global and regional trends during the 6 1/3 year period are not necessarily indicative of what has happened in the past, or what may happen in the future. Nevertheless, the inter-relationships of spatial and temporal anomalies of atmospheric geophysical parameters with those of surface skin temperature are indicative of climate processes, and can be used to test the performance of climate models when driven by changes in surface temperatures.

Spatial and Temporal Inter-Relationship between Anomalies and Trends of Temperature, Moisture, Cloud Cover and OLR as Observed by AIRS/AMSU on Aqua

NASA Technical Reports Server (NTRS)

Susskind, Joel; Molnar, Gyula

2009-01-01

AIRS/AMSU is the advanced IR/MW atmospheric sounding system launched on EOS Aqua in May 2002. Products derived from AIRS/AMSU by the AIRS Science Team include surface skin temperature and atmospheric temperature profiled; atmospheric humidity profiles, fractional cloud clover and cloud top pressure, and OLR. Products covering the period September 2002 through the present have been derived from AIRS/AMSU using the AIRS Science Team Version 5 retrieval algorithm. In this paper, we will show results covering the time period September 2006 - November 2008. This time period is marked by a substantial warming trend of Northern Hemisphere Extra-tropical land surface skin temperatures, as well as pronounced El Nino - La Nina episodes. These both influence the spatial and temporal anomaly patterns of atmospheric temperature and moisture profiles, as well as of cloud cover and Clear Sky and All Sky OLR. The relationships between temporal and spatial anomalies of these parameters over this time period, as determined from AIRS/AMSU observations, will be shown with particular emphasis on which contribute significantly to OLR anomalies in each of the tropics and extra-tropics. Results will also be shown to evaluate the anomalies and trends of temperature profiles and OLR as determined from analysis of AIRS/AMSU data. Global and regional trends during the 6 1/3 year time period are not necessarily indicative of what has happened in the past, or what may happen in the future. Nevertheless, the inter-relationships of spatial and temporal anomalies of atmospheric geophysical parameters with those of surface skin temperature are indicative of climate processes, and can be used to test the performance of climate models when driven by changes in surface temperatures.

Up-Regulation of Autophagy in Small Intestine Paneth Cells in Response to Total-Body gamma-Irradiation

DTIC Science & Technology

2009-01-01

standard error of the mean (SEM). Analysis of variance procedures with Tukey post hoc correction examined the existence and nature of temporal trends ...apoptosis. Cell 2006;126:121–134. 20. Yorimitsu T, Klionsky DJ. Eating the enoplasmic reticulum: quality control by autophagy. Trends Cell Biol 2007;17...oxide signaling to iron- regulatory protein: direct control of ferritin mRNA translation and transferrin receptor mRNA stability in transfected

Spatial-temporal cluster analysis of mortality from road traffic injuries using geographic information systems in West of Iran during 2009-2014.

PubMed

Zangeneh, Alireza; Najafi, Farid; Karimi, Saeed; Saeidi, Shahram; Izadi, Neda

2018-04-01

Road traffic injuries (RTIs) are considered as one of the most important health problems endangering people's life. The examination of the geographical distribution of RTIs could help policymakers in better planning to reduce RTIs. This study, therefore, aimed to determine the spatial-temporal clustering of mortality from RTIs in West of Iran. Deaths from RTIs, registered in Forensic Medicine Organization of Kermanshah province over a period of six years (2009-2014), were used. Using negative binomial regression, the mortality trend was investigated. In order to investigate the spatial distribution of RTIs, we used ArcGIS. (Version 10.3). The median age of the 3231 people died in RTIs was 37 (IQR = 31) year, 78.4% were male. The 6-year average mortality rate from RTIs was 27.8/100,000 deaths, and the average rate had a declining trend. The dispersion of RTIs showed that most deaths occurred in Kermanshah, Islamabad, Bisotun, and Harsin road axes, respectively. The mean center of all deaths from RTIs occurred in Kermanshah province, the central area of Kermanshah district. The spatial trend of such deaths has moved to the northeast-southwest, and such deaths were geographically centralized. Results of Moran's I with respect to cluster analysis also indicated positive spatial autocorrelations. The results showed that the mortality rate from RTIs, despite the decline in recent years, is still high when compared with other countries. The clustering of accidents raises the concern that road infrastructure in certain locations may also be a factor. Regarding the results related to the temporal analysis, it is suggested that the enforcement of traffic rules be stricter at rush hours. Copyright © 2018 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Spatio-temporal atmospheric circulation variability around the Antarctic Peninsula based on hemispheric circulation modes and weather types

NASA Astrophysics Data System (ADS)

Wachter, Paul; Beck, Christoph; Philipp, Andreas; Jacobeit, Jucundus; Höppner, Kathrin

2017-04-01

Large parts of the Polar Regions are affected by a warming trend associated with substantial changes in the cryosphere. In Antarctica this positive trend pattern is most dominant in the western part of the continent and on the Antarctic Peninsula (AP). An important driving mechanism of temperature variability and trends in this region is the atmospheric circulation. Changes in atmospheric circulation modes and frequencies of circulation types have major impacts on temperature characteristics at a certain station or region. We present results of a statistical downscaling study focused on AP temperature variability showing both results of large-scale atmospheric circulation modes and regional weather type classifications derived from monthly and daily gridded reanalysis data sets. In order to investigate spatial trends and variabilities of the Southern Annular Mode (SAM), we analyze spatio-temporally resolved SAM-pattern maps from 1979 to 2015. First results show dominant multi-annual to decadal pattern variabilities which can be directly linked to temperature variabilities at the Antarctic Peninsula. A sub-continental to regional view on the influence of atmospheric circulation on AP temperature variability is given by the analysis of weather type classifications (WTC). With this analysis we identify significant changes in the frequency of occurrence of highly temperature-relevant circulation patterns. The investigated characteristics of weather type frequencies can also be related to the identified changes of the SAM.

Intelligent trend analysis for a solar thermal energy collector field

NASA Astrophysics Data System (ADS)

Juuso, E. K.

2018-03-01

Solar thermal power plants collect available solar energy in a usable form at a temperature range which is adapted to the irradiation levels and seasonal variations. Solar energy can be collected only when the irradiation is high enough to produce the required temperatures. During the operation, a trade-off of the temperature and the flow is needed to achieve a good level for the collected power. The scaling approach brings temporal analysis to all measurements and features: trend indices are calculated by comparing the averages in the long and short time windows, a weighted sum of the trend index and its derivative detects the trend episodes and severity of the trend is estimated by including also the variable level in the sum. The trend index, trend episodes and especially, the deviation index reveal early evolving changes in the operating conditions, including cloudiness and load disturbances. The solution is highly compact: all variables, features and indices are transformed to the range [-2, 2] and represented in natural language which is important in integrating data-driven solutions with domain expertise. The special situations detected during the test campaigns are explained well.

Assessing Climate Risk on Agricultural Production: Insights Using Retrospective Analysis of Crop Insurance and Climatic Trends

NASA Astrophysics Data System (ADS)

Reyes, J. J.; Elias, E.; Eischens, A.; Shilts, M.; Rango, A.; Steele, R.

2017-12-01

The collaborative synthesis of existing datasets, such as long-term climate observations and farmers' crop insurance payments, can increase their overall collective value and societal application. The U.S. Department of Agriculture (USDA) Climate Hubs were created to develop and deliver science-based information and technologies to agricultural and natural resource managers to enable climate-informed decision-making. As part of this mission, Hubs work across USDA and other climate service agencies to synthesize existing information. The USDA Risk Management Agency (RMA) is responsible for overseeing the Federal crop insurance program which currently insures over $100 billion in crops annually. RMA hosts data describing the cause for loss (e.g. drought, wind, irrigation failure) and indemnity amount (i.e. total cost of loss) at multiple spatio-temporal scales (i.e. state, county, year, month). The objective of this paper is to link climate information with indemnities, and their associated cause of loss, to assess climate risk on agricultural production and provide regionally-relevant information to stakeholders to promote resilient working landscapes. We performed a retrospective trend analysis at the state-level for the American Southwest (SW). First, we assessed indemnity-only trends by cause of loss and crop type at varying temporal scales. Historical monthly weather data (i.e. precipitation and temperature) and long-term drought indices (e.g. Palmer Drought Severity Index) were then linked with indemnities and grouped by different causes of loss. Climatological ranks were used to integrate historical comparative intensity of acute and long-term climatic events. Heat and drought as causes of loss were most correlated with temperature and drought indicators, respectively. Across all SW states increasing indemnities were correlated with warmer conditions. Multiple statistical trend analyses suggest a framework is necessary to appropriately measure the biophysical signals in crop insurance trends taking into account spatio-temporal characteristics. Based on stakeholder feedback, we also developed a web-based information browser to visualize and assess indemnity trends providing useful and usable knowledge to support informed land management decisions and ecosystem resilience.

Spatial and Temporal Patterns In Ecohydrological Separation

NASA Astrophysics Data System (ADS)

Jarvis, S. K.; Barnard, H. R.; Singha, K.; Harmon, R. E.; Szutu, D.

2017-12-01

The model of ecohydrological separation suggests that trees source water from a different subsurface pool than what is contributing to stream flow during dry periods, however diel fluctuations in stream flow and transpiration are tightly coupled. To better understand the mechanism of this coupling, this study examines spatiotemporal patterns in water isotopic relationships between tree, soil, and stream water. Preliminary analysis of data collected in 2015 show a trend in δ18O enrichment in xylem water, suggesting an increased reliance on enriched soil water not flowing to the stream as the growing season progresses, while xylem samples from 2016, a particularly wet year, do not have this trend. Variations in these temporal trends are explored with regard to distance from stream, aspect of hillslope, position in the watershed, size of the tree, and soil depth. Additionally, a near-stream site is examined at high resolution using water isotope data, sap flow, and electrical resistivity surveying to examine soil moisture and water use patterns across the riparian-hillslope transition.

Study of temporal trends in mercury concentrations in the primary flight feathers of Strix aluco.

PubMed

Varela, Z; García-Seoane, R; Fernández, J A; Carballeira, A; Aboal, J R

2016-08-01

Temporal trends in Hg concentrations were determined in the primary flight feathers of 146 specimens of Strix aluco which had died in various Wildlife Recovery Centres in Galicia (NW Spain) between 1997 and 2014. The aim of the study was to determine whether standardization of a primary flight feather (or feathers) in this species is essential for identifying temporal trends in Hg concentrations. For this purpose, we had to first standardize the feather(s) analyzed to enable comparison of the levels of Hg detected in different feathers. The results show a high degree of both inter and intra-individual variability but despite that, it was possible to identify P5 as the most representative feather taking into account the amount of metal excreted in each feather and the intra-individual variability: its median was 133ng, which represents 15% (from 7% to 15%) of the total Hg present in all the primary feathers. However, this "standard feather" did not reveal any temporal trend in Hg concentrations for the study period. This lack of trend was found irrespective of the feather considered and it is expected that detection of any existing trend would also not depend on the feather considered. We conclude that use of any particular feather is not essential for identifying temporal trends in Hg concentrations, because the pattern will be identified regardless of the feather selected. Copyright © 2016 Elsevier Inc. All rights reserved.

Temporal abstraction for the analysis of intensive care information

NASA Astrophysics Data System (ADS)

Hadad, Alejandro J.; Evin, Diego A.; Drozdowicz, Bartolomé; Chiotti, Omar

2007-11-01

This paper proposes a scheme for the analysis of time-stamped series data from multiple monitoring devices of intensive care units, using Temporal Abstraction concepts. This scheme is oriented to obtain a description of the patient state evolution in an unsupervised way. The case of study is based on a dataset clinically classified with Pulmonary Edema. For this dataset a trends based Temporal Abstraction mechanism is proposed, by means of a Behaviours Base of time-stamped series and then used in a classification step. Combining this approach with the introduction of expert knowledge, using Fuzzy Logic, and multivariate analysis by means of Self-Organizing Maps, a states characterization model is obtained. This model is feasible of being extended to different patients groups and states. The proposed scheme allows to obtain intermediate states descriptions through which it is passing the patient and that could be used to anticipate alert situations.

Sequential change detection and monitoring of temporal trends in random-effects meta-analysis.

PubMed

Dogo, Samson Henry; Clark, Allan; Kulinskaya, Elena

2017-06-01

Temporal changes in magnitude of effect sizes reported in many areas of research are a threat to the credibility of the results and conclusions of meta-analysis. Numerous sequential methods for meta-analysis have been proposed to detect changes and monitor trends in effect sizes so that meta-analysis can be updated when necessary and interpreted based on the time it was conducted. The difficulties of sequential meta-analysis under the random-effects model are caused by dependencies in increments introduced by the estimation of the heterogeneity parameter τ 2 . In this paper, we propose the use of a retrospective cumulative sum (CUSUM)-type test with bootstrap critical values. This method allows retrospective analysis of the past trajectory of cumulative effects in random-effects meta-analysis and its visualization on a chart similar to CUSUM chart. Simulation results show that the new method demonstrates good control of Type I error regardless of the number or size of the studies and the amount of heterogeneity. Application of the new method is illustrated on two examples of medical meta-analyses. © 2016 The Authors. Research Synthesis Methods published by John Wiley & Sons Ltd. © 2016 The Authors. Research Synthesis Methods published by John Wiley & Sons Ltd.

SOMA: A Proposed Framework for Trend Mining in Large UK Diabetic Retinopathy Temporal Databases

NASA Astrophysics Data System (ADS)

Somaraki, Vassiliki; Harding, Simon; Broadbent, Deborah; Coenen, Frans

In this paper, we present SOMA, a new trend mining framework; and Aretaeus, the associated trend mining algorithm. The proposed framework is able to detect different kinds of trends within longitudinal datasets. The prototype trends are defined mathematically so that they can be mapped onto the temporal patterns. Trends are defined and generated in terms of the frequency of occurrence of pattern changes over time. To evaluate the proposed framework the process was applied to a large collection of medical records, forming part of the diabetic retinopathy screening programme at the Royal Liverpool University Hospital.

Trend analysis of selected water-quality constituents in the Verde River Basin, central Arizona

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldys, S.

1990-01-01

Temporal trends of eight water quality constituents at six data collection sites in the Verde River basin in central Arizona were investigated using seasonal Kendall tau and ordinary least-squares regression methods of analysis. The constituents are dissolved solids, dissolved sulfate, dissolved arsenic, total phosphorus, pH, total nitrite plus nitrate-nitrogen, dissolved iron, and fecal coliform bacteria. Increasing trends with time in dissolved-solids concentrations of 7 to 8 mg/L/yr at Verde River near Camp Verde were found at significant level. An increasing trend in dissolved-sulfate concentrations of 3.59 mg/L/yr was also found at Verde River near Camp Verde, although at nonsignificant levels.more » Statistically significant decreasing trends with time in dissolved-solids and dissolved-sulfate concentrations were found at Verde River above Horseshoe Reservoir, which is downstream from Verde River near Camp Verde. Observed trends in the other constituents do not indicate the emergence of water quality problems in the Verde River basin. Analysis of the eight water quality constituents generally indicate nonvarying concentration levels after adjustment for seasonality and streamflow were made.« less

Variability in solar radiation and temperature explains observed patterns and trends in tree growth rates across four tropical forests.

PubMed

Dong, Shirley Xiaobi; Davies, Stuart J; Ashton, Peter S; Bunyavejchewin, Sarayudh; Supardi, M N Nur; Kassim, Abd Rahman; Tan, Sylvester; Moorcroft, Paul R

2012-10-07

The response of tropical forests to global climate variability and change remains poorly understood. Results from long-term studies of permanent forest plots have reported different, and in some cases opposing trends in tropical forest dynamics. In this study, we examined changes in tree growth rates at four long-term permanent tropical forest research plots in relation to variation in solar radiation, temperature and precipitation. Temporal variation in the stand-level growth rates measured at five-year intervals was found to be positively correlated with variation in incoming solar radiation and negatively related to temporal variation in night-time temperatures. Taken alone, neither solar radiation variability nor the effects of night-time temperatures can account for the observed temporal variation in tree growth rates across sites, but when considered together, these two climate variables account for most of the observed temporal variability in tree growth rates. Further analysis indicates that the stand-level response is primarily driven by the responses of smaller-sized trees (less than 20 cm in diameter). The combined temperature and radiation responses identified in this study provide a potential explanation for the conflicting patterns in tree growth rates found in previous studies.

Temporal factors in violence related injuries--An 11 year trend analysis of violence-related injuries from a Swiss Emergency Department.

PubMed

Clément, Nicolas; Businger, Adrian; Lindner, Gregor; Müller, Wolfgang P; Hüsler, J; Zimmermann, Heinz; Exadaktylos, Aristomenis K

2012-12-01

Injury from interpersonal violence is a major social and medical problem in the industrialized world. Little is known about the trends in prevalence and injury pattern or about the demographic characteristics of the patients involved. In this retrospective analysis, we screened the database of the Emergency Department of a large university hospital for all patients who were admitted for injuries due to interpersonal violence over an 11 year period. For all patients identified, we gathered data on age, country of origin, quality of injury, and hospitalization or outpatient management. A trend analysis was performed using Kendall's tau-b correlation coefficients for regression analysis. The overall number of patients admitted to our Emergency Department remained stable over the study period. Non-Swiss nationals were overrepresented in comparison to the demographics of the region where the study was conducted. There was a trend toward a more severe pattern of injury, such as an increase in the number of severe head injuries. Although the overall number of patients remained stable over the study period, there was an alarming trend toward a more severe pattern of injury, expressed by an increase in severe head traumas.

Differential patterns, trends and hotspots of road traffic injuries on different road networks in Vellore district, southern India.

PubMed

Mohan, Venkata Raghava; Sarkar, Rajiv; Abraham, Vinod Joseph; Balraj, Vinohar; Naumova, Elena N

2015-03-01

To describe spatial and temporal profiles of Road Traffic Injuries (RTIs) on different road networks in Vellore district of southern India. Using the information in the police maintained First Information Reports (FIRs), daily time series of RTI counts were created and temporal characteristics were analysed with respect to the vehicle, road types and time of the day for the period January 2005 to May 2007. Daily incidence and trend of RTIs were estimated using a Poisson regression analysis. Of the reported 3262 RTIs, 52% had occurred on the National Highway (NH). The overall RTI rate on the NH was 8.8/100 000 vehicles per day with significantly higher pedestrian involvement. The mean numbers of RTIs were significantly higher on weekends. Thirteen percentage of all RTIs were associated with fatalities. Hotspots are major town junctions, and RTI rates differ over different stretches of the NH. In India, FIRs form a valuable source of RTI information. Information on different vehicle profile, RTI patterns, and their spatial and temporal trends can be used by administrators to devise effective strategies for RTI prevention by concentrating on the high-risk areas, thereby optimising the use of available personnel and resources. © 2014 John Wiley & Sons Ltd.

Space-based constraints on spatial and temporal patterns of NO(x) emissions in California, 2005-2008.

PubMed

Russell, Ashley R; Valin, Lukas C; Bucsela, Eric J; Wenig, Mark O; Cohen, Ronald C

2010-05-01

We describe ground and space-based measurements of spatial and temporal variation of NO(2) in four California metropolitan regions. The measurements of weekly cycles and trends over the years 2005-2008 observed both from the surface and from space are nearly identical to each other. Observed decreases in Los Angeles and the surrounding cities are 46% on weekends and 9%/year from 2005-2008. Similar decreases are observed in the San Francisco Bay area and in Sacramento. In the San Joaquin Valley cities of Fresno and Bakersfield weekend decreases are much smaller, only 27%, and the decreasing trend is only 4%/year. We describe evidence that the satellite observations provide a uniquely complete view of changes in spatial patterns over time. For example, we observe variations in the spatial pattern of weekday-weekend concentrations in the Los Angeles basin with much steeper weekend decreases at the eastern edge of the basin. We also observe that the spatial extent of high NO(2) in the San Joaquin Valley has not receded as much as it has for other regions in the state. Analysis of these measurements is used to describe observational constraints on temporal trends in emission sources in the different regions.

The effect of length and starting year on trend analyses of temperatures in Spanish mainland (1951-2010). Seasonal analyses: Spring (III)

NASA Astrophysics Data System (ADS)

Salinas Solé, Celia; Peña Angulo, Dhais; Gonzalez Hidalgo, Jose Carlos; Brunetti, Michele

2017-04-01

In this poster we applied the moving window approach (see Poster I of this collection) to analyze trends of spring and its corresponding months (March, April, May) temperature mean values of maximum (Tmax) and minimum (Tmin) in Spanish mainland to detect the effects of length period and starting year. Monthly series belong to Monthly Temperature dataset of Spanish mainland (MOTEDAS). Database contains in its grid format of 5236 pixels of monthly series (10x10 km). The threshold used in spatial analyses considers 20% of land under significant trend (p<0.05). The most striking results are as follow: • Seasonal Tmax shows that global trend was positive and significant until the mid 80's with higher values than 75% from between 1954-2010 to 1979-2010, being reduced after to the north region. So, from 1985-2010 no significant trend have been detected. Monthly analyses show differences. March trend is not significant (<20% of area) since 1974-2010, while significant trend in April and May varies between 1961-2010/1979-2010 and 1965-2010/1980-2010 respectively, clearly located in northern midland and Mediterranean coastland. • Spring Tmin trend analyses is significantly (>20%) during all temporal windows, notwithstanding NW do not show global significant trend, and in the most recent temporal windows only affect significantly SE. Monthly analyses also differ. Not significant trend is detected in March from 1979-2010, and from 1985-2010 in May, being April the month in any temporal windows with more than 20% of land affected by significant trend. • Spatial differences are detected between windows (South-North in March, East-West in April-May. We can conclude Tmax trend varies accordingly temporal windows dramatically in spring and no significance has been detected in the recent decades. Northern areas and Mediterranean coastland seems to be the most affected. Monthy Tmax trend spatial analyses confirm the heterogeneity of diurnal temperatures; different spatial gradients in windows have been detected between months. Seasonal Tmin show a more global temporal pattern. Spatial gradients of significance between months have been detected, in some sense contraries to the observed in Tmax.

Identification of trend in long term precipitation and reference evapotranspiration over Narmada river basin (India)

NASA Astrophysics Data System (ADS)

Pandey, Brij Kishor; Khare, Deepak

2018-02-01

Precipitation and reference evapotranspiration are key parameters in hydro-meteorological studies and used for agricultural planning, irrigation system design and management. Precipitation and evaporative demand are expected to be alter under climate change and affect the sustainable development. In this article, spatial variability and temporal trend of precipitation and reference evapotranspiration (ETo) were investigated over Narmada river basin (India), a humid tropical climatic region. In the present study, 12 and 28 observatory stations were selected for precipitation and ETo, respectively of 102-years period (1901-2002). A rigorous analysis for trend detection was carried out using non parametric tests such as Mann-Kendall (MK) and Spearman Rho (SR). Sen's slope estimator was used to analyze the rate of change in long term series. Moreover, all the stations of basin exhibit positive trend for annual ETo, while 8% stations indicate significant negative trend for mean annual precipitation, respectively. Change points of annual precipitation were identified around the year 1962 applying Buishand's and Pettit's test. Annual mean precipitation reduced by 9% in upper part while increased maximum by 5% in lower part of the basin due temporal changes. Although annual mean ETo increase by 4-12% in most of the region. Moreover, results of the study are very helpful in planning and development of agricultural water resources.

Semantic Annotation of Complex Text Structures in Problem Reports

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Throop, David R.; Fleming, Land D.

2011-01-01

Text analysis is important for effective information retrieval from databases where the critical information is embedded in text fields. Aerospace safety depends on effective retrieval of relevant and related problem reports for the purpose of trend analysis. The complex text syntax in problem descriptions has limited statistical text mining of problem reports. The presentation describes an intelligent tagging approach that applies syntactic and then semantic analysis to overcome this problem. The tags identify types of problems and equipment that are embedded in the text descriptions. The power of these tags is illustrated in a faceted searching and browsing interface for problem report trending that combines automatically generated tags with database code fields and temporal information.

Spatiotemporal Trends Analysis of Pyrethroid Sediment Concentrations Spanning 10 Years in a Residential Creek in California.

PubMed

Hall, Lenwood W; Anderson, Ronald D; Killen, William D

2016-02-01

The objective of this study was to assess temporal and spatial trends for eight pyrethroids monitored in sediment spanning 10 years from 2006 to 2015 in a residential stream in California (Pleasant Grove Creek). The timeframe for this study included sampling 3 years during a somewhat normal non-drought period (2006-2008) and 3 years during a severe drought period (2013-2015). Regression analysis of pyrethroid concentrations in Pleasant Grove Creek for 2006, 2007, 2008, 2012, 2013, 2014, and 2015 using ½ the detection limit for nondetected concentrations showed statistically significant declining trends for cyfluthrin, cypermethrin, deltamethrin, permethrin, and total pyrethoids. Additional trends analysis of the Pleasant Grove Creek pyrethroid data using only measured concentrations, without nondetected values, showed similar statistically significant declining trends for cyfluthrin, cypermethrin, deltamethrin, esfenvalerate, fenpropathrin, permethrin, and total pyrethroids. Spatial trends analysis for the specific creek sites showed that six of the eight pyrethroids had a greater number of sites with statistically significant declining concentrations. Possible reasons for reduced pyrethroid concentrations in the stream bed in Pleasant Grove Creek during this 10-year period are label changes in 2012 that reduced residential use and lack of precipitation during the later severe drought years of 2013-2015.

National Trends in Trace Metals Concentrations in Ambient Particulate Matter

NASA Astrophysics Data System (ADS)

McCarthy, M. C.; Hafner, H. R.; Charrier, J. G.

2007-12-01

Ambient measurements of trace metals identified as hazardous air pollutants (HAPs, air toxics) collected in the United States from 1990 to 2006 were analyzed for long-term trends. Trace metals analyzed include lead, manganese, arsenic, chromium, nickel, cadmium, and selenium. Visual and statistical analyses were used to identify and quantify temporal variations in air toxics at national and regional levels. Trend periods were required to be at least five years. Lead particles decreased in concentration at most monitoring sites, but trends in other metals were not consistent over time or spatially. In addition, routine ambient monitoring methods had method detection limits (MDLs) too high to adequately measure concentrations for trends analysis. Differences between measurement methods at urban and rural sites also confound trends analyses. Improvements in MDLs, and a better understanding of comparability between networks, are needed to better quantify trends in trace metal concentrations in the future.

Using FIESTA , an R-based tool for analysts, to look at temporal trends in forest estimates

Treesearch

Tracey S. Frescino; Paul L. Patterson; Elizabeth A. Freeman; Gretchen G. Moisen

2012-01-01

FIESTA (Forest Inventory Estimation for Analysis) is a user-friendly R package that supports the production of estimates for forest resources based on procedures from Bechtold and Patterson (2005). The package produces output consistent with current tools available for the Forest Inventory and Analysis National Program, such as FIDO (Forest Inventory Data Online) and...

[Temporal and spatial variations of extreme climatic events in Songnen Grassland, Northeast China during 1960-2014].

PubMed

Ma, Qi Yun; Zhang, Ji Quan; Lai, Quan; Zhang, Feng; Dong, Zhen Hua; A, Lu Si

2017-06-18

Fourteen extreme climatic indices related with main regional meteorological disasters and vegetation growth were calculated based on daily data from 13 meteorological stations during 1960-2014 in Songnen Grassland, Northeast China. Then, the variation trend and the spatial and temporal patterns of climatic extreme events were analyzed by using regression analysis, break trend analy-sis, Mann-Kendall test, Sen's slope estimator and moving t-test method. The results indicated that summer days (SU25), warm days (TX90P), warm nights (TN90P) and warm spell duration (WSDI) representing extremely high temperatures showed significant increasing trends (P<0.05). Meanwhile, frost days (FD0), cold days (TX10P), cold nights (TN10P) and cold spell duration indicator (CSDI) representing extremely low temperatures showed obviously decreasing trends. The magnitudes of changes in cold indices (FD0, TX10P, TN10P and CSDI) were clearly greater than those of warm indices (SU25, TX90P, TN90P and WSDI), and that changes in night indices were larger than those of day indices. Regional climate warming trend was obvious from 1970 to 2009, and the most occurrences of the abrupt changes in these indices were identified in this period. The extreme precipitation indices did not show obvious trend, in general, SDII and CDD experienced a slightly decreasing trend while RX5D, R95P, PRCPTOT and CWD witnessed a mildly increasing trend. It may be concluded that regional climate changed towards warming and slightly wetting in Songnen Grassland. The most sensitive region for extreme temperature was distributed in the south and north region. Additionally, the extreme temperature indices showed clearly spatial difference between the south and the north. As for the spatial variations of extreme precipitation indices, the climate could be characterized by becoming wetter in northern region, and getting drier in southern region, especially in southwestern region with a high drought risk.

Spatial and temporal trends of reference crop evapotranspiration and its influential variables in Yangtze River Delta, eastern China

NASA Astrophysics Data System (ADS)

Xu, Yu; Xu, Youpeng; Wang, Yuefeng; Wu, Lei; Li, Guang; Song, Song

2017-11-01

Reference crop evapotranspiration (ETo) is one of the most important links in hydrologic circulation and greatly affects regional agricultural production and water resource management. Its variation has drawn more and more attention in the context of global warming. We used the Penman-Monteith method of the Food and Agriculture Organization, based on meteorological factors such as air temperature, sunshine duration, wind speed, and relative humidity to calculate the ETo over 46 meteorological stations located in the Yangtze River Delta, eastern China, from 1957 to 2014. The spatial distributions and temporal trends in ETo were analyzed based on the modified Mann-Kendall trend test and linear regression method, while ArcGIS software was employed to produce the distribution maps. The multiple stepwise regression method was applied in the analysis of the meteorological variable time series to identify the causes of any observed trends in ETo. The results indicated that annual ETo showed an obvious spatial pattern of higher values in the north than in the south. Annual increasing trends were found at 34 meteorological stations (73.91 % of the total), which were mainly located in the southeast. Among them, 12 (26.09 % of the total) stations showed significant trends. We saw a dominance of increasing trends in the monthly ETo except for January, February, and August. The high value zone of monthly ETo appeared in the northwest from February to June, mid-south area from July to August, and southeast coastal area from September to January. The research period was divided into two stages—stage I (1957-1989) and stage II (1990-2014)—to investigate the long-term temporal ETo variation. In stage I, almost 85 % of the total stations experienced decreasing trends, while more than half of the meteorological stations showed significant increasing trends in annual ETo during stage II except in February and September. Relative humidity, wind speed, and sunshine duration were identified as the most dominant meteorological variables influencing annual ETo changes. The results are expected to assist water resource managers and policy makers in making better planning decisions in the research region.

Assessing the influence of small fires on trends in fire regime features at mainland Spain

NASA Astrophysics Data System (ADS)

Jiménez-Ruano, Adrián; Rodrigues Mimbrero, Marcos; de la Riva Fernández, Juan

2017-04-01

Small fires, i.e. fires smaller than 1 Ha, represent a huge proportion of total wildfire occurrence in the Mediterranean region. In the case of Spain, around 53% of fires in the period 1988-2013 fall into this category according to the Spanish EGIF statistics. However, the proportion of small fires is not stationary over time. Small fires are usually excluded from most analysis, given the chance of introducing or falling into temporal bias, being almost mandatory in those assessments using data before the 90s. Inconsistences and inhomogeneity problems related to the diversity of criteria and/or registration procedures among Autonomous Regions are found before that date, although it is widely agreed that small fires are consistently registered starting from 1988. Nevertheless, in terms of fire regimen characterization it is important to know to what extent small fires contribute to the overall fire behaviour. The aim of this study is to analyse spatial-temporal trends of several fire features such as total number of fires and burned area, number and burned area of natural and human fires, and the proportion of natural/human cause in the period 1988-2013 at province level (NUTS3). The analysis is conducted at the mainland Spain at annual and seasonal time scales. We are mainly interested in exploring differences in spatial-temporal trends including or excluding small fires and dealing with them separately as well. This allows determining the extent to which small fires may affect fire regime characterization. We employed a Mann-Kendall test for trend detection and Sen's slope to evaluate the magnitude of the change. Both tests were applied for each fire feature aggregated at NUTS3 level for both autumn-winter and spring-summer seasons. Our results show significant changes in the evolution of annual wildfire frequency; especially strong when small fires are accounted for. A similar outcome was observed in natural and human number fires during the spring-summer season. The increase in number of fires seems to be reversed during autumn-winter. At seasonal scale, the inclusion of small fires allows to detect significant trends in all of fire frequency features, except natural fires. In turn, neither burned area features do not significantly affect the trends through incorporating small fires. Therefore, the inclusion/exclusion of small fires do influence observed trends mostly in terms of fire frequency.

Surveillance of antimicrobial resistance in clinical isolates of Pasteurella multocida and Streptococcus suis from Ontario swine.

PubMed

Glass-Kaastra, Shiona K; Pearl, David L; Reid-Smith, Richard J; McEwen, Beverly; Slavic, Durda; Fairles, Jim; McEwen, Scott A

2014-10-01

Susceptibility results for Pasteurella multocida and Streptococcus suis isolated from swine clinical samples were obtained from January 1998 to October 2010 from the Animal Health Laboratory at the University of Guelph, Guelph, Ontario, and used to describe variation in antimicrobial resistance (AMR) to 4 drugs of importance in the Ontario swine industry: ampicillin, tetracycline, tiamulin, and trimethoprim-sulfamethoxazole. Four temporal data-analysis options were used: visualization of trends in 12-month rolling averages, logistic-regression modeling, temporal-scan statistics, and a scan with the "What's strange about recent events?" (WSARE) algorithm. The AMR trends varied among the antimicrobial drugs for a single pathogen and between pathogens for a single antimicrobial, suggesting that pathogen-specific AMR surveillance may be preferable to indicator data. The 4 methods provided complementary and, at times, redundant results. The most appropriate combination of analysis methods for surveillance using these data included temporal-scan statistics with a visualization method (rolling-average or predicted-probability plots following logistic-regression models). The WSARE algorithm provided interesting results for quality control and has the potential to detect new resistance patterns; however, missing data created problems for displaying the results in a way that would be meaningful to all surveillance stakeholders.

Surveillance of antimicrobial resistance in clinical isolates of Pasteurella multocida and Streptococcus suis from Ontario swine

PubMed Central

Glass-Kaastra, Shiona K.; Pearl, David L.; Reid-Smith, Richard J.; McEwen, Beverly; Slavic, Durda; Fairles, Jim; McEwen, Scott A.

2014-01-01

Susceptibility results for Pasteurella multocida and Streptococcus suis isolated from swine clinical samples were obtained from January 1998 to October 2010 from the Animal Health Laboratory at the University of Guelph, Guelph, Ontario, and used to describe variation in antimicrobial resistance (AMR) to 4 drugs of importance in the Ontario swine industry: ampicillin, tetracycline, tiamulin, and trimethoprim–sulfamethoxazole. Four temporal data-analysis options were used: visualization of trends in 12-month rolling averages, logistic-regression modeling, temporal-scan statistics, and a scan with the “What’s strange about recent events?” (WSARE) algorithm. The AMR trends varied among the antimicrobial drugs for a single pathogen and between pathogens for a single antimicrobial, suggesting that pathogen-specific AMR surveillance may be preferable to indicator data. The 4 methods provided complementary and, at times, redundant results. The most appropriate combination of analysis methods for surveillance using these data included temporal-scan statistics with a visualization method (rolling-average or predicted-probability plots following logistic-regression models). The WSARE algorithm provided interesting results for quality control and has the potential to detect new resistance patterns; however, missing data created problems for displaying the results in a way that would be meaningful to all surveillance stakeholders. PMID:25355992

Spatio-Temporal Epidemiology of Viral Hepatitis in China (2003-2015): Implications for Prevention and Control Policies.

PubMed

Zhu, Bin; Liu, Jinlin; Fu, Yang; Zhang, Bo; Mao, Ying

2018-04-02

Viral hepatitis, as one of the most serious notifiable infectious diseases in China, takes heavy tolls from the infected and causes a severe economic burden to society, yet few studies have systematically explored the spatio-temporal epidemiology of viral hepatitis in China. This study aims to explore, visualize and compare the epidemiologic trends and spatial changing patterns of different types of viral hepatitis (A, B, C, E and unspecified, based on the classification of CDC) at the provincial level in China. The growth rates of incidence are used and converted to box plots to visualize the epidemiologic trends, with the linear trend being tested by chi-square linear by linear association test. Two complementary spatial cluster methods are used to explore the overall agglomeration level and identify spatial clusters: spatial autocorrelation analysis (measured by global and local Moran's I) and space-time scan analysis. Based on the spatial autocorrelation analysis, the hotspots of hepatitis A remain relatively stable and gradually shrunk, with Yunnan and Sichuan successively moving out the high-high (HH) cluster area. The HH clustering feature of hepatitis B in China gradually disappeared with time. However, the HH cluster area of hepatitis C has gradually moved towards the west, while for hepatitis E, the provincial units around the Yangtze River Delta region have been revealing HH cluster features since 2005. The space-time scan analysis also indicates the distinct spatial changing patterns of different types of viral hepatitis in China. It is easy to conclude that there is no one-size-fits-all plan for the prevention and control of viral hepatitis in all the provincial units. An effective response requires a package of coordinated actions, which should vary across localities regarding the spatial-temporal epidemic dynamics of each type of virus and the specific conditions of each provincial unit.

Spatial and temporal trends in contaminant concentrations in Hexagenia nymphs following a coal ash spill at the Tennessee Valley Authority's Kingston Fossil Plant

DOE PAGES

Baker, Tyler F; Jett, Robert Trent; Smith, John G.; ...

2016-02-25

A dike failure at the Tennessee Valley Authority Kingston Fossil Plant in East Tennessee, United States, in December 2008, released approximately 4.1 million m3 of coal ash into the Emory River. From 2009 through 2012, samples of mayfly nymphs ( Hexagenia bilineata) were collected each spring from sites in the Emory, Clinch, and Tennessee Rivers upstream and downstream of the spill. Samples were analyzed for 17 metals. Concentrations of metals were generally highest the first 2 miles downstream of the spill, and then decreased with increasing distance from the spill. Arsenic, B, Ba, Be, Mo, Sb, Se, Sr, and Vmore » appeared to have strong ash signatures, whereas Co, Cr, Cu, Ni, and Pb appeared to be associated with ash and other sources. Furthermore, the concentrations for most of these contaminants were modest and are unlikely to cause widespread negative ecological effects. Trends in Hg, Cd, and Zn suggested little (Hg) or no (Cd, Zn) association with ash. Temporal trends suggested that concentrations of ash-related contaminants began to subside after 2010, but because of the limited time period of that analysis (4 yr), further monitoring is needed to verify this trend. The present study provides important information on the magnitude of contaminant exposure to aquatic receptors from a major coal ash spill, as well as spatial and temporal trends for transport of the associated contaminants in a large open watershed. Environ Toxicol Chem 2016;35:1159 1171. Published 2015 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.« less

Multi-regional synthesis of temporal trends in biotic assemblages in streams and rivers of the continental United States

USGS Publications Warehouse

Miller, Matthew P.; Brasher, Anne M.D.; Keenen, Jonathan G.

2013-01-01

Biotic assemblages in aquatic ecosystems are excellent integrators and indicators of changing environmental conditions within a watershed. Therefore, temporal changes in abiotic environmental variables often can be inferred from temporal changes in biotic assemblages. Algae, macroinvertebrate, and fish assemblage data were collected from 91 sampling sites in 4 geographic regions (northeastern/north-central, southeastern, south-central, and western), collectively encompassing the continental United States, from 1993 to 2009 as part of the U.S. Geological Survey National Water-Quality Assessment Program. This report uses a multivariate approach to synthesize temporal trends in biotic assemblages and correlations with relevant abiotic parameters as a function of biotic assemblage, geographic region, and land use. Of the three groups of biota, algal assemblages had temporal trends at the greatest percentage of sites. Of the regions, a greater percentage of sites in the northeastern/north-central and western regions had temporal trends in biotic assemblages. In terms of land use, a greater percentage of watersheds draining agricultural, urban, and undeveloped areas had significant temporal changes in biota, as compared to watersheds with mixed use. Correlations between biotic assemblages and abiotic variables indicate that, in general, macroinvertebrate assemblages correlated with water quality and fish assemblages correlated with physical habitat. Taken together, results indicate that there are regional differences in how individual biotic assemblages (algae, macroinvertebrates, and fish) respond to different abiotic drivers of change.

Research on Visual Analysis Methods of Terrorism Events

NASA Astrophysics Data System (ADS)

Guo, Wenyue; Liu, Haiyan; Yu, Anzhu; Li, Jing

2016-06-01

Under the situation that terrorism events occur more and more frequency throughout the world, improving the response capability of social security incidents has become an important aspect to test governments govern ability. Visual analysis has become an important method of event analysing for its advantage of intuitive and effective. To analyse events' spatio-temporal distribution characteristics, correlations among event items and the development trend, terrorism event's spatio-temporal characteristics are discussed. Suitable event data table structure based on "5W" theory is designed. Then, six types of visual analysis are purposed, and how to use thematic map and statistical charts to realize visual analysis on terrorism events is studied. Finally, experiments have been carried out by using the data provided by Global Terrorism Database, and the results of experiments proves the availability of the methods.

Using a virtual reality temporal bone simulator to assess otolaryngology trainees.

PubMed

Zirkle, Molly; Roberson, David W; Leuwer, Rudolf; Dubrowski, Adam

2007-02-01

The objective of this study is to determine the feasibility of computerized evaluation of resident performance using hand motion analysis on a virtual reality temporal bone (VR TB) simulator. We hypothesized that both computerized analysis and expert ratings would discriminate the performance of novices from experienced trainees. We also hypothesized that performance on the virtual reality temporal bone simulator (VR TB) would differentiate based on previous drilling experience. The authors conducted a randomized, blind assessment study. Nineteen volunteers from the Otolaryngology-Head and Neck Surgery training program at the University of Toronto drilled both a cadaveric TB and a simulated VR TB. Expert reviewers were asked to assess operative readiness of the trainee based on a blind video review of their performance. Computerized hand motion analysis of each participant's performance was conducted. Expert raters were able to discriminate novices from experienced trainees (P < .05) on cadaveric temporal bones, and there was a trend toward discrimination on VR TB performance. Hand motion analysis showed that experienced trainees had better movement economy than novices (P < .05) on the VR TB. Performance, as measured by hand motion analysis on the VR TB simulator, reflects trainees' previous drilling experience. This study suggests that otolaryngology trainees could accomplish initial temporal bone training on a VR TB simulator, which can provide feedback to the trainee, and may reduce the need for constant faculty supervision and evaluation.

Seasonal and annual precipitation time series trend analysis in North Carolina, United States

NASA Astrophysics Data System (ADS)

Sayemuzzaman, Mohammad; Jha, Manoj K.

2014-02-01

The present study performs the spatial and temporal trend analysis of the annual and seasonal time-series of a set of uniformly distributed 249 stations precipitation data across the state of North Carolina, United States over the period of 1950-2009. The Mann-Kendall (MK) test, the Theil-Sen approach (TSA) and the Sequential Mann-Kendall (SQMK) test were applied to quantify the significance of trend, magnitude of trend, and the trend shift, respectively. Regional (mountain, piedmont and coastal) precipitation trends were also analyzed using the above-mentioned tests. Prior to the application of statistical tests, the pre-whitening technique was used to eliminate the effect of autocorrelation of precipitation data series. The application of the above-mentioned procedures has shown very notable statewide increasing trend for winter and decreasing trend for fall precipitation. Statewide mixed (increasing/decreasing) trend has been detected in annual, spring, and summer precipitation time series. Significant trends (confidence level ≥ 95%) were detected only in 8, 7, 4 and 10 nos. of stations (out of 249 stations) in winter, spring, summer, and fall, respectively. Magnitude of the highest increasing (decreasing) precipitation trend was found about 4 mm/season (- 4.50 mm/season) in fall (summer) season. Annual precipitation trend magnitude varied between - 5.50 mm/year and 9 mm/year. Regional trend analysis found increasing precipitation in mountain and coastal regions in general except during the winter. Piedmont region was found to have increasing trends in summer and fall, but decreasing trend in winter, spring and on an annual basis. The SQMK test on "trend shift analysis" identified a significant shift during 1960 - 70 in most parts of the state. Finally, the comparison between winter (summer) precipitations with the North Atlantic Oscillation (Southern Oscillation) indices concluded that the variability and trend of precipitation can be explained by the Oscillation indices for North Carolina.

Topic Time Series Analysis of Microblogs

DTIC Science & Technology

2014-10-01

network, may be closer to a media distribution site, where the media is user produced [14]. Analysis of the text content includes both general models as...is generated by Instagram . Topic 80, Distance: 143.2101 Top words: 1. rawr 2. ˆ0ˆ 3. kill 4. jurassic 5. dinosaur Analysis: This topic is quite...data, lack of reliable event information, hidden temporal trends, and the vastly diverse nature of content . In the present work, we examine spatio

Serum Testosterone Kinetics After Brachytherapy for Clinically Localized Prostate Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taira, Al V.; Merrick, Gregory S., E-mail: gmerrick@urologicresearchinstitute.org; Galbreath, Robert W.

Purpose: To evaluate temporal changes in testosterone after prostate brachytherapy and investigate the potential impact of these changes on response to treatment. Methods and Materials: Between January 2008 and March 2009, 221 consecutive patients underwent Pd-103 brachytherapy without androgen deprivation for clinically localized prostate cancer. Prebrachytherapy prostate-specific antigen (PSA) and serum testosterone were obtained for each patient. Repeat levels were obtained 3 months after brachytherapy and at least every 6 months thereafter. Multiple clinical, treatment, and dosimetric parameters were evaluated to determine an association with temporal testosterone changes. In addition, analysis was conducted to determine if there was an associationmore » between testosterone changes and treatment outcomes or the occurrence of a PSA spike. Results: There was no significant difference in serum testosterone over time after implant (p = 0.57). 29% of men experienced an increase {>=}25%, 23% of men experienced a decrease {>=}25%, and the remaining 48% of men had no notable change in testosterone over time. There was no difference in testosterone trends between men who received external beam radiotherapy and those who did not (p = 0.12). On multivariate analysis, preimplant testosterone was the only variable that consistently predicted for changes in testosterone over time. Men with higher than average testosterone tended to experience drop in testosterone (p < 0.001), whereas men with average or below average baseline testosterone had no significant change. There was no association between men who experienced PSA spike and testosterone temporal trends (p = 0.50) nor between initial PSA response and testosterone trends (p = 0.21). Conclusion: Prostate brachytherapy does not appear to impact serum testosterone over time. Changes in serum testosterone do not appear to be associated with PSA spike phenomena nor with initial PSA response to treatment; therefore, PSA response does not seem related to temporal testosterone changes.« less

Response of surface water chemistry to reduced levels of acid precipitation: Comparison of trends in two regions of New York, USA

USGS Publications Warehouse

Burns, Douglas A.; McHale, M.R.; Driscoll, C.T.; Roy, K.M.

2006-01-01

In light of recent reductions in sulphur (S) and nitrogen (N) emissions mandated by Title IV of the Clean Air Act Amendments of 1990, temporal trends and trend coherence in precipitation (1984-2001 and 1992-2001) and surface water chemistry (1992-2001) were determined in two of the most acid-sensitive regions of North America, i.e. the Catskill and Adirondack Mountains of New York. Precipitation chemistry data from six sites located near these regions showed decreasing sulphate (SO42-), nitrate (NO3-), and base cation (CB) concentrations and increasing pH during 1984-2001, but few significant trends during 1992-2001. Data from five Catskill streams and 12 Adirondack lakes showed decreasing trends in SO42- concentrations at all sites, and decreasing trends in NO3-, CB, and H+ concentrations and increasing trends in dissolved organic carbon at most sites. In contrast, acid-neutralizing capacity (ANC increased significantly at only about half the Adirondack lakes and in one of the Catskill streams. Flow correction prior to trend analysis did not change any trend directions and had little effect on SO42- trends, but it caused several significant non-flow-corrected trends in NO3- and ANC to become non-significant, suggesting that trend results for flow-sensitive constituents are affected by flow-related climate variation. SO42- concentrations showed high temporal coherence in precipitation, surface waters, and in precipitation-surface water comparisons, reflecting a strong link between S emissions, precipitation SO42- concentrations, and the processes that affect S cycling within these regions. NO3- and H+ concentrations and ANC generally showed weak coherence, especially in surface waters and in precipitation-surface water comparisons, indicating that variation in local-scale processes driven by factors such as climate are affecting trends in acid-base chemistry in these two regions. Copyright ?? 2005 John Wiley & Sons, Ltd.

Trend analysis of aerosol optical thickness and Ångström exponent derived from the global AERONET spectral observations

NASA Astrophysics Data System (ADS)

Yoon, J.; von Hoyningen-Huene, W.; Kokhanovsky, A. A.; Vountas, M.; Burrows, J. P.

2012-06-01

Regular aerosol observations based on well-calibrated instruments have led to a better understanding of the aerosol radiative budget on Earth. In recent years, these instruments have played an important role in the determination of the increase of anthropogenic aerosols by means of long-term studies. Only few investigations regarding long-term trends of aerosol optical characteristics (e.g. aerosol optical thickness (AOT) and Ångström exponent (ÅE)) have been derived from ground-based observations. This paper aims to derive and discuss linear trends of AOT (440, 675, 870, and 1020 nm) and ÅE (440-870 nm) using AErosol RObotic NETwork (AERONET) level 2.0 spectral observations. Additionally, temporal trends of coarse- and fine-mode dominant AOTs (CdAOT and FdAOT) have been estimated by applying an aerosol classification based on accurate ÅE and Ångström exponent difference (ÅED). In order to take into account the fact that cloud disturbance is having a significant influence on the trend analysis of aerosols, we introduce a weighted least squares regression depending on two weights: (1) monthly standard deviation (σt) and (2) number of observations per month (nt). Temporal increase of FdAOTs (440 nm) prevails over newly industrializing countries in East Asia (weighted trends; +6.23% yr-1 at Beijing) and active agricultural burning regions in South Africa (+1.89% yr-1 at Mongu). On the other hand, insignificant or negative trends for FdAOTs are detected over Western Europe (+0.25% yr-1 at Avignon and -2.29% yr-1 at Ispra) and North America (-0.52% yr-1 for GSFC and -0.01% yr-1 at MD_Science_Center). Over desert regions, both increase and decrease of CdAOTs (+3.37% yr-1 at Solar_Village and -1.18% yr-1 at Ouagadougou) are observed depending on meteorological conditions.

Temporal trends and spatial distribution of unsafe abortion in Brazil, 1996-2012

PubMed Central

Martins-Melo, Francisco Rogerlândio; Lima, Mauricélia da Silveira; Alencar, Carlos Henrique; Ramos, Alberto Novaes; Carvalho, Francisco Herlânio Costa; Machado, Márcia Maria Tavares; Heukelbach, Jorg

2014-01-01

OBJECTIVE To analyze temporal trends and distribution patterns of unsafe abortion in Brazil. METHODS Ecological study based on records of hospital admissions of women due to abortion in Brazil between 1996 and 2012, obtained from the Hospital Information System of the Ministry of Health. We estimated the number of unsafe abortions stratified by place of residence, using indirect estimate techniques. The following indicators were calculated: ratio of unsafe abortions/100 live births and rate of unsafe abortion/1,000 women of childbearing age. We analyzed temporal trends through polynomial regression and spatial distribution using municipalities as the unit of analysis. RESULTS In the study period, a total of 4,007,327 hospital admissions due to abortions were recorded in Brazil. We estimated a total of 16,905,911 unsafe abortions in the country, with an annual mean of 994,465 abortions (mean unsafe abortion rate: 17.0 abortions/1,000 women of childbearing age; ratio of unsafe abortions: 33.2/100 live births). Unsafe abortion presented a declining trend at national level (R2: 94.0%, p < 0.001), with unequal patterns between regions. There was a significant reduction of unsafe abortion in the Northeast (R2: 93.0%, p < 0.001), Southeast (R2: 92.0%, p < 0.001) and Central-West regions (R2: 64.0%, p < 0.001), whereas the North (R2: 39.0%, p = 0.030) presented an increase, and the South (R2: 22.0%, p = 0.340) remained stable. Spatial analysis identified the presence of clusters of municipalities with high values for unsafe abortion, located mainly in states of the North, Northeast and Southeast Regions. CONCLUSIONS Unsafe abortion remains a public health problem in Brazil, with marked regional differences, mainly concentrated in the socioeconomically disadvantaged regions of the country. Qualification of attention to women’s health, especially to reproductive aspects and attention to pre- and post-abortion processes, are necessary and urgent strategies to be implemented in the country. PMID:25119946

Temporal and spatial characteristics of the water pollutant concentration in Huaihe River Basin from 2003 to 2012, China.

PubMed

Dou, Ming; Zhang, Yan; Li, Guiqiu

2016-09-01

Based on the monitoring data of 78 monitoring stations from 2003 to 2012, five key water quality indexes (biochemical oxygen demand: BOD5, permanganate index: CODMn, dissolved oxygen: DO, ammonium nitrogen: NH3-N, and total phosphorus: TP) were selected to analyze their temporal and spatial characteristics in the highly disturbed Huaihe River Basin via Mann-Kendall trend analysis and boxplot analysis. The temporal and spatial variations of water pollutant concentrations in the Huaihe River Basin were investigated and analyzed to provide a scientific basis for water pollution control, water environment protection, and ecological restoration. The results indicated that the Yinghe River, Quanhe River, Honghe River, Guohe River, and Baohe River were the most seriously polluted rivers, followed by Hongze Lake, Luoma Lake, Yishuhe River, and Nansi Lake. BOD5, CODMn, and NH3-N were the major pollution indexes, for which the monitoring stations reported that more than 40 % of the water quality concentrations exceeded the class IV level. There were 21, 50, 36, and 21 monitoring stations that recorded significantly decreasing trends for BOD5, CODMn, NH3-N, and TP, respectively, and 39 monitoring stations showed a significantly increasing trend for DO. Moreover, the water quality concentrations had a certain concentricity and volatility according to boxplot analysis for the 20 monitoring stations. The majority of monitoring stations recorded a large fluctuation for the monitoring indexes in 2003 and 2004, which indicated that the water quality concentrations were unstable. According to the seasonal variations of the water quality concentrations in the mainstream of Huaihe River, the monthly variation trends of the BOD5, CODMn, DO, NH3-N, and TP concentrations were basically consistent among the seven monitoring stations. The BOD5, CODMn, NH3-N, and TP concentrations were affected by the change of the stream discharge; changes in DO and NH3-N concentrations were influenced by the regional environmental temperature, and the DO and NH3-N concentrations decreased when the water temperature increased.

Assessing spatio-temporal trend of vector breeding and dengue fever incidence in association with meteorological conditions.

PubMed

Malik, Afifa; Yasar, Abdullah; Tabinda, Amtul Bari; Zaheer, Ihsan Elahi; Malik, Khalida; Batool, Adeeba; Mahfooz, Yusra

2017-04-01

Th aim of this study is to investigate spatio-temporal trends of dengue vector breeding and epidemic (disease incidence) influenced by climatic factors. The spatio-temporal (low-, medium-, and high-intensity periods) evaluation of entomological and epidemiological investigations along with climatic factors like rainfall (RF), temperature (T max ), relative humidity (RH), and larval indexing was conducted to develop correlations in the area of Lahore, Pakistan. The vector abundance and disease transmission trend was geo-tagged for spatial insight. The sufficient rainfall events and optimum temperature and relative humidity supported dengue vector breeding with high larval indices for water-related containers (27-37%). Among temporal analysis, the high-intensity period exponentially projected disease incidence followed by post-rainfall impacts. The high larval incidence that was observed in early high-intensity periods effected the dengue incidence. The disease incidence had a strong association with RF (r = 0.940, α = 0.01). The vector larva occurrence (r = 0.017, α = 0.05) influenced the disease incidence. Similarly, RH (r = 0.674, α = 0.05) and average T max (r = 0.307, α = 0.05) also induced impact on the disease incidence. In this study, the vulnerability to dengue fever highly correlates with meteorological factors during high-intensity period. It provides area-specific understanding of vector behavior, key containers, and seasonal patterns of dengue vector breeding and disease transmission which is essential for preparing an effective prevention plan against the vector.

Investigating aerosol properties in Peninsular Malaysia via the synergy of satellite remote sensing and ground-based measurements

NASA Astrophysics Data System (ADS)

Kanniah, Kasturi Devi; Lim, Hui Qi; Kaskaoutis, Dimitris G.; Cracknell, Arthur P.

2014-03-01

Spatio-temporal variation and trends in atmospheric aerosols as well as their impact on solar radiation and clouds are crucial for regional and global climate change assessment. These topics are not so well-documented over Malaysia, the fact that it receives considerable amounts of pollutants from both local and trans-boundary sources. The present study aims to analyse the spatio-temporal evolution and decadal trend of Aerosol Optical Depth (AOD) from Terra and Aqua MODIS sensors, to identify different types and origin of aerosols and explore the link between aerosols and solar radiation. AOD and fine-mode fraction (FMF) products from MODIS, AOD and Ångström Exponent (AE) values from AERONET stations along with ground-based PM10 measurements and solar radiation recordings at selected sites in Peninsular Malaysia are used for this scope. The MODIS AODs exhibit a wide spatio-temporal variation over Peninsular Malaysia, while Aqua AOD is consistently lower than that from Terra. The AOD shows a neutral-to-declining trend during the 2000s (Terra satellite), while that from Aqua exhibits an increasing trend (~ 0.01 per year). AERONET AODs exhibit either insignificant diurnal variation or higher values during the afternoon, while their short-term availability does not allow for a trend analysis. Moreover, the PM10 concentrations exhibit a general increasing trend over the examined locations. The sources and destination of aerosols are identified via the HYSPLIT trajectory model, revealing that aerosols during the dry season (June to September) are mainly originated from the west and southwest (Sumatra, Indonesia), while in the wet season (November to March) they are mostly associated with the northeast monsoon winds from the southern China Sea. Different aerosol types are identified via the relationship of AOD with FMF, revealing that the urban and biomass-burning aerosols are the most abundant over the region contributing to a significant reduction (~- 0.21 MJ m- 2) of the solar radiation.

Urine sodium excretion increased slightly among U.S. adults between 1988 and 2010.

PubMed

Pfeiffer, Christine M; Hughes, Jeffery P; Cogswell, Mary E; Burt, Vicki L; Lacher, David A; Lavoie, Donna J; Rabinowitz, Daniel J; Johnson, Clifford L; Pirkle, James L

2014-05-01

Little information is available on temporal trends in sodium intake in the U.S. population using urine sodium excretion as a biomarker. Our aim was to assess 1988-2010 trends in estimated 24-h urine sodium (24hUNa) excretion among U.S. adults (age 20-59 y) participating in the cross-sectional NHANES. We used subsamples from a 1988-1994 convenience sample, a 2003-2006 one-third random sample, and a 2010 one-third random sample to comply with resource constraints. We estimated 24hUNa excretion from measured sodium concentrations in spot urine samples by use of calibration equations (for men and women) derived from the International Cooperative Study on Salt, Other Factors, and Blood Pressure study. Estimated 24hUNa excretion increased over the 20-y period [1988-1994, 2003-2006, and 2010; means ± SEMs (n): 3160 ± 38.4 mg/d (1249), 3290 ± 29.4 mg/d (1235), and 3290 ± 44.4 mg/d (525), respectively; P-trend = 0.022]. We observed significantly higher mean estimated 24hUNa excretion in each survey period (P < 0.001) for men compared with women (31-33%) and for persons with a higher body mass index (BMI; 32-35% for obese vs. normal weight) or blood pressure (17-26% for hypertensive vs. normal blood pressure). After adjusting for age, sex, and race-ethnicity, temporal trends in mean estimated 24hUNa excretion remained significant (P-trend = 0.004). We observed no temporal trends in mean estimated 24hUNa excretion among BMI subgroups, nor after adjusting for BMI. Although several limitations apply to this analysis (the use of a convenience sample in 1988-1994 and using estimated 24hUNa excretion as a biomarker of sodium intake), these first NHANES data suggest that mean estimated 24hUNa excretion increased slightly in U.S. adults over the past 2 decades, and this increase may be explained by a shift in the distribution of BMI.

Spatio-temporal seasonal drought patterns in Europe from 1950 to 2015

NASA Astrophysics Data System (ADS)

Spinoni, Jonathan; Naumann, Gustavo; Vogt, Jürgen

2016-04-01

Drought is one of the natural disasters with severe impacts in Europe, not only in areas which frequently experience water scarcity such as the Mediterranean, but also in temperate or continental climates such as Central and Eastern Europe and even in cold regions such as Scandinavia and Iceland. In this study the spatio-temporal patterns of seasonal meteorological droughts in Europe between 1950 and 2015 are investigated using the Standardized Precipitation Index (SPI) and the Standardized Precipitation-Evapotranspiration Index (SPEI). Since the focus is on the analysis of seasonal drought trends, indicators were calculated for 3 monthly accumulation periods. The input variables of precipitation and temperature were derived from E-OBS grids (v11-v12) at a spatial resolution of 0.25°x0.25°. Seasonal trends of drought frequency and severity were analyzed for moderate (SPI or SPEI <-1.0) and extreme (SPI or SPEI <-2.0) events during the periods 1950-2015 and 1981-2015. For the moderate events, results of the SPI analysis (precipitation driven) demonstrate a significant tendency towards less frequent and severe droughts in Northern Europe and Russia, especially in winter and spring; oppositely, an increasing trend is visible in Southern Europe, mainly in spring and summer. According to the SPEI analysis (precipitation and temperature driven) Northern Europe shows wetting patterns, while Southern and Eastern Europe show a more remarkable drying tendency, especially in summer and autumn for drought frequency and in every season for drought severity. The evolution towards drier conditions is more relevant from 1981 onwards, both in terms of frequency and severity. This is especially true for Central Europe in spring, for the Mediterranean in summer, and for Eastern Europe in autumn. Extreme events follow similar patterns, but in autumn no spatially coherent trend can be found.

The spatiotemporal changes in precipitation extremes over Canada and their connections to large-scale climate patterns

NASA Astrophysics Data System (ADS)

Yang, Y.; Gan, T. Y.; Tan, X.

2017-12-01

In the past few decades, there have been more extreme climate events around the world, and Canada has also suffered from numerous extreme precipitation events. In this paper, trend analysis, change point analysis, probability distribution function, principal component analysis and wavelet analysis were used to investigate the spatial and temporal patterns of extreme precipitation in Canada. Ten extreme precipitation indices were calculated using long-term daily precipitation data from 164 gauging stations. Several large-scale climate patterns such as El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Pacific-North American (PNA), and North Atlantic Oscillation (NAO) were selected to analyze the relationships between extreme precipitation and climate indices. Convective Available Potential Energy (CAPE), specific humidity, and surface temperature were employed to investigate the potential causes of the trends.The results show statistically significant positive trends for most indices, which indicate increasing extreme precipitation. The majority of indices display more increasing trends along the southern border of Canada while decreasing trends dominate in the central Canadian Prairies (CP). In addition, strong connections are found between the extreme precipitation and climate indices and the effects of climate pattern differ for each region. The seasonal CAPE, specific humidity, and temperature are found to be closely related to Canadian extreme precipitation.

Temporal trend of the snow-related variables in Sierra Nevada in the last years: An analysis combining Earth Observation and hydrological modelling

NASA Astrophysics Data System (ADS)

Pérez-Luque, Antonio J.; Herrero, Javier; Bonet, Francisco J.; Pérez-Pérez, Ramón

2016-04-01

Climate change is causing declines in snow-cover extent and duration in European mountain ranges. This is especially important in Mediterranean mountain ranges where the observed trends towards precipitation and higher temperatures can provoke problems of water scarcity. In this work, we analyzed temporal trends (2000 to 2014) of snow-related variables obtained from satellite and modelling data in Sierra Nevada, a Mediterranean high-mountain range located in Southern Spain, at 37°N. Snow cover indicators (snow-cover duration, snow-cover onset dates and snow-cover melting dates) were obtained by processing images of MOD10A2 MODIS product using an automated workflow. Precipitation data were obtained using WiMMed, a complete and fully distributed hydrological model that is used to map the annual rainfall and snowfall with a resolution of 30x30 m over the whole study area. It uses expert algorithms to interpolate precipitation and temperature at an hourly scale, and simulates partition of precipitation into snowfall with several methods. For each snow-related indicator (snow-covers and snowfall), a trend analysis was applied at the MODIS pixel scale during the study period (2000-2014). We applied Mann-Kendall test and Theil-Sen slope estimation in each of the pixels comprising Sierra Nevada. The trend analysis assesses the intensity, magnitude and degree of statistical significance during the period analysed. The spatial pattern of these trends was explored according to elevation ranges. Finally, we explored the relationship between trends of snow-cover related indicators and precipitation trends. Our results show that snow-cover has undergone significant changes in the last 14 years. 80 % of the pixels covering Sierra Nevada showed a negative trend in the duration of snow-cover. We also observed a delay in the snow-cover onset date (68.03 % pixels showing a positive trend in the snow-cover onset date) and an advance in the melt date (80.72 % of pixels followed a negative trend for the snow-cover melting date). Precipitation does not show a significant trend for these years, even though its inter-annual variability has been outstanding. The maximum mean annual precipitation of 906 mm/year doubles the mean precipitation, which somehow compensates for the occurrence of a sequence of dry years with a minimum of 250 mm/year. The assessment of the spatial pattern of snow cover duration shows that both the trend and the slope of the trend becomes more pronounced with elevation. At higher elevations the snow-cover duration decreased an average of 3 days from 2000-2014. This research has been funded by ECOPOTENTIAL (Improving future ecosystem benefits through Earth Observations) Horizon 2020 EU project, and Sierra Nevada Global Change Observatory (LTER-site)

Temporal Trend in Wood Dust Exposure During the Production of Wood Pellets.

PubMed

Eriksson, Kåre; Bryngelsson, Ing-Liss; Hagström, Katja

2017-05-01

Wood dust data collected in the production of wood pellets during 2001 to 2013 were evaluated to study a temporal trend in inhalation exposure. A linear mixed effects model of natural ln-transformed data was used to express the relative annual difference in inhalation wood dust exposure. There was an annual decrease of -20.5% of the geometric mean wood dust exposure during 2001 until 2013. The results were based on 617 inhalable dust samples collected at 14 different production units. The exposure to wood dust at the industrial premises investigated has decreased from a relatively high level of 6.4 mg m-3 in 2001 to 1.0 mg-3 in 2013. The Swedish Occupational Exposure Limit (SOEL) of 2 mg m-3 may still be exceeded. Analysis of the temporal trend in soft wood production units revealed declines in exposure of 20.5% per annum. It is important that precautions are taken to protect workers from a hazardous exposure to wood dust at the premises as the SOEL of 2 mg m-3 at some occasions is still exceeded. Additional measurements of wood dust exposure should be carried out on a regular basis in wood pellet production units in Sweden as well in other countries. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Geo-spatial analysis of temporal trends of temperature and its extremes over India using daily gridded (1°×1°) temperature data of 1969-2005

NASA Astrophysics Data System (ADS)

Chakraborty, Abhishek; Seshasai, M. V. R.; Rao, S. V. C. Kameswara; Dadhwal, V. K.

2017-10-01

Daily gridded (1°×1°) temperature data (1969-2005) were used to detect spatial patterns of temporal trends of maximum and minimum temperature (monthly and seasonal), growing degree days (GDDs) over the crop-growing season ( kharif, rabi, and zaid) and annual frequencies of temperature extremes over India. The direction and magnitude of trends, at each grid level, were estimated using the Mann-Kendall statistics ( α = 0.05) and further assessed at the homogeneous temperature regions using a field significance test ( α=0.05). General warming trends were observed over India with considerable variations in direction and magnitude over space and time. The spatial extent and the magnitude of the increasing trends of minimum temperature (0.02-0.04 °C year-1) were found to be higher than that of maximum temperature (0.01-0.02 °C year-1) during winter and pre-monsoon seasons. Significant negative trends of minimum temperature were found over eastern India during the monsoon months. Such trends were also observed for the maximum temperature over northern and eastern parts, particularly in the winter month of January. The general warming patterns also changed the thermal environment of the crop-growing season causing significant increase in GDDs during kharif and rabi seasons across India. The warming climate has also caused significant increase in occurrences of hot extremes such as hot days and hot nights, and significant decrease in cold extremes such as cold days and cold nights.

Exploring Potential Reasons for the Temporal Trend in Dialysis-Requiring AKI in the United States

PubMed Central

McCulloch, Charles E.; Heung, Michael; Saran, Rajiv; Shahinian, Vahakn B.; Pavkov, Meda E.; Burrows, Nilka Ríos; Powe, Neil R.; Hsu, Chi-yuan

2016-01-01

Background and objectives The population incidence of dialysis-requiring AKI has risen substantially in the last decade in the United States, and factors associated with this temporal trend are not well known. Design, setting, participants, & measurements We conducted a retrospective cohort study using data from the Nationwide Inpatient Sample, a United States nationally representative database of hospitalizations from 2007 to 2009. We used validated International Classification of Diseases, Ninth Revision codes to identify hospitalizations with dialysis-requiring AKI and then, selected the diagnostic and procedure codes most highly associated with dialysis-requiring AKI in 2009. We applied multivariable logistic regression adjusting for demographics and used a backward selection technique to identify a set of diagnoses or a set of procedures that may be a driver for this changing risk in dialysis-requiring AKI. Results From 2007 to 2009, the population incidence of dialysis-requiring AKI increased by 11% per year (95% confidence interval, 1.07 to 1.16; P<0.001). Using backward selection, we found that the temporal trend in the six diagnoses, septicemia, hypertension, respiratory failure, coagulation/hemorrhagic disorders, shock, and liver disease, sufficiently and fully accounted for the temporal trend in dialysis-requiring AKI. In contrast, temporal trends in 15 procedures most commonly associated with dialysis-requiring AKI did not account for the increasing dialysis–requiring AKI trend. Conclusions The increasing risk of dialysis-requiring AKI among hospitalized patients in the United States was highly associated with the changing burden of six acute and chronic conditions but not with surgeries and procedures. PMID:26683890

Mortality from idiopathic pulmonary fibrosis: a temporal trend analysis in Brazil, 1979-2014

PubMed Central

Algranti, Eduardo; Saito, Cézar Akiyoshi; Silva, Diego Rodrigues Mendonça e; Carneiro, Ana Paula Scalia; Bussacos, Marco Antonio

2017-01-01

ABSTRACT Objective: To analyze mortality from idiopathic pulmonary fibrosis (IPF) in Brazil over the period 1979-2014. Methods: Microdata were extracted from the Brazilian National Ministry of Health Mortality Database. Only deaths for which the underlying cause was coded as International Classification of Diseases version 9 (ICD-9) 515 or 516.3 (until 1995) or as ICD version 10 (ICD-10) J84.1 (from 1996 onward) were included in our analysis. Standardized mortality rates were calculated for the 2010 Brazilian population. The annual trend in mortality rates was analyzed by joinpoint regression. We calculated risk ratios (RRs) by age group, time period of death, and gender, using a person-years denominator. Results: A total of 32,092 deaths were recorded in the study period. Standardized mortality rates trended upward, rising from 0.24/100,000 population in 1979 to 1.10/100,000 population in 2014. The annual upward trend in mortality rates had two inflection points, in 1992 and 2008, separating three distinct time segments with an annual growth of 2.2%, 6.8%, and 2.4%, respectively. The comparison of RRs for the age groups, using the 50- to 54-year age group as a reference, and for the study period, using 1979-1984 as a reference, were 16.14 (14.44-16.36) and 6.71 (6.34-7.12), respectively. Men compared with women had higher standardized mortality rates (per 100,000 person-years) in all age groups. Conclusion: Brazilian IPF mortality rates are lower than those of other countries, suggesting underdiagnosis or underreporting. The temporal trend is similar to those reported in the literature and is not explained solely by population aging. PMID:29340493

Long Term Precipitation Pattern Identification and Derivation of Non Linear Precipitation Trend in a Catchment using Singular Spectrum Analysis

NASA Astrophysics Data System (ADS)

Unnikrishnan, Poornima; Jothiprakash, Vinayakam

2017-04-01

Precipitation is the major component in the hydrologic cycle. Awareness of not only the total amount of rainfall pertaining to a catchment, but also the pattern of its spatial and temporal distribution are equally important in the management of water resources systems in an efficient way. Trend is the long term direction of a time series; it determines the overall pattern of a time series. Singular Spectrum Analysis (SSA) is a time series analysis technique that decomposes the time series into small components (eigen triples). This property of the method of SSA has been utilized to extract the trend component of the rainfall time series. In order to derive trend from the rainfall time series, we need to select components corresponding to trend from the eigen triples. For this purpose, periodogram analysis of the eigen triples have been proposed to be coupled with SSA, in the present study. In the study, seasonal data of England and Wales Precipitation (EWP) for a time period of 1766-2013 have been analyzed and non linear trend have been derived out of the precipitation data. In order to compare the performance of SSA in deriving trend component, Mann Kendall (MK) test is also used to detect trends in EWP seasonal series and the results have been compared. The result showed that the MK test could detect the presence of positive or negative trend for a significance level, whereas the proposed methodology of SSA could extract the non-linear trend present in the rainfall series along with its shape. We will discuss further the comparison of both the methodologies along with the results in the presentation.

Quantitative patterns of stylistic influence in the evolution of literature.

PubMed

Hughes, James M; Foti, Nicholas J; Krakauer, David C; Rockmore, Daniel N

2012-05-15

Literature is a form of expression whose temporal structure, both in content and style, provides a historical record of the evolution of culture. In this work we take on a quantitative analysis of literary style and conduct the first large-scale temporal stylometric study of literature by using the vast holdings in the Project Gutenberg Digital Library corpus. We find temporal stylistic localization among authors through the analysis of the similarity structure in feature vectors derived from content-free word usage, nonhomogeneous decay rates of stylistic influence, and an accelerating rate of decay of influence among modern authors. Within a given time period we also find evidence for stylistic coherence with a given literary topic, such that writers in different fields adopt different literary styles. This study gives quantitative support to the notion of a literary "style of a time" with a strong trend toward increasingly contemporaneous stylistic influence.

Spatiotemporal trend analysis of metal concentrations in sediments of a residential California stream with toxicity and regulatory implications.

PubMed

Hall, Lenwood W; Anderson, Ronald D; Killen, William D

2017-06-07

The objective of this study was to determine if concentrations of arsenic, cadmium, chromium, copper, lead, nickel and zinc measured in the sediments of a residential stream in California (Pleasant Grove Creek) have changed temporally or spatially from 2006 to 2016. Threshold Effect Levels (TELs), conservative ecological effects benchmarks, and exceedances for the seven metals were also evaluated over the 11-year time period to provide insight into potential metal toxicity to resident benthic communities. In addition, the bioavailability of metals in sediments was also determined by calculating Simultaneous Extracted Metal/Acid Volatle Sulfide (SEM/AVS) ratios to allow an additional assessment of toxicity. Regulatory implications of this data set and the role of metal toxicity are also discussed. Stream-wide temporal trend analysis showed no statistically significant trends for any of the metals. However, spatial analysis for several sites located near storm drains did show a significant increase for most metals over the 11-year period. TEL exceedances during the 7 years of sampling, spanning 2006-2016, were reported for all metals with the number of exceedances ranging from 47 for copper and zinc to 1 for lead. A spatial analysis showed that the highest number of TEL exceedances and the highest number of SEM/AVS ratios greater than one with at least one metal exceeding a TEL occurred at upstream sites. The potentially toxic metal concentrations reported in Pleasant Grove Creek should be used in the 303 (d) listing process for impaired water bodies in California.

Wavelet Analyses of Oil Prices, USD Variations and Impact on Logistics

NASA Astrophysics Data System (ADS)

Melek, M.; Tokgozlu, A.; Aslan, Z.

2009-07-01

This paper is related with temporal variations of historical oil prices and Dollar and Euro in Turkey. Daily data based on OECD and Central Bank of Turkey records beginning from 1946 has been considered. 1D-continuous wavelets and wavelet packets analysis techniques have been applied on data. Wavelet techniques help to detect abrupt changing's, increasing and decreasing trends of data. Estimation of variables has been presented by using linear regression estimation techniques. The results of this study have been compared with the small and large scale effects. Transportation costs of track show a similar variation with fuel prices. The second part of the paper is related with estimation of imports, exports, costs, total number of vehicles and annual variations by considering temporal variation of oil prices and Dollar currency in Turkey. Wavelet techniques offer a user friendly methodology to interpret some local effects on increasing trend of imports and exports data.

SPATIAL CHANGES IN THE ECOLOGICAL CONDITION OF LAKES ACROSS THE CONTERMINOUS UNITED STATES SINCE 2000

EPA Science Inventory

Much of the literature and attention on the analysis of ecological change is focused on detecting temporal trends at single sites. Of equal importance is the change in spatial condition across the landscape. For example, are there more hypereutrophic lakes in the U.S. now than th...

Variability of tornado occurrence over the continental United States since 1950

NASA Astrophysics Data System (ADS)

Guo, Li; Wang, Kaicun; Bluestein, Howard B.

2016-06-01

The United States experiences the most tornadoes of any country in the world. Given the catastrophic impact of tornadoes, concern has arisen regarding the variation in climatology of U.S. tornadoes under the changing climate. A recent study claimed that the temporal variability of tornado occurrence over the continental U.S. has increased since the 1970s. However, that study ignored the highly regionalized climatology of U.S. tornadoes. To address this issue, we examined the long-term trend of tornado temporal variability in each continental U.S. state. Based on the 64 year tornado records (1950-2013), we found that the trends in tornado temporal variability varied across the U.S., with only one third of the continental area or three out of 10 contiguous states (mostly from the Great Plains and Southeast, but where the frequency of occurrence of tornadoes is greater) displaying a significantly increasing trend. The other two-thirds area, where 60% of the U.S. tornadoes were reported (but the frequency of occurrence of tornadoes is less), however, showed a decreasing or a near-zero trend in tornado temporal variability. Furthermore, unlike the temporal variability alone, the combined spatial-temporal variability of U.S. tornado occurrence has remained nearly constant since 1950. Such detailed information on the climatological variability of U.S. tornadoes refines the claim of previous study and can be helpful for local mitigation efforts toward future tornado risks.

Improving FIA trend analysis through model-based estimation using landsat disturbance maps and the forest vegetation simulator

Treesearch

Sean P. Healey; Gretchen G. Moisen; Paul L. Patterson

2012-01-01

The Forest Inventory and Analysis (FIA) Program's panel system, in which 10-20 percent of the sample is measured in any given year, is designed to increase the currency of FIA reporting and its sensitivity to factors operating at relatively fine temporal scales. Now that much of the country has completed at least one measurement cycle over all panels, there is an...

Integrative Approach to Quality Assessment of Medical Journals Using Impact Factor, Eigenfactor, and Article Influence Scores

PubMed Central

Rizkallah, Jacques; Sin, Don D.

2010-01-01

Background Impact factor (IF) is a commonly used surrogate for assessing the scientific quality of journals and articles. There is growing discontent in the medical community with the use of this quality assessment tool because of its many inherent limitations. To help address such concerns, Eigenfactor (ES) and Article Influence scores (AIS) have been devised to assess scientific impact of journals. The principal aim was to compare the temporal trends in IF, ES, and AIS on the rank order of leading medical journals over time. Methods The 2001 to 2008 IF, ES, AIS, and number of citable items (CI) of 35 leading medical journals were collected from the Institute of Scientific Information (ISI) and the http://www.eigenfactor.org databases. The journals were ranked based on the published 2008 ES, AIS, and IF scores. Temporal score trends and variations were analyzed. Results In general, the AIS and IF values provided similar rank orders. Using ES values resulted in large changes in the rank orders with higher ranking being assigned to journals that publish a large volume of articles. Since 2001, the IF and AIS of most journals increased significantly; however the ES increased in only 51% of the journals in the analysis. Conversely, 26% of journals experienced a downward trend in their ES, while the rest experienced no significant changes (23%). This discordance between temporal trends in IF and ES was largely driven by temporal changes in the number of CI published by the journals. Conclusion The rank order of medical journals changes depending on whether IF, AIS or ES is used. All of these metrics are sensitive to the number of citable items published by journals. Consumers should thus consider all of these metrics rather than just IF alone in assessing the influence and importance of medical journals in their respective disciplines. PMID:20419115

High variability in spatial and temporal size-based trophodynamics of deep-sea fishes from the Mid-Atlantic Ridge elucidated by stable isotopes

NASA Astrophysics Data System (ADS)

Reid, William D. K.; Sweeting, Christopher J.; Wigham, Ben D.; McGill, Rona A. R.; Polunin, Nicholas V. C.

2013-12-01

Demersal fish play an important role in the deep-sea ecosystem by acting as a link to mobile food in the water column, consuming benthic fauna, breaking down large food parcels and dispersing organic matter over large areas. Poor diet resolution from stomach content analysis often impairs the ability to assess differences in inter- and intra-population trophodynamics and therefore understand resource partitioning among deep-sea fishes. Antimora rostrata (predator-scavenger), Coryphaenoides armatus (predator-scavenger), Coryphaenoides brevibarbis (predator) and Halosauropsis macrochir (predator) were collected from 3 stations on the Mid-Atlantic Ridge (MAR) in 2007 and 2009 to investigate trophic ecology using δ13C and δ15N. Variability in lipid-normalised δ13C (δ13Cn) and δ15N was explained by body length in all species but slope and significance of the isotope-length relationships varied both temporally and spatially. δ15N increases with length were observed in A. rostrata at all stations, C. brevibarbis and H. macrochir at one or more stations but were absent in C. armatus. δ13Cn increased with length in A. rostrata but the slope of δ13Cn-length relationships varied spatially and temporally in C. armatus and C. brevibarbis. The co-occurring δ13Cn and δ15N size-based trends in A. rostrata and H. macrochir suggested that size-based trends were a result of increasing trophic position. In C. armatus and C. brevibarbis the isotope-length trends were difficult to distinguish among trophic position increases, shifts in resource use i.e. benthic to pelagic or internal physiology. However, the overall strength, direction and significance of isotope-length trends varied temporally and spatially which suggested varying degrees of overlap in trophic ecology and feeding plasticity among these species.

Quantifying trends in disease impact to produce a consistent and reproducible definition of an emerging infectious disease.

PubMed

Funk, Sebastian; Bogich, Tiffany L; Jones, Kate E; Kilpatrick, A Marm; Daszak, Peter

2013-01-01

The proper allocation of public health resources for research and control requires quantification of both a disease's current burden and the trend in its impact. Infectious diseases that have been labeled as "emerging infectious diseases" (EIDs) have received heightened scientific and public attention and resources. However, the label 'emerging' is rarely backed by quantitative analysis and is often used subjectively. This can lead to over-allocation of resources to diseases that are incorrectly labelled "emerging," and insufficient allocation of resources to diseases for which evidence of an increasing or high sustained impact is strong. We suggest a simple quantitative approach, segmented regression, to characterize the trends and emergence of diseases. Segmented regression identifies one or more trends in a time series and determines the most statistically parsimonious split(s) (or joinpoints) in the time series. These joinpoints in the time series indicate time points when a change in trend occurred and may identify periods in which drivers of disease impact change. We illustrate the method by analyzing temporal patterns in incidence data for twelve diseases. This approach provides a way to classify a disease as currently emerging, re-emerging, receding, or stable based on temporal trends, as well as to pinpoint the time when the change in these trends happened. We argue that quantitative approaches to defining emergence based on the trend in impact of a disease can, with appropriate context, be used to prioritize resources for research and control. Implementing this more rigorous definition of an EID will require buy-in and enforcement from scientists, policy makers, peer reviewers and journal editors, but has the potential to improve resource allocation for global health.

Social determinants, their relationship with leprosy risk and temporal trends in a tri-border region in Latin America

PubMed Central

Arcoverde, Marcos Augusto Moraes; Ramos, Antônio Carlos Viera; Alves, Luana Seles; Berra, Thais Zamboni; Arroyo, Luiz Henrique; de Queiroz, Ana Angélica Rêgo; dos Santos, Danielle Talita; Belchior, Aylana de Souza; Alves, Josilene Dália; Pieri, Flávia Meneguetti; Silva-Sobrinho, Reinaldo Antônio; Pinto, Ione Carvalho; Tavares, Clodis Maria; Yamamura, Mellina; Frade, Marco Andrey Cipriani; Palha, Pedro Fredemir; Chiaravalloti-Neto, Francisco; Arcêncio, Ricardo Alexandre

2018-01-01

Background Brazil is the only country in Latin America that has adopted a national health system. This causes differences in access to health among Latin American countries and induces noticeable migration to Brazilian regions to seek healthcare. This phenomenon has led to difficulties in the control and elimination of diseases related to poverty, such as leprosy. The aim of this study was to evaluate social determinants and their relationship with the risk of leprosy, as well as to examine the temporal trend of its occurrence in a Brazilian municipality located on the tri-border area between Brazil, Paraguay and Argentina. Methods This ecological study investigated newly-diagnosed cases of leprosy between 2003 and 2015. Exploratory analysis of the data was performed through descriptive statistics. For spatial analysis, geocoding of the data was performed using spatial scan statistic techniques to obtain the Relative Risk (RR) for each census tract, with their respective 95% confidence intervals calculated. The Bivariate Moran I test, Ordinary Least Squares (OLS) and Geographically Weighted Regression (GWR) models were applied to analyze the spatial relationships of social determinants and leprosy risk. The temporal trend of the annual coefficient of new cases was obtained through the Prais-Winsten regression. A standard error of 5% was considered statistically significant (p < 0.05). Results Of the 840 new cases identified in the study, there was a predominance of females (n = 427, 50.8%), of white race/color (n = 685, 81.6%), age range 15 to 59 years (n = 624, 74.3%), and incomplete elementary education (n = 504, 60.0%). The results obtained from multivariate analysis revealed that the proportion of households with monthly nominal household income per capita greater than 1 minimum wage (β = 0.025, p = 0.036) and people of brown race (β = -0.101, p = 0.024) were statistically-significantly associated with risk of illness due to leprosy. These results also confirmed that social determinants and risk of leprosy were significantly spatially non-stationary. Regarding the temporal trend, a decrease of 4% (95% CI [-0.053, -0.033], p = 0.000) per year was observed in the rate of detection of new cases of leprosy. Conclusion The social determinants income and race/color were associated with the risk of leprosy. The study’s highlighting of these social determinants can contribute to the development of public policies directed toward the elimination of leprosy in the border region. PMID:29624595

Interpretation of tropospheric ozone variability in data with different vertical and temporal resolution

NASA Astrophysics Data System (ADS)

Petropavlovskikh, I. V.; Disterhoft, P.; Johnson, B. J.; Rieder, H. E.; Manney, G. L.; Daffer, W.

2012-12-01

This work attributes tropospheric ozone variability derived from the ground-based Dobson and Brewer Umkehr measurements and from ozone sonde data to local sources and transport. It assesses capability and limitations in both types of measurements that are often used to analyze long- and short-term variability in tropospheric ozone time series. We will address the natural and instrument-related contribution to the variability found in both Umkehr and sonde data. Validation of Umkehr methods is often done by intercomparisons against independent ozone measuring techniques such as ozone sounding. We will use ozone-sounding in its original and AK-smoothed vertical profiles for assessment of ozone inter-annual variability over Boulder, CO. We will discuss possible reasons for differences between different ozone measuring techniques and its effects on the derived ozone trends. Next to standard evaluation techniques we utilize a STL-decomposition method to address temporal variability and trends in the Boulder Umkehr data. Further, we apply a statistical modeling approach to the ozone data set to attribute ozone variability to individual driving forces associated with natural and anthropogenic causes. To this aim we follow earlier work applying a backward selection method (i.e., a stepwise elimination procedure out of a set of total 44 explanatory variables) to determine those explanatory variables which contribute most significantly to the observed variability. We will present also some results associated with completeness (sampling rate) of the existing data sets. We will also use MERRA (Modern-Era Retrospective analysis for Research and Applications) re-analysis results selected for Boulder location as a transfer function in understanding of the effects that the temporal sampling and vertical resolution bring into trend and ozone variability analysis. Analyzing intra-annual variability in ozone measurements over Boulder, CO, in relation to the upper tropospheric subtropical and polar jets, we will address the stratospheric and tropospheric intrusions in the middle latitude troposphere ozone field.

Vegetation Cover Analysis in Shaanxi Province of China Based on Grid Pixel Ternd Analysis and Stability Evaluation

NASA Astrophysics Data System (ADS)

Yue, H.; Liu, Y.

2018-04-01

As a key factor affecting the biogeochemical cycle of human existence, terrestrial vegetation is vulnerable to natural environment and human activities, with obvious temporal and spatial characteristics. The change of vegetation cover will affect the ecological balance and environmental quality to a great extent. Therefore, the research on the causes and influencing factors of vegetation cover has become the focus of attention of scholars at home and abroad. In the evolution of human activities and natural environment, the vegetation coverage in Shaanxi has changed accordingly. Using MODIS/NDVI 2000-2014 time series data, using the method of raster pixel trend analysis, stability evaluation, rescaled range analysis and correlation analysis, the climatic factors in Shaanxi province were studied in the near 15 years vegetation spatial and temporal variation and influence of vegetation NDVI changes. The results show that NDVI in Shaanxi province in the near 15 years increased by 0.081, the increase of NDVI in Northern Shaanxi was obvious, and negative growth was found in some areas of Guanzhong, southern Shaanxi NDVI overall still maintained at a high level; the trend of vegetation change in Shaanxi province has obvious spatial differences, most of the province is a slight tendency to improve vegetation, there are many obvious improvement areas in Northern Shaanxi Province. Guanzhong area vegetation area decreased, the small range of variation of vegetation in Shaanxi province; the most stable areas are mainly concentrated in the southern, southern Yanan, Yulin, Xi'an area of Weinan changed greatly; Shaanxi Province in recent 15 a, the temperature and precipitation have shown an increasing trend, and the vegetation NDVI is more closely related to the average annual rainfall, with increase of 0.48 °C/10 years and 69.5 mm per year.

Surface Subsidence Analysis by Multi-Temporal InSAR and GRACE: A Case Study in Beijing.

PubMed

Guo, Jiming; Zhou, Lv; Yao, Chaolong; Hu, Jiyuan

2016-09-14

The aim of this study was to investigate the relationship between surface subsidence and groundwater changes. To investigate this relationship, we first analyzed surface subsidence. This paper presents the results of a case study of surface subsidence in Beijing from 1 August 2007 to 29 September 2010. The Multi-temporal Interferometric Synthetic Aperture Radar (multi-temporal InSAR) technique, which can simultaneously detect point-like stable reflectors (PSs) and distributed scatterers (DSs), was used to retrieve the subsidence magnitude and distribution in Beijing using 18 ENVISAT ASAR images. The multi-temporal InSAR-derived subsidence was verified by leveling at an accuracy better than 5 mm/year. Based on the verified multi-temporal InSAR results, a prominent uneven subsidence was identified in Beijing. Specifically, most of the subsidence velocities in the downtown area were within 10 mm/year, and the largest subsidence was detected in Tongzhou, with velocities exceeding 140 mm/year. Furthermore, Gravity Recovery and Climate Experiment (GRACE) data were used to derive the groundwater change series and trend. By comparison with the multi-temporal InSAR-derived subsidence results, the long-term decreasing trend between groundwater changes and surface subsidence showed a relatively high consistency, and a significant impact of groundwater changes on the surface subsidence was identified. Additionally, the spatial distribution of the subsidence funnel was partially consistent with that of groundwater depression, i.e., the former possessed a wider range than the latter. Finally, the relationship between surface subsidence and groundwater changes was determined.

Surface Subsidence Analysis by Multi-Temporal InSAR and GRACE: A Case Study in Beijing

PubMed Central

Guo, Jiming; Zhou, Lv; Yao, Chaolong; Hu, Jiyuan

2016-01-01

The aim of this study was to investigate the relationship between surface subsidence and groundwater changes. To investigate this relationship, we first analyzed surface subsidence. This paper presents the results of a case study of surface subsidence in Beijing from 1 August 2007 to 29 September 2010. The Multi-temporal Interferometric Synthetic Aperture Radar (multi-temporal InSAR) technique, which can simultaneously detect point-like stable reflectors (PSs) and distributed scatterers (DSs), was used to retrieve the subsidence magnitude and distribution in Beijing using 18 ENVISAT ASAR images. The multi-temporal InSAR-derived subsidence was verified by leveling at an accuracy better than 5 mm/year. Based on the verified multi-temporal InSAR results, a prominent uneven subsidence was identified in Beijing. Specifically, most of the subsidence velocities in the downtown area were within 10 mm/year, and the largest subsidence was detected in Tongzhou, with velocities exceeding 140 mm/year. Furthermore, Gravity Recovery and Climate Experiment (GRACE) data were used to derive the groundwater change series and trend. By comparison with the multi-temporal InSAR-derived subsidence results, the long-term decreasing trend between groundwater changes and surface subsidence showed a relatively high consistency, and a significant impact of groundwater changes on the surface subsidence was identified. Additionally, the spatial distribution of the subsidence funnel was partially consistent with that of groundwater depression, i.e., the former possessed a wider range than the latter. Finally, the relationship between surface subsidence and groundwater changes was determined. PMID:27649183

TEMPORAL TRENDS IN THE HEALTH OF SOUTH FLORIDA CORAL REEFS

EPA Science Inventory

Barron, M.G., D.L. Santavy, L. MacLaughlin, E. Mueller, E. Peters, B. Quarles and J. Campbell. In press. Temporal Trends in the Health of South Florida Coral Reefs (Abstract). To be presented at the SETAC Fourth World Congress, 14-18 November 2004, Portland, OR. 1 p. (ERL,GB R100...

Trend analysis of Arctic sea ice extent

NASA Astrophysics Data System (ADS)

Silva, M. E.; Barbosa, S. M.; Antunes, Luís; Rocha, Conceição

2009-04-01

The extent of Arctic sea ice is a fundamental parameter of Arctic climate variability. In the context of climate change, the area covered by ice in the Arctic is a particularly useful indicator of recent changes in the Arctic environment. Climate models are in near universal agreement that Arctic sea ice extent will decline through the 21st century as a consequence of global warming and many studies predict a ice free Arctic as soon as 2012. Time series of satellite passive microwave observations allow to assess the temporal changes in the extent of Arctic sea ice. Much of the analysis of the ice extent time series, as in most climate studies from observational data, have been focussed on the computation of deterministic linear trends by ordinary least squares. However, many different processes, including deterministic, unit root and long-range dependent processes can engender trend like features in a time series. Several parametric tests have been developed, mainly in econometrics, to discriminate between stationarity (no trend), deterministic trend and stochastic trends. Here, these tests are applied in the trend analysis of the sea ice extent time series available at National Snow and Ice Data Center. The parametric stationary tests, Augmented Dickey-Fuller (ADF), Phillips-Perron (PP) and the KPSS, do not support an overall deterministic trend in the time series of Arctic sea ice extent. Therefore, alternative parametrizations such as long-range dependence should be considered for characterising long-term Arctic sea ice variability.

Tweet for health: using an online social network to examine temporal trends in weight loss-related posts.

PubMed

Turner-McGrievy, Gabrielle M; Beets, Michael W

2015-06-01

Few studies have used social networking sites to track temporal trends in health-related posts, particularly around weight loss. To examine the temporal relationship of Twitter messages about weight loss over 1 year (2012). Temporal trends in #weightloss mentions and #fitness, #diet, and #health tweets which also had the word "weight" in them were examined using three a priori time periods: (1) holidays: pre-winter holidays, holidays, and post-holidays; (2) Season: winter and summer; and (3) New Year's: pre-New Year's and post-New Year's. Regarding #weightloss, there were 145 (95 % CI 79, 211) more posts/day during holidays and 143 (95 % CI 76, 209) more posts/day after holidays as compared to 480 pre-holiday posts/day; 232 (95 % CI 178, 286) more posts/day during the winter versus summer (441 posts/day); there was no difference in posts around New Year's. Examining social networks for trends in health-related posts may aid in timing interventions when individuals are more likely to be discussing weight loss.

Tracking contaminants in seabirds of Arctic Canada: temporal and spatial insights.

PubMed

Mallory, Mark L; Braune, Birgit M

2012-07-01

Levels and trends of persistent organic pollutants and trace elements in seabirds breeding in the vast Canadian Arctic have been monitored since 1975. Data from this monitoring have indicated both spatial and temporal variation across the region, attributable in part to differences in species' diets, differences in regional deposition patterns, and unidirectional trends in contaminants reaching this area from emissions in temperate and tropical areas to the south. Seabird tissues have served as effective biomonitors to examine this variation, and national and international collaboration in this monitoring effort has promoted valuable synthetic assessments of spatial and temporal patterns in Arctic contaminants. Here we review the history of the monitoring program, the critical role played by Environment Canada's National Wildlife Specimen Bank, and we summarize important spatial and temporal trends in various contaminants in Canadian Arctic seabirds. Copyright © 2012 Elsevier Ltd. All rights reserved.

Quantile regression and clustering analysis of standardized precipitation index in the Tarim River Basin, Xinjiang, China

NASA Astrophysics Data System (ADS)

Yang, Peng; Xia, Jun; Zhang, Yongyong; Han, Jian; Wu, Xia

2017-11-01

Because drought is a very common and widespread natural disaster, it has attracted a great deal of academic interest. Based on 12-month time scale standardized precipitation indices (SPI12) calculated from precipitation data recorded between 1960 and 2015 at 22 weather stations in the Tarim River Basin (TRB), this study aims to identify the trends of SPI and drought duration, severity, and frequency at various quantiles and to perform cluster analysis of drought events in the TRB. The results indicated that (1) both precipitation and temperature at most stations in the TRB exhibited significant positive trends during 1960-2015; (2) multiple scales of SPIs changed significantly around 1986; (3) based on quantile regression analysis of temporal drought changes, the positive SPI slopes indicated less severe and less frequent droughts at lower quantiles, but clear variation was detected in the drought frequency; and (4) significantly different trends were found in drought frequency probably between severe droughts and drought frequency.

Analyzing spatial and temporal trends in Aboveground Biomass within the Acadian New England Forests using the complete Landsat Archive

NASA Astrophysics Data System (ADS)

Kilbride, J. B.; Fraver, S.; Ayrey, E.; Weiskittel, A.; Braaten, J.; Hughes, J. M.; Hayes, D. J.

2017-12-01

Forests within the New England states and Canadian Maritime provinces, here described as the Acadian New England (ANE) forests, have undergone substantial disturbances due to insect, fire, and anthropogenic factors. Through repeated satellite observations captures by USGS's Landsat program, 45 years of disturbance information can be incorporated into modeling efforts to better understand the spatial and temporal trends in forest above ground biomass (AGB). Using Google's Earth Engine, annual mosaics were developed for the ANE study area and then disturbance and recovery metrics were developed using the temporal segmentation algorithm VeRDET. Normalization procedures were developed to incorporate the Landsat Multispectral Scanner (MSS, 1972 - 1985) data alongside the modern era of Landsat Thematic Mapper (TM, 1984-2013), Enhanced Thematic Mapper plus (ETM+, 1999 - present), and Operational Land Imager (OLI, 2013- present) data products. This has enabled the creation of a dataset with an unprecedented spatial and temporal view of forest landscape change. Model training was performed using was the Forest Inventory Analysis (FIA) and New Brunswick Permanent Sample Plot data datasets. Modeling was performed using parametric techniques such as mixed effects models and non-parametric techniques such as k-NN imputation and generalized boosted regression. We compare the biomass estimate and model accuracy to other inventory and modeling studies produced within this study area. The spatial and temporal patterns of stock changes are analyzed against resource policy, land ownership changes, and forest management.

Detecting drought and human-induced land degradation using time series trend analysis in Northeastern Brazil drylands

NASA Astrophysics Data System (ADS)

Mariano, D. A.; Costa dos Santos, C. A.; Wardlow, B.

2017-12-01

Land degradation (LD) is one of the most catastrophic outcomes of long-lasting drought events and anthropogenic activities. Assessing climate and human-induced impacts on land can provide information for decision makers to mitigate the effects associated to thereof. The Northeastern region of Brazil (NEB) is the most populous dryland on the planet, making it a highly vulnerable ecosystem especially when considering the lingering drought that started in 2012. The present work consisted on detecting trends in biomass [gross primary productivity (GPP)] and albedo anomalies as indicators of land degradation in NEB. Both GPP and albedo data were derived from MODIS/Terra sensor at 8-day temporal and 500m spatial resolutions. For precipitation z-scores, we relied on CHIRPS-v2 10-day temporal and 5km spatial resolution data. For detecting trends, we applied linear regressions on time series of MODIS GPP and albedo images. Trend analysis was performed for the periods ranging from 2002-2012 (no severe droughts) and 2002-2016 (includes the last drought). The first analysis highlights the human-induced LD whereas the last detected drought induced LD. About 4.5% of the area undergone human-induced degradation whereas drought was responsible for 13%, although, not mutually exclusive. As reported in the literature and official data, grazing intensification was the main driver for human-induced LD. GPP trends were more pronounced and had a stronger signal than albedo, thus, is considered more efficient on mapping LD. Finally, the effects of LD on evapotranspiration anomalies [evaporative stress index (ESI)] were assessed as a way to link it to the hydrological cycle. GPP and ET relations are very site-specific; thus, we found that these variables are highly correlated in regions where LD was intense. We conclude that, in fact, drought led to severe LD in NEB and, the degradation cycle has a positive feedback derived from ET reduction resulting in an increased net moisture deficit. The study warns of the desertification risk that NEB is facing and the need for the authorities to take action to stop these trends.

Evaluating the spatiotemporal variations of water budget across China over 1951-2006 using IBIS model

USGS Publications Warehouse

Zhu, Q.; Jiang, H.; Liu, J.; Wei, X.; Peng, C.; Fang, X.; Liu, S.; Zhou, G.; Yu, S.; Ju, W.

2010-01-01

The Integrated Biosphere Simulator is used to evaluate the spatial and temporal patterns of the crucial hydrological variables [run-off and actual evapotranspiration (AET)] of the water balance across China for the period 1951–2006 including a precipitation analysis. Results suggest three major findings. First, simulated run-off captured 85% of the spatial variability and 80% of the temporal variability for 85 hydrological gauges across China. The mean relative errors were within 20% for 66% of the studied stations and within 30% for 86% of the stations. The Nash–Sutcliffe coefficients indicated that the quantity pattern of run-off was also captured acceptably except for some watersheds in southwestern and northwestern China. The possible reasons for underestimation of run-off in the Tibetan plateau include underestimation of precipitation and uncertainties in other meteorological data due to complex topography, and simplified representations of the soil depth attribute and snow processes in the model. Second, simulated AET matched reasonably with estimated values calculated as the residual of precipitation and run-off for watersheds controlled by the hydrological gauges. Finally, trend analysis based on the Mann–Kendall method indicated that significant increasing and decreasing patterns in precipitation appeared in the northwest part of China and the Yellow River region, respectively. Significant increasing and decreasing trends in AET were detected in the Southwest region and the Yangtze River region, respectively. In addition, the Southwest region, northern China (including the Heilongjiang, Liaohe, and Haihe Basins), and the Yellow River Basin showed significant decreasing trends in run-off, and the Zhemin hydrological region showed a significant increasing trend.

Analysis of spatial-temporal heterogeneity in remotely sensed aerosol properties observed during 2005-2015 over three countries along the Gulf of Guinea Coast in Southern West Africa

NASA Astrophysics Data System (ADS)

Aklesso, Mangamana; Kumar, K. Raghavendra; Bu, Lingbing; Boiyo, Richard

2018-06-01

In the present study, the spatial-temporal distribution and estimation of trends of different aerosol optical properties, and related impact factors were investigated over three countries: Ghana, Togo, and Benin along the Gulf of Guinea Coast in Southern West Africa (SWA). For this purpose, long-term satellite derived aerosol optical properties (aerosol optical depth at 550 nm; AOD550, Ångström exponent at 470-660 nm; AE470-660, and absorption aerosol index; AAI) retrieved from the Moderate-resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI) during January 2005-December 2015 were utilized. The annual mean spatial distribution of AOD550 was found to be high (>0.55) over the southern coastal area, moderate-to-high (0.35-0.55) over the central, and low (<0.35) over northern parts of the study domain. The seasonal mean variations showed high (low) values of AOD550 and AAI during the Harmattan or dry (wet) season. Whereas, low (high) AE470-660 values were characterized during the Harmattan (wet) season. Linear trend analysis revealed a decreasing trend in AOD550 and AAI, and increasing trend in AE470-660. Further, an investigation on the potential drivers to AOD distribution over the SWA revealed that precipitation, NDVI, and terrain were negatively correlated with AOD. Finally, the HYSPLIT derived back trajectory analyses revealed diverse transport pathways originated from the North Atlantic Ocean, Sahara Desert, and Nigeria along with locally generated aerosols.

Total ozone trend significance from space time variability of daily Dobson data

NASA Technical Reports Server (NTRS)

Wilcox, R. W.

1981-01-01

Estimates of standard errors of total ozone time and area means, as derived from ozone's natural temporal and spatial variability and autocorrelation in middle latitudes determined from daily Dobson data are presented. Assessing the significance of apparent total ozone trends is equivalent to assessing the standard error of the means. Standard errors of time averages depend on the temporal variability and correlation of the averaged parameter. Trend detectability is discussed, both for the present network and for satellite measurements.

Temporal variability in wind-wave climate and its validation with ESSO-NIOT wave atlas for the head Bay of Bengal

NASA Astrophysics Data System (ADS)

Patra, Anindita; Bhaskaran, Prasad K.

2017-08-01

The head Bay region bordering the northern Bay of Bengal is a densely populated area with a complex geomorphologic setting, and highly vulnerable to extreme water levels along with other factors like sea level rise and impact of tropical cyclones. The influence of climate change on wind-wave regime from this region of Bay of Bengal is not known well and that requires special attention, and there is a need to perform its long-term assessment for societal benefits. This study provides a comprehensive analysis on the temporal variability in domain averaged wind speed, significant wave height (SWH) utilizing satellite altimeter data (1992-2012) and mean wave period using ECMWF reanalysis products ERA-Interim (1992-2012) and ERA-20C (1992-2010) over this region. The SWH derived from WAVEWATCH III (WW3) model along with the ERA-Interim reanalysis supplements the observed variability in satellite altimeter observations. Further, the study performs an extensive error estimation of SWH and mean wave period with ESSO-NIOT wave atlas that shows a high degree of under-estimation in the wave atlas mean wave period. Annual mean and wind speed maxima from altimeter show an increasing trend, and to a lesser extent in the SWH. Interestingly, the estimated trend is higher for maxima compared to the mean conditions. Analysis of decadal variability exhibits an increased frequency of higher waves in the present decade compared to the past. Linear trend analysis show significant upswing in spatially averaged ERA-20C mean wave period, whereas the noticed variations are marginal in the ERA-Interim data. A separate trend analysis for the wind-seas, swell wave heights and period from ERA-20C decipher the fact that distant swells governs the local wind-wave climatology over the head Bay region, and over time the swell activity have increased in this region.

A population-based analysis of temporal perioperative complication rates after minimally invasive radical prostatectomy.

PubMed

Schmitges, Jan; Trinh, Quoc-Dien; Abdollah, Firas; Sun, Maxine; Bianchi, Marco; Budäus, Lars; Zorn, Kevin; Perotte, Paul; Schlomm, Thorsten; Haese, Alexander; Montorsi, Francesco; Menon, Mani; Graefen, Markus; Karakiewicz, Pierre I

2011-09-01

Existing population-based reports on complication rates after minimally invasive radical prostatectomy (MIRP) did not address temporal trends. To examine contemporary temporal trends in perioperative MIRP outcomes. Between 2001 and 2007, 4387 patients undergoing MIRP were identified using the Nationwide Inpatient Sample. To examine the rates and trends of intraoperative and postoperative complications, transfusion rates, length of stay in excess of the median, and in-hospital mortality. We tested the effect of the late (2006-2007) versus the early (2001-2005) study period on all outcomes using multivariable logistic regression models controlled for clustering among hospitals. Intraoperative and postoperative complications decreased from 7.0% to 0.8% (p < 0.001) and from 28.5% to 8.7% (p < 0.001), respectively. Transfusion rates decreased from 3.5% to 2.1% (p = 0.3). Hospital length of stay >2 d decreased from 56% to 15% (p < 0.001). In multivariable analyses, intraoperative (odds ratio [OR]: 0.41; p = 0.002) and postoperative (OR: 0.65; p = 0.007) complications were less frequent in the late versus the early study period. Late study period patients were less likely to stay >2 d than early study period patients (OR: 0.34; p > 0.001). Limitations of these findings include the lack of adjustment for several patient variables including disease characteristics, surgeon variables including surgeon caseload, and the restriction to in-hospital events. Our analyses demonstrate that in-hospital complication rates and length of stay after MIRP decreased over time. This implies that temporal differences specific to complication rates after MIRP must be considered when comparisons are made with other radical prostatectomy techniques. Copyright © 2011 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Comparison of temporal trends in ambient and compliance trace element and PCB data in pool 2 of the Mississippi River, USA, 1985-1995

USGS Publications Warehouse

Anderson, J.; Perry, J.

1999-01-01

The Intergovernmental Task Force on Monitoring has suggested studies on ambient (in-stream) and compliance (wastewater) data to determine if monitoring can be reduced locally or nationally. The similarity in temporal trends between retrospective ambient and compliance water-quality data collected from Pool 2 of the Mississippi River, USA, was determined for 1985–1995. Constituents studied included the following trace elements: arsenic (As), cadmium (Cd), chromium (Cr), hexavalent chromium (Cr61), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), selenium (Se), zinc (Zn), and polychlorinated biphenyls (PCBs). Water-column, bed-sediment, and fish-tissue (fillets) data collected by five government agencies comprised the ambient data set; effluent data from five registered facilities comprised the compliance data set. The nonparametric MannKendall trend test indicated that 33% of temporal trends in all data were statistically significant (P , 0.05). Possible reasons for this were low sample sizes, and a high percentage of samples below the analytical detection limit. Trends in compliance data were more distinct; most trace elements decreased significantly, probably due to improvements in wastewater treatment. Seven trace elements (Cr, Cd, Cu, Pb, Hg, Ni, and Zn) had statistically significant decreases in wastewater and portions of either or both ambient water and bed sediment. No trends were found in fish tissue. Inconsistency in trends between ambient and compliance data were often found for individual constituents, making overall similarity between the data sets difficult to determine. Logistical differences in monitoring programs, such as varying field and laboratory methods among agencies, made it difficult to assess ambient temporal trends.

Trends in hydrometeorological conditions and stream water organic carbon in boreal forested catchments.

PubMed

Sarkkola, Sakari; Koivusalo, Harri; Laurén, Ari; Kortelainen, Pirkko; Mattsson, Tuija; Palviainen, Marjo; Piirainen, Sirpa; Starr, Mike; Finér, Leena

2009-12-15

Temporal trends in stream water total organic carbon (TOC) concentration and export were studied in 8 forested headwater catchments situated in eastern Finland. The Seasonal Kendall test was conducted to identify the trends and a mixed model regression analysis was used to describe how catchment characteristics and hydrometeorological variables (e.g. precipitation, air and stream water temperatures, and atmospheric deposition) related to the variation in the concentration and export of stream water TOC. The 8 catchments varied in size from 29 to 494 ha and in the proportion of peatland they contained, from 8 to 70%. Runoff and TOC concentration were monitored for 15-29 years (1979-2006). Trends and variation in TOC levels were analysed from annual and seasonal time series. Mean annual TOC concentration increased significantly in seven of the eight catchments. The trends were the strongest in spring and most apparent during the last decade of the study period. The slopes of the trends were generally smaller than the variation in TOC concentration between years and seasons and between catchments. The annual TOC export showed no clear trends and values were largely determined by the temporal variability in runoff. Annual runoff showed a decreasing trend in two of the eight catchments. Mean annual air and stream water temperatures showed increasing trends, most clearly seen in the summer and autumn series. According to our modeling results, stream water temperature, precipitation and peatland percentage were the most important variables explaining annual and most seasonal TOC concentrations. The atmospheric deposition of SO4, NH4, and NO3 decreased significantly over the study period, but no significant link with TOC concentration was found. Precipitation was the main hydrometeorological driver of the TOC export. We concluded that stream water TOC concentrations and exports are mainly driven by catchment characteristics and hydrometeorological factors rather than trends in atmospheric acid deposition.

Effect of Dosimetric Factors on Occurrence and Volume of Temporal Lobe Necrosis Following Intensity Modulated Radiation Therapy for Nasopharyngeal Carcinoma: A Case-Control Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Xin; Ou, Xiaomin; Xu, Tingting

Purpose: To determine dosimetric risk factors for the occurrence of temporal lobe necrosis (TLN) among nasopharyngeal carcinoma (NPC) patients treated with intensity modulated radiation therapy (IMRT) and to investigate the impact of dose-volume histogram (DVH) parameters on the volume of TLN lesions (V-N). Methods and Materials: Forty-three NPC patients who had developed TLN following IMRT and 43 control subjects free of TLN were retrospectively assessed. DVH parameters included maximum dose (Dmax), minimum dose (Dmin), mean dose (Dmean), absolute volumes receiving specific dose (Vds) from 20 to 76 Gy (V20-V76), and doses covering certain volumes (Dvs) from 0.25 to 6.0 cm{sup 3} (D0.25-D6.0).more » V-Ns were quantified with axial magnetic resonance images. Results: DVH parameters were ubiquitously higher in temporal lobes with necrosis than in healthy temporal lobes. Increased Vds and Dvs were significantly associated with higher risk of TLN occurrence (P<.05). In particular, Vds at a dose of ≥70 Gy were found with the highest odds ratios. A common increasing trend was detected between V-N and DVH parameters through trend tests (P for trend of <.05). Linear regression analysis showed that V45 had the strongest predictive power for V-N (adjusted R{sup 2} = 0.305, P<.0001). V45 of <15.1 cm{sup 3} was relatively safe as the dose constraint for preventing large TLN lesions with V-N of >5 cm{sup 3}. Conclusions: Dosimetric parameters are significantly associated with TLN occurrence and the extent of temporal lobe injury. To better manage TLN, it would be important to avoid both focal high dose and moderate dose delivered to a large area in TLs.« less

Global Incidence and Mortality for Prostate Cancer: Analysis of Temporal Patterns and Trends in 36 Countries.

PubMed

Wong, Martin C S; Goggins, William B; Wang, Harry H X; Fung, Franklin D H; Leung, Colette; Wong, Samuel Y S; Ng, Chi Fai; Sung, Joseph J Y

2016-11-01

Prostate cancer (PCa) is a leading cause of mortality and morbidity globally, but its specific geographic patterns and temporal trends are under-researched. To test the hypotheses that PCa incidence is higher and PCa mortality is lower in countries with higher socioeconomic development, and that temporal trends for PCa incidence have increased while mortality has decreased over time. Data on age-standardized incidence and mortality rates in 2012 were retrieved from the GLOBOCAN database. Temporal patterns were assessed for 36 countries using data obtained from Cancer incidence in five continents volumes I-X and the World Health Organization mortality database. Correlations between incidence or mortality rates and socioeconomic indicators (human development index [HDI] and gross domestic product [GDP]) were evaluated. The average annual percent change in PCa incidence and mortality in the most recent 10 yr according to join-point regression. Reported PCa incidence rates varied more than 25-fold worldwide in 2012, with the highest incidence rates observed in Micronesia/Polynesia, the USA, and European countries. Mortality rates paralleled the incidence rates except for Africa, where PCa mortality rates were the highest. Countries with higher HDI (r=0.58) and per capita GDP (r=0.62) reported greater incidence rates. According to the most recent 10-yr temporal data available, most countries experienced increases in incidence, with sharp rises in incidence rates in Asia and Northern and Western Europe. A substantial reduction in mortality rates was reported in most countries, except in some Asian countries and Eastern Europe, where mortality increased. Data in regional registries could be underestimated. PCa incidence has increased while PCa mortality has decreased in most countries. The reported incidence was higher in countries with higher socioeconomic development. The incidence of prostate cancer has shown high variations geographically and over time, with smaller variations in mortality. Copyright © 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.

A PRINCIPAL COMPONENT ANALYSIS OF THE CLEAN AIR STATUS AND TRENDS NETWORK (CASTNET) AIR CONCENTRATION DATA

EPA Science Inventory

The spatial and temporal variability of ambient air concentrations of SO₂, SO₄^2-, NO₃, HNO₃, and NH₄⁺ obtained from EPA's CASTNet was examined using an objective, statistically based technique...

Exploring space-time structure of human mobility in urban space

NASA Astrophysics Data System (ADS)

Sun, J. B.; Yuan, J.; Wang, Y.; Si, H. B.; Shan, X. M.

2011-03-01

Understanding of human mobility in urban space benefits the planning and provision of municipal facilities and services. Due to the high penetration of cell phones, mobile cellular networks provide information for urban dynamics with a large spatial extent and continuous temporal coverage in comparison with traditional approaches. The original data investigated in this paper were collected by cellular networks in a southern city of China, recording the population distribution by dividing the city into thousands of pixels. The space-time structure of urban dynamics is explored by applying Principal Component Analysis (PCA) to the original data, from temporal and spatial perspectives between which there is a dual relation. Based on the results of the analysis, we have discovered four underlying rules of urban dynamics: low intrinsic dimensionality, three categories of common patterns, dominance of periodic trends, and temporal stability. It implies that the space-time structure can be captured well by remarkably few temporal or spatial predictable periodic patterns, and the structure unearthed by PCA evolves stably over time. All these features play a critical role in the applications of forecasting and anomaly detection.

Temporal Variability in the Deglutition Literature

PubMed Central

Molfenter, Sonja M.; Steele, Catriona M.

2013-01-01

A literature review was conducted on temporal measures of swallowing in healthy individuals with the purpose of determining the degree of variability present in such measures within the literature. A total of 46 studies that met inclusion criteria were reviewed. The definitions and descriptive statistics for all reported temporal parameters were compiled for meta-analysis. In total, 119 different temporal parameters were found in the literature. The three most-frequently occurring durational measures were: UES opening, laryngeal closure and hyoid movement. The three most-frequently occurring interval measures were: stage transition duration, pharyngeal transit time and duration from laryngeal closure to UES opening. Subtle variations in operational definitions across studies were noted, making the comparison of data challenging. Analysis of forest plots compiling descriptive statistical data (means and 95% confidence intervals) across studies revealed differing degrees of variability across durations and intervals. Two parameters (UES opening duration and the laryngeal-closure-to-UES-opening interval) demonstrated the least variability, reflected by small ranges for mean values and tight confidence intervals. Trends emerged for factors of bolus size and participant age for some variables. Other potential sources of variability are discussed. PMID:22366761

Comparison of future and base precipitation anomalies by SimCLIM statistical projection through ensemble approach in Pakistan

NASA Astrophysics Data System (ADS)

Amin, Asad; Nasim, Wajid; Mubeen, Muhammad; Kazmi, Dildar Hussain; Lin, Zhaohui; Wahid, Abdul; Sultana, Syeda Refat; Gibbs, Jim; Fahad, Shah

2017-09-01

Unpredictable precipitation trends have largely influenced by climate change which prolonged droughts or floods in South Asia. Statistical analysis of monthly, seasonal, and annual precipitation trend carried out for different temporal (1996-2015 and 2041-2060) and spatial scale (39 meteorological stations) in Pakistan. Statistical downscaling model (SimCLIM) was used for future precipitation projection (2041-2060) and analyzed by statistical approach. Ensemble approach combined with representative concentration pathways (RCPs) at medium level used for future projections. The magnitude and slop of trends were derived by applying Mann-Kendal and Sen's slop statistical approaches. Geo-statistical application used to generate precipitation trend maps. Comparison of base and projected precipitation by statistical analysis represented by maps and graphical visualization which facilitate to detect trends. Results of this study projects that precipitation trend was increasing more than 70% of weather stations for February, March, April, August, and September represented as base years. Precipitation trend was decreased in February to April but increase in July to October in projected years. Highest decreasing trend was reported in January for base years which was also decreased in projected years. Greater variation in precipitation trends for projected and base years was reported in February to April. Variations in projected precipitation trend for Punjab and Baluchistan highly accredited in March and April. Seasonal analysis shows large variation in winter, which shows increasing trend for more than 30% of weather stations and this increased trend approaches 40% for projected precipitation. High risk was reported in base year pre-monsoon season where 90% of weather station shows increasing trend but in projected years this trend decreased up to 33%. Finally, the annual precipitation trend has increased for more than 90% of meteorological stations in base (1996-2015) which has decreased for projected year (2041-2060) up to 76%. These result revealed that overall precipitation trend is decreasing in future year which may prolonged the drought in 14% of weather stations under study.

Trend analysis of air temperature and precipitation time series over Greece: 1955-2010

NASA Astrophysics Data System (ADS)

Marougianni, G.; Melas, D.; Kioutsioukis, I.; Feidas, H.; Zanis, P.; Anandranistakis, E.

2012-04-01

In this study, a database of air temperature and precipitation time series from the network of Hellenic National Meteorological Service has been developed in the framework of the project GEOCLIMA, co-financed by the European Union and Greek national funds through the Operational Program "Competitiveness and Entrepreneurship" of the Research Funding Program COOPERATION 2009. Initially, a quality test was applied to the raw data and then missing observations have been imputed with a regularized, spatial-temporal expectation - maximization algorithm to complete the climatic record. Next, a quantile - matching algorithm was applied in order to verify the homogeneity of the data. The processed time series were used for the calculation of temporal annual and seasonal trends of air temperature and precipitation. Monthly maximum and minimum surface air temperature and precipitation means at all available stations in Greece were analyzed for temporal trends and spatial variation patterns for the longest common time period of homogenous data (1955 - 2010), applying the Mann-Kendall test. The majority of the examined stations showed a significant increase in the summer maximum and minimum temperatures; this could be possibly physically linked to the Etesian winds, because of the less frequent expansion of the low over the southeastern Mediterranean. Summer minimum temperatures have been increasing at a faster rate than that of summer maximum temperatures, reflecting an asymmetric change of extreme temperature distributions. Total annual precipitation has been significantly decreased at the stations located in western Greece, as well as in the southeast, while the remaining areas exhibit a non-significant negative trend. This reduction is very likely linked to the positive phase of the NAO that resulted in an increase in the frequency and persistence of anticyclones over the Mediterranean.

Evaluation of non-stationarity of floods in the Northeastern and Upper Midwest United States

NASA Astrophysics Data System (ADS)

Dhakal, N.; Palmer, R. N.

2017-12-01

Climate change is likely to impact precipitation as well as snow accumulation and melt in the Northeastern and Upper Midwest Unites States, ultimately affecting the quantity and seasonal distribution of streamflow. Such information is crucial for flood protection polices for example for regional flood frequency analysis. The objective of this study is to analyze seasonality and magnitude of long-term daily annual maximum streamflow (AMF) records and its changes for 158 sites in Northeastern and Upper Midwest Unites States. Temporal trends were analyzed based on two 30-year blocks (1951-1980 and 1981-2010) of AMF. Seasonality is assessed based on nonparametric directional/circular statistical method that allows for an adaptive estimation of seasonal density. The results for temporal change in seasonality showed mixed pattern/trend across the stations. While for majority of the stations, the distribution of AMF timing is strongly unimodal (concentrated around Spring season) for the earlier time period, the strength in the modes have gotten weaker during the recent time period for a number of stations along the coastal states indicating the emergence of multiple modes and change in seasonality therein. Assessment of the temporal change in magnitude of AMF based on the Mann-Kendall nonparametric test shows that majority of the stations do not show significant increasing or decreasing trend for either time period. It is also observed that comparatively more stations show increasing trends in magnitude based on AMF from earlier time period and most of these stations are coastal sites concentrated in the southeastern part of the region. Our study focused on both seasonality and magnitude of AMF has important implications for flood management and mitigation.

Spatio-Temporal Analysis of Trends and periodicities of regional drought projections in India

NASA Astrophysics Data System (ADS)

Gupta, Vivek; Jain, Manoj Kumar

2017-04-01

Climate change is believed to be altering the hydrologic cycle of different regions worldwide. This may alter the occurrence and distribution of extreme events such as droughts and floods. India is one of the most drought affected country, it is therefore important to understand spatiotemporal variation of droughts in future due to climate change. In this paper, we have analyzed the spatiotemporal projections of droughts over India for 21st century using Global Climate Model (GCM) precipitation projections of ESM2G model under two Representative Concentration Pathways (RCP) namely, RCP 4.5 and RCP 8.5. K-means Clustering algorithm has been exploited to obtain homogeneous precipitation region in India for regional drought analysis. Further, temporal analysis of projected annual minimum SPI for year 2006 to 2100 has been performed for different homogeneous regions obtained using cluster analysis. Trend analysis of annual minimum SPI series has also been performed using Mann-Kendall and Sen's slope method. Furthermore, periodicity in SPI series have been examined using wavelet periodogram analysis. Findings of this paper suggest that major drought events for Northeastern and Southern India are likely to occur in second half of the 21st century while for all other parts of India, most of the major drought events are expected in first half of the 21st century. Also, wavelet periodicity analysis indicates inter-annual periodicities of projected droughts between 3 to 9.5 years in different regions of India.

Hierarchical Bayesian Spatio–Temporal Analysis of Climatic and Socio–Economic Determinants of Rocky Mountain Spotted Fever

PubMed Central

Raghavan, Ram K.; Goodin, Douglas G.; Neises, Daniel; Anderson, Gary A.; Ganta, Roman R.

2016-01-01

This study aims to examine the spatio-temporal dynamics of Rocky Mountain spotted fever (RMSF) prevalence in four contiguous states of Midwestern United States, and to determine the impact of environmental and socio–economic factors associated with this disease. Bayesian hierarchical models were used to quantify space and time only trends and spatio–temporal interaction effect in the case reports submitted to the state health departments in the region. Various socio–economic, environmental and climatic covariates screened a priori in a bivariate procedure were added to a main–effects Bayesian model in progressive steps to evaluate important drivers of RMSF space-time patterns in the region. Our results show a steady increase in RMSF incidence over the study period to newer geographic areas, and the posterior probabilities of county-specific trends indicate clustering of high risk counties in the central and southern parts of the study region. At the spatial scale of a county, the prevalence levels of RMSF is influenced by poverty status, average relative humidity, and average land surface temperature (>35°C) in the region, and the relevance of these factors in the context of climate–change impacts on tick–borne diseases are discussed. PMID:26942604

Hierarchical Bayesian Spatio-Temporal Analysis of Climatic and Socio-Economic Determinants of Rocky Mountain Spotted Fever.

PubMed

Raghavan, Ram K; Goodin, Douglas G; Neises, Daniel; Anderson, Gary A; Ganta, Roman R

2016-01-01

This study aims to examine the spatio-temporal dynamics of Rocky Mountain spotted fever (RMSF) prevalence in four contiguous states of Midwestern United States, and to determine the impact of environmental and socio-economic factors associated with this disease. Bayesian hierarchical models were used to quantify space and time only trends and spatio-temporal interaction effect in the case reports submitted to the state health departments in the region. Various socio-economic, environmental and climatic covariates screened a priori in a bivariate procedure were added to a main-effects Bayesian model in progressive steps to evaluate important drivers of RMSF space-time patterns in the region. Our results show a steady increase in RMSF incidence over the study period to newer geographic areas, and the posterior probabilities of county-specific trends indicate clustering of high risk counties in the central and southern parts of the study region. At the spatial scale of a county, the prevalence levels of RMSF is influenced by poverty status, average relative humidity, and average land surface temperature (>35°C) in the region, and the relevance of these factors in the context of climate-change impacts on tick-borne diseases are discussed.

Nightlights along the Eastern Alpine river network in Austria and Italy as a proxy of human presence

NASA Astrophysics Data System (ADS)

Ceola, Serena; Montanari, Alberto; Parajka, Juraj; Viglione, Alberto; Bloeschl, Guenter

2016-04-01

Understanding the spatial and temporal distribution of human settlements and economic activities in relation to the geographical location of streams and rivers is of fundamental concern for several hydrologic issues such as flood risk and drought management, water pollution and exploitation, as well as stream ecological purposes. Indeed, the human presence close to streams and rivers is known to have consistently increased worldwide, therefore introducing dramatic anthropogenic and environmental changes. This research study analyses the spatial and temporal evolution of human settlements and associated economic activity, derived from nighttime lights, in the Eastern Alpine region. Nightlights, available at a 1 km spatial resolution and for a 22-year period, constitute an excellent data base, which allows to explore in details human signatures. In this experiment, nightlights are associated to five distinct distance-from-river classes, by using the CCM river network data base. From the temporal perspective, nightlights in correspondence of each distance-from-river class within each study region show an overall increasing trend, whereas the spatial trends differs among the study regions. More information about the analysis and project are available at: http://www.water-switch-on.eu/.

Triennial changes in groundwater quality in aquifers used for public supply in California: Utility as indicators of temporal trends

USGS Publications Warehouse

Kent, Robert; Landon, Matthew K.

2016-01-01

From 2004 to 2011, the U.S. Geological Survey collected samples from 1686 wells across the State of California as part of the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment (GAMA) Priority Basin Project (PBP). From 2007 to 2013, 224 of these wells were resampled to assess temporal trends in water quality. The samples were analyzed for 216 water-quality constituents, including inorganic and organic compounds as well as isotopic tracers. The resampled wells were grouped into five hydrogeologic zones. A nonparametric hypothesis test was used to test the differences between initial sampling and resampling results to evaluate possible step trends in water-quality, statewide, and within each hydrogeologic zone. The hypothesis tests were performed on the 79 constituents that were detected in more than 5 % of the samples collected during either sampling period in at least one hydrogeologic zone. Step trends were detected for 17 constituents. Increasing trends were detected for alkalinity, aluminum, beryllium, boron, lithium, orthophosphate, perchlorate, sodium, and specific conductance. Decreasing trends were detected for atrazine, cobalt, dissolved oxygen, lead, nickel, pH, simazine, and tritium. Tritium was expected to decrease due to decreasing values in precipitation, and the detection of decreases indicates that the method is capable of resolving temporal trends.

Elevation-dependent temperature trends in the Rocky Mountain Front Range: changes over a 56- and 20-year record.

PubMed

McGuire, Chris R; Nufio, César R; Bowers, M Deane; Guralnick, Robert P

2012-01-01

Determining the magnitude of climate change patterns across elevational gradients is essential for an improved understanding of broader climate change patterns and for predicting hydrologic and ecosystem changes. We present temperature trends from five long-term weather stations along a 2077-meter elevational transect in the Rocky Mountain Front Range of Colorado, USA. These trends were measured over two time periods: a full 56-year record (1953-2008) and a shorter 20-year (1989-2008) record representing a period of widely reported accelerating change. The rate of change of biological indicators, season length and accumulated growing-degree days, were also measured over the 56 and 20-year records. Finally, we compared how well interpolated Parameter-elevation Regression on Independent Slopes Model (PRISM) datasets match the quality controlled and weather data from each station. Our results show that warming signals were strongest at mid-elevations over both temporal scales. Over the 56-year record, most sites show warming occurring largely through increases in maximum temperatures, while the 20-year record documents warming associated with increases in maximum temperatures at lower elevations and increases in minimum temperatures at higher elevations. Recent decades have also shown a shift from warming during springtime to warming in July and November. Warming along the gradient has contributed to increases in growing-degree days, although to differing degrees, over both temporal scales. However, the length of the growing season has remained unchanged. Finally, the actual and the PRISM interpolated yearly rates rarely showed strong correlations and suggest different warming and cooling trends at most sites. Interpretation of climate trends and their seasonal biases in the Rocky Mountain Front Range are dependent on both elevation and the temporal scale of analysis. Given mismatches between interpolated data and the directly measured station data, we caution against an over-reliance on interpolation methods for documenting local patterns of climatic change.

Analysis of the spatial-temporal change of the vegetation index in the upper reach of Han River Basin in 2000-2016

NASA Astrophysics Data System (ADS)

Luan, Jinkai; Liu, Dengfeng; Zhang, Lianpeng; Huang, Qiang; Feng, Jiuliang; Lin, Mu; Li, Guobao

2018-06-01

Han River is the water source region of the middle route of South-to-North Water Diversion in China and the ecological projects were implemented since many years ago. In order to monitor the change of vegetation in Han River and evaluate the effect of ecological projects, it is needed to reveal the spatial-temporal change of the vegetation in the upper reach of Han River quantitatively. The study is based on MODIS/Terra NDVI remote sensing data, and analyzes the spatial-temporal changes of the NDVI in August from 2000 to 2016 at pixel scale in the upper reach of Han River Basin. The results show that, the area with increasing NDVI between 0 and 0.005 per year accounts for 62.07 % of the area of upper reach of Han River Basin, and the area with changing rate between -0.005 and 0 per year accounts for 26.65 % of the research area. The area with significant decreasing trend only accounts for 2.76 %, while area significant increasing trend accounts for 13.47 %, and the area with increasing NDVI is much larger than the area with reducing NDVI. The vegetation index of each county is evaluated and found that, the areal proportion with significant decreasing trend in Hantai is the biggest, reaching 35.57 %. The areal proportion with significant increasing trend in Zhenba County, Ziyang County, Xunyang County, Zhashui County, Shangzhou District, Shanyang County and Yun County is larger than the others, and the areal proportions are more than 20 %. The largest areal proportion with significant increasing trend is in Shangzhou District and it reaches 31.11 %. On the whole, the area ratio in all districts and counties with increasing NDVI is much larger than the area ratio with decreasing NDVI.

Elevation-Dependent Temperature Trends in the Rocky Mountain Front Range: Changes over a 56- and 20-Year Record

PubMed Central

McGuire, Chris R.; Nufio, César R.; Bowers, M. Deane; Guralnick, Robert P.

2012-01-01

Determining the magnitude of climate change patterns across elevational gradients is essential for an improved understanding of broader climate change patterns and for predicting hydrologic and ecosystem changes. We present temperature trends from five long-term weather stations along a 2077-meter elevational transect in the Rocky Mountain Front Range of Colorado, USA. These trends were measured over two time periods: a full 56-year record (1953–2008) and a shorter 20-year (1989–2008) record representing a period of widely reported accelerating change. The rate of change of biological indicators, season length and accumulated growing-degree days, were also measured over the 56 and 20-year records. Finally, we compared how well interpolated Parameter-elevation Regression on Independent Slopes Model (PRISM) datasets match the quality controlled and weather data from each station. Our results show that warming signals were strongest at mid-elevations over both temporal scales. Over the 56-year record, most sites show warming occurring largely through increases in maximum temperatures, while the 20-year record documents warming associated with increases in maximum temperatures at lower elevations and increases in minimum temperatures at higher elevations. Recent decades have also shown a shift from warming during springtime to warming in July and November. Warming along the gradient has contributed to increases in growing-degree days, although to differing degrees, over both temporal scales. However, the length of the growing season has remained unchanged. Finally, the actual and the PRISM interpolated yearly rates rarely showed strong correlations and suggest different warming and cooling trends at most sites. Interpretation of climate trends and their seasonal biases in the Rocky Mountain Front Range are dependent on both elevation and the temporal scale of analysis. Given mismatches between interpolated data and the directly measured station data, we caution against an over-reliance on interpolation methods for documenting local patterns of climatic change. PMID:22970205

Statistical trend analysis of groundwater data at Louisiana Army Ammunition Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhinge, D; Patel, J.; Skibinski, J.N.

1994-12-31

Statistical regression techniques were used to characterize temporal trends in groundwater monitoring data collected between 1980 and 1994 at Former Area P Lagoons, Louisiana Army Ammunition Plant (LAAP), a National Priorities List (NPL) site. Groundwater sampling data were evaluated for 12 wells (9 in the shallow aquifer and 3 in the deeper aquifer) and 9 contaminants of concern (COCs). A trend index (TI) was calculated from the sum of the number of improving and stable trends minus the number of deteriorating trends for each contaminant, each well, and the overall site. A positive TI indicates an improving trend for themore » site, contaminant, or well. Conversely, a negative TI indicates a deteriorating trend. The overall trend indices at the site for the shallow and deeper aquifers were found to be positive, indicating that the groundwater quality at Area P is generally improving. Interim remedial action was conducted at Area P from 1988 through 1990. The effect of remedial activities on groundwater quality was assessed by comparing the groundwater concentrations of nitro compounds measured immediately after the site remediation to those measured prior to the remedial action. The regression curves and the data indicated that a downward trend in the groundwater concentrations was observed immediately following the remediation activity at Area P. The trends from the regression analysis indicated that the overall remedy at Area P has been effective in reducing COC concentrations in groundwater.« less

Tracking Equilibrium and Nonequilibrium Shifts in Data with TREND.

PubMed

Xu, Jia; Van Doren, Steven R

2017-01-24

Principal component analysis (PCA) discovers patterns in multivariate data that include spectra, microscopy, and other biophysical measurements. Direct application of PCA to crowded spectra, images, and movies (without selecting peaks or features) was shown recently to identify their equilibrium or temporal changes. To enable the community to utilize these capabilities with a wide range of measurements, we have developed multiplatform software named TREND to Track Equilibrium and Nonequilibrium population shifts among two-dimensional Data frames. TREND can also carry this out by independent component analysis. We highlight a few examples of finding concurrent processes. TREND extracts dual phases of binding to two sites directly from the NMR spectra of the titrations. In a cardiac movie from magnetic resonance imaging, TREND resolves principal components (PCs) representing breathing and the cardiac cycle. TREND can also reconstruct the series of measurements from selected PCs, as illustrated for a biphasic, NMR-detected titration and the cardiac MRI movie. Fidelity of reconstruction of series of NMR spectra or images requires more PCs than needed to plot the largest population shifts. TREND reads spectra from many spectroscopies in the most common formats (JCAMP-DX and NMR) and multiple movie formats. The TREND package thus provides convenient tools to resolve the processes recorded by diverse biophysical methods. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Utilizing Higher Resolution Land Surface Remote Sensing Data for Assessing Recent Trends over Asia Monsoon Region

NASA Technical Reports Server (NTRS)

Shen, Suhung; Leptoukh, Gregory

2010-01-01

The slide presentation discusses the integration of 1-kilometer spatial resolution land temperature data from the Moderate Resolution Imaging Spectroradiometer (MODIS), with 8-day temporal resolution, into the NASA Monsoon-Asia Integrated Regional Study (MAIRS) Data Center. The data will be available for analysis and visualization in the Giovanni data system. It discusses the NASA MAIRS Data Center, presents an introduction to the data access tools, and an introduction of Products available from the service, discusses the higher resolution Land Surface Temperature (LST) and presents preliminary results of LST Trends over China.

Contrasted spatial and long-term trends in precipitation chemistry and deposition fluxes at rural stations in France

NASA Astrophysics Data System (ADS)

Pascaud, A.; Sauvage, S.; Coddeville, P.; Nicolas, M.; Croisé, L.; Mezdour, A.; Probst, A.

2016-12-01

The long-distance effect of atmospheric pollution on ecosystems has led to the conclusion of international agreements to regulate atmospheric emissions and monitor their impact. This study investigated variations in atmospheric deposition chemistry in France using data gathered from three different monitoring networks (37 stations) over the period from 1995 to 2007. Despite some methodological differences (e.g. type of collector, frequency of sampling and analysis), converging results were found in spatial variations, seasonal patterns and temporal trends. With regard to spatial variations, the mean annual pH in particular ranged from 4.9 in the north-east to 5.8 in the south-east. This gradient was related to the concentration of NO3- and non-sea-salt SO42- (maximum volume-weighted mean of 38 and 31 μeq l-1 respectively) and of acid-neutralising compounds such as non-sea-salt Ca2+ and NH4+. In terms of seasonal variations, winter and autumn pH were linked to lower acidity neutralisation than during the warm season. The temporal trends in atmospheric deposition varied depending on the chemical species and site location. The most significant and widespread trend was the decrease in non-sea-salt SO42- concentrations (significant at 65% of the stations). At the same time, many stations showed an increasing trend in annual pH (+0.3 on average for 16 stations). These two trends are probably due to the reduction in SO2 emissions that has been imposed in Europe since the 1980s. Temporal trends in inorganic N concentrations were rather moderate and not consistent with the trends reported in emission estimates. Despite the reduction in NOx emissions, NO3- concentrations in atmospheric deposition remained mostly unchanged or even increased at three stations (+0.43 μeq l-1 yr-1 on average). In contrast NH4+ concentrations in atmospheric deposition decreased at several stations located in western and northern areas, while the estimates of NH3 emissions remained fairly stable. The decrease in non-sea-salt SO42- and NH4+ concentrations was mainly due to a decrease in summer values and can in part be related to a dilution process since the precipitation amount showed an increasing trend during the summer. Furthermore, increasing trends in NO3- concentrations in the spring and, to a lesser extent, in NH4+ concentrations suggested that other atmospheric physicochemical processes should also be taken into account.

Spatio-temporal variability and trends of precipitation and extreme rainfall events in Ethiopia in 1980-2010

NASA Astrophysics Data System (ADS)

Gummadi, Sridhar; Rao, K. P. C.; Seid, Jemal; Legesse, Gizachew; Kadiyala, M. D. M.; Takele, Robel; Amede, Tilahun; Whitbread, Anthony

2017-12-01

This article summarizes the results from an analysis conducted to investigate the spatio-temporal variability and trends in the rainfall over Ethiopia over a period of 31 years from 1980 to 2010. The data is mostly observed station data supplemented by bias-corrected AgMERRA climate data. Changes in annual and Belg (March-May) and Kiremt (June to September) season rainfalls and rainy days have been analysed over the entire Ethiopia. Rainfall is characterized by high temporal variability with coefficient of variation (CV, %) varying from 9 to 30% in the annual, 9 to 69% during the Kiremt season and 15-55% during the Belg season rainfall amounts. Rainfall variability increased disproportionately as the amount of rainfall declined from 700 to 100 mm or less. No significant trend was observed in the annual rainfall amounts over the country, but increasing and decreasing trends were observed in the seasonal rainfall amounts in some areas. A declining trend is also observed in the number of rainy days especially in Oromia, Benishangul-Gumuz and Gambella regions. Trends in seasonal rainfall indicated a general decline in the Belg season and an increase in the Kiremt season rainfall amounts. The increase in rainfall during the main Kiremt season along with the decrease in the number of rainy days leads to an increase in extreme rainfall events over Ethiopia. The trends in the 95th-percentile rainfall events illustrate that the annual extreme rainfall events are increasing over the eastern and south-western parts of Ethiopia covering Oromia and Benishangul-Gumuz regions. During the Belg season, extreme rainfall events are mostly observed over central Ethiopia extending towards the southern part of the country while during the Kiremt season, they are observed over parts of Oromia, (covering Borena, Guji, Bali, west Harerge and east Harerge), Somali, Gambella, southern Tigray and Afar regions. Changes in the intensity of extreme rainfall events are mostly observed over south-eastern parts of Ethiopia extending to the south-west covering Somali and Oromia regions. Similar trends are also observed in the greatest 3-, 5- and 10-day rainfall amounts. Changes in the consecutive dry and wet days showed that consecutive wet days during Belg and Kiremt seasons decreased significantly in many areas in Ethiopia while consecutive dry days increased. The consistency in the trends over large spatial areas confirms the robustness of the trends and serves as a basis for understanding the projected changes in the climate. These results were discussed in relation to their significance to agriculture.

Average sperm count remains unchanged despite reduction in maternal smoking: results from a large cross-sectional study with annual investigations over 21 years.

PubMed

Priskorn, L; Nordkap, L; Bang, A K; Krause, M; Holmboe, S A; Egeberg Palme, D L; Winge, S B; Mørup, N; Carlsen, E; Joensen, U N; Blomberg Jensen, M; Main, K M; Juul, A; Skakkebaek, N E; Jensen, T K; Jørgensen, N

2018-06-01

How are temporal trends in lifestyle factors, including exposure to maternal smoking in utero, associated to semen quality in young men from the general population? Exposure to maternal smoking was associated with lower sperm counts but no overall increase in sperm counts was observed during the study period despite a decrease in this exposure. Meta-analyses suggest a continuous decline in semen quality but few studies have investigated temporal trends in unselected populations recruited and analysed with the same protocol over a long period and none have studied simultaneous trends in lifestyle factors. Cross-sectional population-based study including ~300 participants per year (total number = 6386) between 1996 and 2016. The study is based on men from the Greater Copenhagen area, Denmark, with a median age of 19 years, and unselected with regard to fertility status and semen quality. The men delivered a semen sample, had a blood sample drawn and a physical examination performed and answered a comprehensive questionnaire, including information on lifestyle and the mother's pregnancy. Temporal trends in semen quality and lifestyle were illustrated graphically, and trends in semen parameters and the impact of prenatal and current lifestyle factors were explored in multiple regression analyses. Throughout the study period, 35% of the men had low semen quality. Overall, there were no persistent temporal trends in semen quality, testicular volume or levels of follicle-stimulating hormone over the 21 years studied. The men's alcohol intake was lowest between 2011 and 2016, whereas BMI, use of medication and smoking showed no clear temporal trends. Parental age increased, and exposure in utero to maternal smoking declined from 40% among men investigated in 1996-2000 to 18% among men investigated in 2011-2016. Exposure to maternal smoking was associated with lower sperm counts but no overall increase in sperm counts was observed despite the decrease in this exposure. Information of current and prenatal lifestyle was obtained by self-report, and the men delivered only one semen sample each. The significant decline in in utero exposure to maternal smoking, which was not reflected in an overall improvement of semen quality at the population level, suggest that other unknown adverse factors may maintain the low semen quality among Danish men. The study has received financial support from the ReproUnion; the Research fund of Rigshospitalet, Copenhagen University Hospital; the European Union (Contract numbers BMH4-CT96-0314,QLK4-CT-1999-01422, QLK4-CT-2002-00603, FP7/2007-2013, DEER Grant agreement no. 212844); the Danish Ministry of Health; the Danish Environmental Protection Agency; A.P. Møller and wife Chastine McKinney Møllers foundation; and Svend Andersens Foundation. None of the funders had any role in the study design, collection, analysis or interpretation of data, writing of the paper or publication decisions. N/A.

Trends in incidence of primary brain cancer in New Zealand, 1995 to 2010.

PubMed

Kim, Stella J-H; Ioannides, Sally J; Elwood, J Mark

2015-04-01

Case-control studies have linked mobile phone use to an increased risk of glioma in the most exposed brain areas, the temporal and parietal lobes, although inconsistently. We examined time trends in the incidence rates of brain malignancies in New Zealand from 1995 to 2010. Data from the New Zealand Cancer Registry was used to calculate incidence rates of primary brain cancer, by age, gender, morphology and anatomical site. Log-linear regression analysis was used to assess trends in the annual incidence of primary brain cancer; annual percentage changes and their 95% confidence intervals were estimated. No consistent increases in all primary brain cancer, glioma, or temporal or parietal lobe glioma were seen. At ages 10-69, the incidence of all brain cancers declined significantly. Incidence of glioma increased at ages over 70. In New Zealand, there has been no consistent increase in incidence rates of primary brain cancers. An increase in glioma at ages over 70 is likely to be due to improvements in diagnosis. As with any such studies, a small effect, or one with a latent period of more than 10 to 15 years, cannot be excluded. © 2015 Public Health Association of Australia.

Historical Records and Source Apportionment of Polycyclic Aromatic Hydrocarbons Over the Past 100 Years in Dianchi Lake, a Plateau Lake in Southwest China.

PubMed

Ma, Xiaohua; Han, Xiuxiu; Jiang, Quanliang; Huang, Changchun; Huang, Tao; Yang, Hao; Yao, Ling

2018-04-12

Two sediment cores were collected from Dianchi Lake, a plateau lake in Southwest China, to study the temporal trends and to investigate the sources of sedimentary deposited polycyclic aromatic hydrocarbon. The ΣPAH16 concentration in the two sediment cores ranged from 172.5 to 2244.8 ng/g and from 211.4 to 1777.8 ng/g, with mean values of 1106.2 and 865.1 ng/g, respectively. Three temporal trends for the ΣPAH16 concentration and the composition of PAHs in Dianchi Lake all showed three typical changing stages: (1) slight changes in deeper segments before the 1950s; (2) a rapid increase in PAH concentrations between the 1960s and 1990s; and (3) a slight reduction from the 1990s onward. These trends differ from those observed in developed countries due to differences in the timing of industrialization and urbanization processes. According to the results of the molecular ratios and principal component analysis, the PAH deposition was dominated by coal combustion, wood combustion, and vehicle emissions before and after the 1960s, respectively.

Spatial pattern and temporal trend of mortality due to tuberculosis 10

PubMed Central

de Queiroz, Ana Angélica Rêgo; Berra, Thaís Zamboni; Garcia, Maria Concebida da Cunha; Popolin, Marcela Paschoal; Belchior, Aylana de Souza; Yamamura, Mellina; dos Santos, Danielle Talita; Arroyo, Luiz Henrique; Arcêncio, Ricardo Alexandre

2018-01-01

ABSTRACT Objectives: To describe the epidemiological profile of mortality due to tuberculosis (TB), to analyze the spatial pattern of these deaths and to investigate the temporal trend in mortality due to tuberculosis in Northeast Brazil. Methods: An ecological study based on secondary mortality data. Deaths due to TB were included in the study. Descriptive statistics were calculated and gross mortality rates were estimated and smoothed by the Local Empirical Bayesian Method. Prais-Winsten’s regression was used to analyze the temporal trend in the TB mortality coefficients. The Kernel density technique was used to analyze the spatial distribution of TB mortality. Results: Tuberculosis was implicated in 236 deaths. The burden of tuberculosis deaths was higher amongst males, single people and people of mixed ethnicity, and the mean age at death was 51 years. TB deaths were clustered in the East, West and North health districts, and the tuberculosis mortality coefficient remained stable throughout the study period. Conclusions: Analyses of the spatial pattern and temporal trend in mortality revealed that certain areas have higher TB mortality rates, and should therefore be prioritized in public health interventions targeting the disease. PMID:29742272

Spatiotemporal analysis of the agricultural drought risk in Heilongjiang Province, China

NASA Astrophysics Data System (ADS)

Pei, Wei; Fu, Qiang; Liu, Dong; Li, Tian-xiao; Cheng, Kun; Cui, Song

2017-06-01

Droughts are natural disasters that pose significant threats to agricultural production as well as living conditions, and a spatial-temporal difference analysis of agricultural drought risk can help determine the spatial distribution and temporal variation of the drought risk within a region. Moreover, this type of analysis can provide a theoretical basis for the identification, prevention, and mitigation of drought disasters. In this study, the overall dispersion and local aggregation of projection points were based on research by Friedman and Tukey (IEEE Trans on Computer 23:881-890, 1974). In this work, high-dimensional samples were clustered by cluster analysis. The clustering results were represented by the clustering matrix, which determined the local density in the projection index. This method avoids the problem of determining a cutoff radius. An improved projection pursuit model is proposed that combines cluster analysis and the projection pursuit model, which offer advantages for classification and assessment, respectively. The improved model was applied to analyze the agricultural drought risk of 13 cities in Heilongjiang Province over 6 years (2004, 2006, 2008, 2010, 2012, and 2014). The risk of an agricultural drought disaster was characterized by 14 indicators and the following four aspects: hazard, exposure, sensitivity, and resistance capacity. The spatial distribution and temporal variation characteristics of the agricultural drought risk in Heilongjiang Province were analyzed. The spatial distribution results indicated that Suihua, Qigihar, Daqing, Harbin, and Jiamusi are located in high-risk areas, Daxing'anling and Yichun are located in low-risk areas, and the differences among the regions were primarily caused by the aspects exposure and resistance capacity. The temporal variation results indicated that the risk of agricultural drought in most areas presented an initially increasing and then decreasing trend. A higher value for the exposure aspect increased the risk of drought, whereas a higher value for the resistance capacity aspect reduced the risk of drought. Over the long term, the exposure level of the region presented limited increases, whereas the resistance capacity presented considerable increases. Therefore, the risk of agricultural drought in Heilongjiang Province will continue to exhibit a decreasing trend.

Spatial-temporal Evolution of Vegetation Coverage and Analysis of it’s Future Trends in Wujiang River Basin

NASA Astrophysics Data System (ADS)

Xiao, Jianyong; Bai, Xiaoyong; Zhou, Dequan; Qian, Qinghuan; Zeng, Cheng; Chen, Fei

2018-01-01

Vegetation coverage dynamics is affected by climatic, topography and human activities, which is an important indicator reflecting the regional ecological environment. Revealing the spatial-temporal characteristics of vegetation coverage is of great significance to the protection and management of ecological environment. Based on MODIS NDVI data and the Maximum Value Composites (MVC), we excluded soil spectrum interference to calculate Fractional Vegetation Coverage (FVC). Then the long-term FVC was used to calculate the spatial pattern and temporal variation of vegetation in Wujiang River Basin from 2000 to 2016 by using Trend analysis and Hurst index. The relationship between topography and spatial distribution of FVC was analyzed. The main conclusions are as follows: (1) The multi-annual mean vegetation coverage reveals a spatial distribution variation characteristic of low value in midstream and high level in other parts of the basin, owing a mean value of 0.6567. (2) From 2000 to 2016, the FVC of the Wujiang River Basin fluctuated between 0.6110 and 0.7380, and the overall growth rate of FVC was 0.0074/a. (3) The area of vegetation coverage tending to improve is more than that going to degrade in the future. Grass land, Arable land and Others improved significantly; karst rocky desertification comprehensive management project lead to persistent vegetation coverage improvement of Grass land, Arable land and Others. Residential land is covered with obviously degraded vegetation, resulting of urban sprawl; (4) The spatial distribution of FVC is positively correlated with TNI. Researches of spatial-temporal evolution of vegetation coverage have significant meaning for the ecological environment protection and management of the Wujiang River Basin.

SNR and functional sensitivity of BOLD and perfusion-based fMRI using arterial spin labeling with spiral SENSE at 3 T.

PubMed

Perthen, Joanna E; Bydder, Mark; Restom, Khaled; Liu, Thomas T

2008-05-01

Blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) studies using parallel imaging to reduce the readout window have reported a loss in temporal signal-to-noise ratio (SNR) that is less than would be expected given a purely thermal noise model. In this study, the impact of parallel imaging on the noise components and functional sensitivity of both BOLD and perfusion-based fMRI data was investigated. Dual-echo arterial spin labeling data were acquired on five subjects using sensitivity encoding (SENSE), at reduction factors (R) of 1, 2 and 3. Direct recording of cardiac and respiratory activity during data acquisition enabled the retrospective removal of physiological noise. The temporal SNR of the perfusion time series closely followed the thermal noise prediction of a radicalR loss in SNR as the readout window was shortened, with temporal SNR values (relative to the R=1 data) of 0.72 and 0.56 for the R=2 and R=3 data, respectively, after accounting for physiological noise. However, the BOLD temporal SNR decreased more slowly than predicted even after accounting for physiological noise, with relative temporal SNR values of 0.80 and 0.63 for the R=2 and R=3 data, respectively. Spectral analysis revealed that the BOLD trends were dominated by low-frequency fluctuations, which were not dominant in the perfusion data due to signal processing differences. The functional sensitivity, assessed using mean F values over activated regions of interest (ROIs), followed the temporal SNR trends for the BOLD data. However, results for the perfusion data were more dependent on the threshold used for ROI selection, most likely due to the inherently low SNR of functional perfusion data.

Earth Observation for monitoring phenology for european land use and ecosystems over 1998-2011

NASA Astrophysics Data System (ADS)

Ceccherini, Guido; Gobron, Nadine

2013-04-01

Long-term measurements of plant phenology have been used to track vegetation responses to climate change but are often limited to particular species and locations and may not represent synoptic patterns. Given the limitations of working directly with in-situ data, many researchers have instead used available satellite remote sensing. Remote sensing extends the possible spatial coverage and temporal range of phenological assessments of environmental change due to the greater availability of observations. Variations and trends of vegetation dynamics are important because they alter the surface carbon, water and energy balance. For example, the net ecosystem CO2 exchange of vegetation is strongly linked to length of the growing season: extentions and decreases in length of growing season modify carbon uptake and the amount of CO2 in the atmosphere. Advances and delays in starting of growing season also affect the surface energy balance and consequently transpiration. The Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) is a key climate variable identified by Global Terrestrial Observing System (GTOS) that can be monitored from space. This dimensionless variable - varying between 0 and 1- is directly linked to the photosynthetic activity of vegetation, and therefore, can monitor changes in phenology. In this study, we identify the spatio/temporal patterns of vegetation dynamics using a long-term remotely sensed FAPAR dataset over Europe. Our aim is to provide a quantitative analysis of vegetation dynamics relevant to climate studies in Europe. As part of this analysis, six vegetation phenological metrics have been defined and made routinely in Europe. Over time, such metrics can track simple, yet critical, impacts of climate change on ecosystems. Validation has been performed through a direct comparison against ground-based data over ecological sites. Subsequently, using the spatio/temporal variability of this suite of metrics, we classify areas with similar vegetation dynamics. This permits assessment of variations and trends of vegetation dynamics over Europe. Statistical tests to assess the significance of temporal changes are used to evaluate trends in the metrics derived from the recorded time series of the FAPAR.

Temporal patterns of vegetation phenology and their responses to climate change in mid-latitude grasslands of the Northern Hemisphere

NASA Astrophysics Data System (ADS)

Ren, S.; Chen, X.; Qin, Q.; Zhang, Y.; Wu, Z.

2017-12-01

Grassland ecosystem is greatly sensitive to regional and global climate changes. In this study, the start (SOS) and end (EOS) date of growing season were extracted from NDVI data (1981 2014) across the mid-latitude (30°N 55°N) grasslands of Northern Hemisphere. We first validated their accuracy by ground observed phenological data and phenological metrics derived from gross primary production (GPP) data. And then, main climatic factors influencing the temporal patterns of SOS/EOS were explored by means of gridded meteorological data and partial correlation analysis. Based on the results of above statistical analysis, the similarities and differences of spring and autumn phenological responses to climate change among North American grasslands, Mid-West Asian grasslands, and Mongolian grasslands were analyzed. The main results and conclusions are as follows. First, a significant positive correlation was found between SOS/EOS and observed green-up/brown-off date (P<0.05) and GPP-based SOS/EOS (P<0.05), which means remote sensed SOS/EOS can reflect temporal dynamics of terrestrial vegetation phenology. Second, SOS in Mid-West Asian grasslands showed a significant advancing trend (0.22 days/year, P<0.01), whereas the trend of SOS in North American grasslands and Mongolian grasslands was not significant. EOS in North American grasslands (0.31 dyas/year, P<0.01) and Mongolian grasslands (0.09 days/year, P<0.05) both presented a significant delaying trend, but the trend of EOS in Mid-West Asian grasslands was not significant. Furthermore, the correlation analysis of SOS/EOS inter-annual fluctuations and hydrothermal factors showed that a significant negative correlation was found between SOS and the pre-season temperature in 41.6% of pixels (P<0.05), while a significant negative/positive correlation was detected between SOS and pre-season rainfall/snowfall in 14.6%/19.0% of pixels (P<0.05). EOS was significantly positively correlated with pre-season rainfall in 34.5% of pixels (P<0.05), and significantly negatively/positively correlated with pre-season temperature in 12.1%/11.9% of pixels (P<0.05). This indicates that the fluctuations of SOS and EOS are mainly affected by pre-season temperature and pre-season rainfall.

The impacts of emission trends of POPs on human concentration dynamics: Lessons learned from a longitudinal study in Norway (1979-2007).

PubMed

Nøst, Therese Haugdahl; Sandanger, Torkjel Manning; Nieboer, Evert; Odland, Jon Øyvind; Breivik, Knut

2017-06-01

In this short communication, our focus is on the relationship between human concentrations of select persistent organic pollutants (POPs) and environmental emissions. It is based on a longitudinal study (1979-2007) conducted in Norway. Our aim was to extract general insights from observed and predicted temporal trends in human concentrations of 49 POPs to assist in the design and interpretation of future monitoring studies. Despite considerable decline for polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) since 1986, the sum of the targeted POPs increased from 1979 until 2001, with per- and polyfluorinated alkyl substances (PFASs) dominating recent blood burden measurements. Specifically, the time trends in serum concentrations of POPs, exemplified by PCB-153, 1,1'-(2,2,2-Trichloroethane-1,1-diyl)bis(4-chlorobenzene) (DDT) and perfluorooctane sulfonic acid (PFOS), resembled the trends in available data on their emissions, production or use. These observations suggest that interpretations of human biomonitoring data on persistent compounds must consider historic emissions, which likely vary spatially across the globe. Based on the different temporal trends observed across POP groups, it is evident that generalizations regarding temporal aspects have limitations. The discussion herein underscores the importance of understanding temporal variations in environmental emissions when designing and interpreting human biomonitoring studies. Copyright © 2017 Elsevier GmbH. All rights reserved.

Marked socioeconomic inequalities in hip fracture incidence rates during the Bone and Joint Decade (2000-2010) in Portugal: age and sex temporal trends in a population based study.

PubMed

Oliveira, Carla Maria; Alves, Sandra Maria; Pina, Maria Fátima

2016-08-01

Socioeconomic factors may influence changes in hip fracture (HF) incidence over time. We analysed HF temporal trends during the Bone and Joint Decade in Portugal (BJD-Portugal), 2000-2010, by regional socioeconomic status (SES), sex and age. We selected registers of patients aged 50+ years with HF (International Classification of Diseases, V.9-Clinical Modification, ICD9-CM) caused by traumas of low/moderate energy, from the National Hospital Discharge Database. Annual time series of age-specific incidence rates were calculated by sex and regional SES (deprived, medium, affluent). Generalised additive models were fitted to identify shape/turning points in temporal trends. We selected 96 905 HF (77.3% in women). Women were older than men at admission (81.2±8.5 vs 78.2±10.1 years-old, p<0.001). For women 65-79 years, a continuously decreasing trend (1.7%/year) only in affluent and increasing trends (3.3-3.4%/year) after 2006/2007 in medium and deprived was observed. For men, trends were stable or increased in almost all age/SES groups (only two decreasing periods). For the oldest women, all SES present similar trends: turning points around 2003 (initiating decreasing periods: 1.8-2.9%/year) and around 2007 (initiating increasing periods: 3.7-3.3%/year). There were SES-sex-age inequalities in temporal trends during BJD-Portugal: marked SES inequalities among women aged 65-79 years (a persistent, decreasing trend only in the affluent) vanished among the oldest women; the same was not observed in men, for them, there were almost no declining periods; women aged ≥80 years, presented increasing trends around 2007, as in most deprived/age/sex groups. Despite some successful periods of decreasing trends, incidence rates did not improve overall in almost all age groups and both sexes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Evaluation of a regional monitoring program's statistical power to detect temporal trends in forest health indicators

USGS Publications Warehouse

Perles, Stephanie J.; Wagner, Tyler; Irwin, Brian J.; Manning, Douglas R.; Callahan, Kristina K.; Marshall, Matthew R.

2014-01-01

Forests are socioeconomically and ecologically important ecosystems that are exposed to a variety of natural and anthropogenic stressors. As such, monitoring forest condition and detecting temporal changes therein remain critical to sound public and private forestland management. The National Parks Service’s Vital Signs monitoring program collects information on many forest health indicators, including species richness, cover by exotics, browse pressure, and forest regeneration. We applied a mixed-model approach to partition variability in data for 30 forest health indicators collected from several national parks in the eastern United States. We then used the estimated variance components in a simulation model to evaluate trend detection capabilities for each indicator. We investigated the extent to which the following factors affected ability to detect trends: (a) sample design: using simple panel versus connected panel design, (b) effect size: increasing trend magnitude, (c) sample size: varying the number of plots sampled each year, and (d) stratified sampling: post-stratifying plots into vegetation domains. Statistical power varied among indicators; however, indicators that measured the proportion of a total yielded higher power when compared to indicators that measured absolute or average values. In addition, the total variability for an indicator appeared to influence power to detect temporal trends more than how total variance was partitioned among spatial and temporal sources. Based on these analyses and the monitoring objectives of theVital Signs program, the current sampling design is likely overly intensive for detecting a 5 % trend·year−1 for all indicators and is appropriate for detecting a 1 % trend·year−1 in most indicators.

Exploring Temporal Frameworks for Constructing Longitudinal Instance-Specific Models from Clinical Data

ERIC Educational Resources Information Center

Watt, Emily

2012-01-01

The prevalence of the EMR in biomedical research is growing, the EMR being regarded as a source of contextually rich, longitudinal data for computation and statistical/trend analysis. However, models trained with data abstracted from the EMR often (1) do not capture all features needed to accurately predict the patient's future state and to…

Analysis on variability and trend in Antarctic sea ice albedo between 1983 and 2009

NASA Astrophysics Data System (ADS)

Seo, Minji; Kim, Hyun-cheol; Choi, Sungwon; Lee, Kyeong-sang; Han, Kyung-soo

2017-04-01

Sea ice is key parameter in order to understand the cryosphere climate change. Several studies indicate the different trend of sea ice between Antarctica and Arctic. Albedo is important factor for understanding the energy budget and factors for observing of environment changes of Cryosphere such as South Pole, due to it mainly covered by ice and snow with high albedo value. In this study, we analyzed variability and trend of long-term sea ice albedo data to understand the changes of sea ice over Antarctica. In addiction, sea ice albedo researched the relationship with Antarctic oscillation in order to determine the atmospheric influence. We used the sea ice albedo data at The Satellite Application Facility on Climate Monitoring and Antarctic Oscillation data at NOAA Climate Prediction Center (CPC). We analyzed the annual trend in albedo using linear regression to understand the spatial and temporal tendency. Antarctic sea ice albedo has two spatial trend. Weddle sea / Ross sea sections represent a positive trend (0.26% ˜ 0.04% yr-1) and Bellingshausen Amundsen sea represents a negative trend (- 0.14 ˜ -0.25%yr-1). Moreover, we performed the correlation analysis between albedo and Antarctic oscillation. As a results, negative area indicate correlation coefficient of - 0.3639 and positive area indicates correlation coefficient of - 0.0741. Theses results sea ice albedo has regional trend according to ocean. Decreasing sea ice trend has negative relationship with Antarctic oscillation, its represent a possibility that sea ice influence atmospheric factor.

Assessing the burden of intestinal parasites affecting newly arrived immigrants in Qatar.

PubMed

Abu-Madi, Marawan A; Behnke, Jerzy M; Ismail, Ahmed; Boughattas, Sonia

2016-12-01

In the last decades, the enormous influx of immigrants to industrialized countries has led to outbreaks of parasitic diseases, with enteric infections being amongst the most frequently encountered. In its strategy to control such infection, Qatar has established the Pre-Employment Certificate (PEC) program which requires medical inspection before arrival in Qatar and which is mandatory for immigrant workers travelling to the country. To assess the reliability of the PEC, we conducted a survey of intestinal parasites, based on examination of stool samples provided by immigrant workers (n = 2,486) recently arrived in Qatar. Overall prevalence of helminths was 7.0% and that of protozoa was 11.7%. Prevalence of combined helminths was highest among the western Asians and the highest prevalence of combined protozoan parasites was among workers from North to Saharan Africa. Analysis of temporal changes showed an increasing trend of protozoan infections over the investigated 3 years. A major contribution to this temporal change in prevalence came from Blastocystis hominis as well as from other protozoan species: Giardia duodenalis and Endolimax nana. Analysis of the temporal trend in species richness of the protozoan species showed a significant increase in the mean number of species harboured per subject across this period. The increase of protozoan infections over recent years raises some concerns. It suggests that screening protocols for applicants for visas/work permits needs to be revised giving more careful attention to the intestinal protozoan infections that potential immigrants may harbor.

Regional trend analysis of surface ozone observations from monitoring networks in eastern North America, Europe and East Asia

NASA Astrophysics Data System (ADS)

Chang, K. L.; Petropavlovskikh, I. V.; Cooper, O. R.; Schultz, M.; Wang, T.

2017-12-01

Surface ozone is a greenhouse gas and pollutant detrimental to human health and crop and ecosystem productivity. The Tropospheric Ozone Assessment Report (TOAR) is designed to provide the research community with an up-to-date observation-based overview of tropospheric ozone's global distribution and trends. The TOAR Surface Ozone Database contains ozone metrics at thousands of monitoring sites around the world, densely clustered across mid-latitude North America, western Europe and East Asia. Calculating regional ozone trends across these locations is challenging due to the uneven spacing of the monitoring sites across urban and rural areas. To meet this challenge we conducted a spatial and temporal trend analysis of several TOAR ozone metrics across these three regions for summertime (April-September) 2000-2014, using the generalized additive mixed model (GAMM). Our analysis indicates that East Asia has the greatest human and plant exposure to ozone pollution among investigating regions, with increasing ozone levels through 2014. The results also show that ozone mixing ratios continue to decline significantly over eastern North America and Europe, however, there is less evidence for decreases of daytime average ozone at urban sites. The present-day spatial coverage of ozone monitors in East Asia (South Korea and Japan) and eastern North America is adequate for estimating regional trends by simply taking the average of the individual trends at each site. However the European network is more sparsely populated across its northern and eastern regions and therefore a simple average of the individual trends at each site does not yield an accurate regional trend. This analysis demonstrates that the GAMM technique can be used to assess the regional representativeness of existing monitoring networks, indicating those networks for which a regional trend can be obtained by simply averaging the trends of all individual sites and those networks that require a more sophisticated statistical approach.

Temporal trends in 137Cs concentrations in the bark, sapwood, heartwood, and whole wood of four tree species in Japanese forests from 2011 to 2016.

PubMed

Ohashi, Shinta; Kuroda, Katsushi; Takano, Tsutomu; Suzuki, Youki; Fujiwara, Takeshi; Abe, Hisashi; Kagawa, Akira; Sugiyama, Masaki; Kubojima, Yoshitaka; Zhang, Chunhua; Yamamoto, Koichi

2017-11-01

To understand the changes in radiocesium ( 137 Cs) concentrations in stem woods after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, we investigated 137 Cs concentrations in the bark, sapwood, heartwood, and whole wood of four major tree species at multiple sites with different levels of radiocesium deposition from the FDNPP accident since 2011 (since 2012 at some sites): Japanese cedar at four sites, hinoki cypress and Japanese konara oak at two sites, and Japanese red pine at one site. Our previous report on 137 Cs concentrations in bark and whole wood samples collected from 2011 to 2015 suggested that temporal variations were different among sites even within the same species. In the present study, we provided data on bark and whole wood samples in 2016 and separately measured 137 Cs concentrations in sapwood and heartwood samples from 2011 to 2016; we further discussed temporal trends in 137 Cs concentrations in each part of tree stems, particularly those in 137 Cs distributions between sapwood and heartwood, in relation to their species and site dependencies. Temporal trends in bark and whole wood samples collected from 2011 to 2016 were consistent with those reported in samples collected from 2011 to 2015. Temporal variations in 137 Cs concentrations in barks showed either a decreasing trend or no clear trend, implying that 137 Cs deposition in barks is inhomogeneous and that decontamination is relatively slow in some cases. Temporal trends in 137 Cs concentrations in sapwood, heartwood, and whole wood were different among species and also among sites within the same species. Relatively common trends within the same species, which were increasing, were observed in cedar heartwood, and in oak sapwood and whole wood. On the other hand, the ratio of 137 Cs concentration in heartwood to that in sapwood (fresh weight basis) was commonly increased to more than 2 in cedar, although distinct temporal trends were not found in the other species, for which the ratio was around 1 in cypress and pine and below 0.5 in oak, suggesting that 137 Cs transfer from sapwood to heartwood shows species dependency. Consequently, the species dependency of 137 Cs transfer within the tree appears easily, while that from the environment to the trees can be masked by various factors. Thus, prediction of 137 Cs concentrations in stem wood should be carried out carefully as it still requires investigations at multiple sites with a larger sample size and an understanding of the species-specific 137 Cs transfer mechanism. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

A review on the temporal pattern of deer-vehicle accidents: impact of seasonal, diurnal and lunar effects in cervids.

PubMed

Steiner, Wolfgang; Leisch, Friedrich; Hackländer, Klaus

2014-05-01

The increasing number of deer-vehicle-accidents (DVAs) and the resulting economic costs have promoted numerous studies on behavioural and environmental factors which may contribute to the quantity, spatiotemporal distribution and characteristics of DVAs. Contrary to the spatial pattern of DVAs, data of their temporal pattern is scarce and difficult to obtain because of insufficient accuracy in available datasets, missing standardization in data aquisition, legal terms and low reporting rates to authorities. Literature of deer-traffic collisions on roads and railways is reviewed to examine current understanding of DVA temporal trends. Seasonal, diurnal and lunar peak accident periods are identified for deer, although seasonal pattern are not consistent among and within species or regions and data on effects of lunar cycles on DVAs is almost non-existent. Cluster analysis of seasonal DVA data shows nine distinct clusters of different seasonal DVA pattern for cervid species within the reviewed literature. Studies analyzing the relationship between time-related traffic predictors and DVAs yield mixed results. Despite the seasonal dissimilarity, diurnal DVA pattern are comparatively constant in deer, resulting in pronounced DVA peaks during the hours of dusk and dawn frequently described as bimodal crepuscular pattern. Behavioural aspects in activity seem to have the highest impact in DVAs temporal trends. Differences and variations are related to habitat-, climatic- and traffic characteristics as well as effects of predation, hunting and disturbance. Knowledge of detailed temporal DVA pattern is essential for prevention management as well as for the application and evaluation of mitigation measures. Copyright © 2014 Elsevier Ltd. All rights reserved.

A 15-Year Review of Trends in Representation of Female Subjects in Islamic Bioethics Research.

PubMed

Hussain, Zeenat; Kuzian, Edyta; Hussain, Naveed

2017-02-01

Gender representation in Islamic bioethics research in the twenty-first century has not been studied. To study temporal trends in representation of female subjects in Islamic bioethics research, PubMed-listed publications on Islamic bioethics from years 2000 to 2014 were reviewed for gender participation in human subjects' research. There were temporal trends of increasing publications of Islamic bioethics-related human subjects' research (64 papers over 15 years; R 2  = 0.72; p < 0.0004). Female subjects were well represented with a trend toward increasing participation. This was true for women from Muslim-majority countries even in non-gender-focused studies over the past 15 years.

Scientific activities of Euro Chlor in monitoring and assessing naturally and man-made organohalogens.

PubMed

Lecloux, A J

2003-07-01

In this paper a review of the scientific activities and research programmes carried out by Euro Chlor, the European Federation of chlor-alkali producers is presented according to two main axes: marine risk assessments with statistical analysis of monitoring data, temporal trends of emission levels and environmental concentrations. The methodology applied in each field is briefly presented and then illustrated by several practical examples. As a large part of the uncertainties in assessing the risk of a chemical to a given species or ecosystem often comes from the difficulty in evaluating the exposure level, Euro Chlor has chosen to use a monitoring approach, the exposure level being estimated from a statistical analysis of measured concentrations levels in water and sediment from rivers, estuaries and coastal areas. As the modelling approach often used by the authorities to estimate the predicted environmental concentration value is starting from roughly estimated emission levels, Euro Chlor collated emissions data from about 80 production plants in order to reduce the uncertainty associated with the default values introduced in the modelling approach.A brief review of the European emission levels for chlorinated organic substances is given as well as the temporal trends of both emission and environmental levels. A methodology to quantify the trends in measured concentrations at local and regional scales is briefly described. The observed decreasing trends demonstrate the continuous progress made by the Euro Chlor member companies in protecting the environment.Finally, the problems linked to the simultaneous presence in the environment of naturally and man-made chlorinated substances are briefly reviewed. To stimulate further research in the field, two key questions are raised which have not yet found a satisfactory answer: how to quantify natural background levels and how to quantify global persistence in the environment?

Horseshoe crab spawning activity in Delaware Bay, USA, after harvest reduction: A mixed-model analysis

USGS Publications Warehouse

Smith, David R.; Robinson, Timothy J.

2015-01-01

A Delaware Bay, USA, standardized survey of spawning horseshoe crabs, Limulus polyphemus, was carried out in 1999 − 2013 through a citizen science network. Previous trend analyses of the data were at the state (DE or NJ) or bay-wide levels. Here, an alternative mixed-model regression analysis was used to estimate trends in female and male spawning densities at the beach level (n = 26) with the objective of inferring their causes. For females, there was no overall trend and no single explanation applies to the temporal and spatial patterns in their densities. Individual beaches that initially had higher densities tended to experience a decrease, while beaches that initially had lower densities tended to experience an increase. As a result, densities of spawning females at the end of the study period were relatively similar among beaches, suggesting a redistribution of females among the beaches over the study period. For males, there was a positive overall trend in spawning abundance from 1999 to 2013, and this increase occurred broadly among beaches. Moreover, the beaches with below-average initial male density tended to have the greatest increases. Possible explanations for these patterns include harvest reduction, sampling artifact, habitat change, density-dependent habitat selection, or mate selection. The broad and significant increase in male spawning density, which occurred after enactment of harvest controls, is consistent with the harvest reduction explanation, but there is no single explanation for the temporal or spatial pattern in female densities. These results highlight the continued value of a citizen-science-based spawning survey in understanding horseshoe crab ecology and conservation.

A User-Oriented Methodology for DInSAR Time Series Analysis and Interpretation: Landslides and Subsidence Case Studies

NASA Astrophysics Data System (ADS)

Notti, Davide; Calò, Fabiana; Cigna, Francesca; Manunta, Michele; Herrera, Gerardo; Berti, Matteo; Meisina, Claudia; Tapete, Deodato; Zucca, Francesco

2015-11-01

Recent advances in multi-temporal Differential Synthetic Aperture Radar (SAR) Interferometry (DInSAR) have greatly improved our capability to monitor geological processes. Ground motion studies using DInSAR require both the availability of good quality input data and rigorous approaches to exploit the retrieved Time Series (TS) at their full potential. In this work we present a methodology for DInSAR TS analysis, with particular focus on landslides and subsidence phenomena. The proposed methodology consists of three main steps: (1) pre-processing, i.e., assessment of a SAR Dataset Quality Index (SDQI) (2) post-processing, i.e., application of empirical/stochastic methods to improve the TS quality, and (3) trend analysis, i.e., comparative implementation of methodologies for automatic TS analysis. Tests were carried out on TS datasets retrieved from processing of SAR imagery acquired by different radar sensors (i.e., ERS-1/2 SAR, RADARSAT-1, ENVISAT ASAR, ALOS PALSAR, TerraSAR-X, COSMO-SkyMed) using advanced DInSAR techniques (i.e., SqueeSAR™, PSInSAR™, SPN and SBAS). The obtained values of SDQI are discussed against the technical parameters of each data stack (e.g., radar band, number of SAR scenes, temporal coverage, revisiting time), the retrieved coverage of the DInSAR results, and the constraints related to the characterization of the investigated geological processes. Empirical and stochastic approaches were used to demonstrate how the quality of the TS can be improved after the SAR processing, and examples are discussed to mitigate phase unwrapping errors, and remove regional trends, noise and anomalies. Performance assessment of recently developed methods of trend analysis (i.e., PS-Time, Deviation Index and velocity TS) was conducted on two selected study areas in Northern Italy affected by land subsidence and landslides. Results show that the automatic detection of motion trends enhances the interpretation of DInSAR data, since it provides an objective picture of the deformation behaviour recorded through TS and therefore contributes to the understanding of the on-going geological processes.

Using nestling plasma to assess long-term spatial and temporal concentrations of organochlorine compounds in bald eagles within Voyageurs National Park, Minnesota, USA

Treesearch

H. Tyler Pittman; William W. Bowerman; Leland H. Grim; Teryl G. Grubb; William C. Bridges; Michael R. Wierda

2015-01-01

The bald eagle (Haliaeetus leucocephalus) population at Voyageurs National Park (VNP) provides an opportunity to assess long-term temporal and spatial trends of persistent environmental contaminants. Nestling bald eagle plasma samples collected from 1997 to 2010 were analyzed for polychlorinated biphenyls (PCBs) and organochlorine pesticides. Trends of total PCBs,...

Trends in the capture fisheries in Cuyo East Pass, Philippines

USGS Publications Warehouse

San Diego, Tee-Jay A.; Fisher, William L.

2014-01-01

Findings are presented of a comprehensive analysis of time series catch and effort data from 2000 to 2006 collected from a multi-species, multi-gear and two-sector (municipal and commercial) capture fisheries in Cuyo East Pass, Philippines. Multivariate techniques were used to determine temporal variation in species composition and gear selectivity that corresponded with annual trends in catch and effort. Distinct annual variation in species composition was found for five fisheries classified according to sector-gear combination, corresponding decline in catch diversity, noted shifts in gears used, and an erratic CPUE trend as a result of catch variation.  These patterns and trends illustrate the occurrence of ecosystem overfishing for Cuyo East Pass.  Our approach provided a holistic representation of the fishing situation, condition of the fisheries and corresponding implications to the ecosystem, fitting well within the context of the ecosystem approach to fisheries management.

Incidence and mortality of lung cancer: global trends and association with socioeconomic status.

PubMed

Wong, Martin C S; Lao, Xiang Qian; Ho, Kin-Fai; Goggins, William B; Tse, Shelly L A

2017-10-30

We examined the correlation between lung cancer incidence/mortality and country-specific socioeconomic development, and evaluated its most recent global trends. We retrieved its age-standardized incidence rates from the GLOBOCAN database, and temporal patterns were assessed from global databases. We employed simple linear regression analysis to evaluate their correlations with Human Development Index (HDI) and Gross Domestic Product (GDP) per capita. The average annual percent changes (AAPC) of the trends were evaluated from join-point regression analysis. Country-specific HDI was strongly correlated with age-standardized incidence (r = 0.70) and mortality (r = 0.67), and to a lesser extent GDP (r = 0.24 to 0.55). Among men, 22 and 30 (out of 38 and 36) countries showed declining incidence and mortality trends, respectively; whilst among women, 19 and 16 countries showed increasing incidence and mortality trends, respectively. Among men, the AAPCs ranged from -2.8 to -0.6 (incidence) and -3.6 to -1.1 (mortality) in countries with declining trend, whereas among women the AAPC range was 0.4 to 8.9 (incidence) and 1 to 4.4 (mortality) in countries with increasing trend. Among women, Brazil, Spain and Cyprus had the greatest incidence increase, and all countries in Western, Southern and Eastern Europe reported increasing mortality. These findings highlighted the need for targeted preventive measures.

Temporal change and its spatial variety on land surface temperature and land use changes in the Red River Delta, Vietnam, using MODIS time-series imagery.

PubMed

Van Nguyen, On; Kawamura, Kensuke; Trong, Dung Phan; Gong, Zhe; Suwandana, Endan

2015-07-01

Temporal changes in the land surface temperature (LST) in urbanization areas are important for studying an urban heat island (UHI) and regional climate change. This study examined the LST trends under different land use categories in the Red River Delta, Vietnam, using the Moderate Resolution Imaging Spectroradiometer (MODIS) LST product (MOD11A2) and land cover type product (MCD12Q1) for 11 years (2002-2012). Smoothened time-series MODIS LST data were reconstructed by the Harmonic Analysis of Time Series (HANTS) algorithm. The reconstructed LST (maximum and minimum temperatures) was assessed using the hourly air temperature dataset in two land-based meteorological stations provided by the National Climatic Data Center (NCDC). Significant correlation was obtained between MODIS LST and the air temperature for the daytime (R (2) = 0.73, root mean square error [RMSE] = 1.66 °C) and night time (R (2) = 0.84, RMSE = 1.79 °C). Statistical analysis also showed that LST trends vary strongly depending on the land cover type. Forest, wetland, and cropland had a slight tendency to decline, whereas cropland and urban had sharper increases. In urbanized areas, these increasing trends are even more obvious. This is undeniable evidence of the negative impact of urbanization on a surface urban heat island (SUHI) and global warming.

Trends in chlorinated hydrocarbon levels in Hudson River basin sediments.

PubMed

Bopp, R F; Chillrud, S N; Shuster, E L; Simpson, H J; Estabrooks, F D

1998-08-01

Analysis of sections from dated sediment cores were used to establish geographic distributions and temporal trends of chlorinated hydrocarbon contaminant levels in sediments from natural waters of the Hudson River basin. Radiometric dating was based primarily on the depth distribution of 137(Cs) in the cores and on the occurrence of detectable levels of 7(Be) in surface sediment samples. Eighteen sampling sites included several along the main stem of the Hudson, its major tributaries, and components of the New York/New Jersey (NY/NJ) harbor complex. Drinking-water reservoirs were sampled to place upper limits on atmospheric inputs. Core sections were analyzed for polychlorinated biphenyls (PCBs), 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT)-derived compounds, chlordane, and dioxins. Sediment concentrations of most contaminants at most sites have decreased significantly since the mid-1960s. The data provide a basinwide perspective on major point-source inputs of PCBs to the upper Hudson River and of 2,3,7,8-tetrachlorodibenzo-p-dioxin and DDT to the lower Passaic River. Evidence was found for significant but poorly characterized sources of PCBs and chlordane to the western NY/NJ harbor, and of highly chlorinated dioxins to the upstream sites on the main stem of the Hudson. The results indicate that analysis of dated sediment samples is a most effective and efficient monitoring tool for the study of large-scale geographic and temporal trends in levels of particle-associated contaminants.

Association analysis between spatiotemporal variation of vegetation greenness and precipitation/temperature in the Yangtze River Basin (China).

PubMed

Cui, Lifang; Wang, Lunche; Singh, Ramesh P; Lai, Zhongping; Jiang, Liangliang; Yao, Rui

2018-05-23

The variation in vegetation greenness provides good understanding of the sustainable management and monitoring of land surface ecosystems. The present paper discusses the spatial-temporal changes in vegetation and controlling factors in the Yangtze River Basin (YRB) using Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI) for the period 2001-2013. Theil-Sen Median trend analysis, Pearson correlation coefficients, and residual analysis have been used, which shows decreasing trend of the annual mean NDVI over the whole YRB. Spatially, the regions with significant decreasing trends were mainly located in parts of central YRB, and pronounced increasing trends were observed in parts of the eastern and western YRB. The mean NDVI during spring and summer seasons increased, while it decreased during autumn and winter seasons. The seasonal mean NDVI shows spatial heterogeneity due to the vegetation types. The correlation analysis shows a positive relation between NDVI and temperature over most of the YRB, whereas NDVI and precipitation show a negative correlation. The residual analysis shows an increase in NDVI in parts of eastern and western YRB and the decrease in NDVI in the small part of Yangtze River Delta (YRD) and the mid-western YRB due to human activities. In general, climate factors were the principal drivers of NDVI variation in YRB in recent years.

Intellectual property analysis of holographic materials business

NASA Astrophysics Data System (ADS)

Reingand, Nadya; Hunt, David

2006-02-01

The paper presents an overview of intellectual property in the field of holographic photosensitive materials and highlights the possibilities offered by patent searching and analysis. Thousands of patent documents relevant to holographic materials have been uncovered by the study. The search was performed in the following databases: U.S. Patent Office, European Patent Office, and Japanese Patent Office for the time frame of 1971 through November 2005. The patent analysis has unveiled trends in patent temporal distribution, leading IP portfolios, companies competition within the holographic materials market and other interesting insights.

Intellectual property (IP) analysis of embossed hologram business

NASA Astrophysics Data System (ADS)

Hunt, David; Reingand, Nadya; Cantrell, Robert

2006-02-01

This paper presents an overview of patents and patent applications on security embossed holograms, and highlights the possibilities offered by patent searching and analysis. Thousands of patent documents relevant to embossed holograms were uncovered by the study. The search was performed in the following databases: U.S. Patent Office, European Patent Office, Japanese Patent Office and Korean Patent Office for the time frame from 1971 through November 2005. The patent analysis unveils trends in patent temporal distribution, patent families formation, significant technological coverage within the embossed holography market and other interesting insights.

Temporal Trends and Pattern Changes of Short- and Medium-Chain Chlorinated Paraffins in Marine Mammals from the South China Sea over the Past Decade.

PubMed

Zeng, Lixi; Lam, James C W; Wang, Yawei; Jiang, Guibin; Lam, Paul K S

2015-10-06

Temporal trends of short- (SCCPs) and medium-chain chlorinated paraffins (MCCPs) were examined in blubber samples of 50 finless porpoises (Neophocaena phocaenoides) and 25 Indo-Pacific humpback dolphins (Sousa chinensis) collected from the South China Sea between 2004 and 2014. Elevated levels of SCCPs and MCCPs were detected in all blubber samples of both cetacean species. Concentrations of SCCPs ranged from 280 to 3900 ng·g(-1) dry weight (dw) in porpoises and from 430 to 9100 ng·g(-1) dw in dolphins, while concentrations of MCCPs ranged from 320 to 8600 ng·g(-1) dw in porpoises and from 530 to 23 000 ng·g(-1) dw in dolphins. Significantly higher concentrations were present in dolphins than porpoises due to their exposure levels in their living habitats. Strongly linear correlations existed between SCCPs and MCCPs, but there were no significant concentration differences between the genders of the two cetacean species in the same sampling year. Significantly temporal increasing trends of ∑SCCPs and ∑MCCPs have been observed in both porpoise and dolphin samples over the past decade, which reflect the influence of histories of production and usage on the bioaccumulation of CPs in marine mammals in China. An apparent temporal shift trend from SCCPs to MCCPs was also observed in CP accumulation profiles. Complex environmental fractionation from localized sources in the study region via atmospheric transport, oceanic/offshore water transport, and trophic transfer have resulted in different CP accumulation levels and homologue patterns in the two cetacean species. This is the first report of systematic temporal trends of SCCPs and MCCPs in marine mammals.

Temporal trends in dancing among adults between 1994 and 2012: The Health Survey for England.

PubMed

Vassallo, Amy Jo; Hiller, Claire E; Pappas, Evangelos; Stamatakis, Emmanuel

2018-01-01

The benefits of physical activity are established, however, increasing population physical activity levels remains a challenge. Participating in activities that are enjoyable and multidimensional, such as dancing, are associated with better adherence. However, the extent to which the general population participates in dancing and its temporal trends has not been well studied. The aim of this study was to investigate temporal trends and patterns and correlates of dance participation in England from 1994 to 2012 using a series of large nationally representative surveys. We used data from the Health Survey for England 1994, 1997, 1998, 1999, 2003, 2004, 2006, 2008 and 2012 to examine dance temporal trends. Temporal trends data were age-standardized and correlates of dance participation were examined for males and females over each study year. Changes in population prevalence of dance participation were determined using multiple logistical regression with 1997 as the reference year. Of all survey participants (n=98,178) 7.8% (95%CI: 7.63-7.96) reported dance participation. There was a marked steady decrease over time, with the steepest decline from 2003 onwards. The multivariable-adjusted odds ratios for dance participation were 0.51 for males (95%CI 0.408-0.630, p<0.001) and 0.69 for females (95%CI: 0.598-0.973, p<0.001) in 2012 compared to 1997. Dance participation in adults in England has decreased markedly over time. This study suggests that dance is not being adequately utilized as a health enhancing physical activity, and therefore further research and resources should be dedicated to supporting dance in the community. Copyright © 2017 Elsevier Inc. All rights reserved.

Recent shifts in Himalayan vegetation activity trends in response to climatic change and environmental drivers

NASA Astrophysics Data System (ADS)

Mishra, N. B.; Mainali, K. P.

2016-12-01

Climatic changes along with anthropogenic disturbances are causing dramatic ecological impacts in mid to high latitude mountain vegetation including in the Himalayas which are ecologically sensitive environments. Given the challenges associated with in situ vegetation monitoring in the Himalayas, remote sensing based quantification of vegetation dynamics can provide essential ecological information on changes in vegetation activity that may consist of alternative sequence of greening and/or browning periods. This study utilized a trend break analysis procedure for detection of monotonic as well as abrupt (either interruption or reversal) trend changes in smoothed normalized difference vegetation index satellite time-series data over the Himalayas. Overall, trend breaks in vegetation greenness showed high spatio-temporal variability in distribution considering elevation, ecoregion and land cover/use stratifications. Interrupted greening was spatially most dominant in all Himalayan ecoregions followed by abrupt browning. Areas showing trend reversal and monotonic trends appeared minority. Trend type distribution was strongly dependent on elevation as majority of greening (with or without interruption) occurred at lower elevation areas at higher elevation were dominantly. Ecoregion based stratification of trend types highlighted some exception to this elevational dependence as high altitude ecoregions of western Himalayas showed significantly less browning compared to the ecoregions in eastern Himalaya. Land cover/use based analysis of trend distribution showed that interrupted greening was most dominant in closed needleleafed forest following by rainfed cropland and mosaic croplands while interrupted browning most dominant in closed to open herbaceous vegetation found at higher elevation areas followed by closed needleleafed forest and closed to open broad leafed evergreen forests. Spatial analysis of trend break timing showed that for majority of areas experiencing interrupted greening, break in trend occurred later compared to areas with interrupted browning where break trend was observed much earlier. These results have significant implications for environmental management in the context of climate change and ecosystem dynamics in the Himalayas.

Variability of African Farming Systems from Phenological Analysis of NDVI Time Series

NASA Technical Reports Server (NTRS)

Vrieling, Anton; deBeurs, K. M.; Brown, Molly E.

2011-01-01

Food security exists when people have access to sufficient, safe and nutritious food at all times to meet their dietary needs. The natural resource base is one of the many factors affecting food security. Its variability and decline creates problems for local food production. In this study we characterize for sub-Saharan Africa vegetation phenology and assess variability and trends of phenological indicators based on NDVI time series from 1982 to 2006. We focus on cumulated NDVI over the season (cumNDVI) which is a proxy for net primary productivity. Results are aggregated at the level of major farming systems, while determining also spatial variability within farming systems. High temporal variability of cumNDVI occurs in semiarid and subhumid regions. The results show a large area of positive cumNDVI trends between Senegal and South Sudan. These correspond to positive CRU rainfall trends found and relate to recovery after the 1980's droughts. We find significant negative cumNDVI trends near the south-coast of West Africa (Guinea coast) and in Tanzania. For each farming system, causes of change and variability are discussed based on available literature (Appendix A). Although food security comprises more than the local natural resource base, our results can perform an input for food security analysis by identifying zones of high variability or downward trends. Farming systems are found to be a useful level of analysis. Diversity and trends found within farming system boundaries underline that farming systems are dynamic.

Spatio-Temporal Trends of Fire in Slash and Burn Agriculture Landscape: A Case Study from Nagaland, India

NASA Astrophysics Data System (ADS)

Padalia, H.; Mondal, P. P.

2014-11-01

Increasing incidences of fire from land conversion and residue burning in tropics is the major concern in global warming. Spatial and temporal monitoring of trends of fire incidences is, therefore, significant in order to determine contribution of carbon emissions from slash and burn agriculture. In this study, we analyzed time-series Terra / Aqua MODIS satellite hotspot products from 2001 to 2013 to derive intra- and inter-annual trends in fire incidences in Nagaland state, located in the Indo-Burma biodiversity hotspot. Time-series regression was applied to MODIS fire products at variable spatial scales in GIS. Significance of change in fire frequency at each grid level was tested using t statistic. Spatial clustering of higher or lower fire incidences across study area was determined using Getis-OrdGi statistic. Maximum fire incidences were encountered in moist mixed deciduous forests (46%) followed by secondary moist bamboo brakes (30%). In most parts of the study area fire incidences peaked during March while in warmer parts (e.g. Mon district dominated by indigenous people) fire activity starts as early as during November and peaks in January. Regression trend analysis captured noticeable areas with statistically significant positive (e.g. Mokokchung, Wokha, Mon, Tuensang and Kiphire districts) and negative (e.g. Kohima and north-western part of Mokokchung district) inter-annual fire frequency trends based on area-based aggregation of fire occurrences at different grid sizes. Localization of spatial clusters of high fire incidences was observed in Mokokchung, Wokha, Mon,Tuensang and Kiphire districts.

Volumetric Trends Associated with MR-guided Stereotactic Laser Amygdalohippocampectomy in Mesial Temporal Lobe Epilepsy

PubMed Central

Patel, Nitesh V; Sundararajan, Sri; Keller, Irwin; Danish, Shabbar

2018-01-01

Objective: Magnetic resonance (MR)-guided stereotactic laser amygdalohippocampectomy is a minimally invasive procedure for the treatment of refractory epilepsy in patients with mesial temporal sclerosis. Limited data exist on post-ablation volumetric trends associated with the procedure. Methods: 10 patients with mesial temporal sclerosis underwent MR-guided stereotactic laser amygdalohippocampectomy. Three independent raters computed ablation volumes at the following time points: pre-ablation (PreA), immediate post-ablation (IPA), 24 hours post-ablation (24PA), first follow-up post-ablation (FPA), and greater than three months follow-up post-ablation (>3MPA), using OsiriX DICOM Viewer (Pixmeo, Bernex, Switzerland). Statistical trends in post-ablation volumes were determined for the time points. Results: MR-guided stereotactic laser amygdalohippocampectomy produces a rapid rise and distinct peak in post-ablation volume immediately following the procedure. IPA volumes are significantly higher than all other time points. Comparing individual time points within each raters dataset (intra-rater), a significant difference was seen between the IPA time point and all others. There was no statistical difference between the 24PA, FPA, and >3MPA time points. A correlation analysis demonstrated the strongest correlations at the 24PA (r=0.97), FPA (r=0.95), and 3MPA time points (r=0.99), with a weaker correlation at IPA (r=0.92). Conclusion: MR-guided stereotactic laser amygdalohippocampectomy produces a maximal increase in post-ablation volume immediately following the procedure, which decreases and stabilizes at 24 hours post-procedure and beyond three months follow-up. Based on the correlation analysis, the lower inter-rater reliability at the IPA time point suggests it may be less accurate to assess volume at this time point. We recommend post-ablation volume assessments be made at least 24 hours post-selective ablation of the amygdalohippocampal complex (SLAH).

Analysis of the spatio-temporal variability of seawater quality in the southeastern Arabian Gulf.

PubMed

Mezhoud, Nahla; Temimi, Marouane; Zhao, Jun; Al Shehhi, Maryam Rashed; Ghedira, Hosni

2016-05-15

In this study, seawater quality measurements, including salinity, sea surface temperature (SST), chlorophyll-a (Chl-a), Secchi disk depth (SDD), pH, and dissolved oxygen (DO), were made from June 2013 to November 2014 at 52 stations in the southeastern Arabian Gulf. Significant variability was noticed for all collected parameters. Salinity showed a decreasing trend, and Chl-a, DO, pH, and SDD demonstrated increasing trends from shallow onshore stations to deep offshore ones, which could be attributed to variations of ocean circulation and meteorological conditions from onshore to offshore waters, and the likely effects of desalination plants along the coast. Salinity and temperature were high in summer and low in winter while Chl-a, SDD, pH, and DO indicated an opposite trend. The CTD profiles showed vertically well-mixed structures. Qualitative analysis of phytoplankton showed a high diversity of species without anomalous species found except in Ras Al Khaimah stations where diatoms were the dominating ones. Copyright © 2016 Elsevier Ltd. All rights reserved.

Decreasing spatial variability in precipitation extremes in southwestern China and the local/large-scale influencing factors

NASA Astrophysics Data System (ADS)

Liu, Meixian; Xu, Xianli; Sun, Alex

2015-07-01

Climate extremes can cause devastating damage to human society and ecosystems. Recent studies have drawn many conclusions about trends in climate extremes, but few have focused on quantitative analysis of their spatial variability and underlying mechanisms. By using the techniques of overlapping moving windows, the Mann-Kendall trend test, correlation, and stepwise regression, this study examined the spatial-temporal variation of precipitation extremes and investigated the potential key factors influencing this variation in southwestern (SW) China, a globally important biodiversity hot spot and climate-sensitive region. Results showed that the changing trends of precipitation extremes were not spatially uniform, but the spatial variability of these precipitation extremes decreased from 1959 to 2012. Further analysis found that atmospheric circulations rather than local factors (land cover, topographic conditions, etc.) were the main cause of such precipitation extremes. This study suggests that droughts or floods may become more homogenously widespread throughout SW China. Hence, region-wide assessments and coordination are needed to help mitigate the economic and ecological impacts.

Long-term analysis of Zostera noltei: A retrospective approach for understanding seagrasses' dynamics.

PubMed

Calleja, Felipe; Galván, Cristina; Silió-Calzada, Ana; Juanes, José A; Ondiviela, Bárbara

2017-09-01

Long-term studies are necessary to establish trends and to understand seagrasses' spatial and temporal dynamic. Nevertheless, this type of research is scarce, as the required databases are often unavailable. The objectives of this study are to create a method for mapping the seagrass Zostera noltei using remote sensing techniques, and to apply it to the characterization of the meadows' extension trend and the potential drivers of change. A time series was created using a novel method based on remote sensing techniques that proved to be adequate for mapping the seagrass in the emerged intertidal. The meadows seem to have a decreasing trend between 1984 and the early 2000s, followed by an increasing tendency that represents a recovery in the extension area of the species. This 30-year analysis demonstrated the Z. noltei's recovery in the study site, similar to that in other estuaries nearby and contrary to the worldwide decreasing behavior of seagrasses. Copyright © 2017 Elsevier Ltd. All rights reserved.

Level and temporal trend of perfluoroalkyl acids in Greenlandic Inuit.

PubMed

Long, Manhai; Bossi, Rossana; Bonefeld-Jørgensen, Eva C

2012-03-19

Perfluoroalkyl acids (PFAAs) have been detected in human blood, breast milk and umbilical cord blood across the globe. PFAAs do accumulate in the marine food chain in Arctic regions. In Greenland, increasing PFAA concentrations were observed during 1982-2006 in ringed seals and polar bears. However, until now, no data have been reported for PFAAs in Greenlandic Inuit. This study assesses the level and temporal trend of serum PFAAs in Greenlandic Inuit. Cross-section and temporal time trend survey. Serum PFAA levels were determined in 284 Inuit from different Greenlandic districts using liquid chromatography-tandem mass spectrometry with electrospray ionization. The temporal time trend of serum PFAAs in Nuuk Inuit during 1998-2005 and the correlation between serum PFAAs and legacy persistent organic pollutants (POPs) were explored. Serum PFAA levels were higher in Nuuk Inuit than in non-Nuuk Inuit. Within the same district, higher PFAA levels were observed for males. An age-dependent, increasing trend of serum PFAA levels in the period from 1998-2005 was observed for Nuuk Inuit. For the pooled gender data, no significant association between PFAAs and legacy POPs was observed for Nuuk Inuit while for non-Nuuk Inuit this correlation was significant. No correlation between PFAAs and legacy POPs was found for male Inuit, whereas significant correlation was observed both for pooled female Inuit and for non-Nuuk Inuit females. We suggest that sources other than seafood intake might contribute to the observed higher PFAA levels in Nuuk Inuit compared to the pooled non-Nuuk Inuit.

Population surveys in Greenland 1993-2009: temporal trend of PCBs and pesticides in the general Inuit population by age and urbanisation.

PubMed

Bjerregaard, Peter; Pedersen, Henning Sloth; Nielsen, Nina O; Dewailly, Eric

2013-06-01

The purpose of the study was to analyse temporal trends (1993-2009) of the concentrations of organochlorine contaminants (14 congeners of polychlorinated biphenyls (PCB) and 11 pesticides) in the blood of Greenland Inuit according to age and urbanisation. Statistical determinants for the contaminant concentrations included (for PCB congener 153) age (Δr(2)=0.35), marine diet (Δr(2)=0.10), smoking (Δr(2)=0.02), and sex (Δr(2)=0.01) with comparable results for other organochlorine contaminants. After adjustment for age, diet, smoking, and sex a significant decreasing trend was present for all contaminants ranging from 41% for mirex to 56% for hexachlorobenzene. The temporal trend was most pronounced among participants below the age of 65 years. The decrease started later in villages than in towns. The decrease was present in all age groups and in the capital, other towns, and villages. The decrease is probably due to a combination of reduced concentrations of the contaminants in the wildlife and a slight temporal reduction in the consumption of marine mammals. The significant downwards trend of legacy POPs shows that the legislation works but it must be kept in mind that according to the cumulated scientific evidence there are a multitude of non-regulated persistent organic contaminants in the diet as well as high levels of methylmercury. Copyright © 2013 Elsevier B.V. All rights reserved.

Cerebral responses to innocuous somatic pressure stimulation following aerobic exercise rehabilitation in chronic pain patients: a functional magnetic resonance imaging study

PubMed Central

Micalos, Peter S; Korgaonkar, Mayuresh S; Drinkwater, Eric J; Cannon, Jack; Marino, Frank E

2014-01-01

Objective The purpose of this research was to assess the functional brain activity and perceptual rating of innocuous somatic pressure stimulation before and after exercise rehabilitation in patients with chronic pain. Materials and methods Eleven chronic pain patients and eight healthy pain-free controls completed 12 weeks of supervised aerobic exercise intervention. Perceptual rating of standardized somatic pressure stimulation (2 kg) on the right anterior mid-thigh and brain responses during functional magnetic resonance imaging (fMRI) were assessed at pre- and postexercise rehabilitation. Results There was a significant difference in the perceptual rating of innocuous somatic pressure stimulation between the chronic pain and control groups (P=0.02) but no difference following exercise rehabilitation. Whole brain voxel-wise analysis with correction for multiple comparisons revealed trends for differences in fMRI responses between the chronic pain and control groups in the superior temporal gyrus (chronic pain > control, corrected P=0.30), thalamus, and caudate (control > chronic, corrected P=0.23). Repeated measures of the regions of interest (5 mm radius) for blood oxygen level-dependent signal response revealed trend differences for superior temporal gyrus (P=0.06), thalamus (P=0.04), and caudate (P=0.21). Group-by-time interactions revealed trend differences in the caudate (P=0.10) and superior temporal gyrus (P=0.29). Conclusion Augmented perceptual and brain responses to innocuous somatic pressure stimulation were shown in the chronic pain group compared to the control group; however, 12-weeks of exercise rehabilitation did not significantly attenuate these responses. PMID:25210471

A comprehensive overview of the spatial and temporal variability of apple bud dormancy release and blooming phenology in Western Europe

NASA Astrophysics Data System (ADS)

Legave, Jean Michel; Blanke, Michael; Christen, Danilo; Giovannini, Daniela; Mathieu, Vincent; Oger, Robert

2013-03-01

In the current context of global warming, an analysis is required of spatially-extensive and long-term blooming data in fruit trees to make up for insufficient information on regional-scale blooming changes and determinisms that are key to the phenological adaptation of these species. We therefore analysed blooming dates over long periods at climate-contrasted sites in Western Europe, focusing mainly on the Golden Delicious apple that is grown worldwide. On average, blooming advances were more pronounced in northern continental (10 days) than in western oceanic (6-7 days) regions, while the shortest advance was found on the Mediterranean coastline. Temporal trends toward blooming phase shortenings were also observed in continental regions. These regional differences in temporal variability across Western Europe resulted in a decrease in spatial variability, i.e. shorter time intervals between blooming dates in contrasted regions (8-10-day decrease for full bloom between Mediterranean and continental regions). Fitted sequential models were used to reproduce phenological changes. Marked trends toward shorter simulated durations of forcing period (bud growth from dormancy release to blooming) and high positive correlations between these durations and observed blooming dates support the notion that blooming advances and shortenings are mainly due to faster satisfaction of the heating requirement. However, trends toward later dormancy releases were also noted in oceanic and Mediterranean regions. This could tend toward blooming delays and explain the shorter advances in these regions despite similar or greater warming. The regional differences in simulated chilling and forcing periods were consistent with the regional differences in temperature increases.

Using Dynamic Time Warping and Data Forensics to Examine Tradeoffs among Land-Energy-Water Networks Across the Conterminous United States

NASA Astrophysics Data System (ADS)

McManamay, R.; Allen, M. R.; Piburn, J.; Sanyal, J.; Stewart, R.; Bhaduri, B. L.

2017-12-01

Characterizing interdependencies among land-energy-water sectors, their vulnerabilities, and tipping points, is challenging, especially if all sectors are simultaneously considered. Because such holistic system behavior is uncertain, largely unmodeled, and in need of testable hypotheses of system drivers, these dynamics are conducive to exploratory analytics of spatiotemporal patterns, powered by tools, such as Dynamic Time Warping (DTW). Here, we conduct a retrospective analysis (1950 - 2010) of temporal trends in land use, energy use, and water use within US counties to identify commonalities in resource consumption and adaptation strategies to resource limitations. We combine existing and derived data from statistical downscaling to synthesize a temporally comprehensive land-energy-water dataset at the US county level and apply DTW and subsequent hierarchical clustering to examine similar temporal trends in resource typologies for land, energy, and water sectors. As expected, we observed tradeoffs among water uses (e.g., public supply vs irrigation) and land uses (e.g., urban vs ag). Strong associations between clusters amongst sectors reveal tight system interdependencies, whereas weak associations suggest unique behaviors and potential for human adaptations towards disruptive technologies and less resource-dependent population growth. Our framework is useful for exploring complex human-environmental system dynamics and generating hypotheses to guide subsequent energy-water-nexus research.

Spatial and temporal variations of wind erosion climatic erosivity in the farming-pastoral zone of Northern China

NASA Astrophysics Data System (ADS)

Yue, Shuping; Yang, Ruixin; Yan, Yechao; Yang, Zhengwei; Wang, Dandan

2018-03-01

Wind erosion climatic erosivity is an important parameter to assess the possible effects of climatic conditions on wind erosion. In this paper, the wind erosion climatic factor (C-factor), which was used to quantify the wind erosion climatic erosivity, was calculated for the period 1960-2014 based on monthly meteorological data collected from 101 stations in the farming-pastoral zone of Northern China. The Mann-Kendall (M-K) test, trend analysis, and geostatistical analysis methods were used to explore the spatial and temporal characteristics of the wind erosion climatic erosivity in this region. The result suggests that the annual C-factor, with a maximum of 76.05 in 1969 and a minimum of 26.57 in 2007, has a significant decreasing trend over the past 55 years. Strong seasonality in the C-factor was found, with the highest value in spring, which accounts for a significant proportion of the annual C-factor (41.46%). However, the coefficient of variation of the seasonal C-factor reaches a maximum in winter and a minimum in spring. The mean annual C-factor varies substantially across the region. Areas with high values of the mean annual C-factor (C ≥ 100) are located in Ulanqab and Dingxi, while areas with low values (C ≤ 10) lie in Lanzhou, Linxia, Dingxi, Xining, and Chengde. Spatial analysis on the trend of the C-factor reveals that 81% of the stations show statistically significant decreases at a 90% confidence level. An examination of the concentration ratio of the C-factor shows that the wind erosion climatic erosivity is concentrated in spring, especially in April, which makes this period particularly important for implementing soil conservation measures.

National trends in anterior cervical fusion procedures.

PubMed

Marawar, Satyajit; Girardi, Federico P; Sama, Andrew A; Ma, Yan; Gaber-Baylis, Licia K; Besculides, Melanie C; Memtsoudis, Stavros G

2010-07-01

Population-based database analysis. To analyze trends in patient- and healthcare-system-related characteristics, utilization and outcomes associated with anterior cervical spine fusions. Anterior cervical decompression and spine fusion (ACDF) is one of the most commonly performed surgical procedures of the spine. However, few data analyzing trends in patient- and healthcare-system-related characteristics, utilization and outcomes exist. Data from 1990 to 2004 collected in the National Hospital Discharge Survey were accessed. ACDF procedures were identified. Five-year periods of interest (POI) were created for temporal analysis and changes in the prevalence and utilization of this procedure as well as in patient- and healthcare-system-related variables were examined. The changes in the occurrence of procedure-related complications were evaluated. An estimated total of 771,932 discharges after ACDF were identified. Temporally, an almost 8-fold increase in total prevalence was accompanied by a similar increase in utilization (23/100.000 civilians/POI to 157/100.000/civilians/POI). The highest increase in utilization was observed in those > or =65 years (28-fold). Average age increased from 47.2 years to 50.5 years over time. Length of hospital stay decreased from 5.17 days to 2.38 days. Overall procedure-related complication rates decreased from 4.6% to 3.03%. The prevalence of hypertension, diabetes mellitus, hypercholesterolemia, obesity, pulmonary, and coronary artery increased over time among patients undergoing ACDF. Despite limitations inherent to secondary analysis of large databases, we identified a number of significant changes in the utilization, demographics, and outcomes associated with ACDF, which can be used to assess the effect of changes in medical care, direct health care resources, and future research. The effect of the increased prevalence of comorbidities on medical practice remains to be evaluated. Further studies are necessary to evaluate causal relationships.

Text Stream Trend Analysis using Multiscale Visual Analytics with Applications to Social Media Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steed, Chad A; Beaver, Justin M; BogenII, Paul L.

In this paper, we introduce a new visual analytics system, called Matisse, that allows exploration of global trends in textual information streams with specific application to social media platforms. Despite the potential for real-time situational awareness using these services, interactive analysis of such semi-structured textual information is a challenge due to the high-throughput and high-velocity properties. Matisse addresses these challenges through the following contributions: (1) robust stream data management, (2) automated sen- timent/emotion analytics, (3) inferential temporal, geospatial, and term-frequency visualizations, and (4) a flexible drill-down interaction scheme that progresses from macroscale to microscale views. In addition to describing thesemore » contributions, our work-in-progress paper concludes with a practical case study focused on the analysis of Twitter 1% sample stream information captured during the week of the Boston Marathon bombings.« less

Dry spell trend analysis in Kenya and the Murray Darling Basin using daily rainfall

NASA Astrophysics Data System (ADS)

Muita, R. R.; van Ogtrop, F. F.; Vervoort, R. W.

2012-04-01

Important agricultural areas in Kenya and the Murray Darling Basin (MDB) in Australia are largely semi-arid to arid. Persistent dry periods and timing of dry spells directly impact the availability of soil moisture and hence crop production in these regions. Most studies focus on the analysis of dry spell lengths at an annual scale. However, timing and length of dry spells at finer temporal scales is more beneficial for cropping when considering a trade-off between the time scale and the ability to analyse dry spell length. The aim of this study was to analyse the interannual and intra annual variations in dry spell lengths in the regions to inform crop management. This study analysed monthly dry spells based on daily rainfall for 1961-2010 on a limited dataset of 13 locations in Kenya and 17 locations in the MDB. This dataset was the most consistent across both regions and future analysis will incorporate more stations and longer time periods where available. Dry spell lengths were analysed by month and year and trends in monthly and annual dry spell lengths were analysed using Generalised Linear Models (GLM) and the Mann Kendall test (MK). Overall, monthly dryspell lengths are right skewed with higher frequency of shorter dryspells (3-25 days). In Kenya, significant increases in mean dry spell lengths (p≤0.02) are observed in inland arid-to semi humid locations but this temporal trend appears to decrease in highland and the coastal regions. Analysis of the MDB stations suggests changes in seasonality. For example, spatial trends suggest a North-South increase in dry spell length in summer (December - February), but a shortening after February. Generally, the GLM and MK results are similar in the two regions but the MK test tends to give higher values of positive slope coefficients and lower values for negative coefficients compared to GLM. This may limit the ability of finding the best estimates for model coefficients. Previous studies in Australia and Kenya have relied on continuous climatic indices based on global climate models and stochastic processes resulting in limited and mixed results. For agronomical purposes, our results show that direct assessment of dry spells lengths from daily rainfall also indicates changes in dry spells trends in Kenya and the MDB and that such an analysis is easy to use and requires limited assumptions. This initial analysis identifies significant increasing trends in the dry spell lengths in some areas and periods in Kenya and the MDB. This has major implications for crop production in these regions and it is recommended that this information be incorporated in the regions' management decisions. KEY WORDS: monthly dry spell length; Generalized Linear Models; Mann -Kendall test; month; Kenya, Murray Darling Basin (MDB).

Trend Change Detection in NDVI Time Series: Effects of Inter-Annual Variability and Methodology

NASA Technical Reports Server (NTRS)

Forkel, Matthias; Carvalhais, Nuno; Verbesselt, Jan; Mahecha, Miguel D.; Neigh, Christopher S.R.; Reichstein, Markus

2013-01-01

Changing trends in ecosystem productivity can be quantified using satellite observations of Normalized Difference Vegetation Index (NDVI). However, the estimation of trends from NDVI time series differs substantially depending on analyzed satellite dataset, the corresponding spatiotemporal resolution, and the applied statistical method. Here we compare the performance of a wide range of trend estimation methods and demonstrate that performance decreases with increasing inter-annual variability in the NDVI time series. Trend slope estimates based on annual aggregated time series or based on a seasonal-trend model show better performances than methods that remove the seasonal cycle of the time series. A breakpoint detection analysis reveals that an overestimation of breakpoints in NDVI trends can result in wrong or even opposite trend estimates. Based on our results, we give practical recommendations for the application of trend methods on long-term NDVI time series. Particularly, we apply and compare different methods on NDVI time series in Alaska, where both greening and browning trends have been previously observed. Here, the multi-method uncertainty of NDVI trends is quantified through the application of the different trend estimation methods. Our results indicate that greening NDVI trends in Alaska are more spatially and temporally prevalent than browning trends. We also show that detected breakpoints in NDVI trends tend to coincide with large fires. Overall, our analyses demonstrate that seasonal trend methods need to be improved against inter-annual variability to quantify changing trends in ecosystem productivity with higher accuracy.

Dynamic Assessment on the Landscape Patterns and Spatio-temporal Change in the mainstream of Tarim River

NASA Astrophysics Data System (ADS)

Zhang, Hui; Xue, Lianqing; Yang, Changbing; Chen, Xinfang; Zhang, Luochen; Wei, Guanghui

2018-01-01

The Tarim River (TR), as the longest inland river at an arid area in China, is a typical regions of vegetation variation research and plays a crucial role in the sustainable development of regional ecological environment. In this paper, the newest dataset of MODND1M NDVI, at a resolution of 500m, were applied to calculate vegetation index in growing season during the period 2000-2015. Using a vegetation coverage index, a trend line analysis, and the local spatial autocorrelation analysis, this paper investigated the landscape patterns and spatio-temporal variation of vegetation coverage at regional and pixel scales over mainstream of the Tarim River, Xinjiang. The results showed that (1) The bare land area on both sides of Tarim River appeared to have a fluctuated downward trend and there were two obvious valley values in 2005 and 2012. (2) Spatially, the vegetation coverage improved areas is mostly distributed in upstream and the degraded areas is mainly distributed in the left bank of midstream and the end of Tarim River during 2000-2005. (3) The local spatial auto-correlation analysis revealed that vegetation coverage was spatially positive autocorrelated and spatial concentrated. The high-high self-related areas are mainly distributed in upstream, where vegetation cover are relatively good, and the low-low self-related areas are mostly with lower vegetation cover in the lower reaches of Tarim River.

Spatial and temporal variation of rainfall trends of Sri Lanka

NASA Astrophysics Data System (ADS)

Wickramagamage, P.

2016-08-01

This study was based on daily rainfall data of 48 stations distributed over the entire island covering a 30-year period from 1981 to 2010. Data analysis was done to identify the spatial pattern of rainfall trends. The methods employed in data analysis are linear regression and interpolation by Universal Kriging and Radial Basis function. The slope of linear regression curves of 48 stations was used in interpolation. The regression coefficients show spatially and seasonally variable positive and negative trends of annual and seasonal rainfall. About half of the mean annual pentad series show negative trends, while the rest shows positive trends. By contrast, the rainfall trends of the Southwest Monsoon (SWM) season are predominantly negative throughout the country. The first phase of the Northeast Monsoon (NEM1) displays downward trends everywhere, with the exception of the Southeastern coastal area. The strongest negative trends were found in the Northeast and in the Central Highlands. The second phase (NEM2) is mostly positive, except in the Northeast. The Inter-Monsoon (IM) periods have predominantly upward trends almost everywhere, but still the trends in some parts of the Highlands and Northeast are negative. The long-term data at Watawala Nuwara Eliya and Sandringham show a consistent decline in the rainfall over the last 100 years, particularly during the SWM. There seems to be a faster decline in the rainfall in the last 3 decades. These trends are consistent with the observations in India. It is generally accepted that there has been changes in the circulation pattern. Weakening of the SWM circulation parameters caused by global warming appears to be the main causes of recent changes. Effect of the Asian Brown Cloud may also play a role in these changes.

Spatial and temporal snowpack variation in the crown of the continent ecosystem

USGS Publications Warehouse

Selkowitz, D.J.; Fagre, D.B.; Reardon, B.A.

2002-01-01

Snowpack related ecosystem changes such as glacier recession and alpine treeline advance have been documented in the Crown of the Continent Ecosystem (CCE) over the course of the previous 150 years. Using data from the Natural Resource Conservation Service's SNOTEL sites and snow course surveys, we examined the spatial and temporal variation in snowpack in the region. SNOTEL data suggest CCE snowpacks are larger and more persistent than in most regions of the Western U.S., and that water year precipitation, rather than mean temperature, is the primary control on April 1 snow water equivalent (SWE). Snow course data indicate a statistically significant downward trend in mean April 1 SWE for the period 1950-2001 but no statistically significant trend in mean May 1 SWE for the longer period 1922-2001. Further analysis reveals that variations in both April 1 and May 1 mean SWE are closely tied to the Pacific Decadal Oscillation, an ENSO-like interdecadal pattern of Pacific Ocean climate variability. Despite no significant trend in mean May 1 SWE between 1922-2001, glaciers in Glacier National Park receded steadily during this period, implying changing climatic conditions crossed a threshold for glacier mass balance maintenace sometime between the Little Ice Age glacial maxima and 1922.

Spatial and temporal analysis of Air Pollution Index and its timescale-dependent relationship with meteorological factors in Guangzhou, China, 2001-2011.

PubMed

Li, Li; Qian, Jun; Ou, Chun-Quan; Zhou, Ying-Xue; Guo, Cui; Guo, Yuming

2014-07-01

There is an increasing interest in spatial and temporal variation of air pollution and its association with weather conditions. We presented the spatial and temporal variation of Air Pollution Index (API) and examined the associations between API and meteorological factors during 2001-2011 in Guangzhou, China. A Seasonal-Trend Decomposition Procedure Based on Loess (STL) was used to decompose API. Wavelet analyses were performed to examine the relationships between API and several meteorological factors. Air quality has improved since 2005. APIs were highly correlated among five monitoring stations, and there were substantial temporal variations. Timescale-dependent relationships were found between API and a variety of meteorological factors. Temperature, relative humidity, precipitation and wind speed were negatively correlated with API, while diurnal temperature range and atmospheric pressure were positively correlated with API in the annual cycle. Our findings should be taken into account when determining air quality forecasts and pollution control measures. Copyright © 2014 Elsevier Ltd. All rights reserved.

Temporal analysis of vegetation indices related to biophysical parameters using Sentinel 2A images to estimate maize production

NASA Astrophysics Data System (ADS)

Macedo, Lucas Saran; Kawakubo, Fernando Shinji

2017-10-01

Agricultural production is one of the most important Brazilian economic activities accounting for about 21,5% of total Gross Domestic Product. In this scenario, the use of satellite images for estimating biophysical parameters along the phenological development of agricultural crops allows the conclusion about the sanity of planting and helps the projection on design production trends. The objective of this study is to analyze the temporal patterns and variation of six vegetion indexes obtained from the bands of Sentinel 2A satellite, associated with greenness (NDVI and ClRE), senescence (mARI and PSRI) and water content (DSWI and NDWI) to estimate maize production. The temporal pattern of the indices was analyzed in function of productivity data collected in-situ. The results obtained evidenced the importance of the SWIR and Red Edge ranges with Pearson correlation values of the temporal mean for NDWI 0.88 and 0.76 for CLRE.

Space-time analysis of snow cover change in the Romanian Carpathians (2001-2016)

NASA Astrophysics Data System (ADS)

Micu, Dana; Cosmin Sandric, Ionut

2017-04-01

Snow cover is recognized as an essential climate variable, highly sensitive to the ongoing climate warming, which plays an important role in regulating mountain ecosystems. Evidence from the existing weather stations located above 800 m over the last 50 years points out that the climate of the Romanian Carpathians is visibly changing, showing an ongoing and consistent warming process. Quantifying and attributing the changes in snow cover on various spatial and temporal scales have a great environmental and socio-economic importance for this mountain region. The study is revealing the inter-seasonal changes in the timing and distribution of snow cover across the Romanian Carpathians, by combining gridded snow data (CARPATCLIM dataset, 1961-2010) and remote sensing data (2001-2016) in specific space-time assessment at regional scale. The geostatistical approach applied in this study, based on a GIS hotspot analysis, takes advantage of all the dimensions in the datasets, in order to understand the space-time trends in this climate variable at monthly time-scale. The MODIS AQUA and TERRA images available from 2001 to 2016 have been processed using ArcGIS for Desktop and Python programming language. All the images were masked out with the Carpathians boundary. Only the pixels with snow have been retained for analysis. The regional trends in snow cover distribution and timing have been analysed using Space-Time cube with ArcGIS for Desktop, according with Esri documentation using the Mann-Kendall trend test on every location with data as an independent bin time-series test. The study aimed also to assess the location of emerging hotspots of snow cover change in Carpathians. These hotspots have been calculated using Getis-Ord Gi* statistic for each bin using Hot Spot Analysis implemented in ArcGIS for Desktop. On regional scale, snow cover appear highly sensitive to the decreasing trends in air temperatures and land surface temperatures, combined with the decrease in seasonal precipitation, especially at lower elevations in all the three divisions of the Romanian Carpathians (generally below 1,700-1,800 m). The space-time patterns of snow cover change are dominated by a significant decreasing trend of snow days and earlier spring snow melt. The key findings of this study provides robust indication of a decreasing snow trends across the Carpathian Mountain region and could provide valuable spatial and temporal snow information for other related research fields as well as for an effective environmental monitoring in the mountain ecosystems of the Carpathian region

Temporal trends in nitrate and selected pesticides in Mid-Atlantic ground water.

PubMed

Debrewer, Linda M; Ator, Scott W; Denver, Judith M

2008-01-01

Evaluating long-term temporal trends in regional ground-water quality is complicated by variable hydrogeologic conditions and typically slow flow, and such trends have rarely been directly measured. Ground-water samples were collected over near-decadal and annual intervals from unconfined aquifers in agricultural areas of the Mid-Atlantic region, including fractured carbonate rocks in the Great Valley, Potomac River Basin, and unconsolidated sediments on the Delmarva Peninsula. Concentrations of nitrate and selected pesticides and degradates were compared among sampling events and to apparent recharge dates. Observed temporal trends are related to changes in land use and chemical applications, and to hydrogeology and climate. Insignificant differences in nitrate concentrations in the Great Valley between 1993 and 2002 are consistent with relatively steady fertilizer application during respective recharge periods and are likely related to drought conditions in the later sampling period. Detecting trends in Great Valley ground water is complicated by long open boreholes characteristic of wells sampled in this setting which facilitate significant ground-water mixing. Decreasing atrazine and prometon concentrations, however, reflect reported changes in usage. On the Delmarva Peninsula between 1988 and 2001, median nitrate concentrations increased 2 mg per liter in aerobic ground water, reflecting increasing fertilizer applications. Correlations between selected pesticide compounds and apparent recharge date are similarly related to changing land use and chemical application. Observed trends in the two settings demonstrate the importance of considering hydrogeology and recharge date along with changing land and chemical uses when interpreting trends in regional ground-water quality.

Temporal trends of contaminants in Arctic char (Salvelinus alpinus) from a small lake, southwest Greenland during a warming climate.

PubMed

Rigét, Frank; Vorkamp, Katrin; Muir, Derek

2010-12-01

Hg and legacy POPs were analysed in muscle tissue of a landlocked Arctic char (Salvelinus alpinus) population from a small lake in southwest Greenland. Hg concentrations were available for six years and OC concentrations for five years during the period 1994 to 2008. For two years, stable isotope values of nitrogen (δ(15)N) were analysed in muscle tissue in order to infer trophic effects. Hg, Σ10-PCB, ΣDDT and trans-nonachlor concentrations (OC on wet weight basis) showed an increase with increasing fish length, which had to be accounted for when assessing temporal trends. δ(15)N values had a narrow range, and there was no indication of increasing δ(15)N values with char length confirming the sampled char did not vary in trophic morphs as often seen in Arctic lakes. Length-adjusted Hg concentrations showed a significantly increasing trend during the period 1994 to 2008, while Σ10-PCB, ΣDDT, ΣHCH and trans-nonachlor showed a significantly decreasing trend when expressed on wet weight, and decreasing but not significantly when expressed on lipid weight. The reason for this was that the lipid content of muscle showed a significantly decreasing trend with time. The sum of mean monthly air temperature during May to August measured at a nearby meteorological station showed an increasing trend during the study period, and changing temperature conditions probably influenced the temporal trend of especially Hg concentrations and the lipid content.

Statistical Analysis of Demographic and Temporal Differences in LANL's 2014 Voluntary Protection Program Survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Adam Christopher; Booth, Steven Richard

2015-08-20

Voluntary Protection Program (VPP) surveys were conducted in 2013 and 2014 to assess the degree to which workers at Los Alamos National Laboratory feel that their safety is valued by their management and peers. The goal of this analysis is to determine whether the difference between the VPP survey scores in 2013 and 2014 is significant, and to present the data in a way such that it can help identify either positive changes or potential opportunities for improvement. Data for several questions intended to identify the demographic groups of the respondent are included in both the 2013 and 2014 VPPmore » survey results. These can be used to identify any significant differences among groups of employees as well as to identify any temporal trends in these cohorts.« less

Estimating urban vegetation fraction across 25 cities in pan-Pacific using Landsat time series data

NASA Astrophysics Data System (ADS)

Lu, Yuhao; Coops, Nicholas C.; Hermosilla, Txomin

2017-04-01

Urbanization globally is consistently reshaping the natural landscape to accommodate the growing human population. Urban vegetation plays a key role in moderating environmental impacts caused by urbanization and is critically important for local economic, social and cultural development. The differing patterns of human population growth, varying urban structures and development stages, results in highly varied spatial and temporal vegetation patterns particularly in the pan-Pacific region which has some of the fastest urbanization rates globally. Yet spatially-explicit temporal information on the amount and change of urban vegetation is rarely documented particularly in less developed nations. Remote sensing offers an exceptional data source and a unique perspective to map urban vegetation and change due to its consistency and ubiquitous nature. In this research, we assess the vegetation fractions of 25 cities across 12 pan-Pacific countries using annual gap-free Landsat surface reflectance products acquired from 1984 to 2012, using sub-pixel, spectral unmixing approaches. Vegetation change trends were then analyzed using Mann-Kendall statistics and Theil-Sen slope estimators. Unmixing results successfully mapped urban vegetation for pixels located in urban parks, forested mountainous regions, as well as agricultural land (correlation coefficient ranging from 0.66 to 0.77). The greatest vegetation loss from 1984 to 2012 was found in Shanghai, Tianjin, and Dalian in China. In contrast, cities including Vancouver (Canada) and Seattle (USA) showed stable vegetation trends through time. Using temporal trend analysis, our results suggest that it is possible to reduce noise and outliers caused by phenological changes particularly in cropland using dense new Landsat time series approaches. We conclude that simple yet effective approaches of unmixing Landsat time series data for assessing spatial and temporal changes of urban vegetation at regional scales can provide critical information for urban planners and anthropogenic studies globally.

Frequency Analysis of Extreme Sub-Daily Precipitation under Stationary and Non-Stationary Conditions across Two Contrasting Hydroclimatic Environments

NASA Astrophysics Data System (ADS)

Demaria, E. M.; Goodrich, D. C.; Keefer, T.

2017-12-01

Observed sub-daily precipitation intensities from contrasting hydroclimatic environments in the USA are used to evaluate temporal trends and to develop Intensity-Duration Frequency (IDF) curves under stationary and nonstationary climatic conditions. Analyses are based on observations from two United States Department of Agriculture (USDA)-Agricultural Research Service (ARS) experimental watersheds located in a semi-arid and a temperate environment. We use an Annual Maximum Series (AMS) and a Partial Duration Series (PDS) approach to identify temporal trends in maximum intensities for durations ranging from 5- to 1440-minutes. A Bayesian approach with Monte Carlo techniques is used to incorporate the effect of non-stationary climatic assumptions in the IDF curves. The results show increasing trends in observed AMS sub-daily intensities in both watersheds whereas trends in the PDS observations are mostly positive in the semi-arid site and a mix of positive and negative in the temperate site. Stationary climate assumptions lead to much lower estimated sub-daily intensities than those under non-stationary assumptions with larger absolute differences found for shorter durations and smaller return periods. The risk of failure (R) of a hydraulic structure is increased for non-stationary effects over those of stationary effects, with absolute differences of 25% for a 100-year return period (T) and a project life (n) of 100 years. The study highlights the importance of considering non-stationarity, due to natural variability or to climate change, in storm design.

An Overview of OCTAV-UTLS (Observed Composition Trends and Variability in the UTLS), a SPARC Emerging Activity

NASA Astrophysics Data System (ADS)

Petropavlovskikh, I. V.; Manney, G. L.; Hoor, P. M.; Bourassa, A. E.; Braathen, G.; Chang, K. L.; Hegglin, M. I.; Kramarova, N. A.; Kunkel, D.; Lawrence, Z. D.; Leblanc, T.; Livesey, N. J.; Millan Valle, L. F.; Stiller, G. P.; Tegtmeier, S.; Thouret, V.; Voigt, C.; Walker, K. A.

2017-12-01

The distribution of tracers in the upper troposphere and lower stratosphere (UTLS) shows large spatial and temporal variability because of interactions of transport, chemical, and mixing processes near the tropopause, as well as variations in the location of the tropopause itself. This strongly affects quantitative estimates of the impact of radiatively active substances, including ozone and water vapour, on surface temperatures, and complicates diagnosis of dynamical processes such as stratosphere troposphere exchange (STE). The Stratosphere-troposphere Processes And their Role in Climate (SPARC) emerging activity OCTAV-UTLS (Observed Composition Trends and Variability in the UTLS) aims to reduce the uncertainties in trend estimates by accounting for these dynamically induced sources of variability. Achieving these goals by using existing UTLS trace gas observations from aircraft, ground-based, balloon and satellite platforms requires a consistent analysis of these different data with respect to the tropopause or the jets. As a central task for OCTAV-UTLS, we are developing and applying common metrics, calculated using the same reanalysis datasets, to compare UTLS data using geophysically-based coordinate systems including tropopause and upper tropospheric jet relative coordinates. In addition to assessing present day measurement capabilities, OCTAV-UTLS will assess gaps in current geographical / temporal sampling of the UTLS that limit our ability to determine atmospheric composition variability and trends. This talk will provide an overview of the OCTAV-UTLS activity and some examples of initial calculations of geophysically-based coordinates and comparisons of remapped data.

Contemporary Trends in Land Surface Phenologies from the Aral Basin Suggest Weather- or Irrigation-Driven Changes in GPP not Land Cover Change

NASA Astrophysics Data System (ADS)

Wright, C. K.; de Beurs, K.; Henebry, G. M.

2009-12-01

The transformation of the Aral Sea into the Aral Lakes is a startling example of anthropogenic environmental degradation. However, ongoing impacts of hydrologic modification and climatic change are occurring throughout the nearly 2 million km2 Aral Basin (AB), thus requiring synoptic, basin-wide monitoring of environmental trends. The MODIS 500m global land cover (LC) product is a potential source of such information in a data-sparse region like the AB. However, we find that it is particularly unstable in this arid/semi-arid region. For example, 25% of AB pixels change LC class between 2001 and 2005 versions of the global LC using the IGBP LC scheme. Here we present an alternate analysis of environmental trends in the AB using MODIS data at the same spatial resolution, but incorporating temporal information embedded within contemporary land surface phenologies (LSPs), in contrast to temporally delimited LC. NDVI time series from 2001-2008 were derived from 500m MODIS NBAR data (16-d composites every 8 d; MCD43A4). Focusing on the period from 1 March to 1 October, each pixel time series was comprised of 27 NDVI values per year (or 216 composites in total). Trend analysis using the nonparametric Seasonal Kendall test revealed a number of spatially coherent hotspots of highly significant (p<0.01) positive and negative trends in NDVI dynamics over the 2001-2008 interval. Relative to the 2001 and 2005 LC classifications, positive trends tended to coincide with the following transitions between IGBP classes: open shrub → closed shrub; grassland → {open shrub, cropland}; {open shrub, cropland/natural vegetation mix} → cropland. These findings suggest that apparent LC change events might be false-positives caused by weather-driven increases in GPP. In turn, negative trends were largely coincident with putative LC change to grassland from mostly woody classes: {closed shrub, open shrub, woody savanna, savanna, snow/ice, barren} → grassland. Here, potential false-positives may reflect effects of regional drought on woody classes, declining mountain snowpack, or original misclassification of grassland as barren, i.e., we would expect declining NDVI in drought-affected grassland, with limited sensitivity to NDVI trends in the barren class. In the intensively irrigated subregion of Karakalpakstan, the MODIS LC product indicates an elevated rate of change from natural vegetation to cropland and vice versa. These transitions tend to coincide with highly significant (p<0.01) negative or positive NDVI trends. However, visual inspection of 2001 and 2005 Landsat imagery from Karakalpakstan did not indicate extensive LC change. Here we interpret apparent false-positives in the global LC product as arising from localized changes in irrigation or cropping practices. Overall, this work demonstrates the utility of temporally dense LSPs for large-area monitoring of environmental change, as opposed to occasional LC classifications which, in arid regions like the AB, may exhibit instability and sensitivity with respect to a region’s normal range of interannual spectral variability.

Historical trend in river ice thickness and coherence in hydroclimatological trends in Maine

USGS Publications Warehouse

Huntington, T.G.; Hodgkins, G.A.; Dudley, R.W.

2003-01-01

We analyzed long-term records of ice thickness on the Piscataquis River in central Maine and air temperature in Maine to determine whether there were temporal trends that were associated with climate warming. The trend in ice thickness was compared and correlated with regional time series of winter air temperature, heating degree days (HDD), date of river ice-out, seasonal center-of-volume date (SCVD) (date on which half of the stream runoff volume during the period 1 Jan. to 31 May has occurred), water temperature, and lake ice-out date. All of these variables except lake ice-out date showed significant temporal trends during the 20th century. Average ice thickness around 28 February decreased by about 23 cm from 1912 to 2001. Over the period 1900 to 1999, winter air temperature increased by 1.7??C and HDD decreased by about 7.5%. Final ice-out date on the Piscataquis River occurred earlier (advanced), by 0.21 days yr-1 over the period 1931 to 2002, and the SCVD advanced by 0.11 days yr-1 over the period 1903 to 2001. Ice thickness was significantly correlated (P-value < 0.01) with winter air temperature, HDD, river ice-out, and SCVD. These systematic temporal trends in multiple hydrologic indicator variables indicate a coherent response to climate forcing.

Canadian population trends in leisure-time physical activity levels, 1981-1998.

PubMed

Bruce, Marny J; Katzmarzyk, Peter T

2002-12-01

Age, sex, geographic and temporal trends in leisure-time physical activity levels were examined using data from five national surveys conducted between 1981 and 1998. Physical activity energy expenditure (AEE) was higher among men compared to women, and in younger versus older adults. AEE increased from Eastern to Western Canada, with a significant temporal trend of increasing AEE. The prevalence of physical inactivity (expending <12.6 kJ x kg(-1) x day(-1) has decreased; however, it remains high (women: 77%; men: 74%). The high prevalence of physical inactivity emphasizes the importance of population-level physical activity surveillance and interventions.

PBDEs and PCBs in the liver of the St Lawrence Estuary beluga (Delphinapterus leucas): a comparison of levels and temporal trends with the blubber.

PubMed

Raach, Meriem; Lebeuf, Michel; Pelletier, Emilien

2011-03-01

Due to their lipophilic properties, persistent organic pollutants (POPs) are commonly assessed using the blubber of marine mammals. However, these chemicals are also accumulating in other tissues including the liver. Some pollutants, namely perfluorinated alkyl acids, are found predominately in the liver and blood of marine mammals, and thus monitored in those tissues. This raises the question whether any tissue would represent an identical trend of POPs in the SLE beluga. The current study reports the first temporal trends of PBDEs and PCBs in the liver of 65 SLE belugas. Neither ∑₇PBDEs nor major individual PBDE-homolog group concentrations showed significant trends between 1993 and 2007. Also, ∑₃₂PCBs did not change over years, although, tetra-, penta- and hepta-PCB decreased by 7.1, 6.8 and 8.5%, respectively, in males, whereas tetra-, penta- and octa-PCBs declined by 11, 12 and 12.9%, respectively, in females. In order to compare the distribution of POPs between liver and blubber, a lipid normalised concentration ratio R (blubber/liver) for PBDEs and PCBs was calculated for each individual beluga. For all PBDE and several PCB homolog groups, mean R values were not statistically different from unity indicating that the partitioning of these POPs is governed by the tissue lipid-content. Temporal trends of R ratios of PBDEs and PCBs were also examined. There were generally no significant temporal trends except for PBDEs in males where R increased in average by 12.7 ± 2.9% yearly. The stratification of the blubber into a metabolically active (inner) and less active layers (outer blubber) may result in a slower response time of the blubber (full depth) than the liver to the recent change of contamination in the environment and explain the time trend differences between both tissues. This study suggests that the liver is more representative of recent exposure to lipophilic contaminants.

Use of environmental tracers to evaluate ground-water age and water-quality trends in a buried-valley aquifer, Dayton area, southwestern, Ohio

USGS Publications Warehouse

Rowe, Gary L.; Shapiro, Stephanie Dunkle; Schlosser, Peter

1999-01-01

Chlorofluorocarbons (CFC method) and tritium and helium isotopes (3H-3He method) were used as environmental tracers to estimate ground-water age in conjunction with efforts to develop a regional ground-water flow model of the buried-valley aquifer in the Dayton area, southwestern Ohio. This report describes results of CFC and water-quality sampling, summarizes relevant aspects of previously published work, and describes the use of 3H-3He ages to characterize temporal trends in ground-water quality of the buried-valley aquifer near Dayton, Ohio. Results of CFC sampling indicate that approximately 25 percent of the 137 sampled wells were contaminated with excess CFC's that rendered the ground water unsuitable for age dating. Evaluation of CFC ages obtained for the remaining samples indicated that the CFC compounds used for dating were being affected by microbial degradation. The degradation occurred under anoxic conditions that are found in most parts of the buried-valley aquifer. As a result, ground-water ages derived by the CFC method were too old and were inconsistent with measured tritium concentrations and independently derived 3H-3He ages. Limited data indicate that dissolved methane may play an important role in the degradation of the CFC's. In contrast, the 3H-3He technique was found to yield ground-water ages that were chemically and hydrologically reasonable. Ground-water ages derived by the 3H-3He technique were compared to values for selected water- quality characteristics to evaluate temporal trends in ground-water quality in the buried- valley aquifer. Distinct temporal trends were not identified for pH, alkalinity, or calcium and magnesium because of rapid equilibration of ground-water with calcite and dolomite in aquifer sediments. Temporal trends in which the amount of scatter and the number of outlier concentrations increased as ground-water age decreased were noted for sodium, potassium, boron, bromide, chloride, ammonia, nitrate, phosphate, sulfate, and organic carbon. Elevated concentrations of these constituents in shallow ground water are probably related to human activities. Temporal trends in which concentrations declined as ground-water age increased may reflect natural processes that reduce constituent concentrations to low levels. For example, the absence of nitrate detections in ground water recharged before 1980 may indicate natural removal of nitrate by bacterially mediated denitrification. Temporal trends observed for dissolved oxygen, iron, nitrate and silica indicate that these constituents may help identify recently (post-1990) recharged ground water.

Long-term trends in the structure of eastern Adriatic littoral fish assemblages: Consequences for fisheries management

NASA Astrophysics Data System (ADS)

Stagličić, N.; Matić-Skoko, S.; Pallaoro, A.; Grgičević, R.; Kraljević, M.; Tutman, P.; Dragičević, B.; Dulčić, J.

2011-09-01

Long-term interannual changes in abundance, biomass, diversity and structure of littoral fish assemblages were examined between 1993 and 2009 by experimental trammel net fishing up to six times per year, within the warm period - May to September, at multiple areas along the eastern Adriatic coast with the aim of testing for the consistency of patterns of change across a large spatial scale (˜600 km). The results revealed spatially consistent increasing trends of total fish abundance and biomass growing at an average rate of 15 and 14% per year, respectively. Of the diversity indices analysed, the same pattern of variability was observed for Shannon diversity, while Pielou evenness and average taxonomic distinctness measures Δ ∗ and Δ + showed spatial variability with no obvious temporal trends. Multivariate fish assemblage structure underwent a directional change displaying a similar pattern through time for all the areas. The structural change in fish assemblages generally involved most of the species present in trammel net catches. A large pool of fish species responsible for producing the temporal pattern of assemblage change was relatively different in each of the areas reflecting a large geographic range covered by the study. An analysis of 4 fish species ( Symphodus tinca, Pagellus erythrinus, Mullus surmuletus, Scorpaena porcus) common to each of the study areas as the ones driving the temporal change indicated that there were clear increasing trends of their mean catches across the years at all the study areas. A common pattern among time trajectories across the spatial scale studied implies that the factor affecting the littoral fish assemblages is not localised but regional in nature. As an underlying factor having the potential to induce such widespread and consistent improvements in littoral fish assemblages, a more restrictive artisanal fishery management that has progressively been put in place during the study period, is suggested and discussed.

Dental occlusion analysis in the Mesolithic-Neolithic Age, Bronze Age, and Roman to Medieval times in Serbia: Tooth size comparison in skeletal samples.

PubMed

Pajević, Tina; Glišić, Branislav

2017-05-01

Anthropological studies have reported that tooth size decreases in the context of diet changes. Some investigations have found a reverse trend in tooth size from the prehistoric to the modern times. The aims of this study were to analyze tooth size in skeletal samples from Mesolithic-Neolithic Age, Bronze Age, and Roman to Medieval times to determine sex differences and establish a temporal trend in tooth size in the aforementioned periods. Well-preserved permanent teeth were included in the investigation. The mesiodistal (MD) diameter of all teeth and buccolingual (BL) diameter of the molars were measured. Effects of sex and site were tested by one-way ANOVA, and the combined effect of these factors was analyzed by UNIANOVA. Sexual dimorphism was present in the BL diameters of all molars and MD diameters of the upper first and the lower third molar. The lower canine was the most dimorphic tooth in the anterior region. The MD diameter of most teeth showed no significant difference between the groups, (sample from: Mesolithic-Neolithic Age-group 1; Bronze Age-group 2; Roman times-group 3; Medieval times-group 4), whereas the BL diameters of the upper second and the lower first molar were the largest in the first group. Multiple comparisons revealed a decrease in the BL diameter of the upper second and the lower first molar from the first to the later groups. Lower canine MD diameter exhibited an increase in the fourth group compared to the second group. On the basis of the MD diameter, a temporal trend could not be observed for most of the teeth. The lower canine exhibited an increase in the MD diameter from the prehistoric to the Medieval times. Changes of BL diameter were more homogeneous, suggesting that the temporal trend of molar size decreased from the Mesolithic-Neolithic to Medieval times in Serbia. Copyright © 2017. Published by Elsevier Ltd.

Biomonitoring of metals under the water framework directive: detecting temporal trends and abrupt changes, in relation to the removal of pollution sources.

PubMed

Solaun, O; Rodríguez, J G; Borja, A; González, M; Saiz-Salinas, J I

2013-02-15

Temporal trends in metal concentrations, i.e. Ag, Cd, Cu, Cr, Hg, Ni, Pb and Zn, measured in soft tissues of Mytilus galloprovincialis mussels and Crassostrea gigas oysters collected from estuarine waters within the Basque Country (Bay of Biscay), have been investigated to determine if actions undertaken have improved the environmental quality of rivers and estuaries. Data compiled between 1990 and 2010 have been analysed statistically, applying the Mann-Kendall and the Mann-Whitney-Wilcoxon tests. Moreover, in those cases with significant trends, the Kolmogorov-Zurbenko Adaptive (KZA) filter was applied to detect abrupt changes. Results showed significant decreasing trends for some metals, i.e. Ni, Cu, Pb and Zn, and differences between medians. Trend lines showed abrupt changes occurring between 1998 and 2002. Therefore, observed downward trends were related to increased wastewater treatment and diversions of discharges to ocean, implemented mainly during 2000-2002. Copyright © 2012 Elsevier Ltd. All rights reserved.

Revisiting AVHRR Tropospheric Aerosol Trends Using Principal Component Analysis

NASA Technical Reports Server (NTRS)

Li, Jing; Carlson, Barbara E.; Lacis, Andrew A.

2014-01-01

The advanced very high resolution radiometer (AVHRR) satellite instruments provide a nearly 25 year continuous record of global aerosol properties over the ocean. It offers valuable insights into the long-term change in global aerosol loading. However, the AVHRR data record is heavily influenced by two volcanic eruptions, El Chichon on March 1982 and Mount Pinatubo on June 1991. The gradual decay of volcanic aerosols may last years after the eruption, which potentially masks the estimation of aerosol trends in the lower troposphere, especially those of anthropogenic origin. In this study, we show that a principal component analysis approach effectively captures the bulk of the spatial and temporal variability of volcanic aerosols into a single mode. The spatial pattern and time series of this mode provide a good match to the global distribution and decay of volcanic aerosols. We further reconstruct the data set by removing the volcanic aerosol component and reestimate the global and regional aerosol trends. Globally, the reconstructed data set reveals an increase of aerosol optical depth from 1985 to 1990 and decreasing trend from 1994 to 2006. Regionally, in the 1980s, positive trends are observed over the North Atlantic and North Arabian Sea, while negative tendencies are present off the West African coast and North Pacific. During the 1994 to 2006 period, the Gulf of Mexico, North Atlantic close to Europe, and North Africa exhibit negative trends, while the coastal regions of East and South Asia, the Sahel region, and South America show positive trends.

Detecting trend on ecological river status - how to deal with short incomplete bioindicator time series? Methodological and operational issues

NASA Astrophysics Data System (ADS)

Cernesson, Flavie; Tournoud, Marie-George; Lalande, Nathalie

2018-06-01

Among the various parameters monitored in river monitoring networks, bioindicators provide very informative data. Analysing time variations in bioindicator data is tricky for water managers because the data sets are often short, irregular, and non-normally distributed. It is then a challenging methodological issue for scientists, as it is in Saône basin (30 000 km2, France) where, between 1998 and 2010, among 812 IBGN (French macroinvertebrate bioindicator) monitoring stations, only 71 time series have got more than 10 data values and were studied here. Combining various analytical tools (three parametric and non-parametric statistical tests plus a graphical analysis), 45 IBGN time series were classified as stationary and 26 as non-stationary (only one of which showing a degradation). Series from sampling stations located within the same hydroecoregion showed similar trends, while river size classes seemed to be non-significant to explain temporal trends. So, from a methodological point of view, combining statistical tests and graphical analysis is a relevant option when striving to improve trend detection. Moreover, it was possible to propose a way to summarise series in order to analyse links between ecological river quality indicators and land use stressors.

In-depth analysis of accidental oil spills from tankers in the context of global spill trends from all sources.

PubMed

Burgherr, Peter

2007-02-09

This study gives a global overview of accidental oil spills from all sources (> or =700t) for the period 1970-2004, followed by a detailed examination of trends in accidental tanker spills. The present analysis of the number and volume of tanker spills includes temporal and spatial spill trends, aspects of spill size distribution as well as trends of key factors (i.e., flag state, hull type, tanker age, accident cause and sensitivity of location). Results show that the total number and volume of tanker spills have significantly decreased since the 1970s, which is in contrast to increases in maritime transport of oil and to popular perceptions following recent catastrophic events. However, many spills still occur in ecologically sensitive locations because the major maritime transport routes often cross the boundaries of the Large Marine Ecosystems, but the substantially lower total spill volume is an important contribution to potentially reduce overall ecosystem impacts. In summary, the improvements achieved in the past decades have been the result of a set of initiatives and regulations implemented by governments, international organizations and the shipping industry.

Macroeconomic effects on mortality revealed by panel analysis with nonlinear trends.

PubMed

Ionides, Edward L; Wang, Zhen; Tapia Granados, José A

2013-10-03

Many investigations have used panel methods to study the relationships between fluctuations in economic activity and mortality. A broad consensus has emerged on the overall procyclical nature of mortality: perhaps counter-intuitively, mortality typically rises above its trend during expansions. This consensus has been tarnished by inconsistent reports on the specific age groups and mortality causes involved. We show that these inconsistencies result, in part, from the trend specifications used in previous panel models. Standard econometric panel analysis involves fitting regression models using ordinary least squares, employing standard errors which are robust to temporal autocorrelation. The model specifications include a fixed effect, and possibly a linear trend, for each time series in the panel. We propose alternative methodology based on nonlinear detrending. Applying our methodology on data for the 50 US states from 1980 to 2006, we obtain more precise and consistent results than previous studies. We find procyclical mortality in all age groups. We find clear procyclical mortality due to respiratory disease and traffic injuries. Predominantly procyclical cardiovascular disease mortality and countercyclical suicide are subject to substantial state-to-state variation. Neither cancer nor homicide have significant macroeconomic association.

Macroeconomic effects on mortality revealed by panel analysis with nonlinear trends

PubMed Central

Ionides, Edward L.; Wang, Zhen; Tapia Granados, José A.

2013-01-01

Many investigations have used panel methods to study the relationships between fluctuations in economic activity and mortality. A broad consensus has emerged on the overall procyclical nature of mortality: perhaps counter-intuitively, mortality typically rises above its trend during expansions. This consensus has been tarnished by inconsistent reports on the specific age groups and mortality causes involved. We show that these inconsistencies result, in part, from the trend specifications used in previous panel models. Standard econometric panel analysis involves fitting regression models using ordinary least squares, employing standard errors which are robust to temporal autocorrelation. The model specifications include a fixed effect, and possibly a linear trend, for each time series in the panel. We propose alternative methodology based on nonlinear detrending. Applying our methodology on data for the 50 US states from 1980 to 2006, we obtain more precise and consistent results than previous studies. We find procyclical mortality in all age groups. We find clear procyclical mortality due to respiratory disease and traffic injuries. Predominantly procyclical cardiovascular disease mortality and countercyclical suicide are subject to substantial state-to-state variation. Neither cancer nor homicide have significant macroeconomic association. PMID:24587843

Lead and Antimony Speciation in Shooting Range Soils: Molecular Scale Analysis, Temporal Trends and Mobility

DTIC Science & Technology

2017-11-20

35 Figure 25. Effects of saturation time on Pb concentrations as a function of soil type and column...36 Figure 26. Effects of saturation time on Sb concentrations as a function of soil type and column set (a...representation of the oxygen -terminated full layer termination surface of hematite ( ) (second octahedral layer and those beneath are not shown for clarity) ; (D

Trends in atmospheric evaporative demand in Great Britain using high-resolution meteorological data

NASA Astrophysics Data System (ADS)

Robinson, Emma L.; Blyth, Eleanor M.; Clark, Douglas B.; Finch, Jon; Rudd, Alison C.

2017-02-01

Observations of climate are often available on very different spatial scales from observations of the natural environments and resources that are affected by climate change. In order to help bridge the gap between these scales using modelling, a new dataset of daily meteorological variables was created at 1 km resolution over Great Britain for the years 1961-2012, by interpolating coarser resolution climate data and including the effects of local topography. These variables were used to calculate atmospheric evaporative demand (AED) at the same spatial and temporal resolution. Two functions that represent AED were chosen: one is a standard form of potential evapotranspiration (PET) and the other is a derived PET measure used by hydrologists that includes the effect of water intercepted by the canopy (PETI). Temporal trends in these functions were calculated, with PET found to be increasing in all regions, and at an overall rate of 0.021 ± 0.021 mm day-1 decade-1 in Great Britain. PETI was found to be increasing at a rate of 0.019 ± 0.020 mm day-1 decade-1 in Great Britain, but this was not statistically significant. However, there was a trend in PETI in England of 0.023 ± 0.023 mm day-1 decade-1. The trends were found to vary by season, with spring PET increasing by 0.043 ± 0.019 mm day-1 decade-1 (0.038 ± 0.018 mm day-1 decade-1 when the interception correction is included) in Great Britain, while there is no statistically significant trend in other seasons. The trends were attributed analytically to trends in the climate variables; the overall positive trend was predominantly driven by rising air temperature, although rising specific humidity had a negative effect on the trend. Recasting the analysis in terms of relative humidity revealed that the overall effect is that falling relative humidity causes the PET to rise. Increasing downward short- and longwave radiation made an overall positive contribution to the PET trend, while decreasing wind speed made a negative contribution to the trend in PET. The trend in spring PET was particularly strong due to a strong decrease in relative humidity and increase in downward shortwave radiation in the spring.

Level and temporal trend of perfluoroalkyl acids in Greenlandic Inuit

PubMed Central

Long, Manhai; Bossi, Rossana; Bonefeld-Jørgensen, Eva C.

2012-01-01

Objectives Perfluoroalkyl acids (PFAAs) have been detected in human blood, breast milk and umbilical cord blood across the globe. PFAAs do accumulate in the marine food chain in Arctic regions. In Greenland, increasing PFAA concentrations were observed during 1982–2006 in ringed seals and polar bears. However, until now, no data have been reported for PFAAs in Greenlandic Inuit. This study assesses the level and temporal trend of serum PFAAs in Greenlandic Inuit. Study design Cross-section and temporal time trend survey. Methods Serum PFAA levels were determined in 284 Inuit from different Greenlandic districts using liquid chromatography-tandem mass spectrometry with electrospray ionization. The temporal time trend of serum PFAAs in Nuuk Inuit during 1998–2005 and the correlation between serum PFAAs and legacy persistent organic pollutants (POPs) were explored. Results Serum PFAA levels were higher in Nuuk Inuit than in non-Nuuk Inuit. Within the same district, higher PFAA levels were observed for males. An age-dependent, increasing trend of serum PFAA levels in the period from 1998–2005 was observed for Nuuk Inuit. For the pooled gender data, no significant association between PFAAs and legacy POPs was observed for Nuuk Inuit while for non-Nuuk Inuit this correlation was significant. No correlation between PFAAs and legacy POPs was found for male Inuit, whereas significant correlation was observed both for pooled female Inuit and for non-Nuuk Inuit females. Conclusions We suggest that sources other than seafood intake might contribute to the observed higher PFAA levels in Nuuk Inuit compared to the pooled non-Nuuk Inuit.1 PMID:22456049

Mapping permafrost change hot-spots with Landsat time-series

NASA Astrophysics Data System (ADS)

Grosse, G.; Nitze, I.

2016-12-01

Recent and projected future climate warming strongly affects permafrost stability over large parts of the terrestrial Arctic with local, regional and global scale consequences. The monitoring and quantification of permafrost and associated land surface changes in these areas is crucial for the analysis of hydrological and biogeochemical cycles as well as vegetation and ecosystem dynamics. However, detailed knowledge of the spatial distribution and the temporal dynamics of these processes is scarce and likely key locations of permafrost landscape dynamics may remain unnoticed. As part of the ERC funded PETA-CARB and ESA GlobPermafrost projects, we developed an automated processing chain based on data from the entire Landsat archive (excluding MSS) for the detection of permafrost change related processes and hotspots. The automated method enables us to analyze thousands of Landsat scenes, which allows for a multi-scaled spatio-temporal analysis at 30 meter spatial resolution. All necessary processing steps are carried out automatically with minimal user interaction, including data extraction, masking, reprojection, subsetting, data stacking, and calculation of multi-spectral indices. These indices, e.g. Landsat Tasseled Cap and NDVI among others, are used as proxies for land surface conditions, such as vegetation status, moisture or albedo. Finally, a robust trend analysis is applied to each multi-spectral index and each pixel over the entire observation period of up to 30 years from 1985 to 2015, depending on data availability. Large transects of around 2 million km² across different permafrost types in Siberia and North America have been processed. Permafrost related or influencing landscape dynamics were detected within the trend analysis, including thermokarst lake dynamics, fires, thaw slumps, and coastal dynamics. The produced datasets will be distributed to the community as part of the ERC PETA-CARB and ESA GlobPermafrost projects. Users are encouraged to provide feedback and ground truth data for a continuous improvement of our methodology and datasets, which will lead to a better understanding of the spatial and temporal distribution of changes within the vulnerable permafrost zone.

Trends in chlorinated hydrocarbon levels in Hudson River basin sediments.

PubMed Central

Bopp, R F; Chillrud, S N; Shuster, E L; Simpson, H J; Estabrooks, F D

1998-01-01

Analysis of sections from dated sediment cores were used to establish geographic distributions and temporal trends of chlorinated hydrocarbon contaminant levels in sediments from natural waters of the Hudson River basin. Radiometric dating was based primarily on the depth distribution of 137(Cs) in the cores and on the occurrence of detectable levels of 7(Be) in surface sediment samples. Eighteen sampling sites included several along the main stem of the Hudson, its major tributaries, and components of the New York/New Jersey (NY/NJ) harbor complex. Drinking-water reservoirs were sampled to place upper limits on atmospheric inputs. Core sections were analyzed for polychlorinated biphenyls (PCBs), 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT)-derived compounds, chlordane, and dioxins. Sediment concentrations of most contaminants at most sites have decreased significantly since the mid-1960s. The data provide a basinwide perspective on major point-source inputs of PCBs to the upper Hudson River and of 2,3,7,8-tetrachlorodibenzo-p-dioxin and DDT to the lower Passaic River. Evidence was found for significant but poorly characterized sources of PCBs and chlordane to the western NY/NJ harbor, and of highly chlorinated dioxins to the upstream sites on the main stem of the Hudson. The results indicate that analysis of dated sediment samples is a most effective and efficient monitoring tool for the study of large-scale geographic and temporal trends in levels of particle-associated contaminants. Images Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:9703496

Linking plant functional trait plasticity and the large increase in forest water use efficiency

NASA Astrophysics Data System (ADS)

Mastrotheodoros, Theodoros; Pappas, Christoforos; Molnar, Peter; Burlando, Paolo; Keenan, Trevor F.; Gentine, Pierre; Gough, Christopher M.; Fatichi, Simone

2017-09-01

Elevated atmospheric CO2 concentrations are expected to enhance photosynthesis and reduce stomatal conductance, thus increasing plant water use efficiency. A recent study based on eddy covariance flux observations from Northern Hemisphere forests showed a large increase in inherent water use efficiency (IWUE). Here we used an updated version of the same data set and robust uncertainty quantification to revisit these contemporary IWUE trends. We tested the hypothesis that the observed IWUE increase could be attributed to interannual trends in plant functional traits, potentially triggered by environmental change. We found that IWUE increased by 1.3% yr-1, which is less than previously reported but still larger than theoretical expectations. Numerical simulations with the Tethys-Chloris ecosystem model using temporally static plant functional traits cannot explain this increase. Simulations with plant functional trait plasticity, i.e., temporal changes in model parameters such as specific leaf area and maximum Rubisco capacity, match the observed trends in IWUE. Our results show that trends in plant functional traits, equal to 1.0% yr-1, can explain the observed IWUE trends. Thus, at decadal or longer time scales, trait plasticity could potentially influence forest water, carbon, and energy fluxes with profound implications for both the monitoring of temporal changes in plant functional traits and their representation in Earth system models.

Spatial and temporal patterns in preterm birth in the United States.

PubMed

Byrnes, John; Mahoney, Richard; Quaintance, Cele; Gould, Jeffrey B; Carmichael, Suzan; Shaw, Gary M; Showen, Amy; Phibbs, Ciaran; Stevenson, David K; Wise, Paul H

2015-06-01

Despite years of research, the etiologies of preterm birth remain unclear. In order to help generate new research hypotheses, this study explored spatial and temporal patterns of preterm birth in a large, total-population dataset. Data on 145 million US births in 3,000 counties from the Natality Files of the National Center for Health Statistics for 1971-2011 were examined. State trends in early (<34 wk) and late (34-36 wk) preterm birth rates were compared. K-means cluster analyses were conducted to identify gestational age distribution patterns for all US counties over time. A weak association was observed between state trends in <34 wk birth rates and the initial absolute <34 wk birth rate. Significant associations were observed between trends in <34 wk and 34-36 wk birth rates and between white and African American <34 wk births. Periodicity was observed in county-level trends in <34 wk birth rates. Cluster analyses identified periods of significant heterogeneity and homogeneity in gestational age distributional trends for US counties. The observed geographic and temporal patterns suggest periodicity and complex, shared influences among preterm birth rates in the United States. These patterns could provide insight into promising hypotheses for further research.

Temporal trends of mercury concentrations in Wisconsin walleye (Sander vitreus), 1982-2005.

PubMed

Rasmussen, Paul W; Schrank, Candy S; Campfield, Patrick A

2007-11-01

The Wisconsin Department of Natural Resources has monitored mercury (Hg) in several species of fish since the early 1970s primarily for fish consumption advisory purposes. We selected skin-on fillets of walleye (Sander vitreus) from inland lakes collected over the years 1982-2005 to assess temporal trends of Hg concentrations. While individual lakes are of interest, sample sizes, and unbalanced collections across fish lengths, seasons, or years prevent estimates of temporal trends of walleye Hg concentrations within most lakes. We evaluated temporal trends over all lakes using mixed effects models (3,024 records from 421 lakes). Relationships between Hg concentrations and a suite of lake chemistry, morphometry, and other variables were also explored. Hg concentrations generally increased with walleye length but the relationship varied among lakes. The best-fitting mixed effects models suggested that the overall rate of change in walleye Hg across all lakes in the dataset varied with latitude. Hg in walleye decreased 0.5% per year in northern lakes, increased 0.8% in southern lakes, and remained constant in middle latitude lakes over the period of 1982-2005. Season of collection was also an important predictor variable. Hg concentrations were highest in walleye captured in the spring and lowest in the fall. Other variables such as gender, lake area, and total alkalinity were also important predictors.

Spatial and temporal analysis of drought variability at several time scales in Syria during 1961-2012

NASA Astrophysics Data System (ADS)

Mathbout, Shifa; Lopez-Bustins, Joan A.; Martin-Vide, Javier; Bech, Joan; Rodrigo, Fernando S.

2018-02-01

This paper analyses the observed spatiotemporal characteristics of drought phenomenon in Syria using the Standardised Precipitation Index (SPI) and the Standardised Precipitation Evapotranspiration Index (SPEI). Temporal variability of drought is calculated for various time scales (3, 6, 9, 12, and 24 months) for 20 weather stations over the 1961-2012 period. The spatial patterns of drought were identified by applying a Principal Component Analysis (PCA) to the SPI and SPEI values at different time scales. The results revealed three heterogeneous and spatially well-defined regions with different temporal evolution of droughts: 1) Northeastern (inland desert); 2) Southern (mountainous landscape); 3) Northwestern (Mediterranean coast). The evolutionary characteristics of drought during 1961-2012 were analysed including spatial and temporal variability of SPI and SPEI, the frequency distribution, and the drought duration. The results of the non-parametric Mann-Kendall test applied to the SPI and SPEI series indicate prevailing significant negative trends (drought) at all stations. Both drought indices have been correlated both on spatial and temporal scales and they are highly comparable, especially, over a 12 and 24 month accumulation period. We concluded that the temporal and spatial characteristics of the SPI and SPEI can be used for developing a drought intensity - areal extent - and frequency curve that assesses the variability of regional droughts in Syria. The analysis of both indices suggests that all three regions had a severe drought in the 1990s, which had never been observed before in the country. Furthermore, the 2007-2010 drought was the driest period in the instrumental record, happening just before the onset of the recent conflict in Syria.

Spatio-temporal examination of precipitation isotopes from the North American monsoon in Arizona, New Mexico, and Utah from 2014 to 2017

NASA Astrophysics Data System (ADS)

Tulley-Cordova, C. L.; Bowen, G. J.

2017-12-01

A significant summertime feature of climate in the southwestern United States (US) is the North American monsoon (NAM), also known as the Mexican monsoon, Arizona monsoon, and the southwestern United States monsoon. NAM is a crucial contributor to total annual precipitation in the Four Corners region of the US. Modern investigation of NAM in this region using stable isotopes has been poorly studied. This study characterizes the spatio-temporal changes of NAM based on stable isotopic results from 40 sites, located within the boundaries of the Navajo Nation, in Arizona, New Mexico, and Utah from 2014 to 2017. Sample collections were collected monthly at each site from May to October. Examination of temporal trends of precipitation revealed strong monthly and interannual changes; spatial analysis showed weak large-scale relationships across the study area. Analysis of stable isotopes in precipitation, surface, ground, and spring waters can be used to interpret the isotopic differences in the modern hydro-climate of the Navajo Nation and Colorado Plateau to help predict future hydro-climate changes and its implications on future water resources.

Trends in surgery for upper urinary tract calculi in the USA using the Nationwide Inpatient Sample: 1999-2009.

PubMed

Ghani, Khurshid R; Sammon, Jesse D; Karakiewicz, Pierre I; Sun, Maxine; Bhojani, Naeem; Sukumar, Shyam; Peabody, James O; Menon, Mani; Trinh, Quoc-Dien

2013-07-01

To determine trends in demographics and treatment for inpatient upper urinary tract calculi in the USA using a population-based cohort. All patients with a primary or secondary diagnosis of kidney or ureteric calculus between 1999 and 2009 in the US Nationwide Inpatient Sample were extracted and weighted. Temporal trend analyses were used to determine trends in gender, race and age presentation, as well as utilization rates of interventions. Temporal trends were quantified using the estimated annual percent change (EAPC) using least squares linear regression analysis. Overall, 2 109 455 patients were hospitalized with upper urinary tract calculi over the 11-year period. The majority of admissions were for ureteric calculi (63.4%). Admissions for renal calculus increased by 12.1% during the study period (EAPC + 0.92%, P = 0.039, 95% CI: 0.17-1.66), whilst discharges for ureteric calculus remained stable. A significant increase (25.4%) in hospitalizations for women was found (EAPC + 2.21%, P < 0.001, 95% CI: 1.40-3.03); by 2006, more women than men were admitted to hospital (95 953 vs. 94 556, respectively). There were significant increases in hospitalization for black, Hispanic and older patients. Significant changes in the use of all studied interventions were found except for ureteroscopy, extracorporeal shockwave lithotripsy and nephrectomy. In this nationally representative sample of inpatient discharges, significant increases were found in admissions for renal compared with ureteric calculi, and for black, Hispanic and older patients. With regard to surgical intervention, the largest increase was found in the use of procedures for kidney calculi. Women now comprise the majority in the inpatient management of stone disease. © 2013 BJU International.

Temporal trends of in-hospital complications associated with catheter ablation of atrial fibrillation in the United States: An update from Nationwide Inpatient Sample database (2011-2014).

PubMed

Tripathi, Byomesh; Arora, Shilpkumar; Kumar, Varun; Abdelrahman, Mohamed; Lahewala, Sopan; Dave, Mihir; Shah, Mahek; Tan, Bryan; Savani, Sejal; Badheka, Apurva; Gopalan, Radha; Shantha, Ghanshyam Palamaner Subash; Viles-Gonzalez, Juan; Deshmukh, Abhishek

2018-05-01

Catheter ablation is widely accepted intervention for atrial fibrillation (AF) refractory to antiarrhythmic drugs, but limited data are available regarding contemporary trends in major complications and in-hospital mortality due to the procedure. This study was aimed at exploring the temporal trends of in-hospital mortality, major complications, and impact of hospital volume on frequency of AF ablation-related outcomes. The Nationwide Inpatient Sample database was utilized to identify the AF patients treated with catheter ablation. In-hospital death and common complications including vascular access complications, cardiac perforation and/or tamponade, pneumothorax, stroke, and transient ischemic attack, were identified using International Classification of Disease (ICD-9-CM) codes. In-hospital mortality rate of 0.15% and overall complication rate of 5.46% were noted among AF ablation recipients (n = 50,969). Significant increase in complications during study period (relative increase 56.37%, P-trend < 0.001) was observed. Cardiac (2.65%), vascular (1.33%), and neurological (1.05%) complications were most common. On multivariate analysis (odds ratio [OR]; 95% confidence interval [95% CI]; P value), significant predictors of complications were female sex (OR = 1.40; CI = 1.17-1.68; P value < 0.001), high burden of comorbidity as indicated by Charlson Comorbidity Index ≥2 (OR = 2.84; CI = 2.29-3.52; P value < 0.001), and low hospital volume (< 50 procedures). Our study noted a decline in AF ablation-related hospitalizations and complications associated with the procedure. These findings largely reflect shifting trends of outpatient performance of the procedure and increasing safety profile due to improved institutional expertise and catheter techniques. © 2018 Wiley Periodicals, Inc.

Trends in thermal discomfort indices over western coastal cities of India

NASA Astrophysics Data System (ADS)

Desai, Manasi S.; Dhorde, Amit G.

2018-02-01

The present research aimed at analyzing temporal trends in thermal discomfort indices for a period of 46 years from 1969 to 2014 over western coastal region of India for seven urban centers during the months of pre-monsoon and monsoon seasons. Direct thermal discomfort indices employed for this purpose were thermo-hygrometric index (THI) and heat index (HI). Statistical techniques applied for obtaining temporal trends were linear regression model and Mann-Kendall (MK) rank test. Statistical significance of the obtained trends was evaluated at 95% confidence level. Sequential MK (SQ-MK) test was used for change point detection. To investigate actual incidences of thermal discomfort, daily index values were averaged for standard meteorological weeks (SMWs) over the study period and decadal percentage of thermal discomfort during SMWs was estimated. Trend analysis of selected meteorological parameters such as dry bulb temperature (DBT), wet bulb temperature (WBT), relative humidity (RH), and wind speed (WS) were investigated, which might be responsible for variation in thermal discomfort over the period. The results obtained depicted significant increase in thermal discomfort over the cities located on the southern part of west coast, while significant increase was observed during monsoon season months compared to pre-monsoon season. Decadal variation in percentage of SMWs falling in various discomfort categories was studied. At majority of the stations, moderate and high-risk SMWs have increased over the last two decades. The results of change point detection for THI and HI denoted significant increase at most of the stations after 1990s. The study validates increase in thermal discomfort vulnerability, particularly at thriving urban centers of western coastal region of India.

Statistical performance and information content of time lag analysis and redundancy analysis in time series modeling.

PubMed

Angeler, David G; Viedma, Olga; Moreno, José M

2009-11-01

Time lag analysis (TLA) is a distance-based approach used to study temporal dynamics of ecological communities by measuring community dissimilarity over increasing time lags. Despite its increased use in recent years, its performance in comparison with other more direct methods (i.e., canonical ordination) has not been evaluated. This study fills this gap using extensive simulations and real data sets from experimental temporary ponds (true zooplankton communities) and landscape studies (landscape categories as pseudo-communities) that differ in community structure and anthropogenic stress history. Modeling time with a principal coordinate of neighborhood matrices (PCNM) approach, the canonical ordination technique (redundancy analysis; RDA) consistently outperformed the other statistical tests (i.e., TLAs, Mantel test, and RDA based on linear time trends) using all real data. In addition, the RDA-PCNM revealed different patterns of temporal change, and the strength of each individual time pattern, in terms of adjusted variance explained, could be evaluated, It also identified species contributions to these patterns of temporal change. This additional information is not provided by distance-based methods. The simulation study revealed better Type I error properties of the canonical ordination techniques compared with the distance-based approaches when no deterministic component of change was imposed on the communities. The simulation also revealed that strong emphasis on uniform deterministic change and low variability at other temporal scales is needed to result in decreased statistical power of the RDA-PCNM approach relative to the other methods. Based on the statistical performance of and information content provided by RDA-PCNM models, this technique serves ecologists as a powerful tool for modeling temporal change of ecological (pseudo-) communities.

Intellectual property in holographic interferometry

NASA Astrophysics Data System (ADS)

Reingand, Nadya; Hunt, David

2006-08-01

This paper presents an overview of patents and patent applications on holographic interferometry, and highlights the possibilities offered by patent searching and analysis. Thousands of patent documents relevant to holographic interferometry were uncovered by the study. The search was performed in the following databases: U.S. Patent Office, European Patent Office, Japanese Patent Office and Korean Patent Office for the time frame from 1971 through May 2006. The patent analysis unveils trends in patent temporal distribution, patent families formation, significant technological coverage within the market of system that employ holographic interferometry and other interesting insights.

Empirical Corrections for MISR Calibration Temporal Trends, Point-Spread Function, Flat-Fielding, and Ghosting

NASA Astrophysics Data System (ADS)

Limbacher, J.; Kahn, R. A.

2015-12-01

MISR aerosol optical depth retrievals are fairly robust to small radiometric calibration artifacts, due to the multi-angle observations. However, even small errors in the MISR calibration, especially structured artifacts in the imagery, have a disproportionate effect on the retrieval of aerosol properties from these data. Using MODIS, POLDER-3, AERONET, MAN, and MISR lunar images, we diagnose and correct various calibration and radiometric artifacts found in the MISR radiance (Level 1) data, using empirical image analysis. The calibration artifacts include temporal trends in MISR top-of-atmosphere reflectance at relatively stable desert sites and flat-fielding artifacts detected by comparison to MODIS over bright, low-contrast scenes. The radiometric artifacts include ghosting (as compared to MODIS, POLDER-3, and forward model results) and point-spread function mischaracterization (using the MISR lunar data and MODIS). We minimize the artifacts to the extent possible by parametrically modeling the artifacts and then removing them from the radiance (reflectance) data. Validation is performed using non-training scenes (reflectance comparison), and also by using the MISR Research Aerosol retrieval algorithm results compared to MAN and AERONET.

Temporal trends in emergency department visits for bronchiolitis in the United States, 2006 to 2010.

PubMed

Hasegawa, Kohei; Tsugawa, Yusuke; Brown, David F M; Mansbach, Jonathan M; Camargo, Carlos A

2014-01-01

To examine temporal trends in emergency departments (EDs) visits for bronchiolitis among US children between 2006 and 2010. Serial, cross-sectional analysis of the Nationwide Emergency Department Sample, a nationally representative sample of ED patients. We used International Classification of Diseases, Ninth Revision, Clinical Modification code 466.1 to identify children <2 years of age with bronchiolitis. Primary outcome measures were rate of bronchiolitis ED visits, hospital admission rate and ED charges. Between 2006 and 2010, weighted national discharge data included 1,435,110 ED visits with bronchiolitis. There was a modest increase in the rate of bronchiolitis ED visits, from 35.6 to 36.3 per 1000 person-years (2% increase; Ptrend = 0.008), due to increases in the ED visit rate among children from 12 months to 23 months (24% increase;Ptrend < 0.001). By contrast, there was a significant decline in the ED visit rate among infants (4% decrease; Ptrend < 0.001). Although unadjusted admission rate did not change between 2006 and 2010 (26% in both years), admission rate declined significantly after adjusting for potential patient- and ED-level confounders (adjusted odds ratio for comparison of 2010 with 2006, 0.84; 95% confidence interval: 0.76-0.93; P < 0.001). Nationwide ED charges for bronchiolitis increased from $337 million to $389 million (16% increase; Ptrend < 0.001), adjusted for inflation. This increase was driven by a rise in geometric mean of ED charges per case from $887 to $1059 (19% increase; Ptrend < 0.001). Between 2006 and 2010, we found a divergent temporal trend in the rate of bronchiolitis ED visits by age group. Despite a significant increase in associated ED charges, ED-associated hospital admission rates for bronchiolitis significantly decreased over this same period.

Temporal trends in critical events complicating HIV infection: 1999-2010 multicentre cohort study in France.

PubMed

Barbier, François; Roux, Antoine; Canet, Emmanuel; Martel-Samb, Patricia; Aegerter, Philippe; Wolff, Michel; Guidet, Bertrand; Azoulay, Elie

2014-12-01

Multicentre data are limited to appraise the management and prognosis of critically ill human immunodeficiency virus (HIV)-infected patients. We sought to describe temporal trends in demographic and clinical characteristics, indications for intensive care and outcome in this patient population. We conducted a cohort study of unselected HIV-infected patients admitted between 1999 and 2010 to 34 French ICUs contributing to the CUB-Réa prospective database. We included 6,373 consecutive patients. Over the 12-year period, increases occurred in median age (39 years in 1999-2001; 47 years in 2008-2010, p < 0.0001) and prevalence of comorbidities (notably malignancies, from 6.7 to 16.4%, p < 0.0001). Admissions for respiratory failure (39.8% overall), shock (8.1%) and coma (22.7%) decreased (p < 0.0001), while those for sepsis (19.3%) remained stable. The main final diagnoses were bacterial sepsis (24.6%) and non-bacterial acquired immune deficiency syndrome (AIDS)-defining diseases (steady decline from 26.0 to 17.5%, p < 0.0001). Patients increasingly received mechanical ventilation (from 42.9 to 54.0%) and renal replacement therapy (from 9.6 to 16.8%) (p < 0.0001), whereas vasopressor use remained stable (27.4%). ICU readmissions increased after 2004 (p < 0.0001). ICU and hospital mortality (17.6 and 26.9%, respectively) dropped markedly in the most severely ill patients requiring multiple life-sustaining therapies. Malignancies and chronic liver disease were heavily associated with hospital mortality by multivariate analysis, while the most common AIDS-defining complications (Pneumocystis jirovecii pneumonia, cerebral toxoplasmosis and tuberculosis) had no independent impact. Progressive ageing, increasing prevalence of comorbidities (mainly malignancies), a steady decline in AIDS-related illnesses and improved benefits from life-sustaining therapies were the main temporal trends in HIV-infected patients requiring ICU admission.

Spatial and temporal trends of selected trace elements in liver tissue from polar bears (Ursus maritimus) from Alaska, Canada and Greenland.

PubMed

Routti, Heli; Letcher, Robert J; Born, Erik W; Branigan, Marsha; Dietz, Rune; Evans, Thomas J; Fisk, Aaron T; Peacock, Elizabeth; Sonne, Christian

2011-08-01

Spatial trends and comparative changes in time of selected trace elements were studied in liver tissue from polar bears from ten different subpopulation locations in Alaska, Canadian Arctic and East Greenland. For nine of the trace elements (As, Cd, Cu, Hg, Mn, Pb, Rb, Se and Zn) spatial trends were investigated in 136 specimens sampled during 2005-2008 from bears from these ten subpopulations. Concentrations of Hg, Se and As were highest in the (northern and southern) Beaufort Sea area and lowest in (western and southern) Hudson Bay area and Chukchi/Bering Sea. In contrast, concentrations of Cd showed an increasing trend from east to west. Minor or no spatial trends were observed for Cu, Mn, Rb and Zn. Spatial trends were in agreement with previous studies, possibly explained by natural phenomena. To assess temporal changes of Cd, Hg, Se and Zn concentrations during the last decades, we compared our results to previously published data. These time comparisons suggested recent Hg increase in East Greenland polar bears. This may be related to Hg emissions and/or climate-induced changes in Hg cycles or changes in the polar bear food web related to global warming. Also, Hg:Se molar ratio has increased in East Greenland polar bears, which suggests there may be an increased risk for Hg(2+)-mediated toxicity. Since the underlying reasons for spatial trends or changes in time of trace elements in the Arctic are still largely unknown, future studies should focus on the role of changing climate and trace metal emissions on geographical and temporal trends of trace elements.

Spatial and temporal trends of selected trace elements in liver tissue from polar bears (Ursus maritimus) from Alaska, Canada and Greenland

USGS Publications Warehouse

Routti, H.; Letcher, R.J.; Born, E.W.; Branigan, M.; Dietz, R.; Evans, T.J.; Fisk, A.T.; Peacock, E.; Sonne, C.

2011-01-01

Spatial trends and comparative changes in time of selected trace elements were studied in liver tissue from polar bears from ten different subpopulation locations in Alaska, Canadian Arctic and East Greenland. For nine of the trace elements (As, Cd, Cu, Hg, Mn, Pb, Rb, Se and Zn) spatial trends were investigated in 136 specimens sampled during 2005-2008 from bears from these ten subpopulations. Concentrations of Hg, Se and As were highest in the (northern and southern) Beaufort Sea area and lowest in (western and southern) Hudson Bay area and Chukchi/Bering Sea. In contrast, concentrations of Cd showed an increasing trend from east to west. Minor or no spatial trends were observed for Cu, Mn, Rb and Zn. Spatial trends were in agreement with previous studies, possibly explained by natural phenomena. To assess temporal changes of Cd, Hg, Se and Zn concentrations during the last decades, we compared our results to previously published data. These time comparisons suggested recent Hg increase in East Greenland polar bears. This may be related to Hg emissions and/or climate-induced changes in Hg cycles or changes in the polar bear food web related to global warming. Also, Hg:Se molar ratio has increased in East Greenland polar bears, which suggests there may be an increased risk for Hg 2+-mediated toxicity. Since the underlying reasons for spatial trends or changes in time of trace elements in the Arctic are still largely unknown, future studies should focus on the role of changing climate and trace metal emissions on geographical and temporal trends of trace elements. ?? 2011 The Royal Society of Chemistry.

40 years of progress in female cancer death risk: a Bayesian spatio-temporal mapping analysis in Switzerland.

PubMed

Herrmann, Christian; Ess, Silvia; Thürlimann, Beat; Probst-Hensch, Nicole; Vounatsou, Penelope

2015-10-09

In the past decades, mortality of female gender related cancers declined in Switzerland and other developed countries. Differences in the decrease and in spatial patterns within Switzerland have been reported according to urbanisation and language region, and remain controversial. We aimed to investigate geographical and temporal trends of breast, ovarian, cervical and uterine cancer mortality, assess whether differential trends exist and to provide updated results until 2011. Breast, ovarian, cervical and uterine cancer mortality and population data for Switzerland in the period 1969-2011 was retrieved from the Swiss Federal Statistical office (FSO). Cases were grouped into <55 year olds, 55-74 year olds and 75+ year olds. The geographical unit of analysis was the municipality. To explore age- specific spatio-temporal patterns we fitted Bayesian hierarchical spatio-temporal models on subgroup-specific death rates indirectly standardized by national references. We used linguistic region and degree of urbanisation as covariates. Female cancer mortality continuously decreased in terms of rates in all age groups and cancer sites except for ovarian cancer in 75+ year olds, especially since 1990 onwards. Contrary to other reports, we found no systematic difference between language regions. Urbanisation as a proxy for access to and quality of medical services, education and health consciousness seemed to have no influence on cancer mortality with the exception of uterine and ovarian cancer in specific age groups. We observed no obvious spatial pattern of mortality common for all cancer sites. Rate reduction in cervical cancer was even stronger than for other cancer sites. Female gender related cancer mortality is continuously decreasing in Switzerland since 1990. Geographical differences are small, present on a regional or canton-overspanning level, and different for each cancer site and age group. No general significant association with cantonal or language region borders could be observed.

Spatial and temporal stability of temperature in the first-level basins of China during 1951-2013

NASA Astrophysics Data System (ADS)

Cheng, Yuting; Li, Peng; Xu, Guoce; Li, Zhanbin; Cheng, Shengdong; Wang, Bin; Zhao, Binhua

2018-05-01

In recent years, global warming has attracted great attention around the world. Temperature change is not only involved in global climate change but also closely linked to economic development, the ecological environment, and agricultural production. In this study, based on temperature data recorded by 756 meteorological stations in China during 1951-2013, the spatial and temporal stability characteristics of annual temperature in China and its first-level basins were investigated using the rank correlation coefficient method, the relative difference method, rescaled range (R/S) analysis, and wavelet transforms. The results showed that during 1951-2013, the spatial variation of annual temperature belonged to moderate variability in the national level. Among the first-level basins, the largest variation coefficient was 114% in the Songhuajiang basin and the smallest variation coefficient was 10% in the Huaihe basin. During 1951-2013, the spatial distribution pattern of annual temperature presented extremely strong spatial and temporal stability characteristics in the national level. The variation range of Spearman's rank correlation coefficient was 0.97-0.99, and the spatial distribution pattern of annual temperature showed an increasing trend. In the national level, the Liaohe basin, the rivers in the southwestern region, the Haihe basin, the Yellow River basin, the Yangtze River basin, the Huaihe basin, the rivers in the southeastern region, and the Pearl River basin all had representative meteorological stations for annual temperature. In the Songhuajiang basin and the rivers in the northwestern region, there was no representative meteorological station. R/S analysis, the Mann-Kendall test, and the Morlet wavelet analysis of annual temperature showed that the best representative meteorological station could reflect the variation trend and the main periodic changes of annual temperature in the region. Therefore, strong temporal stability characteristics exist for annual temperature in China and its first-level basins. It was therefore feasible to estimate the annual average temperature by the annual temperature recorded by the representative meteorological station in the region. Moreover, it was of great significance to assess average temperature changes quickly and forecast future change tendencies in the region.

Multidecadal Atlantic climate variability and its impact on marine pelagic communities

NASA Astrophysics Data System (ADS)

Harris, Victoria; Edwards, Martin; Olhede, Sofia C.

2014-05-01

A large scale analysis of sea surface temperature (SST) and climate variability over the North Atlantic and its interactions with plankton over the North East Atlantic was carried out to better understand what drives both temperature and species abundance. The spatio-temporal pattern of SST was found to correspond to known climate indices, namely the Atlantic Multidecadal Oscillation (AMO), the East Atlantic Pattern (EAP) and the North Atlantic Oscillation (NAO). The spatial influence of these indices is heterogeneous. Although the AMO is present across all regions, it is most strongly represented in the SST signal in the subpolar gyre region. The NAO instead is strongly weighted in the North Sea and the pattern of its influence is oscillatory in space with a wavelength of approximately 6000 km. Natural oscillations might obscure the influence of climate change effects, making it difficult to determine how much of the variation is attributable to longer term trends. In order to separate the influences of different climate signals the SST signals were decomposed in to spatial and temporal components using principal component analysis (PCA). A similar analysis is carried out on various indicator species of plankton: Calanus finmarchicus, Phytoplankton Colour Index and total copepod abundance, as well as phytoplankton and zooplankton communities. By comparing the two outputs it is apparent that the dominant driver is the recent warming trend, which has a negative influence on C. finmarchicus and total copepods, but has a positive one on phytoplankton colour. However natural oscillations also influence the abundance of plankton, in particular the AMO is a driver of diatom abundance. Fourier principal component analysis, an approach which is novel in terms of the ecological data, was used to analyse the behaviour of various communities averaged over space. The zooplankton community is found to be primarily influenced by climate warming trends. The analysis provides compelling evidence for the hypothesis that cold water species are gradually being replaced by more temperate species in the North Atlantic. This may have detrimental effects for the entire marine ecosystem, by affecting on organisms such as fish larva for example. The second group, a phytoplankton subset consisting primarily of diatom species, is primarily influenced by the AMO rather than the average temperature trend. This result highlights the importance of natural oscillations to certain functional groups, in particular those subgroups which are less directly metabolically affected by changes in temperature.

Rainfall Patterns Analysis over Ampangan Muda, Kedah from 2007 - 2016

NASA Astrophysics Data System (ADS)

Chooi Tan, Kok

2018-04-01

The scientific knowledge about climate change and climate variability over Malaysia pertaining to the extreme water-related disaster such as drought and flood. A deficit or increment in precipitation occurred over the past century becomes a useful tool to understand the climate change in Malaysia. The purpose of this work is to examine the rainfall patterns over Ampangan Muda, Kedah. Daily rainfall data is acquired from Malaysian Meteorological Department to analyse the temporal and trends of the monthly and annual rainfall over the study area from 2007 to 2016. The obtained results show that the temporal and patterns of the rainfall over Ampangan Muda, Kedah is largely affected by the regional phenomena such as monsoon, El Niño Southern Oscillation (ENSO), and the Madden-Julian Oscillation. In addition, backward trajectories analysis is also used to identify the patterns for long-range of synoptic circulation over the region.

A new perspective on global mean sea level (GMSL) acceleration

NASA Astrophysics Data System (ADS)

Watson, Phil J.

2016-06-01

The vast body of contemporary climate change science is largely underpinned by the premise of a measured acceleration from anthropogenic forcings evident in key climate change proxies -- greenhouse gas emissions, temperature, and mean sea level. By virtue, over recent years, the issue of whether or not there is a measurable acceleration in global mean sea level has resulted in fierce, widespread professional, social, and political debate. Attempts to measure acceleration in global mean sea level (GMSL) have often used comparatively crude analysis techniques providing little temporal instruction on these key questions. This work proposes improved techniques to measure real-time velocity and acceleration based on five GMSL reconstructions spanning the time frame from 1807 to 2014 with substantially improved temporal resolution. While this analysis highlights key differences between the respective reconstructions, there is now more robust, convincing evidence of recent acceleration in the trend of GMSL.

An innovative procedure to assess multi-scale temporal trends in groundwater quality: Example of the nitrate in the Seine-Normandy basin, France

NASA Astrophysics Data System (ADS)

Lopez, Benjamin; Baran, Nicole; Bourgine, Bernard

2015-03-01

The European Water Framework Directive (WFD) asks Member States to identify trends in contaminant concentrations in groundwater and to take measures to reach a good chemical status by 2015. In this study, carried out in a large hydrological basin (95,300 km2), an innovative procedure is described for the assessment of recent trends in groundwater nitrate concentrations both at sampling point and regional scales. Temporal variograms of piezometric and nitrate concentration time series are automatically calculated and fitted in order to classify groundwater according to their temporal pattern. These results are then coupled with aquifer lithology to map spatial units within which the modes of diffuse transport of contaminants towards groundwater are assumed to be the same at all points. These spatial units are suitable for evaluating regional trends. The stability over time of the time series is tested based on the cumulative sum principle, to determine the time period during which the trend should be sought. The Mann-Kendall and Regional-Kendall nonparametric tests for monotonic trends, coupled with the Sen-slope test, are applied to the periods following the point breaks thus determined at both the sampling point or regional scales. This novel procedure is robust and enables rapid processing of large databases of raw data. It would therefore be useful for managing groundwater quality in compliance with the aims of the WFD.

Estimating uncertainty and its temporal variation related to global climate models in quantifying climate change impacts on hydrology

NASA Astrophysics Data System (ADS)

Shen, Mingxi; Chen, Jie; Zhuan, Meijia; Chen, Hua; Xu, Chong-Yu; Xiong, Lihua

2018-01-01

Uncertainty estimation of climate change impacts on hydrology has received much attention in the research community. The choice of a global climate model (GCM) is usually considered as the largest contributor to the uncertainty of climate change impacts. The temporal variation of GCM uncertainty needs to be investigated for making long-term decisions to deal with climate change. Accordingly, this study investigated the temporal variation (mainly long-term) of uncertainty related to the choice of a GCM in predicting climate change impacts on hydrology by using multi-GCMs over multiple continuous future periods. Specifically, twenty CMIP5 GCMs under RCP4.5 and RCP8.5 emission scenarios were adapted to adequately represent this uncertainty envelope, fifty-one 30-year future periods moving from 2021 to 2100 with 1-year interval were produced to express the temporal variation. Future climatic and hydrological regimes over all future periods were compared to those in the reference period (1971-2000) using a set of metrics, including mean and extremes. The periodicity of climatic and hydrological changes and their uncertainty were analyzed using wavelet analysis, while the trend was analyzed using Mann-Kendall trend test and regression analysis. The results showed that both future climate change (precipitation and temperature) and hydrological response predicted by the twenty GCMs were highly uncertain, and the uncertainty increased significantly over time. For example, the change of mean annual precipitation increased from 1.4% in 2021-2050 to 6.5% in 2071-2100 for RCP4.5 in terms of the median value of multi-models, but the projected uncertainty reached 21.7% in 2021-2050 and 25.1% in 2071-2100 for RCP4.5. The uncertainty under a high emission scenario (RCP8.5) was much larger than that under a relatively low emission scenario (RCP4.5). Almost all climatic and hydrological regimes and their uncertainty did not show significant periodicity at the P = .05 significance level, but their temporal variation could be well modeled by using the fourth-order polynomial. Overall, this study further emphasized the importance of using multiple GCMs for studying climate change impacts on hydrology. Furthermore, the temporal variation of uncertainty sourced from GCMs should be given more attention.

Incorporating diverse data and realistic complexity into demographic estimation procedures for sea otters

USGS Publications Warehouse

Tinker, M. Timothy; Doak, Daniel F.; Estes, James A.; Hatfield, Brian B.; Staedler, Michelle M.; Gross, Arthur

2006-01-01

Reliable information on historical and current population dynamics is central to understanding patterns of growth and decline in animal populations. We developed a maximum likelihood-based analysis to estimate spatial and temporal trends in age/sex-specific survival rates for the threatened southern sea otter (Enhydra lutris nereis), using annual population censuses and the age structure of salvaged carcass collections. We evaluated a wide range of possible spatial and temporal effects and used model averaging to incorporate model uncertainty into the resulting estimates of key vital rates and their variances. We compared these results to current demographic parameters estimated in a telemetry-based study conducted between 2001 and 2004. These results show that survival has decreased substantially from the early 1990s to the present and is generally lowest in the north-central portion of the population's range. The greatest temporal decrease in survival was for adult females, and variation in the survival of this age/sex class is primarily responsible for regulating population growth and driving population trends. Our results can be used to focus future research on southern sea otters by highlighting the life history stages and mortality factors most relevant to conservation. More broadly, we have illustrated how the powerful and relatively straightforward tools of information-theoretic-based model fitting can be used to sort through and parameterize quite complex demographic modeling frameworks. ?? 2006 by the Ecological Society of America.

Temporal and Longitudinal Mercury Trends in Burbot (Lota lota) in the Russian Arctic.

PubMed

Pelletier, Alexander R; Castello, Leandro; Zhulidov, Alexander V; Gurtovaya, Tatiana Yu; Robarts, Richard D; Holmes, Robert M; Zhulidov, Daniel A; Spencer, Robert G M

2017-11-21

Current understanding of mercury (Hg) dynamics in the Arctic is hampered by a lack of data in the Russian Arctic region, which comprises about half of the entire Arctic watershed. This study quantified temporal and longitudinal trends in total mercury (THg) concentrations in burbot (Lota lota) in eight rivers of the Russian Arctic between 1980 and 2001, encompassing an expanse of 118 degrees of longitude. Burbot THg concentrations declined by an average of 2.6% annually across all eight rivers during the study period, decreasing by 39% from 0.171 μg g -1 wet weight (w.w.) in 1980 to 0.104 μg g -1 w.w. in 2001. THg concentrations in burbot also declined by an average of 1.8% per 10° of longitude from west to east across the study area between 1988 and 2001. These results, in combination with those of previous studies, suggest that Hg trends in Arctic freshwater fishes before 2001 were spatially and temporally heterogeneous, as those in the North American Arctic were mostly increasing while those in the Russian Arctic were mostly decreasing. It is suggested that Hg trends in Arctic animals may be influenced by both depositional and postdepositional processes.

Temporal trends in physical activity: a systematic review.

PubMed

Knuth, Alan G; Hallal, Pedro C

2009-09-01

In spite of all accumulated scientific knowledge on the benefits of physical activity (PA) for health, high rates of sedentary lifestyle are still observed worldwide. The aim of this study was to systematically review articles on temporal trends of PA and fitness, with emphasis on differences between children/ adolescents and adults. An electronic search at the Medline/PubMed database was carried out using the following combination of keywords: temporal trends or trends or surveillance or monitoring and PA or exercise or physical fitness or motor activity or sedentary or fitness. By using this strategy, 23,088 manuscripts were detected. After examination, 41 articles fulfilled all inclusion criteria, and were, therefore, included. The data currently available in the literature for adults shows that leisure-time activity levels tend to be increasing over time, while occupational-related PA is decreasing over time. Youth PA seems to be decreasing over time, including a lower level of activity in physical education classes. As a consequence, fitness levels are also declining. PA surveillance must be strongly encouraged in all settings and age groups. Special attention must be paid to low and middle-income countries, where PA surveillance is virtually inexistent.

Assessment of long-term monthly and seasonal trends of warm (cold), wet (dry) spells in Kansas, USA

NASA Astrophysics Data System (ADS)

Dokoohaki, H.; Anandhi, A.

2013-12-01

A few recent studies have focused on trends in rainfall, temperature, and frost indicators at different temporal scales using centennial weather station data in Kansas; our study supplements this work by assessing the changes in spell indicators in Kansas. These indicators provide the duration between temperature-based (warm and cold) and precipitation-based (wet and dry) spells. For wet (dry) spell calculations, a wet day is defined as a day with precipitation ≥1 mm, and a dry day is defined as one with precipitation ≤1 mm. For warm (cold) spell calculations, a warm day is defined as a day with maximum temperature >90th percentile of daily maximum temperature, and a cold day is defined as a day with minimum temperature <10th percentile of daily minimum temperature. The percentiles are calculated for 1971-2000, and four spell indicators are calculated: Average Wet Spell Length (AWSL), Dry Spell Length (ADSL), Average Warm Spell Days (AWSD) and Average Cold Spell Days (ACSD) are calculated. Data were provided from 23 centennial weather stations across Kansas, and all calculations were done for four time periods (through 1919, 1920-1949, 1950-1979, and 1980-2009). The definitions and software provided by Expert Team on Climate Change Detection and Indices (ETCCDI) were adapted for application to Kansas. The long- and short-term trends in these indices were analyzed at monthly and seasonal timescales. Monthly results indicate that ADSL is decreasing and AWSL is increasing throughout the state. AWSD and ACSD both showed an overall decreasing trend, but AWSD trends were variable during the beginning of the Industrial Revolution. Results of seasonal analysis revealed that the fall season recorded the greatest increasing trend for ACSD and the greatest decreasing trend for AWSD across the whole state and during all time periods. Similarly, the greatest increasing and decreasing trends occurred in winter for AWSL and ADSL, respectively. These variations can be important indicators of climatic change that may not be represented in mean conditions. Detailed geographical and temporal variations of the spell indices also can be beneficial for updating management decisions and providing adaptation recommendations for local and regional agricultural production.

A Lagrangian analysis of mid-latitude stratospheric ozone variability and long-term trends.

NASA Astrophysics Data System (ADS)

Koch, G.; Wernli, H.; Staehelin, J.; Peter, T.

2002-05-01

A systematic Lagrangian investigation is performed of wintertime high-resolution stratospheric ozone soundings at Payerne, Switzerland, from January 1970 to March 2001. For every ozone sounding, 10-day backward trajectories have been calculated on 16 isentropic levels using NCEP reanalysis data. Both the minimum/maximum latitude and potential vorticity (PV) averaged along the trajectories are used as indicators of the air parcels' ``origin''. The importance of transport for the understandin g of single ozone profiles is confirmed by a statistical analysis which shows that negative/positive ozone deviations gener ally coincide with transport from regions with climatologically low/high ozone values. The stable relationship between PV and ozone for the 32 year period indicates either no direct chemical impact or no temporal change of this impact. In the upper layer the PV-ozone relationship changes significantly after 1987 and a separate trend analysis for air masses transported from the polar, midlatitude and subtropical regions shows negative ozone trends in all three categories (with a maximum for the polar region). This is not direct evidence for, but would be in agreement with, an increased chemical ozone depletion in the Arctic since the late 1980s. The reasons for the negative trend in the mid-stratospheric air masses with subtropical origin that are in qualitative agreement with recent satellite observations are presently unknown.

Recurrent jellyfish blooms are a consequence of global oscillations.

PubMed

Condon, Robert H; Duarte, Carlos M; Pitt, Kylie A; Robinson, Kelly L; Lucas, Cathy H; Sutherland, Kelly R; Mianzan, Hermes W; Bogeberg, Molly; Purcell, Jennifer E; Decker, Mary Beth; Uye, Shin-ichi; Madin, Laurence P; Brodeur, Richard D; Haddock, Steven H D; Malej, Alenka; Parry, Gregory D; Eriksen, Elena; Quiñones, Javier; Acha, Marcelo; Harvey, Michel; Arthur, James M; Graham, William M

2013-01-15

A perceived recent increase in global jellyfish abundance has been portrayed as a symptom of degraded oceans. This perception is based primarily on a few case studies and anecdotal evidence, but a formal analysis of global temporal trends in jellyfish populations has been missing. Here, we analyze all available long-term datasets on changes in jellyfish abundance across multiple coastal stations, using linear and logistic mixed models and effect-size analysis to show that there is no robust evidence for a global increase in jellyfish. Although there has been a small linear increase in jellyfish since the 1970s, this trend was unsubstantiated by effect-size analysis that showed no difference in the proportion of increasing vs. decreasing jellyfish populations over all time periods examined. Rather, the strongest nonrandom trend indicated jellyfish populations undergo larger, worldwide oscillations with an approximate 20-y periodicity, including a rising phase during the 1990s that contributed to the perception of a global increase in jellyfish abundance. Sustained monitoring is required over the next decade to elucidate with statistical confidence whether the weak increasing linear trend in jellyfish after 1970 is an actual shift in the baseline or part of an oscillation. Irrespective of the nature of increase, given the potential damage posed by jellyfish blooms to fisheries, tourism, and other human industries, our findings foretell recurrent phases of rise and fall in jellyfish populations that society should be prepared to face.

A multi-criteria evaluation system for marine litter pollution based on statistical analyses of OSPAR beach litter monitoring time series.

PubMed

Schulz, Marcus; Neumann, Daniel; Fleet, David M; Matthies, Michael

2013-12-01

During the last decades, marine pollution with anthropogenic litter has become a worldwide major environmental concern. Standardized monitoring of litter since 2001 on 78 beaches selected within the framework of the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) has been used to identify temporal trends of marine litter. Based on statistical analyses of this dataset a two-part multi-criteria evaluation system for beach litter pollution of the North-East Atlantic and the North Sea is proposed. Canonical correlation analyses, linear regression analyses, and non-parametric analyses of variance were used to identify different temporal trends. A classification of beaches was derived from cluster analyses and served to define different states of beach quality according to abundances of 17 input variables. The evaluation system is easily applicable and relies on the above-mentioned classification and on significant temporal trends implied by significant rank correlations. Copyright © 2013 Elsevier Ltd. All rights reserved.

Temporal and spatial characteristics of annual and seasonal rainfall in Malawi

NASA Astrophysics Data System (ADS)

Ngongondo, Cosmo; Xu, Chong-Yu; Gottschalk, Lars; Tallaksen, Lena M.; Alemaw, Berhanu

2010-05-01

An understanding of the temporal and spatial characteristics of rainfall is central to water resources planning and management. However, such information is often limited in many developing countries like Malawi. In an effort to bridge the information gap, this study examined the temporal and spatial charecteristics of rainfall in Malawi. Rainfall readings from 42 stations across Malawi from 1960 to 2006 were analysed at monthly, annual and seasonal scales. The Malawian rainfall season lasts from November to April. The data were firstly subjected to quality checks through the cumulative deviations test and the Standard Normal Homogeinity Test (SNHT). Monthly distribution in a typical year, called heterogeneity, was investigated using the Precipitation Concentration Index (PCI). Further, normalized precipitation anomaly series of annual rainfall series (AR) and the PCI (APCI) were used to test for interannual rainfall variability. Spatial variability was characterised by fitting the Spatial Correlation function (SCF). The nonparametric Mann-Kendall statistic was used to investigate the temporal trends of the various rainfall variables. The results showed that 40 of the stations passed both data quality tests. For the two stations that failed, the data were adjusted using nearby stations. Annual and seasonal rainfall were found to be characterised by high spatial variation. The country mean annual rainfall was 1095 mm with mean interannual variability of 26%. The highland areas to the north and southeast of the country exhibited the highest rainfall and lowest interannual variability. Lowest rainfall coupled with high interannual variability was found in the Lower Shire basin, in the southern part of Malawi. This simillarity is the pattern of annual and seasonal rainfall should be expected because all stations had over 90% of their observed annual rainfall in the six month period between November and April. Monthly rainfall was found to be highly variable both temporally and spatially. None of the stations have stable monthly rainfall regimes (mean PCI of less than 10). Stations with the highest mean rainfall were found to have a lower interannual variability. The rainfall stations showed low spatial correlations for annual, monthly as well as seasonal timescales indicating that the data may not be suitable for spatial interpolation. However, some structure (i.e. lower correlation with distance) could be observed when aggregating the data at 50 mile intervals. The annual and seasonal rainfall series were dominated by negative trends. The spatial distribution of the trends can be described as heterogeneous, although most of the stations in the southern region have negative trends. At the monthly timescale, 37 of the stations show a negative trend with four of the stations, all in the south, showing significant negative trends. On the other hand, only 5 stations show positive trends with only one significant trend in the south. Keywords: Malawi, rainfall trends, spatial variation

Temporal trends in dietary supplement prescriptions of United States military service members suggest a decrease in pyridoxine and increase in vitamin D supplements from 2005 to 2013.

PubMed

Knapik, Joseph J; T Jean, Rosenie; Austin, Krista G; Steelman, Ryan A; Gannon, Julia; Farina, Emily K; Lieberman, Harris R

2016-10-01

Dietary supplements (DSs) can be obtained over-the-counter but can also be prescribed by health-care providers for therapeutic reasons. Few studies have documented this later source despite the fact that 79% of physicians and 82% of nurses have recommended DSs to patients. This investigation assessed prevalence and temporal trends in oral DS prescriptions filled by all United States service members (SMs) from 2005 to 2013 (n = 1 427 080 ± 22 139, mean ± standard deviation (SD)/y). We hypothesize that there would be temporal variations in specific types of DSs. Data obtained from Department of Defense Pharmacy Data Transaction System were grouped by American Hospital Formulary System pharmacologic-therapeutic classifications and prevalence examined over time. About 11% of SMs filled one or more DS prescriptions of 235 180 ± 4926 (mean ± SD) prescriptions/y over the 9-year period. Curve-fitting techniques indicated significant linear declines over time for multivitamins (P = .004), iron preparations (P < .001), antacids (P < .001), and vitamin B and B complex vitamins (P < .001). There were significant quadratic trends indicating a rise in early years followed by a leveling off in later years for replacement preparations (P < .001) and vitamin C (P < .001). There were significant quadratic trends (P < .001) for vitamin E indicating a decline in early years and leveling off in later years, and vitamin D indicating little change in early years followed by a large rise subsequently (P < .001). This study identified temporal trends in specific DS categories that may be associated with changing perceptions of prescribers and/or patients of the appropriate roles of DSs in medicine and public health. Published by Elsevier Inc.

Temporal trends in dioxins (polychlorinated dibenzo-p-dioxin and dibenzofurans) and dioxin-like polychlorinated biphenyls in Baltic herring (Clupea harengus).

PubMed

Miller, Aroha; Hedman, Jenny E; Nyberg, Elisabeth; Haglund, Peter; Cousins, Ian T; Wiberg, Karin; Bignert, Anders

2013-08-15

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyl (dl-PCBs) concentrations in Baltic herring (Clupea harengus) have been relatively stable since the mid to late 1990s. It is unclear why concentrations in Baltic herring are not following the observed decreases in other environmental matrices. Here, changes in long-term temporal trends in Baltic herring were examined. A number of biological variables were examined alongside the temporal trends to investigate whether fish biology e.g., growth (length, weight, age), lipid content, reproductive phase or fishing date may provide an explanation for the temporal trends observed. Significant (p<0.05) decreasing trends were observed for PCDD/F toxic equivalents (TEQPCDD/F) at three of the four sites (lipid weight (lw) and wet weight (ww), Swedish west coast lw only); however, other TEQ values e.g., TEQPCDD, TEQPCDF, TEQdl-PCB, TEQPCDD/F+dl-PCB were inconsistent, decreasing at some sites but not others. In the most recent 10 years of data, fewer significant decreases were seen overall. Over the examined time period, significant decreases (Bothnian Bay, p<0.01, southern Baltic Proper, p<0.02) and increases (Swedish west coast, p<0.02) in lipid content, growth dilution or lack thereof, and significant changes in age were observed. However herring were not randomly selected which biases this result. Continual efforts to decrease PCDD/F and dl-PCB emissions and to locate/reduce hotspots are necessary, while bearing in mind that herring biology may be impeding faster decreases of these chemicals. Copyright © 2013 Elsevier Ltd. All rights reserved.

Spatial and temporal evaluation of long term trend (2005-2014) of OMI retrieved NO2 and SO2 concentrations in Henan Province, China

NASA Astrophysics Data System (ADS)

Zhang, Leishi; Lee, Chih Sheng; Zhang, Ruiqin; Chen, Liangfu

2017-04-01

Tropospheric NO2 and SO2 concentrations are of great importance with regard to air quality, atmospheric chemistry, and climate change. Due to lack of surface monitoring stations, this study analyzes long term trend of NO2 and SO2 levels (2005-2014), retrieved from Ozone Monitoring Instrument (OMI) board on the NASA's Aura satellite, in an important region of China - Henan Province. Henan Province, located in North China Plain, has encountered serious air pollution problems including extremely high PM2.5 concentrations and as one of the most polluted region in China. The satellite spatial images clearly show that high levels of both NO2 and SO2 are concentrated in north and northeastern regions with much lower levels observed in other parts of Henan. Both pollutants exhibit the highest levels in winter with the least in summer/spring. The temporal trend analysis based on moving average of deseasonalized and decyclic data indicates that for NO2, there is a continuous increasing pattern from 2005 to 2011 at 6.4% per year, thereafter, it shows a decreasing trend (10.6% per year). As for SO2, the increasing trend is about 16% per year from 2005 to 2007 with decreasing rate 7% per year from 2007 to 2014. The economic development with incredible annual 11% GDP growth in Henan is responsible for increasing levels of NO2 and SO2. The observed decreasing SO2 level starting in 2007 is due to reduced SO2 emission, utilization of flue gas desulfurization (FGD) devices and to some extent, in preparation of Beijing 2008 Olympic Games. On the other hand, increasing vehicle numbers (155% from 2006 to 2012) and coal consumption (37% during the same span), along with the lack of denitration process for removing flue/exhaust gas NOx are responsible for increasing NO2 trend until 2011. The ratio of SO2/NO2 started decreasing in 2007 and dropped significantly from 2011 to 2013 indicating good performance of FGD and ever increasing NOx contribution from mobile sources. Unlike those observed in developed countries (US, EU and Japan) where a decreasing trend for both SO2 and NO2 has been observed since 1990s, the observed upward and downward trend found in Henan is similar to those found in North China Plain and other parts of China. The spatial and temporal trend analyses of SO2 and NO2 in four other regions in Henan further indicate a similar trend to those observed in Henan Province, albeit with different increasing and decreasing rate. The results provide regulatory agency to develop action plans to combat air pollution problem in general and SO2 and NO2 problems in particular in Henan. The implications of our findings and recommendations for decision makers are discussed in the paper.

Trends of psychology-related research on euthanasia: a qualitative software-based thematic analysis of journal abstracts.

PubMed

Caputo, Andrea

2015-01-01

Euthanasia has received increasing attention in both academic and public debates as one of the most controversial issues. However, the contribution of psychology-related themes to the topic has had little role on these ongoing debates. The aim of the present study is twofold: (1) to explore the main themes relating to euthanasia as provided by psychology-related research; (2) to analyze the temporal trends of psychology-related research on euthanasia over the last decades. A comprehensive search of academic literature was conducted on PsychINFO database. A qualitative software-based thematic analysis was carried out on 602 journal abstracts published from 1935 to 2014. This study highlighted four different thematic areas which characterized the scientific discourse on euthanasia: (1) moral values, in terms of religious, philosophical, and social implications concerning the individual's decision to die; (2) professional ethics, in terms of health and social workers' legal responsibility in death assistance; (3) end-of-life care, with regard to medical options provided to support individuals nearing death; and (4) patient's right to healthcare, in terms of access to palliative care and better quality of dying. Euthanasia discourse over the last decades seems to be overall characterized by two main dimensions: (1) the increasing trend of social legitimacy and acceptability of euthanasia over time, which moved from ethical to healthcare issues; and (2) the curvilinear temporal trend about the request/provision process in euthanasia, which moved from patient's decision for ending life (mainly characterizing the most past and recent research) to the role of health professionals (with a peak in the 1990s). The results suggest palliative care as a potential future research area which can provide healthcare providers with skills to 'connect' with patients, understand patients' hidden agendas, and grant a good quality of life and dying process.

Spatio-temporal trends of rainfall across Indian river basins

NASA Astrophysics Data System (ADS)

Bisht, Deepak Singh; Chatterjee, Chandranath; Raghuwanshi, Narendra Singh; Sridhar, Venkataramana

2018-04-01

Daily gridded high-resolution rainfall data of India Meteorological Department at 0.25° spatial resolution (1901-2015) was analyzed to detect the trend in seasonal, annual, and maximum cumulative rainfall for 1, 2, 3, and 5 days. The present study was carried out for 85 river basins of India during 1901-2015 and pre- and post-urbanization era, i.e., 1901-1970 and 1971-2015, respectively. Mann-Kendall ( α = 0.05) and Theil-Sen's tests were employed for detecting the trend and percentage of change over the period of time, respectively. Daily extreme rainfall events, above 95 and 99 percentile threshold, were also analyzed to detect any trend in their magnitude and number of occurrences. The upward trend was found for the majority of the sub-basins for 1-, 2-, 3-, and 5-day maximum cumulative rainfall during the post-urbanization era. The magnitude of extreme threshold events is also found to be increasing in the majority of the river basins during the post-urbanization era. A 30-year moving window analysis further revealed a widespread upward trend in a number of extreme threshold rainfall events possibly due to urbanization and climatic factors. Overall trends studied against intra-basin trend across Ganga basin reveal the mixed pattern of trends due to inherent spatial heterogeneity of rainfall, therefore, highlighting the importance of scale for such studies.

Causes and emerging trends of childhood blindness: findings from schools for the blind in Southeast Nigeria.

PubMed

Aghaji, Ada; Okoye, Obiekwe; Bowman, Richard

2015-06-01

To ascertain the causes severe visual impairment and blindness (SVI/BL) in schools for the blind in southeast Nigeria and to evaluate temporal trends. All children who developed blindness at <15 years of age in all the three schools for the blind in southeast Nigeria were examined. All the data were recorded on a WHO/Prevention of Blindness (WHO/PBL) form entered into a Microsoft Access database and transferred to STATA V.12.1 for analysis. To estimate temporal trends in causes of blindness, older (>15 years) children were compared with younger (≤15 years) children. 124 children were identified with SVI/BL. The most common anatomical site of blindness was the lens (33.9%). Overall, avoidable blindness accounted for 73.4% of all blindness. Exploring trends in SVI/BL between children ≤15 years of age and those >15 years old, this study shows a reduction in avoidable blindness but an increase in cortical visual impairment in the younger age group. The results from this study show a statistically significant decrease in avoidable blindness in children ≤15 years old. Corneal blindness appears to be decreasing but cortical visual impairment seems to be emerging in the younger age group. Appropriate strategies for the prevention of avoidable childhood blindness in Nigeria need to be developed and implemented. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Mercury levels in herring gulls and fish: 42 years of spatio-temporal trends in the Great Lakes.

PubMed

Blukacz-Richards, E Agnes; Visha, Ariola; Graham, Matthew L; McGoldrick, Daryl L; de Solla, Shane R; Moore, David J; Arhonditsis, George B

2017-04-01

Total mercury levels in aquatic birds and fish communities have been monitored across the Canadian Great Lakes by Environment and Climate Change Canada (ECCC) for the past 42 years (1974-2015). These data (22 sites) were used to examine spatio-temporal variability of mercury levels in herring gull (Larus argentatus) eggs, lake trout (Salvelinus namaycush), walleye (Sander vitreus), and rainbow smelt (Osmerus mordax). Trends were quantified with dynamic linear models, which provided time-variant rates of change of mercury concentrations. Lipid content (in both fish and eggs) and length in fish were used as covariates in all models. For the first three decades, mercury levels in gull eggs and fish declined at all stations. In the 2000s, trends for herring gull eggs reversed at two sites in Lake Erie and two sites in Lake Ontario. Similar trend reversals in the 2000s were observed for lake trout in Lake Superior and at a single station in Lake Ontario. Mercury levels in lake trout continued to slowly decline at all of the remaining stations, except for Lake Huron, where the levels remained stable. A post-hoc Bayesian regression analysis suggests strong trophic interactions between herring gulls and rainbow smelt in Lake Superior and Lake Ontario, but also pinpoints the likelihood of a trophic decoupling in Lake Huron and Lake Erie. Continued monitoring of mercury levels in herring gulls and fish is required to consolidate these trophic shifts and further evaluate their broader implications. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, Tyler F; Jett, Robert Trent; Smith, John G.

A dike failure at the Tennessee Valley Authority Kingston Fossil Plant in East Tennessee, United States, in December 2008, released approximately 4.1 million m3 of coal ash into the Emory River. From 2009 through 2012, samples of mayfly nymphs ( Hexagenia bilineata) were collected each spring from sites in the Emory, Clinch, and Tennessee Rivers upstream and downstream of the spill. Samples were analyzed for 17 metals. Concentrations of metals were generally highest the first 2 miles downstream of the spill, and then decreased with increasing distance from the spill. Arsenic, B, Ba, Be, Mo, Sb, Se, Sr, and Vmore » appeared to have strong ash signatures, whereas Co, Cr, Cu, Ni, and Pb appeared to be associated with ash and other sources. Furthermore, the concentrations for most of these contaminants were modest and are unlikely to cause widespread negative ecological effects. Trends in Hg, Cd, and Zn suggested little (Hg) or no (Cd, Zn) association with ash. Temporal trends suggested that concentrations of ash-related contaminants began to subside after 2010, but because of the limited time period of that analysis (4 yr), further monitoring is needed to verify this trend. The present study provides important information on the magnitude of contaminant exposure to aquatic receptors from a major coal ash spill, as well as spatial and temporal trends for transport of the associated contaminants in a large open watershed. Environ Toxicol Chem 2016;35:1159 1171. Published 2015 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.« less

Changes in intense tropical cyclone activity for the western North Pacific during the last decades derived from a regional climate model simulation

NASA Astrophysics Data System (ADS)

Barcikowska, Monika; Feser, Frauke; Zhang, Wei; Mei, Wei

2017-11-01

An atmospheric regional climate model (CCLM) was employed to dynamically downscale atmospheric reanalyses (NCEP/NCAR 1, ERA 40) over the western North Pacific and South East Asia. This approach is used for the first time to reconstruct a tropical cyclone climatology, which extends beyond the satellite era and serves as an alternative data set for inhomogeneous observation-derived records (Best Track Data sets). The simulated TC climatology skillfully reproduces observations of the recent decades (1978-2010), including spatial patterns, frequency, lifetime, trends, variability on interannual and decadal time scales and their association with the large-scale circulation patterns. These skills, facilitated here with the spectral nudging method, seem to be a prerequisite to understand the factors determining spatio-temporal variability of TC activity over the western North Pacific. Long-term trends (1948-2011 and 1959-2001) in both simulations show a strong increase of intense tropical cyclone activity. This contrasts with pronounced multidecadal variations found in observations. The discrepancy may partly originate from temporal inhomogeneities in atmospheric reanalyses and Best Track Data, which affect both the model-based and observational-based trends. An adjustment, which removes the simulated upward trend, reduces the apparent discrepancy. Ultimately, our observational and modeling analysis suggests an important contribution of multi-decadal fluctuations in the TC activity during the last six decades. Nevertheless, due to the uncertainties associated with the inconsistencies and quality changes of those data sets, we call for special caution when reconstructing long-term TC statistics either from atmospheric reanalyses or Best Track Data.

Trends in diabetes-related visits to US EDs from 1997 to 2007.

PubMed

Menchine, Michael D; Wiechmann, Warren; Peters, Anne L; Arora, Sanjay

2012-06-01

The aims of the study were to describe temporal trends in the number, proportion, and per capita use of diabetes-related emergency department (ED) visits and to examine any racial/ethnic disparity in ED use for diabetes-related reasons. We analyzed the ED portion of the National Hospital Ambulatory Medical Care Survey from 1997 through 2007. Diabetes-related ED visits were identified by International Classification of Diseases, Ninth Revision codes. Descriptive statistics were developed. Weighted linear and logistic regression models were used to determine significance of temporal trends, and multivariate logistic regression was used to examine racial/ethnic disparities. A total of 20.2 million (1.69%; 95% confidence interval [CI], 1.59%-1.78%) ED visits were diabetes-related during the study period. We observed significant increases in the number and proportion of diabetes-related ED visits. Overall, there was a 5.6% relative annual increase in the proportion of ED visits that were diabetes-related during the study period. However, the per capita ED use among the population with diabetes did not change over time (P>.05 for trend). On multivariate analysis, black race (odds ratio, 1.8; 95% CI, 1.7-2.0), Hispanic ethnicity (odds ratio, 1.6; 95% CI, 1.4-1.8), and advancing age were associated with significantly higher odds of having a diabetes-related visit. Despite a marked increase in number and proportion of diabetes-related ED visits during the study period, the per capita use of ED services for diabetes-related visits among the diabetic population remained stable. Copyright © 2012 Elsevier Inc. All rights reserved.

Longitudinal measures of perfluoroalkyl substances (PFAS) in serum of Gullah African Americans in South Carolina: 2003-2013.

PubMed

Gribble, Matthew O; Bartell, Scott M; Kannan, Kurunthachalam; Wu, Qian; Fair, Patricia A; Kamen, Diane L

2015-11-01

Charleston Harbor has elevated concentrations of PFAS in dolphins, but local human exposure data are limited. We sought to describe PFAS serum concentrations' temporal trends among Gullah African American residents of coastal South Carolina. Longitudinal measures of PFAS in blood serum from a Gullah clinical sample, without lupus, were examined using spaghetti plots and visit-to-visit change scores (e.g., differences in concentrations between visits) among the 68 participants with repeated measures available. We also modeled population-level trends among the 71 participants with any data using proportionate percentile models, accounting for clustering through robust standard errors. In a post-hoc analysis we examined heterogeneity of temporal trends by age through mixed-effects models for the log-transformed PFAS compounds. Population concentrations of PFOS dropped approximately 9 (95% CI: 8, 10) percent each year over 2003-2013. This was concordant with individual PFOS trajectories (median PFOS change score -21.7 ng/g wet weight, interquartile range of PFOS change scores: -32.8, -14.9) and reports for other populations over this time period. Several other compounds including PFOA, PFHxS, and PFuNDA also showed a population-level decrease. However, examination of individual trajectories suggested substantial heterogeneity. Post-hoc analyses indicated that PFAS trajectories were heterogeneous by age. Many PFAS compounds are decreasing in a sample of Gullah African Americans from coastal South Carolina. There may be age differences in the elimination kinetics of PFASs. The possible role of age as a modifier of PFAS serum trends merits further research. Copyright © 2015 Elsevier Inc. All rights reserved.

The drinking water contamination crisis in Flint: Modeling temporal trends of lead level since returning to Detroit water system.

PubMed

Goovaerts, Pierre

2017-03-01

Since Flint returned to its pre-crisis source of drinking water close to 25,000 water samples have been collected and tested for lead and copper in >10,000 residences. This paper presents the first analysis and time trend modeling of lead data, providing new insights about the impact of this intervention. The analysis started with geocoding all water lead levels (WLL) measured during an 11-month period following the return to the Detroit water supply. Each data was allocated to the corresponding tax parcel unit and linked to secondary datasets, such as the composition of service lines, year built, or census tract poverty level. Only data collected on residential parcels within the City limits were used in the analysis. One key feature of Flint data is their collection through two different sampling initiatives: (i) voluntary or homeowner-driven sampling whereby concerned citizens decided to acquire a testing kit and conduct sampling on their own (non-sentinel sites), and (ii) State-controlled sampling where data were collected bi-weekly at selected sites after training of residents by technical teams (sentinel sites). Temporal trends modeled from these two datasets were found to be statistically different with fewer sentinel data exceeding WLL thresholds ranging from 10 to 50μg/L. Even after adjusting for housing characteristics the odds ratio (OR) of measuring WLL above 15μg/L at non-sentinel sites is significantly >1 (OR=1.480) and it increases with the threshold (OR=2.055 for 50μg/L). Joinpoint regression showed that the city-wide percentage of WLL data above 15μg/L displayed four successive trends since the return to Detroit Water System. Despite the recent improvement in water quality, the culprit for differences between sampling programs needs to be identified as it impacts exposure assessment and might influence whether there is compliance or not with the Lead and Copper Rule. Copyright © 2016 Elsevier B.V. All rights reserved.

Spatiotemporal variations of potential evapotranspiration and aridity index in relation to influencing factors over Southwest China during 1960-2013

NASA Astrophysics Data System (ADS)

Zhao, Yifei; Zou, Xinqing; Cao, Liguo; Yao, Yulong; Fu, Guanghe

2017-07-01

This study investigated the spatial-temporal patterns and trends of potential evapotranspiration (ET0) and aridity index (AI) over Southwest China during 1960-2013 based on daily temperature, precipitation, wind speed, sunshine duration, total solar radiation, and relative humidity data from 108 meteorological stations. The Penman-Monteith model, Mann-Kendall (M-K) test, moving t test, and Morlet wavelet method were used. The results indicated that ET0 and AI across the region displayed decreasing trends, but the former was significant. After 2000, regionally average trends in ET0 and AI increased rapidly, indicating that droughts increased over Southwest China in recent years. Spatially, the changes of ET0 and AI were dissimilar and not clustered, either. Temporally, both ET0 and AI displayed obvious abrupt change points over different timescales and that of AI was during the winter monsoon period. Significant periodic variations with periods of 27, 13, and 5 years were found in ET0, but only of 13 and 5 years existed in AI. Correlation analysis revealed that the sunshine duration and wind speed were the dominant factors affecting ET0 and that AI showed strong negative correlation with precipitation. The findings of this study enhance the understanding of the relationship between climate change and drought in Southwest China, while the mechanism controlling the variation in drought requires further study.

Outcomes in patients with community-acquired pneumonia admitted to the intensive care unit.

PubMed

Cavallazzi, Rodrigo; Wiemken, Timothy; Arnold, Forest W; Luna, Carlos M; Bordon, Jose; Kelley, Robert; Feldman, Charles; Chalmers, James D; Torres, Antoni; Ramirez, Julio

2015-06-01

Severe community-acquired pneumonia (CAP) portends a serious prognosis. The temporal trend in outcome of severe CAP is not well established. We evaluated the temporal trends in the outcomes of severe CAP. This is a secondary analysis of 800 patients with severe CAP enrolled in the Community-Acquired Pneumonia Organization International Cohort. Severe CAP was defined as CAP requiring admission to the intensive care unit. Only patients admitted to the ICU upon hospital admission were included in this study. We assessed the trend in outcomes of these patients during three time periods: Period I (June 2001 to April 2004), Period II (May 2004 to January 31 2008), and Period III (February 2008 to February 2013). After adjustment for other variables, mortality was higher for patients admitted during Period II compared with Period I (RR: 1.46; 95% CI: 1.002 to 2.14; P value = 0.049), and for Period III compared with Period I (RR: 1.70; 95% CI: 1.15 to 2.50; P value = 0.008). No significant difference in length of stay or time to clinical stability was found among the three periods. The mortality of patients with severe CAP increased over time in our study population. This finding has important health policy implications if confirmed by other studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

An investigation of trends in precious metal and copper content of RAM modules in WEEE: Implications for long term recycling potential.

PubMed

Charles, Rhys Gareth; Douglas, Peter; Hallin, Ingrid Liv; Matthews, Ian; Liversage, Gareth

2017-02-01

Precious metal (PM) and copper content of dynamic-RAM modules placed on the market during 1991-2008 has been analysed by AAS following comminution and acid digestion. Linear regression analysis of compositional data ordered according to sample chronology was used to identify historic temporal trends in module composition resulting from changes in manufacturing practices, and to project future trends for use in more accurate assessment of future recycling potential. DRAM was found to be 'high grade' waste with: stable levels of gold and silver over time; 80% reduction in palladium content during 1991-2008; and 0.23g/module/year increase in copper content with a 75% projected increase from 2008 by 2020. The accuracy of future recycling potential projections for WEEE using current methods based on static compositional data from current devices is questionable due to likely changes in future device composition. The impact on recycling potential projections of waste laptops, smart phones, cell phones and tablets arising in Europe in 2020 resulting from a 75% increase in copper content is considered against existing projections using static compositional data. The results highlight that failing to consider temporal variations in PM content may result in significant discrepancies between projections and future recycling potential. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Greening and browning of the Himalaya: Spatial patterns and the role of climatic change and human drivers.

PubMed

Mishra, Niti B; Mainali, Kumar P

2017-06-01

The reliable detection and attribution of changes in vegetation greenness is a prerequisite for the development of strategies for the sustainable management of ecosystems. We conducted a robust trend analysis on remote sensing derived vegetation index time-series matrices to detect significant changes in inter-annual vegetation productivity (greening versus browning) for the entire Himalaya, a biodiverse and ecologically sensitive yet understudied region. The spatial variability in trend was assessed considering elevation, 12 dominant land cover/use types and 10 ecoregions. To assess trend causation, at local scale, we compared multi-temporal imagery, and at regional scale, referenced ecological theories of mountain vegetation dynamics and ancillary literature. Overall, 17.56% of Himalayan vegetation (71,162km 2 ) exhibited significant trend (p<0.01) and majority (94%) showed positive trend (greening). Trend distribution showed strong elevational and ecoregion dependence as greening was most dominant at lower and middle elevations whereas majority of the browning occurred at higher elevation (>3800m), with eastern high Himalaya browning more dominantly than western high Himalaya. Land cover/use based categorization confirmed dominant greening of rainfed and irrigated agricultural areas, though cropped areas in western Himalaya contained higher proportion of greening areas. While rising atmospheric CO 2 concentration and nitrogen deposition are the most likely climatic causes of detected greening, success of sustainable forestry practices (community forestry in Nepal) along with increasing agricultural fertilization and irrigation facilities could be possible human drivers. Comparison of multi-temporal imagery enabled direct attribution of some browning areas to anthropogenic land change (dam, airport and tunnel construction). Our satellite detected browning of high altitude vegetation in eastern Himalaya confirm the findings of recent dendrochronology based studies which possibly resulted from reduced pre-monsoon moisture availability in recent decades. These results have significant implications for environmental management in the context of climate change and ecosystem dynamics in the Himalaya. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantifying the Temporal Inequality of Nutrient Loads with a Novel Metric

NASA Astrophysics Data System (ADS)

Gall, H. E.; Schultz, D.; Rao, P. S.; Jawitz, J. W.; Royer, M.

2015-12-01

Inequality is an emergent property of many complex systems. For a given series of stochastic events, some events generate a disproportionately large contribution to system responses compared to other events. In catchments, such responses cause streamflow and solute loads to exhibit strong temporal inequality, with the vast majority of discharge and solute loads exported during short periods of time during which high-flow events occur. These periods of time are commonly referred to as "hot moments". Although this temporal inequality is widely recognized, there is currently no uniform metric for assessing it. We used a novel application of Lorenz Inequality, a method commonly used in economics to quantify income inequality, to quantify the spatial and temporal inequality of streamflow and nutrient (nitrogen and phosphorus) loads exported to the Chesapeake Bay. Lorenz Inequality and the corresponding Gini Coefficient provide an analytical tool for quantifying inequality that can be applied at any temporal or spatial scale. The Gini coefficient (G) is a formal measure of inequality that varies from 0 to 1, with a value of 0 indicating perfect equality (i.e., fluxes and loads are constant in time) and 1 indicating perfect inequality (i.e., all of the discharge and solute loads are exported during one instant in time). Therefore, G is a simple yet powerful tool for providing insight into the temporal inequality of nutrient transport. We will present the results of our detailed analysis of streamflow and nutrient time series data collected since the early 1980's at 30 USGS gauging stations in the Chesapeake Bay watershed. The analysis is conducted at an annual time scale, enabling trends and patterns to be assessed both temporally (over time at each station) and spatially (for the same period of time across stations). The results of this analysis have the potential to create a transformative new framework for identifying "hot moments", improving our ability to temporally and spatially target implementation of best management practices to ultimately improve water quality in the Chesapeake Bay. This method also provides insight into the temporal scales at which hydrologic and biogeochemical variability dominate nutrient export dynamics.

Temporal trends of Cd, Cu, Hg, Pb and Zn in mussel (Mytilus galloprovincialis) from the Spanish North-Atlantic coast 1991-1999.

PubMed

Besada, V; Fumega, J; Vaamonde, A

2002-04-15

Temporal trends for heavy metals (Cd, Cu, Hg, Pb and Zn) in mussel (Mytilus galloprovincialis) from the Galician and Cantabrian areas in Spain, where samples were yearly collected from 1991 to 1999, are presented. This study was carried out by the Centro Oceanográfico de Vigo of the Instituto Español de Oceanografia (I.E.O.) as part of the Spanish contribution to the Joint Assessment and Monitoring Programme (JAMP) of the OSPAR Convention. The experimental work and subsequent statistical treatment, following OSPAR procedures and guidelines, are described. In order to carry out the statistical treatment of the data, median values of the different shell length classes were used for each contaminant, year and area. The Kendall T-b correlation coefficient was used with the purpose of demonstrating the existence of a downward significant temporal trend in the pollution levels, according to the advice of ICES Working Group on Statistical Aspects of Environmental Monitoring. A decrease of copper levels was detected in Vigo, Pontevedra and Arosa, of mercury in Pontevedra and A Coruña, of lead in Vigo, Pontevedra, A Coruña and Bilbao and of zinc in Pontevedra and A Coruña. However, a cadmium positive trend was registered at Ria de Vigo. No significant trends were detected in the other cases.

Atmospheric mechanisms governing the spatial and temporal variability of phenological phases in central Europe

NASA Astrophysics Data System (ADS)

Scheifinger, Helfried; Menzel, Annette; Koch, Elisabeth; Peter, Christian; Ahas, Rein

2002-11-01

A data set of 17 phenological phases from Germany, Austria, Switzerland and Slovenia spanning the time period from 1951 to 1998 has been made available for analysis together with a gridded temperature data set (1° × 1° grid) and the North Atlantic Oscillation (NAO) index time series. The disturbances of the westerlies constitute the main atmospheric source for the temporal variability of phenological events in Europe. The trend, the standard deviation and the discontinuity of the phenological time series at the end of the 1980s can, to a great extent, be explained by the NAO. A number of factors modulate the influence of the NAO in time and space. The seasonal northward shift of the westerlies overlaps with the sequence of phenological spring phases, thereby gradually reducing its influence on the temporal variability of phenological events with progression of spring (temporal loss of influence). This temporal process is reflected by a pronounced decrease in trend and standard deviation values and common variability with the NAO with increasing year-day. The reduced influence of the NAO with increasing distance from the Atlantic coast is not only apparent in studies based on the data set of the International Phenological Gardens, but also in the data set of this study with a smaller spatial extent (large-scale loss of influence). The common variance between phenological and NAO time series displays a discontinuous drop from the European Atlantic coast towards the Alps. On a local and regional scale, mountainous terrain reduces the influence of the large-scale atmospheric flow from the Atlantic via a proposed decoupling mechanism. Valleys in mountainous terrain have the inclination to harbour temperature inversions over extended periods of time during the cold season, which isolate the valley climate from the large-scale atmospheric flow at higher altitudes. Most phenological stations reside at valley bottoms and are thus largely decoupled in their temporal variability from the influence of the westerly flow regime (local-scale loss of influence). This study corroborates an increasing number of similar investigations that find that vegetation does react in a sensitive way to variations of its atmospheric environment across various temporal and spatial scales.

Comprehensive assessment of drought from 1960 to 2013 in China based on different perspectives

NASA Astrophysics Data System (ADS)

Lai, Wenli; Wang, Hongrui; Zhang, Jie

2017-10-01

Using daily and monthly precipitation data collected from 520 meteorological stations from 1960 to 2013, we compared a widely used drought index, the standardized precipitation index (SPI), with an extreme index, the maximum consecutive dry days index (CDD). Two other homogeneity test methods, namely the Gini coefficient (including both Total-Gini and Wet-Gini) and the precipitation concentration degree (PCD) were also applied to indirectly estimate extreme droughts. The changes in droughts determined using the SPI and the CDD exhibited similar spatial and temporal patterns throughout most parts of China, with the exception of Southwestern China. Comparison of the five indices indicated that Wet-Gini exhibited different or even opposite trends of drought across all of China. Finally, a trend analysis from 2000 to 2013 was applied to perform a regional empirical analysis of a classic extreme drought event in Southwestern China. All indices, except for Wet-Gini, indicated increasing drought risk.

Climatic Redistribution of Canada's Water Resources (CROCWR): An analysis of spatial and temporal hydrological trends and patterns in western Canada

NASA Astrophysics Data System (ADS)

Bawden, A. J.; Burn, D. H.; Prowse, T. D.

2012-12-01

Climate variability and change can have profound impacts on the hydrologic regime of a watershed. These effects are likely to be especially severe in regions particularly sensitive to changes in climate, such as the Canadian north, or when there are other stresses on the hydrologic regime, such as may occur when there are large withdrawals from, or land-use changes within, a watershed. A recent report of the Intergovernmental Panel on Climate Change (IPCC) stressed that future climate is likely to accelerate the hydrologic cycle and hence may affect water security in certain locations. For some regions, this will mean enhanced access to water resources, but because the effects will not be spatially uniform, other regions will experience reduced access. Understanding these patterns is critical for water managers and government agencies in western Canada - an area of highly contrasting hydroclimatic regimes and overlapping water-use and jurisdictional borders - as adapting to climate change may require reconsideration of inter-regional transfers and revised allocation of water resources to competing industrial sectors, including agriculture, hydroelectric production, and oil and gas. This research involves the detection and examination of spatial and temporal streamflow trends in western Canadian rivers as a response to changing climatic factors, including temperature, precipitation, snowmelt, and the synoptic patterns controlling these drivers. The study area, known as the CROCWR region, extends from the Pacific coast of British Columbia as far east as the Saskatchewan-Manitoba border and from the Canada-United States international border through a large portion of the Northwest Territories. This analysis examines hydrologic trends in monthly and annual streamflow for a collection of 34 hydrometric gauging stations believed to adequately represent the overall effects of climate variability and change on flows in western Canada by means of the Mann-Kendall non-parametric trend test. Large-scale spatial patterns are determined through examination of trends and contrasts between upper and lower reaches of individual sub-basins, as well as via analysis of streamflow redistributions within the CROCWR region as an entirety (i.e. north, south, east and/or west-moving patterns). Results are used to predict future implications of hydroclimatic variability and change on western Canada's water resources and recommend measures to be taken by water managers in response to these changes. This research is part of a larger hydroclimatic study that includes an analysis of the climatic drivers contributing to shifting flow regimes in western Canada as well as a study of the controlling synoptic patterns and teleconnections associated with changes in these driving forces.

Global trends in visibility: Implications for dust sources

USGS Publications Warehouse

Mahowald, N.M.; Ballantine, J.A.; Feddema, J.; Ramankutty, N.

2007-01-01

There is a large uncertainty in the relative roles of human land use, climate change and carbon dioxide fertilization in changing desert dust source strength over the past 100 years, and the overall sign of human impacts on dust is not known. We used visibility data from meteorological stations in dusty regions to assess the anthropogenic impact on long term trends in desert dust emissions. Visibility data are available at thousands of stations globally from 1900 to the present, but we focused on 359 stations with more than 30 years of data in regions where mineral aerosols play a dominant role in visibility observations. We evaluated the 1974 to 2003 time period because most of these stations have reliable records only during this time. We first evaluated the visibility data against AERONET aerosol optical depth data, and found that only in dusty regions are the two moderately correlated. Correlation coefficients between visibility derived variables and AERONET optical depths indicate a moderate correlation (???0.47), consistent with capturing about 20% of the variability in optical depths. Two visibility derived variables appear to compare the best with AERONET observations: the fraction of observations with visibility less than 5 km (VIS5) and the surface extinction (EXT). Regional trends show that in many dusty places, VIS5 and EXT are statistically significantly correlated with the palmer drought severity index (based on precipitation and temperature) or surface wind speeds, consistent with dust temporal variability being largely driven by meteorology. This is especially true for North African and Chinese dust sources, but less true in the Middle East, Australia or South America, where there are not consistent patterns in the correlations. Climate indices such as El Nino or the North Atlantic Oscillation are not correlated with visibility derived variables in this analysis. There are few stations where visibility measures are correlated with cultivation or grazing estimates on a temporal basis, although this may be a function of the very coarse temporal resolution of the land use datasets. On the other hand, spatial analysis of the visibility data suggests that natural topographic lows are not correlated with visibility, but land use is correlated at a moderate level. This analysis is consistent with land use being important in some regions, but meteorology driving interannual variability during 1974-2003.

Temporal trends of mercury in eggs of five sympatrically breeding seabird species in the Canadian Arctic.

PubMed

Braune, Birgit M; Gaston, Anthony J; Mallory, Mark L

2016-07-01

We compared temporal trends of total mercury (Hg) in eggs of five seabird species breeding at Prince Leopold Island in the Canadian high Arctic. As changes in trophic position over time have the potential to influence contaminant temporal trends, Hg concentrations were adjusted for trophic position (measured as δ(15)N). Adjusted Hg concentrations in eggs of thick-billed murres (Uria lomvia) and northern fulmars (Fulmarus glacialis) increased from 1975 to the 1990s, followed by a plateauing of levels from the 1990s to 2014. Trends of adjusted Hg concentrations in eggs of murres, fulmars, black guillemots (Cepphus grylle) and black-legged kittiwakes (Rissa tridactyla) had negative slopes between 1993 and 2013. Adjusted Hg concentrations in glaucous gull (Larus hyperboreus) eggs decreased by 50% from 1993 to 2003 before starting to increase again. Glaucous gull eggs had the highest Hg concentrations followed by black guillemot eggs, and black-legged kittiwake eggs had the lowest concentrations consistently in the five years compared between 1993 and 2013. Based on published toxicological thresholds for Hg in eggs, there is little concern for adverse reproductive effects due to Hg exposure in these birds, although the levels in glaucous gull eggs warrant future scrutiny given the increase in Hg concentrations observed in recent years. There is evidence that the Hg trends observed reflect changing anthropogenic Hg emissions. It remains unclear, however, to what extent exposure to Hg on the overwintering grounds influences the Hg trends observed in the seabird eggs at Prince Leopold Island. Future research should focus on determining the extent to which Hg exposure on the breeding grounds versus the overwintering areas contribute to the trends observed in the eggs. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Temporal trends in nitrate and selected pesticides in mid-atlantic ground water

USGS Publications Warehouse

Debrewer, L.M.; Ator, S.W.; Denver, J.M.

2008-01-01

Evaluating long-term temporal trends in regional ground-water quality is complicated by variable hydrogeologic conditions and typically slow flow, and such trends have rarely been directly measured. Ground-water samples were collected over near-decadal and annual intervals from unconfined aquifers in agricultural areas of the Mid-Atlantic region, including fractured carbonate rocks in the Great Valley, Potomac River Basin, and unconsolidated sediments on the Delmarva Peninsula. Concentrations of nitrate and selected pesticides and degradates were compared among sampling events and to apparent recharge dates. Observed temporal trends are related to changes in land use and chemical applications, and to hydrogeology and climate. Insignificant differences in nitrate concentrations in the Great Valley between 1993 and 2002 are consistent with relatively steady fertilizer application during respective recharge periods and are likely related to drought conditions in the later sampling period. Detecting trends in Great Valley ground water is complicated by long open boreholes characteristic of wells sampled in this setting which facilitate significant ground-water mixing. Decreasing atrazine and prometon concentrations, however, reflect reported changes in usage. On the Delmarva Peninsula between 1988 and 2001, median nitrate concentrations increased 2 mg per liter in aerobic ground water, reflecting increasing fertilizer applications. Correlations between selected pesticide compounds and apparent recharge date are similarly related to changing land use and chemical application. Observed trends in the two settings demonstrate the importance of considering hydrogeology and recharge date along with, changing land and chemical uses when interpreting trends in regional ground-water quality. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Daily MODIS Data Trends of Hurricane-Induced Forest Impact and Early Recovery

NASA Technical Reports Server (NTRS)

Ramsey, Elijah, III; Spruce, Joseph; Rangoonwala, Amina; Suzuoki, Yukihiro; Smoot, James; Gasser, Jerry; Bannister, Terri

2011-01-01

We studied the use of daily satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors to assess wetland forest damage and recovery from Hurricane Katrina (29 August 2005 landfall). Processed MODIS daily vegetation index (VI) trends were consistent with previously determined impact and recovery patterns provided by the "snapshot" 25 m Landsat Thematic Mapper optical and RADARSAT-1 synthetic aperture radar satellite data. Phenological trends showed high 2004 and 2005 pre-hurricane temporal correspondence within bottomland hardwood forest communities, except during spring green-up, and temporal dissimilarity between these hardwoods and nearby cypress-tupelo swamp forests (Taxodium distichum [baldcypress] and Nyssa aquatica [water tupelo]). MODIS VI trend analyses established that one year after impact, cypress-tupelo and lightly impacted hardwood forests had recovered to near prehurricane conditions. In contrast, canopy recovery lagged in the moderately and severely damaged hardwood forests, possibly reflecting regeneration of pre-hurricane species and stand-level replacement by invasive trees.

Earth's changing global atmospheric energy cycle in response to climate change

PubMed Central

Pan, Yefeng; Li, Liming; Jiang, Xun; Li, Gan; Zhang, Wentao; Wang, Xinyue; Ingersoll, Andrew P.

2017-01-01

The Lorenz energy cycle is widely used to investigate atmospheres and climates on planets. However, the long-term temporal variations of such an energy cycle have not yet been explored. Here we use three independent meteorological data sets from the modern satellite era, to examine the temporal characteristics of the Lorenz energy cycle of Earth's global atmosphere in response to climate change. The total mechanical energy of the global atmosphere basically remains constant with time, but the global-average eddy energies show significant positive trends. The spatial investigations suggest that these positive trends are concentrated in the Southern Hemisphere. Significant positive trends are also found in the conversion, generation and dissipation rates of energies. The positive trends in the dissipation rates of kinetic energies suggest that the efficiency of the global atmosphere as a heat engine increased during the modern satellite era. PMID:28117324

Multi-sensor studies of short-term interannual variations of aerosols

NASA Astrophysics Data System (ADS)

Leptoukh, G.; Zubko, V.

2009-04-01

In the present paper, we analyze in details the interannual variability of MODIS (Terra and Aqua) Aerosol Optical Depth (AOD) for years 2002 - 2008. The AOD anomaly maps of short-term trends exhibit interesting spatial variability with the AOD percent change per year reaching 10% or more in some contiguous areas ("hot" and "cold" spots). These numbers seem to be rather high to reflect the actual changes in aerosol emissions, thus prompting the following questions: Are these changes real, or some of these high trends are in fact artifacts of the analysis methods used? Can they be attributed to trends in aerosol sampling trends? Are they caused by changes in meteorological patterns affecting aerosol transport routs? Is there any relation of these changes to ENSO, NAO, and other known atmospheric cycles? Our analysis (still in progress) provides numerical answers and physical explanation to some of these questions. We investigate alternative methods for trend calculation and provide recommendations for a more robust AOD trend calculation. We correlate AOD spatial and temporal distributions with those of humidity, winds, seas surface temperature, and other geophysical parameters using remote sensing data from various space-based sensors, e.g., MODIS, AIRS, along with reanalysis data. We provide the most likely relation of AOD changes observed in some equatorial areas with the recent phase of ENSO. As a result, we identify regions where AOD short-term trends can be attributed to causes other than drastic changes in local aerosol emission and/or caused by the natural outbreaks (fires, volcano eruptions, etc.). We also identify regions with monotonic change in local pollution where the alternative explanations fail to provide different interpretation for the observed trends.

Estimating Water Levels with Google Earth Engine

NASA Astrophysics Data System (ADS)

Lucero, E.; Russo, T. A.; Zentner, M.; May, J.; Nguy-Robertson, A. L.

2016-12-01

Reservoirs serve multiple functions and are vital for storage, electricity generation, and flood control. For many areas, traditional ground-based reservoir measurements may not be available or data dissemination may be problematic. Consistent monitoring of reservoir levels in data-poor areas can be achieved through remote sensing, providing information to researchers and the international community. Estimates of trends and relative reservoir volume can be used to identify water supply vulnerability, anticipate low power generation, and predict flood risk. Image processing with automated cloud computing provides opportunities to study multiple geographic areas in near real-time. We demonstrate the prediction capability of a cloud environment for identifying water trends at reservoirs in the US, and then apply the method to data-poor areas in North Korea, Iran, Azerbaijan, Zambia, and India. The Google Earth Engine cloud platform hosts remote sensing data and can be used to automate reservoir level estimation with multispectral imagery. We combine automated cloud-based analysis from Landsat image classification to identify reservoir surface area trends and radar altimetry to identify reservoir level trends. The study estimates water level trends using three years of data from four domestic reservoirs to validate the remote sensing method, and five foreign reservoirs to demonstrate the method application. We report correlations between ground-based reservoir level measurements in the US and our remote sensing methods, and correlations between the cloud analysis and altimetry data for reservoirs in data-poor areas. The availability of regular satellite imagery and an automated, near real-time application method provides the necessary datasets for further temporal analysis, reservoir modeling, and flood forecasting. All statements of fact, analysis, or opinion are those of the author and do not reflect the official policy or position of the Department of Defense or any of its components or the U.S. Government

Past and present mercury accumulation in the Lake Baikal seal: Temporal trends, effects of life history, and toxicological implications.

PubMed

Poste, Amanda E; Pastukhov, Mikhail V; Braaten, Hans Fredrik Veiteberg; Ozersky, Ted; Moore, Marianne

2018-05-01

Despite global efforts to reduce anthropogenic mercury (Hg) emissions, the timescale and degree to which Hg concentrations in the environment and biota respond to decreased emissions remain challenging to assess or predict. In the present study we characterize long-term trends and life-history patterns in Hg accumulation and toxicological implications of Hg contamination for a freshwater seal from one of the world's largest lakes (Lake Baikal, Siberia, Russia) using contemporary tissues and archival teeth. Stable isotope analysis and Hg analyses of soft tissues (muscle, liver, kidney, blood, brain, heart) and teeth from 22 contemporary seals revealed rapid changes in diet and Hg accumulation in the first year of life with a stable diet and increase in tissue Hg throughout the rest of life. Although maternal transfer of Hg was an important source of Hg to seal pups, reproduction and lactation by female seals did not appear to result in sex-related differences in Hg concentrations or age-related accumulation in adult seals. Based on Hg analysis of archival teeth (n = 114) and reconstructed values for soft tissues, we also assessed temporal trends in seal Hg between the years 1960 and 2013. Seal Hg concentrations in hard (teeth) and soft (e.g., muscle, liver) tissues were highest in the 1960s and 1970s, followed by a decrease. The decline in seal Hg concentrations in recent decades was most likely driven by a reduction in Hg inputs to the lake, suggesting that global and regional efforts to reduce Hg emissions have been successful at reducing ecosystem and human health risks posed by Hg in Lake Baikal. Environ Toxicol Chem 2018;37:1476-1486. © 2018 SETAC. © 2018 SETAC.

Monotonic trends in spatio-temporal distribution and concentration of monsoon precipitation (1901-2002), West Bengal, India

NASA Astrophysics Data System (ADS)

Chatterjee, Soumendu; Khan, Ansar; Akbari, Hashem; Wang, Yupeng

2016-12-01

This paper intended to investigate spatio-temporal monotonic trend and shift in concentration of monsoon precipitation across West Bengal, India, by analysing the time series of monthly precipitation from 18 weather stations during the period from 1901 to 2002. In dealing with, the inhomogeneity in the precipitation series, RHtestsV4 software package is used to detect, and adjust for, multiple change points (shifts) that could exist in data series. Finally, the cumulative deviation test was applied at 5% significant level to check the homogeneity (presence of historic changes by cumulative deviations test). Afterward, non-parametric Mann-Kendall (MK) test and Theil-Sen estimator (TSE) was applied to detect of nature and slope of trends; and, Sequential Mann Kendall (SQMK) test was applied for detection of turning point and magnitude of change in trends. Prior to the application of statistical tests, the pre-whitening technique was used to eliminate the effect of autocorrelation in precipitation data series. Four indices- precipitation concentration index (PCI), precipitation concentration degree (PCD), precipitation concentration period (PCP) and fulcrum (centre of gravity) were used to detect precipitation concentration and the spatial pattern in it. The application of the above-mentioned procedures has shown very notable statewide monotonic trend for monsoon precipitation time series. Regional cluster analysis by SQMK found increasing precipitation in mountain and coastal regions in general, except during the non- monsoon seasons. The results show that higher PCI values were mainly observed in South Bengal, whereas lower PCI values were mostly detected in North Bengal. The PCI values are noticeably larger in places where both monsoon total precipitation and span of rainy season are lower. The results of PCP reveal that precipitation in Gangetic Bengal mostly occurs in summer (monsoon season), and the rainy season arrives earlier in North Bengal than South Bengal, whereas the results of PCD also indicate that the precipitation in North Bengal was more dispersed within a year than that in South Bengal. The concentration characteristic of precipitation could be detected by fulcrum analysis, and significant concentration over most of West Bengal was obvious within July month band. Precipitation trend observed in West Bengal is compared with that in Central India (CI) region and comparison of precipitation departure with Indian monsoon and Gangetic Bengal can be explained by forecasting ensemble.

Global trends in satellite-based emergency mapping

USGS Publications Warehouse

Voigt, Stefan; Giulio-Tonolo, Fabio; Lyons, Josh; Kučera, Jan; Jones, Brenda; Schneiderhan, Tobias; Platzeck, Gabriel; Kaku, Kazuya; Hazarika, Manzul Kumar; Czaran, Lorant; Li, Suju; Pedersen, Wendi; James, Godstime Kadiri; Proy, Catherine; Muthike, Denis Macharia; Bequignon, Jerome; Guha-Sapir, Debarati

2016-01-01

Over the past 15 years, scientists and disaster responders have increasingly used satellite-based Earth observations for global rapid assessment of disaster situations. We review global trends in satellite rapid response and emergency mapping from 2000 to 2014, analyzing more than 1000 incidents in which satellite monitoring was used for assessing major disaster situations. We provide a synthesis of spatial patterns and temporal trends in global satellite emergency mapping efforts and show that satellite-based emergency mapping is most intensively deployed in Asia and Europe and follows well the geographic, physical, and temporal distributions of global natural disasters. We present an outlook on the future use of Earth observation technology for disaster response and mitigation by putting past and current developments into context and perspective.

Is the economic crisis affecting birth outcome in Spain? Evaluation of temporal trend in underweight at birth (2003-2012).

PubMed

Varea, Carlos; Terán, José Manuel; Bernis, Cristina; Bogin, Barry; González-González, Antonio

2016-01-01

There is growing evidence of the impact of the current European economic crisis on health. In Spain, since 2008, there have been increasing levels of impoverishment and inequality, and important cuts in social services. The objective is to evaluate the impact of the economic crisis on underweight at birth in Spain. Trends in underweight at birth were examined between 2003 and 2012. Underweight at birth is defined as a singleton, term neonatal weight lesser than -2 SD from the median weight at birth for each sex estimated by the WHO Standard Growth Reference. Using data from the Statistical Bulletin of Childbirth, 2 933 485 live births born to Spanish mothers have been analysed. Descriptive analysis, seasonal decomposition analysis and crude and adjusted logistic regression including individual maternal and foetal variables as well as exogenous economic indicators have been performed. Results demonstrate a significant increase in the prevalence of underweight at birth from 2008. All maternal-foetal categories were affected, including those showing the lowest prevalence before the crisis. In the full adjusted logistic regression, year-on-year GDP per capita remains predictive on underweight at birth risk. Previous trends in maternal socio-demographic profiles and a direct impact of the crisis are discussed to explain the trends described.

Applying Metrological Techniques to Satellite Fundamental Climate Data Records

NASA Astrophysics Data System (ADS)

Woolliams, Emma R.; Mittaz, Jonathan PD; Merchant, Christopher J.; Hunt, Samuel E.; Harris, Peter M.

2018-02-01

Quantifying long-term environmental variability, including climatic trends, requires decadal-scale time series of observations. The reliability of such trend analysis depends on the long-term stability of the data record, and understanding the sources of uncertainty in historic, current and future sensors. We give a brief overview on how metrological techniques can be applied to historical satellite data sets. In particular we discuss the implications of error correlation at different spatial and temporal scales and the forms of such correlation and consider how uncertainty is propagated with partial correlation. We give a form of the Law of Propagation of Uncertainties that considers the propagation of uncertainties associated with common errors to give the covariance associated with Earth observations in different spectral channels.

Methods to Analyze Bone Regenerative Response to Different rhBMP-2 Doses in Rabbit Craniofacial Defects

DTIC Science & Technology

2014-02-28

sockets.6 The commercially available INFUSE system (Medtronic Spinal and Biologics, Memphis, TN), compris- ing an absorbable collagen sponge plus...a collagen sponge carrier) by Medtronics27 for bone healing in rabbits. Even the 25mg rhBMP-2 dose used showed significantly greater re- generated...visualization No 3D morphological analysis for small-animal modelsCan be repeated over course of healing for temporal trends Potential risk of X-ray

EMMMA: A web-based system for environmental mercury mapping, modeling, and analysis

USGS Publications Warehouse

Hearn,, Paul P.; Wente, Stephen P.; Donato, David I.; Aguinaldo, John J.

2006-01-01

tissue, atmospheric emissions and deposition, stream sediments, soils, and coal) and mercuryrelated data (mine locations); 2) Interactively view and access predictions of the National Descriptive Model of Mercury in Fish (NDMMF) at 4,976 sites and 6,829 sampling events (events are unique combinations of site and sampling date) across the United States; and 3) Use interactive mapping and graphing capabilities to visualize spatial and temporal trends and study relationships between mercury and other variables.

Mapping mountain pine beetle mortality through growth trend analysis of time-series landsat data

USGS Publications Warehouse

Liang, Lu; Chen, Yanlei; Hawbaker, Todd J.; Zhu, Zhi-Liang; Gong, Peng

2014-01-01

Disturbances are key processes in the carbon cycle of forests and other ecosystems. In recent decades, mountain pine beetle (MPB; Dendroctonus ponderosae) outbreaks have become more frequent and extensive in western North America. Remote sensing has the ability to fill the data gaps of long-term infestation monitoring, but the elimination of observational noise and attributing changes quantitatively are two main challenges in its effective application. Here, we present a forest growth trend analysis method that integrates Landsat temporal trajectories and decision tree techniques to derive annual forest disturbance maps over an 11-year period. The temporal trajectory component successfully captures the disturbance events as represented by spectral segments, whereas decision tree modeling efficiently recognizes and attributes events based upon the characteristics of the segments. Validated against a point set sampled across a gradient of MPB mortality, 86.74% to 94.00% overall accuracy was achieved with small variability in accuracy among years. In contrast, the overall accuracies of single-date classifications ranged from 37.20% to 75.20% and only become comparable with our approach when the training sample size was increased at least four-fold. This demonstrates that the advantages of this time series work flow exist in its small training sample size requirement. The easily understandable, interpretable and modifiable characteristics of our approach suggest that it could be applicable to other ecoregions.

Temporal trends in adolescents’ self-reported psychosomatic health complaints from 1980-2016: A systematic review and meta-analysis

PubMed Central

Potrebny, Thomas; Wiium, Nora; Lundegård, Margrethe Moss-Iversen

2017-01-01

Objective There is increasing concern that mental health may be deteriorating in recent generations of adolescents. It is unclear whether this is the case for self-reported psychosomatic health complaints (PSHC). Method We conducted a systematic review and meta-analysis of published primary studies on PSHC in the general adolescent population over time. The primary databases were MEDLINE, Embase and PsycINFO, which were searched from inception to November 2016. Studies were included if they involved an observational design, presented self-reported data from participants aged 10–19 years and included data from at least two time points, five years apart. Inclusion and study quality were assessed by two independent reviewers. Results Twenty-one studies were included; 18 reported trends on the prevalence of PSHC in a single country, while three studies reported on multiple countries. In total, over seven million adolescents from 36 countries in Europe, North America, Israel and New Zealand were represented, covering the period 1982–2013. In the descriptive analysis, 10 studies indicated a trend of increasing PSHC, eight showed a stable trend and three showed a decreasing trend at certain points in time. The results from the meta-analysis showed a mean odds ratio (OR) of 1.04 (K = 139, 95% CI 1.01–1.08) for PSHC from 1982 to 2013, thus indicating a minor increase in general. In the subgroup analysis, this minor increase was observed mainly between the 1980s and 2000s, while the trend appeared to be more stable between the 2000s and 2010s. Some differences were also found between multinational subregions. Findings from subgroup analysis, however, only supported a significant increasing trend in Northern Europe. Conclusion There may have been a minor increasing trend in adolescent self-rated PSHC between the 1980 and 2000s, but has become more stable since the 2010s, from a multinational perspective. Northern Europe was the only region to show a clearly significant minor increasing trend, without being the region with the highest total prevalence of PSHC at the present time. The discrepant trends regarding PSHC between regions and the reliance on self-reported data may reflect true changes in the occurrence of PSHC in the adolescent population. However, they may also reflect changes in how adolescents perceive and report health complaints. Other PROSPERO registration 2016: CRD42016048300. PMID:29182644

Beyond linear methods of data analysis: time series analysis and its applications in renal research.

PubMed

Gupta, Ashwani K; Udrea, Andreea

2013-01-01

Analysis of temporal trends in medicine is needed to understand normal physiology and to study the evolution of disease processes. It is also useful for monitoring response to drugs and interventions, and for accountability and tracking of health care resources. In this review, we discuss what makes time series analysis unique for the purposes of renal research and its limitations. We also introduce nonlinear time series analysis methods and provide examples where these have advantages over linear methods. We review areas where these computational methods have found applications in nephrology ranging from basic physiology to health services research. Some examples include noninvasive assessment of autonomic function in patients with chronic kidney disease, dialysis-dependent renal failure and renal transplantation. Time series models and analysis methods have been utilized in the characterization of mechanisms of renal autoregulation and to identify the interaction between different rhythms of nephron pressure flow regulation. They have also been used in the study of trends in health care delivery. Time series are everywhere in nephrology and analyzing them can lead to valuable knowledge discovery. The study of time trends of vital signs, laboratory parameters and the health status of patients is inherent to our everyday clinical practice, yet formal models and methods for time series analysis are not fully utilized. With this review, we hope to familiarize the reader with these techniques in order to assist in their proper use where appropriate.

Temporal changes in native-exotic richness correlations during early post-fire succession

Treesearch

Qinfeng Guo

2017-01-01

The relationship between native and exotic richness has mostly been studied with respect to space (i.e., positive at larger scales, but negative or more variable at smaller scales) and its temporal patterns have rarely been investigated. Although some studies have monitored the temporal trends of both native and exotic richness, how these two groups of species might be...

ESTIMATES OF THE ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN SPECIES: CLEAN AIR STATUS AND TRENDS NETWORK. 1990 THROUGH 2000

EPA Science Inventory

The Clean Air Status and Trends Network (CASTNet) was established by EPA in response to the requirements of the 1990 Clean Air Act Amendments. To satisfy these requirements CASTNet was designed to assess and report on geographic patterns and long-term, temporal trends in ambient ...

Temporal Methods to Detect Content-Based Anomalies in Social Media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skryzalin, Jacek; Field, Jr., Richard; Fisher, Andrew N.

Here, we develop a method for time-dependent topic tracking and meme trending in social media. Our objective is to identify time periods whose content differs signifcantly from normal, and we utilize two techniques to do so. The first is an information-theoretic analysis of the distributions of terms emitted during different periods of time. In the second, we cluster documents from each time period and analyze the tightness of each clustering. We also discuss a method of combining the scores created by each technique, and we provide ample empirical analysis of our methodology on various Twitter datasets.

Spatial Analysis of the Human Immunodeficiency Virus Epidemic among Men Who Have Sex with Men in China, 2006-2015.

PubMed

Qin, Qianqian; Guo, Wei; Tang, Weiming; Mahapatra, Tanmay; Wang, Liyan; Zhang, Nanci; Ding, Zhengwei; Cai, Chang; Cui, Yan; Sun, Jiangping

2017-04-01

Studies have shown a recent upsurge in human immunodeficiency virus (HIV) burden among men who have sex with men (MSM) in China, especially in urban areas. For intervention planning and resource allocation, spatial analyses of HIV/AIDS case-clusters were required to identify epidemic foci and trends among MSM in China. Information regarding MSM recorded as HIV/AIDS cases during 2006-2015 were extracted from the National Case Reporting System. Demographic trends were determined through Cochran-Armitage trend tests. Distribution of case-clusters was examined using spatial autocorrelation. Spatial-temporal scan was used to detect disease clustering. Spatial correlations between cases and socioenvironmental factors were determined by spatial regression. Between 2006 and 2015, in China, 120 371 HIV/AIDS cases were identified among MSM. Newly identified HIV/AIDS cases among self-reported MSM increased from 487 cases in 2006 to >30 000 cases in 2015. Among those HIV/AIDS cases recorded during 2006-2015, 47.0% were 20-29 years old and 24.9% were aged 30-39 years. Based on clusters of HIV/AIDS cases identified through spatial analysis, the epidemic was concentrated among MSM in large cities. Spatial-temporal clusters contained municipalities, provincial capitals, and main cities such as Beijing, Shanghai, Chongqing, Chengdu, and Guangzhou. Spatial regression analysis showed that sociodemographic indicators such as population density, per capita gross domestic product, and number of county-level medical institutions had statistically significant positive correlations with HIV/AIDS among MSM. Assorted spatial analyses revealed an increasingly concentrated HIV epidemic among young MSM in Chinese cities, calling for targeted health education and intensive interventions at an early age. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Mapping the Dynamics of Surface Water Extent 1999-2015 with Landsat 5, 7, and 8 Archives

NASA Astrophysics Data System (ADS)

Pickens, A. H.; Hansen, M.; Hancher, M.; Potapov, P.

2016-12-01

Surface water extent fluctuates through both seasons and years due to changes in climatic conditions and human extraction and impoundments. This study maps the presence of surface water every month since January 1999, evaluates the detection reliability, visualizes the trends, and explores future applications. The Global Land Analysis and Discovery group at the University of Maryland developed a 30-m mask of persistent water during the growing seasons of 2000-2012 in conjunction with the Global Forest Change product published by Hansen et al. in 2013. A total of 654,178 Landsat 7 scenes were used for the study. Persistent water was defined as all pixels with water classified in more than 50% of observations over the study period. We validated this mask by stratifying and comparing against a random sample of 135 RapidEye, single-date images at 5-m resolution. It was found to have estimated user's and producer's accuracies of 94% and 88%, respectively. This estimated error is due primarily to temporal differences, such as dam construction, and to mixed water-land pixels along water body edges and narrow rivers. In order to investigate temporal extent dynamics, we expanded our analysis of surface water to classify every Landsat 5, 7, and 8 scene since 1999, augmented with elevation data from SRTM and ASTER, via a series of decision trees applied using Google Earth Engine. The water and land observations are aggregated per each month of each year. We developed a model to visualize the dynamic trend in surface water presence since 1999, either per month or annually as shown below. This model can be used directly to assess the seasonal and inter-annual trends globally or regionally, or the raw monthly counts can be used for more intensive hydrological analysis and as inputs for other related studies such as wetland mapping.

Timed Up and Go test, atrophy of medial temporal areas and cognitive functions in community-dwelling older adults with normal cognition and mild cognitive impairment.

PubMed

Kose, Yujiro; Ikenaga, Masahiro; Yamada, Yosuke; Morimura, Kazuhiro; Takeda, Noriko; Ouma, Shinji; Tsuboi, Yoshio; Yamada, Tatsuo; Kimura, Misaka; Kiyonaga, Akira; Higaki, Yasuki; Tanaka, Hiroaki

2016-12-01

This study aimed to ascertain if performance on the Timed Up and Go (TUG) test is associated with indicators of brain volume and cognitive functions among community-dwelling older adults with normal cognition or mild cognitive impairment. Participants were 80 community-dwelling older adults aged 65-89years (44 men, 36 women), including 20 with mild cognitive impairment. Participants completed the TUG and a battery of cognitive assessments, including the Mini-Mental State Examination (MMSE), the Logical Memory I and II (LM-I, LM-II) subtests of the Wechsler Memory Scale-Revised; and the Trail Making Test A and B (TMT-A, TMT-B). Bilateral, right- and left-side medial temporal area atrophy as well as whole gray and white matter indices were determined with the Voxel-based Specific Regional Analysis System for Alzheimer's Disease. We divided participants into three groups based on TUG performance: "better" (≤6.9s); "normal" (7-10s); and "poor" (≥10.1s). Worse TMT-A and TMT-B performance showed significant independent associations with worse TUG performance (P<0.05, P<0.01 for trend, respectively). After adjusting for covariates, severe atrophy of bilateral, right-, and left-side medial temporal areas were significantly independently associated with worse TUG performance (P<0.05 for trend). However, no significant associations were found between MMSE, LM-I, LM-II, whole gray and white matter indices, and TUG performance. Worse TUG performance is related to poor performance on TMT-A and TMT-B, and is independently associated with severe medial temporal area atrophy in community-dwelling older adults. Copyright © 2016 Elsevier Inc. All rights reserved.

Temporal and diurnal analysis of trace elements in the Cryospheric water at remote Laohugou basin in northeast Tibetan Plateau.

PubMed

Dong, Zhiwen; Kang, Shichang; Qin, Dahe; Qin, Xiang; Yan, Fangping; Du, Wentao; Wei, Ting

2017-03-01

An evaluation of glacial meltwater chemistry is needed under recent dramatic glacier melting when water resources might be significantly impacted. This study investigated trace elements variation in the meltwater stream, and its related aquatic environmental information, at the Laohugou (LHG) glacier basin (4260 m a.s.l.) at a remote location in northeast Tibetan Plateau. We focused on the spatial, temporal and diurnal change of trace elements during the glacier ablation period. Results showed evident elements spatial difference on the glacier surface meltwater, as most of the elements showed increased concentration at the terminus compared to higher elevations sites. Dominant elements in the meltwater were Ba, Sr and Cr, whereas elements with high enrichment factors (EFs) were Sb, Ni, Mo and Zn. Temporal change of some trace elements concentration (e.g. Sc, Cu, and Rb) indicated increasing trend with accelerated snow-ice melting, whereas others (e.g. Ni, Zn, and Pb) showed decreasing trend. We find that, trace elements showed evident diurnal change and a peak value of concentration was observed each day at about 15:00-17:00, and the diurnal change was influenced by runoff level and pH. Moreover, EFs calculations revealed that heavy metals were partially originated from regional anthropogenic sources. Overall, the accelerated diurnal and temporal snow-ice melting (with high runoff level) were correlated to increased elemental concentration, pH, EC and elemental change mode, and thus this work is of great importance for evaluating the impacts of accelerated glacier melting to meltwater chemistry and downstream ecosystem in the northeast Tibetan Plateau. Copyright © 2016 Elsevier Ltd. All rights reserved.

Determining hydroclimatic extreme events over the south-central Andes

NASA Astrophysics Data System (ADS)

RamezaniZiarani, Maryam; Bookhagen, Bodo; Schmidt, Torsten; Wickert, Jens; de la Torre, Alejandro; Volkholz, Jan

2017-04-01

The south-central Andes in NW Argentina are characterized by a strong rainfall asymmetry. In the east-west direction exists one of the steepest rainfall gradients on Earth, resulting from the large topographic differences in this region. In addition, in the north-south direction the rainfall intensity varies as the climatic regime shifts from the tropical central Andes to the subtropical south-central Andes. In this study, we investigate hydroclimatic extreme events over the south-central Andes using ERA-Interim reanalysis data of the ECMWF (European Centre for Medium-Range Weather Forecasts), the high resolution regional climate model (COSMO-CLM) data and TRMM (Tropical Rainfall Measuring Mission) data. We divide the area in three different study regions based on elevation: The high-elevation Altiplano-Puna plateau, an intermediate area characterized by intramontane basins, and the foreland area. We analyze the correlations between climatic variables, such as specific humidity, zonal wind component, meridional wind component and extreme rainfall events in all three domains. The results show that there is a high positive temporal correlation between extreme rainfall events (90th and 99th percentile rainfall) and extreme specific humidity events (90th and 99th percentile specific humidity). In addition, the temporal variations analysis represents a trend of increasing specific humidity with time during time period (1994-2013) over the Altiplano-Puna plateau which is in agreement with rainfall trend. Regarding zonal winds, our results indicate that 99th percentile rainfall events over the Altiplano-Puna plateau coincide temporally with strong easterly winds from intermountain and foreland regions in the east. In addition, the results regarding the meridional wind component represent strong northerly winds in the foreland region coincide temporally with 99th percentile rainfall over the Altiplano-Puna plateau.

Continuous non-marine inputs of per- and polyfluoroalkyl substances to the High Arctic: a multi-decadal temporal record

NASA Astrophysics Data System (ADS)

Pickard, Heidi M.; Criscitiello, Alison S.; Spencer, Christine; Sharp, Martin J.; Muir, Derek C. G.; De Silva, Amila O.; Young, Cora J.

2018-04-01

Perfluoroalkyl acids (PFAAs) are persistent, in some cases, bioaccumulative compounds found ubiquitously within the environment. They can be formed from the atmospheric oxidation of volatile precursor compounds and undergo long-range transport (LRT) through the atmosphere and ocean to remote locations. Ice caps preserve a temporal record of PFAA deposition making them useful in studying the atmospheric trends in LRT of PFAAs in polar or mountainous regions, as well as in understanding major pollutant sources and production changes over time. A 15 m ice core representing 38 years of deposition (1977-2015) was collected from the Devon Ice Cap in Nunavut, providing us with the first multi-decadal temporal ice record in PFAA deposition to the Arctic. Ice core samples were concentrated using solid phase extraction and analyzed by liquid and ion chromatography methods. Both perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) were detected in the samples, with fluxes ranging from < LOD to 141 ng m-2 yr-1. Our results demonstrate that the PFCAs and perfluorooctane sulfonate (PFOS) have continuous and increasing deposition on the Devon Ice Cap, despite recent North American and international regulations and phase-outs. We propose that this is the result of on-going manufacture, use and emissions of these compounds, their precursors and other newly unidentified compounds in regions outside of North America. By modelling air mass transport densities, and comparing temporal trends in deposition with production changes of possible sources, we find that Eurasian sources, particularly from Continental Asia, are large contributors to the global pollutants impacting the Devon Ice Cap. Comparison of PFAAs to their precursors and correlations of PFCA pairs showed that deposition of PFAAs is dominated by atmospheric formation from volatile precursor sources. Major ion analysis confirmed that marine aerosol inputs are unimportant to the long-range transport mechanisms of these compounds. Assessments of deposition, homologue profiles, ion tracers, air mass transport models, and production and regulation trends allow us to characterize the PFAA depositional profile on the Devon Ice Cap and further understand the LRT mechanisms of these persistent pollutants.

Plio-Quaternary stress states in NE Iran: Kopeh Dagh and Allah Dagh-Binalud mountain ranges

NASA Astrophysics Data System (ADS)

Shabanian, Esmaeil; Bellier, Olivier; Abbassi, Mohammad R.; Siame, Lionel; Farbod, Yassaman

2010-01-01

NE Iran, including the Kopeh Dagh and Allah Dagh-Binalud deformation domains, comprises the northeastern boundary of the Arabia-Eurasia collision zone. This study focuses on the evolution of the Plio-Quaternary tectonic regimes of northeast Iran. We present evidence for drastic temporal changes in the stress state by inversion of both geologically and seismically determined fault slip vectors. The inversions of fault kinematics data reveal distinct temporal changes in states of stress during the Plio-Quaternary (since ˜ 5 Ma). The paleostress state is characterized by a regional transpressional tectonic regime with a mean N140 ± 10°E trending horizontal maximum stress axis ( σ1). The youngest (modern) state of stress shows two distinct strike-slip and compressional tectonic regimes with a regional mean of N030 ± 15°E trending horizontal σ1. The change from the paleostress to modern stress states has occurred through an intermediate stress field characterized by a mean regional N trending σ1. The inversion analysis of earthquake focal mechanisms reveals a homogeneous, transpressional tectonic regime with a regional N023 ± 5°E trending σ1. The modern stress state, deduced from the youngest fault kinematics data, is in close agreement with the present-day stress state given by the inversions of earthquake focal mechanisms. According to our data and the deduced results, in northeast Iran, the Arabia-Eurasia convergence is taken up by strike-slip faulting along NE trending left-lateral and NNW trending right-lateral faults, as well as reverse to oblique-slip reverse faulting along NW trending faults. Such a structural assemblage is involved in a mechanically compatible and homogeneous modern stress field. This implies that no strain and/or stress partitioning or systematic block rotations have occurred in the Kopeh Dagh and Allah Dagh-Binalud deformation domains. The Plio-Quaternary stress changes documented in this paper call into question the extrapolation of the present-day seismic and GPS-derived deformation rates over geological time intervals encompassing tens of millions of years.

Water-quality conditions at selected landfills in Mecklenburg County, North Carolina, 1986-92

USGS Publications Warehouse

Ferrell, G.M.; Smith, D.G.

1995-01-01

Water-quality conditions at five municipal landfills in Mecklenburg County, North Carolina, were studied during 1986-92. Analytical results of water samples from monitoring wells and streams at and near the landfills were used to evaluate effects of leachate on surface and ground water. Ground-water levels at monitoring wells were used to determine directions of ground-water flow at the landfills. Data from previous studies were used for analysis of temporal trends in selected water-quality properties and chemical constituents. Effects of leachate, such as large biochemical- and chemical-oxygen demands, generally were evident in small streams originating within the landfills, whereas effects of leachate generally were not evident in most of the larger streams. In larger streams, surface-water quality upstream and downstream from most of the landfills was similar. However, the chemical quality of water in Irwin Creek appears to have been affected by the Statesville Road landfill. Concentrations of several constituents indicative of leachate were larger in samples collected from Irwin Creek downstream from the Statesville Road landfill than in samples collected from Irwin Creek upstream from the landfill. The effect of leachate on ground-water quality generally was largest in water from wells adjacent to waste-disposal cells. Concentrations of most constituents considered indicative of leachate generally were smaller with increasing distance from waste-disposal cells. Water samples from offsite wells generally indicated no effect or very small effects of leachate. Action levels designated by the Mecklenburg County Engineering Department and maximum contaminant levels established by the U.S. Environmental Protection Agency were exceeded in some samples from the landfills. Ground-water samples exceeded action levels and maximum contaminant levels more commonly than surface-water samples. Iron and manganese were the constituents that most commonly exceeded action levels in water samples from the landfills. Synthetic organic compounds were detected more commonly and in larger concentrations in ground-water samples than in surface-water samples. Concentrations of synthetic organic compounds detected in water samples from monitoring sites at the landfills generally were much less than maximum contaminant levels. However, concentrations of some chlorinated organic compounds exceeded maximum contaminant levels in samples from several monitoring wells at the Harrisburg Road and York Road landfills. Trend analysis indicated statistically significant temporal changes in concentrations of selected water-quality constituents and properties at some of the monitoring sites. Trends detected for the Holbrooks Road and Statesville Road landfills generally indicated an improvement in water quality and a decrease in effects of leachate at most monitoring sites at these landfills from 1979 to 1992. Water-quality trends detected for monitoring sites at the Harrisburg Road and York Road landfills, the largest landfills in the study, differed in magnitude and direction. Upward trends generally were detected for sites near recently closed waste-disposal cells, whereas downward trends generally were detected for sites near older waste-disposal cells. Temporal trends in water quality generally reflected changes in degradation processes associated with the aging of landfill wastes.

Trends in the Use of Percutaneous Ventricular Assist Devices: Analysis of National Inpatient Sample Data, 2007 Through 2012

PubMed Central

Khera, Rohan; Cram, Peter; Lu, Xin; Vyas, Ankur; Gerke, Alicia; Rosenthal, Gary E.; Horwitz, Phillip A.; Girotra, Saket

2016-01-01

Importance Percutaneous ventricular assist devices (PVADs) provide robust hemodynamic support compared with intra-aortic balloon pumps (IABPs), but clinical use patterns are unknown. Objective To examine contemporary patterns in PVAD use in the United States and compare them with use of IABPs. Design, Setting, and Participants Retrospective study of adults older than 18 years who received a PVAD or IABP while hospitalized in the United States (2007-2012). Main Outcomes and Measures Temporal trends in utilization, patient and hospital characteristics, in-hospital mortality, and cost of PVAD use compared with IABP. Results During 2007 through 2012, utilization of PVADs increased 30-fold (4.6 per million discharges in 2007 to 138 per million discharges in 2012; P for trend < .001) while utilization of IABPs decreased from 1738 per million discharges in 2008 to 1608 per million discharges in 2012 (P for trend = .02). In 2007, an estimated 72 hospitals used PVADs, increasing to 477 in 2011 (P for trend < .001). The number of hospitals with an annual volume of 10 or more PVAD procedures per year increased from 0 in 2007 to 102 in 2011 (21.4% ofPVAD-using hospitals; P for trend < .001). Among PVAD recipients, 67.3% had a diagnosis of cardiogenic shock or acute myocardial infarction (AMI). There was a temporal increase in the use of PVADs in older patients and patients with AMI, hypertension, diabetes mellitus, and chronic kidney disease (P for trend < .001 for all). Overall, mortality in PVAD recipients was 28.8%, and mean (SE) hospitalization cost was $85 580 ($4165); both were significantly higher in PVAD recipients with cardiogenic shock (mortality, 47.5%; mean [SE] cost, $113 695 [$6260]; P < .001 for both). The PVAD recipients were less likely than IABP recipients to have cardiogenic shock (34.3% vs 41.2%; P = .001), AMI (48.0% vs68.6%; P < .001), and undergo coronary artery bypass graft surgery (6.2% vs 43.2%; P < .001), but more likely to undergo percutaneous coronary intervention (70.9% vs 40.4%; P < .001). In propensity-matched analysis, PVADs were associated with higher mortality compared with IABP (odds ratio, 1.23 [95% CI, 1.06-1.43]; P = .007). Conclusions and Relevance There has been a substantial increase in the use of PVADs in recent years with an accompanying decrease in the use of IABPs. Given the high mortality, associated cost, and uncertain evidence for a clear benefit, randomized clinical trials are needed to determine whether use of PVADs leads to improved patient outcomes. PMID:25822170

The effect of length and starting year on trend analyses of temperatures in Spanish mainland (1951-2010). A general approach (I)

NASA Astrophysics Data System (ADS)

Gonzalez Hidalgo, Jose Carlos; Peña Angulo, Dhais; Salinas Solé, Celia; Jiménez Castañeda, Azucena; Brunetti, Michele

2017-04-01

One of the most interesting issues in climate analyses of trend is the comparison between different results. This is a difficult task not only because of different spatial density of information, or data format (raster or station), but also because they usually analyze different temporal periods, sometimes differing only in few years, and trend of time (climate) variables can vary dramatically accordingly length of period and starting year (Lüdecke et al., 2011). In this poster we present the global frame of an approach that during the last years has attracted the attention of some researchers: the moving windows analyze. Basically it consists in calculate the trends for all the possible period, combining length and starting year in any given series of climate variables. The analysis obviously only can be applied to one series of data (i.e. one station), and the results are usually presented in triangular diagrams. This approach has been applied to regional, national or global series both to temperature and precipitation (Brunetti et al., 2006; Liebmann et al., 2010; González.Hidalgo et al. 2010, 2016, between others). The spatial differences in the behavior of temperatures and precipitation during the last year has been noticed in many research, particularly when high density of stations has been used, so the question is how to use this approach in dozens, hundreds or thousands of stations? We present in this poster example of graphical analyses of moving windows, how to read the graphs, the possibility that this analyses offers, etc. In a sequence of posters the analyze is applied to a high-resolution grid of monthly temperatures of Spanish mainland, MOTEDAS dataset (1951-2010), at season and monthly temporal scale (see Winter-II, Spring-III, Summer-IV and Autumn-V Posters). To apply the approach we have used an ergodic transformations from time (each temporal series) to space (all the series in the same period), i.e. we present the results of season and monthly mean values of Tmax and Tmin trends by showing a collection of maps accordingly changes in period length and starting year. In the sequence of seasons (see Poster II-III-IV and V), we have selected particularly a decreasing length period from triangular diagram, i.e. from 1951-2010 until 1991- 2010 (the hypotenuse of graphical triangle), thus, we analyze all the possible trends in periods between 60-years and 20-years (considering that 20 years represent a minimum period for detect any climate signal).

Multi-temporal analysis of forest fire risk driven by environmental and socio-economic change in the Republic of Korea

NASA Astrophysics Data System (ADS)

Kim, S. J.; Lim, C. H.; Kim, G. S.; Lee, W. K.

2017-12-01

Analysis of forest fire risk is important in disaster risk reduction (DRR) since it provides a way to manage forest fires. Climate and socio-economic factors are important in the cause of forest fires, and the role of the socio-economic factors in prevention and preparedness of forest fires is increasing. As most of the forest fires in the Republic of Korea are highly related to human activities, both environmental factors and socio-economic factors were considered into the analysis of forest fire risk. In this study, the Maximum Entropy (MaxEnt) model was used to predict the potential geographical distribution and probability of forest fire occurrence spatially and temporally from 1980s to the 2010s in the Republic of Korea by multi-temporal analysis and analyze the relationship between forest fires and the factors. As a result of the risk analysis, there was an overall increasing trend in forest fire risk from the 1980s to the 2000s, and socio-economic factors were highly correlated with the occurrence of forest fires. The study demonstrates that the socio-economic factors considered as human activities can increase the occurrence of forest fires. The result implies that managing human activities are significant to prevent forest fire occurrence. In addition, timely forest fire prevention and control is necessary as drought index such as Standardized Precipitation Index (SPI) also affected forest fires.

Temporal trends of postinjury multiple-organ failure: Still resource intensive, morbid, and lethal

PubMed Central

Sauaia, Angela; Moore, Ernest E.; Johnson, Jeffrey L.; Chin, Theresa L.; Banerjee, Anirban; Sperry, Jason L.; Maier, Ronald V.; Burlew, C. Cothren

2014-01-01

BACKGROUND While the incidence of postinjury multiple-organ failure (MOF) has declined during the past decade, temporal trends of its morbidity, mortality, presentation patterns, and health care resources use have been inconsistent. The purpose of this study was to describe the evolving epidemiology of postinjury MOF from 2003 to 2010 in multiple trauma centers sharing standard treatment protocols. METHODS “Inflammation and Host Response to Injury Collaborative Program” institutions that enrolled more than 20 eligible patients per biennial during the 2003 to 2010 study period were included. The patients were aged 16 years to 90 years, sustained blunt torso trauma with hemorrhagic shock (systolic blood pressure < 90 mm Hg, base deficit ≥ 6 mEq/L, blood transfusion within the first 12 hours), but without severe head injury (motor Glasgow Coma Scale [GCS] score < 4). MOF temporal trends (Denver MOF score > 3) were adjusted for admission risk factors (age, sex, body max index, Injury Severity Score [ISS], systolic blood pressure, and base deficit) using survival analysis. RESULTS A total of 1,643 patients from four institutions were evaluated. MOF incidence decreased over time (from 17% in 2003–2004 to 9.8% in 2009–2010). MOF-related death rate (33% in 2003–2004 to 36% in 2009–2010), intensive care unit stay, and mechanical ventilation duration did not change over the study period. Adjustment for admission risk factors confirmed the crude trends. MOF patients required much longer ventilation and intensive care unit stay, compared with non-MOF patients. Most of the MOF-related deaths occurred within 2 days of the MOF diagnosis. Lung and cardiac dysfunctions became less frequent (57.6% to 50.8%, 20.9% to 12.5%, respectively), but kidney and liver failure rates did not change (10.1% to 12.5%, 15.2% to 14.1%). CONCLUSION Postinjury MOF remains a resource-intensive, morbid, and lethal condition. Lung injury is an enduring challenge and should be a research priority. The lack of outcome improvements suggests that reversing MOF is difficult and prevention is still the best strategy. LEVEL OF EVIDENCE Epidemiologic study, level III. PMID:24553523

Community ecology in 3D: Tensor decomposition reveals spatio-temporal dynamics of large ecological communities.

PubMed

Frelat, Romain; Lindegren, Martin; Denker, Tim Spaanheden; Floeter, Jens; Fock, Heino O; Sguotti, Camilla; Stäbler, Moritz; Otto, Saskia A; Möllmann, Christian

2017-01-01

Understanding spatio-temporal dynamics of biotic communities containing large numbers of species is crucial to guide ecosystem management and conservation efforts. However, traditional approaches usually focus on studying community dynamics either in space or in time, often failing to fully account for interlinked spatio-temporal changes. In this study, we demonstrate and promote the use of tensor decomposition for disentangling spatio-temporal community dynamics in long-term monitoring data. Tensor decomposition builds on traditional multivariate statistics (e.g. Principal Component Analysis) but extends it to multiple dimensions. This extension allows for the synchronized study of multiple ecological variables measured repeatedly in time and space. We applied this comprehensive approach to explore the spatio-temporal dynamics of 65 demersal fish species in the North Sea, a marine ecosystem strongly altered by human activities and climate change. Our case study demonstrates how tensor decomposition can successfully (i) characterize the main spatio-temporal patterns and trends in species abundances, (ii) identify sub-communities of species that share similar spatial distribution and temporal dynamics, and (iii) reveal external drivers of change. Our results revealed a strong spatial structure in fish assemblages persistent over time and linked to differences in depth, primary production and seasonality. Furthermore, we simultaneously characterized important temporal distribution changes related to the low frequency temperature variability inherent in the Atlantic Multidecadal Oscillation. Finally, we identified six major sub-communities composed of species sharing similar spatial distribution patterns and temporal dynamics. Our case study demonstrates the application and benefits of using tensor decomposition for studying complex community data sets usually derived from large-scale monitoring programs.

Temporal trend and climate factors of hemorrhagic fever with renal syndrome epidemic in Shenyang City, China

PubMed Central

2011-01-01

Background Hemorrhagic fever with renal syndrome (HFRS) is an important infectious disease caused by different species of hantaviruses. As a rodent-borne disease with a seasonal distribution, external environmental factors including climate factors may play a significant role in its transmission. The city of Shenyang is one of the most seriously endemic areas for HFRS. Here, we characterized the dynamic temporal trend of HFRS, and identified climate-related risk factors and their roles in HFRS transmission in Shenyang, China. Methods The annual and monthly cumulative numbers of HFRS cases from 2004 to 2009 were calculated and plotted to show the annual and seasonal fluctuation in Shenyang. Cross-correlation and autocorrelation analyses were performed to detect the lagged effect of climate factors on HFRS transmission and the autocorrelation of monthly HFRS cases. Principal component analysis was constructed by using climate data from 2004 to 2009 to extract principal components of climate factors to reduce co-linearity. The extracted principal components and autocorrelation terms of monthly HFRS cases were added into a multiple regression model called principal components regression model (PCR) to quantify the relationship between climate factors, autocorrelation terms and transmission of HFRS. The PCR model was compared to a general multiple regression model conducted only with climate factors as independent variables. Results A distinctly declining temporal trend of annual HFRS incidence was identified. HFRS cases were reported every month, and the two peak periods occurred in spring (March to May) and winter (November to January), during which, nearly 75% of the HFRS cases were reported. Three principal components were extracted with a cumulative contribution rate of 86.06%. Component 1 represented MinRH0, MT1, RH1, and MWV1; component 2 represented RH2, MaxT3, and MAP3; and component 3 represented MaxT2, MAP2, and MWV2. The PCR model was composed of three principal components and two autocorrelation terms. The association between HFRS epidemics and climate factors was better explained in the PCR model (F = 446.452, P < 0.001, adjusted R2 = 0.75) than in the general multiple regression model (F = 223.670, P < 0.000, adjusted R2 = 0.51). Conclusion The temporal distribution of HFRS in Shenyang varied in different years with a distinctly declining trend. The monthly trends of HFRS were significantly associated with local temperature, relative humidity, precipitation, air pressure, and wind velocity of the different previous months. The model conducted in this study will make HFRS surveillance simpler and the control of HFRS more targeted in Shenyang. PMID:22133347

Exploratory Temporal and Spatial Analysis of Myocardial Infarction Hospitalizations in Calgary, Canada

PubMed Central

Liu, Xiaoxiao; Bertazzon, Stefania

2017-01-01

Spatial and temporal analyses are critical to understand the pattern of myocardial infarction (MI) hospitalizations over space and time, and to identify their underlying determinants. In this paper, we analyze MI hospitalizations in Calgary from 2004 to 2013, stratified by age and gender. First, a seasonal trend decomposition analyzes the seasonality; then a linear regression models the trend component. Moran’s I and hot spot analyses explore the spatial pattern. Though exploratory, results show that most age and gender groups feature a statistically significant decline over the 10 years, consistent with previous studies in Canada. Decline rates vary across ages and genders, with the slowest decline observed for younger males. Each gender exhibits a seasonal pattern with peaks in both winter and summer. Spatially, MI hot spots are identified in older communities, and in socioeconomically and environmentally disadvantaged communities. In the older communities, higher MI rates appear to be more highly associated with demographics. Conversely, worse air quality appears to be locally associated with higher MI incidence in younger age groups. The study helps identify areas of concern, where MI hot spots are identified for younger age groups, suggesting the need for localized public health policies to target local risk factors. PMID:29232910

Spatial and temporal patterns in concentrations of perfluorinated compounds in bald eagle nestlings in the Upper Midwestern United States

USGS Publications Warehouse

Route, William T.; Russell, Robin E.; Lindstrom, Andrew B.; Strynor, Mark J.; Key, Rebecca L.

2014-01-01

Perfluorinated chemicals (PFCs) are of concern due to their widespread use, persistence in the environment, tendency to accumulate in animal tissues, and growing evidence of toxicity. Between 2006 and 2011 we collected blood plasma from 261 bald eagle nestlings in six study areas from the upper Midwestern United States. Samples were assessed for levels of 16 different PFCs. We used regression analysis in a Bayesian framework to evaluate spatial and temporal trends for these analytes. We found levels as high as 7370 ng/mL for the sum of all 16 PFCs (∑PFCs). Perfluorooctanesulfonate (PFOS) and perfluorodecanesulfonate (PFDS) were the most abundant analytes, making up 67% and 23% of the PFC burden, respectively. Levels of ∑PFC, PFOS, and PFDS were highest in more urban and industrial areas, moderate on Lake Superior, and low on the remote upper St. Croix River watershed. We found evidence of declines in ∑PFCs and seven analytes, including PFOS, PFDS, and perfluorooctanoic acid (PFOA); no trend in two analytes; and increases in two analytes. We argue that PFDS, a long-chained PFC with potential for high bioaccumulation and toxicity, should be considered for future animal and human studies.

Propelled microprobes in turbulence

NASA Astrophysics Data System (ADS)

Calzavarini, E.; Huang, Y. X.; Schmitt, F. G.; Wang, L. P.

2018-05-01

The temporal statistics of incompressible fluid velocity and passive scalar fields in developed turbulent conditions is investigated by means of direct numerical simulations along the trajectories of self-propelled pointlike probes drifting in a flow. Such probes are characterized by a propulsion velocity which is fixed in intensity and direction; however, like vessels in a flow they are continuously deviated on their intended course as the result of local sweeping of the fluid flow. The recorded time series by these moving probes represent the simplest realization of transect measurements in a fluid flow environment. We investigate the nontrivial combination of Lagrangian and Eulerian statistical properties displayed by the transect time series. We show that, as a result of the homogeneity and isotropy of the flow, the single-point acceleration statistics of the probes follows a predictable trend at varying the propulsion speed, a feature that is also present in the scalar time-derivative fluctuations. Further, by focusing on two-time statistics we characterize how the Lagrangian-to-Eulerian transition occurs at increasing the propulsion velocity. The analysis of intermittency of temporal increments highlights in a striking way the opposite trends displayed by the fluid velocity and passive scalars.

Spatiotemporal hurdle models for zero-inflated count data: Exploring trends in emergency department visits.

PubMed

Neelon, Brian; Chang, Howard H; Ling, Qiang; Hastings, Nicole S

2016-12-01

Motivated by a study exploring spatiotemporal trends in emergency department use, we develop a class of two-part hurdle models for the analysis of zero-inflated areal count data. The models consist of two components-one for the probability of any emergency department use and one for the number of emergency department visits given use. Through a hierarchical structure, the models incorporate both patient- and region-level predictors, as well as spatially and temporally correlated random effects for each model component. The random effects are assigned multivariate conditionally autoregressive priors, which induce dependence between the components and provide spatial and temporal smoothing across adjacent spatial units and time periods, resulting in improved inferences. To accommodate potential overdispersion, we consider a range of parametric specifications for the positive counts, including truncated negative binomial and generalized Poisson distributions. We adopt a Bayesian inferential approach, and posterior computation is handled conveniently within standard Bayesian software. Our results indicate that the negative binomial and generalized Poisson hurdle models vastly outperform the Poisson hurdle model, demonstrating that overdispersed hurdle models provide a useful approach to analyzing zero-inflated spatiotemporal data. © The Author(s) 2014.

Investigating the association between weather conditions, calendar events and socio-economic patterns with trends in fire incidence: an Australian case study

NASA Astrophysics Data System (ADS)

Corcoran, Jonathan; Higgs, Gary; Rohde, David; Chhetri, Prem

2011-06-01

Fires in urban areas can cause significant economic, physical and psychological damage. Despite this, there has been a comparative lack of research into the spatial and temporal analysis of fire incidence in urban contexts. In this paper, we redress this gap through an exploration of the association of fire incidence to weather, calendar events and socio-economic characteristics in South-East Queensland, Australia using innovative technique termed the quad plot. Analysing trends in five fire incident types, including malicious false alarms (hoax calls), residential buildings, secondary (outdoor), vehicle and suspicious fires, results suggest that risk associated with all is greatly increased during school holidays and during long weekends. For all fire types the lowest risk of incidence was found to occur between one and six a.m. It was also found that there was a higher fire incidence in socially disadvantaged neighbourhoods and there was some evidence to suggest that there may be a compounding impact of high temperatures in such areas. We suggest that these findings may be used to guide the operations of fire services through spatial and temporal targeting to better utilise finite resources, help mitigate risk and reduce casualties.

Spatial-temporal trend and health implications of polycyclic aromatic hydrocarbons (PAHs) in resident oysters, South China Sea: A case study of Eastern Guangdong coast.

PubMed

Yu, Zi-Ling; Lin, Qin; Gu, Yang-Guang; Ke, Chang-Liang; Sun, Run-Xia

2016-09-15

Spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) were investigated in Eastern Guangdong coast, China. Total PAH concentrations in oysters ranged from 231 to 1178ng/g with a mean concentration of 622ng/g dry weight. Compared with other bays and estuaries, PAH levels in oysters were moderate. Spatial distribution of PAHs was site specific, with relatively high PAH concentrations observed in Zhelin Bay and Kaozhouyang Bay. Based on the Spearman test analysis, only PAH concentration in oysters from Jiazi Harbor showed a significant increasing trend (P<0.05). Three-ring PAHs were the most abundant, accounting for 54.2%-88.4% of total PAHs. Diagnostic ratios suggested that PAHs were derived mainly from petroleum origin. BaP and ∑4PAH concentrations were well within the European Union limits (5ng/g and 30ng/g wet weight, respectively). The incremental lifetime cancer risks (ILCR) for PAHs were <10(-5), indicating that the adverse health risks associated with oyster consumption in this area were minimal. Copyright © 2016 Elsevier Ltd. All rights reserved.

EYE MOVEMENT RECORDING AND NONLINEAR DYNAMICS ANALYSIS – THE CASE OF SACCADES#

PubMed Central

Aştefănoaei, Corina; Pretegiani, Elena; Optican, L.M.; Creangă, Dorina; Rufa, Alessandra

2015-01-01

Evidence of a chaotic behavioral trend in eye movement dynamics was examined in the case of a saccadic temporal series collected from a healthy human subject. Saccades are highvelocity eye movements of very short duration, their recording being relatively accessible, so that the resulting data series could be studied computationally for understanding the neural processing in a motor system. The aim of this study was to assess the complexity degree in the eye movement dynamics. To do this we analyzed the saccadic temporal series recorded with an infrared camera eye tracker from a healthy human subject in a special experimental arrangement which provides continuous records of eye position, both saccades (eye shifting movements) and fixations (focusing over regions of interest, with rapid, small fluctuations). The semi-quantitative approach used in this paper in studying the eye functioning from the viewpoint of non-linear dynamics was accomplished by some computational tests (power spectrum, portrait in the state space and its fractal dimension, Hurst exponent and largest Lyapunov exponent) derived from chaos theory. A high complexity dynamical trend was found. Lyapunov largest exponent test suggested bi-stability of cellular membrane resting potential during saccadic experiment. PMID:25698889

Increased trend in extracorporeal membrane oxygenation use by adults in the United States since 2007.

PubMed

Gerke, Alicia K; Tang, Fan; Cavanaugh, Joseph E; Doerschug, Kevin C; Polgreen, Philip M

2015-11-18

Extracorporeal membrane oxygenation (ECMO) has been increasingly studied as a life support modality, but it is unclear if its use has changed over time. Recent publication shows no significant trend in use of ECMO over time; however, this report does not include more recent data. We performed trend analysis to determine if and when the use of ECMO changed in the past decade. We identified hospitalizations (2000-2011) in the Nationwide Inpatient Sample during which ECMO was recorded. We used a segmented linear regression model to determine trend and to identify a temporal change point when rate of ECMO use increased. ECMO use gradually grew until 2007, at which time there was a dramatic increase in the rate (p = 0.0003). There was no difference in mortality after 2007 (p = 0.3374), but there was longer length of stay (p = 0.0001) and smaller percentage of women (p = 0.005). There has been a marked increase in ECMO use since 2007. As ECMO use becomes more common, further study regarding indications, cost-effectiveness, and outcomes is warranted to guide optimal use.

Temporal changes and variability in temperature series over Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Suhaila, Jamaludin

2015-02-01

With the current concern over climate change, the descriptions on how temperature series changed over time are very useful. Annual mean temperature has been analyzed for several stations over Peninsular Malaysia. Non-parametric statistical techniques such as Mann-Kendall test and Theil-Sen slope estimation are used primarily for assessing the significance and detection of trends, while a nonparametric Pettitt's test and sequential Mann-Kendall test are adopted to detect any abrupt climate change. Statistically significance increasing trends for annual mean temperature are detected for almost all studied stations with the magnitude of significant trend varied from 0.02°C to 0.05°C per year. The results shows that climate over Peninsular Malaysia is getting warmer than before. In addition, the results of the abrupt changes in temperature using Pettitt's and sequential Mann-Kendall test reveal the beginning of trends which can be related to El Nino episodes that occur in Malaysia. In general, the analysis results can help local stakeholders and water managers to understand the risks and vulnerabilities related to climate change in terms of mean events in the region.

Relationship of number of seizures recorded on video-EEG to surgical outcome in refractory medial temporal lobe epilepsy

PubMed Central

Sainju, Rup Kamal; Wolf, Bethany Jacobs; Bonilha, Leonardo; Martz, Gabriel

2014-01-01

Introduction Surgical planning for refractory medial temporal lobe epilepsy (rMTLE) relies on seizure localization by ictal electroencephalography (EEG). Multiple factors impact the number of seizures recorded. We evaluated whether seizure freedom correlated to the number of seizures recorded, and the related factors. Methods We collected data for 32 patients with rMTLE who underwent anterior temporal lobectomy. Primary analysis evaluated number of seizures captured as a predictor of surgical outcome. Subsequent analyses explored factors that may seizure number. Results Number of seizures recorded did not predict seizure freedom. More seizures were recorded with more days of seizure occurrence (p<0.001), seizure clusters (p≤0.011) and poorly localized seizures (PLSz) (p=0.004). Regression modeling showed a trend for subjects with fewer recorded poorly localized seizures to have better surgical outcome (p=0.052). Conclusions Total number of recorded seizures does not predict surgical outcome. Patients with more PLSz may have worse outcome. PMID:22990726

Application of glas laser altimetry to detect elevation changes in East Antarctica

NASA Astrophysics Data System (ADS)

Scaioni, M.; Tong, X.; Li, R.

2013-10-01

In this paper the use of ICESat/GLAS laser altimeter for estimating multi-temporal elevation changes on polar ice sheets is afforded. Due to non-overlapping laser spots during repeat passes, interpolation methods are required to make comparisons. After reviewing the main methods described in the literature (crossover point analysis, cross-track DEM projection, space-temporal regressions), the last one has been chosen for its capability of providing more elevation change rate measurements. The standard implementation of the space-temporal linear regression technique has been revisited and improved to better cope with outliers and to check the estimability of model's parameters. GLAS data over the PANDA route in East Antarctica have been used for testing. Obtained results have been quite meaningful from a physical point of view, confirming the trend reported by the literature of a constant snow accumulation in the area during the two past decades, unlike the most part of the continent that has been losing mass.

ERP measures of partial semantic knowledge: left temporal indices of skill differences and lexical quality.

PubMed

Frishkoff, Gwen A; Perfetti, Charles A; Westbury, Chris

2009-01-01

This study examines the sensitivity of early event-related potentials (ERPs) to degrees of word semantic knowledge. Participants with strong, average, or weak vocabulary skills made speeded lexical decisions to letter strings. To represent the full spectrum of word knowledge among adult native-English speakers, we used rare words that were orthographically matched with more familiar words and with pseudowords. Since the lexical decision could not reliably be made on the basis of word form, subjects were obliged to use semantic knowledge to perform the task. A d' analysis suggested that high-skilled subjects adopted a more conservative strategy in response to rare versus more familiar words. Moreover, the high-skilled participants showed a trend towards an enhanced "N2c" to rare words, and a similar posterior temporal effect reached significance approximately 650 ms. Generators for these effects were localized to left temporal cortex. We discuss implications of these results for word learning and for theories of lexical semantic access.

Rising air and stream-water temperatures in Chesapeake Bay region, USA

USGS Publications Warehouse

Rice, Karen C.; Jastram, John D.

2015-01-01

Monthly mean air temperature (AT) at 85 sites and instantaneous stream-water temperature (WT) at 129 sites for 1960–2010 are examined for the mid-Atlantic region, USA. Temperature anomalies for two periods, 1961–1985 and 1985–2010, relative to the climate normal period of 1971–2000, indicate that the latter period was statistically significantly warmer than the former for both mean AT and WT. Statistically significant temporal trends across the region of 0.023 °C per year for AT and 0.028 °C per year for WT are detected using simple linear regression. Sensitivity analyses show that the irregularly sampled WT data are appropriate for trend analyses, resulting in conservative estimates of trend magnitude. Relations between 190 landscape factors and significant trends in AT-WT relations are examined using principal components analysis. Measures of major dams and deciduous forest are correlated with WT increasing slower than AT, whereas agriculture in the absence of major dams is correlated with WT increasing faster than AT. Increasing WT trends are detected despite increasing trends in streamflow in the northern part of the study area. Continued warming of contributing streams to Chesapeake Bay likely will result in shifts in distributions of aquatic biota and contribute to worsened eutrophic conditions in the bay and its estuaries.

Trends in the leading causes of death in Korea, 1983-2012.

PubMed

Lim, Daroh; Ha, Mina; Song, Inmyung

2014-12-01

This study aimed to analyze trends in the 10 leading causes of death in Korea from 1983 to 2012. Death rates were derived from the Korean Statistics Information Service database and age-adjusted to the 2010 population. Joinpoint regression analysis was used to identify the points when statistically significant changes occurred in the trends. Between 1983 and 2012, the age-standardized death rate (ASR) from all causes decreased by 61.6% for men and 51.2% for women. ASRs from malignant neoplasms, diabetes mellitus, and transport accidents increased initially before decreasing. ASRs from hypertensive diseases, heart diseases, cerebrovascular diseases and diseases of the liver showed favorable trends (ASR % change: -94.4%, -53.8%, -76.0%, and -78.9% for men, and -77.1%, -36.5%, -67.8%, and -79.9% for women, respectively). ASRs from pneumonia decreased until the mid-1990s and thereafter increased. ASRs from intentional self-harm increased persistently since around 1990 (ASR % change: 122.0% for men and 217.4% for women). In conclusion, death rates from all causes in Korea decreased significantly in the last three decades except in the late 1990s. Despite the great strides made in the overall mortality, temporal trends varied widely by cause. Mortality trends for malignant neoplasms, diabetes mellitus, pneumonia and intentional self-harm were unfavorable.

Identifying water-quality trends in the Trinity River, Texas, USA, 1969-1992, using sediment cores from Lake Livingston

USGS Publications Warehouse

Van Metre, P.C.; Callender, E.

1996-01-01

Chemical analyses were done on cores of bottom sediment from three locations in Lake Livingston, a reservoir on the Trinity River in east Texas to identify trends in water quality in the Trinity River using the chemical record preserved in bottom sediments trapped by the reservoir. Sediment cores spanned the period from 1969, when the reservoir was impounded, to 1992, when the cores were collected. Chemical concentrations in reservoir sediment samples were compared to concentrations for 14 streambed sediment samples from the Trinity River Basin and to reported concentrations for soils in the eastern United States and shale. These comparisons indicate that sediments deposited in Lake Livingston are representative of the environmental setting of Lake Livingston within the Trinity River Basin. Vertical changes in concentrations within sediment cores indicate temporal trends of decreasing concentrations of lead, sodium, barium, and total DDT (DDT plus its metabolites DDD and DDE) in the Trinity River. Possible increasing temporal trends are indicated for chlordane and dieldrin. Each sediment-derived trend is related to trends in water quality in the Trinity River or known changes in environmental factors in its drainage basin or both.

Global trends in satellite-based emergency mapping.

PubMed

Voigt, Stefan; Giulio-Tonolo, Fabio; Lyons, Josh; Kučera, Jan; Jones, Brenda; Schneiderhan, Tobias; Platzeck, Gabriel; Kaku, Kazuya; Hazarika, Manzul Kumar; Czaran, Lorant; Li, Suju; Pedersen, Wendi; James, Godstime Kadiri; Proy, Catherine; Muthike, Denis Macharia; Bequignon, Jerome; Guha-Sapir, Debarati

2016-07-15

Over the past 15 years, scientists and disaster responders have increasingly used satellite-based Earth observations for global rapid assessment of disaster situations. We review global trends in satellite rapid response and emergency mapping from 2000 to 2014, analyzing more than 1000 incidents in which satellite monitoring was used for assessing major disaster situations. We provide a synthesis of spatial patterns and temporal trends in global satellite emergency mapping efforts and show that satellite-based emergency mapping is most intensively deployed in Asia and Europe and follows well the geographic, physical, and temporal distributions of global natural disasters. We present an outlook on the future use of Earth observation technology for disaster response and mitigation by putting past and current developments into context and perspective. Copyright © 2016, American Association for the Advancement of Science.

Different trends in extreme and median surface aerosol extinction coefficients over China inferred from quality-controlled visibility data

NASA Astrophysics Data System (ADS)

Li, Jing; Li, Chengcai; Zhao, Chunsheng

2018-03-01

Although the temporal changes in aerosol properties have been widely investigated, the majority of studies has focused on average conditions without much emphasis on the extremes. However, the latter can be more important in terms of human health and climate change. This study uses a previously validated, quality-controlled visibility dataset to investigate the long-term trends (expressed in terms of relative changes) in extreme surface aerosol extinction coefficient (AEC) over China and compares them with the median trends. Two methods are used to independently evaluate the trends, which arrive at consistent results. The signs of extreme and median trends are generally coherent, whereas their magnitudes show distinct spatial and temporal differences. In the 1980s, an overall positive trend is found throughout China with the extreme trend exceeding the mean trend, except for northwest China and the North China Plain. In the 1990s, AEC over northeast and northwest China started to decline while the rest of the country still exhibited an increase. The extreme trends continued to dominate in the south while they yielded to the mean trend in the north. After the year 2000, the extreme trend became weaker than the mean trend overall in terms of both the magnitude and significance level. The annual trend can be primarily attributed to winter and fall trends. The results suggest that the decadal changes in pollution in China may be governed by different mechanisms. Synoptic conditions that often result in extreme air quality changes might have dominated in the 1980s, whereas emission increase might have been the main factor for the 2000s.

Trends in upper gastrointestinal diagnosis over four decades in Lusaka, Zambia: a retrospective analysis of endoscopic findings.

PubMed

Kayamba, Violet; Sinkala, Edford; Mwanamakondo, Stayner; Soko, Rose; Kawimbe, Boniface; Amadi, Beatrice; Zulu, Isaac; Nzaisenga, Jean-Baptiste; Banda, Themba; Mumbwe, Chipasha; Phiri, Evans; Munkonge, Philip; Kelly, Paul

2015-10-06

There a shortage of robust information about profiles of gastrointestinal disease in sub-Saharan Africa. The endoscopy unit of the University Teaching Hospital in Lusaka has been running without interruption since 1977 and this 38-year record is largely intact. We report an analysis of endoscopic findings over this period. Written endoscopy records from 29th September 1977 to 16th December 2014 were recovered, computerised, coded by two experienced endoscopists and analysed. Temporal trends were analysed using tables, graphs, and unconditional logistic regression, with age, sex of patient, decade, and endoscopist as independent variables to adjust for inter-observer variation. Sixteen thousand nine hundred fifty-three records were identified and analysed. Diagnosis of gastric ulcer rose by 22 %, and that of duodenal ulcer fell by 14 % per decade. Endoscopically diagnosed oesophageal cancer increased by 32 % per decade, but gastric cancer rose only in patients under 60 years of age (21 % per decade). Oesophageal varices were the commonest finding in patients presenting with haematemesis, increasing by 14 % per decade in that patient group. Two HIV-related diagnoses, oesophageal candidiasis and Kaposi's sarcoma, rose from almost zero to very high levels in the 1990s but fell substantially after 2005 when anti-retroviral therapy became widely available. This useful dataset suggests that there are important trends in some endoscopic findings over four decades. These trends are not explained by inter-observer variation. Reasons for the divergent trends in incidence of peptic ulceration and apparent trends in diagnosis of upper gastrointestinal cancers merit further exploration.

Sirenomelia in Argentina: Prevalence, geographic clusters and temporal trends analysis.

PubMed

Groisman, Boris; Liascovich, Rosa; Gili, Juan Antonio; Barbero, Pablo; Bidondo, María Paz

2016-07-01

Sirenomelia is a severe malformation of the lower body characterized by a single medial lower limb and a variable combination of visceral abnormalities. Given that Sirenomelia is a very rare birth defect, epidemiological studies are scarce. The aim of this study is to evaluate prevalence, geographic clusters and time trends of sirenomelia in Argentina, using data from the National Network of Congenital Anomalies of Argentina (RENAC) from November 2009 until December 2014. This is a descriptive study using data from the RENAC, a hospital-based surveillance system for newborns affected with major morphological congenital anomalies. We calculated sirenomelia prevalence throughout the period, searched for geographical clusters, and evaluated time trends. The prevalence of confirmed cases of sirenomelia throughout the period was 2.35 per 100,000 births. Cluster analysis showed no statistically significant geographical aggregates. Time-trends analysis showed that the prevalence was higher in years 2009 to 2010. The observed prevalence was higher than the observed in previous epidemiological studies in other geographic regions. We observed a likely real increase in the initial period of our study. We used strict diagnostic criteria, excluding cases that only had clinical diagnosis of sirenomelia. Therefore, real prevalence could be even higher. This study did not show any geographic clusters. Because etiology of sirenomelia has not yet been established, studies of epidemiological features of this defect may contribute to define its causes. Birth Defects Research (Part A) 106:604-611, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Recurrent jellyfish blooms are a consequence of global oscillations

PubMed Central

Condon, Robert H.; Duarte, Carlos M.; Pitt, Kylie A.; Robinson, Kelly L.; Lucas, Cathy H.; Sutherland, Kelly R.; Mianzan, Hermes W.; Bogeberg, Molly; Purcell, Jennifer E.; Decker, Mary Beth; Uye, Shin-ichi; Madin, Laurence P.; Brodeur, Richard D.; Haddock, Steven H. D.; Malej, Alenka; Parry, Gregory D.; Eriksen, Elena; Quiñones, Javier; Acha, Marcelo; Harvey, Michel; Arthur, James M.; Graham, William M.

2013-01-01

A perceived recent increase in global jellyfish abundance has been portrayed as a symptom of degraded oceans. This perception is based primarily on a few case studies and anecdotal evidence, but a formal analysis of global temporal trends in jellyfish populations has been missing. Here, we analyze all available long-term datasets on changes in jellyfish abundance across multiple coastal stations, using linear and logistic mixed models and effect-size analysis to show that there is no robust evidence for a global increase in jellyfish. Although there has been a small linear increase in jellyfish since the 1970s, this trend was unsubstantiated by effect-size analysis that showed no difference in the proportion of increasing vs. decreasing jellyfish populations over all time periods examined. Rather, the strongest nonrandom trend indicated jellyfish populations undergo larger, worldwide oscillations with an approximate 20-y periodicity, including a rising phase during the 1990s that contributed to the perception of a global increase in jellyfish abundance. Sustained monitoring is required over the next decade to elucidate with statistical confidence whether the weak increasing linear trend in jellyfish after 1970 is an actual shift in the baseline or part of an oscillation. Irrespective of the nature of increase, given the potential damage posed by jellyfish blooms to fisheries, tourism, and other human industries, our findings foretell recurrent phases of rise and fall in jellyfish populations that society should be prepared to face. PMID:23277544

An Ongoing Shift in Pacific Ocean Sea Level

NASA Astrophysics Data System (ADS)

Cheon, S. H.; Hamlington, B.; Thompson, P. R.; Merrifield, M. A.; Nerem, R. S.; Leben, R. R.; Kim, K. Y.

2016-12-01

According to the satellite altimeter data, local sea level trends have shown considerable diversity spatially as well as temporally. In particular, dramatic changes in sea level in the Pacific have been observed throughout the altimeter record, with high trends in the western tropical Pacific (WTP) and comparatively lower trends in the eastern Pacific. In recent years, however, a shift appears to be occurring, with falling trends in the (WTP) and rising trends in the eastern tropical and northeastern Pacific (ETP and NEP). From a planning perspective, it is important to figure out whether these sharp changes are part of a short-term shift or the beginning of a longer-term change in sea level. In this study, we distinguish the origins of the recent shift in Pacific Ocean sea level. Cyclostationary empirical orthogonal function (CSEOF) analysis is applied to separate the properties of the recent sea level change in the Pacific Ocean. From the CSEOF analysis results, we point out two dominant modes of sea level shift in the Pacific Ocean. The first mode is related to the biennial oscillation associated with El Nino-Southern Oscillation (ENSO) and the other is related to lower-frequency variability with a strong signal in the northern Pacific. Considering a relatively high correlation between recent sea level change and the low-frequency mode, we suggest that the low-frequency mode has played a dominant role in the sea level shift in the Pacific Ocean. Using a reconstructed sea level dataset, we examine the variability of this low-frequency mode in the past, and find similar periods of dramatic sea level change in the Pacific. Based on the sea level record of the last five years and according to the analysis, we conclude that in the coming decades, higher sea level trends off the U.S. West Coast should be expected, while reduced trends in the WTP will likely be observed.

Regional Landslide Mapping Aided by Automated Classification of SqueeSAR™ Time Series (Northern Apennines, Italy)

NASA Astrophysics Data System (ADS)

Iannacone, J.; Berti, M.; Allievi, J.; Del Conte, S.; Corsini, A.

2013-12-01

Space borne InSAR has proven to be very valuable for landslides detection. In particular, extremely slow landslides (Cruden and Varnes, 1996) can be now clearly identified, thanks to the millimetric precision reached by recent multi-interferometric algorithms. The typical approach in radar interpretation for landslides mapping is based on average annual velocity of the deformation which is calculated over the entire times series. The Hotspot and Cluster Analysis (Lu et al., 2012) and the PSI-based matrix approach (Cigna et al., 2013) are examples of landslides mapping techniques based on average annual velocities. However, slope movements can be affected by non-linear deformation trends, (i.e. reactivation of dormant landslides, deceleration due to natural or man-made slope stabilization, seasonal activity, etc). Therefore, analyzing deformation time series is crucial in order to fully characterize slope dynamics. While this is relatively simple to be carried out manually when dealing with small dataset, the time series analysis over regional scale dataset requires automated classification procedures. Berti et al. (2013) developed an automatic procedure for the analysis of InSAR time series based on a sequence of statistical tests. The analysis allows to classify the time series into six distinctive target trends (0=uncorrelated; 1=linear; 2=quadratic; 3=bilinear; 4=discontinuous without constant velocity; 5=discontinuous with change in velocity) which are likely to represent different slope processes. The analysis also provides a series of descriptive parameters which can be used to characterize the temporal changes of ground motion. All the classification algorithms were integrated into a Graphical User Interface called PSTime. We investigated an area of about 2000 km2 in the Northern Apennines of Italy by using SqueeSAR™ algorithm (Ferretti et al., 2011). Two Radarsat-1 data stack, comprising of 112 scenes in descending orbit and 124 scenes in ascending orbit, were processed. The time coverage lasts from April 2003 to November 2012, with an average temporal frequency of 1 scene/month. Radar interpretation has been carried out by considering average annual velocities as well as acceleration/deceleration trends evidenced by PSTime. Altogether, from ascending and descending geometries respectively, this approach allowed detecting of 115 and 112 potential landslides on the basis of average displacement rate and 77 and 79 landslides on the basis of acceleration trends. In conclusion, time series analysis resulted to be very valuable for landslide mapping. In particular it highlighted areas with marked acceleration in a specific period in time while still being affected by low average annual velocity over the entire analysis period. On the other hand, even in areas with high average annual velocity, time series analysis was of primary importance to characterize the slope dynamics in terms of acceleration events.

Bariatric surgery interest around the world: what Google Trends can teach us.

PubMed

Linkov, Faina; Bovbjerg, Dana H; Freese, Kyle E; Ramanathan, Ramesh; Eid, George Michel; Gourash, William

2014-01-01

Bariatric surgery may prove an effective weight loss option for those struggling with severe obesity, but it is difficult to determine levels of interest in such procedures at the population level through traditional approaches. Analysis of Google Trend information may give providers and healthcare systems useful information regarding Internet users' interest in bariatric procedures. The objective of this study was to gather Google Trend information on worldwide Internet searches for "bariatric surgery", "gastric bypass", "gastric sleeve", "gastric plication", and "lap band" from 2004-2012 and to explore temporal relationships with relevant media events, economic variations, and policy modifications. Data were collected using Google Trends. Trend analyses were performed using Microsoft Excel Version 14.3.5 and Minitab V.16.0. Trend analyses showed that total search volume for the term "bariatric surgery" has declined roughly 25% since January 2004, although interest increased approximately 5% from 2011 to 2012. Interest in lap band procedures declined 30% over the past 5 years, while "gastric sleeve" has increased 15%. Spikes in search numbers show an association with events such as changing policy and insurance guidelines and media coverage for bariatric procedures. This report illustrates that variations in Internet search volume for terms related to bariatric surgery are multifactorial in origin. Although it is impossible to ascertain if reported Internet search volume is based on interest in potentially undergoing bariatric surgery or simply general interest, this analysis reveals that search volume appears to mirror real world events. Therefore, Google Trends could be a way to supplement understanding about interest in bariatric procedures. © 2013 American Society for Bariatric Surgery Published by American Society for Metabolic and Bariatric Surgery All rights reserved.

Long-Term Vegetation Trends Detected In Northern Canada Using Landsat Image Stacks

NASA Astrophysics Data System (ADS)

Fraser, R.; Olthof, I.; Carrière, M.; Deschamps, A.; Pouliot, D.

2011-12-01

Evidence of recent productivity increases in arctic vegetation comes from a variety of sources. At local scales, long-term plot measurements in North America are beginning to record increases in vascular plant cover and biomass. At landscape scales, expansion and densification of shrubs has been observed using repeat oblique photographs. Finally, continental-scale increases in vegetation "greenness" have been documented based on analysis of coarse resolution (≥ 1 km) NOAA-AVHRR satellite imagery. In this study we investigated intermediate, regional-level changes occurring in tundra vegetation since 1984 using the Landsat TM and ETM+ satellite image archive. Four study areas averaging 13,619 km2 were located over widely distributed national parks in northern Canada (Ivvavik, Sirmilik, Torngat Mountains, and Wapusk). Time-series image stacks of 16-41 growing-season Landsat scenes from overlapping WRS-2 frames were acquired spanning periods of 17-25 years. Each pixel's unique temporal database of clear-sky values was then analyzed for trends in four indices (NDVI, Tasseled Cap Brightness, Greenness and Wetness) using robust linear regression. The trends were further related to changes in the fractional cover of functional vegetation types using regression tree models trained with plot data and high resolution (≤ 10 m) satellite imagery. We found all four study areas to have a larger proportion of significant (p<0.05) positive greenness trends (range 6.1-25.5%) by comparison to negative trends (range 0.3-4.1%). For the three study areas where regression tree models could be derived, consistent trends of increasing shrub or vascular fractional cover and decreasing bare cover were predicted. The Landsat-based observations were associated with warming trends in each park over the analysis periods. Many of the major changes observed could be corroborated using published studies or field observations.

Evolving trends in sinus surgery: What is the impact of balloon sinus dilation?

PubMed

Svider, Peter F; Darlin, Spencer; Bobian, Michael; Sekhsaria, Vibhav; Harvey, Richard J; Gray, Stacey T; Baredes, Soly; Folbe, Adam J; Eloy, Jean Anderson

2018-06-01

Balloon dilation (BD) represents a minimally invasive alternative to endoscopic sinus surgery (ESS). Although BD was introduced in 2006, distinct Current Procedural Terminology (CPT) codes were not available until 2011, making prior analysis of population-based trends difficult. Our objectives were to evaluate these trends and compare any changes to the use of traditional ESS techniques. Geographic trends also were evaluated. Medicare Part B national datasets encompassing procedures from 2011 to 2015 were obtained. ESS CPT codes (frontal sinusotomy, maxillary antrostomy with/without tissue removal, sphenoidotomy) and BD codes were searched to determine temporal trends in their use. Additionally, state carriers were individually evaluated for geographic trends. National use of BD increased greater than five-fold (39,193 from 7,496 among Medicare patients), whereas the use of ESS increased by only 5.9%. This increase in BD was observed across all sites, including the sphenoid (7.0x), maxillary (5.1x), and frontal (4.7x) sinuses. In the most recent year for which data was available (2015), a significantly greater portion of sinus procedures in these sites utilized BD in the South (42.1%) compared to the Northeast (30.6%), West (29.5%), and Midwest (25.3%) regions (P < 0.0001). The performance of BD has increased markedly in recent years. Because the use of ESS codes remain stable, observed BD trends are unlikely to be due simply to greater familiarity with newer CPT coding. The reasons for the striking increase in BD popularity are speculative and beyond the scope of this analysis, but further study may be needed. NA. Laryngoscope, 128:1299-1303, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

[Self-rated health and educational level in Spain: trends by autonomous communities and gender (2001-2012)].

PubMed

Aguilar-Palacio, Isabel; Carrera-Lasfuentes, Patricia; Rabanaque, M José

2015-01-01

To identify the trend in self-rated health in Spain by autonomous communities (AC) in the period 2001-2012, as well as differences by gender and age, and the influence of educational level. A cross sectional study was carried out using data from the National Health Surveys from 2001 to 2011-12 and the 2009 European Survey. A descriptive analysis was conducted that included gender, age, educational level, and the AC of residence. Logistic regression analyses were developed to explore the temporal trend and the association between educational level and self-rated health. The predictive capacity of the model was calculated using the C statistic. The prevalence of low self-rated health was higher in women with low educational level. Self-rated health improved in women with high educational level (2001:18.6% vs. 2012:14.6%). The highest prevalence of low self-rated health was observed in Andalusia, the Canary Islands, Galicia and Murcia, with differences by gender. Low educational level was associated with low self-rated health in most AC, with good predictive capacity. In all AC except Asturias, low self-rated health was more frequent in women than in men. In Spain, the prevalence of self-rated health showed no variations in the period analyzed and improved in the Balearic Islands, Catalonia, and Madrid. The prevalence of self-rated health in Spain differed by AC. Although health was unchanged during the period considered, inequalities were found in its temporal trend by educational level and gender, which could lead to an increase in health inequalities in women according educational level. Copyright © 2014 SESPAS. Published by Elsevier Espana. All rights reserved.

Longitudinal measures of perfluoroalkyl substances (PFAS) in serum of Gullah African Americans in South Carolina: 2003–2013

PubMed Central

Gribble, Matthew O.; Bartell, Scott M.; Kannan, Kurunthachalam; Wu, Qian; Fair, Patricia A.; Kamen, Diane L.

2015-01-01

Background Charleston Harbor has elevated concentrations of PFAS in dolphins, but local human exposure data are limited. Objectives We sought to describe PFAS serum concentrations’ temporal trends among Gullah African American residents of coastal South Carolina. Methods Longitudinal measures of PFAS in blood serum from a Gullah clinical sample, without lupus, were examined using spaghetti plots and visit-to-visit change scores (e.g., differences in concentrations between visits) among the 68 participants with repeated measures available. We also modeled population-level trends among the 71 participants with any data using proportionate percentile models, accounting for clustering through robust standard errors. In a post-hoc analysis we examined heterogeneity of temporal trends by age through mixed-effects models for the log-transformed PFAS compounds. Results Population concentrations of PFOS dropped approximately 9 (95% CI: 8, 10) percent each year over 2003–2013. This was concordant with individual PFOS trajectories (median PFOS change score −21.7 ng/g wet weight, interquartile range of PFOS change scores: −32.8, −14.9) and reports for other populations over this time period. Several other compounds including PFOA, PFHxS, and PFuNDA also showed a population-level decrease. However, examination of individual trajectories suggested substantial heterogeneity. Post-hoc analyses indicated that PFAS trajectories were heterogeneous by age. Conclusions Many PFAS compounds are decreasing in a sample of Gullah African Americans from coastal South Carolina. There may be age differences in the elimination kinetics of PFASs. The possible role of age as a modifier of PFAS serum trends merits further research. PMID:25819541

The epidemiology of Scottish trauma: A comparison of pre-hospital and in-hospital deaths, 2000 to 2011.

PubMed

Morrison, Jonathan J; Yapp, Liam Z; Beattie, Anne; Devlin, Eimar; Samarage, Milan; McCaffer, Craig; Jansen, Jan O

2016-02-01

To characterise the temporal trends and urban-rural distribution of fatal injuries in Scotland through the analysis of mortality data collected by the National Records of Scotland. The prospectively collected NRS database was queried using ICD-10 codes for all Scottish trauma deaths during the period 2000 to 2011. Patients were divided into pre-hospital and in-hospital groups depending on the location of death. Incidence was plotted against time and linear regression was used to identify temporal trends. A total of 13,100 deaths were analysed. There were 4755 (36.3%) patients in the pre-hospital group with a median age (IQR) of 42 (28-58) years. The predominant cause of pre-hospital death related to vehicular injury (27.8%), which had a decreasing trend over the study period (p = 0.004). In-hospital, patients had a median age of 80 (58-88) years and the majority (67.0%) of deaths occurred following a fall on the level. This trend was shown to increase over the decade of study (p = 0.020). In addition, the incidence of urban incidents remained static, but the rate of rural fatal trauma decreased (p < 0.001). Around a third of Scottish trauma patients die prior to hospital admission and the predominant mechanism of injury is due to road traffic accidents. This contrasts with in-hospital deaths, which are mainly observed in elderly patients following a fall from standing height. Further research is required to determine the preventability of fatal traumatic injury in Scotland. Copyright © 2015 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.

On the temporal and spatial characteristics of tornado days in the United States

NASA Astrophysics Data System (ADS)

Moore, Todd W.

2017-02-01

More tornadoes are produced per year in the United States than in any other country, and these tornadoes have produced tremendous losses of life and property. Understanding how tornado activity will respond to climate change is important if we wish to prepare for future changes. Trends in various tornado and tornado day characteristics, including their annual frequencies, their temporal variability, and their spatial distributions, have been reported in the past few years. This study contributes to this body of literature by further analyzing the temporal and spatial characteristics of tornado days in the United States. The analyses performed in this study support previously reported findings in addition to providing new perspectives, including that the temporal trends are observed only in low-frequency and high-frequency tornado days and that the eastward shift in tornado activity is produced, in part, by the increasing number of high-frequency tornado days, which tend to occur to the east of the traditionally depicted tornado alley in the Great Plains.

Concentrations and trends of Perfluorinated chemicals in potential indoor sources from 2007 through 2011 in the US

EPA Science Inventory

Certain perfluorinated chemicals in consumer products have been associated with developmental toxicity and other adverse health effects. Temporal trends in the concentrations of selected perfluorinated chemicals (PFCs), including perfluorooctanoic acid (PFOA) and other perfluoroc...

Analysis of European ozone trends in the period 1995-2014

NASA Astrophysics Data System (ADS)

Yan, Yingying; Pozzer, Andrea; Ojha, Narendra; Lin, Jintai; Lelieveld, Jos

2018-04-01

Surface-based measurements from the EMEP and Airbase networks are used to estimate the changes in surface ozone levels during the 1995-2014 period over Europe. We find significant ozone enhancements (0.20-0.59 µg m-3 yr-1 for the annual means; P-value < 0.01 according to an F-test) over the European suburban and urban stations during 1995-2012 based on the Airbase sites. For European background ozone observed at EMEP sites, it is shown that a significantly decreasing trend in the 95th percentile ozone concentrations has occurred, especially at noon (0.9 µg m-3 yr-1; P-value < 0.01), while the 5th percentile ozone concentrations continued to increase with a trend of 0.3 µg m-3 yr-1 (P-value < 0.01) during the study period. With the help of numerical simulations performed with the global chemistry-climate model EMAC, the importance of anthropogenic emissions changes in determining these changes over background sites are investigated. The EMAC model is found to successfully capture the observed temporal variability in mean ozone concentrations, as well as the contrast in the trends of 95th and 5th percentile ozone over Europe. Sensitivity simulations and statistical analysis show that a decrease in European anthropogenic emissions had contrasting effects on surface ozone trends between the 95th and 5th percentile levels and that background ozone levels have been influenced by hemispheric transport, while climate variability generally regulated the inter-annual variations of surface ozone in Europe.

Intercepting moving targets: does memory from practice in a specific condition of target displacement affect movement timing?

PubMed

de Azevedo Neto, Raymundo Machado; Teixeira, Luis Augusto

2011-05-01

This investigation aimed at assessing the extent to which memory from practice in a specific condition of target displacement modulates temporal errors and movement timing of interceptive movements. We compared two groups practicing with certainty of future target velocity either in unchanged target velocity or in target velocity decrease. Following practice, both experimental groups were probed in the situations of unchanged target velocity and target velocity decrease either under the context of certainty or uncertainty about target velocity. Results from practice showed similar improvement of temporal accuracy between groups, revealing that target velocity decrease did not disturb temporal movement organization when fully predictable. Analysis of temporal errors in the probing trials indicated that both groups had higher timing accuracy in velocity decrease in comparison with unchanged velocity. Effect of practice was detected by increased temporal accuracy of the velocity decrease group in situations of decreased velocity; a trend consistent with the expected effect of practice was observed for temporal errors in the unchanged velocity group and in movement initiation at a descriptive level. An additional point of theoretical interest was the fast adaptation in both groups to a target velocity pattern different from that practiced. These points are discussed under the perspective of integration of vision and motor control by means of an internal forward model of external motion.

Comparison of Salmonella enteritidis phage types isolated from layers and humans in Belgium in 2005.

PubMed

Welby, Sarah; Imberechts, Hein; Riocreux, Flavien; Bertrand, Sophie; Dierick, Katelijne; Wildemauwe, Christa; Hooyberghs, Jozef; Van der Stede, Yves

2011-08-01

The aim of this study was to investigate the available results for Belgium of the European Union coordinated monitoring program (2004/665 EC) on Salmonella in layers in 2005, as well as the results of the monthly outbreak reports of Salmonella Enteritidis in humans in 2005 to identify a possible statistical significant trend in both populations. Separate descriptive statistics and univariate analysis were carried out and the parametric and/or non-parametric hypothesis tests were conducted. A time cluster analysis was performed for all Salmonella Enteritidis phage types (PTs) isolated. The proportions of each Salmonella Enteritidis PT in layers and in humans were compared and the monthly distribution of the most common PT, isolated in both populations, was evaluated. The time cluster analysis revealed significant clusters during the months May and June for layers and May, July, August, and September for humans. PT21, the most frequently isolated PT in both populations in 2005, seemed to be responsible of these significant clusters. PT4 was the second most frequently isolated PT. No significant difference was found for the monthly trend evolution of both PT in both populations based on parametric and non-parametric methods. A similar monthly trend of PT distribution in humans and layers during the year 2005 was observed. The time cluster analysis and the statistical significance testing confirmed these results. Moreover, the time cluster analysis showed significant clusters during the summer time and slightly delayed in time (humans after layers). These results suggest a common link between the prevalence of Salmonella Enteritidis in layers and the occurrence of the pathogen in humans. Phage typing was confirmed to be a useful tool for identifying temporal trends.

Sudden cardiac death: epidemiology and risk factors

PubMed Central

Adabag, A. Selcuk; Luepker, Russell V.; Roger, Véronique L.; Gersh, Bernard J.

2016-01-01

Sudden cardiac death (SCD) is an important public-health problem with multiple etiologies, risk factors, and changing temporal trends. Substantial progress has been made over the past few decades in identifying markers that confer increased SCD risk at the population level. However, the quest for predicting the high-risk individual who could be a candidate for an implantable cardioverter-defibrillator, or other therapy, continues. In this article, we review the incidence, temporal trends, and triggers of SCD, and its demographic, clinical, and genetic risk factors. We also discuss the available evidence supporting the use of public-access defibrillators. PMID:20142817

Can data from disparate long-term fish monitoring programs be used to increase our understanding of regional and continental trends in large river assemblages?

USGS Publications Warehouse

Counihan, Timothy D.; Waite, Ian R.; Casper, Andrew F.; Ward, David L.; Sauer, Jennifer S.; Irwin, Elise R.; Chapman, Colin G.; Ickes, Brian; Paukert, Craig P.; Kosovich, John J.; Bayer, Jennifer M.

2018-01-01

Understanding trends in the diverse resources provided by large rivers will help balance tradeoffs among stakeholders and inform strategies to mitigate the effects of landscape scale stressors such as climate change and invasive species. Absent a cohesive coordinated effort to assess trends in important large river resources, a logical starting point is to assess our ability to draw inferences from existing efforts. In this paper, we use a common analytical framework to analyze data from five disparate fish monitoring programs to better understand the nature of spatial and temporal trends in large river fish assemblages. We evaluated data from programs that monitor fishes in the Colorado, Columbia, Illinois, Mississippi, and Tallapoosa rivers using non-metric dimensional scaling ordinations and associated tests to evaluate trends in fish assemblage structure and native fish biodiversity. Our results indicate that fish assemblages exhibited significant spatial and temporal trends in all five of the rivers. We also document native species diversity trends that were variable within and between rivers and generally more evident in rivers with higher species richness and programs of longer duration. We discuss shared and basin-specific landscape level stressors. Having a basic understanding of the nature and extent of trends in fish assemblages is a necessary first step towards understanding factors affecting biodiversity and fisheries in large rivers.

Can data from disparate long-term fish monitoring programs be used to increase our understanding of regional and continental trends in large river assemblages?

PubMed Central

Waite, Ian R.; Casper, Andrew F.; Ward, David L.; Sauer, Jennifer S.; Irwin, Elise R.; Chapman, Colin G.; Ickes, Brian S.; Paukert, Craig P.; Kosovich, John J.; Bayer, Jennifer M.

2018-01-01

Understanding trends in the diverse resources provided by large rivers will help balance tradeoffs among stakeholders and inform strategies to mitigate the effects of landscape scale stressors such as climate change and invasive species. Absent a cohesive coordinated effort to assess trends in important large river resources, a logical starting point is to assess our ability to draw inferences from existing efforts. In this paper, we use a common analytical framework to analyze data from five disparate fish monitoring programs to better understand the nature of spatial and temporal trends in large river fish assemblages. We evaluated data from programs that monitor fishes in the Colorado, Columbia, Illinois, Mississippi, and Tallapoosa rivers using non-metric dimensional scaling ordinations and associated tests to evaluate trends in fish assemblage structure and native fish biodiversity. Our results indicate that fish assemblages exhibited significant spatial and temporal trends in all five of the rivers. We also document native species diversity trends that were variable within and between rivers and generally more evident in rivers with higher species richness and programs of longer duration. We discuss shared and basin-specific landscape level stressors. Having a basic understanding of the nature and extent of trends in fish assemblages is a necessary first step towards understanding factors affecting biodiversity and fisheries in large rivers. PMID:29364953

Is it appropriate to composite fish samples for mercury trend monitoring and consumption advisories?

PubMed

Gandhi, Nilima; Bhavsar, Satyendra P; Gewurtz, Sarah B; Drouillard, Ken G; Arhonditsis, George B; Petro, Steve

2016-03-01

Monitoring mercury levels in fish can be costly because variation by space, time, and fish type/size needs to be captured. Here, we explored if compositing fish samples to decrease analytical costs would reduce the effectiveness of the monitoring objectives. Six compositing methods were evaluated by applying them to an existing extensive dataset, and examining their performance in reproducing the fish consumption advisories and temporal trends. The methods resulted in varying amount (average 34-72%) of reductions in samples, but all (except one) reproduced advisories very well (96-97% of the advisories did not change or were one category more restrictive compared to analysis of individual samples). Similarly, the methods performed reasonably well in recreating temporal trends, especially when longer-term and frequent measurements were considered. The results indicate that compositing samples within 5cm fish size bins or retaining the largest/smallest individuals and compositing in-between samples in batches of 5 with decreasing fish size would be the best approaches. Based on the literature, the findings from this study are applicable to fillet, muscle plug and whole fish mercury monitoring studies. The compositing methods may also be suitable for monitoring Persistent Organic Pollutants (POPs) in fish. Overall, compositing fish samples for mercury monitoring could result in a substantial savings (approximately 60% of the analytical cost) and should be considered in fish mercury monitoring, especially in long-term programs or when study cost is a concern. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Arctic marine mammal population status, sea ice habitat loss, and conservation recommendations for the 21st century

PubMed Central

Stern, Harry; Kovacs, Kit M.; Lowry, Lloyd; Moore, Sue E.; Regehr, Eric V.; Ferguson, Steven H.; Wiig, Øystein; Boveng, Peter; Angliss, Robyn P.; Born, Erik W.; Litovka, Dennis; Quakenbush, Lori; Lydersen, Christian; Vongraven, Dag; Ugarte, Fernando

2015-01-01

Abstract Arctic marine mammals (AMMs) are icons of climate change, largely because of their close association with sea ice. However, neither a circumpolar assessment of AMM status nor a standardized metric of sea ice habitat change is available. We summarized available data on abundance and trend for each AMM species and recognized subpopulation. We also examined species diversity, the extent of human use, and temporal trends in sea ice habitat for 12 regions of the Arctic by calculating the dates of spring sea ice retreat and fall sea ice advance from satellite data (1979–2013). Estimates of AMM abundance varied greatly in quality, and few studies were long enough for trend analysis. Of the AMM subpopulations, 78% (61 of 78) are legally harvested for subsistence purposes. Changes in sea ice phenology have been profound. In all regions except the Bering Sea, the duration of the summer (i.e., reduced ice) period increased by 5–10 weeks and by >20 weeks in the Barents Sea between 1979 and 2013. In light of generally poor data, the importance of human use, and forecasted environmental changes in the 21st century, we recommend the following for effective AMM conservation: maintain and improve comanagement by local, federal, and international partners; recognize spatial and temporal variability in AMM subpopulation response to climate change; implement monitoring programs with clear goals; mitigate cumulative impacts of increased human activity; and recognize the limits of current protected species legislation. PMID:25783745

The effect of drinking water contaminated with perfluoroalkyl substances on a 10-year longitudinal trend of plasma levels in an elderly Uppsala cohort.

PubMed

Stubleski, Jordan; Salihovic, Samira; Lind, P Monica; Lind, Lars; Dunder, Linda; McCleaf, Philip; Eurén, Karin; Ahrens, Lutz; Svartengren, Magnus; van Bavel, Bert; Kärrman, Anna

2017-11-01

In 2012, drinking water contaminated with per- and polyfluoroalkyl substances (PFASs), foremost perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) at levels over 20ng/L and 40ng/L, respectively, was confirmed in Uppsala, Sweden. We assessed how a longitudinally sampled cohort's temporal trend in PFAS plasma concentration was influenced by their residential location and determined the plausible association or disparity between the PFASs detected in the drinking water and the trend in the study cohort. The Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) cohort provided plasma samples three times from 2001 to 2014. Individuals maintaining the same zip code throughout the study (n = 399) were divided into a reference (no known PFAS exposure), low, intermediate and high exposure area depending on the proportion of contaminated drinking water received. Eight PFASs detected in the majority (75%) of the cohort's plasma samples were evaluated for significant changes in temporal PFAS concentrations using a random effects (mixed) model. PFHxS plasma concentrations continued to significantly increase in individuals living in areas receiving the largest percentage of contaminated drinking water (p < 0.0001), while PFOS showed an overall decrease. The temporal trend of other PFAS plasma concentrations did not show an association to the quality of drinking water received. The distribution of contaminated drinking water had a direct effect on the trend in PFHxS plasma levels among the different exposure groups, resulting in increased concentrations over time, especially in the intermediate and high exposure areas. PFOS and the remaining PFASs did not show the same relationship, suggesting other sources of exposure influenced these PFAS plasma trends. Copyright © 2017 Elsevier Inc. All rights reserved.

Spatial and temporal variability of fluoride concentrations in groundwater resources of Larestan and Gerash regions in Iran from 2003 to 2010.

PubMed

Amini, Hassan; Haghighat, Gholam Ali; Yunesian, Masud; Nabizadeh, Ramin; Mahvi, Amir Hossein; Dehghani, Mohammad Hadi; Davani, Rahim; Aminian, Abd-Rasool; Shamsipour, Mansour; Hassanzadeh, Naser; Faramarzi, Hossein; Mesdaghinia, Alireza

2016-02-01

There is discrepancy about intervals of fluoride monitoring in groundwater resources by Iranian authorities. Spatial and temporal variability of fluoride in groundwater resources of Larestan and Gerash regions in Iran were analyzed from 2003 to 2010 using a geospatial information system and the Mann-Kendall trend test. The mean concentrations of fluoride for the 8-year period in the eight cities and 31 villages were 1.6 and 2.0 mg/l, respectively; the maximum values were 2.4 and 3.8 mg/l, respectively. Spatial, temporal, and spatiotemporal variability of fluoride in overall groundwater resources were relatively constant over the years. However, results of the Mann-Kendall trend test revealed a monotonic trend in the time series of one city and 11 villages for the 8-year period. Specifically, one city and three villages showed positive significant Kendall's Tau values, suggesting an upward trend in fluoride concentrations over the 8-year period. In contrast, seven villages displayed negative significant Kendall's Tau values, arguing for a downward trend in fluoride concentrations over the years. From 2003 to 2010, approximately 52 % of the Larestan and Gerash areas have had fluoride concentrations above the maximum permissible Iranian drinking water standard fluoride level (1.4 mg/l), and about 116,000 people were exposed to such excess amounts. Therefore, our study supports for a close monitoring of fluoride concentrations from health authorities in monthly intervals, especially in villages and cities that showed positive trend in fluoride concentrations. Moreover, we recommend simultaneous implementation of cost-effective protective measures or interventions until a standard fluoride level is achieved.

Temporal Trends in Clinical and Pathological Characteristics for Men Undergoing Radical Prostatectomy Between 1995 and 2013 at Rigshospitalet, Copenhagen, Denmark, and Stanford University Hospital, United States.

PubMed

Loft, Mathias Dyrberg; Berg, Kasper Drimer; Kjaer, Andreas; Iversen, Peter; Ferrari, Michelle; Zhang, Chiyuan A; Brasso, Klaus; Brooks, James D; Røder, Martin Andreas

2017-09-06

To analyze how prostate-specific antigen (PSA) screening and practice patterns has affected trends in tumor characteristics in men undergoing radical prostatectomy (RP) in the United States and Denmark. Unlike in the United States, PSA screening has not been recommended in Denmark. We performed an observational register study using pre- and postoperative data on 2168 Danish patients from Rigshospitalet, Copenhagen, Denmark, and 2236 patients from Stanford University Hospital, Stanford, CA, who underwent RP between 1995 and 2013. Patients were stratified according to Cancer of the Prostate Risk Assessment-Postsurgical (CAPRA-S) risk groups and D'Amico risk classification and were clustered into 4 time periods (1995-1999, 2000-2004, 2005-2009, and 2010-2013). Temporal trends in the proportions of patients of a given variable at the 2 institutions were evaluated with Cochran-Armitage test for trends and chi-square testing. A total of 4404 patients were included. Temporal changes in preoperative PSA, age, grade, and stage was found in both cohorts. Median preoperative PSA declined in both cohorts, while median age increased, with the Danish cohort showing the greatest changes in both PSA and age. In both cohorts, there was a trend for higher-risk preoperative features before RP over time. In 2010-2013, 27.7% and 21.8% of the patients were in the D'Amico high-risk group at Copenhagen and Stanford, respectively. Despite recommendation against PSA screening in Denmark, Danish men undergoing RP at Rigshospitalet to a considerable extent now resemble American men undergoing RP at Stanford. At both sites, there is continued trend to reduce the number of men undergoing RP for low-risk prostate cancer. Copyright © 2017 Elsevier Inc. All rights reserved.

Spatial and Temporal Analysis of Eruption Locations, Compositions, and Styles in Northern Harrat Rahat, Kingdom of Saudi Arabia

NASA Astrophysics Data System (ADS)

Dietterich, H. R.; Stelten, M. E.; Downs, D. T.; Champion, D. E.

2017-12-01

Harrat Rahat is a predominantly mafic, 20,000 km2 volcanic field in western Saudi Arabia with an elongate volcanic axis extending 310 km north-south. Prior mapping suggests that the youngest eruptions were concentrated in northernmost Harrat Rahat, where our new geologic mapping and geochronology reveal >300 eruptive vents with ages ranging from 1.2 Ma to a historic eruption in 1256 CE. Eruption compositions and styles vary spatially and temporally within the volcanic field, where extensive alkali basaltic lavas dominate, but more evolved compositions erupted episodically as clusters of trachytic domes and small-volume pyroclastic flows. Analysis of vent locations, compositions, and eruption styles shows the evolution of the volcanic field and allows assessment of the spatio-temporal probabilities of vent opening and eruption styles. We link individual vents and fissures to eruptions and their deposits using field relations, petrography, geochemistry, paleomagnetism, and 40Ar/39Ar and 36Cl geochronology. Eruption volumes and deposit extents are derived from geologic mapping and topographic analysis. Spatial density analysis with kernel density estimation captures vent densities of up to 0.2 %/km2 along the north-south running volcanic axis, decaying quickly away to the east but reaching a second, lower high along a secondary axis to the west. Temporal trends show slight younging of mafic eruption ages to the north in the past 300 ka, as well as clustered eruptions of trachytes over the past 150 ka. Vent locations, timing, and composition are integrated through spatial probability weighted by eruption age for each compositional range to produce spatio-temporal models of vent opening probability. These show that the next mafic eruption is most probable within the north end of the main (eastern) volcanic axis, whereas more evolved compositions are most likely to erupt within the trachytic centers further to the south. These vent opening probabilities, combined with corresponding eruption properties, can be used as the basis for lava flow and tephra fall hazard maps.

Spatial-temporal consistency between gross primary productivity and solar-induced chlorophyll fluorescence of vegetation in China during 2007-2014

NASA Astrophysics Data System (ADS)

Ma, J.; Xiao, X.; Zhang, Y.; Chen, B.; Zhao, B.

2017-12-01

Great significance exists in accurately estimating spatial-temporal patterns of gross primary production (GPP) because of its important role in global carbon cycle. Satellite-based light use efficiency (LUE) models are regarded as an efficient tool in simulating spatially time-sires GPP. However, the estimation of the accuracy of GPP simulations from LUE at both spatial and temporal scales is still a challenging work. In this study, we simulated GPP of vegetation in China during 2007-2014 using a LUE model (Vegetation Photosynthesis Model, VPM) based on MODIS (moderate-resolution imaging spectroradiometer) images of 8-day temporal and 500-m spatial resolutions and NCEP (National Center for Environmental Prediction) climate data. Global Ozone Monitoring Instrument 2 (GOME-2) solar-induced chlorophyll fluorescence (SIF) data were used to compare with VPM simulated GPP (GPPVPM) temporally and spatially using linear correlation analysis. Significant positive linear correlations exist between monthly GPPVPM and SIF data over both single year (2010) and multiple years (2007-2014) in China. Annual GPPVPM is significantly positive correlated with SIF (R2>0.43) spatially for all years during 2007-2014 and all seasons in 2010 (R2>0.37). GPP dynamic trends is high spatial-temporal heterogeneous in China during 2007-2014. The results of this study indicate that GPPVPM is temporally and spatially in line with SIF data, and space-borne SIF data have great potential in validating and parameterizing GPP estimation of LUE-based models.

Historic changes in fish assemblage structure in midwestern nonwadeable rivers

USGS Publications Warehouse

Parks, Timothy P.; Quist, Michael C.; Pierce, Clay L.

2014-01-01

Historical change in fish assemblage structure was evaluated in the mainstems of the Des Moines, Iowa, Cedar, Wapsipinicon, and Maquoketa rivers, in Iowa. Fish occurrence data were compared in each river between historical and recent time periods to characterize temporal changes among 126 species distributions and assess spatiotemporal patterns in faunal similarity. A resampling procedure was used to estimate species occurrences in rivers during each assessment period and changes in species occurrence were summarized. Spatiotemporal shifts in species composition were analyzed at the river and river section scale using cluster analysis, pairwise Jaccard's dissimilarities, and analysis of multivariate beta dispersion. The majority of species exhibited either increases or declines in distribution in all rivers with the exception of several “unknown” or inconclusive trends exhibited by species in the Maquoketa River. Cluster analysis identified temporal patterns of similarity among fish assemblages in the Des Moines, Cedar, and Iowa rivers within the historical and recent assessment period indicating a significant change in species composition. Prominent declines of backwater species with phytophilic spawning strategies contributed to assemblage changes occurring across river systems.

Multivariate Statistical Analysis of Water Quality data in Indian River Lagoon, Florida

NASA Astrophysics Data System (ADS)

Sayemuzzaman, M.; Ye, M.

2015-12-01

The Indian River Lagoon, is part of the longest barrier island complex in the United States, is a region of particular concern to the environmental scientist because of the rapid rate of human development throughout the region and the geographical position in between the colder temperate zone and warmer sub-tropical zone. Thus, the surface water quality analysis in this region always brings the newer information. In this present study, multivariate statistical procedures were applied to analyze the spatial and temporal water quality in the Indian River Lagoon over the period 1998-2013. Twelve parameters have been analyzed on twelve key water monitoring stations in and beside the lagoon on monthly datasets (total of 27,648 observations). The dataset was treated using cluster analysis (CA), principle component analysis (PCA) and non-parametric trend analysis. The CA was used to cluster twelve monitoring stations into four groups, with stations on the similar surrounding characteristics being in the same group. The PCA was then applied to the similar groups to find the important water quality parameters. The principal components (PCs), PC1 to PC5 was considered based on the explained cumulative variances 75% to 85% in each cluster groups. Nutrient species (phosphorus and nitrogen), salinity, specific conductivity and erosion factors (TSS, Turbidity) were major variables involved in the construction of the PCs. Statistical significant positive or negative trends and the abrupt trend shift were detected applying Mann-Kendall trend test and Sequential Mann-Kendall (SQMK), for each individual stations for the important water quality parameters. Land use land cover change pattern, local anthropogenic activities and extreme climate such as drought might be associated with these trends. This study presents the multivariate statistical assessment in order to get better information about the quality of surface water. Thus, effective pollution control/management of the surface waters can be undertaken.

Solute Transport Dynamics in a Large Hyporheic Corridor System

NASA Astrophysics Data System (ADS)

Zachara, J. M.; Chen, X.; Murray, C. J.; Shuai, P.; Rizzo, C.; Song, X.; Dai, H.

2016-12-01

A hyporheic corridor is an extended zone of groundwater surface water-interaction that occurs within permeable aquifer sediments in hydrologic continuity with a river. These systems are dynamic and tightly coupled to river stage variations that may occur over variable time scales. Here we describe the behavior of a persistent uranium (U) contaminant plume that exists within the hyporheic corridor of a large, managed river system - the Columbia River. Temporally dense monitoring data were collected for a two year period from wells located within the plume at varying distances up to 400 m from the river shore. Groundwater U originates from desorption of residual U in the lower vadose zone during periods of high river stage and associated elevated water table. U is weakly adsorbed to aquifer sediments because of coarse texture, and along with specific conductance, serves as a tracer of vadose zone source terms, solute transport pathways, and groundwater-surface water mixing. Complex U concentration and specific conductance trends were observed for all wells that varied with distance from the river shoreline and the river hydrograph, although trends for each well were generally repeatable for each year during the monitoring period. Statistical clustering analysis was used to identify four groups of wells that exhibited common trends in dissolved U and specific conductance. A flow and reactive transport code, PFLOTRAN, was implemented within a hydrogeologic model of the groundwater-surface water interaction zone to provide insights on hydrologic processes controlling monitoring trends and cluster behavior. The hydrogeologic model was informed by extensive subsurface characterization, with the spatially variable topography of a basal aquitard being one of several key parameters. Numerical tracer experiments using PFLOTRAN revealed the presence of temporally complex flow trajectories, spatially variable domains of groundwater - river water mixing, and locations of enhanced groundwater - river exchange that helped to explain monitoring trends. Observations and modeling results are integrated into a conceptual model of this highly complex and dynamic system with applicability to hyporheic corridor systems elsewhere.

Investigation of Spatial and Temporal Trends in Water Quality in Daya Bay, South China Sea

PubMed Central

Wu, Mei-Lin; Wang, You-Shao; Dong, Jun-De; Sun, Cui-Ci; Wang, Yu-Tu; Sun, Fu-Lin; Cheng, Hao

2011-01-01

The objective is to identify the spatial and temporal variability of the hydrochemical quality of the water column in a subtropical coastal system, Daya Bay, China. Water samples were collected in four seasons at 12 monitoring sites. The Southeast Asian monsoons, northeasterly from October to the next April and southwesterly from May to September have also an important influence on water quality in Daya Bay. In the spatial pattern, two groups have been identified, with the help of multidimensional scaling analysis and cluster analysis. Cluster I consisted of the sites S3, S8, S10 and S11 in the west and north coastal parts of Daya Bay. Cluster I is mainly related to anthropogenic activities such as fish-farming. Cluster II consisted of the rest of the stations in the center, east and south parts of Daya Bay. Cluster II is mainly related to seawater exchange from South China Sea. PMID:21776234

Nutrients and the Great Lakes Nearshore, Circa 2002-2007

EPA Science Inventory

Nearshore nutrient impressions were largely limited to observations of local spatial trends from a few site-specific studies and some temporal trends at a set of Canadian water intake locations (later summarized in Nicholls et al. 1999). Lacking a systematic information base fo...

Daily MODIS data trends of hurricane-induced forest impact and early recovery

USGS Publications Warehouse

Ramsey, Elijah W.; Spruce, Joseph; Rangoonwala, Amina; Suzuoki, Yukihiro; Smoot, James; Gasser, Jerry; Bannister, Terri

2011-01-01

We studied the use of daily satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors to assess wetland forest damage and recovery from Hurricane Katrina (29 August 2005 landfall). Processed MODIS daily vegetation index (VI) trends were consistent with previously determined impact and recovery patterns provided by the "snapshot" 25 m Landsat Thematic Mapper optical and RADARSAT-1 synthetic aperture radar satellite data. Phenological trends showed high 2004 and 2005 pre-hurricane temporal correspondence within bottomland hardwood forest communities, except during spring green-up, and temporal dissimilarity between these hardwoods and nearby cypress-tupelo swamp forests (Taxodium distichum [baldcypress] and Nyssa aquatica [water tupelo]). MODIS VI trend analyses established that one year after impact, cypress-tupelo and lightly impacted hardwood forests had recovered to near pre-hurricane conditions. In contrast, canopy recovery lagged in the moderately and severely damaged hardwood forests, possibly reflecting regeneration of pre-hurricane species and stand-level replacement by invasive trees.

Temporal effects in trend prediction: identifying the most popular nodes in the future.

PubMed

Zhou, Yanbo; Zeng, An; Wang, Wei-Hong

2015-01-01

Prediction is an important problem in different science domains. In this paper, we focus on trend prediction in complex networks, i.e. to identify the most popular nodes in the future. Due to the preferential attachment mechanism in real systems, nodes' recent degree and cumulative degree have been successfully applied to design trend prediction methods. Here we took into account more detailed information about the network evolution and proposed a temporal-based predictor (TBP). The TBP predicts the future trend by the node strength in the weighted network with the link weight equal to its exponential aging. Three data sets with time information are used to test the performance of the new method. We find that TBP have high general accuracy in predicting the future most popular nodes. More importantly, it can identify many potential objects with low popularity in the past but high popularity in the future. The effect of the decay speed in the exponential aging on the results is discussed in detail.

Temporal Effects in Trend Prediction: Identifying the Most Popular Nodes in the Future

PubMed Central

Zhou, Yanbo; Zeng, An; Wang, Wei-Hong

2015-01-01

Prediction is an important problem in different science domains. In this paper, we focus on trend prediction in complex networks, i.e. to identify the most popular nodes in the future. Due to the preferential attachment mechanism in real systems, nodes’ recent degree and cumulative degree have been successfully applied to design trend prediction methods. Here we took into account more detailed information about the network evolution and proposed a temporal-based predictor (TBP). The TBP predicts the future trend by the node strength in the weighted network with the link weight equal to its exponential aging. Three data sets with time information are used to test the performance of the new method. We find that TBP have high general accuracy in predicting the future most popular nodes. More importantly, it can identify many potential objects with low popularity in the past but high popularity in the future. The effect of the decay speed in the exponential aging on the results is discussed in detail. PMID:25806810

Spatial patterns and temporal trends in mercury concentrations, precipitation depths, and mercury wet deposition in the North American Great Lakes region, 2002-2008

USGS Publications Warehouse

Risch, Martin R.; Gay, David A.; Fowler, Kathleen K.; Keeler, Gerard J.; Backus, Sean M.; Blanchard, Pierrette; Barres, James A.; Dvonch, J. Timothy

2012-01-01

Annual and weekly mercury (Hg) concentrations, precipitation depths, and Hg wet deposition in the Great Lakes region were analyzed by using data from 5 monitoring networks in the USA and Canada for a 2002-2008 study period. High-resolution maps of calculated annual data, 7-year mean data, and net interannual change for the study period were prepared to assess spatial patterns. Areas with 7-year mean annual Hg concentrations higher than the 12 ng per liter water-quality criterion were mapped in 4 states. Temporal trends in measured weekly data were determined statistically. Monitoring sites with significant 7-year trends in weekly Hg wet deposition were spatially separated and were not sites with trends in weekly Hg concentration. During 2002-2008, Hg wet deposition was found to be unchanged in the Great Lakes region and its subregions. Any small decreases in Hg concentration apparently were offset by increases in precipitation.

Bi-phasic trends in mercury concentrations in blood of Wisconsin common loons during 1992–2010

USGS Publications Warehouse

Meyer, Michael W.; Rasmussen, Paul W.; Watras, Carl J.; Fevold, Brick M.; Kenow, Kevin P.

2011-01-01

Wisconsin Department of Natural Resources (WDNR) assessed the ecological risk of mercury (Hg) in aquatic systems by monitoring common loon (Gavia immer) population dynamics and blood Hg concentrations. We report temporal trends in blood Hg concentrations based on 334 samples collected from adults recaptured in subsequent years (resampled 2-9 times) and from 421 blood samples of chicks collected at lakes resampled 2-8 times 1992-2010.. Temporal trends were identified with generalized additive mixed effects models (GAMMs) and mixed effects models to account for the potential lack of independence among observations from the same loon or same lake. Trend analyses indicated that Hg concentrations in the blood of Wisconsin loons declined over the period 1992-2000, and increased during 2002-2010, but not to the level observed in the early 1990s. The best fitting linear mixed effects model included separate trends for the two time periods. The estimated trend in Hg concentration among the adult loon population during 1992-2000 was -2.6% per year and the estimated trend during 2002-2010 was +1.8% per year; chick blood Hg concentrations decreased by -6.5% per year during 1992-2000, but increased 1.8% per year during 2002-2010. This bi-phasic pattern is similar to trends observed for concentrations of methylmercury (meHg) and SO4 in lake water of a well studied seepage lake (Little Rock Lake, Vilas County) within our study area. A cause-effect relationship between these independent trends is hypothesized.

Temporal trends in motor vehicle fatalities in the United States, 1968 to 2010 - a joinpoint regression analysis.

PubMed

Bandi, Priti; Silver, Diana; Mijanovich, Tod; Macinko, James

2015-12-01

In the past 40 years, a variety of factors might have impacted motor vehicle (MV) fatality trends in the US, including public health policies, engineering innovations, trauma care improvements, etc. These factors varied in their timing across states/localities, and many were targeted at particular population subgroups. In order to identify and quantify differential rates of change over time and differences in trend patterns between population subgroups, this study employed a novel analytic method to assess temporal trends in MV fatalities between 1968 and 2010, by age group and sex. Cause-specific MV fatality data from traffic injuries between 1968 and 2010, based on death certificates filed in the 50 states, and DC were obtained from Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research (CDC WONDER). Long-term (1968 to 2010) and short-term (log-linear piecewise segments) trends in fatality rates were compared for males and females overall and in four separate age groups using joinpoint regression. MV fatalities declined on average by 2.4% per year in males and 2.2% per year in females between 1968 and 2010, with significant declines observed in all age groups and in both sexes. In males overall and those 25 to 64 years, sharp declines between 1968 and mid-to-late 1990s were followed by a stalling until the mid-2000s, but rates in females experienced a long-term steady decline of a lesser magnitude than males during this time. Trends in those aged <1 to 14 years and 15 to 24 years were mostly steady over time, but males had a larger decline than females in the latter age group between 1968 and the mid-2000s. In ages 65+, short-term trends were similar between sexes. Despite significant long-term declines in MV fatalities, the application of Joinpoint Regression found that progress in young adult and middle-aged adult males stalled in recent decades and rates in males declined relatively more than in females in certain age groups. Future research is needed to establish the causes of these observed trends, including the potential role of contemporaneous MV-related policies and their repeal. Such research is needed in order to better inform the design and evaluation of future population interventions addressing MV fatalities nationally.

Recent trends in paralytic shellfish toxins in Puget Sound, relationships to climate, and capacity for prediction of toxic events

Treesearch

Stephanie K. Moore; Nathan J. Mantua; Barbara M. Hickey; Vera L. Trainer

2009-01-01

Temporal and spatial trends in paralytic shellfish toxins (PSTs) in Puget Sound shellfish and their relationships with climate are investigated using long-term monitoring data since 1957. Data are selected for trend analyses based on the sensitivity of shellfish species to PSTs and their depuration rates, and the frequency of sample collection at individual sites....

Temporal trends in water-quality constituent concentrations and annual loads of chemical constituents in Michigan watersheds, 1998–2013

USGS Publications Warehouse

Hoard, Christopher J.; Fogarty, Lisa R.; Duris, Joseph W.

2018-02-21

In 1998, the Michigan Department of Environmental Quality and the U.S. Geological Survey began the Water Chemistry Monitoring Program for select streams in the State of Michigan. Objectives of this program were to provide assistance with (1) statewide water-quality assessments, (2) the National Pollutant Discharge Elimination System permitting process, and (3) water-resource management decisions. As part of this program, water-quality data collected from 1998 to 2013 were analyzed to identify potential trends for select constituents that were sampled. Sixteen water-quality constituents were analyzed at 32 stations throughout Michigan. Trend analysis on the various water-quality data was done using either the uncensored Seasonal Kendall test or through Tobit regression. In total, 79 trends were detected in the constituents analyzed for 32 river stations sampled for the study period—53 downward trends and 26 upward trends were detected. The most prevalent trend detected throughout the State was for ammonia, with 11 downward trends and 1 upward trend estimated.In addition to trends, constituent loads were estimated for 31 stations from 2002 to 2013 for stations that were sampled 12 times per year. Loads were computed using the Autobeale load computation program, which used the Beale ratio estimator approach to estimate an annual load. Constituent loads were the largest in large watershed streams with the highest annual flows such as the Saginaw and Grand Rivers. Likewise, constituent loads were the smallest in smaller tributaries that were sampled as part of this program such as the Boardman and Thunder Bay Rivers.

Internet search trends analysis tools can provide real-time data on kidney stone disease in the United States.

PubMed

Willard, Scott D; Nguyen, Mike M

2013-01-01

To evaluate the utility of using Internet search trends data to estimate kidney stone occurrence and understand the priorities of patients with kidney stones. Internet search trends data represent a unique resource for monitoring population self-reported illness and health information-seeking behavior. The Google Insights for Search analysis tool was used to study searches related to kidney stones, with each search term returning a search volume index (SVI) according to the search frequency relative to the total search volume. SVIs for the term, "kidney stones," were compiled by location and time parameters and compared with the published weather and stone prevalence data. Linear regression analysis was performed to determine the association of the search interest score with known epidemiologic variations in kidney stone disease, including latitude, temperature, season, and state. The frequency of the related search terms was categorized by theme and qualitatively analyzed. The SVI correlated significantly with established kidney stone epidemiologic predictors. The SVI correlated with the state latitude (R-squared=0.25; P<.001), the state mean annual temperature (R-squared=0.24; P<.001), and state combined sex prevalence (R-squared=0.25; P<.001). Female prevalence correlated more strongly than did male prevalence (R-squared=0.37; P<.001, and R-squared=0.17; P=.003, respectively). The national SVI correlated strongly with the average U.S. temperature by month (R-squared=0.54; P=.007). The search term ranking suggested that Internet users are most interested in the diagnosis, followed by etiology, infections, and treatment. Geographic and temporal variability in kidney stone disease appear to be accurately reflected in Internet search trends data. Internet search trends data might have broader applications for epidemiologic and urologic research. Copyright © 2013 Elsevier Inc. All rights reserved.

Musculoskeletal disorders as underlying cause of death in 58 countries, 1986-2011: trend analysis of WHO mortality database.

PubMed

Kiadaliri, Aliasghar A; Woolf, Anthony D; Englund, Martin

2017-02-02

Due to low mortality rate of musculoskeletal disorders (MSK) less attention has been paid to MSK as underlying cause of death in the general population. The aim was to examine trend in MSK as underlying cause of death in 58 countries across globe during 1986-2011. Data on mortality were collected from the WHO mortality database and population data were obtained from the United Nations. Annual sex-specific age-standardized mortality rates (ASMR) were calculated by means of direct standardization using the WHO world standard population. We applied joinpoint regression analysis for trend analysis. Between-country disparities were examined using between-country variance and Gini coefficient. The changes in number of MSK deaths between 1986 and 2011 were decomposed using two counterfactual scenarios. The number of MSK deaths increased by 67% between 1986 and 2011 mainly due to population aging. The mean ASMR changed from 17.2 and 26.6 per million in 1986 to 18.1 and 25.1 in 2011 among men and women, respectively (median: 7.3% increase in men and 9.0% reduction in women). Declines in ASMR of 25% or more were observed for men (women) in 13 (19) countries, while corresponding increases were seen for men (women) in 25 (14) countries. In both sexes, ASMR declined during 1986-1997, then increased during 1997-2001 and again declined over 2001-2011. Despite decline over time, there were substantial between-country disparities in MSK mortality and its temporal trend. We found substantial variations in MSK mortality and its trends between countries, regions and also between sex and age groups. Promoted awareness and better management of MSK might partly explain reduction in MSK mortality, but variations across countries warrant further investigations.

Progress in the reduction of carbon monoxide levels in major urban areas in Korea.

PubMed

Kim, Ki-Hyun; Sul, Kyung-Hwa; Szulejko, Jan E; Chambers, Scott D; Feng, Xinbin; Lee, Min-Hee

2015-12-01

Long-term trends in observed carbon monoxide (CO) concentrations were analyzed in seven major South Korean cities from 1989 to 2013. Temporal trends were evident on seasonal and annual timescales, as were spatial gradients between the cities. As CO levels in the most polluted cities decreased significantly until the early 2000s, the data were arbitrarily divided into two time periods (I: 1989-2000 and II: 2001-2013) for analysis. The mean CO concentration of period II was about 50% lower than that of period I. Long-term trends of annual mean CO concentrations, examined using the Mann-Kendall (MK) method, confirm a consistent reduction in CO levels from 1989 to 2000 (period I). The abrupt reduction in CO levels was attributed to a combination of technological improvements and government administrative/regulatory initiatives (e.g., emission mitigation strategies and a gradual shift in the fuel/energy consumption mix away from coal and oil to natural gas and nuclear power). Copyright © 2015 Elsevier Ltd. All rights reserved.

Trends in prevalence of multi drug resistant tuberculosis in sub-Saharan Africa: A systematic review and meta-analysis

PubMed Central

Adamu, Aishatu L.; Galadanci, Najibah A.; Zubayr, Bashir; Odoh, Chisom N.; Aliyu, Muktar H.

2017-01-01

Background Multidrug resistant tuberculosis (MDR-TB), is an emerging public health problem in sub-Saharan Africa (SSA). This study aims to determine the trends in prevalence of MDR-TB among new TB cases in sub-Saharan Africa over two decades. Methods We searched electronic data bases and accessed all prevalence studies of MDR-TB within SSA between 2007 and 2017. We determined pooled prevalence estimates using random effects models and determined trends using meta-regression. Results Results: We identified 915 studies satisfying inclusion criteria. Cumulatively, studies reported on MDR-TB culture of 34,652 persons. The pooled prevalence of MDR-TB in new cases was 2.1% (95% CI; 1.7–2.5%). There was a non-significant decline in prevalence by 0.12% per year. Conclusion We found a low prevalence estimate of MDR-TB, and a slight temporal decline over the study period. There is a need for continuous MDR-TB surveillance among patients with TB. PMID:28945771

Changes in seasonal streamflow extremes experienced in rivers of Northwestern South America (Colombia)

NASA Astrophysics Data System (ADS)

Pierini, J. O.; Restrepo, J. C.; Aguirre, J.; Bustamante, A. M.; Velásquez, G. J.

2017-04-01

A measure of the variability in seasonal extreme streamflow was estimated for the Colombian Caribbean coast, using monthly time series of freshwater discharge from ten watersheds. The aim was to detect modifications in the streamflow monthly distribution, seasonal trends, variance and extreme monthly values. A 20-year length time moving window, with 1-year successive shiftments, was applied to the monthly series to analyze the seasonal variability of streamflow. The seasonal-windowed data were statistically fitted through the Gamma distribution function. Scale and shape parameters were computed using the Maximum Likelihood Estimation (MLE) and the bootstrap method for 1000 resample. A trend analysis was performed for each windowed-serie, allowing to detect the window of maximum absolute values for trends. Significant temporal shifts in seasonal streamflow distribution and quantiles (QT), were obtained for different frequencies. Wet and dry extremes periods increased significantly in the last decades. Such increase did not occur simultaneously through the region. Some locations exhibited continuous increases only at minimum QT.

Incidence of Appendicitis over Time: A Comparative Analysis of an Administrative Healthcare Database and a Pathology-Proven Appendicitis Registry

PubMed Central

Clement, Fiona; Zimmer, Scott; Dixon, Elijah; Ball, Chad G.; Heitman, Steven J.; Swain, Mark; Ghosh, Subrata

2016-01-01

Importance At the turn of the 21st century, studies evaluating the change in incidence of appendicitis over time have reported inconsistent findings. Objectives We compared the differences in the incidence of appendicitis derived from a pathology registry versus an administrative database in order to validate coding in administrative databases and establish temporal trends in the incidence of appendicitis. Design We conducted a population-based comparative cohort study to identify all individuals with appendicitis from 2000 to2008. Setting & Participants Two population-based data sources were used to identify cases of appendicitis: 1) a pathology registry (n = 8,822); and 2) a hospital discharge abstract database (n = 10,453). Intervention & Main Outcome The administrative database was compared to the pathology registry for the following a priori analyses: 1) to calculate the positive predictive value (PPV) of administrative codes; 2) to compare the annual incidence of appendicitis; and 3) to assess differences in temporal trends. Temporal trends were assessed using a generalized linear model that assumed a Poisson distribution and reported as an annual percent change (APC) with 95% confidence intervals (CI). Analyses were stratified by perforated and non-perforated appendicitis. Results The administrative database (PPV = 83.0%) overestimated the incidence of appendicitis (100.3 per 100,000) when compared to the pathology registry (84.2 per 100,000). Codes for perforated appendicitis were not reliable (PPV = 52.4%) leading to overestimation in the incidence of perforated appendicitis in the administrative database (34.8 per 100,000) as compared to the pathology registry (19.4 per 100,000). The incidence of appendicitis significantly increased over time in both the administrative database (APC = 2.1%; 95% CI: 1.3, 2.8) and pathology registry (APC = 4.1; 95% CI: 3.1, 5.0). Conclusion & Relevance The administrative database overestimated the incidence of appendicitis, particularly among perforated appendicitis. Therefore, studies utilizing administrative data to analyze perforated appendicitis should be interpreted cautiously. PMID:27820826

Spatiotemporal patterns of drought at various time scales in Shandong Province of Eastern China

NASA Astrophysics Data System (ADS)

Zuo, Depeng; Cai, Siyang; Xu, Zongxue; Li, Fulin; Sun, Wenchao; Yang, Xiaojing; Kan, Guangyuan; Liu, Pin

2018-01-01

The temporal variations and spatial patterns of drought in Shandong Province of Eastern China were investigated by calculating the standardized precipitation evapotranspiration index (SPEI) at 1-, 3-, 6-, 12-, and 24-month time scales. Monthly precipitation and air temperature time series during the period 1960-2012 were collected at 23 meteorological stations uniformly distributed over the region. The non-parametric Mann-Kendall test was used to explore the temporal trends of precipitation, air temperature, and the SPEI drought index. S-mode principal component analysis (PCA) was applied to identify the spatial patterns of drought. The results showed that an insignificant decreasing trend in annual total precipitation was detected at most stations, a significant increase of annual average air temperature occurred at all the 23 stations, and a significant decreasing trend in the SPEI was mainly detected at the coastal stations for all the time scales. The frequency of occurrence of extreme and severe drought at different time scales generally increased with decades; higher frequency and larger affected area of extreme and severe droughts occurred as the time scale increased, especially for the northwest of Shandong Province and Jiaodong peninsular. The spatial pattern of drought for SPEI-1 contains three regions: eastern Jiaodong Peninsular and northwestern and southern Shandong. As the time scale increased to 3, 6, and 12 months, the order of the three regions was transformed into another as northwestern Shandong, eastern Jiaodong Peninsular, and southern Shandong. For SPEI-24, the location identified by REOF1 was slightly shifted from northwestern Shandong to western Shandong, and REOF2 and REOF3 identified another two weak patterns in the south edge and north edge of Jiaodong Peninsular, respectively. The potential causes of drought and the impact of drought on agriculture in the study area have also been discussed. The temporal variations and spatial patterns of drought obtained in this study provide valuable information for water resources planning and drought disaster prevention and mitigation in Eastern China.

Temporal trends of young-of-year fishes in Lake Erie and comparison of diel sampling periods

USGS Publications Warehouse

Stapanian, M.A.; Bur, M.T.; Adams, J.V.

2007-01-01

We explored temporal trends of young-of-year (YOY) fishes caught in bottom trawl hauls at an established offshore monitoring site in Lake Erie in fall during 1961–2001. Sampling was conducted during morning, afternoon, and night in each year. Catches per hour (CPH) of alewife (Alosa pseudoharengus) YOY were relatively low and exhibited no temporal trend. This result was consistent with the species’ intolerance to Lake Erie’s adverse winter water temperatures. Gizzard shad (Dorosoma cepedianum) YOY decreased sharply after 1991, which was consistent with recent oligotrophication of the lake. Following the establishment in 1979 and rapid increase of white perch (Morone americana) YOY, white bass (Morone chrysops) and freshwater drum (Aplodinotus grunniens) YOY decreased. Trout-perch (Percopsis omiscomaycus) YOY decreased during 1986–1991, but recovered to previous levels during 1991–2001. The recovery coincided with the resurgence of mayflies (Ephemoptera) in the lake. CPH of spottail shiner (Notropis hudsonius) and emerald shiner (N. atherinoides) YOY exhibited no temporal trend between 1961 and the late 1970s to early 1980s. CPH of yellow perch (Perca flavescens) YOY decreased during 1961–1988, and walleye (Sander vitreum) YOY increased overall during the time series. These observations were consistent with published studies of adults in the region. CPH of 4 of the 10 species of YOY considered were greatest during night. CPH for walleye YOY was higher in the morning than in the afternoon, but there was no significant difference between night and morning abundances. The results suggest that (1) CPH of YOY fishes may be a useful monitoring tool for Lake Erie, and (2) offshore monitoring programs that do not include night sampling periods may underestimate recruitment for several common species.

Spatial and temporal trends and flow dynamics of glyphosate and other pesticides within an agricultural watershed in Argentina.

PubMed

Pérez, Débora J; Okada, Elena; De Gerónimo, Eduardo; Menone, Mirta L; Aparicio, Virginia C; Costa, José L

2017-12-01

In the present study, we evaluated the spatial and temporal trends of current-use pesticides in surface water and sediments as well as their relationship with hydrological stream dynamics within the agricultural watershed of El Crespo stream (Buenos Aires Province, Argentina). We sampled 2 contrasting sites: site 1 (upstream), surrounded by agricultural lands, and site 2 (downstream), surrounded by natural grasslands. Most of the applied pesticides (glyphosate, 2,4-D, atrazine, tebuconazole, and imidacloprid) were detected at high frequencies in surface water samples at both sites. However, only glyphosate and aminomethylphosphonic acid (AMPA) were present at high concentrations and had a significant spatial-temporal trend. The highest concentrations were found during spring 2014 at site 1, in association with the intense rains that occurred in that season. The fact that glyphosate and AMPA concentrations were higher than the rest of the studied compounds is closely related to the land use within the watershed, as glyphosate was the most applied herbicide during the fallow period of glyphosate-resistant crops (soybean, maize). The pesticide mixture had a significant spatial-temporal trend, reaching the highest levels during storm flow events in spring 2014. The intensive rains in spring 2014 could be the main factor influencing stream hydrology and pesticide behavior at El Crespo watershed. The estimated annual pesticide losses were 3.11 g/ha at site 1 and 0.72 g/ha at site 2. This result indicates that an attenuation process could be decreasing pesticide loads during downstream transport from site 1 to site 2. Environ Toxicol Chem 2017;36:3206-3216. © 2017 SETAC. © 2017 SETAC.

Variation of the fractal dimension anisotropy of two major Cenozoic normal fault systems over space and time around the Snake River Plain, Idaho and SW Montana

NASA Astrophysics Data System (ADS)

Davarpanah, A.; Babaie, H. A.

2012-12-01

The interaction of the thermally induced stress field of the Yellowstone hotspot (YHS) with existing Basin and Range (BR) fault blocks, over the past 17 m.y., has produced a new, spatially and temporally variable system of normal faults around the Snake River Plain (SRP) in Idaho and Wyoming-Montana area. Data about the trace of these new cross faults (CF) and older BR normal faults were acquired from a combination of satellite imageries, DEM, and USGS geological maps and databases at scales of 1:24,000, 1:100,000, 1:250,000, 1:1000, 000, and 1:2,500, 000, and classified based on their azimuth in ArcGIS 10. The box-counting fractal dimension (Db) of the BR fault traces, determined applying the Benoit software, and the anisotropy intensity (ellipticity) of the fractal dimensions, measured with the modified Cantor dust method applying the AMOCADO software, were measured in two large spatial domains (I and II). The Db and anisotropy of the cross faults were studied in five temporal domains (T1-T5) classified based on the geologic age of successive eruptive centers (12 Ma to recent) of the YHS along the eastern SRP. The fractal anisotropy of the CF system in each temporal domain was also spatially determined in the southern part (domain S1), central part (domain S2), and northern part (domain S3) of the SRP. Line (fault trace) density maps for the BR and CF polylines reveal a higher linear density (trace length per unit area) for the BR traces in the spatial domain I, and a higher linear density of the CF traces around the present Yellowstone National Park (S1T5) where most of the seismically active faults are located. Our spatio-temporal analysis reveals that the fractal dimension of the BR system in domain I (Db=1.423) is greater than that in domain II (Db=1.307). It also shows that the anisotropy of the fractal dimension in domain I is less eccentric (axial ratio: 1.242) than that in domain II (1.355), probably reflecting the greater variation in the trend of the BR system in domain I. The CF system in the S1T5 domain has the highest fractal dimension (Db=1.37) and the lowest anisotropy eccentricity (1.23) among the five temporal domains. These values positively correlate with the observed maxima on the fault trace density maps. The major axis of the anisotropy ellipses is consistently perpendicular to the average trend of the normal fault system in each domain, and therefore approximates the orientation of extension for normal faulting in each domain. This fact gives a NE-SW and NW-SE extension direction for the BR system in domains I and II, respectively. The observed NE-SW orientation of the major axes of the anisotropy ellipses in the youngest T4 and T5 temporal domains, oriented perpendicular to the mean trend of the normal faults in the these domains, suggests extension along the NE-SW direction for cross faulting in these areas. The spatial trajectories (form lines) of the minor axes of the anisotropy ellipses, and the mean trend of fault traces in the T4 and T5 temporal domains, define a large parabolic pattern about the axis of the eastern SRP, with its apex at the Yellowstone plateau.

Using spatio-temporal modeling to predict long-term exposure to black smoke at fine spatial and temporal scale

NASA Astrophysics Data System (ADS)

Dadvand, Payam; Rushton, Stephen; Diggle, Peter J.; Goffe, Louis; Rankin, Judith; Pless-Mulloli, Tanja

2011-01-01

Whilst exposure to air pollution is linked to a wide range of adverse health outcomes, assessing levels of this exposure has remained a challenge. This study reports a modeling approach for the estimation of weekly levels of ambient black smoke (BS) at residential postcodes across Northeast England (2055 km 2) over a 12 year period (1985-1996). A two-stage modeling strategy was developed using monitoring data on BS together with a range of covariates including data on traffic, population density, industrial activity, land cover (remote sensing), and meteorology. The first stage separates the temporal trend in BS for the region as a whole from within-region spatial variation and the second stage is a linear model which predicts BS levels at all locations in the region using spatially referenced covariate data as predictors and the regional predicted temporal trend as an offset. Traffic and land cover predictors were included in the final model, which predicted 70% of the spatio-temporal variation in BS across the study region over the study period. This modeling approach appears to provide a robust way of estimating exposure to BS at an inter-urban scale.

A statistical model and national data set for partioning fish-tissue mercury concentration variation between spatiotemporal and sample characteristic effects

USGS Publications Warehouse

Wente, Stephen P.

2004-01-01

Many Federal, Tribal, State, and local agencies monitor mercury in fish-tissue samples to identify sites with elevated fish-tissue mercury (fish-mercury) concentrations, track changes in fish-mercury concentrations over time, and produce fish-consumption advisories. Interpretation of such monitoring data commonly is impeded by difficulties in separating the effects of sample characteristics (species, tissues sampled, and sizes of fish) from the effects of spatial and temporal trends on fish-mercury concentrations. Without such a separation, variation in fish-mercury concentrations due to differences in the characteristics of samples collected over time or across space can be misattributed to temporal or spatial trends; and/or actual trends in fish-mercury concentration can be misattributed to differences in sample characteristics. This report describes a statistical model and national data set (31,813 samples) for calibrating the aforementioned statistical model that can separate spatiotemporal and sample characteristic effects in fish-mercury concentration data. This model could be useful for evaluating spatial and temporal trends in fishmercury concentrations and developing fish-consumption advisories. The observed fish-mercury concentration data and model predictions can be accessed, displayed geospatially, and downloaded via the World Wide Web (http://emmma.usgs.gov). This report and the associated web site may assist in the interpretation of large amounts of data from widespread fishmercury monitoring efforts.

Comparing temporal trends of organochlorines in guillemot eggs and Baltic herring: advantages and disadvantage for selecting sentinel species for environmental monitoring.

PubMed

Miller, Aroha; Nyberg, Elisabeth; Danielsson, Sara; Faxneld, Suzanne; Haglund, Peter; Bignert, Anders

2014-09-01

Within Europe, the Marine Strategy Framework Directive (MSFD) is aimed at addressing the chemical status and quality of the marine environment. One of the main goals is to achieve Good Environmental Status (GES) in the marine environment. Environmental monitoring of biota e.g., Baltic herring and guillemot eggs, is conducted annually in Sweden to follow temporal changes in environmental contaminants. To determine the suitability of guillemot eggs as a sentinel species for investigating GES, we compared temporal trends of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in these two species from single sampling sites within Sweden. Lipid content from guillemot eggs was consistently high and stable (yearly mean for >40 years, ∼12%) compared to that of herring (yearly mean for >20 years, ∼3%). A significant decreasing trend of ΣPCDD/F in TEQ WHO1998 was observed in guillemot eggs, but no trend was seen in herring. CB118 significantly decreased in both species, but in the last 10 years this decrease was not significant in herring. A number of advantages, such as high lipid content in the egg and a low coefficient of variation make guillemot suitable as a sentinel species. The advantages and disadvantages of using either guillemot eggs or Baltic herring are compared. Copyright © 2014 Elsevier Ltd. All rights reserved.

Long-term citizen-collected data reveal geographical patterns and temporal trends in lake water clarity

USGS Publications Warehouse

Lottig, Noah R.; Wagner, Tyler; Henry, Emily N.; Cheruvelil, Kendra Spence; Webster, Katherine E.; Downing, John A.; Stow, Craig A.

2014-01-01

We compiled a lake-water clarity database using publically available, citizen volunteer observations made between 1938 and 2012 across eight states in the Upper Midwest, USA. Our objectives were to determine (1) whether temporal trends in lake-water clarity existed across this large geographic area and (2) whether trends were related to the lake-specific characteristics of latitude, lake size, or time period the lake was monitored. Our database consisted of >140,000 individual Secchi observations from 3,251 lakes that we summarized per lake-year, resulting in 21,020 summer averages. Using Bayesian hierarchical modeling, we found approximately a 1% per year increase in water clarity (quantified as Secchi depth) for the entire population of lakes. On an individual lake basis, 7% of lakes showed increased water clarity and 4% showed decreased clarity. Trend direction and strength were related to latitude and median sample date. Lakes in the southern part of our study-region had lower average annual summer water clarity, more negative long-term trends, and greater inter-annual variability in water clarity compared to northern lakes. Increasing trends were strongest for lakes with median sample dates earlier in the period of record (1938–2012). Our ability to identify specific mechanisms for these trends is currently hampered by the lack of a large, multi-thematic database of variables that drive water clarity (e.g., climate, land use/cover). Our results demonstrate, however, that citizen science can provide the critical monitoring data needed to address environmental questions at large spatial and long temporal scales. Collaborations among citizens, research scientists, and government agencies may be important for developing the data sources and analytical tools necessary to move toward an understanding of the factors influencing macro-scale patterns such as those shown here for lake water clarity.

Long-Term Citizen-Collected Data Reveal Geographical Patterns and Temporal Trends in Lake Water Clarity

PubMed Central

Lottig, Noah R.; Wagner, Tyler; Norton Henry, Emily; Spence Cheruvelil, Kendra; Webster, Katherine E.; Downing, John A.; Stow, Craig A.

2014-01-01

We compiled a lake-water clarity database using publically available, citizen volunteer observations made between 1938 and 2012 across eight states in the Upper Midwest, USA. Our objectives were to determine (1) whether temporal trends in lake-water clarity existed across this large geographic area and (2) whether trends were related to the lake-specific characteristics of latitude, lake size, or time period the lake was monitored. Our database consisted of >140,000 individual Secchi observations from 3,251 lakes that we summarized per lake-year, resulting in 21,020 summer averages. Using Bayesian hierarchical modeling, we found approximately a 1% per year increase in water clarity (quantified as Secchi depth) for the entire population of lakes. On an individual lake basis, 7% of lakes showed increased water clarity and 4% showed decreased clarity. Trend direction and strength were related to latitude and median sample date. Lakes in the southern part of our study-region had lower average annual summer water clarity, more negative long-term trends, and greater inter-annual variability in water clarity compared to northern lakes. Increasing trends were strongest for lakes with median sample dates earlier in the period of record (1938–2012). Our ability to identify specific mechanisms for these trends is currently hampered by the lack of a large, multi-thematic database of variables that drive water clarity (e.g., climate, land use/cover). Our results demonstrate, however, that citizen science can provide the critical monitoring data needed to address environmental questions at large spatial and long temporal scales. Collaborations among citizens, research scientists, and government agencies may be important for developing the data sources and analytical tools necessary to move toward an understanding of the factors influencing macro-scale patterns such as those shown here for lake water clarity. PMID:24788722

Examining trends in prediabetes and its relationship with the metabolic syndrome in US adolescents, 1999-2014.

PubMed

Lee, Arthur M; Fermin, Cyrelle R; Filipp, Stephanie L; Gurka, Matthew J; DeBoer, Mark D

2017-04-01

We sought to investigate temporal trends in prediabetes prevalence among US adolescents using two definitions and evaluate relationships with obesity and a MetS-severity score. We evaluated data from 5418 non-Hispanic white, non-Hispanic black, and Hispanic adolescents aged 12-19 participating in the National Health and Nutrition Examination Survey 1999-2014 with complete data regarding MetS and hemoglobin A1c (HbA1c). Prediabetes status was defined by American Diabetes Association (ADA) criteria: fasting glucose 100-125 mg/dL or HbA1c 5.7%-6.4%. MetS severity was assessed with a MetS-severity Z-score. Prevalence of prediabetes as defined by HbA1c abnormalities significantly increased from 1999-2014, while prevalence of prediabetes as defined by fasting glucose abnormalities showed no significant temporal trend. There were variations in these trends across different racial/ethnic groups. MetS Z-score was overall more strongly correlated with HbA1c, fasting insulin, and the homeostasis model of insulin resistance than was BMI Z-score. These correlations were true in each racial/ethnic group with the exception that in non-Hispanic white adolescents, in whom the MetS Z-score was not significantly correlated with HbA1c measurements. We found conflicting findings of temporal trends of US adolescent prediabetes prevalence based on the ADA's prediabetes criteria. The increasing prevalence of prediabetes by HbA1c assessment is concerning and raises the urgency for increased awareness and appropriate measures of prediabetes status among physicians and patients.

Temporal trends in algae, benthic invertebrate, and fish assemblages in streams and rivers draining basins of varying land use in the south-central United States, 1993-2007

USGS Publications Warehouse

Miller, Matthew P.; Kennen, Jonathan G.; Mabe, Jeffrey A.; Mize, Scott V.

2012-01-01

Site-specific temporal trends in algae, benthic invertebrate, and fish assemblages were investigated in 15 streams and rivers draining basins of varying land use in the south-central United States from 1993–2007. A multivariate approach was used to identify sites with statistically significant trends in aquatic assemblages which were then tested for correlations with assemblage metrics and abiotic environmental variables (climate, water quality, streamflow, and physical habitat). Significant temporal trends in one or more of the aquatic assemblages were identified at more than half (eight of 15) of the streams in the study. Assemblage metrics and abiotic environmental variables found to be significantly correlated with aquatic assemblages differed between land use categories. For example, algal assemblages at undeveloped sites were associated with physical habitat, while algal assemblages at more anthropogenically altered sites (agricultural and urban) were associated with nutrient and streamflow metrics. In urban stream sites results indicate that streamflow metrics may act as important controls on water quality conditions, as represented by aquatic assemblage metrics. The site-specific identification of biotic trends and abiotic–biotic relations presented here will provide valuable information that can inform interpretation of continued monitoring data and the design of future studies. In addition, the subsets of abiotic variables identified as potentially important drivers of change in aquatic assemblages provide policy makers and resource managers with information that will assist in the design and implementation of monitoring programs aimed at the protection of aquatic resources.

Intelligent Performance Analysis with a Natural Language Interface

NASA Astrophysics Data System (ADS)

Juuso, Esko K.

2017-09-01

Performance improvement is taken as the primary goal in the asset management. Advanced data analysis is needed to efficiently integrate condition monitoring data into the operation and maintenance. Intelligent stress and condition indices have been developed for control and condition monitoring by combining generalized norms with efficient nonlinear scaling. These nonlinear scaling methodologies can also be used to handle performance measures used for management since management oriented indicators can be presented in the same scale as intelligent condition and stress indices. Performance indicators are responses of the process, machine or system to the stress contributions analyzed from process and condition monitoring data. Scaled values are directly used in intelligent temporal analysis to calculate fluctuations and trends. All these methodologies can be used in prognostics and fatigue prediction. The meanings of the variables are beneficial in extracting expert knowledge and representing information in natural language. The idea of dividing the problems into the variable specific meanings and the directions of interactions provides various improvements for performance monitoring and decision making. The integrated temporal analysis and uncertainty processing facilitates the efficient use of domain expertise. Measurements can be monitored with generalized statistical process control (GSPC) based on the same scaling functions.

Trend and change point analyses of annual precipitation in the Souss-Massa Region in Morocco during 1932-2010

NASA Astrophysics Data System (ADS)

Abahous, H.; Ronchail, J.; Sifeddine, A.; Kenny, L.; Bouchaou, L.

2017-11-01

In the context of an arid area such as Souss Massa Region, the availability of time series analysis of observed local data is vital to better characterize the regional rainfall configuration. In this paper, dataset of monthly precipitation collected from different local meteorological stations during 1932-2010, are quality controlled and analyzed to detect trend and change points. The temporal distribution of outliers shows an annual cycle and a decrease of their number since the 1980s. The results of the standard normal homogeneity test, penalized maximal t test, and Mann-Whitney-Pettit test show that 42% of the series are homogeneous. The analysis of annual precipitation in the region of Souss Massa during 1932-2010 shows wet conditions with a maximum between 1963 and 1965 followed by a decrease since 1973. The latter is identified as a statistically significant regional change point in Western High Atlas and Anti Atlas Mountains highlighting a decline in long-term average precipitation.

Community ecology in 3D: Tensor decomposition reveals spatio-temporal dynamics of large ecological communities

PubMed Central

Lindegren, Martin; Denker, Tim Spaanheden; Floeter, Jens; Fock, Heino O.; Sguotti, Camilla; Stäbler, Moritz; Otto, Saskia A.; Möllmann, Christian

2017-01-01

Understanding spatio-temporal dynamics of biotic communities containing large numbers of species is crucial to guide ecosystem management and conservation efforts. However, traditional approaches usually focus on studying community dynamics either in space or in time, often failing to fully account for interlinked spatio-temporal changes. In this study, we demonstrate and promote the use of tensor decomposition for disentangling spatio-temporal community dynamics in long-term monitoring data. Tensor decomposition builds on traditional multivariate statistics (e.g. Principal Component Analysis) but extends it to multiple dimensions. This extension allows for the synchronized study of multiple ecological variables measured repeatedly in time and space. We applied this comprehensive approach to explore the spatio-temporal dynamics of 65 demersal fish species in the North Sea, a marine ecosystem strongly altered by human activities and climate change. Our case study demonstrates how tensor decomposition can successfully (i) characterize the main spatio-temporal patterns and trends in species abundances, (ii) identify sub-communities of species that share similar spatial distribution and temporal dynamics, and (iii) reveal external drivers of change. Our results revealed a strong spatial structure in fish assemblages persistent over time and linked to differences in depth, primary production and seasonality. Furthermore, we simultaneously characterized important temporal distribution changes related to the low frequency temperature variability inherent in the Atlantic Multidecadal Oscillation. Finally, we identified six major sub-communities composed of species sharing similar spatial distribution patterns and temporal dynamics. Our case study demonstrates the application and benefits of using tensor decomposition for studying complex community data sets usually derived from large-scale monitoring programs. PMID:29136658

Land Area Change in Coastal Louisiana: A Multidecadal Perspective (from 1956 to 2006)

USGS Publications Warehouse

Barras, John A.; Bernier, Julie C.; Morton, Robert A.

2008-01-01

The U.S. Geological Survey (USGS) analyzed changes in the configuration of land and water in coastal Louisiana by using a sequential series of 14 data sets summarizing land and water areas from 1956 to 2006. The purpose of this study is to provide a spatially and temporally consistent source of quantitative information on land area across coastal Louisiana, broken into three physiographic provinces (the term 'coastal Louisiana' is used to present data on the collective area). The land-water data sets used in this study are interpreted through spatial analysis and by linear regression analysis. The spatial depictions of land area change reveal a complex and interwoven mosaic of loss and gain patterns caused by natural and human-induced processes operating at varied temporal and spatial scales, resulting in fluctuating contributions to coastal loss. The linear regression analysis provides a robust estimate of recent change trends by comparing land area over time for all data sets from 1985 to 2004 and from 1985 to 2006 by physiographic province across coastal Louisiana. The 1956 to 2006 map showing multidecadal changes, along with the linear regressions of land area change presented in this study, provide a comprehensive and concise presentation of historical trends and rates of land area change in coastal Louisiana. Taking a broad historical view provides an in-depth understanding of land area changes over time. For example, one observation provided by our historical review is that the majority of the widespread, nontransitory land gains depicted on the map over the past 50 years, with the exception of the progradation of the Atchafafalaya River and Wax Lake deltas, are primarily related to sediment placement and landward migration of barrier islands. Another point revealed by our historical approach is that recent land losses caused by hurricanes sometimes commingled with or exacerbated older losses formed during the 1956 to 1978 period. Furthermore, our analyses also show how the immediate impacts of extreme storms can alter the long-term, time-averaged trends of landscape change, thus limiting the range of projections for the future. For this reason, this study does not include trend projections beyond 2015 because of uncertainties related to recovery from the 2005 hurricane season and the potential for other episodic events that could skew future rates of change.

Temporal trend of in-hospital major bleeding among patients with non ST-elevation acute coronary syndromes.

PubMed

Elbarouni, Basem; Elmanfud, Omran; Yan, Raymond T; Fox, Keith A A; Kornder, Jan M; Rose, Barry; Spencer, Frederick A; Welsh, Robert C; Wong, Graham C; Goodman, Shaun G; Yan, Andrew T

2010-09-01

Although randomized controlled trials support the use of intensive medical and invasive therapies for non-ST segment elevation acute coronary syndromes (NSTE-ACS), major bleeding is a serious treatment complication. We sought to determine the temporal trend of in-hospital major bleeding among patients with NSTE-ACS, in relation to the evolving management pattern. We identified 14 111 NSTE-ACS patients enrolled in 4 successive, prospective, multicenter registries (ACS I, 1999-2001; ACS II, 2002-2003; GRACE, 2004-2007; and CANRACE, 2008) in Canada between 1999 and 2008. We collected data on patient characteristics, use of cardiac medications and procedures on standardized case report forms. In all registries, major bleeding was defined a priori as life threatening or fatal bleeding, bleeding requiring transfusion of ≥2 U of packed red cells, or resulting in an absolute decrease in hemoglobin of >30g/L. A total of 14 111 patients had a final diagnosis of NSTE-ACS and were included in this study (3294 in the ACS-I registry, 1956 in the ACS-II registry, 7543 in GRACE, and 1318 in CANRACE). Over time, there was a substantial increase in the use of dual anti-platelet (aspirin and thienopyridine) therapy (P for trend <.001), and in rates of in-hospital cardiac catheterization and percutaneous coronary intervention (both Ps for trend <.001). Overall, major bleeding was relatively infrequent (1.7%). There was no significant increase in the unadjusted rates of major bleeding over time (P for trend = .19). In multivariable analysis adjusting for GRACE risk score and intensive treatment, enrolment period was not an independent predictor of bleeding (P for trend = .98). There was no interaction between the enrolment period and the use of intensive medical and invasive management. Despite more widespread use of dual anti-platelet therapies and invasive cardiac procedures in the management of NSTE-ACS, the rate of major bleeding remains relatively low and has not increased significantly over time. Our findings suggest that physicians selectively target treatment for their patients, and these evidence-based therapies can be safely administered to ACS patients in clinical practice. 2010 Mosby, Inc. All rights reserved.

Temporal trends in health-related quality of life after stroke: analysis from the South London Stroke Register 1995-2011.

PubMed

Sheldenkar, Anita; Crichton, Siobhan; Douiri, Abdel; Rudd, Anthony G; Wolfe, Charles D A; Chen, Ruoling

2014-08-01

Survival after stroke has dramatically increased in the last two decades as the treatment of stroke has improved. However, time-trend analyses of health-related quality of life in stroke patients covering this time period are still not well investigated. The study aims to examine temporal trends in mental and physical health-related quality of life of stroke survivors between the period of 1995 and 2011. First in a lifetime strokes were registered in the South London Stroke Register between 1995 and 2011. Using the Short Form-12 Health Survey, trends in self-reported health-related quality of life at one-year after stroke were assessed over a 17-year period using linear regression, adjusting for socio-demographics, risk factors, and case-mix variables. Analyses stratifying by age, gender, race-ethnicity, and functional impairment were also performed. The overall trends of mental and physical health-related quality of life scores at one-year after stroke remained relatively unchanged over the period 1995-2011. However, mental health-related quality of life scores significantly improved between the period of 1995-2007 [β = 0·94 (95% CI; 0·15 to 1·74), P = 0·02], after which scores deteriorated [β = -2·02 (-3·82 to -0·22), P = 0·03]. Physical health-related quality of life scores remained stable until 2007, after which scores declined [β = -1·63 (-3·25 to -0·01), P = 0·05]. Despite declining health-related quality of life trends within the general population, stroke survivors' overall health-related quality of life remained unchanged, possibly due to lower expectations of health among stroke survivors. However, in recent years there has been a significant unexplained decline in both physical and mental health-related quality of life, suggesting that despite stroke policy aims to improve health-related quality of life, more needs to be done to target this decline. © 2014 The Authors. International Journal of Stroke © 2014 World Stroke Organization.

[Spatio-temporal problems of geographic information system in marine fishery].

PubMed

Su, Fenzhen; Zhou, Chenghu; Du, Yunyan; Zhang, Tianyu; Shao, Quanqin

2003-09-01

In marine fisheries, it is very important to understand and grasp the spatio-temporal nature. Geographical Information System (GIS) has been applied to describe or forecast the dynamic trend of resources or to set up evaluation model, which is one of high technologies in modern marine fisheries. Based on the review of the development of marine fishery GIS (MFGIS), four spatio-temporal problems it occurred were discussed, and the possible resolutions were prospected.

Historical trends in salinity and substrate in central Florida Bay: A paleoecological reconstruction using modern analogue data

USGS Publications Warehouse

Brewster-Wingard, G. L.; Ishman, S.E.

1999-01-01

Understanding the natural spatial and temporal variability that exists within an ecosystem is a critical component of efforts to restore systems to their natural state. Analysis of benthic foraminifers and molluscs from modern monitoring sites within Florida Bay allows us to determine what environmental parameters control spatial and temporal variability of their assemblages. Faunal assemblages associated with specific environmental parameters, including salinity and substrate, serve as proxies for an interpretation of paleoecologic data. The faunal record preserved in two shallow (< 2 m) cores in central Florida Bay (Russell Bank and Bob Allen Bank) provides a record of historical trends in environmental parameters for those sites. Analysis of these two cores has revealed two distinct patterns of salinity change at these sites: 1) a long-term trend of slightly increasing average salinity; and 2) a relatively rapid change to salinity fluctuations of greater frequency and amplitude, beginning around the turn of the century and becoming most pronounced after 1940. The degree of variability in substrate types at each locality limits interpretations of substrate trends to specific sites. A common sequence of change is present in the Russell Bank and Bob Allen Bank cores: from mixed grass and bare-sediment indicators at the bottom of the cores, to bare-sediment dwellers in the center, to a dominance of vegetative-cover indicators at the top of the cores. Changes in interpreted salinity patterns around the turn of the century are consistent with the timing of the construction of the Flagler Railroad from 1905 to 1912, and the Tamiami Trail and the canal and levee systems between 1915 and 1928. Beginning around 1940, the changes in the frequency and amplitude of salinity fluctuations may be related to changes in water management practices, meteorologic events (frequent hurricanes coupled with severe droughts in 1943 and 1944), or a combination of factors. The correspondence of these changes in Florida Bay with changes in the terrestrial Everglades suggests factors affecting the entire ecosystem are responsible for the salinity and substrate patterns seen in Florida Bay.

Analysis of water levels in the Frenchman Flat area, Nevada Test Site

USGS Publications Warehouse

Bright, D.J.; Watkins, S.A.; Lisle, B.A.

2001-01-01

Analysis of water levels in 21 wells in the Frenchman Flat area, Nevada Test Site, provides information on the accuracy of hydraulic-head calculations, temporal water-level trends, and potential causes of water-level fluctuations. Accurate hydraulic heads are particularly important in Frenchman Flat where the hydraulic gradients are relatively flat (less than 1 foot per mile) in the alluvial aquifer. Temporal water-level trends with magnitudes near or exceeding the regional hydraulic gradient may have a substantial effect on ground-water flow directions. Water-level measurements can be adjusted for the effects of barometric pressure, formation water density (from water-temperature measurements), borehole deviation, and land-surface altitude in selected wells in the Frenchman Flat area. Water levels in one well were adjusted for the effect of density; this adjustment was significantly greater (about 17 feet) than the adjustment of water levels for barometric pressure, borehole deviation, or land-surface altitude (less than about 4 feet). Water-level measurements from five wells exhibited trends that were statistically and hydrologically significant. Statistically significant water-level trends were observed for three wells completed in the alluvial aquifer (WW-5a, UE-5n, and PW-3), for one well completed in the carbonate aquifer (SM-23), and for one well completed in the quartzite confining unit (Army-6a). Potential causes of water-level fluctuations in wells in the Frenchman Flat area include changes in atmospheric conditions (precipitation and barometric pressure), Earth tides, seismic activity, past underground nuclear testing, and nearby pumping. Periodic water-level measurements in some wells completed in the carbonate aquifer indicate cyclic-type water-level fluctuations that generally correlate with longer term changes (more than 5 years) in precipitation. Ground-water pumping fromthe alluvial aquifer at well WW-5c and pumping and discharge from well RNM-2s appear to cause water-level fluctuations in nearby observation wells. The remaining known sources of water-level fluctuations do not appear to substantially affect water-level changes (seismic activity and underground nuclear testing) or do not affect changes over a period of more than 1 year (barometric pressure and Earth tides) in wells in the Frenchman Flat area.

Coastal ocean acidification and increasing total alkalinity in the northwestern Mediterranean Sea

NASA Astrophysics Data System (ADS)

Kapsenberg, Lydia; Alliouane, Samir; Gazeau, Frédéric; Mousseau, Laure; Gattuso, Jean-Pierre

2017-05-01

Coastal time series of ocean carbonate chemistry are critical for understanding how global anthropogenic change manifests in near-shore ecosystems. Yet, they are few and have low temporal resolution. At the time series station Point B in the northwestern Mediterranean Sea, seawater was sampled weekly from 2007 through 2015, at 1 and 50 m, and analyzed for total dissolved inorganic carbon (CT) and total alkalinity (AT). Parameters of the carbonate system such as pH (pHT, total hydrogen ion scale) were calculated and a deconvolution analysis was performed to identify drivers of change. The rate of surface ocean acidification was -0.0028 ± 0.0003 units pHT yr-1. This rate is larger than previously identified open-ocean trends due to rapid warming that occurred over the study period (0.072 ± 0.022 °C yr-1). The total pHT change over the study period was of similar magnitude as the diel pHT variability at this site. The acidification trend can be attributed to atmospheric carbon dioxide (CO2) forcing (59 %, 2.08 ± 0.01 ppm CO2 yr-1) and warming (41 %). Similar trends were observed at 50 m but rates were generally slower. At 1 m depth, the increase in atmospheric CO2 accounted for approximately 40 % of the observed increase in CT (2.97 ± 0.20 µmol kg-1 yr-1). The remaining increase in CT may have been driven by the same unidentified process that caused an increase in AT (2.08 ± 0.19 µmol kg-1 yr-1). Based on the analysis of monthly trends, synchronous increases in CT and AT were fastest in the spring-summer transition. The driving process of the interannual increase in AT has a seasonal and shallow component, which may indicate riverine or groundwater influence. This study exemplifies the importance of understanding changes in coastal carbonate chemistry through the lens of biogeochemical cycling at the land-sea interface. This is the first coastal acidification time series providing multiyear data at high temporal resolution. The data confirm rapid warming in the Mediterranean Sea and demonstrate coastal acidification with a synchronous increase in total alkalinity.

United States Producing and Nonproducing Crude Oil and Natural Gas Reserves From 1985 Through 2004

EIA Publications

2006-01-01

This report discusses the regional and temporal trends in producing and nonproducing crude oil and natural gas reserves using the Energy Information Administration's (EIA) categorization of reserves. The report first focuses on EIA's collection and reporting of crude oil and natural gas reserves data, followed by a discussion of the natural gas reserve trends, and then the crude oil reserve trends.

Global trends in visibility: Implications for dust sources

USGS Publications Warehouse

Mahowald, N.M.; Ballantine, J.A.; Feddema, J.; Ramankutty, N.

2007-01-01

There is a large uncertainty in the relative roles of human land use, climate change and carbon dioxide fertilization in changing desert dust source strength over the past 100 years, and the overall sign of human impacts on dust is not known. We used visibility data from meteorological stations in dusty regions to assess the anthropogenic impact on long term trends in desert dust emissions. We did this by looking at time series of visibility derived variables and their correlations with precipitation, drought, winds, land use and grazing. Visibility data are available at thousands of stations globally from 1900 to the present, but we focused on 357 stations with more than 30 years of data in regions where mineral aerosols play a dominant role in visibility observations. We evaluated the 1974 to 2003 time period because most of these stations have reliable records only during this time. We first evaluated the visibility data against AERONET aerosol optical depth data, and found that only in dusty regions are the two moderately correlated. Correlation coefficients between visibility-derived variables and AERONET optical depths indicate a moderate correlation (0.47), consistent with capturing about 20% of the variability in optical depths. Two visibility-derived variables appear to compare the best with AERONET observations: the fraction of observations with visibility less than 5 km (VIS5) and the surface extinction (EXT). Regional trends show that in many dusty places, VIS5 and EXT are statistically significantly correlated with the Palmer drought severity index (based on precipitation and temperature) or surface wind speeds, consistent with dust temporal variability being largely driven by meteorology. This is especially true for North African and Chinese dust sources, but less true in the Middle East, Australia or South America, where there are not consistent patterns in the correlations. Climate indices such as El Nino or the North Atlantic Oscillation are not correlated with visibility-derived variables in this analysis. There are few stations where visibility measures are correlated with cultivation or grazing estimates on a temporal basis, although this may be a function of the very coarse temporal resolution of the land use datasets. On the other hand, spatial analysis of the visibility data suggests that natural topographic lows are not correlated with VIS5 or EXT, but land use is correlated at a moderate level. This analysis is consistent with land use being important in some regions, but meteorology driving interannual variability during 1974-2003.

Spatio-temporal variability of droughts and terrestrial water storage over Lake Chad Basin using independent component analysis

NASA Astrophysics Data System (ADS)

Ndehedehe, Christopher E.; Agutu, Nathan O.; Okwuashi, Onuwa; Ferreira, Vagner G.

2016-09-01

Lake Chad has recently been perceived to be completely desiccated and almost extinct due to insufficient published ground observations. Given the high spatial variability of rainfall in the region, and the fact that extreme climatic conditions (for example, droughts) could be intensifying in the Lake Chad basin (LCB) due to human activities, a spatio-temporal approach to drought analysis becomes essential. This study employed independent component analysis (ICA), a fourth-order cumulant statistics, to decompose standardised precipitation index (SPI), standardised soil moisture index (SSI), and terrestrial water storage (TWS) derived from Gravity Recovery and Climate Experiment (GRACE) into spatial and temporal patterns over the LCB. In addition, this study uses satellite altimetry data to estimate variations in the Lake Chad water levels, and further employs relevant climate teleconnection indices (El-Niño Southern Oscillation-ENSO, Atlantic Multi-decadal Oscillation-AMO, and Atlantic Meridional Mode-AMM) to examine their links to the observed drought temporal patterns over the basin. From the spatio-temporal drought analysis, temporal evolutions of SPI at 12 month aggregation show relatively wet conditions in the last two decades (although with marked alterations) with the 2012-2014 period being the wettest. In addition to the improved rainfall conditions during this period, there was a statistically significant increase of 0.04 m/yr in altimetry water levels observed over Lake Chad between 2008 and 2014, which confirms a shift in the hydrological conditions of the basin. Observed trend in TWS changes during the 2002-2014 period shows a statistically insignificant increase of 3.0 mm/yr at the centre of the basin, coinciding with soil moisture deficit indicated by the temporal evolutions of SSI at all monthly accumulations during the 2002-2003 and 2009-2012 periods. Further, SPI at 3 and 6 month scales indicated fluctuating drought conditions at the extreme south of the basin, coinciding with a statistically insignificant decline in TWS of about 4.5 mm/yr at the southern catchment of the basin. Finally, correlation analyses indicate that ENSO, AMO, and AMM are associated with extreme rainfall conditions in the basin, with AMO showing the strongest association (statistically significant correlation of 0.55) with SPI 12 month aggregation. Therefore, this study provides a framework that will support drought monitoring in the LCB.

Spatio-temporal trends in monthly pan evaporation in Aguascalientes, Mexico

NASA Astrophysics Data System (ADS)

Ruiz-Alvarez, Osias; Singh, Vijay P.; Medina, Juan Enciso; Munster, Clyde; Kaiser, Ronald; Ontiveros-Capurata, Ronald Ernesto; Diaz-Garcia, Luis Antonio; dos Santos, Carlos Antonio Costa

2018-05-01

Emission of greenhouse gases is being alleged to be causing climate change in different regions of the world. The objective of this study was to analyze the spatio-temporal trends of monthly evaporation at 52 weather stations in the state of Aguascalientes (Mexico) which have hydrometeorological records of long periods. The autocorrelation was eliminated with an auto-regressive model, and the trend was determined using the Spearman (S) and Kendall (K) tests. The statistical significance of the trend was determined with the Spearman correlation coefficient (r s) and the Z statistic (the test statistic of the normal distribution) both indicated that that there were statistically significant trends in 107 time series, of these 88 series had negative trends and 19 series had positive trends. Negative trends were present in all months of the year, while positive trends occurred from February to May and from October to December only. The reduction of evaporation from - 4.10 to - 20.50 mm/month/year from June to September showed a hopeful future scenario for rainfed agriculture. Irrigated agriculture during dry months could have a reduction of irrigation requirements as a consequence of the reduction in reference and crop evapotranspiration. The evaporation increase during dry months could increase irrigation requirements and pumping, mainly in March, April, and November when there are trends with increases of about 26.90, 24.60, and 23.90 mm/month/year, respectively. The spatial variability of evaporation trend means that other effects of climate change could vary in different parts of the state. Results of this study will be useful for farmers and institutions in charge of the administration of water resources for developing adaptation and mitigation strategies to climate change.

Gene Tree Discordance Does Not Explain Away the Temporal Decline of Convergence in Mammalian Protein Sequence Evolution.

PubMed

Zou, Zhengting; Zhang, Jianzhi

2017-07-01

Several authors reported lower frequencies of protein sequence convergence between more distantly related evolutionary lineages and attributed this trend to epistasis, which renders the acceptable amino acids at a site more different and convergence less likely in more divergent lineages. A recent primate study, however, suggested that this trend is at least partially and potentially entirely an artifact of gene tree discordance (GTD). Here, we demonstrate in a genome-wide data set from 17 mammals that the temporal trend remains (1) upon the control of the GTD level, (2) in genes whose genealogies are concordant with the species tree, and (3) for convergent changes, which are extremely unlikely to be caused by GTD. Similar results are observed in a comparable data set of 12 fruit flies in some but not all of these tests. We conclude that, at least in some cases, the temporal decline of convergence is genuine, reflecting an impact of epistasis on protein evolution. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Long-term ground deformation patterns of Bucharest using multi-temporal InSAR and multivariate dynamic analyses: a possible transpressional system?

PubMed Central

Armaş, Iuliana; Mendes, Diana A.; Popa, Răzvan-Gabriel; Gheorghe, Mihaela; Popovici, Diana

2017-01-01

The aim of this exploratory research is to capture spatial evolution patterns in the Bucharest metropolitan area using sets of single polarised synthetic aperture radar (SAR) satellite data and multi-temporal radar interferometry. Three sets of SAR data acquired during the years 1992–2010 from ERS-1/-2 and ENVISAT, and 2011–2014 from TerraSAR-X satellites were used in conjunction with the Small Baseline Subset (SBAS) and persistent scatterers (PS) high-resolution multi-temporal interferometry (InSAR) techniques to provide maps of line-of-sight displacements. The satellite-based remote sensing results were combined with results derived from classical methodologies (i.e., diachronic cartography) and field research to study possible trends in developments over former clay pits, landfill excavation sites, and industrial parks. The ground displacement trend patterns were analysed using several linear and nonlinear models, and techniques. Trends based on the estimated ground displacement are characterised by long-term memory, indicated by low noise Hurst exponents, which in the long-term form interesting attractors. We hypothesize these attractors to be tectonic stress fields generated by transpressional movements. PMID:28252103

Long-term ground deformation patterns of Bucharest using multi-temporal InSAR and multivariate dynamic analyses: a possible transpressional system?

PubMed

Armaş, Iuliana; Mendes, Diana A; Popa, Răzvan-Gabriel; Gheorghe, Mihaela; Popovici, Diana

2017-03-02

The aim of this exploratory research is to capture spatial evolution patterns in the Bucharest metropolitan area using sets of single polarised synthetic aperture radar (SAR) satellite data and multi-temporal radar interferometry. Three sets of SAR data acquired during the years 1992-2010 from ERS-1/-2 and ENVISAT, and 2011-2014 from TerraSAR-X satellites were used in conjunction with the Small Baseline Subset (SBAS) and persistent scatterers (PS) high-resolution multi-temporal interferometry (InSAR) techniques to provide maps of line-of-sight displacements. The satellite-based remote sensing results were combined with results derived from classical methodologies (i.e., diachronic cartography) and field research to study possible trends in developments over former clay pits, landfill excavation sites, and industrial parks. The ground displacement trend patterns were analysed using several linear and nonlinear models, and techniques. Trends based on the estimated ground displacement are characterised by long-term memory, indicated by low noise Hurst exponents, which in the long-term form interesting attractors. We hypothesize these attractors to be tectonic stress fields generated by transpressional movements.

The effect of length and starting year on trend analyses of temperatures in Spanish mainland (1951-2010). Seasonal analyses: Autumn (V)

NASA Astrophysics Data System (ADS)

Salinas Solé, Celia; Peña Angulo, Dhais; Gonzalez HIgaldo, Jose Carlos; Brunetti, MIchele

2017-04-01

In this poster we applied the moving window approach (see Poster I of this collection) to analyze trends of autumn and its corresponding months (September, October, November) temperature mean values of maximum (Tmax) and minimum (Tmin) in Spanish mainland to detect the effects of length period and starting year. Monthly series belong to Monthly Temperature dataset of Spanish mainland (MOTEDAS). Database contains in its grid format of 5236 pixels of monthly series (10x10 km). The threshold used in spatial analyses considers 20% of land under significant trend (p<0.05). The most striking results are as follow: • Seasonal trend analyses of Autumn Tmax show no significance at any temporal Windows. Trends of Tmin are significant in more than 20% of land until 1974-2010. The area affected in Tmin progressively increase from SE to NW. • Monthly trend analyses not detect any significance in Tmax, while in Tmin, particularly in October, an extended area is detected in temporal windows in between 1951-2010 to 1978-2010, but clearly concentrated in the starting years of initial 70´s. Spatial pattern of areas affected significantly seems to be from SE to NW for October, and South-North in September. To conclude autumn trend analyses of Tmax and Tmin in Spanish mainland only detect significant trend in Tmin, mostly located in the 70´s and extending from SE to central areas of study area.

Pneumonia Mortality in Children Aged <5 Years in 56 Countries: A Retrospective Analysis of Trends from 1960 to 2012.

PubMed

Wu, Jie; Yang, Shigui; Cao, Qing; Ding, Cheng; Cui, Yuanxia; Zhou, Yuqing; Li, Yiping; Deng, Min; Wang, Chencheng; Xu, Kaijin; Ruan, Bing; Li, Lanjuan

2017-10-30

Pneumonia is now the second leading cause of death for children aged <5 years worldwide. However, analyses of the long-term evolution of under-5 mortality from pneumonia are still scarce in the literature. We aimed to explore long-term trends of under-5 mortality from pneumonia in 56 countries from 1960 to 2012. Data on under-5 mortality from pneumonia were extracted from the World Health Organization mortality database. Long-term trends were assessed for 56 countries and for 4 national income transition groups. We also used joinpoint regression analysis to detect distinct period segments of long-term trends and estimate the annual percent of changes of each period segment. The average mortality rate from pneumonia for children aged 0-4 years in 56 countries declined from 163.0 per 100000 children (95% confidence interval [CI], 119.4 to 212.8) in 1960 to 9.9 per 100000 children (95% CI, 6.4 to 13.4) in 2012, with an average annual percent of change of -5.6% (95% CI, -7.2% to -3.9%). The temporal trends of childhood mortality were different between national income transition groups. Our findings suggest a striking overall downward trend in under-5 mortality from pneumonia between 1960 and 2012. However, the rate and absolute terms of decline differ by national income transition group. These variable patterns between national income transition groups may inform further intervention setting and priority setting. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Epidemiological features and risk factors associated with the spatial and temporal distribution of human brucellosis in China

PubMed Central

2013-01-01

Background Human brucellosis incidence in China has been increasing dramatically since 1999. However, epidemiological features and potential factors underlying the re-emergence of the disease remain less understood. Methods Data on human and animal brucellosis cases at the county scale were collected for the year 2004 to 2010. Also collected were environmental and socioeconomic variables. Epidemiological features including spatial and temporal patterns of the disease were characterized, and the potential factors related to the spatial heterogeneity and the temporal trend of were analysed using Poisson regression analysis, Granger causality analysis, and autoregressive distributed lag (ADL) models, respectively. Results The epidemic showed a significantly higher spatial correlation with the number of sheep and goats than swine and cattle. The disease was most prevalent in grassland areas with elevation between 800–1,600 meters. The ADL models revealed that local epidemics were correlated with comparatively lower temperatures and less sunshine in winter and spring, with a 1–7 month lag before the epidemic peak in May. Conclusions Our findings indicate that human brucellosis tended to occur most commonly in grasslands at moderate elevation where sheep and goats were the predominant livestock, and in years with cooler winter and spring or less sunshine. PMID:24238301

Long-Term Monitoring of Dolphin Biosonar Activity in Deep Pelagic Waters of the Mediterranean Sea.

PubMed

Caruso, Francesco; Alonge, Giuseppe; Bellia, Giorgio; De Domenico, Emilio; Grammauta, Rosario; Larosa, Giuseppina; Mazzola, Salvatore; Riccobene, Giorgio; Pavan, Gianni; Papale, Elena; Pellegrino, Carmelo; Pulvirenti, Sara; Sciacca, Virginia; Simeone, Francesco; Speziale, Fabrizio; Viola, Salvatore; Buscaino, Giuseppa

2017-06-28

Dolphins emit short ultrasonic pulses (clicks) to acquire information about the surrounding environment, prey and habitat features. We investigated Delphinidae activity over multiple temporal scales through the detection of their echolocation clicks, using long-term Passive Acoustic Monitoring (PAM). The Istituto Nazionale di Fisica Nucleare operates multidisciplinary seafloor observatories in a deep area of the Central Mediterranean Sea. The Ocean noise Detection Experiment collected data offshore the Gulf of Catania from January 2005 to November 2006, allowing the study of temporal patterns of dolphin activity in this deep pelagic zone for the first time. Nearly 5,500 five-minute recordings acquired over two years were examined using spectrogram analysis and through development and testing of an automatic detection algorithm. Echolocation activity of dolphins was mostly confined to nighttime and crepuscular hours, in contrast with communicative signals (whistles). Seasonal variation, with a peak number of clicks in August, was also evident, but no effect of lunar cycle was observed. Temporal trends in echolocation corresponded to environmental and trophic variability known in the deep pelagic waters of the Ionian Sea. Long-term PAM and the continued development of automatic analysis techniques are essential to advancing the study of pelagic marine mammal distribution and behaviour patterns.

The effect of length and starting year on trend analyses of temperatures in Spanish mainland (1951-2010). Seasonal analysis: Winter (II)

NASA Astrophysics Data System (ADS)

Salinas Solé, Celia; Peña Angulo, Dhais; Gonzalez Hidalgo, Jose Carlos; Brunetti, Michele

2017-04-01

In this poster we applied the moving window approach (see Poster I of this collection) to analyze trends of winter and its corresponding months (December, January, February) temperature mean values of maximum (Tmax) and minimum (Tmin) in Spanish mainland to detect the effects of length period and starting year. Monthly series belong to Monthly Temperature dataset of Spanish mainland (MOTEDAS). Database contains in its grid format of 5236 pixels of monthly series (10x10 km). The threshold used in spatial analyses considers 20% of land under significant trend (p<0.05). The most striking results are as follow: • Seasonal trend analyses of Tmax shows that global trend 1951-2010 was positive and significant mostly in central-western areas; from 1970 to 2010 there is less than 20% of land with significant trend. In the case of Tmin no relevant significant period is detected. • Monthly Tmax analyses show that December significant trend changed from positive (>20%) in between 1955-2010 until 1962-2010, to negative from 1976-2010. Meanwhile January does not show relevant period with significant trend; finally Tmax in February shows different periods with positive significant trend (>20% of land) 1951-2010 to 1954-2010 and 1962-2010 to 1968-2010. No significant trend is detected after this data. • Monthly Tmin trend analyses show that except exceptional period, no months present any significant trend. As conclusions, we have detected that for winter and winter-months, Tmax trends are not significant from 1970 across Spanish mainland. In the case of Tmin we conclude that no significant trend have been occurred in any temporal windows analyzed. Results differ from what traditionally has been assumed that the increase of the average annual temperature was due to the increase of trends in the winter season. And these analyses also show that seasonal trend values could hide monthly behavior. So extreme caution should be taken into account when seasonal values are offered.

Monitoring of Typical Steppe Desertification Based on Time Series of Net Primary Productivity Data

NASA Astrophysics Data System (ADS)

Wang, Hongyan; Li, Qiangzi; Gao, Zhihai

2014-11-01

Monitoring of grassland condition is a basic prerequisite for finding the degradation of a territory under climatic and human pressures leading to desertification. The temporal change in vegetation productivity is a key indicator of grassland degradation. In this paper, taking the Xilin Gol League as a case, the net primary production (NPP) dynamic trends during 2001-2010 were analyzed, with the Mann-Kendall test. In this paper, in the study area where precipitation and NPP has significantly positive correlation, the residual trend method (RESTREND) was used to remove the annual NPP fluctuation caused by rainfall fluctuation and reduce the effect of precipitation on vegetation monitoring indicators. The results showed that An overall strong liner correlation between NPP and precipitation was observed in the Xilin Gol grassland, with 68.52% of the pixels analyzed being significantly correlated (α =0.1). The statistical analysis reveals that the NPP trend estimation generally shows a decreasing trend, with 13.02% of the Xilin Gol grassland being analyzed showing a significant trend (11.47% decrease and 1.55% increase). However, the Xilin Gol grassland desertification was not serious in the past ten years, only 5.16% of the study area where the vegetation productivity was significantly decreases (reducing the effect of precipitation).

Could Google Trends Be Used to Predict Methamphetamine-Related Crime? An Analysis of Search Volume Data in Switzerland, Germany, and Austria.

PubMed

Gamma, Alex; Schleifer, Roman; Weinmann, Wolfgang; Buadze, Anna; Liebrenz, Michael

2016-01-01

To compare the time trends of Google search interest in methamphetamine and criminal offences related to this drug. Google Trends data for the search term "meth" was compared to methamphetamine-related crime statistics (incl. use, possession, and dealing) in Switzerland, Germany, and Austria for the years 2004-2016. Google data was availably monthly. Crime data was available yearly, and monthly values were imputed. On the country level, internet search trends for "meth" roughly paralleled relevant criminal activity. State-level data, which was available for Austria, showed more heterogeneity. Cross-correlations for yearly data almost always peaked at a lag time of 0 and coefficients were mostly between 0.7 and 1.0 on the country level, and between 0.5 to 1.0 on the state level. Monthly cross-correlations based on imputed values were substantially lower, ranging from 0 to 0.6. These results encourage the further evaluation by law enforcement authorities of Google search activity as a possible predictor of methamphetamine-related crime. However, several limitations, in particular the crude temporal resolution of available crime data, precluded a detailed assessment of the relationship between internet search trends and the development of methamphetamine-related crime in central Europe.

Precipitation collector bias and its effects on temporal trends and spatial variability in National Atmospheric Deposition Program/National Trends Network data

USGS Publications Warehouse

Wetherbee, Gregory A.

2017-01-01

Precipitation samples have been collected by the National Atmospheric Deposition Program's (NADP) National Trends Network (NTN) using the Aerochem Metrics Model 301 (ACM) collector since 1978. Approximately one-third of the NTN ACM collectors have been replaced with N-CON Systems, Inc. Model ADS 00-120 (NCON) collectors. Concurrent data were collected over 6 years at 12 NTN sites using colocated ACM and NCON collectors in various precipitation regimes. Linear regression models of the colocated data were used to adjust for relative bias between the collectors. Replacement of ACM collectors with NCON collectors resulted in shifts in 10-year seasonal precipitation-weighted mean concentration (PWMC) trend slopes for: cations (−0.001 to −0.007 mgL−1yr−1), anions (−0.009 to −0.028 mgL−1yr−1), and hydrogen ion (+0.689 meqL-1yr−1). Larger shifts in NO3− and SO4−2 seasonal PWMC trend slopes were observed in the Midwest and Northeast US, where concentrations are generally higher than in other regions. Geospatial analysis of interpolated concentration rasters indicated regions of accentuated variability introduced by incorporation of NCON collectors into the NTN.

Satellite-based trends of solar radiation and cloud parameters in Europe

NASA Astrophysics Data System (ADS)

Pfeifroth, Uwe; Bojanowski, Jedrzej S.; Clerbaux, Nicolas; Manara, Veronica; Sanchez-Lorenzo, Arturo; Trentmann, Jörg; Walawender, Jakub P.; Hollmann, Rainer

2018-04-01

Solar radiation is the main driver of the Earth's climate. Measuring solar radiation and analysing its interaction with clouds are essential for the understanding of the climate system. The EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) generates satellite-based, high-quality climate data records, with a focus on the energy balance and water cycle. Here, multiple of these data records are analyzed in a common framework to assess the consistency in trends and spatio-temporal variability of surface solar radiation, top-of-atmosphere reflected solar radiation and cloud fraction. This multi-parameter analysis focuses on Europe and covers the time period from 1992 to 2015. A high correlation between these three variables has been found over Europe. An overall consistency of the climate data records reveals an increase of surface solar radiation and a decrease in top-of-atmosphere reflected radiation. In addition, those trends are confirmed by negative trends in cloud cover. This consistency documents the high quality and stability of the CM SAF climate data records, which are mostly derived independently from each other. The results of this study indicate that one of the main reasons for the positive trend in surface solar radiation since the 1990's is a decrease in cloud coverage even if an aerosol contribution cannot be completely ruled out.

Spatio-temporal monitoring of vegetation phenology in the dry sub-humid region of Nigeria using time series of AVHRR NDVI and TAMSAT datasets

NASA Astrophysics Data System (ADS)

Osunmadewa, Babatunde Adeniyi; Gebrehiwot, Worku Zewdie; Csaplovics, Elmar; Adeofun, Olabinjo Clement

2018-03-01

Time series data are of great importance for monitoring vegetation phenology in the dry sub-humid regions where change in land cover has influence on biomass productivity. However few studies have inquired into examining the impact of rainfall and land cover change on vegetation phenology. This study explores Seasonal Trend Analysis (STA) approach in order to investigate overall greenness, peak of annual greenness and timing of annual greenness in the seasonal NDVI cycle. Phenological pattern for the start of season (SOS) and end of season (EOS) was also examined across different land cover types in four selected locations. A significant increase in overall greenness (amplitude 0) and a significant decrease in other greenness trend maps (amplitude 1 and phase 1) was observed over the study period. Moreover significant positive trends in overall annual rainfall (amplitude 0) was found which follows similar pattern with vegetation trend. Variation in the timing of peak of greenness (phase 1) was seen in the four selected locations, this indicate a change in phenological trend. Additionally, strong relationship was revealed by the result of the pixel-wise regression between NDVI and rainfall. Change in vegetation phenology in the study area is attributed to climatic variability than anthropogenic activities.

Bayesian spatiotemporal crash frequency models with mixture components for space-time interactions.

PubMed

Cheng, Wen; Gill, Gurdiljot Singh; Zhang, Yongping; Cao, Zhong

2018-03-01

The traffic safety research has developed spatiotemporal models to explore the variations in the spatial pattern of crash risk over time. Many studies observed notable benefits associated with the inclusion of spatial and temporal correlation and their interactions. However, the safety literature lacks sufficient research for the comparison of different temporal treatments and their interaction with spatial component. This study developed four spatiotemporal models with varying complexity due to the different temporal treatments such as (I) linear time trend; (II) quadratic time trend; (III) Autoregressive-1 (AR-1); and (IV) time adjacency. Moreover, the study introduced a flexible two-component mixture for the space-time interaction which allows greater flexibility compared to the traditional linear space-time interaction. The mixture component allows the accommodation of global space-time interaction as well as the departures from the overall spatial and temporal risk patterns. This study performed a comprehensive assessment of mixture models based on the diverse criteria pertaining to goodness-of-fit, cross-validation and evaluation based on in-sample data for predictive accuracy of crash estimates. The assessment of model performance in terms of goodness-of-fit clearly established the superiority of the time-adjacency specification which was evidently more complex due to the addition of information borrowed from neighboring years, but this addition of parameters allowed significant advantage at posterior deviance which subsequently benefited overall fit to crash data. The Base models were also developed to study the comparison between the proposed mixture and traditional space-time components for each temporal model. The mixture models consistently outperformed the corresponding Base models due to the advantages of much lower deviance. For cross-validation comparison of predictive accuracy, linear time trend model was adjudged the best as it recorded the highest value of log pseudo marginal likelihood (LPML). Four other evaluation criteria were considered for typical validation using the same data for model development. Under each criterion, observed crash counts were compared with three types of data containing Bayesian estimated, normal predicted, and model replicated ones. The linear model again performed the best in most scenarios except one case of using model replicated data and two cases involving prediction without including random effects. These phenomena indicated the mediocre performance of linear trend when random effects were excluded for evaluation. This might be due to the flexible mixture space-time interaction which can efficiently absorb the residual variability escaping from the predictable part of the model. The comparison of Base and mixture models in terms of prediction accuracy further bolstered the superiority of the mixture models as the mixture ones generated more precise estimated crash counts across all four models, suggesting that the advantages associated with mixture component at model fit were transferable to prediction accuracy. Finally, the residual analysis demonstrated the consistently superior performance of random effect models which validates the importance of incorporating the correlation structures to account for unobserved heterogeneity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Epidemiology of bronchiolitis: a description of emergency department visits and hospitalizations in Puerto Rico, 2010-2014.

PubMed

Rivera-Sepulveda, Andrea; Garcia-Rivera, Enid J

2017-01-01

Little is known about the epidemiology of bronchiolitis as a clinical diagnosis and its impact on emergency department visits and hospitalizations in tropical and semitropical regions. We described the epidemiology of bronchiolitis emergency visits and hospitalizations, its temporal trend and geographic distribution in Puerto Rico between 2010 and 2014. We performed a retrospective descriptive analysis of a representative sample of privately insured children with bronchiolitis from January 2010 to December 2014. Data was provided by the largest private health insurer in Puerto Rico and identified children < 24 months of age with bronchiolitis by International Classification of Diseases, Ninth Revision code 466, 466.11, and 466.19. Chi-square and one-way ANOVA compared sex, age, diagnosis, and severity across the years. Joinpoint Poisson regression analysis evaluated the temporal trend distribution of bronchiolitis hospitalizations per calendar year. A P value less than 0.05 was statistically significant. During the study period, the annual proportion of emergency department visits and hospitalizations due to bronchiolitis increased from 3 to 5%, and 26 to 38%, respectively. The annual incidence rate of hospitalizations was 3.2 per 1000 privately insured children < 24 months. Non-RSV bronchiolitis was the most frequent diagnosis (51%). Hospitalizations occurred year-round, but increased significantly from August through December. Most children hospitalized resided in the metropolitan San Juan (35%) and surrounding urban areas. Total hospital charges decreased from $3.78 to $3.74 million, with an average cost per hospitalization of $4320.12 (11.3% increase; P  = 0.0015). This is the first study that evaluates the epidemiological characteristics of bronchiolitis in a primarily Hispanic population, living in a tropical country, and using data from a privately insured population. We found a small but significant increase in proportion of emergency visits and hospitalizations. Temporal trend shows year-round hospitalizations with an earlier seasonal peak and longer duration, consistent with Puerto Rico's seasonal rainfall throughout the study period. Further studies are needed to elucidate whether this epidemiologic pattern can also be seen in publicly insured children and whether Hispanic ethnicity is a risk factor for increased hospitalizations or is related to health disparities in the US healthcare system.

Temporal Trends in Phthalate Exposures: Findings from the National Health and Nutrition Examination Survey, 2001–2010

PubMed Central

Calafat, Antonia M.; Woodruff, Tracey J.

2014-01-01

Background: Phthalates are ubiquitous environmental contaminants. Because of potential adverse effects on human health, butylbenzyl phthalate [BBzP; metabolite, monobenzyl phthalate (MBzP)], di-n-butyl phthalate [DnBP; metabolite, mono-n-butyl phthalate (MnBP)], and di(2-ethylhexyl) phthalate (DEHP) are being replaced by substitutes including other phthalates; however, little is known about consequent trends in population-level exposures. Objective: We examined temporal trends in urinary concentrations of phthalate metabolites in the general U.S. population and whether trends vary by sociodemographic characteristics. Methods: We combined data on 11 phthalate metabolites for 11,071 participants from five cycles of the National Health and Nutrition Examination Survey (2001–2010). Percent changes and least square geometric means (LSGMs) were calculated from multivariate regression models. Results: LSGM concentrations of monoethyl phthalate, MnBP, MBzP, and ΣDEHP metabolites decreased between 2001–2002 and 2009–2010 [percent change (95% CI): –42% (–49, –34); –17% (–23, –9); –32% (–39, –23) and –37% (–46, –26), respectively]. In contrast, LSGM concentrations of monoisobutyl phthalate, mono(3-carboxypropyl) phthalate (MCPP), monocarboxyoctyl phthalate, and monocarboxynonyl phthalate (MCNP) increased over the study period [percent change (95% CI): 206% (178, 236); 25% (8, 45); 149% (102, 207); and 15% (1, 30), respectively]. Trends varied by subpopulations for certain phthalates. For example, LSGM concentrations of ΣDEHP metabolites, MCPP, and MCNP were higher in children than adults, but the gap between groups narrowed over time (pinteraction < 0.01). Conclusions: Exposure of the U.S. population to phthalates has changed in the last decade. Data gaps make it difficult to explain trends, but legislative activity and advocacy campaigns by nongovernmental organizations may play a role in changing trends. Citation: Zota AZ, Calafat AM, Woodruff TJ. 2014. Temporal trends in phthalate exposures: findings from the National Health and Nutrition Examination Survey, 2001–2010. Environ Health Perspect 122:235–241; http://dx.doi.org/10.1289/ehp.1306681 PMID:24425099

Temporal trends (1987-2002) of persistent, bioaccumulative and toxic (PBT) chemicals in beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary, Canada.

PubMed

Lebeuf, Michel; Noël, Michelle; Trottier, Steve; Measures, Lena

2007-09-20

Temporal trends of persistent, bioaccumulative and toxic (PBT) chemicals were examined in beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary (SLE), Canada. Blubber samples of 86 adult belugas were collected from animals stranded on the shore of the SLE between 1987 and 2002 and analyzed for several regulated PBTs, including polychlorinated biphenyls (PCBs), p,p'dichlorodiphenyltrichloroethane (DDT) and its metabolites, chlordane (CHL) and related compounds, hexachlorocyclohexane (HCH) isomers, hexachlorobenzene (HCB) and Mirex. In addition, time trends of tris(4-chlorophenyl)methane (TCPMe) and tris(4-chlorophenyl)methanol (TCPMOH), two compounds that may origin from DDT formulations, were also examined. Concentrations of most of the PBTs examined had exponentially decreased by at least a factor of two (half-life time (t(1/2))<15 years) in beluga between 1987 and 2002 while no increasing trends were observed for any of the PBTs measured. The decreasing trends of PBT concentrations in SLE beluga may be due to a decline in contamination of its diet following North American and international regulations on the use and production of these compounds or by a change in its diet itself or by a combination of both. Some PBTs did not exhibit any significant trends in beluga possibly because the most intense elimination phase subsequent to legislative regulations occurred prior to the 1987-2002 time period. Other chemicals, such gamma-HCH, did not significantly decrease likely because they are still currently used in some restricted applications. Conversely, alpha-HCH showed a significant decreasing trend indicating that SigmaHCHs is not representative of all HCHs. Both TCPMe and TCPMOH exhibited no trends in beluga during the time period examined. The metabolic capacity of SLE beluga has apparently accelerated the depletion of at least one PBT, namely CB-28/31. A significant relationship between the half-life of PBTs in beluga and log Kow was observed for most of the chemicals examined. Several factors are expected to have influenced the temporal changes of PBT concentrations in beluga which limit the usefulness of this species as a bioindicator of changes in PBT contamination in the SLE ecosystem.

Spatial and Temporal Trends in Stable Carbon and Oxygen Isotope Ratios of Juvenile Winter Flounder

EPA Science Inventory

Isotopic ratios of fish otoliths have been used in numerous studies as natural tags or markers to aid the study of connectivity among fish populations. We investigated the use of spatial and temporal changes in the stable carbon and oxygen isotope ratios of otoliths to different...

The steady-state mosaic of disturbance and succession across an old-growth Central Amazon forest landscape.

PubMed

Chambers, Jeffrey Q; Negron-Juarez, Robinson I; Marra, Daniel Magnabosco; Di Vittorio, Alan; Tews, Joerg; Roberts, Dar; Ribeiro, Gabriel H P M; Trumbore, Susan E; Higuchi, Niro

2013-03-05

Old-growth forest ecosystems comprise a mosaic of patches in different successional stages, with the fraction of the landscape in any particular state relatively constant over large temporal and spatial scales. The size distribution and return frequency of disturbance events, and subsequent recovery processes, determine to a large extent the spatial scale over which this old-growth steady state develops. Here, we characterize this mosaic for a Central Amazon forest by integrating field plot data, remote sensing disturbance probability distribution functions, and individual-based simulation modeling. Results demonstrate that a steady state of patches of varying successional age occurs over a relatively large spatial scale, with important implications for detecting temporal trends on plots that sample a small fraction of the landscape. Long highly significant stochastic runs averaging 1.0 Mg biomass⋅ha(-1)⋅y(-1) were often punctuated by episodic disturbance events, resulting in a sawtooth time series of hectare-scale tree biomass. To maximize the detection of temporal trends for this Central Amazon site (e.g., driven by CO2 fertilization), plots larger than 10 ha would provide the greatest sensitivity. A model-based analysis of fractional mortality across all gap sizes demonstrated that 9.1-16.9% of tree mortality was missing from plot-based approaches, underscoring the need to combine plot and remote-sensing methods for estimating net landscape carbon balance. Old-growth tropical forests can exhibit complex large-scale structure driven by disturbance and recovery cycles, with ecosystem and community attributes of hectare-scale plots exhibiting continuous dynamic departures from a steady-state condition.

Persistence of space radiation induced cytogenetic damage in the blood lymphocytes of astronauts.

PubMed

George, K; Chappell, L J; Cucinotta, F A

2010-08-14

Cytogenetic damage was assessed in blood lymphocytes from 16 astronauts before and after they participated in long-duration space missions of 3 months or more. The frequency of chromosome damage was measured by fluorescence in situ hybridization (FISH) chromosome painting before flight and at various intervals from a few days to many months after return from the mission. For all individuals, the frequency of chromosome exchanges measured within a month of return from space was higher than their preflight yield. However, some individuals showed a temporal decline in chromosome damage with time after flight. Statistical analysis using combined data for all astronauts indicated a significant overall decreasing trend in total chromosome exchanges with time after flight, although this trend was not seen for all astronauts and the yield of chromosome damage in some individuals actually increased with time after flight. The decreasing trend in total exchanges was slightly more significant when statistical analysis was restricted to data collected more than 220 days after return from flight. When analysis was restricted to data collected within 220 days of return from the mission there was no relationship between total exchanges and time. Translocation yields varied more between astronauts and there was only a slight non-significant decrease with time after flight that was similar for both later and earlier sampling times. Copyright (c) 2010. Published by Elsevier B.V.