The radiated electromagnetic field from collimated gamma rays and electron beams in air

NASA Astrophysics Data System (ADS)

Tumolillo, T. A.; Wondra, J. P.; Hobbs, W. E.; Smith, K.

1980-12-01

Nuclear weapons effects computer codes are used to study the electromagnetic field produced by gamma rays or by highly relativistic electron beams moving through the air. Consideration is given to large-area electron and gamma beams, small-area electron beams, variation of total beam current, variation of pressure in the beam channel, variation of the beam rise time, variation of beam radius, far-field radiated signals, and induced current on a system from a charged-particle beam. The work has application to system EMP coupling from nuclear weapons or charged-particle-beam weapons.

Modelling small-area inequality in premature mortality using years of life lost rates

NASA Astrophysics Data System (ADS)

Congdon, Peter

2013-04-01

Analysis of premature mortality variations via standardized expected years of life lost (SEYLL) measures raises questions about suitable modelling for mortality data, especially when developing SEYLL profiles for areas with small populations. Existing fixed effects estimation methods take no account of correlations in mortality levels over ages, causes, socio-ethnic groups or areas. They also do not specify an underlying data generating process, or a likelihood model that can include trends or correlations, and are likely to produce unstable estimates for small-areas. An alternative strategy involves a fully specified data generation process, and a random effects model which "borrows strength" to produce stable SEYLL estimates, allowing for correlations between ages, areas and socio-ethnic groups. The resulting modelling strategy is applied to gender-specific differences in SEYLL rates in small-areas in NE London, and to cause-specific mortality for leading causes of premature mortality in these areas.

Geographic Variations of Colorectal and Breast Cancer Late-Stage Diagnosis and the Effects of Neighborhood-Level Factors.

PubMed

Lin, Yan; Wimberly, Michael C

2017-04-01

The purpose of this study was to examine the geographic variations of late-stage diagnosis in colorectal cancer (CRC) and breast cancer as well as to investigate the effects of 3 neighborhood-level factors-socioeconomic deprivation, urban/rural residence, and spatial accessibility to health care-on the late-stage risks. This study used population-based South Dakota cancer registry data from 2001 to 2012. A total of 4,878 CRC cases and 6,418 breast cancer cases were included in the analyses. Two-level logistic regression models were used to analyze the risk of late-stage CRC and breast cancer. For CRC, there was a small geographic variation across census tracts in late-stage diagnosis, and residing in isolated small rural areas was significantly associated with late-stage risk. However, this association became nonsignificant after adjusting for census-tract level socioeconomic deprivation. Socioeconomic deprivation was an independent predictor of CRC late-stage risk, and it explained the elevated risk among American Indians. No relationship was found between spatial accessibility and CRC late-stage risk. For breast cancer, no geographic variation in the late-stage diagnosis was observed across census tracts, and none of the 3 neighborhood-level factors was significantly associated with late-stage risk. Results suggested that socioeconomic deprivation, rather than spatial accessibility, contributed to CRC late-stage risks in South Dakota as a rural state. CRC intervention programs could be developed to target isolated small rural areas, socioeconomically disadvantaged areas, as well as American Indians residing in these areas. © 2016 National Rural Health Association.

Slope instability caused by small variations in hydraulic conductivity

USGS Publications Warehouse

Reid, M.E.

1997-01-01

Variations in hydraulic conductivity can greatly modify hillslope ground-water flow fields, effective-stress fields, and slope stability. In materials with uniform texture, hydraulic conductivities can vary over one to two orders of magnitude, yet small variations can be difficult to determine. The destabilizing effects caused by small (one order of magnitude or less) hydraulic conductivity variations using ground-water flow modeling, finite-element deformation analysis, and limit-equilibrium analysis are examined here. Low hydraulic conductivity materials that impede downslope ground-water flow can create unstable areas with locally elevated pore-water pressures. The destabilizing effects of small hydraulic heterogeneities can be as great as those induced by typical variations in the frictional strength (approximately 4??-8??) of texturally similar materials. Common "worst-case" assumptions about ground-water flow, such as a completely saturated "hydrostatic" pore-pressure distribution, do not account for locally elevated pore-water pressures and may not provide a conservative slope stability analysis. In site characterization, special attention should be paid to any materials that might impede downslope ground-water flow and create unstable regions.

Estimating population prevalence of psychiatric conditions by small area with applications to analysing outcome and referral variations.

PubMed

Congdon, Peter

2006-12-01

This paper considers the development of estimates of mental illness prevalence for small areas and applications in explaining psychiatric outcomes and in assessing service provision. Estimates of prevalence are based on a logistic regression analysis of two national studies that provides model based estimates of relative morbidity risk by demographic, socio-economic and ethnic group for major psychiatric conditions; household/marital and area status also figure in the regression. Relative risk estimates are used, along with suitably disaggregated census populations, to make prevalence estimates for 354 English local authorities (LAs). Two applications are considered: the first involves analysis of variations in schizophrenia referrals and suicide mortality over English LAs that takes account of prevalence differences, and the second involves assessing hospital referral and bed use in relation to prevalence (for ages 16-74) for a case study area, Waltham Forest in NE London.

Characterization of surface and ground water δ18O seasonal variation and its use for estimating groundwater residence times

USGS Publications Warehouse

Reddy, Michael M.; Schuster, Paul; Kendall, Carol; Reddy, Micaela B.

2006-01-01

18O is an ideal tracer for characterizing hydrological processes because it can be reliably measured in several watershed hydrological compartments. Here, we present multiyear isotopic data, i.e. 18O variations (δ18O), for precipitation inputs, surface water and groundwater in the Shingobee River Headwaters Area (SRHA), a well-instrumented research catchment in north-central Minnesota. SRHA surface waters exhibit δ18O seasonal variations similar to those of groundwaters, and seasonal δ18O variations plotted versus time fit seasonal sine functions. These seasonal δ18O variations were interpreted to estimate surface water and groundwater mean residence times (MRTs) at sampling locations near topographically closed-basin lakes. MRT variations of about 1 to 16 years have been estimated over an area covering about 9 km2 from the basin boundary to the most downgradient well. Estimated MRT error (±0·3 to ±0·7 years) is small for short MRTs and is much larger (±10 years) for a well with an MRT (16 years) near the limit of the method. Groundwater transit time estimates based on Darcy's law, tritium content, and the seasonal δ18O amplitude approach appear to be consistent within the limits of each method. The results from this study suggest that use of the δ18O seasonal variation method to determine MRTs can help assess groundwater recharge areas in small headwaters catchments.

Characterization of surface and ground water δ18O seasonal variation and its use for estimating groundwater residence times

USGS Publications Warehouse

Reddy, Michael M.; Schuster, Paul F.; Kendall, Carol; Reddy, Micaela B.

2006-01-01

18O is an ideal tracer for characterizing hydrological processes because it can be reliably measured in several watershed hydrological compartments. Here, we present multiyear isotopic data, i.e. 18O variations (δ18O), for precipitation inputs, surface water and groundwater in the Shingobee River Headwaters Area (SRHA), a well-instrumented research catchment in north-central Minnesota. SRHA surface waters exhibit δ18O seasonal variations similar to those of groundwaters, and seasonal δ18O variations plotted versus time fit seasonal sine functions. These seasonal δ18O variations were interpreted to estimate surface water and groundwater mean residence times (MRTs) at sampling locations near topographically closed-basin lakes. MRT variations of about 1 to 16 years have been estimated over an area covering about 9 km2 from the basin boundary to the most downgradient well. Estimated MRT error (±0·3 to ±0·7 years) is small for short MRTs and is much larger (±10 years) for a well with an MRT (16 years) near the limit of the method. Groundwater transit time estimates based on Darcy's law, tritium content, and the seasonal δ18O amplitude approach appear to be consistent within the limits of each method. The results from this study suggest that use of the δ18O seasonal variation method to determine MRTs can help assess groundwater recharge areas in small headwaters catchments.

Income level and regional policies, underlying factors associated with unwarranted variations in conservative breast cancer surgery in Spain

PubMed Central

2011-01-01

Background Geographical variations in medical practice are expected to be small when the evidence about the effectiveness and safety of a particular technology is abundant. This would be the case of the prescription of conservative surgery in breast cancer patients. In these cases, when variation is larger than expected by need, socioeconomic factors have been argued as an explanation. Objectives: Using an ecologic design, our study aims at describing the variability in the use of surgical conservative versus non-conservative treatment. Additionally, it seeks to establish whether the socioeconomic status of the healthcare area influences the use of one or the other technique. Methods 81,868 mastectomies performed between 2002 and 2006 in 180 healthcare areas were studied. Standardized utilization rates of breast cancer conservative (CS) and non-conservative (NCS) procedures were estimated as well as the variation among areas, using small area statistics. Concentration curves and dominance tests were estimated to determine the impact of income and instruction levels in the healthcare area on surgery rates. Multilevel analyses were performed to determine the influence of regional policies. Results Variation in the use of CS was massive (4-fold factor between the highest and the lowest rate) and larger than in the case of NCS (2-fold), whichever the age group. Healthcare areas with higher economic and instruction levels showed highest rates of CS, regardless of the age group, while areas with lower economic and educational levels yielded higher rates of NCS interventions. Living in a particular Autonomous Community (AC), explained a substantial part of the CS residual variance (up to a 60.5% in women 50 to 70). Conclusion The place where a woman lives -income level and regional policies- explain the unexpectedly high variation found in utilization rates of conservative breast cancer surgery. PMID:21504577

Biomechanical effects, lithological variations, and local pedodiversity in some forest soils of Arkansas

Treesearch

Jonathan D. Phillips; Daniel A. Marion

2005-01-01

A high degree of soil variability over short distances and small areas is common, particularly in forest soils. This variability is sometimes, but not always, related to readily apparent variations in the environmental factors that control soil formation. This study examines the potential role of biomechanical effects of trees and of lithological variations within the...

Opportunities for Cost-Sharing in Conservation: Variation in Volunteering Effort across Protected Areas

PubMed Central

Armsworth, Paul R.; Cantú-Salazar, Lisette; Parnell, Mark; Booth, Josephine E.; Stoneman, Rob; Davies, Zoe G.

2013-01-01

Efforts to expand protected area networks are limited by the costs of managing protected sites. Volunteers who donate labor to help manage protected areas can help defray these costs. However, volunteers may be willing to donate more labor to some protected areas than others. Understanding variation in volunteering effort would enable conservation organizations to account for volunteer labor in their strategic planning. We examined variation in volunteering effort across 59 small protected areas managed by Yorkshire Wildlife Trust, a regional conservation nonprofit in the United Kingdom. Three surveys of volunteering effort reveal consistent patterns of variation across protected areas. Using the most detailed of these sources, a survey of site managers, we estimate that volunteers provided 3200 days of labor per year across the 59 sites with a total value exceeding that of paid staff time spent managing the sites. The median percentage by which volunteer labor supplements management costs on the sites was 36%. Volunteering effort and paid management costs are positively correlated, after controlling for the effect of site area. We examined how well a range of characteristics of the protected areas and surrounding communities explain variation in volunteering effort. Protected areas that are larger have been protected for longer and that are located near to denser conurbations experience greater volunteering effort. Together these factors explain 38% of the observed variation in volunteering effort across protected areas. PMID:23383176

Opportunities for cost-sharing in conservation: variation in volunteering effort across protected areas.

PubMed

Armsworth, Paul R; Cantú-Salazar, Lisette; Parnell, Mark; Booth, Josephine E; Stoneman, Rob; Davies, Zoe G

2013-01-01

Efforts to expand protected area networks are limited by the costs of managing protected sites. Volunteers who donate labor to help manage protected areas can help defray these costs. However, volunteers may be willing to donate more labor to some protected areas than others. Understanding variation in volunteering effort would enable conservation organizations to account for volunteer labor in their strategic planning. We examined variation in volunteering effort across 59 small protected areas managed by Yorkshire Wildlife Trust, a regional conservation nonprofit in the United Kingdom. Three surveys of volunteering effort reveal consistent patterns of variation across protected areas. Using the most detailed of these sources, a survey of site managers, we estimate that volunteers provided 3200 days of labor per year across the 59 sites with a total value exceeding that of paid staff time spent managing the sites. The median percentage by which volunteer labor supplements management costs on the sites was 36%. Volunteering effort and paid management costs are positively correlated, after controlling for the effect of site area. We examined how well a range of characteristics of the protected areas and surrounding communities explain variation in volunteering effort. Protected areas that are larger have been protected for longer and that are located near to denser conurbations experience greater volunteering effort. Together these factors explain 38% of the observed variation in volunteering effort across protected areas.

Small temperature coefficient of resistivity of graphene/graphene oxide hybrid membranes.

PubMed

Sun, Pengzhan; Zhu, Miao; Wang, Kunlin; Zhong, Minlin; Wei, Jinquan; Wu, Dehai; Zhu, Hongwei

2013-10-09

Materials with low temperature coefficient of resistivity (TCR) are of great importance in some areas, for example, highly accurate electronic measurement instruments and microelectronic integrated circuits. In this work, we demonstrated the ultrathin graphene-graphene oxide (GO) hybrid films prepared by layer-by-layer assembly with very small TCR (30-100 °C) in the air. Electrical response of the hybrid films to temperature variation was investigated along with the progressive reduction of GO sheets. The mechanism of electrical response to temperature variation of the hybrid film was discussed, which revealed that the interaction between graphene and GO and the chemical doping effect were responsible for the tunable control of its electrical response to temperature variation. The unique properties of graphene-GO hybrid film made it a promising candidate in many areas, such as high-end film electronic device and sensor applications.

Validation of spatiodemographic estimates produced through data fusion of small area census records and household microdata

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

Rose, Amy N.; Nagle, Nicholas N.

Techniques such as Iterative Proportional Fitting have been previously suggested as a means to generate new data with the demographic granularity of individual surveys and the spatial granularity of small area tabulations of censuses and surveys. This article explores internal and external validation approaches for synthetic, small area, household- and individual-level microdata using a case study for Bangladesh. Using data from the Bangladesh Census 2011 and the Demographic and Health Survey, we produce estimates of infant mortality rate and other household attributes for small areas using a variation of an iterative proportional fitting method called P-MEDM. We conduct an internalmore » validation to determine: whether the model accurately recreates the spatial variation of the input data, how each of the variables performed overall, and how the estimates compare to the published population totals. We conduct an external validation by comparing the estimates with indicators from the 2009 Multiple Indicator Cluster Survey (MICS) for Bangladesh to benchmark how well the estimates compared to a known dataset which was not used in the original model. The results indicate that the estimation process is viable for regions that are better represented in the microdata sample, but also revealed the possibility of strong overfitting in sparsely sampled sub-populations.« less

Validation of spatiodemographic estimates produced through data fusion of small area census records and household microdata

DOE PAGES

Rose, Amy N.; Nagle, Nicholas N.

2016-08-01

Techniques such as Iterative Proportional Fitting have been previously suggested as a means to generate new data with the demographic granularity of individual surveys and the spatial granularity of small area tabulations of censuses and surveys. This article explores internal and external validation approaches for synthetic, small area, household- and individual-level microdata using a case study for Bangladesh. Using data from the Bangladesh Census 2011 and the Demographic and Health Survey, we produce estimates of infant mortality rate and other household attributes for small areas using a variation of an iterative proportional fitting method called P-MEDM. We conduct an internalmore » validation to determine: whether the model accurately recreates the spatial variation of the input data, how each of the variables performed overall, and how the estimates compare to the published population totals. We conduct an external validation by comparing the estimates with indicators from the 2009 Multiple Indicator Cluster Survey (MICS) for Bangladesh to benchmark how well the estimates compared to a known dataset which was not used in the original model. The results indicate that the estimation process is viable for regions that are better represented in the microdata sample, but also revealed the possibility of strong overfitting in sparsely sampled sub-populations.« less

Radiographic detection of 100 A thickness variations in 1-. mu. m-thick coatings applied to submillimeter-diameter laser fusion targets

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

Stupin, D.M.

1986-01-01

We have developed x-ray radiography to measure thickness variations of coatings on laser fusion targets. Our technique is based on measuring the variation in x-ray transmission through the targets. The simplest targets are hollow glass microshells or microballoons 100 to 500 ..mu..m in diameter, that have several layers of metals or plastics, 1 to 100 ..mu..m thick. Our goal is to examine these opaque coatings for thickness variations as small as 1% or 0.1%, depending on the type of defect. Using contact radiography we have obtained the desired sensitivity for concentric and elliptical defects of 1%. This percentage corresponds tomore » thickness variations as small as 100 A in a 1-..mu..m-thick coating. For warts and dimples, the desired sensitivity is a function of the area of the defect, and we are developing a system to detect 0.1% thickness variations that cover an area 10 ..mu..m by 10 ..mu..m. We must use computer analysis of contact radiographs to measure 1% thickness variations in either concentricity or ellipticity. Because this analysis takes so long on our minicomputer, we preselect the radiographs by looking for defects at the 10% level on a video image analysis system.« less

Design Issues in Small-Area Studies of Environment and Health

PubMed Central

Elliott, Paul; Savitz, David A.

2008-01-01

Background Small-area studies are part of the tradition of spatial epidemiology, which is concerned with the analysis of geographic patterns of disease with respect to environmental, demographic, socioeconomic, and other factors. We focus on etiologic research, where the aim is to make inferences about spatially varying environmental factors influencing the risk of disease. Methods and results We illustrate the approach through three exemplars: a) magnetic fields from overhead electric power lines and the occurrence of childhood leukemia, which illustrates the use of geographic information systems to focus on areas with high exposure prevalence; b) drinking-water disinfection by-products and reproductive outcomes, taking advantage of large between- to within-area variability in exposures from the water supply; and c) chronic exposure to air pollutants and cardiorespiratory health, where issues of socioeconomic confounding are particularly important. Discussion The small-area epidemiologic approach assigns exposure estimates to individuals based on location of residence or other geographic variables such as workplace or school. In this way, large populations can be studied, increasing the ability to investigate rare exposures or rare diseases. The approach is most effective when there is well-defined exposure variation across geographic units, limited within-area variation, and good control for potential confounding across areas. Conclusions In conjunction with traditional individual-based approaches, small-area studies offer a valuable addition to the armamentarium of the environmental epidemiologist. Modeling of exposure patterns coupled with collection of individual-level data on subsamples of the population should lead to improved risk estimates (i.e., less potential for bias) and help strengthen etiologic inference. PMID:18709174

Small-scale density variations in the lunar crust revealed by GRAIL

NASA Astrophysics Data System (ADS)

Jansen, J. C.; Andrews-Hanna, J. C.; Li, Y.; Lucey, P. G.; Taylor, G. J.; Goossens, S.; Lemoine, F. G.; Mazarico, E.; Head, J. W.; Milbury, C.; Kiefer, W. S.; Soderblom, J. M.; Zuber, M. T.

2017-07-01

Data from the Gravity Recovery and Interior Laboratory (GRAIL) mission have revealed that ∼98% of the power of the gravity signal of the Moon at high spherical harmonic degrees correlates with the topography. The remaining 2% of the signal, which cannot be explained by topography, contains information about density variations within the crust. These high-degree Bouguer gravity anomalies are likely caused by small-scale (10‧s of km) shallow density variations. Here we use gravity inversions to model the small-scale three-dimensional variations in the density of the lunar crust. Inversion results from three non-descript areas yield shallow density variations in the range of 100-200 kg/m3. Three end-member scenarios of variations in porosity, intrusions into the crust, and variations in bulk crustal composition were tested as possible sources of the density variations. We find that the density anomalies can be caused entirely by changes in porosity. Characteristics of density anomalies in the South Pole-Aitken basin also support porosity as a primary source of these variations. Mafic intrusions into the crust could explain many, but not all of the anomalies. Additionally, variations in crustal composition revealed by spectral data could only explain a small fraction of the density anomalies. Nevertheless, all three sources of density variations likely contribute. Collectively, results from this study of GRAIL gravity data, combined with other studies of remote sensing data and lunar samples, show that the lunar crust exhibits variations in density by ± 10% over scales ranging from centimeters to 100‧s of kilometers.

Small-Scale Density Variations in the Lunar Crust Revealed by GRAIL

NASA Technical Reports Server (NTRS)

Jansen, J. C.; Andrews-Hanna, J. C.; Li, Y.; Lucey, P. G.; Taylor, G. J.; Goossens, S.; Lemoine, F. G.; Mazarico, E.; Head, J. W., III; Milbury, C.;

Invited Talks at Naples and Coimbra

NASA Technical Reports Server (NTRS)

Jordan, Stuart

2003-01-01

Prior to observations of the solar irradiance from space that began in 1979 there was no hope of obtaining even rough estimates of the solar irradiance variation over a solar cycle, since the space observations made since showed that the magnitude of the variation over a cycle to date is less than 0.1 %, a value too small to measure from the ground. At the same time, it would be useful to know the cycle-dependent variation over more than just the two recent cycles. Lacking a complete theory for the solar dynamo responsible for this variation, the current hope is to determine what proxy might yield the best values. Because there is an excellent database on sunspot umbral and penumbral areas from the Greenwich Observatory for the years 1874-1976 (but not beyond), the possibility exists that these data could be used. This talk will summarize results of a joint study in which satellite measurements of the solar irradiance variation are compared with ground-based measurements from the Coimbra Observatory of sunspot number, umbral area, and total sunspot area to determine which would serve as the best proxy for using the Greenwich observations back to 1874. From the near constancy of sunspot umbral magnetic fields upon which the useful parameter photometric sunspot index is based, we expected that umbral area would yield the beat proxy. To our surprise, after performing a statistical study of the observations over the period 1980-1990, preliminary indications are that sunspot number (a parameter available back into the 18th century) may be just as useful as the umbral area. As expected, both are quite superior as proxies to total sunspot area, which includes the penumbral area. This conclusion is consistent with earlier work of Hop and Schatten, who sought a proxy by studies of the umbral-penumbral area ratio. A second motivation for pursuing this work is the possibility that relatively small variations in the solar irradiance may induce larger responses in Earth's climate than would occur from simply introducing the corresponding heat differential into the terrestrial atmosphere. The talk will conclude with a description of why some climatologists are beginning to explore this possibility, which is suggest by some of the space observations used in the above search for a solar irradiance variation proxy.

Small-area estimation of health insurance coverage for California legislative districts.

PubMed

Yu, Hongjian; Meng, Ying-Ying; Mendez-Luck, Carolyn A; Jhawar, Mona; Wallace, Steven P

2007-04-01

To aid state and local policymakers, program planners, and community advocates, we created estimates of the percentage of the population lacking health insurance in small geographic areas of California. Finally, calibration ensured the consistency and stability of the estimates when they were aggregated. Health insurance coverage among nonelderly persons varied widely across assembly districts, from 10% to 44%. The utility of local-level estimates was most apparent when the variations in subcounty uninsured rates in Los Angeles County (19%-44%) were examined. Stable and useful estimates of health insurance rates for small areas such as legislative districts can be created through use of multiple sources of publicly available data.

Vertical-Cavity Surface-Emitting Lasers: Design, Fabrication and Characterization

NASA Astrophysics Data System (ADS)

Geels, Randall Scott

The theory, design, fabrication, and testing of vertical-cavity surface-emitting lasers (VCSELs) is explored in depth. The design of the distributed Bragg reflector (DBR) mirrors is thoroughly treated and both analytic and numerical approaches for computing the reflectivity are covered. The electrical properties of the DBR mirrors are also considered and graded interfaces are found to be critical in reducing the series voltage drop in the mirrors. Thickness variations due to growth rate uncertainties are considered and the permissible thickness inaccuracies are discussed. Layer thickness variations of several percent can be tolerated without large changes in the threshold current. The growth of VCSELs by molecular beam epitaxy (MBE) is described in detail as is the device processing technology for broad area as well as small area devices. Results from numerous devices are reported. Broad area in-plane lasers were used to characterize the material and determine the internal parameters. Broad area VCSELs were fabricated to determine the characteristics of the VCSEL cavity. Small area VCSELs were fabricated and extensively tested. Measured and derived parameters from small area devices include: threshold current (~0.7 mA), peak output power (>3 mW), maximum operation temperature (>110^ circC), output power at 100^ circC (~0.4 mW), and linewidth (85 MHz). The near field, far field, and polarization characteristics were also measured.

Geographic Variation in the Use of Adjuvant Therapy among Elderly Patients with Resected Non-Small Cell Lung Cancer

PubMed Central

Tien, Yu-Yu; Wright, Kara; Halfdanarson, Thorvardur R.; Abu-Hejleh, Taher; Brooks, John M.

2016-01-01

Objectives The purpose of this study was to assess to what extent geographic variation in adjuvant treatment for non-small cell lung cancer (NSCLC) patients would remain, after controlling for patient and area-level characteristics. Materials and Methods A retrospective cohort of 18,410 Medicare beneficiaries with resected, stage I-IIIA NSCLC was identified from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. Adjuvant therapies were classified as adjuvant chemotherapy (ACT), postoperative radiation therapy (PORT), or no adjuvant therapy. Predicted treatment probabilities were estimated for each patient given their clinical, demographic, and area-level characteristics with multivariate logistic regression. Area Treatment Ratios were used to estimate the propensity of patients in a local area to receive an adjuvant treatment, controlling for characteristics of patients in the area. Areas were categorized as low-, mid- and high-use and mapped for two representative SEER registries. Results Overall, 10%, 12%, and 78% of patients received ACT, PORT and no adjuvant therapy, respectively. Age, sex, stage, type and year of surgery, and comorbidity were associated with adjuvant treatment use. Even after adjusting for patient characteristics, substantial geographic treatment variation remained. High- and low-use areas were tightly juxtaposed within and across SEER registries, often within the same county. In some local areas, patients were up to eight times more likely to receive adjuvant therapy than expected, given their characteristics. On the other hand, almost a quarter of patients lived in local areas in which patients were more than three times less likely to receive ACT than would be predicted. Conclusion Controlling for patient and area-level covariates did not remove geographic variation in adjuvant therapies for resected NSCLC patients. A greater proportion of patients were treated less than expected, rather than more than expected. Further research is needed to better understand its causes and potential impact on outcomes. PMID:27040848

Variation in geographic access to specialist inpatient hospices in England and Wales.

PubMed

Gatrell, Anthony C; Wood, D Justin

2012-07-01

We seek to map and describe variation in geographic access to the set of 189 specialist adult inpatient hospices in England and Wales. Using almost 35,000 small Census areas (Local Super Output Areas: LSOAs) as our units of analysis, the locations of hospices, and estimated drive times from LSOAs to hospices we construct an accessibility 'score' for each LSOA, for England and Wales as a whole. Data on cancer mortality are used as a proxy for the 'demand' for hospice care and we then identify that subset of small areas in which accessibility (service supply) is relatively poor yet the potential 'demand' for hospice services is above average. That subset is then filtered according to the deprivation score for each LSOA, in order to identify those LSOAs which are also above average in terms of deprivation. While urban areas are relatively well served, large parts of England and Wales have poor access to hospices, and there is a risk that the needs of those living in relatively deprived areas may be unmet. Copyright © 2012 Elsevier Ltd. All rights reserved.

A multilevel model for cardiovascular disease prevalence in the US and its application to micro area prevalence estimates.

PubMed

Congdon, Peter

2009-01-30

Estimates of disease prevalence for small areas are increasingly required for the allocation of health funds according to local need. Both individual level and geographic risk factors are likely to be relevant to explaining prevalence variations, and in turn relevant to the procedure for small area prevalence estimation. Prevalence estimates are of particular importance for major chronic illnesses such as cardiovascular disease. A multilevel prevalence model for cardiovascular outcomes is proposed that incorporates both survey information on patient risk factors and the effects of geographic location. The model is applied to derive micro area prevalence estimates, specifically estimates of cardiovascular disease for Zip Code Tabulation Areas in the USA. The model incorporates prevalence differentials by age, sex, ethnicity and educational attainment from the 2005 Behavioral Risk Factor Surveillance System survey. Influences of geographic context are modelled at both county and state level, with the county effects relating to poverty and urbanity. State level influences are modelled using a random effects approach that allows both for spatial correlation and spatial isolates. To assess the importance of geographic variables, three types of model are compared: a model with person level variables only; a model with geographic effects that do not interact with person attributes; and a full model, allowing for state level random effects that differ by ethnicity. There is clear evidence that geographic effects improve statistical fit. Geographic variations in disease prevalence partly reflect the demographic composition of area populations. However, prevalence variations may also show distinct geographic 'contextual' effects. The present study demonstrates by formal modelling methods that improved explanation is obtained by allowing for distinct geographic effects (for counties and states) and for interaction between geographic and person variables. Thus an appropriate methodology to estimate prevalence at small area level should include geographic effects as well as person level demographic variables.

A multilevel model for cardiovascular disease prevalence in the US and its application to micro area prevalence estimates

PubMed Central

Congdon, Peter

2009-01-01

Background Estimates of disease prevalence for small areas are increasingly required for the allocation of health funds according to local need. Both individual level and geographic risk factors are likely to be relevant to explaining prevalence variations, and in turn relevant to the procedure for small area prevalence estimation. Prevalence estimates are of particular importance for major chronic illnesses such as cardiovascular disease. Methods A multilevel prevalence model for cardiovascular outcomes is proposed that incorporates both survey information on patient risk factors and the effects of geographic location. The model is applied to derive micro area prevalence estimates, specifically estimates of cardiovascular disease for Zip Code Tabulation Areas in the USA. The model incorporates prevalence differentials by age, sex, ethnicity and educational attainment from the 2005 Behavioral Risk Factor Surveillance System survey. Influences of geographic context are modelled at both county and state level, with the county effects relating to poverty and urbanity. State level influences are modelled using a random effects approach that allows both for spatial correlation and spatial isolates. Results To assess the importance of geographic variables, three types of model are compared: a model with person level variables only; a model with geographic effects that do not interact with person attributes; and a full model, allowing for state level random effects that differ by ethnicity. There is clear evidence that geographic effects improve statistical fit. Conclusion Geographic variations in disease prevalence partly reflect the demographic composition of area populations. However, prevalence variations may also show distinct geographic 'contextual' effects. The present study demonstrates by formal modelling methods that improved explanation is obtained by allowing for distinct geographic effects (for counties and states) and for interaction between geographic and person variables. Thus an appropriate methodology to estimate prevalence at small area level should include geographic effects as well as person level demographic variables. PMID:19183458

Small-area variation in screening for cancer, glucose and cholesterol in Ontario: a cross-sectional study.

PubMed

Fernandes, Kimberly A; Sutradhar, Rinku; Borkhoff, Cornelia M; Baxter, Nancy; Lofters, Aisha; Rabeneck, Linda; Tinmouth, Jill; Paszat, Lawrence

2015-01-01

Screening for cervical, breast and colon cancers, and elevations of cholesterol and glucose, reduces premature cause-specific mortality from these cancers and circulatory diseases. Despite primary care reforms and incentives, and promotion of cancer-screening programs among individuals, participation is suboptimal. We aimed to examine participation as of Dec. 31, 2011, by factors of deprivation, demographics and primary care at the small-area level. From health care administrative databases, we identified people eligible for each screening test, and their participation, in each dissemination area (referred to as small areas, n = 18 950) in Ontario. We calculated rates for each test among small areas (overall and stratified by demographic, socioeconomic and primary care descriptors) and stratified by sex for all tests combined. We loaded all data into a geographic information system. Funnel plots were generated showing the percentage of eligible people who completed screening for all tests by small area, stratified by sex. Overall and stratified screening prevalence ratios were calculated among small areas. Among small areas, the mean and SD for participation in all tests combined was 31.6% (SD 11.0%) for women and 41.2% (SD 12.0%) for men. Screening prevalence among small areas, for each test and for all tests combined, overall and stratified by sex, declined with decreasing percentage with high school completion, decreasing socioeconomic quintile, and decreasing percentage with an identifiable primary care physician. Our results show that the rate of participation in all eligible screening tests among small areas is much lower than the rate of participation in any one particular test. This finding has implications for the design and implementation of strategies to improve rates of screening.

Acquisition of Content Area Vocabulary for Students with Learning Disabilities.

ERIC Educational Resources Information Center

Keel, Marie C.; Slaton, Deborah Bott; Blackhurt, A. Edward

2001-01-01

This study compared effects of two variations of the constant-time-delay (CTD) procedure on the observational learning of content area vocabulary by seven primary grade students with learning disabilities in a small group instructional setting. Both conditions (every student writes all words or only target student writes) were equally effective…

Area-level variations in cancer care and outcomes.

PubMed

Keating, Nancy L; Landrum, Mary Beth; Lamont, Elizabeth B; Bozeman, Samuel R; McNeil, Barbara J

2012-05-01

: Substantial regional variations in health-care spending exist across the United States; yet, care and outcomes are not better in higher-spending areas. Most studies have focused on care in fee-for-service Medicare; whether spillover effects exist in settings without financial incentives for more care is unknown. : We studied care for cancer patients in fee-for-service Medicare and the Veterans Health Administration (VA) to understand whether processes and outcomes of care vary with area-level Medicare spending. : An observational study using logistic regression to assess care by area-level measures of Medicare spending. : Patients with lung, colorectal, or prostate cancers diagnosed during 2001-2004 in Surveillance, Epidemiology, and End Results (SEER) areas or the VA. The SEER cohort included fee-for-service Medicare patients aged older than 65 years. : Recommended and preference-sensitive cancer care and mortality. : In fee-for-service Medicare, higher-spending areas had higher rates of recommended care (curative surgery and adjuvant chemotherapy for early-stage non-small-cell lung cancer and chemotherapy for stage III colon cancer) and preference-sensitive care (chemotherapy for stage IV lung and colon cancer and primary treatment of local/regional prostate cancer) and had lower lung cancer mortality. In the VA, we observed minimal variation in care by area-level Medicare spending. : Our findings suggest that intensity of care for Medicare beneficiaries is not driving variations in VA care, despite some overlap in physician networks. Although the Dartmouth Atlas work has been of unprecedented importance in demonstrating variations in Medicare spending, new measures may be needed to better understand variations in other populations.

GRACE Hydrological estimates for small basins: Evaluating processing approaches on the High Plains Aquifer, USA

NASA Astrophysics Data System (ADS)

Longuevergne, Laurent; Scanlon, Bridget R.; Wilson, Clark R.

2010-11-01

The Gravity Recovery and Climate Experiment (GRACE) satellites provide observations of water storage variation at regional scales. However, when focusing on a region of interest, limited spatial resolution and noise contamination can cause estimation bias and spatial leakage, problems that are exacerbated as the region of interest approaches the GRACE resolution limit of a few hundred km. Reliable estimates of water storage variations in small basins require compromises between competing needs for noise suppression and spatial resolution. The objective of this study was to quantitatively investigate processing methods and their impacts on bias, leakage, GRACE noise reduction, and estimated total error, allowing solution of the trade-offs. Among the methods tested is a recently developed concentration algorithm called spatiospectral localization, which optimizes the basin shape description, taking into account limited spatial resolution. This method is particularly suited to retrieval of basin-scale water storage variations and is effective for small basins. To increase confidence in derived methods, water storage variations were calculated for both CSR (Center for Space Research) and GRGS (Groupe de Recherche de Géodésie Spatiale) GRACE products, which employ different processing strategies. The processing techniques were tested on the intensively monitored High Plains Aquifer (450,000 km2 area), where application of the appropriate optimal processing method allowed retrieval of water storage variations over a portion of the aquifer as small as ˜200,000 km2.

From data to decisions? Exploring how healthcare payers respond to the NHS Atlas of Variation in Healthcare in England.

PubMed

Schang, Laura; Morton, Alec; DaSilva, Philip; Bevan, Gwyn

2014-01-01

Although information on variations in health service performance is now more widely available, relatively little is known about how healthcare payers use this information to improve resource allocation. We explore to what extent and how Primary Care Trusts (PCTs) in England have used the NHS Atlas of Variation in Healthcare, which has highlighted small area variation in rates of expenditure, activity and outcome. Data collection involved an email survey among PCT Chief Executives and a telephone follow-up to reach non-respondents (total response: 53 of 151 of PCTs, 35%). 45 senior to mid-level staff were interviewed to probe themes emerging from the survey. The data were analysed using a matrix-based Framework approach. Just under half of the respondents (25 of 53 PCTs) reported not using the Atlas, either because they had not been aware of it, lacked staff capacity to analyse it, or did not perceive it as applicable to local decision-making. Among the 28 users, the Atlas served as a prompt to understand variations and as a visual tool to facilitate communication with clinicians. Achieving clarity on which variations are unwarranted and agreeing on responsibilities for action appeared to be important factors in moving beyond initial information gathering towards decisions about resource allocation and behaviour change. Many payers were unable to use information on small area variations in expenditure, activity and outcome. To change this what is additionally required are appropriate tools to understand causes of unexplained variation, in particular unwarranted variation, and enable remedial actions to be prioritised in terms of their contribution to population health. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Natal movement in juvenile Atlantic salmon: a body size-dependent strategy?

Treesearch

Sigurd Einum; Anders G. Finstad; Grethe Robertsen; Keith H. Nislow; Simon McKelvey; John D. Armstrong

2012-01-01

If competitive ability depends on body size, then the optimal natal movement from areas of high local population density can also be predicted to be size-dependent. Specifically, small, competitively-inferior individuals would be expected to benefit most from moving to areas of lower local density. Here we evaluate whether individual variation in natal movement...

Variations in Divorce Rates by Community Size: A Test of the Social Integration Explanation.

ERIC Educational Resources Information Center

Shelton, Beth Anne

1987-01-01

Found a strong correlation between residential mobility rate and a measure of marital dissolution. Concluded that community size and marital dissolution correlated positively because of higher levels of residential mobility in large cities and urban areas than in small cities and rural areas. Found high residential mobility both an indicator and a…

Sampling throughfall and stemflow in young loblolly pine plantations

Treesearch

S.J. Zarnoch; D.A. Abrahamson; P.M. Dougherty

2002-01-01

Throughfall and stemflow estimates were obtained on a rain-event basis for small (0.09-hectare) plots established in a young loblolly pine (Pinus taeda L.) plantation in North Carolina. The plots were exposed to specific fertilization and irrigation treatments, which resulted in a wide range of basal areas and leaf area indices. Coefficients of variation were also...

[Responses of Picea likiangensis radial growth to climate change in the Small Zhongdian area of Yunnan Province, Southwest China].

PubMed

Zhao, Zhi-Jiang; Tan, Liu-Yi; Kang, Dong-Wei; Liu, Qi-Jing; Li, Jun-Qing

2012-03-01

Picea likiangensis (Franch. ) Pritz. primary forest is one of the dominant forest types in the Small Zhongdian area in Shangri-La County of Yunnan Province. In this paper, the responses of P. likiangensis tree-ring width to climate change were analyzed by dendrochronological methods, and the dendrochronology was built by using relatively conservative detrending negative exponential curves or linear regression. Correlation analysis and response function analysis were applied to explore the relationships between the residual chronology series (RES) and climatic factors at different time scales, and pointer year analysis was used to explain the reasons of producing narrow and wide rings. In the study area, the radial growth of P. likiangensis and the increasing air temperature from 1990 to 2008 had definite 'abruption'. The temperature and precipitation in previous year growth season were the main factors limiting the present year radial growth, and especially, the temperature in previous July played a negative feedback role in the radial growth, while the sufficient precipitation in previous July promoted the radial growth. The differences in the temperature variation and precipitation variation in previous year were the main reasons for the formation of narrow and wide rings. P. likiangensis radial growth was not sensitive to the variation of PDSI.

Surface charging of a crater near lunar terminator

NASA Astrophysics Data System (ADS)

Anuar, A. K.

2017-05-01

Past lunar missions have shown the presence of dust particles in the lunar exosphere. These particles originate from lunar surface and are due to the charging of lunar surface by the solar wind and solar UV flux. Near the lunar terminator region, the low conductivity of the surface and small scale variations in surface topology could cause the surface to charge to different surface potentials. This paper simulates the variation of surface potential for a crater located in the lunar terminator regions using Spacecraft Plasma Interaction Software (SPIS). SPIS employs particle in cell method to simulate the motion of solar wind particles and photoelectrons. Lunar crater has been found to create mini-wake which affects both electron and ion density and causes small scale potential differences. Simulation results show potential difference of 300 V between sunlit area and shadowed area which creates suitable condition for dust levitation to occur.

Exploring factors controlling the variability of pesticide concentrations in the Willamette River Basin using tree-based models

USGS Publications Warehouse

Qian, S.S.; Anderson, Chauncey W.

1999-01-01

We analyzed available concentration data of five commonly used herbicides and three pesticides collected from small streams in the Willamette River Basin in Oregon to identify factors that affect the variation of their concentrations in the area. The emphasis of this paper is the innovative use of classification and regression tree models for exploratory data analysis as well as analyzing data with a substantial amount of left-censored values. Among variables included in this analysis, land-use pattern in the watershed is the most important for all but one (simazine) of the eight pesticides studied, followed by geographic location, intensity of agriculture activities in the watershed (represented by nutrient concentrations in the stream), and the size of the watershed. The significant difference between urban sites and agriculture sites is the variability of stream concentrations. While all 16 nonurban watersheds have significantly higher variation than urban sites, the same is not necessarily true for the mean concentrations. Seasonal variation accounts for only a small fraction of the total variance in all eight pesticides.We analyzed available concentration data of five commonly used herbicides and three pesticides collected from small streams in the Willamette River Basin in Oregon to identify factors that affect the variation of their concentrations in the area. The emphasis of this paper is the innovative use of classification and regression tree models for exploratory data analysis as well as analyzing data with a substantial amount of left-censored values. Among variables included in this analysis, land-use pattern in the watershed is the most important for all but one (simazine) of the eight pesticides studied, followed by geographic location, intensity of agriculture activities in the watershed (represented by nutrient concentrations in the stream), and the size of the watershed. The significant difference between urban sites and agriculture sites is the variability of stream concentrations. While all 16 nonurban watersheds have significantly higher variation than urban sites, the same is not necessarily true for the mean concentrations. Seasonal variation accounts for only a small fraction of the total variance in all eight pesticides.

Effects of Small Oscillations on the Effective Area

NASA Astrophysics Data System (ADS)

Cotroneo, V.; Conconi, P.; Cusumano, G.; Pareschi, G.; Spiga, D.; Tagliaferri, G.

2009-05-01

We analyze the effective area of the Simbol-X mirrors as a function of the off-axis angle for small oscillations. A reduction is expected due to: 1) geometrical effects, because some of the photons miss the secondary mirror surface; 2) reflectivity effects, caused by the variation of the coating reflectivity with the incidence angle. The former are related to the length of the two mirror surfaces, and can be reduced by making the secondary mirror longer. The second ones are energy-dependent, and strongly related to the characteristics of the reflecting coating. These effects are analyzed by means of ray-tracing simulations in order to optimize the mirror and coating design, aiming to improve the effective area stability.

Linked hydrologic and climate variations in British Columbia and Yukon.

PubMed

Whitfield, P H

2001-01-01

Climatic and hydrologic variations between the decades 1976-1985 and 1986-1995 are examined at 34 climate stations and 275 hydrology stations. The variations in climate are distributed across a broad spatial area. Temperatures were generally warmer in the most recent decade, with many stations showing significant increases during the spring and fall. No significant decreases in temperature were found. Significant increases in temperature were more frequent in the south than in the northern portions of the region. Significant changes in precipitation were also more prevalent in the south. In coastal areas, there were significant decreases in precipitation during the dry season, and significant increases during the wet season. In the BC interior, significant precipitation decreases occurred during the fall, with significant increases during the winter and spring. In the north there were few changes in precipitation. The hydrologic responses to these variations in climate follow six distinctive patterns. The spatial distribution of these patterns suggests that in different ecozones, small variations in climate, particularly temperature, elicit different hydrologic responses.

Collapse of a pollination web in small conservation areas.

PubMed

Pauw, Anton

2007-07-01

A suspected global decline in pollinators has heightened interest in their ecological significance. In a worst-case scenario, the decline of generalist pollinators is predicted to trigger cascades of linked declines among the multiple specialist plant species to which they are linked, but this has not been documented. I studied a portion of a pollination web involving a generalist pollinator, the oil-collecting bee Rediviva peringueyi, and a community of oil-secreting plants. Across 27 established conservation areas located in the Cape Floral Region, I found substantial variation in the bees' occurrence in relation to soil type and the successional stage of the vegetation. Anthropogenic declines were detectable against this background of naturally occurring variation: R. peringueyi was absent from small conservation areas (< 385 ha) in an urban matrix. In the absence of the bee, seed set failed in six specialist plant species that are pollinated only by R. peringueyi but remained high in a pollination generalist, which had replacement pollinators. The findings are consistent with theoretical predictions of the importance of generalist pollinators in maintaining the structure of pollination webs.

VARIATION OF PATHOGEN DENSITIES IN URBAN STORMWATER RUNOFF WITH LAND USE

EPA Science Inventory

Stormwater runoff samples were collected from outfalls draining small municipal separate storm sewer systems. The samples were collected from three land use areas (high-density residential, low-density residential, and landscaped commercial). The concentrations of organisms in ...

VARIATION OF PATHOGEN DENSITITES IN URBAN STORMWATER RUNOFF WITH LAND USE

EPA Science Inventory

Stormwater runoff samples were collected from outfalls draining small municipal separate storm sewer systems. The samples were collected from three land use areas (high-density residential, low-density residential, and landscaped commercial). The concentrations of organisms in ...

Changes in the area of inland lakes in arid regions of central Asia during the past 30 years.

PubMed

Bai, Jie; Chen, Xi; Li, Junli; Yang, Liao; Fang, Hui

2011-07-01

Inland lakes are major surface water resource in arid regions of Central Asia. The area changes in these lakes have been proved to be the results of regional climate changes and recent human activities. This study aimed at investigating the area variations of the nine major lakes in Central Asia over the last 30 years. Firstly, multi-temporal Landsat imagery in 1975, 1990, 1999, and 2007 were used to delineate lake extents automatically based on Normalized Difference Water Index (NDWI) threshold segmentation, then lake area variations were detailed in three decades and the mechanism of these changes was analyzed with meteorological data and hydrological data. The results indicated that the total surface areas of these nine lakes had decreased from 91,402.06 km(2) to 46,049.23 km(2) during 1975-2007, accounting for 49.62% of their original area of 1975. Tail-end lakes in flat areas had shrunk dramatically as they were induced by both climate changes and human impacts, while alpine lakes remained relatively stable due to the small precipitation variations. With different water usage of river outlets, the variations of open lakes were more flexible than those of other two types. According to comprehensive analyses, different types of inland lakes presented different trends of area changes under the background of global warming effects in Central Asia, which showed that the increased human activities had broken the balance of water cycles in this region.

Matching Deep Tow Camera study and Sea Floor geochemical characterization of gas migration at the Tainan Ridge, South China Sea

NASA Astrophysics Data System (ADS)

Fan, L. F.; Lien, K. L.; Hsieh, I. C.; Lin, S.

2017-12-01

Methane seep in deep sea environment could lead to build up of chemosynthesis communities, and a number of geological and biological anomalies as compare to the surrounding area. In order to examine the linkage between seep anomalies and those at the vicinity background area, and to detail mapping those spatial variations, we used a deep towed camera system (TowCam) to survey seafloor on the Tainan Ridge, Northeastern South China Sea (SCS). The underwater sea floor pictures could provide better spatial variations to demonstrate impact of methane seep on the sea floor. Water column variations of salinity, temperature, dissolved oxygen were applied to delineate fine scale variations at the study area. In addition, sediment cores were collected for chemical analyses to confirm the existence of local spatial variations. Our results show large spatial variations existed as a result of differences in methane flux. In fact, methane is the driving force for the observed biogeochemical variations in the water column, on the sea floor, and in the sediment. Of the area we have surveyed, there are approximately 7% of total towcam survey data showing abnormal water properties. Corresponding to the water column anomalies, underwater sea floor pictures taken from those places showed that chemosynthetic clams and muscles could be identified, together with authigenic carbonate buildups, and bacterial mats. Moreover, sediment cores with chemical anomalies also matched those in the water column and on the sea floor. These anomalies, however, represent only a small portion of the area surveyed and could not be identified with typical (random) coring method. Methane seep, therefore, require tedious and multiple types of surveys to better understand the scale and magnitude of seep and biogeochemical anomalies those were driven by gas migrations.

High Bee and Wasp Diversity in a Heterogeneous Tropical Farming System Compared to Protected Forest

PubMed Central

Schüepp, Christof; Rittiner, Sarah; Entling, Martin H.

2012-01-01

It is a globally important challenge to meet increasing demands for resources and, at the same time, protect biodiversity and ecosystem services. Farming is usually regarded as a major threat to biodiversity due to its expansion into natural areas. We compared biodiversity of bees and wasps between heterogeneous small-scale farming areas and protected forest in northern coastal Belize, Central America. Malaise traps operated for three months during the transition from wet to dry season. Farming areas consisted of a mosaic of mixed crop types, open habitat, secondary forest, and agroforestry. Mean species richness per site (alpha diversity), as well as spatial and temporal community variation (beta diversity) of bees and wasps were equal or higher in farming areas compared to protected forest. The higher species richness and community variation in farmland was due to additional species that did not occur in the forest, whereas most species trapped in forest were also found in farming areas. The overall regional species richness (gamma diversity) increased by 70% with the inclusion of farming areas. Our results suggest that small-scale farming systems adjacent to protected forest may not only conserve, but even favour, biodiversity of some taxonomic groups. We can, however, not exclude possible declines of bee and wasp diversity in more intensified farmland or in landscapes completely covered by heterogeneous farming systems. PMID:23300598

VARIATIONS OF MICROORGANISM CONCENTRATIONS IN URBAN STORMWATER RUNOFF WITH LAND USE AND SEASONS

EPA Science Inventory

Stormwater runoff samples were collected from outfalls draining small municipal separate storm sewer systems. The samples were collected from three different land use areas based on local designation (high-density residential, low-density residential, and landscaped commercial)....

Assaults, murders and walkers: The impact of violent crime on physical activity.

PubMed

Janke, Katharina; Propper, Carol; Shields, Michael A

2016-05-01

We investigate an underexplored externality of crime: the impact of violent crime on individuals' participation in walking. For many adults walking is the only regular physical activity. We use a sample of nearly 1 million people in 323 small areas in England between 2005 and 2011 matched to quarterly crime data at the small area level. Within area variation identifies the causal effect of local violent crime on walking and a difference-in-difference analysis of two high-profile crimes corroborates our results. We find a significant deterrent effect of violent crime on walking that translates into a drop in overall physical activity. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Factors associated with suicidal ideation: the role of context.

PubMed

Han, Sehee; Lee, Hee-Sun

2013-06-01

No previous study could be found that examined the longitudinal association between suicidal ideation and the factors associated with it and that considered both individual and contextual characteristics simultaneously. This study examined whether variation in suicidal ideation is attributable to the administrative-area level and examined suicidal ideation and the factors associated with it at multiple levels, especially focusing on social capital. Longitudinal data of 5222 individuals and 2741 households in 25 administrative areas from the Wave 1 and Wave 2 of the Seoul Welfare Panel Study were used. In the study, 2.7% of variation in suicidal ideation was attributable to the administrative area. The results also suggested that perceived helpfulness at individual level (odds ratio (OR) = 0.60; 95% confidence interval (CI) = 0.43, 0.83) and organizational participation at administrative-area level were associated with suicidal ideation (OR = 0.73; 95% CI = 0.53, 0.99). Policy makers should consider laying down policies aimed at preventing suicide at administrative-area level as suicidal ideation of individuals is different between administrative areas. However, it should also be recognized that directing attention solely at administrative-area level is not efficient, as only small variations in suicidal ideation are attributable to this level. Decision makers need to consider policies promoting social capital, as it may play a role in reducing suicide risk.

Anatomical variations in the pattern of the right hepatic veins draining the posterior segment of the right lobe of the liver.

PubMed

Shilal, Poonam; Tuli, Anita

2015-03-01

The pattern of drainage in the right posterior lobe of liver varies considerably. The knowledge of this variation is very important while performing various surgeries on the right posterior lobe. A study was conducted to see the variations in the pattern of drainage of posterior segment of the right lobe of liver. The aim was to see the variations of right hepatic vein and small accessory hepatic veins draining the posterior segment, the presence of which led to modifications in drainage of posterior segment. Sixty formalin fixed adult human liver specimens were dissected manually. According to the pattern of drainage of tributaries of right hepatic vein, the right hepatic vein was classified into type I, type II, type III and type IV. According to presence of inferior right hepatic vein, three types of drainage of posterior lobe were seen: Type I, (76.36%) right hepatic vein was large, draining wide area of posterior segment. A small inferior right hepatic vein drained the small area of posterior segment. In Type II, (19.92%) both right hepatic and inferior right hepatic veins were medium sized draining the posteroinferior segment of the right lobe concomitantly. In Type III, (32%) accessory veins, the middle right hepatic vein drained the posterosuperior (VII) as well as the posteroinferior (VI) segment. In one specimen, there were numerous middle right hepatic veins draining the right posterior segment. The knowledge of anatomic relationship of veins draining right lobe, is important in performing right posterior segmentectomy. For safe resection of the liver, the complex anatomy of the distribution of the tributaries of the right hepatic vein and the accessory veins have to be studied prior to any surgery done on liver.

Microstructure characterization of 316L deformed at high strain rates using EBSD

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

Yvell, K., E-mail: kyv@du.se

2016-12-15

Specimens from split Hopkinson pressure bar experiments, at strain rates between ~ 1000–9000 s{sup −1} at room temperature and 500 °C, have been studied using electron backscatter diffraction. No significant differences in the microstructures were observed at different strain rates, but were observed for different strains and temperatures. Size distribution for subgrains with boundary misorientations > 2° can be described as a bimodal lognormal area distribution. The distributions were found to change due to deformation. Part of the distribution describing the large subgrains decreased while the distribution for the small subgrains increased. This is in accordance with deformation being heterogeneousmore » and successively spreading into the undeformed part of individual grains. The variation of the average size for the small subgrain distribution varies with strain but not with strain rate in the tested interval. The mean free distance for dislocation slip, interpreted here as the average size of the distribution of small subgrains, displays a variation with plastic strain which is in accordance with the different stages in the stress-strain curves. The rate of deformation hardening in the linear hardening range is accurately calculated using the variation of the small subgrain size with strain. - Highlights: •Only changes in strain, not strain rate, gave differences in the microstructure. •A bimodal lognormal size distribution was found to describe the size distribution. •Variation of the subgrain fraction sizes agrees with models for heterogeneous slip. •Variation of subgrain size with strain describes part of the stress strain curve.« less

Aspects of heterogeneity in the distribution of diversity of the European herpetofauna

NASA Astrophysics Data System (ADS)

Meliadou, Alexandra; Troumbis, Andreas Y.

In the western Palearctic, species richness decreases with increasing latitude for amphibians and reptiles. Hotspots are found in the southermost parts of the area for reptiles, while for amphibians they are in western middle latitude parts. Rapoport's rule predicts that species range increases with latitude and that hotspots contain many species of small range. Both prediction are upheld in the case of reptiles, but the hotspots for amphibians contain mostly widespread species. Most amphibian species of small range are found in southern areas. The seasonal climatic variation hypothesis that has been proposed as an explanation for Rapoport's rule is not verified for the Palearctic herpetofauna.

Variations in fresh fruit and vegetable quality by store type, urban-rural setting and neighbourhood deprivation in Scotland.

PubMed

Cummins, Steven; Smith, Dianna M; Taylor, Mathew; Dawson, John; Marshall, David; Sparks, Leigh; Anderson, Annie S

2009-11-01

Neighbourhood differences in access to fresh fruit and vegetables may explain social inequalities in diet. Investigations have focused on variations in cost and availability as barriers to the purchase and consumption of fresh produce; investigations of quality have been neglected. Here we investigate whether produce quality systematically varies by food store type, rural-urban location and neighbourhood deprivation in a selection of communities across Scotland. Cross-sectional survey of twelve fresh fruit and vegetable items in 288 food stores in ten communities across Scotland. Communities were selected to reflect a range of urban-rural settings and a food retail census was conducted in each location. The quality of twelve fruit and vegetable items within each food store was evaluated. Data from the Scottish Executive were used to characterise each small area by deprivation and urban-rural classification. Scotland. Quality of fruit and vegetables within the surveyed stores was high. Medium-sized stores, stores in small town and rural areas, and stores in more affluent areas tended to have the highest-quality fresh fruit and vegetables. Stores where food is secondary, stores in urban settings and stores in more deprived areas tended have the lowest-quality fresh produce. Although differences in quality were not always statistically significant, patterns were consistent for the majority of fruit and vegetable items. The study provides evidence that variations in food quality may plausibly be a micro-environmental mediating variable in food purchase and consumption and help partially explain neighbourhood differences in food consumption patterns.

Small-scale response in an avian community to a large-scale thinning project in the southwestern United States

Treesearch

Karen E. Bagne; Deborah M. Finch

2009-01-01

Avian populations were monitored using point counts from 2002 to 2007, two years before and four years after a 2800 ha fuel reduction project. The study area was within a ponderosa pine forest near Santa Fe, New Mexico, USA. Adjacent unthinned areas were also monitored as a reference for population variation related to other factors. For individual bird species...

Soil Nutrient Content Influences the Abundance of Soil Microbes but Not Plant Biomass at the Small-Scale

PubMed Central

Koorem, Kadri; Gazol, Antonio; Öpik, Maarja; Moora, Mari; Saks, Ülle; Uibopuu, Annika; Sõber, Virve; Zobel, Martin

2014-01-01

Small-scale heterogeneity of abiotic and biotic factors is expected to play a crucial role in species coexistence. It is known that plants are able to concentrate their root biomass into areas with high nutrient content and also acquire nutrients via symbiotic microorganisms such as arbuscular mycorrhizal (AM) fungi. At the same time, little is known about the small-scale distribution of soil nutrients, microbes and plant biomass occurring in the same area. We examined small-scale temporal and spatial variation as well as covariation of soil nutrients, microbial biomass (using soil fatty acid biomarker content) and above- and belowground biomass of herbaceous plants in a natural herb-rich boreonemoral spruce forest. The abundance of AM fungi and bacteria decreased during the plant growing season while soil nutrient content rather increased. The abundance of all microbes studied also varied in space and was affected by soil nutrient content. In particular, the abundance of AM fungi was negatively related to soil phosphorus and positively influenced by soil nitrogen content. Neither shoot nor root biomass of herbaceous plants showed any significant relationship with variation in soil nutrient content or the abundance of soil microbes. Our study suggests that plants can compensate for low soil phosphorus concentration via interactions with soil microbes, most probably due to a more efficient symbiosis with AM fungi. This compensation results in relatively constant plant biomass despite variation in soil phosphorous content and in the abundance of AM fungi. Hence, it is crucial to consider both soil nutrient content and the abundance of soil microbes when exploring the mechanisms driving vegetation patterns. PMID:24637633

Using mobile monitoring to visualise diurnal variation of traffic pollutants across two near-highway neighbourhoods

NASA Astrophysics Data System (ADS)

Pattinson, Woodrow; Longley, Ian; Kingham, Simon

2014-09-01

It is widely accepted that concentrations of primary traffic pollutants can vary substantially across relatively small urban areas. Fixed-site monitors have been shown to be largely inadequate for representing concentrations at nearby locations, resulting in the increasing use of spatial modelling or mobile sampling methods to achieve spatial saturation. In this study, we employ the use of a simple bicycle to sample concentrations of ultrafine particles (UFPs), carbon monoxide (CO) and particulate matter (PM10) at two small areas (<2.5 km2) in South Auckland, New Zealand. Portable instruments were mounted inside a custom-built casing at the front of the bicycle and every street within each study area was sampled in a grid-like fashion, at four times of day (07:00, 12:00, 17:00 and 22:00). Each area has a six-lane highway running through its centre and the core aim was to visualise and describe spatial variability of pollutant levels about the highway, main arterials and quieter streets, at periods of contrasting meteorological and traffic conditions. A total of 20 sampling runs in each area (five at each of the four timings) were conducted. Meteorological data were logged continuously at background sites within each study area. Results show that the influence of highway traffic (UFPs, CO) was strongest during the mornings and late evenings when wind speeds were low, while for the midday and afternoon timings, concentrations were highest at the arterial and shopping zones. Concentrations of PM10 appeared to be strongest in the residential areas during mornings and late evenings, suggesting an influence of wood burning for home heating. For all timings combined, for all three pollutants, it appears the arterial roads featuring shops and numerous intersections with traffic lights, had a stronger influence on concentrations than the busier but more free-flowing highways. This study provides not only an insight into microspatial hotspot variation across suburbs, but also how this variation shifts diurnally.

School Politics and Conflict in Racially Isolated Schools.

ERIC Educational Resources Information Center

Michel, George J.

1991-01-01

Compares areas and levels of political conflict in racially isolated school districts by surveying six superintendents from racially isolated African-American schools and six superintendents from racially isolated white schools. Similar issues arise at every conflict level with small variations among issues between African-American and white…

Finding big shots: small-area mapping and spatial modelling of obesity among Swiss male conscripts.

PubMed

Panczak, Radoslaw; Held, Leonhard; Moser, André; Jones, Philip A; Rühli, Frank J; Staub, Kaspar

2016-01-01

In Switzerland, as in other developed countries, the prevalence of overweight and obesity has increased substantially since the early 1990s. Most of the analyses so far have been based on sporadic surveys or self-reported data and did not offer potential for small-area analyses. The goal of this study was to investigate spatial variation and determinants of obesity among young Swiss men using recent conscription data. A complete, anonymized dataset of conscription records for the 2010-2012 period were provided by Swiss Armed Forces. We used a series of Bayesian hierarchical logistic regression models to investigate the spatial pattern of obesity across 3,187 postcodes, varying them by type of random effects (spatially unstructured and structured), level of adjustment by individual (age and professional status) and area-based [urbanicity and index of socio-economic position (SEP)] characteristics. The analysed dataset consisted of 100,919 conscripts, out of which 5,892 (5.8 %) were obese. Crude obesity prevalence increased with age among conscripts of lower individual and area-based SEP and varied greatly over postcodes. Best model's estimates of adjusted odds ratios of obesity on postcode level ranged from 0.61 to 1.93 and showed a strong spatial pattern of obesity risk across the country. Odds ratios above 1 concentrated in central and north Switzerland. Smaller pockets of elevated obesity risk also emerged around cities of Geneva, Fribourg and Lausanne. Lower estimates were observed in North-East and East as well as south of the Alps. Importantly, small regional outliers were observed and patterning did not follow administrative boundaries. Similarly as with crude obesity prevalence, the best fitting model confirmed increasing risk of obesity with age and among conscripts of lower professional status. The risk decreased with higher area-based SEP and, to a lesser degree - in rural areas. In Switzerland, there is a substantial spatial variation in obesity risk among young Swiss men. Small-area estimates of obesity risk derived from conscripts records contribute to its understanding and could be used to design further studies and interventions.

Development of a Small Area Sniffer

NASA Technical Reports Server (NTRS)

Meade, Laurie A.

1995-01-01

The aim of this project is to develop and implement a sniffer that is capable of measuring the mass flow rate of air through a small area of pinholes whose diameters are on the magnitude of thousandths of an inch. The sniffer is used to scan a strip of a leading edge panel, which is being used in a hybrid laminar flow control experiment, in order to survey the variations in the amount of air that passes through the porous surface at different locations. Spanwise scans are taken at different chord locations by increasing the pressure in a control volume that is connected to the sniffer head, and recording the drop in pressure as the air is allowed to flow through the tiny holes. This information is used to obtain the mass flow through the structure. More importantly, the deviations from the mean flow rate are found and used to determine whether there are any significant variations in the flow rate from one area to the next. The preliminary results show little deviation in the spanwise direction. These results are important when dealing with the location and amount of suction that will be applied to the leading edge in the active laminar flow control experiment.

Genetic architecture of kernel composition in global sorghum germplasm

USDA-ARS?s Scientific Manuscript database

Sorghum [Sorghum bicolor (L.) Moench] is an important cereal crop for dryland areas in the United States and for small-holder farmers in Africa. Natural variation of sorghum grain composition (protein, fat, and starch) between accessions can be used for crop improvement, but the genetic controls are...

Atmospheric density (surface). [distribution with altitude at launching bases

NASA Technical Reports Server (NTRS)

Daniels, G. E.; Brown, S. C.

1973-01-01

The variation of the density of the atmosphere at the surface from the average for any one station, and between the areas of interest, is small and should have no important effect on preflight spacecraft operations. The median density at the surface for five test ranges is given.

[Variation characteristics of runoff coefficient of Taizi River basin in 1967-2006].

PubMed

Deng, Jun-Li; Zhang, Yong-Fang; Wang, An-Zhi; Guan, De-Xin; Jin, Chang-Jie; Wu, Jia-Bing

2011-06-01

Based on the daily precipitation and runoff data of six main embranchments (Haicheng River, Nansha River, Beisha River, Lanhe River, Xihe River, and Taizi River south embranchment) of Taizi River basin in 1967-2006, this paper analyzed the variation trend of runoff coefficient of the embranchments as well as the relationship between this variation trend and precipitation. In 1967-2006, the Taizi River south embranchment located in alpine hilly area had the largest mean annual runoff coefficient, while the Haicheng River located in plain area had the relatively small one. The annual runoff coefficient of the embranchments except Nansha River showed a decreasing trend, being more apparent for Taizi River south embranchment and Lanhe River. All the embranchments except Xihe River had an obvious abrupt change in the annual runoff coefficient, and the beginning year of the abrupt change differed with embranchment. Annual precipitation had significant effects on the annual runoff coefficient.

Feral Cats Are Better Killers in Open Habitats, Revealed by Animal-Borne Video.

PubMed

McGregor, Hugh; Legge, Sarah; Jones, Menna E; Johnson, Christopher N

2015-01-01

One of the key gaps in understanding the impacts of predation by small mammalian predators on prey is how habitat structure affects the hunting success of small predators, such as feral cats. These effects are poorly understood due to the difficulty of observing actual hunting behaviours. We attached collar-mounted video cameras to feral cats living in a tropical savanna environment in northern Australia, and measured variation in hunting success among different microhabitats (open areas, dense grass and complex rocks). From 89 hours of footage, we recorded 101 hunting events, of which 32 were successful. Of these kills, 28% were not eaten. Hunting success was highly dependent on microhabitat structure surrounding prey, increasing from 17% in habitats with dense grass or complex rocks to 70% in open areas. This research shows that habitat structure has a profound influence on the impacts of small predators on their prey. This has broad implications for management of vegetation and disturbance processes (like fire and grazing) in areas where feral cats threaten native fauna. Maintaining complex vegetation cover can reduce predation rates of small prey species from feral cat predation.

Spatial variation in attributable risks.

PubMed

Congdon, Peter

2015-01-01

The attributable risk (AR) measures the contribution of a particular risk factor to a disease, and allows estimation of disease rates specific to that risk. While previous studies consider variability in ARs over demographic categories, this paper considers the extent of spatial variability in ARs estimated from multilevel data with confounders both at individual and geographic levels. A case study considers the AR for diabetes in relation to elevated BMI, and area rates for diabetes attributable to excess weight. Contextual adjustment includes known area variables, and unobserved spatially clustered influences, while spatial heterogeneity (effect modification) is considered in terms of varying effects of elevated BMI by neighbourhood deprivation category. The application is to patient register data in London, with clear evidence of spatial variation in ARs, and in small area diabetes rates attributable to excess weight. Copyright © 2015 Elsevier Ltd. All rights reserved.

Origin of the X-ray Spectral Variation and Seemingly Broad Iron Line Strucuture in the Seyfert Galaxies

NASA Astrophysics Data System (ADS)

Ebisawa, Ken; Naoki, Iso

2012-07-01

X-ray intensities and spectra of the Seyfert galaxies are known to be variable. Some of the sources have characteristic seemingly broad iron line structure, and their spectral variations are small in the iron line energy band. MCG-6-30-15 is such an archetypal source, and Miyakawa (2011) proposed a "Variable Partial Covering (VPC)" model to explain its continuum spectral variation, seemingly broad iron line structure, and small spectral variation in the iron energy band simultaneously, only due to variation of a single parameter. That single parameter is the "partial covering fraction" to describe the geometrical fraction of the X-ray emitting area covered by the ionized absorbers in the line of sight. The intrinsic X-ray luminosity is hardly variable in this model. We have applied the VPC model to the 27 Seyfert galaxies observed with Suzaku, and found that spectral variations of the 22 sources are successfully explained by this model only varying the partial covering fraction. Intrinsic X-ray luminosities of Seyfert galaxies are not variable, as opposed to what they apparently seem, and gravitationally red-shifted iron line is not necessary. Those ionized absorbing clouds are most likely to be Broad Line Region (BLR) clouds, and we will be able to constrain the BLR structure from X-ray observations.

Within-country variation of salt intake assessed via urinary excretion in Japan: a multilevel analysis in all 47 prefectures.

PubMed

Uechi, Ken; Asakura, Keiko; Masayasu, Shizuko; Sasaki, Satoshi

2017-06-01

Salt intake in Japan remains high; therefore, exploring within-country variation in salt intake and its cause is an important step in the establishment of salt reduction strategies. However, no nationwide evaluation of this variation has been conducted by urinalysis. We aimed to clarify whether within-country variation in salt intake exists in Japan after adjusting for individual characteristics. Healthy men (n=1027) and women (n=1046) aged 20-69 years were recruited from all 47 prefectures of Japan. Twenty-four-hour sodium excretion was estimated using three spot urine samples collected on three nonconsecutive days. The study area was categorized into 12 regions defined by the National Health and Nutrition Survey Japan. Within-country variation in sodium excretion was estimated as a population (region)-level variance using a multilevel model with random intercepts, with adjustment for individual biological, socioeconomic and dietary characteristics. Estimated 24 h sodium excretion was 204.8 mmol per day in men and 155.7 mmol per day in women. Sodium excretion was high in the Northeastern region. However, population-level variance was extremely small after adjusting for individual characteristics (0.8 and 2% of overall variance in men and women, respectively) compared with individual-level variance (99.2 and 98% of overall variance in men and women, respectively). Among individual characteristics, greater body mass index, living with a spouse and high miso-soup intake were associated with high sodium excretion in both sexes. Within-country variation in salt intake in Japan was extremely small compared with individual-level variation. Salt reduction strategies for Japan should be comprehensive and should not address the small within-country differences in intake.

Hawk Eyes I: Diurnal Raptors Differ in Visual Fields and Degree of Eye Movement

PubMed Central

O'Rourke, Colleen T.; Hall, Margaret I.; Pitlik, Todd; Fernández-Juricic, Esteban

2010-01-01

Background Different strategies to search and detect prey may place specific demands on sensory modalities. We studied visual field configuration, degree of eye movement, and orbit orientation in three diurnal raptors belonging to the Accipitridae and Falconidae families. Methodology/Principal Findings We used an ophthalmoscopic reflex technique and an integrated 3D digitizer system. We found inter-specific variation in visual field configuration and degree of eye movement, but not in orbit orientation. Red-tailed Hawks have relatively small binocular areas (∼33°) and wide blind areas (∼82°), but intermediate degree of eye movement (∼5°), which underscores the importance of lateral vision rather than binocular vision to scan for distant prey in open areas. Cooper's Hawks' have relatively wide binocular fields (∼36°), small blind areas (∼60°), and high degree of eye movement (∼8°), which may increase visual coverage and enhance prey detection in closed habitats. Additionally, we found that Cooper's Hawks can visually inspect the items held in the tip of the bill, which may facilitate food handling. American Kestrels have intermediate-sized binocular and lateral areas that may be used in prey detection at different distances through stereopsis and motion parallax; whereas the low degree eye movement (∼1°) may help stabilize the image when hovering above prey before an attack. Conclusions We conclude that: (a) there are between-species differences in visual field configuration in these diurnal raptors; (b) these differences are consistent with prey searching strategies and degree of visual obstruction in the environment (e.g., open and closed habitats); (c) variations in the degree of eye movement between species appear associated with foraging strategies; and (d) the size of the binocular and blind areas in hawks can vary substantially due to eye movements. Inter-specific variation in visual fields and eye movements can influence behavioral strategies to visually search for and track prey while perching. PMID:20877645

Hawk eyes I: diurnal raptors differ in visual fields and degree of eye movement.

PubMed

O'Rourke, Colleen T; Hall, Margaret I; Pitlik, Todd; Fernández-Juricic, Esteban

2010-09-22

Different strategies to search and detect prey may place specific demands on sensory modalities. We studied visual field configuration, degree of eye movement, and orbit orientation in three diurnal raptors belonging to the Accipitridae and Falconidae families. We used an ophthalmoscopic reflex technique and an integrated 3D digitizer system. We found inter-specific variation in visual field configuration and degree of eye movement, but not in orbit orientation. Red-tailed Hawks have relatively small binocular areas (∼33°) and wide blind areas (∼82°), but intermediate degree of eye movement (∼5°), which underscores the importance of lateral vision rather than binocular vision to scan for distant prey in open areas. Cooper's Hawks' have relatively wide binocular fields (∼36°), small blind areas (∼60°), and high degree of eye movement (∼8°), which may increase visual coverage and enhance prey detection in closed habitats. Additionally, we found that Cooper's Hawks can visually inspect the items held in the tip of the bill, which may facilitate food handling. American Kestrels have intermediate-sized binocular and lateral areas that may be used in prey detection at different distances through stereopsis and motion parallax; whereas the low degree eye movement (∼1°) may help stabilize the image when hovering above prey before an attack. We conclude that: (a) there are between-species differences in visual field configuration in these diurnal raptors; (b) these differences are consistent with prey searching strategies and degree of visual obstruction in the environment (e.g., open and closed habitats); (c) variations in the degree of eye movement between species appear associated with foraging strategies; and (d) the size of the binocular and blind areas in hawks can vary substantially due to eye movements. Inter-specific variation in visual fields and eye movements can influence behavioral strategies to visually search for and track prey while perching.

Mapping child maltreatment risk: a 12-year spatio-temporal analysis of neighborhood influences.

PubMed

Gracia, Enrique; López-Quílez, Antonio; Marco, Miriam; Lila, Marisol

2017-10-18

'Place' matters in understanding prevalence variations and inequalities in child maltreatment risk. However, most studies examining ecological variations in child maltreatment risk fail to take into account the implications of the spatial and temporal dimensions of neighborhoods. In this study, we conduct a high-resolution small-area study to analyze the influence of neighborhood characteristics on the spatio-temporal epidemiology of child maltreatment risk. We conducted a 12-year (2004-2015) small-area Bayesian spatio-temporal epidemiological study with all families with child maltreatment protection measures in the city of Valencia, Spain. As neighborhood units, we used 552 census block groups. Cases were geocoded using the family address. Neighborhood-level characteristics analyzed included three indicators of neighborhood disadvantage-neighborhood economic status, neighborhood education level, and levels of policing activity-, immigrant concentration, and residential instability. Bayesian spatio-temporal modelling and disease mapping methods were used to provide area-specific risk estimations. Results from a spatio-temporal autoregressive model showed that neighborhoods with low levels of economic and educational status, with high levels of policing activity, and high immigrant concentration had higher levels of substantiated child maltreatment risk. Disease mapping methods were used to analyze areas of excess risk. Results showed chronic spatial patterns of high child maltreatment risk during the years analyzed, as well as stability over time in areas of low risk. Areas with increased or decreased child maltreatment risk over the years were also observed. A spatio-temporal epidemiological approach to study the geographical patterns, trends over time, and the contextual determinants of child maltreatment risk can provide a useful method to inform policy and action. This method can offer a more accurate description of the problem, and help to inform more localized prevention and intervention strategies. This new approach can also contribute to an improved epidemiological surveillance system to detect ecological variations in risk, and to assess the effectiveness of the initiatives to reduce this risk.

Comparison of the petrography, palynology, and paleobotany of the Little Fire Creek coal bed, southwestern Virginia, USA

USGS Publications Warehouse

Pierce, B.S.; Eble, C.F.; Stanton, R.W.

1995-01-01

The proximate, petrographic, palynologic, and plant tissue data from two sets of samples indicate a high ash, gelocollinite- and liptinite-rich coal consisting of a relatively diverse paleoflora, including lycopsid trees, small lycopsids, tree ferns, small ferns, pteridosperms, and rare calamites and cordaites. The relatively very high ash yields the relatively thin subunits and the large scale vertical variations in palynomorph floras suggest that the study area was at the edge of the paleopeat-forming environment. -from Authors

Nature and nurture in the family physician's choice of practice location.

PubMed

Orzanco, Maria Gabriela; Lovato, Chris; Bates, Joanna; Slade, Steve; Grand'Maison, Paul; Vanasse, Alain

2011-01-01

An understanding of the contextual, professional, and personal factors that affect choice of practice location for physicians is needed to support successful strategies in addressing geographic maldistribution of physicians. This study compared two categories of predictors of family practice location in non-metropolitan areas among undergraduate medical students: individual characteristics (nature), and the rural program component of their training program (nurture). The study aimed to identify factors that predict the location of practice 2 years post-residency training and determine the predictive value of combining nature and nurture variables using administrative data from two undergraduate medical education programs. Databases were developed from available administrative sources for a retrospective analysis of two undergraduate medical education programs in Canada: Université de Sherbrooke (UdeS) and University of British Columbia (UBC). Both schools have a strong mandate to evaluate the impact of their programs on physician distribution. The dependent variable was location of practice 2 years after completing postgraduate training in family medicine. Independent variables included individual and program characteristics. Separate analyses were conducted for each program using multiple logistic regression. The nature and nurture variables considered in the models explained only 21% to 27% of the variance in the eventual location of practice of family physician graduates. For UdeS, having an address in a rural/small-town environment at application to medical school (OR=2.61, 95% CI: 1.24-6.06) and for UBC, location of high school in a rural/small town (OR=4.03, 95% CI: 1.05-15.41), both increased the chances of practicing in a non-metropolitan area. For UdeS the nurture variable (ie length of clerkship in a non-metropolitan area) was the most significant predictor (OR=1.14, 95% CI: 1.067-1.22). For both medical schools, adding a single nurture variable to the model using only nature variables significantly increased the amount of variation accounted for in predicting location of practice in non-metropolitan areas. Aspects of graduates' rural background increase the chances of practicing in a non-metropolitan area. A third-year clerkship experience in a rural area may increase the chances of non-metropolitan practice. Although the total variation predicted by both nature and nurture variables in this study was small, adding a nurture variable significantly improves the prediction of individuals who will practice in a non-metropolitan area. The fact that total variation predicted was small is likely to be due to the limitations of the administrative databases used. Different strategies are being implemented in each university to improve the quality of existing administrative databases, as well as to collect relevant data about intent-to-practice, training characteristics, and the attitudes, beliefs and backgrounds of students.

Why are most aquatic plants widely distributed? Dispersal, clonal growth and small-scale heterogeneity in a stressful environment

NASA Astrophysics Data System (ADS)

Santamaría, Luis

2002-06-01

Non-marine aquatic vascular plants generally show broad distributional ranges. Climatic factors seem to have limited effects on their distributions, besides the determination of major disjunctions (tropical-temperate-subarctic). Dispersal should have been frequent enough to assure the quick colonisation of extensive areas following glacial retreat, but dispersal limitation is still apparent in areas separated by geographic barriers. Aquatic vascular plants also show limited taxonomic differentiation and low within-species genetic variation. Variation within populations is particularly low, but variation among populations seems to be relatively high, mainly due to the persistence of long-lived clones. Ecotypic differentiation is often related to factors that constrain clonal reproduction (salinity and ephemeral inundation). Inland aquatic habitats are heterogeneous environments, but this heterogeneity largely occurs at relatively small scales (within waterbodies and among neighbouring ones). They also represent a stressful environment for plants, characterised by low carbon availability, shaded conditions, sediment anoxia, mechanical damage by currents and waves, significant restrictions to sexual reproduction, and sometimes also osmotic stress and limited nutrient supply. I propose that the generality of broad distributions and low differentiation among the inland aquatic flora is best explained by a combination of: (1) selection for stress-tolerant taxa with broad tolerance ranges. (2) The selective advantages provided by clonal growth and multiplication, which increases plant tolerance to stress, genet survivorship and population viability. (3) Long-distance dispersal of sexual propagules and high local dispersal of asexual clones. (4) The generality of broad plastic responses, promoted by the combination of clonal growth, high local dispersal, small-scale spatial heterogeneity and temporal variability.

Spatio-temporal Variations in Slow Earthquakes along the Mexican Subduction Zone

NASA Astrophysics Data System (ADS)

Ide, S.; Maury, J.; Cruz-Atienza, V. M.; Kostoglodov, V.

2017-12-01

Slow earthquakes in Mexico have been investigated independently in different areas. Here, we review differences in tremor behavior and slow slip events along the entire subduction zone to improve our understanding of its segmentation. Some similarities are observed between the Guerrero and Oaxaca areas. By combining our improved tremor detection capabilities with previous results, we suggest that there is no gap in tremor between Guerrero and Oaxaca. However some differences between Michoacan and Guerrero are seen (e.g., SSE magnitude, tremor zone width, tremor rate), suggesting that these two areas behave differently. Tremor initiation shows clear tidal sensitivity along the entire subduction zone. Tremor in Guerrero is sensitive to small tidal normal stress as well as shear stress suggesting the subduction plane may include local variations in dip. Estimation of the energy rate shows similar values along the subduction zone interface. The scaled tremor energy estimates are similar to those calculated in Nankai and Cascadia, suggesting a common mechanism. Along-strike differences in slow deformation may be related to variations in the subduction interface that yield different geometrical and temperature profiles.

Spatiotemporal Variations in Slow Earthquakes Along the Mexican Subduction Zone

NASA Astrophysics Data System (ADS)

Maury, J.; Ide, S.; Cruz-Atienza, V. M.; Kostoglodov, V.

2018-02-01

Slow earthquakes in Mexico have been investigated independently in different areas. Here we review differences in tremor behavior and slow slip events along the entire subduction zone to improve our understanding of its segmentation. Some similarities are observed between the Guerrero and Oaxaca areas. By combining our improved tremor detection capabilities with previous results, we suggest that there is no gap in tremor between Guerrero and Oaxaca. However, some differences between Michoacan and Guerrero are seen (e.g., SSE magnitude, tremor zone width, and tremor rate), suggesting that these two areas behave differently. Tremor initiation shows clear tidal sensitivity along the entire subduction zone. Tremor in Guerrero is sensitive to small tidal normal stress as well as shear stress, suggesting that the subduction plane may include local variations in dip. Estimation of the energy rate shows similar values along the subduction zone interface. The scaled tremor energy estimates are similar to those calculated in Nankai and Cascadia, suggesting a common mechanism. Along-strike differences in slow deformation may be related to variations in the subduction interface that yield different geometrical and temperature profiles.

Sidereal variations deep underground in Tasmania

NASA Technical Reports Server (NTRS)

Humble, J. E.; Fenton, A. G.; Fenton, K. B.

1985-01-01

Data from the deep underground vertically directed muon telescopes at Poatina, Tasmania, have been used since 1972 for a number of investigations, including the daily intensity variations, atmospheric influences, and checking for possible effects due to the interplanetary magnetic field. These telescopes have a total sensitive area of only 3 square meters, with the result that the counting rate is low (about 1680 events per hour) and the statistical errors on the results are rather large. Consequently, it was decided several years ago to construct larger detectors for this station. The first of these telescopes has been in operation for two complete years, and the results from it are presented. Results from the new, more stable equipment at Poatina appear to confirm the existence of a first harmonic in the daily variations in sidereal time reported earlier, and are consistent with small or non-existent first harmonics in solar and anti-sidereal time. All the second harmonics appear to be small, if not zero at these energies.

Seismic imaging of Q structures by a trans-dimensional coda-wave analysis

NASA Astrophysics Data System (ADS)

Takahashi, Tsutomu

2017-04-01

Wave scattering and intrinsic attenuation are important processes to describe incoherent and complex wave trains of high frequency seismic wave (>1Hz). The multiple lapse time window analysis (MLTWA) has been used to estimate scattering and intrinsic Q values by assuming constant Q in a study area (e.g., Hoshiba 1993). This study generalizes this MLTWA to estimate lateral variations of Q values under the Bayesian framework in dimension variable space. Study area is partitioned into small areas by means of the Voronoi tessellation. Scattering and intrinsic Q in each small area are constant. We define a misfit function for spatiotemporal variations of wave energy as with the original MLTWA, and maximize the posterior probability with changing not only Q values but the number and spatial layout of the Voronoi cells. This maximization is conducted by means of the reversible jump Markov chain Monte Carlo (rjMCMC) (Green 1995) since the number of unknown parameters (i.e., dimension of posterior probability) is variable. After a convergence to the maximum posterior, we estimate Q structures from the ensemble averages of MCMC samples around the maximum posterior probability. Synthetic tests showed stable reconstructions of input structures with reasonable error distributions. We applied this method for seismic waveform data recorded by ocean bottom seismograms at the outer-rise area off Tohoku, and estimated Q values at 4-8Hz, 8-16Hz and 16-32Hz. Intrinsic Q are nearly constant at all frequency bands, and scattering Q shows two distinct strong scattering regions at petit spot area and high seismicity area. These strong scattering are probably related to magma inclusions and fractured structure, respectively. Difference between these two areas becomes clear at high frequencies. It means that scale dependences of inhomogeneities or smaller scale inhomogeneity is important to discuss medium property and origins of structural variations. While the generalized MLTWA is based on a classical waveform modeling in constant Q medium, this method can be a fundamental basis for Q structure imaging in the crust.

Interpretation of Variations in Modis-Measured Greenness Levels of Amazon Forests During 2000 to 2009

NASA Technical Reports Server (NTRS)

Samanta, Arindam; Ganguly, Sangram; Vermote, Eric; Nemani, Ramakrishna R.; Myneni, Ranga B.

2012-01-01

This work investigates variations in satellite-measured greenness of Amazon forests using ten years of NASA Moderate Resolution Imaging Spectroradiometer (MODIS) enhanced vegetation index (EVI) data. Corruption of optical remote sensing data with clouds and aerosols is prevalent in this region; filtering corrupted data causes spatial sampling constraints, as well as reducing the record length, which introduces large biases in estimates of greenness anomalies. The EVI data, analyzed in multiple ways and taking into account EVI accuracy, consistently show a pattern of negligible changes in the greenness levels of forests both in the area affected by drought in 2005 and outside it. Small random patches of anomalous greening and browning-especially prominent in 2009-appear in all ten years, irrespective of contemporaneous variations in precipitation, but with no persistence over time. The fact that over 90% of the EVI anomalies are insignificantly small-within the envelope of error (95% confidence interval) in EVI-warrants cautious interpretation of these results: there were no changes in the greenness of these forests, or if there were changes, the EVI data failed to capture these either because the constituent reflectances were saturated or the moderate resolution precluded viewing small-scale variations. This suggests a need for more accurate and spatially resolved synoptic views from satellite data and corroborating comprehensive ground sampling to understand the greenness dynamics of these forests.

TIME DISTRIBUTIONS OF LARGE AND SMALL SUNSPOT GROUPS OVER FOUR SOLAR CYCLES

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

Kilcik, A.; Yurchyshyn, V. B.; Abramenko, V.

2011-04-10

Here we analyze solar activity by focusing on time variations of the number of sunspot groups (SGs) as a function of their modified Zurich class. We analyzed data for solar cycles 20-23 by using Rome (cycles 20 and 21) and Learmonth Solar Observatory (cycles 22 and 23) SG numbers. All SGs recorded during these time intervals were separated into two groups. The first group includes small SGs (A, B, C, H, and J classes by Zurich classification), and the second group consists of large SGs (D, E, F, and G classes). We then calculated small and large SG numbers frommore » their daily mean numbers as observed on the solar disk during a given month. We report that the time variations of small and large SG numbers are asymmetric except for solar cycle 22. In general, large SG numbers appear to reach their maximum in the middle of the solar cycle (phases 0.45-0.5), while the international sunspot numbers and the small SG numbers generally peak much earlier (solar cycle phases 0.29-0.35). Moreover, the 10.7 cm solar radio flux, the facular area, and the maximum coronal mass ejection speed show better agreement with the large SG numbers than they do with the small SG numbers. Our results suggest that the large SG numbers are more likely to shed light on solar activity and its geophysical implications. Our findings may also influence our understanding of long-term variations of the total solar irradiance, which is thought to be an important factor in the Sun-Earth climate relationship.« less

Monitoring Structure and Regional-Level Displacements for Lisbon Using Mltitemporal InSAR Techniques

NASA Astrophysics Data System (ADS)

Roque, Dora; Perissin, Daniele Falcao, Ana Paula; Fonseca, Ana Maria; Henriques, Maria Joao

2015-05-01

The city of Lisbon is the capital of Portugal and has been devastated by catastrophic events in the past, such as earthquakes and tsunamis. This study provides a regional analysis of displacements for the city and its neighbourhoods, between 2008 and 2010, through the application of mutitemporal InSAR techniques on Envisat ASAR images. Smaller areas with identified problems were subjected to a more refined processing. Besides, the behaviour of some key infrastructures, such as important buildings or railways, was carefully analysed in order to evaluate their safety. Subsidence was detected at the regional and small areas, in which the highest subsidence rates were verified on industrial parks or on landfills close to the river. Seasonal trends were found for the small areas, mainly related with structure thermal expansion or variations in underground water.

Temporal Variations of Different Solar Activity Indices Through the Solar Cycles 21-23

NASA Astrophysics Data System (ADS)

Göker, Ü. D.; Singh, J.; Nutku, F.; Priyal, M.

2017-12-01

Here, we compare the sunspot counts and the number of sunspot groups (SGs) with variations of total solar irradiance (TSI), magnetic activity, Ca II K-flux, faculae and plage areas. We applied a time series method for extracting the data over the descending phases of solar activity cycles (SACs) 21, 22 and 23, and the ascending phases 22 and 23. Our results suggest that there is a strong correlation between solar activity indices and the changes in small (A, B, C and H-modified Zurich Classification) and large (D, E and F) SGs. This somewhat unexpected finding suggests that plage regions substantially decreased in spite of the higher number of large SGs in SAC 23 while the Ca II K-flux did not decrease by a large amount nor was it comparable with SAC 22 and relates with C and DEF type SGs. In addition to this, the increase of facular areas which are influenced by large SGs, caused a small percentage decrease in TSI while the decrement of plage areas triggered a higher decrease in the magnetic field flux. Our results thus reveal the potential of such a detailed comparison of the SG analysis with solar activity indices for better understanding and predicting future trends in the SACs.

Cloud and convection frequencies over the southeast United States as related to small-scale geographic features

NASA Technical Reports Server (NTRS)

Gibson, Harold M.; Vonder Haar, Thomas H.

1990-01-01

Based on relatively high spatial and temporal resolution satelite data collected at 0700 CST and at each hour from 1000 CST to 1700 CST during the summer of 1986, cloud and convection variations over the area from Mississippi east to Georgia and from the Gulf of Mexico north to Tennessee are discussed. The data analyses show an average maximum cloud frequency over the land areas at 1400 local time and a maximum of deep convection one hour later. Both cloudiness and deep convection are found to be at a maximum during the nocturnal hours over the Gulf of Mexico. Cloud frequency shows a strong relationship to small terrain features. Small fresh water bodies have cloud minima relative to the surroundings in the afternoon hours. Higher, steep terrain shows cloud maxima and the adjacent lower terrain exhibits afternoon cloud minima due to a divergence of mountain breeze caused by the valley.

Social exclusion, deprivation and child health: a spatial analysis of ambulatory care sensitive conditions in children aged 0-4 years in Victoria, Australia.

PubMed

Butler, Danielle C; Thurecht, Linc; Brown, Laurie; Konings, Paul

2013-10-01

Recent Australian policy initiatives regarding primary health care focus on planning services around community needs and delivering these at the local area. As in many other countries, there has also been a growing concern over social inequities in health outcomes. The aims of the analysis presented here were firstly to describe small area variations in hospital admissions for ambulatory care sensitive conditions (ACSC) among children aged 0-4 years between 2003 and 2009 in the state of Victoria, Australia, and secondly to explore the relationship of ACSC hospitalisations with socio-economic disadvantage using a comparative analysis of the Child Social Exclusion (CSE) index and the Composite Score of Deprivation (CSD). This is a cross sectional secondary data analysis, with data sourced from 2003 to 2009 ACSC data from the Victorian State Government Department of Health; the Australian Standard Geographical Classification of remoteness; the Australian 2006 Census of Population and Housing; and AMPCo General Practitioner data from 2010. The relationship between the indexes and child health outcomes was examined through bivariate analysis and visually through a series of maps. The results show there is significant variation in the geographical distribution of the relationship between ACSCs and socio-economic disadvantage, with both indexes capturing important social gradients in child health conditions. However, measures of access, such as geographical accessibility and workforce supply, detect additional small area variation in child health outcomes. This research has important implications for future primary health care policy and planning of services, as these findings confirm that not all areas are the same in terms of health outcomes, and there may be benefit in tailoring mechanisms for identifying areas of need depending on the outcome intended to be affected. Copyright © 2013 Elsevier Ltd. All rights reserved.

Transitions

NASA Technical Reports Server (NTRS)

2006-01-01

26 May 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a variety of textures observed on a dust-covered plain in the Marte Valles region of Mars. Textural variations across the scene include: areas that are littered with small impact craters, a channel-like feature that is dominated by mounds of a variety of sizes, small ripples and/or ridges, and relatively smooth, unremarkable terrain. The contact between the cratered plain and the area dominated by mounds marks one of the banks along the edge of one of the shallow valleys of the Marte Valles system.

Location near: 17.7oN, 175.0oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Spring

Feral Cats Are Better Killers in Open Habitats, Revealed by Animal-Borne Video

PubMed Central

McGregor, Hugh; Legge, Sarah; Jones, Menna E.; Johnson, Christopher N.

2015-01-01

One of the key gaps in understanding the impacts of predation by small mammalian predators on prey is how habitat structure affects the hunting success of small predators, such as feral cats. These effects are poorly understood due to the difficulty of observing actual hunting behaviours. We attached collar-mounted video cameras to feral cats living in a tropical savanna environment in northern Australia, and measured variation in hunting success among different microhabitats (open areas, dense grass and complex rocks). From 89 hours of footage, we recorded 101 hunting events, of which 32 were successful. Of these kills, 28% were not eaten. Hunting success was highly dependent on microhabitat structure surrounding prey, increasing from 17% in habitats with dense grass or complex rocks to 70% in open areas. This research shows that habitat structure has a profound influence on the impacts of small predators on their prey. This has broad implications for management of vegetation and disturbance processes (like fire and grazing) in areas where feral cats threaten native fauna. Maintaining complex vegetation cover can reduce predation rates of small prey species from feral cat predation. PMID:26288224

Response Variability in Commercial MOSFET SEE Qualification

DOE PAGES

George, J. S.; Clymer, D. A.; Turflinger, T. L.; ...

2016-12-01

Single-event effects (SEE) evaluation of five different part types of next generation, commercial trench MOSFETs indicates large part-to-part variation in determining a safe operating area (SOA) for drain-source voltage (V DS) following a test campaign that exposed >50 samples per part type to heavy ions. These results suggest a determination of a SOA using small sample sizes may fail to capture the full extent of the part-to-part variability. An example method is discussed for establishing a Safe Operating Area using a one-sided statistical tolerance limit based on the number of test samples. Finally, burn-in is shown to be a criticalmore » factor in reducing part-to-part variation in part response. Implications for radiation qualification requirements are also explored.« less

Response Variability in Commercial MOSFET SEE Qualification

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

George, J. S.; Clymer, D. A.; Turflinger, T. L.

Single-event effects (SEE) evaluation of five different part types of next generation, commercial trench MOSFETs indicates large part-to-part variation in determining a safe operating area (SOA) for drain-source voltage (V DS) following a test campaign that exposed >50 samples per part type to heavy ions. These results suggest a determination of a SOA using small sample sizes may fail to capture the full extent of the part-to-part variability. An example method is discussed for establishing a Safe Operating Area using a one-sided statistical tolerance limit based on the number of test samples. Finally, burn-in is shown to be a criticalmore » factor in reducing part-to-part variation in part response. Implications for radiation qualification requirements are also explored.« less

Disadvantaged but Different: Variation among Deprived Communities in Relation to Child and Family Well-Being

ERIC Educational Resources Information Center

Barnes, Jacqueline; Belsky, Jay; Broomfield, Kate A.; Dave, Sapna; Frost, Martin; Melhuish, Edward

2005-01-01

Background: Disadvantaged communities are increasingly the target for interventions. Sure Start was launched in England in 1999 to tackle child poverty and improve child and family services, with Sure Start Local Programmes (SSLPs) targeted at relatively small areas of marked deprivation. However, they are located in a range of different types of…

Spatial heterogeneity and temporal variations in Echinococcus multilocularis infections in wild hosts in a North American urban setting.

PubMed

Liccioli, Stefano; Kutz, Susan J; Ruckstuhl, Kathreen E; Massolo, Alessandro

2014-06-01

Echinococcus multilocularis, the causative agent of human alveolar echinococcosis, has the potential to circulate in urban areas where wild host populations and humans coexist. The spatial and temporal distribution of infection in wild hosts locally affects the risk of transmission to humans. We investigated the spatial and temporal patterns of E. multilocularis infection in coyotes and rodent intermediate hosts within the city of Calgary, Canada, and the association between spatial variations in coyote infection and the relative composition of small mammal assemblages. Infection by E. multilocularis was examined in small mammals and coyote faeces collected monthly in five city parks from June 2012 to June 2013. Coyote faeces were analysed using a ZnCl(2) centrifugation and sedimentation protocol. Infection in intermediate hosts was assessed through lethal trapping and post-mortem analysis. Parasite eggs and metacestodes were morphologically identified and molecularly confirmed through species-specific PCR assays. Of 982 small mammals captured, infection was detected in 2/305 (0.66%) deer mice (Peromyscus maniculatus), 2/267 (0.75%) meadow voles (Microtus pennsylvanicus), and 1/71 (1.41%) southern red backed voles (Myodes gapperi). Overall faecal prevalence in coyotes was 21.42% (n = 385) and varied across sites, ranging from 5.34% to 61.48%. Differences in coyote faecal prevalence across sites were consistent with local variations in the relative abundance of intermediate hosts within the small mammal assemblages. Infections peaked in intermediate hosts during autumn (0.68%) and winter (3.33%), and in coyotes during spring (43.47%). Peaks of infections in coyote faeces up to 83.8% in autumn were detected in a hyper-endemic area. To the best of our knowledge, our findings represent the first evidence of a sylvatic life-cycle of E. multilocularis in a North American urban setting, and provide new insights into the complexity of the parasite transmission ecology. Copyright © 2014 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Geographic variation and effect of area-level poverty rate on colorectal cancer screening.

PubMed

Lian, Min; Schootman, Mario; Yun, Shumei

2008-10-16

With a secular trend of increasing colorectal cancer (CRC) screening, concerns about disparities in CRC screening also have been rising. It is unclear if CRC screening varies geographically, if area-level poverty rate affects CRC screening, and if individual-level characteristics mediate the area-level effects on CRC screening. Using 2006 Missouri Behavioral Risk Factor Surveillance System (BRFSS) data, a multilevel study was conducted to examine geographic variation and the effect of area-level poverty rate on CRC screening use among persons age 50 or older. Individuals were nested within ZIP codes (ZIP5 areas), which in turn, were nested within aggregations of ZIP codes (ZIP3 areas). Six groups of individual-level covariates were considered as potential mediators. An estimated 51.8% of Missourians aged 50 or older adhered to CRC screening recommendations. Nearly 15% of the total variation in CRC screening lay between ZIP5 areas. Persons residing in ZIP5 areas with > or = 10% of poverty rate had lower odds of CRC screening use than those residing in ZIP5 areas with <10% poverty rate (unadjusted odds ratio [OR], 0.69; 95% confidence interval [95% CI], 0.58-0.81; adjusted OR, 0.81; 95% CI, 0.67-0.98). Persons who resided in ZIP3 areas with > or = 20% poverty rate also had lower odds of following CRC screening guidelines than those residing in ZIP3 areas with <20% poverty rate (unadjusted OR, 0.66; 95% CI, 0.52-0.83; adjusted OR, 0.64; 95% CI, 0.50-0.83). Obesity, history of depression/anxiety and access to care were associated with CRC screening, but did not mediate the effect of area-level poverty on CRC screening. Large geographic variation of CRC screening exists in Missouri. Area-level poverty rate, independent of individual-level characteristics, is a significant predictor of CRC screening, but it only explains a small portion of the geographic heterogeneity of CRC screening. Individual-level factors we examined do not mediate the effect of the area-level poverty rate on CRC screening. Future studies should identify other area- and individual-level characteristics associated with CRC screening in Missouri.

Analysis of Darwin Rainfall Data: Implications on Sampling Strategy

NASA Technical Reports Server (NTRS)

Rafael, Qihang Li; Bras, Rafael L.; Veneziano, Daniele

1996-01-01

Rainfall data collected by radar in the vicinity of Darwin, Australia, have been analyzed in terms of their mean, variance, autocorrelation of area-averaged rain rate, and diurnal variation. It is found that, when compared with the well-studied GATE (Global Atmospheric Research Program Atlantic Tropical Experiment) data, Darwin rainfall has larger coefficient of variation (CV), faster reduction of CV with increasing area size, weaker temporal correlation, and a strong diurnal cycle and intermittence. The coefficient of variation for Darwin rainfall has larger magnitude and exhibits larger spatial variability over the sea portion than over the land portion within the area of radar coverage. Stationary, and nonstationary models have been used to study the sampling errors associated with space-based rainfall measurement. The nonstationary model shows that the sampling error is sensitive to the starting sampling time for some sampling frequencies, due to the diurnal cycle of rain, but not for others. Sampling experiments using data also show such sensitivity. When the errors are averaged over starting time, the results of the experiments and the stationary and nonstationary models match each other very closely. In the small areas for which data are available for I>oth Darwin and GATE, the sampling error is expected to be larger for Darwin due to its larger CV.

Subglacial drainage effects on surface motion on a small surge type alpine glacier on the St. Elias range, Yukon Territory, Canada.

NASA Astrophysics Data System (ADS)

Rada, C.; Schoof, C.; King, M. A.; Flowers, G. E.; Haber, E.

2017-12-01

Subglacial drainage is known to play an important role in glacier dynamics trough its influence on basal sliding. However, drainage is also one of the most poorly understood process in glacier flow due to the difficulties of observing, identifying and modeling the physics involved. In an effort to improve understanding of subglacial processes, we have monitored a small, approximately 100 m thick surge-type alpine glacier for nine years. Over 300 boreholes were instrumented with pressure transducers over a 0.5 km² in its upper ablation area, in addition to a weather station and a permanent GPS array consisting on 16 dual-frequency receivers within the study area. We study the influence of the subglacial drainage system on the glacier surface velocity. However, pressure variations in the drainage system during the melt season are dominated by diurnal oscillations.Therefore, GPS solutions have to be computed at sub-diurnal time intervals in order to explore the effects of transient diurnal pressure variations. Due to the small displacements of the surface of the glacier over those periods (4-10 cm/day), sub-diurnal solutions are dominated by errors, making it impossible to observe the diurnal variations in glacier motion. We have found that the main source of error is GPS multipath. This error source does largely cancel out when solutions are computed over 24 hour periods (or more precisely, over a sidereal day), but solution precisions decrease quickly when computed over shorter periods of time. Here we present an inverse problem approach to remove GPS multipath errors on glaciers, and use the reconstructed glacier motion to explore how the subglacial drainage morphology and effective pressure influence glacier dynamics at multiple time scales.

Spatial distribution of soil organic carbon and total nitrogen based on GIS and geostatistics in a small watershed in a hilly area of northern China.

PubMed

Peng, Gao; Bing, Wang; Guangpo, Geng; Guangcan, Zhang

2013-01-01

The spatial variability of soil organic carbon (SOC) and total nitrogen (STN) levels is important in both global carbon-nitrogen cycle and climate change research. There has been little research on the spatial distribution of SOC and STN at the watershed scale based on geographic information systems (GIS) and geostatistics. Ninety-seven soil samples taken at depths of 0-20 cm were collected during October 2010 and 2011 from the Matiyu small watershed (4.2 km(2)) of a hilly area in Shandong Province, northern China. The impacts of different land use types, elevation, vegetation coverage and other factors on SOC and STN spatial distributions were examined using GIS and a geostatistical method, regression-kriging. The results show that the concentration variations of SOC and STN in the Matiyu small watershed were moderate variation based on the mean, median, minimum and maximum, and the coefficients of variation (CV). Residual values of SOC and STN had moderate spatial autocorrelations, and the Nugget/Sill were 0.2% and 0.1%, respectively. Distribution maps of regression-kriging revealed that both SOC and STN concentrations in the Matiyu watershed decreased from southeast to northwest. This result was similar to the watershed DEM trend and significantly correlated with land use type, elevation and aspect. SOC and STN predictions with the regression-kriging method were more accurate than those obtained using ordinary kriging. This research indicates that geostatistical characteristics of SOC and STN concentrations in the watershed were closely related to both land-use type and spatial topographic structure and that regression-kriging is suitable for investigating the spatial distributions of SOC and STN in the complex topography of the watershed.

Spatial Distribution of Soil Organic Carbon and Total Nitrogen Based on GIS and Geostatistics in a Small Watershed in a Hilly Area of Northern China

PubMed Central

Peng, Gao; Bing, Wang; Guangpo, Geng; Guangcan, Zhang

2013-01-01

The spatial variability of soil organic carbon (SOC) and total nitrogen (STN) levels is important in both global carbon-nitrogen cycle and climate change research. There has been little research on the spatial distribution of SOC and STN at the watershed scale based on geographic information systems (GIS) and geostatistics. Ninety-seven soil samples taken at depths of 0–20 cm were collected during October 2010 and 2011 from the Matiyu small watershed (4.2 km2) of a hilly area in Shandong Province, northern China. The impacts of different land use types, elevation, vegetation coverage and other factors on SOC and STN spatial distributions were examined using GIS and a geostatistical method, regression-kriging. The results show that the concentration variations of SOC and STN in the Matiyu small watershed were moderate variation based on the mean, median, minimum and maximum, and the coefficients of variation (CV). Residual values of SOC and STN had moderate spatial autocorrelations, and the Nugget/Sill were 0.2% and 0.1%, respectively. Distribution maps of regression-kriging revealed that both SOC and STN concentrations in the Matiyu watershed decreased from southeast to northwest. This result was similar to the watershed DEM trend and significantly correlated with land use type, elevation and aspect. SOC and STN predictions with the regression-kriging method were more accurate than those obtained using ordinary kriging. This research indicates that geostatistical characteristics of SOC and STN concentrations in the watershed were closely related to both land-use type and spatial topographic structure and that regression-kriging is suitable for investigating the spatial distributions of SOC and STN in the complex topography of the watershed. PMID:24391791

Progress in the application of landform analysis in studies of semiarid erosion

USGS Publications Warehouse

Schumm, Stanley Alfred; Hadley, R.F.

1961-01-01

The analysis of topographic and hydrologic data gathered during studies of erosion in semiarid areas of Western United States show the following relation: (a) Mean annual sediment yield from small drainage basins is related to a ratio of basin relief to length; (b) mean annual runoff from small drainage basins is related to drainage density; (c) mean annual sediment yield per unit area decreases with increase in drainage area; (d) the form of some convex hill slopes is related to surficial creep; (e) asymmetry of drainage basins, including differences in hill-slope erosion and drainage density, is related to microclimatic variations on slopes of diverse exposure; .(f) the cutting of discontinuous gullies is closely related to steepening by deposition of the semiarid valley floor; (g) aggradation in ephemeral streams seems to be most prevalent in reaches where the ratio of contributing drainage area to channel length is relatively small; and (h) streamchannel shape, expressed as a width-depth ratio, is related to the percentage of silt-clay in bed and bank alluvium. The above relations cannot be detected without measurement of terrain characteristics. They further indicate the importance of quantitative terrain analysis in studies of erosion.

Seasonal and spatial variation of arsenic in groundwater in a rhyolithic volcanic area of Lesvos Island, Greece.

PubMed

Zkeri, Eirini; Aloupi, Maria; Gaganis, Petros

2017-12-23

A survey conducted in water wells located in the rhyolithic volcanic area of Mandamados, Lesvos Island, Greece, indicated that significant seasonal variation of arsenic concentration in groundwater exists mainly in wells near the coastal zone. However, there were differences among those coastal wells with regard to the processes and factors responsible for the observed seasonal variability of the element, although they are all located in a small homogeneous area. These processes and factors include (a) a higher rate of silicate weathering and ion exchange during the dry period followed by the dilution by the recharge water during the wet period, (b) enhanced desorption promoted by higher pH in summer and subsequent dilution of As by rainwater infiltration during the wet period, and (c) reductive dissolution of Mn during the wet period and by desorption under high pH values during the dry period. On the other hand, in wells located in higher-relief regions, the concentration of As in groundwater followed a fairly constant pattern throughout the year, which is probably related to the faster flow of groundwater in this part of the area due to a higher hydraulic gradient. In general, seasonal variation of As in groundwater in the study area was found to be related to geology, recharge rate, topography-distance from coast, and well depth.

Geographic variation in colorectal cancer survival and the role of small-area socioeconomic deprivation: a multilevel survival analysis of the NIH-AARP Diet and Health Study Cohort.

PubMed

Lian, Min; Schootman, Mario; Doubeni, Chyke A; Park, Yikyung; Major, Jacqueline M; Stone, Rosalie A Torres; Laiyemo, Adeyinka O; Hollenbeck, Albert R; Graubard, Barry I; Schatzkin, Arthur

2011-10-01

Adverse socioeconomic conditions, at both the individual and the neighborhood level, increase the risk of colorectal cancer (CRC) death, but little is known regarding whether CRC survival varies geographically and the extent to which area-level socioeconomic deprivation affects this geographic variation. Using data from the National Institutes of Health (NIH)-AARP Diet and Health Study, the authors examined geographic variation and the role of area-level socioeconomic deprivation in CRC survival. CRC cases (n = 7,024), identified during 1995-2003, were followed for their CRC-specific vital status through 2005 and overall vital status through 2006. Bayesian multilevel survival models showed that there was significant geographic variation in overall (variance = 0.2, 95% confidence interval (CI): 0.1, 0.2) and CRC-specific (variance = 0.3, 95% CI: 0.1, 0.4) risk of death. More socioeconomically deprived neighborhoods had a higher overall risk of death (most deprived quartile vs. least deprived: hazard ratio = 1.2, 95% CI: 1.1, 1.4) and a higher CRC-specific risk of death (most deprived quartile vs. least deprived: hazard ratio = 1.2, 95% CI: 1.1, 1.5). However, neighborhood socioeconomic deprivation did not account for the geographic variation in overall and CRC-specific risks of death. In future studies, investigators should evaluate other neighborhood characteristics to help explain geographic heterogeneity in CRC survival. Such research could facilitate interventions for reducing geographic disparity in CRC survival.

Slope variation and population structure of tree species from different ecological groups in South Brazil.

PubMed

Bianchini, Edmilson; Garcia, Cristina C; Pimenta, José A; Torezan, José M D

2010-09-01

Size structure and spatial arrangement of 13 abundant tree species were determined in a riparian forest fragment in Paraná State, South Brazil (23°16'S and 51°01'W). The studied species were Aspidosperma polyneuron Müll. Arg., Astronium graveolens Jacq. and Gallesia integrifolia (Spreng) Harms (emergent species); Alseis floribunda Schott, Ruprechtia laxiflora Meisn. and Bougainvillea spectabilis Willd. (shade-intolerant canopy species); Machaerium paraguariense Hassl, Myroxylum peruiferum L. and Chrysophyllum gonocarpum (Mart. & Eichler ex Miq.) Engl. (shade-tolerant canopy species); Sorocea bonplandii (Baill.) Bürger, Trichilia casaretti C. Dc, Trichilia catigua A. Juss. and Actinostemon concolor (Spreng.) Müll. Arg. (understory small trees species). Height and diameter structures and basal area of species were analyzed. Spatial patterns and slope correlation were analyzed by Moran's / spatial autocorrelation coefficient and partial Mantel test, respectively. The emergent and small understory species showed the highest and the lowest variations in height, diameter and basal area. Size distribution differed among emergent species and also among canopy shade-intolerant species. The spatial pattern ranged among species in all groups, except in understory small tree species. The slope was correlated with spatial pattern for A. polyneuron, A. graveolens, A. floribunda, R. laxiflora, M. peruiferum and T. casaretti. The results indicated that most species occurred in specific places, suggesting that niche differentiation can be an important factor in structuring the tree community.

Estimating diabetes prevalence by small area in England.

PubMed

Congdon, Peter

2006-03-01

Diabetes risk is linked to both deprivation and ethnicity, and so prevalence will vary considerably between areas. Prevalence differences may partly account for geographic variation in health performance indicators for diabetes, which are based on age standardized hospitalization or operation rates. A positive correlation between prevalence and health outcomes indicates that the latter are not measuring only performance. A regression analysis of prevalence rates according to age, sex and ethnicity from the Health Survey for England (HSE) is undertaken and used (together with census data) to estimate diabetes prevalence for 354 English local authorities and 8000 smaller areas (electoral wards). An adjustment for social factors is based on a prevalence gradient over area-deprivation quintiles. A Bayesian estimation approach is used allowing simple inclusion of evidence on prevalence from other or historical sources. The estimated prevalent population in England is 1.5 million (188 000 type 1 and 1.341 million type 2). At strategic health authority (StHA) level, prevalence varies from 2.4 (Thames Valley) to 4 per cent (North East London). The prevalence estimates are used to assess variations between local authorities in adverse hospitalization indicators for diabetics and to assess the relationship between diabetes-related mortality and prevalence. In particular, rates of diabetic ketoacidosis (DKA) and coma are positively correlated with prevalence, while diabetic amputation rates are not. The methodology developed is applicable to developing small-area-prevalence estimates for a range of chronic diseases, when health surveys assess prevalence by demographic categories. In the application to diabetes prevalence, there is evidence that performance indicators as currently calculated are not corrected for prevalence.

In-line verification of linewidth uniformity for 0.18 and below: design rule reticles

NASA Astrophysics Data System (ADS)

Tan, TaiSheng; Kuo, Shen C.; Wu, Clare; Falah, Reuven; Hemar, Shirley; Sade, Amikam; Gottlib, Gidon

2000-07-01

Mask making process development and control is addressed using a reticle inspection tool equipped with the new revolutionized application called LBM-Linewidth Bias Monitoring. In order to use the LBM for mask-making process control, procedures and corresponding test plates are a developed, such that routine monitoring of the manufacturing process discloses process variation and machine variation. At the same time systematic variation are studied and either taken care of or taken into consideration to allow successful production line work. In this paper the contribution of the LBM for mask quality monitoring is studied with respect to dense layers, e.g. DRAM. Another aspect of this application - the detection of very small CD mis-uniformity areas is discussed.

Area 4 has layer IV in adult primates

PubMed Central

García-Cabezas, Miguel Ángel; Barbas, Helen

2014-01-01

There are opposing views about the status of layer IV in primary motor cortex (area 4). Cajal described a layer IV in area 4 of adult humans. In contrast, Brodmann found layer IV in development but not in adult primates and called area 4 ‘agranular’. We addressed this issue in rhesus monkeys using the neural marker SMI-32, which labels neurons in lower layer III and upper V, but not in layer IV. SMI-32 delineated a central unlabeled cortical stripe in area 4 that corresponds to layer IV, which was populated with small interneurons also found in layer IV in ‘granular’ areas (such as area 46). We distinguished layer IV interneurons from projection neurons in the layers above and below using cellular criteria. The commonly used term ‘agranular’ for area 4 is also used for the phylogenetically ancient limbic cortices, confusing areas that differ markedly in laminar structure. This issue pertains to the systematic variation in the architecture across cortices, traced from limbic cortices through areas with increasingly more elaborate laminar structure. The principle of systematic variation can be used to predict laminar patterns of connections across cortical systems. This principle places area 4 and agranular anterior cingulate cortices at opposite poles of the graded laminar differentiation of motor cortices. The status of layer IV in area 4 thus pertains to core organizational features of the cortex, its connections and evolution. PMID:24735460

Sex-specific differences of craniofacial traits in Croatia: the impact of environment in a small geographic area.

PubMed

Buretic-Tomljanovic, Alena; Giacometti, Jasminka; Ostojic, Sasa; Kapovic, Miljenko

2007-01-01

Craniometric variation in humans reflects different genetic and environmental influences. Long-term climatic adaptation is less likely to show an impact on size and shape variation in a small local area than at the global level. The aim of this work was to assess the contribution of the particular environmental factors to body height and craniofacial variability in a small geographic area of Croatia. A total of 632 subjects, aged 18-21, participated in the survey. Body height, head length, head breadth, head height, head circumference, cephalic index, morphological face height, face breadth, and facial index were analysed regarding geographic, climatic and dietary conditions in different regions of the country, and correlated with the specific climatic variables (cumulative multiyear sunshine duration, cumulative multiyear average precipitation, multiyear average air temperatures) and calcium concentrations in drinking water. Significant differences between groups classified according to geographic, climatic or dietary affiliation, and the impact of the environmental predictors on the variation in the investigated traits were assessed using multiple forward stepwise regression analyses. Higher body height measures in both sexes were significantly correlated with Mediterranean diet type. Mediterranean diet type also contributed to higher head length and head circumference measures in females. Cephalic index values correlated to geographic regions in both sexes, showing an increase from southern to eastern Croatia. In the same direction, head length significantly decreased in males and head breadth increased in females. Mediterranean climate was associated with higher and narrower faces in females. The analysis of the particular climatic variables did not reveal a significant influence on body height in either sex. Concurrently, climatic features influenced all craniofacial traits in females and only head length and facial index in males. Mediterranean climate, characterized by higher average sunshine duration, higher average precipitation and higher average air temperatures, was associated with longer, higher and narrower skulls, higher head circumference, lower cephalic index, and higher and narrower faces (lower facial index). Calcium concentrations in drinking water did not correlate significantly with any dependent variable. A significant effect of environmental factors on body height and craniofacial variability was found in Croatian young adult population. This effect was more pronounced in females, revealing sex-specific craniofacial differentiation. However, the impact of environment was low and may explain only 1.0-7.32% variation of the investigated traits.

Spatial variation in diesel-related elemental and organic PM2.5 components during workweek hours across a downtown core.

PubMed

Tunno, Brett J; Shmool, Jessie L C; Michanowicz, Drew R; Tripathy, Sheila; Chubb, Lauren G; Kinnee, Ellen; Cambal, Leah; Roper, Courtney; Clougherty, Jane E

2016-12-15

Capturing intra-urban variation in diesel-related pollution exposures remains a challenge, given its complex chemical mix, and relatively few well-characterized ambient-air tracers for the multiple diesel sources in densely-populated urban areas. To capture fine-scale spatial resolution (50×50m grid cells) in diesel-related pollution, we used geographic information systems (GIS) to systematically allocate 36 sampling sites across downtown Pittsburgh, PA, USA (2.8km 2 ), cross-stratifying to disentangle source impacts (i.e., truck density, bus route frequency, total traffic density). For buses, outbound and inbound trips per week were summed by route and a kernel density was calculated across sites. Programmable monitors collected fine particulate matter (PM 2.5 ) samples specific to workweek hours (Monday-Friday, 7 am-7 pm), summer and winter 2013. Integrated filters were analyzed for black carbon (BC), elemental carbon (EC), organic carbon (OC), elemental constituents, and diesel-related organic compounds [i.e., polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes]. To our knowledge, no studies have collected this suite of pollutants with such high sampling density, with the ability to capture spatial patterns during specific hours of interest. We hypothesized that we would find substantial spatial variation for each pollutant and significant associations with key sources (e.g. diesel and gasoline vehicles), with higher concentrations near the center of this small downtown core. Using a forward stepwise approach, we developed seasonal land use regression (LUR) models for PM 2.5 , BC, total EC, OC, PAHs, hopanes, steranes, aluminum (Al), calcium (Ca), and iron (Fe). Within this small domain, greater concentration differences were observed in most pollutants across sites, on average, than between seasons. Higher PM 2.5 and BC concentrations were found in the downtown core compared to the boundaries. PAHs, hopanes, and steranes displayed different spatial patterning across the study area by constituent. Most LUR models suggested a strong influence of bus-related emissions on pollution gradients. Buses were more dominant predictors compared to truck and vehicular traffic for several pollutants. Overall, we found substantial variation in diesel-related concentrations in a very small downtown area, which varied across elemental and organic components. Copyright © 2016. Published by Elsevier B.V.

Influence of foraging behavior and host spatial distribution on the localized spread of the emerald ash borer, Agrilus planipennis

Treesearch

Rodrigo J. Mercader; Nathan W. Siegert; Andrew M. Liebhold; Deborah G. McCullough

2011-01-01

Management programs for invasive species are often developed at a regional or national level, but physical intervention generally takes place over relatively small areas occupied by newly founded, isolated populations. The ability to predict how local habitat variation affects the expansion of such newly founded populations is essential for efficiently targeting...

The micro-environmental impact of volatile organic compound emissions from large-scale assemblies of people in a confined space

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

Dutta, Tanushree

Large-scale assemblies of people in a confined space can exert significant impacts on the local air chemistry due to human emissions of volatile organics. Variations of air-quality in such small scale can be studied by quantifying fingerprint volatile organic compounds (VOCs) such as acetone, toluene, and isoprene produced during concerts, movie screenings, and sport events (like the Olympics and the World Cup). This review summarizes the extent of VOC accumulation resulting from a large population in a confined area or in a small open area during sporting and other recreational activities. Apart from VOCs emitted directly from human bodies (e.g.,more » perspiration and exhaled breath), those released indirectly from other related sources (e.g., smoking, waste disposal, discharge of food-waste, and use of personal-care products) are also discussed. Although direct and indirect emissions of VOCs from human may constitute <1% of the global atmospheric VOCs budget, unique spatiotemporal variations in VOCs species within a confined space can have unforeseen impacts on the local atmosphere to lead to acute human exposure to harmful pollutants.« less

Soil-geomorphic heterogeneity governs patchy vegetation dynamics at an arid ecotone.

PubMed

Bestelmeyer, Brandon T; Ward, Judy P; Havstad, Kris M

2006-04-01

Soil properties are well known to affect vegetation, but the role of soil heterogeneity in the patterning of vegetation dynamics is poorly documented. We asked whether the location of an ecotone separating grass-dominated and sparsely vegetated areas reflected only historical variation in degradation or was related to variation in inherent soil properties. We then asked whether changes in the cover and spatial organization of vegetated and bare patches assessed using repeat aerial photography reflected self-organizing dynamics unrelated to soil variation or the stable patterning of soil variation. We found that the present-day ecotone was related to a shift from more weakly to more strongly developed soils. Parts of the ecotone were stable over a 60-year period, but shifts between bare and vegetated states, as well as persistently vegetated and bare states, occurred largely in small (<40 m2) patches throughout the study area. The probability that patches were presently vegetated or bare, as well as the probability that vegetation persisted and/or established over the 60-year period, was negatively related to surface calcium carbonate and positively related to subsurface clay content. Thus, only a fraction of the landscape was susceptible to vegetation change, and the sparsely vegetated area probably featured a higher frequency of susceptible soil patches. Patch dynamics and self-organizing processes can be constrained by subtle (and often unrecognized) soil heterogeneity.

Spatial–temporal changes in potential evaporation patterns based on the Cloud model and their possible causes

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

Zhu, Yuelu; Huang, Shengzhi; Chang, Jianxia

It is of importance to comprehensively investigate the spatial-temporal changes in potential evaporation patterns, which helps guide the long-term water resource allocation and irrigation managements. In this study, the Cloud model was adopted to quantify the average, uniformity, and stability of annual potential evaporation in the Wei River Basin (WRB), a typical arid and semi-arid region in China.. The cross wavelet analysis was then applied to explore the correlations between potential evaporation and Arctic Oscillation (AO)/El Niño Southern Oscillation (ENSO) with an aim to determine the possible causes of potential evaporation variations. Results indicated that: (1) the average of annualmore » potential evaporation in the WRB first declined and then increased, which was similar with its stability, whilst its dispersion degree exhibited a decreasing trend, implying that potential evaporation has a small inter-annual variation; (2) the average of potential evaporation in the western basin was obviously smaller than that in the other areas, while its uniformity and stability in the Guanzhong plain and the Loess Plateau areas are larger than those in other areas, particularly in the western basin where the uniformity and stability are the smallest; (3) both AO and ENSO exhibited strong correlations with potential evaporation variations, indicating that both AO and ENSO have played an important role in the annual potential evaporation variations in the WRB.« less

Category learning increases discriminability of relevant object dimensions in visual cortex.

PubMed

Folstein, Jonathan R; Palmeri, Thomas J; Gauthier, Isabel

2013-04-01

Learning to categorize objects can transform how they are perceived, causing relevant perceptual dimensions predictive of object category to become enhanced. For example, an expert mycologist might become attuned to species-specific patterns of spacing between mushroom gills but learn to ignore cap textures attributable to varying environmental conditions. These selective changes in perception can persist beyond the act of categorizing objects and influence our ability to discriminate between them. Using functional magnetic resonance imaging adaptation, we demonstrate that such category-specific perceptual enhancements are associated with changes in the neural discriminability of object representations in visual cortex. Regions within the anterior fusiform gyrus became more sensitive to small variations in shape that were relevant during prior category learning. In addition, extrastriate occipital areas showed heightened sensitivity to small variations in shape that spanned the category boundary. Visual representations in cortex, just like our perception, are sensitive to an object's history of categorization.

Drinking-water quality and variations in water levels in the fractured crystalline-rock aquifer, west-central Jefferson County, Colorado. Water-resources investigations (interim)

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

Hall, D.C.; Johnson, C.J.

1979-09-01

In parts of the area, water for domestic use obtained from the fractured crystalline-rock aquifer contained excessive concentrations of dissolved fluoride, dissolved nitrite plus nitrate, dissolved solids, dissolved iron, dissolved manganese, dissolved zinc, coliform bacteria, gross alpha radiation, and gross beta radiation. Based on water-quality analyses from 26 wells located in small urbanized areas, water from 21 of the wells contained excessive concentrations of one or more constituents. Local variations in concentrations of 15 chemical constituents, specific conductance, and water temperature were statistically significant. Depths to water in 11 non-pumping wells ranged from 1 to 15 feet annually. Three-year trendsmore » in water-level changes in 6 of the 11 wells indicated a decrease in stored water in the aquifer.« less

The Effects of Magnetic-Field Geometry on Longitudinal Oscillations of Solar Prominences: Cross-Sectional Area Variation for Thin Tubes

NASA Technical Reports Server (NTRS)

Luna, M.; Diaz, A. J.; Oliver, R.; Terradas, J.; Karpen, J.

2016-01-01

Solar prominences are subject to both field-aligned (longitudinal) and transverse oscillatory motions, as evidenced by an increasing number of observations. Large-amplitude longitudinal motions provide valuable information on the geometry of the filament channel magnetic structure that supports the cool prominence plasma against gravity. Our pendulum model, in which the restoring force is the gravity projected along the dipped field lines of the magnetic structure, best explains these oscillations. However, several factors can influence the longitudinal oscillations, potentially invalidating the pendulum model. Aims. The aim of this work is to study the influence of large-scale variations in the magnetic field strength along the field lines, i.e., variations of the cross-sectional area along the flux tubes supporting prominence threads. Methods. We studied the normal modes of several flux tube configurations, using linear perturbation analysis, to assess the influence of different geometrical parameters on the oscillation properties. Results. We found that the influence of the symmetric and asymmetric expansion factors on longitudinal oscillations is small.Conclusions. We conclude that the longitudinal oscillations are not significantly influenced by variations of the cross-section of the flux tubes, validating the pendulum model in this context.

The relationship between observational scale and explained variance in benthic communities

PubMed Central

Flood, Roger D.; Frisk, Michael G.; Garza, Corey D.; Lopez, Glenn R.; Maher, Nicole P.

2018-01-01

This study addresses the impact of spatial scale on explaining variance in benthic communities. In particular, the analysis estimated the fraction of community variation that occurred at a spatial scale smaller than the sampling interval (i.e., the geographic distance between samples). This estimate is important because it sets a limit on the amount of community variation that can be explained based on the spatial configuration of a study area and sampling design. Six benthic data sets were examined that consisted of faunal abundances, common environmental variables (water depth, grain size, and surficial percent cover), and sonar backscatter treated as a habitat proxy (categorical acoustic provinces). Redundancy analysis was coupled with spatial variograms generated by multiscale ordination to quantify the explained and residual variance at different spatial scales and within and between acoustic provinces. The amount of community variation below the sampling interval of the surveys (< 100 m) was estimated to be 36–59% of the total. Once adjusted for this small-scale variation, > 71% of the remaining variance was explained by the environmental and province variables. Furthermore, these variables effectively explained the spatial structure present in the infaunal community. Overall, no scale problems remained to compromise inferences, and unexplained infaunal community variation had no apparent spatial structure within the observational scale of the surveys (> 100 m), although small-scale gradients (< 100 m) below the observational scale may be present. PMID:29324746

The impact of temperature and precipitation on blacklegged tick activity and Lyme disease incidence in endemic and emerging regions.

PubMed

Burtis, James C; Sullivan, Patrick; Levi, Taal; Oggenfuss, Kelly; Fahey, Timothy J; Ostfeld, Richard S

2016-11-25

The incidence of Lyme disease shows high degrees of inter-annual variation in the northeastern United States, but the factors driving this variation are not well understood. Complicating matters, it is also possible that these driving factors may vary in regions with differing histories of Lyme disease endemism. We evaluated the effect of the number of hot (T > 25 °C), dry (precipitation = 0) days during the questing periods of the two immature Ixodes scapularis life stages (larval and nymphal) on inter-annual variation in Lyme disease incidence between 2000 and 2011 in long-term endemic versus recently endemic areas. We also evaluated the effect of summer weather on tick questing activity and the number of ticks found on small mammals between 1994 and 2012 on six sites in Millbrook, NY. The number of hot, dry days during the larval period of the previous year did not affect the human incidence of Lyme disease or the density of questing nymphs the following season. However, dry summer weather during the nymphal questing period had a significant negative effect on the incidence of Lyme disease in the long-term endemic areas, and on the density of questing nymphs. Summer weather conditions had a more pronounced effect on actively questing I. scapularis collected via dragging than on the number of ticks found feeding on small mammals. In recently endemic areas Lyme disease incidence increased significantly over time, but no trend was detected between disease incidence and dry summer weather. Recently endemic regions showed an increase in Lyme disease incidence over time, while incidence in long-term endemic regions appears to have stabilized. Only within the stabilized areas were we able to detect reduced Lyme disease incidence in years with hot, dry summer weather. These patterns were reflected in our field data, which showed that questing activity of nymphal I. scapularis was reduced by hot, dry summer weather.

Interannual variability of sorted bedforms in the coastal German Bight (SE North Sea)

NASA Astrophysics Data System (ADS)

Mielck, F.; Holler, P.; Bürk, D.; Hass, H. C.

2015-12-01

Sorted bedforms are ubiquitous on the inner continental shelves worldwide. They are described as spatially-grain-size-sorted features consisting of small rippled medium-to-coarse sand and can remain stable for decades. However, the knowledge about their genesis and development is still fragmentary. For this study, a representative investigation area (water depth<15 m) located on the shelf west of the island of Sylt (SE North Sea, Germany) was periodically surveyed with hydroacoustic means (i.e. sidescan sonar, multibeam echo sounder, and sub-bottom profiler) during 2010-2014. Since this area is influenced by tidal and wind-driven currents, the aim was to detect and examine interannual variabilities in the characteristics of the prevailing sorted bedforms. Our measurements reveal sinuous stripes of rippled medium sand which are embedded in shallow symmetrical depressions. These domains are surrounded by relatively smooth fine-sand areas. These sorted bedforms were identified as flow-transverse features that are maintained by ebb and flood currents of almost equal strengths that flow in opposite directions. This bidirectional flow field generates sharp boundaries between the medium- and fine-sand domains in both current directions. Further to the north, where flood currents are dominant, asymmetric sorted bedforms were detected which show sharp boundaries only in flood-current direction. Comparisons between the measurements of the different years show no significant variations in morphology and distribution of the sorted bedforms. However, variations of the boundaries between the medium and the fine-sand domains were observed. Additionally, new minor sorted bedforms and rippled excavation marks as well as new fine-sand areas developed and disappeared occasionally. It can be supposed that such sediment winnowing and focusing processes take place during periodically recurring storm surges, which change the shapes of the features. Moreover, variations in alignments and sizes of the small ripple formations were detected. They seem to indicate the directions and intensities of previous storm events.

A multiple wavelet coherency method for temporal streamflow-precipitation-temperature relationships in 17 small catchments on the Loess Plateau, China

NASA Astrophysics Data System (ADS)

Yang, Y.; Liu, B.

2017-12-01

Climate change and human activities are two critical factors causing the dramatical variations of streamflow in the Yellow River Basin of China during the last several decades. More and more attention has been paid to the temporal relationships of streamflow with precipitation and temperature recently. The objective of the current study was to explore the contributions of precipitation and temperature to the temporal variations of streamflow on the Loess Plateau using a multiple wavelet coherency method. Annual streamflow during 1961-2013 for 17 small catchments were collected from the Yellow River Conservancy Commission and annual precipitation and temperature for each catchment were derived from the meteorological data at the national weather stations across the Loess Plateau through the China Meteorological Data Sharing Service System. An abrupt decrease was observed in the annual streamflow around year 2000 for any of the 17 catchments investigated, which was believed to be related with the extensive Grain for Green Project. According to bivariate wavelet coherences, however, annual streamflow showed strong temporal variations with annual precipitation at 8 out of the 17 catchments, where the percentage area of significant coherency (PASC) exceeded 50%. Especially in Weihe and Yiluohe catchments, the corresponding PASC were close to 100%, suggesting that annual precipitation change accounted for almost all the temporal streamflow variations. Compared to annual precipitation, the temporal correlation of temperature with streamflow was relatively small, as implied in the lower mean wavelet coherence (MWC) and PASC. Moreover, including temperature in addition to precipitation in the multiple wavelet coherency analysis failed to increase either MWC or PASC in any of the 17 catchments except for Qingjianhe and Qiushuihe catchments. It was indicated that for most catchments on the Loess Plateau, annual temperature was not significantly different from the red noise in explaining the additional variation in streamflow. In view of the small PASC values resulted for most catchments, there existed other environmental and/or anthropogenic factors responsible for the temporal variations of streamflow.

Regional Inequalities in Lung Cancer Mortality in Belgium at the Beginning of the 21st Century: The Contribution of Individual and Area-Level Socioeconomic Status and Industrial Exposure.

PubMed

Hagedoorn, Paulien; Vandenheede, Hadewijch; Willaert, Didier; Vanthomme, Katrien; Gadeyne, Sylvie

2016-01-01

Being a highly industrialized country with one of the highest male lung cancer mortality rates in Europe, Belgium is an interesting study area for lung cancer research. This study investigates geographical patterns in lung cancer mortality in Belgium. More specifically it probes into the contribution of individual as well as area-level characteristics to (sub-district patterns in) lung cancer mortality. Data from the 2001 census linked to register data from 2001-2011 are used, selecting all Belgian inhabitants aged 65+ at time of the census. Individual characteristics include education, housing status and home ownership. Urbanicity, unemployment rate, the percentage employed in mining and the percentage employed in other high-risk industries are included as sub-district characteristics. Regional variation in lung cancer mortality at sub-district level is estimated using directly age-standardized mortality rates. The association between lung cancer mortality and individual and area characteristics, and their impact on the variation of sub-district level is estimated using multilevel Poisson models. Significant sub-district variations in lung cancer mortality are observed. Individual characteristics explain a small share of this variation, while a large share is explained by sub-district characteristics. Individuals with a low socioeconomic status experience a higher lung cancer mortality risk. Among women, an association with lung cancer mortality is found for the sub-district characteristics urbanicity and unemployment rate, while for men lung cancer mortality was associated with the percentage employed in mining. Not just individual characteristics, but also area characteristics are thus important determinants of (regional differences in) lung cancer mortality.

Changes in the Seismicity and Focal Mechanism of Small Earthquakes Prior to an MS 6.7 Earthquake in the Central Aleutian Island Arc

USGS Publications Warehouse

Billington, Serena; Engdahl, E.R.; Price, Stephanie

1981-01-01

On November 4 1977, a magnitude Ms 6.7 (mb 5.7) shallow-focus thrust earthquake occurred in the vicinity of the Adak seismographic network in the central Aleutian island arc. The earthquake and its aftershock sequence occurred in an area that had not experienced a similar sequence since at least 1964. About 13 1/2 months before the main shock, the rate of occurrence of very small magnitude earthquakes increased abruptly in the immediate vicinity of the impending main shock. To search for possible variations in the focal mechanism of small events preceding the main shock, a method was developed that objectively combines first-motion data to generate composite focal-mechanism information about events occurring within a small source region. The method could not be successfully applied to the whole study area, but the results show that starting about 10 1/2 months before the November 1977 earthquake, there was a change in the mechanism of small- to moderate-sized earthquakes in the immediate vicinity of the hypocenter and possibly in other parts of the eventual aftershock zone, but not in the surrounding regions.

Improving the nowcasting of precipitation in an Alpine region with an enhanced radar echo tracking algorithm

NASA Astrophysics Data System (ADS)

Mecklenburg, S.; Joss, J.; Schmid, W.

2000-12-01

Nowcasting for hydrological applications is discussed. The tracking algorithm extrapolates radar images in space and time. It originates from the pattern recognition techniques TREC (Tracking Radar Echoes by Correlation, Rinehart and Garvey, J. Appl. Meteor., 34 (1995) 1286) and COTREC (Continuity of TREC vectors, Li et al., Nature, 273 (1978) 287). To evaluate the quality of the extrapolation, a parameter scheme is introduced, able to distinguish between errors in the position and the intensity of the predicted precipitation. The parameters for the position are the absolute error, the relative error and the error of the forecasted direction. The parameters for the intensity are the ratio of the medians and the variations of the rain rate (ratio of two quantiles) between the actual and the forecasted image. To judge the overall quality of the forecast, the correlation coefficient between the forecasted and the actual radar image has been used. To improve the forecast, three aspects have been investigated: (a) Common meteorological attributes of convective cells, derived from a hail statistics, have been determined to optimize the parameters of the tracking algorithm. Using (a), the forecast procedure modifications (b) and (c) have been applied. (b) Small-scale features have been removed by using larger tracking areas and by applying a spatial and temporal smoothing, since problems with the tracking algorithm are mainly caused by small-scale/short-term variations of the echo pattern or because of limitations caused by the radar technique itself (erroneous vectors caused by clutter or shielding). (c) The searching area and the number of searched boxes have been restricted. This limits false detections, which is especially useful in stratiform precipitation and for stationary echoes. Whereas a larger scale and the removal of small-scale features improve the forecasted position for the convective precipitation, the forecast of the stratiform event is not influenced, but limiting the search area leads to a slightly better forecast. The forecast of the intensity is successful for both precipitation events. Forecasting the variation of the rain rate calls for further investigation. Applying COTREC improves the forecast of the convective precipitation, especially for extrapolation times exceeding 30 min.

Small-scale Conformity of the Virgo Cluster Galaxies

NASA Astrophysics Data System (ADS)

Lee, Hye-Ran; Lee, Joon Hyeop; Jeong, Hyunjin; Park, Byeong-Gon

2016-06-01

We investigate the small-scale conformity in color between bright galaxies and their faint companions in the Virgo Cluster. Cluster member galaxies are spectroscopically determined using the Extended Virgo Cluster Catalog and the Sloan Digital Sky Survey Data Release 12. We find that the luminosity-weighted mean color of faint galaxies depends on the color of adjacent bright galaxy as well as on the cluster-scale environment (gravitational potential index). From this result for the entire area of the Virgo Cluster, it is not distinguishable whether the small-scale conformity is genuine or if it is artificially produced due to cluster-scale variation of galaxy color. To disentangle this degeneracy, we divide the Virgo Cluster area into three sub-areas so that the cluster-scale environmental dependence is minimized: A1 (central), A2 (intermediate), and A3 (outermost). We find conformity in color between bright galaxies and their faint companions (color-color slope significance S ˜ 2.73σ and correlation coefficient {cc}˜ 0.50) in A2, where the cluster-scale environmental dependence is almost negligible. On the other hand, the conformity is not significant or very marginal (S ˜ 1.75σ and {cc}˜ 0.27) in A1. The conformity is not significant either in A3 (S ˜ 1.59σ and {cc}˜ 0.44), but the sample size is too small in this area. These results are consistent with a scenario in which the small-scale conformity in a cluster is a vestige of infallen groups and these groups lose conformity as they come closer to the cluster center.

Preliminary report on macroscopic age changes in the human prosencephalon. A stereologic investigation.

PubMed

Eggers, R; Haug, H; Fischer, D

1984-01-01

The studies here reported were performed on the prosencephalons of 12 human brains between 37 and 86 years of age having no signs of neuropathological alteration. The evaluation was carried out on serial frontal sections with a mean thickness of 5 mm with stereological point counting procedures for volume and surface area. The results were mainly given in relative values since the range of variation is very high and the sample small. The aging process was evaluated with the aid of a linear regression function. The stereological investigation regarding the absolute values of volume and surface area (border face) of the macroscopical brain parts show a high interindividual variability. However, the relative volume of brain parts shows only small variations. Changes during aging could consequently only be revealed with the help of the relative values. The relative volumes and surface areas of the frontal lobe and the prosencephalic ganglia decrease with aging, while the parieto-occipital lobe and the striate cortex increase. However, if we refer these relative increases to the absolute decrease of brain volume, corresponding changes cannot be found in the parieto-occipital lobe until old age. The shrinkage of the frontal lobe, of the centrum semiovale and of the prosencephalic ganglia exceeds 10%. In the grays it is probably accompanied by a loss of neurons. The relative sizes of the surface area do not change significantly during aging with exception of the frontal cortex. The thickness of the cortex remains probably constant. The size of lateral ventricles increases with aging.

A tale of swinger insects: Signatures of past sexuality between divergent lineages of a parthenogenetic weevil revealed by ribosomal intraindividual variation.

PubMed

Rodriguero, Marcela S; Wirth, Sonia A; Alberghina, Josefina S; Lanteri, Analía A; Confalonieri, Viviana A

2018-01-01

Naupactus cervinus (Boheman) (Curculionidae, Naupactini) is a parthenogenetic weevil native to the Paranaense Forest which displays high levels of genetic variation. Two divergent clades were identified, one ranging in forest areas (Forest clade), and the other in open vegetation areas (Grassland clade). Both of them have individuals with high levels of heterozygosity in ribosomal sequences. Investigation of intraindividual variation in ITS1 sequences through cloning and posterior sequencing suggested that mating between both groups most likely occurred in the Paranaense Forest after a secondary contact, which led to fixed heterozygotes as a consequence of parthenogenesis. Otherwise, sexual segregation would have disrupted multilocus genotypes. Only a small number of heterozygous genotypes of all the possible combinations are found in nature. We propose the occurrence of a hybrid zone in the Paranaense Forest. The fact that it is one of the most important biodiversity hotspots of the world, together with its key role for investigating evolutionary processes, makes it worthy of conservation. This is the first genetic evidence of bisexuality in N. cervinus.

Variation in Chemotherapy Utilization in Ovarian Cancer: The Relative Contribution of Geography

PubMed Central

Polsky, Daniel; Armstrong, Katrina A; Randall, Thomas C; Ross, Richard N; Even-Shoshan, Orit; Rosenbaum, Paul R; Silber, Jeffrey H

2006-01-01

Objective This study investigates geographic variation in chemotherapy utilization for ovarian cancer in both absolute and relative terms and examines area characteristics associated with this variation. Data Sources Surveillance, Epidemiology, and End Results (SEER) Medicare data from 1990 to 2001 for Medicare patients over 65 with a diagnosis of ovarian cancer between 1990 and 1999. Chemotherapy within a year of diagnosis was identified by Medicare billing codes. The hospital referral region (HRR) represents the geographic unit of analysis. Study Design A logit model predicting the probability of receiving chemotherapy by each of the 39 HRRs. Control variables included medical characteristics (patient age, stage, year of diagnosis, and comorbidities) and socioeconomic characteristics (race, income, and education). The variation among HRRs was tested by the χ2 statistic, and the relative contribution was measured by the ω statistic. HHR market characteristic are then used to explain HRR-level variation. Principal Findings The average chemotherapy rate was 56.6 percent, with a range by HRR from 33 percent to 67 percent. There were large and significant differences in chemotherapy use between HRRs, reflected by a χ2 for HRR of 146 (df=38, p<.001). HRR-level variation in chemotherapy use can be partially explained by higher chemotherapy rates in HRRs with a higher percentage of hospitals with oncology services. However, an ω analysis indicates that, by about 15 to one, the variation between patients in use of chemotherapy reflects variations in patient characteristics rather than unexplained variation among HRRs. Conclusions While absolute levels of chemotherapy variation between geographic areas are large and statistically significant, this analysis suggests that the role of geography in determining who gets chemotherapy is small relative to individual medical characteristics. Nevertheless, while variation by medical characteristics can be medically justified, the same cannot be said for geographic variation. Our finding that density of oncology hospitals predicts chemotherapy use suggests that provider supply is positively correlated with geographic variation. PMID:17116116

Water-quality assessment of the Rio Grande Valley, Colorado, New Mexico, and Texas : shallow ground-water quality and land use in the Albuquerque area, central New Mexico, 1993

USGS Publications Warehouse

Anderholm, Scott K.

1997-01-01

This report describes the quality of shallow ground water and the relations between land use and the quality of that shallow ground water in an urban area in and adjacent to Albuquerque, New Mexico. Water samples were collected from 24 shallow wells. Samples were analyzed for selected common constituents, nutrients, trace elements, radionuclides, volatile organic compounds, and pesticides. The study area, which is in the Albuquerque Basin in central New Mexico, was limited to the Rio Grande flood plain; depth to water in this area generally is less than 25 feet. The amount and composition of recharge to the shallow ground-water system are important factors that affect shallow ground-water composition in this area. Important sources of recharge that affect shallow ground-water quality in the area include infiltration of surface water, which is used in agricultural land-use areas to irrigate crops, and infiltration of septic-system effluent in residential areas. Agricultural land use represents about 28 percent of the area, and residential land use represents about 35 percent of the total study area. In most of the study area, agricultural land use is interspersed with residential land use and neither is the dominant land use in the area. Land use in the study area historically has been changing from agricultural to urban. The composition of shallow ground water in the study area varies considerably. The dissolved solids concentration in shallow ground water in the study area ranges from 272 to 1,650 milligrams per liter, although the relative percentages of selected cations and anions do not vary substantially. Calcium generally is the dominant cation and bicarbonate generally is the dominant anion. Concentrations of nutrients generally were less than 1 milligram per liter. The concentration of many trace elements in shallow ground water was below or slightly above 1 microgram per liter and there was little variation in the concentrations. Barium, iron, manganese, molybdenum, and uranium were the only trace elements analyzed for that had median concentrations greater than 5 micrograms per liter. Volatile organic compounds were detected in 5 of 24 samples. Cis-1,2-dichloroethene and 1,1-dichloroethane were the most commonly detected volatile organic compounds (detected in two samples each). Pesticides were detected in 8 of 24 samples. Prometon was the most commonly detected pesticide (detected in 5 of 24 samples). Concentrations of volatile organic compounds and pesticides detected were much smaller than any U.S. Environmental Protection Agency standards that have been established. Infiltration of surface water and the evaporation or transpiration of this water, which partially is the result of past and present agricultural land use, seem to affect the concentrations of common constituents in shallow ground water in the study area. The small excess chloride in shallow ground water relative to surface water that has been affected by evaporation or transpiration could be due to mixing of shallow ground water with small amounts of precipitation/bulk deposition or septic-system effluent. Infiltration of septic-system effluent (residential land use) has affected the shallow ground-water composition in parts of the study area on the basis of the small dissolved oxygen concentrations, large dissolved organic carbon concentrations, and excess chloride. Despite the loading of nitrogen to the shallow ground-water system as the result of infiltration of septic-system effluent, the small nitrogen concentrations in shallow ground water probably are due to the small dissolved oxygen concentrations and relatively large dissolved organic carbon concentrations. The small concentrations and lack of variation of most trace elements indicate that land use has not substantially affected the concentration

Small-Area Estimation of Spatial Access to Care and Its Implications for Policy.

PubMed

Gentili, Monica; Isett, Kim; Serban, Nicoleta; Swann, Julie

2015-10-01

Local or small-area estimates to capture emerging trends across large geographic regions are critical in identifying and addressing community-level health interventions. However, they are often unavailable due to lack of analytic capabilities in compiling and integrating extensive datasets and complementing them with the knowledge about variations in state-level health policies. This study introduces a modeling approach for small-area estimation of spatial access to pediatric primary care that is data "rich" and mathematically rigorous, integrating data and health policy in a systematic way. We illustrate the sensitivity of the model to policy decision making across large geographic regions by performing a systematic comparison of the estimates at the census tract and county levels for Georgia and California. Our results show the proposed approach is able to overcome limitations of other existing models by capturing patient and provider preferences and by incorporating possible changes in health policies. The primary finding is systematic underestimation of spatial access, and inaccurate estimates of disparities across population and across geography at the county level with respect to those at the census tract level with implications on where to focus and which type of interventions to consider.

Chloride mass-balance method for estimating ground water recharge in arid areas: examples from western Saudi Arabia

NASA Astrophysics Data System (ADS)

Bazuhair, Abdulghaffar S.; Wood, Warren W.

1996-11-01

The chloride mass-balance method, which integrates time and aerial distribution of ground water recharge, was applied to small alluvial aquifers in the wadi systems of the Asir and Hijaz mountains in western Saudi Arabia. This application is an extension of the method shown to be suitable for estimating recharge in regional aquifers in semi-arid areas. Because the method integrates recharge in time and space it appears to be, with certain assumptions, particularly well suited for and areas with large temporal and spatial variation in recharge. In general, recharge was found to be between 3 to 4% of precipitation — a range consistent with recharge rates found in other and and semi-arid areas of the earth.

Chloride mass-balance method for estimating ground water recharge in arid areas: Examples from western Saudi Arabia

USGS Publications Warehouse

Bazuhair, A.S.; Wood, W.W.

1996-01-01

The chloride mass-balance method, which integrates time and aerial distribution of ground water recharge, was applied to small alluvial aquifers in the wadi systems of the Asir and Hijaz mountains in western Saudi Arabia. This application is an extension of the method shown to be suitable for estimating recharge in regional aquifers in semi-arid areas. Because the method integrates recharge in time and space it appears to be, with certain assumptions, particularly well suited for and areas with large temporal and spatial variation in recharge. In general, recharge was found to be between 3 to 4% of precipitation - a range consistent with recharge rates found in other arid and semi-arid areas of the earth.

Diversity and Assembling Processes of Bacterial Communities in Cryoconite Holes of a Karakoram Glacier.

PubMed

Ambrosini, Roberto; Musitelli, Federica; Navarra, Federico; Tagliaferri, Ilario; Gandolfi, Isabella; Bestetti, Giuseppina; Mayer, Christoph; Minora, Umberto; Azzoni, Roberto Sergio; Diolaiuti, Guglielmina; Smiraglia, Claudio; Franzetti, Andrea

2017-05-01

Cryoconite holes are small ponds that form on the surface of glaciers that contain a dark debris, the cryoconite, at the bottom and host active ecological communities. Differences in the structure of bacterial communities have been documented among Arctic and mountain glaciers, and among glaciers in different areas of the world. In this study, we investigated the structure of bacterial communities of cryoconite holes of Baltoro Glacier, a large (62 km in length and 524 km 2 of surface) glacier of the Karakoram, by high-throughput sequencing of the V5-V6 hypervariable regions of the 16S rRNA gene. We found that Betaproteobacteria dominated bacterial communities, with large abundance of genera Polaromonas, probably thanks to its highly versatile metabolism, and Limnohabitans, which may have been favoured by the presence of supraglacial lakes in the area where cryoconite holes were sampled. Variation in bacterial communities among different sampling areas of the glacier could be explained by divergent selective processes driven by variation in environmental conditions, particularly pH, which was the only environmental variable that significantly affected the structure of bacterial communities. This variability may be due to both temporal and spatial patterns of variation in environmental conditions.

Generating Health Estimates by Zip Code: A Semiparametric Small Area Estimation Approach Using the California Health Interview Survey.

PubMed

Wang, Yueyan; Ponce, Ninez A; Wang, Pan; Opsomer, Jean D; Yu, Hongjian

2015-12-01

We propose a method to meet challenges in generating health estimates for granular geographic areas in which the survey sample size is extremely small. Our generalized linear mixed model predicts health outcomes using both individual-level and neighborhood-level predictors. The model's feature of nonparametric smoothing function on neighborhood-level variables better captures the association between neighborhood environment and the outcome. Using 2011 to 2012 data from the California Health Interview Survey, we demonstrate an empirical application of this method to estimate the fraction of residents without health insurance for Zip Code Tabulation Areas (ZCTAs). Our method generated stable estimates of uninsurance for 1519 of 1765 ZCTAs (86%) in California. For some areas with great socioeconomic diversity across adjacent neighborhoods, such as Los Angeles County, the modeled uninsured estimates revealed much heterogeneity among geographically adjacent ZCTAs. The proposed method can increase the value of health surveys by providing modeled estimates for health data at a granular geographic level. It can account for variations in health outcomes at the neighborhood level as a result of both socioeconomic characteristics and geographic locations.

The relationship between elastomer opacity, colorimeter beam size, and measured colorimetric response.

PubMed

Rugh, E H; Johnston, W M; Hesse, N S

1991-01-01

The effect of opacity on the colorimetric responses of large-area and small-area colorimeters was determined using an elastomer intended for maxillofacial prosthetics use and containing various pigments at different concentrations. Opacity was determined by calculating the contrast ratio of 2-mm-thick specimens against black and white backings, using Kubelka-Munk analyses to correct for thickness and backing color variations. The measure of comparison of the two colorimeters was the relative difference in tristimulus reflectance, with the tristimulus reflectance of the large-area colorimeter as the basis of the relative difference. A significant quadratic relationship was found between contrast ratio and the relative difference in tristimulus reflectance. This relationship may be used to describe opacity without the need to make optical observations or measurements of a thin layer of material on contrasting backings. The small-area colorimeter produced color parameters that are a measure of the combined effects of both color and opacity. The importance of beam size considerations of optical measuring devices for translucent natural and prosthetic materials was emphasized.

Assessment of the magnitude of geographical variations in the duration of non-work-related sickness absence by individual and contextual factors.

PubMed

Torá-Rocamora, Isabel; Martínez, José Miguel; Gimeno, David; Alberti, Constança; Jardí, Josefina; Manzanera, Rafael; Benavides, Fernando G; Delclos, George

2015-01-01

To examine variation in the duration of non-work-related sickness absence (NWRSA) across geographical areas and the degree to which this variation can be explained by individual and/or contextual factors. All first NWRSA episodes ending in 2007 and 2010 were analyzed. Individual (diagnosis, age, sex) and contextual factors (healthcare resources, socioeconomic factors) were analyzed to assess how much of the geographical variation was explained by these factors. Median NWRSA durations in quartiles were mapped by counties in Catalonia. Multilevel Cox proportional hazard regression models with episodes nested within counties were fitted to quantify the magnitude of this variation. The proportional change in variance (PCV), median hazard ratios (MHR) and interquartile hazard ratios (IHR) were calculated. We found a geographical pattern in the duration of NWRSA, with longer duration in northwestern Catalonia. There was a small, but statistically significant, geographical variation in the duration of NWRSA, which mostly decreased after adjustment for individual factors in both women (PCV=34.98%, MHR=1.09, IHR=1.13 in 2007; PCV=34.68%, MHR=1.11, IHR=1.28 in 2010) and men (PCV=39.88%, MHR=1.10, IHR=1.27 in 2007; PCV=45.93%, MHR=1.10, IHR=1.25 in 2010); only in the case of women in 2010 was there a reduction in county-level variance due to contextual covariates (PCV=16.18%, MHR=1.12, IHR=1.32). County-level variation in the duration of NWRSA was small and was explained more by individual than by contextual variables. Knowledge of geographic differences in NWRSA duration is needed to plan specific programs and interventions to minimize these differences. Copyright © 2014 SESPAS. Published by Elsevier Espana. All rights reserved.

Some relations between streamflow characteristics and the environment in the Delaware River region

USGS Publications Warehouse

Hely, A.G.; Olmsted, F.H.

1963-01-01

Streamflow characteristics are determined by a large number of factors of the meteorological and terrestrial environments. Because of lack of quantitative data to describe some of the factors and complex interrelations among them, complete analysis of the relations between streamflow and the various environmental factors is impossible. However, certain simplifying assumptions and generalizations made possible a partial analysis for the Delaware River region. For relations involving average runoff or low-flow parameters, average annual precipitation was assumed to be the principal meteorological factor, and geology (a complex of many factors) was assumed to be the principal terrestrial influence, except for that of basin size which was largely eliminated by expression of discharge in terms of unit area. As a first approximation, physiographic units were used as a basis for classifying the geology. Relations between flow parameters and precipitation are fairly well defined for some physiographic units, but not for those in which the geology varies markedly or the areal variation in average precipitation is very small. These relations provide a basis for adjusting the flow parameters to reduce or eliminate the effects of areal variations in precipitation and increase their significance in studies of the effects of terrestrial characteristics. An investigation of the residual effect of basin size (the effect remaining when discharge is expressed in terms of unit area) on relations between flow parameters and average precipitation indicates that such effect is negligible, except for very large differences in area. Parameters that are derived from base-flow recession curves and are related to a common discharge per unit area have inherent advantages as indicators of effects of terrestrial characteristics of basins, because the.y are independent of areal variations in average annual precipitation. Winter base-flow parameters are also practically independent of the effects of evapotranspiration from ground water. However, in many parts of the region these advantages are reduced or nullified by the difficulties of defining base-flow recession curves, particularly winter curves, with sufficient accuracy. In the absence of suitable base-flow recession data and a suitable basis for adjusting parameters, the ratio of the discharge equaled or exceeded 90 percent of the time to the average discharge (Qtt/Qa), or a similar duration parameter, probably is the best indicator of the influence of terrestrial characteristics, although the ratio may vary somewhat with average precipitation. In a part of the region where geologic differences are large and areal variations in average precipitation are small, values of Qm/Qa for each major geologic unit were determined from streamflow records. From these values and the percentage of area represented by each unit, a ratio for each gaging station was computed. Comparison of these computed results with the observed results indicates that nearly all of the variation in the ratio is associated with variation in geology. The investigation indicates that the original assumptions are correct; average precipitation is the principal meteorological influence and geology is the principal terrestrial influence. Together these two factors account for a very large proportion of the variation in average runoff and low-flow characteristics

Characterisation of Seasonal Temperature Variation in a Shallow, Urban Aquifer: Implications for the Sustainable Development of Ground Source Heating Systems

NASA Astrophysics Data System (ADS)

Patton, Ashley M.; Farr, Gareth J.; Boon, David P.; James, David R.

2017-04-01

Groundwater thermally enhanced by the Urban Heat Island effect can be utilised by ground source heating systems (GSHSs). However, the near subsurface is subject to seasonal temperature variation reflected in shallow groundwater that can differ by several degrees throughout the year. To sustainably manage the near surface thermal resource an understanding of factors which control variation in groundwater temperature and how these are transmitted through the aquifer is needed. We show that even in relatively small urban areas (Cardiff, U.K., situated on a shallow gravel aquifer) the Zone of Seasonal Fluctuation (ZSF) can vary in depth by 8m. GSHSs are more efficient if they are sited below the ZSF, where temperatures are more stable. In Spring 2014, 48 groundwater monitoring boreholes were profiled at a 1m resolution to measure groundwater temperature across Cardiff. These were reprofiled that Autumn and compared to the Spring temperatures, defining the ZSF. The average depth to the base of the ZSF was 9.5mbgl but ranged from 7.1-15.5mbgl. The amplitude of the differences between Spring and Autumn temperatures also varied. To better understand the high spatial variability 60 boreholes were instrumented with in situ temperature loggers, recording at half-hourly intervals. The first year's data revealed the amplitudes of temperature variation within boreholes with loggers at similar depths were not always consistent. It was also noted that lag times between air temperature and groundwater temperature were not uniform across the sites. The data also showed that where gravels occurred at shallower depths the ZSF tended to be shallower and lag times shorter. The wide spatial variability of the ZSF may be partially explained by differing landuse. Those boreholes in open, grassed areas showed a deeper ZSF than those in built-up areas but built-up areas generally showed the greatest variation between Spring and Autumn temperature profiles, suggesting heat loss from buildings and underground infrastructure plays a part. Natural and anthropogenic factors affecting spatial and temporal groundwater temperatures, either separately or in combination, that have been considered in this study include landuse, depth, lithology/lithostratigraphy, material properties, hydrogeological setting, thermal conductivity, buried infrastructure, land surface temperature, weather effects and solar radiation. This study shows that urban groundwater temperatures can vary greatly across a small area, which has implications for the successful development, and long-term performance of open- and closed-loop GSHSs, and the environmental regulation of these systems. Key to the effective wide-scale use of GSHSs is an understanding of the hydrogeological setting, chiefly how heat is transferred across the aquifer. This study attempts to provide insight into an array of factors which determine heat transfer in the ZSF.

Peromyscus ranges at high and low population densities

USGS Publications Warehouse

Stickel, L.F.

1960-01-01

Live-trapping studies at the Patuxent Wildlife Research Center, Maryland, showed that the ranges of wood mice were larger when the population density was lower and smaller when the population density was higher. When the population density was about 1.3 male mice per acre in June 1954, the average distance recorded between traps after four or more captures was 258 feet. When the population density was about 4.1 male mice per acre in June 1957, the average distance was 119 feet. Differences were statistically significant. Females were so scarce at the low that comparisons could not be made for them. Examples from the literature also show that home range of a species may vary with population density. Other examples show that the range may vary with habitat, breeding condition and food supply. These variations in range size reduce the reliability of censuses in which relative methods are used: Lines of traps sample the population of a larger area when ranges are large than they do when ranges are small. Direct comparisons therefore will err in some degree. Error may be introduced also when line-trap data are transformed to per acre figures on the basis of home-range estimates made by area-trapping at another place or time. Variation in range size also can make it necessary to change area-trapping plans, for larger quadrants are needed when ranges are larger. It my be necessary to set traps closer together when ranges are small than when ranges are large.

Area variations in multiple morbidity using a life table methodology.

PubMed

Congdon, Peter

Analysis of healthy life expectancy is typically based on a binary distinction between health and ill-health. By contrast, this paper considers spatial modelling of disease free life expectancy taking account of the number of chronic conditions. Thus the analysis is based on population sub-groups with no disease, those with one disease only, and those with two or more diseases (multiple morbidity). Data on health status is accordingly modelled using a multinomial likelihood. The analysis uses data for 258 small areas in north London, and shows wide differences in the disease burden related to multiple morbidity. Strong associations between area socioeconomic deprivation and multiple morbidity are demonstrated, as well as strong spatial clustering.

Atmospheric 14 C CO 2 variations in Japan during 1982--1999 based on 14 C measurements of rice grains.

PubMed

Shibata, Setsuko; Kawano, Eiko; Nakabayashi, Takeshige

2005-08-01

(14)C in rice grains is a useful tracer of atmospheric (14)C(CO(2)). (14)C measurement in rice grains for 17 years during 1982--1999 reveals the following. There is negative correlation between Delta(14)C and the population densities of localities in Japan. Under-populated areas in the northern area of Japan and Okinawa remained clean in the 1990s. The (14)C(CO(2)) decline rates at those areas are near to that of Shauinsland. A latitudinal effect due to Chinese nuclear tests is observed in 1982. Small Seuss effects is observed at the middle latitudes in East Asia after 1995.

Temporal variations of natural soil salinity in an arid environment using satellite images

NASA Astrophysics Data System (ADS)

Gutierrez, M.; Johnson, E.

2010-11-01

In many remote arid areas the scarce amount of conventional soil salinity data precludes detailed analyses of salinity variations for the purpose of predicting its impact on agricultural production. A tool that is an appropriate surrogate for on-ground testing in determining temporal variations of soil salinity is Landsat satellite data. In this study six Landsat scenes over El Cuervo, a closed basin adjacent to the middle Rio Conchos basin in northern Mexico, were used to show temporal variation of natural salts from 1986 to 2005. Natural salts were inferred from ground reference data and spectral responses. Transformations used were Tasseled Cap, Principal Components and several (band) ratios. Classification of each scene was performed from the development of Regions Of Interest derived from geochemical data collected by SGM, spectral responses derived from ENVI software, and a small amount of field data collected by the authors. The resultant land cover classes showed a relationship between climatic drought and areal coverage of natural salts. When little precipitation occurred three months prior to the capture of the Landsat scene, approximately 15%-20% of the area was classified as salt. This is compared to practically no classified salt in the wetter years of 1992 and 2005 Landsat scenes.

Occurrence and partition ratios of radiocesium in an urban river during dry and wet weather after the 2011 nuclear accident in Fukushima.

PubMed

Murakami, Michio; Shibayama, Nao; Sueki, Keisuke; Mouri, Goro; O, Haechong; Nomura, Mihiro; Koibuchi, Yukio; Oki, Taikan

2016-04-01

After the 2011 nuclear accident in Fukushima, radiocesium was released from the Fukushima Dai-ichi Nuclear Power Plant and contaminated waters in urban areas near Tokyo. By intensive field monitoring during 3 years, this study investigated the temporal trends and the occurrence of radiocesium during dry and wet weather, and analyzed the variations in radiocesium during rainfall events and factors controlling them. Concentrations of particulate radiocesium decreased rapidly from May 2012 to March 2013 and reached an equilibrium in 2014. Concentrations of particulate (137)Cs during wet weather were almost double those during dry weather in the same period. In contrast to the small variations in (137)Cs concentrations in the particulate phase on a suspended solids (SS) weight basis during events, those in the dissolved phase on a liquid-volume basis fluctuated greatly, resulting in variations in the partition coefficient (apparent Kd). The apparent Kd of (137)Cs during wet weather ranged from 30,000 to 150,000 L kg(-1) and showed a significant negative correlation with SS concentrations during wet weather. Specific surface area in solids contributed to the variations in apparent Kd. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hydrological and Geochemical Influences on the Dissolved Silica Concentrations in Natural Water in a Steep Headwater Catchment

NASA Astrophysics Data System (ADS)

Asano, Y.; Uchida, T.; Ohte, N.

2002-12-01

Dissolved silica has been used as a useful indicator of a chemical weathering in many geochemical studies in natural environment. Previous hydrological studies indicated that various hydrological processes affect the dissolution and precipitation of silica in hillslope and transport of this silica to stream; however, information is still limited to link this knowledge to understand geochemical processes. The observations of dissolved silica concentration in groundwater, spring and stream water was conducted at the unchannelled hillslope in the Tanakami Mountains of central Japan; (1) to clarify the effects of preferential flowpaths including lateral and vertical flow in soil layer and flow through bedrock fracture in the variation of dissolved silica concentration in runoff and groundwater, and (2) to isolate the effects of mixing of water from geochemically diverse water sources on the dissolved silica concentration. The mean dissolved silica concentrations in soil water at 40 cm depth and transient groundwater formed in upslope area were relatively constant independent of the variation in the new water ratio. The mean dissolved silica concentrations were similar regardless of the sampling depth in soil although the mean residence times of water increase with depth. These results indicated that dissolved silica concentrations in soil water and transient groundwater were defined almost independent of contact time of water with minerals. While the mean dissolved silica concentration in perennial groundwater, which was recharged by infiltrating water through soil and water emerging from bedrock in a area near to spring, was more than twice that of transient groundwater and the variation was relatively large. The mean dissolved silica concentration increased significantly at downslope from perennial groundwater, spring to the stream and the spring and stream concentrations also showed large variation. The dissolved silica concentrations of those perennial groundwater, the spring and the stream was controlled by the mixing of water from soil and bedrock. Our results demonstrated that in most areas of this headwater catchment, the preferential flowpaths give only small effect on dissolved silica concentrations. While in a small area (less than 10% of the longitudinal axis of the hollow near the spring), the dissolved silica concentration were controlled by the mixing of water from geochemically diverse water sources.

Quantifying Diurnal and Seasonal Variation in On-road CO2 Emissions Across the Northeastern U.S.

NASA Astrophysics Data System (ADS)

Gately, C.; Hutyra, L.

2014-12-01

On-road emissions comprised 29% of U.S. fossil fuel carbon dioxide emissions in 2012, with 64% of those emissions occurring in urban areas. Understanding the social, economic and technological factors that influence urban emissions requires the development of emissions inventories that are resolved at fine spatial and temporal scales. As city governments are increasingly at the forefront of developing policies to mitigate greenhouse gas emissions from vehicles, high-resolution, bottom-up inventories will support local and regional emissions benchmarking, as well as the monitoring, reporting, and verification of trends in emissions across time and space. To that end, we combine a large regional dataset of hourly traffic counts with the 1km gridded estimates of on-road CO2 emissions from the Database of Road Transportation Emissions (DARTE) to develop hourly CO2 emissions estimates for the year 2012 that cover 12 northeastern states. The inventory scope covers several large metropolitan regions as well as many small- and medium-sized urban, suburban and exurban population centers, altogether representing 20% of urban and 17% of total U.S. on-road CO2 emissions in 2012. We identify significant variation in the time structure of vehicle emissions across the urban-suburban gradients of the Boston, New York, and Washington, D.C. metropolitan areas. In particular we note considerable spatial variation between morning and evening peak periods, both within and between cities, as well as variations in the duration of peak periods, depending on time of year and spatial location. We also examine the relationship between the temporal and spatial structure of morning and evening peak period emissions and the spatial distribution of population and employment density across urban to rural gradients. Finally we utilize data on minute-by-minute vehicle speeds to quantify the effect of traffic congestion on vehicle CO2 emission rates across the Boston metro area, and we highlight the sensitivity of congestion to small sub-hourly variations in traffic flows at key periods of the morning and evening rush hours. Results from our analysis demonstrate the potential for reducing vehicle emissions through time-sensitive toll pricing or commuter incentive schemes targeting peak period vehicle use on urban freeways.

Use of a handheld low-cost sensor to explore the effect of urban design features on local-scale spatial and temporal air quality variability.

PubMed

Miskell, Georgia; Salmond, Jennifer A; Williams, David E

2018-04-01

Portable low-cost instruments have been validated and used to measure ambient nitrogen dioxide (NO 2 ) at multiple sites over a small urban area with 20min time resolution. We use these results combined with land use regression (LUR) and rank correlation methods to explore the effects of traffic, urban design features, and local meteorology and atmosphere chemistry on small-scale spatio-temporal variations. We measured NO 2 at 45 sites around the downtown area of Vancouver, BC, in spring 2016, and constructed four different models: i) a model based on averaging concentrations observed at each site over the whole measurement period, and separate temporal models for ii) morning, iii) midday, and iv) afternoon. Redesign of the temporal models using the average model predictors as constants gave three 'hybrid' models that used both spatial and temporal variables. These accounted for approximately 50% of the total variation with mean absolute error±5ppb. Ranking sites by concentration and by change in concentration across the day showed a shift of high NO 2 concentrations across the central city from morning to afternoon. Locations could be identified in which NO 2 concentration was determined by the geography of the site, and others as ones in which the concentration changed markedly from morning to afternoon indicating the importance of temporal controls. Rank correlation results complemented LUR in identifying significant urban design variables that impacted NO 2 concentration. High variability across a relatively small space was partially described by predictor variables related to traffic (bus stop density, speed limits, traffic counts, distance to traffic lights), atmospheric chemistry (ozone, dew point), and environment (land use, trees). A high-density network recording continuously would be needed fully to capture local variations. Copyright © 2017 Elsevier B.V. All rights reserved.

Phenotypic plasticity to light and nutrient availability alters functional trait ranking across eight perennial grassland species.

PubMed

Siebenkäs, Alrun; Schumacher, Jens; Roscher, Christiane

2015-03-27

Functional traits are often used as species-specific mean trait values in comparative plant ecology or trait-based predictions of ecosystem processes, assuming that interspecific differences are greater than intraspecific trait variation and that trait-based ranking of species is consistent across environments. Although this assumption is increasingly challenged, there is a lack of knowledge regarding to what degree the extent of intraspecific trait variation in response to varying environmental conditions depends on the considered traits and the characteristics of the studied species to evaluate the consequences for trait-based species ranking. We studied functional traits of eight perennial grassland species classified into different functional groups (forbs vs. grasses) and varying in their inherent growth stature (tall vs. small) in a common garden experiment with different environments crossing three levels of nutrient availability and three levels of light availability over 4 months of treatment applications. Grasses and forbs differed in almost all above- and belowground traits, while trait differences related to growth stature were generally small. The traits showing the strongest responses to resource availability were similarly for grasses and forbs those associated with allocation and resource uptake. The strength of trait variation in response to varying resource availability differed among functional groups (grasses > forbs) and species of varying growth stature (small-statured > tall-statured species) in many aboveground traits, but only to a lower extent in belowground traits. These differential responses altered trait-based species ranking in many aboveground traits, such as specific leaf area, tissue nitrogen and carbon concentrations and above-belowground allocation (leaf area ratio and root : shoot ratio) at varying resource supply, while trait-based species ranking was more consistent in belowground traits. Our study shows that species grouping according to functional traits is valid, but trait-based species ranking depends on environmental conditions, thus limiting the applicability of species-specific mean trait values in ecological studies. Published by Oxford University Press on behalf of the Annals of Botany Company.

Geographic variation in the relationship between body mass index and the built environment.

PubMed

Adachi-Mejia, Anna M; Lee, Chanam; Lee, Chunkuen; Carlos, Heather A; Saelens, Brian E; Berke, Ethan M; Doescher, Mark P

2017-07-01

Studies examining associations between weight status and neighborhood built environment (BE) have shown inconsistent results and have generally focused on urban settings. However, many Americans do not live in metropolitan areas and BE impacts may be different outside of metropolitan areas. We sought to examine whether the relationship between body mass index (BMI) and neighborhood BE exists and varies by geographic region across small towns in the United States. We conducted telephone surveys with 2156 adults and geographic information systems data in nine towns located within three geographic regions (Northeast, Texas, Washington) in 2011 and 2012. Multiple regression models examined the relationship between individual BMI and BE measures. Most physical activity variables were significantly associated with lower BMI in all geographic regions. We saw variation across geographic region in the relationship between characteristics of the BE variables and BMI. Some perceived and objectively-measured characteristics of the BE were significantly associated with adult BMI, but significant relationships varied by geographic region. For example, in the Northeast, perceived attractiveness of the neighborhood as a reason for why they chose to live there was associated with lower BMI; in Texas, the perceived presence of a fast food restaurant was negatively associated with BMI; in Washington, perceived presence of trees along the streets was associated with lower BMI. Our findings suggest that regional variation plays a role in the relationship between adult BMI and BE characteristics in small towns. Regardless of geographic location, interventions should encourage utilitarian walking and other forms of physical activity. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of collection geometry variations on linear and circular polarization persistence in both isotropic-scattering and forward-scattering environments

DOE PAGES

van der Laan, John D.; Wright, Jeremy B.; Scrymgeour, David A.; ...

2016-11-04

We present simulation and experimental results showing circular polarization is more tolerant of optical collection geometry (field of view and collection area) variations than linear polarization for forward-scattering environments. Circular polarization also persists superiorly in the forward-scattering environment compared to linear polarization by maintaining its degree of polarization better through increasing optical thicknesses. In contrast, both linear and circular polarizations are susceptible to collection geometry variations for isotropic-scattering (Rayleigh regime) environments, and linear polarization maintains a small advantage in polarization persistence. Simulations and measurements are presented for laboratory-based environments of polystyrene microspheres in water. As a result, particle diameters weremore » 0.0824 μm (for isotropic-scattering) and 1.925 μm (for forward-scattering) with an illumination wavelength of 543.5 nm.« less

Effects of collection geometry variations on linear and circular polarization persistence in both isotropic-scattering and forward-scattering environments

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

van der Laan, John D.; Wright, Jeremy B.; Scrymgeour, David A.

We present simulation and experimental results showing circular polarization is more tolerant of optical collection geometry (field of view and collection area) variations than linear polarization for forward-scattering environments. Circular polarization also persists superiorly in the forward-scattering environment compared to linear polarization by maintaining its degree of polarization better through increasing optical thicknesses. In contrast, both linear and circular polarizations are susceptible to collection geometry variations for isotropic-scattering (Rayleigh regime) environments, and linear polarization maintains a small advantage in polarization persistence. Simulations and measurements are presented for laboratory-based environments of polystyrene microspheres in water. As a result, particle diameters weremore » 0.0824 μm (for isotropic-scattering) and 1.925 μm (for forward-scattering) with an illumination wavelength of 543.5 nm.« less

Fluid mechanics of eating, swallowing and digestion - overview and perspectives.

PubMed

Engmann, Jan; Burbidge, Adam S

2013-02-26

From a very simplistic viewpoint, the human digestive system can be regarded as a long tube (with dramatic variations in diameter, cross-section, wall properties, pumping mechanisms, regulating valves and in-line sensors). We single out a few fluid mechanical phenomena along the trajectory of a food bolus from the mouth to the small intestine and discuss how they influence sensorial perception, safe transport, and nutrient absorption from a bolus. The focus is on lubrication flows between the tongue and palate, the oropharyngeal stage of swallowing and effects of flow on absorption in the small intestine. Specific challenges and opportunities in this research area are highlighted.

Spatial variation in herbicide leaching from a marine clay soil via subsurface drains

PubMed Central

Ulén, Barbro M; Larsbo, Mats; Kreuger, Jenny K; Svanbäck, Annika

2013-01-01

Background Subsurface transport via tile drains can significantly contribute to pesticide contamination of surface waters. The spatial variation in subsurface leaching of normally applied herbicides was examined together with phosphorus losses in 24 experimental plots with water sampled flow-proportionally. The study site was a flat, tile-drained area with 60% marine clay in the topsoil in southeast Sweden. The objectives were to quantify the leaching of frequently used herbicides from a tile drained cracking clay soil and to evaluate the variation in leaching within the experimental area and relate this to topsoil management practices (tillage method and structure liming). Results In summer 2009, 0.14, 0.22 and 1.62%, respectively, of simultaneously applied amounts of MCPA, fluroxypyr and clopyralid were leached by heavy rain five days after spraying. In summer 2011, on average 0.70% of applied bentazone was leached by short bursts of intensive rain 12 days after application. Peak flow concentrations for 50% of the treated area for MCPA and 33% for bentazone exceeded the Swedish no-effect guideline values for aquatic ecosystems. Approximately 0.08% of the glyphosate applied was leached in dissolved form in the winters of 2008/2009 and 2010/2011. Based on measurements of glyphosate in particulate form, total glyphosate losses were twice as high (0.16%) in the second winter. The spatial inter-plot variation was large (72–115%) for all five herbicides studied, despite small variations (25%) in water discharge. Conclusions The study shows the importance of local scale soil transport properties for herbicide leaching in cracking clay soils. © 2013 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:23658148

Trends and geographic patterns in drug-poisoning death rates in the U.S., 1999-2009.

PubMed

Rossen, Lauren M; Khan, Diba; Warner, Margaret

2013-12-01

Drug poisoning mortality has increased substantially in the U.S. over the past 3 decades. Previous studies have described state-level variation and urban-rural differences in drug-poisoning deaths, but variation at the county level has largely not been explored in part because crude county-level death rates are often highly unstable. The goal of the study was to use small-area estimation techniques to produce stable county-level estimates of age-adjusted death rates (AADR) associated with drug poisoning for the U.S., 1999-2009, in order to examine geographic and temporal variation. Population-based observational study using data on 304,087 drug-poisoning deaths in the U.S. from the 1999-2009 National Vital Statistics Multiple Cause of Death Files (analyzed in 2012). Because of the zero-inflated and right-skewed distribution of drug-poisoning death rates, a two-stage modeling procedure was used in which the first stage modeled the probability of observing a death for a given county and year, and the second stage modeled the log-transformed drug-poisoning death rate given that a death occurred. Empirical Bayes estimates of county-level drug-poisoning death rates were mapped to explore temporal and geographic variation. Only 3% of counties had drug-poisoning AADRs greater than ten per 100,000 per year in 1999-2000, compared to 54% in 2008-2009. Drug-poisoning AADRs grew by 394% in rural areas compared to 279% for large central metropolitan counties, but the highest drug-poisoning AADRs were observed in central metropolitan areas from 1999 to 2009. There was substantial geographic variation in drug-poisoning mortality across the U.S. Published by American Journal of Preventive Medicine on behalf of American Journal of Preventive Medicine.

Consistency of Estimated Global Water Cycle Variations Over the Satellite Era

NASA Technical Reports Server (NTRS)

Robertson, F. R.; Bosilovich, M. G.; Roberts, J. B.; Reichle, R. H.; Adler, R.; Ricciardulli, L.; Berg, W.; Huffman, G. J.

2013-01-01

Motivated by the question of whether recent indications of decadal climate variability and a possible "climate shift" may have affected the global water balance, we examine evaporation minus precipitation (E-P) variability integrated over the global oceans and global land from three points of view-remotely sensed retrievals / objective analyses over the oceans, reanalysis vertically-integrated moisture convergence (MFC) over land, and land surface models forced with observations-based precipitation, radiation and near-surface meteorology. Because monthly variations in area-averaged atmospheric moisture storage are small and the global integral of moisture convergence must approach zero, area-integrated E-P over ocean should essentially equal precipitation minus evapotranspiration (P-ET) over land (after adjusting for ocean and land areas). Our analysis reveals considerable uncertainty in the decadal variations of ocean evaporation when integrated to global scales. This is due to differences among datasets in 10m wind speed and near-surface atmospheric specific humidity (2m qa) used in bulk aerodynamic retrievals. Precipitation variations, all relying substantially on passive microwave retrievals over ocean, still have uncertainties in decadal variability, but not to the degree present with ocean evaporation estimates. Reanalysis MFC and P-ET over land from several observationally forced diagnostic and land surface models agree best on interannual variations. However, upward MFC (i.e. P-ET) reanalysis trends are likely related in part to observing system changes affecting atmospheric assimilation models. While some evidence for a low-frequency E-P maximum near 2000 is found, consistent with a recent apparent pause in sea-surface temperature (SST) rise, uncertainties in the datasets used here remain significant. Prospects for further reducing uncertainties are discussed. The results are interpreted in the context of recent climate variability (Pacific Decadal Oscillation, Atlantic Meridional Overturning), and efforts to distinguish these modes from longer-term trends.

Tidal influence through LOD variations on the temporal distribution of earthquake occurrences

NASA Astrophysics Data System (ADS)

Varga, P.; Gambis, D.; Bizouard, Ch.; Bus, Z.; Kiszely, M.

2006-10-01

Stresses generated by the body tides are very small at the depth of crustal earth- quakes (~10^2 N/m2). The maximum value of the lunisolar stress within the depth range of earthquakes is 10^3 N/m2 (at depth of about 600 km). Surface loads, due to oceanic tides, in coastal areas are ~ 104 N/m2. These influences are however too small to affect the outbreak time of seismic events. Authors show the effect on time distribution of seismic activity due to ΔLOD generated by zonal tides for the case of Mf, Mm, Ssa and Sa tidal constituents can be much more effective to trigger earthquakes. According to this approach we show that the tides are not directly triggering the seismic events but through the generated length of day variations. That is the reason why in case of zonal tides a correlation of the lunisolar effect and seismic activity exists, what is not the case for the tesseral and sectorial tides.

Permafrost peatland dynamics during the last millennia in NE European Russia and Finnish Lapland

NASA Astrophysics Data System (ADS)

Zhang, Hui; Väliranta, Minna; Piilo, Sanna; Amesbury, Matthew; Gallego-Sala, Angela; Charman, Dan

2016-04-01

Permafrost peatlands cover vast areas in circum-Arctic regions. Since the 1980s, annual temperatures in these areas have risen by ca. 2 °C and warming is projected to continue. Accordingly, the large carbon store in these peatlands may therefore be threatened. Alternatively, warming may increase productivity more than decomposition and peat accumulation rates may increase. To better understand how high latitude permafrost peatlands have responded to recent warming and what might be their future fate, we carried out detailed studies on two permafrost peatlands in NE Russia and two in Finnish Lapland. Our study methods included high resolution testate amoeba, plant macrofossil, C/N analyses, together with 210Pb and radiocarbon dating. We reconstructed changes in hydrological conditions, plant composition, and peat and carbon accumulation rates. Our preliminary results showed large variations in peat accumulation rates even within a very small area. Furthermore, testate amoeba and plant macrofossil data suggest variations in hydrological conditions during the last millennia. In the future, we will compare our regional data derived from different peatlands to each other, to climate reconstructions and to measured meteorological data.

Trees, chemistry, and prehistory in the American Southwest

USGS Publications Warehouse

Durand, S.R.; Shelley, P.H.; Antweiler, Ronald C.; Taylor, Howard E.

1999-01-01

At least 200 000 trees were used in the building construction in Chaco Canyon, New Mexico, from about (AD) 850-1150. A large portion of these construction timbers were transported 50 km or more and the harvesting location(s) is not known. We argue that a feasible method for determining the wood source areas is to chemically characterize the possible source areas using modern wood and then attempt to match the prehistoric timbers to the modern signatures. This paper establishes the feasibility of this method. ICP-AES was employed to obtain element concentration values for 29 elements, from 62 trees, on three bedrock types. We conclude that it is possible to isolate the variation due to lithology if one controls for wood type (bark, sapwood, heartwood). In addition, ICP-MS was used for the analysis of a small sample of ancient wood. Data from these determinations are presented and the results indicate that the elemental variation is consistent with the most current model of wood use practices in Chaco Canyon. The methods pioneered here should be broadly applicable for determining wood source areas.

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

Peña-Fernández, A.; Lobo-Bedmar, M.C.; González-Muñoz, M.J., E-mail: mariajose.gonzalez@uah.es

Contamination of urban and industrial soils with trace metals has been recognized as a major concern at local, regional and global levels due to their implication on human health. In this study, concentrations of aluminum (Al), arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), tin (Sn), thallium (Tl), vanadium (V) and zinc (Zn) were determined in soil samples collected in Alcalá de Henares (Madrid, Spain) in order to evaluate the annual and seasonal variation in their levels. The results show that the soils of the industrial area have higher metals concentrations than the urbanmore » area. Principal component analysis (PCA) revealed that the two principal sources of trace metal contamination, especially Cd, Cu, Pb, and Zn in the urban soils of Alcalá can be attributed to traffic emissions, while As, Ni and Be primarily originated from industrial discharges. The seasonal variation analysis has revealed that the emission sources in the industrial area remain constant with time. However, in urban areas, both emissions and emission pathways significantly increase over time due to ongoing development. Currently, there is no hypothesis that explains the small seasonal fluctuations of trace metals in soils, since there are many factors affecting this. Owing to the fact that urban environments are becoming the human habitat, it would therefore be advisable to monitor metals and metalloids in urban soils because of the potential risks to human health. - Highlights: • Anthropogenic activities may affect the seasonal metal variation in Alcalá's soils. • Weather characteristics may also influence the seasonal metal variation in soils. • Alcalá's continual urban growth may have increased the levels of metals in its soils. • Metal variability in Alcalá's industrial soils might be dependent on their sources. • High soil metal content might make it difficult to identify temporal variation.« less

[Effect of terracing project on temporal-spatial variation of non-point source pollution load in Hujiashan watershed, China].

PubMed

Han, Qiang; Yu, Xing Xiu; Wang, Wei; Xu, Miao Miao; Ren, Rui; Zhang, Jia Peng

2017-04-18

Taking Hujiashan small watershed as the study area, based on the classified result of Landsat TM/ETM images of 2005, 2010 and 2015, combined with long-term field observation data, and used the export coefficient model, our study explored the effect of small watershed management project on temporal and spatial variation of total nitrogen (TN) load of non-point source pollution under the support of GIS technology. The results indicated that, due to the implementation of slope modification project, the area of cultivated land was significantly increased, while forest and bareland were decreased. The load of non-point source TN increased from 63208 kg in 2005 to 72778 kg in 2010, but reduced to 46876 kg in 2015. The contribution rate from residential areas was higher, the average contribution rate of the three periods was 53.5%, but it showed a decreasing trend year by year. The contribution rate of land use types was 45%, which showed an increasing trend year by year. The contribution rate of livestock was always low. From the spatial distribution, TN loading intensity was changed obviously after the terracing project. High load intensity zone was mainly concentrated on the slope of 5°-15° before terracing project. Nevertheless, high load intensity zone was concentrated on the slope of 15°-35° after terracing project, and 5°-8° had become a low load strength area. The TN load intensity changed little with time on the slope of 0°-8°, and it increased first and then decreased on the slope above 8°. With the treatment of sewage, garbage and livestock manure in rural areas, the output of nitrogen in the living and livestock breeding were significantly reduced. Due to the implementation of the project, the cultivated land area increased by 31%.

Spatially Interpolated Disease Prevalence Estimation Using Collateral Indicators of Morbidity and Ecological Risk

PubMed Central

Congdon, Peter

2013-01-01

This paper considers estimation of disease prevalence for small areas (neighbourhoods) when the available observations on prevalence are for an alternative partition of a region, such as service areas. Interpolation to neighbourhoods uses a kernel method extended to take account of two types of collateral information. The first is morbidity and service use data, such as hospital admissions, observed for neighbourhoods. Variations in morbidity and service use are expected to reflect prevalence. The second type of collateral information is ecological risk factors (e.g., pollution indices) that are expected to explain variability in prevalence in service areas, but are typically observed only for neighbourhoods. An application involves estimating neighbourhood asthma prevalence in a London health region involving 562 neighbourhoods and 189 service (primary care) areas. PMID:24129116

Spatially interpolated disease prevalence estimation using collateral indicators of morbidity and ecological risk.

PubMed

Congdon, Peter

2013-10-14

This paper considers estimation of disease prevalence for small areas (neighbourhoods) when the available observations on prevalence are for an alternative partition of a region, such as service areas. Interpolation to neighbourhoods uses a kernel method extended to take account of two types of collateral information. The first is morbidity and service use data, such as hospital admissions, observed for neighbourhoods. Variations in morbidity and service use are expected to reflect prevalence. The second type of collateral information is ecological risk factors (e.g., pollution indices) that are expected to explain variability in prevalence in service areas, but are typically observed only for neighbourhoods. An application involves estimating neighbourhood asthma prevalence in a London health region involving 562 neighbourhoods and 189 service (primary care) areas.

Small-area Variation in Hypertension Prevalence among Black and White Medicaid Enrollees.

PubMed

White, Kellee; Stewart, John E; Lòpez-DeFede, Ana; Wilkerson, Rebecca C

2016-07-21

To examine within-state geographic heterogeneity in hypertension prevalence and evaluate associations between hypertension prevalence and small-area contextual characteristics for Black and White South Carolina Medicaid enrollees in urban vs rural areas. Ecological. South Carolina, United States. Hypertension prevalence. Data representing adult South Carolina Medicaid recipients enrolled in fiscal year 2013 (N=409,907) and ZIP Code Tabulation Area (ZCTA)-level contextual measures (racial segregation, rurality, poverty, educational attainment, unemployment and primary care physician adequacy) were linked in a spatially referenced database. Optimized Getis-Ord hotspot mapping was used to visualize geographic clustering of hypertension prevalence. Spatial regression was performed to examine the association between hypertension prevalence and small-area contextual indicators. Significant (alpha=.05) hotspot spatial clustering patterns were similar for Blacks and Whites. Black isolation was significantly associated with hypertension among Blacks and Whites in both urban (Black, b=1.34, P<.01; White, b=.66, P<.01) and rural settings (Black, b=.71, P=.02; White, b=.70, P<.01). Primary care physician adequacy was associated with hypertension among urban Blacks (b=-2.14, P<.01) and Whites (b=-1.74, P<.01). The significant geographic overlap of hypertension prevalence hotspots for Black and White Medicaid enrollees provides an opportunity for targeted health intervention. Provider adequacy findings suggest the value of ACA network adequacy standards for Medicaid managed care plans in ensuring health care accessibility for persons with hypertension and related chronic conditions.

Arthropod prey for riparian associated birds in headwater forests of the Oregon Coast Range

USGS Publications Warehouse

Hagar, Joan C.; Li, Judith; Sobota, Janel; Jenkins, Stephanie

2012-01-01

Headwater riparian areas occupy a large proportion of the land base in Pacific Northwest forests, and thus are ecologically and economically important. Although a primary goal of management along small headwater streams is the protection of aquatic resources, streamside habitat also is important for many terrestrial wildlife species. However, mechanisms underlying the riparian associations of some terrestrial species have not been well studied, particularly for headwater drainages. We investigated the diets of and food availability for four bird species associated with riparian habitats in montane coastal forests of western Oregon, USA. We examined variation in the availability of arthropod prey as a function of distance from stream. Specifically, we tested the hypotheses that (1) emergent aquatic insects were a food source for insectivorous birds in headwater riparian areas, and (2) the abundances of aquatic and terrestrial arthropod prey did not differ between streamside and upland areas during the bird breeding season. We found that although adult aquatic insects were available for consumption throughout the study period, they represented a relatively small proportion of available prey abundance and biomass and were present in only 1% of the diet samples from only one of the four riparian-associated bird species. Nonetheless, arthropod prey, comprised primarily of insects of terrestrial origin, was more abundant in streamside than upland samples. We conclude that food resources for birds in headwater riparian areas are primarily associated with terrestrial vegetation, and that bird distributions along the gradient from streamside to upland may be related to variation in arthropod prey availability. Because distinct vegetation may distinguish riparian from upland habitats for riparian-associated birds and their terrestrial arthropod prey, we suggest that understory communities be considered when defining management zones for riparian habitat.

Bumblebees (Bombus terrestris) and honeybees (Apis mellifera) prefer similar colours of higher spectral purity over trained colours.

PubMed

Rohde, Katja; Papiorek, Sarah; Lunau, Klaus

2013-03-01

Differences in the concentration of pigments as well as their composition and spatial arrangement cause intraspecific variation in the spectral signature of flowers. Known colour preferences and requirements for flower-constant foraging bees predict different responses to colour variability. In experimental settings, we simulated small variations of unicoloured petals and variations in the spatial arrangement of colours within tricoloured petals using artificial flowers and studied their impact on the colour choices of bumblebees and honeybees. Workers were trained to artificial flowers of a given colour and then given the simultaneous choice between three test colours: either the training colour, one colour of lower and one of higher spectral purity, or the training colour, one colour of lower and one of higher dominant wavelength; in all cases the perceptual contrast between the training colour and the additional test colours was similarly small. Bees preferred artificial test flowers which resembled the training colour with the exception that they preferred test colours with higher spectral purity over trained colours. Testing the behaviour of bees at artificial flowers displaying a centripetal or centrifugal arrangement of three equally sized colours with small differences in spectral purity, bees did not prefer any type of artificial flowers, but preferentially choose the most spectrally pure area for the first antenna contact at both types of artificial flowers. Our results indicate that innate preferences for flower colours of high spectral purity in pollinators might exert selective pressure on the evolution of flower colours.

Psychological distress among adolescents, and its relationship to individual, family and area characteristics in East London.

PubMed

Fagg, James; Curtis, Sarah; Stansfeld, Stephen; Congdon, Peter

2006-08-01

This paper identifies factors associated with variation in psychosocial distress among adolescents in a relatively deprived and ethnically diverse inner city setting in London, UK. The research draws on literature which discusses whether neighbourhood socio-economic conditions are associated with mental health, as well as attributes of individual adolescents and their families. We report an analysis of data from the Research with East London Adolescents: Community Health Survey (RELACHS). The survey collected data on mental health measured by the Strengths and Difficulties Questionnaire (SDQ), and on various aspects of individual and family circumstances. These data were linked with information about social and economic conditions in 'middle layer standard output areas' (MSOA) used for the population Census 2001, having a mean total population of 6767 in the study area. Census statistics including the Indices of Deprivation for 2004 proposed by the Office of the Deputy Prime Minister, were used to describe the socio-economic conditions within these areas. Although the socio-economic disparities among small areas were not typical of those across the whole of the country, there were differences in levels of deprivation and crime, social fragmentation, and ethnic composition. A Bayesian regression analysis using Gibbs sampling in the programme WinBugs investigated whether there was variability in SDQ at both individual and area (MSOA) level, and whether the predictor variables at both levels were significantly associated with SDQ. Individuals from Asian or Black ethnic groups, and those in families with harmonious relationships and no financial stress had significantly lower SDQ scores, i.e. better health. Those who had special educational needs or long standing illness, or were from reconstituted families had significantly worse SDQ scores. About 6% of the variation in SDQ was associated with area differences. However, this area variation was not related to differences in area indicators of socio-economic deprivation, crime or social fragmentation. There was a complex association between SDQ and ethnic composition of neighbourhoods.

Estimating CHD prevalence by small area: integrating information from health surveys and area mortality.

PubMed

Congdon, Peter

2008-03-01

The risk of coronary heart disease (CHD) is strongly linked both to deprivation and ethnicity and so prevalence will vary considerably between areas. Variations in prevalence are important in assessing health care needs and how far CHD service provision and surgical intervention rates match need. This paper uses a regression model of prevalence rates by age, sex, region and ethnicity from the 1999 and 2003 Health Surveys for England to estimate CHD prevalence for 354 English local authority areas. To allow for the impact of social factors on prevalence, survey information on the deprivation quintile in the respondents' micro-area of residence is also used. Allowance is also made for area CHD mortality rates (obtained from aggregated vital statistics data) which are positively correlated with, and hence a proxy for, CHD prevalence rates. An application involves assessment of surgical intervention rates in relation to prevalence at the level of 28 Strategic Health Authorities.

Ionospheric scintillation by a random phase screen Spectral approach

NASA Technical Reports Server (NTRS)

Rufenach, C. L.

1975-01-01

The theory developed by Briggs and Parkin, given in terms of an anisotropic gaussian correlation function, is extended to a spectral description specified as a continuous function of spatial wavenumber with an intrinsic outer scale as would be expected from a turbulent medium. Two spectral forms were selected for comparison: (1) a power-law variation in wavenumber with a constant three-dimensional index equal to 4, and (2) Gaussian spectral variation. The results are applied to the F-region ionosphere with an outer-scale wavenumber of 2 per km (approximately equal to the Fresnel wavenumber) for the power-law variation, and 0.2 per km for the Gaussian spectral variation. The power-law form with a small outer-scale wavenumber is consistent with recent F-region in-situ measurements, whereas the gaussian form is mathematically convenient and, hence, mostly used in the previous developments before the recent in-situ measurements. Some comparison with microwave scintillation in equatorial areas is made.

A detection method of subrecent to recent tectonic activity in the anticlinal system of the northern Negev, Israel

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

Zilberman, E.; Wachs, D.

Geomorphological and geophysical methods combined with borehole information were employed to search for possible subrecent small-scale vertical movement along the anticlinal fold belt of the central Negev, Israel. Such tectonic deformation might indicate displacement on the buried reverse faults underneath the anticlines. Variations in the thickness of the alluvial fill in the study area, which are in accordance with the fold structures, could be an indication of recent folding activity along the anticlinal system. In order to detect these thickness variations in the alluvial fill, seismic refraction and electrical resistivity measurements were carries out along the valley of Nahal Besor,more » which crosses the anticlinal belt. The thickness variations of the alluvial fill along the valley were not found to indicate any significant tectonic movement along the anticlines during the Pleistocene. The thickest alluvium was found overlying a karst bedrock, hence karst relief is suggested to be responsible for these variations.« less

Diel Variation in Beaked Whale Diving Behavior

DTIC Science & Technology

2008-01-01

While our results are only from a single study area and our sample size is small, diving patterns of these two species appear very stereotypic ...sharks of the genus Isistius (McSweeney et al. 2007). Cookie-cutter sharks are thought to exhibit diel vertical migrations, spending time near the...Mar. Mamm. Sci. 23: 666-687. 17 Mead, J.G. 1989. Beaked whales of the genus Mesoplodon. Pages 349-430 In S.H. Ridgway and R. Harrison

Cerebral ischemia and reperfusion increases the heterogeneity of local oxygen supply/consumption balance.

PubMed

Weiss, Harvey R; Grayson, Jeremy; Liu, Xia; Barsoum, Sylviana; Shah, Harsh; Chi, Oak Z

2013-09-01

After cerebral vessel blockage, local blood flow and O2 consumption becomes lower and oxygen extraction increases. With reperfusion, blood flow is partially restored. We examined the effects of ischemia-reperfusion on the heterogeneity of local venous oxygen saturation in rats in order to determine the pattern of microregional O2 supply/consumption balance in reperfusion. The middle cerebral artery was blocked for 1 hour using the internal carotid approach in 1 group (n=9) and was then reperfused for 2 hours in another group (n=9) of isoflurane-anesthetized rats. Regional cerebral blood flow was determined using a C(14)-iodoantipyrine autoradiographic technique. Regional small vessel arterial and venous oxygen saturations were determined microspectrophotometrically. After 1 hour of ischemia, local cerebral blood flow (92±10 versus 50±10 mL/min per 100 g) and O2 consumption (4.5±0.6 versus 2.7±0.5 mL O2/min per 100 g) decreased compared with the contralateral cortex. Oxygen extraction increased (4.7±0.2 versus 5.4±0.3 mL O2/100 mL) and the variation in small vein (20-60 μm) O2 saturation as determined by its coefficient of variation (=100×SD/mean) increased (5.5 versus 10.5). With 2 hours of reperfusion, the blood flow decrement was reduced and O2 consumption returned to the value in the contralateral cortex. Oxygen extraction remained elevated in the ischemic-reperfused area and the coefficient of variation of small vein O2 saturation increased further (17.3). These data indicated continued reduction of O2 supply/consumption balance with reperfusion. They also demonstrated many small regions of low oxygenation within the reperfused cortical region.

Spatial Variations of Heavy Metals in the Soils of Vegetable-Growing Land along Urban-Rural Gradient of Nanjing, China

PubMed Central

Fang, Shi-Bo; Hu, Hao; Sun, Wan-Chun; Pan, Jian-Jun

2011-01-01

China has experienced rapid urbanization in recent years. The acceleration of urbanization has created wealth and opportunity as well as intensified ecological and environmental problems, especially soil pollution. Our study concentrated on the variation of heavy metal content due to urbanization in the vegetable-growing soil. Laws and other causes of the spatial-temporal variation in heavy metal content of vegetable-growing soils were analyzed for the period of urbanization in Nanjing (the capital of Jiangsu province in China). The levels of Cu, Zn, Pb, Cd and Hg in samples of vegetable-growing soil were detected. The transverse, vertical spatio-temporal variation of heavy metals in soil was analyzed on the base of field investigations and laboratory analysis. The results show that: (1) in soil used for vegetable production, the levels of heavy metals decreased gradually from urban to rural areas; the levels of the main heavy metals in urban areas are significantly higher than suburban and rural areas; (2) the means of the levels of heavy metals, calculated by subtracting the sublayer (15–30 cm) from the toplayer (0–15 cm), are all above zero and large in absolute value in urban areas, but in suburban and rural areas, the means are all above or below zero and small in absolute value. The causes of spatial and temporal variation were analyzed as follows: one cause was associated with mellowness of the soil and the length of time the soil had been used for vegetable production; the other cause was associated with population density and industrial intensity decreasing along the urban to rural gradient (i.e., urbanization levels can explain the distribution of heavy metals in soil to some extent). Land uses should be planned on the basis of heavy metal pollution in soil, especially in urban and suburban regions. Heavily polluted soils have to be expected from food production. Further investigation should be done to determine whether and what kind of agricultural production could be established near urban centers. PMID:21776203

An analytical framework for extracting hydrological information from time series of small reservoirs in a semi-arid region

NASA Astrophysics Data System (ADS)

Annor, Frank; van de Giesen, Nick; Bogaard, Thom; Eilander, Dirk

2013-04-01

Small water reservoirs for water resources management have as important socio-economic advantage that they bring water close to villages and households. This proximity allows for many water uses in addition to irrigation, such as fisheries, household water, building materials (loam, reeds), tourism and recreation, and cattle watering. These positive aspects are offset by the relatively large evaporative losses in comparison to larger reservoirs, although, it is not exactly known how large these losses are. For decision makers, investors and donors, the decision to construct a small reservoir should be multifactored; and based on economic, socio-cultural and environmental factors. For the latter, getting the water balance and the energy budget of small reservoirs right is key for any environmental impact analyses. For Northern Ghana, the relation between volume of a small reservoir and its' surface area has been established in a robust equation as: Volume = 0.00857Area1.4367 with the surface area explaining more than 95% of the variation in water volume of the reservoirs. This allows the use of remote sensing observations for estimating water volume of small reservoirs in northern Ghana. Hydrological analyses of time series of small reservoir areas comprises estimates of evaporation fluxes and cumulative surface runoff curves. Once the reservoirs are full, spillage will occur and volumes and surface areas remain stable at their maximum extents. This implies that the time series of reservoir surface area contains information concerning the on-set of downstream surface runoff. This on-set does not coincide with the on-set of the rainy season but largely depends on the distribution of rainfall events and storage capacity in the subsurface. The main requirement for this analysis is that the reservoir has negligible seepage losses or water influx from the underlying subsurface. In our research, we carried out a time series analysis of surface area extent for about 45 small reservoirs in the Upper East Region of Ghana. Reservoirs without obvious large seepage losses (field survey) were selected. To verify this, stable water isotopic samples are collected from groundwater upstream and downstream from the reservoir. By looking at possible enrichment of downstream groundwater, a good estimate of seepage can be made in addition to estimates on evaporation. We estimated the evaporative losses and compared those with field measurements using eddy correlation measurements. Lastly, we determined the cumulative surface runoff curves for the small reservoirs .We will present this analytical framework for extracting hydrological information from time series of small reservoirs and show the first results for our study region of northern Ghana.

Conservation priorities for endangered Indian tigers through a genomic lens.

PubMed

Natesh, Meghana; Atla, Goutham; Nigam, Parag; Jhala, Yadvendradev V; Zachariah, Arun; Borthakur, Udayan; Ramakrishnan, Uma

2017-08-29

Tigers have lost 93% of their historical range worldwide. India plays a vital role in the conservation of tigers since nearly 60% of all wild tigers are currently found here. However, as protected areas are small (<300 km 2 on average), with only a few individuals in each, many of them may not be independently viable. It is thus important to identify and conserve genetically connected populations, as well as to maintain connectivity within them. We collected samples from wild tigers (Panthera tigris tigris) across India and used genome-wide SNPs to infer genetic connectivity. We genotyped 10,184 SNPs from 38 individuals across 17 protected areas and identified three genetically distinct clusters (corresponding to northwest, southern and central India). The northwest cluster was isolated with low variation and high relatedness. The geographically large central cluster included tigers from central, northeastern and northern India, and had the highest variation. Most genetic diversity (62%) was shared among clusters, while unique variation was highest in the central cluster (8.5%) and lowest in the northwestern one (2%). We did not detect signatures of differential selection or local adaptation. We highlight that the northwest population requires conservation attention to ensure persistence of these tigers.

Leaf-level photosynthetic capacity in lowland Amazonian and high-elevation Andean tropical moist forests of Peru.

PubMed

Bahar, Nur H A; Ishida, F Yoko; Weerasinghe, Lasantha K; Guerrieri, Rossella; O'Sullivan, Odhran S; Bloomfield, Keith J; Asner, Gregory P; Martin, Roberta E; Lloyd, Jon; Malhi, Yadvinder; Phillips, Oliver L; Meir, Patrick; Salinas, Norma; Cosio, Eric G; Domingues, Tomas F; Quesada, Carlos A; Sinca, Felipe; Escudero Vega, Alberto; Zuloaga Ccorimanya, Paola P; Del Aguila-Pasquel, Jhon; Quispe Huaypar, Katherine; Cuba Torres, Israel; Butrón Loayza, Rosalbina; Pelaez Tapia, Yulina; Huaman Ovalle, Judit; Long, Benedict M; Evans, John R; Atkin, Owen K

2017-05-01

We examined whether variations in photosynthetic capacity are linked to variations in the environment and/or associated leaf traits for tropical moist forests (TMFs) in the Andes/western Amazon regions of Peru. We compared photosynthetic capacity (maximal rate of carboxylation of Rubisco (V cmax ), and the maximum rate of electron transport (J max )), leaf mass, nitrogen (N) and phosphorus (P) per unit leaf area (M a , N a and P a , respectively), and chlorophyll from 210 species at 18 field sites along a 3300-m elevation gradient. Western blots were used to quantify the abundance of the CO 2 -fixing enzyme Rubisco. Area- and N-based rates of photosynthetic capacity at 25°C were higher in upland than lowland TMFs, underpinned by greater investment of N in photosynthesis in high-elevation trees. Soil [P] and leaf P a were key explanatory factors for models of area-based V cmax and J max but did not account for variations in photosynthetic N-use efficiency. At any given N a and P a , the fraction of N allocated to photosynthesis was higher in upland than lowland species. For a small subset of lowland TMF trees examined, a substantial fraction of Rubisco was inactive. These results highlight the importance of soil- and leaf-P in defining the photosynthetic capacity of TMFs, with variations in N allocation and Rubisco activation state further influencing photosynthetic rates and N-use efficiency of these critically important forests. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

[Potentials in the regionalization of health indicators using small-area estimation methods : Exemplary results based on the 2009, 2010 and 2012 GEDA studies].

PubMed

Kroll, Lars Eric; Schumann, Maria; Müters, Stephan; Lampert, Thomas

2017-12-01

Nationwide health surveys can be used to estimate regional differences in health. Using traditional estimation techniques, the spatial depth for these estimates is limited due to the constrained sample size. So far - without special refreshment samples - results have only been available for larger populated federal states of Germany. An alternative is regression-based small-area estimation techniques. These models can generate smaller-scale data, but are also subject to greater statistical uncertainties because of the model assumptions. In the present article, exemplary regionalized results based on the studies "Gesundheit in Deutschland aktuell" (GEDA studies) 2009, 2010 and 2012, are compared to the self-rated health status of the respondents. The aim of the article is to analyze the range of regional estimates in order to assess the usefulness of the techniques for health reporting more adequately. The results show that the estimated prevalence is relatively stable when using different samples. Important determinants of the variation of the estimates are the achieved sample size on the district level and the type of the district (cities vs. rural regions). Overall, the present study shows that small-area modeling of prevalence is associated with additional uncertainties compared to conventional estimates, which should be taken into account when interpreting the corresponding findings.

A mesoscale analysis of the pre-storm environment on the 17 June 1986 COHMEX day. [Cooperative Huntsville Meteorological Experiment

NASA Technical Reports Server (NTRS)

Fuelberg, Henry E.; Schudalla, Ronald L.

1989-01-01

The study presented utilized special mesoscale Cooperative Huntsville Meteorological Experiment (COHMEX) data to understand the evolution of the preconvective environment on June 17, 1986. Using the special mesoscale COHMEX data, several mechanisms for triggering the convection are investigated. Afternoon heating probably was a major factor as observed noontime temperatures were near the sounding-derived convection temperatures. The special surface network revealed a quasi-stationary area of convergence not aligned with the front that may be associated with the orography of the area. This study demonstrates that rapid, small scale atmospheric variations preceded convective development on June 17, 1986.

Dust variations in the diffuse interstellar medium: constraints on Milky Way dust from Planck-HFI observations

NASA Astrophysics Data System (ADS)

Ysard, N.; Köhler, M.; Jones, A.; Miville-Deschênes, M.-A.; Abergel, A.; Fanciullo, L.

2015-05-01

Context. The Planck-HFI all-sky survey from 353 to 857 GHz combined with the IRAS data at 100 μm (3000 GHz, IRIS version of the data) show that the dust properties vary from line of sight to line of sight in the diffuse interstellar medium (ISM) at high Galactic latitude (1019 ≤ NH ≤ 2.5 × 1020 H/cm2, for a sky coverage of ~12%). Aims: These observations contradict the usual thinking of uniform dust properties, even in the most diffuse areas of the sky. Thus, our aim is to explain these variations with changes in the ISM properties and with evolution of the grain properties. Methods: Our starting point is the latest core-mantle dust model. This model consists of small aromatic-rich carbon grains, larger amorphous carbonaceous grains with an aliphatic-rich core and an aromatic-rich mantle, and amorphous silicates (mixture of olivine and pyroxene types) with Fe/FeS nano-inclusions covered by aromatic-rich carbon mantles. We explore whether variations in the radiation field or in the gas density distribution in the diffuse ISM could explain the observed variations. The dust properties are also varied in terms of their mantle thickness, metallic nano-inclusions, carbon abundance locked in the grains, and size distributions. Results: We show that variations in the radiation field intensity and gas density distribution cannot explain variations observed with Planck-HFI but that radiation fields harder than the standard ISRF may participate in creating part of the observed variations. We further show that variations in the mantle thickness on the grains coupled with changes in their size distributions can reproduce most of the observations. We concurrently put a limit on the mantle thickness of the silicates, which should not exceed ~ 10 to 15 nm, and find that aromatic-rich mantles are definitely needed for the carbonaceous grain population with a thickness of at least 5 to 7.5 nm. We also find that changes in the carbon cosmic abundance included in the grains could explain part of the variations in dust observations. Finally, we show that varying the composition of metallic nano-inclusions in the silicates cannot account for the variations, at the same time showing that the amount of FeS they contain cannot be > 50% by volume. Conclusions: With small variations in the dust properties, we are able to explain most of the variations in the dust emission observed by Planck-HFI in the diffuse ISM. We also find that the small realistic changes in the dust properties that we consider almost perfectly match the anti-correlation and scatter in the observed β - T relation.

Model of Tooth Morphogenesis Predicts Carabelli Cusp Expression, Size, and Symmetry in Humans

PubMed Central

Hunter, John P.; Guatelli-Steinberg, Debbie; Weston, Theresia C.; Durner, Ryan; Betsinger, Tracy K.

2010-01-01

Background The patterning cascade model of tooth morphogenesis accounts for shape development through the interaction of a small number of genes. In the model, gene expression both directs development and is controlled by the shape of developing teeth. Enamel knots (zones of nonproliferating epithelium) mark the future sites of cusps. In order to form, a new enamel knot must escape the inhibitory fields surrounding other enamel knots before crown components become spatially fixed as morphogenesis ceases. Because cusp location on a fully formed tooth reflects enamel knot placement and tooth size is limited by the cessation of morphogenesis, the model predicts that cusp expression varies with intercusp spacing relative to tooth size. Although previous studies in humans have supported the model's implications, here we directly test the model's predictions for the expression, size, and symmetry of Carabelli cusp, a variation present in many human populations. Methodology/Principal Findings In a dental cast sample of upper first molars (M1s) (187 rights, 189 lefts, and 185 antimeric pairs), we measured tooth area and intercusp distances with a Hirox digital microscope. We assessed Carabelli expression quantitatively as an area in a subsample and qualitatively using two typological schemes in the full sample. As predicted, low relative intercusp distance is associated with Carabelli expression in both right and left samples using either qualitative or quantitative measures. Furthermore, asymmetry in Carabelli area is associated with asymmetry in relative intercusp spacing. Conclusions/Significance These findings support the model's predictions for Carabelli cusp expression both across and within individuals. By comparing right-left pairs of the same individual, our data show that small variations in developmental timing or spacing of enamel knots can influence cusp pattern independently of genotype. Our findings suggest that during evolution new cusps may first appear as a result of small changes in the spacing of enamel knots relative to crown size. PMID:20689576

The association of chromospheric and coronal phenomena with the evolution of the quiet sun magnetic fields

NASA Technical Reports Server (NTRS)

Harvey, Karen L.; Tang, Frances; Gaizauskas, Victor

1986-01-01

Using daily full-disk magnetograms and He I 10830 spectroheliograms to study the count and surface distribution of ephemeral regions over the solar cycle, Harvey (1985) concluded that the small dark structures seen in 10830, thought to correspond to X-ray bright points, were more often associated with magnetic bipoles that appeared to result from an encounter of already existing opposite polarity magentic flux than with emerging small magnetic bipoles (ephemeral regions). Such encounters would be more likely to occur in areas of mixed polarity. The fractional area of the sun covered by mixed polarity fields varies anti-correlated with the solar cycle leading to a possible explanation for the 180 degrees out of phase solar cycle variation of X-ray bright points. To establish the validity of this suggestion, a detailed study of time-sequence magnetic field, He I wavelength 10830, Ha, C IV, and Si II observations of selected areas of the quiet sun was initiated about 2 years ago. The preliminary results of this study are reported.

Using multilevel spatial models to understand salamander site occupancy patterns after wildfire

USGS Publications Warehouse

Chelgren, Nathan; Adams, Michael J.; Bailey, Larissa L.; Bury, R. Bruce

2011-01-01

Studies of the distribution of elusive forest wildlife have suffered from the confounding of true presence with the uncertainty of detection. Occupancy modeling, which incorporates probabilities of species detection conditional on presence, is an emerging approach for reducing observation bias. However, the current likelihood modeling framework is restrictive for handling unexplained sources of variation in the response that may occur when there are dependence structures such as smaller sampling units that are nested within larger sampling units. We used multilevel Bayesian occupancy modeling to handle dependence structures and to partition sources of variation in occupancy of sites by terrestrial salamanders (family Plethodontidae) within and surrounding an earlier wildfire in western Oregon, USA. Comparison of model fit favored a spatial N-mixture model that accounted for variation in salamander abundance over models that were based on binary detection/non-detection data. Though catch per unit effort was higher in burned areas than unburned, there was strong support that this pattern was due to a higher probability of capture for individuals in burned plots. Within the burn, the odds of capturing an individual given it was present were 2.06 times the odds outside the burn, reflecting reduced complexity of ground cover in the burn. There was weak support that true occupancy was lower within the burned area. While the odds of occupancy in the burn were 0.49 times the odds outside the burn among the five species, the magnitude of variation attributed to the burn was small in comparison to variation attributed to other landscape variables and to unexplained, spatially autocorrelated random variation. While ordinary occupancy models may separate the biological pattern of interest from variation in detection probability when all sources of variation are known, the addition of random effects structures for unexplained sources of variation in occupancy and detection probability may often more appropriately represent levels of uncertainty. ?? 2011 by the Ecological Society of America.

Specific surface area of a crushed welded tuff before and after aqueous dissolution

USGS Publications Warehouse

Reddy, M.M.; Claassen, H.C.

1994-01-01

Specific surface areas were measured for several reference minerals (anorthoclase, labradorite and augite), welded tuff and stream sediments from Snowshoe Mountain, near Creede, Colorado. Crushed and sieved tuff had an unexpectedly small variation in specific surface area over a range of size fractions. Replicate surface area measurements of the largest and smallest tuff particle size fractions examined (1-0.3 mm and <0.212 mm) were 2.3 ?? 0.2 m2/g for each size fraction. Reference minerals prepared in the same way as the tuff had smaller specific surface areas than that of the tuff of the same size fraction. Higher than expected tuff specific surface areas appear to be due to porous matrix. Tuff, reacted in solutions with pH values from 2 to 6, had little change in specific surface area in comparison with unreacted tuff. Tuff, reacted with solutions having high acid concentrations (0.1 M hydrochloric acid or sulfuric-hydrofluoric acid), exhibited a marked increase in specific surface area compared to unreacted tuff. ?? 1994.

Best-Matched Internal Standard Normalization in Liquid Chromatography-Mass Spectrometry Metabolomics Applied to Environmental Samples.

PubMed

Boysen, Angela K; Heal, Katherine R; Carlson, Laura T; Ingalls, Anitra E

2018-01-16

The goal of metabolomics is to measure the entire range of small organic molecules in biological samples. In liquid chromatography-mass spectrometry-based metabolomics, formidable analytical challenges remain in removing the nonbiological factors that affect chromatographic peak areas. These factors include sample matrix-induced ion suppression, chromatographic quality, and analytical drift. The combination of these factors is referred to as obscuring variation. Some metabolomics samples can exhibit intense obscuring variation due to matrix-induced ion suppression, rendering large amounts of data unreliable and difficult to interpret. Existing normalization techniques have limited applicability to these sample types. Here we present a data normalization method to minimize the effects of obscuring variation. We normalize peak areas using a batch-specific normalization process, which matches measured metabolites with isotope-labeled internal standards that behave similarly during the analysis. This method, called best-matched internal standard (B-MIS) normalization, can be applied to targeted or untargeted metabolomics data sets and yields relative concentrations. We evaluate and demonstrate the utility of B-MIS normalization using marine environmental samples and laboratory grown cultures of phytoplankton. In untargeted analyses, B-MIS normalization allowed for inclusion of mass features in downstream analyses that would have been considered unreliable without normalization due to obscuring variation. B-MIS normalization for targeted or untargeted metabolomics is freely available at https://github.com/IngallsLabUW/B-MIS-normalization .

Finding hidden periodic signals in time series - an application to stock prices

NASA Astrophysics Data System (ADS)

O'Shea, Michael

2014-03-01

Data in the form of time series appear in many areas of science. In cases where the periodicity is apparent and the only other contribution to the time series is stochastic in origin, the data can be `folded' to improve signal to noise and this has been done for light curves of variable stars with the folding resulting in a cleaner light curve signal. Stock index prices versus time are classic examples of time series. Repeating patterns have been claimed by many workers and include unusually large returns on small-cap stocks during the month of January, and small returns on the Dow Jones Industrial average (DJIA) in the months June through September compared to the rest of the year. Such observations imply that these prices have a periodic component. We investigate this for the DJIA. If such a component exists it is hidden in a large non-periodic variation and a large stochastic variation. We show how to extract this periodic component and for the first time reveal its yearly (averaged) shape. This periodic component leads directly to the `Sell in May and buy at Halloween' adage. We also drill down and show that this yearly variation emerges from approximately half of the underlying stocks making up the DJIA index.

An efficient deterministic-probabilistic approach to modeling regional groundwater flow: 2. Application to Owens Valley, California

USGS Publications Warehouse

Guymon, Gary L.; Yen, Chung-Cheng

1990-01-01

The applicability of a deterministic-probabilistic model for predicting water tables in southern Owens Valley, California, is evaluated. The model is based on a two-layer deterministic model that is cascaded with a two-point probability model. To reduce the potentially large number of uncertain variables in the deterministic model, lumping of uncertain variables was evaluated by sensitivity analysis to reduce the total number of uncertain variables to three variables: hydraulic conductivity, storage coefficient or specific yield, and source-sink function. Results demonstrate that lumping of uncertain parameters reduces computational effort while providing sufficient precision for the case studied. Simulated spatial coefficients of variation for water table temporal position in most of the basin is small, which suggests that deterministic models can predict water tables in these areas with good precision. However, in several important areas where pumping occurs or the geology is complex, the simulated spatial coefficients of variation are over estimated by the two-point probability method.

An efficient deterministic-probabilistic approach to modeling regional groundwater flow: 2. Application to Owens Valley, California

NASA Astrophysics Data System (ADS)

Guymon, Gary L.; Yen, Chung-Cheng

1990-07-01

The applicability of a deterministic-probabilistic model for predicting water tables in southern Owens Valley, California, is evaluated. The model is based on a two-layer deterministic model that is cascaded with a two-point probability model. To reduce the potentially large number of uncertain variables in the deterministic model, lumping of uncertain variables was evaluated by sensitivity analysis to reduce the total number of uncertain variables to three variables: hydraulic conductivity, storage coefficient or specific yield, and source-sink function. Results demonstrate that lumping of uncertain parameters reduces computational effort while providing sufficient precision for the case studied. Simulated spatial coefficients of variation for water table temporal position in most of the basin is small, which suggests that deterministic models can predict water tables in these areas with good precision. However, in several important areas where pumping occurs or the geology is complex, the simulated spatial coefficients of variation are over estimated by the two-point probability method.

A study on modeling nitrogen dioxide concentrations using land-use regression and conventionally used exposure assessment methods

NASA Astrophysics Data System (ADS)

Choi, Giehae; Bell, Michelle L.; Lee, Jong-Tae

2017-04-01

The land-use regression (LUR) approach to estimate the levels of ambient air pollutants is becoming popular due to its high validity in predicting small-area variations. However, only a few studies have been conducted in Asian countries, and much less research has been conducted on comparing the performances and applied estimates of different exposure assessments including LUR. The main objectives of the current study were to conduct nitrogen dioxide (NO2) exposure assessment with four methods including LUR in the Republic of Korea, to compare the model performances, and to estimate the empirical NO2 exposures of a cohort. The study population was defined as the year 2010 participants of a government-supported cohort established for bio-monitoring in Ulsan, Republic of Korea. The annual ambient NO2 exposures of the 969 study participants were estimated with LUR, nearest station, inverse distance weighting, and ordinary kriging. Modeling was based on the annual NO2 average, traffic-related data, land-use data, and altitude of the 13 regularly monitored stations. The final LUR model indicated that area of transportation, distance to residential area, and area of wetland were important predictors of NO2. The LUR model explained 85.8% of the variation observed in the 13 monitoring stations of the year 2009. The LUR model outperformed the others based on leave-one out cross-validation comparing the correlations and root-mean square error. All NO2 estimates ranged from 11.3-18.0 ppb, with that of LUR having the widest range. The NO2 exposure levels of the residents differed by demographics. However, the average was below the national annual guidelines of the Republic of Korea (30 ppb). The LUR models showed high performances in an industrial city in the Republic of Korea, despite the small sample size and limited data. Our findings suggest that the LUR method may be useful in similar settings in Asian countries where the target region is small and availability of data is low.

Calculating Soil Wetness, Evapotranspiration and Carbon Cycle Processes Over Large Grid Areas Using a New Scaling Technique

NASA Technical Reports Server (NTRS)

Sellers, Piers

2012-01-01

Soil wetness typically shows great spatial variability over the length scales of general circulation model (GCM) grid areas (approx 100 km ), and the functions relating evapotranspiration and photosynthetic rate to local-scale (approx 1 m) soil wetness are highly non-linear. Soil respiration is also highly dependent on very small-scale variations in soil wetness. We therefore expect significant inaccuracies whenever we insert a single grid area-average soil wetness value into a function to calculate any of these rates for the grid area. For the particular case of evapotranspiration., this method - use of a grid-averaged soil wetness value - can also provoke severe oscillations in the evapotranspiration rate and soil wetness under some conditions. A method is presented whereby the probability distribution timction(pdf) for soil wetness within a grid area is represented by binning. and numerical integration of the binned pdf is performed to provide a spatially-integrated wetness stress term for the whole grid area, which then permits calculation of grid area fluxes in a single operation. The method is very accurate when 10 or more bins are used, can deal realistically with spatially variable precipitation, conserves moisture exactly and allows for precise modification of the soil wetness pdf after every time step. The method could also be applied to other ecological problems where small-scale processes must be area-integrated, or upscaled, to estimate fluxes over large areas, for example in treatments of the terrestrial carbon budget or trace gas generation.

Proximity to the US-Mexico border: a key to explaining geographic variation in US methamphetamine, cocaine and heroin purity.

PubMed

Cunningham, James K; Maxwell, Jane Carlisle; Campollo, Octavio; Cunningham, Kathryn I; Liu, Lon-Mu; Lin, Hui-Lin

2010-10-01

Although illicit drug purity is a widely discussed health risk, research explaining its geographic variation within a country is rare. This study examines whether proximity to the US-Mexico border, the United States' primary drug import portal, is associated with geographic variation in US methamphetamine, heroin and cocaine purity. Distances (proximity) between the US-Mexico border and locations of methamphetamine, cocaine and heroin seizures/acquisitions (n = 239,070) recorded in STRIDE (System to Retrieve Information from Drug Evidence) were calculated for the period of 1990-2004. The association of drug purity with these distances and other variables, including time and seizure/acquisition size, was examined using hierarchical multivariate linear modeling (HMLM). Coterminous United States. Methamphetamine, cocaine and heroin purity generally decreased with distance from the US-Mexico border. Heroin purity, however, after initially declining with distance, turned upwards-a U-shaped association. During 2000-04, methamphetamine purity also had a U-shaped association with distance. For each of the three drugs, temporal changes in the purity of small acquisitions (<10 g) were typically more dynamic in areas closer to the US-Mexico border. Geographic variance in methamphetamine, cocaine and heroin purity throughout the coterminous United States was associated with US-Mexico border proximity. The U-shaped associations between border-distance and purity for heroin and methamphetamine may be due to imports of those drugs via the eastern United States and southeast Canada, respectively. That said, areas closer to the US-Mexico border generally had relatively high illicit drug purity, as well as more dynamic change in the purity of small ('retail level') drug amounts. © 2010 The Authors, Addiction © 2010 Society for the Study of Addiction.

Exploring Spatial Variability in the Relationship between Long Term Limiting Illness and Area Level Deprivation at the City Level Using Geographically Weighted Regression

PubMed Central

Morrissey, Karyn

2015-01-01

Ecological influences on health outcomes are associated with the spatial stratification of health. However, the majority of studies that seek to understand these ecological influences utilise aspatial methods. Geographically weighted regression (GWR) is a spatial statistics tool that expands standard regression by allowing for spatial variance in parameters. This study contributes to the urban health literature, by employing GWR to uncover geographic variation in Limiting Long Term Illness (LLTI) and area level effects at the small area level in a relatively small, urban environment. Using GWR it was found that each of the three contextual covariates, area level deprivation scores, the percentage of the population aged 75 years plus and the percentage of residences of white ethnicity for each LSOA exhibited a non-stationary relationship with LLTI across space. Multicollinearity among the predictor variables was found not to be a problem. Within an international policy context, this research indicates that even at the city level, a “one-size fits all” policy strategy is not the most appropriate approach to address health outcomes. City “wide” health polices need to be spatially adaptive, based on the contextual characteristics of each area. PMID:29546118

STIR Proposal For Research Area 2.1.2 Surface Energy Balance: Transient Soil Density Impacts Land Surface Characteristics and Characterization

DTIC Science & Technology

2015-12-22

not shown). The relatively small differences were likely associated with differences in surface albedo and longwave radiation from soil surface. Ground...SECURITY CLASSIFICATION OF: Soil density is commonly treated as static in studies on land surface property dynamics. Magnitudes of errors associated...with this assumption are largely unknown. Objectives of this preliminary investigation were to: i) quantify effects of soil density variation on soil

The effect of small variations in profile of airfoils

NASA Technical Reports Server (NTRS)

Ward, Kenneth E

1931-01-01

This report deals with the effect of small variations in ordinates specified by different laboratories for the airfoil section. This study was made in connection with a more general investigation of the effect of small irregularities of the airfoil surface on the aerodynamic characteristics of an airfoil. These tests show that small changes in airfoil contours, resulting from variations in the specified ordinates, have a sufficiently large effect upon the airfoil characteristics to justify the taking of great care in the specification of ordinates for the construction of models.

Examining variations in health within rural Canada.

PubMed

Lavergne, M Ruth; Kephart, George

2012-01-01

Differences in health between urban and rural areas of Canada are well documented. Canadian rural communities are remarkably heterogeneous in terms of social, economic, and geographic characteristics. There is reason to believe that there is also considerable heterogeneity in health within rural Canada but existing literature has not given this adequate consideration. This article describes heterogeneity in health along the urban-rural continuum, both between and within categories of rural areas. Factors that may explain observed variations are then examined. The study population included all adult (>18 years) respondents on the Canadian Community Health Survey Cycle 1.1, linked to census subdivision-level data from the corresponding Canadian Census. Study areas were classified according to Metropolitan Influenced Zones (MIZ), which group rural areas based on their degree of connectivity with nearby urban areas. Dichotomized Health Utilities Index (HUI) scores were the outcome variable. Random-intercept logistic regression models investigated the associations of HUI with individual and area characteristics. To describe between-area variation in health, the proportion of the total variation accounted for by the area random effect (the intra-class correlation coefficient [ICC]) was estimated. To aid interpretation of the magnitude of the effect of area relative to other variables in the models, the ICC was also expressed as a median odds ratio (MOR), or the median amount by which the probability of disability will change for an individual who moves from one area to another. On a descriptive level, poorer health was observed in more remote rural areas, but the size of estimated effects for categories of rural areas was generally small compared with effects of other individual and area variables, and with the degree of heterogeneity between areas. The composition of rural areas is important in order to understand patterns in health. Individual income, education, and employment, and area characteristics such as Francophone or Aboriginal populations, and migration patterns help explain the gradient in health by MIZ, but considerable heterogeneity in health within categories of MIZ remains. In models stratified by MIZ, significant between-area heterogeneity was observed in all models, with MORs ranging from 1.18 to 1.53. It was observed that heterogeneity in health among rural areas is substantial, and generally larger than the effect of rurality, itself, on health. More attention is needed to understand the characteristics of Canada's heterogeneous rural communities, and the different processes by which disparities in health emerge and persist. The findings suggest that a focus on rurality alone, emphasizing urban versus rural disparities, or even continuum-based approaches like MIZ, may be less informative than finding ways to classify and examine different types of rural areas according to factors relevant to health.

The influence of leaf size and shape on leaf thermal dynamics: does theory hold up under natural conditions?

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

Leigh, A.; Sevanto, Sanna Annika; Close, J. D.

Laboratory studies on artificial leaves suggest that leaf thermal dynamics are strongly influenced by the two-dimensional size and shape of leaves and associated boundary layer thickness. Hot environments are therefore said to favour selection for small, narrow or dissected leaves. Empirical evidence from real leaves under field conditions is scant and traditionally based on point measurements that do not capture spatial variation in heat load. Here in this study, we used thermal imagery under field conditions to measure the leaf thermal time constant (τ) in summer and the leaf-to-air temperature difference (ΔT) and temperature range across laminae (T range) duringmore » winter, autumn and summer for 68 Proteaceae species. We investigated the influence of leaf area and margin complexity relative to effective leaf width (w e), the latter being a more direct indicator of boundary layer thickness. Normalized difference of margin complexity had no or weak effects on thermal dynamics, but w e strongly predicted τ and ΔT, whereas leaf area influenced T range. Unlike artificial leaves, however, spatial temperature distribution in large leaves appeared to be governed largely by structural variation. Therefore, we agree that small size, specifically we, has adaptive value in hot environments but not with the idea that thermal regulation is the primary evolutionary driver of leaf dissection.« less

The influence of leaf size and shape on leaf thermal dynamics: does theory hold up under natural conditions?

DOE PAGES

Leigh, A.; Sevanto, Sanna Annika; Close, J. D.; ...

2016-11-05

Laboratory studies on artificial leaves suggest that leaf thermal dynamics are strongly influenced by the two-dimensional size and shape of leaves and associated boundary layer thickness. Hot environments are therefore said to favour selection for small, narrow or dissected leaves. Empirical evidence from real leaves under field conditions is scant and traditionally based on point measurements that do not capture spatial variation in heat load. Here in this study, we used thermal imagery under field conditions to measure the leaf thermal time constant (τ) in summer and the leaf-to-air temperature difference (ΔT) and temperature range across laminae (T range) duringmore » winter, autumn and summer for 68 Proteaceae species. We investigated the influence of leaf area and margin complexity relative to effective leaf width (w e), the latter being a more direct indicator of boundary layer thickness. Normalized difference of margin complexity had no or weak effects on thermal dynamics, but w e strongly predicted τ and ΔT, whereas leaf area influenced T range. Unlike artificial leaves, however, spatial temperature distribution in large leaves appeared to be governed largely by structural variation. Therefore, we agree that small size, specifically we, has adaptive value in hot environments but not with the idea that thermal regulation is the primary evolutionary driver of leaf dissection.« less

Area-variable capacitive microaccelerometer with force-balancing electrodes

NASA Astrophysics Data System (ADS)

Ha, Byeoungju; Lee, Byeungleul; Sung, Sangkyung; Choi, Sangon; Shinn, Meenam; Oh, Yong-Soo; Song, Ci M.

1997-11-01

A surface micromachined accelerometer which senses an inertial motion with an area variation and a force balancing electrodes is developed. The grid-type planar mass of a 7 micrometers thick polysilicon is supported by four thin beams and suspended above a silicon substrate with a 1.5 micrometers air gap. The motion sensing electrodes are formed on the substrate. The sensor is designed as an interdigital rib structure that has a differential capacitor arrangement. The moveable electrodes are mounted on the mass and the pairs of the stationary electrodes are patterned on the substrate. In the accelerometer that has comb-type movable electrodes, the mechanical stress and the electrical pulling effects between a moveable electrodes and the fixed electrodes occur. However this grid-type structure can have a large area variation in a small area relatively without stress and pulling, high sensitivity can be achieved. In order to improve the dynamic rang and a linearity, a pair of comb shape force-balancing electrodes are implemented on both sides of the mass. The force-balancing electrodes are made of the same layer as the mass and anchored on a silicon substrate. When acceleration is applied in the lateral direction, the difference of capacitance results from the area variation between the two capacitors and is measured using a charge amplifier. As AC coupled complimentary pick- off signals are applied in paris of stationary electrodes, the undesirable effects due to temperature and electrical noise are reduced effectively. The accelerometer has a sensitivity of 28mV/g and a bandwidth of DC-120Hz. A resolution of 3mg and a non-linearity of 1.3 percent is achieved for a measurement range of +/- 9 g.

Characterization of shallow groundwater quality in the Lower St. Johns River Basin: a case study.

PubMed

Ouyang, Ying; Zhang, Jia-En; Parajuli, Prem

2013-12-01

Characterization of groundwater quality allows the evaluation of groundwater pollution and provides information for better management of groundwater resources. This study characterized the shallow groundwater quality and its spatial and seasonal variations in the Lower St. Johns River Basin, Florida, USA, under agricultural, forest, wastewater, and residential land uses using field measurements and two-dimensional kriging analysis. Comparison of the concentrations of groundwater quality constituents against the US EPA's water quality criteria showed that the maximum nitrate/nitrite (NO x ) and arsenic (As) concentrations exceeded the EPA's drinking water standard limits, while the maximum Cl, SO 4 (2-) , and Mn concentrations exceeded the EPA's national secondary drinking water regulations. In general, high kriging estimated groundwater NH 4 (+) concentrations were found around the agricultural areas, while high kriging estimated groundwater NO x concentrations were observed in the residential areas with a high density of septic tank distribution. Our study further revealed that more areas were found with high estimated NO x concentrations in summer than in spring. This occurred partially because of more NO x leaching into the shallow groundwater due to the wetter summer and partially because of faster nitrification rate due to the higher temperature in summer. Large extent and high kriging estimated total phosphorus concentrations were found in the residential areas. Overall, the groundwater Na and Mg concentration distributions were relatively more even in summer than in spring. Higher kriging estimated groundwater As concentrations were found around the agricultural areas, which exceeded the EPA's drinking water standard limit. Very small variations in groundwater dissolved organic carbon concentrations were observed between spring and summer. This study demonstrated that the concentrations of groundwater quality constituents varied from location to location, and impacts of land uses on groundwater quality variation were profound.

School Segregation and Disparities in Urban, Suburban, and Rural Areas

PubMed Central

Logan, John R.; Burdick-Will, Julia

2018-01-01

Much of the literature on racial and ethnic educational inequality focuses on the contrast between Black and Hispanic students in urban areas and white suburban students. This study extends past research on school segregation and racial/ethnic disparities by highlighting the importance of rural areas and regional variation. Although schools in rural America are disproportionately white, they nevertheless are like urban schools, and disadvantaged relative to suburban schools, in terms of poverty and test performance. The group most affected by rural school disadvantage is Native Americans, who are a small share of students nationally but much more prominent and highly disadvantaged in rural areas, particularly in some parts of the country. These figures suggest a strong case for including rural schools in the continuing conversation about how to deal with unfairness in public education. PMID:29430018

Spatial and spectral simulation of LANDSAT images of agricultural areas

NASA Technical Reports Server (NTRS)

Pont, W. F., Jr. (Principal Investigator)

1982-01-01

A LANDSAT scene simulation capability was developed to study the effects of small fields and misregistration on LANDSAT-based crop proportion estimation procedures. The simulation employs a pattern of ground polygons each with a crop ID, planting date, and scale factor. Historical greenness/brightness crop development profiles generate the mean signal values for each polygon. Historical within-field covariances add texture to pixels in each polygon. The planting dates and scale factors create between-field/within-crop variation. Between field and crop variation is achieved by the above and crop profile differences. The LANDSAT point spread function is used to add correlation between nearby pixels. The next effect of the point spread function is to blur the image. Mixed pixels and misregistration are also simulated.

Avoidable hospitalizations in Switzerland: a small area analysis on regional variation, density of physicians, hospital supply and rurality.

PubMed

Berlin, Claudia; Busato, André; Rosemann, Thomas; Djalali, Sima; Maessen, Maud

2014-07-03

Avoidable hospitalizations (AH) are hospital admissions for diseases and conditions that could have been prevented by appropriate ambulatory care. We examine regional variation of AH in Switzerland and the factors that determine AH. We used hospital service areas, and data from 2008-2010 hospital discharges in Switzerland to examine regional variation in AH. Age and sex standardized AH were the outcome variable, and year of admission, primary care physician density, medical specialist density, rurality, hospital bed density and type of hospital reimbursement system were explanatory variables in our multilevel poisson regression. Regional differences in AH were as high as 12-fold. Poisson regression showed significant increase of all AH over time. There was a significantly lower rate of all AH in areas with more primary care physicians. Rates increased in areas with more specialists. Rates of all AH also increased where the proportion of residences in rural communities increased. Regional hospital capacity and type of hospital reimbursement did not have significant associations. Inconsistent patterns of significant determinants were found for disease specific analyses. The identification of regions with high and low AH rates is a starting point for future studies on unwarranted medical procedures, and may help to reduce their incidence. AH have complex multifactorial origins and this study demonstrates that rurality and physician density are relevant determinants. The results are helpful to improve the performance of the outpatient sector with emphasis on local context. Rural and urban differences in health care delivery remain a cause of concern in Switzerland.

Experimental determination of the PTW 60019 microDiamond dosimeter active area and volume

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

Marinelli, Marco, E-mail: marco.marinelli@uniroma2

Purpose: Small field output correction factors have been studied by several research groups for the PTW 60019 microDiamond (MD) dosimeter, by comparing the response of such a device with both reference dosimeters and Monte Carlo simulations. A general good agreement is observed for field sizes down to about 1 cm. However, evident inconsistencies can be noticed when comparing some experimental results and Monte Carlo simulations obtained for smaller irradiation fields. This issue was tentatively attributed by some authors to unintentional large variations of the MD active surface area. The aim of the present study is a nondestructive experimental determination ofmore » the MD active surface area and active volume. Methods: Ten MD dosimeters, one MD prototype, and three synthetic diamond samples were investigated in the present work. 2D maps of the MD response were recorded under scanned soft x-ray microbeam irradiation, leading to an experimental determination of the device active surface area. Profiles of the device responses were measured as well. In order to evaluate the MD active volume, the thickness of the diamond sensing layer was independently evaluated by capacitance measurements and alpha particle detection experiments. The MD sensitivity, measured at the PTW calibration laboratory, was also used to calculate the device active volume thickness. Results: An average active surface area diameter of (2.19 ± 0.02) mm was evaluated by 2D maps and response profiles of all the MDs. Average active volume thicknesses of (1.01 ± 0.13) μm and (0.97 ± 0.14) μm were derived by capacitance and sensitivity measurements, respectively. The obtained results are well in agreement with the nominal values reported in the manufacturer dosimeter specifications. A homogeneous response was observed over the whole device active area. Besides the one from the device active volume, no contributions from other components of the housing nor from encapsulation materials were observed in the 2D response maps. Conclusions: The obtained results demonstrate the high reproducibility of the MD fabrication process. The observed discrepancies among the output correction factors reported by several authors for MD response in very small fields are very unlikely to be ascribed to unintentional variations of the device active surface area and volume. It is the opinion of the authors that the role of the volume averaging as well as of other perturbation effects should be separately investigated instead, both experimentally and by Monte Carlo simulations, in order to better clarify the behaviour of the MD response in very small fields.« less

Evolution of the central sulcus morphology in primates.

PubMed

Hopkins, William D; Meguerditchian, Adrien; Coulon, Olivier; Bogart, Stephanie; Mangin, Jean-François; Sherwood, Chet C; Grabowski, Mark W; Bennett, Allyson J; Pierre, Peter J; Fears, Scott; Woods, Roger; Hof, Patrick R; Vauclair, Jacques

2014-01-01

The central sulcus (CS) divides the pre- and postcentral gyri along the dorsal-ventral plane of which all motor and sensory functions are topographically organized. The motor-hand area of the precentral gyrus or KNOB has been described as the anatomical substrate of the hand in humans. Given the importance of the hand in primate evolution, here we examine the evolution of the motor-hand area by comparing the relative size and pattern of cortical folding of the CS surface area from magnetic resonance images in 131 primates, including Old World monkeys, apes and humans. We found that humans and great apes have a well-formed motor-hand area that can be seen in the variation in depth of the CS along the dorsal-ventral plane. We further found that great apes have relatively large CS surface areas compared to Old World monkeys. However, relative to great apes, humans have a small motor-hand area in terms of both adjusted and absolute surface areas. © 2014 S. Karger AG, Basel.

Anatomical and morphological study of the subcoracoacromial canal.

PubMed

Le Reun, O; Lebhar, J; Mateos, F; Voisin, J L; Thomazeau, H; Ropars, M

2016-12-01

Many clinical anatomy studies have looked into how variations in the acromion, coracoacromial ligament (CAL) and subacromial space are associated with rotator cuff injuries. However, no study up to now had defined anatomically the fibro-osseous canal that confines the supraspinatus muscle in the subcoracoacromial space. Through an anatomical study of the scapula, we defined the bone-related parameters of this canal and its anatomical variations. This study on dry bones involved 71 scapulas. With standardised photographs in two orthogonal views (superior and lateral), the surface area of the subcoracoacromial canal and the anatomical parameters making up this canal were defined and measured using image analysis software. The primary analysis evaluated the anatomical parameters of the canal as a function of three canal surface area groups; the secondary analysis looked into how variations in the canal surface area were related to the type of acromion according to the Bigliani classification. Relative to glenoid width, the group with a large canal surface area (L) had significantly less lateral overhang of the acromion than the group with a small canal surface area (S), with ratios of 0.41±0.23 and 0.58±0.3, respectively (P=0.04). The mean length of the CAL was 46±8mm in the L group and 39±9mm in the S group (P=0.003). The coracoacromial arch angle was 38°±11° in the L group and 34°±9° in the S group; the canal surface area was smaller in specimens with a smaller coracoacromial arch angle (P=0.20). Apart from acromial morphology, there could be innate anatomical features of the scapula that predispose people to extrinsic lesions to the supraspinatus tendon (lateral overhang, coracoacromial arch angle) by reducing the subcoracoacromial canal's surface area. Anatomical descriptive study. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

How do microlocal environmental variations affect microbial activities of a Pinus halepensis litter in a Mediterranean coastal area?

PubMed

Qasemian, Leila; Guiral, Daniel; Farnet, Anne-Marie

2014-10-15

Mediterranean coastal ecosystems suffer many different types of natural and anthropogenic environmental pressure. Microbial communities, major conductors of organic matter decomposition are also subject to these environmental constraints. In this study, our aim was to understand how microbial activities vary at a small spatio-temporal scale in a Mediterranean coastal environment. Microbial activities were monitored in a Pinus halepensis litter collected from two areas, one close to (10 m) and one far from (300 m) the French Mediterranean coast. Litters were transferred from one area to the other using litterbags and studied via different microbial indicators after 2, 5 and 13 months. Microbial Basal Respiration, qCO₂, certain enzyme activities (laccase, cellulase, β-glucosidase and acid phosphatase) and functional diversity via Biolog microplates were assayed in litterbags left in the area of origin as well as in litterbags transferred from one area to the other. Results highlight that microbial activities differ significantly in this short spatial scale over time. The influence of microlocal conditions more intensified for litters situated close to the sea, especially during summer seems to have a stressful effect on microbial communities, leading to less efficient functional activities. However, microbial activities were more strongly influenced by temporal variations linked to seasonality than by location. Copyright © 2014 Elsevier B.V. All rights reserved.

Spatio-temporal patterns and environmental controls of small pelagic fish body condition from contrasted Mediterranean areas

NASA Astrophysics Data System (ADS)

Brosset, Pablo; Fromentin, Jean-Marc; Van Beveren, Elisabeth; Lloret, Josep; Marques, Virginie; Basilone, Gualtiero; Bonanno, Angelo; Carpi, Piera; Donato, Fortunata; Čikeš Keč, Vanja; De Felice, Andrea; Ferreri, Rosalia; Gašparević, Denis; Giráldez, Ana; Gücü, Ali; Iglesias, Magdalena; Leonori, Iole; Palomera, Isabel; Somarakis, Stylianos; Tičina, Vjekoslav; Torres, Pedro; Ventero, Ana; Zorica, Barbara; Ménard, Frédéric; Saraux, Claire

2017-02-01

Small pelagic fish are among the most ecologically and economically important marine fish species and are characterized by large fluctuations all over the world. In the Mediterranean Sea, low catches and biomass of anchovies and sardines have been described in some areas during the last decade, resulting in important fisheries crises. Therefore, we studied anchovy and sardine body condition variability, a key index of population health and its response to environmental and anthropogenic changes. Wide temporal and spatial patterns were investigated by analyzing separately data from scientific surveys and fisheries in eight Mediterranean areas between 1975 and 2015. Results showed that anchovy and sardine body condition as well as maximum size in some areas sharply decreased in most Mediterranean areas along years (except in the Northern Alboran Sea). Despite this general pattern, well-marked environmental differences between sub-regions were highlighted by several analyses and variations in body condition were not found to be homogeneous over all the Mediterranean Sea. Further, other analyses revealed that except for the Adriatic where major changes towards a lower body condition were concomitant with a decrease in river runoffs and chl-a concentration, no concomitant environmental regime shift was detected in other areas. Together, these analyses highlighted the current poor body condition of almost all small pelagic fish populations in the Mediterranean. Yet, global environmental indices could not explain the observed changes and the general decrease in condition might more likely come from regional environmental and/or anthropogenic (fishing) effects. A prolonged state of poor fish body condition, together with an observed reduced size and early age-at-maturity may have strong ecological, economic and social consequences all around the Mediterranean Sea.

Living on the edge: conservation genetics of seven thermophilous plant species in a high Arctic archipelago

PubMed Central

Brysting, Anne Krag; Elven, Reidar; Alsos, Inger Greve

2017-01-01

Abstract Small, isolated and/or peripheral populations are expected to harbour low levels of genetic variation and may therefore have reduced adaptability to environmental change, including climate warming. In the Arctic, global warming has already caused vegetation change across the region and is acting as a significant stressor on Arctic biodiversity. Many of the rare plants in the Arctic are relicts from early Holocene warm periods, but their ability to benefit from the current warming is dependent on the viability of their populations. We therefore examined Amplified Fragment Length Polymorphism (AFLP) data from regional red listed vascular plant species in the High Arctic archipelago of Svalbard and reference populations from the main distribution area of: (1) Botrychium lunaria, (2) Carex capillaris ssp. fuscidula, (3) Comastoma tenellum, (4) Kobresia simpliciuscula ssp. subholarctica, (5) Ranunculus wilanderi, (6) Sibbaldia procumbens and (7) Tofieldia pusilla. In addition, we gathered population size data in Svalbard. The Svalbard populations had low genetic diversity and distinctiveness and few or no private markers compared to populations outside the archipelago. This is similar to observations in other rare species in Svalbard and the genetic depletion may be due to an initial founder effect and/or a genetic bottleneck caused by late Holocene cooling. There seems to be limited gene flow from other areas and the Svalbard populations should therefore be considered as demographically independent management units. Overall, these management units have small and/or few populations and are therefore prone to stochastic events which may further increase vulnerability to inbreeding depression, loss of genetic variation, and reduced evolutionary potential. Our results support theory predicting lower levels of genetic diversity in small, isolated and/or peripheral populations and may be of importance for management of other rare plant species in the Arctic. PMID:28108432

Influence of hydroclimatic variations on solute concentration dynamics in nested subtropical catchments with heterogeneous landscapes.

PubMed

Piazza, Gustavo Antonio; Dupas, Rémi; Gascuel-Odoux, Chantal; Grimaldi, Catherine; Pinheiro, Adilson; Kaufmann, Vander

2018-04-20

Despite global efforts to monitor water quality in catchments worldwide, tropical and subtropical zones still lack data to study the influence of human activities and climate variations on solute dynamics. In this study, we monitored ten solutes every two weeks for six years (2010-2015) in three nested catchments (2 to30 km 2 ), which contained heterogeneous landscapes composed of forests and agricultural land, and one small neighboring forested catchment (0.4 km 2 ). Data analysis revealed that i) rainfall, discharge and solute concentrations displayed no clear seasonal patterns, unlike many catchments of the temperate zone; ii) solute concentrations in the agricultural area were higher than those in the forested area, but both areas displayed similar temporal patterns due to a common hydroclimatic driver; iii) all four catchments displayed a chemostatic export regime for most of the solutes, similar to catchments of the temperate zone; and iv) a positive correlation was observed between anion concentrations and ENSO (El Niño-Southern Oscillation) index. ENSO appeared to influence both hydroclimatic and anion dynamics in these subtropical catchments. Copyright © 2018 Elsevier B.V. All rights reserved.

Inverse problem and variation method to optimize cascade heat exchange network in central heating system

NASA Astrophysics Data System (ADS)

Zhang, Yin; Wei, Zhiyuan; Zhang, Yinping; Wang, Xin

2017-12-01

Urban heating in northern China accounts for 40% of total building energy usage. In central heating systems, heat is often transferred from heat source to users by the heat network where several heat exchangers are installed at heat source, substations and terminals respectively. For given overall heating capacity and heat source temperature, increasing the terminal fluid temperature is an effective way to improve the thermal performance of such cascade heat exchange network for energy saving. In this paper, the mathematical optimization model of the cascade heat exchange network with three-stage heat exchangers in series is established. Aim at maximizing the cold fluid temperature for given hot fluid temperature and overall heating capacity, the optimal heat exchange area distribution and the medium fluids' flow rates are determined through inverse problem and variation method. The preliminary results show that the heat exchange areas should be distributed equally for each heat exchanger. It also indicates that in order to improve the thermal performance of the whole system, more heat exchange areas should be allocated to the heat exchanger where flow rate difference between two fluids is relatively small. This work is important for guiding the optimization design of practical cascade heating systems.

A possible effect of electromagnetic radiation from mobile phone base stations on the number of breeding house sparrows (Passer domesticus).

PubMed

Everaert, Joris; Bauwens, Dirk

2007-01-01

A possible effect of long-term exposure to low-intensity electromagnetic radiation from mobile phone (GSM) base stations on the number of House Sparrows during the breeding season was studied in six residential districts in Belgium. We sampled 150 point locations within the 6 areas to examine small-scale geographic variation in the number of House Sparrow males and the strength of electromagnetic radiation from base stations. Spatial variation in the number of House Sparrow males was negatively and highly significantly related to the strength of electric fields from both the 900 and 1800 MHz downlink frequency bands and from the sum of these bands (Chi(2)-tests and AIC-criteria, P<0.001). This negative relationship was highly similar within each of the six study areas, despite differences among areas in both the number of birds and radiation levels. Thus, our data show that fewer House Sparrow males were seen at locations with relatively high electric field strength values of GSM base stations and therefore support the notion that long-term exposure to higher levels of radiation negatively affects the abundance or behavior of House Sparrows in the wild.

Geology of an area near Brentwood, Williamson County, Tennessee

USGS Publications Warehouse

Hanchar, D.W.

1988-01-01

The geology and structure of an area near Brentwood, Williamson County, Tennessee, were studied to define the potential aquifers and confining units that comprise the groundwater flow system of the area. Four different formations were identified. These formations are, in descending order, the Bigby-Cannon Limestone, the Hermitage Formation, the Carters Limestone, and the Lebanon Limestone. The Bigby-Cannon Limestone and the Hermitage Formation have been affected by recent erosion. Any variation of the Carters Limestone is controlled by pre-Carters erosion of the top of the Lebanon Limestone. The thickness of this formation ranges from 65 to 79 ft. A small scale anticline-syncline pair is evident. This structure is not a result of erosion and also occurs in the T-3 bentonite bed in the Carters Limestone. (USGS)

Small Scale Biodiversity of an Alkaline Hot Spring in Yellowstone National Park

NASA Astrophysics Data System (ADS)

Walther, K.; Oiler, J.; Meyer-Dombard, D. R.

2012-12-01

To date, many phylogenetic diversity studies have been conducted in Yellowstone National Park (YNP) [1-7] focusing on the amplification of the 16S rRNA gene and "metagenomic" datasets. However, few reports focus on diversity at small scales. Here, we report on a small scale biodiversity study of sediment and biofilm communities within a confined area of a YNP hot spring, compare and contrast these communities to other sediment and biofilm communities from previous studies [1-7], and with other sediment and biofilm communities in the same system. Sediment and biofilm samples were collected, using a 30 x 50 cm sampling grid divided in 5 x 5 cm squares, which was placed in the outflow channel of "Bat Pool", an alkaline (pH 7.9) hot spring in YNP. Accompanying geochemical data included a full range of spectrophotometry measurements along with major ions, trace elements, and DIC/DOC. In addition, in situ temperature and conductivity arrays were placed within the grid location. The temperature array closest to the source varied between 83-88°C, while the temperature array 40 cm downstream varied between ~83.5-86.5°C. The two conductivity arrays yielded measurements of 5632 μS and 5710 μS showing little variation within the sampling area. Within the grid space, DO ranged from 0.5-1.33 mg/L, with relatively similar, but slightly lower values down the outflow channel. Sulfide values within the grid ranged from 1020-1671 μg/L, while sulfide values outside of the grid region fluctuated, but generally followed the trend of decreasing from source down the outflow. Despite the relative heterogeneity of chemical and physical parameters in the grid space, there was biological diversity in sediments and biofilms at the 5 cm scale. Small scale biodiversity was analyzed by selecting a representative number of samples from within the grid. DNA was extracted and variable regions V3 and V6 (Archaea and Bacteria, respectively) were sequenced with 454 pyrosequencing. The datasets from each of the samples were randomly subsampled and the same number of sequences was taken from each dataset so that the samples could be directly compared. Using the Ribosomal Database Project Pyrosequencing Pipeline (http://rdp.cme.msu.edu/), the sequences were aligned, complete linkage clustering was performed, Shannon and Chao1 indices were calculated, and rarefaction curves were made. The RDP Classifier tool afforded classification in a taxonomical hierarchy and the samples were compared on the order level to determine the variation of the microbial communities within the sampling grid. Additional alpha and beta diversity indices were also established. Through comparing the samples on the order level, it was determined that there is variation within a small sampling area despite similar geochemical and temperature conditions at the time of sampling. This variation is seen in both the sediment and biofilm communities, primarily seen among Bacteria. [1] Barns, S.M. et al. (1994) PNAS. 91: 1609-1613. [2] Barns, S.M. et al. (1996) PNAS. 93: 9188-9193. [3] Hall, J.R. et al. (2008) AEM. 74(15): 4910-4922. [4] Hugenholtz, P. et al. (1998) JofBac. 180(2): 366-376. [5] Meyer-Dombard, D. R. et al. (2005) Geobio. 3: 211-227. [6] Meyer-Dombard, D.R. et al. (2011) EM. 13(8): 2216-2231. [7] Reysenbach, A.L. et al. (1994) AEM. 60 (6): 2113-2119.

Comparison of Plains Volcanism in the Tempe Terra Region of Mars to the Eastern Snake River Plains, Idaho with Implications for Geochemical Constraints

NASA Technical Reports Server (NTRS)

Weren, S. L.; Sakimoto, S. E. H.; Hughes, S. S.; Gregg, T. K. P.

2004-01-01

The Eastern Snake River Plains (ESRP) in Idaho have long been considered a terrestrial analog for the plains volcanism like that evident in Syria Planum and Tempe Terra, Mars. Both the ESRP and Tempe Terra are sediment-blanketed volcanic fields in areas with significant extensional faulting. Similar volcanic features can be observed throughout both study areas using field analysis and DEMs of the ESRP and the Mars Global Surveyor (MGS) data from Mars. These features include flow fields, low shields, shields with steep summits, and fissure eruptions. A few other volcanic features, such as cinder cones, which suggest variable compositions, volatile interactions, and multiple volcanic events can be seen in both areas. The eruptions in both the ESRP and Tempe Terra generally originate from the fissures creating elongate, multi-vent shields as well as isolated or aligned single vent shields. Many of these show evidence of radial flow patterns from summit craters as well as lava tube fed flows. The volcanoes of Tempe Terra display some of the global latitudinal parameter trends of small volcanoes on Mars. Some of these trends may be explained by the variation of volatile content and compositional variation across Mars. However, within Tempe Terra no significant local latitudinal trends can be seen in edifice attributes and not all variations are explained by global trends. This study builds upon previous studies of the Tempe Terra region and the ESRP in order to develop a more detailed representation of features and topographic data. Using these data we attempt to help constrain the composition and eruptive style of the Tempe Terra volcanoes by correlating them with the similar and quantified ESRP variations.

Investigation of Surface Phenomena in Shocked Tin in Converging Geometry

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

Rousculp, Christopher L.; Oro, David Michael; Griego, Jeffrey Randall

2016-04-14

There is a great interest in RMI as source of ejecta from metal shells. Previous experiments have explored wavelength amplitude (kA) variation but they have a small range of drive pressures and are in planer geometry. Simulations, both MD and hydro, have explored RMI in planer geometry. The ejecta source model from RMI is an area of active algorithm and code development in ASCI-IC Lagrangian Applications Project. PHELIX offers precise, reproducible variable driver for Hydro and material physics diagnoses with proton radiography.

Deployment and retraction of a cable-driven solar array: Testing and simulation

NASA Technical Reports Server (NTRS)

Kumar, P.; Pellegrino, S.

1995-01-01

The paper investigates three critical areas in cable-driven rigid-panel solar arrays: First, the variation of deployment and retraction cable tensions due to friction at the hinges; Second, the change in deployment dynamics associated with different deployment histories; Third, the relationship between the level of pre-tension in the closed contact loops and the synchronization of deployment. A small scale model array has been made and tested, and its behavior has been compared to numerical simulations.

Identifying areas at risk of low birth weight using spatial epidemiology: A small area surveillance study.

PubMed

Insaf, Tabassum Z; Talbot, Thomas

2016-07-01

To assess the geographic distribution of Low Birth Weight (LBW) in New York State among singleton births using a spatial regression approach in order to identify priority areas for public health actions. LBW was defined as birth weight less than 2500g. Geocoded data from 562,586 birth certificates in New York State (years 2008-2012) were merged with 2010 census data at the tract level. To provide stable estimates and maintain confidentiality, data were aggregated to yield 1268 areas of analysis. LBW prevalence among singleton births was related with area-level behavioral, socioeconomic and demographic characteristics using a Poisson mixed effects spatial error regression model. Observed low birth weight showed statistically significant auto-correlation in our study area (Moran's I 0.16 p value 0.0005). After over-dispersion correction and accounting for fixed effects for selected social determinants, spatial autocorrelation was fully accounted for (Moran's I-0.007 p value 0.241). The proportion of LBW was higher in areas with larger Hispanic or Black populations and high smoking prevalence. Smoothed maps with predicted prevalence were developed to identify areas at high risk of LBW. Spatial patterns of residual variation were analyzed to identify unique risk factors. Neighborhood racial composition contributes to disparities in LBW prevalence beyond differences in behavioral and socioeconomic factors. Small-area analyses of LBW can identify areas for targeted interventions and display unique local patterns that should be accounted for in prevention strategies. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

TU-F-CAMPUS-T-04: Variations in Nominally Identical Small Fields From Photon Jaw Reproducibility and Associated Effects On Small Field Dosimetric Parameters

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

Muir, B R; McEwen, M R

2015-06-15

Purpose: To investigate uncertainties in small field output factors and detector specific correction factors from variations in field size for nominally identical fields using measurements and Monte Carlo simulations. Methods: Repeated measurements of small field output factors are made with the Exradin W1 (plastic scintillation detector) and the PTW microDiamond (synthetic diamond detector) in beams from the Elekta Precise linear accelerator. We investigate corrections for a 0.6x0.6 cm{sup 2} nominal field size shaped with secondary photon jaws at 100 cm source to surface distance (SSD). Measurements of small field profiles are made in a water phantom at 10 cm depthmore » using both detectors and are subsequently used for accurate detector positioning. Supplementary Monte Carlo simulations with EGSnrc are used to calculate the absorbed dose to the detector and absorbed dose to water under the same conditions when varying field size. The jaws in the BEAMnrc model of the accelerator are varied by a reasonable amount to investigate the same situation without the influence of measurements uncertainties (such as detector positioning or variation in beam output). Results: For both detectors, small field output factor measurements differ by up to 11 % when repeated measurements are made in nominally identical 0.6x0.6 cm{sup 2} fields. Variations in the FWHM of measured profiles are consistent with field size variations reported by the accelerator. Monte Carlo simulations of the dose to detector vary by up to 16 % under worst case variations in field size. These variations are also present in calculations of absorbed dose to water. However, calculated detector specific correction factors are within 1 % when varying field size because of cancellation of effects. Conclusion: Clinical physicists should be aware of potentially significant uncertainties in measured output factors required for dosimetry of small fields due to field size variations for nominally identical fields.« less

Rolling epidemic of Legionnaires' disease outbreaks in small geographic areas.

PubMed

MacIntyre, C Raina; Dyda, Amalie; Bui, Chau Minh; Chughtai, Abrar Ahmad

2018-03-21

Legionnaires' disease (LD) is reported from many parts of the world, mostly linked to drinking water sources or cooling towers. We reviewed two unusual rolling outbreaks in Sydney and New York, each clustered in time and space. Data on these outbreaks were collected from public sources and compared to previous outbreaks in Australia and the US. While recurrent outbreaks of LD over time linked to an identified single source have been described, multiple unrelated outbreaks clustered in time and geography have not been previously described. We describe unusual geographic and temporal clustering of Legionella outbreaks in two cities, each of which experienced multiple different outbreaks within a small geographic area and within a short timeframe. The explanation for this temporal and spatial clustering of LD outbreaks in two cities is not clear, but climate variation and deteriorating water sanitation are two possible explanations. There is a need to critically analyse LD outbreaks and better understand changing trends to effectively prevent disease.

The spatial extent of the effect of foreclosures on crime.

PubMed

Payton, Seth B; Stucky, Thomas D; Ottensmann, John R

2015-01-01

Although neighborhood stability has long been considered a substantial determinant of crime, foreclosures have not been the subject of concerted research among criminologists until recently. A number of recent studies have examined the linkage between home foreclosures and crime. Though generally finding a significant relationship, studies have used different approaches and units of analysis. This variation led us to examine the spatial extent to which foreclosures affect a relatively small surrounding area. In this paper, we consider the spatial extent of the foreclosure effect on crime by estimating fixed effect negative binomial models using geocoded UCR data for 2003-2008 and foreclosure data to predict crime counts using the number of foreclosures within various small area radii. Results show that, independently and jointly, foreclosures are a predictor of crime up to at least a distance of 2250 feet. Importantly, that effect declines with distance. We conclude with a discussion of the implications of those findings. Copyright © 2014 Elsevier Inc. All rights reserved.

CMOS time-to-digital converter based on a pulse-mixing scheme

NASA Astrophysics Data System (ADS)

Chen, Chun-Chi; Hwang, Chorng-Sii; Liu, Keng-Chih; Chen, Guan-Hong

2014-11-01

This paper proposes a new pulse-mixing scheme utilizing both pulse-shrinking and pulse-stretching mechanisms to improve the performance of time-to-digital converters (TDCs). The temporal resolution of the conventional pulse-shrinking mechanism is determined by the size ratio between homogeneous and inhomogeneous elements. The proposed scheme which features double-stage operation derives its resolution according to the time difference between pulse-shrinking and pulse-stretching amounts. Thus, it can achieve greater immunity against temperature and ambient variations than that of the single-stage scheme. The circuit area also can be reduced by the proposed pulse-mixing scheme. In addition, this study proposes an improved cyclic delay line to eliminate the undesirable shift in the temporal resolution successfully. Therefore, the effective resolution can be controlled completely by the pulse-mixing unit to improve accuracy. The proposed TDC composed of only one cyclic delay line and one counter is fabricated in a TSMC CMOS 0.35-μm DPQM process. The chip core occupies an extremely small area of 0.02 mm2, which is the best among the related works. The experimental result shows that an effective resolution of around 53 ps within ±13% variation over a 0-100 °C temperature range is achieved. The power consumption is 90 μW at a sample rate of 1000 samples/s. In addition to the reduced area, the proposed TDC circuit achieves its resolution with less thermal-sensitivity and better fluctuations caused by process variations.

Stress Drop and Directivity Patterns Observed in Small-Magnitude (

NASA Astrophysics Data System (ADS)

Ruhl, C. J.; Hatch, R. L.; Abercrombie, R. E.; Smith, K.

2017-12-01

Recent improvements in seismic instrumentation and network coverage in the Reno, NV area have provided high-quality records of abundant microseismicity, including several swarms and clusters. Here, we discuss stress drop and directivity patterns of small-magnitude seismicity in the 2008 Mw4.9 Mogul earthquake swarm in Reno, NV and in the nearby region of an ML3.2 sequence near Virginia City, NV. In both sequences, double-difference relocated earthquakes cluster on multiple distinct structures consistent with focal mechanism and moment tensor fault plane solutions. Both sequences also show migration potentially related to fluid flow. We estimate corner frequency and stress drop using EGF-derived spectral ratios, convolving earthquake pairs (target*EGF) such that we preserve phase and recover source-time functions (STF) on a station-by-station basis. We then stack individual STFs per station for all EGF-target pairs per target earthquake, increasing the signal-to-noise of our results. By applying an azimuthal- and incidence-angle-dependent stretching factor to STFs in the time domain, we are able to invert for rupture directivity and velocity assuming both unilateral and bilateral rupture. Earthquakes in both sequences, some as low as ML2.1, show strong unilateral directivity consistent with independent fault plane solutions. We investigate and compare the relationship between rupture and migration directions on subfaults within each sequence. Average stress drops for both sequences are 4 MPa, but there is large variation in individual estimates for both sequences. Although this variation is not explained simply by any one parameter (e.g., depth), spatiotemporal variation in the Mogul swarm is distinct: coherent clusters of high and low stress drop earthquakes along the mainshock fault plane are seen, and high-stress-drop foreshocks correlate with an area of reduced aftershock productivity. These observations are best explained by a difference in rheology along the fault plane. The unprecedented detail achieved for these small magnitude earthquakes confirms that stress drop, when measured precisely, is a valuable observation of physically-meaningful fault zone properties and earthquake behavior.

Temporal variability of bacterial communities in cryoconite on an alpine glacier.

PubMed

Franzetti, Andrea; Navarra, Federico; Tagliaferri, Ilario; Gandolfi, Isabella; Bestetti, Giuseppina; Minora, Umberto; Azzoni, Roberto Sergio; Diolaiuti, Guglielmina; Smiraglia, Claudio; Ambrosini, Roberto

2017-04-01

Cryoconite holes, that is, small ponds that form on glacier surface, are considered the most biologically active environments on glaciers. Bacterial communities in these environments have been extensively studied, but often through snapshot studies based on the assumption of a general stability of community structure. In this study, the temporal variation of bacterial communities in cryoconite holes on the Forni Glacier (Italian Alps) was investigated by high throughput DNA sequencing. A temporal change of bacterial communities was observed with autotrophic Cyanobacteria populations dominating communities after snowmelt, and heterotrophic Sphingobacteriales populations increasing in abundance later in the season. Bacterial communities also varied according to hole depth and area, amount of organic matter in the cryoconite and oxygen concentration. However, variation in environmental features explained a lower fraction of the variation in bacterial communities than temporal variation. Temporal change along ablation season seems therefore more important than local environmental conditions in shaping bacterial communities of cryoconite of the Forni Glacier. These findings challenge the assumption that bacterial communities of cryoconite holes are stable. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

High within-host genetic variation of the nematode Spirocerca lupi in a high-density urban dog population.

PubMed

de Waal, Pamela J; Gous, Annemarie; Clift, Sarah J; Greeff, Jaco M

2012-06-08

The nematode worm Spirocerca lupi has a cosmopolitan distribution and can cause the death of its final canid host, typically dogs. While its life cycle, which involves a coprophagous beetle intermediate host, a number of non-obligatory vertebrate paratenic hosts and a canid final host, is well understood, surprisingly little is known about its transmission dynamics and population genetic structure. Here we sequenced cox1 to quantify genetic variation and the factors that limit gene flow in a 300 km(2) area in South Africa. Three quarters of the genetic variation, was explained by differences between worms from the same host, whereas a quarter of the variation was explained by differences between worms from different hosts. With the help of a newly derived model we conclude that while the offspring from different infrapopulations mixes fairly frequently in new hosts, the level of admixture is not enough to homogenize the parasite populations among dogs. Small infrapopulation sizes along with clumped transmission may also result in members of infrapopulations being closely related. Copyright © 2011 Elsevier B.V. All rights reserved.

Genetic variation of apolipoproteins, diet and other environmental interactions; an updated review.

PubMed

Sotos-Prieto, Mercedes; Peñalvo, José Luis

2013-01-01

This paper summarizes the recent findings from studies investigating the potential environmental modulation of the genetic variation of apolipoprotein genes on metabolic traits. We reviewed nutrigenetic studies evaluating variations on apolipoproteins-related genes and its associated response to nutrients (mostly dietary fatty acids) or any other dietary or environmental component. Most revised research studied single nucleotide polymorphism (SNP) and specific nutrients through small intervention studies, and only few interactions have been replicated in large and independent populations (as in the case of -265T > C SNP in APOA2 gene). Although current knowledge shows that variations on apolipoprotein genes may contribute to the different response on metabolic traits due to dietary interventions, evidence is still scarce and results are inconsistent. Success in this area will require going beyond the limitations of current experimental designs and explore the hypotheses within large populations. Some of these limitations are being covered by the rapidly advance in high-throughput technologies and large scale-genome wide association studies. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

Predictive models for radial sap flux variation in coniferous, diffuse-porous and ring-porous temperate trees.

PubMed

Berdanier, Aaron B; Miniat, Chelcy F; Clark, James S

2016-08-01

Accurately scaling sap flux observations to tree or stand levels requires accounting for variation in sap flux between wood types and by depth into the tree. However, existing models for radial variation in axial sap flux are rarely used because they are difficult to implement, there is uncertainty about their predictive ability and calibration measurements are often unavailable. Here we compare different models with a diverse sap flux data set to test the hypotheses that radial profiles differ by wood type and tree size. We show that radial variation in sap flux is dependent on wood type but independent of tree size for a range of temperate trees. The best-fitting model predicted out-of-sample sap flux observations and independent estimates of sapwood area with small errors, suggesting robustness in the new settings. We develop a method for predicting whole-tree water use with this model and include computer code for simple implementation in other studies. Published by Oxford University Press 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

The Needs of Students with Intersex Variations

ERIC Educational Resources Information Center

Jones, Tiffany

2016-01-01

To date, people with intersex variations have been mainly studied via small-scale clinical research, with only a small amount of reflective commentary contributed by sociocultural scholars. This paper reports on findings from a 2015 online Australian survey of 272 people with intersex variations, which aimed to redress the gap in research on this…

Ellipsoidal geometry in asteroid thermal models - The standard radiometric model

NASA Technical Reports Server (NTRS)

Brown, R. H.

1985-01-01

The major consequences of ellipsoidal geometry in an othewise standard radiometric model for asteroids are explored. It is shown that for small deviations from spherical shape a spherical model of the same projected area gives a reasonable aproximation to the thermal flux from an ellipsoidal body. It is suggested that large departures from spherical shape require that some correction be made for geometry. Systematic differences in the radii of asteroids derived radiometrically at 10 and 20 microns may result partly from nonspherical geometry. It is also suggested that extrapolations of the rotational variation of thermal flux from a nonspherical body based solely on the change in cross-sectional area are in error.

Allogenic sedimentary components of Bear Lake, Utah and Idaho

USGS Publications Warehouse

Rosenbaum, J.G.; Dean, W.E.; Reynolds, R.L.; Reheis, M.C.

2009-01-01

Bear Lake is a long-lived lake filling a tectonic depression between the Bear River Range to the west and the Bear River Plateau to the east, and straddling the border between Utah and Idaho. Mineralogy, elemental geochemistry, and magnetic properties provide information about variations in provenance of allogenic lithic material in last-glacial-age, quartz-rich sediment in Bear Lake. Grain-size data from the siliciclastic fraction of late-glacial to Holocene carbonate-rich sediments provide information about variations in lake level. For the quartz-rich lower unit, which was deposited while the Bear River fl owed into and out of the lake, four source areas are recognized on the basis of modern fluvial samples with contrasting properties that reflect differences in bedrock geology and in magnetite content from dust. One of these areas is underlain by hematite-rich Uinta Mountain Group rocks in the headwaters of the Bear River. Although Uinta Mountain Group rocks make up a small fraction of the catchment, hematite-rich material from this area is an important component of the lower unit. This material is interpreted to be glacial fl our. Variations in the input of glacial flour are interpreted as having caused quasi-cyclical variations in mineralogical and elemental concentrations, and in magnetic properties within the lower unit. The carbonate-rich younger unit was deposited under conditions similar to those of the modern lake, with the Bear River largely bypassing the lake. For two cores taken in more than 30 m of water, median grain sizes in this unit range from ???6 ??m to more than 30 ??m, with the coarsest grain sizes associated with beach or shallow-water deposits. Similar grain-size variations are observed as a function of water depth in the modern lake and provide the basis for interpreting the core grain-size data in terms of lake level. Copyright ?? 2009 The Geological Society of America.

Data-based discharge extrapolation: estimating annual discharge for a partially gauged large river basin from its small sub-basins

NASA Astrophysics Data System (ADS)

Gong, L.

2013-12-01

Large-scale hydrological models and land surface models are by far the only tools for accessing future water resources in climate change impact studies. Those models estimate discharge with large uncertainties, due to the complex interaction between climate and hydrology, the limited quality and availability of data, as well as model uncertainties. A new purely data-based scale-extrapolation method is proposed, to estimate water resources for a large basin solely from selected small sub-basins, which are typically two-orders-of-magnitude smaller than the large basin. Those small sub-basins contain sufficient information, not only on climate and land surface, but also on hydrological characteristics for the large basin In the Baltic Sea drainage basin, best discharge estimation for the gauged area was achieved with sub-basins that cover 2-4% of the gauged area. There exist multiple sets of sub-basins that resemble the climate and hydrology of the basin equally well. Those multiple sets estimate annual discharge for gauged area consistently well with 5% average error. The scale-extrapolation method is completely data-based; therefore it does not force any modelling error into the prediction. The multiple predictions are expected to bracket the inherent variations and uncertainties of the climate and hydrology of the basin. The method can be applied in both un-gauged basins and un-gauged periods with uncertainty estimation.

A Place-Oriented, Mixed-Level Regionalization Method for Constructing Geographic Areas in Health Data Dissemination and Analysis

PubMed Central

Mu, Lan; Wang, Fahui; Chen, Vivien W.; Wu, Xiao-Cheng

2015-01-01

Similar geographic areas often have great variations in population size. In health data management and analysis, it is desirable to obtain regions of comparable population by decomposing areas of large population (to gain more spatial variability) and merging areas of small population (to mask privacy of data). Based on the Peano curve algorithm and modified scale-space clustering, this research proposes a mixed-level regionalization (MLR) method to construct geographic areas with comparable population. The method accounts for spatial connectivity and compactness, attributive homogeneity, and exogenous criteria such as minimum (and approximately equal) population or disease counts. A case study using Louisiana cancer data illustrates the MLR method and its strengths and limitations. A major benefit of the method is that most upper level geographic boundaries can be preserved to increase familiarity of constructed areas. Therefore, the MLR method is more human-oriented and place-based than computer-oriented and space-based. PMID:26251551

Regional price differences and food consumption frequency among elementary school children.

PubMed

Sturm, R; Datar, A

2011-03-01

Food prices may affect diet and weight gain among youth and lead to geographic disparities in obesity. This paper examines the association between regional prices and consumption frequency of fruit/vegetables and snack items among elementary school children in the USA. Observational study using individual-level survey data of fifth-grade children (average age 11 years) and regional food prices based on store visits in 2004. Dependent variables are self-reported consumption frequency in fifth grade; primary explanatory variables are metropolitan area food prices relative to cost of living. Multivariate regression analysis. Price variation across metropolitan areas exists, and lower real prices for vegetables and fruits predict significantly higher intake frequency. Higher dairy prices predict lower frequency of milk consumption, while higher meat prices predict increased milk consumption. Similar price effects were not found for fast food or soft drink consumption. The geographic variation in food prices across the USA is sufficiently large to affect dietary patterns among youth for fruit, vegetables and milk. The price variation is either too small to affect children's consumption frequency of fast food or soft drinks, or the consumption of these foods is less price sensitive. Copyright © 2010 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Regional price differences and food consumption frequency among elementary school children

PubMed Central

Sturm, R.; Datar, A.

2010-01-01

SUMMARY Objective Food prices may affect diet and weight gain among youth and lead to geographic disparities in obesity. This paper examines the association between regional prices and consumption frequency of fruit/vegetables and snack items among elementary school children in the USA. Study design Observational study using individual-level survey data of fifth-grade children (average age 11 years) and regional food prices based on store visits in 2004. Methods Dependent variables are self-reported consumption frequency in fifth grade; primary explanatory variables are metropolitan area food prices relative to cost of living. Multivariate regression analysis. Results Price variation across metropolitan areas exists, and lower real prices for vegetables and fruits predict significantly higher intake frequency. Higher dairy prices predict lower frequency of milk consumption, while higher meat prices predict increased milk consumption. Similar price effects were not found for fast food or soft drink consumption. Discussion The geographic variation in food prices across the USA is sufficiently large to affect dietary patterns among youth for fruit, vegetables and milk. This suggests that either the price variation is too small to affect children’s consumption frequency of fast food or soft drinks, or that the consumption of these foods is less price sensitive. PMID:21315395

Oils and hydrocarbon source rocks of the Baltic syneclise

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

Kanev, S.; Margulis, L.; Bojesen-Koefoed, J.A.

Prolific source rock horizons of varying thickness, having considerable areal extent, occur over the Baltic syneclise. These source sediments are rich and have excellent petroleum generation potential. Their state of thermal maturity varies form immature in the northeastern part of the syneclise to peak generation maturity in the southwestern part of the region-the main kitchen area. These maturity variations are manifest in petroleum composition in the region. Hence, mature oils occur in the Polish and Kaliningrad areas, immature oils in small accumulations in Latvian and central Lithuanian onshore areas, and intermediate oils in areas between these extremes. The oil accumulationsmore » probably result from pooling of petroleum generated from a number of different source rocks at varying levels of thermal maturity. Hence, no single source for petroleum occurrences in the Baltic syneclise may be identified. The paper describes the baltic syneclise, source rocks, thermal maturity and oils and extracts.« less

Characterization of LANDSAT-4 TM and MSS Image Quality for Interpretation of Agricultural and Forest Resources

NASA Technical Reports Server (NTRS)

Degloria, S. D.; Colwell, R. N.

1984-01-01

Systematic analysis of both image and numeric data shows that the overall spectral, spatial, and radiometric quality of the TM data are excellent. Spectral variations in fallow fields are due to the vaiability in soil moisture and surface roughness resulting from the various stages of field preparation for small grains production. Spectrally, the addition of the first TM short wave infrared band (Band 5) significantly enhanced ability to discriminate different crop types. Bands 1, 5, and 6 contain saturated pixels due to high albedo effects, low moisture conditions, and high radiant temperatures of granite and dry, bare soil on south facing slopes, respectively. Spatially, the two fold decrease in interpixel distance and four fold decrease in area per pixel between the TM and MSS allow for improved discrimination of small fields, boundary conditions, road and stream networks in rough terrain, and small forest clearings resulting from various forest management practices.

Variation in Antiosteoporotic Drug Prescribing and Spending Across Spain. A Population-Based Ecological Cross-Sectional Study.

PubMed

Sanfélix-Gimeno, Gabriel; Librero-López, Julián; Modroño-Riaño, Gracia; Peiró, Salvador; Rodríguez-Bernal, Clara L

2018-01-01

Introduction: Evidence has shown that utilization of antiosteoporotic medications does not correspond with risk, and studies on other therapies have shown that adequacy of pharmaceutical prescribing might vary between regions. Nevertheless, very few studies have addressed the variability in osteoporotic drug consumption. We aimed to describe variations in pharmaceutical utilization and spending on osteoporotic drugs between Health Areas (HA) in Spain. Methods: Population-based cross-sectional ecological study of expenditure and utilization of the five therapeutic groups marketed for osteoporosis treatment in Spain in 2009. Small area variation analysis (SAVA) methods were used. The units of analysis were the 168 HA of 13 Spanish regions, including 7.2 million women aged 50 years and older. The main outcomes were the defined daily dose (DDD) per 1000 inhabitants and day (DDD/1000/Day) dispensed according to the pharmaceutical claims reimbursed, and the expenditure on antiosteoporotics at retail price per woman ≥50 years old and per year. Results: The average osteoporosis drug consumption was 116.8 DDD/1000W/Day, ranging from 78.5 to 158.7 DDD/1000W/Day between the HAs in the 5th and 95th percentiles. Seventy-five percent of the antiosteoporotics consumed was bisphosphonates, followed by raloxifene, strontium ranelate, calcitonins, and parathyroid hormones including teriparatide. Regarding variability by therapeutic groups, biphosphonates showed the lowest variation, while calcitonins and parathyroid hormones showed the highest variation. The annual expenditure on antiosteoporotics was €426.5 million, translating into an expenditure of €59.2 for each woman ≥50 years old and varying between €38.1 and €83.3 between HAs in the 5th and 95th percentiles. Biphosphonates, despite accounting for 79% of utilization, only represented 63% of total expenditure, while parathyroid hormones with only 1.6% of utilization accounted for 15% of the pharmaceutical spending. Conclusion: This study highlights a marked geographical variation in the prescription of antiosteoporotics, being more pronounced in the case of costly drugs such as parathyroid hormones. The differences in rates of prescribing explained almost all of the variance in drug spending, suggesting that the difference in prescription volume between territories, and not the price of the drugs, is the main source of variation in this setting. Data on geographical variation of prescription can help guide policy proposals for targeting areas with inadequate antiosteoporotic drug use.

Small- and Large-Effect Quantitative Trait Locus Interactions Underlie Variation in Yeast Sporulation Efficiency

PubMed Central

Lorenz, Kim; Cohen, Barak A.

2012-01-01

Quantitative trait loci (QTL) with small effects on phenotypic variation can be difficult to detect and analyze. Because of this a large fraction of the genetic architecture of many complex traits is not well understood. Here we use sporulation efficiency in Saccharomyces cerevisiae as a model complex trait to identify and study small-effect QTL. In crosses where the large-effect quantitative trait nucleotides (QTN) have been genetically fixed we identify small-effect QTL that explain approximately half of the remaining variation not explained by the major effects. We find that small-effect QTL are often physically linked to large-effect QTL and that there are extensive genetic interactions between small- and large-effect QTL. A more complete understanding of quantitative traits will require a better understanding of the numbers, effect sizes, and genetic interactions of small-effect QTL. PMID:22942125

Wet nitrogen deposition across the urban-intensive agricultural-rural transect of a small urban area in southwest China.

PubMed

Deng, Ouping; Zhang, Shirong; Deng, Liangji; Zhang, Chunlong; Fei, Jianbo

2018-03-01

Understanding of the spatial and temporal variation of the flux of atmospheric nitrogen (N) deposition is essential for assessment of its impact on ecosystems. However, little attention has been paid to the variability of N deposition across urban-intensive agricultural-rural transects. A continuous 2-year observational study (from January 2015 to December 2016) was conducted to determine wet N deposition across the urban-intensive agricultural-rural transect of a small urban area in southwest China. Significantly spatial and temporal variations were found in the research area. Along the urban-intensive agricultural-rural transect, the TN and NH 4 + -N deposition first increased and then decreased, and the NO 3 - -N and dissolved organic N (DON) deposition decreased continuously. Wet N deposition was mainly affected by the districts of agro-facilities, roads and build up lands. Wet NH 4 + -N deposition had non-seasonal emission sources including industrial emissions and urban excretory wastes in urban districts and seasonal emission sources such as fertilizer and manure volatilization in the other districts. However, wet NO 3 - -N deposition had seasonal emission sources such as industrial emissions and fireworks in urban district and non-seasonal emission sources such as transportation in the other districts. Deposition of DON was likely to have had similar sources to NO 3 - -N deposition in rural district, and high-temperature-dependent sources in urban and intensive agricultural districts. Considering the annual wet TN deposition in the intensive agricultural district was about 11.1% of the annual N fertilizer input, N fertilizer rates of crops should be reduced in this region to avoid the excessive application, and the risk of N emissions to the environment.

Spatial Variability in Column CO2 Inferred from High Resolution GEOS-5 Global Model Simulations: Implications for Remote Sensing and Inversions

NASA Technical Reports Server (NTRS)

Ott, L.; Putman, B.; Collatz, J.; Gregg, W.

2012-01-01

Column CO2 observations from current and future remote sensing missions represent a major advancement in our understanding of the carbon cycle and are expected to help constrain source and sink distributions. However, data assimilation and inversion methods are challenged by the difference in scale of models and observations. OCO-2 footprints represent an area of several square kilometers while NASA s future ASCENDS lidar mission is likely to have an even smaller footprint. In contrast, the resolution of models used in global inversions are typically hundreds of kilometers wide and often cover areas that include combinations of land, ocean and coastal areas and areas of significant topographic, land cover, and population density variations. To improve understanding of scales of atmospheric CO2 variability and representativeness of satellite observations, we will present results from a global, 10-km simulation of meteorology and atmospheric CO2 distributions performed using NASA s GEOS-5 general circulation model. This resolution, typical of mesoscale atmospheric models, represents an order of magnitude increase in resolution over typical global simulations of atmospheric composition allowing new insight into small scale CO2 variations across a wide range of surface flux and meteorological conditions. The simulation includes high resolution flux datasets provided by NASA s Carbon Monitoring System Flux Pilot Project at half degree resolution that have been down-scaled to 10-km using remote sensing datasets. Probability distribution functions are calculated over larger areas more typical of global models (100-400 km) to characterize subgrid-scale variability in these models. Particular emphasis is placed on coastal regions and regions containing megacities and fires to evaluate the ability of coarse resolution models to represent these small scale features. Additionally, model output are sampled using averaging kernels characteristic of OCO-2 and ASCENDS measurement concepts to create realistic pseudo-datasets. Pseudo-data are averaged over coarse model grid cell areas to better understand the ability of measurements to characterize CO2 distributions and spatial gradients on both short (daily to weekly) and long (monthly to seasonal) time scales

Are vegetated areas of mangroves attractive to juvenile and small fish? The case of Dongzhaigang Bay, Hainan Island, China

NASA Astrophysics Data System (ADS)

Wang, Mao; Huang, Zhenyuan; Shi, Fushan; Wang, Wenqing

2009-11-01

Well-developed aerial roots of mangroves make it difficult to study how fish utilize the mangrove forest as a habitat. In the present study, we compared the differences in fish assemblages in three major types of habitats of mangrove estuary (vegetated area, treeless mudflat, and creek) of a mangrove bay in Hainan Island, China, at different seasons during two consecutive years. Three types of gears, centipede net, gill net and cast net, were used in the different habitats of mangrove estuary and sampling efficiencies among gears were evaluated. Centipede nets were used in all the three types of habitats and cast nets and gill nets in treeless mudflats and creeks. Fish assemblages were dependent on gears used. Centipede net could efficiently catch fish occurring both inside and outside of vegetated areas efficiently. A total of 115 fish species in 51 families were collected. In terms of numbers of species per family, Gobiidae was the most diverse (17 species), followed by Mugilidae (5 species). Almost all of the fish were juvenile or small fish and few predators were recorded, implying low predation pressure in the bay. ANOVA analysis showed that significant seasonal and spatial variation existed in species richness, abundance, and biomass, which were less in the vegetated areas than those of treeless mudflats and creeks. The attraction of vegetated areas to fish was less than that of creeks and mudflats. Many species were specific to a particular habitat type, 4 species occurring exclusively in the creeks, 45 species occurring exclusively in the treeless mudflats, and 5 species occurring exclusively in the vegetated areas. The results indicated that mangrove estuaries were potentially attractive habitats for juvenile and small fish, but this attraction was accomplished by a connection of vegetated areas, treeless mudflats and creeks, not only by vegetated areas.

Weather Condition dominates the Regional PM2.5 Pollutions in the Eastern Coastal Provinces of China during winter

NASA Astrophysics Data System (ADS)

Cai, Zhe; Jiang, Fei; Chen, Jingming; Jiang, Ziqiang

2017-04-01

China has been suffering from severe particulate matter (PM) pollution in recent years. Both pollution area and pollution levels are increasing gradually. The PM pollution episodes not only occur in the traditional developed areas like Yangtze River Delta (YRD) and Beijing-Tianjin-Hebei (BTH) region, but also frequently happen in the whole eastern coastal provinces (ECPs) of China. Based on hourly PM2.5 concentrations during December 2013 February 2014 of 55 cities located in the ECPs, we investigated the spatial and temporal variabilities of PM2.5 concentrations and the corresponding meteorological conditions during winter. The results shown that basically the seasonal mean concentrations over the whole ECPs exceeded the China's national standard of 75 μg/m3, and the most polluted area with mean concentrations greater than 150 μg/m3 were located in the southwest of Hebei and the west of Shandong provinces. From December to February, there was a decrease trend for the PM2.5 pollution in most areas, especially in the YRD region, while the PM2.5 concentrations over north of Hebei province increased. The spatial distributions and monthly variations are strongly related to the weather conditions. Overall, severe PM pollution was corresponding to a stable weather condition, i.e., small Sea Level Pressure (SLP) gradient, lower Planetary Boundary Layer (PBL) height and weaker wind fields. Statistics shown that the changes of mean PM2.5 concentrations over the ECPs region usually lagged behind the variations of PBL height and wind speeds about 12 18 hours. The variations of weather conditions could explain about 71% (R2) of the overall changes of PM2.5 concentrations in the ECPs region. This study gives a full insight into the PM2.5 pollution in the area of eastern coastal provinces of China during winter, which would be helpful to predict and control the PM2.5 pollution for this area in the future.

Gate line edge roughness amplitude and frequency variation effects on intra die MOS device characteristics

NASA Astrophysics Data System (ADS)

Hamadeh, Emad; Gunther, Norman G.; Niemann, Darrell; Rahman, Mahmud

2006-06-01

Random fluctuations in fabrication process outcomes such as gate line edge roughness (LER) give rise to corresponding fluctuations in scaled down MOS device characteristics. A thermodynamic-variational model is presented to study the effects of LER on threshold voltage and capacitance of sub-50 nm MOS devices. Conceptually, we treat the geometric definition of the MOS devices on a die as consisting of a collection of gates. In turn, each of these gates has an area, A, and a perimeter, P, defined by nominally straight lines subject to random process outcomes producing roughness. We treat roughness as being deviations from straightness consisting of both transverse amplitude and longitudinal wavelength each having lognormal distribution. We obtain closed-form expressions for variance of threshold voltage ( Vth), and device capacitance ( C) at Onset of Strong Inversion (OSI) for a small device. Using our variational model, we characterized the device electrical properties such as σ and σC in terms of the statistical parameters of the roughness amplitude and spatial frequency, i.e., inverse roughness wavelength. We then verified our model with numerical analysis of Vth roll-off for small devices and σ due to dopant fluctuation. Our model was also benchmarked against TCAD of σ as a function of LER. We then extended our analysis to predict variations in σ and σC versus average LER spatial frequency and amplitude, and oxide-thickness. Given the intuitive expectation that LER of very short wavelengths must also have small amplitude, we have investigated the case in which the amplitude mean is inversely related to the frequency mean. We compare with the situation in which amplitude and frequency mean are unrelated. Given also that the gate perimeter may consist of different LER signature for each side, we have extended our analysis to the case when the LER statistical difference between gate sides is moderate, as well as when it is significantly large.

Enhanced, targeted sampling of high-dimensional free-energy landscapes using variationally enhanced sampling, with an application to chignolin

PubMed Central

Shaffer, Patrick; Valsson, Omar; Parrinello, Michele

2016-01-01

The capabilities of molecular simulations have been greatly extended by a number of widely used enhanced sampling methods that facilitate escaping from metastable states and crossing large barriers. Despite these developments there are still many problems which remain out of reach for these methods which has led to a vigorous effort in this area. One of the most important problems that remains unsolved is sampling high-dimensional free-energy landscapes and systems that are not easily described by a small number of collective variables. In this work we demonstrate a new way to compute free-energy landscapes of high dimensionality based on the previously introduced variationally enhanced sampling, and we apply it to the miniprotein chignolin. PMID:26787868

Geographic variation in inquest rates in Australia.

PubMed

Walter, Simon J; Bugeja, Lyndal; Spittal, Matthew J; Studdert, David M

2012-11-01

This paper examines the relationship between the remoteness of locations in which deaths occur and coroners' decisions to hold inquests. We analysed 16,242 deaths investigated by coroners in three Australian states over 7.5 yrs. We used a choropleth map to show inquest rates in each remoteness locality (excluding deaths for which inquests were mandated by statute). We then used adjusted logistic regression to assess the association between the remoteness of a death's location and the odds coroners would select it for investigation by inquest. We found the remoteness of a death's location strongly and positively predicts the chance that an inquest will be held. Like analogous findings in the delivery of health services, this small-area variation in legal decision making raises questions of appropriateness. Copyright © 2012 Elsevier Ltd. All rights reserved.

Estimating cigarette tax avoidance and evasion: evidence from a national sample of littered packs

PubMed Central

Barker, Dianne C; Wang, Shu; Merriman, David; Crosby, Andrew; Resnick, Elissa A; Chaloupka, Frank J

2016-01-01

Introduction A number of recent studies document the proportion of all cigarette packs that are ‘contraband’ using discarded packs to measure tax avoidance and evasion, which we call tax non-compliance. To date, academic studies using discarded packs focused on relatively small geographical areas such as a city or a neighbourhood. Methods We visited 160 communities across 38 US states in 2012 and collected data from littered cigarette packs as part of the State and Community Tobacco Control (SCTC) Research Initiative and the Bridging the Gap Community Obesity Measures Project (BTG-COMP). Data collectors were trained in a previously tested littered pack data collection protocol. Results Field teams collected 2116 packs with cellophane across 132 communities. We estimate a national tax non-compliance rate of 18.5% with considerable variation across regions. Suburban areas had lower non-compliance than urban areas as well as areas with high and low median household income areas compared with middle income areas. Discussion We present the first academic national study of tax non-compliance using littered cigarette packs. We demonstrate the feasibility of meaningful large-scale data collection using this methodology and document considerable variation in tax non-compliance across areas, suggesting that both policy differences and geography may be important in control of illicit tobacco use. Given the geography of open borders among countries with varying tax rates, this simple methodology may be appropriate to estimate tax non-compliance in countries that use tax stamps or other pack markings, such as health warnings. PMID:27697946

Demographic response to environmental variation in breeding, stopover and non-breeding areas in a migratory passerine.

PubMed

Schaub, Michael; Jakober, Hans; Stauber, Wolfgang

2011-10-01

Demographic rates of migratory species passing through several areas during their annual cycle may be affected by environmental conditions at each of these areas. Recent studies provide evidence that their impact is not necessarily immediate, but can be delayed. We studied survival, reproductive success and arrival date at the breeding grounds of red-backed shrikes Lanius collurio, a trans-Saharan migrant, in relation to weather and vegetation on the breeding grounds, the stopover sites during migration and in the wintering areas. These environmental factors are used as proxy of the shrike's food supply. We analysed detailed demographic data of some 4,600 individuals from 25 years with multistate capture-recapture and mixed models. Survival probabilities of juveniles and breeders of both sexes varied in parallel across time, suggesting that all cohorts were sensitive to similar causes of mortality. Reproductive performance increased with temperature and decreased with rainfall on the breeding area. Moreover, it increased with vegetation cover in the Sahelian stopover area used on autumn migration suggesting a carry-over effect. Arrival date was negatively affected by spring temperatures in the breeding area. Hence, demographic rates were affected by environmental factors on the breeding grounds, but also outside and elsewhere. This suggests that the shrike's population dynamics are driven by environmental factors operating at various scales of space and time. However, only a small amount of the temporal variation in demographic rates is explained by the environmental factors considered, suggesting that additional factors, such as those operating during migration, might be important.

Time variations in the mechanical characteristics of local crustal segments according to seismic observations

NASA Astrophysics Data System (ADS)

Kocharyan, G. G.; Gamburtseva, N. G.; Sanina, I. A.; Danilova, T. V.; Nesterkina, M. A.; Gorbunova, E. M.; Ivanchenko, G. N.

2011-04-01

The results of the seismic observations made with two different experimental setups are presented. In the first case, the signals produced by underground nuclear explosions at the Semipalatinsk Test Site were measured on a linear profile, which allowed one to definitely outline the areas where the mechanical properties of rocks experienced considerable time variations. In the second case, the waves excited by the open-pit mine blasts recorded at a small-aperture seismic array at the Mikhnevo Geophysical Station (Institute of Geosphere Dynamics, Russian Academy of Sciences) on the East European Platform favored the estimation of variations in the integral characteristics of the seismic path. Measurements in aseismic regions characterized by diverse geological structure and different tectonic conditions revealed similar effects of the strong dependency of seismic parameters on the time of explosions. Here, the variations experienced by the maximum amplitudes of oscillations and irrelevant to seasonal changes or local conditions reached a factor of two. The generic periods of these variations including the distinct annual rhythm are probably the fragments of a lower-frequency process. The obtained results suggest that these variations are due to changes in the stressstrain state of active fault zones, which, in turn, can be associated with the macroscale motion of large blocks triggered by tidal strains, tectonic forces and, possibly, variations in the rate of the Earth's rotation.

Regional variation in acute care length of stay after orthopaedic surgery total joint replacement surgery and hip fracture surgery.

PubMed

Fitzgerald, John D; Weng, Haoling H; Soohoo, Nelson F; Ettner, Susan L

2013-01-01

To examine change in regional variations in acute care length of stay (LOS) after orthopedic surgery following expiration of the New York (NY) State exemption to the Prospective Payment System and implementation of the Medicare Short Stay Transfer Policy. Time series analyses were conducted to evaluate change in LOS across regions after policy implementations. Small area analyses were conducted to examine residual variation in LOS. The dataset included A 100% sample of fee-for-service Medicare patients undergoing surgical repair for hip fracture or elective joint replacement surgery between 1996 and 2001. Data files from Centers for Medicare and Medicaid Services 1996-2001 Medicare Provider Analysis and Review file, 1999 Provider of Service file, and data from the 2000 United States Census were used for analysis. In 1996, LOS in NY after orthopedic procedures was much longer than the remainder of the country. After policy changes, LOS fell. However, significant residual variation in LOS persisted. This residual variation was likely partly explained by differences variation in regional managed care market penetration, patient management practices and unmeasured characteristics associated with the hospital location. NY hospitals responded to changes in reimbursement policy, reducing variation in LOS. However, even after 5 years of financial pressure to constrain costs, other factors still have a strong impact on delivery of patient care.

Forage digestibility and intake by lesser snow geese: effects of dominance and resource heterogeneity

USGS Publications Warehouse

Hupp, Jerry W.; White, Robert G.; Sedinger, James S.; Robertson, Donna G.

1996-01-01

We measured forage intake, digestibility, and retention time for 11 free-ranging, human-imprinted lesser snow geese (Chen caerulescens caerulescens) as they consumed underground stembases of tall cotton-grass (Eriophorum angustifolium) on an arctic staging area in northeastern Alaska. Geese fed in small patches (x̄=21.5 m2) of forage that made up ≤3% of the study area and consisted of high-quality “aquatic graminoid” and intermediate-quality “wet sedge” vegetation types. Dominant geese spent more time feeding in aquatic graminoid areas (r=0.61), but less total time feeding and more time resting than subdominant geese. Subdominant geese were displaced to areas of wet sedge where cotton-grass was a smaller proportion of underground biomass. Geese metabolized an average of 48% of the organic matter in stembases and there was a positive correlation between dominance and organic matter metabolizability (r=0.61). Total mean retention time of forage was 1.37 h and dry matter intake was 14.3 g/h. Snow geese that stage on the coastal plain of the Beaufort Sea likely use an extensive area because they consume a large mass of forage and exploit habitats that are patchily distributed and make up a small percentage of the landscape. Individual variation in nutrient absorption may result from agonistic interactions in an environment where resources are heterogeneously distributed.

Municipal health expectancy in Japan: decreased healthy longevity of older people in socioeconomically disadvantaged areas.

PubMed

Fukuda, Yoshiharu; Nakamura, Keiko; Takano, Takehito

2005-06-14

Little is known about small-area variation in healthy longevity of older people and its socioeconomic correlates. This study aimed to estimate health expectancy at 65 years (HE65) at the municipal level in Japan, and to examine its relation to area socio-demographic conditions. HE65 of municipalities (N = 3361) across Japan was estimated by a linear regression formula with life expectancy at 65 years and the prevalence of those certificated as needing nursing care. The relation between HE65 and area socio-demographic indicators was examined using correlation coefficients. The estimated HE65 (years) ranged from 13.13 to 17.39 for men and from 14.84 to 20.53 for women. HE65 was significantly positively correlated with the proportion of elderly and per capita income, and negatively correlated with the percentage of households of a single elderly person, divorce rate, and unemployment rate. These relations were stronger in large municipalities (with a population of more than 100,000) than in small and medium-size municipalities. A decrease in healthy longevity of older people was associated with a higher percentage of households of a single elderly person and divorce rate, and lower socioeconomic conditions. This study suggests that older people in urban areas are susceptible to socio-demographic factors, and a social support network for older people living in socioeconomically disadvantaged conditions should be encouraged.

Morphometric variations of laelapine mite (Acari: Mesostigmata) populations infesting small mammals (Mammalia) in Brazil.

PubMed

Martins-Hatano, F; Gettinger, D; Manhães, M L; Bergallo, H G

2012-08-01

The goal of this study was to evaluate the morphometric variation of laelapine populations (Acari, Mesostigmata) associated with neotropical oryzomyine rodents at different geographic localities in Brazil. Three nominal mite species were selected for study, all infesting the pelage of small mammals at different localities in Rio de Janeiro, Espírito Santo, Bahia, and the Federal District, Brazil. To analyse morphometric characteristics, thirty-seven morphological characters distributed across the whole body of each specimen were measured. We use the Analysis of Principal Components, extracting the three first axes and projecting each mite in these axes. Major species level changes in the taxonomy of the host mammals allows an independent examination of morphometric variation of mites infesting a set of distinctly different host species at different geographic localities. Gigantolaelaps vitzthumi and Laelaps differens are associated with oryzomyine rodents of the genus Cerradomys, and consistently showed a tendency to cluster by host phylogeny. Laelaps manguinhosi associated with Nectomys rattus in central Brazil is morphometrically distinct from mites infesting N. squamipes in the coastal restingas of Rio de Janeiro and Espírito Santo. The results obtained here indicate that laelapine mite populations can vary among geographic areas and among phylogenetically related host species. Clearly, the study of these mites at the population level can be an important tool for clarifying the taxonomy of both mites and hosts.

Quantifying the performance of in vivo portal dosimetry in detecting four types of treatment parameter variations

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

Bojechko, C.; Ford, E. C., E-mail: eford@uw.edu

Purpose: To quantify the ability of electronic portal imaging device (EPID) dosimetry used during treatment (in vivo) in detecting variations that can occur in the course of patient treatment. Methods: Images of transmitted radiation from in vivo EPID measurements were converted to a 2D planar dose at isocenter and compared to the treatment planning dose using a prototype software system. Using the treatment planning system (TPS), four different types of variability were modeled: overall dose scaling, shifting the positions of the multileaf collimator (MLC) leaves, shifting of the patient position, and changes in the patient body contour. The gamma passmore » rate was calculated for the modified and unmodified plans and used to construct a receiver operator characteristic (ROC) curve to assess the detectability of the different parameter variations. The detectability is given by the area under the ROC curve (AUC). The TPS was also used to calculate the impact of the variations on the target dose–volume histogram. Results: Nine intensity modulation radiation therapy plans were measured for four different anatomical sites consisting of 70 separate fields. Results show that in vivo EPID dosimetry was most sensitive to variations in the machine output, AUC = 0.70 − 0.94, changes in patient body habitus, AUC = 0.67 − 0.88, and systematic shifts in the MLC bank positions, AUC = 0.59 − 0.82. These deviations are expected to have a relatively small clinical impact [planning target volume (PTV) D{sub 99} change <7%]. Larger variations have even higher detectability. Displacements in the patient’s position and random variations in MLC leaf positions were not readily detectable, AUC < 0.64. The D{sub 99} of the PTV changed by up to 57% for the patient position shifts considered here. Conclusions: In vivo EPID dosimetry is able to detect relatively small variations in overall dose, systematic shifts of the MLC’s, and changes in the patient habitus. Shifts in the patient’s position which can introduce large changes in the target dose coverage were not readily detected.« less

Trends in abundance of collared lemmings near Cape Churchill, Manitoba, Canada

USGS Publications Warehouse

Reiter, M.E.; Andersen, D.E.

2008-01-01

Regular, multiannual cycles observed in the population abundance of small mammals in many arctic and subarctic ecosystems have stimulated substantial research, particularly among population ecologists. Hypotheses of mechanisms generating regular cycles include predator-prey interactions, limitation of food resources, and migration or dispersal, as well as abiotic factors such as cyclic climatic variation and environmental stochasticity. In 2004 and 2005, we used indirect methods to estimate trends in population size of Richardson's collared lemmings (Dicrostonyx richardsoni) retrospectively, and evaluated the extent of synchrony between lemming populations at 2 coastal tundra study areas separated by approximately 60 km near Cape Churchill, Manitoba, Canada. We collected scars on willow plants (Salix) resulting from lemming feeding. Ages of scars ranged from 0 to 13 years at both study areas. Scar-age frequency appeared cyclic and we used nonlinear Poisson regression to model the observed scar-age frequency. Lemming populations cycled with 2.8-year periodicity and the phase of the cycle was synchronous between the 2 study areas. We suggest that our approach could be applied in multiple settings and may provide the most efficient way to gather data on small mammals across both space and time in a diversity of landscapes. ?? 2008 American Society of Mammalogists.

WIC program participation--a marketing approach.

PubMed Central

Buechner, J S; Scott, H D; Smith, J L; Humphrey, A B

1991-01-01

Recent evaluation studies have described the benefits accruing to low-income women and children who participate in the Special Supplemental Food Program for Women, Infants, and Children (WIC). However, participation is not uniform among all groups of eligible persons. This study examines the geographic variation in WIC participation rates of eligible pregnant women in Rhode Island to determine whether the program is effective in reaching the neediest segments of the population. Eight groups of small geographic areas in Rhode Island (census tracts) were formed on the basis of need for maternal and child health services, as determined from a statistical method employing factor and cluster analysis of existing health and sociodemographic data. Among these eight groups, participation rates in WIC during 1983-84 ranged from 46 percent to more than 100 percent of estimated eligible pregnant women. The rates were positively correlated with measures of need, strongly (r = 0.92) with an index of maternal risk, and less strongly (r = 0.79) with an index of birth outcomes. The results of this study have enabled the Rhode Island WIC Program to direct its outreach efforts more specifically to geographic areas where the need for the program's assistance is greatest. The procedures described in this report comprise a technique that can be generally applied to measure program effectiveness in marketing and outreach where relevant data are available by small geographic areas. The data requirements are (a) population-based estimates of program need and (b) program utilization measures. If these data can be aggregated to a common set of small geographic areas, the use of marketing analysis techniques becomes possible, and program benefits in the area of outreach and recruitment can be realized. PMID:1910189

Research on Multi Hydrological Models Applicability and Modelling Data Uncertainty Analysis for Flash Flood Simulation in Hilly Area

NASA Astrophysics Data System (ADS)

Ye, L.; Wu, J.; Wang, L.; Song, T.; Ji, R.

2017-12-01

Flooding in small-scale watershed in hilly area is characterized by short time periods and rapid rise and recession due to the complex underlying surfaces, various climate type and strong effect of human activities. It is almost impossible for a single hydrological model to describe the variation of flooding in both time and space accurately for all the catchments in hilly area because the hydrological characteristics can vary significantly among different catchments. In this study, we compare the performance of 5 hydrological models with varying degrees of complexity for simulation of flash flood for 14 small-scale watershed in China in order to find the relationship between the applicability of the hydrological models and the catchments characteristics. Meanwhile, given the fact that the hydrological data is sparse in hilly area, the effect of precipitation data, DEM resolution and their interference on the uncertainty of flood simulation is also illustrated. In general, the results showed that the distributed hydrological model (HEC-HMS in this study) performed better than the lumped hydrological models. Xinajiang and API models had good simulation for the humid catchments when long-term and continuous rainfall data is provided. Dahuofang model can simulate the flood peak well while the runoff generation module is relatively poor. In addition, the effect of diverse modelling data on the simulations is not simply superposed, and there is a complex interaction effect among different modelling data. Overall, both the catchment hydrological characteristics and modelling data situation should be taken into consideration in order to choose the suitable hydrological model for flood simulation for small-scale catchment in hilly area.

Environmental effects of hydrothermal alteration and historical mining on water and sediment quality in Central Colorado

USGS Publications Warehouse

Church, S.E.; Fey, D. L.; Klein, T.L.; Schmidt, T.S.; Wanty, R.B.; deWitt, E.H.; Rockwell, B.W.; San, Juan C.A.

2009-01-01

The U.S. Geological Survey conducted an environmental assessment of 198 catchments in a 54,000-km2 area of central Colorado, much of which is on Federal land. The Colorado Mineral Belt, a northeast-trending zone of historical base- and precious-metal mining, cuts diagonally across the study area. The investigation was intended to test the hypothesis that degraded water and sediment quality are restricted to catchments in which historical mining has occurred. Water, streambed sediment, and aquatic insects were collected from (1) catchments underlain by single lithogeochemical units, some of which were hydrothermally altered, that had not been prospected or mined; (2) catchments that contained evidence of prospecting, most of which contain hydrothermally altered rock, but no historical mining; and (3) catchments, all of which contain hydrothermally altered rock, where historical but now inactive mines occur. Geochemical data determined from catchments that did not contain hydrothermal alteration or historical mines met water quality criteria and sediment quality guidelines. Base-metal concentrations from these types of catchments showed small geochemical variations that reflect host lithology. Hydrothermal alteration and mineralization typically are associated with igneous rocks that have intruded older bedrock in a catchment. This alteration was regionally mapped and characterized primarily through the analysis of remote sensing data acquired by the ASTER satellite sensor. Base-metal concentrations among unaltered rock types showed small geochemical variations that reflect host lithology. Base-metal concentrations were elevated in sediment from catchments underlain by hydrothermally altered rock. Classification of catchments on the basis of mineral deposit types proved to be an efficient and accurate method for discriminating catchments that have degraded water and sediment quality. Only about 4.5 percent of the study area has been affected by historical mining, whereas a larger part of the study area is underlain by hydrothermally altered rock that has weathered to produce water and sediment with naturally elevated geochemical baselines. 

The Geography of Diabetes among the General Adults Aged 35 Years and Older in Bangladesh: Recent Evidence from a Cross-Sectional Survey

PubMed Central

Khan, Md. Mobarak Hossain; Gruebner, Oliver; Kraemer, Alexander

2014-01-01

Objective To report geographical variations of sex-specific diabetes by place of residence (large cities/city corporations, small towns/other urban areas, rural areas) and region of residence (divided into seven divisions) among general adults (35+ years of age) in Bangladesh. Methods The recent cross-sectional data, extracted from the nationally representative Bangladesh Demographic and Health Survey 2011, was used. A total of 3,720 men and 3,823 women aged 35+ years, who participated in the fasting blood sugar testing, were analysed. Any person with either fasting plasma glucose level (mmol/L) ≥7.0 or taking medication for diabetes was considered as a person with diabetes. Results The prevalence of diabetes was 10.6% in men and 11.3% in women. Bivariable analyses indicated significant variations of diabetes by both geographical variables. The prevalence was highest in city corporations (men 18.0%, women 22.3%), followed by small towns (men 13.6%, women 15.2%) and rural areas (men 9.3%, women 9.5%). Regional disparities in diabetes prevalence were also remarkable, with the highest prevalence in Chittagong division and lowest prevalence in Khulna division. Multivariable logistic regression analyses provided mixed patterns of geographical disparities (depending on the adjusted variables). Some other independent risk factors for diabetes were advancing age, higher level of education and wealth, having TV (a proxy indicator of physical activity), overweight/obesity and hypertension. Conclusions Over 10% of the general adults aged 35 years and older were having diabetes. Most of the persons with diabetes were unaware of this before testing fasting plasma glucose level. Although significant disparities in diabetes prevalence by geographical variables were observed, such disparities are very much influenced by the adjusted variables. Finally, we underscore the necessities of area-specific strategies including early diagnosis and health education programmes for changing lifestyles to reduce the risk of diabetes in Bangladesh. PMID:25356781

The geography of diabetes among the general adults aged 35 years and older in Bangladesh: recent evidence from a cross-sectional survey.

PubMed

Khan, Md Mobarak Hossain; Gruebner, Oliver; Kraemer, Alexander

2014-01-01

To report geographical variations of sex-specific diabetes by place of residence (large cities/city corporations, small towns/other urban areas, rural areas) and region of residence (divided into seven divisions) among general adults (35+ years of age) in Bangladesh. The recent cross-sectional data, extracted from the nationally representative Bangladesh Demographic and Health Survey 2011, was used. A total of 3,720 men and 3,823 women aged 35+ years, who participated in the fasting blood sugar testing, were analysed. Any person with either fasting plasma glucose level (mmol/L) ≥7.0 or taking medication for diabetes was considered as a person with diabetes. The prevalence of diabetes was 10.6% in men and 11.3% in women. Bivariable analyses indicated significant variations of diabetes by both geographical variables. The prevalence was highest in city corporations (men 18.0%, women 22.3%), followed by small towns (men 13.6%, women 15.2%) and rural areas (men 9.3%, women 9.5%). Regional disparities in diabetes prevalence were also remarkable, with the highest prevalence in Chittagong division and lowest prevalence in Khulna division. Multivariable logistic regression analyses provided mixed patterns of geographical disparities (depending on the adjusted variables). Some other independent risk factors for diabetes were advancing age, higher level of education and wealth, having TV (a proxy indicator of physical activity), overweight/obesity and hypertension. Over 10% of the general adults aged 35 years and older were having diabetes. Most of the persons with diabetes were unaware of this before testing fasting plasma glucose level. Although significant disparities in diabetes prevalence by geographical variables were observed, such disparities are very much influenced by the adjusted variables. Finally, we underscore the necessities of area-specific strategies including early diagnosis and health education programmes for changing lifestyles to reduce the risk of diabetes in Bangladesh.

Quantification of regional nonuniformity and paradoxical intramural mechanics in hypertrophic cardiomyopathy by high frame rate ultrasound myocardial strain mapping.

PubMed

Sengupta, Partho P; Mehta, Vimal; Arora, Ramesh; Mohan, Jagdish C; Khandheria, Bijoy K

2005-07-01

This study tested the hypothesis that linear mapping of regional myocardial strain comprehensively assesses variations in regional myocardial function in hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy is characterized by disorganized myocardial architecture that results in spatial and temporal nonuniformity of regional function. Left ventricular deformation was quantified in 20 patients with hypertrophic cardiomyopathy and compared with 25 age- and sex-matched control subjects. Abnormalities in subendocardial strain ranged from reduced longitudinal shortening to paradoxical systolic lengthening and delayed regional longitudinal contractions that were often located in small subsegmental areas. These variations were underestimated significantly by arbitrary measurements compared with linear mapping, in which a region of interest was moved across the longitudinal length of left ventricle (difference of peak and least strain, 10.7% +/- 5.1% vs 17% +/- 5.5%; P < .001). Echocardiographic assessment of variations in regional strain requires careful mapping and may be inappropriately assessed if left ventricular segments are sampled at arbitrary focal locations.

Entropy, extremality, euclidean variations, and the equations of motion

NASA Astrophysics Data System (ADS)

Dong, Xi; Lewkowycz, Aitor

2018-01-01

We study the Euclidean gravitational path integral computing the Rényi entropy and analyze its behavior under small variations. We argue that, in Einstein gravity, the extremality condition can be understood from the variational principle at the level of the action, without having to solve explicitly the equations of motion. This set-up is then generalized to arbitrary theories of gravity, where we show that the respective entanglement entropy functional needs to be extremized. We also extend this result to all orders in Newton's constant G N , providing a derivation of quantum extremality. Understanding quantum extremality for mixtures of states provides a generalization of the dual of the boundary modular Hamiltonian which is given by the bulk modular Hamiltonian plus the area operator, evaluated on the so-called modular extremal surface. This gives a bulk prescription for computing the relative entropies to all orders in G N . We also comment on how these ideas can be used to derive an integrated version of the equations of motion, linearized around arbitrary states.

Imaging the Variscan suture at the KTB deep drilling site, Germany

NASA Astrophysics Data System (ADS)

Bianchi, Irene; Bokelmann, Götz

2018-03-01

The upper crust of the KTB (Kontinentales Tiefbohrprogramm) area in Southeastern Germany is a focal point for the Earth Science community due to the huge amount of information collected throughout the last thirty years. In this study we explore the crustal structure of the KTB area through the application of the receiver function (RF) technique to a new data set recorded by 9 temporary seismic stations and 1 permanent station. We aim to unravel the isotropic structure and compare our results with previous information from the reflection profiles collected during the initial site investigations. Due to the large amount of information collected by previous studies, in terms of P-wave velocity, depth and location of major reflectors, depth reconstruction of major faults zones, this area represents a unique occasion to test the resolution capability of a passive seismological study performed by the application of the RF. We aim to verify which contribution could be given by the application of the receiver functions technique, for future studies, in order to get clear images of the deep structure, and up to which resolution. The RF technique has apparently not been applied in the area before, yet it may give useful additional insight in subsurface structure, particularly at depths larger than the maximum depth reached by drilling, but also on structures in the upper crust, around the area that has been studied in detail previously. In our results vS-depth profiles for stations located on the same geological units display common features and show shallow S-wave velocities typical of the outcropping geological units (i.e. sedimentary basin, granites, metamorphic rocks). At around 10 km depth we observe a strong velocity increase beneath all stations. For the stations located in the center of the area, this variation is weaker, which we assume to be the signature of the main tectonic suture in the area (i.e. the Saxothuringian-Moldanubian suture), along an West-to-East extended region, may be due to the presence of the allochthonous klippe trapped between the main crustal terrains that came in touch during the Variscan orogeny. In the lower crust we see only small variations throughout the area, at the resolution that is possible with a small temporary experiment with just 10 stations.

Imaging the Variscan suture at the KTB deep drilling site, Germany

NASA Astrophysics Data System (ADS)

Bianchi, Irene; Bokelmann, Götz

2018-06-01

The upper crust of the KTB (Kontinentales Tiefbohrprogramm) area in the Southeastern Germany is a focal point for the Earth Science community due to the huge amount of information collected throughout the last 30 yr. In this study, we explore the crustal structure of the KTB area through the application of the Receiver Function (RF) technique to a new data set recorded by nine temporary seismic stations and one permanent station. We aim to unravel the isotropic structure and compare our results with previous information from the reflection profiles collected during the initial site investigations. Due to the large amount of information collected by previous studies, in terms of P-wave velocity, depth and location of major reflectors, depth reconstruction of major faults zones, this area represents a unique occasion to test the resolution capability of a passive seismological study performed by the application of the RF. We aim to verify which contribution could be given by the application of the RF technique, for future studies, in order to get clear images of the deep structure and up to which resolution. The RF technique has apparently not been applied in the area before, yet it may give useful additional insight in subsurface structure, particularly at depths larger than the maximum depth reached by drilling, but also on structures in the upper crust, around the area that has been studied in detail previously. In our results vS-depth profiles for stations located on the same geological units display common features and show shallow S-wave velocities typical of the outcropping geological units (i.e. sedimentary basin, granites and metamorphic rocks). At around 10 km depth, we observe a strong velocity increase beneath all stations. For the stations located in the centre of the area, this variation is weaker, which we assume to be the signature of the main tectonic suture in the area (i.e. the Saxothuringian-Moldanubian suture), along a west-to-east extended region, may be due to the presence of the allochthonous klippe trapped between the main crustal terrains that came in touch during the Variscan orogeny. In the lower crust we see only small variations throughout the area, at the resolution that is possible with a small temporary experiment with just 10 stations.

Evaluation of the Klobuchar model in TaiWan

NASA Astrophysics Data System (ADS)

Li, Jinghua; Wan, Qingtao; Ma, Guanyi; Zhang, Jie; Wang, Xiaolan; Fan, Jiangtao

2017-09-01

Ionospheric delay is the mainly error source in Global Navigation Satellite System (GNSS). Ionospheric model is one of the ways to correct the ionospheric delay. The single-frequency GNSS users modify the ionospheric delay by receiving the correction parameters broadcasted by satellites. Klobuchar model is widely used in Global Positioning System (GPS) and COMPASS because it is simple and convenient for real-time calculation. This model is established on the observations mainly from Europe and USA. It does not describe the equatorial anomaly region. South of China is located near the north crest of the equatorial anomaly, where the ionosphere has complex spatial and temporal variation. The assessment on the validation of Klobuchar model in this area is important to improve this model. Eleven years (2003-2014) data from one GPS receiver located at Taoyuan Taiwan (121°E, 25°N) are used to assess the validation of Klobuchar model in Taiwan. Total electron content (TEC) from the dual-frequency GPS observations is calculated and used as the reference, and TEC based on the Klobuchar model is compared with the reference. The residual is defined as the difference between the TEC from Klobuchar model and the reference. It is a parameter to reflect the absolute correction of the model. RMS correction percentage presents the validation of the model relative to the observations. The residuals' long-term variation, the RMS correction percentage, and their changes with the latitudes are analyzed respectively to access the model. In some months the RMS correction did not reach the goal of 50% purposed by Klobuchar, especially in the winter of the low solar activity years and at nighttime. RMS correction did not depend on the 11-years solar activity, neither the latitudes. Different from RMS correction, the residuals changed with the solar activity, similar to the variation of TEC. The residuals were large in the daytime, during the equinox seasons and in the high solar activity years; they are small at night, during the solstice seasons, and in the low activity years. During 1300-1500 BJT in the high solar activity years, the mean bias was negative, implying the model underestimated TEC on average. The maximum mean bias was 33TECU in April 2014, and the maximum underestimation reached 97TECU in October 2011. During 0000-0200 BJT, the residuals had small mean bias, small variation range and small standard deviation. It suggested that the model could describe the TEC of the ionosphere better than that in the daytime. Besides the variation with the solar activity, the residuals also vary with the latitudes. The means bias reached the maximum at 20-22°N, corresponding to the north crest of the equatorial anomaly. At this latitude, the maximum mean bias was 47TECU lower than the observation in the high activity years, and 12TECU lower in the low activity years. The minimum variation range appeared at 30-32°N in high and low activity years. But the minimum mean bias was at different latitudes in the high and low activity years. In the high activity years, it appeared at 30-32°N, and in the low years it was at 24-26°N. For an ideal model, the residuals should have small mean bias and small variation range. Further study is needed to learn the distribution of the residuals and to improve the model.

Neutral particle beam sensing and steering

DOEpatents

Maier, II, William B.; Cobb, Donald D.; Robiscoe, Richard T.

1991-01-01

The direction of a neutral particle beam (NPB) is determined by detecting Ly.alpha. radiation emitted during motional quenching of excited H(2S) atoms in the beam during movement of the atoms through a magnetic field. At least one detector is placed adjacent the beam exit to define an optical axis that intercepts the beam at a viewing angle to include a volume generating a selected number of photons for detection. The detection system includes a lens having an area that is small relative to the NPB area and a pixel array located in the focal plane of the lens. The lens viewing angle and area pixel array are selected to optimize the beam tilt sensitivity. In one embodiment, two detectors are placed coplanar with the beam axis to generate a difference signal that is insensitive to beam variations other than beam tilt.

Multiscale 3D Shape Analysis using Spherical Wavelets

PubMed Central

Nain, Delphine; Haker, Steven; Bobick, Aaron; Tannenbaum, Allen

2013-01-01

Shape priors attempt to represent biological variations within a population. When variations are global, Principal Component Analysis (PCA) can be used to learn major modes of variation, even from a limited training set. However, when significant local variations exist, PCA typically cannot represent such variations from a small training set. To address this issue, we present a novel algorithm that learns shape variations from data at multiple scales and locations using spherical wavelets and spectral graph partitioning. Our results show that when the training set is small, our algorithm significantly improves the approximation of shapes in a testing set over PCA, which tends to oversmooth data. PMID:16685992

Multiscale 3D shape analysis using spherical wavelets.

PubMed

Nain, Delphine; Haker, Steven; Bobick, Aaron; Tannenbaum, Allen R

2005-01-01

Shape priors attempt to represent biological variations within a population. When variations are global, Principal Component Analysis (PCA) can be used to learn major modes of variation, even from a limited training set. However, when significant local variations exist, PCA typically cannot represent such variations from a small training set. To address this issue, we present a novel algorithm that learns shape variations from data at multiple scales and locations using spherical wavelets and spectral graph partitioning. Our results show that when the training set is small, our algorithm significantly improves the approximation of shapes in a testing set over PCA, which tends to oversmooth data.

Human impact in naturally patched small populations: genetic structure and conservation of the burrowing rodent, tuco-tuco (Ctenomys lami).

PubMed

Lopes, Carla M; de Freitas, Thales R O

2012-01-01

Isolated or semi-isolated small populations are commonly found among species, due to a naturally patchy occupancy of suitable habitats or also as a result of habitat alterations. These populations are subject to an increased risk of local extinction because they are more vulnerable to demographic, genetic, and environmental stochasticity. Considering that natural areas have been becoming progressively more fragmented and smaller, understanding the genetic structure and evolutionary dynamics of small populations is critical. Ctenomys lami has 26 karyotypes distributed in a small area (936 km(2)) continually modified by human actions. We assessed the genetic geographical structure of this species, examining 178 specimens sampled on a fine scale, using information from chromosomal variability, mitochondrial DNA control region and cytochrome c oxidase subunit I sequences, and 14 microsatellite loci. The observed isolation-by-distance pattern and a clinal genetic variation suggest a stepping-stone population model. The results did not indicate genetic structuring associated with distinct karyotypes. However, mitochondrial and nuclear molecular markers demonstrated the existence of 2 demes, which are not completely isolated but are probably reinforced by a geographical barrier. The vulnerability of C. lami is greater than previously supposed, and our data support the designation of one Evolutionary Significant Unit and one Management Unit, and also the inclusion of this species' conservation status as vulnerable.

Variations in the structure of nexuses in the myocardium of the golden hamster Mesocricetus auratus.

PubMed Central

Skepper, J N; Navaratnam, V

1986-01-01

The structure of nexuses in the atrioventricular node of the golden hamster was studied with the transmission electron microscope, using thin sections and freeze-fracture replicas, and was compared with that of nexuses in the working myocardium of the right ventricular wall. Whereas ventricular myocardium contained macular nexuses only, nodal tissue contained annular and linear configurations as well as maculae of varying size. The significance of such variations in nexus pattern is not clear although several hypotheses are discussed in the literature. Measurements made on electron micrographs, after allowing for tilt of the specimen, yielded a particle diameter of 10.59 nm for nodal myocardium and 10.95 nm for ventricular myocardium, both measurements being substantially higher than figures generally cited in the literature. In each area the measurements had a normal distribution suggesting a single type of particle. The small but significant difference in particle size between the two areas is more likely to be caused by dissimilarities in packing arrangement rather than by differences in intrinsic structure or in functional state. Images Fig. 1 Fig. 3 PMID:3693102

Shuttle Imaging Radar (SIR-B) investigations of the Canadian shield - Initial Report

NASA Technical Reports Server (NTRS)

Lowman, Paul D., Jr.; Harris, Jeff; Masuoka, Penny M.; Singhroy, Vernon H.; Slaney, Vernon Roy

1987-01-01

Two of the 43 Shuttle Imaging Radar (SIR-B) experiments carried out from the 41-G shuttle mission in 1984 involved a 2600-km swath across the Canadian Shield, with the objectives of studying the structure of province boundaries and developing techniques for the geologic use of orbital radar. Despite degraded single incidence angle imagery resulting from system problems, valuable experience has been obtained with data over a test site near Bancroft, Ontario. It has been found that even subdued glaciated topography can be effectively imaged, variations in backscatter being caused by variations in local incidence angle rather than shadowing. It has been demonstrated that small incidence angles are more sensitive to topography than large angles. Backscatter is extremely sensitive to look direction, topographic features nearly normal to the illumination being highlighted, and those nearly parallel to it being suppressed. It is concluded that orbital radar can provide a valuable tool for geologic studies of the Canadian Shield and similar areas, if suitable look angles and at least two look directions can be utilized for each area.

Transport of particle-associated elements in two agriculture-dominated boreal river systems.

PubMed

Marttila, Hannu; Saarinen, Tuomas; Celebi, Ahmet; Kløve, Bjørn

2013-09-01

Transport of particulate pollutants in fluvial systems can contribute greatly to total loads. Understanding transport mechanics under different hydrological conditions is key in successful load estimation. This study analysed trace elements and physico-chemical parameters in time-integrated suspended sediment samples, together with dissolved and total concentrations of pollutants, along two agriculture- and peatland-dominated boreal river systems. The samples were taken in a spatially and temporally comprehensive sampling programme during the ice-free seasons of 2010 and 2011. The hydrochemistry and transport of particle-bound elements in the rivers were strongly linked to intense land use and acid sulphate soils in the catchment area, with arable, pasture and peat areas in particular being main diffuse sources. There were significant seasonal and temporal variations in dissolved and particulate fluxes, but spatial variations were small. Continuous measurements of EC, turbidity and discharge proved to be an accurate indicator of dissolved and particulate fluxes. Overall, the results show that transport of particle-bound elements makes a major contribution to total transport fluxes in agriculture-dominated boreal rivers. Copyright © 2013 Elsevier B.V. All rights reserved.

Response of Water Use Efficiency to Global Environmental Change Based on Output From Terrestrial Biosphere Models

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

Zhou, Sha; Yu, Bofu; Schwalm, Christopher R.

Here, water use efficiency (WUE), defined as the ratio of gross primary productivity and evapotranspiration at the ecosystem scale, is a critical variable linking the carbon and water cycles. Incorporating a dependency on vapor pressure deficit, apparent underlying WUE (uWUE) provides a better indicator of how terrestrial ecosystems respond to environmental changes than other WUE formulations. Here we used 20th century simulations from four terrestrial biosphere models to develop a novel variance decomposition method. With this method, we attributed variations in apparent uWUE to both the trend and interannual variation of environmental drivers. The secular increase in atmospheric CO 2more » explained a clear majority of total variation (66 ± 32%: mean ± one standard deviation), followed by positive trends in nitrogen deposition and climate, as well as a negative trend in land use change. In contrast, interannual variation was mostly driven by interannual climate variability. To analyze the mechanism of the CO 2 effect, we partitioned the apparent uWUE into the transpiration ratio (transpiration over evapotranspiration) and potential uWUE. The relative increase in potential uWUE parallels that of CO 2, but this direct CO 2 effect was offset by 20 ± 4% by changes in ecosystem structure, that is, leaf area index for different vegetation types. However, the decrease in transpiration due to stomatal closure with rising CO 2 was reduced by 84% by an increase in leaf area index, resulting in small changes in the transpiration ratio. CO 2 concentration thus plays a dominant role in driving apparent uWUE variations over time, but its role differs for the two constituent components: potential uWUE and transpiration.« less

Spatial variation and seasonal dynamics of leaf-area index in the arctic tundra-implications for linking ground observations and satellite images

NASA Astrophysics Data System (ADS)

Juutinen, Sari; Virtanen, Tarmo; Kondratyev, Vladimir; Laurila, Tuomas; Linkosalmi, Maiju; Mikola, Juha; Nyman, Johanna; Räsänen, Aleksi; Tuovinen, Juha-Pekka; Aurela, Mika

2017-09-01

Vegetation in the arctic tundra typically consists of a small-scale mosaic of plant communities, with species differing in growth forms, seasonality, and biogeochemical properties. Characterization of this variation is essential for understanding and modeling the functioning of the arctic tundra in global carbon cycling, as well as for evaluating the resolution requirements for remote sensing. Our objective was to quantify the seasonal development of the leaf-area index (LAI) and its variation among plant communities in the arctic tundra near Tiksi, coastal Siberia, consisting of graminoid, dwarf shrub, moss, and lichen vegetation. We measured the LAI in the field and used two very-high-spatial resolution multispectral satellite images (QuickBird and WorldView-2), acquired at different phenological stages, to predict landscape-scale patterns. We used the empirical relationships between the plant community-specific LAI and degree-day accumulation (0 °C threshold) and quantified the relationship between the LAI and satellite NDVI (normalized difference vegetation index). Due to the temporal difference between the field data and satellite images, the LAI was approximated for the imagery dates, using the empirical model. LAI explained variation in the NDVI values well (R 2 adj. 0.42-0.92). Of the plant functional types, the graminoid LAI showed the largest seasonal amplitudes and was the main cause of the varying spatial patterns of the NDVI and the related LAI between the two images. Our results illustrate how the short growing season, rapid development of the LAI, yearly climatic variation, and timing of the satellite data should be accounted for in matching imagery and field verification data in the Arctic region.

Adjusting for geographic variation in observational comparative effectiveness studies: a case study of antipsychotics using state Medicaid data.

PubMed

Root, Elisabeth Dowling; Thomas, Deborah S K; Campagna, Elizabeth J; Morrato, Elaine H

2014-08-27

Area-level variation in treatment and outcomes may be a potential source of confounding bias in observational comparative effectiveness studies. This paper demonstrates how to use exploratory spatial data analysis (ESDA) and spatial statistical methods to investigate and control for these potential biases. The case presented compares the effectiveness of two antipsychotic treatment strategies: oral second-generation antipsychotics (SGAs) vs. long-acting paliperiodone palmitate (PP). A new-start cohort study was conducted analyzing patient-level administrative claims data (8/1/2008-4/30/2011) from Missouri Medicaid. ESDA techniques were used to examine spatial patterns of antipsychotic prescriptions and outcomes (hospitalization and emergency department (ED) visits). Likelihood of mental health-related outcomes were compared between patients starting PP (N = 295) and oral SGAs (N = 8,626) using multilevel logistic regression models adjusting for patient composition (demographic and clinical factors) and geographic region. ESDA indicated significant spatial variation in antipsychotic prescription patterns and moderate variation in hospitalization and ED visits thereby indicating possible confounding by geography. In the multilevel models for this antipsychotic case example, patient composition represented a stronger source of confounding than geographic context. Because geographic variation in health care delivery is ubiquitous, it could be a comparative effectiveness research (CER) best practice to test for possible geographic confounding in observational data. Though the magnitude of the area-level geography effects were small in this case, they were still statistically significant and should therefore be examined as part of this observational CER study. More research is needed to better estimate the range of confounding due to geography across different types of observational comparative effectiveness studies and healthcare utilization outcomes.

Lateral variations of the Guerrero-Oaxaca subduction zone (Mexico) derived from weak seismicity (Mb3.5+) detected on a single array at teleseismic distance

NASA Astrophysics Data System (ADS)

Letort, Jean; Retailleau, Lise; Boué, Pierre; Radiguet, Mathilde; Gardonio, Blandine; Cotton, Fabrice; Campillo, Michel

2018-05-01

Detections of pP and sP phase arrivals (the so-called depth phases) at teleseismic distance provide one of the best ways to estimate earthquake focal depth, as the P-pP and the P-sP delays are strongly dependent on the depth. Based on a new processing workflow and using a single seismic array at teleseismic distance, we can estimate the depth of clusters of small events down to magnitude Mb 3.5. Our method provides a direct view of the relative variations of the seismicity depth from an active area. This study focuses on the application of this new methodology to study the lateral variations of the Guerrero subduction zone (Mexico) using the Eielson seismic array in Alaska (USA). After denoising the signals, 1232 Mb 3.5 + events were detected, with clear P, pP, sP and PcP arrivals. A high-resolution view of the lateral variations of the depth of the seismicity of the Guerero-Oaxaca area is thus obtained. The seismicity is shown to be mainly clustered along the interface, coherently following the geometry of the plate as constrained by the receiver-function analysis along the Meso America Subduction Experiment profile. From this study, the hypothesis of tears on the western part of Guerrero and the eastern part of Oaxaca are strongly confirmed by dramatic lateral changes in the depth of the earthquake clusters. The presence of these two tears might explain the observed lateral variations in seismicity, which is correlated with the boundaries of the slow slip events.

Response of Water Use Efficiency to Global Environmental Change Based on Output From Terrestrial Biosphere Models

NASA Astrophysics Data System (ADS)

Zhou, Sha; Yu, Bofu; Schwalm, Christopher R.; Ciais, Philippe; Zhang, Yao; Fisher, Joshua B.; Michalak, Anna M.; Wang, Weile; Poulter, Benjamin; Huntzinger, Deborah N.; Niu, Shuli; Mao, Jiafu; Jain, Atul; Ricciuto, Daniel M.; Shi, Xiaoying; Ito, Akihiko; Wei, Yaxing; Huang, Yuefei; Wang, Guangqian

2017-11-01

Water use efficiency (WUE), defined as the ratio of gross primary productivity and evapotranspiration at the ecosystem scale, is a critical variable linking the carbon and water cycles. Incorporating a dependency on vapor pressure deficit, apparent underlying WUE (uWUE) provides a better indicator of how terrestrial ecosystems respond to environmental changes than other WUE formulations. Here we used 20th century simulations from four terrestrial biosphere models to develop a novel variance decomposition method. With this method, we attributed variations in apparent uWUE to both the trend and interannual variation of environmental drivers. The secular increase in atmospheric CO2 explained a clear majority of total variation (66 ± 32%: mean ± one standard deviation), followed by positive trends in nitrogen deposition and climate, as well as a negative trend in land use change. In contrast, interannual variation was mostly driven by interannual climate variability. To analyze the mechanism of the CO2 effect, we partitioned the apparent uWUE into the transpiration ratio (transpiration over evapotranspiration) and potential uWUE. The relative increase in potential uWUE parallels that of CO2, but this direct CO2 effect was offset by 20 ± 4% by changes in ecosystem structure, that is, leaf area index for different vegetation types. However, the decrease in transpiration due to stomatal closure with rising CO2 was reduced by 84% by an increase in leaf area index, resulting in small changes in the transpiration ratio. CO2 concentration thus plays a dominant role in driving apparent uWUE variations over time, but its role differs for the two constituent components: potential uWUE and transpiration.

Reserve size and fragmentation alter community assembly, diversity, and dynamics.

PubMed

Lasky, Jesse R; Keitt, Timothy H

2013-11-01

Researchers have disputed whether a single large habitat reserve will support more species than many small reserves. However, relatively little is known from a theoretical perspective about how reserve size affects competitive communities structured by spatial abiotic gradients. We investigate how reserve size affects theoretical communities whose assembly is governed by dispersal limitation, abiotic niche differentiation, and source-sink dynamics. Simulations were conducted with varying scales of dispersal across landscapes with variable environmental spatial autocorrelation. Landscapes were inhabited by simulated trees with seedling and adult stages. For a fixed total area in reserves, we found that small reserve systems increased the distance between environments dominated by different species, diminishing the effects of source-sink dynamics. As reserve size decreased, environmental limitations to community assembly became stronger, α species richness decreased, and γ richness increased. When dispersal occurred across short distances, a large reserve strategy caused greater stochastic community variation, greater α richness, and lower γ richness than in small reserve systems. We found that reserve size variation trades off between preserving different aspects of natural communities, including α diversity versus γ diversity. Optimal reserve size will depend on the importance of source-sink dynamics and the value placed on different characteristics of natural communities. Anthropogenic changes to the size and separation of remnant habitats can have far-reaching effects on community structure and assembly.

Water quality of small seasonal wetlands in the Piedmont ecoregion, South Carolina, USA: Effects of land use and hydrological connectivity.

PubMed

Yu, Xubiao; Hawley-Howard, Joanna; Pitt, Amber L; Wang, Jun-Jian; Baldwin, Robert F; Chow, Alex T

2015-04-15

Small, shallow, seasonal wetlands with short hydroperiod (2-4 months) play an important role in the entrapment of organic matter and nutrients and, due to their wide distribution, in determining the water quality of watersheds. In order to explain the temporal, spatial and compositional variation of water quality of seasonal wetlands, we collected water quality data from forty seasonal wetlands in the lower Blue Ridge and upper Piedmont ecoregions of South Carolina, USA during the wet season of February to April 2011. Results indicated that the surficial hydrological connectivity and surrounding land-use were two key factors controlling variation in dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) in these seasonal wetlands. In the sites without obvious land use changes (average developed area <0.1%), the DOC (p < 0.001, t-test) and TDN (p < 0.05, t-test) of isolated wetlands were significantly higher than that of connected wetlands. However, this phenomenon can be reversed as a result of land use changes. The connected wetlands in more urbanized areas (average developed area = 12.3%) showed higher concentrations of dissolved organic matter (DOM) (DOC: 11.76 ± 6.09 mg L(-1), TDN: 0.74 ± 0.22 mg L(-1), mean ± standard error) compared to those in isolated wetlands (DOC: 7.20 ± 0.62 mg L(-1), TDN: 0.20 ± 0.08 mg L(-1)). The optical parameters derived from UV and fluorescence also confirmed significant portions of protein-like fractions likely originating from land use changes such as wastewater treatment and livestock pastures. The average of C/N molar ratios of all the wetlands decreased from 77.82 ± 6.72 (mean ± standard error) in February to 15.14 ± 1.58 in April, indicating that the decomposition of organic matter increased with the temperature. Results of this study demonstrate that the water quality of small, seasonal wetlands has a direct and close association with the surrounding environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

A sampling procedure to guide the collection of narrow-band, high-resolution spatially and spectrally representative reflectance data. [satellite imagery of earth resources

NASA Technical Reports Server (NTRS)

Brand, R. R.; Barker, J. L.

1983-01-01

A multistage sampling procedure using image processing, geographical information systems, and analytical photogrammetry is presented which can be used to guide the collection of representative, high-resolution spectra and discrete reflectance targets for future satellite sensors. The procedure is general and can be adapted to characterize areas as small as minor watersheds and as large as multistate regions. Beginning with a user-determined study area, successive reductions in size and spectral variation are performed using image analysis techniques on data from the Multispectral Scanner, orbital and simulated Thematic Mapper, low altitude photography synchronized with the simulator, and associated digital data. An integrated image-based geographical information system supports processing requirements.

Urban stress is associated with variation in microbial species composition—but not richness—in Manhattan

PubMed Central

Reese, Aspen T; Savage, Amy; Youngsteadt, Elsa; McGuire, Krista L; Koling, Adam; Watkins, Olivia; Frank, Steven D; Dunn, Robert R

2016-01-01

The biological diversity and composition of microorganisms influences both human health outcomes and ecological processes; therefore, understanding the factors that influence microbial biodiversity is key to creating healthy, functional landscapes in which to live. In general, biological diversity is predicted to be limited by habitat size, which for green areas is often reduced in cities, and by chronic disturbance (stress). These hypotheses have not previously been tested in microbial systems in direct comparison to macroorganisms. Here we analyzed bacterial, fungal and ant communities in small road medians (average area 0.0008 km2) and larger parks (average area 0.64 km2) across Manhattan (NYC). Bacterial species richness was not significantly different between medians and parks, but community composition was significantly distinct. In contrast, ant communities differed both in composition and richness with fewer ant species in medians than parks. Fungi showed no significant variation in composition or richness but had few shared taxa between habitats or sites. The diversity and composition of microbes appears less sensitive to habitat patchiness or urban stress than those of macroorganisms. Microbes and their associated ecosystem services and functions may be more resilient to the negative effects of urbanization than has been previously appreciated. PMID:26394011

Getting (the most) out of the research business: interventions for youth with T1DM.

PubMed

Harris, Michael A; Freeman, Kurt A; Duke, Danny C

2010-12-01

We review research on psychosocial interventions to improve outcomes for youth with type 1 diabetes mellitus. Specifically, we discuss individual- and small group-focused, family-focused, group-focused, and other interventions. After reviewing extant research in each area, we discuss how the current evidence base may be used to inform clinical practice. Finally, we conclude by discussing variations in effects of interventions on different outcomes (eg, glycemic control, family functioning) and how to consider this evidence when selecting treatments to transport into clinical settings.

Coping styles of Chicago adults: description.

PubMed

Ilfeld, F W

1980-01-01

Drawing upon a sample of 2,299 Chicago adults the author empirically describes the coping styles used to combat stressors in the social roles of marriage, parenting, finances, and job. Factor analyses of coping responses uncovered three major patterns: taking direct action, rationalization avoidance of the stressor, and acceptance of the stressful situation without attempting alteration. Respondents did not consistently utilize one coping style across all role areas, but rather employed a repertoire of responses. Demographic characteristics were found to explain only a small amount of variation in the coping styles.

Pharmacokinetic Variability of Drugs Used for Prophylactic Treatment of Migraine.

PubMed

Tfelt-Hansen, Peer; Ågesen, Frederik Nybye; Pavbro, Agniezka; Tfelt-Hansen, Jacob

2017-05-01

In this review, we evaluate the variability in the pharmacokinetics of 11 drugs with established prophylactic effects in migraine to facilitate 'personalized medicine' with these drugs. PubMed was searched for 'single-dose' and 'steady-state' pharmacokinetic studies of these 11 drugs. The maximum plasma concentration was reported in 248 single-dose and 115 steady-state pharmacokinetic studies, and the area under the plasma concentration-time curve was reported in 299 single-dose studies and 112 steady-state pharmacokinetic studies. For each study, the coefficient of variation was calculated for maximum plasma concentration and area under the plasma concentration-time curve, and we divided the drug variability into two categories; high variability, coefficient of variation >40%, or low or moderate variability, coefficient of variation <40%. Based on the area under the plasma concentration-time curve in steady-state studies, the following drugs have high pharmacokinetic variability: propranolol in 92% (33/36), metoprolol in 85% (33/39), and amitriptyline in 60% (3/5) of studies. The following drugs have low or moderate variability: atenolol in 100% (2/2), valproate in 100% (15/15), topiramate in 88% (7/8), and naproxen and candesartan in 100% (2/2) of studies. For drugs with low or moderate pharmacokinetic variability, treatment can start without initial titration of doses, whereas titration is used to possibly enhance tolerability of topiramate and amitriptyline. The very high pharmacokinetic variability of metoprolol and propranolol can result in very high plasma concentrations in a small minority of patients, and those drugs should therefore be titrated up from a low initial dose, depending mainly on the occurrence of adverse events.

[A valid quality system for mental health care: from accountability and control in institutionalised settings to co-creation in small areas and a focus on community vital signs].

PubMed

van Os, J; Delespaul, P H

In a given year, around 25% of the Dutch population may experience significant mental health problems, much more than the mental health service can attend to, given a maximum capacity of 6% of the population per year. Due to the lack of a public mental health system, there is fierce competition over who gets to receive care from mental health services and little control over how the level of needs can be matched with the appropriate intensity of care. As a result, resources are being wasted and both overtreatment and undertreatment are prevalent.
AIM: To propose a valid quality system that benefits the mental health of the entire population and does not simply attend to the symptoms of a strategically selected group.
METHOD: Literature review from an epidemiological and public mental health perspective.
RESULTS: In our view, a valid quality system for mental health care needs to focus on two distinct areas. The first area involves the analysis of about 20 quantitative population parameters or 'Community Vital Signs' (care consumption, pharmaco-epidemiological indicators, mortality, somatic morbidity, social care, housing, work, benefits, involuntary admissions). This analysis will reveal regional variation in the mental health of the entire population rather than in the relatively small, selected group receiving mental health care. The second area to which attention needs to be directed comprises a system of simple qualitative visits to mental health care institutions based on 10 quality parameters that currently remain invisible; these parameters will measure the impact at local community level. The focus of these will be on a transition from accountability and control in large institutions to provision of care in small areas that was co-designed with users and other stakeholders.
CONCLUSION: A valid quality system for mental health care is within reach, provided it is combined with a novel system of public mental health and transition of care to a system of co-design with users in small areas.

Population ecology of the mallard VIII: Winter distribution patterns and survival rates of winter-banded mallards

USGS Publications Warehouse

Nichols, James D.; Hines, James E.

1987-01-01

In the present report we address questions about winter distribution patterns and survival rates of North American mallards Anas platyrhynchos. Inferences are based on analyses of banding and recovery data from both winter and preseason banding period. The primary wintering range of the mallard was dividded into 45 minor reference areas and 15 major reference areas which were used to summarize winter banding data. Descriptive tables and figures on the recovery distributions of winter-banded mallards are presented. Using winter recoveries of preseason-banded mallards, we found apparent differences between recovery distribution of young versus adult birds from the same breeding ground reference areas. However, we found no sex-specific differences in winter recovery distribution patterns. Winter recovery distributions of preseason-banded birds also provided evidence that mallards exhibited some degree of year-to-year variation in wintering ground location. The age- and sex-specificity of such variation was tested using winter recoveries of winter-banded birds, and results indicated that subadult (first year) birds were less likely to return to the same wintering grounds the following year than adults. Winter recovery distributions of preseason-banded mallards during 1950-58 differed from distributions in 1966-76. These differences could have resulted from either true distributional shifts or geographic changes in hunting pressure. Survival and recovery rates were estimated from winter banding data. We found no evidence of differences in survival or recovery rates between subadult and adult mallards. Thus, the substantial difference between survival rates of preseason-banded young and adult mallards must result almost entirely from higher mortality of young birds during the approximate period, August-January. Male mallards showed higher survival than females, corroborating inferences based on preseason data. Tests with winter banding and band recovery data indicated some degree of year-to-year variation in both survival and recovery rates, a result again consistent with inference from preseason data. Some evidence indication geographic variation in survival rates; however, there were no consistent directional differences between survival rates of mallards from adjacent northern versus southern areas, or eastern versus western areas. In some comparisons, Central Flyway mallards exhibited slightly higher survival rates than mallards from other flyways. Weighted mean estimates of continental survival rates were computed for the period 1960-77 from both winter banding data and preseason banding of adults. Resulting estimates differed significantly for males, but not for females, and the magnitude of the difference between point estimates was relatively small, even for males. The direction of the difference between these estimates was predicted correctly from previous work on the effects of heterogeneous survival an d recovery rates on band recovery model estimates. The similarity of survival estimates from these two independent data sets supports the believe that biases in these estimates are relatively small.

A BAYESIAN SPATIAL AND TEMPORAL MODELING APPROACH TO MAPPING GEOGRAPHIC VARIATION IN MORTALITY RATES FOR SUBNATIONAL AREAS WITH R-INLA.

PubMed

Khana, Diba; Rossen, Lauren M; Hedegaard, Holly; Warner, Margaret

2018-01-01

Hierarchical Bayes models have been used in disease mapping to examine small scale geographic variation. State level geographic variation for less common causes of mortality outcomes have been reported however county level variation is rarely examined. Due to concerns about statistical reliability and confidentiality, county-level mortality rates based on fewer than 20 deaths are suppressed based on Division of Vital Statistics, National Center for Health Statistics (NCHS) statistical reliability criteria, precluding an examination of spatio-temporal variation in less common causes of mortality outcomes such as suicide rates (SRs) at the county level using direct estimates. Existing Bayesian spatio-temporal modeling strategies can be applied via Integrated Nested Laplace Approximation (INLA) in R to a large number of rare causes of mortality outcomes to enable examination of spatio-temporal variations on smaller geographic scales such as counties. This method allows examination of spatiotemporal variation across the entire U.S., even where the data are sparse. We used mortality data from 2005-2015 to explore spatiotemporal variation in SRs, as one particular application of the Bayesian spatio-temporal modeling strategy in R-INLA to predict year and county-specific SRs. Specifically, hierarchical Bayesian spatio-temporal models were implemented with spatially structured and unstructured random effects, correlated time effects, time varying confounders and space-time interaction terms in the software R-INLA, borrowing strength across both counties and years to produce smoothed county level SRs. Model-based estimates of SRs were mapped to explore geographic variation.

Mercury content of the Springfield coal, Indiana and Kentucky

USGS Publications Warehouse

Hower, J.C.; Mastalerz, Maria; Drobniak, A.; Quick, J.C.; Eble, C.F.; Zimmerer, M.J.

2005-01-01

With pending regulation of mercury emissions in United States power plants, its control at every step of the combustion process is important. An understanding of the amount of mercury in coal at the mine is the first step in this process. The Springfield coal (Middle Pennsylvanian) is one of the most important coal resources in the Illinois Basin. In Indiana and western Kentucky, Hg contents range from 0.02 to 0.55 ppm. The variation within small areas is comparable to the variation on a basin basis. Considerable variation also exists within the coal column, ranging from 0.04 to 0.224 ppm at one Kentucky site. Larger variations likely exist, since that site does not represent the highest whole-seam Hg nor was the collection of samples done with optimization of trace element variations in mind. Estimates of Hg capture by currently installed pollution control equipment range from 9-53% capture by cold-side electrostatic precipitators (ESP) and 47-81% Hg capture for ESP + flue-gas desulfurization (FGD). The high Cl content of many Illinois basin coals and the installation of Selective Catalytic Reduction of NOx enhances the oxidation of Hg species, improving the ability of ESPs and FGDs to capture Hg. ?? 2005 Elsevier B.V. All rights reserved.

A southern Africa harmonic spline core field model derived from CHAMP satellite data

NASA Astrophysics Data System (ADS)

Nahayo, E.; Kotzé, P. B.; McCreadie, H.

2015-02-01

The monitoring of the Earth's magnetic field time variation requires a continuous recording of geomagnetic data with a good spatial coverage over the area of study. In southern Africa, ground recording stations are limited and the use of satellite data is needed for the studies where high spatial resolution data is required. We show the fast time variation of the geomagnetic field in the southern Africa region by deriving an harmonic spline model from CHAMP satellite measurements recorded between 2001 and 2010. The derived core field model, the Southern Africa Regional Model (SARM), is compared with the global model GRIMM-2 and the ground based data recorded at Hermanus magnetic observatory (HER) in South Africa and Tsumeb magnetic observatory (TSU) in Namibia where the focus is mainly on the long term variation of the geomagnetic field. The results of this study suggest that the regional model derived from the satellite data alone can be used to study the small scale features of the time variation of the geomagnetic field where ground data is not available. In addition, these results also support the earlier findings of the occurrence of a 2007 magnetic jerk and rapid secular variation fluctuations of 2003 and 2004 in the region.

Test system stability and natural variability of a Lemna gibba L. bioassay.

PubMed

Scherr, Claudia; Simon, Meinhard; Spranger, Jörg; Baumgartner, Stephan

2008-09-04

In ecotoxicological and environmental studies Lemna spp. are used as test organisms due to their small size, rapid predominantly vegetative reproduction, easy handling and high sensitivity to various chemicals. However, there is not much information available concerning spatial and temporal stability of experimental set-ups used for Lemna bioassays, though this is essential for interpretation and reliability of results. We therefore investigated stability and natural variability of a Lemna gibba bioassay assessing area-related and frond number-related growth rates under controlled laboratory conditions over about one year. Lemna gibba L. was grown in beakers with Steinberg medium for one week. Area-related and frond number-related growth rates (r(area) and r(num)) were determined with a non-destructive image processing system. To assess inter-experimental stability, 35 independent experiments were performed with 10 beakers each in the course of one year. We observed changes in growth rates by a factor of two over time. These did not correlate well with temperature or relative humidity in the growth chamber. In order to assess intra-experimental stability, we analysed six systematic negative control experiments (nontoxicant tests) with 96 replicate beakers each. Evaluation showed that the chosen experimental set-up was stable and did not produce false positive results. The coefficient of variation was lower for r(area) (2.99%) than for r(num) (4.27%). It is hypothesised that the variations in growth rates over time under controlled conditions are partly due to endogenic periodicities in Lemna gibba. The relevance of these variations for toxicity investigations should be investigated more closely. Area-related growth rate seems to be more precise as non-destructive calculation parameter than number-related growth rate. Furthermore, we propose two new validity criteria for Lemna gibba bioassays: variability of average specific and section-by-section segmented growth rate, complementary to average specific growth rate as the only validity criterion existing in guidelines for duckweed bioassays.

Test System Stability and Natural Variability of a Lemna Gibba L. Bioassay

PubMed Central

Scherr, Claudia; Simon, Meinhard; Spranger, Jörg; Baumgartner, Stephan

2008-01-01

Background In ecotoxicological and environmental studies Lemna spp. are used as test organisms due to their small size, rapid predominantly vegetative reproduction, easy handling and high sensitivity to various chemicals. However, there is not much information available concerning spatial and temporal stability of experimental set-ups used for Lemna bioassays, though this is essential for interpretation and reliability of results. We therefore investigated stability and natural variability of a Lemna gibba bioassay assessing area-related and frond number-related growth rates under controlled laboratory conditions over about one year. Methology/Principal Findings Lemna gibba L. was grown in beakers with Steinberg medium for one week. Area-related and frond number-related growth rates (r(area) and r(num)) were determined with a non-destructive image processing system. To assess inter-experimental stability, 35 independent experiments were performed with 10 beakers each in the course of one year. We observed changes in growth rates by a factor of two over time. These did not correlate well with temperature or relative humidity in the growth chamber. In order to assess intra-experimental stability, we analysed six systematic negative control experiments (nontoxicant tests) with 96 replicate beakers each. Evaluation showed that the chosen experimental set-up was stable and did not produce false positive results. The coefficient of variation was lower for r(area) (2.99%) than for r(num) (4.27%). Conclusions/Significance It is hypothesised that the variations in growth rates over time under controlled conditions are partly due to endogenic periodicities in Lemna gibba. The relevance of these variations for toxicity investigations should be investigated more closely. Area-related growth rate seems to be more precise as non-destructive calculation parameter than number-related growth rate. Furthermore, we propose two new validity criteria for Lemna gibba bioassays: variability of average specific and section-by-section segmented growth rate, complementary to average specific growth rate as the only validity criterion existing in guidelines for duckweed bioassays. PMID:18769541

Characteristics of small areas with high rates of hospital-treated self-harm: deprived, fragmented and urban or just close to hospital? A national registry study.

PubMed

O'Farrell, I B; Corcoran, P; Perry, I J

2015-02-01

Previous research has shown an inconsistent relationship between the spatial distribution of hospital treated self-harm and area-level factors such as deprivation and social fragmentation. However, many of these studies have been confined to urban centres, with few focusing on rural settings and even fewer studies carried out at a national level. Furthermore, no previous research has investigated if travel time to hospital services can explain the area-level variation in the incidence of hospital treated self-harm. From 2009 to 2011, the Irish National Registry of Deliberate Self Harm collected data on self-harm presentations to all hospital emergency departments in the country. The Registry uses standard methods of case ascertainment and also geocodes patient addresses to small area geographical level. Negative binomial regression was used to explore the ecological relationship between area-level self-harm rates and various area-level factors. Deprivation, social fragmentation and population density had a positive linear association with self-harm, with deprivation having the strongest independent effect. Furthermore, self-harm incidence was found to be elevated in areas that had shorter journey times to hospital. However, while this association became attenuated after controlling for other area-level factors it still remained statistically significant. A subgroup analysis examining the effect of travel time on specific methods of self-harm, found that this effect was most marked for self-harm acts involving minor self-cutting. Self-harm incidence was influenced by proximity to hospital services, population density and social fragmentation; however, the strongest area-level predictor of self-harm was deprivation. 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.

Where does good quality qualitative health care research get published?

PubMed

Richardson, Jane C; Liddle, Jennifer

2017-09-01

This short report aims to give some insight into current publication patterns for high-quality qualitative health research, using the Research Excellence Framework (REF) 2014 database. We explored patterns of publication by range and type of journal, by date and by methodological focus. We also looked at variations between the publications submitted to different Units of Assessment, focussing particularly on the one most closely aligned with our own research area of primary care. Our brief analysis demonstrates that general medical/health journals with high impact factors are the dominant routes of publication, but there is variation according to the methodological approach adopted by articles. The number of qualitative health articles submitted to REF 2014 overall was small, and even more so for articles based on mixed methods research, qualitative methodology or reviews/syntheses that included qualitative articles.

Helicopter Flight Procedures for Community Noise Reduction

NASA Technical Reports Server (NTRS)

Greenwood, Eric

2017-01-01

A computationally efficient, semiempirical noise model suitable for maneuvering flight noise prediction is used to evaluate the community noise impact of practical variations on several helicopter flight procedures typical of normal operations. Turns, "quick-stops," approaches, climbs, and combinations of these maneuvers are assessed. Relatively small variations in flight procedures are shown to cause significant changes to Sound Exposure Levels over a wide area. Guidelines are developed for helicopter pilots intended to provide effective strategies for reducing the negative effects of helicopter noise on the community. Finally, direct optimization of flight trajectories is conducted to identify low noise optimal flight procedures and quantify the magnitude of community noise reductions that can be obtained through tailored helicopter flight procedures. Physically realizable optimal turns and approaches are identified that achieve global noise reductions of as much as 10 dBA Sound Exposure Level.

The effect of urban street gang densities on small area homicide incidence in a large metropolitan county, 1994-2002.

PubMed

Robinson, Paul L; Boscardin, W John; George, Sheba M; Teklehaimanot, Senait; Heslin, Kevin C; Bluthenthal, Ricky N

2009-07-01

The presence of street gangs has been hypothesized as influencing overall levels of violence in urban communities through a process of gun-drug diffusion and cross-type homicide. This effect is said to act independently of other known correlates of violence, i.e., neighborhood poverty. To test this hypothesis, we independently assessed the impact of population exposure to local street gang densities on 8-year homicide rates in small areas of Los Angeles County, California. Homicide data from the Los Angeles County Coroners Office were analyzed with original field survey data on street gang locations, while controlling for the established covariates of community homicide rates. Bivariate and multivariate regression analyses explicated strong relationships between homicide rates, gang density, race/ethnicity, and socioeconomic structure. Street gang densities alone had cumulative effects on small area homicide rates. Local gang densities, along with high school dropout rates, high unemployment rates, racial and ethnic concentration, and higher population densities, together explained 90% of the variation in local 8-year homicide rates. Several other commonly considered covariates were insignificant in the model. Urban environments with higher densities of street gangs exhibited higher overall homicide rates, independent of other community covariates of homicide. The unique nature of street gang killings and their greater potential to influence future local rates of violence suggests that more direct public health interventions are needed alongside traditional criminal justice mechanisms to combat urban violence and homicides.

Crystal growth mechanisms in miarolitic cavities in the Lake George ring complex and vicinity, Colorado

USGS Publications Warehouse

Kile, D.E.; Eberl, D.D.

1999-01-01

The Crystal Peak area of the Pikes Peak batholith, near Lake George in central Colorado, is world-renowned for its crystals of amazonite (the blue-green variety of microcline) and smoky quartz. Such crystals, collected from individual miarolitic pegmatites, have a remakably small variation in crystal size within each pegmatite, and the shapes of plots of their crystal size distributions (CSDs) are invariably lognormal or close to lognormal in all cases. These observations are explained by a crystal growth mechanism that was governed initially by surface-controlled kinetics, during which crystals tended to grow larger in proportion to their size, thereby establishing lognormal CSDs. Surface-controlled growth was followed by longer periods of supply controlled growth, during which growth rate was predominantly size-independent, consequently preserving the lognormal shapes of the CSDs and the small size variation. The change from surface- to supply controlled growth kinetics may have resulted from an increasing demand for nutrients that exceeded diffusion limitations of the system. The proposed model for crystal growth in this locality appears to be common in the geologic record, and can be used with other information, such as isotopic data, to deduce physico-chemical conditions during crystal formation.

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

White, J.D.L.; Robinson, P.T.

The largely Eocene Clarno Formation consists of andesitic volcaniclastic rocks interstratified with clayey paludal sediments and lava flows, and cut locally by irregular hypabyssal stocks, dikes and sills. Lateral lithofacies variations are pronounced, and intrusive and extrusive volcanic rocks appear haphazardly emplaced throughout the formation. A range of sedimentary environments is represented, including near-vent flow and breccia accumulations, bouldery high-gradient braided streams, and relatively low-gradient sandy-tuff braidplains associated with paludal deposits. The authors infer that the coarse-grained volcaniclastic rocks of the Clarno Formation accumulated largely in volcanic flank and apron settings. The stratigraphy of the formation indicates that it wasmore » formed in sedimentary lowlands into which many small volcanoes erupted; only a few, scattered remnants of large central vent volcanoes are known. The absence of systematic variation across the unit's large outcrop belt argues against the derivation of the succession from a line of volcanoes beyond the reaches of the present outcrop. The authors infer that the arc was composed of small to medium-sized volcanoes arranged non-systematically over a broad area. The sedimentary succession most probably accumulated in a series of shallow intra-arc depressions formed by crustal stretching and diffuse block rotation driven by oblique subduction during the Eocene.« less

Monitoring of oceanographic properties of Glacier Bay, Alaska 2004

USGS Publications Warehouse

Madison, Erica N.; Etherington, Lisa L.

2005-01-01

Glacier Bay is a recently (300 years ago) deglaciated fjord estuarine system that has multiple sills, very deep basins, tidewater glaciers, and many streams. Glacier Bay experiences a large amount of runoff, high sedimentation, and large tidal variations. High freshwater discharge due to snow and ice melt and the presence of the tidewater glaciers makes the bay extremely cold. There are many small- and large-scale mixing and upwelling zones at sills, glacial faces, and streams. The complex topography and strong currents lead to highly variable salinity, temperature, sediment, primary productivity, light penetration, stratification levels, and current patterns within a small area. The oceanographic patterns within Glacier Bay drive a large portion of the spatial and temporal variability of the ecosystem. It has been widely recognized by scientists and resource managers in Glacier Bay that a program to monitor oceanographic patterns is essential for understanding the marine ecosystem and to differentiate between anthropogenic disturbance and natural variation. This year’s sampling marks the 12th continuous year of monitoring the oceanographic conditions at 23 stations along the primary axes within Glacier Bay, AK, making this a very unique and valuable data set in terms of its spatial and temporal coverage.

Small-area snow surveys on the northern plains of North Dakota

USGS Publications Warehouse

Emerson, Douglas G.; Carroll, T.R.; Steppuhn, Harold

1985-01-01

Snow-cover data are needed for many facets of hydrology. The variation in snow cover over small areas is the focus of this study. The feasibility of using aerial surveys to obtain information on the snow water equivalent of the snow cover in order to minimize the necessity of labor intensive ground snow surveys was- evaluated. A low-flying aircraft was used to measure attenuations of natural terrestrial gamma radiation by snow cover. Aerial and ground snow surveys of eight 1-mile snow courses and one 4-mile snow course were used in the evaluation, with ground snow surveys used as the base to evaluate aerial data. Each of the 1-mile snow courses consisted of a single land use and all had the same terrain type (plane). The 4-mile snow course consists of a variety of land uses and the same terrain type (plane). Using the aerial snow-survey technique, the snow water equivalent of the 1-mile snow courses was. measured with three passes of the aircraft. Use of more than one pass did not improve the results. The mean absolute difference between the aerial- and ground-measured snow water equivalents for the 1-mile snow courses was 26 percent (0.77 inches). The aerial snow water equivalents determined for the 1-mile snow courses were used to estimate the variations in the snow water equivalents over the 4-mile snow course. The weighted mean absolute difference for the 4-mile snow course was 27 percent (0.8 inches). Variations in snow water equivalents could not be verified adequately by segmenting the aerial snow-survey data because of the uniformity found in the snow cover. On the 4-mile snow coirse, about two-thirds of the aerial snow-survey data agreed with the ground snow-survey data within the accuracy of the aerial technique ( + 0.5 inch of the mean snow water equivalent).

Geomorphic controls on floodplain organic carbon storage in sediment along five rivers in interior Alaska

NASA Astrophysics Data System (ADS)

Lininger, K.; Wohl, E.; Rose, J. R.

2016-12-01

High latitude permafrost regions contain large amounts of organic carbon (OC) in the subsurface, but little work has quantified OC storage in floodplain sediment in the high latitudes. Floodplains influence the export of OC to the ocean by temporarily storing OC at timescales of 101 to 103 years. To fully understand terrestrial carbon cycling, the storage and residence time of OC in floodplains, and the geomorphic controls on OC storage, must be taken into account. Small-scale spatial variations in OC storage within floodplains likely reflect geomorphic processes of deposition and floodplain development. We present results of floodplain OC storage and residence time in sediment along 5 rivers in the Yukon Flats National Wildlife Refuge in interior Alaska, a region with discontinuous permafrost. We collected sediment samples within the active layer along tributaries to the Yukon River and the mainstem Yukon River and analyzed the sediment samples for OC content. We classified sample locations by geomorphic type (filled secondary channels, levees, point bars) and vegetation type (herbaceous, deciduous/shrub, white spruce, and black spruce wetlands), and found that both geomorphology and vegetation influence OC concentration and OC mass per area. Preliminary results suggest that filled secondary channels contain more OC per area compared to other geomorphic types. We present results of radiocarbon dates from river cutbanks associated with our sampling sites, which give a maximum age for residence times of OC in sediment before erosion and transport. The radiocarbon dates also provide estimates of long-term OC accretion within the Yukon Flats floodplains. Small-scale variations within floodplains as a result of floodplain depositional processes and vegetation communities shed light on the geomorphic controls on OC storage. This work will help constrain the spatial variation in OC storage and OC residence time across the landscape in a region experiencing rapid climate change and permafrost thaw.

Estimating cigarette tax avoidance and evasion: evidence from a national sample of littered packs.

PubMed

Barker, Dianne C; Wang, Shu; Merriman, David; Crosby, Andrew; Resnick, Elissa A; Chaloupka, Frank J

2016-10-01

A number of recent studies document the proportion of all cigarette packs that are 'contraband' using discarded packs to measure tax avoidance and evasion, which we call tax non-compliance. To date, academic studies using discarded packs focused on relatively small geographical areas such as a city or a neighbourhood. We visited 160 communities across 38 US states in 2012 and collected data from littered cigarette packs as part of the State and Community Tobacco Control (SCTC) Research Initiative and the Bridging the Gap Community Obesity Measures Project (BTG-COMP). Data collectors were trained in a previously tested littered pack data collection protocol. Field teams collected 2116 packs with cellophane across 132 communities. We estimate a national tax non-compliance rate of 18.5% with considerable variation across regions. Suburban areas had lower non-compliance than urban areas as well as areas with high and low median household income areas compared with middle income areas. We present the first academic national study of tax non-compliance using littered cigarette packs. We demonstrate the feasibility of meaningful large-scale data collection using this methodology and document considerable variation in tax non-compliance across areas, suggesting that both policy differences and geography may be important in control of illicit tobacco use. Given the geography of open borders among countries with varying tax rates, this simple methodology may be appropriate to estimate tax non-compliance in countries that use tax stamps or other pack markings, such as health warnings. 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/.

Light-dependent leaf trait variation in 43 tropical dry forest tree species.

PubMed

Markesteijn, Lars; Poorter, Lourens; Bongers, Frans

2007-04-01

Our understanding of leaf acclimation in relation to irradiance of fully grown or juvenile trees is mainly based on research involving tropical wet forest species. We studied sun-shade plasticity of 24 leaf traits of 43 tree species in a Bolivian dry deciduous forest. Sampling was confined to small trees. For each species, leaves were taken from five of the most and five of the least illuminated crowns. Trees were selected based on the percentage of the hemisphere uncovered by other crowns. We examined leaf trait variation and the relation between trait plasticity and light demand, maximum adult stature, and ontogenetic changes in crown exposure of the species. Leaf trait variation was mainly related to differences among species and to a minor extent to differences in light availability. Traits related to the palisade layer, thickness of the outer cell wall, and N(area) and P(area) had the greatest plasticity, suggesting their importance for leaf function in different light environments. Short-lived pioneers had the highest trait plasticity. Overall plasticity was modest and rarely associated with juvenile light requirements, adult stature, or ontogenetic changes in crown exposure. Dry forest tree species had a lower light-related plasticity than wet forest species, probably because wet forests cast deeper shade. In dry forests light availability may be less limiting, and low water availability may constrain leaf trait plasticity in response to irradiance.

Pollinator-mediated selection on floral morphology: evidence for transgressive evolution in a derived hybrid lineage.

PubMed

Anton, K A; Ward, J R; Cruzan, M B

2013-03-01

Hybridization between closely related lineages is a mechanism that might promote substantive changes in phenotypic traits of descendants, resulting in transgressive evolution. Interbreeding between divergent but morphologically similar lineages can produce exceptional phenotypes, but the potential for transgressive variation to facilitate long-term trait changes in derived hybrid lineages has received little attention. We compare pollinator-mediated selection on transgressive floral traits in both early-generation and derived hybrid lineages of the Piriqueta cistoides ssp. caroliniana complex. The bowl-shaped flowers of morphotypes in this complex have similar gross morphologies and attract a common suite of small insect pollinators. However, they are defined by significant differences in characters that generate pollinator interest and visitation, including floral area and petal separation. In common garden experiments, patterns of pollen deposition in early-generation recombinant hybrids indicate that Piriqueta's pollinators favour flowers with greater area and reduced petal separation. Changes in floral morphology in derived hybrid lineages are consistent with predictions from selection gradients, but the magnitude of change is limited relative to the range of transgressive variation. These results suggest that hybridization provides variation for evolution of divergent floral traits. However, the potential for extreme transgressive variants to contribute to phenotypic shifts may be limited due to reduced heritability, evolutionary constraints or fitness trade-offs. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

Investigating microearthquake finite source attributes with IRIS Community Wavefield Demonstration Experiment in Oklahoma

NASA Astrophysics Data System (ADS)

Fan, Wenyuan; McGuire, Jeffrey J.

2018-05-01

An earthquake rupture process can be kinematically described by rupture velocity, duration and spatial extent. These key kinematic source parameters provide important constraints on earthquake physics and rupture dynamics. In particular, core questions in earthquake science can be addressed once these properties of small earthquakes are well resolved. However, these parameters of small earthquakes are poorly understood, often limited by available datasets and methodologies. The IRIS Community Wavefield Experiment in Oklahoma deployed ˜350 three component nodal stations within 40 km2 for a month, offering an unprecedented opportunity to test new methodologies for resolving small earthquake finite source properties in high resolution. In this study, we demonstrate the power of the nodal dataset to resolve the variations in the seismic wavefield over the focal sphere due to the finite source attributes of a M2 earthquake within the array. The dense coverage allows us to tightly constrain rupture area using the second moment method even for such a small earthquake. The M2 earthquake was a strike-slip event and unilaterally propagated towards the surface at 90 per cent local S- wave speed (2.93 km s-1). The earthquake lasted ˜0.019 s and ruptured Lc ˜70 m by Wc ˜45 m. With the resolved rupture area, the stress-drop of the earthquake is estimated as 7.3 MPa for Mw 2.3. We demonstrate that the maximum and minimum bounds on rupture area are within a factor of two, much lower than typical stress drop uncertainty, despite a suboptimal station distribution. The rupture properties suggest that there is little difference between the M2 Oklahoma earthquake and typical large earthquakes. The new three component nodal systems have great potential for improving the resolution of studies of earthquake source properties.

Computing Evaporation Using Meteorological Data for Hydrological Budget of Lake Wapalanne in NJ School of Conservation

NASA Astrophysics Data System (ADS)

Jordan, J. J.; Barrett, K. R.; Galster, J. C.; Ophori, D. U.; Flores, D.; Kelly, S. A.; Lutey, A. M.

2011-12-01

Lake Wapalanne is small manmade lake about 5.4 hectares in northwest New Jersey in the Highlands Physiographic province within permanently protected land. The lake's surrounding area consists of forested vegetation and is relatively unoccupied which minimizes human influence. The lake's small size, minimal external influence, geographic isolation, and protected status provide an optimal research environment to record meteorological data used in calculation of potential evaporation. Between July 7h and August 3rd meteorological data was collected from a professional weather station placed on an island directly in the center of Lake Wapalanne. The Vantage Pro2 weather station provided accurate readings of temperate, humidity, wind-speed and direction, precipitation, and atmospheric pressure. A bathometric survey of the lake was conducted to determine the surface area with variations in depth of the lake's water level. Using the collected weather station data, a rate of potential evaporation was determined with several evaporation equations. A quantified volume was then derived from the rate and surface area of the lake. Using small scale evaporation measurements of known volumes of water within small pans placed in the lake water and National Oceanic and Atmospheric Administration evaporation stations near the experiment site, a comparison and validation of the calculated potential evaporation accuracy and regional evaporation is achieved. This three year study is part of an ongoing NSF Research Experience for Undergraduates (REU) project that encompasses additional topics of lake research; see abstract from Kelly et al. AGU 2011 for more information on the lake's hydrologic budget. The results and methods of this study will be of use in future forecasting and baseline measurements of hydrologic budgets for lakes and reservoirs within regional proximity, which provide drinking water to over five million people in the State of New Jersey.

Spatial and temporal variation of correlation between the Arctic total ozone and atmospheric temperature

NASA Astrophysics Data System (ADS)

Huang, Fuxiang; Ren, suling; Han, Shuangshuang; Zheng, xiangdong; Deng, xuejiao

2017-04-01

Daily total ozone and atmospheric temperature profile data in 2015 from the AIRS are used to investigate the spatial and temporal variation of the correlation between the Arctic atmospheric ozone and temperature. In the study, 11 lays atmospheric temperature profiles from the troposphere to the stratosphere are investigated. These layer heights are 20, 50, 70, 100, 200, 250, 300, 400, 500, 600 and 700 hPa respectively. The results show that a significant seasonal split exists in the correlation between the Arctic ozone and atmospheric temperature. Figure 1 shows the spatial and temporal variation of the coefficient between the atmospheric ozone and temperature at 50hPa. It can be seen from the figure that an obvious spatiotemporal difference exists in the correlation between the Arctic total ozone and atmospheric temperature in the lower stratosphere. First, the seasonal difference is very remarkable, which is shown as a significant positive correlation in most regions during winter and summer, while no correlation in the majority of regions occurs during spring and autumn, with a weak positive or negative correlation in a small number regions. Second, the spatial differences are also very obvious. The summer maximum correlation coefficient occurs in the Barents Sea and other locations at 0.8 and above, while the winter maximum occurs in the Baffin Bay area at 0.6 to 0.8. However, in a small number of regions, such as the land to the west of the Bering Strait in winter and the Arctic Ocean core area in summer, the correlation coefficients were unable to pass the significance test to show no correlation. At the same time, in spring and autumn, a positive correlation only occurs over a few low-latitude land areas, while over other Arctic areas, weak negative correlation exists. The differences in horizontal position are clearly related to the land-sea distribution, underlying surface characteristics, glacial melting, and other factors. In the troposphere, the ozone and temperature have a strong negative correlation in spring and autumn, while presenting a weak negative correlation or no correlation in winter and summer. Figure 2 shows the spatial and temporal variation of the correlation coefficient between the atmospheric ozone and temperature at 500hPa. From figure 2, it can be seen that in the Arctic troposphere, the atmospheric ozone and tropospheric temperature mainly have a negative correlation. In winter and summer, a weak negative correlation is shown overall, but more than a third of the regions show no correlation. In spring, the negative correlation is the strongest between the ozone and temperature. Especially in Greenland - Queen Elizabeth Islands and southern New Siberian Islands, the correlation is the highest, with a correlation coefficient of -0.9 and above, followed by a negative correlation in autumn. Except for a small number of low-latitude scattered regions with weak correlation, the correlation coefficients of most regions are ranged between -0.5 and -0.7. At 300 hPa near the tropopause, the horizontal distribution and seasonal change of the correlation between the Arctic total ozone and atmospheric temperature are as shown in Fig. 3.At the height near the Arctic tropopause, the atmospheric ozone mainly has no correlation to temperature, especially in winter and summer, when no correlation exists in the majority of regions, while weak positive or negative correlation occurs in a small number of areas. In the majority of regions during spring, a weak negative correlation is shown, while no correlation appears in Western Greenland - Queen Elizabeth Islands. In autumn, most regions show no correlation, while weak negative correlation is presented in Eastern Greenland, Norwegian Sea - Barents Sea, and other locations. From figure 1-3, we can see a significant difference exists from the common law of positive correlation in the lower stratosphere and negative correlation in the troposphere at mid-low latitudes. The Arctic atmospheric ozone has a relation with temperature, showing significant spatial and temporal variation characteristics. In the stratosphere, winter and summer atmospheric temperatures mainly have a positive correlation to ozone. The summer maximum occurs in the Barents Sea to achieve 0.8 and above, while the winter maximum is 0.6 to 0.8 in the Baffin Bay area. In the troposphere, the autumn and spring atmospheric temperatures mainly have a negative correlation to the ozone. The spring correlation coefficient in Greenland to the Queen Elizabeth Islands reaches up to -0.9 and above, while the autumn value is -0.5 to -0.7. At about 300 hPa, the tropopause value is reduced to 0, and further decreased in the troposphere, to show a strong negative correlation. Based on the comprehensive analysis of various influence factors, the possible action mechanism of the spatiotemporal variation pattern of the correlation between the Arctic atmospheric ozone and temperature is discussed based on the seasonal differences of various influence factors. The spatial and temporal variation characteristics of the correlation between the Arctic atmospheric ozone and temperature are determined by the seasonal variation of various influencing factors of the Arctic atmospheric ozone and temperature. These factors include the atmospheric heating effect from the ozone matching with the Arctic sunshine conditions, the influence of dynamic delivery on the ozone and heat, the impact of underlying-surface glacial melting on atmospheric radiation and heat budget, and so on. At different heights in each season, the different effects from all kinds of factors on the ozone and temperature determine the spatiotemporal variation of the correlation between the ozone and temperature.

Responses of infaunal populations to benthoscape structure and the potential importance of transition zones

USGS Publications Warehouse

Zajac, R.N.; Lewis, R.S.; Poppe, L.J.; Twichell, D.C.; Vozarik, J.; DiGiacomo-Cohen, M. L.

2003-01-01

Relationships between population abundance and seafloor landscape, or benthoscape, structure were examined for 16 infaunal taxa in eastern Long Island Sound. Based on analyses of a side-scan sonar mosaic, the 19.4-km2 study area was comprised of six distinct large-scale (> km2) benthoscape elements, with varying levels of mesoscale (km2-m2) and small-scale (2) physical and biological habitat heterogeneity. Transition zones among elements varied from ~50 to 200 m in width, comprised ~32% of the benthoscape, and added to overall benthoscape heterogeneity. Population abundances of nine taxa varied significantly among the large-scale elements. Most species were found at high abundances only in one benthoscape element, but three had several foci of elevated abundances. Analyses of population responses to habitat heterogeneity at different spatial scales indicated that abundances of eight taxa varied significantly among spatial scales, but the significant scales were mixed among these species. Relatively large residual variations suggest significant amounts of mesoscale spatial variation were unaccounted for, varying from ~1 km2 to several m2. Responses to transition zones were mixed as well. Abundances of nine taxa varied significantly among transition zones and interiors of benthoscape elements, most with elevated abundances in transition zones. Our results show that infaunal populations exhibit complex and spatially varying patterns of abundance in relation to benthoscape structure and suggest that mesoscale variation may be particularly critical in this regard. Also, transition zones among benthoscape features add considerably to this variation and may be ecological important areas in seafloor environments.

Movement is the glue connecting home ranges and habitat selection.

PubMed

Van Moorter, Bram; Rolandsen, Christer M; Basille, Mathieu; Gaillard, Jean-Michel

2016-01-01

Animal space use has been studied by focusing either on geographic (e.g. home ranges, species' distribution) or on environmental (e.g. habitat use and selection) space. However, all patterns of space use emerge from individual movements, which are the primary means by which animals change their environment. Individuals increase their use of a given area by adjusting two key movement components: the duration of their visit and/or the frequency of revisits. Thus, in spatially heterogeneous environments, animals exploit known, high-quality resource areas by increasing their residence time (RT) in and/or decreasing their time to return (TtoR) to these areas. We expected that spatial variation in these two movement properties should lead to observed patterns of space use in both geographic and environmental spaces. We derived a set of nine predictions linking spatial distribution of movement properties to emerging space-use patterns. We predicted that, at a given scale, high variation in RT and TtoR among habitats leads to strong habitat selection and that long RT and short TtoR result in a small home range size. We tested these predictions using moose (Alces alces) GPS tracking data. We first modelled the relationship between landscape characteristics and movement properties. Then, we investigated how the spatial distribution of predicted movement properties (i.e. spatial autocorrelation, mean, and variance of RT and TtoR) influences home range size and hierarchical habitat selection. In landscapes with high spatial autocorrelation of RT and TtoR, a high variation in both RT and TtoR occurred in home ranges. As expected, home range location was highly selective in such landscapes (i.e. second-order habitat selection); RT was higher and TtoR lower within the selected home range than outside, and moose home ranges were small. Within home ranges, a higher variation in both RT and TtoR was associated with higher selectivity among habitat types (i.e. third-order habitat selection). Our findings show how patterns of geographic and environmental space use correspond to the two sides of a coin, linked by movement responses of individuals to environmental heterogeneity. By demonstrating the potential to assess the consequences of altering RT or TtoR (e.g. through human disturbance or climatic changes) on home range size and habitat selection, our work sets the basis for new theoretical and methodological advances in movement ecology. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

Commuting to work: RN travel time to employment in rural and urban areas.

PubMed

Rosenberg, Marie-Claire; Corcoran, Sean P; Kovner, Christine; Brewer, Carol

2011-02-01

To investigate the variation in average daily travel time to work among registered nurses (RNs) living in urban, suburban, and rural areas. We examine how travel time varies across RN characteristics, job setting, and availability of local employment opportunities. Descriptive statistics and linear regression using a 5% sample from the 2000 Census and a longitudinal survey of newly licensed RNs (NLRN). Travel time for NLRN respondents was estimated using geographic information systems (GIS) software. In the NLRN, rural nurses and those living in small towns had significantly longer average commute times. Young married RNs and RNs with children also tended to have longer commute times, as did RNs employed by hospitals. The findings indicate that travel time to work varies significantly across locale types. Further research is needed to understand whether and to what extent lengthy commute times impact RN workforce needs in rural and urban areas.

Inference of financial networks using the normalised mutual information rate.

PubMed

Goh, Yong Kheng; Hasim, Haslifah M; Antonopoulos, Chris G

2018-01-01

In this paper, we study data from financial markets, using the normalised Mutual Information Rate. We show how to use it to infer the underlying network structure of interrelations in the foreign currency exchange rates and stock indices of 15 currency areas. We first present the mathematical method and discuss its computational aspects, and apply it to artificial data from chaotic dynamics and to correlated normal-variates data. We then apply the method to infer the structure of the financial system from the time-series of currency exchange rates and stock indices. In particular, we study and reveal the interrelations among the various foreign currency exchange rates and stock indices in two separate networks, of which we also study their structural properties. Our results show that both inferred networks are small-world networks, sharing similar properties and having differences in terms of assortativity. Importantly, our work shows that global economies tend to connect with other economies world-wide, rather than creating small groups of local economies. Finally, the consistent interrelations depicted among the 15 currency areas are further supported by a discussion from the viewpoint of economics.

Inference of financial networks using the normalised mutual information rate

PubMed Central

2018-01-01

In this paper, we study data from financial markets, using the normalised Mutual Information Rate. We show how to use it to infer the underlying network structure of interrelations in the foreign currency exchange rates and stock indices of 15 currency areas. We first present the mathematical method and discuss its computational aspects, and apply it to artificial data from chaotic dynamics and to correlated normal-variates data. We then apply the method to infer the structure of the financial system from the time-series of currency exchange rates and stock indices. In particular, we study and reveal the interrelations among the various foreign currency exchange rates and stock indices in two separate networks, of which we also study their structural properties. Our results show that both inferred networks are small-world networks, sharing similar properties and having differences in terms of assortativity. Importantly, our work shows that global economies tend to connect with other economies world-wide, rather than creating small groups of local economies. Finally, the consistent interrelations depicted among the 15 currency areas are further supported by a discussion from the viewpoint of economics. PMID:29420644

Does Walkability Contribute to Geographic Variation in Psychosocial Distress? A Spatial Analysis of 91,142 Members of the 45 and Up Study in Sydney, Australia

PubMed Central

Morgan, Geoffrey G.; Jalaludin, Bin B.; Bauman, Adrian E.

2018-01-01

Walkability describes the capacity of the built environment to promote walking, and has been proposed as a potential focus for community-level mental health planning. We evaluated this possibility by examining the contribution of area-level walkability to variation in psychosocial distress in a population cohort at spatial scales comparable to those used for regional planning in Sydney, Australia. Data on psychosocial distress were analysed for 91,142 respondents to the 45 and Up Study baseline survey between January 2006 and April 2009. We fit conditional auto regression models at the postal area level to obtain smoothed “disease maps” for psychosocial distress, and assess its association with area-level walkability after adjusting for individual- and area-level factors. Prevalence of psychosocial distress was 7.8%; similar for low (7.9%), low-medium (7.9%), medium-high (8.0%), and high (7.4%) walkability areas; and decreased with reducing postal area socioeconomic disadvantage: 12.2% (most), 9.3%, 7.5%, 5.9%, and 4.7% (least). Unadjusted disease maps indicated strong geographic clustering of psychosocial distress with 99.0% of excess prevalence due to unobserved and spatially structured factors, which was reduced to 55.3% in fully adjusted maps. Spatial and unstructured variance decreased by 97.3% and 39.8% after adjusting for individual-level factors, and another 2.3% and 4.2% with the inclusions of area-level factors. Excess prevalence of psychosocial distress in postal areas was attenuated in adjusted models but remained spatially structured. Postal area prevalence of high psychosocial distress is geographically clustered in Sydney, but is unrelated to postal area walkability. Area-level socioeconomic disadvantage makes a small contribution to this spatial structure; however, community-level mental health planning will likely deliver greatest benefits by focusing on individual-level contributors to disease burden and inequality associated with psychosocial distress. PMID:29415461

Does Walkability Contribute to Geographic Variation in Psychosocial Distress? A Spatial Analysis of 91,142 Members of the 45 and Up Study in Sydney, Australia.

PubMed

Mayne, Darren J; Morgan, Geoffrey G; Jalaludin, Bin B; Bauman, Adrian E

2018-02-06

Walkability describes the capacity of the built environment to promote walking, and has been proposed as a potential focus for community-level mental health planning. We evaluated this possibility by examining the contribution of area-level walkability to variation in psychosocial distress in a population cohort at spatial scales comparable to those used for regional planning in Sydney, Australia. Data on psychosocial distress were analysed for 91,142 respondents to the 45 and Up Study baseline survey between January 2006 and April 2009. We fit conditional auto regression models at the postal area level to obtain smoothed "disease maps" for psychosocial distress, and assess its association with area-level walkability after adjusting for individual- and area-level factors. Prevalence of psychosocial distress was 7.8%; similar for low (7.9%), low-medium (7.9%), medium-high (8.0%), and high (7.4%) walkability areas; and decreased with reducing postal area socioeconomic disadvantage: 12.2% (most), 9.3%, 7.5%, 5.9%, and 4.7% (least). Unadjusted disease maps indicated strong geographic clustering of psychosocial distress with 99.0% of excess prevalence due to unobserved and spatially structured factors, which was reduced to 55.3% in fully adjusted maps. Spatial and unstructured variance decreased by 97.3% and 39.8% after adjusting for individual-level factors, and another 2.3% and 4.2% with the inclusions of area-level factors. Excess prevalence of psychosocial distress in postal areas was attenuated in adjusted models but remained spatially structured. Postal area prevalence of high psychosocial distress is geographically clustered in Sydney, but is unrelated to postal area walkability. Area-level socioeconomic disadvantage makes a small contribution to this spatial structure; however, community-level mental health planning will likely deliver greatest benefits by focusing on individual-level contributors to disease burden and inequality associated with psychosocial distress.

Mixing and Transport of Dust in the Early Solar Nebula as Inferred from Titanium Isotope Variations among Chondrules

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

Gerber, Simone; Burkhardt, Christoph; Budde, Gerrit

2017-05-20

Chondrules formed by the melting of dust aggregates in the solar protoplanetary disk and as such provide unique insights into how solid material was transported and mixed within the disk. Here, we show that chondrules from enstatite and ordinary chondrites show only small {sup 50}Ti variations and scatter closely around the {sup 50}Ti composition of their host chondrites. By contrast, chondrules from carbonaceous chondrites have highly variable {sup 50}Ti compositions, which, relative to the terrestrial standard, range from the small {sup 50}Ti deficits measured for enstatite and ordinary chondrite chondrules to the large {sup 50}Ti excesses known from Ca–Al-rich inclusionsmore » (CAIs). These {sup 50}Ti variations can be attributed to the addition of isotopically heterogeneous CAI-like material to enstatite and ordinary chondrite-like chondrule precursors. The new Ti isotopic data demonstrate that isotopic variations among carbonaceous chondrite chondrules do not require formation over a wide range of orbital distances, but can instead be fully accounted for by the incorporation of isotopically anomalous “nuggets” into chondrule precursors. As such, these data obviate the need for disk-wide transport of chondrules prior to chondrite parent body accretion and are consistent with formation of chondrules from a given chondrite group in localized regions of the disk. Finally, the ubiquitous presence of {sup 50}Ti-enriched material in carbonaceous chondrites and the lack of this material in the non-carbonaceous chondrites support the idea that these two meteorite groups derive from areas of the disk that remained isolated from each other, probably through the formation of Jupiter.« less

Water quality of Lake Austin and Town Lake, Austin, Texas

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

Andrews, F.L.; Wells, F.C.; Shelby, W.J.

1988-01-01

Lake Austin and Town Lake are impoundments on the Colorado River in Travis County, central Texas, and are a source of water for municipal industrial water supplies, electrical-power generation, and recreation for more than 500,000 people in the Austin metropolitan area. Small vertical temperature variations in both lakes were attributed to shallow depths in the lakes and short retention times of water in the lakes during the summer months. The largest areal variations in dissolved oxygen generally occur in Lake Austin during the summer as a result of releases of water from below the thermocline in Lake Travis. Except formore » iron, manganese, and mercury, dissolved concentrations of trace elements in water collected from Lake Austin and Town Lake did not exceed the primary or secondary drinking water standards set by the US Environmental Protection Agency. Little or no effect of stormwater runoff on temperature, dissolved oxygen, or minor elements could be detected in either Lake Austin or Town Lake. Little seasonal or areal variation was noted in nitrogen concentrations in Lake Austin or Town lake. Total phosphorus concentrations generally were small in both lakes. Increased concentrations of nitrogen and phosphorus were detected after storm runoff inflow in Town Lake, but not in Lake Austin; densities of fecal-coliform bacteria increased in Lake Austin and Town Lake, but were substantially greater in Town Lake than in Lake Austin. 18 refs., 38 figs., 59 tabs.« less

Tunable two-dimensional acoustic meta-structure composed of funnel-shaped unit cells with multi-band negative acoustic property

NASA Astrophysics Data System (ADS)

Cho, Sungjin; Kim, Boseung; Min, Dongki; Park, Junhong

2015-10-01

This paper presents a two-dimensional heat-exhaust and sound-proof acoustic meta-structure exhibiting tunable multi-band negative effective mass density. The meta-structure was composed of periodic funnel-shaped units in a square lattice. Each unit cell operates simultaneously as a Helmholtz resonator (HR) and an extended pipe chamber resonator (EPCR), leading to a negative effective mass density creating bandgaps for incident sound energy dissipation without transmission. This structure allowed large heat-flow through the cross-sectional area of the extended pipe since the resonance was generated by acoustic elements without using solid membranes. The pipes were horizontally directed to a flow source to enable small flow resistance for cooling. Measurements of the sound transmission were performed using a two-load, four-microphone method for a unit cell and small reverberation chamber for two-dimensional panel to characterize the acoustic performance. The effective mass density showed significant frequency dependent variation exhibiting negative values at the specific bandgaps, while the effective bulk modulus was not affected by the resonator. Theoretical models incorporating local resonances in the multiple resonator units were proposed to analyze the noise reduction mechanism. The acoustic meta-structure parameters to create broader frequency bandgaps were investigated using the theoretical model. The negative effective mass density was calculated to investigate the creation of the bandgaps. The effects of design parameters such as length, cross-sectional area, and volume of the HR; length and cross-sectional area of the EPCR were analyzed. To maximize the frequency band gap, the suggested acoustic meta-structure panel, small neck length, and cross-sectional area of the HR, large EPCR length was advantageous. The bandgaps became broader when the two resonant frequencies were similar.

Quantifying the influence of sediment source area sampling on detrital thermochronometer data

NASA Astrophysics Data System (ADS)

Whipp, D. M., Jr.; Ehlers, T. A.; Coutand, I.; Bookhagen, B.

2014-12-01

Detrital thermochronology offers a unique advantage over traditional bedrock thermochronology because of its sensitivity to sediment production and transportation to sample sites. In mountainous regions, modern fluvial sediment is often collected and dated to determine the past (105 to >107 year) exhumation history of the upstream drainage area. Though potentially powerful, the interpretation of detrital thermochronometer data derived from modern fluvial sediment is challenging because of spatial and temporal variations in sediment production and transport, and target mineral concentrations. Thermochronometer age prediction models provide a quantitative basis for data interpretation, but it can be difficult to separate variations in catchment bedrock ages from the effects of variable basin denudation and sediment transport. We present two examples of quantitative data interpretation using detrital thermochronometer data from the Himalaya, focusing on the influence of spatial and temporal variations in basin denudation on predicted age distributions. We combine age predictions from the 3D thermokinematic numerical model Pecube with simple models for sediment sampling in the upstream drainage basin area to assess the influence of variations in sediment production by different geomorphic processes or scaled by topographic metrics. We first consider a small catchment from the central Himalaya where bedrock landsliding appears to have affected the observed muscovite 40Ar/39Ar age distributions. Using a simple model of random landsliding with a power-law landslide frequency-area relationship we find that the sediment residence time in the catchment has a major influence on predicted age distributions. In the second case, we compare observed detrital apatite fission-track age distributions from 16 catchments in the Bhutan Himalaya to ages predicted using Pecube and scaled by various topographic metrics. Preliminary results suggest that predicted age distributions scaled by the rock uplift rate in Pecube are statistically equivalent to the observed age distributions for ~75% of the catchments, but may improve when scaled by local relief or specific stream power weighted by satellite-derived precipitation. Ongoing work is exploring the effect of scaling by other topographic metrics.

A father effect explains sex-ratio bias.

PubMed

Malo, Aurelio F; Martinez-Pastor, Felipe; Garcia-Gonzalez, Francisco; Garde, Julián; Ballou, Jonathan D; Lacy, Robert C

2017-08-30

Sex ratio allocation has important fitness consequences, and theory predicts that parents should adjust offspring sex ratio in cases where the fitness returns of producing male and female offspring vary. The ability of fathers to bias offspring sex ratios has traditionally been dismissed given the expectation of an equal proportion of X- and Y-chromosome-bearing sperm (CBS) in ejaculates due to segregation of sex chromosomes at meiosis. This expectation has been recently refuted. Here we used Peromyscus leucopus to demonstrate that sex ratio is explained by an exclusive effect of the father, and suggest a likely mechanism by which male-driven sex-ratio bias is attained. We identified a male sperm morphological marker that is associated with the mechanism leading to sex ratio bias; differences among males in the sperm nucleus area (a proxy for the sex chromosome that the sperm contains) explain 22% variation in litter sex ratio. We further show the role played by the sperm nucleus area as a mediator in the relationship between individual genetic variation and sex-ratio bias. Fathers with high levels of genetic variation had ejaculates with a higher proportion of sperm with small nuclei area. This, in turn, led to siring a higher proportion of sons (25% increase in sons per 0.1 decrease in the inbreeding coefficient). Our results reveal a plausible mechanism underlying unexplored male-driven sex-ratio biases. We also discuss why this pattern of paternal bias can be adaptive. This research puts to rest the idea that father contribution to sex ratio variation should be disregarded in vertebrates, and will stimulate research on evolutionary constraints to sex ratios-for example, whether fathers and mothers have divergent, coinciding, or neutral sex allocation interests. Finally, these results offer a potential explanation for those intriguing cases in which there are sex ratio biases, such as in humans. © 2017 The Author(s).

Population size is weakly related to quantitative genetic variation and trait differentiation in a stream fish.

PubMed

Wood, Jacquelyn L A; Tezel, Defne; Joyal, Destin; Fraser, Dylan J

2015-09-01

How population size influences quantitative genetic variation and differentiation among natural, fragmented populations remains unresolved. Small, isolated populations might occupy poor quality habitats and lose genetic variation more rapidly due to genetic drift than large populations. Genetic drift might furthermore overcome selection as population size decreases. Collectively, this might result in directional changes in additive genetic variation (VA ) and trait differentiation (QST ) from small to large population size. Alternatively, small populations might exhibit larger variation in VA and QST if habitat fragmentation increases variability in habitat types. We explored these alternatives by investigating VA and QST using nine fragmented populations of brook trout varying 50-fold in census size N (179-8416) and 10-fold in effective number of breeders, Nb (18-135). Across 15 traits, no evidence was found for consistent differences in VA and QST with population size and almost no evidence for increased variability of VA or QST estimates at small population size. This suggests that (i) small populations of some species may retain adaptive potential according to commonly adopted quantitative genetic measures and (ii) populations of varying sizes experience a variety of environmental conditions in nature, however extremely large studies are likely required before any firm conclusions can be made. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Diagnosing and Correcting Mass Accuracy and Signal Intensity Error Due to Initial Ion Position Variations in a MALDI TOFMS

NASA Astrophysics Data System (ADS)

Malys, Brian J.; Piotrowski, Michelle L.; Owens, Kevin G.

2018-02-01

Frustrated by worse than expected error for both peak area and time-of-flight (TOF) in matrix assisted laser desorption ionization (MALDI) experiments using samples prepared by electrospray deposition, it was finally determined that there was a correlation between sample location on the target plate and the measured TOF/peak area. Variations in both TOF and peak area were found to be due to small differences in the initial position of ions formed in the source region of the TOF mass spectrometer. These differences arise largely from misalignment of the instrument sample stage, with a smaller contribution arising from the non-ideal shape of the target plates used. By physically measuring the target plates used and comparing TOF data collected from three different instruments, an estimate of the magnitude and direction of the sample stage misalignment was determined for each of the instruments. A correction method was developed to correct the TOFs and peak areas obtained for a given combination of target plate and instrument. Two correction factors are determined, one by initially collecting spectra from each sample position used and another by using spectra from a single position for each set of samples on a target plate. For TOF and mass values, use of the correction factor reduced the error by a factor of 4, with the relative standard deviation (RSD) of the corrected masses being reduced to 12-24 ppm. For the peak areas, the RSD was reduced from 28% to 16% for samples deposited twice onto two target plates over two days.

Diagnosing and Correcting Mass Accuracy and Signal Intensity Error Due to Initial Ion Position Variations in a MALDI TOFMS

NASA Astrophysics Data System (ADS)

Malys, Brian J.; Piotrowski, Michelle L.; Owens, Kevin G.

2017-12-01

Frustrated by worse than expected error for both peak area and time-of-flight (TOF) in matrix assisted laser desorption ionization (MALDI) experiments using samples prepared by electrospray deposition, it was finally determined that there was a correlation between sample location on the target plate and the measured TOF/peak area. Variations in both TOF and peak area were found to be due to small differences in the initial position of ions formed in the source region of the TOF mass spectrometer. These differences arise largely from misalignment of the instrument sample stage, with a smaller contribution arising from the non-ideal shape of the target plates used. By physically measuring the target plates used and comparing TOF data collected from three different instruments, an estimate of the magnitude and direction of the sample stage misalignment was determined for each of the instruments. A correction method was developed to correct the TOFs and peak areas obtained for a given combination of target plate and instrument. Two correction factors are determined, one by initially collecting spectra from each sample position used and another by using spectra from a single position for each set of samples on a target plate. For TOF and mass values, use of the correction factor reduced the error by a factor of 4, with the relative standard deviation (RSD) of the corrected masses being reduced to 12-24 ppm. For the peak areas, the RSD was reduced from 28% to 16% for samples deposited twice onto two target plates over two days. [Figure not available: see fulltext.

Quantifying Biomass and Bare Earth Changes from the Hayman Fire Using Multi-temporal Lidar

NASA Astrophysics Data System (ADS)

Stoker, J. M.; Kaufmann, M. R.; Greenlee, S. K.

2007-12-01

Small-footprint multiple-return lidar data collected in the Cheesman Lake property prior to the 2002 Hayman fire in Colorado provided an excellent opportunity to evaluate Lidar as a tool to predict and analyze fire effects on both soil erosion and overstory structure. Re-measuring this area and applying change detection techniques allowed for analyses at a high level of detail. Our primary objectives focused on the use of change detection techniques using multi-temporal lidar data to: (1) evaluate the effectiveness of change detection to identify and quantify areas of erosion or deposition caused by post-fire rain events and rehab activities; (2) identify and quantify areas of biomass loss or forest structure change due to the Hayman fire; and (3) examine effects of pre-fire fuels and vegetation structure derived from lidar data on patterns of burn severity. While we were successful in identifying areas where changes occurred, the original error bounds on the variation in actual elevations made it difficult, if not misleading to quantify volumes of material changed on a per pixel basis. In order to minimize these variations in the two datasets, we investigated several correction and co-registration methodologies. The lessons learned from this project highlight the need for a high level of flight planning and understanding of errors in a lidar dataset in order to correctly estimate and report quantities of vertical change. Directly measuring vertical change using only lidar without ancillary information can provide errors that could make quantifications confusing, especially in areas with steep slopes.

Trophic niche overlap of sprat and commercial small pelagic teleosts in the Gulf of Lions (NW Mediterranean Sea)

NASA Astrophysics Data System (ADS)

Le Bourg, B.; Bănaru, D.; Saraux, C.; Nowaczyk, A.; Le Luherne, E.; Jadaud, A.; Bigot, J. L.; Richard, P.

2015-09-01

Increasing abundance of non-commercial sprats and decreasing biomass and landings of commercial anchovies and sardines justify the need to study the feeding ecology and trophic niche overlap of these planktivorous species in the Gulf of Lions. Their diet has been investigated on the basis of stomach content and stable isotope analyses in 2011 and 2012 according to different depths and regions in the study area. The main prey were Corycaeidae copepods, Clauso/Paracalanus, Euterpina acutifrons and Microsetella, for sprats and small copepods, such as Microsetella, Oncaea and Corycaeidae, for anchovies and sardines. This is the first time that the diet of sprats is described in the Gulf of Lions. Sprats fed on a larger size spectrum of prey and seem to be more generalist feeders compared to anchovies and sardines. Ontogenetic changes as well as spatial and temporal variations of the diet occurred in the three species. Stable isotope analysis revealed mobility of sardines and sprats among feeding areas while anchovies exhibited preferred feeding areas. Sprats showed a higher relative condition assessed by C/N ratios than sardines and anchovies. Our results showed an overlap of the trophic niches for the three species, indicating a potential trophic competition in the Gulf of Lions.

Gas hydrate and spatial venting variations in the continental margin offshore Southwestern Taiwan

NASA Astrophysics Data System (ADS)

Lin, S.; Lim, Y.; Hsieh, W.; Yang, T.; Wang, Y.

2006-12-01

Strong BSR, high methane contents and rapid sulfate reduction were found in the continental margin sediments offshore southwestern Taiwan. In order to identify the venting phenomena and its relationship with gas hydrate, this research investigate sea floor vent features using WHOI?|s Towcam system as well as piston core in the study region. A total of 10 dives were conducted on board the r/v OR-1. Pore water sulfate, dissolved sulfide, methane, chloride, del O18 ratio, sediment organic carbon, carbonate content and carbonate del C13 ratio, pyrite-S were measured Large spatial variations were found based on pictures obtained from Towcam system and piston cores. Active venting features include bacteria mat, live dense bivalve patches, gas plume, temperature and salinity fluctuations, rapid sulfate reduction and high concentrations of methane in sediments. In addition, vent chimney, pockmark and large authigenic carbonate buildup were also observed in the active venting area. In contrast, in some areas without active venting features, scatter dead chimney, semi- buried carbonate structures, and dead bivalves were found. Total sulfate depletion was found at depth as shallow as 1 meter below sediment water interface in area near active vent whereas almost no sulfate depletion was observed in areas without any vent feature. Stages of carbonate build up existed, with initial phase dominated by small tube, chimney, and later with massive carbonate structures protruding the sea floor. The appearances of massive carbonate buildup structures seemed to indicate the end stage of gas hydrate venting phenomena.

General Practice Clinical Data Help Identify Dementia Hotspots: A Novel Geospatial Analysis Approach.

PubMed

Bagheri, Nasser; Wangdi, Kinley; Cherbuin, Nicolas; Anstey, Kaarin J

2018-01-01

We have a poor understanding of whether dementia clusters geographically, how this occurs, and how dementia may relate to socio-demographic factors. To shed light on these important questions, this study aimed to compute a dementia risk score for individuals to assess spatial variation of dementia risk, identify significant clusters (hotspots), and explore their association with socioeconomic status. We used clinical records from 16 general practices (468 Statistical Area level 1 s, N = 14,746) from the city of west Adelaide, Australia for the duration of 1 January 2012 to 31 December 2014. Dementia risk was estimated using The Australian National University-Alzheimer's Disease Risk Index. Hotspot analyses were applied to examine potential clusters in dementia risk at small area level. Significant hotspots were observed in eastern and southern areas while coldspots were observed in the western area within the study perimeter. Additionally, significant hotspots were observed in low socio-economic communities. We found dementia risk scores increased with age, sex (female), high cholesterol, no physical activity, living alone (widow, divorced, separated, or never married), and co-morbidities such as diabetes and depression. Similarly, smoking was associated with a lower dementia risk score. The identification of dementia risk clusters may provide insight into possible geographical variations in risk factors for dementia and quantify these risks at the community level. As such, this research may enable policy makers to tailor early prevention strategies to the correct individuals within their precise locations.

Annual and seasonal variability of metals and metalloids in urban and industrial soils in Alcalá de Henares (Spain).

PubMed

Peña-Fernández, A; Lobo-Bedmar, M C; González-Muñoz, M J

2015-01-01

Contamination of urban and industrial soils with trace metals has been recognized as a major concern at local, regional and global levels due to their implication on human health. In this study, concentrations of aluminum (Al), arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), tin (Sn), thallium (Tl), vanadium (V) and zinc (Zn) were determined in soil samples collected in Alcalá de Henares (Madrid, Spain) in order to evaluate the annual and seasonal variation in their levels. The results show that the soils of the industrial area have higher metals concentrations than the urban area. Principal component analysis (PCA) revealed that the two principal sources of trace metal contamination, especially Cd, Cu, Pb, and Zn in the urban soils of Alcalá can be attributed to traffic emissions, while As, Ni and Be primarily originated from industrial discharges. The seasonal variation analysis has revealed that the emission sources in the industrial area remain constant with time. However, in urban areas, both emissions and emission pathways significantly increase over time due to ongoing development. Currently, there is no hypothesis that explains the small seasonal fluctuations of trace metals in soils, since there are many factors affecting this. Owing to the fact that urban environments are becoming the human habitat, it would therefore be advisable to monitor metals and metalloids in urban soils because of the potential risks to human health. Copyright © 2014 Elsevier Inc. All rights reserved.

How might the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 affect the financial viability of rural pharmacies? An analysis of preimplementation prescription volume and payment sources in rural and urban areas.

PubMed

Fraher, Erin P; Slifkin, Rebecca T; Smith, Laura; Randolph, Randy; Rudolf, Matthew; Holmes, George M

2005-01-01

Passage of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA) has created interest in how the legislation will affect access to prescription drugs among rural beneficiaries. Policy attention has focused to a much lesser degree on the implications of the MMA for the financial viability of rural pharmacies. This article presents descriptive information on mail-order prescriptions, volume, and payer type of retail prescriptions in rural vs urban areas. Together, these data provide a baseline for evaluating how implementation of the MMA may affect the financial viability of rural independent pharmacies. Projections of prescriptions dispensed from retail and mail-order pharmacies in 2002 for the total US and a sample of 17 states were obtained from IMS Health. The volume of mail-order prescriptions is small. Rural providers prescribed fewer retail and mail-order prescriptions per person, but more units per person. Rural areas have a higher percentage of prescriptions paid for by cash (18% vs 13%) and Medicaid (16% vs 10%) and a lower percentage of third-party payers than urban areas. Significant variation in volume and payer type exists between states. Rural, independent pharmacies may be negatively affected by MMA implementation as business shifts from cash to third-party reimbursement. The high degree of variation between states also has potentially important implications for the implementation of Prescription Drug Plan regions under MMA.

Small sensitivity to temperature variations of Si-photonic Mach-Zehnder interferometer using Si and SiN waveguides

NASA Astrophysics Data System (ADS)

Hiraki, Tatsurou; Fukuda, Hiroshi; Yamada, Koji; Yamamoto, Tsuyoshi

2015-03-01

We demonstrated a small sensitivity to temperature variations of delay-line Mach-Zehnder interferometer (DL MZI) on a Si photonics platform. The key technique is to balance a thermo-optic effect in the two arms by using waveguide made of different materials. With silicon and silicon nitride waveguides, the fabricated DL MZI with a free-spectrum range of ~40 GHz showed a wavelength shift of -2.8 pm/K with temperature variations, which is 24 times smaller than that of the conventional Si-waveguide DL MZI. We also demonstrated the decoding of the 40-Gbit/s differential phase-shift keying signals to on-off keying signals with various temperatures. The tolerable temperature variation for the acceptable power penalty was significantly improved due to the small wavelength shifts.

Lake Level Variation in Small Lakes: Not a Clear Picture

NASA Astrophysics Data System (ADS)

Starratt, S.

2017-12-01

Lake level is a useful tool for identifying regional changes in precipitation and evaporation. Due to the volume of water in large lakes, they may only record large-scale changes in water balance, while smaller lakes may record more subtle variations. However, the record of water level in small lakes is affected by a number of factors including elevation, bathymetry, nutrient load, and aquatic macrophyte abundance. The latest Quaternary diatom records from three small lakes with areas of <10 ha (Hobart Lake, OR, 1458 masl; Swamp Lake, CA, 1554 masl; Favre Lake, NV, 2899 masl) and a larger lake (Medicine Lake, CA, 2036 masl, 154 ha) were compared in this study. All the lakes have a deep central basin (>10 m) surrounded by a shallow (1-2 m) shelf. Changes in the abundance of diatoms representing different life habits (benthic, tychoplanktic, planktic) were used to identify lake level variation. Benthic taxa dominate the assemblage when only the central basin is occupied. As the shallow shelf is flooded, the abundance of tychoplanktic taxa increases. Planktic taxa increase with the establishment of stratification. Favre Lake presents the clearest indication of initial lake level rise (7600-5750 cal yr BP) and intermittent flooding of the shelf for the remainder of the record. Stratification appears to become established only in the last few hundred years. Higher nutrient levels in the early part of the Hobart Lake record lead to a nearly monotypic planktic assemblage which is replaced by a tychoplanktic-dominated assemblage as the lake floods the shelf at about 3500 cal yr BP. The last 500 years is dominated by benthic taxa associated with aquatic macrophytes. The consistent presence of planktic taxa in the Swamp Lake record suggests that the lake was stratified during most of its history, although slight variations in the relative abundances of planktic and tychoplanktic groups occur. The Medicine Lake record shows a gradual increase in planktic species between 11,400 and 5500 cal yr BP, reflecting a gradual increase in stratification. Changes in the abundance of benthic and planktic taxa during the remainder of the record indicate variations in the shallow (<2 m) part of the lake. These results indicate diatom ecological groups show promise as a proxy for lake level reconstructions, and further ground-truthing is necessary.

Primer Vector Optimization: Survey of Theory, New Analysis and Applications

NASA Technical Reports Server (NTRS)

Guzman, J. J.; Mailhe, L. M.; Schiff, C.; Hughes, S. P.; Folta, D. C.

2002-01-01

In this paper, a summary of primer vector theory is presented. The applicability of primer vector theory is examined in an effort to understand when and why the theory can fail. For example, since the Calculus of Variations is based on "small" variations, singularities in the linearized (variational) equations of motion along the arcs must be taken into account. These singularities are a recurring problem in analyse that employ small variations. Two examples, the initialization of an orbit and a line of apsides rotation, are presented. Recommendations, future work, and the possible addition of other optimization techniques are also discussed.

Small-scale variability of zooplankton pyruvate kinase activity in the Gironde Estuary plume (Atlantic French Coast): A case study under unusually low freshwater discharge

NASA Astrophysics Data System (ADS)

Bergeron, Jean-Pierre

2006-09-01

Pyruvate kinase (PK) activity measurements are used to assess the role of carbohydrates in global feeding of mesozooplankton communities inhabiting an estuary plume. As a consequence of a remarkably low freshwater discharge rate, the sea surface layers of the area under estuarine influence showed a very moderate salinity fall and a nearly total depletion in nitrates, whereas higher levels of these nutrients were found in deeper, more saline, layers. Small-scale PK activity variations in mesozooplankton appear to be closely correlated to nitrate integration values within the water column. The results were analysed in comparison with literature reports. The study produced a coherent overall interpretation, which strongly supports the reliability of this new biochemical tool in detecting assimilation of trace carbohydrates in the diet of mesozooplankton.

General practitioners in German metropolitan areas - distribution patterns and their relationship with area level measures of the socioeconomic status.

PubMed

Bauer, Jan; Brueggmann, Doerthe; Ohlendorf, Daniela; Groneberg, David A

2016-11-25

Geographical variation of the general practitioner (GP) workforce is known between rural and urban areas. However, data about the variation between and within urban areas are lacking. We analyzed distribution patterns of GP full time equivalents (FTE) in German cities with a population size of more than 500,000. We correlated their distribution with area measures of social deprivation in order to analyze preferences within neighborhood characteristics. For this purpose, we developed two area measures of deprivation: Geodemographic Index (GDI) and Cultureeconomic Index (CEI). In total n = 9034.75 FTE were included in n = 14 cities with n = 171 districts. FTE were distributed equally on inter-city level (mean: 6.49; range: 5.12-7.20; SD: 0.51). However, on intra-city level, GP distribution was skewed (mean: 6.54; range: 1.80-43.98; SD: 3.62). Distribution patterns of FTE per 10^4 residents were significantly correlated with GDI (r = -0.49; p < 0.001) and CEI (r = -0.22; p = 0.005). Therefore, location choices of GPs were mainly positively correlated with 1) central location (r = -0.50; p < 0.001), 2) small household size of population (r = -0.50; p < 0.001) and 3) population density (r = 0.35; p < 0.001). Intra-city distribution of GPs was skewed, which could affect the equality of access for the urban population. Furthermore, health services planners should be aware of GP location preferences. This could be helpful to better understand and plan delivery of health services. Within this process the presented Geodemographic Index (GDI) could be of use.

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.

Mapping of Titan: Results from the first Titan radar passes

USGS Publications Warehouse

Stofan, E.R.; Lunine, J.I.; Lopes, R.; Paganelli, F.; Lorenz, R.D.; Wood, C.A.; Kirk, R.; Wall, S.; Elachi, C.; Soderblom, L.A.; Ostro, S.; Janssen, M.; Radebaugh, J.; Wye, L.; Zebker, H.; Anderson, Y.; Allison, M.; Boehmer, R.; Callahan, P.; Encrenaz, P.; Flamini, E.; Francescetti, G.; Gim, Y.; Hamilton, G.; Hensley, S.; Johnson, W.T.K.; Kelleher, K.; Muhleman, D.; Picardi, G.; Posa, F.; Roth, L.; Seu, R.; Shaffer, S.; Stiles, B.; Vetrella, S.; West, R.

2006-01-01

The first two swaths collected by Cassini's Titan Radar Mapper were obtained in October of 2004 (Ta) and February of 2005 (T3). The Ta swath provides evidence for cryovolcanic processes, the possible occurrence of fluvial channels and lakes, and some tectonic activity. The T3 swath has extensive areas of dunes and two large impact craters. We interpret the brightness variations in much of the swaths to result from roughness variations caused by fracturing and erosion of Titan's icy surface, with additional contributions from a combination of volume scattering and compositional variations. Despite the small amount of Titan mapped to date, the significant differences between the terrains of the two swaths suggest that Titan is geologically complex. The overall scarcity of impact craters provides evidence that the surface imaged to date is relatively young, with resurfacing by cryovolcanism, fluvial erosion, aeolian erosion, and likely atmospheric deposition of materials. Future radar swaths will help to further define the nature of and extent to which internal and external processes have shaped Titan's surface. ?? 2006 Elsevier Inc. All rights reserved.

Spatial variations in larch needle and soil δ15N at a forest-grassland boundary in northern Mongolia.

PubMed

Fujiyoshi, Lei; Sugimoto, Atsuko; Tsukuura, Akemi; Kitayama, Asami; Lopez Caceres, M Larry; Mijidsuren, Byambasuren; Saraadanbazar, Ariunaa; Tsujimura, Maki

2017-03-01

The spatial patterns of plant and soil δ 15 N and associated processes in the N cycle were investigated at a forest-grassland boundary in northern Mongolia. Needles of Larix sibirica Ledeb. and soils collected from two study areas were analysed to calculate the differences in δ 15 N between needle and soil (Δδ 15 N). Δδ 15 N showed a clear variation, ranging from -8 ‰ in the forest to -2 ‰ in the grassland boundary, and corresponded to the accumulation of organic layer. In the forest, the separation of available N produced in the soil with 15 N-depleted N uptake by larch and 15 N-enriched N immobilization by microorganisms was proposed to cause large Δδ 15 N, whereas in the grassland boundary, small Δδ 15 N was explained by the transport of the most available N into larch. The divergence of available N between larch and microorganisms in the soil, and the accumulation of diverged N in the organic layer control the variation in Δδ 15 N.

Mate choice for genetic quality when environments vary: suggestions for empirical progress.

PubMed

Bussière, Luc F; Hunt, John; Stölting, Kai N; Jennions, Michael D; Brooks, Robert

2008-09-01

Mate choice for good-genes remains one of the most controversial evolutionary processes ever proposed. This is partly because strong directional choice should theoretically deplete the genetic variation that explains the evolution of this type of female mating preference (the so-called lek paradox). Moreover, good-genes benefits are generally assumed to be too small to outweigh opposing direct selection on females. Here, we review recent progress in the study of mate choice for genetic quality, focussing particularly on the potential for genotype by environment interactions (GEIs) to rescue additive genetic variation for quality, and thereby resolve the lek paradox. We raise five questions that we think will stimulate empirical progress in this field, and suggest directions for research in each area: (1) How is condition-dependence affected by environmental variation? (2) How important are GEIs for maintaining additive genetic variance in condition? (3) How much do GEIs reduce the signalling value of male condition? (4) How does GEI affect the multivariate version of the lek paradox? (5) Have mating biases for high-condition males evolved because of indirect benefits?

The aggressive call of Dendropsophus cruzi (Pombal Bastos, 1998) (Anura; Hylidae) in Central Brazil.

PubMed

Andreani, Tainà Lucas; Oliveira, Seixas Rezende; Guerra, VinÍcius; Bastos, RogÉrio Pereira; De Morais, Alessandro Ribeiro

2018-02-13

Dendropsophus cruzi (Pombal Bastos, 1998) is a small hylid (male snout-to-vent length = 16.3-19.4 mm; female SVL = 21.3-25.0 mm) that is allocated in the D. microcephalus group (Faivovich et al. 2005). It is commonly found in Open and forested areas from Central Brazil to Provincia Velasco, Departamento de Santa Cruz, Bolivia (Frost 2017; Tessarolo et al. 2016). Pombal Bastos (1998) described the advertisement call of D. cruzi as a single pulsed note. Posteriorly, studies uncovered relationships between dominant frequency variation in the advertisement calls of D. cruzi and variation in the SVL and mass of males (Bastos et al. 2003), as well as the existence of a clinal geographic pattern in the variation of acoustic parameters of these calls (Tessarolo et al. 2016). However, the acoustic communication in anurans is usually mediated by more than one vocalization type (Toledo et al. 2015). Due the importance of call types in the social context of anurans (e.g., Reichert 2011; Forti et al. 2017), we expand the vocal repertoire of D. cruzi by describing its aggressive call.

Small-scale variation in ecosystem CO2 fluxes in an alpine meadow depends on plant biomass and species richness.

PubMed

Hirota, Mitsuru; Zhang, Pengcheng; Gu, Song; Shen, Haihua; Kuriyama, Takeo; Li, Yingnian; Tang, Yanhong

2010-07-01

Characterizing the spatial variation in the CO2 flux at both large and small scales is essential for precise estimation of an ecosystem's CO2 sink strength. However, little is known about small-scale CO2 flux variations in an ecosystem. We explored these variations in a Kobresia meadow ecosystem on the Qinghai-Tibetan plateau in relation to spatial variability in species composition and biomass. We established 14 points and measured net ecosystem production (NEP), gross primary production (GPP), and ecosystem respiration (Re) in relation to vegetation biomass, species richness, and environmental variables at each point, using an automated chamber system during the 2005 growing season. Mean light-saturated NEP and GPP were 30.3 and 40.5 micromol CO2 m(-2) s(-1) [coefficient of variation (CV), 42.7 and 29.4], respectively. Mean Re at 20 degrees C soil temperature, Re(20), was -10.9 micromol CO2 m(-2) s(-1) (CV, 27.3). Re(20) was positively correlated with vegetation biomass. GPP(max) was positively correlated with species richness, but 2 of the 14 points were outliers. Vegetation biomass was the main determinant of spatial variation of Re, whereas species richness mainly affected that of GPP, probably reflecting the complexity of canopy structure and light partitioning in this small grassland patch.

Assessing spatial associations between thermal stress and mortality in Hong Kong: a small-area ecological study.

PubMed

Thach, Thuan-Quoc; Zheng, Qishi; Lai, Poh-Chin; Wong, Paulina Pui-Yun; Chau, Patsy Yuen-Kwan; Jahn, Heiko J; Plass, Dietrich; Katzschner, Lutz; Kraemer, Alexander; Wong, Chit-Ming

2015-01-01

Physiological equivalent temperature (PET) is a widely used index to assess thermal comfort of the human body. Evidence on how thermal stress-related health effects vary with small geographical areas is limited. The objectives of this study are (i) to explore whether there were significant patterns of geographical clustering of thermal stress as measured by PET and mortality and (ii) to assess the association between PET and mortality in small geographical areas. A small area ecological cross-sectional study was conducted at tertiary planning units (TPUs) level. Age-standardized mortality rates (ASMR) and monthly deaths at TPUs level for 2006 were calculated for cause-specific diseases. A PET map with 100 m × 100 m resolution for the same period was derived from Hong Kong Urban Climatic Analysis Map data and the annual and monthly averages of PET for each TPU were computed. Global Moran's I and local indicator of spatial association (LISA) analyses were performed. A generalized linear mixed model was used to model monthly deaths against PET adjusted for socio-economic deprivation. We found positive spatial autocorrelation between PET and ASMR. There were spatial correlations between PET and ASMR, particularly in the north of Hong Kong Island, most parts of Kowloon, and across New Territories. A 1°C change in PET was associated with an excess risk (%) of 2.99 (95% CI: 0.50-5.48) for all natural causes, 4.75 (1.14-8.36) for cardiovascular, 7.39 (4.64-10.10) for respiratory diseases in the cool season, and 4.31 (0.12 to 8.50) for cardiovascular diseases in the warm season. Variations between TPUs in PET had an important influence on cause-specific mortality, especially in the cool season. PET may have an impact on the health of socio-economically deprived population groups. Our results suggest that targeting policy interventions at high-risk areas may be a feasible option for reducing PET-related mortality. Copyright © 2014 Elsevier B.V. All rights reserved.

Ocean Processes Revealing by Seasonal Dynamics of Surface Chlorophyll Concentration (by Satellite Data)

NASA Astrophysics Data System (ADS)

Shevyrnogov, Anatoly; Vysotskaya, Galina

Continuous monitoring of phytopigment concentrations in the ocean by space-borne methods makes possible to estimate ecological condition of biocenoses in critical areas. Unlike land vege-tation, hydrological processes largely determine phytoplankton dynamics, which may be either recurrent or random. The types of chlorophyll concentration dynamics can manifest as zones quasistationary by seasonal chlorophyll dynamics, perennial variations of phytopigment con-centrations, anomalous variations, etc., that makes possible revealing of hydrological structure of the ocean. While large-scale and frequently occurring phenomena have been much studied, the seldom-occurring changes of small size may be of interest for analysis of long-term processes and rare natural variations. Along with this, the ability to reflect consequences of anthropoge-nous impact or natural ecological disasters on the ocean biota makes the anomalous variations ecologically essential. Civilization aspiring for steady development and preservation of the bio-sphere, must have the knowledge of spatial distribution, seasonal dynamics and anomalies of the primary production process on the planet. In the papers of the authors (Shevyrnogov A.P., Vysotskaya G.S., Gitelzon J.I. Quasistationary areas of chlorophyll concentration in the world ocean as observed satellite data. Adv. Space Res. Vol. 18, No. 7, pp. 129-132, 1996) existence of zones, which are quasi-stationary with similar seasonal dynamics of chlorophyll concentration at surface layer of ocean, was shown. Results were obtained on the base of pro-cessing of time series of satellite images SeaWiFS. It was shown that fronts and frontal zones coincide with dividing lines between quasi-stationary areas, especially in areas of large oceanic streams. Biota of surface oceanic layer is more stable in comparison with quickly changing sur-face temperature. It gives a possibility to circumvent influence of high-frequency component (for example, a diurnal cycle) in investigation of dynamics of spatial distribution of surface streams. In addition, an analyses of nonstable ocean productivity phenomena, stood out time series of satellite images, showed existence of areas with different types of instability in the all Global ocean. They are observed as adjacent nonstationary zones of different size, which are associated by different ways with known oceanic phenomena. It is evident that dynamics of a spatial distribution of biological productivity can give an additional knowledge of complicated picture of surface oceanic layer hydrology.

PROTON MICROPROBE ANALYSIS OF TRACE-ELEMENT VARIATIONS IN VITRINITES IN THE SAME AND DIFFERENT COAL BEDS.

USGS Publications Warehouse

Minkin, J.A.; Chao, E.C.T.; Blank, Herma; Dulong, F.T.

1987-01-01

The PIXE (proton-induced X-ray emission) microprobe can be used for nondestructive, in-situ analyses of areas as small as those analyzed by the electron microprobe, and has a sensitivity of detection as much as two orders of magnitude better than the electron microprobe. Preliminary studies demonstrated that PIXE provides a capability for quantitative determination of elemental concentrations in individual coal maceral grains with a detection limit of 1-10 ppm for most elements analyzed. Encouraged by the earlier results, we carried out the analyses reported below to examine trace element variations laterally (over a km range) as well as vertically (cm to m) in the I and J coal beds in the Upper Cretaceous Ferron Sandstone Member of the Mancos Shale in central Utah, and to compare the data with the data from two samples of eastern coals of Pennsylvanian age.

Population Genetics of Trypanosoma evansi from Camel in the Sudan

PubMed Central

Salim, Bashir; de Meeûs, Thierry; Bakheit, Mohammed A.; Kamau, Joseph; Nakamura, Ichiro; Sugimoto, Chihiro

2011-01-01

Genetic variation of microsatellite loci is a widely used method for the analysis of population genetic structure of microorganisms. We have investigated genetic variation at 15 microsatellite loci of T. evansi isolated from camels in Sudan and Kenya to evaluate the genetic information partitioned within and between individuals and between sites. We detected a strong signal of isolation by distance across the area sampled. The results also indicate that either, and as expected, T. evansi is purely clonal and structured in small units at very local scales and that there are numerous allelic dropouts in the data, or that this species often sexually recombines without the need of the “normal” definitive host, the tsetse fly or as the recurrent immigration from sexually recombined T. brucei brucei. Though the first hypothesis is the most likely, discriminating between these two incompatible hypotheses will require further studies at much localized scales. PMID:21666799

Total Variation Denoising and Support Localization of the Gradient

NASA Astrophysics Data System (ADS)

Chambolle, A.; Duval, V.; Peyré, G.; Poon, C.

2016-10-01

This paper describes the geometrical properties of the solutions to the total variation denoising method. A folklore statement is that this method is able to restore sharp edges, but at the same time, might introduce some staircasing (i.e. “fake” edges) in flat areas. Quite surprisingly, put aside numerical evidences, almost no theoretical result are available to backup these claims. The first contribution of this paper is a precise mathematical definition of the “extended support” (associated to the noise-free image) of TV denoising. This is intuitively the region which is unstable and will suffer from the staircasing effect. Our main result shows that the TV denoising method indeed restores a piece-wise constant image outside a small tube surrounding the extended support. Furthermore, the radius of this tube shrinks toward zero as the noise level vanishes and in some cases, an upper bound on the convergence rate is given.

Applications of thermal remote sensing to detailed ground water studies

NASA Technical Reports Server (NTRS)

Souto-Maior, J.

1973-01-01

Three possible applications of thermal (8-14 microns) remote sensing to detailed hydrogeologic studies are discussed in this paper: (1) the direct detection of seeps and springs, (2) the indirect evaluation of shallow ground water flow through its thermal effects on the land surface, and (3) the indirect location of small volumes of ground water inflow into surface water bodies. An investigation carried out with this purpose in an area containing a complex shallow ground water flow system indicates that the interpretation of the thermal imageries is complicated by many factors, among which the most important are: (1) altitude, angle of view, and thermal-spatial resolution of the sensor; (2) vegetation type, density, and vigor; (3) topography; (4) climatological and micrometeorological effects; (5) variation in soil type and soil moisture; (6) variation in volume and temperature of ground water inflow; (7) the hydraulic characteristics of the receiving water body, and (8) the presence of decaying organic material.

Utilization of environmentally acquired very small particles as a means of association.

PubMed

Stoney, David A; Bowen, Andrew M; Stoney, Paul L

2015-09-01

Very small particles (VSP) are ubiquitous in our environment and are virtually ignored by forensic science. These particles range in size from an order of magnitude smaller than conventional trace evidence, down to the molecular level. Combinations of VSP provide an extraordinary, largely untapped resource for forensic associations and source attribution. This paper describes an initial effort to exploit VSP for one specific application. An approach was developed and tested for the SEM/EDS analysis of VSP recovered from the surfaces of carpet fibers - one of the most common types of trace evidence examined in crime laboratories. Our goal was to exploit existing computer-assisted SEM/EDS methods to test whether VSP profiles could be useful to associate shed fibers with a source carpet. Particles were harvested by washing and filtration onto polycarbonate filters. An SEM/EDS analysis protocol currently employed for environmental particle analyses was used, resulting in individual particle characterization based on fitting to reference spectra of 28 elements. Target Particle Types were defined based on the most abundant elemental profiles and used to bin the results for each specimen, resulting in a Target Particle Type profile. Within-carpet variability was assessed using Target Particle Type profiles from three different areas on each of nine carpets. Area profiles, defined from sets of ten fibers, were compared to profiles from individual fibers. Between-item variation was explored using a survey of an additional 12 carpets. Hundreds to thousands of VSP were found to routinely occur on individual carpet fibers. Their quantity and character was sufficient to associate fibers with their area of origin. Within-carpet variations showed roughly even distributions for most TPTs and between-carpet variations showed wide ranges in types and quantities of VSP. Environmentally acquired VSP showed clear potential to provide quantitative means to link carpet fibers with their area of origin. This finding is noteworthy, since such particles are acquired post-manufacture and are independent of characteristics determined by manufacture. More generally, VSP are ubiquitous, present on or in virtually any item, and there is the potential for linkages among items of any type based on adhering VSP. By way of example, the present work provides impetus for a fundamental change in the way that forensic trace evidence is conceptualized. Further fundamental research is indicated to better understand the underlying variability, usefulness and limitations of this approach. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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.

Accuracy of 1D microvascular flow models in the limit of low Reynolds numbers.

PubMed

Pindera, Maciej Z; Ding, Hui; Athavale, Mahesh M; Chen, Zhijian

2009-05-01

We describe results of numerical simulations of steady flows in tubes with branch bifurcations using fully 3D and reduced 1D geometries. The intent is to delineate the range of validity of reduced models used for simulations of flows in microcapillary networks, as a function of the flow Reynolds number Re. Results from model problems indicate that for Re less than 1 and possibly as high as 10, vasculatures may be represented by strictly 1D Poiseuille flow geometries with flow variation in the axial dimensions only. In that range flow rate predictions in the different branches generated by 1D and 3D models differ by a constant factor, independent of Re. When the cross-sectional areas of the branches are constant these differences are generally small and appear to stem from an uncertainty of how the individual branch lengths are defined. This uncertainty can be accounted for by a simple geometrical correction. For non-constant cross-sections the differences can be much more significant. If additional corrections for the presence of branch junctions and flow area variations are not taken into account in 1D models of complex vasculatures, the resultant flow predictions should be interpreted with caution.

Evaluation of a spatially-distributed Thornthwaite water-balance model

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

Lough, J.A.

1993-03-01

A small watershed of low relief in coastal New Hampshire was divided into hydrologic sub-areas in a geographic information system on the basis of soils, sub-basins and remotely-sensed landcover. Three variables were spatially modeled for input to 49 individual water-balances: available water content of the root zone, water input and potential evapotranspiration (PET). The individual balances were weight-summed to generate the aggregate watershed-balance, which saw 9% (48--50 mm) less annual actual-evapotranspiration (AET) compared to a lumped approach. Analysis of streamflow coefficients suggests that the spatially-distributed approach is more representative of the basin dynamics. Variation of PET by landcover accounted formore » the majority of the 9% AET reduction. Variation of soils played a near-negligible role. As a consequence of the above points, estimates of landcover proportions and annual PET by landcover are sufficient to correct a lumped water-balance in the Northeast. If remote sensing is used to estimate the landcover area, a sensor with a high spatial resolution is required. Finally, while the lower Thornthwaite model has conceptual limitations for distributed application, the upper Thornthwaite model is highly adaptable to distributed problems and may prove useful in many earth-system models.« less

Social inequality and ethnic differences in smoking in New Zealand.

PubMed

Barnett, Ross; Moon, Graham; Kearns, Robin

2004-07-01

This study tests a generalisation of the 'Wilkinson' thesis that the greater a nation's income inequality, the poorer the average national health status. We consider the effect of socio-economic inequality upon ethnic variations in smoking in New Zealand. Analysis of Maori and Pakeha (New Zealanders of European descent) smoking rates from the 1996 Census is conducted for 73 Territorial Local Authority areas in New Zealand, disaggregated by gender and rural-urban location. Partial correlation is used to control for absolute levels of deprivation and examine the independent effect of ethnic social inequality upon smoking rates. The level of social inequality between Maori and Pakeha has an independent effect on Maori smoking rates. Pakeha smoking rates by contrast are more sensitive to variations in absolute rather than relative deprivation. The effect of inequality is greatest for Maori women, especially among urban residents. By contrast, among Maori men the effects are greatest in rural areas. The results provide some qualified support for the Wilkinson thesis and suggest that policies which address fundamental issues of social inequality will play a small, but significant, role in helping to reduce high smoking rates amongst Maori. Copyright 2003 Elsevier Ltd.

Research for Preseismic Phenomena on the Underground Water Level and Temperature in Selected Areas of Greece

NASA Astrophysics Data System (ADS)

Contadakis, M. E.; Asteriadis, G.

1997-08-01

A comprehensive study of the tectonic activity require the contribution of a variety of methods, geological, seismic, geodetic, satellite etc., being currently available in our days. On the other hand, the risk evaluation in areas of high seismicity, like this one of the South Balkan Peninsula, is of vital importance. To this purpose an interdisciplinary following up of the tectonic activity in the area may provide the best provision to the administration for an effective confrontation and intervention for the elimination of the possible disastrous effects in human life cost, financial and social cost of the communities, to which may result a strong earthquake. Among the various methods of indirect monitoring of the tectonic activity in an area, which in addition is of a low cost, is that of the following up of the underground water level and temperature changes in the area of interest. This method is based on the fact that tectonic activity is expected to result to tectonic stresses producing alterations to the local water table which in its turn is expected is expected to be observed as variation of the underground water level and temperature. The method of the following up of the underground water and temperature changes has been applied, among others by the Department of Geodesy and Surveying of the University of Thessaloniki in two areas of high seismicity in Greece: (a) The seismic zone of the lake Volvi in North Greece (40.5 deg N and 23.5 deg E) for ten years (1983-1992) and (b) the area of South Thessaly (39.2 deg N and 21 deg E) for three years (1994-1996). The statistical analysis of the observations, shows that the low frequency constituent (Sa,Ssa,Mf,Mm) of the earth tides and the barometric pressure have a small influence on the water level measurements. The shallow underground water network of South Thessaly is more sensitive to the non tectonic factors than the network of Volvi. Tentative correlation of the underground wat! er and temperature variations with the earthquake indicate that the shocks with magnitude higher than 2.0 can be tentatively connected with water and level or temperature variations in at least one well of the network with a probability higher than 75% in both areas.

Hydrogeology, water resources, and water budget of the upper Rio Hondo Basin, Lincoln County, New Mexico, 2010

USGS Publications Warehouse

Darr, Michael J.; McCoy, Kurt J.; Rattray, Gordon W.; Durall, Roger A.

2014-01-01

The upper Rio Hondo Basin occupies a drainage area of 585 square miles in south-central New Mexico and comprises three general hydrogeologic terranes: the higher elevation “Mountain Block,” the “Central Basin” piedmont area, and the lower elevation “Hondo Slope.” As many as 12 hydrostratigraphic units serve as aquifers locally and form a continuous aquifer on the regional scale. Streams and aquifers in the basin are closely interconnected, with numerous gaining and losing stream reaches across the study area. In general, the aquifers are characterized by low storage capacity and respond to short-term and long-term variations in recharge with marked water-level fluctuations on short (days to months) and long (decadal) time scales. Droughts and local groundwater withdrawals have caused marked water-table declines in some areas, whereas periodically heavy monsoons and snowmelt events have rapidly recharged aquifers in some areas. A regional-scale conceptual water budget was developed for the study area in order to gain a basic understanding of the magnitude of the various components of input, output, and change in storage. The primary input is watershed yield from the Mountain Block terrane, supplying about 38,200 to 42,300 acre-feet per year (acre-ft/yr) to the basin, as estimated by comparing the residual of precipitation and evapotranspiration with local streamgage data. Streamflow from the basin averaged about 21,200 acre-ft/yr, and groundwater output left the basin at an estimated 2,300 to 5,700 acre-ft/yr. The other major output (about 13,500 acre-ft/yr) was by public water supply, private water supply, livestock, commercial and industrial uses, and the Bonito Pipeline. The residual in the water budget, the difference between the totals of the input and output terms or the potential change in storage, ranged from -2,200 acre-ft/yr to +5,300 acre-ft/yr. There is a high degree of variability in precipitation and consequently in the water supply; small variations in annual precipitation can result in major changes in overall watershed yield. Changing water-use patterns, concentrated areas of groundwater withdrawal, and variations in precipitation have created localized areas where water-table declines and diminished surface flow are of concern.

LACIE analyst interpretation keys

NASA Technical Reports Server (NTRS)

Baron, J. G.; Payne, R. W.; Palmer, W. F. (Principal Investigator)

1979-01-01

Two interpretation aids, 'The Image Analysis Guide for Wheat/Small Grains Inventories' and 'The United States and Canadian Great Plains Regional Keys', were developed during LACIE phase 2 and implemented during phase 3 in order to provide analysts with a better understanding of the expected ranges in color variation of signatures for individual biostages and of the temporal sequences of LANDSAT signatures. The keys were tested using operational LACIE data, and the results demonstrate that their use provides improved labeling accuracy in all analyst experience groupings, in all geographic areas within the U.S. Great Plains, and during all periods of crop development.

Design of analog pixels front-end active feedback

NASA Astrophysics Data System (ADS)

Kmon, P.; Kadlubowski, L. A.; Kaczmarczyk, P.

2018-01-01

The paper presents the design of the active feedback used in a charge-sensitive amplifier. The predominant advantages of the presented circuit are its ability for setting wide range of pulse-time widths, small silicon area occupation and low power consumption. The feedback also allows sensor leakage current compensation and, thanks to an additional DC amplifier, it minimizes the output DC voltage variations, which is especially important in the DC coupled recording chain and for processes with limited supply voltage. The paper provides feedback description and its operation principle. The proposed circuit was designed in the CMOS 130nm technology.

A dehydration mechanism for the stratosphere

NASA Technical Reports Server (NTRS)

Danielsen, E. F.

1982-01-01

Although mean circulations are generally credited with dehydration of the earth's stratosphere, convective instability in the tropics converts mean circulations to small residuals of local convective circulations. The effects of large cumulonimbus which penetrate the stratosphere and form huge anvils in the lower stratosphere are discussed with respect to hydration and dehydration of the stratosphere. Radiative heating at anvil base combined with cooling at anvil top drives a dehydration engine considered essential to explain the dry stratosphere. Seasonal and longitudinal variations in dehydration potentials are examined with maximum potential attributed to Micronesian area during winter and early spring.

Genetic diversity and population differentiation of small giant clam Tridacna maxima in Comoros islands assessed by microsatellite markers.

PubMed

Ahmed Mohamed, Nadjim; Yu, Qian; Chanfi, Mohamed Ibrahim; Li, Yangping; Wang, Shi; Huang, Xiaoting; Bao, Zhenmin

2016-01-01

Small giant clam, Tridacna maxima , widely distributed from French Polynesia to East Africa, has faced population declines due to over-exploitation. Comoros islands are an important biogeographic region due to potential richness of marine species, but no relevant information is available. In order to facilitate devising effective conservation management plan for T. maxima , nine microsatellite markers were used to survey genetic diversity and population differentiation of 72 specimens collected from three Comoros islands, Grande Comore, Moheli and Anjouan. A total of 51 alleles were detected ranged from 2 to 8 per locus. Observed and expected heterozygosity varied from 0.260 to 0.790 and from 0.542 to 0.830, respectively. All populations have high genetic diversity, especially the population in Moheli, a protected area, has higher genetic diversity than the others. Significant heterozygote deficiencies were recorded, and null alleles were probably the main factor leading to these deficits. F ST value indicated medium genetic differentiation among the populations. Although significant, AMOVA revealed 48.9 % of genetic variation within individuals and only a small variation of 8.9 % was found between populations. Gene flow was high ( Nm  = 12.40) between Grande Comore and Moheli, while lower ( Nm  = 1.80) between Grande Comore and Anjouan, explaining geographic barriers to genetic exchanges might exist in these two islands. Global gene flow analysis ( Nm  = 5.50) showed that larval dispersal is enough to move between the islands. The high genetic diversity and medium population differentiation revealed in the present study offer useful information on genetic conservation of small giant clams.

Variability in Soil Properties at Different Spatial Scales (1 m to 1 km) in a Deciduous Forest Ecosystem

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

Garten Jr, Charles T; Kang, S.; Brice, Deanne Jane

2007-01-01

The purpose of this research was to test the hypothesis that variability in 11 soil properties, related to soil texture and soil C and N, would increase from small (1 m) to large (1 km) spatial scales in a temperate, mixed-hardwood forest ecosystem in east Tennessee, USA. The results were somewhat surprising and indicated that a fundamental assumption in geospatial analysis, namely that variability increases with increasing spatial scale, did not apply for at least five of the 11 soil properties measured over a 0.5-km2 area. Composite mineral soil samples (15 cm deep) were collected at 1, 5, 10, 50,more » 250, and 500 m distances from a center point along transects in a north, south, east, and westerly direction. A null hypothesis of equal variance at different spatial scales was rejected (P{le}0.05) for mineral soil C concentration, silt content, and the C-to-N ratios in particulate organic matter (POM), mineral-associated organic matter (MOM), and whole surface soil. Results from different tests of spatial variation, based on coefficients of variation or a Mantel test, led to similar conclusions about measurement variability and geographic distance for eight of the 11 variables examined. Measurements of mineral soil C and N concentrations, C concentrations in MOM, extractable soil NH{sub 4}-N, and clay contents were just as variable at smaller scales (1-10 m) as they were at larger scales (50-500 m). On the other hand, measurement variation in mineral soil C-to-N ratios, MOM C-to-N ratios, and the fraction of soil C in POM clearly increased from smaller to larger spatial scales. With the exception of extractable soil NH4-N, measured soil properties in the forest ecosystem could be estimated (with 95% confidence) to within 15% of their true mean with a relatively modest number of sampling points (n{le}25). For some variables, scaling up variation from smaller to larger spatial domains within the ecosystem could be relatively easy because small-scale variation may be indicative of variation at larger scales.« less

The geometry and lithology of the Cima Sandstone Lentil: a paleoseep-bearing interbed in the Moreno Formation, central California

NASA Astrophysics Data System (ADS)

Wheatley, P. V.; Schwartz, H.

2007-12-01

The Cima Sandstone Lentil outcrops over a relatively small area on the western side of the San Joaquin Valley in central California. Here this unit can be found in the Panoche Hills in the northern portion of the field area and the Tumey Hills in the southern portion of the field area. The Cima Sandstone resides within the 800m Moreno Formation that spans the Maastrichtian to the Danian. The Moreno Formation comprises four members, which are the Dosados Member, the Tierra Loma Member, the Marca Shale Member, and the Dos Palos Shale Member (of which the Cima Sandstone is an interbed). The Cima Sandstone contains numerous large carbonate mounds, concretions, and pavements, indicating paleoseep activity. The Cima Sandstone has never been studied in detail, but recent interest in sandstone injectites as well as interest in paleoseeps has prompted us to examine this interbed more carefully. The Cima is an immature sandstone composed primarily of quartz along with small amounts of micas and feldspars as well as varying amounts of glauconite. These minerals are generally cemented by carbonate but, occasionally, iron oxide cement is present locally. Much variation exists within the Cima Sandstone Lentil and we seek to characterize and understand this variation. One of the most obvious sources of variability is the thickness of the unit itself. The thickness ranges from near 60m in the northern Panoche Hills to only 9m in the Tumey Hills. Induration also varies noticeably, from well cemented in the north, to unconsolidated in the south. Similarly, the sandstone is grain-supported and houses some depositional structures in the northern outcrops but becomes largely matrix-supported and lacking bedding in the southern outcrops. Preliminary data suggests that proximity to carbonate concretions, fluid conduits, and underlying injectites may have some influence over grain size and sorting.

Sunspots, Starspots, and Elemental Abundances

NASA Astrophysics Data System (ADS)

Doschek, George A.; Warren, Harry P.

2017-08-01

The composition of plasma in solar and stellar atmospheres is not fixed, but varies from feature to feature. These variations are organized by the First Ionization Potential (FIP) of the element. Solar measurements often indicate that low FIP elements (< 10eV, such as Fe, Si, Mg) are enriched by factors of 3-4 in the corona relative to high FIP elements (>10 eV, such as C, N, O, Ar, He) compared to abundances in the photosphere. Stellar observations have also shown similar enrichments. An inverse FIP effect, where the low FIP elements are depleted, has been observed in stellar coronae of stars believed to have large starspots in their photospheres. The abundances are important for determining radiative loss rates in models, tracing the origin of the slow solar wind, and for understanding wave propagation in the chromosphere and corona. Recently, inverse FIP effects have been discovered in the Sun (Doschek, Warren, & Feldman 2015, ApJ, 808, L7) from spectra obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. The inverse FIP regions seem always to be near sunspots and cover only a very small area (characteristic length = a few arcseconds). However, in pursuing the search for inverse FIP regions, we have found that in some sunspot groups the coronal abundance at a temperature of 3-4 MK can be near photospheric over much larger areas of the sun near the sunspots (e.g., 6,000 arcsec2). Also, sometimes the abundances at 3-4 MK are in between coronal and photospheric values. This can occur in small areas of an active region. It is predicted (Laming 2015, Sol. Phys., 12, 2) that the FIP effect should be highly variable in the corona. Several examples of coronal abundance variations are presented. Our work indicates that a comprehensive re-investigation of solar abundances is highly desirable. This work is supported by a NASA Hinode grant.

Screening and Follow-Up Monitoring for Substance Use in Primary Care: An Exploration of Rural-Urban Variations.

PubMed

Chan, Ya-Fen; Lu, Shou-En; Howe, Bill; Tieben, Hendrik; Hoeft, Theresa; Unützer, Jürgen

2016-02-01

Rates of substance use in rural areas are close to those of urban areas. While recent efforts have emphasized integrated care as a promising model for addressing workforce shortages in providing behavioral health services to those living in medically underserved regions, little is known on how substance use problems are addressed in rural primary care settings. To examine rural-urban variations in screening and monitoring primary care- based patients for substance use problems in a state-wide mental health integration program. This was an observational study using patient registry. The study included adult enrollees (n = 15,843) with a mental disorder from 133 participating community health clinics. We measured whether a standardized substance use instrument was used to screen patients at treatment entry and to monitor symptoms at follow-up visits. While on average 73.6 % of patients were screened for substance use, follow-up on substance use problems after initial screening was low (41.4 %); clinics in small/isolated rural settings appeared to be the lowest (13.6 %). Patients who were treated for a mental disorder or substance abuse in the past and who showed greater psychiatric complexities were more likely to receive a screening, whereas patients of small, isolated rural clinics and those traveling longer distances to the care facility were least likely to receive follow-up monitoring for their substance use problems. Despite the prevalent substance misuse among patients with mental disorders, opportunities to screen this high-risk population for substance use and provide a timely follow-up for those identified as at risk remained overlooked in both rural and urban areas. Rural residents continue to bear a disproportionate burden of substance use problems, with rural-urban disparities found to be most salient in providing the continuum of services for patients with substance use problems in primary care.

Sociodemographic and health characteristics, rather than primary care supply, are major drivers of geographic variation in preventable hospitalizations in Australia.

PubMed

Falster, Michael O; Jorm, Louisa R; Douglas, Kirsty A; Blyth, Fiona M; Elliott, Robert F; Leyland, Alastair H

2015-05-01

Geographic rates of preventable hospitalization are used internationally as an indicator of accessibility and quality of primary care. Much research has correlated the indicator with the supply of primary care services, yet multiple other factors may influence these admissions. To quantify the relative contributions of the supply of general practitioners (GPs) and personal sociodemographic and health characteristics, to geographic variation in preventable hospitalization. Self-reported questionnaire data for 267,091 participants in the 45 and Up Study, Australia, were linked with administrative hospital data to identify preventable hospitalizations. Multilevel Poisson models, with participants clustered in their geographic area of residence, were used to explore factors that explain geographic variation in hospitalization. GP supply, measured as full-time workload equivalents, was not a significant predictor of preventable hospitalization, and explained only a small amount (2.9%) of the geographic variation in hospitalization rates. Conversely, more than one-third (36.9%) of variation was driven by the sociodemographic composition, health, and behaviors of the population. These personal characteristics explained a greater amount of the variation for chronic conditions (37.5%) than acute (15.5%) or vaccine-preventable conditions (2.4%). Personal sociodemographic and health characteristics, rather than GP supply, are major drivers of preventable hospitalization. Their contribution varies according to condition, and if used for performance comparison purposes, geographic rates of preventable hospitalization should be reported according to individual condition or potential pathways for intervention.

Geomorphic determinants of species composition of alpine tundra, Glacier National Park, U.S.A.

USGS Publications Warehouse

George P. Malanson,; Bengtson, Lindsey E.; Fagre, Daniel B.

2012-01-01

Because the distribution of alpine tundra is associated with spatially limited cold climates, global warming may threaten its local extent or existence. This notion has been challenged, however, based on observations of the diversity of alpine tundra in small areas primarily due to topographic variation. The importance of diversity in temperature or moisture conditions caused by topographic variation is an open question, and we extend this to geomorphology more generally. The extent to which geomorphic variation per se, based on relatively easily assessed indicators, can account for the variation in alpine tundra community composition is analyzed versus the inclusion of broad indicators of regional climate variation. Visual assessments of topography are quantified and reduced using principal components analysis (PCA). Observations of species cover are reduced using detrended correspondence analysis (DCA). A “best subsets” regression approach using the Akaike Information Criterion for selection of variables is compared to a simple stepwise regression with DCA scores as the dependent variable and scores on significant PCA axes plus more direct measures of topography as independent variables. Models with geographic coordinates (representing regional climate gradients) excluded explain almost as much variation in community composition as models with them included, although they are important contributors to the latter. The geomorphic variables in the model are those associated with local moisture differences such as snowbeds. The potential local variability of alpine tundra can be a buffer against climate change, but change in precipitation may be as important as change in temperature.

Sociodemographic and Health Characteristics, Rather Than Primary Care Supply, are Major Drivers of Geographic Variation in Preventable Hospitalizations in Australia

PubMed Central

Jorm, Louisa R.; Douglas, Kirsty A.; Blyth, Fiona M.; Elliott, Robert F.; Leyland, Alastair H.

2015-01-01

Background: Geographic rates of preventable hospitalization are used internationally as an indicator of accessibility and quality of primary care. Much research has correlated the indicator with the supply of primary care services, yet multiple other factors may influence these admissions. Objective: To quantify the relative contributions of the supply of general practitioners (GPs) and personal sociodemographic and health characteristics, to geographic variation in preventable hospitalization. Methods: Self-reported questionnaire data for 267,091 participants in the 45 and Up Study, Australia, were linked with administrative hospital data to identify preventable hospitalizations. Multilevel Poisson models, with participants clustered in their geographic area of residence, were used to explore factors that explain geographic variation in hospitalization. Results: GP supply, measured as full-time workload equivalents, was not a significant predictor of preventable hospitalization, and explained only a small amount (2.9%) of the geographic variation in hospitalization rates. Conversely, more than one-third (36.9%) of variation was driven by the sociodemographic composition, health, and behaviors of the population. These personal characteristics explained a greater amount of the variation for chronic conditions (37.5%) than acute (15.5%) or vaccine-preventable conditions (2.4%). Conclusions: Personal sociodemographic and health characteristics, rather than GP supply, are major drivers of preventable hospitalization. Their contribution varies according to condition, and if used for performance comparison purposes, geographic rates of preventable hospitalization should be reported according to individual condition or potential pathways for intervention. PMID:25793270

Hospital staffing and local pay: an investigation into the impact of local variations in the competitiveness of nurses' pay on the staffing of hospitals in France.

PubMed

Combes, Jean-Baptiste; Delattre, Eric; Elliott, Bob; Skåtun, Diane

2015-09-01

Spatial wage theory suggests that employers in different regions may offer different pay rates to reflect local amenities and cost of living. Higher wages may be required to compensate for a less pleasant environment or a higher cost of living. If wages in a competing sector within an area are less flexible and therefore less competitive this may lead to an inability to employ staff. This paper considers the market for nursing staff in France where there is general regulation of wages and public hospitals compete for staff with the private hospital and non-hospital sectors. We consider two types of nursing staff, registered and assistant nurses and first establish the degree of spatial variation in the competitiveness of pay of nurses in public hospitals. We then consider whether these spatial variations are associated with variation in the employment of nursing staff. We find that despite regulation of pay in the public and private sector, there are substantial local variations in the competitiveness of nurses' pay. We find evidence that the spatial variations in the competitiveness of pay are associated with relative numbers of assistant nurses but not registered nurses. While we find the influence of the competitiveness of pay is small, it suggests that nonpay conditions may be an important factor in adjusting the labour market as might be expected in such a regulated market.

Habitat fragmentation effects on the orchid bee communities in remnant forests of southeastern Brazil.

PubMed

Knoll, Fátima do Rosário Naschenveng; Penatti, N C

2012-10-01

The effect of habitat fragmentation on the structure of orchid bee communities was analyzed by the investigation of the existence of a spatial structure in the richness and abundance of Euglossini species and by determining the relationship between these data and environmental factors. The surveys were carried out in four different forest fragments and one university campus. Richness, abundance, and diversity of species were analyzed in relation to abiotic (size of the area, extent of the perimeter, perimeter/area ratio, and shape index) and biotic characteristics (vegetation index of the fragment and of the matrix of each of the locations studied). We observed a highly significant positive correlation between the diversity index and the vegetation index of the fragment, landscape and shape index. Our analysis demonstrated that the observed variation could be explained mainly by the vegetation index and the size of the fragment. Variations in relative abundance showed a tendency toward an aggregated spatial distribution between the fragments studied, as well as between the sampling stations within the same habitat, demonstrating the existence of a spatial structure on a small scale in the populations of Euglossini. This distribution will determine the composition of species that coexist in the area after fragmentation. These data help in understanding the differences and similarities in the structure of communities of Euglossini resulting from forest fragmentation.

Scale characters analysis for gully structure in the watersheds of loess landforms based on digital elevation models

NASA Astrophysics Data System (ADS)

Zhu, Hongchun; Zhao, Yipeng; Liu, Haiying

2018-04-01

Scale is the basic attribute for expressing and describing spatial entity and phenomena. It offers theoretical significance in the study of gully structure information, variable characteristics of watershed morphology, and development evolution at different scales. This research selected five different areas in China's Loess Plateau as the experimental region and used DEM data at different scales as the experimental data. First, the change rule of the characteristic parameters of the data at different scales was analyzed. The watershed structure information did not change along with a change in the data scale. This condition was proven by selecting indices of gully bifurcation ratio and fractal dimension as characteristic parameters of watershed structure information. Then, the change rule of the characteristic parameters of gully structure with different analysis scales was analyzed by setting the scale sequence of analysis at the extraction gully. The gully structure of the watershed changed with variations in the analysis scale, and the change rule was obvious when the gully level changed. Finally, the change rule of the characteristic parameters of the gully structure at different areas was analyzed. The gully fractal dimension showed a significant numerical difference in different areas, whereas the variation of the gully branch ratio was small. The change rule indicated that the development degree of the gully obviously varied in different regions, but the morphological structure was basically similar.

Scale characters analysis for gully structure in the watersheds of loess landforms based on digital elevation models

NASA Astrophysics Data System (ADS)

Zhu, Hongchun; Zhao, Yipeng; Liu, Haiying

2018-06-01

Scale is the basic attribute for expressing and describing spatial entity and phenomena. It offers theoretical significance in the study of gully structure information, variable characteristics of watershed morphology, and development evolution at different scales. This research selected five different areas in China's Loess Plateau as the experimental region and used DEM data at different scales as the experimental data. First, the change rule of the characteristic parameters of the data at different scales was analyzed. The watershed structure information did not change along with a change in the data scale. This condition was proven by selecting indices of gully bifurcation ratio and fractal dimension as characteristic parameters of watershed structure information. Then, the change rule of the characteristic parameters of gully structure with different analysis scales was analyzed by setting the scale sequence of analysis at the extraction gully. The gully structure of the watershed changed with variations in the analysis scale, and the change rule was obvious when the gully level changed. Finally, the change rule of the characteristic parameters of the gully structure at different areas was analyzed. The gully fractal dimension showed a significant numerical difference in different areas, whereas the variation of the gully branch ratio was small. The change rule indicated that the development degree of the gully obviously varied in different regions, but the morphological structure was basically similar.

The frequency of Th17 cells in the small intestine exhibits a day-night variation dependent on circadian clock activity.

PubMed

Thu Le, Ha Pham; Nakamura, Yuki; Oh-Oka, Kyoko; Ishimaru, Kayoko; Nakajima, Shotaro; Nakao, Atsuhito

2017-08-19

Interleukin-17-producing CD4 + T helper (Th17) cells are a key immune lineage that protects against bacterial and fungal infections at mucosal surfaces. At steady state, Th17 cells are abundant in the small intestinal mucosa of mice. There are several mechanisms for regulating the population of Th17 cells in the small intestine, reflecting the importance of maintaining their numbers in the correct balance. Here we demonstrate the existence of a time-of-day-dependent variation in the frequency of Th17 cells in the lamina propria of the small intestine in wild-type mice, which was not observed in mice with a loss-of-function mutation of the core circadian gene Clock or in mice housed under aberrant light/dark conditions. Consistent with this, expression of CCL20, a chemokine that regulates homeostatic trafficking of Th17 cells to the small intestine, exhibited circadian rhythms in the small intestine of wild-type, but not Clock-mutated, mice. In support of these observations, the magnitude of ovalbumin (OVA)-specific antibody and T-cell responses in mice sensitized with OVA plus cholera toxin, a mucosal Th17 cell-dependent adjuvant, was correlated with daily variations in the proportion of Th17 cells in the small intestine. These results suggest that the proportion of Th17 cells in the small intestine exhibits a day-night variation in association with CCL20 expression, which depends on circadian clock activity. The findings provide novel insight into the regulation of the Th17 cell population in the small intestine at steady state, which may have translational potential for mucosal vaccination strategies. Copyright © 2017 Elsevier Inc. All rights reserved.

Factors associated with plant species richness in a coastal tall-grass prairie

USGS Publications Warehouse

Grace, James B.; Allain, Larry K.; Allen, Charles

2000-01-01

In this study we examine the factors associated with variations in species richness within a remnant tall-grass prairie in order to gain insight into the relative importance of controlling variables. The study area was a small, isolated prairie surrounded by wetlands and located within the coastal prairie region, which occurs along the northwestern Gulf of Mexico coastal plain. Samples were taken along three transects that spanned the prairie. Parameters measured included micro-elevation, soil characteristics, indications of recent disturbance, above-ground biomass (including litter), light penetration through the plant canopy, and species richness. Species richness was found to correlate with micro-elevation, certain soil parameters, and light penetration through the canopy, but not with above-ground biomass. Structural equation analysis was used to assess the direct and indirect effects of micro-elevation, soil properties, disturbance, and indicators of plant abundance on species richness. The results of this analysis showed that observed variations in species richness were primarily associated with variations in environmental effects (from soil and microtopography) and were largely unrelated to variations in measures of plant abundance (biomass and light penetration). These findings suggest that observed variations in species richness in this system primarily resulted from environmental effects on the species pool. These results fit with a growing body of information that suggests that environmental effects on species richness are of widespread importance.

Estimating micro area behavioural risk factor prevalence from large population-based surveys: a full Bayesian approach.

PubMed

Seliske, L; Norwood, T A; McLaughlin, J R; Wang, S; Palleschi, C; Holowaty, E

2016-06-07

An important public health goal is to decrease the prevalence of key behavioural risk factors, such as tobacco use and obesity. Survey information is often available at the regional level, but heterogeneity within large geographic regions cannot be assessed. Advanced spatial analysis techniques are demonstrated to produce sensible micro area estimates of behavioural risk factors that enable identification of areas with high prevalence. A spatial Bayesian hierarchical model was used to estimate the micro area prevalence of current smoking and excess bodyweight for the Erie-St. Clair region in southwestern Ontario. Estimates were mapped for male and female respondents of five cycles of the Canadian Community Health Survey (CCHS). The micro areas were 2006 Census Dissemination Areas, with an average population of 400-700 people. Two individual-level models were specified: one controlled for survey cycle and age group (model 1), and one controlled for survey cycle, age group and micro area median household income (model 2). Post-stratification was used to derive micro area behavioural risk factor estimates weighted to the population structure. SaTScan analyses were conducted on the granular, postal-code level CCHS data to corroborate findings of elevated prevalence. Current smoking was elevated in two urban areas for both sexes (Sarnia and Windsor), and an additional small community (Chatham) for males only. Areas of excess bodyweight were prevalent in an urban core (Windsor) among males, but not females. Precision of the posterior post-stratified current smoking estimates was improved in model 2, as indicated by narrower credible intervals and a lower coefficient of variation. For excess bodyweight, both models had similar precision. Aggregation of the micro area estimates to CCHS design-based estimates validated the findings. This is among the first studies to apply a full Bayesian model to complex sample survey data to identify micro areas with variation in risk factor prevalence, accounting for spatial correlation and other covariates. Application of micro area analysis techniques helps define areas for public health planning, and may be informative to surveillance and research modeling of relevant chronic disease outcomes.

Why natural disaster planning scenarios are often so disastrously wrong.

NASA Astrophysics Data System (ADS)

Verosub, K. L.

2017-12-01

Taken together the four hurricanes that impacted the United States in the summer of 2017 demonstrate the difficulties involved in trying to plan for any natural disaster, not simply a major hurricane. They also highlight the extraordinary degree to which small and/or random variations in initial conditions can have enormous consequences on the outcome of an event and on the ability of a society to respond to it. For example, if Harvey had been moving faster, it would have meant less rainfall and hence less flooding in the Houston area whereas a slight change in the path of Irma would have significantly affected which portions of the Florida peninsula would have experienced greater or lesser devastation. In the case of Marie, hurricane intensity and path as well as the terrain in Puerto Rico and the inherent state of its infrastructure greatly complicated relief and recovery efforts there. An additional factor that makes planning scenarios so difficult to develop is that major natural disasters can often be analyzed as a sequence of events. At each juncture in the sequence, the event might evolve along two or more very different pathways, which can lead to different outcomes. Sometimes, as with Nate, an event evolves more or less "as expected" and the planning scenario does what it was supposed to do, namely, help people respond to the event. But to a much greater extent than is usually recognized, small or random variations can drive an event off its expected trajectory and into a response realm that "no one could have foreseen." Even worse is when those small or random variations allow an event to bifurcate and follow two or more different pathways simultaneously, leading to a cascading disaster that totally overwhelms whatever planning and preparation has been put in place. Perhaps the main lessons to be learned from these storms is that planning for any disaster requires greater recognition of the importance of small or random factors and greater appreciation of the complexity of these events. One plan or one model scenario does not provide adequate preparation for all events of a particular type and is probably unlikely to provide adequate preparation for any single given event.

Is mercury from small-scale gold mining prevalent in the southeastern Peruvian Amazon?

PubMed

Moreno-Brush, Mónica; Rydberg, Johan; Gamboa, Nadia; Storch, Ilse; Biester, Harald

2016-11-01

There is an ongoing debate on the fate of mercury (Hg) in areas affected by artisanal and small-scale gold mining (ASGM). Over the last 30 years, ASGM has released 69 tons of Hg into the southeastern Peruvian Amazon. To investigate the role of suspended matter and hydrological factors on the fate of ASGM-Hg, we analysed riverbank sediments and suspended matter along the partially ASGM-affected Malinowski-Tambopata river system and examined Hg accumulation in fish. In addition, local impacts of atmospheric Hg emissions on aquatic systems were assessed by analysing a sediment core from an oxbow lake. Hg concentrations in riverbank sediments are lower (20-53 ng g -1 ) than in suspended matter (∼400-4000 ng g -1 ) due to differences in particle size. Elevated Hg concentrations in suspended matter from ASGM-affected river sections (∼1400 vs. ∼30-120 ng L -1 in unaffected sections) are mainly driven by the increased amount of suspended matter rather than increased Hg concentrations in the suspended matter. The oxbow lake sediment record shows low Hg concentrations (64-86 ng g -1 ) without evidence of any ASGM-related increase in atmospheric Hg input. Hg flux variations are mostly an effect of variations in sediment accumulation rates. Moreover, only 5% of the analysed fish (only piscivores) exceed WHO recommendations for human consumption (500 ng g -1 ). Our findings show that ASGM-affected river sections in the Malinowski-Tambopata system do not exhibit increased Hg accumulation, indicating that the released Hg is either retained at the spill site or transported to areas farther away from the ASGM areas. We suspect that the fate of ASGM-Hg in such tropical rivers is mainly linked to transport associated with the suspended matter, especially during high water situations. We assume that our findings are typical for ASGM-affected areas in tropical regions and could explain why aquatic systems in such ASGM regions often show comparatively modest enrichment in Hg levels. Copyright © 2016 Elsevier Ltd. All rights reserved.

Female fecundity variation affects reproducibility of experiments on host plant preference and acceptance in a phytophagous insect

PubMed Central

Schäpers, Alexander; Petrén, Hampus; Wheat, Christopher W.; Wiklund, Christer

2017-01-01

Reproducibility is a scientific cornerstone. Many recent studies, however, describe a reproducibility crisis and call for assessments of reproducibility across scientific domains. Here, we explore the reproducibility of a classic ecological experiment—that of assessing female host plant preference and acceptance in phytophagous insects, a group in which host specialization is a key driver of diversification. We exposed multiple cohorts of Pieris napi butterflies from the same population to traditional host acceptance and preference tests on three Brassicaceae host species. Whereas the host plant rank order was highly reproducible, the propensity to oviposit on low-ranked hosts varied significantly even among cohorts exposed to similar conditions. Much variation could be attributed to among-cohort variation in female fecundity, a trait strongly correlated both to female size and to the size of the nuptial gift a female receives during mating. Small males provide small spermatophores, and in our experiment small females that mated with small males had a disproportionally low propensity to oviposit on low-ranked hosts. Hence, our results provide empirical support to the theoretical prediction that female host utilization is strongly affected by non-genetic, environmental variation, and that such variation can affect the reproducibility of ecological experiments even under seemingly identical conditions. PMID:28202813

Spatio-Temporal Variation in Landscape Composition May Speed Resistance Evolution of Pests to Bt Crops.

PubMed

Ives, Anthony R; Paull, Cate; Hulthen, Andrew; Downes, Sharon; Andow, David A; Haygood, Ralph; Zalucki, Myron P; Schellhorn, Nancy A

2017-01-01

Transgenic crops that express insecticide genes from Bacillus thuringiensis (Bt) are used worldwide against moth and beetle pests. Because these engineered plants can kill over 95% of susceptible larvae, they can rapidly select for resistance. Here, we use a model for a pyramid two-toxin Bt crop to explore the consequences of spatio-temporal variation in the area of Bt crop and non-Bt refuge habitat. We show that variability over time in the proportion of suitable non-Bt breeding habitat, Q, or in the total area of Bt and suitable non-Bt habitat, K, can increase the overall rate of resistance evolution by causing short-term surges of intense selection. These surges can be exacerbated when temporal variation in Q and/or K cause high larval densities in refuges that increase density-dependent mortality; this will give resistant larvae in Bt fields a relative advantage over susceptible larvae that largely depend on refuges. We address the effects of spatio-temporal variation in a management setting for two bollworm pests of cotton, Helicoverpa armigera and H. punctigera, and field data on landscape crop distributions from Australia. Even a small proportion of Bt fields available to egg-laying females when refuges are sparse may result in high exposure to Bt for just a single generation per year and cause a surge in selection. Therefore, rapid resistance evolution can occur when Bt crops are rare rather than common in the landscape. These results highlight the need to understand spatio-temporal fluctuations in the landscape composition of Bt crops and non-Bt habitats in order to design effective resistance management strategies.

Temporal variation of phytoplankton in a small tropical crater lake, Costa Rica.

PubMed

Umaña-Villalobos, Gerardo

2010-12-01

The temporal variation in lake's phytoplankton is important to understand its general biodiversity. For tropical lakes, it has been hypothesized that they follow a similar pattern as temperate ones, on a much accelerated pace; nevertheless, few case studies have tried to elucidate this. Most studies in Costa Rica have used a monthly sampling scheme and failed in showing the expected changes. In this study, the phytoplankton of the small Barvas's crater lake was followed for more than three years, first with monthly and later with weekly samplings, that covered almost two years. Additional information on temperature and oxygen vertical profiles was obtained on a monthly basis, and surface temperature was measured during weekly samplings around noon. Results showed that in spite of its shallow condition (max. depth: 7m) and low surface temperature (11 to 19 degrees C), the lake stratifies at least for brief periods. The phytoplankton showed both, rapid change periods, and prolonged ones of relative stasis. The plankton composition fluctuated between three main phases, one characterized by the abundance of small sized desmids (Staurastrum paradoxum, Cosmarium asphaerosporum), a second phase dominated by equally small cryptomonads (Chryptochrysis minor, Chroomonas sp.) and a third phase dominated by the green alga Eutetramorus tetrasporus. Although data evidenced that monthly sampling could miss short term events, the temporal variation did not follow the typical dry and rainy seasons of the region, or any particular annual pattern. Year to year variation was high. As this small lake is located at the summit of Barva Volcano and receives the influence from both the Caribbean and the Pacific weather, seasonality at the lake is not clearly defined as in the rest of the country and short term variations in the local weather might have a stronger effect than broad seasonal trends. The occurrence of this short term changes in the phytoplankton of small tropical lakes in response to weather variations needs to be further explored in other lakes.

Stemflow variation in Mexico's northeastern forest communities: Its contribution to soil moisture content and aquifer recharge

NASA Astrophysics Data System (ADS)

Návar, José

2011-09-01

SummaryStemflow hydro-ecological importance was measured in trees and assessed in Mexico's northeast forest stands by answering three basic questions: (a) what are the intra and inter-specific stemflow variations; (b) is the stemflow coefficient constant from tree level to stand scales? and (c) what is the stemflow area and wetted soil volume in individual trees and the stemflow volume discharged at the stand scale in two plant communities of northeastern Mexico? Gross rainfall and stemflow flux measurements were conducted on 78 trees of semi-arid, sub-tropical (31 Diospyros texana; 14 Acacia rigidula; four Bumelia celastrina; five Condalia hookeri; three Cordia bioissieri; three Pithecellobium pallens) and temperate forest communities (six Pinus pseudostrobus Lindl. and 12 Quercus spp.). Stemflow was extrapolated from individual trees to the stand scale using 98 inventory plots (1600 m 2 ha -1 each) placed in oak-pine forests and 37 quadrats (5 m × 5 m each) distributed across the Tamaulipan thornscrub forest range. Stemflow infiltration flux and infiltration area measurements assessed the wetted soil volume. Daily measurements were conducted from May of 1997 to November of 1998. Results showed that stemflow coefficients varied between plant communities since they averaged (confidence intervals, α = 0.05) 2.49% (0.57), 0.30% (0.09), and 0.77% (0.27) of the bulk precipitation for Tamaulipan thornscrub, pine, and oak forests, respectively. Intra-specific stemflow variations could not be identified in Tamaulipan although in temperate tree species. Basal diameter explained intra-specific stemflow variation in both plant communities. Stemflow increased threefold since it accounted for by 6.38% and 2.19% of the total bulk rainfall for Tamaulipan thornscrub quadrats and temperate oak-pine inventory plots, respectively. Small shrubs growing underneath large trees, in combination with the presence of small-diameter trees that recorded the largest stemflow coefficients appear to explain the increase of the stemflow coefficient from trees to stands. Stemflow replenishes soil moisture on the average 4.5 (1.4) times larger than does incident rainfall in open soils and appear to contribute to aquifer recharge in temperate forests due to a combination of shallow soils, high infiltration fluxes and the stemflow volume generated during rainfalls with depths >15 mm. Tracing studies should be conducted to test the hypothesis of the stemflow contribution to aquifer recharge in temperate forests of northeastern Mexico.

Local variations in bone mineral density: a comparison of OCT versus x-ray micro-CT

NASA Astrophysics Data System (ADS)

Ugryumova, Nadya; Stevens-Smith, Jenna; Scutt, Andrew; Matcher, Stephen J.

2008-02-01

We describe variations in the degree of mineralisation within the subchondral bone plate of the equine metacarpophalangeal joint. A comparison of Optical Coherence Tomography, Micro CT, and SEM techniques was performed. These data are compared between sites on a healthy sample and at points on an osteoarthritically degenerated sample. No significant correlation was found between the optical scattering coefficient and the micro-CT derived BMD for comparisons between different sites on the bone surface. Also OCT demonstrated a larger regional variation in scattering coefficient than did micro CT for bone mineral density. This suggests that the optical scattering coefficient of bone is not related solely to the volume-density of calcium-phosphate. Patches of lower optical scattering coefficient were found in the bone structure that was related to the osteoarthritic lesion area on the overlying cartilage. Areas of microcracking, as revealed by both SEM and micro CT produced distinctive granularity in the OCT images. In further experiments, OCT was compared with micro CT and mechanical strength testing (3-point bending) in a small animal model of cardiovascular disease (cholesterol overload in mice). In the cardiovascular diseased mice, micro-CT of the trabecular bone did not demonstrate a significant change in trabecular bone mineral density before and after administration of the high cholesterol diet. However mechanical testing demonstrated a decrease in mechanical strength and OCT demonstrated a corresponding statistically significant decrease in optical scattering of the bone.

The seasonal use of small-scale space by benthic species in a transiently hypoxic area

NASA Astrophysics Data System (ADS)

Doya, Carolina; Aguzzi, Jacopo; Chatzievangelou, Damianos; Costa, Corrado; Company, Joan Baptista; Tunnicliffe, Verena

2016-02-01

The use of small-scale space by benthos and its variation over the seasons in transiently hypoxic zones is poorly known. In this study, we examined the reciprocal spatial dispersion of the squat lobster (Munida quadrispina) and the slender sole (Lyopsetta exilis) according to oxygen concentrations at a VENUS platform of Ocean Networks Canada (ONC). This platform is located in a seasonally hypoxic zone at 96 m depth in the fjord of Saanich Inlet (British Columbia, Canada). We counted and located small as well as large squat lobsters and slender soles in digital still images during 1 year (2012-2013) also concomitantly obtained oxygen data. Images were subdivided in a squared grid to obtain relative density maps as a proxy for surface occupation and spatial autocorrelation. Pearson's chi-squared tests at a yearly scale, along with Dixon's spatial segregation index (S) for each possible pair among the studied groups, showed a significant absence of overlap. The same analyses by month and cross-correlation between oxygen and S showed that while the dispersion patterns of the large squat lobsters seemed to be driven mainly by the morphology of the seafloor, an effect of hypoxia was found in the small squat lobsters and the slender soles levels of aggregation. Small squat lobster sought seabed protrusions, such as sponges, to reach more oxygenated water. The slender sole's space occupation decreased significantly, being forced to retreat when the squat lobsters' abundance peaked as a result of what appeared to be a seasonal reproduction event in early summer. Our results contribute to the understanding of the ways in which oxygen levels modulate substrate use by benthic species in the framework of a global expansion of hypoxia in coastal and ocean areas.

Habitat size modulates the influence of heterogeneity on species richness patterns in a model zooplankton community.

PubMed

Schuler, Matthew S; Chase, Jonathan M; Knight, Tiffany M

2017-06-01

Habitat heterogeneity is a primary mechanism influencing species richness. Despite the general expectation that increased heterogeneity should increase species richness, there is considerable variation in the observed relationship, including many studies that show negative effects of heterogeneity on species richness. One mechanism that can create such disparate results is the predicted trade-off between habitat area and heterogeneity, sometimes called the area-heterogeneity-trade-off (AHTO) hypothesis. The AHTO hypothesis predicts positive effects of heterogeneity on species richness in large habitats, but negative effects in small habitats. We examined the interplay between habitat size and habitat heterogeneity in experimental mesocosms that mimic freshwater ponds, and measured responses in a species-rich zooplankton community. We used the AHTO hypothesis and related mechanisms to make predictions about how heterogeneity would affect species richness and diversity in large compared to small habitats. We found that heterogeneity had a positive influence on species richness in large, but not small habitats, and that this likely resulted because habitat specialists were able to persist only when habitat size was sufficiently large, consistent with the predictions of the AHTO hypothesis. Our results emphasize the importance of considering context (e.g., habitat size in this case) when investigating the relative importance of ecological drivers of diversity, like heterogeneity. © 2017 by the Ecological Society of America.

Multi-scale structures and pasting characteristics of starch in whole-wheat flour treated by superfine grinding.

PubMed

Niu, Meng; Zhang, Binjia; Jia, Caihua; Zhao, Siming

2017-11-01

The multi-scale structures and pasting properties of starch in WWF were investigated after superfine grinding. Five particle size distributions of WWF and their corresponding starch were obtained. The grinding process reduced the particle size of WWF and starch. However, a slight increase of fragments from starch granules was observed with enhanced grinding strength because of the small decrease in starch particle size and the existence of other WWF components that undertook some of shearing force and friction during grinding. A prominent reduction in starch crystallinity was resulted due to the destruction of crystalline structure by grinding. Small-angle X-ray scattering analyses indicated the disordering in starch semi-crystalline lamellae with thinner lamellae thickness. Additionally, the 13 C Nuclear Magnetic Resonance spectra demonstrated the alterations in starch chain conformation by varying peak areas of starch carbons (C1 and C4). Along with these structural changes, Starch pasting characteristics showed substantial variations, indicating decreased viscosities and higher pasting stability. The results suggest that the grinding treatments influenced the structures and pasting properties of starch even at a non-separated state, the changes in starch structures were related to the variations in starch gelatinization characteristics. Copyright © 2017 Elsevier B.V. All rights reserved.

An investigation into the utilization of HCMM thermal data for the descrimination of volcanic and Eolian geological units. [Craters of the Moon volcanic field, Idaho; San Francisco volcanic field, Arizona; High Desert, California; and the Cascade Range, California and Oregon

NASA Technical Reports Server (NTRS)

Head, J. W., III (Principal Investigator)

1982-01-01

Analysis of HCMM data shows that the resolution provided by the thermal data is inadequate to permit the identification of individual lava flows within the volcanic test sites. Thermal data of southern California reveals that dune complexes at Kelso and Algodomes are found to be too small to permit adequate investigation of their structure. As part of the study of the San Francisco volcanic field, marked variations in the thermal properties of the region between Flagstaff and the Utah State border were observed. Several well-defined units within the Grand Canyon and the Colorado Plateau were recognized and appear to be very suitable for analysis with HCMM, SEASAT and LANDSAT images. Although individual volcanic constructs within the Cascade Range are too small to permit detailed characterization with the thermal data, the regional volcano/tectonic setting offers a good opportunity for comparing the possible thermal distinction between this area and sedimentary fold belts such as those found in the eastern United States. Strong intra-regional variations in vegetation cover were also tentatively identified for the Oregon test site.

Interaction networks and the use of floral resources by male orchid bees (Hymenoptera: Apidae: Euglossini) in a primary rain forests of the Chocó Region (Colombia).

PubMed

Ospina-Torres, Rodulfo; Montoya-Pfeiffer, Paula María; Parra-H, Alejandro; Solarte, Victor; Tupac Otero, Joel

2015-09-01

Orchid bees are important keystone pollinators from the Neotropics. With the aim to study the relationships between orchid bees and their nectar and aromatic host species, we made systematic samplings of males across two conservation areas in the biogeographic Choc6 Region of Colombia. We used chemical baits to collect 352 male bees during five months. The pollen attached to their bodies was extracted for palynological identification and to estimate interaction networks. The euglossine community consisted of at least 22 species including Eg. maculilabris, Eg. orellana, Eg. championi and Eg. ignita. The male bees were associated with 84 plants but depended on a small group of them (Peperomia spp. and Anthurium spp, as well as species of Solanaceae, Ericaceae and Malpighiaceae) which were widely distributed across the altitudinal gradient, and were available through the year. The resulting interaction networks revealed a typical nested pattern usually found in plant-pollinator interactions, with several rare bee and plant species interaction with a small group of generalist bees and plant species. Albeit, we found variation within networks related to species composition. Such variation may be a consequence of specific differences in plant flowering phenology.

Meteorology-induced variations in the spatial behavior of summer ozone pollution in Central California

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

Jin, Ling; Harley, Robert A.; Brown, Nancy J.

Cluster analysis was applied to daily 8 h ozone maxima modeled for a summer season to characterize meteorology-induced variations in the spatial distribution of ozone. Principal component analysis is employed to form a reduced dimension set to describe and interpret ozone spatial patterns. The first three principal components (PCs) capture {approx}85% of total variance, with PC1 describing a general spatial trend, and PC2 and PC3 each describing a spatial contrast. Six clusters were identified for California's San Joaquin Valley (SJV) with two low, three moderate, and one high-ozone cluster. The moderate ozone clusters are distinguished by elevated ozone levels inmore » different parts of the valley: northern, western, and eastern, respectively. The SJV ozone clusters have stronger coupling with the San Francisco Bay area (SFB) than with the Sacramento Valley (SV). Variations in ozone spatial distributions induced by anthropogenic emission changes are small relative to the overall variations in ozone amomalies observed for the whole summer. Ozone regimes identified here are mostly determined by the direct and indirect meteorological effects. Existing measurement sites are sufficiently representative to capture ozone spatial patterns in the SFB and SV, but the western side of the SJV is under-sampled.« less

Multi-isotope tracers to investigate processes in the Elbe, Weser and Ems river catchment using B, Mo, Sr, and Pb isotope ratios assessed by MC ICP-MS

NASA Astrophysics Data System (ADS)

Irrgeher, Johanna; Reese, Anna; Zimmermann, Tristan; Prohaska, Thomas; Retzmann, Anika; Wieser, Michael E.; Zitek, Andreas; Proefrock, Daniel

2017-04-01

Environmental monitoring of complex ecosystems requires reliable sensitive techniques based on sound analytical strategies to identify the source, fate and sink of elements and matter. Isotopic signatures can serve to trace pathways by making use of specific isotopic fingermarks or to distinguish between natural and anthropogenic sources. The presented work shows the potential of using the isotopic variation of Sr, Pb (as well-established isotopic systems), Mo and B (as novel isotopic system) assessed by MC ICP-MS in water and sediment samples to study aquatic ecosystem transport processes. The isotopic variation of Sr, Pb, Mo and B was determined in different marine and estuarine compartments covering the catchment of the German Wadden Sea and its main tributaries, the Elbe, Weser and Ems River. The varying elemental concentrations, the complex matrix and the expected small variations in the isotopic composition required the development and application of reliable analytical measurement approaches as well as suited metrological data evaluation strategies. Aquatic isoscapes were created using ArcGIS® by relating spatial isotopic data with geographical and geological maps. The elemental and isotopic distribution maps show large variation for different parameters and also reflect the numerous impact factors (e.g. geology, anthropogenic sources) influencing the catchment area.

Prey-mediated avoidance of an intraguild predator by its intraguild prey

USGS Publications Warehouse

Wilson, R.R.; Blankenship, T.L.; Hooten, M.B.; Shivik, J.A.

2010-01-01

Intraguild (IG) predation is an important factor influencing community structure, yet factors allowing coexistence of IG predator and IG prey are not well understood. The existence of spatial refuges for IG prey has recently been noted for their importance in allowing coexistence. However, reduction in basal prey availability might lead IG prey to leave spatial refuges for greater access to prey, leading to increased IG predation and fewer opportunities for coexistence. We determined how the availability of prey affected space-use patterns of bobcats (Lynx rufus, IG prey) in relation to coyote space-use patterns (Canis latrans, IG predators). We located animals from fall 2007 to spring 2009 and estimated bobcat home ranges and core areas seasonally. For each bobcat relocation, we determined intensity of coyote use, distance to water, small mammal biomass, and mean small mammal biomass of the home range during the season the location was collected. We built generalized linear mixed models and used Akaike Information Criteria to determine which factors best predicted bobcat space use. Coyote intensity was a primary determinant of bobcat core area location. In bobcat home ranges with abundant prey, core areas occurred where coyote use was low, but shifted to areas intensively used by coyotes when prey declined. High spatial variability in basal prey abundance allowed some bobcats to avoid coyotes while at the same time others were forced into more risky areas. Our results suggest that multiple behavioral strategies associated with spatial variation in basal prey abundance likely allow IG prey and IG predators to coexist. ?? 2010 Springer-Verlag.

Geographic variation in migration chronology and winter distribution of midcontinent greater white-fronted geese

USGS Publications Warehouse

Ely, Craig R.; Nieman, Daniel J.; Alisauskas, Ray T.; Schmutz, Joel A.; Hines, James E.

2013-01-01

We evaluated spatial and temporal differences in migratory behavior among different breeding groups of midcontinent greater white-fronted geese (Anser albifrons) using band-recovery data and observations of neck collared geese during migration and winter. Birds from different breeding areas were initially delineated by geographic distance into 6 banding reference areas (BRAs): 1) interior Alaska, 2) North Slope of Alaska, 3) western Northwest Territories (NWT), 4) western Nunavut, 5) central Nunavut, and 6) eastern Nunavut. The banding groups also differed by breeding habitat, with geese from interior Alaska nesting in the boreal forest (taiga), and all other groups breeding in tundra habitats. Geese from interior Alaska migrated earlier during autumn, and were more likely to winter farther south (in Mexico) than geese from other breeding areas. Geese banded in central and eastern Nunavut (Queen Maud Gulf and Inglis River) wintered farther east (in Louisiana) than geese from other breeding areas. Small-scale (within-state) geographic segregation of wintering flocks was evidenced by the recent (post-1990) nearly exclusive use of a new wintering area in north central Texas by geese from interior Alaska. Segregation among BRAs was also apparent in Mexico, where taiga geese were found predominantly in the central Highlands (states of Zacatecas and Durango), whereas tundra geese mostly used states along the Gulf Coast (primarily Tamaulipas). Interior Alaska birds initiated spring migration earlier than geese from other areas, and were more likely than others to stop in the Rainwater Basin of Nebraska, a region where cholera outbreaks periodically kill thousands of geese. Geese from interior Alaska were the first to arrive at spring staging areas in prairie Canada where BRAs exhibited spatial delineation (a longitudinal cline) in relation to breeding areas. Our results show significant geographic and temporal variation among taiga and tundra breeding cohorts during autumn, winter, and spring. Temporal and spatial differences in migratory behavior may allow management practices that accommodate potential demographic differences between taiga and tundra populations.

Impacts of Wildfires on Land Surface Phenology of Western US Forests

NASA Astrophysics Data System (ADS)

Wang, J.; Zhang, X.

2017-12-01

Land surface phenology (LSP) characterizes seasonal dynamics of vegetation communities within a satellite pixel. The temporal variation of LSP has been widely associated with recent global climate change. However, few studies have focused on the influence of land disturbance, such as wildfire, on LSP variations, which is particularly true at a continental scale. Wildfire has increased in size and severity in the western United States (US) during last few decades. To explore wildfire impacts on LSP in the western US forest, we analyzed the start of growing season (SOS) integrated from the entire forest area, the burned area, and the unburned area, respectively. Specifically, SOS was derived from time series of daily MODIS surface reflectance product at 250 m using a hybrid piecewise logistic detection model. The annual burn perimeters during 2000-2014 were obtained from Monitoring Trends in Burn Severity maps to study the wildfire effect on the SOS in the subsequent years (2001-2015). The wildfire effect was analyzed at three levels: the entire western US, Environmental Protection Agency's Level III ecoregions, and states. Results show that wildfires basically advance SOS but have diverse effects with different regions and years. Comparing SOS in the burned areas with that in surrounding unburned areas from 2001-2015, it was found that the SOS shift was -3.4 days (-: earlier; +: later) on average in the western US forests, and varied from -16.1 to 13.1 days across ecoregions and from -11.4 to 4.3 days across states. Because of the small proportion of annual burned areas (<0.7%) over the entire region, the SOS shift in the burned areas had limited influences on the overall SOS, which caused shifts of -0.06 days over the entire western US, from -0.2 to 0.2 days across ecoregions, and -0.06 to 0.13 days across states. Overall, this study demonstrates that wildfires strongly impact SOS at local areas although the effect in the large region is relatively limited.

Compounding nonlinearities in the climate and wildfire system contribute to high uncertainty in estimates of future burned area in the western United State

NASA Astrophysics Data System (ADS)

Williams, P.

2015-12-01

Ecological studies are increasingly recognizing the importance of atmospheric vapor-pressure deficit (VPD) as a driver of forest drought stress and disturbance processes such as wildfire. Because of the nonlinear Clausius-Clapeyron relationship between temperature and saturation vapor pressure, small variations in temperature can have large impacts on VPD, and therefore drought, particularly in warm, dry areas and particularly during the warm season. It is also clear that VPD and drought affect forest fire nonlinearly, as incremental drying leads to increasingly large burned areas. Forest fire is also affected by fuel amount and connectivity, which are promoted by vegetation growth in previous years, which is in turn promoted by lack of drought, highlighting the importance of nuances in the sequencing of natural interannual climate variations in modulating the impacts of drought on wildfire. The many factors affecting forest fire, and the nonlinearities embedded within the climate and wildfire systems, cause interannual variability in forest-fire area and frequency to be wildly variable and strongly affected by internal climate variability. In addition, warming over the past century has produced a background increase in forest fire frequency and area in many regions. In this talk I focus on the western United States and will explore whether the relationships between internal climate variability on forest fire area have been amplified by the effects of warming as a result of the compounding nonlinearities described above. I will then explore what this means for future burned area in the western United States and make the case that uncertainties in the future global greenhouse gas emissions trajectory, model projections of mean temperatures, model projections of precipitation, and model projections of natural climate variability translate to very large uncertainties in the effects of future climate variability on forest fire area in the United States and globally.

Small-area estimation of the probability of toxocariasis in New York City based on sociodemographic neighborhood composition.

PubMed

Walsh, Michael G; Haseeb, M A

2014-01-01

Toxocariasis is increasingly recognized as an important neglected infection of poverty (NIP) in developed countries, and may constitute the most important NIP in the United States (US) given its association with chronic sequelae such as asthma and poor cognitive development. Its potential public health burden notwithstanding, toxocariasis surveillance is minimal throughout the US and so the true burden of disease remains uncertain in many areas. The Third National Health and Nutrition Examination Survey conducted a representative serologic survey of toxocariasis to estimate the prevalence of infection in diverse US subpopulations across different regions of the country. Using the NHANES III surveillance data, the current study applied the predicted probabilities of toxocariasis to the sociodemographic composition of New York census tracts to estimate the local probability of infection across the city. The predicted probability of toxocariasis ranged from 6% among US-born Latino women with a university education to 57% among immigrant men with less than a high school education. The predicted probability of toxocariasis exhibited marked spatial variation across the city, with particularly high infection probabilities in large sections of Queens, and smaller, more concentrated areas of Brooklyn and northern Manhattan. This investigation is the first attempt at small-area estimation of the probability surface of toxocariasis in a major US city. While this study does not define toxocariasis risk directly, it does provide a much needed tool to aid the development of toxocariasis surveillance in New York City.

Small-Area Estimation of the Probability of Toxocariasis in New York City Based on Sociodemographic Neighborhood Composition

PubMed Central

Walsh, Michael G.; Haseeb, M. A.

2014-01-01

Toxocariasis is increasingly recognized as an important neglected infection of poverty (NIP) in developed countries, and may constitute the most important NIP in the United States (US) given its association with chronic sequelae such as asthma and poor cognitive development. Its potential public health burden notwithstanding, toxocariasis surveillance is minimal throughout the US and so the true burden of disease remains uncertain in many areas. The Third National Health and Nutrition Examination Survey conducted a representative serologic survey of toxocariasis to estimate the prevalence of infection in diverse US subpopulations across different regions of the country. Using the NHANES III surveillance data, the current study applied the predicted probabilities of toxocariasis to the sociodemographic composition of New York census tracts to estimate the local probability of infection across the city. The predicted probability of toxocariasis ranged from 6% among US-born Latino women with a university education to 57% among immigrant men with less than a high school education. The predicted probability of toxocariasis exhibited marked spatial variation across the city, with particularly high infection probabilities in large sections of Queens, and smaller, more concentrated areas of Brooklyn and northern Manhattan. This investigation is the first attempt at small-area estimation of the probability surface of toxocariasis in a major US city. While this study does not define toxocariasis risk directly, it does provide a much needed tool to aid the development of toxocariasis surveillance in New York City. PMID:24918785

Managed care market share and cesarean section rates in the United States: is there a link?

PubMed

Hueston, W J; Sutton, A

2000-11-01

After peaking during the early 1980s, cesarean section rates in the United States have been falling for the last decade. At the same time, managed care enrollment has increased dramatically. This study examines whether managed care penetration in local markets is associated with lower cesarean section rates in those geographic area. A cross-sectional comparison of cesarean section rates and health maintenance organization (HMO) market penetration in 61 selected metropolitan areas in the United States was conducted. National birth certificate data for 1996 were used to calculate crude and race-adjusted cesarean section rates for residents in each area. No relationship between overall cesarean section rates in the metropolitan areas and managed care penetration was observed. Subanalyses of racial groups demonstrated the existence of a weak association between managed care penetration and cesarean section rates for white women (21.2% for the highest quartile of HMO penetration, compared with 19.1% for the lowest quartile; P = .03), but not for African-Americans or other minorities. Managed care penetration in a market may have an association with cesarean section rates for white women, but the strength of this relationship is small. Even if managed care delivery systems reduce cesarean section rates in their own populations, this change is likely to have only a small impact on overall cesarean rates. HMO penetration is unlikely to influence national cesarean section rates, nor does it appear to explain state variations in these rates.

Meta-Analysis of Mitochondrial DNA Variation in the Iberian Peninsula.

PubMed

Barral-Arca, Ruth; Pischedda, Sara; Gómez-Carballa, Alberto; Pastoriza, Ana; Mosquera-Miguel, Ana; López-Soto, Manuel; Martinón-Torres, Federico; Álvarez-Iglesias, Vanesa; Salas, Antonio

2016-01-01

The Iberian Peninsula has been the focus of attention of numerous studies dealing with mitochondrial DNA (mtDNA) variation, most of them targeting the control region segment. In the present study we sequenced the control region of 3,024 Spanish individuals from areas where available data were still limited. We also compiled mtDNA haplotypes from the literature involving 4,588 sequences and 28 population groups or small regions. We meta-analyzed all these data in order to shed further light on patterns of geographic variation, taking advantage of the large sample size and geographic coverage, in contrast with the atomized sampling strategy of previous work. The results indicate that the main mtDNA haplogroups show primarily clinal geographic patterns across the Iberian geography, roughly along a North-South axis. Haplogroup HV0 (where haplogroup U is nested) is more prevalent in the Franco Cantabrian region, in good agreement with previous findings that identified this area as a climate refuge during the Last Glacial Maximum (LGM), prior to a subsequent demographic re-expansion towards Central Europe and the Mediterranean. Typical sub-Saharan and North African lineages are slightly more prevalent in South Iberia, although at low frequencies; this pattern has been shaped mainly by the transatlantic slave trade and the Arab invasion of the Iberian Peninsula. The results also indicate that summary statistics that aim to measure molecular variation, or AMOVA, have limited sensitivity to detect population substructure, in contrast to patterns revealed by phylogeographic analysis. Overall, the results suggest that mtDNA variation in Iberia is substantially stratified. These patterns might be relevant in biomedical studies given that stratification is a common cause of false positives in case-control mtDNA association studies, and should be also considered when weighting the DNA evidence in forensic casework, which is strongly dependent on haplotype frequencies.

Geographic Variation in Maternal Smoking during Pregnancy in the Missouri Adolescent Female Twin Study (MOAFTS)

PubMed Central

Lian, Min; Madden, Pamela A.; Lynskey, Michael T.; Colditz, Graham A.; Lessov-Schlaggar, Christina N.; Schootman, Mario; Heath, Andrew C.

2016-01-01

Objective Despite well-known adverse health effects of maternal smoking during pregnancy (MSP), it is still unclear if MSP varies geographically and if neighborhood socioeconomic deprivation (SED) plays an important role in MSP. This study aims to investigate small-area geographic variation in MSP and examine the association of SED with MSP. Methods The Missouri Adolescent Female Twin Study (MOAFTS) is a cohort study of female like-sex twins born in Missouri to Missouri-resident parents during 1975–1985. Biological mothers completed a baseline interview in 1995–1998 and reported MSP with the twins. Residential address of the mother at birth was geocoded. We developed a census tract-level SED index using a common factor approach based on 21 area-level socioeconomic variables from the 1980 Census data. Multilevel logistic regressions estimated geographic heterogeneity (random effect) in MSP and the odds ratios (ORs, fixed effects) of neighborhood SED associated with MSP. Results Of 1658 MOAFTS mothers, 35.2% reported any MSP and 21.9% reported MSP beyond the first trimester. Neighborhood SED was associated with any MSP (the highest vs. the lowest quartile: OR = 1.90, 95% confidence interval [CI] = 1.40–2.57, Ptrend<0.001) and MSP beyond the first trimester (OR = 1.98, 95% CI = 1.38–2.85, Ptrend = 0.002) in unadjusted analyses. After adjusting for individual covariates (demographics, socioeconomic conditions, alcohol use, and parents’ cohabitation), neighborhood SED was not associated with MSP, but geographic variation still persisted in MSP (variance = 0.41, P = 0.003) and in MSP beyond the first trimester (variance = 0.82, P<0.001). Conclusions Neighborhood SED was associated with MSP in unadjusted analyses but this association could be explained by individual socioeconomic conditions. Nonetheless, significant geographic variation in MSP persisted and was not accounted for by differences in neighborhood SED. To develop effective interventions to reduce MSP, further studies are necessary to explore underlying reasons for its geographic variation. PMID:27100091

Indian Ocean analyses

NASA Technical Reports Server (NTRS)

Meyers, Gary

1992-01-01

The background and goals of Indian Ocean thermal sampling are discussed from the perspective of a national project which has research goals relevant to variation of climate in Australia. The critical areas of SST variation are identified. The first goal of thermal sampling at this stage is to develop a climatology of thermal structure in the areas and a description of the annual variation of major currents. The sampling strategy is reviewed. Dense XBT sampling is required to achieve accurate, monthly maps of isotherm-depth because of the high level of noise in the measurements caused by aliasing of small scale variation. In the Indian Ocean ship routes dictate where adequate sampling can be achieved. An efficient sampling rate on available routes is determined based on objective analysis. The statistical structure required for objective analysis is described and compared at 95 locations in the tropical Pacific and 107 in the tropical Indian Oceans. XBT data management and quality control methods at CSIRO are reviewed. Results on the mean and annual variation of temperature and baroclinic structure in the South Equatorial Current and Pacific/Indian Ocean Throughflow are presented for the region between northwest Australia and Java-Timor. The mean relative geostrophic transport (0/400 db) of Throughflow is approximately 5 x 106 m3/sec. A nearly equal volume transport is associated with the reference velocity at 400 db. The Throughflow feeds the South Equatorial Current, which has maximum westward flow in August/September, at the end of the southeasterly Monsoon season. A strong semiannual oscillation in the South Java Current is documented. The results are in good agreement with the Semtner and Chervin (1988) ocean general circulation model. The talk concludes with comments on data inadequacies (insufficient coverage, timeliness) particular to the Indian Ocean and suggestions on the future role that can be played by Data Centers, particularly with regard to quality control of data as research bodies are replaced by operational bodies in the Global Ocean Observing System.

Meta-Analysis of Mitochondrial DNA Variation in the Iberian Peninsula

PubMed Central

Barral-Arca, Ruth; Pischedda, Sara; Gómez-Carballa, Alberto; Pastoriza, Ana; Mosquera-Miguel, Ana; López-Soto, Manuel; Martinón-Torres, Federico; Álvarez-Iglesias, Vanesa; Salas, Antonio

2016-01-01

The Iberian Peninsula has been the focus of attention of numerous studies dealing with mitochondrial DNA (mtDNA) variation, most of them targeting the control region segment. In the present study we sequenced the control region of 3,024 Spanish individuals from areas where available data were still limited. We also compiled mtDNA haplotypes from the literature involving 4,588 sequences and 28 population groups or small regions. We meta-analyzed all these data in order to shed further light on patterns of geographic variation, taking advantage of the large sample size and geographic coverage, in contrast with the atomized sampling strategy of previous work. The results indicate that the main mtDNA haplogroups show primarily clinal geographic patterns across the Iberian geography, roughly along a North-South axis. Haplogroup HV0 (where haplogroup U is nested) is more prevalent in the Franco Cantabrian region, in good agreement with previous findings that identified this area as a climate refuge during the Last Glacial Maximum (LGM), prior to a subsequent demographic re-expansion towards Central Europe and the Mediterranean. Typical sub-Saharan and North African lineages are slightly more prevalent in South Iberia, although at low frequencies; this pattern has been shaped mainly by the transatlantic slave trade and the Arab invasion of the Iberian Peninsula. The results also indicate that summary statistics that aim to measure molecular variation, or AMOVA, have limited sensitivity to detect population substructure, in contrast to patterns revealed by phylogeographic analysis. Overall, the results suggest that mtDNA variation in Iberia is substantially stratified. These patterns might be relevant in biomedical studies given that stratification is a common cause of false positives in case-control mtDNA association studies, and should be also considered when weighting the DNA evidence in forensic casework, which is strongly dependent on haplotype frequencies. PMID:27441366

Automatic devices to take water samples and to raise trash screens at weirs

Treesearch

K. G. Reinhart; R. E. Leonard; G. E. Hart

1960-01-01

Experimentation on small watersheds is assuming increasing importance in watershed-management research. Much has been accomplished in developing adequate instrumentation for use in these experiments. Yet many problems still await solution. One difficulty encountered is that small streams are subject to wide variations in flow and that these variations are generally...

Detection of retinal capillary nonperfusion in fundus fluorescein angiogram of diabetic retinopathy.

PubMed

Rasta, Seyed Hossein; Nikfarjam, Shima; Javadzadeh, Alireza

2015-01-01

Retinal capillary nonperfusion (CNP) is one of the retinal vascular diseases in diabetic retinopathy (DR) patients. As there is no comprehensive detection technique to recognize CNP areas, we proposed a different method for computing detection of ischemic retina, non-perfused (NP) regions, in fundus fluorescein angiogram (FFA) images. Whilst major vessels appear as ridges, non-perfused areas are usually observed as ponds that are surrounded by healthy capillaries in FFA images. A new technique using homomorphic filtering to correct light illumination and detect the ponds surrounded in healthy capillaries on FFA images was designed and applied on DR fundus images. These images were acquired from the diabetic patients who had referred to the Nikookari hospital and were diagnosed for diabetic retinopathy during one year. Our strategy was screening the whole image with a fixed window size, which is small enough to enclose areas with identified topographic characteristics. To discard false nominees, we also performed a thresholding operation on the screen and marked images. To validate its performance we applied our detection algorithm on 41 FFA diabetic retinopathy fundus images in which the CNP areas were manually delineated by three clinical experts. Lesions were found as smooth regions with very high uniformity, low entropy, and small intensity variations in FFA images. The results of automated detection method were compared with manually marked CNP areas so achieved sensitivity of 81%, specificity of 78%, and accuracy of 91%.The result was present as a Receiver operating character (ROC) curve, which has an area under the curve (AUC) of 0.796 with 95% confidence intervals. This technique introduced a new automated detection algorithm to recognize non-perfusion lesions on FFA. This has potential to assist detecting and managing of ischemic retina and may be incorporated into automated grading diabetic retinopathy structures.

Habitat use by Swainson's Warblers in a managed bottomland forest

USGS Publications Warehouse

Somershoe, S.G.; Hudman, S.P.; Chandler, C.R.

2003-01-01

The Swainson's Warbler (Limnothlypis swainsonii) is a locally distributed and relatively uncommon Neotropical migrant songbird that breeds in the bottomland forests of the southeastern United States and spends the nonbreeding season in the Caribbean Basin. Populations of Swainson's Warblers have declined during recent decades as bottomland forests have come under increasingly intensive management and large areas have been converted to other land uses. We examined the habitat around song perches used by male Swainson's Warblers at Big Hammock Wildlife Management Area, a managed bottomland forest along the Altamaha River in Tattnall County, Georgia. We quantified 20 features of habitat structure in areas occupied by Swainson's Warblers (occupied plots) and two sets of controls: unoccupied plots adjacent to occupied plots (adjacent control plots) and unoccupied plots throughout the management area (general control plots). Occupied plots and adjacent control plots both differed in structure from the general control plots. We detected no significant differences, however, in vegetation structure between occupied plots and adjacent control plots. General control plots tended to have a greater number of trees, greater basal area, and a complete canopy, whereas occupied and adjacent control plots had high densities of small stems, cane, herbaceous ground cover, and leaf litter; this latter pattern is typical of documented Swainson's Warbler breeding habitat. Lack of significant differences in vegetation structure may be due to great variation in habitat structure around song perches, small sample size, or scarcity of Swainson's Warblers. Future research should focus on quantifying habitat characteristics around nest sites, song perches, and feeding areas. Our results suggest that management of bottomland habitats by thinning forests and encouraging regeneration of canebrakes is needed for successful conservation of Swainson's Warblers.

Land-use controls on sources and processing of nitrate in small watersheds: Insights from dual isotopic analysis

USGS Publications Warehouse

Barnes, R.T.; Raymond, P.A.

2010-01-01

Studies have repeatedly shown that agricultural and urban areas export considerably more nitrogen to streams than forested counterparts, yet it is difficult to identify and quantify nitrogen sources to streams due to complications associated with terrestrial and in-stream biogeochemical processes. In this study, we used the isotopic composition of nitrate (??15N-NO3- and ??18O- NO3-) in conjunction with a simple numerical model to examine the spatial and temporal variability of nitrate (NO3-) export across a land-use gradient and how agricultural and urban development affects net removal mechanisms. In an effort to isolate the effects of land use, we chose small headwater systems in close proximity to each other, limiting the variation in geology, surficial materials, and climate between sites. The ??15N and ??18Oof stream NO 3- varied significantly between urban, agricultural, and forested watersheds, indicating that nitrogen sources are the primary determinant of the ??15N-NO3-, while the ??18O-NO3- was found to reflect biogeochemical processes. The greatest NO3- concentrations corresponded with the highest stream ??15N-NO3- values due to the enriched nature of two dominant anthropogenic sources, septic and manure, within the urban and agricultural watersheds, respectively. On average, net removal of the available NO3- pool within urban and agricultural catchments was estimated at 45%. The variation in the estimated net removal of NO3- from developed watersheds was related to both drainage area and the availability of organic carbon. The determination of differentiated isotopic land-use signatures and dominant seasonal mechanisms illustrates the usefulness of this approach in examining the sources and processing of excess nitrogen within headwater catchments. ?? 2010 by the Ecological Society of America.

Reliable detection of fluence anomalies in EPID-based IMRT pretreatment quality assurance using pixel intensity deviations

PubMed Central

Gordon, J. J.; Gardner, J. K.; Wang, S.; Siebers, J. V.

2012-01-01

Purpose: This work uses repeat images of intensity modulated radiation therapy (IMRT) fields to quantify fluence anomalies (i.e., delivery errors) that can be reliably detected in electronic portal images used for IMRT pretreatment quality assurance. Methods: Repeat images of 11 clinical IMRT fields are acquired on a Varian Trilogy linear accelerator at energies of 6 MV and 18 MV. Acquired images are corrected for output variations and registered to minimize the impact of linear accelerator and electronic portal imaging device (EPID) positioning deviations. Detection studies are performed in which rectangular anomalies of various sizes are inserted into the images. The performance of detection strategies based on pixel intensity deviations (PIDs) and gamma indices is evaluated using receiver operating characteristic analysis. Results: Residual differences between registered images are due to interfraction positional deviations of jaws and multileaf collimator leaves, plus imager noise. Positional deviations produce large intensity differences that degrade anomaly detection. Gradient effects are suppressed in PIDs using gradient scaling. Background noise is suppressed using median filtering. In the majority of images, PID-based detection strategies can reliably detect fluence anomalies of ≥5% in ∼1 mm2 areas and ≥2% in ∼20 mm2 areas. Conclusions: The ability to detect small dose differences (≤2%) depends strongly on the level of background noise. This in turn depends on the accuracy of image registration, the quality of the reference image, and field properties. The longer term aim of this work is to develop accurate and reliable methods of detecting IMRT delivery errors and variations. The ability to resolve small anomalies will allow the accuracy of advanced treatment techniques, such as image guided, adaptive, and arc therapies, to be quantified. PMID:22894421

[Spatial variation characteristics of surface soil water content, bulk density and saturated hydraulic conductivity on Karst slopes].

PubMed

Zhang, Chuan; Chen, Hong-Song; Zhang, Wei; Nie, Yun-Peng; Ye, Ying-Ying; Wang, Ke-Lin

2014-06-01

Surface soil water-physical properties play a decisive role in the dynamics of deep soil water. Knowledge of their spatial variation is helpful in understanding the processes of rainfall infiltration and runoff generation, which will contribute to the reasonable utilization of soil water resources in mountainous areas. Based on a grid sampling scheme (10 m x 10 m) and geostatistical methods, this paper aimed to study the spatial variability of surface (0-10 cm) soil water content, soil bulk density and saturated hydraulic conductivity on a typical shrub slope (90 m x 120 m, projected length) in Karst area of northwest Guangxi, southwest China. The results showed that the surface soil water content, bulk density and saturated hydraulic conductivity had different spatial dependence and spatial structure. Sample variogram of the soil water content was fitted well by Gaussian models with the nugget effect, while soil bulk density and saturated hydraulic conductivity were fitted well by exponential models with the nugget effect. Variability of soil water content showed strong spatial dependence, while the soil bulk density and saturated hydraulic conductivity showed moderate spatial dependence. The spatial ranges of the soil water content and saturated hydraulic conductivity were small, while that of the soil bulk density was much bigger. In general, the soil water content increased with the increase of altitude while it was opposite for the soil bulk densi- ty. However, the soil saturated hydraulic conductivity had a random distribution of large amounts of small patches, showing high spatial heterogeneity. Soil water content negatively (P < 0.01) correlated with the bulk density and saturated hydraulic conductivity, while there was no significant correlation between the soil bulk density and saturated hydraulic conductivity.

Chemical and isotopic fingerprinting of small ungauged watershed: How far the hydrological functioning can be understood?

NASA Astrophysics Data System (ADS)

Petelet-Giraud, Emmanuelle; Luck, Jean-Marc; Ben Othman, Dalila; Joseph, Christian; Négrel, Philippe

2016-05-01

This study presents the ability of major/trace elements together with strontium isotopes to trace water origins at small scale at the outlet of a small watershed (Peyne, Hérault, France). Two small sub-basins draining distinct lithologies in their headwater (Plio-Villafranchian conglomerate versus Triassic gypsum-rich marls and dolomites) and the Miocene formations downstream are investigated. The Ca/Na vs. Mg/Na ratios and Ca/Sr vs. 87Sr/86Sr ratios allow the different facies that imprint the water signature to be identified, according to the hydrological conditions (low/high flows). Moreover, Sr isotopes evidence the two distinct Miocene facies, the sandy marls and the marine carbonates. The variation of the signature at the outlet of the basin allows identifying the main contributing compartments according to the hydrological conditions. This approach, based on a limited number of samples, highlights the potential of geochemical and isotopic tracers to define the contributing compartments to the runoff at the outlet of a basin. It thus could be considered as a potential alternative way to classical hydrological monitoring to delineate the main contributing areas during floods, especially in small ungauged river basins, where most of the devastating flash floods are recorded.

Use of routinely collected data on trihalomethane in drinking water for epidemiological purposes

PubMed Central

Keegan, T; Whitaker, H; Nieuwenhuijsen, M; Toledano, M; Elliott, P; Fawell, J; Wilkinson, M; Best, N

2001-01-01

OBJECTIVES—To explore the use of routinely collected trihalomethane (THM) measurements for epidemiological studies. Recently there has been interest in the relation between byproducts of disinfection of public drinking water and certain adverse reproductive outcomes, including stillbirth, congenital malformations, and low birth weight.
METHOD—Five years of THM readings (1992-6), collected for compliance with statutory limits, were analysed. One water company in the north west of England, divided into 288 water zones, provided 15 984 observations for statistical analysis. On average each zone was sampled 11.1 times a year. Five year, annual, monthly, and seasonal variation in THMs were examined as well as the variability within and between zones.
RESULTS—Between 1992 and 1996 the total THM (TTHM) annual zone means were less than half the statutory concentration, at approximately 46 µg/l. Differences in annual water zone means were within 7%. Over the study period, the maximum water zone mean fell from 142.2 to 88.1 µg/l. Mean annual concentrations for individual THMs (µg/l) were 36.6, 8.0, and 2.8 for chloroform, bromodichloromethane (BDCM), and dibromochloromethane (DBCM) respectively. Bromoform data were not analysed, because a high proportion of the data were below the detection limit. The correlation between chloroform and TTHM was 0.98, between BDCM and TTHM 0.62, and between DBCM and TTHM −0.09. Between zone variation was larger than within zone variation for chloroform and BDCM, but not for DBCM. There was only little seasonal variation (<3%). Monthly variation was found although there were no consistent trends within years.
CONCLUSION—In an area where the TTHM concentrations were less than half the statutory limit (48 µg/l) chloroform formed a high proportion of TTHM. The results of the correlation analysis suggest that TTHM concentrations provided a good indication of chloroform concentrations, a reasonable indication of BDCM concentrations, but no indication of DBCM. Zone means were similar over the years, but the maximum concentrations reduced considerably, which suggests that successful improvements in treatment have been made to reduce high TTHM concentrations in the area. For chloroform and BDCM, the main THMs, the component between water zones was greater than variation within water zones and explained most of the overall exposure variation. Variation between months and seasons was low and showed no clear trends within years. The results indicate that routinely collected data can be used to obtain exposure estimates for epidemiological studies at a small area level.


Keywords: chlorination byproducts; exposure; birth outcomes; routine data; trihalomethanes PMID:11404449

Biosafety research for non-target organism risk assessment of RNAi-based GE plants

PubMed Central

Roberts, Andrew F.; Devos, Yann; Lemgo, Godwin N. Y.; Zhou, Xuguo

2015-01-01

RNA interference, or RNAi, refers to a set of biological processes that make use of conserved cellular machinery to silence genes. Although there are several variations in the source and mechanism, they are all triggered by double stranded RNA (dsRNA) which is processed by a protein complex into small, single stranded RNA, referred to as small interfering RNAs (siRNA) with complementarity to sequences in genes targeted for silencing. The use of the RNAi mechanism to develop new traits in plants has fueled a discussion about the environmental safety of the technology for these applications, and this was the subject of a symposium session at the 13th ISBGMO in Cape Town, South Africa. This paper continues that discussion by proposing research areas that may be beneficial for future environmental risk assessments of RNAi-based genetically modified plants, with a particular focus on non-target organism assessment. PMID:26594220

Comparative evaluation of thermal stress of fish in a small pond with a fish shelter

NASA Astrophysics Data System (ADS)

Ahn, Chang Hyuk; Song, Ho Myeon; Park, Jae Ro; Park, Joon-Ha; Jo, Gyu-Hong; Park, Jum-Ok

2018-06-01

This study analyzed the water quality parameters in a fish shelter, which is an artificial structure built in a shallow pond, during early summer. The results of the water quality parameter analyses measured at St. 1 (open water space) and St. 2 (fish shelter) indicated that the fish shelter provides a stable space for fish, with lower water temperatures and less daily water quality variations in the early summer season than the open water space. Due to the temperature reduction and stable effects of these fish shelters, in this study, we found that there was an effect of reducing thermal stress for the Acheilognathinae during early summer. As such, if the fish shelter is introduced into the small pond applied to the urban area, it can be effective for reducing the thermal stress of the Acheilognathinae. In the future, we will need to carry out more detailed research based on this data.

Microprobe studies of microtomed particles of white druse salts in shergottite EETA 79001

NASA Technical Reports Server (NTRS)

Lindstrom, D. J.

1991-01-01

The white druse material in Antarctic shergottite EETA 79001 has attracted much attention as a possible sample fo Martian aqueous deposits. Instrumental Neutron Activation Analysis (INAA) was used to determine trace element analyses of small particles of this material obtained by handpicking of likely grains from broken surfaces of the meteorite. Electron microprobe work was attempted on grain areas as large as 150x120 microns. Backscattered electron images show considerable variations in brightness, and botryoidal structures were observed. Microprobe analyses showed considerable variability both within single particles and between different particles. Microtomed surfaces of small selected particles were shown to be very useful in obtaining information on the texture and composition of rare lithologies like the white druse of EETA 79001. This material is clearly heterogeneous on all distance scales, so a large number of further analyses will be required to characterize it.

The Small Size Debris Population at GEO from Optical Observations

NASA Technical Reports Server (NTRS)

Seitzer, Patrick; Barker, Ed; Buckalew, Brent; Burkhardt, Andrew; Cowardin, Heather; Frith, James; Kaleida, Catherine; Lederer, Susan M.; Lee, Chris H.

2017-01-01

We have observed the geosynchronous orbit (GEO) debris population at sizes smaller than 10 cm using optical observations with the 6.5-m Magellan telescope 'Walter Baade' at the Las Campanas Observatory in Chile. The IMACS f/2 imaging camera with a 0.5-degree diameter field of view has been used in small area surveys of the GEO regime to study the population of optically faint GEO debris. The goal is to estimate the population of GEO debris that is fainter than can be studied with 1-meter class telescopes. A significant population of objects fainter than R = 19th magnitude has been found. These objects have observed with angular rates consistent with circular orbits and orbital inclinations up to 15 degrees at GEO. A sizeable number of these objects have significant brightness variations ("flashes") during the 5-second exposure, which suggest rapid changes in the albedo-projected size product.

Variation in capture efficiency of a beach seine for small fishes

USGS Publications Warehouse

Parsley, M.J.; Palmer, D.E.; Burkhardt, R.W.

1989-01-01

We determined the capture efficiency of a beach seine as a means of improving abundance estimates of small fishes in littoral areas. Capture efficiency for 14 taxa (individual species or species groups) was determined by seining within an enclosure at night over fine and coarse substrates in the John Day Reservoir, Oregon–Washington. Mean efficiency ranged from 12% for prickly sculpin Cottus asper captured over coarse substrates to 96% for peamouth Mylocheilus caurinus captured over fine substrates. Mean capture efficiency for a taxon (genus or species) was generally higher over fine substrates than over coarse substrates, although mean capture efficiencies over fine substrates were significantly greater for only 3 of 10 taxa. Capture efficiency generally was not influenced by fish density or by water temperature (range, 8–26°C). Conclusions about the relative abundance of taxa captured by seining can change substantially after capture efficiencies are taken into account.

Land use determinants of small mammal abundance and distribution in a plague endemic area of Lushoto District, Tanzania.

PubMed

Hieronimo, Proches; Kimaro, Didas N; Kihupi, Nganga I; Gulinck, Hubert; Mulungu, Loth S; Msanya, Balthazar M; Leirs, Herwig; Deckers, Jozef A

2014-07-01

Small mammals are considered to be involved in the transmission cycle of bubonic plague, still occurring in different parts of the world, including the Lushoto District in Tanzania. The objective of this study was to determine the relationship between land use types and practices and small mammal abundance and distribution. A field survey was used to collect data in three landscapes differing in plague incidences. Data collection was done both in the wet season (April-June 2012) and dry season (August-October 2012). Analysis of variance and Boosted Regression Trees (BRT) modelling technique were used to establish the relationship between land use and small mammal abundance and distribution. Significant variations (p ≤ 0.05) of small mammal abundance among land use types were identified. Plantation forest with farming, natural forest and fallow had higher populations of small mammals than the other aggregated land use types. The influence of individual land use types on small mammal abundance level showed that, in both dry and wet seasons, miraba and fallow tended to favour small mammals' habitation whereas land tillage practices had the opposite effect. In addition, during the wet season crop types such as potato and maize appeared to positively influence the distribution and abundance of small mammals which was attributed to both shelter and food availability. Based on the findings from this study it is recommended that future efforts to predict and map spatial and temporal human plague infection risk at fine scale should consider the role played by land use and associated human activities on small mammal abundance and distribution.

A direct correlation among indoor Rn, soil gas Rn and geology in the Reading Prong near Boyertown, Pennsylvania

USGS Publications Warehouse

Reimer, G.M.; Gundersen, L.C.S.

1989-01-01

We feel that this study suggests a relationship among geology, soil gas Rn and the potential for indoor Rn accumulation in this portion of the Reading Prong. There are deviations from a perfect correlation but these are related to inhomogeneities in the geologic environment and perhaps variations in construction techniques of homes in the area. This study also demonstrates that several analyses in a small area may be necessary to adequately determine the Rn distribution for a particular geologic unit. That scale would be determined by the complexity of the local geology. Where no discrete source of elevated Rn supply is found for dwellings having a significant Rn accumulation, the implication is that overall gross permeability may be sufficient to supply Rn from a larger volume of soil and rock.

Morphological analysis of GeTe in inline phase change switches

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

King, Matthew R., E-mail: matthew.king2@ngc.com; Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695; El-Hinnawy, Nabil

2015-09-07

Crystallization and amorphization phenomena in indirectly heated phase change material-based devices were investigated. Scanning transmission electron microscopy was utilized to explore GeTe phase transition processes in the context of the unique inline phase change switch (IPCS) architecture. A monolithically integrated thin film heating element successfully converted GeTe to ON and OFF states. Device cycling prompted the formation of an active area which sustains the majority of structural changes during pulsing. A transition region on both sides of the active area consisting of polycrystalline GeTe and small nuclei (<15 nm) in an amorphous matrix was also observed. The switching mechanism, determined bymore » variations in pulsing parameters, was shown to be predominantly growth-driven. A preliminary model for crystallization and amorphization in IPCS devices is presented.« less

[Application of BaSO4 diffuser plate in 250-400 nm spectral radiance calibration].

PubMed

Jia, Hui; Li, Fu-tian

2004-01-01

Sprayed BaSO4 diffuser plate is the most Lambertian surface actually used in spectral radiance calibration known by now. Its hemispheric reflectance and Bi-directional Reflectance Distribution Functions (BRDF) were measured in the experiment. Its diffuse characteristics were compared with Lambertian surface. In order to calibrate spectral radiance more accurately, the small variation of diffuser's BRDF with scattered angles and the nonuniformity of spectral irradiance on diffuser surface illuminated by the standard lamp should be considered. By integrating the radiation flux reflected by the element area and that entering the entrance slit within the viewing area of spectrometer, the measured spectral radiance can be calculated. Furthermore, the spectral radiance of Lambertian surface whose BRDF was derived from hemispheric reflectance was compared with that from the average of the measured BRDF.

Modelling Coastal Cliff Recession Based on the GIM-DDD Method

NASA Astrophysics Data System (ADS)

Gong, Bin; Wang, Shanyong; Sloan, Scott William; Sheng, Daichao; Tang, Chun'an

2018-04-01

The unpredictable and instantaneous collapse behaviour of coastal rocky cliffs may cause damage that extends significantly beyond the area of failure. Gravitational movements that occur during coastal cliff recession involve two major stages: the small deformation stage and the large displacement stage. In this paper, a method of simulating the entire progressive failure process of coastal rocky cliffs is developed based on the gravity increase method (GIM), the rock failure process analysis method and the discontinuous deformation analysis method, and it is referred to as the GIM-DDD method. The small deformation stage, which includes crack initiation, propagation and coalescence processes, and the large displacement stage, which includes block translation and rotation processes during the rocky cliff collapse, are modelled using the GIM-DDD method. In addition, acoustic emissions, stress field variations, crack propagation and failure mode characteristics are further analysed to provide insights that can be used to predict, prevent and minimize potential economic losses and casualties. The calculation and analytical results are consistent with previous studies, which indicate that the developed method provides an effective and reliable approach for performing rocky cliff stability evaluations and coastal cliff recession analyses and has considerable potential for improving the safety and protection of seaside cliff areas.

Spatio-temporal analysis of small-area intestinal parasites infections in Ghana.

PubMed

Osei, F B; Stein, A

2017-09-22

Intestinal parasites infection is a major public health burden in low and middle-income countries. In Ghana, it is amongst the top five morbidities. In order to optimize scarce resources, reliable information on its geographical distribution is needed to guide periodic mass drug administration to populations of high risk. We analyzed district level morbidities of intestinal parasites between 2010 and 2014 using exploratory spatial analysis and geostatistics. We found a significantly positive Moran's Index of spatial autocorrelation for each year, suggesting that adjoining districts have similar risk levels. Using local Moran's Index, we found high-high clusters extending towards the Guinea and Sudan Savannah ecological zones, whereas low-low clusters extended within the semi-deciduous forest and transitional ecological zones. Variograms indicated that local and regional scale risk factors modulate the variation of intestinal parasites. Poisson kriging maps showed smoothed spatially varied distribution of intestinal parasites risk. These emphasize the need for a follow-up investigation into the exact determining factors modulating the observed patterns. The findings also underscored the potential of exploratory spatial analysis and geostatistics as tools for visualizing the spatial distribution of small area intestinal worms infections.

Nanometric Integrated Temperature and Thermal Sensors in CMOS-SOI Technology.

PubMed

Malits, Maria; Nemirovsky, Yael

2017-07-29

This paper reviews and compares the thermal and noise characterization of CMOS (complementary metal-oxide-semiconductor) SOI (Silicon on insulator) transistors and lateral diodes used as temperature and thermal sensors. DC analysis of the measured sensors and the experimental results in a broad (300 K up to 550 K) temperature range are presented. It is shown that both sensors require small chip area, have low power consumption, and exhibit linearity and high sensitivity over the entire temperature range. However, the diode's sensitivity to temperature variations in CMOS-SOI technology is highly dependent on the diode's perimeter; hence, a careful calibration for each fabrication process is needed. In contrast, the short thermal time constant of the electrons in the transistor's channel enables measuring the instantaneous heating of the channel and to determine the local true temperature of the transistor. This allows accurate "on-line" temperature sensing while no additional calibration is needed. In addition, the noise measurements indicate that the diode's small area and perimeter causes a high 1/ f noise in all measured bias currents. This is a severe drawback for the sensor accuracy when using the sensor as a thermal sensor; hence, CMOS-SOI transistors are a better choice for temperature sensing.

Variations in the prevalence of antibody to brucella infection in cattle by farm, area and district in Kenya.

PubMed Central

Kadohira, M.; McDermott, J. J.; Shoukri, M. M.; Kyule, M. N.

1997-01-01

Variations in the sero-prevalence of antibody to brucella infection by cow, farm and area factors were investigated for three contrasting districts in Kenya: Samburu, an arid and pastoral area: Kiambu, a tropical highland area; and Kilifi, a typical tropical coastal area. Cattle were selected by a two-stage cluster sampling procedure and visited once between August 1991 and 1992. Schall's algorithm, a statistical model suitable for multi-level analysis was used. Using this model, older age, free grazing and large herd size (> or = 31) were associated with higher seroprevalence. Also, significant farm-to-farm, area-to-area and district-to-district variations were estimated. The patterns of high risk districts and areas seen were consistent with known animal husbandry and movement risk factors, but the larger than expected farm-to-farm variation within high risk areas and districts could not be explained. Thus, a multi-level method provided additional information beyond conventional analyses of sero-prevalence data. PMID:9042033

Hydrologic, Ecologic and Livelihood Impact Assessment of a System of Small Reservoirs in Ghana

NASA Astrophysics Data System (ADS)

Gao, Y.; Vogel, R. M.; Kirshen, P. H.; Walker, P.

2012-12-01

In Ghana, the short rainy season is marked by large fluctuations in arrival time, duration and intensity of rainfall, resulting in large inter-year variations in river flow and water availability. Many small reservoirs are built to deal with this variation by providing storage of water in the rainy season. This water is then used during the dry season for various activities, such as small-scale irrigation, domestic uses and livestock watering, to improve livelihood. However, small reservoir development has been made in a spontaneous fashion without concern for their integrated impacts and many of them have deteriorated over time due to poor maintenance. This is further confounded by the lack of a complete inventory of the reservoirs, because their construction was funded by different agencies, at different times, with little coordinated effort among the agencies to facilitate a regional optimization of investments. When an individual small reservoir is considered, alteration to the entire watershed is not significant. However, when considered as a system, together the small reservoirs store a significant quantity of water and influence downstream flows. The small reservoirs have rarely been considered as a system, thus little consideration has been given to their collective impact on the environment and livelihoods of the local population in the long term. Furthermore, the impact is difficult to quantify given the diffuse nature of the small reservoirs. Therefore, this study was set up to investigate the effect of the small reservoirs as a system, and intended to contribute to the limited number of studies available in literature on small reservoirs in developing countries. Using data collected in the Upper East Region of Ghana in 2007 and 2008, hydrological modeling, statistical analyses and institutional analyses were conducted to 1) assess the hydrologic, ecologic and livelihood impact of a large ensemble of small reservoirs; 2) formulate appropriate water policy and planning strategies if any negative impact is found; and 3) provide recommendation on management of small reservoirs with the goal of improving livelihoods. Results from the study show that the current level of small reservoirs development has very low impact on the flow regime in the watershed and that the small reservoirs have not caused any change to the ecosystem in the study area. Small reservoirs can have positive impacts on the farmers' livelihood, but there are issues with the functioning of the water users association (WUA), which an entity established to manage the small reservoirs. Capacity building should be given to the WUA to strengthen its operation, and monitoring of the performance of the WUA and its executive board should be conducted by the Ministry of Food and Agriculture or the funding agency to ensure that the WUA is functioning in a participatory and fair way.

Population Size Estimates for Men who Have Sex with Men and Persons who Inject Drugs.

PubMed

Oster, Alexandra M; Sternberg, Maya; Lansky, Amy; Broz, Dita; Wejnert, Cyprian; Paz-Bailey, Gabriela

2015-08-01

Understanding geographic variation in the numbers of men who have sex with men (MSM) and persons who inject drugs (PWID) is critical to targeting and scaling up HIV prevention programs, but population size estimates are not available at generalizable sub-national levels. We analyzed 1999-2010 National Health and Nutrition Examination Survey data on persons aged 18-59 years. We estimated weighted prevalence of recent (past 12 month) male-male sex and injection drug use by urbanicity (the degree to which a geographic area is urban) and US census region and calculated population sizes. Large metro areas (population ≥1,000,000) had higher prevalence of male-male sex (central areas, 4.4% of men; fringe areas, 2.5%) compared with medium/small metro areas (1.4%) and nonmetro areas (1.1%). Injection drug use did not vary by urbanicity and neither varied by census region. Three-quarters of MSM, but only half of PWID, resided in large metro areas. Two-thirds of MSM and two-thirds of PWID resided in the South and West. Efforts to reach MSM would benefit from being focused in large metro areas, while efforts to reach PWID should be delivered more broadly. These data allow for more effective allocation of funds for prevention programs.

Seasonal variation in orthopedic health services utilization in Switzerland: the impact of winter sport tourism.

PubMed

Matter-Walstra, Klazien; Widmer, Marcel; Busato, André

2006-03-03

Climate- or holiday-related seasonality in hospital admission rates is well known for many diseases. However, little research has addressed the impact of tourism on seasonality in admission rates. We therefore investigated the influence of tourism on emergency admission rates in Switzerland, where winter and summer leisure sport activities in large mountain regions can generate orthopedic injuries. Using small area analysis, orthopedic hospital service areas (HSAo) were evaluated for seasonality in emergency admission rates. Winter sport areas were defined using guest bed accommodation rate patterns of guest houses and hotels located above 1000 meters altitude that show clear winter and summer peak seasons. Emergency admissions (years 2000-2002, n = 135'460) of local and nonlocal HSAo residents were evaluated. HSAo were grouped according to their area type (regular or winter sport area) and monthly analyses of admission rates were performed. Of HSAo within the defined winter sport areas 70.8% show a seasonal, summer-winter peak hospital admission rate pattern and only 1 HSAo outside the defined winter sport areas shows such a pattern. Seasonal hospital admission rates in HSAo in winter sport areas can be up to 4 times higher in winter than the intermediate seasons, and they are almost entirely due to admissions of nonlocal residents. These nonlocal residents are in general -and especially in winter- younger than local residents, and nonlocal residents have a shorter length of stay in winter sport than in regular areas. The overall geographic distribution of nonlocal residents admitted for emergencies shows highest rates during the winter as well as the summer in the winter sport areas. Small area analysis using orthopedic hospital service areas is a reliable method for the evaluation of seasonality in hospital admission rates. In Switzerland, HSAo defined as winter sport areas show a clear seasonal fluctuation in admission rates of only nonlocal residents, whereas HSAo defined as regular, non-winter sport areas do not show such seasonality. We conclude that leisure sport, and especially ski/snowboard tourism demands great flexibility in hospital beds, staff and resource planning in these areas.

Seasonal variation in orthopedic health services utilization in Switzerland: The impact of winter sport tourism

PubMed Central

Matter-Walstra, Klazien; Widmer, Marcel; Busato, André

2006-01-01

Background Climate- or holiday-related seasonality in hospital admission rates is well known for many diseases. However, little research has addressed the impact of tourism on seasonality in admission rates. We therefore investigated the influence of tourism on emergency admission rates in Switzerland, where winter and summer leisure sport activities in large mountain regions can generate orthopedic injuries. Methods Using small area analysis, orthopedic hospital service areas (HSAo) were evaluated for seasonality in emergency admission rates. Winter sport areas were defined using guest bed accommodation rate patterns of guest houses and hotels located above 1000 meters altitude that show clear winter and summer peak seasons. Emergency admissions (years 2000–2002, n = 135'460) of local and nonlocal HSAo residents were evaluated. HSAo were grouped according to their area type (regular or winter sport area) and monthly analyses of admission rates were performed. Results Of HSAo within the defined winter sport areas 70.8% show a seasonal, summer-winter peak hospital admission rate pattern and only 1 HSAo outside the defined winter sport areas shows such a pattern. Seasonal hospital admission rates in HSAo in winter sport areas can be up to 4 times higher in winter than the intermediate seasons, and they are almost entirely due to admissions of nonlocal residents. These nonlocal residents are in general -and especially in winter- younger than local residents, and nonlocal residents have a shorter length of stay in winter sport than in regular areas. The overall geographic distribution of nonlocal residents admitted for emergencies shows highest rates during the winter as well as the summer in the winter sport areas. Conclusion Small area analysis using orthopedic hospital service areas is a reliable method for the evaluation of seasonality in hospital admission rates. In Switzerland, HSAo defined as winter sport areas show a clear seasonal fluctuation in admission rates of only nonlocal residents, whereas HSAo defined as regular, non-winter sport areas do not show such seasonality. We conclude that leisure sport, and especially ski/snowboard tourism demands great flexibility in hospital beds, staff and resource planning in these areas. PMID:16512923

Earth Observations taken by the Expedition 16 Crew

NASA Image and Video Library

2008-01-11

ISS016-E-022772 (11 Jan. 2008) --- Perth, Australia is featured in this image photographed by an Expedition 16 crewmember on the International Space Station (ISS). Perth is the capital of the state of Western Australia, and the largest city of the southwestern continent of Australia with an estimated population of over 1.5 million (December 2006). The downtown area of Perth and the surrounding suburbs are located on flood plain deposits of the Swan and Canning Rivers that flow through the center of the metropolitan area. Perth enjoys a Mediterranean climate, where the summers are hot and dry and winters are cool and moist. Wildfires can develop during the summer months; several large fires threatened the eastern portion of the metropolitan area in 2005. This view captures variations in urban land cover in the visible wavelengths to which the human eye is sensitive (visible red, green, and blue). The downtown center of Perth at left is characterized by large buildings (such as skyscrapers) with white reflective rooftops. Suburbs to the south (across the Swan River) are characterized by higher density of small buildings with predominantly reddish-purple roofs. Several areas of green vegetation are visible in the image. Parks and golf courses comprised mainly of grass present an even green coloration, while the dense tree canopy of Kings Park appears dark green. Variations in the coloration of the Swan and Canning Rivers is due to sunglint, or light reflected off the water surface back to the observer (in this case, a crewmember onboard the ISS).

Diversity and Distribution Patterns of Cetaceans in the Subtropical Southwestern Atlantic Outer Continental Shelf and Slope

PubMed Central

Di Tullio, Juliana Couto; Gandra, Tiago B. R.; Zerbini, Alexandre N.; Secchi, Eduardo R.

2016-01-01

Temporal and spatial patterns of cetacean diversity and distribution were investigated through eight ship-based surveys carried out during spring and autumn between 2009 and 2014 on the outer continental shelf (~150m) and slope (1500m) off southeastern and southern Brazil (~23°S to ~34°S). The survey area was divided into southeast and south areas according to their oceanographic characteristics. Twenty-one species were observed in 503 sightings. The overall number of species was similar between the two areas, though it was higher in the spring in the south area. Five species were dominant and diversity varied more seasonally than spatially. ANOVA and kernel analyses showed that overall cetacean densities were higher in spring compared to autumn. Physeter macrocephalus, the most frequent species, concentrated throughout the south area at depths over 1000m in both seasons. Despite the overlapped occurrence at a broader scale, small delphinids presented latitudinal and in-offshore gradients as well as seasonal variation in distribution patterns, which could indicate habitat partitioning between some species. Delphinus delphis was only recorded in the south and its density decreased in areas where the presence of Stenella frontalis increased, mainly beyond the 250m isobath. Densities of S. longirostris and S. attenuata increased in lower latitudes and beyond the shelf break. The large delphinids Tursiops truncatus and Globicephala melas formed mixed groups in many occasions and were observed along the study area around depths of 500m. Grampus griseus was twice as frequent in the south area and densities increased in waters deeper than 600m. As expected, densities of both small and large migratory whales were higher during spring, over the continental slope, in the southeast area. The results presented here provided strong evidence on the importance of the outer continental shelf and slope to a diverse community of cetaceans occurring in the subtropical Southwestern Atlantic. PMID:27243455

Diversity and Distribution Patterns of Cetaceans in the Subtropical Southwestern Atlantic Outer Continental Shelf and Slope.

PubMed

Di Tullio, Juliana Couto; Gandra, Tiago B R; Zerbini, Alexandre N; Secchi, Eduardo R

2016-01-01

Temporal and spatial patterns of cetacean diversity and distribution were investigated through eight ship-based surveys carried out during spring and autumn between 2009 and 2014 on the outer continental shelf (~150m) and slope (1500m) off southeastern and southern Brazil (~23°S to ~34°S). The survey area was divided into southeast and south areas according to their oceanographic characteristics. Twenty-one species were observed in 503 sightings. The overall number of species was similar between the two areas, though it was higher in the spring in the south area. Five species were dominant and diversity varied more seasonally than spatially. ANOVA and kernel analyses showed that overall cetacean densities were higher in spring compared to autumn. Physeter macrocephalus, the most frequent species, concentrated throughout the south area at depths over 1000m in both seasons. Despite the overlapped occurrence at a broader scale, small delphinids presented latitudinal and in-offshore gradients as well as seasonal variation in distribution patterns, which could indicate habitat partitioning between some species. Delphinus delphis was only recorded in the south and its density decreased in areas where the presence of Stenella frontalis increased, mainly beyond the 250m isobath. Densities of S. longirostris and S. attenuata increased in lower latitudes and beyond the shelf break. The large delphinids Tursiops truncatus and Globicephala melas formed mixed groups in many occasions and were observed along the study area around depths of 500m. Grampus griseus was twice as frequent in the south area and densities increased in waters deeper than 600m. As expected, densities of both small and large migratory whales were higher during spring, over the continental slope, in the southeast area. The results presented here provided strong evidence on the importance of the outer continental shelf and slope to a diverse community of cetaceans occurring in the subtropical Southwestern Atlantic.

Short-term disturbance by a commercial two-dimensional seismic survey does not lead to long-term displacement of harbour porpoises

PubMed Central

Thompson, Paul M.; Brookes, Kate L.; Graham, Isla M.; Barton, Tim R.; Needham, Keith; Bradbury, Gareth; Merchant, Nathan D.

2013-01-01

Assessments of the impact of offshore energy developments are constrained because it is not known whether fine-scale behavioural responses to noise lead to broader-scale displacement of protected small cetaceans. We used passive acoustic monitoring and digital aerial surveys to study changes in the occurrence of harbour porpoises across a 2000 km2 study area during a commercial two-dimensional seismic survey in the North Sea. Acoustic and visual data provided evidence of group responses to airgun noise from the 470 cu inch array over ranges of 5–10 km, at received peak-to-peak sound pressure levels of 165–172 dB re 1 µPa and sound exposure levels (SELs) of 145–151 dB re 1 µPa2 s−1. However, animals were typically detected again at affected sites within a few hours, and the level of response declined through the 10 day survey. Overall, acoustic detections decreased significantly during the survey period in the impact area compared with a control area, but this effect was small in relation to natural variation. These results demonstrate that prolonged seismic survey noise did not lead to broader-scale displacement into suboptimal or higher-risk habitats, and suggest that impact assessments should focus on sublethal effects resulting from changes in foraging performance of animals within affected sites. PMID:24089338

Temporal Variability of Suspended Sediment Load, Dissolved Load, and Bedload for Two Small Oak Forested Catchments with Contrasting Disturbance Levels in the Lesser Himalaya of North-West India

NASA Astrophysics Data System (ADS)

Qazi, N. U. Q.; Rai, S. P.; Bruijnzeel, L. A.

2014-12-01

Sediment transfer from mountainous areas to lowland areas is one of the most important geomorphological processes globally with the bulk of the sediment yield from such areas typically deriving from mass wastage processes. This study presents monthly, seasonal and annual variations in sediment transport (both suspended load and bed load) as well as dissolved loads over three consecutive water years (2008-2011) for two small forested watersheds with contrasting levels of forest disturbance in the Lesser Himalaya of Northwest India. Seasonal and annual suspended sediment yields were strongly influenced by amounts of rainfall and stream flow and showed a 23-fold range between wet and dry years. Of the annual load, some 92% was produced on average during the monsoon season (June-September). Sediment production by the disturbed forest catchment was 2.6-fold (suspended sediment) to 5.9-fold (bed load) higher than that for the well-stocked forest catchment. By contrast, dissolved loads varied much less between years, seasons (although minimal during the dry summer season), and degree of forest disturbance. Total mechanical denudation rates were 1.2 times and 4.7 times larger than chemical denudation rates for the little disturbed and the heavily disturbed forest catchment, respectively whereas overall denudation rates were estimated at 0.59 and 1.05 mm per 1000 years, respectively.

THE TWO REGIMES OF PHOTOSPHERIC MOTIONS IN {alpha} HYDRA

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

Gray, David F., E-mail: dfgray@uwo.ca

2013-02-10

High-resolution spectroscopic observations of {alpha} Hya were acquired between 2003 and 2010. Analysis of line shifts, differential shifts, line widths, and line bisectors points to two regimes of velocity fields in the photosphere of {alpha} Hya: (1) normal granulation embedded in (2) large convection cells. Variations occur on a wide range of timescales, from several years on down. Radial velocity variations, which are irregular and span 786 m s{sup -1}, have a distribution consistent with a true mean rise velocity of the large cells of {approx}725 m s{sup -1} and a dispersion of {approx}220 m s{sup -1}. The distribution ofmore » granulation velocities, as measured from the widths of spectral lines, shows only small variations, consistent with the two regime concepts. On the multi-year timescale, radial velocity changes, small temperature variations ({approx}10 K), and small line-width variations ({approx}<0.8%) track each other, possibly with phase shifts. The granulation velocity gradient for {alpha} Hya is about half as large as the Sun's and no variation with time was seen, implying that any variation in velocity gradient from one large cell to the next must be less than a few percent. The asymmetry in the granulation velocity distribution, as specified in the flux deficit, is smaller than expected for {alpha} Hya's position in the HR diagram and appears to be variable.« less

Infrared-temperature variability in a large agricultural field

NASA Technical Reports Server (NTRS)

Millard, J. P.; Goettelman, R. C.; Leroy, M. J.

1981-01-01

Dunnigan Agro-Meteorological Experiment airborne thermal scanner images of a large varying-terrain barley field are acquired and analyzed. Temperature variability that may occur within instantaneous fields of view (IFOV) is defined (coefficient of variation: standard deviation/mean temperature in degrees C), and the percentage of the area within various IFOV's within + or - 1, 2, 3, and 5 degrees of the mean is determined. With the exception of very rugged terrain, over 80% of the area within 4, 16, 65 and 258 ha cells was at temperatures within + or - 3 C of the mean cell temperature. Remote measurements of field temperature appeared to be slightly influenced by pixel size in the range 4 ha to 259 ha, and the area percentage within any pixel which contributes within + or - 1, 2, 3, and 5 degrees C of the mean, is nominally the same. In conclusion, no great advantage is found in utilizing a small IFOV instead of a large one for remote sensing of crop temperature.

Mesoscale monitoring of the soil freeze/thaw boundary from orbital microwave radiometry

NASA Technical Reports Server (NTRS)

Dobson, Craig; Ulaby, Fawwaz T.; Zuerndorfer, Brian; England, Anthony W.

1990-01-01

A technique was developed for mapping the spatial extent of frozen soils from the spectral characteristics of the 10.7 to 37 GHz radiobrightness. Through computational models for the spectral radiobrightness of diurnally heated freesing soils, a distinctive radiobrightness signature was identified for frozen soils, and the signature was cast as a discriminant for unsupervised classification. In addition to large area images, local area spatial averages of radiobrightness were calculated for each radiobrightness channel at 7 meteorologic sites within the test region. Local area averages at the meteorologic sites were used to define the preliminary boundaries in the Freeze Indicator discriminate. Freeze Indicator images based upon Nimbus 7, Scanning Multichannel Microwave Radiometer (SMMR) data effectively map temporal variations in the freeze/thaw pattern for the northern Great Plains at the time scale of days. Diurnal thermal gradients have a small but measurable effect upon the SMMR spectral gradient. Scale-space filtering can be used to improve the spatial resolution of a freeze/thaw classified image.

A Study of Sociolinguistic Variation in a Small Community: Puerto Rican Spanish in Amsterdam, New York

ERIC Educational Resources Information Center

Mumin, Zahir

2017-01-01

The objective of the current study is to contribute to the larger body of sociophonetic variation research by describing and analyzing Spanish as spoken in a small Puerto Rican community in the US. First, I describe phonological and morphosyntactic features of Spanish as used by four different groups of Puerto Rican informants in Amsterdam, New…

[Entomologic study on the transmission of onchocerciasis in a forest-savanna transition area of Cameroon].

PubMed

Barbazan, P; Escaffre, H; Mbentengam, R; Boussinesq, M

1998-01-01

An entomological study was conducted in the basin area of middle Sanaga (Cameroon) in order to document the pattern of onchocerciasis transmission in a region where a high prevalence of infection had been recorded in villages located 30 km from the main rivers. The main vector of O. volvulus was found to be S. squamosum s.s. No breeding site was found in the small tributaries of the Sanaga and Mbam Rivers, and the dispersal of S. damnosum s.l. in the area thus appeared to be particularly high. The highest blackfly population densities were recorded during the long rainy season, and a second peak of density occurred along the Mbam River during the short rainy season. A seasonal variation in dispersal patterns was found at three of the four transects studied. The transmission of Onchocerca volvulus in the area occurred principally between January and May (i.e. at the end of the long dry season and the beginning of the short rainy season). Vector control operations might well reinforce the effect of ivermectin distributions in this onchocerciasis focus.

Reducing the number of reconstructions needed for estimating channelized observer performance

NASA Astrophysics Data System (ADS)

Pineda, Angel R.; Miedema, Hope; Brenner, Melissa; Altaf, Sana

2018-03-01

A challenge for task-based optimization is the time required for each reconstructed image in applications where reconstructions are time consuming. Our goal is to reduce the number of reconstructions needed to estimate the area under the receiver operating characteristic curve (AUC) of the infinitely-trained optimal channelized linear observer. We explore the use of classifiers which either do not invert the channel covariance matrix or do feature selection. We also study the assumption that multiple low contrast signals in the same image of a non-linear reconstruction do not significantly change the estimate of the AUC. We compared the AUC of several classifiers (Hotelling, logistic regression, logistic regression using Firth bias reduction and the least absolute shrinkage and selection operator (LASSO)) with a small number of observations both for normal simulated data and images from a total variation reconstruction in magnetic resonance imaging (MRI). We used 10 Laguerre-Gauss channels and the Mann-Whitney estimator for AUC. For this data, our results show that at small sample sizes feature selection using the LASSO technique can decrease bias of the AUC estimation with increased variance and that for large sample sizes the difference between these classifiers is small. We also compared the use of multiple signals in a single reconstructed image to reduce the number of reconstructions in a total variation reconstruction for accelerated imaging in MRI. We found that AUC estimation using multiple low contrast signals in the same image resulted in similar AUC estimates as doing a single reconstruction per signal leading to a 13x reduction in the number of reconstructions needed.

Exceptional preservation of children's footprints from a Holocene footprint site in Namibia

NASA Astrophysics Data System (ADS)

Bennett, Matthew R.; Morse, Sarita A.; Liutkus-Pierce, Cynthia; McClymont, Juliet; Evans, Mary; Crompton, Robin H.; Francis Thackeray, J.

2014-09-01

Here we report on a Holocene inter-dune site close to Walvis Bay (Namibia) which contains exceptionally well-preserved children's footprints. The footprint surface is dated using Optically Stimulated Luminescence (OSL) methods to approximately 1.5 ka. These dates are compared to those obtained at nearby footprint sites and used to verify a model of diachronous footprint surfaces and also add to the archaeological data available for the communities that occupied these near-coastal areas during the Holocene. This model of diachronous footprint surfaces has implications for other soft-sediment footprint sites such as the 1.5 Ma old footprints at Ileret (Kenya). The distribution of both human and animal tracks, is consistent with the passage of small flock of small ungulates (probably sheep/goats) followed by a group of approximately 9 ± 2 individuals (children or young adults). Age estimates from the tracks suggest that some of the individuals may have been as young as five years old. Variation in track topology across this sedimentologically uniform surface is explained in terms of variations in gait and weight/stature of the individual print makers and is used to corroborate a model of footprint morphology developed at a nearby site. The significance of the site within the literature on human footprints lies in the quality of the track preservation, their topological variability despite a potentially uniform substrate, and the small size of the tracks, and therefore the inferred young age of the track-makers. The site provides an emotive insight into the life of the track-makers.

"Geography of suicide in Hong Kong: spatial patterning, and socioeconomic correlates and inequalities".

PubMed

Hsu, Chia-Yueh; Chang, Shu-Sen; Lee, Esther S T; Yip, Paul S F

2015-04-01

Past urban research on Western nations tends to show high suicide rates in inner city and socioeconomically deprived areas. However, little is known about geographic variations in suicide in non-Western cities. We used Bayesian hierarchical models to estimate smoothed standardised mortality ratios (2005-2010) for suicide in people aged 10 years or above in each geographic unit in Hong Kong at two levels, i.e. large street block (n = 1639; median population = 1860) and small tertiary planning unit group (n = 204; median population = 14,850). We further analysed their associations with a range of area socioeconomic characteristics and a deprivation index. The "city centre" of Hong Kong, a generally non-deprived area, showed mostly below average suicide rates. However, there were high rates concentrating in some socioeconomically deprived, densely populated areas, including some inner city areas, across the city. Males had greater geographic variations in rates than females, except the elderly group. The use of smaller geographic units revealed finer detailed suicide distribution than the use of larger units, and showed that suicide rates were associated with indicators of socioeconomic deprivation (population with non-professional jobs and low median household income), and social fragmentation (proportions of unmarried adults and divorced/separated adults), but not with Gini coefficient. Sex/age groups had different associations with suicide rates. Areas in the most deprived quintile had a suicide rate more than two times higher than the least deprived. The association between suicide and deprivation was stronger in males than females and more marked in the younger populations compared to the elderly. The spatial distribution of suicide in Hong Kong showed distinct patterning and a stronger association with income compared to findings from Western countries. Suicide prevention strategies should consider tackling the marked socioeconomic gradient in suicide and high risk in young and middle-aged males living in deprived areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

Atmospheric response to Saharan dust deduced from ECMWF reanalysis (ERA) temperature increments

NASA Astrophysics Data System (ADS)

Kishcha, P.; Alpert, P.; Barkan, J.; Kirchner, I.; Machenhauer, B.

2003-09-01

This study focuses on the atmospheric temperature response to dust deduced from a new source of data the European Reanalysis (ERA) increments. These increments are the systematic errors of global climate models, generated in the reanalysis procedure. The model errors result not only from the lack of desert dust but also from a complex combination of many kinds of model errors. Over the Sahara desert the lack of dust radiative effect is believed to be a predominant model defect which should significantly affect the increments. This dust effect was examined by considering correlation between the increments and remotely sensed dust. Comparisons were made between April temporal variations of the ERA analysis increments and the variations of the Total Ozone Mapping Spectrometer aerosol index (AI) between 1979 and 1993. The distinctive structure was identified in the distribution of correlation composed of three nested areas with high positive correlation (>0.5), low correlation and high negative correlation (<-0.5). The innermost positive correlation area (PCA) is a large area near the center of the Sahara desert. For some local maxima inside this area the correlation even exceeds 0.8. The outermost negative correlation area (NCA) is not uniform. It consists of some areas over the eastern and western parts of North Africa with a relatively small amount of dust. Inside those areas both positive and negative high correlations exist at pressure levels ranging from 850 to 700 hPa, with the peak values near 775 hPa. Dust-forced heating (cooling) inside the PCA (NCA) is accompanied by changes in the static instability of the atmosphere above the dust layer. The reanalysis data of the European Center for Medium Range Weather Forecast (ECMWF) suggest that the PCA (NCA) corresponds mainly to anticyclonic (cyclonic) flow, negative (positive) vorticity and downward (upward) airflow. These findings are associated with the interaction between dust-forced heating/cooling and atmospheric circulation. This paper contributes to a better understanding of dust radiative processes missed in the model.

Carbon Cycling of Lake Kivu (East Africa): Net Autotrophy in the Epilimnion and Emission of CO2 to the Atmosphere Sustained by Geogenic Inputs

PubMed Central

Borges, Alberto V.; Morana, Cédric; Bouillon, Steven; Servais, Pierre; Descy, Jean-Pierre; Darchambeau, François

2014-01-01

We report organic and inorganic carbon distributions and fluxes in a large (>2000 km2) oligotrophic, tropical lake (Lake Kivu, East Africa), acquired during four field surveys, that captured the seasonal variations (March 2007–mid rainy season, September 2007–late dry season, June 2008–early dry season, and April 2009–late rainy season). The partial pressure of CO2 (pCO2) in surface waters of the main basin of Lake Kivu showed modest spatial (coefficient of variation between 3% and 6%), and seasonal variations with an amplitude of 163 ppm (between 579±23 ppm on average in March 2007 and 742±28 ppm on average in September 2007). The most prominent spatial feature of the pCO2 distribution was the very high pCO2 values in Kabuno Bay (a small sub-basin with little connection to the main lake) ranging between 11213 ppm and 14213 ppm (between 18 and 26 times higher than in the main basin). Surface waters of the main basin of Lake Kivu were a net source of CO2 to the atmosphere at an average rate of 10.8 mmol m−2 d−1, which is lower than the global average reported for freshwater, saline, and volcanic lakes. In Kabuno Bay, the CO2 emission to the atmosphere was on average 500.7 mmol m−2 d−1 (∼46 times higher than in the main basin). Based on whole-lake mass balance of dissolved inorganic carbon (DIC) bulk concentrations and of its stable carbon isotope composition, we show that the epilimnion of Lake Kivu was net autotrophic. This is due to the modest river inputs of organic carbon owing to the small ratio of catchment area to lake surface area (2.15). The carbon budget implies that the CO2 emission to the atmosphere must be sustained by DIC inputs of geogenic origin from deep geothermal springs. PMID:25314144

Validation of the Small Hot Jet Acoustic Rig for Jet Noise Research

NASA Technical Reports Server (NTRS)

Bridges, James; Brown, Clifford A.

2005-01-01

The development and acoustic validation of the Small Hot Jet Aeroacoustic Rig (SHJAR) is documented. Originally conceived to support fundamental research in jet noise, the rig has been designed and developed using the best practices of the industry. While validating the rig for acoustic work, a method of characterizing all extraneous rig noise was developed. With this in hand, the researcher can know when the jet data being measured is being contaminated and design the experiment around this limitation. Also considered is the question of uncertainty, where it is shown that there is a fundamental uncertainty of 0.5dB or so to the best experiments, confirmed by repeatability studies. One area not generally accounted for in the uncertainty analysis is the variation which can result from differences in initial condition of the nozzle shear layer. This initial condition was modified and the differences in both flow and sound were documented. The bottom line is that extreme caution must be applied when working on small jet rigs, but that highly accurate results can be made independent of scale.

Measurement of surface water runoff from plots of two different sizes

NASA Astrophysics Data System (ADS)

Joel, Abraham; Messing, Ingmar; Seguel, Oscar; Casanova, Manuel

2002-05-01

Intensities and amounts of water infiltration and runoff on sloping land are governed by the rainfall pattern and soil hydraulic conductivity, as well as by the microtopography and soil surface conditions. These components are closely interrelated and occur simultaneously, and their particular contribution may change during a rainfall event, or their effects may vary at different field scales. The scale effect on the process of infiltration/runoff was studied under natural field and rainfall conditions for two plot sizes: small plots of 0·25 m2 and large plots of 50 m2. The measurements were carried out in the central region of Chile in a piedmont most recently used as natural pastureland. Three blocks, each having one large plot and five small plots, were established. Cumulative rainfall and runoff quantities were sampled every 5 min. Significant variations in runoff responses to rainfall rates were found for the two plot sizes. On average, large plots yielded only 40% of runoff quantities produced on small plots per unit area. This difference between plot sizes was observed even during periods of continuous runoff.

The Effect of Area Variation on Wave Rotor Elements

NASA Technical Reports Server (NTRS)

Wilson, Jack

1997-01-01

The effect of varying the cross-sectional flow area of the passages of a wave rotor is examined by means of the method of characteristics. An idealized expansion wave, an idealized inlet port, and an idealized compression stage are considered. It is found that area variation does not have a very significant effect on the expansion wave, nor on the compression stage. For the expansion wave, increasing the passage area in the flow direction has the same effect as a diffuser, so that the flow emerges at a lower velocity than it would for the constant area case. This could be advantageous. The inlet is strongly affected by the area variation, as it changes the strength of the hammer shock wave, thereby changing the pressure behind it. In this case, reduction in the passage area in the flow direction leads to increased pressure. However, this result is dependent on the assumption that the inlet conditions remain constant with area variation. This may not be the case.

Demographic variation across successional stages and their effects on the population dynamics of the neotropical palm Euterpe precatoria.

PubMed

Otárola, Mauricio Fernández; Avalos, Gerardo

2014-06-01

• Premise of the study: Environmental heterogeneity is a strong selective force shaping adaptation and population dynamics across temporal and spatial scales. Natural and anthropogenic gradients influence the variation of environmental and biotic factors, which determine population demography and dynamics. Successional gradients are expected to influence demographic parameters, but the relationship between these gradients and the species life history, habitat requirements, and degree of variation in demographic traits remains elusive.• Methods: We used the palm Euterpe precatoria to test the effect of successional stage on plant demography within a continuous population. We calculated demographic parameters for size stages and performed matrix analyses to investigate the demographic variation within primary and secondary forests of La Selva, Costa Rica.• Key results: We observed differences in mortality and recruitment of small juveniles between primary and secondary forests. Matrix models described satisfactorily the chronosequence of population changes, which were characterized by high population growth rate in disturbed areas, and decreased growth rate in old successional forests until reaching stability.• Conclusions: Different demographic parameters can be expressed in contiguous subpopulations along a gradient of successional stages with important consequences for population dynamics. Demographic variation superimposed on these gradients contributes to generate subpopulations with different demographic composition, density, and ecological properties. Therefore, the effects of spatial variation must be reconsidered in the design of demographic analyses of tropical palms, which are prime examples of subtle local adaptation. These considerations are crucial in the implementation of management plans for palm species within spatially complex and heterogeneous tropical landscapes. © 2014 Botanical Society of America, Inc.

Small area clustering of under-five children's mortality and associated factors using geo-additive Bayesian discrete-time survival model in Kersa HDSS, Ethiopia.

PubMed

Dedefo, Melkamu; Oljira, Lemessa; Assefa, Nega

2016-02-01

Child mortality reflects a country's level of socio-economic development and quality of life. In Ethiopia, limited studies were conducted on under-five mortality and almost none of them tried to identify the spatial effect on mortality. Thus, this study explored the small area clustering of under-five mortality and associated factors in Kersa HDSS, Eastern Ethiopia. The study population included all children under the age of five years during the time September, 2008-august 31, 2012 which are registered in Kersa Health and Demographic Surveillance System (Kersa HDSS). A flexible Bayesian geo-additive discrete-time survival mixed model was used. Some of the factors that are significantly associated with under-five mortality, with posterior odds ratio and 95% credible intervals, are maternal educational status 1.31(1.13,-1.49), place of delivery 1.016(1.013-1.12), no of live birth at a delivery 0.35(0.23,1.83), low household wealth index 1.26(1.10 1.43) middle level household wealth index 0.95 (0.84 1.07) pre-term duration of pregnancy 1.95(1.27,2.91), post-term duration of pregnancy 0.74(0.60,0.93) and antenatal visit 1.19(1.06, 1.35). Variation was noted in the risk of under-five mortality by the selected small administrative regions (kebeles). This study reveals geographic patterns in rates of under-five mortality in those selected small administrative regions and shows some important determinants of under-five mortality. More importantly, we observed clustering of under-five mortality, which indicates the importance of spatial effects and presentation of this clustering through maps that facilitates visuality and highlights differentials across geographical areas that would, otherwise, be overlooked in traditional data-analytic methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

Deposition and Burial Efficiency of Terrestrial Organic Carbon Exported from Small Mountainous Rivers to the Continental Margin, Southwest of Taiwan

NASA Astrophysics Data System (ADS)

Hsu, F.; Lin, S.; Wang, C.; Huh, C.

2007-12-01

Terrestrial organic carbon exported from small mountainous river to the continental margin may play an important role in global carbon cycle and it?|s biogeochemical process. A huge amount of suspended materials from small rivers in southwestern Taiwan (104 million tons per year) could serve as major carbon source to the adjacent ocean. However, little is know concerning fate of this terrigenous organic carbon. The purpose of this study is to calculate flux of terrigenous organic carbon deposited in the continental margin, offshore southwestern Taiwan through investigating spatial variation of organic carbon content, organic carbon isotopic compositions, organic carbon deposition rate and burial efficiency. Results show that organic carbon compositions in sediment are strongly influenced by terrestrial material exported from small rivers in the region, Kaoping River, Tseng-wen River and Er-jan Rver. In addition, a major part of the terrestrial materials exported from the Kaoping River may bypass shelf region and transport directly into the deep sea (South China Sea) through the Kaoping Canyon. Organic carbon isotopic compositions with lighter carbon isotopic values are found near the Kaoping River and Tseng-wen River mouth and rapidly change from heavier to lighter values through shelf to slope. Patches of lighter organic carbon isotopic compositions with high organic carbon content are also found in areas west of Kaoping River mouth, near the Kaoshiung city. Furthermore, terrigenous organic carbons with lighter isotopic values are found in the Kaoping canyon. A total of 0.028 Mt/yr of terrestrial organic carbon was found in the study area, which represented only about 10 percent of all terrestrial organic carbon deposited in the study area. Majority (~90 percent) of the organic carbon exported from the Kaoping River maybe directly transported into the deep sea (South China Sea) and become a major source of organic carbon in the deep sea.

[Effect of Below-cloud Secondary Evaporation in Precipitations over the Loess Plateau Based on the Stable Isotopes of Hydrogen and Oxygen].

PubMed

Jin, Xiao-gang; Zhang, Ming-jun; Wang, Sheng-jie; Zhu, Xiao-fan; Dong, Lei; Ren, Zheng-guo; Chen, Fen-li

2015-04-01

Based on stable isotopes in 409 precipitation samples provided by GNIP and meteorological records at the eight stations in Loess Plateau from January 1985 to December 2004, as well as the trajectory model of HYSPLIT 4.9, the spatial and temporal variations of d-excess and Δ18O were analyzed. The spatial distribution of secondary evaporation rate and the impact of meteorological factors on below-cloud secondary evaporation were also discussed. The result showed that: (1) During summer and winter monsoon periods, Δ18O showed an uptrend variation and d-excess showed a downtrend variation from south to north in Loess Plateau. From east to west, Δ180 showed an uptrend variation only in summer monsoon period and a downtrend variation in winter monsoon period. The value of d-excess also showed a downtrend variation. Amplitude of variation Δ18O and d-excess could indicate the routes of monsoon. (2) Secondary evaporation existed on an annual basis, and it was relatively significant during the summer monsoon period, with ranges from 1.51% to 5.88% and an average rate of 3.87%. While winter monsoon became lower, the rates ranged from 1.06% to 5.46%, and the average rate dropped to 3.03%. Monsoon had larger influence on secondary evaporation in margin area of the plateau, while the influence on the central stations was little. (3) Temperature had the highest contribution to secondary evaporation, followed by precipitation amount and water vapor pressure, and relative humidity had a small contribution. Moreover, the influence of wind speed and altitude on secondary evaporation was weak.

Controls of bedrock geochemistry on soil and plant nutrients in Southeastern Utah

USGS Publications Warehouse

Neff, J.C.; Reynolds, R.; Sanford, R.L.; Fernandez, D.; Lamothe, P.

2006-01-01

The cold deserts of the Colorado Plateau contain numerous geologically and geochemically distinct sedimentary bedrock types. In the area near Canyonlands National Park in Southeastern Utah, geochemical variation in geologic substrates is related to the depositional environment with higher concentrations of Fe, Al, P, K, and Mg in sediments deposited in alluvial or marine environments and lower concentrations in bedrock derived from eolian sand dunes. Availability of soil nutrients to vegetation is also controlled by the formation of secondary minerals, particularly for P and Ca availability, which, in some geologic settings, appears closely related to variation of CaCO3 and Ca-phosphates in soils. However, the results of this study also indicate that P content is related to bedrock and soil Fe and Al content suggesting that the deposition history of the bedrock and the presence of P-bearing Fe and Al minerals, is important to contemporary P cycling in this region. The relation between bedrock type and exchangeable Mg and K is less clear-cut, despite large variation in bedrock concentrations of these elements. We examined soil nutrient concentrations and foliar nutrient concentration of grasses, shrubs, conifers, and forbs in four geochemically distinct field sites. All four of the functional plant groups had similar proportional responses to variation in soil nutrient availability despite large absolute differences in foliar nutrient concentrations and stoichiometry across species. Foliar P concentration (normalized to N) in particular showed relatively small variation across different geochemical settings despite large variation in soil P availability in these study sites. The limited foliar variation in bedrock-derived nutrients suggests that the dominant plant species in this dryland setting have a remarkably strong capacity to maintain foliar chemistry ratios despite large underlying differences in soil nutrient availability. ?? 2006 Springer Science+Business Media, Inc.

Late Pleistocene (MIS5-3) environmental reconstruction from north-eastern Iberia through microvertebrate and palaeobotanical records

NASA Astrophysics Data System (ADS)

Allue, Ethel; Bennàssar, Maria; Biltekin, Demet; Blain, Hugues-Alexandre; Burjachs, Francesc; Euba, Itxaso; Expósito, Isabel; Fernández-García, Mónica; López-García, Juan Manuel

2014-05-01

The aim of this work is to analyze the environmental changes during the Late Pleistocene on the basis of a multi-approach study based on natural and archaeological deposits from NE Iberian Peninsula. The focussed area, although having a small extension (some 32.000 square kilometres), covers a large range of ecosystems and bioclimatic conditions from the Mediterranean seashore to the summit of the Pyrenean mountain ranges (up to 2000 masl). This synthetical approach includes materials from various contexts including 10 archaeological deposits and a single natural deposit. In this work, plant (pollen and charcoals) and animal (small mammals, amphibians and reptiles) records are being analysed and compared in order to present an overview of the environmental changes occurred from the MIS5 to MIS3. On the first hand, we are using the small-vertebrate records recovered from archaeological deposits. These proxies are mainly the product of pellets from birds of prey and are key ecological markers. On the second hand, palaeobotanical evidences, pollen and charcoal, have different formation processes. Charcoal remains are mostly from archaeological deposits and are due to human activities related to fire showing evidences of the local vegetation. Pollen evidences from archaeological and natural contexts are deposited through natural processes (wind, insects, etc.) and show regional scale vegetation record. Results indicate the presence of temperate elements during all these periods (especially at the seashore area), with a more important representation and extension southwards or changes in altitude from taxa with eurosiberian affinities during coldest periods. Forest coverage, plant and vertebrate distribution along the territory point out a mosaic landscape formed by open areas and forests. These landscapes have probably a more or less Mediterranean or Eurosiberian character depending on the climatic moment and their location with variations along the sequence.

Global Biomass Variation and its Geodynamic Effects, 1982-1998

NASA Technical Reports Server (NTRS)

Rodell, M.; Chao, B. F.; Au, A. Y.; Kimball, J. S.; McDonald, K. C.

2005-01-01

Redistribution of mass near Earth's surface alters its rotation, gravity field, and geocenter location. Advanced techniques for measuring these geodetic variations now exist, but the ability to attribute the observed modes to individual Earth system processes has been hampered by a shortage of reliable global data on such processes, especially hydrospheric processes. To address one aspect of this deficiency, 17 yrs of monthly, global maps of vegetation biomass were produced by applying field-based relationships to satellite-derived vegetation type and leaf area index. The seasonal variability of biomass was estimated to be as large as 5 kg m(exp -2). Of this amount, approximately 4 kg m(exp -2) is due to vegetation water storage variations. The time series of maps was used to compute geodetic anomalies, which were then compared with existing geodetic observations as well as the estimated measurement sensitivity of the Gravity Recovery and Climate Experiment (GRACE). For gravity, the seasonal amplitude of biomass variations may be just within GRACE'S limits of detectability, but it is still an order of magnitude smaller than current observation uncertainty using the satellite-laser-ranging technique. The contribution of total biomass variations to seasonal polar motion amplitude is detectable in today's measurement, but it is obscured by contributions from various other sources, some of which are two orders of magnitude larger. The influence on the length of day is below current limits of detectability. Although the nonseasonal geodynamic signals show clear interannual variability, they are too small to be detected.

A Simple Model to Describe the Relationship among Rainfall, Groundwater and Land Subsidence under a Heterogeneous Aquifer

NASA Astrophysics Data System (ADS)

Zheng, Y. Y.; Chen, Y. L.; Lin, H. R.; Huang, S. Y.; Yeh, T. C. J.; Wen, J. C.

2017-12-01

Land subsidence is a very serious problem of Zhuoshui River alluvial fan, Taiwan. The main reason of land subsidence is a compression of soil, but the compression measured in the wide area is very extensive (Maryam et al., 2013; Linlin et al., 2014). Chen et al. [2010] studied the linear relationship between groundwater level and subsurface altitude variations from Global Positioning System (GPS) station in Zhuoshui River alluvial fan. But the subsurface altitude data were only from two GPS stations. Their distributions are spared and small, not enough to express the altitude variations of Zhuoshui River alluvial fan. Hung et al. [2011] used Interferometry Synthetic Aperture Radar (InSAR) to measure the surface subsidence in Zhuoshui River alluvial fan, but haven't compared with groundwater level. The study compares the correlation between rainfall events and groundwater level and compares the correlation between groundwater level and subsurface altitude, these two correlation affected by heterogeneous soil. From these relationships, a numerical model is built to simulate the land subsidence variations and estimate the coefficient of aquifer soil compressibility. Finally, the model can estimate the long-term land subsidence. Keywords: Land Subsidence, InSAR, Groundwater Level, Numerical Model, Correlation Analyses

Integration of Palmer Drought Severity Index and remote sensing data to simulate wetland water surface from 1910 to 2009 in Cottonwood Lake area, North Dakota

USGS Publications Warehouse

Huang, Shengli; Dahal, Devendra; Young, Claudia; Chander, Gyanesh; Liu, Shuguang

2011-01-01

Spatiotemporal variations of wetland water in the Prairie Pothole Region are controlled by many factors; two of them are temperature and precipitation that form the basis of the Palmer Drought Severity Index (PDSI). Taking the 196 km2 Cottonwood Lake area in North Dakota as our pilot study site, we integrated PDSI, Landsat images, and aerial photography records to simulate monthly water surface. First, we developed a new Wetland Water Area Index (WWAI) from PDSI to predict water surface area. Second, we developed a water allocation model to simulate the spatial distribution of water bodies at a resolution of 30 m. Third, we used an additional procedure to model the small wetlands (less than 0.8 ha) that could not be detected by Landsat. Our results showed that i) WWAI was highly correlated with water area with an R2 of 0.90, resulting in a simple regression prediction of monthly water area to capture the intra- and inter-annual water change from 1910 to 2009; ii) the spatial distribution of water bodies modeled from our approach agreed well with the water locations visually identified from the aerial photography records; and iii) the R2 between our modeled water bodies (including both large and small wetlands) and those from aerial photography records could be up to 0.83 with a mean average error of 0.64 km2 within the study area where the modeled wetland water areas ranged from about 2 to 14 km2. These results indicate that our approach holds great potential to simulate major changes in wetland water surface for ecosystem service; however, our products could capture neither the short-term water change caused by intensive rainstorm events nor the wetland change caused by human activities.

Variation of Geochemical Signatures and Correlation of Biomarkers in Icelandic Mars Analogue Environments

NASA Astrophysics Data System (ADS)

Gentry, D.; Amador, E. S.; Cable, M. L.; Cantrell, T.; Chaudry, N.; Cullen, T.; Duca, Z. A.; Jacobsen, M. B.; McCaig, H. C.; Murukesan, G.; Rennie, V.; Schwieterman, E. W.; Stevens, A. H.; Tan, G.; Yin, C.; Stockton, A.; Cullen, D.; Geppert, W.

2015-12-01

Exploration missions to Mars rely on rovers to perform deep analyses over small sampling areas; however, landing site selection is done using large-scale but low-resolution remote sensing data. Using Earth analogue environments to estimate the small-scale spatial and temporal distributions of key geochemical signatures and (for habitability studies) biomarkers helps ensure that the chosen sampling strategies meet mission science goals. We conducted two rounds of analogue expeditions to recent Icelandic lava fields. In July 2013, we tested correlation between three common biomarker assays: cell quantification via fluorescence microscopy, ATP quantification via bioluminescence, and quantitative PCR with universal primer sets. Sample sites were nested at four spatial scales (1 m, 10 m, 100 m, and > 1 km) and homogeneous at 'remote imaging' resolution (overall temperature, apparent moisture content, and regolith grain size). All spatial scales were highly diverse in ATP, bacterial 16S, and archaeal 16S DNA content; nearly half of sites were statistically different in ATP content at α = 0.05. Cell counts showed significant variation at the 10 m and 100 m scale; at the > 1 km scale, the mean counts were not distinguishable, but the median counts were, indicating differences in underlying distribution. Fungal 18S DNA content similarly varied at 1 m, 10 m, and 100 m scales only. Cell counts were not correlated with ATP or DNA content at any scale. ATP concentration and DNA content for all three primer sets were positively correlated. Bacterial DNA content was positively correlated with archaeal and fungal DNA content, though archaeal correlation was weak. Fungal and archaeal correlation was borderline. In July 2015, we repeated the sampling strategy, with the addition of a smaller-scale sampling grid of 10 cm and a third > 1 km location. This expedition also measured reflectance of the tephra cover and preserved mineral samples for future Raman spectroscopy in order to better distinguish between effects of geochemical variation and intrinsic biomarker variation.

Interior region-of-interest reconstruction using a small, nearly piecewise constant subregion

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

Taguchi, Katsuyuki; Xu Jingyan; Srivastava, Somesh

2011-03-15

Purpose: To develop a method to reconstruct an interior region-of-interest (ROI) image with sufficient accuracy that uses differentiated backprojection (DBP) projection onto convex sets (POCS) [H. Kudo et al., ''Tiny a priori knowledge solves the interior problem in computed tomography'', Phys. Med. Biol. 53, 2207-2231 (2008)] and a tiny knowledge that there exists a nearly piecewise constant subregion. Methods: The proposed method first employs filtered backprojection to reconstruct an image on which a tiny region P with a small variation in the pixel values is identified inside the ROI. Total variation minimization [H. Yu and G. Wang, ''Compressed sensing basedmore » interior tomography'', Phys. Med. Biol. 54, 2791-2805 (2009); W. Han et al., ''A general total variation minimization theorem for compressed sensing based interior tomography'', Int. J. Biomed. Imaging 2009, Article 125871 (2009)] is then employed to obtain pixel values in the subregion P, which serve as a priori knowledge in the next step. Finally, DBP-POCS is performed to reconstruct f(x,y) inside the ROI. Clinical data and the reconstructed image obtained by an x-ray computed tomography system (SOMATOM Definition; Siemens Healthcare) were used to validate the proposed method. The detector covers an object with a diameter of {approx}500 mm. The projection data were truncated either moderately to limit the detector coverage to diameter 350 mm of the object or severely to cover diameter 199 mm. Images were reconstructed using the proposed method. Results: The proposed method provided ROI images with correct pixel values in all areas except near the edge of the ROI. The coefficient of variation, i.e., the root mean square error divided by the mean pixel values, was less than 2.0% or 4.5% with the moderate or severe truncation cases, respectively, except near the boundary of the ROI. Conclusions: The proposed method allows for reconstructing interior ROI images with sufficient accuracy with a tiny knowledge that there exists a nearly piecewise constant subregion.« less

Spatial variability of the dose rate from (137)Cs fallout in settlements in Russia and Belarus more than two decades after the Chernobyl accident.

PubMed

Bernhardsson, C; Rääf, C L; Mattsson, S

2015-11-01

Radionuclides from the 1986 Chernobyl accident were released and dispersed during a limited period of time, but under widely varying weather conditions. As a result, there was a high geographical variation in the deposited radioactive fallout per unit area over Europe, depending on the released composition of fission products and the weather during the 10 days of releases. If the plume from Chernobyl coincided with rain, then the radionuclides were unevenly distributed on the ground. However, large variations in the initial fallout also occurred locally or even on a meter scale. Over the ensuing years the initial deposition may have been altered further by different weathering processes or human activities such as agriculture, gardening, and decontamination measures. Using measurements taken more than two decades after the accident, we report on the inhomogeneous distribution of the ground deposition of the fission product (137)Cs and its influence on the dose rate 1 m above ground, on both large and small scales (10ths of km(2) - 1 m(2)), in the Gomel-Bryansk area close to the border between Belarus and Russia. The dose rate from the deposition was observed to vary by one order of magnitude depending on the size of the area considered, whether human processes were applied to the surface or not, and on location specific properties (e.g. radionuclide migration in soil). Copyright © 2015 Elsevier Ltd. All rights reserved.

Mapping large extensions of flat dentin through digital microscopy: introduction to the method and possible applications.

PubMed

Reis, Claudia; De-Deus, Gustavo; Marins, Juliana; Fidel, Sandra; Fidel, Rivail; Paciornik, Sidnei

2012-08-01

To introduce a mapping method to characterize large dentin surfaces using digital microscopy and to discuss the advantages and possible applications of the method. Twenty unerupted third molars were sectioned transversally exposing coronal dentin surfaces. The microscopic mosaic method was used to generate a large field image with the resolution necessary to measure characteristics of dentin tubules. The AxioVision 4.7 software was used to control a motorized optical microscope and the process of acquiring approximately 400 small images to generate each dentin mosaic. An image analysis routine measured the number of tubules (NT) and the ratio between the total area of tubules and the area of the mosaic - the area fraction (AF) - of each mosaic. An automatic procedure transformed the mosaic image into a color map, providing a direct visual representation of tubule density through colors. The dentin maps were used for a comparative qualitative analysis of tubule density distribution of each sample. The results for NT (92450 to 196029 tubules/sample) and AF (4.12% to 11.10%) demonstrated a wide variation among dentin samples. The maps confirmed the microstructure variety, also revealing strong local variations in tubule density within each sample. The mapping method was able to perform dentin morphology characterization and is a valuable tool for producing a baseline for dentin adhesion studies. The method could be also useful in determining the real contribution of dentin structures to the final adhesion quality.

Evaluating Conservation Breeding Success for an Extinct-in-the-Wild Antelope.

PubMed

Little, Holly A; Gilbert, Tania C; Athorn, Marie L; Marshall, Andrew R

2016-01-01

With the number of threatened species increasing globally, conservation breeding is vitally important now more than ever. However, no previous peer-reviewed study has attempted to determine how the varying conditions across zoos have influenced breeding by an extinct-in-the-wild species. We therefore use questionnaires and studbook data to evaluate the influence of husbandry practices and enclosure design on scimitar-horned oryx (Oryx dammah) breeding success, at the herd level. Regression models were used to identify the variables that best predicted breeding success among 29 zoos across a five-year period. Calf survival decreased with herd age and the use of soft substrates in hardstand areas (yard area usually adjacent to the indoor housing), explaining 30.7% of overall variation. Calf survival also decreased where herds were small and where food provisions were not raised (and hence likely incited competition), although these were less influential. Likewise, birth rate decreased with soft substrates in hardstand areas and unraised food provisions, although these were less influential than for calf survival. Birth rate increased with year-round male presence, yet this decreased calf survival. Compared to previous studies, the number of enclosure/husbandry influences on breeding were relatively few. Nevertheless, these few enclosure/husbandry influences explained over one third of the variation in calf survival. Our data therefore suggest some potential improvements and hence that extinct-in-the-wild species stand a greater chance of survival with empirical design of zoo enclosures and husbandry methods.

Seafloor Characterization from Spatial Variation of Multibeam Backscatter vs. Grazing Angle

NASA Astrophysics Data System (ADS)

hou, T.

2001-12-01

Backscatter vs. grazing angle, which can be extracted from multibeam backscatter data, depend on characteristics of the multibeam system and the angular responses of backscatter that are characteristic of different seafloor properties, such as sediment hardness and roughness. Changes in backscatter vs. grazing angle that are contributed by the multibeam system normally remain fixed over both space and time. Therefore, they can readily be determined and removed from backscatter data. The variation of backscatter vs. grazing angle due to the properties of sediments will vary from location to location, as sediment type changes. The sediment component of variability can be inferred using the redundant observations from different grazing angles in several small pieces of seafloor where the sediment property is uniform in any given piece of seafloor yet vary from one piece of the seafloor to another. Thanks to the multibeam survey (Roger Flood, State University of New York) at SAX 99 Project sponsored by Office of Naval Research (ONR), which had 800% coverage in most of the survey area; there is a data set, which is suitable for investigating seafloor characterization. The investigation analyzed the spatial variation of the backscatter vs. grazing angle and compared that with ground truth sediment data. In this research, the 6.9 gigabytes raw multibeam data were cleaned using an automated outlier detection algorithm (Tianhang Hou, Lloyd Huff and Larry Mayer. 2001). Then, the surveyed area was equally divided into 52X78 rectangle working cells (4056), the side of each cell was about 20 meters. The backscatter vs. grazing angle of backscatter data for each cell is computed by averaging backscatter data by the corresponding beam numbers using all data with the same beam number from different survey lines. Systematic effects on the backscatter vs. grazing angle, caused by multibeam system hardware or software as well as system installation, were corrected in order to remove the asymmetric and skew effects. In order to easily evaluate the spatial variation of the backscatter vs. grazing angle, a graphic interface was developed. With a mouse click, the images based on different subsets of the data can be compared throughout the survey area. The subsets were created using specific beam numbers. These images for different beams show significant variations between nadir and off-nadir beams. These variations allow an interesting interpretation to be made of the images in light of seafloor characteristics, which were derived from ground truth data, such as sediment grain size, density and velocity.

Extreme throat initial data set and horizon area-angular momentum inequality for axisymmetric black holes

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

Dain, Sergio; Max Planck Institute for Gravitational Physics

2010-11-15

We present a formula that relates the variations of the area of extreme throat initial data with the variation of an appropriate defined mass functional. From this expression we deduce that the first variation, with fixed angular momentum, of the area is zero and the second variation is positive definite evaluated at the extreme Kerr throat initial data. This indicates that the area of the extreme Kerr throat initial data is a minimum among this class of data. And hence the area of generic throat initial data is bounded from below by the angular momentum. Also, this result strongly suggestsmore » that the inequality between area and angular momentum holds for generic asymptotically flat axially symmetric black holes. As an application, we prove this inequality in the nontrivial family of spinning Bowen-York initial data.« less

Divergent drivers of the spatial and temporal variations of cropland carbon transfer in Liaoning province, China.

PubMed

Zhu, Xian-Jin; Zhang, Han-Qi; Zhao, Tian-Hong; Li, Jian-Dong; Yin, Hong

2017-10-12

Spatial and temporal variations are important points of focus in ecological research. Analysing their differences improves our understanding on the variations of ecological phenomena. Using data from the Liaoning Statistical Yearbook, we investigated the spatial and temporal variations of cropland carbon transfer (CCT), an important ecological phenomenon in quantifying the regional carbon budget, in particular, the influencing factors and difference. The results showed that, from 1992 to 2014, the average CCT in Liaoning province was 18.56 TgC yr -1 and decreased from northwest to southeast. CCT spatial variation was primarily affected by the ratio of planting area to regional area (RPR) via its effect on the magnitude of carbon transfer (MCT), which depended mainly on fertilizer usage per area (FUA). From 1992 to 2014, CCT exhibited a significantly increasing trend with a rate of 0.48 TgC yr -1 . The inter-annual variation of CCT was dominated by carbon transfer per planting area (CTP) through its effect on MCT, which significantly correlated with FUA but showed no significant correlation with climatic factors. Therefore, the factors affecting the spatial variation of CCT differed from those that affected its inter-annual variation, indicating that the spatial and temporal variations of ecological phenomena were affected by divergent factors.

Nanometre-scale thermometry in a living cell

NASA Astrophysics Data System (ADS)

Kucsko, G.; Maurer, P. C.; Yao, N. Y.; Kubo, M.; Noh, H. J.; Lo, P. K.; Park, H.; Lukin, M. D.

2013-08-01

Sensitive probing of temperature variations on nanometre scales is an outstanding challenge in many areas of modern science and technology. In particular, a thermometer capable of subdegree temperature resolution over a large range of temperatures as well as integration within a living system could provide a powerful new tool in many areas of biological, physical and chemical research. Possibilities range from the temperature-induced control of gene expression and tumour metabolism to the cell-selective treatment of disease and the study of heat dissipation in integrated circuits. By combining local light-induced heat sources with sensitive nanoscale thermometry, it may also be possible to engineer biological processes at the subcellular level. Here we demonstrate a new approach to nanoscale thermometry that uses coherent manipulation of the electronic spin associated with nitrogen-vacancy colour centres in diamond. Our technique makes it possible to detect temperature variations as small as 1.8 mK (a sensitivity of 9 mK Hz-1/2) in an ultrapure bulk diamond sample. Using nitrogen-vacancy centres in diamond nanocrystals (nanodiamonds), we directly measure the local thermal environment on length scales as short as 200 nanometres. Finally, by introducing both nanodiamonds and gold nanoparticles into a single human embryonic fibroblast, we demonstrate temperature-gradient control and mapping at the subcellular level, enabling unique potential applications in life sciences.

Aging and domain growth in K1-xLixTaO3 (x<=0.05)

NASA Astrophysics Data System (ADS)

Alberici-Kious, F.; Bouchaud, J.-P.; Cugliandolo, L. F.; Doussineau, P.; Levelut, A.

2000-12-01

We present experimental results on the dielectric constant in orientational glasses K1-xLixTaO3 (KLT) with x<=0.05, together with the detailed (analytic and numerical) study of a model which attributes the observed aging to the motion of the walls of polarization domains. We show that the dielectric constant after a positive temperature jump goes through a maximum as a function of the subsequent time. This observation and those previously reported (aging, cooling rate dependence, etc.) are compared with the predictions of the model, in which the variations of the dielectric constant are attributed to the change of polarization domain wall area. The total area decreases by domain growth and increases by nucleation of new small domains inside the larger ones. These two opposite variations are both hindered by static random fields (equivalent to energy barriers) due to the frozen dipoles borne by the off-center Li+ ions. Many results are well explained by the model with a single energy barrier. However, some effects can only be understood if a broad distribution of energy barriers is assumed. We use the experimental data to determine this distribution and find it to be unimodal with a width comparable to its most probable value.

Surface area-volume ratios in insects.

PubMed

Kühsel, Sara; Brückner, Adrian; Schmelzle, Sebastian; Heethoff, Michael; Blüthgen, Nico

2017-10-01

Body mass, volume and surface area are important for many aspects of the physiology and performance of species. Whereas body mass scaling received a lot of attention in the literature, surface areas of animals have not been measured explicitly in this context. We quantified surface area-volume (SA/V) ratios for the first time using 3D surface models based on a structured light scanning method for 126 species of pollinating insects from 4 orders (Diptera, Hymenoptera, Lepidoptera, and Coleoptera). Water loss of 67 species was measured gravimetrically at very dry conditions for 2 h at 15 and 30 °C to demonstrate the applicability of the new 3D surface measurements and relevance for predicting the performance of insects. Quantified SA/V ratios significantly explained the variation in water loss across species, both directly or after accounting for isometric scaling (residuals of the SA/V ∼ mass 2/3 relationship). Small insects with a proportionally larger surface area had the highest water loss rates. Surface scans of insects to quantify allometric SA/V ratios thus provide a promising method to predict physiological responses, improving the potential of body mass isometry alone that assume geometric similarity. © 2016 Institute of Zoology, Chinese Academy of Sciences.

Spatial characteristics of the tropical cloud systems: comparison between model simulation and satellite observations

NASA Astrophysics Data System (ADS)

Zhang, Guang J.; Zurovac-Jevtic, Dance; Boer, Erwin R.

1999-10-01

A Lagrangian cloud classification algorithm is applied to the cloud fields in the tropical Pacific simulated by a high-resolution regional atmospheric model. The purpose of this work is to assess the model's ability to reproduce the observed spatial characteristics of the tropical cloud systems. The cloud systems are broadly grouped into three categories: deep clouds, mid-level clouds and low clouds. The deep clouds are further divided into mesoscale convective systems and nonmesoscale convective systems. It is shown that the model is able to simulate the total cloud cover for each category reasonably well. However, when the cloud cover is broken down into contributions from cloud systems of different sizes, it is shown that the simulated cloud size distribution is biased toward large cloud systems, with contribution from relatively small cloud systems significantly under-represented in the model for both deep and mid-level clouds. The number distribution and area contribution to the cloud cover from mesoscale convective systems are very well simulated compared to the satellite observations, so are low clouds as well. The dependence of the cloud physical properties on cloud scale is examined. It is found that cloud liquid water path, rainfall, and ocean surface sensible and latent heat fluxes have a clear dependence on cloud types and scale. This is of particular interest to studies of the cloud effects on surface energy budget and hydrological cycle. The diurnal variation of the cloud population and area is also examined. The model exhibits a varying degree of success in simulating the diurnal variation of the cloud number and area. The observed early morning maximum cloud cover in deep convective cloud systems is qualitatively simulated. However, the afternoon secondary maximum is missing in the model simulation. The diurnal variation of the tropospheric temperature is well reproduced by the model while simulation of the diurnal variation of the moisture field is poor. The implication of this comparison between model simulation and observations on cloud parameterization is discussed.

Quantifying the forcing effect of channel width variations on free bars: Morphodynamic modeling based on characteristic dissipative Galerkin scheme

NASA Astrophysics Data System (ADS)

Wu, Fu-Chun; Shao, Yun-Chuan; Chen, Yu-Chen

2011-09-01

The forcing effect of channel width variations on free bars is investigated in this study using a two-dimensional depth-averaged morphodynamic model. The novel feature of the model is the incorporation of a characteristic dissipative Galerkin (CDG) upwinding scheme in the bed evolution module. A correction for the secondary flows induced by streamline curvature is also included, allowing for simulations of bar growth and migration in channels with width variations beyond the small-amplitude regimes. The model is tested against a variety of experimental data ranging from purely forced and free bars to coexisting bed forms in the variable-width channel. The CDG scheme effectively dissipates local bed oscillations, thus sustains numerical stabilities. The results show that the global effect of width variations on bar height is invariably suppressive. Such effect increases with the dimensionless amplitude AC and wave number λC of width variations. For small AC, λC has little effects on bar height; for AC beyond small amplitudes, however, the suppressing effect depends on both AC and λC. The suppressing effect on bar length increases also with both AC and λC, but is much weaker than that on bar height. The global effect of width variations on bar celerity can be suppressive or enhancive, depending on the combination of AC and λC. For smaller λC, the effect on bar celerity is enhancive; for larger λC, bar celerity tends to increase at small AC but decreases for AC beyond small amplitudes. We present herein an unprecedented data set verifying the theoretical prediction on celerity enhancement. Full suppression of bar growth above the theoretically predicted threshold AC was not observed, regardless of the adopted amplitude of initial bed perturbation A. The global effects of width variations on free bars can be quantified using a forcing factor FC that integrates the effects of AC and λC. The suppressing effects on bar height and length are both proportional to FC2.16; the global effect on bar celerity is, however, a parabolic function of FC.

A review of geographic variation and Geographic Information Systems (GIS) applications in prescription drug use research.

PubMed

Wangia, Victoria; Shireman, Theresa I

2013-01-01

While understanding geography's role in healthcare has been an area of research for over 40 years, the application of geography-based analyses to prescription medication use is limited. The body of literature was reviewed to assess the current state of such studies to demonstrate the scale and scope of projects in order to highlight potential research opportunities. To review systematically how researchers have applied geography-based analyses to medication use data. Empiric, English language research articles were identified through PubMed and bibliographies. Original research articles were independently reviewed as to the medications or classes studied, data sources, measures of medication exposure, geographic units of analysis, geospatial measures, and statistical approaches. From 145 publications matching key search terms, forty publications met the inclusion criteria. Cardiovascular and psychotropic classes accounted for the largest proportion of studies. Prescription drug claims were the primary source, and medication exposure was frequently captured as period prevalence. Medication exposure was documented across a variety of geopolitical units such as countries, provinces, regions, states, and postal codes. Most results were descriptive and formal statistical modeling capitalizing on geospatial techniques was rare. Despite the extensive research on small area variation analysis in healthcare, there are a limited number of studies that have examined geographic variation in medication use. Clearly, there is opportunity to collaborate with geographers and GIS professionals to harness the power of GIS technologies and to strengthen future medication studies by applying more robust geospatial statistical methods. Copyright © 2013 Elsevier Inc. All rights reserved.

Variations in trace element geochemistry in the Seine River Basin based on floodplain deposits and bed sediments

USGS Publications Warehouse

Horowitz, A.J.; Meybeck, Michel; Idlafkih, Z.; Biger, E.

1999-01-01

Between 1990 and 1995 a series of bed sediment, suspended sediment and fresh floodplain samples were collected within the Seine River Basin, in France, to evaluate variations in trace element geochemistry. Average background trace element levels for the basin were determined from the collection and subsequent analyses of bed sediment samples from small rural watersheds and from a prehistoric (5000 BP) site in Paris. Concentrations are relatively low, and similar to those observed for fine-grained bed sediments from unaffected areas in the United States and Canada. However, the concentrations are somewhat higher than the reference levels presently adopted by French water authorities for areas north of the Seine Basin, which have similar bedrock lithologies. Downstream trace element variations were monitored in 1994 and 1995 using fresh surficial floodplain samples that were collected either as dried deposits a few days after peak discharge, or immediately after peak discharge (under ??? 30 cm of water). Chemical comparisons between fresh floodplain deposits, and actual suspended sediments collected during flood events, indicate that, with some caveats, the former can be used as surrogates for the latter. The floodplain sediment chemical data indicate that within the Seine Basin, from the relatively unaffected headwaters through heavily affected urban streams, trace element concentrations vary by as much as three orders of magnitude. These trace element changes appear to be the result of both increases in population as well as concomitant increases in industrial activity. This article is a US government work and is in the public domain in the United States.

Longitudinal trends and subgroup analysis in publication patterns for preclinical data of newly approved drugs.

PubMed

Köster, Ursula; Nolte, Ingo; Michel, Martin C

2016-02-01

Having observed a large variation in the number and type of original preclinical publications for newly registered drugs, we have explored whether longitudinal trends and/or factors specific for certain drugs or their manufacturers may explain such variation. Our analysis is based on 1954 articles related to 170 newly approved drugs. The number of preclinical publications per compound declined from a median of 10.5 in 1991 to 3 in 2011. A similar trend was observed for the number of in vivo studies in general, but not in the subset of in vivo studies in animal models of disease. The percentage of compounds with studies using isolated human cells or cell lines almost doubled over time from 37 to 72%. Number of publications did not exhibit major differences between compounds intended for human versus veterinary use, therapeutic areas, small molecules versus biologicals, or innovator versus follow-up compounds; however, some companies may publish fewer studies per compound than others. However, there were qualitative differences in the types of models being used depending on the therapeutic area; specifically, compounds for use in oncology very often used isolated cells and cell lines, often from human origin. We conclude that the large variation in number and type of reported preclinical data is not easily explained. We propose that pharmaceutical companies should consistently provide a comprehensive documentation of the preclinical data they generate as part of their development programs in the public domain to enable a better understanding of the drugs they intend to market.

Genetic Structure in a Small Pelagic Fish Coincides with a Marine Protected Area: Seascape Genetics in Patagonian Fjords.

PubMed

Canales-Aguirre, Cristian B; Ferrada-Fuentes, Sandra; Galleguillos, Ricardo; Hernández, Cristián E

2016-01-01

Marine environmental variables can play an important role in promoting population genetic differentiation in marine organisms. Although fjord ecosystems have attracted much attention due to the great oscillation of environmental variables that produce heterogeneous habitats, species inhabiting this kind of ecosystem have received less attention. In this study, we used Sprattus fuegensis, a small pelagic species that populates the inner waters of the continental shelf, channels and fjords of Chilean Patagonia and Argentina, as a model species to test whether environmental variables of fjords relate to population genetic structure. A total of 282 individuals were analyzed from Chilean Patagonia with eight microsatellite loci. Bayesian and non-Bayesian analyses were conducted to describe the genetic variability of S. fuegensis and whether it shows spatial genetic structure. Results showed two well-differentiated genetic clusters along the Chilean Patagonia distribution (i.e. inside the embayment area called TicToc, and the rest of the fjords), but no spatial isolation by distance (IBD) pattern was found with a Mantel test analysis. Temperature and nitrate were correlated to the expected heterozygosities and explained the allelic frequency variation of data in the redundancy analyses. These results suggest that the singular genetic differences found in S. fuegensis from inside TicToc Bay (East of the Corcovado Gulf) are the result of larvae retention bya combination of oceanographic mesoscale processes (i.e. the west wind drift current reaches the continental shelf exactly in this zone), and the local geographical configuration (i.e. embayment area, islands, archipelagos). We propose that these features generated an isolated area in the Patagonian fjords that promoted genetic differentiation by drift and a singular biodiversity, adding support to the existence of the largest marine protected area (MPA) of continental Chile, which is the Tic-Toc MPA.

Explanatory models concerning the effects of small-area characteristics on individual health.

PubMed

Voigtländer, Sven; Vogt, Verena; Mielck, Andreas; Razum, Oliver

2014-06-01

Material and social living conditions at the small-area level are assumed to have an effect on individual health. We review existing explanatory models concerning the effects of small-area characteristics on health and describe the gaps future research should try to fill. Systematic literature search for, and analysis of, studies that propose an explanatory model of the relationship between small-area characteristics and health. Fourteen studies met our inclusion criteria. Using various theoretical approaches, almost all of the models are based on a three-tier structure linking social inequalities (posited at the macro-level), small-area characteristics (posited at the meso-level) and individual health (micro-level). No study explicitly defines the geographical borders of the small-area context. The health impact of the small-area characteristics is explained by specific pathways involving mediating factors (psychological, behavioural, biological). These pathways tend to be seen as uni-directional; often, causality is implied. They may be modified by individual factors. A number of issues need more attention in research on explanatory models concerning small-area effects on health. Among them are the (geographical) definition of the small-area context; the systematic description of pathways comprising small-area contextual as well as compositional factors; questions of direction of association and causality; and the integration of a time dimension.

Mechanism of Muong Nong-type tektite formation and speculation on the source of Australasian tektites

NASA Technical Reports Server (NTRS)

Schnetzler, C. C.

1992-01-01

The source crater of the youngest and largest of the tektite strewnfields, the Australasian strewnfield, has not been located. A number of lines of evidence indicate that the Muong Nong-type tektites, primarily found in Indochina, are more primitive than the much more abundant and widespread splash-form tektites, and are proximal to the source. In this study the spatial distribution of Muong Nong-type tektite sites and chemical character have been used to indicate the approximate location of the source. The variation of Muong Nong-type tektite chemical composition appears to be caused by mixing of two silicate rock end-members and a small amount of limestone, and not by vapor fractionation. The variation in composition is not random, and does not support in situ melting or multiple impact theories. The distribution of both Muong Nong and splash-form tektite sites suggest the source is in a limited area near the southern part of the Thailand-Laos border.

Spatial and temporal variation of macro-, meso- and microplastic abundance on a remote coral island of the Maldives, Indian Ocean.

PubMed

Imhof, Hannes K; Sigl, Robert; Brauer, Emilia; Feyl, Sabine; Giesemann, Philipp; Klink, Saskia; Leupolz, Kathrin; Löder, Martin G J; Löschel, Lena A; Missun, Jan; Muszynski, Sarah; Ramsperger, Anja F R M; Schrank, Isabella; Speck, Susan; Steibl, Sebastian; Trotter, Benjamin; Winter, Isabel; Laforsch, Christian

2017-03-15

Plastic debris is ubiquitous in the marine environment and the world's shores represent a major sink. However, knowledge about plastic abundance in remote areas is scarce. Therefore, plastic abundance was investigated on a small island of the Maldives. Plastic debris (>1mm) was sampled once in natural long-term accumulation zones at the north shore and at the high tide drift line of the south shore on seven consecutive days to quantify daily plastic accumulation. Reliable identification of plastic debris was ensured by FTIR spectroscopy. Despite the remoteness of the island a considerable amount of plastic debris was present. At both sites a high variability in plastic abundance on a spatial and temporal scale was observed, which may be best explained by environmental factors. In addition, our results show that snapshot sampling may deliver biased results and indicate that future monitoring programs should consider spatial and temporal variation of plastic deposition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oxygen isotope variations in phosphate of deer bones

NASA Astrophysics Data System (ADS)

Luz, Boaz; Cormie, Allison B.; Schwarcz, Henry P.

1990-06-01

Variations of δ 18O of bone phosphate (δ p) of white tailed deer were studied in samples with wide geographic distribution in North America. Bones from the same locality have similar isotopic values, and the difference between specimens (0.4‰) is not large relative to the measurement error (0.3‰). The total range of δ p values is about 12‰. This indicates that deer use water from a relatively small area, and thus their δ p indicates local environmental conditions. Multiple regression analysis between oxygen isotope composition of deer bone phosphate and of local relative humidity and precipitation (δ w) yields a high correlation coefficient (0.95). This correlation is significantly better than the linear correlation (0.81) between δ p and δ w of precipitation alone. Thus δ p depends on both isotopic composition of precipitation and on relative humidity. This is because deer obtain most of their water from leaves, the isotopic composition of which is partly controlled by relative humidity through evaporation/transpiration.

Fine-scale analysis of genetic structure in the brooding coral Seriatopora hystrix from the Red Sea

NASA Astrophysics Data System (ADS)

Maier, E.; Tollrian, R.; Nürnberger, B.

2009-09-01

The dispersal of gametes and larvae plays a key role in the population dynamics of sessile marine invertebrates. Species with internal fertilisation are often associated with very localised larval dispersal, which may cause small-scale patterns of neutral genetic variation. This study on the brooding coral Seriatopora hystrix from the Red Sea focused on the smallest possible scale: Two S. hystrix stands (~100 colonies each) near Dahab were completely sampled, mapped and analysed at five microsatellite markers. The sexual mode of reproduction, the likely occurrence of selfing and the level of immigration were in agreement with previous studies on this species. Contrary to previous findings, both stands were in Hardy-Weinberg proportions. Also, no evidence for spatially restricted larval dispersal within the sampled areas was found. Differences between this and previous studies on S. hystrix could reflect variation in life history or varying environmental conditions, which opens intriguing questions for future research.

Establishing a baseline: the amphibians of Lower Suwannee National Wildlife Refuge, Dixie and Levy counties, Florida

USGS Publications Warehouse

Dodd, C. Kenneth; Barichivich, William J.; Johnson, Steve A.; Gunzburger Aresco, Margaret; Staiger, Jennifer S.

2018-01-01

recorded 23 amphibian species, 19 frogs and 4 salamanders. Species richness was lower than in other areas of the coastal Big Bend region to the north, perhaps due to a combination of proximity to the limits of species’ ranges, sampling techniques, times of year when sampling occurred, and variation in detection probabilities among years and regions. Amphibians occupied a wide variety of habitats and appeared tolerant of the generally acidic conditions of many of the wetlands. Small streams and the Suwannee River were less acidic and had greater conductivities and mineral concentrations than isolated ponds; concentrations of heavy metals varied and mercury was not detected. Although additional species may yet be found in LSNWR, this survey provides a historic baseline for assessing future status and trends of amphibian populations as areas adjacent to the refuge are disturbed and as restoration and multi-use management continue within its boundaries.

Modeling the Exo-Brake and the Development of Strategies for De-Orbit Drag Modulation

NASA Technical Reports Server (NTRS)

Murbach, M. S.; Papadopoulos, P.; Glass, C.; Dwyer-Cianciolo, A.; Powell, R. W.; Dutta, S.; Guarneros-Luna, A.; Tanner, F. A.; Dono, A.

2016-01-01

The Exo-Brake is a simple, non-propulsive means of de-orbiting small payloads from orbital platforms such as the International Space Station (ISS). Two de-orbiting experiments with fixed surface area Exo-Brakes have been successfully conducted in the last two years on the TechEdSat-3 and -4 nano-satellite missions. The development of the free molecular flow aerodynamic data-base is presented in terms of angle of attack, projected front surface area variation, and altitude. Altitudes are considered ranging from the 400km ISS jettison altitude to 90km. Trajectory tools are then used to predict de-orbit/entry corridors with the inclusion of the key atmospheric and geomagnetic uncertainties. Control system strategies are discussed which will be applied to the next two planned TechEdSat-5 and -6 nano-satellite missions - thus increasing the targeting accuracy at the Von Karman altitude through the proposed drag modulation technique.

Epiphytic lichen diversity on dead and dying conifers under different levels of atmospheric pollution.

PubMed

Hauck, Markus

2005-05-01

Based on literature data, epiphytic lichen abundance was comparably studied in montane woodlands on healthy versus dead or dying conifers of Europe and North America in areas with different levels of atmospheric pollution. Study sites comprised Picea abies forests in the Harz Mountains and in the northern Alps, Germany, Picea rubens-Abies balsamea forests on Whiteface Mountain, Adirondacks, New York, U.S.A. and Picea engelmannii-Abies lasiocarpa forests in the Salish Mountains, Montana, U.S.A. Detrended correspondence analysis showed that epiphytic lichen vegetation differed more between healthy and dead or dying trees at high- versus low-polluted sites. This is attributed to greater differences in chemical habitat conditions between trees of different vitality in highly polluted areas. Based on these results, a hypothetical model of relative importance of site factors for small-scale variation of epiphytic lichen abundance versus atmospheric pollutant load is discussed.

Source characterization of a small earthquake cluster at Edmond, Oklahoma using a very dense array

NASA Astrophysics Data System (ADS)

Ng, R.; Nakata, N.

2017-12-01

Recent seismicity in Oklahoma has caught the attention of the public in the last few years since seismicity is commonly related to loss in urban areas. To account for the increase in public interest, improve the understanding of damaging ground motions produced in earthquakes and develop better seismic hazard assessment, we must characterize the seismicity in Oklahoma and its associated structure and source parameters. Regional changes in subsurface stresses have increased seismic activities due to reactivation of faults in places such as central Oklahoma. It is imperative for seismic investigation and modeling to characterize subsurface structural features that may influence the damaging effects of ground motion. We analyze the full-waveform data collected from a temporary dense array of 72 portable seismometers with a 110 meter spacing that were active for a one-month period from May to June 2017, deployed at Edmond, Oklahoma. The data from this one-month duration array captured over 10,000 events and enabled us to make measurements of small-scale lateral variations of earthquake wavefields. We examine the waveform for events using advanced methods of detection, location and determine the source mechanism. We compare our results with selected events listed in the Oklahoma Geological Survey (OGS) and United States Geological Survey (USGS) catalogue. Based on the detection and located small events, we will discuss the causative fault structure at the area and present the results of the investigation.

Differences in seed rain composition in small and large fragments in the northeast Brazilian Atlantic Forest.

PubMed

Knörr, U C; Gottsberger, G

2012-09-01

Tropical forests are seriously threatened by fragmentation and habitat loss. The impact of fragment size and forest configuration on the composition of seed rain is insufficiently studied. For the present study, seed rain composition of small and large forest fragments (8-388 ha) was assessed in order to identify variations in seed abundance, species richness, seed size and dispersal mode. Seed rain was documented during a 1-year period in three large and four small Atlantic Forest fragments that are isolated by a sugarcane matrix. Total seed rain included 20,518 seeds of 149 species of trees, shrubs, palms, lianas and herbs. Most species and seeds were animal-dispersed. A significant difference in the proportion of seeds and species within different categories of seed size was found between small and large fragments. Small fragments received significantly more very small-sized seeds (<0.3 cm) and less large-seeded species (>1.5 cm) that were generally very rare, with only one species in small and eight in large fragments. We found a negative correlation between the inflow of small-sized seeds and the percentage of forest cover. Species richness was lower in small than in large fragments, but the difference was not very pronounced. Given our results, we propose changing plant species pools through logging, tree mortality and a high inflow of pioneer species and lianas, especially in small forest fragments and areas with low forest cover. Connecting forest fragments through corridors and reforestation with local large-seeded tree species may facilitate the maintenance of species diversity. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

12 CFR 25.22 - Lending test.

Code of Federal Regulations, 2013 CFR

2013-01-01

... assessment area(s) through its lending activities by considering a bank's home mortgage, small business... mortgage, small business, small farm, and consumer loans, if applicable, in the bank's assessment area(s); (2) Geographic distribution. The geographic distribution of the bank's home mortgage, small business...

12 CFR 25.22 - Lending test.

Code of Federal Regulations, 2011 CFR

2011-01-01

... assessment area(s) through its lending activities by considering a bank's home mortgage, small business... mortgage, small business, small farm, and consumer loans, if applicable, in the bank's assessment area(s); (2) Geographic distribution. The geographic distribution of the bank's home mortgage, small business...

12 CFR 25.22 - Lending test.

Code of Federal Regulations, 2014 CFR

2014-01-01

... assessment area(s) through its lending activities by considering a bank's home mortgage, small business... mortgage, small business, small farm, and consumer loans, if applicable, in the bank's assessment area(s); (2) Geographic distribution. The geographic distribution of the bank's home mortgage, small business...

Are Solar Activity Variations Amplified by the QBO: A Modeling Study

NASA Technical Reports Server (NTRS)

Mengel, J. G.; Mayr, H. G.; Drob, D. P.; Porter, H. S.; Bhartia, P. K. (Technical Monitor)

2002-01-01

Solar cycle activity effects (SCAE) in the lower and middle atmosphere, reported in several studies, are difficult to explain on the basis of the small changes in solar radiation that accompany the 11-year cycle. It is therefore natural to speculate that dynamical processes may come into play to produce a leverage. Such a leverage may be provided by the Quasi-Biennial Oscillation (QBO) in the zonal circulation of the stratosphere, which has been linked to solar activity variations. Driven primarily by wave mean flow interaction, the QBO period and its amplitude are variable but are also strongly influenced by the seasonal cycle in the solar radiation. This influence extends to low altitudes and is referred to as 'downward control'. Small changes in the solar radiative forcing may produce small changes in the period and phase of the QBO, but these in turn may produce measurable differences in the wind field. Thus, the QBO may be an amplifier of solar activity variations and a natural conduit of these variations to lower altitudes. To test this hypothesis, we conducted experiments with a 2D version of our Numerical Spectral Model that incorporates Hines' Doppler Spread Parameterization for small-scale gravity waves (GW). Solar cycle radiance variations (SCRV) are accounted for by changing the radiative heating rate on a logarithmic scale from 0.1% at the surface to 1% at 50 km to 10% at 100 km. With and without SCRV, but with the same GW flux, we then conduct numerical experiments to evaluate the magnitude of the SCAE in the zonal circulation. The numerical results indicate that, under certain conditions, the SCAE is significant and can extend to lower altitudes where the SCRV is small. For a modeled QBO period of 30 months, we find that the seasonal cycle in the solar forcing acts as a strong pacemaker to lock up the phase and period of the QBO. The SCAE then shows up primarily as a distinct but relatively weak amplitude modulation. But with a different QBO period between 30 and 34 (or less than 30, presumably) months, the seasonal phase lock is weak. Solar flux variations in the seasonal cycle then cause variations in the QBO period and phase. These amplify the SCAE to produce relatively large variations in the wind field. The SCAE in this case extends to mid-latitudes.

Spatial variability of nutrients (N, P) in a deep, temperate lake with a low trophic level supported by global navigation satellite systems, geographic information system and geostatistics.

PubMed

Łopata, Michał; Popielarczyk, Dariusz; Templin, Tomasz; Dunalska, Julita; Wiśniewski, Grzegorz; Bigaj, Izabela; Szymański, Daniel

2014-01-01

We investigated changes in the spatial distribution of phosphorus (P) and nitrogen (N) in the deep, mesotrophic Lake Hańcza. The raw data collection, supported by global navigation satellite system (GNSS) positioning, was conducted on 79 sampling points. A geostatistical method (kriging) was applied in spatial interpolation. Despite the relatively small area of the lake (3.04 km(2)), compact shape (shore development index of 2.04) and low horizontal exchange of water (retention time 11.4 years), chemical gradients in the surface waters were found. The largest variation concerns the main biogenic element - phosphorus. The average value was 0.032 at the extreme values of 0.019 to 0.265 mg L(-1) (coefficient of variation 87%). Smaller differences are related to nitrogen compounds (0.452-1.424 mg L(-1) with an average value of 0.583 mg L(-1), the coefficient of variation 20%). The parts of the lake which are fed with tributaries are the richest in phosphorus. The water quality of the oligo-mesotrophic Lake Hańcza has been deteriorating in recent years. Our results indicate that inferences about trends in the evolution of examined lake trophic status should be based on an analysis of the data, taking into account the local variation in water chemistry.

Genetic diversity and population structure of an extremely endangered species: the world's largest Rhododendron.

PubMed

Wu, Fu Qin; Shen, Shi Kang; Zhang, Xin Jun; Wang, Yue Hua; Sun, Wei Bang

2014-12-04

Comprehensive studies on the genetic diversity and structure of endangered species are urgently needed to promote effective conservation and management activities. The big tree rhododendron, Rhododendron protistum var. giganteum, is a highly endangered species with only two known endemic populations in a small area in the southern part of Yunnan Province in China. Unfortunately, limited information is available regarding the population genetics of this species. Therefore, we conducted amplified fragment length polymorphism (AFLP) analysis to characterize the genetic diversity and variation of this species within and between remaining populations. Twelve primer combinations of AFLP produced 447 unambiguous and repetitious bands. Among these bands, 298 (66.67 %) were polymorphic. We found high genetic diversity at the species level (percentage of polymorphic loci = 66.67 %, h = 0.240, I = 0.358) and low genetic differentiation (Gst = 0.110) between the two populations. Gene flow between populations (Nm) was relatively high at 4.065. Analysis of molecular variance results revealed that 22 % of the genetic variation was partitioned between populations and 78 % of the genetic variation was within populations. The presence of moderate to high genetic diversity and low genetic differentiation in the two populations can be explained by life history traits, pollen dispersal and high gene flow (Nm = 4.065). Bayesian structure and principal coordinate analysis revealed that 56 sampled trees were clustered into two groups. Our results suggest that some rare and endangered species are able to maintain high levels of genetic diversity even at small population sizes. These results will assist with the design of conservation and management programmes, such as in situ and ex situ conservation, seed collection for germplasm conservation and reintroduction. Published by Oxford University Press on behalf of the Annals of Botany Company.

Is earthquake rate in south Iceland modified by seasonal loading?

NASA Astrophysics Data System (ADS)

Jonsson, S.; Aoki, Y.; Drouin, V.

2017-12-01

Several temporarily varying processes have the potential of modifying the rate of earthquakes in the south Iceland seismic zone, one of the two most active seismic zones in Iceland. These include solid earth tides, seasonal meteorological effects and influence from passing weather systems, and variations in snow and glacier loads. In this study we investigate the influence these processes may have on crustal stresses and stressing rates in the seismic zone and assess whether they appear to be influencing the earthquake rate. While historical earthquakes in the south Iceland have preferentially occurred in early summer, this tendency is less clear for small earthquakes. The local earthquake catalogue (going back to 1991, magnitude of completeness < 1.0) has indeed more earthquakes in summer than in winter. However, this pattern is strongly influenced by aftershock sequences of the largest M6+ earthquakes, which occurred in June 2000 and May 2008. Standard Reasenberg earthquake declustering or more involved model independent stochastic declustering algorithms are not capable of fully eliminating the aftershocks from the catalogue. We therefore inspected the catalogue for the time period before 2000 and it shows limited seasonal tendency in earthquake occurrence. Our preliminary results show no clear correlation between earthquake rates and short-term stressing variations induced from solid earth tides or passing storms. Seasonal meteorological effects also appear to be too small to influence the earthquake activity. Snow and glacier load variations induce significant vertical motions in the area with peak loading occurring in Spring (April-May) and maximum unloading in Fall (Sept.-Oct.). Early summer occurrence of historical earthquakes therefore correlates with early unloading rather than with the peak unloading or unloading rate, which appears to indicate limited influence of this seasonal process on the earthquake activity.

Mapping irrigated areas of Ghana using fusion of 30 m and 250 m resolution remote-sensing data

USGS Publications Warehouse

Gumma, M.K.; Thenkabail, P.S.; Hideto, F.; Nelson, A.; Dheeravath, V.; Busia, D.; Rala, A.

2011-01-01

Maps of irrigated areas are essential for Ghana's agricultural development. The goal of this research was to map irrigated agricultural areas and explain methods and protocols using remote sensing. Landsat Enhanced Thematic Mapper (ETM+) data and time-series Moderate Resolution Imaging Spectroradiometer (MODIS) data were used to map irrigated agricultural areas as well as other land use/land cover (LULC) classes, for Ghana. Temporal variations in the normalized difference vegetation index (NDVI) pattern obtained in the LULC class were used to identify irrigated and non-irrigated areas. First, the temporal variations in NDVI pattern were found to be more consistent in long-duration irrigated crops than with short-duration rainfed crops due to more assured water supply for irrigated areas. Second, surface water availability for irrigated areas is dependent on shallow dug-wells (on river banks) and dug-outs (in river bottoms) that affect the timing of crop sowing and growth stages, which was in turn reflected in the seasonal NDVI pattern. A decision tree approach using Landsat 30 m one time data fusion with MODIS 250 m time-series data was adopted to classify, group, and label classes. Finally, classes were tested and verified using ground truth data and national statistics. Fuzzy classification accuracy assessment for the irrigated classes varied between 67 and 93%. An irrigated area derived from remote sensing (32,421 ha) was 20-57% higher than irrigated areas reported by Ghana's Irrigation Development Authority (GIDA). This was because of the uncertainties involved in factors such as: (a) absence of shallow irrigated area statistics in GIDA statistics, (b) non-clarity in the irrigated areas in its use, under-development, and potential for development in GIDA statistics, (c) errors of omissions and commissions in the remote sensing approach, and (d) comparison involving widely varying data types, methods, and approaches used in determining irrigated area statistics using GIDA and remote sensing. Extensive field campaigns to help in better classification and validation of irrigated areas using high (30 m ) to very high (<5 m) resolution remote sensing data that are fused with multi temporal data like MODIS are the way forward. This is especially true in accounting for small yet contiguous patches of irrigated areas from dug-wells and dug-outs. ?? 2011 by the authors.

Irregular topography at the Earth’s inner core boundary

PubMed Central

Dai, Zhiyang; Wang, Wei; Wen, Lianxing

2012-01-01

Compressional seismic wave reflected off the Earth’s inner core boundary (ICB) from earthquakes occurring in the Banda Sea and recorded at the Hi-net stations in Japan exhibits significant variations in travel time (from -2 to 2.5 s) and amplitude (with a factor of more than 4) across the seismic array. Such variations indicate that Earth’s ICB is irregular, with a combination of at least two scales of topography: a height variation of 14 km changing within a lateral distance of no more than 6 km, and a height variation of 4–8 km with a lateral length scale of 2–4 km. The characteristics of the ICB topography indicate that small-scale variations of temperature and/or core composition exist near the ICB, and/or the ICB topographic surface is being deformed by small-scale forces out of its thermocompositional equilibrium position and is metastable. PMID:22547788

Irregular topography at the Earth's inner core boundary.

PubMed

Dai, Zhiyang; Wang, Wei; Wen, Lianxing

2012-05-15

Compressional seismic wave reflected off the Earth's inner core boundary (ICB) from earthquakes occurring in the Banda Sea and recorded at the Hi-net stations in Japan exhibits significant variations in travel time (from -2 to 2.5 s) and amplitude (with a factor of more than 4) across the seismic array. Such variations indicate that Earth's ICB is irregular, with a combination of at least two scales of topography: a height variation of 14 km changing within a lateral distance of no more than 6 km, and a height variation of 4-8 km with a lateral length scale of 2-4 km. The characteristics of the ICB topography indicate that small-scale variations of temperature and/or core composition exist near the ICB, and/or the ICB topographic surface is being deformed by small-scale forces out of its thermocompositional equilibrium position and is metastable.

What We Do Not Yet Know About Global Ocean Depths, and How Satellite Altimetry Can Help

NASA Astrophysics Data System (ADS)

Smith, W. H. F.; Sandwell, D. T.; Marks, K. M.

2017-12-01

Half Earth's ocean floor area lies several km or more away from the nearest depth measurement. Areas more than 50 km from any sounding sum to a total area larger than the entire United States land area; areas more than 100 km from any sounding comprise a total area larger than Alaska. In remote basins the majority of available data were collected before the mid-1960s, and so often are mis-located by many km, as well as mis-digitized. Satellite altimetry has mapped the marine gravity field with better than 10 km horizontal resolution, revealing nearly all seamounts taller than 2 km; new data can detect some seamounts less than 1 km tall. Seafloor topography can be estimated from satellite altimetry if sediment is thin and relief is due to seafloor spreading and mid-plate volcanism. The accuracy of the estimate depends on the geological nature of the relief and on the accuracy of the soundings available to calibrate the estimation. At best, the estimate is a band-pass-filtered version of the true depth variations, but does not resolve the small-scale seafloor roughness needed to model mixing and dissipation in the ocean. In areas of thick or variable sediment cover there can be little correlation between depth and altimetry. Yet altimeter-estimated depth is the best guess available in most of the ocean. The MH370 search area provides an illustration. Prior to the search it was very sparsely (1% to 5%) covered by soundings, many of these were old, low-tech data, and plateaus with thick sediments complicate the estimation of depth from altimetry. Even so, the estimate was generally correct about the tectonic nature of the terrain and the extent of depth variations to be expected. If ships will fill gaps strategically, visiting areas where altimetry shows that interesting features will be found, and passing near the centroids of the larger gaps, the data will be exciting in their own right and will also improve future altimetry estimates.

Correlation between continent area and elevation

NASA Astrophysics Data System (ADS)

Zhang, Y.

2004-12-01

This presentation is motivated by the following questions: (1) What factors determine the mean elevation and thickness of an individual continent? (2) How to explain the positive correlation between the mean height and area of individual continent? (3) Given total continental crust volume, what determines the mean thickness (and hence total area) of all continents? For example, Mean thickness of all continents is about 41 km. Mean land elevation is 874 m, and mean elevation of all continents (including land areas and continental shelves and slopes to 1000 meters below sea level) is about 800 m. Could mean continental thickness have doubled and continental area have halved in the geologic past? I present a first-order model to address these issues assuming that continental mean height is the steady state height controlled by uplift and erosion. The model predicts that it takes longer time to erode a larger continent. Hence mean continental height at steady state increases as continental area increases. This prediction is consistent with the general trend between present-day continental elevation and area (except for Antarctica), and can fit the trend well. This is the first time the relation between continental area and mean elevation is quantitatively explained. The model is further applied to investigate variations of mean thickness of continental crust over the last 600 Myr over which the continental crust mass and seawater volume are assumed to be constant. Because a change in the number of continents leads to change in the area of continents, it is predicted that the mean continental thickness increases as the number of continents decreases. Nevertheless, the thickness variation is small, amounts to about 10% from one continent to six continents. Change in the number of continents leads to a sea level fluctuation of about 0.3 km, with the lowest sea level coinciding with times of supercontinents. This prediction is consistent with prominent lows in sea level curves at the times of Pangea and Rodinia. It is concluded that the number of continents played a major role in Phanerozoic sea level changes.

Multiple intermediates on the energy landscape of a 15-HEAT-repeat protein

PubMed Central

Tsytlonok, Maksym; Craig, Patricio O.; Sivertsson, Elin; Serquera, David; Perrett, Sarah; Best, Robert B.; Wolynes, Peter G.; Itzhaki, Laura S.

2014-01-01

Repeat proteins are a special class of modular, non-globular proteins composed of small structural motifs arrayed to form elongated architectures and stabilised solely by short-range contacts. We find a remarkable complexity in the unfolding of the large HEAT repeat protein PR65/A. In contrast to what has been seen for small repeat proteins in which unfolding propagates from one end, the HEAT array of PR65/A ruptures at multiple distant sites, leading to intermediate states with non-contiguous folded subdomains. Kinetic analysis allows us to define a network of intermediates and to delineate the pathways that connect them. There is a dominant sequence of unfolding, reflecting a non-uniform distribution of stability across the repeat array; however the unfolding of certain intermediates is competitive, leading to parallel pathways. Theoretical models accounting for the heterogeneous contact density in the folded structure are able to rationalize the variation in stability across the array. This variation in stability also suggests how folding may direct function in a large repeat protein: The stability distribution enables certain regions to present rigid motifs for molecular recognition while affording others flexibility to broaden the search area as in a fly-casting mechanism. Thus PR65/A uses the two ends of the repeat array to bind diverse partners and thereby coordinate the dephosphorylation of many different substrates and of multiple sites within hyperphosphorylated substrates. PMID:24120762

Precision and accuracy of age estimates obtained from anal fin spines, dorsal fin spines, and sagittal otoliths for known-age largemouth bass

USGS Publications Warehouse

Klein, Zachary B.; Bonvechio, Timothy F.; Bowen, Bryant R.; Quist, Michael C.

2017-01-01

Sagittal otoliths are the preferred aging structure for Micropterus spp. (black basses) in North America because of the accurate and precise results produced. Typically, fisheries managers are hesitant to use lethal aging techniques (e.g., otoliths) to age rare species, trophy-size fish, or when sampling in small impoundments where populations are small. Therefore, we sought to evaluate the precision and accuracy of 2 non-lethal aging structures (i.e., anal fin spines, dorsal fin spines) in comparison to that of sagittal otoliths from known-age Micropterus salmoides (Largemouth Bass; n = 87) collected from the Ocmulgee Public Fishing Area, GA. Sagittal otoliths exhibited the highest concordance with true ages of all structures evaluated (coefficient of variation = 1.2; percent agreement = 91.9). Similarly, the low coefficient of variation (0.0) and high between-reader agreement (100%) indicate that age estimates obtained from sagittal otoliths were the most precise. Relatively high agreement between readers for anal fin spines (84%) and dorsal fin spines (81%) suggested the structures were relatively precise. However, age estimates from anal fin spines and dorsal fin spines exhibited low concordance with true ages. Although use of sagittal otoliths is a lethal technique, this method will likely remain the standard for aging Largemouth Bass and other similar black bass species.

Genotype and local environment dynamically influence growth, disturbance response and survivorship in the threatened coral, Acropora cervicornis.

PubMed

Drury, Crawford; Manzello, Derek; Lirman, Diego

2017-01-01

The relationship between the coral genotype and the environment is an important area of research in degraded coral reef ecosystems. We used a reciprocal outplanting experiment with 930 corals representing ten genotypes on each of eight reefs to investigate the influence of genotype and the environment on growth and survivorship in the threatened Caribbean staghorn coral, Acropora cervicornis. Coral genotype and site were strong drivers of coral growth and individual genotypes exhibited flexible, non-conserved reaction norms, complemented by ten-fold differences in growth between specific G-E combinations. Growth plasticity may diminish the influence of local adaptation, where foreign corals grew faster than native corals at their home sites. Novel combinations of environment and genotype also significantly affected disturbance response during and after the 2015 bleaching event, where these factors acted synergistically to drive variation in bleaching and recovery. Importantly, small differences in temperature stress elicit variable patterns of survivorship based on genotype and illustrate the importance of novel combinations of coral genetics and small differences between sites representing habitat refugia. In this context, acclimatization and flexibility is especially important given the long lifespan of corals coping with complex environmental change. The combined influence of site and genotype creates short-term differences in growth and survivorship, contributing to the standing genetic variation needed for adaptation to occur over longer timescales and the recovery of degraded reefs through natural mechanisms.

Relationships between stem diameter, sapwood area, leaf area and transpiration in a young mountain ash forest.

PubMed

Vertessy, R A; Benyon, R G; O'Sullivan, S K; Gribben, P R

1995-09-01

We examined relationships between stem diameter, sapwood area, leaf area and transpiration in a 15-year-old mountain ash (Eucalyptus regnans F. Muell.) forest containing silver wattle (Acacia dealbata Link.) as a suppressed overstory species and mountain hickory (Acacia frigescens J.H. Willis) as an understory species. Stem diameter explained 93% of the variation in leaf area, 96% of the variation in sapwood area and 88% of the variation in mean daily spring transpiration in 19 mountain ash trees. In seven silver wattle trees, stem diameter explained 87% of the variation in sapwood area but was a poor predictor of the other variables. When transpiration measurements from individual trees were scaled up to a plot basis, using stem diameter values for 164 mountain ash trees and 124 silver wattle trees, mean daily spring transpiration rates of the two species were 2.3 and 0.6 mm day(-1), respectively. The leaf area index of the plot was estimated directly by destructive sampling, and indirectly with an LAI-2000 plant canopy analyzer and by hemispherical canopy photography. All three methods gave similar results.

33 CFR 334.155 - Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. 334.155 Section 334.155 Navigation and... RESTRICTED AREA REGULATIONS § 334.155 Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. (a) The area. The waters within the Naval Station Annapolis small boat basin and...

33 CFR 334.155 - Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. 334.155 Section 334.155 Navigation and... RESTRICTED AREA REGULATIONS § 334.155 Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. (a) The area. The waters within the Naval Station Annapolis small boat basin and...

33 CFR 334.155 - Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. 334.155 Section 334.155 Navigation and... RESTRICTED AREA REGULATIONS § 334.155 Severn River, Naval Station Annapolis, Small Boat Basin, Annapolis, MD; naval restricted area. (a) The area. The waters within the Naval Station Annapolis small boat basin and...

Distribution of elements in the Salt Wash member of the Morrison Formation in the Jo Dandy area, Montrose County, Colorado

USGS Publications Warehouse

Newman, William L.; Elston, Donald P.

1957-01-01

A study of the distribution of elements in the Salt Wash member of the Morrison formation of Jurassic age from samples taken in the Jo Dandy area, Montrose County, Colo., was made to determine average chemical composition of mudstone and sandstone and to determine the magnitude of variations in concentrations of elements within similar rock types. Analytical data were obtained by semiquantitative spectrographic and radiometric methods. Results of the study show that variations in concentrations of about 20 elements commonly detected by semiquantititive spectrographic analyses of sedimentary rocks are small for a specific rock type; therefore, considerable confidence may be placed upon the average chemical appears to be no significant relation between chemical composition of mudstone or sandstone and distance from known uranium-vanadium ore or mineralization rock. Mudstone generally contains greater concentrations of the elements studied than sandstone. The chemical composition of red mudstone is similar to the chemical composition of green mudstone except that red mudstone was found to contain almost twice as much calcium as green mudstone in the Jo Dandy area. Samples of the unoxidized sandstone from the Jo Dandy area contain about twice as much calcium, three times as much strontium, but only about one-half as much as zirconium as oxidized sandstone; except for these elements the chemical compositions of both categories of sandstone are similar. Samples of sandstone of the Salt Wash member in the Jo Dandy area contain more potassium, magnesium, vanadium, and nickel than “average sandstone” of the Salt Wash member. The distribution of bismuth in rocks of the Jo Dandy area suggests that bismuth and perhaps part of the potassium and magnesium found in rocks of the Salk Wash member were either derived from solutions which ascended from the underlying salt- and gypsum-bearing Paradox member that was incorporated with rocks of the Salt Wash during sedimentation.

Why prostate tumour delineation based on apparent diffusion coefficient is challenging: an exploration of the tissue microanatomy.

PubMed

Borren, Alie; Moman, Maaike R; Groenendaal, Greetje; Boeken Kruger, Arto E; van Diest, Paul J; van der Groep, Petra; van der Heide, Uulke A; van Vulpen, Marco; Philippens, Marielle E P

2013-11-01

Focal boosting of prostate tumours to improve outcome, requires accurate tumour delineation. For this, the apparent diffusion coefficient (ADC) derived from diffusion-weighted MR imaging (DWI) seems a useful tool. On voxel level, the relationship between ADC and histological presence of tumour is, however, ambiguous. Therefore, in this study the relationship between ADC and histological variables was investigated on voxel level to understand the strengths and limitations of DWI for prostate tumour delineation. Twelve radical prostatectomy patients underwent a pre-operative 3.0T DWI exam and the ADC was calculated. From whole-mount histological sections cell density and glandular area were retrieved for every voxel. The distribution of all variables was described for tumour, peripheral zone (PZ) and central gland (CG) on regional and voxel level. Correlations between variables and differences between regions were calculated. Large heterogeneity of ADC on voxel level was observed within tumours, between tumours and between patients. This heterogeneity was reflected by the distribution of cell density and glandular area. On regional level, tumour was different from PZ having higher cell density (p = 0.007), less glandular area (p = 0.017) and lower ADCs (p = 0.017). ADC was correlated with glandular area (r = 0.402) and tumour volume (r = -0.608), but not with Gleason score. ADC tended to decrease with increasing cell density (r = -0.327, p = 0.073). On voxel level, correlations between ADC and histological variables varied among patients, for cell density ranging from r = -0.439 to r = 0.261 and for glandular area from r = 0.593 to r = 0.207. The variation in ADC can to a certain extent be explained by the variation in cell density and glandular area. The ADC is highly heterogeneous, which reflects the heterogeneity of malignant and benign prostate tissue. This heterogeneity might however obscure small tumours or parts of tumours. Therefore, DWI has to be used in the context of multiparametric MRI.

49 CFR 325.9 - Measurement tolerances.

Code of Federal Regulations, 2011 CFR

2011-10-01

... reporting filed sound level measurements to the nearest whole decibel. (2) Variations resulting from... atmospheric pressure. (5) Variations resulting from reflected sound from small objects allowed within the test...