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Sample records for northern conditions influencing

  1. Nutritional condition of Northern Yellowstone Elk

    USGS Publications Warehouse

    Cook, R.C.; Cook, J.G.; Mech, L.D.

    2004-01-01

    Ultrasonography and body condition scoring was used to estimate nutritional condition of northern Yellowstone elk in late winter. Probability of pregnancy was related to body fat, and lactating cows had 50% less fat than non-lactating cows. For mild to normal winters, most of the elk were in good condition.

  2. Influence of Sub-Surface Irrigation on Soil Conditions and Water Irrigation Efficiency in a Cherry Orchard in a Hilly Semi-Arid Area of Northern China

    PubMed Central

    Peng, Gao; Bing, Wang; Guangcan, Zhang

    2013-01-01

    Sub-surface irrigation (SUI) is a new water-saving irrigation technology. To explore the influence of SUI on soil conditions in a cherry orchard and its water-saving efficiency, experiments were conducted from 2009 to 2010 using both SUI and flood irrigation (FLI) and different SUI quotas in hilly semi-arid area of northern China. The results demonstrated the following: 1) The bulk density of the soil under SUI was 6.8% lower than that of soil under FLI (P<0.01). The total soil porosity, capillary porosity and non-capillary porosity of soils using SUI were 11.7% (P<0.01), 8.7% (P<0.01) and 43.8% (P<0.01) higher than for soils using FLI. 2) The average soil temperatures at 0, 5, 10, 15 and 20 cm of soil depth using SUI were 1.7, 1.1, 0.7, 0.4 and 0.3°C higher than those for FLI, specifically, the differences between the surface soil layers were more significant. 3) Compared with FLI, the average water-saving efficiency of SUI was 55.6%, and SUI increased the irrigation productivity by 7.9-12.3 kg m-3 ha-1. 4) The soil moisture of different soil layers using SUI increased with increases in the irrigation quotas, and the soil moisture contents under SUI were significantly higher in the 0-20 cm layer and in the 21-50 cm layer than those under FLI (P<0.01). 5) The average yields of cherries under SUI with irrigation quotas of 80-320 m3 ha-1 were 8.7%-34.9% higher than those in soil with no irrigation (CK2). The average yields of cherries from soils using SUI were 4.5%-12.2% higher than using FLI. It is appropriate to irrigate 2-3 times with 230 m3 ha-1 per application using SUI in a year with normal rainfall. Our findings indicated that SUI could maintain the physical properties, greatly improve irrigation water use efficiency, and significantly increase fruit yields in hilly semi-arid areas of northern China. PMID:24039986

  3. Season - dependent and source-influenced aerosol in Northern Siberia

    NASA Astrophysics Data System (ADS)

    Popovicheva, Olga; Makshtas, Alexander; Bogorodsky, Peter; Eleftheriadis, Kostantinos; Diapouli, Evangelia; Shonia, Natalia; Uttal, Taneil

    2016-04-01

    Aerosol may serve as a tracer of arctic pollution, allowing a link to climate response if its major characteristics relating to natural and anthropogeneous sources are defined. It has been shown that BC and sulfates are the most important aerosol constituents measured in the Arctic boundary layer; these species demonstrate similar seasonal variations with a peak during winter to early spring and a minimum in summer. Long - time gap in consistent aerosol observations in the Russian Arctic strongly limits the assessment of air pollution and climate impacts. On-line monitoring, sampling, and analyses of atmospheric aerosols were carried out at the Tiksi Hydrometeorological Observatory, Northern Siberia, during one year from September 2014 to 2015. Physico-chemical characterization combining aethalometry, thermo-optical analysis, and analytical chemistry was used in order to identify the seasonal variability of aerosols and to link their composition to possible sources, as well as to characterize the differences in aerosol chemical composition between natural background conditions and BC-pollution episodes. The present study reports the first results from the Tiksi Observatory on season-dependent and source-influenced characteristics of aerosol species, such as carbon fractions (OC, EC), inorganic and organic functionalities of chemical compounds, sulfates, nitrates and other ion components, and elements. In addition, data obtained by individual particles analysis provide insight into micromarkers of combustion sources. Aerosol at the Tiksi Observatory is found to be originated from natural marine, biogenic, and continental sources as well as influenced by local residential activity and regional pollution. Characterization of aerosols during OC and BC-pollution episodes, combined with analysis of the wind direction, atmosphere stability, and air mass trajectories, allows for the identification of the sources which are responsible for the emission of hazardous compounds

  4. Factors influencing reproductive performance of northern bobwhite in South Florida

    USGS Publications Warehouse

    Rolland, V.; Hostetler, J.A.; Hines, T.C.; Percival, H.F.; Oli, M.K.

    2011-01-01

    Reproductive success is a critical component of individual fitness, and also an important determinant of growth rates of populations characterized by early maturity and high fecundity. We used radiotelemetry data collected during 2003-2008 to estimate reproductive parameters in a declining northern bobwhite (Colinus virginianus) population in South Florida, and to test hypotheses regarding factors influencing these parameters. The overall clutch size was 12.10 ?? 0.22, but females laid more eggs in their first clutch (12.43 ?? 0.24) than in subsequent clutches (10.19 ?? 0.53) within a nesting season. Daily nest survival was higher for first (0.966 ?? 0.003) than subsequent nests (0.936 ?? 0.011). Hatchability (proportion of laid eggs that hatched conditional upon nest survival to hatching) was 0.853 ?? 0.008, but was higher for nests incubated by females (0.873 ?? 0.009) than those incubated by males (0.798 ?? 0.018). The proportion of individuals attempting a second nest was 0.112 ?? 0.024 and 0.281 ?? 0.040 when the first nest was successful and failed, respectively. Hatchability was lower when the nesting habitat was burned the previous winter. We found no evidence that food strip density (a management practice to provide supplemental food) influenced any of the reproductive parameters. Mean summer temperature affected hatchability, nest survival, and proportion of nests incubated by males. Overall, the reproductive output in our study population was lower than that reported for most other bobwhite populations, indicating that low reproductive performance may have contributed to bobwhite population declines in our study site. These results suggest that current management practices, particularly those related to habitat and harvest management, need careful evaluation. ?? 2010 Springer-Verlag.

  5. Atmospheric and oceanologic conditions favouring large bioproduction of northern Adriatic

    NASA Astrophysics Data System (ADS)

    Kraus, Romina; Lučić, Davor; Njire, Jakica; Djakovac, Tamara; Precali, Robert; Supić, Nastjenjka

    2016-04-01

    An interdisciplinary study based on long term data collected in the northern Adriatic relieved winter period to be crucial for the total annual zooplankton production in the region. Namely, yearly averages of some investigated zooplankton species in the 2000-2007 interval were highly related to their February and/or March abundances. The large winter zooplankton abundances appeared in winters of the "A type", in which freshened waters from the Po River spread over the region. Also, the production of phytoplankton was in winters of the "A type" higher than in winters of the "B type", in which these waters are restricted to the coastal areas and do not impact the open sea. That was presumably due to increase in nutrients. In fact, the total inorganic nitrogen and ortophosphate concentration in eastern part reached maximal February values in the 1990-2007 interval in winters of the "A type". Spreading of the Po River water across the northern Adriatic and appearance of the two winter types depends on the existing geostrophic circulation patterns and atmospheric and hydrologic conditions in the preceding months, thus enabling forecast. Obtained results are basis for the future theoretical ecological model which can explain long term changes in bioproduction in the region and be used in planning future environment actions aimed to sustained development, especially as winter phytoplankton and zooplankton production seems to reflect on annual catch of small pelagic fish important for Adriatic fishery, anchovy (Engraulis encrasicolus).

  6. Stratospheric influence on Northern Hemisphere winter climate variability

    NASA Astrophysics Data System (ADS)

    Ouzeau, Gaelle; Douville, Herve; Saint Martin, David

    2010-05-01

    Despite significant improvements in observing and data assimilation systems, long-range dynamical forecasting remains a difficult challenge for the climate modelling community. The skill of operational seasonal forecasting systems is particularly poor in the northern extratropics where seas surface temperature (SST) has a weaker influence than in the Tropics. It is therefore relevant to look for additional potential sources of long-range climate predictability in the stratosphere using ensembles of global atmospheric simulations. Besides a control experiment where the ARPEGE-Climat model is only driven by SST, parallel simulations have been performed in which an additional control on climate variability has been accounted for through the nudging of the northern extratropical stratosphere towards the ERA40 reanalysis. Though idealized, this original experiment design allows us to compare the relative contribution of the lower and upper boundary forcings on the simulated tropospheric variability. Results show that the stratospheric nudging improves the climatology and interannual variability of the mid-latitude troposphere, especially in winter in the Northern Hemisphere. Major impacts are found in particular on the simulation of the Arctic and North Atlantic oscillations (AO and NAO). Case studies were carried out for the 1976-1977 and 1988-1989 winters, corresponding to extreme phases of the AO. Results confirm the robustness of the positive impact of the nudging, especially for winter 1976-1977 corresponding to relatively weak SST anomalies in the tropical Pacific. A sensitivity study to the model resolution shows that a well-resolved stratosphere is not necessary for the nudging to be efficient. Besides seasonal mean results, analysis of the day-to-day variability in winter allowed us to better understand the stratospheric polar vortex influence on the tropospheric circulation in the Northern Hemisphere mid-latitudes.

  7. Influences Preceding "Nunatsiavut" Self-Determination: Historical, Political and Educational Influences on the People of Northern Labrador (Canada)

    ERIC Educational Resources Information Center

    Anderson, Kirk David

    2007-01-01

    What were the influences on the Inuit of Northern Labrador preceding the creation of the self-governing territory of Nunatsiavut? What are the preterritorial influences of the Inuit on the territory's five schools? To answer these questions and to share the success of one Indigenous people, the Nunatsiavut Inuit (the Inuit of Northern Labrador,…

  8. Impact of mesoscale meteorological processes on anomalous radar propagation conditions over the northern Adriatic area

    NASA Astrophysics Data System (ADS)

    Telišman Prtenjak, Maja; Horvat, Igor; Tomažić, Igor; Kvakić, Marko; Viher, Mladen; Grisogono, Branko

    2015-09-01

    The impact of mesoscale structures on the occurrence of anomalous propagation (AP) conditions for radio waves, including ducts, superrefractive, and subrefractive conditions, was studied. The chosen meteorological situations are the bora wind and the sporadic sea/land breeze (SB/LB) during three selected cases over a large portion of the northern Adriatic. For this purpose, we used available radio soundings and numerical mesoscale model simulations (of real cases and their sensitivity tests) at a horizontal resolution of 1.5 km and 81 vertical levels. The model simulated the occurrences of AP conditions satisfactorily, although their intensities and frequency were underestimated at times. Certain difficulties appeared in reproducing the vertical profile of the modified refractive index, which is mainly dependent on the accuracy of the modeled humidity. The spatial distributions of summer AP conditions reveal that the surface layer above the sea (roughly between 30 and 100 m asl) is often covered by superrefractive conditions and ducts. The SB is highly associated with the formations of AP conditions: (i) in the first 100 m asl, where trapping and superrefractive conditions form because of the advection of cold and moist air, and (ii) inside the transition layer between the SB body and the elevated return flow in the form of subrefractive conditions. When deep convection occurs, all three types of AP conditions are caused by the downdraft beneath the cumulonimbus cloud base in its mature phase that creates smaller but marked pools of cold and dry air. The bora wind usually creates a pattern of AP conditions associated with the hydraulic jump and influences distribution of AP conditions over the sea surface.

  9. Icing Conditions Over Northern Eurasia in Changing Climate

    NASA Astrophysics Data System (ADS)

    Bulygina, O.; Arzhanova, N.; Groisman, P. Y.

    2013-12-01

    Climate of the Russian Federation for the national territory. This Reference Book addresses the current state of these weather phenomena. However, the ongoing and projected humidity changes in the high latitudes will strongly affect the circum-polar area (land and ocean) and impact the frequency and intensity of these potentially dangerous weather phenomena across the entire extratropical land area. Therefore the goal of the present study is to quantify icing conditions over the northern Eurasia. Our analysis includes data of 958 Russian stations from 1977 to 2012. Regional analysis of gololed characteristics was carried out using quasi-homogeneous climatic regions. Maps (climatology, trends) are presented mostly for visualization purposes. The area-averaging technique using station values converted to anomalies with respect to a common reference period (in this study, from 1977 to 2012). Anomalies were arithmetically averaged first within 1N x 2E grid cells and thereafter by a weighted average value derived over the quasi-homogeneous climatic regions. This approach provides a more uniform spatial field for averaging.

  10. Environmental Conditions in northern Gulf of Mexico Estuaries: before and after the BP Oil Spill

    EPA Science Inventory

    This presentation provides a summary of ecological condition and sediment chemistry data for northern Gulf of Mexico estuaries that were exposed to oil and oil-related contaminants from the BP Oil Spill.

  11. Harmful and favourable ultraviolet conditions for human health over Northern Eurasia

    NASA Astrophysics Data System (ADS)

    Chubarova, Nataly; Zhdanova, Ekaterina

    2014-05-01

    We provide the analysis of the spatial and temporal distribution of ultraviolet (UV) radiation over Northern Eurasia taking into account for both its detrimental (erythema and eye-damage effects) and favourable (vitamin D synthesis) influence on human health. The UV effects on six different skin types are considered in order to cover the variety of skin types of European and Asian inhabitants. To better quantifying the vitamin D irradiance threshold we accounted for an open body fraction S as a function of effective air temperature. The spatial and temporal distribution of UV resources was estimated by radiative transfer (RT) modeling (8 stream DISORT RT code) with 1x 1 degree grid and monthly resolution. For this purpose special datasets of main input geophysical parameters (total ozone content, aerosol characteristics, surface UV albedo, UV cloud modification factor) have been created over the territory of Northern Eurasia, which can be of separate interest for the different multidisciplinary scientific applications over the PEEX domain. The new approaches were used to retrieve aerosol and cloud transmittance from different satellite and re-analysis datasets for calculating the solar UV irradiance at ground. Using model simulations and some experimental data we provide the altitude parameterization for different types of biologically active irradiance in mountainous area taking into account not only for the effects of molecular scattering but for the altitude dependence of aerosol parameters and surface albedo. Based on the new classification of UV resources (Chubarova, Zhdanova, 2013) we show that the distribution of harmful (UV deficiency and UV excess) and favorable UV conditions is regulated by various geophysical parameters (mainly, total ozone, cloudiness and open body fraction) and can significantly deviate from latitudinal dependence. The interactive tool for providing simulations of biologically active irradiance and its attribution to the different

  12. Game Theory, Conditional Preferences, and Social Influence

    PubMed Central

    Stirling, Wynn C.; Felin, Teppo

    2013-01-01

    Neoclassical noncooperative game theory is based on a simple, yet powerful synthesis of mathematical and logical concepts: unconditional and immutable preference orderings and individual rationality. Although this structure has proven useful for characterizing competitive multi-player behavior, its applicability to scenarios involving complex social relationships is problematic. In this paper we directly address this limitation by the introduction of a conditional preference structure that permits players to modulate their preference orderings as functions of the preferences of other players. Embedding this expanded preference structure in a formal and graphical framework provides a systematic approach for characterizing a complex society. The result is an influence network that allows conditional preferences to propagate through the community, resulting in an emergent social model which characterizes all of the social relationships that exist and which leads to solution concepts that account for both group and individual interests. The Ultimatum game is presented as an example of how social influence can be modeled with conditional preferences. PMID:23451078

  13. The northern Yellowstone elk: density dependence and climatic conditions

    USGS Publications Warehouse

    Taper, Mark L.; Gogan, Peter J.P.

    2002-01-01

    We analyzed a time series of estimates of elk (Cervus elaphus) numbers on the northern Yellowstone winter range from 1964 to 1979 and 1986 to 1995 using a variety of discrete time stochastic population dynamic models. These models included adjustments for density, an increase in the area of winter range used by elk, lagged effects of the weather covariates of spring precipitation, snow depth and winter temperature, and the impacts of the 1988 drought and fires. An information-criteria-based model-selection process strongly supported evidence of density dependence. The best model, a Ricker model, distinguished between the 2 time periods. The bulk of the difference between the 2 periods is attributed to an increase in the amount of winter range used by elk. Inclusion of the covariates spring precipitation and spring precipitation squared greatly improved the model fit. We detected a short-lived increase in elk population growth rate following the 1988 drought and fires. Fertility and survivorship of adults appeared to have different density-dependent forms that together result in a biphasic relationships between population growth rate and density. This study confirms the presence of density-dependent regulation in the norther Yellowstone elk herd, and enhances our understanding of population dynamics of these ungulates.

  14. Climatic conditions in northern Canada: past and future.

    PubMed

    Prowse, Terry D; Furgal, Chris; Bonsal, Barrie R; Edwards, Thomas W D

    2009-07-01

    This article reviews the historical, instrumental, and future changes in climate for the northern latitudes of Canada. Discussion of historical climate over the last 10 000 years focuses on major climatic shifts including the Medieval Warm Period and the Little Ice Age, and how these changes compare with those most recently experienced during the period of instrumental records. In reference to the latter, details are noted about observed trends in temperature and precipitation that have been recorded over the last half century, which exhibit strong west to east and north to south spatial contrasts. A comprehensive review of future changes is also provided based on outputs from seven atmosphere-ocean global climate models and six emission scenarios. Discussion focuses on annual, seasonal, and related spatial changes for three 30-year periods centered on the 2020s, 2050s, and 2080s. In summary, substantial changes to temperature and precipitation are projected for the Canadian North during the twenty-first century. Although there is considerable variability within the various projections, all scenarios show higher temperature and, for the most part, increasing precipitation over the entire region. PMID:19714958

  15. The combined influences of autumnal snow and sea ice on Northern Hemisphere winters

    NASA Astrophysics Data System (ADS)

    Furtado, J. C.; Cohen, J. L.; Tziperman, E.

    2016-04-01

    Past studies have demonstrated a significant relationship between the phase and amplitude of the Northern Annular Mode (NAM) and both Arctic sea ice and high-latitude snow cover during boreal autumn. However, those studies have considered these forcings separately. Here we consider the collective effect of Arctic sea ice and snow cover variability for producing skillful subseasonal forecasts for Northern Hemisphere (NH) winter conditions. We find that these two cryospheric elements interact with the extratropical atmosphere differently through the cold season. Sea ice extent minima during November play a role in stratospheric and tropospheric circulation anomalies during November/December with a secondary maximum in late January/February. October snow cover anomalies, however, have impacts on the NAM primarily during middle to late winter. These timing differences are likely tied to differences in anomalous wave driving between the two cases, though other processes may be in play. We exploit these different influences to produce a skillful forecast model of subseasonal NH surface temperatures using both sea ice and snow cover as predictors, with large gains in skills in January. Overall, our study suggests that the Arctic has a demonstrable and detectable influence on midlatitude winter weather in the present and likely future climate.

  16. Body condition of Morelet’s Crocodiles (Crocodylus moreletii) from northern Belize

    USGS Publications Warehouse

    Mazzotti, Frank J.; Cherkiss, Michael S.; Brandt, Laura A.; Fujisaki, Ikuko; Hart, Kristen; Jeffery, Brian; McMurry, Scott T.; Platt, Steven G.; Rainwater, Thomas R.; Vinci, Joy

    2012-01-01

    Body condition factors have been used as an indicator of health and well-being of crocodilians. We evaluated body condition of Morelet's Crocodiles (Crocodylus moreletii) in northern Belize in relation to biotic (size, sex, and habitat) and abiotic (location, water level, and air temperature) factors. We also tested the hypothesis that high water levels and warm temperatures combine or interact to result in a decrease in body condition. Size class, temperature, and water level explained 20% of the variability in condition of Morelet's Crocodiles in this study. We found that adult crocodiles had higher condition scores than juveniles/subadults but that sex, habitat, and site had no effect. We confirmed our hypothesis that warm temperatures and high water levels interact to decrease body condition. We related body condition of Morelet's Crocodiles to natural fluctuations in air temperatures and water levels in northern Belize, providing baseline conditions for population and ecosystem monitoring.

  17. Dissolved oxygen conditions in northern Gulf of Mexico estuaries

    USGS Publications Warehouse

    Engle, V.D.; Kevin, Summers J.; Macauley, J.M.

    1999-01-01

    Because deficient dissolved oxygen (DO) levels may have severe detrimental effects on estuarine and marine life, DO has been widely used as an indicator of ecological conditions by environmental monitoring programs. The U.S. EPA's Environmental Monitoring and Assessment Program for Estuaries (EMAP-E) monitored DO conditions in the estuaries of the Gulf of Mexico from 1991 to 1994. DO was measured in two ways: 1)instantaneous profiles from the surface to the bottom were taken during the day, and 2) continuous measurements were taken near the bottom at 15 min intervals for at least 12 h. This information was summarized to assess the spatial distribution and severity of DO conditions in these estuaries. Depending on the criteria used to define hypoxia (DO concentrations usually < 2 mg L-1 or 15 mg L-1) and the method by which DO is measured, we estimate that between 5.2 and 29.3% of the total estuarine area in the Louisianian Province was affected by low DO conditions.

  18. Mental distress and social conditions and lifestyle in northern Norway.

    PubMed Central

    Hansen, V.; Jacobsen, B. K.

    1989-01-01

    In a cross sectional survey of risk factors for coronary heart disease three questions about mental distress were included in a questionnaire completed by 13,704 people, 64% of the total population aged 20-54 in one municipality. Overall, 860 (12.5%) of the men and 1141 (16.8%) of the women reported having at least one symptom of mental distress. There were no distinct differences between the age groups. Single people, separated and divorced people, and those who reported that the financial situation of the family during their childhood was difficult reported more mental problems. Heavy smoking, frequent alcohol consumption, and, in men, little or no physical activity in leisure time were also associated with a high prevalence of mental distress. By multiple regression analyses, marital state, financial situation of family during childhood, and current lifestyle were found to be highly significantly associated with mental distress. Including a few questions on mental distress in health surveys provides a way to establish relations between such symptoms and social conditions and lifestyle in large numbers of subjects. PMID:2504341

  19. Icing conditions over Northern Eurasia in changing climate

    NASA Astrophysics Data System (ADS)

    Bulygina, Olga N.; Arzhanova, Natalia M.; Groisman, Pavel Ya

    2015-02-01

    Icing conditions, particularly in combination with wind, affect greatly the operation of overhead communication and transmission lines causing serious failures, which result in tremendous economic damage. Icing formation is dangerous to agriculture, forestry, high seas fishery, for land and off coast man-made infrastructure. Quantitative icing characteristics such as weight, thickness, and duration are very important for the economy and human wellbeing when their maximum values exceed certain thresholds. Russian meteorological stations perform both visual and instrumental monitoring of icing deposits. Visual monitoring is ocular estimation of the type and intensity of icing and the date of ice appearance and disappearance. Instrumental monitoring is performed by ice accretion indicator that in addition to the type, intensity and duration of ice deposits reports also their weight and size. We used observations at 958 Russian stations for the period 1977-2013 to analyze changes in the ice formation frequency at individual meteorological stations and on the territory of quasi-homogeneous climatic regions in Russia. It was found that hoar frosts are observed in most parts of Russia, but icing only occurs in European Russia and the Far East. On the Arctic coast of Russia, this phenomenon can even be observed in summer months. Statistically significant decreasing trends in occurrence of icing and hoar frost events are found over most of Russia. An increasing trend in icing weights (IWs) was found in the Atlantic Arctic region in autumn. Statistically significant large negative trends in IWs were found in the Pacific Arctic in winter and spring.

  20. Condition and mass impact oxygen stores and dive duration in adult female northern elephant seals.

    PubMed

    Hassrick, J L; Crocker, D E; Teutschel, N M; McDonald, B I; Robinson, P W; Simmons, S E; Costa, D P

    2010-02-15

    The range of foraging behaviors available to deep-diving, air-breathing marine vertebrates is constrained by their physiological capacity to breath-hold dive. We measured body oxygen stores (blood volume and muscle myoglobin) and diving behavior in adult female northern elephant seals, Mirounga angustirostris, to investigate age-related effects on diving performance. Blood volume averaged 74.4+/-17.0 liters in female elephant seals or 20.2+/-2.0% of body mass. Plasma volume averaged 32.2+/-7.8 liters or 8.7+/-0.7% of body mass. Absolute plasma volume and blood volume increased independently with mass and age. Hematocrit decreased weakly with mass but did not vary with age. Muscle myoglobin concentration, while higher than previously reported (7.4+/-0.7 g%), did not vary with mass or age. Pregnancy status did not influence blood volume. Mean dive duration, a proxy for physiological demand, increased as a function of how long seals had been at sea, followed by mass and hematocrit. Strong effects of female body mass (range, 218-600 kg) on dive duration, which were independent of oxygen stores, suggest that larger females had lower diving metabolic rates. A tendency for dives to exceed calculated aerobic limits occurred more frequently later in the at-sea migration. Our data suggest that individual physiological state variables and condition interact to determine breath-hold ability and that both should be considered in life-history studies of foraging behavior. PMID:20118309

  1. Climatic and topographical influences on fire regime attributes in the northern Cascade Range, Washington, USA

    NASA Astrophysics Data System (ADS)

    Cansler, C.; McKenzie, D.

    2010-12-01

    We examined the influence of annual climate and topography on fire occurrence, size, severity, and within-fire severity pattern in the northern Cascade Range of Washington, USA. Landsat Thematic Mapper (LTM) data were used to quantify fire severity for all fires greater than 10 ha (n = 125) that occurred during a 25 year period (1984-2008). Categorical burn severity images were developed from an index of burn severity (Relative differenced Normalized Burn Ratio) derived from LTM data and parameterized with data from 639 field plots. Spring snowpack and summer temperature were negatively and positively correlated, respectively, with fire occurrence, annual area burned, and proportion of landscape burned at high severity. As the proportion of high severity within individual fires increased high severity patches became larger and increasingly spatially aggregated. Fires in areas with greater topographical complexity had lower proportional area burned at high severity, decreased spatial aggregation of individual burn severity classes, and more complex overall patch structure. These results show that the fire regime of the northern Cascade Range responds to annual climatic variation. Nevertheless, within-fire severity mosaic reflects the underlying topographic complexity, even under climatic conditions conducive to the development of large fires. Several recent studies in the western United States have documented a positive relationship between warm and dry climate conditions and annual area burned. The relationship between climate drivers and fire regime attributes identified in this study—a positive relationship between warm and dry conditions and both proportion of area burned at high severity and greater spatial aggregation of high severity patches—add nuance the climate-area burned relationship documented in previous studies.

  2. REMOTE ISCHEMIC CONDITIONING INFLUENCES MITOCHONDRIAL DYNAMICS

    PubMed Central

    Cellier, Laura; Tamareille, Sophie; Kalakech, Hussein; Guillou, Sophie; Lenaers, Guy; Prunier, Fabrice; Mirebeau-Prunier, Delphine

    2016-01-01

    ABSTRACT Remote ischemic preconditioning (RIPC) has emerged as an attractive strategy to protect the heart against ischemia-reperfusion (I/R) injury. The mechanisms by which remote ischemic conditioning (RIC) is protective are to date unknown, yet a well-accepted theory holds that the mitochondria play a central role. Mitochondria are dynamic organelles that undergo fusion and fission. Interventions that decrease mitochondrial fission or increase mitochondrial fusion have been associated with reduced I/R injury. However, whether RIPC influences mitochondrial dynamics or not has yet to be ascertained. We sought to determine the role played by mitochondrial dynamics in RIPC-induced cardioprotection. Male adult rats exposed in vivo to myocardial I/R were assigned to one of two groups, either undergoing 40 min of myocardial ischemia followed by 120 min of reperfusion (MI group) or four 5-min cycles of limb ischemia interspersed by 5 min of limb reperfusion, immediately prior to myocardial ischemia and 120 min of reperfusion (MI+RIPC group). After reperfusion, infarct size was assessed and myocardial tissue was analyzed by Western blot and electron microscopy. RIPC induced smaller infarct size (−28%), increased mitochondrial fusion protein OPA1, and preserved mitochondrial morphology. These findings suggest that mitochondrial dynamics play a role in the mechanisms of RIPC-induced cardioprotection. PMID:26555744

  3. Characterization of aerosols above the Northern Adriatic Sea: Case studies of offshore and onshore wind conditions

    NASA Astrophysics Data System (ADS)

    Piazzola, J.; Mihalopoulos, N.; Canepa, E.; Tedeschi, G.; Prati, P.; Zarmpas, P.; Bastianini, M.; Missamou, T.; Cavaleri, L.

    2016-05-01

    Aerosol particles in coastal areas result from a complex mixing between sea spray aerosols locally generated at the sea surface by the wind-waves interaction processes and a continental component resulting from natural and/or anthropogenic sources. This paper presents a physical and chemical analysis of the aerosol data acquired from May to September 2014 in the Adriatic Sea. Aerosol distributions were measured on the Acqua Alta platform located 15 km off the coast of Venice using two Particle Measuring System probes and a chemical characterization was made using an Ion Chromatography analysis (IC). Our aim is to study both the sea-spray contribution and the anthropogenic influence in the coastal aerosol of this Mediterranean region. To this end, we focus on a comparison between the present data and the aerosol size distributions measured south of the French Mediterranean coast. For air masses of marine origin transported by southern winds on the French coast and by the Sirocco in the Adriatic, we note a good agreement between the concentrations of super-micrometer aerosols measured in the two locations. This indicates a similar sea surface production of sea-spray aerosols formed by bubble bursting processes in the two locations. In contrast, the results show larger concentrations of submicron particles in the North-Western Mediterranean compared to the Adriatic, which result probably from a larger anthropogenic background for marine conditions. In contrast, for a coastal influence, the chemical analysis presented in the present paper seems to indicate a larger importance of the anthropogenic impact in the Northern Adriatic compared to the North-Western Mediterranean.

  4. Characterization of aerosols above the Northern Adriatic Sea: Case studies of offshore and onshore wind conditions

    NASA Astrophysics Data System (ADS)

    Piazzola, J.; Mihalopoulos, N.; Canepa, E.; Tedeschi, G.; Prati, P.; Zarmpas, P.; Bastianini, M.; Missamou, T.; Cavaleri, L.

    2016-05-01

    Aerosol particles in coastal areas result from a complex mixing between sea spray aerosols locally generated at the sea surface by the wind-waves interaction processes and a continental component resulting from natural and/or anthropogenic sources. This paper presents a physical and chemical analysis of the aerosol data acquired from May to September 2014 in the Adriatic Sea. Aerosol distributions were measured on the Acqua Alta platform located 15 km off the coast of Venice using two Particle Measuring System probes and a chemical characterization was made using an Ion Chromatography analysis (IC). Our aim is to study both the sea-spray contribution and the anthropogenic influence in the coastal aerosol of this Mediterranean region. To this end, we focus on a comparison between the present data and the aerosol size distributions measured south of the French Mediterranean coast. For air masses of marine origin transported by southern winds on the French coast and by the Sirocco in the Adriatic, we note a good agreement between the concentrations of super-micrometer aerosols measured in the two locations. This indicates a similar sea surface production of sea-spray aerosols formed by bubble bursting processes in the two locations. In contrast, the results show larger concentrations of submicron particles in the North-Western Mediterranean compared to the Adriatic, which result probably from a larger anthropogenic background for marine conditions. In contrast, for a coastal influence, the chemical analysis presented in the present paper seems to indicate a larger importance of the anthropogenic impact in the Northern Adriatic compared to the North-Western Mediterranean.

  5. February 2003 marine atmospheric conditions and the bora over the northern Adriatic

    USGS Publications Warehouse

    Dorman, C.E.; Carniel, S.; Cavaleri, L.; Sclavo, M.; Chiggiato, J.; Doyle, J.; Haack, T.; Pullen, J.; Grbec, B.; Vilibic, I.; Janekovic, I.; Lee, C.; Malacic, V.; Orlic, M.; Paschini, E.; Russo, A.; Signell, R.P.

    2007-01-01

    A winter oceanographic field experiment provided an opportunity to examine the atmospheric marine conditions over the northern Adriatic. Mean February winds are from a northeasterly direction over most of the Adriatic and a more northerly direction along the western coast. Wind speeds are fastest in jets over the NE coast during bora events and weakest in the mid-northwestern Adriatic. Diurnal air temperature cycles are smallest on the NE coast and largest in the midwestern Adriatic. The maximum sea-air difference is +10??C on the eastern coast and near zero on the midwestern Adriatic. Boras are northeasterly (from) wind events that sweep off Croatia and Slovenia, bringing slightly colder and drier air over the northern Adriatic. The main bora season is December to March. Winter 2002-2003 was normal for bora events. Synoptic-scale temporal variations are correlated over the northern Adriatic. Fastest Bora winds and highest wind stress over the northern Adriatic is concentrated in four topographically controlled jets. The strongest is the Senj Jet, while the Trieste Jet extends across the entire northern Adriatic. Between each two jets is a weak wind zone. The greatest mean net heat loss is in bora jets in the NE Adriatic, where it was -438 W m-2 and is weakest in the midwestern northern Adriatic, where it was near zero. Wind stress is concentrated over the NE half of Adriatic in four bora jets, while wind stress is weak in the NW Adriatic. There is significant variation in wind stress mean and standard deviation structure over the northern Adriatic with each bora event. Copyright 2006 by the American Geophysical Union.

  6. Processes influencing seasonal hypoxia in the northern California Current System

    PubMed Central

    Connolly, T. P.; Hickey, B. M.; Geier, S. L.; Cochlan, W. P.

    2010-01-01

    This paper delineates the role of physical and biological processes contributing to hypoxia, dissolved oxygen (DO) < 1.4 mL/L, over the continental shelf of Washington State in the northern portion of the California Current System (CCS). In the historical record (1950–1986) during the summer upwelling season, hypoxia is more prevalent and severe off Washington than further south off northern Oregon. Recent data (2003–2005) show that hypoxia over the Washington shelf occurred at levels previously observed in the historical data. 2006 was an exception, with hypoxia covering ~5000 km2 of the Washington continental shelf and DO concentrations below 0.5 mL/L at the inner shelf, lower than any known previous observations at that location. In the four years studied, upwelling of low DO water and changes in source water contribute to interannual variability, but cannot account for seasonal decreases below hypoxic concentrations. Deficits of DO along salinity surfaces, indicating biochemical consumption of DO, vary significantly between surveys, accounting for additional decreases of 0.5–2.5 mL/L by late summer. DO consumption is associated with denitrification, an indicator of biochemical sediment processes. Mass balances of DO and nitrate show that biochemical processes in the water column and sediments each contribute ~50% to the total consumption of DO in near-bottom water. At shorter than seasonal time scales on the inner shelf, along-shelf advection of hypoxic patches and cross-shelf advection of seasonal gradients are both shown to be important, changing DO concentrations by 1.5 mL/L or more over five days. PMID:20463844

  7. Parental influence on obesity in Northern Plains American Indian youth.

    PubMed

    Ricci, Christiana L; Brown, Blakely D; Noonan, Curtis; Harris, Kari Jo; Dybdal, Laura; Parker, Martin; Gress, Shannon

    2012-01-01

    Little is known regarding American Indian (AI) parental influence on children's diet and physical activity (PA), or if this influence is associated with childhood weight. We compared AI parents' diet, PA, and support for these behaviors with the child's body mass index. Scores for parental support of positive PA and diet were higher among parents of overweight/obese children. Parent PA and nutrition behaviors were in a similar, but not significant, direction with respect to child body mass index. Findings suggest that future research is needed to determine what parental, societal, or community variables influence AI children to engage in healthy eating and PA, especially if they are overweight or obese, and the age at which these variables would have the most impact on these behaviors. PMID:22143489

  8. Cues of maternal condition influence offspring selfishness.

    PubMed

    Wong, Janine W Y; Lucas, Christophe; Kölliker, Mathias

    2014-01-01

    The evolution of parent-offspring communication was mostly studied from the perspective of parents responding to begging signals conveying information about offspring condition. Parents should respond to begging because of the differential fitness returns obtained from their investment in offspring that differ in condition. For analogous reasons, offspring should adjust their behavior to cues/signals of parental condition: parents that differ in condition pay differential costs of care and, hence, should provide different amounts of food. In this study, we experimentally tested in the European earwig (Forficula auricularia) if cues of maternal condition affect offspring behavior in terms of sibling cannibalism. We experimentally manipulated female condition by providing them with different amounts of food, kept nymph condition constant, allowed for nymph exposure to chemical maternal cues over extended time, quantified nymph survival (deaths being due to cannibalism) and extracted and analyzed the females' cuticular hydrocarbons (CHC). Nymph survival was significantly affected by chemical cues of maternal condition, and this effect depended on the timing of breeding. Cues of poor maternal condition enhanced nymph survival in early broods, but reduced nymph survival in late broods, and vice versa for cues of good condition. Furthermore, female condition affected the quantitative composition of their CHC profile which in turn predicted nymph survival patterns. Thus, earwig offspring are sensitive to chemical cues of maternal condition and nymphs from early and late broods show opposite reactions to the same chemical cues. Together with former evidence on maternal sensitivities to condition-dependent nymph chemical cues, our study shows context-dependent reciprocal information exchange about condition between earwig mothers and their offspring, potentially mediated by cuticular hydrocarbons. PMID:24498046

  9. Oceanographic Conditions Off Northern Chile During the 1996 La Nina and 1997-1998 El Nino: Part1 - Hydrographic Conditions

    NASA Technical Reports Server (NTRS)

    Blanco, J.; Thomas, A.; Strub, T.; Carr, M.

    2000-01-01

    The evolution of oceanographic conditions in the upwelling region off northern Chile (18(sup o) - 24(sup o)S) betweeen 1996 and 1998 (including 1997-1998 El Nino) is presented using hydrographic measurements acquired on quarterly cruises of the Chilean Fisheries Institute, sea-surface temperature (SST), sea level, and wind speeds from Arica (18.5(sup o)S), Iquique (20.5(sup o)S), and Antofagasta (23.5(sup o)S), and a time series of vertical temperature profiles off Iquique.

  10. Pore Size Distribution and Methane Equilibrium Conditions at Walker Ridge Block 313, Northern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Bihani, A. D.; Daigle, H.; Cook, A.; Glosser, D.; Shushtarian, A.

    2015-12-01

    Coexistence of three methane phases (liquid (L), gas (G), hydrate (H)) in marine gas hydrate systems may occur according to in-situ pressure, temperature, salinity and pore size. In sediments with salinity close to seawater, a discrete zone of three-phase (3P) equilibrium may occur near the base of the regional hydrate stability zone (RHSZ) due to capillary effects. The existence of a 3P zone influences the location of the bottom-simulating reflection (BSR) and has implications for methane fluxes at the base of the RHSZ. We studied hydrate stability conditions in two wells, WR313-G and WR313-H, at Walker Ridge Block 313 in the northern Gulf of Mexico. We determined pore size distributions (PSD) by constructing a synthetic nuclear magnetic resonance (NMR) relaxation time distribution. Correlations were obtained by non-linear regression on NMR, gamma ray, and bulk density logs from well KC-151 at Keathley Canyon. The correlations enabled construction of relaxation time distributions for WR313-G and WR313-H, which were used to predict PSD through comparison with mercury injection capillary pressure measurements. With the computed PSD, L+H and L+G methane solubility was determined from in-situ pressure and temperature. The intersection of the L+G and L+H curves for various pore sizes allowed calculation of the depth range of the 3P equilibrium zone. As in previous studies at Blake Ridge and Hydrate Ridge, the top of the 3P zone moves upwards with increasing water depth and overlies the bulk 3P equilibrium depth. In clays at Walker Ridge, the predicted thickness of the 3P zone is approximately 35 m, but in coarse sands it is only a few meters due to the difference in absolute pore sizes and the width of the PSD. The thick 3P zone in the clays may explain in part why the BSR is only observed in the sand layers at Walker Ridge, although other factors may influence the presence or absence of a BSR.

  11. Pore size distribution and methane equilibrium conditions at Walker Ridge Block 313, northern Gulf of Mexico

    SciTech Connect

    Bihani, Abhishek; Daigle, Hugh; Cook, Ann; Glosser, Deborah; Shushtarian, Arash

    2015-12-15

    Coexistence of three methane phases (liquid (L), gas (G), hydrate (H)) in marine gas hydrate systems may occur according to in-situ pressure, temperature, salinity and pore size. In sediments with salinity close to seawater, a discrete zone of three-phase (3P) equilibrium may occur near the base of the regional hydrate stability zone (RHSZ) due to capillary effects. The existence of a 3P zone influences the location of the bottom-simulating reflection (BSR) and has implications for methane fluxes at the base of the RHSZ. We studied hydrate stability conditions in two wells, WR313-G and WR313-H, at Walker Ridge Block 313 in the northern Gulf of Mexico. We determined pore size distributions (PSD) by constructing a synthetic nuclear magnetic resonance (NMR) relaxation time distribution. Correlations were obtained by non-linear regression on NMR, gamma ray, and bulk density logs from well KC-151 at Keathley Canyon. The correlations enabled construction of relaxation time distributions for WR313-G and WR313-H, which were used to predict PSD through comparison with mercury injection capillary pressure measurements. With the computed PSD, L+H and L+G methane solubility was determined from in-situ pressure and temperature. The intersection of the L+G and L+H curves for various pore sizes allowed calculation of the depth range of the 3P equilibrium zone. As in previous studies at Blake Ridge and Hydrate Ridge, the top of the 3P zone moves upwards with increasing water depth and overlies the bulk 3P equilibrium depth. In clays at Walker Ridge, the predicted thickness of the 3P zone is approximately 35 m, but in coarse sands it is only a few meters due to the difference in absolute pore sizes and the width of the PSD. The thick 3P zone in the clays may explain in part why the BSR is only observed in the sand layers at Walker Ridge, although other factors may influence the presence or absence of a BSR.

  12. Comparison of survival patterns of northern and southern genotypes of the North American tick Ixodes scapularis (Acari: Ixodidae) under northern and southern conditions

    USGS Publications Warehouse

    Ginsberg, Howard S.; Rulison, Eric L.; Azevedo, Alexandra; Pang, Genevieve C.; Kuczaj, Isis M.; Tsao, Jean I.; LeBrun, Roger A.

    2014-01-01

    Conclusions: Our results suggest that conditions in southern North America are less hospitable than in the north to populations of I. scapularis. Southern conditions might have resulted in ecological or behavioral adaptations that contribute to the relative rarity of I. scapularis borne diseases, such as Lyme borreliosis, in the southern compared to the northern United States.

  13. Comparison of survival patterns of northern and southern genotypes of the North American tick Ixodes scapularis (Acari: Ixodidae) under northern and southern conditions

    USGS Publications Warehouse

    Ginsberg, Howard S.; Rulison, Eric L.; Azevedo, Alexandra; Pang, Genevieve C.; Kuczaj, Isis M.; Tsao, Jean I.; LeBrun, Roger A.

    2014-01-01

    Our results suggest that conditions in southern North America are less hospitable than in the north to populations of I. scapularis. Southern conditions might have resulted in ecological or behavioral adaptations that contribute to the relative rarity of I. scapularis borne diseases, such as Lyme borreliosis, in the southern compared to the northern United States.

  14. Influence of atmospheric stability and transport on CH4 concentrations in northern Spain.

    PubMed

    García, M Ángeles; Sánchez, M Luisa; Pérez, Isidro A; Ozores, Marta I; Pardo, Nuria

    2016-04-15

    Continuous methane (CH4) concentrations were measured in Northern Spain over two years (2011-2012) by multi-point sampling at 1.8, 3.7 and 8.3m using a Picarro analyser. The technique is based on cavity ring-down spectroscopy. The contrast in mean concentrations was about 1.2ppb, with 95th percentiles differing by 2.2ppb and mean minimum concentrations proving similar. Temporal variations of CH4 were also analysed, with a similar seasonal variability being found for the three heights. The highest CH4 concentrations were obtained in late autumn and winter and the lowest in summer, yielding a range of 52ppb. This variation may depend on the active photochemical reaction with OH radical during a period of intense solar radiation and changes in soil conditions together with variations in emissions. Peak concentration levels were recorded at night-time, between 5:00-7:00 GMT, with mean values ranging between 1920 and 1923ppb. The lowest value, around 1884ppb, was obtained at 16:00 GMT. This diurnal variation was mainly related to vertical mixing and photochemistry. Therefore, CH4 concentrations were also examined using the bulk Richardson number (RB) as a stability indicator. Four groups were distinguished: unstable cases, situations with pure shear flow, transitional stages and drainage flows. The highest contrast in mean CH4 concentrations between lower and upper heights was obtained for the transition and drainage cases, mainly associated to high concentrations from nearby sources. The impact of long range transport was analysed by means of 3-day isobaric backward air mass trajectories, which were calculated taking into account origins from Europe, Africa, the Atlantic Ocean and Local conditions. Assessment of the results showed the influence of S and SE wind sectors, especially with Local conditions associated with low winds. Finally, an estimation of the background CH4 concentration in the study period provided an average value of about 1892ppb. PMID:26815292

  15. Late attainment of full Holocene interglacial conditions in the northern North Atlantic

    NASA Astrophysics Data System (ADS)

    de Vernal, Anne; Hillaire-Marcel, Claude; Van Nieuwenhove, Nicolas; Fréchette, Bianca; Gibb, Olivia; Ouellet-Bernier, Marie-Michèle

    2015-04-01

    The postglacial changes in sea surface conditions were reconstructed in more than 30 cores from the northern North Atlantic and subarctic seas based on the modern analogue technique applied to dinocyst assemblages. The reconstructed parameters include winter and summer sea-surface temperature (SST) and salinity (SSS) in addition to sea-ice cover, thus allowing assessment of surface density and seasonal contrast of climate. Results illustrate important changes in sea-surface conditions through the early to mid-Holocene transition. Despite differences in timing and amplitude, the overall data point to the persistence of strong east to west gradients and to a late attainment of "optimum" conditions. In the western part of the basin (northern Labrador Sea, Baffin Bay, eastern Greenland margins), a main change is marked by an increase in salinity and a decrease in the seasonal contrast of temperature from 7.5 ka BP. In several of the study cores, the isotopic composition (18O and 13C) of planktic foraminifers (N. pachyderma left-coiled) provides complementary information on subsurface conditions. By combining the information from dinocyst and isotope proxies, it was possible to calibrate potential density vs calcite-18O relationships, and therefore to calculate density gradients from surface to sub-surface water masses, along the pycnocline. Paleo-density gradients also illustrate east to west differences and reveal conditions unfavorable to vertical convection after 7.5 ka BP if not later in the Labrador Sea, and about 6.5 ka in the western Nordic Seas.

  16. Rare earth elements in coastal sediments of the northern Galician shelf: Influence of geological features

    NASA Astrophysics Data System (ADS)

    Prego, Ricardo; Caetano, Miguel; Bernárdez, Patricia; Brito, Pedro; Ospina-Alvarez, Natalia; Vale, Carlos

    2012-03-01

    The Northern coast of Galicia, NW Iberian Peninsula, exhibits a variety of geological features: Ortegal allochthonous complex, Ollo-de-Sapo autochthonous domain and massifs of Bares, Barqueiro and San-Ciprian. In order to examine the influence of terrestrial lithologies on coastal sediments, 103 samples were collected in the Rias of Ortigueira, Barqueiro and Viveiro, their neighbouring shelf and the estuaries of Mera, Sor and Landro rivers. Aluminium, Fe, Sc, particulate inorganic and organic carbon and rare earth elements (REE) were determined in the <2 mm fraction. In addition, calcite, muscovite, quartz and riebeckite minerals were identified and quantified in 33 selected samples. The distributions of riebeckite and Fe reflect the influence of Ortegal complex on the coastal areas around the Cape Ortegal. The highest concentrations of ΣREE were found in fine sediments from confined inner parts of the Rias (up to 233 mg kg-1), while most of the sands contained 11-70 mg kg-1. ΣREE normalised to European Shale (ES) highlights the relative abundance of lanthanides (ΣREEN>6) near Cape Ortegal and the innermost ria zones. The ratio between light and heavy REE (L/H) showed lower values (4-11) around Cape Ortegal and the shelf while higher ratios (15-23) were detected in west of the Cape Estaca-de-Bares and in the inner Viveiro Ria due to elevated contributions of La and Ce. The L/H values normalised to ES reflects the importance of HREE in the adjacent area to Ortegal Complex (LN/HN<0.8) and the LREE (LN/HN>1.4) in the inner estuaries and west Cape Estaca-de-Bares. The highest REE individual ES normalised were measured in fine-grained sediments of the Mera and Sor estuaries. Sediments from the eastern shelf of Cape Ortegal presented enhanced ratios only for HREE. These results indicate that distribution of REE in the northern Galician region is highly depending on the neighbouring lithological pattern, contrasting with the situation found in the western Galician

  17. Childhood Conditions Influence Adult Progesterone Levels

    PubMed Central

    Núñez-de la Mora, Alejandra; Chatterton, Robert T; Choudhury, Osul A; Napolitano, Dora A; Bentley, Gillian R

    2007-01-01

    Background Average profiles of salivary progesterone in women vary significantly at the inter- and intrapopulation level as a function of age and acute energetic conditions related to energy intake, energy expenditure, or a combination of both. In addition to acute stressors, baseline progesterone levels differ among populations. The causes of such chronic differences are not well understood, but it has been hypothesised that they may result from varying tempos of growth and maturation and, by implication, from diverse environmental conditions encountered during childhood and adolescence. Methods and Findings To test this hypothesis, we conducted a migrant study among first- and second-generation Bangladeshi women aged 19–39 who migrated to London, UK at different points in the life-course, women still resident in Bangladesh, and women of European descent living in neighbourhoods similar to those of the migrants in London (total n = 227). Data collected included saliva samples for radioimmunoassay of progesterone, anthropometrics, and information from questionnaires on diet, lifestyle, and health. Results from multiple linear regression, controlled for anthropometric and reproductive variables, show that women who spend their childhood in conditions of low energy expenditure, stable energy intake, good sanitation, low immune challenges, and good health care in the UK have up to 103% higher levels of salivary progesterone and an earlier maturation than women who develop in less optimal conditions in Sylhet, Bangladesh (F9,178 = 5.05, p < 0.001, standard error of the mean = 0.32; adjusted R2 = 0.16). Our results point to the period prior to puberty as a sensitive phase when changes in environmental conditions positively impact developmental tempos such as menarcheal age (F2,81 = 3.21, p = 0.03) and patterns of ovarian function as measured using salivary progesterone (F2,81 = 3.14, p = 0.04). Conclusions This research demonstrates that human females use an extended

  18. When does relational information influence evaluative conditioning?

    PubMed

    Zanon, Riccardo; De Houwer, Jan; Gast, Anne; Smith, Colin Tucker

    2014-01-01

    Building on the intriguing findings of Peters and Gawronski (2011, Experiment 3), we examined the conditions under which relational information (i.e., information about how two stimuli are related) moderates evaluative conditioning (EC; i.e., the effect of stimulus pairing on liking). In Experiment 1, participants saw stimulus pairs that consisted of a novel nonword (conditioned stimulus; CS) and a known positive or negative word (unconditioned stimulus; US). Before or after the pairings, participants were told that the nonword had the opposite meaning to the word with which it was paired. Subsequent measures of the implicit evaluation of the nonwords revealed that nonwords paired with positive words were liked less than nonwords paired with negative words, but only when the relational information was presented before the CS-US pairings. In a second experiment, participants were first informed that the CS and US of each pair were related in one way (e.g., that they have the same meaning). Afterwards, this information was either confirmed (e.g., that they indeed have the same meaning) or reversed (e.g., that they actually have an opposite meaning). Whereas the first relational information had more impact on implicit evaluations than on explicit evaluations, the reverse was true for the second relational information. Moreover, informing participants that CS and US were equivalent produced the same effects as pairing CS and US without providing explicit relational information, thus suggesting that the mere co-occurrence of CS and US is treated as a cue for equivalence of CS and US. Implications for mental process models of EC are discussed. PMID:24670104

  19. Relationship between Prevailing Oceanographic conditions on the fishing operations in the Northern Indian Ocean

    NASA Astrophysics Data System (ADS)

    Moazzam Khan, Muhammad

    2014-05-01

    Marked seasonality in fishing operation and catch composition was observed in the Northern Indian Ocean. These variations are more pronounced and noticeable in case of trawling for fish and shrimp as well as in the surface gillnetting for tuna and large pelagics. Although oceanographic conditions of the Northern Indian Ocean has been studied comprehensively, some facets of these are not well understood especially their relation with the fish distribution and abundance. Important oceanographic factors especially migration of oxygen minimum layer towards coastal areas after the cessation of South-West Monsoon seems to the most important factor responsible for the seasonal variation in the fishing intensity and species composition. Distribution and abundance of some of the commercially important marine animals especially billfishes was observed to be associated with the physical features of the area especially their abundance was noticed along continental margin and on the ridges in the Arabian Sea. The paper describes seasonal variation in abundance and catch composition of various fishing operations in the Indian Ocean and relates its to prevailing oceanographic conditions. Fishermen traditional knowledge about the seasonality of these conditions is also documented in the paper.

  20. Garnet lherzolite xenoliths in the kimberlites of northern Lesotho: revised P-T equilibration conditions and upper mantle Palaeogeotherm

    NASA Astrophysics Data System (ADS)

    Carswell, D. A.; Gibb, F. G. F.

    1987-12-01

    Evidence is presented that the inflected palaeogeotherm for northern Lesotho, previously highlighted by Boyd (1973), Boyd and Nixon (1973, 1975), Finnerty and Boyd (1984, 1987), is essentially an artifact of the unsatisfactory, over-simplified barometer formulation (based on MacGregor 1974) employed. The absence of an inflection in the palaeogeotherm for Udachnaya, Siberia based on P-T estimates for garnet lherzolite xenoliths calculated with the same barometer, does not prove the reality of an inflected palaeogeotherm for northern Lesotho. Rather, it reflects, at least in part, chemical differences between the equivalent deformed, high- T xenoliths in these two areas — most importantly expressed in the respective contents of Jadeite relative to ureyite in the constituent orthopyroxenes. Accurate estimation of P-T equilibration conditions for garnet lherzolite xenoliths requires both complete and precise mineral analyses and adequate consideration of the influence of minor elements, such as Cr and Na, on the element exchange reaction thermometers and barometers employed. The barometer formulation of Nickel and Green (1985) is judged to be the best currently available. As no single thermometer is entirely satisfactory and dependable throughout the P-T range of interest, equilibration temperatures are currently best assessed as a mean value obtained from application of the most accurate formulations for both the two-pyroxene solvus thermometer (Bertrand and Mercier 1985) and Fe2+-Mg2+ exchange reactions between garnet-clinopyroxene (Powell 1985), garnet-orthopyroxene (Harley 1984a) and garnet-olivine (O'Neill and Wood 1979) mineral pairs. Such ‘best’ P-T estimates for xenoliths in the kimberlites of northern Lesotho indicate a somewhat elevated, non-inflected, upper mantle palaeogeotherm, compatible with a 120 145 km thick thermally conductive lithosphere above a convecting asthenosphere. The common coarse textured, chemically depleted, garnet lherzolite

  1. Influence of weather-climatic conditions on biospheric processes

    NASA Astrophysics Data System (ADS)

    Govorushko, S. M.

    2012-12-01

    The significance of meteorological processes and phenomena in the biosphere functioning is revealed. The influence of various weather conditions on human health is considered; the factors and mechanisms of their action are described. The impact of meteorological processes on animals is discussed and concrete examples of such impacts are presented. The influence of meteorological processes and phenomena on plants at different stages of their life (pollination, growth, ripening, transport of seeds, damage, and death) and on some abiotic natural components is shown. It is inferred that weather-climatic conditions have a great influence on biospheric processes.

  2. Conditional local influence in case-weights linear regression.

    PubMed

    Poon, W Y; Poon, Y S

    2001-05-01

    The local influence approach proposed by Cook (1986) makes use of the normal curvature and the direction achieving the maximum curvature to assess the local influence of minor perturbation of statistical models. When the approach is applied to the linear regression model, the result provides information concerning the data structure different from that contributed by Cook's distance. One of the main advantages of the local influence approach is its ability to handle the simultaneous effect of several cases, namely, the ability to address the problem of 'masking'. However, Lawrance (1995) points out that there are two notions of 'masking' effects, the joint influence and the conditional influence, which are distinct in nature. The normal curvature and the direction of maximum curvature are capable of addressing effects under the category of joint influences but not conditional influences. We construct a new measure to define and detect conditional local influences and use the linear regression model for illustration. Several reported data sets are used to demonstrate that new information can be revealed by this proposed measure. PMID:11393899

  3. Latitudinal Discontinuity in Thermal Conditions along the Nearshore of Central-Northern Chile

    PubMed Central

    Tapia, Fabian J.; Largier, John L.; Castillo, Manuel; Wieters, Evie A.; Navarrete, Sergio A.

    2014-01-01

    Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30–32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4–10 years at 15 sites between 28–35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30–31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30–31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species

  4. Latitudinal discontinuity in thermal conditions along the nearshore of central-northern Chile.

    PubMed

    Tapia, Fabian J; Largier, John L; Castillo, Manuel; Wieters, Evie A; Navarrete, Sergio A

    2014-01-01

    Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30-32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4-10 years at 15 sites between 28-35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30-31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30-31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species

  5. Ecosystem dynamics of the Pacific-influenced Northern Bering and Chukchi Seas in the Amerasian Arctic

    NASA Astrophysics Data System (ADS)

    Grebmeier, Jacqueline M.; Cooper, Lee W.; Feder, Howard M.; Sirenko, Boris I.

    2006-10-01

    The shallow continental shelves and slope of the Amerasian Arctic are strongly influenced by nutrient-rich Pacific waters advected over the shelves from the northern Bering Sea into the Arctic Ocean. These high-latitude shelf systems are highly productive both as the ice melts and during the open-water period. The duration and extent of seasonal sea ice, seawater temperature and water mass structure are critical controls on water column production, organic carbon cycling and pelagic-benthic coupling. Short food chains and shallow depths are characteristic of high productivity areas in this region, so changes in lower trophic levels can impact higher trophic organisms rapidly, including pelagic- and benthic-feeding marine mammals and seabirds. Subsistence harvesting of many of these animals is locally important for human consumption. The vulnerability of the ecosystem to environmental change is thought to be high, particularly as sea ice extent declines and seawater warms. In this review, we focus on ecosystem dynamics in the northern Bering and Chukchi Seas, with a more limited discussion of the adjoining Pacific-influenced eastern section of the East Siberian Sea and the western section of the Beaufort Sea. Both primary and secondary production are enhanced in specific regions that we discuss here, with the northern Bering and Chukchi Seas sustaining some of the highest water column production and benthic faunal soft-bottom biomass in the world ocean. In addition, these organic carbon-rich Pacific waters are periodically advected into low productivity regions of the nearshore northern Bering, Chukchi and Beaufort Seas off Alaska and sometimes into the East Siberian Sea, all of which have lower productivity on an annual basis. Thus, these near shore areas are intimately tied to nutrients and advected particulate organic carbon from the Pacific influenced Bering Shelf-Anadyr water. Given the short food chains and dependence of many apex predators on sea ice, recent

  6. The impact of oral conditions on children in England, Wales and Northern Ireland 2013.

    PubMed

    Ravaghi, V; Holmes, R D; Steele, J G; Tsakos, G

    2016-08-26

    Background The 2013 Children's Dental Health survey is the fifth in a series of national surveys.Aim To summarise key findings on oral health perceptions, oral symptoms, and the impacts of oral conditions on the daily life of children and their families.Methodology A representative sample of children (aged 5, 8 12 and 15 years) and their parents in England, Wales and Northern Ireland completed relevant questionnaires.Results Oral symptoms, even more profound ones such as toothache, were prevalent among all age groups. Overall, 58% of 12- and 45% of 15-year-olds reported at least one oral impact in the past three months. The most prevalent oral impact was feeling embarrassed to smile or laugh, followed by difficulty eating. These symptoms and oral impacts were disproportionately high among children eligible for free school meals. Furthermore, one fifth to one third of parents reported that their children's oral conditions had some impact on their family life.Conclusion Oral symptoms were common and oral conditions had a negative impact on the quality of life of large proportions of children. There were clear and marked socioeconomic inequalities, with considerably worse oral health perceptions and higher levels of oral impacts among the more deprived children. PMID:27561577

  7. Northern-Hemisphere snow cover patterns and formation conditions in winter 2007 and 2012

    NASA Astrophysics Data System (ADS)

    Cui, Hongyan; Qiao, Fangli; Shu, Qi; Yu, Long

    2016-06-01

    The Arctic sea ice minimum records appeared in the Septembers of 2007 and 2012, followed by high snow cover areas in the Northern Hemisphere winters. The snow cover distributions show different spatial patterns in these two years: increased snow cover in Central Asia and Central North America in 2007, while increased snow cover in East Asia and northwestern Europe in 2012. The high snow cover anomaly shifted to higher latitudes in winter of 2012 compared to 2007. It is noticed that the snow cover had positive anomaly in 2007 and 2012 with the following conditions: the negative geopotential height and the related cyclonic wind anomaly were favorable for upwelling, and, with the above conditions, the low troposphere and surface air temperature anomaly and water vapor anomaly were favorable for the formation and maintenance of snowfalls. The negative geopotential height, cyclonic wind and low air temperature conditions were satisfied in different locations in 2007 and 2012, resulting in different spatial snow cover patterns. The cross section of lower air temperature move to higher latitudes in winter of 2012 compared to 2007.

  8. Influencing and Facilitating Conditions for Developing Reflective Assessment Practice

    ERIC Educational Resources Information Center

    Rønsen, Anne Kristin; Smith, Kari

    2014-01-01

    By following a professional development project focusing on enhancing assessment competence amongst teachers, the current study examines how teachers use reflective writing and systematic discussions as tools for developing competence in assessment. More specifically, the article aims at identifying conditions that influence and facilitate…

  9. Influence of soil conditioning on ground deformation during longitudinal tunneling

    NASA Astrophysics Data System (ADS)

    Jiang, Mingjing; Yin, Zhen-Yu

    2014-03-01

    Soil conditioning is often adopted to facilitate EPB shield tunneling. However, the resulting improvement of soil fluidity and the reduction of friction forces will also raise the ground deformation problem. This paper aims to investigate the influence of soil conditioning on the ground deformation during longitudinal tunneling. DEM is employed for this study due to its advantages in analyzing large deformations and discontinuous processes. Soil conditioning is modeled by reducing the interparticle friction of soils in a specific zone around the cutterhead of the tunnel. The tunnel advance with different soil-conditioning treatments is thus modeled. Comparisons are carried out on the ground deformation, i.e. ground surface settlement, vertical and horizontal displacements. The influence of soil conditioning on the ground deformation is clarified, and is associated with the fluidity from poor to favorite, and the mechanical properties from dilative to contractive are associated with the increase of soil conditioning. The results are helpful to determine the conditioned soils and control ground deformation for real constructions.

  10. DISTRIBUTION AND COMPOSITION OF DISSOLVED AND PARTICULATE ORGANIC CARBON IN NORTHERN SAN FRANCISCO BAY DURING LOW FRESHWATER FLOW CONDITIONS

    EPA Science Inventory

    The distribution of dissolved and particulate organic matter was studied in northern San Francisco Bay on seven dates during declining flow conditions from April to October 1996. Measurements were made at 3 to 11 stations (usually 8) along the salinity gradient from the Sacrament...

  11. Population dynamics of a northern-adapted mammal: disentangling the influence of predation and climate change.

    PubMed

    Pokallus, John W; Pauli, Jonathan N

    2015-09-01

    Community structure and interspecific interactions are particularly vulnerable to rapidly changing climatic regimes. Recent changes in both climate and vertebrate community assemblages have created a unique opportunity to examine the impacts of two dynamic forces on population regulation. We examined the effects of warming winter conditions and the reestablishment of a previously extirpated predator, the fisher (Martes pennanti), on regulatory mechanisms in a northern-adapted mammal, the porcupine (Erethizon dorsatum), along their southern range boundary. Using a long-term (17-year) capture-recapture data set, we (1) quantified the impacts of climate change and increased fisher predation on the survival of adult porcupines at their regional southern terminus, (2) assessed recruitment (via both adult fecundity and juvenile survival) of porcupines, and (3) modeled the relative importance of predation and winter conditions on the demography and population growth rate (λ). Severe winters and abundant predators interacted synergistically to reduce adult survivorship by as much as 44%, while expanding predator populations led to near reproductive failure among porcupines. Increasing predatory pressure, disruptions in this community module, and more frequent extreme winter weather events led to predicted extirpation within 50 years, whereas in the absence of predators, the population was viable. Our results provide a mechanistic understanding behind distributional shifts resulting from climate change and may be broadly relevant for predicting future distributional shifts in other northern-adapted mammalian species. PMID:26552263

  12. Air- ice-snow interaction in the Northern Hemisphere under different stability conditions

    NASA Astrophysics Data System (ADS)

    Repina, Irina; Chechin, Dmitry; Artamonov, Arseny

    2013-04-01

    even high latitudes of the Northern Hemisphere because the stable conditions above Arctic ice field dominate. Under such conditions the air flow over the uneven surface behaves in the way it does over the even one. This happens because depressions between ridges are filled with heavier air up to the height of irreguralities. As a result, the air moves at the level of ridges without entering depressions. Increased heat and mass transfer over polynyas and leads through self-organization of turbulent convection is found. The work was sponsored by RFBR grants and funded by the Government of the Russian Federation grants.

  13. Ecology of cultivable yeasts in pristine forests in northern Patagonia (Argentina) influenced by different environmental factors.

    PubMed

    Mestre, María Cecilia; Fontenla, Sonia; Rosa, Carlos A

    2014-06-01

    Environmental factors influencing the occurrence and community structure of soil yeasts in forests are not well studied. There are few studies dedicated to Southern Hemisphere soil yeasts populations and even fewer focused on temperate forests influenced by volcanic activity. The present work aimed to study the ecology of soil yeast communities from pristine forests influenced by different environmental factors (precipitation, physicochemical properties of soil, tree species, soil region, and season). The survey was performed in 4 northern Patagonian forests: 2 dominated by Nothofagus pumilio and 2 by Nothofagus antarctica. Yeast communities were described with ecological indices and species accumulation curves, and their association with environmental characteristics was assessed using multivariate analysis. Each forest site showed a particular arrangement of species as a result of environmental characteristics, such as dominant plant species, nutrient availability, and climatic characteristics. Cryptococcus podzolicus was most frequently isolated in nutrient-rich soils, Trichosporon porosum dominated cold mountain forests with low nutrient and water availability in soil, and capsulated yeasts such as Cryptococcus phenolicus dominated forest sites with low precipitation. The present work suggests that environmental factors affecting yeast communities may not be the current soil characteristics but the result of complex interactions of factors including natural disturbances like volcanic activity. PMID:24849380

  14. Environmental conditions influence tissue regeneration rates in scleractinian corals.

    PubMed

    Sabine, Alexis M; Smith, Tyler B; Williams, Dana E; Brandt, Marilyn E

    2015-06-15

    Natural and anthropogenic factors may influence corals' ability to recover from partial mortality. To examine how environmental conditions affect lesion healing, we assessed several water quality parameters and tissue regeneration rates in corals at six reefs around St. Thomas, US Virgin Islands. We hypothesized that sites closer to developed areas would have poor water quality due to proximity to anthropogenic stresses, which would impede tissue regeneration. We found that water flow and turbidity most strongly influenced lesion recovery rates. The most impacted site, with high turbidity and low flow, recovered almost three times slower than the least impacted site, with low turbidity, high flow, and low levels of anthropogenic disturbance. Our results illustrate that in addition to lesion-specific factors known to affect tissue regeneration, environmental conditions can also control corals' healing rates. Resource managers can use this information to protect low-flow, turbid nearshore reefs by minimizing sources of anthropogenic stress. PMID:25982415

  15. Working in hot conditions--a study of electrical utility workers in the northern territory of Australia.

    PubMed

    Brearley, Matt; Harrington, Phillip; Lee, Doug; Taylor, Raymond

    2015-01-01

    Environmental conditions of Australia's Northern Territory are seasonally conducive to excessive body heat storage by outdoor workers. For electrical utility workers who periodically work at height, in confined space, and in proximity to live power sources, the impact of the climate may be considered a hazardous condition. Therefore, this study examined the physiological and fluid balance responses of 20 power network workers (31.5 years; 86.0 kg; 1.71 m; BMI 29.5) throughout work shifts in the Northern and Southern regions of the Northern Territory, Australia. Twenty male heat-acclimatized power network workers provided written informed consent to be monitored during maintenance of electrical infrastructure that included replacing power pole components and transformer and substation repairs in the Northern (n = 13) and Southern regions (n = 7) of the Northern Territory (mean wet-bulb globe temperatures of 32.0°C and 28.7°C, respectively). An ingestible telemetry pill provided measurement of gastrointestinal temperature (Tgi), that when combined with heart rate values, provided physiological strain index (PSI). Urine specific gravity, sweat rate, and level of dehydration were also determined. The Tgi values of this study were within the ISO9886 limit for monitored, heat-acclimatized workers, with a peak of 38.4°C. Mean PSI was 2.6, which represents overall low strain, with periods of moderate strain. Urinary analysis indicated that workers were dehydrated prior to and following the work shift, however the mean sweat rate of 0.44 L.h(-1) was matched by fluid consumption of 0.42 L.h(-1) to limit body mass loss to 0.1% during the shift. This study demonstrates that heat acclimatized electrical utility workers adhere to ISO9886 requirements when undertaking self-paced activity in hot conditions. PMID:25265189

  16. Influence of Medical Representatives on Prescribing Practices in Mekelle, Northern Ethiopia

    PubMed Central

    Workneh, Birhanu Demeke; Gebrehiwot, Mehari Gebregergis; Bayo, Tigist Assefa; Gidey, Meles Tekie; Belay, Yared Belete; Tesfaye, Desalegn Mergiaw; Kassa, Terefe Teshome

    2016-01-01

    Background Drug promotion by medical representatives is one of the factors that influence physicians’ prescribing decisions and choice of drugs. Objective To assess the influence of medical representatives on prescribing practice of physicians in health facilities, Mekelle, Northern Ethiopia. Materials and Methods Facility-based cross-sectional study was conducted enrolling all physicians working in public and private health facilities. All public and private health facilities were included and similarly, all physicians rendering services in these facilities were sampled in the study. The data were collected from February to March, 2015. Data were then entered into Epidata Version 3.1 and transferred to STATA version 12 for analysis. Both bivariable and multivariable logistic regressions were used to determine predictors. Results Of the ninety physicians approached in this study, 40 (48.2%) of the physicians believed that their prescribing decisions were influenced by visits of medical representatives (MRs). The odds of physicians who received gifts from MRs being influenced to prescribe their respective products was six times higher than those who reported not accepting any gifts [AOR = 6.56, 95% CI: 2.25, 19.13]. Stationery materials 23(35.4%) and drug samples 20(54.2%) were the commonest kinds of gifts given to physicians and face to face talking 45(54.2%) was the most frequent promotional methods. The finding of this study showed that around thirty-nine percent of MRs have had negative attitude toward competitors’ product. Moreover, working in private health facility was also another predictor of influence of prescribing decision in the study area [AOR = 12.78, 95% CI: 1.31, 124.56]. Conclusion Nearly half of the physicians working in Mekelle reported that their prescribing decisions were influenced by MRs in the last 12 months. Accepting gifts and working in private health facilities were predictors of influencing prescribing decisions. However, most MRs

  17. Influence of a local source of DDT pollution on statewide DDT residues in waterfowl wings, northern Alabama, 1978-79

    USGS Publications Warehouse

    Fleming, W.J.; O'Shea, T.J.

    1980-01-01

    Heavy DDT contamination resulting from a former DDT manufacturing plant in northern Alabama has influenced statewide averages of DDT, DDE, and TDE residues in duck wings tested in the National Pesticide Monitoring Program. In states where contaminant levels in duck wings are high, residue analyses of wings categorized by finer geographic subdivision may be useful in defining the areas of heaviest contamination.

  18. Growth, condition, diet, and consumption rates of northern pike in three Arizona reservoirs

    USGS Publications Warehouse

    Flinders, J.M.; Bonar, Scott A.

    2008-01-01

    Northern pike (Esox lucius L.) introductions are controversial in the western United States due to suspected impacts they might have on established sport fisheries and potential illegal introductions. Tbree Arizona reservoirs, Parker Canyon Lake, Upper Lake Mary and Long Lake were sampled to examine the diet, consumption dynamics, and growth of northern pike. Northern pike diets varied by season and reservoir. In Parker Canyon Lake, diets were dominated by rainbow trout in winter and spring and bluegill and green sunfish in the fall. In Long Lake the northern pike ate crayfish in spring and early summer and switched to young of the year common carp in summer and fall. Black crappie, golden shiners, and crayfish were the major prey in Upper Lake Mary during spring, but they switched to stocked rainbow trout in the fall. Northern pike growth was in the high range of growth reported throughout the United States. Estimated northern pike specific consumption rate (scr) of rainbow trout (g/g/d ?? 10-6) was greatest in Upper Lake Mary (scr = 329.1 ?? 23.7 g/g/d ?? 10-6) where stocked fingerling (280 mm TL) rainbow trout stocked in Long Lake (scr = 1.4 ?? 0.1 g/g/d ?? 10-6) and Parker Canyon Lake (scr = 287.2 ?? 15.1 g/g/d ?? 10-6) where catchable-sized rainbow trout were stocked. Managers should consider the cost-benefits of stocking fish >200 mm TL in lakes containing northern pike. ?? Copyright by the North American Lake Management Society 2008.

  19. The Influence of Rainfall, Vegetation, Elephants and People on Fire Frequency of Miombo Woodlands, Northern Mozambique

    NASA Astrophysics Data System (ADS)

    Ribeiro, N. S.; Okin, G. S.; Shugart, H. H.; Swap, R. J.

    2008-12-01

    Miombo woodlands are important in southern Africa as they occupy over 50% of the land and, their good and services support a large proportion of people in the region. Anthropogenic fires occur in miombo every year especially in the dry season (May - October). This study explores the influence of annual rainfall, elephant density, human density and corridors, and vegetation on the fire frequency. It was carried out in Niassa Reserve located in northern Mozambique, the largest and more pristine conservation area of miombo woodlands in the world. We used a time series analysis and statistical t-test of MODIS-derived Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) to explore the relationship between biomass and fire frequency. The influence of rainfall, elephants, people and vegetation on fire return was explored using a stepwise logistic regression analysis. The results of this study indicate that fire frequency is higher in places with high biomass at beginning of the dry season. In these areas fire seems to be more intense and to strongly reduce biomass in the late dry season. Land cover is the strongest predictor of fire frequency, but elephant density, annual rainfall and human corridors are also important.

  20. The influence of rainfall, vegetation, elephants and people on fire frequency of miombo woodlands, northern Mozambique

    NASA Astrophysics Data System (ADS)

    Ribeiro, N. S.; Okin, G. S.; Shugart, H.; Swap, R.

    2007-12-01

    Miombo woodlands are important in southern Africa as they occupy over 50% of the land and, their good and services support a large proportion of people in the region. Anthropogenic fires occur in miombo every year especially in the dry season (May - October). This study explores the influence of annual rainfall, elephant density, human density and corridors, and vegetation on the fire frequency. It was carried out in Niassa Reserve located in northern Mozambique, the largest and more pristine conservation area of miombo woodlands in the world. We used a time series analysis and statistical t-test of MODIS-derived Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) to explore the relationship between biomass and fire frequency. The influence of rainfall, elephants, people and vegetation on fire return was explored using a stepwise logistic regression analysis. The results of this study indicate that fire frequency is higher in places with high biomass at beginning of the dry season. In these areas fire seems to be more intense and to strongly reduce biomass in the late dry season. Land cover is the strongest predictor of fire frequency, but elephant density, annual rainfall and human corridors are also important.

  1. Conditions for Viral Influence Spreading through Multiplex Correlated Social Networks

    NASA Astrophysics Data System (ADS)

    Hu, Yanqing; Havlin, Shlomo; Makse, Hernán A.

    2014-04-01

    A fundamental problem in network science is to predict how certain individuals are able to initiate new networks to spring up "new ideas." Frequently, these changes in trends are triggered by a few innovators who rapidly impose their ideas through "viral" influence spreading, producing cascades of followers and fragmenting an old network to create a new one. Typical examples include the rise of scientific ideas or abrupt changes in social media, like the rise of Facebook to the detriment of Myspace. How this process arises in practice has not been conclusively demonstrated. Here, we show that a condition for sustaining a viral spreading process is the existence of a multiplex-correlated graph with hidden "influence links." Analytical solutions predict percolation-phase transitions, either abrupt or continuous, where networks are disintegrated through viral cascades of followers, as in empirical data. Our modeling predicts the strict conditions to sustain a large viral spreading via a scaling form of the local correlation function between multilayers, which we also confirm empirically. Ultimately, the theory predicts the conditions for viral cascading in a large class of multiplex networks ranging from social to financial systems and markets.

  2. Influence of maternal dysmetabolic conditions during pregnancy on cardiovascular disease.

    PubMed

    Palinski, Wulf; Nicolaides, Eric; Liguori, Antonio; Napoli, Claudio

    2009-09-01

    Pathogenic factors associated with maternal hypercholesterolemia, obesity, and diabetic conditions during pregnancy influence fetal development and predispose offspring to cardiovascular disease. Animal models have established cause-effect relationships consistent with epidemiological findings in humans and have demonstrated, in principle, that interventions before or during pregnancy can reduce or prevent pathogenic in utero programming. However, little is known about the mechanisms by which maternal dysmetabolic conditions enhance disease susceptibility in offspring. Identification of these mechanisms is rendered more difficult by the fact that programming effects in offspring may be latent and may require conventional risk factors and inherited genetic co-factors to become clinically manifest. Given the increasing prevalence of maternal risk factors, which is expected to lead to a wave of cardiovascular disease in the coming decades, and the length of prospective studies on developmental programming in humans, greater-than-usual emphasis on experimental models and translational studies is necessary. PMID:19655024

  3. Organic Matter Quality and its Influence on Carbon Turnover and Stabilization in Northern Peatlands

    NASA Astrophysics Data System (ADS)

    Turetsky, M. R.; Wieder, R. K.

    2002-12-01

    Peatlands cover 3-5 % of the world's ice-free land area, but store about 33 % of global terrestrial soil carbon. Peat accumulation in northern regions generally is controlled by slow decomposition, which may be limited by cold temperatures and water-logging. Poor organic matter quality also may limit decay, and microbial activity in peatlands likely is regulated by the availability of labile carbon and/or nutrients. Conversely, carbon in recalcitrant soil structures may be chemically protected from microbial decay, particularly in peatlands where carbon can be buried in anaerobic soils. Soil organic matter quality is controlled by plant litter chemical composition and the susceptibility of organic compounds to decomposition through time. There are a number of techniques available for characterizing organic quality, ranging from chemical proximate or elemental analysis to more qualitative methods such as nuclear magenetic resonance, pyrolysis/mass spectroscopy, and Fourier transform infrared spectroscopy. We generally have relied on proximate analysis for quantitative determination of several organic fractions (i.e., water-soluble carbohydrates, soluble nonpolars, water-soluble phenolics, holocellulose, and acid insoluble material). Our approaches to studying organic matter quality in relation to C turnover in peatlands include 1) 14C labelling of peatland vegetation along a latitudinal gradient in North America, allowing us to follow the fate of 14C tracer in belowground organic fractions under varying climates, 2) litter bag studies focusing on the role of individual moss species in litter quality and organic matter decomposition, and 3) laboratory incubations of peat to explore relationships between organic matter quality and decay. These studies suggest that proximate organic fractions vary in lability, but that turnover of organic matter is influenced both by plant species and climate. Across boreal peatlands, measures of soil recalcitrance such as acid

  4. Ecological Condition of Streams in Northern Nevada EPA R-MAP Humboldt Basin Project

    EPA Science Inventory

    This report presents stream data on the Humboldt River Basin in northern Nevada using the R-EMAP Program. Water is of primary importance to both the economy and the ecology of the region. Many of the waters of Nevada have previously received relatively little attention in regar...

  5. Late Cenozoic deep weathering patterns on the Fennoscandian shield in northern Finland: A window on ice sheet bed conditions at the onset of Northern Hemisphere glaciation

    NASA Astrophysics Data System (ADS)

    Hall, Adrian M.; Sarala, Pertti; Ebert, Karin

    2015-10-01

    The nature of the regolith that existed on the shields of the Northern Hemisphere at the onset of ice sheet glaciation is poorly constrained. In this paper, we provide the first detailed account of an exceptionally preserved, deeply weathered late Neogene landscape in the ice sheet divide zone in northern Finland. We mine data sets of drilling and pitting records gathered by the Geological Survey of Finland to reconstruct regional preglacial deep weathering patterns within a GIS framework. Using a large geochemical data set, we give standardised descriptions of saprolite geochemistry using a variant of the Weathering Index of Parker (WIP) as a proxy to assess the intensity of weathering. We also focus on mineral prospects and mines with dense pit and borehole data coverage in order to identify links between geology, topography, and weathering. Geology is closely linked to topography on the preglacial shield landscape of northern Finland and both factors influence weathering patterns. Upstanding, resistant granulite, granite, gabbro, metabasalt, and quartzite rocks were associated with fresh rock outcrops, including tors, or with thin (< 5 m) grusses. Plains developed across less resistant biotite gneisses, greenstones, and belts of alternating rock types were mainly weathered to thick (10-20 m) grusses with WIPfines values above 3000 and 4000. Beneath valley floors developed along mineralised shear and fracture zones, weathering penetrated locally to depths of > 50 m and included intensely weathered kaolinitic clays with WIPfines values below 1000. Late Neogene weathering profiles were varied in character. Tripartite clay-gruss-saprock profiles occur only in limited areas. Bipartite gruss-saprock profiles were widespread, with saprock thicknesses of > 10 m. Weathering profiles included two discontinuities in texture, materials and resistance to erosion, between saprolite and saprock and between saprock and rock. Limited core recovery when drilling below the soil

  6. The Influence of Fold and Fracture Development on Reservoir Behavior of the Lisburne Group of Northern Alaska

    SciTech Connect

    Wallace, Wesley K.; Hanks, Catherine L.; Whalen, Michael T.; Jensen1, Jerry; Shackleton, J. Ryan; Jadamec, Margarete A.; McGee, Michelle M.; Karpov1, Alexandre V.

    2001-07-23

    The Carboniferous Lisburne Group is a major carbonate reservoir unit in northern Alaska. The lisburne is detachment folded where it is exposed throughout the northeastern Brooks Range, but is relatively underformed in areas of current production in the subsurface of the North Slope. The objectives of this study are to develop a better understanding of four major aspects of the Lisburne: (1) The geometry and kinematics of detachment folds and their truncation by thrust faults, (2) The influence of folding on fracture patterns, (3) The influence of deformation on fluid flow, and (4) Lithostratigraphy and its influence on folding, faulting, fracturing, and reservoir characteristics.

  7. Estrous cycle phase and gonadal hormones influence conditioned fear extinction

    PubMed Central

    Milad, Mohammed R; Igoe, Sarah A; Lebron-Milad, Kelimer; Novales, Juan E

    2009-01-01

    Gonadal hormones modulate fear acquisition, but less is known about the influence of gonadal hormones on fear extinction. We assessed sex differences and the influence of gonadal hormone fluctuations and exogenous manipulations of estrogen and progesterone on acquisition, extinction learning and extinction recall in a 3-day auditory fear conditioning and extinction protocol. Experiments were conducted on males and naturally cycling female rats. Regarding female rats, significant differences in fear extinction were observed between subgroups of females, depending on their phase of the estrous cycle. Extinction that took place during the proestrus (high estrogen/progesterone) phase was more fully consolidated, as evidenced by low freezing during a recall test. This suggests that estrogen and/or progesterone facilitate extinction. In support of this, injection of both estrogen and progesterone prior to extinction learning in female rats during the metestrus phase of the cycle (low estrogen/progesterone) facilitated extinction consolidation, and blockade of estrogen and progesterone receptors during the proestrus phase impaired extinction consolidation. When comparing male to female rats without consideration of the estrous cycle phase, no significant sex differences were observed. When accounting for cycle phase in females, sex differences were observed only during extinction recall. Female rats that underwent extinction during the metestrus phase showed significantly higher freezing during the recall test relative to males. Collectively, these data suggest that gonadal hormones influence extinction behavior possibly by influencing the function of brain regions involved in the consolidation of fear extinction. Moreover, the elevated fear observed in female relative to male rats during extinction recall suggests that gonadal hormones may in part play a role in the higher prevalence of anxiety disorders in women. PMID:19761818

  8. Turbidity and salinity in a tropical northern Australian estuary and their influence on fish distribution

    NASA Astrophysics Data System (ADS)

    Cyrus, D. P.; Blaber, S. J. M.

    1992-12-01

    Turbidity and salinity and their influences on fish distribution were studied for two and a half years in the Embley Estuary in tropical northern Australia. Both turbidity and salinity varied significantly during the year but three clearly distinguishable seasonal patterns existed. These are referred to as the Wet, Early Dry and Late Dry Seasons. During each of these seasons distinct gradients of turbidity and salinity were present. The turbidity and salinity gradients were continuous with those in the adjacent marine environment of Albatross Bay. The levels and ranges of both factors were largely determined by the seasonal rainfall patterns in the catchment of the Embley River. The distribution and abundance of the 45 most common species was analysed in relation to turbidity, salinity and temperature patterns in the estuary. These data showed that fish densities within the estuary were related to turbidity and salinity but not temperature. There was a strong inverse relationship between turbidity and salinity. The Catch per Unit Effort (CPUE) of each species was determined in each of three broad ranges of turbidity and salinity. From this, patterns related to these two factors were found for 30 of the 45 species of fish.

  9. Marine foraging ecology influences mercury bioaccumulation in deep-diving northern elephant seals

    PubMed Central

    Peterson, Sarah H.; Ackerman, Joshua T.; Costa, Daniel P.

    2015-01-01

    Mercury contamination of oceans is prevalent worldwide and methylmercury concentrations in the mesopelagic zone (200–1000 m) are increasing more rapidly than in surface waters. Yet mercury bioaccumulation in mesopelagic predators has been understudied. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometres to forage within coastal and open-ocean regions of the northeast Pacific Ocean. We coupled satellite telemetry, diving behaviour and stable isotopes (carbon and nitrogen) from 77 adult females, and showed that variability among individuals in foraging location, diving depth and δ13C values were correlated with mercury concentrations in blood and muscle. We identified three clusters of foraging strategies, and these resulted in substantially different mercury concentrations: (i) deeper-diving and offshore-foraging seals had the greatest mercury concentrations, (ii) shallower-diving and offshore-foraging seals had intermediate levels, and (iii) coastal and more northerly foraging seals had the lowest mercury concentrations. Additionally, mercury concentrations were lower at the end of the seven-month-long foraging trip (n = 31) than after the two-month- long post-breeding trip (n = 46). Our results indicate that foraging behaviour influences mercury exposure and mesopelagic predators foraging in the northeast Pacific Ocean may be at high risk for mercury bioaccumulation. PMID:26085591

  10. Female hormone influences on sexual assaults in Northern Ireland from 2002 to 2009.

    PubMed

    Beirne, Patricia; Hall, Janet; Grills, Claire; Moore, Tara

    2011-10-01

    In Northern Ireland 1 in every 454 women of 13 years and over during 2008/09 reported to police that they had suffered a sexual assault. This study considered the possibility that women may be more likely to be victims of sexual assault during the fertile phase of their reproductive cycle. Evolutionary psychology suggests that women would have suffered more negative consequences if sexually assaulted when fertile and that specific psychological mechanisms may have evolved in women to combat male coercion. Female behaviours towards men vary across the reproductive cycle and men's behaviour towards women may vary also as a result of changes in female hormones. Hormones play a major role in producing the characteristic cyclical changes throughout a woman's reproductive life. This study is the first study of female hormone influences on sexual assaults. The data for the study was collated retrospectively from the records of 105 females with regular, spontaneous menstrual cycles. These females alleged recent sexual assault and were examined in Belfast during the period 2002-2009. The study concluded that young girls in the middle of their cycle, i.e. the fertile phase, were most at risk of sexual assault. It is possible that both sexes are sensitive to signs, albeit subtle behavioural signs, indicating high risk of conception. PMID:21907935

  11. Marine foraging ecology influences mercury bioaccumulation in deep-diving northern elephant seals.

    PubMed

    Peterson, Sarah H; Ackerman, Joshua T; Costa, Daniel P

    2015-07-01

    Mercury contamination of oceans is prevalent worldwide and methylmercury concentrations in the mesopelagic zone (200-1000 m) are increasing more rapidly than in surface waters. Yet mercury bioaccumulation in mesopelagic predators has been understudied. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometres to forage within coastal and open-ocean regions of the northeast Pacific Ocean. We coupled satellite telemetry, diving behaviour and stable isotopes (carbon and nitrogen) from 77 adult females, and showed that variability among individuals in foraging location, diving depth and δ(13)C values were correlated with mercury concentrations in blood and muscle. We identified three clusters of foraging strategies, and these resulted in substantially different mercury concentrations: (i) deeper-diving and offshore-foraging seals had the greatest mercury concentrations, (ii) shallower-diving and offshore-foraging seals had intermediate levels, and (iii) coastal and more northerly foraging seals had the lowest mercury concentrations. Additionally, mercury concentrations were lower at the end of the seven-month-long foraging trip (n = 31) than after the two-month- long post-breeding trip (n = 46). Our results indicate that foraging behaviour influences mercury exposure and mesopelagic predators foraging in the northeast Pacific Ocean may be at high risk for mercury bioaccumulation. PMID:26085591

  12. Marine foraging ecology influences mercury bioaccumulation in deep-diving northern elephant seals

    USGS Publications Warehouse

    Peterson, Sarah H.; Ackerman, Joshua T.; Costa, Daniel P.

    2015-01-01

    Mercury contamination of oceans is prevalent worldwide and methylmercury concentrations in the mesopelagic zone (200–1000 m) are increasing more rapidly than in surface waters. Yet mercury bioaccumulation in mesopelagic predators has been understudied. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometres to forage within coastal and open-ocean regions of the northeast Pacific Ocean. We coupled satellite telemetry, diving behaviour and stable isotopes (carbon and nitrogen) from 77 adult females, and showed that variability among individuals in foraging location, diving depth and δ13C values were correlated with mercury concentrations in blood and muscle. We identified three clusters of foraging strategies, and these resulted in substantially different mercury concentrations: (i) deeper-diving and offshore-foraging seals had the greatest mercury concentrations, (ii) shallower-diving and offshore-foraging seals had intermediate levels, and (iii) coastal and more northerly foraging seals had the lowest mercury concentrations. Additionally, mercury concentrations were lower at the end of the seven-month-long foraging trip (n = 31) than after the two-month- long post-breeding trip (n = 46). Our results indicate that foraging behaviour influences mercury exposure and mesopelagic predators foraging in the northeast Pacific Ocean may be at high risk for mercury bioaccumulation.

  13. Landscape Changes Influence the Occurrence of the Melioidosis Bacterium Burkholderia pseudomallei in Soil in Northern Australia

    PubMed Central

    Kaestli, Mirjam; Mayo, Mark; Harrington, Glenda; Ward, Linda; Watt, Felicity; Hill, Jason V.; Cheng, Allen C.; Currie, Bart J.

    2009-01-01

    Background The soil-dwelling saprophyte bacterium Burkholderia pseudomallei is the cause of melioidosis, a severe disease of humans and animals in southeast Asia and northern Australia. Despite the detection of B. pseudomallei in various soil and water samples from endemic areas, the environmental habitat of B. pseudomallei remains unclear. Methodology/Principal Findings We performed a large survey in the Darwin area in tropical Australia and screened 809 soil samples for the presence of these bacteria. B. pseudomallei were detected by using a recently developed and validated protocol involving soil DNA extraction and real-time PCR targeting the B. pseudomallei–specific Type III Secretion System TTS1 gene cluster. Statistical analyses such as multivariable cluster logistic regression and principal component analysis were performed to assess the association of B. pseudomallei with environmental factors. The combination of factors describing the habitat of B. pseudomallei differed between undisturbed sites and environmentally manipulated areas. At undisturbed sites, the occurrence of B. pseudomallei was found to be significantly associated with areas rich in grasses, whereas at environmentally disturbed sites, B. pseudomallei was associated with the presence of livestock animals, lower soil pH and different combinations of soil texture and colour. Conclusions/Significance This study contributes to the elucidation of environmental factors influencing the occurrence of B. pseudomallei and raises concerns that B. pseudomallei may spread due to changes in land use. PMID:19156200

  14. Hunting influences the diel patterns in habitat selection by northern pintails Anas acuta

    USGS Publications Warehouse

    Casazza, Michael L.; Coates, Peter S.; Miller, Michael R.; Overton, Cory T.; Yparraguirre, Daniel R.

    2012-01-01

    Northern pintail Anas acuta (hereafter pintail) populations wintering within Suisun Marsh, a large estuarine managed wetland near San Francisco Bay, California,USA, have declined markedly over the last four decades. The reasons for this decline are unclear. Information on how hunting and other factors influence the selection of vegetation types and sanctuaries would be beneficial to manage pintail populations in SuisunMarsh. During 1991-1993, we radio-marked and relocated female pintails (individuals: N = 203, relocations: N = 7,688) within Suisun Marsh to investigate habitat selection during the non-breeding months (winter). We calculated selection ratios for different vegetation types and for sanctuaries, and examined differences in those ratios between hunting season (i.e. hunting and non-hunting), age (hatchyear and after-hatch-year), and time of day (daylight or night hours). We found that diel patterns in selection were influenced by hunting disturbance. For example, prior to the hunting season and during daylight hours, pintails selected areas dominated by brass buttons Cotula coronopifolia, a potentially important food source, usually outside of sanctuary boundaries. However, during the hunting season, pintails did not select brass buttons during daylight hours, but instead highly selected permanent pools, mostly within sanctuaries. Also, during the hunting season, pintails showed strong selection for brass buttons at night. Sanctuaries provided more area of permanent water pools than within hunting areas and appeared to function as important refugia during daylight hours of the hunting season. Wildlife managers should encourage large protected permanent pools adjacent to hunted wetlands to increase pintail numbers within wetland environments and responsibly benefit hunting opportunities while improving pintail conservation.

  15. Earthworm species influence on carbon-mineral association in a sugar maple forest in northern Minnesota

    NASA Astrophysics Data System (ADS)

    Lyttle, A.; Yoo, K.; Aufdenkampe, A. K.; Hale, C. M.; Sebestyen, S. D.

    2011-12-01

    Non-native European earthworms are invading previously earthworm-free hardwood forests in the northern Great Lakes Region. Whereas earthworms' impacts on soil morphology and geochemical properties have been well documented in agricultural settings, the role of earthworms in biogeochemical cycles of undisturbed forests remains poorly understood. The forest soils that were recently invaded by exotic earthworms, therefore, provide a unique opportunity to understand how and how much earthworms contribute to biogeochemistry of non-agricultural environments. Increased degree and extent of soil mixing is one of the better known consequences of the earthworm invasion. Our hypothesis is that invasive earthworms positively affect carbon (C) stabilization by enhancing contacts between organic matter and minerals. We are studying C-mineral complexation along a well-established earthworm chronosequence in a sugar maple forest in northern Minnesota. We have observed changes in total earthworm biomass, A horizon C storage, and total specific surface area (SSA) of minerals as the invasion progresses. Because each earthworm species has different feeding and dwelling habits, biogeochemical imprints of the invasion reflect not only earthworms' biomass but also their species composition. All earthworm species show an increase in their biomass with greater time length since the invasion, though epigeic earthworms tend to be the pioneer species. As the total earthworm biomass increases, we find greater incorporation of organic C into the A horizon; the O horizon thickness decreases from 8 to 0 cm as the A horizon thickens from ~5 cm to ~12 cm. While leaf litter biomass is negatively correlated with total earthworm biomass, dramatic decreases in litter biomass are coupled with considerable increases in the biomass of epi-endogeic species. Despite the general decrease in C storage in the A horizon with greater degree of invasion, the storages fluctuate along the transect because

  16. Pressure-temperature conditions in granulite facies rocks of the northern Canadian Shield, Arctic Canada

    SciTech Connect

    Frisch, T.

    1985-01-01

    The northernmost part of the Churchill Structural Province of the Canadian Shield, underlying 60,000 km/sup 2/ of southeastern Ellesmere Island, Coburg Island and eastern Devon Island, consists of granulite facies metasedimentary, meta-igneous and plutonic intrusive rocks 2400 to 1900 m.y. old. Garnet+pyroxene+plagioclase of quartzofeldspathic gneisses from Ellesmere and Coburg islands indicate pressures, at 750/sup 0/C, ranging from greater than or equal to 6 to approx. 4kb; the lower pressures are derived largely, but not solely, from rim compositions. Similar rocks from Devon Island consistently indicate higher pressures of 6 to 7 kb. Garnet and plagioclase cores in sillimanite+cordierite-rich pelitic gneisses give pressures between 5 and 6.5 kb at 750/sup 0/C, the highest pressures being found in Devon Island rocks. Orthopyroxene+cordierite symplectites around garnet in magnesian metapelites indicate pressures under 4 kb at 650/sup 0/C. All cordierite is clearly of retrograde origin, having formed as a result of decompression during uplift, but even the highest pressures determined fall below the stability limit of cordierite in metapelites. Circumstantial evidence exists for the former stable coexistence of orthopyroxene+sillimanite, which would attest to pressures well in excess of 7 kb, but existing geobarometric equilibria have been strongly influenced by retrograde processes. Retrograde pressure-temperature conditions may well predominate in many granulite terranes but are not always recognized due to a scarcity of suitable mineral assemblages.

  17. Geoeffective and Climate-Influencing Solar and Interplanetary Conditions

    NASA Astrophysics Data System (ADS)

    Baranyi, T.; Ludmány, A.

    Several connections have been detected and demonstrated between solar magnetic conditions and climatic responses which hint at a highly complicated mechanism of sun-climate relations through plasma streams. The present contribution overviews our results about the possible factors of this mechanism. The main factor is the negative value of the interplanetary magnetic B_z component which exhibits a fairly complex behaviour. Its strength is influenced by the solar dipole cycle, the nature of ejected plasma (CME or fast stream), the magnetic topology of the CME and the position of the Earth (Rosenberg-Coleman and Russell-McPherron effects). The persistence of the negative B_z is also effective. The impacts of these features can be pointed out in the climatic responses.

  18. Influence of overconsolidated condition on permeability evolution in silica sand

    NASA Astrophysics Data System (ADS)

    Kimura, S.; Kaneko, H.; Ito, T.; Nishimura, O.; Minagawa, H.

    2013-12-01

    Permeability of sediments is important factors for production of natural gas from natural gas hydrate bearing layers. Methane-hydrate is regarded as one of the potential resources of natural gas. As results of coring and logging, the existence of a large amount of methane-hydrate is estimated in the Nankai Trough, offshore central Japan, where many folds and faults have been observed. In the present study, we investigate the permeability of silica sand specimen forming the artificial fault zone after large displacement shear in the ring-shear test under two different normal consolidated and overconsolidated conditions. The significant influence of overconsolidation ratio (OCR) on permeability evolution is not found. The permeability reduction is influenced a great deal by the magnitude of normal stress during large displacement shearing. The grain size distribution and structure observation in the shear zone of specimen after shearing at each normal stress level are analyzed by laser scattering type particle analyzer and scanning electron microscope, respectively. It is indicated that the grain size and porosity reduction due to the particle crushing are the factor of the permeability reduction. This study is financially supported by METI and Research Consortium for Methane Hydrate Resources in Japan (the MH21 Research Consortium).

  19. The influence of landscape position on lake chemical responses to drought in northern Wisconsin

    USGS Publications Warehouse

    Webster, K.E.; Kratz, T.K.; Bowser, C.J.; Magnuson, J.J.; Rose, W.J.

    1996-01-01

    Climatic shifts to drier conditions during drought alter the hydrologic pathways of water and solute flow to aquatic ecosystems. We examined differences in drought-induced trends in the semiconservative cations, Ca+Mg, in seven northern Wisconsin lakes. These spanned the range of hydrologic settings in the region, including hydraulically mounded, groundwater flowthrough, and groundwater-discharge lakes. Parallel increases in concentration across the seven lakes during drought were attributable to evapoconcentration. However, we observed divergent trends for mass, which better reflects altered solute flux by accounting for changes in lake volume. Ca+Mg mass increased in three groundwater-dominated lakes as precipitation inputs were low and groundwater discharging from longer flowpaths became proportionately more important. In contrast, decreases in Ca+Mg mass for two precipitation-dominated lakes reflected diminished inputs of solute-rich groundwater. Landscape position, defined by the spatial position of a lake within a hydrologic flow system, accounted for the divergence in chemical responses to drought.

  20. Influence of leaching conditions for ecotoxicological classification of ash.

    PubMed

    Stiernström, S; Enell, A; Wik, O; Hemström, K; Breitholtz, M

    2014-02-01

    The Waste Framework Directive (WFD; 2008/98/EC) states that classification of hazardous ecotoxicological properties of wastes (i.e. criteria H-14), should be based on the Community legislation on chemicals (i.e. CLP Regulation 1272/2008). However, harmonizing the waste and chemical classification may involve drastic changes related to choice of leaching tests as compared to e.g. the current European standard for ecotoxic characterization of waste (CEN 14735). The primary aim of the present study was therefore to evaluate the influence of leaching conditions, i.e. pH (inherent pH (∼10), and 7), liquid to solid (L/S) ratio (10 and 1000 L/kg) and particle size (<4 mm, <1 mm, and <0.125 mm), for subsequent chemical analysis and ecotoxicity testing in relation to classification of municipal waste incineration bottom ash. The hazard potential, based on either comparisons between element levels in leachate and literature toxicity data or ecotoxicity testing of the leachates, was overall significantly higher at low particle size (<0.125 mm) as compared to particle fractions <1mm and <4mm, at pH 10 as compared to pH 7, and at L/S 10 as compared to L/S 1000. These results show that the choice of leaching conditions is crucial for H-14 classification of ash and must be carefully considered in deciding on future guidance procedures in Europe. PMID:24280620

  1. Influence of Spanwise Boundary Conditions on Slat Noise Simulations

    NASA Technical Reports Server (NTRS)

    Lockard, David P.; Choudhari, Meelan M.; Buning, Pieter G.

    2015-01-01

    The slat noise from the 30P/30N high-lift system is being investigated through computational fluid dynamics simulations with the OVERFLOW code in conjunction with a Ffowcs Williams-Hawkings acoustics solver. In the present study, two different spanwise grids are being used to investigate the effect of the spanwise extent and periodicity on the near-field unsteady structures and radiated noise. The baseline grid with periodic boundary conditions has a short span equal to 1/9th of the stowed chord, whereas the other, longer span grid adds stretched grids on both sides of the core, baseline grid to allow inviscid surface boundary conditions at both ends. The results indicate that the near-field mean statistics obtained using the two grids are similar to each other, as are the directivity and spectral shapes of the radiated noise. However, periodicity forces all acoustic waves with less than one wavelength across the span to be two-dimensional, without any variation in the span. The spanwise coherence of the acoustic waves is what is needed to make estimates of the noise that would be radiated from realistic span lengths. Simulations with periodic conditions need spans of at least six slat chords to allow spanwise variation in the low-frequencies associated with the peak of broadband slat noise. Even then, the full influence of the periodicity is unclear, so employing grids with a fine, central region and highly stretched meshes that go to slip walls may be a more efficient means of capturing the spanwise decorrelation of low-frequency acoustic phenomena.

  2. Low impact of dry conditions on the CO2 exchange of a Northern-Norwegian blanket bog

    NASA Astrophysics Data System (ADS)

    Lund, Magnus; Bjerke, J. W.; Drake, B. G.; Engelsen, O.; Hansen, G. H.; Parmentier, F. J. W.; Powell, T. L.; Silvennoinen, H.; Sottocornola, M.; Tømmervik, H.; Weldon, S.; Rasse, D. P.

    2015-02-01

    Northern peatlands hold large amounts of organic carbon (C) in their soils and are as such important in a climate change context. Blanket bogs, i.e. nutrient-poor peatlands restricted to maritime climates, may be extra vulnerable to global warming since they require a positive water balance to sustain their moss dominated vegetation and C sink functioning. This study presents a 4.5 year record of land-atmosphere carbon dioxide (CO2) exchange from the Andøya blanket bog in northern Norway. Compared with other peatlands, the Andøya peatland exhibited low flux rates, related to the low productivity of the dominating moss and lichen communities and the maritime settings that attenuated seasonal temperature variations. It was observed that under periods of high vapour pressure deficit, net ecosystem exchange was reduced, which was mainly caused by a decrease in gross primary production. However, no persistent effects of dry conditions on the CO2 exchange dynamics were observed, indicating that under present conditions and within the range of observed meteorological conditions the Andøya blanket bog retained its C uptake function. Continued monitoring of these ecosystem types is essential in order to detect possible effects of a changing climate.

  3. FACTORS INFLUENCING DISCRIMINATION BETWEEN INSECTICIDE-TREATED AND UNTREATED FOODS BY NORTHERN BOBWHITE

    EPA Science Inventory

    Tests were conducted to determine at what dietary concentrations northern bobwhite (Colinus virginianus) chicks (14 days old) could discriminate between pesticide-treated and untreated food using an organophosphate (OP) insecticide, parathion, and two carbamates, carbofuran and m...

  4. Historical Influences on Contemporary Tobacco Use by Northern Plains and Southwestern American Indians.

    PubMed

    Kunitz, Stephen J

    2016-02-01

    There are great differences in smoking- and tobacco-related mortality between American Indians on the Northern Plains and those in the Southwest that are best explained by (1) ecological differences between the two regions, including the relative inaccessibility and aridity of the Southwest and the lack of buffalo, and (2) differences between French and Spanish Indian relations policies. The consequence was the disruption of inter- and intratribal relations on the Northern Plains, where as a response to disruption the calumet (pipe) ceremony became widespread, whereas it did not in the Southwest. Tobacco was, thus, integrated into social relationships with religious sanctions on the Northern Plains, which increased the acceptability of commercial cigarettes in the 20th century. Smoking is, therefore, more deeply embedded in religious practices and social relationships on the Northern Plains than in the Southwest. PMID:26691134

  5. Historical Influences on Contemporary Tobacco Use by Northern Plains and Southwestern American Indians

    PubMed Central

    2016-01-01

    There are great differences in smoking- and tobacco-related mortality between American Indians on the Northern Plains and those in the Southwest that are best explained by (1) ecological differences between the two regions, including the relative inaccessibility and aridity of the Southwest and the lack of buffalo, and (2) differences between French and Spanish Indian relations policies. The consequence was the disruption of inter- and intratribal relations on the Northern Plains, where as a response to disruption the calumet (pipe) ceremony became widespread, whereas it did not in the Southwest. Tobacco was, thus, integrated into social relationships with religious sanctions on the Northern Plains, which increased the acceptability of commercial cigarettes in the 20th century. Smoking is, therefore, more deeply embedded in religious practices and social relationships on the Northern Plains than in the Southwest. PMID:26691134

  6. Physical Conditions Associated with Widespread Seafloor Methane Discharge on the Northern US Atlantic Margin

    NASA Astrophysics Data System (ADS)

    Skarke, A. D.; Ruppel, C. D.; Brothers, D. S.

    2014-12-01

    Recent analysis of water column backscatter data and remotely operated vehicle (ROV) video imagery collected by NOAA Ship Okeanos Explorer between 2011 and 2013 revealed methane discharge from the seafloor at over 570 gas seep locations along the northern US Atlantic margin. To the best of our knowledge, such large-scale seepage has not previously been observed on a passive margin outside the Arctic or not spatially associated with a petroleum basin. This seepage has implications for the global carbon cycle, ocean chemistry (e.g., acidification), and in some cases, the climate system. Using data collected by Okeanos Explorer and NOAA's Deep Discoverer ROV, we combine water column backscatter data with video imagery and seafloor backscatter data to estimate gas flux and constrain the geoacoustic properties of the seabed at methane discharge sites. The total methane flux from the northern US Atlantic margin seeps is conservatively estimated at ~15-90 Mg y-1, based on observations of gas bubble volume, discharge rates, and discharge points per site. However, fewer than 1% of the identified seep sites have been inspected with a ROV, and this estimate is likely to be revised upward as the characteristics of the seeps are further constrained. Another important observation to emerge from our analysis is the lack of spatial correlation between seep sites and the ~5000 pockmarks mapped on the northern part of the US Atlantic margin. In this region, pockmarks, which are often easily identified by geophysical imaging of the seafloor, should not be considered potential target sites for finding undiscovered areas of seepage. Conversely, discrete patches of elevated relative seafloor acoustic backscatter amplitude do appear to be correlated with the spatial distribution of methane seeps, implying anomalous seafloor characteristic at seep loci. This finding is consistent with ROV video observations of authigenic carbonate outcrops and extensive chemosynthetic bivalve communities

  7. The influence of scaffold material on chondrocytes in inflammatory conditions

    PubMed Central

    Kwon, Heenam; Sun, Lin; Cairns, Dana M.; Rainbow, Roshni S.; Preda, Rucsanda Carmen; Kaplan, David L.; Zeng, Li

    2013-01-01

    Cartilage tissue engineering aims to repair damaged cartilage tissue in arthritic joints. As arthritic joints have significantly higher levels of pro-inflammatory cytokines (such as IL-1β and TNFα that cause cartilage destruction, it is critical to engineer stable cartilage in an inflammatory environment. Biomaterial scaffolds constitute an important component of the microenvironment for chondrocytes in engineered cartilage. However, it remains unclear how scaffold material influences the response of chondrocytes seeded in these scaffolds under inflammatory stimuli. Here, we compared the response of articular chondrocytes seeded within three different polymeric scaffolding materials (silk, collagen and polylactic acid (PLA)) to IL-1β and TNFα. These scaffolds have different physical characteristics and yielded significant differences in the expression of genes associated with cartilage matrix production and degradation, cell adhesion and cell death. Silk and collagen scaffolds released pro-inflammatory cytokines faster and had higher uptake water abilities than PLA scaffolds. Correspondingly, chondrocytes cultured in silk and collagen scaffolds maintained higher levels of cartilage matrix than those in PLA, suggesting that these biophysical properties of scaffolds may regulate gene expression and response to inflammatory stimuli in chondrocytes. Based on this study, we concluded that selecting the proper scaffolding material will aid in the engineering of more stable cartilage tissues for cartilage repair; and that silk and collagen are the more optimal scaffolds in supporting the stability of 3D cartilage under inflammatory conditions. PMID:23333441

  8. On the influence of mechanical conditions in osteochondral defect healing.

    PubMed

    Duda, Georg N; Maldonado, Zully M; Klein, Petra; Heller, Markus O W; Burns, Justin; Bail, Hermann

    2005-04-01

    Despite the introduction of new surgical techniques, the treatment of cartilage defects remains challenging. Delay or complete failure of cartilage healing is associated with problems in biological regeneration. The influence of mechanical conditions on this process, however, remains unevaluated. Osteochondral defects were generated on the left femoral condyle in 18 Yucatan minipigs. After 4, 6 and 12 weeks the defect filling, trabecular orientation and bone density were compared to the intact contralateral side. The mechanical straining during this period was then analyzed using an adaptive finite element technique. Histologically, the osteochondral defects showed bone resorption at the base and bone formation from the circumference. At 12 weeks, the macroscopically healed specimens showed fibrous cartilage formation, a minimally organized trabecular structure and increased trabecular volume fraction compared to the controls (p < 0.002). The amount of cancellous, cartilagineous, and fibrous tissue and the defect size as measured in histomorphometric analysis for the three time points (4, 6 and 12 weeks) was comparable in magnitude to that predicted by finite element analysis. The simulated osteochondral healing process was not fully capable of re-establishing a hyaline-like cartilage layer. The correlation between simulation and histology allows identification of mechanical factors that appear to have a larger impact on the healing of osteochondral defects than previously considered. PMID:15713306

  9. Influence of a flood event on salinity and nutrients in the Changshan Archipelago area (Northern Yellow Sea)

    NASA Astrophysics Data System (ADS)

    Zhang, Guangtao; Zhao, Zengxia; Liu, Changhua; Liu, Qun; Ren, Jianming

    2012-09-01

    River discharge can deliver nutrients to the coastal zone and change the hydrologic properties of the water column. Soon after a flash flood from the Yalu River (Northeast China) in August 2010, we investigated the salinity and nutrient concentrations, as well as other environmental conditions in the Changshan Archipelago area, located approximately 100 km west of the river mouth in the northern Yellow Sea. Diluted water was mainly observed in the upper layers shallower than 15 m, with surface salinity between 18.13 and 30.44 in the eastern study area and between 28.16 and 29.72 in the western area. Surface salinity showed a significant negative correlation with concentrations of dissolved nutrients ( P < 0.05), but not with that of Chlorophyll- a (Chl- a), dissolved oxygen (DO), particulate materials or pH. The average concentrations of nitrite, nitrate, and silicic acid decreased from the surface layer to bottom layer and were significantly higher in the east area than in the west area ( P < 0.05). In contrast, average ammonium and phosphate concentrations were highest in the bottom layer of both areas, with no significant spatial differences. DO varied between 6.06 and 8.25 mg L-1 in the surface layer, and was significantly higher in the eastern area than in the western area in the surface and middle layers. Chl- a concentration was constantly below 4.09 μg L-1. Our work demonstrated the strong influences of Yalu River on proportions of various nutrient components in the Changshan Archipelago area. Silicic acid and total inorganic nitrogen levels were significantly elevated comparing to phosphate in the eastern area. Such changes can potentially induce phosphate limit to phytoplankton growth.

  10. Evaluation of sampling strategies to characterize dissolved oxygen conditions in northern Gulf of Mexico estuaries

    SciTech Connect

    Summers, J.K.; Engle, V.D.

    1993-01-01

    Dissolved oxygen was continuously monitored in eight sites of northern Gulf of Mexico estuaries in August, 1990. Monte Carlo analyses on subsamples of the data were used to evaluate several commonly used monitoring strategies. Monitoring strategies which involve single point sampling of dissolved oxygen may often misclassify an estuary as having good water quality. In the case of shallow, often well-mixed estuaries that experience diurnal cycles, such monitoring often does not occur at night, during the time of lowest dissolved oxygen concentration. The authors' objective was to determine the minimum sampling effort required to correctly classify a site in terms of the observed frequency of hypoxia. Tests concluded that the most successful classification strategy used the minimum dissolved oxygen concentration from a continuously sampled 24-hour period. (Copyright (c) 199e Kluwer Academic Publishers.)

  11. Habitat manipulation influences northern bobwhite resource selection on a reclaimed surface mine

    USGS Publications Warehouse

    Brooke, Jarred M.; Peters, David C.; Unger, Ashley M.; Tanner, Evan P.; Harper, Craig A.; Keyser, Patrick D.; Clark, Joseph D.; Morgan, John J.

    2015-01-01

    More than 600,000 ha of mine land have been reclaimed in the eastern United States, providing large contiguous tracts of early successional vegetation that can be managed for northern bobwhite (Colinus virginianus). However, habitat quality on reclaimed mine land can be limited by extensive coverage of non-native invasive species, which are commonly planted during reclamation. We used discrete-choice analysis to investigate bobwhite resource selection throughout the year on Peabody Wildlife Management Area, a 3,330-ha reclaimed surface mine in western Kentucky. We used a treatment-control design to study resource selection at 2 spatial scales to identify important aspects of mine land vegetation and whether resource selection differed between areas with habitat management (i.e., burning, disking, herbicide; treatment) and unmanaged units (control). Our objectives were to estimate bobwhite resource selection on reclaimed mine land and to estimate the influence of habitat management practices on resource selection. We used locations from 283 individuals during the breeding season (1 Apr–30 Sep) and 136 coveys during the non-breeding season (1 Oct–Mar 31) from August 2009 to March 2014. Individuals were located closer to shrub cover than would be expected at random throughout the year. During the breeding season, individuals on treatment units used areas with smaller contagion index values (i.e., greater interspersion) compared with individuals on control units. During the non-breeding season, birds selected areas with greater shrub-open edge density compared with random. At the microhabitat scale, individuals selected areas with increased visual obstruction >1 m aboveground. During the breeding season, birds were closer to disked areas (linear and non-linear) than would be expected at random. Individuals selected non-linear disked areas during winter but did not select linear disked areas (firebreaks) because they were planted to winter wheat each fall and

  12. The Influence of European Pollution on Ozone in the Near East and Northern Africa

    NASA Technical Reports Server (NTRS)

    Duncan, B. N.; West, J. J.; Yoshida, Y.; Fiore, A. M.; Ziemke, J. R.

    2008-01-01

    We present a modeling study of the long-range transport of pollution from Europe, showing that European emissions regularly elevate surface ozone by as much as 20 ppbv in summer in northern Africa and the Near East. European emissions cause 50-150 additional violations per year (i.e. above those that would occur without European pollution) of the European health standard for ozone (8-h average greater than 120 micrograms per cubic meters or approximately 60 ppbv) in northern Africa and the Near East. We estimate that European ozone pollution is responsible for 50 000 premature mortalities globally each year, of which the majority occurs outside of Europe itself, including 37% (19 000) in northern Africa and the Near East. Much of the pollution from Europe is exported southward at low altitudes in summer to the Mediterranean Sea, northern Africa and the Near East, regions with favorable photochemical environments for ozone production. Our results suggest that assessments of the human health benefits of reducing ozone precursor emissions in Europe should include effects outside of Europe, and that comprehensive planning to improve air quality in northern Africa and the Near East likely needs to address European emissions.

  13. Influence of combined oral contraceptives on the periodontal condition

    PubMed Central

    DOMINGUES, Roberta Santos; FERRAZ, Bruna Fidêncio Rahal; GREGHI, Sebastião Luiz Aguiar; de REZENDE, Maria Lúcia Rubo; PASSANEZI, Euloir; SANT'ANA, Adriana Campos Passanezi

    2012-01-01

    Most studies investigating the impact of oral contraceptives have been performed some years ago, when the level of sexual hormones was greater than the actual formulations. Objective The aim of this study was to evaluate the effects of current combined oral contraceptives (COC) on periodontal tissues, correlating the clinical parameters examined with the total duration of continuous oral contraceptive intake. Material and methods Twenty-five women (19-35 years old) taking combined oral contraceptives for at least 1 year were included in the test group. The control group was composed by 25 patients at the same age range reporting no use of hormone-based contraceptive methods. Clinical parameters investigated included pocket probing depth (PD), clinical attachment level (CAL), sulcular bleeding index (SBI) and plaque index (Pl.I). Data were statistically evaluated by unpaired t test, Pearson's correlation test and Spearman's correlation test. Results The test group showed increased PD (2.228±0.011 x 2.154±0.012; p<0.0001) and SBI (0.229±0.006 x 0.148±0.005, p<0.0001) than controls. No significant differences between groups were found in CAL (0.435±0.01 x 0.412±0.01; p=0.11). The control group showed greater Pl.I than the test group (0.206±0.007 x 0.303±0.008; p<0.0001). No correlation between the duration of oral contraceptive intake, age and periodontal parameters was observed. Conclusions These findings suggest that the use of currently available combined oral contraceptives can influence the periodontal conditions of the patients, independently of the level of plaque accumulation or total duration of medication intake, resulting in increased gingival inflammation. PMID:22666846

  14. The Influence of Global Climate Changes on Storm-Tracks of Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Martynova, Y.; Krupchatnikov, V. N.

    2012-12-01

    Non-stationary eddies in mid-latitude storm-tracks are an important mechanism of energy, moment and moisture transfer in climate system [1]. Baroclinic eddies bring heavy rains and other hazard weather phenomena in the middle latitudes, play an important role in the global energy and the hydrological cycle. Recently, the increase of a cyclones rate at high latitudes with their frequency decrease in the second half of the 20th century was discovered using reanalysis data [2,3]. However, there is still no common point of view about how storm-track's distribution and intensity will be changed under the climate change influence [4,5]. In our work we investigate a variation of transient eddies general propagation tracks as a result of the global climate change effect. Using global large-scale intermediate complexity model of climate system [6] the numerical experiment was provided for the time period from 850 to 3000 year with a scenario of greenhouse gases influence on climate. From 850 to 2005 this impact was set according to the protocol "Historical simulations" of CMIP5 [7]. For 21th century anthropogenic effects were set according to the most aggressive scenario RCP 8.5 [8]. For the period 22-23 centuries CO2 concentration was on the level of 2100 year, and for 24-30 centuries it returned to pre-industrial value linearly in time of 100 years. Using a filter [9] we defined three variation intervals: low-frequency, medium-frequency and high-frequency. In our work we paid attention to medium-scale waves (i.e. 2-8 days). Two seasons were chosen: winter and summer. For each season we considered average fields of parameters characterizing poleward heat flux at 700 mb and transient eddies variance at 250 mb. Besides of the sensitivity of storm-track dynamic we considered some other features of "warm" climate. The work is partially supported by The Ministry of Education and Science of the Russian Federation #(#07.514.11.4044), RFBR grants #10-07-00547, #11-05-01190, and SB

  15. Fluvial depositional environment evolving into deltaic setting with marine influences in the buntsandstein of northern vosges (France)

    NASA Astrophysics Data System (ADS)

    Gall, Jean-Claude

    The Buntsandstein in the Northern Vosges (France) originates mainly in an inland braidplain fluvial environment which passes in the upper part of the sequence into deltaic milieu in the coastal plain along the border of the sea, with the continental environment finally being drowned with the transgression of the shallow sea. The fluvial sedimentation is characterized by the presence of two facies throughout the Buntsandstein : channel facies and overbank plain facies. The channel facies comprises sandy and conglomeratic deposits forming within active streams by strong currents, whereas the overbank plain facies is built up of silty-clayey sandstones or silt/clay originating in stagnant water in abandoned watercourses, ponds, pools and puddles. The significance of particularly the floodplain sediments is subjected to considerable changes throughout the Buntsandstein sequence. There are all stages of transition between overbank plain deposits being only preserved in ghost-like facies as reworked clasts due to effective secondary removal of primarily occasionally formed suspension fines, and an abundance of autochthonous floodplain sediments in the depositional record resulting from favourable conditions of primary origin and secondary preservation. Reworked ventifacts within fluvial channel sediments testify to subordinate aeolian influences in the alluvial plain, with reasonable reworking, however, having removed all in situ traces of wind activity. Declining aridity of palaeoclimate towards the top is indicated by the appearance of violet horizon palaeosols in the Zone-Limite-Violette and the Couches intermédiaires being accompanied by Bröckelbank carbonate breccias originating from concentration of reworked fragments of pedogenic carbonate nodules. Biogenic traces are in the lower part of the sequence mainly present as Planolites burrows in the finer-grained sediments. Palaeosalinities as revealed from boron contents indicate progressively increasing

  16. The Influence of Specific Physical Health Conditions on Retirement Decisions

    ERIC Educational Resources Information Center

    Shultz, Kenneth S.; Wang, Mo

    2007-01-01

    Physical health has consistently been shown to strongly influence the retirement decision-making process. Unfortunately, "physical health" is typically operationalized in global terms. As a result, we know little about the specific aspects of physical health that influence the decision to retire. Therefore, in the present study, data from three…

  17. Crop Diversification and Management System Influence Yield and Weeds in the Northern Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Available water, depleted soil quality, and weed competition are major constraints to dryland crop production in the northern Great Plains. We initiated a trial in 2004 comparing four crop rotations, with each rotational component in a two-by-two matrix of tillage (conventional vs. zero tillage) an...

  18. Culture and Caregivers: Factors Influencing Breastfeeding among Mothers in West Belfast, Northern Ireland

    ERIC Educational Resources Information Center

    Bishop, Hilary; Cousins, Wendy; Casson, Karen; Moore, Ann

    2008-01-01

    Breastfeeding is a key public health measure to protect and promote the health of one of the most vulnerable groups of the population--infants and children. Northern Ireland, however, has one of the lowest breastfeeding rates in the world. This paper reports the results of a questionnaire survey of 120 mothers attending mother and toddler groups…

  19. Estimating soybean genetic gain for yield in the northern United States – Influence of cropping history

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mean on-farm USA soybean yield increased at a rate of 21.3 kg per ha per year between 1924 and 2010, due to adoption of yield-enhancing genetic and agronomic technologies. To estimate annual rates of genetic yield gain in three northern USA soybean maturity groups (MG) and determine if these estimat...

  20. The Influence of Meteorological Conditions on Air Pollution

    ERIC Educational Resources Information Center

    Campbell, N. A.; Gipps, J.

    1975-01-01

    Explains the distribution of air pollutants as related to such meteorological conditions as temperature inversions, ground inversion, and wind velocity. Uses a power station to illustrate the effect of some of the meteorological conditions mentioned. (GS)

  1. Is long range transport of pollen in the NW Mediterranean basin influenced by Northern Hemisphere teleconnection patterns?

    PubMed

    Izquierdo, Rebeca; Alarcon, Marta; Periago, Cristina; Belmonte, Jordina

    2015-11-01

    Climatic oscillations triggered by the atmospheric modes of the Northern Hemisphere teleconnection patterns have an important influence on the atmospheric circulation at synoptic scale in Western Mediterranean Basin. Simultaneously, this climate variability could affect a variety of ecological processes. This work provides a first assessment of the effect of North Atlantic Oscillation (NAO), Arctic Oscillation (AO) and Western Mediterranean Oscillation (WeMO) on the atmospheric long-range pollen transport episodes in the North-Eastern Iberian Peninsula for the period 1994-2011. Alnus, Ambrosia, Betula, Corylus and Fagus have been selected as allergenic pollen taxa with potential long-range transport associated to the Northern Hemisphere teleconnection patterns in the Western Mediterranean Basin. The results showed an increase of long range pollen transport episodes of: (1) Alnus, Corylus and Fagus from Western and Central Europe during the negative phase of annual NAO and AO; (2) Ambrosia, Betula and Fagus from Europe during the negative phase of winter WeMO; (3) Corylus and Fagus from Mediterranean area during the positive phase of the annual AO; and (4) Ambrosia from France and Northern Europe during the positive phase of winter WeMO. Conversely, the positive phase of annual NAO and AO are linked with the regional transport of Alnus, Betula and Corylus from Western Iberian Peninsula. The positive phase of annual WeMO was also positively correlated with regional transport of Corylus from this area. PMID:26125408

  2. Eight Conditions Influencing the Implementation of Educational Rights.

    ERIC Educational Resources Information Center

    Thomas, R. Murray

    The extent to which claims to educational rights are actually fulfilled in a society depends on a variety of conditions. There are eight conditions that can contribute to a society's falling short in the implementation of those rights. The conditions include: (1) complacency--failure to take steps toward ensuring that the right is honored in…

  3. Genetics Home Reference: Northern epilepsy

    MedlinePlus

    ... Understand Genetics Home Health Conditions Northern epilepsy Northern epilepsy Enable Javascript to view the expand/collapse boxes. Download PDF Open All Close All Description Northern epilepsy is a genetic condition that causes recurrent seizures ( ...

  4. Benthic conditions around a historic shipwreck: Vrouw Maria (1771) in the northern Baltic proper

    NASA Astrophysics Data System (ADS)

    Ruuskanen, A. T.; Kraufvelin, P.; Alvik, R.; Díaz, E. R.; Honkonen, J.; Kanerva, J.; Karell, K.; Kekäläinen, P.; Lappalainen, J.; Mikkola, R.; Mustasaari, T.; Nappu, N.; Nieminen, A.; Roininen, J.; Svahnbäck, K.

    2015-04-01

    Since her shipwreck in 1771, the wooden vessel Vrouw Maria has been lying on the seabed at 41 m depth on the border between the Archipelago Sea and the northern Baltic proper, off the southern coast of Finland. The wreck lies in an upward position in a right angle to the dominating bottom current, which is potentially affecting seabed topography, sediment characteristics and zoobenthic communities both upstream (NE) and downstream (SW) of the wreck. This multidisciplinary study attempts to clarify abiotic and biotic patterns and processes in the vicinity of the wreck by combining field investigations with physical simulation studies in the field and in the laboratory. Multibeam echo-sounder techniques were utilised to generate a map of the wreck area and sediment grab samples were taken to characterize the sediment type and its zoobenthic community. A medium-sized field experiment generated data on the accumulation of sediment organic matter in the presence and absence of a current and/or a barrier on the seafloor and a small-scaled laboratory study was conducted to simulate scour forming processes. The results showed that a deeper basin, scour area, with the dimensions 150×300 m, was present downstream of the wreck and there was also a smaller scour area upstream of the wreck. Similar traces on the bottom were simulated in the laboratory. The organic content (recent mud) and the proportion of finer sediment were more pronounced in areas closer to both sides of the wreck. These results were in turn imitated in a field experiment, where the accumulation of organic matter in the sediment increased significantly downstream, when a current was interrupted by a barrier. Regarding zoobenthos in the wreck area, 11 taxa and a mean total abundance of 773 individuals per m2 were registered. The dominant species were Macoma balthica and Marenzelleria sp., which together made up >80% of the total number of individuals. Multivariate data analyses showed significant differences

  5. Environmental Conditions in Northern Gulf of Mexico Estuaries: Before and After the Deepwater Horizon Oil Spill

    EPA Science Inventory

    When conducting an environmental assessment to determine the ecological effects of the Deepwater Horizon (DWH) Oil Spill in the Gulf of Mexico (GOM), baseline environmental data is essential to establish ecosystem condition prior to the incident. EPA’s National Coastal Assessment...

  6. Summer Fish Communities in Northern Gulf of Mexico Estuaries: Indices of Ecological Condition

    EPA Science Inventory

    We used fish community data from trawl samples in >100 estuaries, bayous, and coastal lagoons of the Louisianan Biogeographic Province (Gulf of Mexico) to develop indicators of ecological condition. One data set, from which we derived reference values for fish community indicator...

  7. Effects of Socioeconomic Status on Television Viewing Conditions of Preschoolers in Northern Greece

    ERIC Educational Resources Information Center

    Natsiopoulou, Triantafillia; Melissa-Halikiopoulou, Chrisoula

    2009-01-01

    The purpose of this study was to identify the effects of television (TV) on preschoolers, their TV viewing patterns and the conditions under which they watch TV, taking into consideration their different socioeconomic and regional backgrounds. The survey instrument was a questionnaire with 23 closed-ended questions, given to parents whose children…

  8. Chronic Heat Stress and Cognitive Development: An Example of Thermal Conditions Influencing Human Development

    ERIC Educational Resources Information Center

    Riniolo, Todd C.; Schmidt, Louis A.

    2006-01-01

    Although thermal conditions influence the development of living organisms in a wide variety of ways, this topic has been recently ignored in humans. This paper reintroduces thermal conditions as a topic of importance for developmentalists by presenting an example of how thermal conditions are hypothesized to influence a particular developmental…

  9. West Nile Virus Surveillance in 2013 via Mosquito Screening in Northern Italy and the Influence of Weather on Virus Circulation

    PubMed Central

    Calzolari, Mattia; Pautasso, Alessandra; Montarsi, Fabrizio; Albieri, Alessandro; Bellini, Romeo; Bonilauri, Paolo; Defilippo, Francesco; Lelli, Davide; Moreno, Ana; Chiari, Mario; Tamba, Marco; Zanoni, Mariagrazia; Varisco, Giorgio; Bertolini, Silvia; Modesto, Paola; Radaelli, Maria Cristina; Iulini, Barbara; Prearo, Marino; Ravagnan, Silvia; Cazzin, Stefania; Mulatti, Paolo; Monne, Isabella; Bonfanti, Lebana; Marangon, Stefano; Goffredo, Maria; Savini, Giovanni; Martini, Simone; Mosca, Andrea; Farioli, Marco; Gemma Brenzoni, Laura; Palei, Manlio; Russo, Francesca; Natalini, Silvano; Angelini, Paola; Casalone, Cristina; Dottori, Michele; Capelli, Gioia

    2015-01-01

    West Nile virus (WNV) is a recently re-emerged health problem in Europe. In Italy, an increasing number of outbreaks of West Nile disease, with occurrences of human cases, have been reported since 2008. This is particularly true in northern Italy, where entomological surveillance systems have been implemented at a regional level. The aim of this study was to use, for the first time, all the entomological data collected in the five regions undergoing surveillance for WNV in northern Italy to characterize the viral circulation (at a spatial and temporal scale), identify potential mosquito vectors, and specify relationships between virus circulation and meteorological conditions. In 2013, 286 sites covering the entire Pianura Padana area were monitored. A total of 757,461 mosquitoes were sampled. Of these, 562,079 were tested by real-time PCR in 9,268 pools, of which 180 (1.9%) were positive for WNV. The largest part of the detected WNV sequences belonged to lineage II, demonstrating that, unlike those in the past, the 2013 outbreak was mainly sustained by this WNV lineage. This surveillance also detected the Usutu virus, a WNV-related flavivirus, in 241 (2.6%) pools. The WNV surveillance systems precisely identified the area affected by the virus and detected the viral circulation approximately two weeks before the occurrence of onset of human cases. Ninety percent of the sampled mosquitoes were Culex pipiens, and 178/180 WNV-positive pools were composed of only this species, suggesting this mosquito is the main WNV vector in northern Italy. A significantly higher abundance of the vector was recorded in the WNV circulation area, which was characterized by warmer and less rainy conditions and greater evapotranspiration compared to the rest of the Pianura Padana, suggesting that areas exposed to these conditions are more suitable for WNV circulation. This observation highlights warmer and less rainy conditions as factors able to enhance WNV circulation and cause virus

  10. Influence of variations in extratropical wintertime teleconnections on Northern Hemisphere temperature

    SciTech Connect

    Hurrell, J.W.

    1997-11-01

    The purpose of this paper to illustrate and quantify the relationship between the circulation changes and surface temperature anomalies in the northern hemisphere during winter. Multivariate linear regression was used to regress three indices on the northern hemisphere extratropical temperature anomolies for each winter since 1935. The indices regressed were the North Atlantic Oscillation, the North Pacific, and the Southern Oscillation; these were selected because they relate to well understood circulation anomolies that have persisted for much of the past two decades. Elements of the temperature anomaly pattern since the mid-1970s resemble the greenhouse warming fingerprint predicted by some general circulation models; however, it is difficult to assess the cause. The changes in circulation since the mid-1970s have resulted in a particular surface temperature anomaly pattern that has amplified the hemispheric-averaged warming because of the interaction with land and ocean. 7 refs., 3 figs.

  11. Influences on maternal and child nutrition in the highlands of the northern Lao PDR.

    PubMed

    Holmes, Wendy; Hoy, Damian; Lockley, Anne; Thammavongxay, Khampho; Bounnaphol, Somphao; Xeuatvongsa, Anonh; Toole, Michael

    2007-01-01

    In two remote northern provinces of the Lao People's Democratic Republic, provincial and district teams were trained and subsequently conducted a qualitative study using a participatory approach to investigate people's knowledge, attitudes, beliefs and practices in relation to women's and children's nutrition. Using focus group discussions, key informant interviews, and structured observation, the teams found that certain nutrition behaviours, including food taboos, may contribute to the high prevalence of child malnutrition and micronutrient deficiencies in these northern provinces. Ethnic groups gave details of nutrition-related beliefs and practices; the teams found that many of these are likely to be amenable to change through relatively low-cost nutrition promotion informed by these findings. In particular, barriers to exclusive breastfeeding, food taboos and hygiene behaviour could be addressed. The study also demonstrated that with appropriate training, supervision and support, local teams are able to plan and conduct a large-scale qualitative study. PMID:17704036

  12. Suboptimal Light Conditions Influence Source-Sink Metabolism during Flowering

    PubMed Central

    Christiaens, Annelies; De Keyser, Ellen; Pauwels, Els; De Riek, Jan; Gobin, Bruno; Van Labeke, Marie-Christine

    2016-01-01

    Reliance on carbohydrates during flower forcing was investigated in one early and one late flowering cultivar of azalea (Rhododendron simsii hybrids). Carbohydrate accumulation, invertase activity, and expression of a purported sucrose synthase gene (RsSUS) was monitored during flower forcing under suboptimal (natural) and optimal (supplemental light) light conditions, after a cold treatment (7°C + dark) to break flower bud dormancy. Post-production sucrose metabolism and flowering quality was also assessed. Glucose and fructose concentrations and invertase activity increased in petals during flowering, while sucrose decreased. In suboptimal light conditions RsSUS expression in leaves increased as compared to optimal light conditions, indicating that plants in suboptimal light conditions have a strong demand for carbohydrates. However, carbohydrates in leaves were markedly lower in suboptimal light conditions compared to optimal light conditions. This resulted in poor flowering of plants in suboptimal light conditions. Post-production flowering relied on the stored leaf carbon, which could be accumulated under optimal light conditions in the greenhouse. These results show that flower opening in azalea relies on carbohydrates imported from leaves and is source-limiting under suboptimal light conditions. PMID:26973689

  13. Suboptimal Light Conditions Influence Source-Sink Metabolism during Flowering.

    PubMed

    Christiaens, Annelies; De Keyser, Ellen; Pauwels, Els; De Riek, Jan; Gobin, Bruno; Van Labeke, Marie-Christine

    2016-01-01

    Reliance on carbohydrates during flower forcing was investigated in one early and one late flowering cultivar of azalea (Rhododendron simsii hybrids). Carbohydrate accumulation, invertase activity, and expression of a purported sucrose synthase gene (RsSUS) was monitored during flower forcing under suboptimal (natural) and optimal (supplemental light) light conditions, after a cold treatment (7°C + dark) to break flower bud dormancy. Post-production sucrose metabolism and flowering quality was also assessed. Glucose and fructose concentrations and invertase activity increased in petals during flowering, while sucrose decreased. In suboptimal light conditions RsSUS expression in leaves increased as compared to optimal light conditions, indicating that plants in suboptimal light conditions have a strong demand for carbohydrates. However, carbohydrates in leaves were markedly lower in suboptimal light conditions compared to optimal light conditions. This resulted in poor flowering of plants in suboptimal light conditions. Post-production flowering relied on the stored leaf carbon, which could be accumulated under optimal light conditions in the greenhouse. These results show that flower opening in azalea relies on carbohydrates imported from leaves and is source-limiting under suboptimal light conditions. PMID:26973689

  14. Solar Absorption Refrigeration System for Air-Conditioning of a Classroom Building in Northern India

    NASA Astrophysics Data System (ADS)

    Agrawal, Tanmay; Varun; Kumar, Anoop

    2015-10-01

    Air-conditioning is a basic tool to provide human thermal comfort in a building space. The primary aim of the present work is to design an air-conditioning system based on vapour absorption cycle that utilizes a renewable energy source for its operation. The building under consideration is a classroom of dimensions 18.5 m × 13 m × 4.5 m located in Hamirpur district of Himachal Pradesh in India. For this purpose, cooling load of the building was calculated first by using cooling load temperature difference method to estimate cooling capacity of the air-conditioning system. Coefficient of performance of the refrigeration system was computed for various values of strong and weak solution concentration. In this work, a solar collector is also designed to provide required amount of heat energy by the absorption system. This heat energy is taken from solar energy which makes this system eco-friendly and sustainable. A computer program was written in MATLAB to calculate the design parameters. Results were obtained for various values of solution concentrations throughout the year. Cost analysis has also been carried out to compare absorption refrigeration system with conventional vapour compression cycle based air-conditioners.

  15. Local and regional variability in snow conditions in northern Finland: A reindeer herding perspective.

    PubMed

    Rasmus, Sirpa; Kivinen, Sonja; Bavay, Mathias; Heiskanen, Janne

    2016-05-01

    Weather station measurements were used to force the SNOWPACK snow model and combined with reindeer herders' experiences to study the local and regional variations in snow conditions in a Finnish reindeer herding area for the 1981-2010 period. Winter conditions varied significantly between the four selected herding districts and between open and forest environments within the districts. The highest snow depths and densities, the thicknesses of ground ice, and the lengths of snow cover period were generally found in the northernmost districts. The snow depths showed the strongest regional coherence, whereas the thicknesses of ground ice were weakly correlated among the districts. The local variation in snow depths was higher than the regional variation and limits for rare or exceptional events varied notably between different districts and environments. The results highlight that forests diversify snow and foraging conditions, e.g., ground ice rarely forms simultaneously in different environments. Sufficient and diverse forest pastures are important during the critical winter season if reindeer herding is pursued on natural grazing grounds also in the future. PMID:26754168

  16. Influence of harvest time on fuel characteristics of five potential energy crops in northern China.

    PubMed

    Xiong, Shaojun; Zhang, Quan-Guo; Zhang, Da-Yong; Olsson, Rolf

    2008-02-01

    Five potential energy crops in northern China were examined for fuel characteristics over different harvest times to test whether or not a delayed harvest improves fuel quality in a semiarid area in China as is the case in northern Europe and North America. The five crops include indigo bush (Amorpha fruticosa), sand willow (Salix cheilophila), switch grass (Panicum virgatum), reed canary grass (Phalaris arundinacea), and sainfoin (Onobrychis viciifolia). These crops are considered as fuels for thermal conversion. From September 2002 to April 2003, biomass was sampled monthly, and the effects of harvest time on the fuel characteristics of the five crops were studied. With respect to ash and some undesired element contents in biomass, a delayed harvest in spring resulted in a better fuel quality than a traditional harvest in autumn. Of the five species, indigo bush and sand willow had the lowest ash contents when harvested in spring. Switch grass is a promising herbaceous energy crop in semiarid areas in terms of its yield, fuel characteristics, and low water use. Chlorine had the most significant correlation with harvest time and ash content in the biomass. In a comparison with the biofuel crops in Europe and North America, a much higher proportion of chlorine was found in all examined plants. The results from this study indicate that an energy crop with delayed harvest may extend fuel resources and conserve soil in semiarid regions in northern China, practices that will help maintain and improve economical and ecological sustainability. PMID:17382539

  17. Influence of dynamic conditions on biofilm formation by staphylococci.

    PubMed

    Stepanović, S; Vuković, D; Jezek, P; Pavlović, M; Svabic-Vlahović, M

    2001-07-01

    The modified microtiter plate test was used to investigate biofilm formation by staphylococci under both static and dynamic conditions. The quantity of biofilm produced under static conditions was used as a reference. Dynamic conditions, which were achieved by incubating microtiter plates on a horizontal shaker with and without the presence of glass beads in wells, either reduced biofilm formation or left it unchanged. Dynamic conditions particularly affected the capacity of certain species to produce biofilm: these species included the causative agents of infections associated with a foreign body (Staphylococcus epidermidis, Staphylococcus aureus). On the basis of these results, dynamic conditions should be included as a parameter for evaluating biofilm formation by staphylococci in vitro. PMID:11561809

  18. Conditions Influencing Faculty Voting in Collective Bargaining Elections.

    ERIC Educational Resources Information Center

    Bornheimer, Deane G.

    1985-01-01

    The factors that influenced voting behavior in two faculty union defeats at New York University are examined. The importance of the swing votes cast in a run-off election by the members of a previously defeated third party is discussed. (Author/MLW)

  19. Conditions that Influence Drivers' Yielding Behavior for Uncontrolled Crossings

    ERIC Educational Resources Information Center

    Bourquin, Eugene; Emerson, Robert Wall; Sauerburger, Dona

    2011-01-01

    Pedestrians with visual impairments need to cross streets where traffic signals and traffic signage are not present. This study examined the influences of several interventions, including a pedestrian's use of a mobility cane, on the behavior of drivers when they were expected to yield to a pedestrian crossing at an uncontrolled crossing.…

  20. Influence of initial conditions on compressible vorticity dynamics

    NASA Astrophysics Data System (ADS)

    Virk, D.; Hussain, F.

    1993-11-01

    Prompted by the lack of a unique choice of pressure ( P) and density (ρ) fields for a compressible free vortex and by the observed dependence of turbulence dynamics on initial P and ρ in compressible simulations, we address the effects of initial conditions on the evolution of a single vortex, on the prototypical phenomenon of vortex reconnection, and on two-dimensional turbulence. Two previous choices of initial conditions used for numerical simulations of compressible turbulence have been: (i) both P and ρ uniform (constant initial conditions, CIC), and (ii) uniform ρ with P determined from the Poisson equation (constant density initial conditions, CDIC). We find these initial conditions to be inappropriate for compressible vorticity dynamics studies. Specifically, in compressible reconnection, the effects of baroclinic vorticity generation and shocklet formation cancel each other during early evolution for CDIC, thus leading to almost incompressible behavior. Although CIC captures compressibility effects, it incorrectly changes the initial vorticity distribution by introducing strong acoustic transients, thereby significantly altering the evolving dynamics. Here, a new initial condition, called polytropic initial condition (PIC), is proposed, for which the Poisson equation is solved for initially polytropically related P and ρ fields. PIC provides P and ρ distributions within vortices which are consistent with those observed in shock-wedge interaction experiment and also leads to compressible solutions with no acoustic transients. At low Mach number ( M), we show that the effects of all these three initial conditions can be predicted by low- M asymptotic theories of the Navier-Stokes equations. At high M, it is shown here that inappropriate initial conditions may alter the evolutionary dynamics and, hence, lead to wrong conclusions regarding compressibility effects. We argue that PIC is a more appropriate choice.

  1. Beak condition and cage density determine abundance and spatial distribution of northern fowl mites, Ornithonyssus sylviarum, and chicken body lice, Menacanthus stramineus, on caged laying hens.

    PubMed

    Mullens, B A; Chen, B L; Owen, J P

    2010-12-01

    Adult White Leghorn hens (Hy-Line strain W-36) were inoculated with either northern fowl mites or chicken body lice, and the ectoparasite populations were monitored over periods of 9 to 16 wk. Two beak conditions (beak trimmed or beak intact) and 2 housing densities (1 or 2 hens per 25 × 31 cm suspended wire cage) were tested. Populations of both ectoparasites were at least 10 times lower on beak-intact hens compared with populations on beak-trimmed hens. Cage density did not influence mite numbers, but higher numbers of lice (2 to 3 times) developed on hens held at the higher cage density. Louse distribution on the body and louse population age structure were also influenced by host beak condition. Beak-intact hens had a higher proportion of lice under the wings, whereas beak-trimmed hens had the majority of lice on the lower abdomen. Louse populations on beak-trimmed hens also comprised relatively more immature stages than populations found on beak-intact hens. The effects are likely related to decreased grooming efficiency by beak-trimmed hens and, in the case of lice, the higher host density. The high mite and louse populations on most commercial caged laying hens are probably a direct result of beak trimming. However, selection of more docile breeds that can be held without trimming may allow the hens themselves to reduce ectoparasites below economically damaging levels. This could benefit producers, animal welfare advocates, and human health by reducing 1) costs of beak trimming, 2) pesticide treatment costs (including human and bird chemical exposure concerns), and 3) objections to beak trimming from the animal welfare community. PMID:21076093

  2. Influence of thermal conditioning media on Charpy specimen test temperature

    SciTech Connect

    Nanstad, R.K.; Swain, R.L.; Berggren, R.G.

    1989-01-01

    The Charpy V-notch (CVN) impact test is used extensively for determining the toughness of structural materials. Research programs in many technologies concerned with structural integrity perform such testing to obtain Charpy energy vs temperature curves. American Society for Testing and Materials Method E 23 includes rather strict requirements regarding determination and control of specimen test temperature. It specifies minimum soaking times dependent on the use of liquids or gases as the medium for thermally conditioning the specimen. The method also requires that impact of the specimen occur within 5 s removal from the conditioning medium. It does not, however, provide guidance regarding choice of conditioning media. This investigation was primarily conducted to investigate the changes in specimen temperature which occur when water is used for thermal conditioning. A standard CVN impact specimen of low-alloy steel was instrumented with surface-mounted and embedded thermocouples. Dependent on the media used, the specimen was heated or cooled to selected temperatures in the range {minus}100 to 100{degree}C using cold nitrogen gas, heated air, acetone and dry ice, methanol and dry ice, heated oil, or heated water. After temperature stabilization, the specimen was removed from the conditioning medium while the temperatures were recorded four times per second from all thermocouples using a data acquisition system and a computer. The results show that evaporative cooling causes significant changes in the specimen temperatures when water is used for conditioning. Conditioning in the other media did not result in such significant changes. The results demonstrate that, even within the guidelines of E 23, significant test temperature changes can occur which may substantially affect the Charpy impact test results if water is used for temperature conditioning. 7 refs., 11 figs.

  3. Do breeding phase and detection distance influence the effective area surveyed for northern goshawks?

    USGS Publications Warehouse

    Roberson, A.M.; Andersen, D.E.; Kennedy, P.L.

    2005-01-01

    Broadcast surveys using conspecific calls are currently the most effective method for detecting northern goshawks (Accipiter gentilis) during the breeding season. These surveys typically use alarm calls during the nestling phase and juvenile food-begging calls during the fledgling-dependency phase. Because goshawks are most vocal during the courtship phase, we hypothesized that this phase would be an effective time to detect goshawks. Our objective was to improve current survey methodology by evaluating the probability of detecting goshawks at active nests in northern Minnesota in 3 breeding phases and at 4 broadcast distances and to determine the effective area surveyed per broadcast station. Unlike previous studies, we broadcast calls at only 1 distance per trial. This approach better quantifies (1) the relationship between distance and probability of detection, and (2) the effective area surveyed (EAS) per broadcast station. We conducted 99 broadcast trials at 14 active breeding areas. When pooled over all distances, detection rates were highest during the courtship (70%) and fledgling-dependency phases (68%). Detection rates were lowest during the nestling phase (28%), when there appeared to be higher variation in likelihood of detecting individuals. EAS per broadcast station was 39.8 ha during courtship and 24.8 ha during fledgling-dependency. Consequently, in northern Minnesota, broadcast stations may be spaced 712m and 562 m apart when conducting systematic surveys during courtship and fledgling-dependency, respectively. We could not calculate EAS for the nestling phase because probability of detection was not a simple function of distance from nest. Calculation of EAS could be applied to other areas where the probability of detection is a known function of distance.

  4. A possible influence of recent polar stratospheric coolings on the troposphere in the northern hemisphere winter

    SciTech Connect

    Kunihiko Kodera; Koji Yamazaki )

    1994-05-01

    The authors study possible correlations between stratospheric cooling trends and increased circulation in the northern hemispheric troposphere in the period 1979 to 1992. These changes are compared with the effect of stratospheric heating which resulted from several aerosol injections from major volcanic activity during this period. These injections act much like an external forcing function applied to the stratosphere, and allow one to infer information on the response of the stratosphere/troposphere system to this dynamic input. For both cases one can observe perturbations in the zonal/mean zonal winds propogating into the troposphere.

  5. Influence of impurity gases and operating conditions on PAFC performance

    SciTech Connect

    Hirai, K.; Iwasa, N.; Suzuki, M.; Okada, O.

    1996-12-31

    On-site Phosphoric Acid Fuel Cell (PAFC) Cogeneration system is installed at various test sites, such as at underground parking lot, within chemical plant premises and near urban streets. Since in the current PAFC system, cathode air is supplied to the cell with no particular pretreatment, impurity gases in the air might influence on cell performance. We have investigated the influence of various impurity gases in the cathode gas, on sub-scale single cells, and have found that NO{sub 2}, SO{sub 2} and toluene affect negatively on cell performance. The results of these experiments and the conceivable mechanism of these effects on cell degradation are reported. We have also investigated the influence of other operating parameters, such as temperature, current density, fuel utilization on cell performance. From these experiments, we have found that operating temperature is a significant factor, which mainly determines cell voltage decline rate. The results of sub-scale single cell tests and a short-stack verification test are also reported.

  6. Gambling, housing conditions, community contexts and child health in remote indigenous communities in the Northern Territory, Australia

    PubMed Central

    2012-01-01

    Background Recent government reports have identified gambling, along with alcohol abuse, drug abuse and pornography, as contributing to child neglect and abuse in Indigenous communities in the Northern Territory (NT). These reports also identify gaps in empirical evidence upon which to base sound policy. To address this shortfall, data from ten remote Indigenous communities was analysed to determine the relationship between gambling problems, housing conditions, community contexts and child health in indigenous communities. Methods Logistic regression was used to assess associations between gambling problems, community contexts, housing conditions and child health. Separate multivariable models were developed for carer reported gambling problems in houses and six child health outcomes. Results Carer reported gambling problems in households across the ten communities ranged from 10% to 74%. Inland tropical communities had the highest level of reported gambling problems. Less access to a doctor in the community showed evidence of a multivariable adjusted association with gambling problems in houses. No housing variables showed evidence for a multivariable association with reported gambling problems. There was evidence for gambling problems having a multivariable adjusted association with carer report of scabies and ear infection in children. Conclusions The analyses provide evidence that gambling is a significant problem in Indigenous communities and that gambling problems in households is related to poor child health outcomes. A comprehensive (prevention, treatment, regulation and education) public health approach to harm minimisation associated with gambling amongst the Indigenous population is required that builds on current normative community regulation of gambling. PMID:22632458

  7. Pre-development conditions to assess the impact of growth in an urbanizing watershed in Northern Virginia

    NASA Astrophysics Data System (ADS)

    Kumar, Saurav; Godrej, Adil N.; Grizzard, Thomas J.

    2016-09-01

    Pre-development conditions are an easily understood state to which watershed nonpoint nutrient reduction targets may be referenced. Using the pre-development baseline, a "developed-excess" measure may be computed for changes due to anthropogenic development. Developed-excess is independent of many geographical, physical, and hydrological characteristics of the region and after normalization by area may be used for comparison among various sub-sets of the watershed, such as jurisdictions or land use types. We have demonstrated this method by computing pre-development nitrogen and phosphorus loads entering the Occoquan Reservoir from its tributary watershed in Northern Virginia. The pre-development loads in this study were computed using the calibrated water quality models for the period 2002-2007. Current forest land was used as a surrogate for pre-development land use conditions for the watershed and developed-excess was estimated for fluvial loads of Total Inorganic Nitrogen (TIN) and Orthophosphate-Phosphorus (OP) by subtracting simulated predevelopment loads from observed loads. It was observed that within the study period (2002-2007), the average annual developed-excess represented about 30% of the TIN and OP average annual loads exported to the reservoir. Comparison of the two disturbed land use types, urban and agricultural, showed that urban land uses exported significantly more excess nonpoint nutrient load per unit area than agricultural land uses.

  8. A hierarchical Bayesian regional model for nonstationary precipitation extremes in Northern California conditioned on tropical moisture exports

    NASA Astrophysics Data System (ADS)

    Steinschneider, Scott; Lall, Upmanu

    2015-03-01

    Warm, moist, and longitudinally confined tropical air masses are being linked to some of the most extreme precipitation and flooding events in the midlatitudes. The interannual frequency and intensity of such atmospheric rivers (ARs), or tropical moisture exports (TMEs), are connected to the risk of extreme precipitation events in areas where moisture convergence occurs. This study presents a nonstationary, regional frequency analysis of precipitation extremes in Northern California that is conditioned on the interannual variability of TMEs entering the region. Parameters of a multisite peaks-over-threshold model are allowed to vary conditional on the integrated moisture delivery from TMEs over the area. Parameters are also related to time-invariant, local characteristics to facilitate regionalization to ungaged sites. The model is developed and calibrated in a hierarchical Bayesian framework to support partial pooling and enhance regionalization skill. The model is cross validated along with two alternative, increasingly parsimonious formulations to assess the additional skill provided by the covariates. Climate diagnostics are also used to better understand the instances where TMEs fail to explain variations in rainfall extremes to provide a path forward for further model improvement. The modeling structure is designed to link seasonal forecasting and long-term projections of TMEs directly to regional models of extremes used for risk estimation. Results suggest that the inclusion of TME-based information greatly improves the characterization of extremes, particularly for their frequency of occurrence. Diagnostics indicate that the model could be further improved by considering an index for frontal systems as an additional covariate.

  9. Body condition and forage type influence intramuscular and rump fat, and reproductive performance of postpartum Brahman-influenced cows

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multiparous Brahman-influenced cows were managed to achieve marginal (BCS = 4.9 ± 0.1; n = 55) or moderate (BCS = 6.5 ± 0.1; n = 55) body condition (BC) to determine the influence of forage type on estrous characteristics, intramuscular fat percentage (IMF), rump fat (RF), and reproductive performan...

  10. The influence of living conditions on adolescent girls’ health

    PubMed Central

    Sundler, Annelie Johansson; Ekebergh, Margaretha

    2012-01-01

    Adolescence is described by the Swedish National Board of Health and Welfare as the healthiest period in life. However, adolescent girls differ in that they self-report that their health decreases with age. The aim of this hermeneutical study was to describe the meaning of living conditions in relation to adolescent girls’ health. Guided by principles of reflective lifeworld research, 15 interviews with adolescent girls were analysed. The result section consists of four narratives with their existential interpretations illustrating different ways of approaching living conditions and their meaning for health and well-being. The narratives are: Approaching everyday life in a balanced way—feeling harmonious; approaching everyday life with ambiguity—feeling confused; approaching everyday life as an intellectual project—striving for control; approaching everyday life as a struggle—feeling forlorn. In addition, a comprehensive understanding was developed by using the lifeworld dimensions: lived body, lived room, lived time, and lived relations. These dimensions may deepen the understanding of important parts of those living conditions which are meaningful for the girls’ health and well-being. By using the dimensions, complex living conditions have been explored and the meaning of different parts clarified. The girls’ thoughts and feelings are often ambiguous and sometimes contradictory, depending on the situation. The health of adolescent girls needs to be understood against the background of their experiences of living conditions. One way to support their health and well-being seems to be to supply them with forums where they can talk about their living conditions. PMID:23237626

  11. Influence of vegetation on water isotope partitioning across different northern headwater catchments

    NASA Astrophysics Data System (ADS)

    Gabor, R. S.; Tetzlaff, D.; Buttle, J. M.; Carey, S. K.; Laudon, H.; Mitchell, C. P. J.; McNamara, J. P.; Soulsby, C.

    2014-12-01

    The hydrology of high latitude catchments is sensitive to small changes in temperature, and likely to be impacted by changes in climate. Vegetation water usage can play a large role in catchment hydrologic pathways, affecting how water is stored, released, and partitioned within a landscape. Thus a better understanding of how vegetation impacts water partitioning in northern catchments can help us understand how climate change will impact high-latitude hydrology. As part of the VeWa project, five catchments were chosen between 44oN and 64oN in Europe and North America, to compare the role of vegetation in the movement of water across northern landscapes. These catchments vary in aspect as well as extent of snowpack and their vegetative landscapes include heather moorland, coniferous and deciduous forests, mixed grass, and tundra landscapes. Importantly, all the catchments have records of stable isotopes in different waters of the system. An initial comparison of the water isotopes in these catchments demonstrates variation between the catchments, with the lower latitude sites showing more fractionation suggestive of evapotranspiration. While all catchments show a depletion of heavy isotopes in the spring, the depletion is most evident in catchments with a heavier snowpack. The vegetative growing season during the summer months shows the greatest impact of evapotranspiration on isotopes, indicating that an increased summer in a warmer climate would likely alter water partitioning and storage dynamics in these regions.

  12. INFLUENCE OF PH AND REDOX CONDITIONS ON COPPER LEACHING

    EPA Science Inventory

    Leaching behavior of metals from a mineral processing waste at varying pH and redox conditions was studies. Effect of combinations of pH and Eh on leaching of copper is described. Leaching of copper was found to be dependent on both pH and Eh. Higher concentrations of Cu were ...

  13. Influencing Children's Pregambling Game Playing via Conditional Discrimination Training

    ERIC Educational Resources Information Center

    Johnson, Taylor E.; Dixon, Mark R.

    2009-01-01

    Past research has demonstrated a transformation of stimulus functions under similar conditions using gambling tasks and adults (e.g., Zlomke & Dixon, 2006), and the present study attempted to extend this research. Experimenters exposed 7 children (ages 7 to 10 years) to a simulated board game with concurrently available dice differing only by…

  14. Influence of pavement condition on horizontal curve safety.

    PubMed

    Buddhavarapu, Prasad; Banerjee, Ambarish; Prozzi, Jorge A

    2013-03-01

    Crash statistics suggest that horizontal curves are the most vulnerable sites for crash occurrence. These crashes are often severe and many involve at least some level of injury due to the nature of the collisions. Ensuring the desired pavement surface condition is one potentially effective strategy to reduce the occurrence of severe accidents on horizontal curves. This study sought to develop crash injury severity models by integrating crash and pavement surface condition databases. It focuses on developing a causal relationship between pavement condition indices and severity level of crashes occurring on two-lane horizontal curves in Texas. In addition, it examines the suitability of the existing Skid Index for safety maintenance of two-lane curves. Significant correlation is evident between pavement condition and crash injury severity on two-lane undivided horizontal curves in Texas. Probability of a crash becoming fatal is appreciably sensitive to certain pavement indices. Data suggested that road facilities providing a smoother and more comfortable ride are vulnerable to severe crashes on horizontal curves. In addition, the study found that longitudinal skid measurement barely correlates with injury severity of crashes occurring on curved portions. The study recommends exploring the option of incorporating lateral friction measurement into Pavement Management System (PMS) databases specifically at curved road segments. PMID:23298704

  15. Use of color maps and wavelet coherence to discern seasonal and interannual climate influences on streamflow variability in northern catchments

    NASA Astrophysics Data System (ADS)

    Carey, Sean K.; Tetzlaff, Doerthe; Buttle, Jim; Laudon, Hjalmar; McDonnell, Jeff; McGuire, Kevin; Seibert, Jan; Soulsby, Chris; Shanley, Jamie

    2013-10-01

    The higher midlatitudes of the northern hemisphere are particularly sensitive to change due to the important role the 0°C isotherm plays in the phase of precipitation and intermediate storage as snow. An international intercatchment comparison program called North-Watch seeks to improve our understanding of the sensitivity of northern catchments to change by examining their hydrological and biogeochemical variability and response. Here eight North-Watch catchments located in Sweden (Krycklan), Scotland (Girnock and Strontian), the United States (Sleepers River, Hubbard Brook, and HJ Andrews), and Canada (Dorset and Wolf Creek) with 10 continuous years of daily precipitation and runoff data were selected to assess daily to seasonal coupling of precipitation (P) and runoff (Q) using wavelet coherency, and to explore the patterns and scales of variability in streamflow using color maps. Wavelet coherency revealed that P and Q were decoupled in catchments with cold winters, yet were strongly coupled during and immediately following the spring snowmelt freshet. In all catchments, coupling at shorter time scales occurred during wet periods when the catchment was responsive and storage deficits were small. At longer time scales, coupling reflected coherence between seasonal cycles, being enhanced at sites with enhanced seasonality in P. Color maps were applied as an alternative method to identify patterns and scales of flow variability. Seasonal versus transient flow variability was identified along with the persistence of that variability on influencing the flow regime. While exploratory in nature, this intercomparison exercise highlights the importance of climate and the 0°C isotherm on the functioning of northern catchments.

  16. A GIS-based automated procedure for landslide susceptibility mapping by the Conditional Analysis method: the Baganza valley case study (Italian Northern Apennines)

    NASA Astrophysics Data System (ADS)

    Clerici, Aldo; Perego, Susanna; Tellini, Claudio; Vescovi, Paolo

    2006-08-01

    Among the many GIS based multivariate statistical methods for landslide susceptibility zonation, the so called “Conditional Analysis method” holds a special place for its conceptual simplicity. In fact, in this method landslide susceptibility is simply expressed as landslide density in correspondence with different combinations of instability-factor classes. To overcome the operational complexity connected to the long, tedious and error prone sequence of commands required by the procedure, a shell script mainly based on the GRASS GIS was created. The script, starting from a landslide inventory map and a number of factor maps, automatically carries out the whole procedure resulting in the construction of a map with five landslide susceptibility classes. A validation procedure allows to assess the reliability of the resulting model, while the simple mean deviation of the density values in the factor class combinations, helps to evaluate the goodness of landslide density distribution. The procedure was applied to a relatively small basin (167 km2) in the Italian Northern Apennines considering three landslide types, namely rotational slides, flows and complex landslides, for a total of 1,137 landslides, and five factors, namely lithology, slope angle and aspect, elevation and slope/bedding relations. The analysis of the resulting 31 different models obtained combining the five factors, confirms the role of lithology, slope angle and slope/bedding relations in influencing slope stability.

  17. Post-bomb coral Δ14C record from Iki Island, Japan: possible evidence of oceanographic conditions on the northern East China Sea shelf

    NASA Astrophysics Data System (ADS)

    Mitsuguchi, Takehiro; Hirota, Masashi; Paleo Labo AMS Dating Group; Yamazaki, Atsuko; Watanabe, Tsuyoshi; Yamano, Hiroya

    2016-07-01

    Nansei Islands area; (2) the shelf-surface water is conveyed from the northern ECS to Iki Island by the Tsushima Current. Thus, it can be suggested that the post-bomb coral Δ14C record from Iki Island reflects oceanographic conditions of the northern ECS shelf.

  18. Orientation, composition, and entrapment conditions of fluid inclusions in the footwall of the northern Snake Range detachment, Nevada

    NASA Astrophysics Data System (ADS)

    Carter, Matthew J.; Siebenaller, Luc; Teyssier, Christian

    2015-12-01

    Footwall rocks of the northern Snake Range detachment fault (Hampton and Hendry's Creeks) offer exposures of quartzite mylonites (sub-horizontal foliation) that were permeated by surface fluids. An S-C-C‧ mylonitic fabric is defined by dynamically recrystallized quartz and mica. Electron backscatter diffraction analyses indicate a strong preferred orientation of quartz that is overprinted by two sets of sub-vertical, ESE and NNE striking fractures. Analyses of sets of three perpendicular thin sections indicate that fluid inclusions (FIs) are arranged according to macroscopic fracture patterns. FIs associated with NNE and ESE-striking fractures coevally trapped unmixed CO2 and H2O-rich fluids at conditions near the critical CO2-H2O solvus, giving minimum trapping conditions of T = 175-200 °C and ∼100 MPa H2O-rich FIs trapped along ESE-trending microcracks in single crystals of quartz may have been trapped at conditions as low as 150 °C and 50 MPa indicating the latest microfracturing and annealing of quartz in an overall extensional system. Results suggest that the upper crust was thin (4-8 km) during FI trapping and had an elevated geotherm (>50 °C/km). Footwall rocks that have been exhumed through the brittle-ductile transition in such extensional systems experience both brittle and crystal-plastic deformation that may allow for circulation of meteoric fluids and grain-scale fluid-rock interactions.

  19. The effect of northern fowl mite (Ornithonyssus sylviarum) infestation on hen physiology, physical condition, and egg quality.

    PubMed

    Vezzoli, Giuseppe; King, Annie J; Mench, Joy A

    2016-05-01

    The northern fowl mite (NFM),Ornithonyssus sylviarum, is the most common ectoparasite of laying hens in North America. Infestation can cause a reduction in egg production, egg weights, and feed conversion efficiency. However, there is a lack of information on the effects of NFM on hen physiology, physical condition, and egg quality. Singly caged beak-trimmed White Leghorn hens (N=32) were infested with mites at 25 wk of age. The condition of each hen was assessed at wk 0 (infestation) and wk 5 and 7 post-infestation to determine comb temperatures and feather, skin, and comb condition. Heterophil-lymphocyte (H/L) ratios and body weight (BW) were evaluated at wk 0 and wk 1, 3, 5, and 7 post-infestation. Egg weight, egg specific gravity, yolk color, Haugh unit (HU), and eggshell thickness were determined prior to infestation (wk -1) and at 1, 3, 5, and 7 wk post-infestation. The H/L ratio (P<0.0001), HU (P<0.0001), and egg specific gravity (P=0.001) were lowest, and the egg yolk color was lightest (P=0.087) at wk 5, the peak of infestation. At wk 5 and 7, more than 65% of the hens had red skin and more than 75% had scabs on the vent; in addition more than 84% had grey-black vent feathers. There were no effects of infestation on comb color, comb temperature, feather cover, BW, or eggshell thickness. It was concluded that infestation with NFM has negative effects on interior egg quality and hen integument. A decrease in H/L ratio was also observed at the peak of infestation. However, the effects of NFM on the immune system are unclear, and H/L ratio might not be a good stress measure in hens highly infested with NFM. PMID:26944982

  20. Northern Hemisphere atmospheric influence of the solar proton events and ground level enhancement in January 2005

    NASA Astrophysics Data System (ADS)

    Jackman, C. H.; Marsh, D. R.; Vitt, F. M.; Roble, R. G.; Randall, C. E.; Bernath, P. F.; Funke, B.; López-Puertas, M.; Versick, S.; Stiller, G. P.; Tylka, A. J.; Fleming, E. L.

    2011-03-01

    Solar eruptions in early 2005 led to a substantial barrage of charged particles on the Earth's atmosphere during the 16-21 January period. Proton fluxes were greatly increased during these several days and led to the production of HOx (H, OH, HO2) and NOx (N, NO, NO2), which then caused the destruction of ozone. We focus on the Northern polar region, where satellite measurements and simulations with the Whole Atmosphere Community Climate Model (WACCM3) showed large enhancements in mesospheric HOx and NOx constituents, and associated ozone reductions, due to these solar proton events (SPEs). The WACCM3 simulations show enhanced short-lived OH throughout the mesosphere in the 60-82.5° N latitude band due to the SPEs for most days in the 16-21 January 2005 period, in reasonable agreement with the Aura Microwave Limb Sounder (MLS) measurements. Mesospheric HO2 is also predicted to be increased by the SPEs, however, the modeled HO2 results are somewhat larger than the MLS measurements. These HOx enhancements led to huge predicted and MLS-measured ozone decreases of greater than 40% throughout most of the northern polar mesosphere during the SPE period. Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) measurements of hydrogen peroxide (H2O2) show increases throughout the stratosphere with highest enhancements of about 60 pptv in the lowermost mesosphere over the 16-18 January 2005 period due to the solar protons. WACCM3 predictions indicate H2O2 enhancements over the same time period of more than twice that amount. Measurements of nitric acid (HNO3) by both MLS and MIPAS show an increase of about 1 ppbv above background levels in the upper stratosphere during 16-29 January 2005. WACCM3 simulations show only minuscule HNO3 changes in the upper stratosphere during this time period. Polar mesospheric enhancements of NOx are computed to be greater than 50 ppbv during the SPE period due to the small loss rates during winter. Computed NOx increases

  1. Northern Hemisphere atmospheric influence of the solar proton events and ground level enhancement in January 2005

    NASA Astrophysics Data System (ADS)

    Jackman, C. H.; Marsh, D. R.; Vitt, F. M.; Roble, R. G.; Randall, C. E.; Bernath, P. F.; Funke, B.; López-Puertas, M.; Versick, S.; Stiller, G. P.; Tylka, A. J.; Fleming, E. L.

    2011-07-01

    Solar eruptions in early 2005 led to a substantial barrage of charged particles on the Earth's atmosphere during the 16-21 January period. Proton fluxes were greatly increased during these several days and led to the production of HOx (H, OH, HO2) and NOx (N, NO, NO2), which then caused the destruction of ozone. We focus on the Northern polar region, where satellite measurements and simulations with the Whole Atmosphere Community Climate Model (WACCM3) showed large enhancements in mesospheric HOx and NOx constituents, and associated ozone reductions, due to these solar proton events (SPEs). The WACCM3 simulations show enhanced short-lived OH and HO2 concentrations throughout the mesosphere in the 60-82.5° N latitude band due to the SPEs for most days in the 16-21 January 2005 period, somewhat higher in abundance than those observed by the Aura Microwave Limb Sounder (MLS). These HOx enhancements led to huge predicted and MLS-measured ozone decreases of greater than 40 % throughout most of the northern polar mesosphere during the SPE period. Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) measurements of hydrogen peroxide (H2O2) show increases throughout the stratosphere with highest enhancements of about 60 pptv in the lowermost mesosphere over the 16-18 January 2005 period due to the solar protons. WACCM3 predictions indicate H2O2 enhancements over the same time period of about three times that amount. Measurements of nitric acid (HNO3) by both MLS and MIPAS show an increase of about 1 ppbv above background levels in the upper stratosphere during 16-29 January 2005. WACCM3 simulations show only minuscule HNO3 increases (<0.05 ppbv) in the upper stratosphere during this time period. Polar mesospheric enhancements of NOx are computed to be greater than 50 ppbv during the SPE period due to the small loss rates during winter. Computed NOx increases, which were statistically significant at the 95 % level, lasted about a month past the SPEs

  2. Can environmental conditions experienced in early life influence future generations?

    PubMed Central

    Burton, Tim; Metcalfe, Neil B.

    2014-01-01

    The consequences of early developmental conditions for performance in later life are now subjected to convergent interest from many different biological sub-disciplines. However, striking data, largely from the biomedical literature, show that environmental effects experienced even before conception can be transmissible to subsequent generations. Here, we review the growing evidence from natural systems for these cross-generational effects of early life conditions, showing that they can be generated by diverse environmental stressors, affect offspring in many ways and can be transmitted directly or indirectly by both parental lines for several generations. In doing so, we emphasize why early life might be so sensitive to the transmission of environmentally induced effects across generations. We also summarize recent theoretical advancements within the field of developmental plasticity, and discuss how parents might assemble different ‘internal’ and ‘external’ cues, even from the earliest stages of life, to instruct their investment decisions in offspring. In doing so, we provide a preliminary framework within the context of adaptive plasticity for understanding inter-generational phenomena that arise from early life conditions. PMID:24807254

  3. Displacement and HIV: Factors Influencing Antiretroviral Therapy Use by Ethnic Shan Migrants in Northern Thailand.

    PubMed

    Murray, Jordan K; DiStefano, Anthony S; Yang, Joshua S; Wood, Michele M

    2016-01-01

    Migrant populations face increased HIV vulnerabilities, including limited access to antiretroviral therapy. Civil conflict in Myanmar has displaced thousands of people from the minority Shan ethnic group into northern Thailand, where they bear a disproportionate HIV burden. To identify barriers and facilitators of antiretroviral therapy use in this population, we conducted a rapid ethnographic assessment and case study with a clinical sample of Shan migrants receiving treatment for HIV in a district hospital in Chiang Mai, Thailand, Thai nurses providing their care, and health care administrators (n = 23). Barriers included fears of arrest and deportation, communication difficulties, perceived social marginalization, limited HIV knowledge, and lack of finances. Facilitating factors included hospital-based migrant registration services and community outreach efforts involving support group mobilization, referral practices, and radio broadcasts. These findings provided a contextualized account to inform policies, community interventions, and nursing practice to increase treatment access for minority migrant groups. PMID:27188762

  4. Analyzing the Influence of Tropical Deforestation on the Northern Hemisphere Climate Through Atmospheric Teleconnections

    NASA Astrophysics Data System (ADS)

    Snyder, P. K.; Hitchman, M. H.; Foley, J. A.

    2004-12-01

    Previous studies have identified the regional-scale climate response to tropical deforestation through changes to the biophysical exchanges of water, energy, and momentum between the land surface and the atmosphere; however, little is known about the effects of tropical deforestation on the global climate. Current research has focused on climate responses in the extratropics with little analyses of the mechanisms responsible for propagating the signal out of the tropics. Here, we present a detailed study of the physical processes important in propagating a signal resulting from deforestation out of the tropics to the Northern Hemisphere in winter. Through complete deforestation of the tropics we analyze changes to the deep moist convection and reductions in high-level outflow as well as the anomalous forcing of Rossby waves out of the tropics. Our study indicates that an anomalous Rossby wave forcing resulting from tropical deforestation modifies the East Asian Jet strength and structure as well as other features of the Northern Hemisphere mean circulation patterns. Furthermore, our results indicate that tropical deforestation can amplify different modes of the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) through a redistribution of atmospheric mass caused by fundamental changes to the strength and positioning of the storm tracks and synoptic eddy activity. Different modes of variability cause different climate responses across Siberia and result in anomalous changes to the low-level winds that can significantly enhance the advection of warm air into Eurasia from the south and west. While theoretical, our approach illustrates the potentially important processes connecting regional-scale changes in the tropical climate to regional-scale changes in the extratropics.

  5. Susceptibility of volcanic ash-influenced soil in Northern Idaho to mechanical compaction. Forest Service research note

    SciTech Connect

    Page-Dumroese, D.S.

    1993-02-01

    Timber harvesting and mechanical site preparation can reduce site productivity if they excessively disturb or compact the soil. Volcanic ash-influenced soils with low undisturbed bulk densities and rock content are particularly susceptible. The study evaluates the effects of harvesting and site preparation on changes in the bulk density of ash-influenced forest soils in northern Idaho. Three different levels of surface organic matter were studied. Soil samples were taken before and after harvesting to determine the extent and depth of compaction. Soil bulk densities increased significantly after extensive compaction from site preparation, especially when little logging slash and surface organic matter were left on the soil surface. As site preparation intensity increased, bulk density increased significantly at greater depths in the soil profile. Although ash-influenced soils have naturally low bulk densities, they can easily be compacted to levels that limit growth. The experimental site has been designated as part of the Forest Service's national long-term site productivity study into the impacts of organic matter depletion and soil compaction on stand development.

  6. The Influence of fold and fracture development on reservoir behavior of the Lisburne Group of northern Alaska

    SciTech Connect

    Wesley K. Wallace; Catherine L. Hanks; Jerry Jensen: Michael T. Whalen; Paul Atkinson; Joseph Brinton; Thang Bui; Margarete Jadamec; Alexandre Karpov; John Lorenz; Michelle M. McGee; T.M. Parris; Ryan Shackleton

    2004-07-01

    The Carboniferous Lisburne Group is a major carbonate reservoir unit in northern Alaska. The Lisburne is folded and thrust faulted where it is exposed throughout the Brooks Range, but is relatively undeformed in areas of current production in the subsurface of the North Slope. The objectives of this study were to develop a better understanding of four major aspects of the Lisburne: (1) The geometry and kinematics of folds and their truncation by thrust faults. (2) The influence of folding on fracture patterns. (3) The influence of deformation on fluid flow. (4) Lithostratigraphy and its influence on folding, faulting, fracturing, and reservoir characteristics. Symmetrical detachment folds characterize the Lisburne in the northeastern Brooks Range. In contrast, Lisburne in the main axis of the Brooks Range is deformed into imbricate thrust sheets with asymmetrical hangingwall anticlines and footwall synclines. The Continental Divide thrust front separates these different structural styles in the Lisburne and also marks the southern boundary of the northeastern Brooks Range. Field studies were conducted for this project during 1999 to 2001 in various locations in the northeastern Brooks Range and in the vicinity of Porcupine Lake, immediately south of the Continental Divide thrust front. Results are summarized below for the four main subject areas of the study.

  7. Impact of winter oceanographic conditions on zooplankton abundance in northern Adriatic with implications on Adriatic anchovy stock prognosis

    NASA Astrophysics Data System (ADS)

    Kraus, Romina; Supić, Nastjenjka; Lučić, Davor; Njire, Jakica

    2015-12-01

    Anchovy, Engraulis encrasicolus (L.), is commercially one of the most important Adriatic small pelagic fish. Despite the prevailing oligotrophication trend in the northern Adriatic (NA), the anchovy catch increased after 2000, coinciding with an increased number of the winter type A occurrences, when Po River waters are favoured to spread across the NA. Namely, winter type A is characterised by conditions resulting with Po River waters spreading across the NA along with salinity decrease. On the contrary, in winters of type B, salinity is high. We hypothesized in previous paper, based on correlation between circulation patterns and phytoplankton with anchovy catch, that excess feeding of anchovy in this winter pre-spawning period (February) can lead to increased amounts of the anchovy eggs two months later and subsequently to the total fish catch of the same year. In this paper, we investigate in more details and based on longer time series the relation between anchovy catch and winter circulation patterns of the NA. Additionally, we studied the association between anchovy catch and zooplankton, as anchovy is predominantly zooplanktivorous. We found that zooplankton abundances in winters of A type enhance and that ciliates play an important role in the NA anchovy food web and enrichment of the region with anchovy. Finally, the results of our investigation might in time represent the basics for a sustainable anchovy management in the Adriatic Sea as they enable the development of prediction models of the anchovy stock.

  8. Analysis of weather condition influencing fire regime in Italy

    NASA Astrophysics Data System (ADS)

    Bacciu, Valentina; Masala, Francesco; Salis, Michele; Sirca, Costantino; Spano, Donatella

    2014-05-01

    Fires have a crucial role within Mediterranean ecosystems, with both negative and positive impacts on all biosphere components and with reverberations on different scales. Fire determines the landscape structure and plant composition, but it is also the cause of enormous economic and ecological damages, beside the loss of human life. In addition, several authors are in agreement suggesting that, during the past decades, changes on fire patterns have occurred, especially in terms of fire-prone areas expansion and fire season lengthening. Climate and weather are two of the main controlling agents, directly and indirectly, of fire regime influencing vegetation productivity, causing water stress, igniting fires through lightning, or modulating fire behavior through wind. On the other hand, these relationships could be not warranted in areas where most ignitions are caused by people (Moreno et al. 2009). Specific analyses of the driving forces of fire regime across countries and scales are thus still required in order to better anticipate fire seasons and also to advance our knowledge of future fire regimes. The objective of this work was to improve our knowledge of the relative effects of several weather variables on forest fires in Italy for the period 1985-2008. Meteorological data were obtained through the MARS (Monitoring Agricultural Resources) database, interpolated at 25x25 km scale. Fire data were provided by the JRC (Join Research Center) and the CFVA (Corpo Forestale e di Vigilanza Ambientale, Sardinia). A hierarchical cluster analysis, based on fire and weather data, allowed the identification of six homogeneous areas in terms of fire occurrence and climate (pyro-climatic areas). Two statistical techniques (linear and non-parametric models) were applied in order to assess if inter-annual variability in weather pattern and fire events had a significant trend. Then, through correlation analysis and multi-linear regression modeling, we investigated the

  9. Mycotoxins: toxicity, carcinogenicity, and the influence of various nutritional conditions*

    PubMed Central

    Newberne, Paul M.

    1974-01-01

    Toxicologic diseases of man and animals, associated with molds growing on foods, have been recognized for centuries. Only in recent years, however, have these mycotoxicoses received the attention of many laboratories and skilled scientists around the world in a broad inter-disciplinary effort. This review covers the literature on mycotoxicoses but centers on those about which most is known, particularly the diseases associated with metabolites elaborated by some strains of Aspergilli, Penicillia, Fusaria, Stachybotrys, and Claviceps. The ubiquitous nature of the aflatoxins, toxic metabolites produced by Aspergillus flavus, make them important to public health, especially since it is now known that certain areas of endemic liver disease coincide with consumption of aflatoxins and, often, malnutrition. The older disease of ergotism, the scourge of Europe for centuries, is considered in detail. Alimentary toxic aleukia, which has caused enormous suffering in Russian human and animal populations, is better understood as a result of relatively recent experimental investigations. Stachybotryotoxicosis, a disease previously considered to be of significance only to man has now been identified in domestic animals. Finally, Japanese studies have clearly revealed the hepatotoxicity of certain metabolites of Penicillium molds. Factors that influence susceptibility to mycotoxins and the hazards they present to man are also reviewed. ImagesFIGURE 2. PMID:4620330

  10. Methods and background characteristics of the TOHNN study: a population-based study of oral health conditions in northern Norway

    PubMed Central

    Holde, Gro Eirin; Oscarson, Nils; Tillberg, Anders; Marstrander, Peter; Jönsson, Birgitta

    2016-01-01

    Objectives The aim of the Tromstannen – Oral Health in Northern Norway (TOHNN) study was to investigate oral health and dental-related diseases in an adult population. This article provides an overview of the background of the study and a description of the sample characteristics and methods employed in data collection. Study design Cross-sectional population-based study including a questionnaire and clinical dental examination. Methods A randomly selected sample of 2,909 individuals (20–79 years old) drawn from the population register was invited to participate in the study. The data were collected between October 2013 and November 2014 in Troms County in northern Norway. The questionnaire focused on oral health-related behaviours and attitudes, oral health-related quality of life, sense of coherence, dental anxiety and symptoms from the temporomandibular joint. The dental examinations, including radiographs, were conducted by 11 dental teams in 5 dental offices. The examination comprised of registration of dental caries, full mouth periodontal status, temporomandibular disorders, mucosal lesions and height and weight. The participants were grouped by age (20–34, 35–49, 50–64 and 65–79) and ethnicity (Norwegian, Sámi, other European and other world). Results From the original sample of 2,909 individuals, 1,986 (68.3%) people participated, of whom 1,019 (51.3%) were women. The highest attendance rate was among women 20–34 years old (80.3%) and the lowest in the oldest age group of women (55.4%). There was no difference in response rate between rural and urban areas. There was a positive correlation between population size and household gross income (p < 0.001) and education level (p < 0.001). The majority of Sámi resided in smaller municipalities. In larger cities, most participants used private dental health care services, whereas, in rural areas, most participants used the public dental health care service. Conclusion The TOHNN study has the

  11. Comparing Observed Hurricane Conditions Against Potential Future Climate Change Influences

    NASA Astrophysics Data System (ADS)

    Graham, W. D.

    2012-12-01

    Climate Adaptation Science Investigators: (CASI) is to advance and apply NASA's scientific expertise and products to develop climate adaptation strategies that support NASA's overall mission by minimizing risks to each center's operations, physical assets, and personnel. Using Hurricane Katrina observations as a baseline, we use ADCIRC to model surge extent with simple modifications of the storm track. We examine two time now (T0) scenarios of present-day climatological factors: 1) translating the 2005 path 7 km west; and 2) rotating the approach angle from due-north to WNW. Second, we examine two future time scenarios (TX) by infusing climate change conditions, such as sea level rise and increased storm intensity, into a T0 baseline to assess future impacts. The primary goal of this work entails planning and protecting NASA assets and infrastructure. The adjacent communities, state and local emergency managers, gain benefit from this NASA work as data and analysis includes the surrounding geography.

  12. Northern Hemisphere Atmospheric Influence of the Solar Proton Events and Ground Level Enhancement in January 2005

    NASA Technical Reports Server (NTRS)

    Jackman, C. H.; Marsh, D. R.; Vitt, F. M.; Roble, R. G.; Randall, C. E.; Bernath, P. F.; Funke, B.; Lopez-Puertas, M.; Versick, S.; Stiller, G. P.; Tylka, A. J.; Fleming, E. L.

    2011-01-01

    Solar eruptions in early 2005 led substantial barrage of charged particles on the Earth's atmosphere during the January 16-21 period. Proton fluxes were greatly increased during these several days and led to the production ofHO(x)(H, OH, BO2)and NO(x)(N, NO, NO2), which then caused the destruction of ozone. We focus on the Northern polar region, where satellite measurements and simulations with the Whole Atmosphere Community Climate Model (WACCM3) showed large enhancements in mesospheric HO(x) and NO(x) constituents, and associated ozone reductions, due 10 these solar proton events (SPEs). The WACCM3 simulations show enhanced short-lived OH throughout the mesosphere in the 60-82.5degN latitude band due to the SPEs for most days in the Jan.16-2l,2005 period, in reasonable agreement with the Aura Microwave Limb Sounder (MLS) measurements. Mesospheric HO2 is also predicted to be increased by the SPEs, however, the modeled HO2 results are somewhat larger than the MLS measurements. These HO(x) enhancements led to huge predicted and MLS-measured ozone decreases of greater than 40% throughout most of the Northern polar mesosphere during the SPE period. Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) measurements of hydrogen peroxide (H2O2) show increases throughout the stratosphere with highest enhancements of about 60 ppt y in the lowermost mesosphere over the Jan. 16-18, 2005 period due to the solar protons. WACCM3 predictions indicate H2O2 enhancements over the same time period of more than twice that amount. Measurements of nitric acid (HNO3) by both MLS and MIPAS show an increase of about 1 ppbv above background levels in the upper stratosphere during January 16-29, 2005. WACCM3 simulations show only minuscule HNO3 changes in the upper stratosphere during this time period. However due to the small loss rates during winter, polar mesospheric enhancements of NO(x) are computed to be greater than 50 ppbv during the SPE period. Computed NO

  13. Polar Northern Hemisphere Middle Atmospheric Influence due to Energetic Particle Precipitation in January 2005

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.

    2010-01-01

    Solar eruptions and geomagnetic activity led to energetic particle precipitation in early 2005, primarily during the January 16-21 period. Production of OH and destruction of ozone have been documented due to the enhanced energetic solar proton flux in January 2005 [e.g., Verronen et al., Geophys. Res. Lett.,33,L24811,doi:10.1029/2006GL028115, 2006; Seppala et al., Geophys. Res. Lett.,33,L07804, doi:10.1029/2005GL025571,2006]. These solar protons as well as precipitating electrons also led to the production of NO(x) (NO, NO2). Our simulations with the Whole Atmosphere Community Climate Model (WACCM) show that NO(x) is enhanced by 20-50 ppbv in the polar Northern Hemisphere middle mesosphere (approx.60-70 km) by January 18. Both the SCISAT-1 Atmospheric Chemistry Experiment (ACE) NO(x) measurements and Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIP AS) nighttime NO2 observations show large increases during this period, in reasonable agreement with WACCM predictions. Such enhancements are considerable for the mesosphere and led to simulated increases in polar Northern Hemisphere upper stratospheric odd nitrogen (NO(y)) of2-5 ppbv into February 2005. The largest ground level enhancement (GLE) of solar cycle 23 occurred on January 20, 2005 with a neutron monitor increase of about 270 percent [Gopalswamy et al., 29th International Cosmic Ray Conference, Pune,00,101-104,2005]. We found that protons of energies 300 to 20,000 MeV, not normally included in our computations, led to enhanced stratospheric NO(y) of less than 1 percent as a result of this GLE. The atmospheric impact of precipitating middle energy electrons (30-2,500 keV) during the January 16-21, 2005 period is also of interest, and an effort is ongoing to include these in WACCM computations. This presentation will show both short- and longer-term changes due to the January 2005 energetic particle precipitation.

  14. Influence of hydrologic processes on reproduction of the introduced bivalve Potamocorbula amurensis in northern San Francisco Bay, California

    USGS Publications Warehouse

    Parchaso, F.; Thompson, J.K.

    2002-01-01

    Monthly censusing of reproductive condition of the Asian clam Potamocorbula amurensis at four sites in northern San Francisco Bay over a 9-yr period revealed year-to-year differences in local reproductive activity that are associated with patterns of hydrologic variability. Between 1989 and 1992, Northern California experienced a drought, whereas the period between 1993 and 1998 was marked by a mix of wet and dry years. We took advantage of the extreme year-to-year differences to examine reproductive responses to river inflow patterns. Populations of P. amurensis at the upstream sites in Suisun Bay and Carquinez Strait were more reproductively active during wet years than dry years. Conversely, at the downstream site in San Pablo Bay, the population was more reproductively active during dry years than wet years. We suggest that the different reproductive patterns observed reflect the clam's response to different sources of food. During wet years, organic matter from the rivers augments food supplies in Suisun Bay. During dry years, when inflow into the San Francisco Bay Estuary from the rivers is reduced, water transported from the adjacent ocean into the estuary as far as San Pablo Bay provides a supplemental food supply for the local production. The populations take advantage of these spatially distinct food supplies by initiating and maintaining local reproductive activity. We conclude that the ability of P. amurensis to consume and use various types of food to regulate its reproductive activity is part of the reason for its success as an invasive species.

  15. Sample storage conditions significantly influence faecal microbiome profiles

    PubMed Central

    Choo, Jocelyn M; Leong, Lex EX; Rogers, Geraint B

    2015-01-01

    Sequencing-based studies of the human faecal microbiota are increasingly common. Appropriate storage of sample material is essential to avoid the introduction of post-collection bias in microbial community composition. Rapid freezing to −80 °C is commonly considered to be best-practice. However, this is not feasible in many studies, particularly those involving sample collection in participants’ homes. We determined the extent to which a range of stabilisation and storage strategies maintained the composition of faecal microbial community structure relative to freezing to −80 °C. Refrigeration at 4 °C, storage at ambient temperature, and the use of several common preservative buffers (RNAlater, OMNIgene.GUT, Tris-EDTA) were assessed relative to freezing. Following 72 hours of storage, faecal microbial composition was assessed by 16 S rRNA amplicon sequencing. Refrigeration was associated with no significant alteration in faecal microbiota diversity or composition. However, samples stored using other conditions showed substantial divergence compared to −80 °C control samples. Aside from refrigeration, the use of OMNIgene.GUT resulted in the least alteration, while the greatest change was seen in samples stored in Tris-EDTA buffer. The commercially available OMNIgene.GUT kit may provide an important alternative where refrigeration and cold chain transportation is not available. PMID:26572876

  16. Age at menarche: the influence of environmental conditions

    NASA Astrophysics Data System (ADS)

    Saar, E.; Shalev, C.; Dalal, I.; Sod-Moriah, U. A.

    1988-03-01

    Age at menarche was studied by the recollection method in two groups of Causasian Jewish high school girls, inhabitants of two towns in Israel, Safad and Elat. The two towns differ mainly in climatic conditions. The age at menarche was found to be significantly lower ( P<0.02) in the hot town of Elat than in the temperate town of Safad: 13.30±1.21 and 13.58±0.9 years, respectively (mean ±SD). A significant association was found between the age at menarche and the town in which the girls lived. Accordingly, in the hot town of Elat, the percentage of girls who had their first menstrual cycle by the age of 12 years and earlier, was more than double that of the girls in Safad (17.9% and 7.1%, respectively). It is concluded that the environmental temperature, with or without any possible interaction of humidity, is probably responsible for the tendency for an earlier onset of menarche in girls living in the hot town of Elat.

  17. Using supplemental food and its influence on survival of northern bobwhite (Colinus virginianus)

    USGS Publications Warehouse

    Townsend, D.E., II; Lochmiller, R.L.; DeMaso, S.J.; Leslie, David M., Jr.; Peoples, A.D.; Scott, A C.; Parry, E.S.

    2000-01-01

    Biologists have debated the effectiveness of supplemental feeders as a management tool for the northern bobwhite (Colinus virginianus), but few extensive evaluations have been conducted. We examined 783 crops from harvested bobwhites during 1992-1996 to determine effects of climatic stress in winter on use of supplemental feeders and their impact on survival rate in winter. Crops of bobwhites harvested from areas with supplemental feeders contained 28.2% supplemental food compared with 5.5% (P<0.001) for those from areas without supplemental feeders. Winter climate was not a significant predictor of the proportional use of supplemental feeders. Rates of winter survival were greater on areas with supplemental feeders compared with non-supplemented areas in winters 1992-1993 (P=0.001) and 1993-1994 (P=0.002), but in 1994-1995, rates were greater on nonsupplemented areas (P=0.032). Cause-specific mortality rates indicated that supplemental feeders did not predispose bobwhites to hunter harvest or predators. Results suggested that bobwhites can gain nutritional benefits from supplemental feeders during times of severe winter stress.

  18. Geographical, linguistic, and cultural influences on genetic diversity: Y-chromosomal distribution in Northern European populations.

    PubMed

    Zerjal, T; Beckman, L; Beckman, G; Mikelsaar, A V; Krumina, A; Kucinskas, V; Hurles, M E; Tyler-Smith, C

    2001-06-01

    We analyzed 10 Y-chromosomal binary markers in 363 males from 8 populations in Northern Europe and 5 Y microsatellites in 346 of these individuals. These populations can be grouped according to cultural, linguistic, or geographical criteria, and the groupings are different in each case. We can therefore ask which criterion best corresponds to the distribution of genetic variation. In an AMOVA analysis using the binary markers, 13% of the Y variation was found between populations, indicating a high level of differentiation within this small area. No significant difference was seen between the traditionally nomadic Saami and the neighboring, historically farming, populations. When the populations were divided into Uralic speakers and Indo-European speakers, 8% of the variation was found between groups, but when they were divided according to geographical location, 14% of the variation was between groups. Geographical factors have thus been the most important in limiting gene flow between these populations, but linguistic differences have also been important in the east. PMID:11371596

  19. Evolution of a karst polje influenced by glaciation: The Gomance piedmont polje (northern Dinaric Alps)

    NASA Astrophysics Data System (ADS)

    Žebre, Manja; Stepišnik, Uroš; Colucci, Renato R.; Forte, Emanuele; Monegato, Giovanni

    2016-03-01

    Gomance is a piedmont karst polje in the northern Dinaric Alps presenting geomorphological and sedimentological evidence of past glaciation. During the Pleistocene the polje was situated at the edge of the Snežnik and Gorski Kotar ice fields from where two outlet glaciers reached Gomance. The morphogenesis of the polje was reconstructed by means of geomorphological mapping, sedimentological studies, and ground penetrating radar (GPR) measurements, supported by hand-drillings. With GPR an almost entirely buried moraine system was also imaged and mapped, crucial in reconstructing the polje history. The depression was karstified and well drained without any surface streams before the Last Glaciation. When the glacier front reached the depression, the entire floor became covered by glacial and outwash deposits. Surface runoff dominated over karst drainage in a large part of the polje, particularly where distal outwash deposits with low effective porosity functioned as an aquitard. These deposits diverted surface drainage toward the lowest edge of the polje, which functioned as a ponor front along the entire length. The outwash system of the Gomance polje was active during the Last Glaciation as suggested by radiocarbon-dated outwash deposits.

  20. Does predation risk influence habitat use by northern redbelly dace Phoxinus eos at different spatial scales?

    PubMed

    Dupuch, A; Magnan, P; Bertolo, A; Dill, L M; Proulx, M

    2009-05-01

    This study investigated the relationship between spatial variations in predation risk and abundance of northern redbelly dace Phoxinus eos at both macroscale (littoral v. pelagic zones) and microscale (structured v. open water habitats in the littoral zone) of Canadian Shield lakes. Minnow traps were placed in both structured and open water habitats in the littoral zone of 13 Canadian Shield lakes, and estimates of the relative predation risk of P. eos in both the pelagic and the littoral zones were obtained from tethering experiments. Results showed that (1) the mean abundance of P. eos in the littoral zone was positively correlated with the relative predation risk in the pelagic zone, (2) P. eos preferentially used structured over open water habitats in the littoral zone and (3) this preference was not related to the relative predation risk in the littoral zone but decreased as the relative predation risk increased in the pelagic zone. At the lake level, these results support the hypothesis that P. eos enter the littoral zone to avoid pelagic piscivores. At the littoral zone level, the results do not necessarily contradict the widely accepted view that P. eos preferentially use structured over open habitats to reduce their predation risk, but suggest that flexibility in antipredator tactics (e.g. shelter use v. shoaling) could explain the spatial distribution of P. eos between structured and open water habitats. PMID:20735640

  1. Barred owls and landscape attributes influence territory occupancy of northern spotted owls

    PubMed Central

    Sovern, Stan G; Forsman, Eric D; Olson, Gail S; Biswell, Brian L; Taylor, Margaret; Anthony, Robert G

    2014-01-01

    We used multi-season occupancy analyses to model 2 fates of northern spotted owl territories in relation to habitat amount, habitat fragmentation, and the presence of barred owls in Washington State, USA, 1989–2005. Local colonization is the probability a territory unoccupied by a spotted owl in year i would be occupied in year i + 1, and local extinction is the probability a territory that was occupied by a spotted owl in year i would be unoccupied in year i + 1. We found a negative relationship between local extinction probability and amount of late-seral forest edge. We found a negative relationship between colonization probability and the number of late-seral forest patches (higher fragmentation), and a negative relationship between colonization probability and the amount of non-habitat within 600 m of a spotted owl territory center (Akaike weight = 0.59). The presence of barred owls was positively related to extinction probability and negatively related to detection probability of spotted owls. The negative relationship between presence of barred owls and detectability of spotted owls indicated that spotted owls could be modifying their calling behavior in the presence of barred owls. The positive relationship between barred owl detections and local extinction probability suggests that because of competition with barred owls, spotted owls are being displaced. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. PMID:25558093

  2. Influence of variations in extratropical wintertime teleconnections on Northern Hemisphere temperature

    SciTech Connect

    Hurrell, J.W.

    1996-03-15

    Pronounced changes in the wintertime atmospheric circulation have occurred since the mid-1970s over the ocean basins of the Northern Hemisphere, and these changes have had a profound effect on surface temperatures. The variations over the North Atlantic are related to changes in the North Atlantic Oscillation (NAO), while the changes over the North Pacific are linked to the tropics and involve variations in the Aleutian low with teleconnections downstream over North America. Multivariate linear regression is used to show that nearly all of the cooling in the northwest Atlantic and the warming across Europe and downstream over Eurasia since the mid-1970s results from the changes in the NAO, and the NAO accounts for 31% of the hemispheric interannual variance over the past 60 winters. Over the Pacific basin and North America, the temperature anomalies result in part from tropical forcing associated with the El Nino-Southern Oscillation phenomenon but with important feedbacks in the extratropics. The changes in circulation over the past two decades have resulted in a surface temperature anomaly pattern of warmth over the continents and coolness over the oceans. This pattern of temperature change has amplified the observed hemispheric-averaged warming because of it interaction with land and ocean; temperature changes are larger over land compared to the oceans because of the small heat capacity of the former. 13 refs., 5 fig., 2 tab.

  3. Climate Change across the United States Northern Great Plains Influencing the Snowpack and the Energy Balance

    NASA Astrophysics Data System (ADS)

    Fassnacht, S. R.; Cherry, M. L.

    2014-12-01

    On average, global temperatures have warmed at a greater rate in the past 50 years than in any preceding period. A warmer climate has been shown to yield less snowfall, a shallower snowpack and an earlier onset of snowmelt. Several studies have examined changes to the ratio of snow to rain throughout the United States, and found that there has not been a change in the amount of precipitation but at many locations there has been a decrease in the amount of snowfall. Across the Northern Great Plains of the central United States, snow accumulation is shallow but persistent for most of the winter. Here, 20 meteorological stations are used to examined climate change across this region over the past 60 years. In general, the amounts of precipitation (and snowfall) are not changing, but the number of days with snow has been decreasing, as the annual maximum and minimum temperatures have been warming. However, there is substantial spatial variability in the trends across this region. Since winter precipitation in solid phase will add fresh snow to the pack and increase its albedo, which alters the energy balance at the surface, albedo is modeled for all stations. Two adjacent stations are explored in further detail to highlight opposite trends.

  4. Seasonal weather influences on yearling beef steer production in C3-dominated Northern Great Plains rangeland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the face of an increasingly variable climate, long-term cattle weight gain datasets are rare, yet invaluable, for determining site-specific influences of seasonal weather patterns on cattle production. Here, we present a long-term (1936 – 2005) yearling Hereford steer data set collected at the No...

  5. Influence of Management on Soil Organic Carbon Dynamics in Northern Mixed-Grass Rangeland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grazing rangelands can influence plant community structure, soil chemical and physical properties, and the distribution and cycling of nutrients within the plant-soil system. Studies initiated in 1982 at the High Plains Grasslands Research Station near Cheyenne, Wyoming, have shown that after 12 yea...

  6. Seasonal weather influences on yearling steer beef production in C3-dominated Northern Great Plains rangeland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the face of an increasingly variable climate, long-term cattle weight gain datasets are rare, yet invaluable, for determining site-specific influences of seasonal weather patterns on cattle production. Here, we present a long-term (1936 – 2005) yearling Hereford steer data set collected at the No...

  7. Assessment of the potential for hydro-solidarity within plural legal conditions of traditional irrigation systems in northern Tanzania

    NASA Astrophysics Data System (ADS)

    Kemerink, J. S.; Ahlers, R.; van der Zaag, P.

    Competition over water resources and related disputes over water are inherently local and context-specific in their manifestations. In Makanya catchment, located in the mid-reaches of the Pangani river basin in northern Tanzania, competition over water is apparent and with increased demands for water disputes are likely to become fiercer in the near future. Negotiations between upstream and downstream users at various levels in the catchment have resulted in water sharing arrangements or are still on-going while other negotiations seem to be stranded in impasses. Why in certain situations water sharing among users evolves, while in other cases mutual agreements can not be reached, is not yet well understood. Insight in the plural legal context in which water sharing arrangement among water users develop could set light on complex resource use and management realities as well as the ability of various water users to influence the negotiations over water. The hydro-solidarity concept is referred to as potential mechanism to reconcile conflicts over water. Hydro-solidarity promotes ethical dimensions as integral part of decision making and is assumed to be based on a universal set of commonly accepted norms and rules. Through analysis of the plural legal context in which water sharing arrangements among the smallholder farmers in the Makanya catchment develop, the paper explores the existence of ethical dimensions in decision making and their legitimacy. In this way the potential of the hydro-solidarity concept as mechanism to reconcile conflicts over water can be assessed in the context-specific plural reality. The paper concludes that, although ethical dimensions in decision making in the Makanya catchment exist, the hydro-solidarity concept as mechanism to reconcile disputes over water has limited potential as long as it does not embrace the plural reality. The authors argue that, instead of searching for a universal normative order, legal plural analysis can serve

  8. Influence of meteorological conditions on RSV infection in Portugal

    NASA Astrophysics Data System (ADS)

    Oliveira-Santos, M.; Santos, J. A.; Soares, J.; Dias, A.; Quaresma, M.

    2016-04-01

    Acute viral bronchiolitis is a common cause for infant hospital admissions. Of all etiological agents, respiratory syncytial virus (RSV) is commonly the most frequent. The present study assesses relationships between atmospheric factors and RSV infections in under 3-year-old patients admitted to the Inpatient Paediatric Service of Vila Real (North of Portugal). For this purpose, (1) clinical files of children admitted with a diagnosis of acute bronchiolitis from September 2005 to December 2015 (>10 years) were scrutinised and (2) local daily temperature/precipitation series, as well as six weather types controlling meteorological conditions in Portugal, were used. Fifty-five percent of all 770 admitted children were effectively infected with a given virus, whilst 48 % (367) were RSV+, i.e. 87 % of virus-infected children were RSV+. The bulk of incidence is verified in the first year of age (82 %, 302), slightly higher in males. RSV outbreaks are typically from December to March, but important inter-annual variability is found in both magnitude and shape. Although no clear connections were found between monthly temperatures/precipitation and RSV outbreaks apart from seasonality, a linkage to wintertime cold spells is apparent on a daily basis. Anomalously low minimum temperatures from the day of admittance back to 10 days before are observed. This relationship is supported by anomalously high occurrences of the E and AA weather types over the same period, which usually trigger dry and cold weather. These findings highlight some predictability in the RSV occurrences, revealing potential for modelling and risk assessments.

  9. The influence of convection parameterisations under alternate climate conditions

    NASA Astrophysics Data System (ADS)

    Rybka, Harald; Tost, Holger

    2013-04-01

    In the last decades several convection parameterisations have been developed to consider the impact of small-scale unresolved processes in Earth System Models associated with convective clouds. Global model simulations, which have been performed under current climate conditions with different convection schemes, significantly differ among each other in the simulated precipitation patterns due to the parameterisation assumptions and formulations, e.g. the simplified treatment of the cloud microphysics. Additionally, the simulated transport of short-lived trace gases strongly depends on the chosen convection parameterisation due to the differences in the vertical redistribution of mass. Furthermore, other meteorological parameters like the temperature or the specific humidity show substantial differences in convectively active regions. This study presents uncertainties of climate change scenarios caused by different convection parameterisations. For this analysis two experiments (reference simulation with a CO2 concentration of 348 ppm; 2xCO2-simulation with a CO2 concentration of 696 ppm) are calculated with the ECHAM/MESSy atmospheric chemistry (EMAC) model applying four different convection schemes (Tiedtke, ECMWF, Emanuel and Zhang-McFarlane - Hack) and two resolutions (T42 and T63), respectively. The results indicate that the equilibrium climate sensitivity is independent of the chosen convection parameterisation. However, the regional temperature increase, induced by a doubling of the carbon dioxide concentration, demonstrates differences of up to a few Kelvin at the surface as well as in the UTLS for the ITCZ region depending on the selected convection parameterisation. The interaction between cloud and convection parameterisations results in a large disagreement of precipitation patterns. Although every 2xCO2 -experiment simulates an increase in global mean precipitation rates, the change of regional precipitation patterns differ widely. Finally, analysing

  10. Detecting the influence of secondary environmental gradients on chironomid-inferred paleotemperature reconstructions in northern North America

    NASA Astrophysics Data System (ADS)

    Medeiros, A. S.; Gajewski, K.; Porinchu, D. F.; Vermaire, J. C.; Wolfe, B. B.

    2015-09-01

    We examine the influence of multiple environmental factors on quantitative reconstructions of past climate that are based on conventional transfer function approaches using subfossil midge remains preserved in lake sediments. Chironomid assemblages from the uppermost sediments of 366 lakes spanning northern North America were compared to environmental parameters using direct gradient analysis. While temperature expectedly explained the largest amount of variation in the chironomid assemblages, dissolved organic carbon (DOC) and total Kjeldahl nitrogen (TKN) accounted for significant amounts of the remaining variance. By constraining chironomid assemblages to mean-July air temperature (JulyT), we found a cluster of 70 lakes that were orthogonal to the primary temperature gradient in ordination. These lakes tended to be cold with higher DOC and TKN concentrations, yet had chironomid assemblages that were similar to the assemblages found in less productive, warmer lakes. In order to examine how secondary gradients affected paleotemperature reconstructions, three chironomid-based transfer function models were generated: a full dataset model (all 366 lakes), a reduced temperature-constrained model (296 lakes), and a reduced secondary-constrained model (70 lakes). Application of these models to four previously published Holocene paleotemperature reconstructions were used to distinguish the influence of temperature versus secondary-gradient effects. While unproductive Arctic lake paleotemperature reconstructions were found to be robust, reconstructions for two lakes in the boreal-tundra ecotone suggest secondary gradients influenced parts of their records. We recommend that passive core trajectory analysis upon our expansive surface-sediment calibration set provides a means to assess the veracity of paleotemperature reconstructions and potential influence of secondary gradients.

  11. DISTRIBUTION AND COMPOSITION OF DISSOLVED AND PARTICULATE ORGANIC CARBON IN NORTHERN SAN FRANCISCO BAY DURING LOW FRESHWATER FLOW CONDITIONS

    EPA Science Inventory

    The distribution of organic matter was studied in northern San Francisco Bay monthly through spring and summer 1996 along the salinity gradient from the Sacramento River to Central Bay. Dissolved constituents included monosaccharides (MONO), total carbohydrates (TCHO), dissolved ...

  12. Chemical Evolution of Groundwater Near a Sinkhole Lake, Northern Florida: 1. Flow Patterns, Age of Groundwater, and Influence of Lake Water Leakage

    NASA Astrophysics Data System (ADS)

    Katz, Brian G.; Lee, Terrie M.; Plummer, L. Niel; Busenberg, Eurybiades

    1995-06-01

    Leakage from sinkhole lakes significantly influences recharge to the Upper Floridan aquifer in poorly confined sediments in northern Florida. Environmental isotopes (oxygen 18, deuterium, and tritium), chlorofluorocarbons (CFCs: CFC-11, CCl3F; CFC-12, CCl2F2; and CFC-113, C2Cl3F3), and solute tracers were used to investigate groundwater flow patterns near Lake Barco, a seepage lake in a mantled karst setting in northern Florida. Stable isotope data indicated that the groundwater downgradient from the lake contained 11-67% lake water leakage, with a limit of detection of lake water in groundwater of 4.3%. The mixing fractions of lake water leakage, which passed through organic-rich sediments in the lake bottom, were directly proportional to the observed methane concentrations and increased with depth in the groundwater flow system. In aerobic groundwater upgradient from Lake Barco, CFC-modeled recharge dates ranged from 1987 near the water table to the mid 1970s for water collected at a depth of 30 m below the water table. CFC-modeled recharge dates (based on CFC-12) for anaerobic groundwater downgradient from the lake ranged from the late 1950s to the mid 1970s and were consistent with tritium data. CFC-modeled recharge dates based on CFC-11 indicated preferential microbial degradation in anoxic waters. Vertical hydraulic conductivities, calculated using CFC-12 modeled recharge dates and Darcy's law, were 0.17, 0.033, and 0.019 m/d for the surficial aquifer, intermediate confining unit, and lake sediments, respectively. These conductivities agreed closely with those used in the calibration of a three-dimensional groundwater flow model for transient and steady state flow conditions.

  13. How do climate and human impact affect Sphagnum peatlands under oceanic-continental climatic conditions? 2000 years of fire and hydrological history of a bog in Northern Poland

    NASA Astrophysics Data System (ADS)

    Marcisz, Katarzyna; Tinner, Willy; Colombaroli, Daniele; Kołaczek, Piotr; Słowiński, Michał; Fiałkiewicz-Kozieł, Barbara; Lamentowicz, Mariusz

    2014-05-01

    Climate change affects many natural processes and the same applies to human impact For instance climate change and anthropogenic activities may cause increased fire activity or change peatland dynamics. Currently it is still unknown how Sphagnum peatlands in the oceanic-continental transition zone of Poland may respond to combined effects of heat waves, drought and fire. The aim of the study was to reconstruct the last 2000 years palaeohydrology and fire history at Linje bog in Northern Poland. The main task was to determine the drivers of fire episodes, particularly to identify climatic and anthropogenic forcing. A two-meter peat core was extracted and subsampled with a high resolution. Micro- and macroscopic charcoal analyses were applied to determine past fire activity and the results compared with palaeohydrological reconstructions based on testate amoeba analysis. Palynological human indicators were used to reconstruct human activity. A depth-age model including 20 14C dates was constructed to calculate peat accumulation rates and charcoal influx. We hypothesised that: 1) fire frequency in Northern Poland was determined by climatic conditions (combination of low precipitation and heat waves), as reflected in peatland water table, and that 2) past fire episodes in the last millennium were intensified by human activity. Furthermore climate may have influenced human activity over harvest success and the carrying capacity. Our study shows that fire was important for the studied ecosystem, however, its frequency has increased in the last millennium in concomitance with land use activities. Landscape humanization and vegetation opening were followed by a peatland drying during the Little Ice Age (from ca. AD 1380). Similarly to other palaeoecological studies from Poland, Linje peatland possessed an unstable hydrology during the Little Ice Age. Increased fire episodes appeared shortly before the Little Ice Age and most severe fires were present in the time when

  14. Aerosols and their influence on radiation partitioning and savanna productivity in northern Australia

    SciTech Connect

    Kanniah, K. D.; Beringer, J.; Tapper, N. J.; Long, Charles N.

    2010-05-01

    We investigated the effect of aerosols and clouds on the Net Ecosystem Productivity (NEP) of savannas in northern Australia using aerosol optical depth, clouds and radiation data from the Atmospheric Radiation Measurement (ARM) site in Darwin and carbon flux data measured from eddy covariance techniques from a site at Howard Springs, 35km southeast of Darwin. Generally we found that the concentration of aerosols in this region was relatively low than observed at other sites, therefore the proportion of diffuse radiation reaching the earths surface was only ~ 30%. As a result, we observed only a modest change in carbon uptake under aerosol laden skies and there was no significant difference for dry season Radiation Use Efficiency (RUE) between clear sky, aerosols or thin clouds. On the other hand thick clouds in the wet season produce much more diffuse radiation than aerosols or thin clouds and therefore the initial canopy quantum efficiency was seen to increase 45 and 2.5 times more than under thin clouds and aerosols respectively. The normalized carbon uptake under thick clouds is 57% and 50% higher than under aerosols and thin clouds respectively even though the total irradiance received under thick clouds was reduced 59% and 50% than under aerosols and thin clouds respectively. However, reduction in total irradiance decreases the mean absolute carbon uptake as much as 22% under heavy cloud cover compared to thin clouds or aerosols. Thus, any increase in aerosol concentration or cloud cover that can enhance the diffuse component may have large impacts on productivity in this region.

  15. Influence of mowing on dynamics of native phytoseiid mites and Tetranychus urticae in apple orchards in northern Japan.

    PubMed

    Funayama, Ken

    2016-09-01

    To support practical integrated pest management in commercial apple orchards, I investigated the influence of mowing on the occurrence of Tetranychus urticae and native phytoseiid mites in apple orchards sprayed with selective insecticides in Akita Prefecture, northern Japan, from 2013 to 2015. The orchards were not mown in 2013, and unmown and mown plots were compared in 2014 and 2015. There were significantly fewer Typhlodromus vulgaris on apple leaves and Amblyseius tsugawai in the undergrowth in mown plots than in unmown plots in both years. Conversely, there were significantly more T. urticae on leaves and undergrowth in mown plots than in unmown plots. The reason for the decreased populations of these phytoseiid mites may be a lack of food (pollen) needed for reproduction on apple trees and in the undergrowth due to mowing. These results indicate that mowing strongly influences generalist phytoseiid mites in apple orchards. Moreover, mowing might increase the density of T. urticae in apple trees because increased nitrogen in the leaves increases fecundity; in addition, drought might promote the increase of mite numbers. Thus, retention of undergrowth suppresses T. urticae in apple orchards. PMID:27380500

  16. Influence of climatic and hydrological factors on structure and composition of peat from northern wetland territories with low anthropogenic impact.

    PubMed

    Parfenova, L N; Selyanina, S B; Trufanova, M V; Bogolitsyn, K G; Orlov, A S; Volkova, N N; Ponomareva, T I; Sokolova, T V

    2016-05-01

    Northern wetlands ecosystems play an important role in the hydrological balance of neighboring areas, where they act as chemical barriers against anthropogenic and technogenic contaminations. Studied region is well known for quantity of peat deposits and the volume of peat resources. Peat can be considered as a highly informative marker for assessing change in environmental conditions. The study presents the results of the first investigation of peat samples, collected from representative ecosystems of northern wetland territories with low anthropogenic impact. Component and element composition of various peat types were studied in a relation to hydrologic, climate and sampling conditions. It was found out that organic and ash contents are more dependent on the type of the bog, than geographic location. Climatic factors are more important for the formation of bitumen. The degradation degree in peat increases proportionally to content of humates. High content of biogenic and lithogenic elements was observed in transition- and low-moor peat. The content of trace elements in peat samples do not depend on the type of the peat. The structural properties of peat were studied by the light microscopy, AFM and dynamic light scattering. It was determined that the conformation of studied peat samples is characterized by elements of asymmetry. The observed particles in the solutions exist in dynamic equilibrium with separated globular macromolecules. The size of these nanoparticles is comparable with the size of the particles of other biopolymers of similar nature. Swelling of peat in liquid water was studied. The relationship between structural specificities, origin of peat and its maximum degree of swelling was found. The degree of swelling can be used as structural-sensitive parameter in further research. PMID:26874767

  17. Non-polar organic compounds in marine aerosols over the northern South China Sea: Influence of continental outflow.

    PubMed

    Zhao, Yan; Zhang, Yingyi; Fu, Pingqing; Ho, Steven Sai Hang; Ho, Kin Fai; Liu, Fobang; Zou, Shichun; Wang, Shan; Lai, Senchao

    2016-06-01

    Filter samples of total suspended particle (TSP) collected during a cruise campaign over the northern South China Sea (SCS) from September to October 2013 were analyzed for non-polar organic compounds (NPOCs) as well as organic carbon (OC), elemental carbon (EC) and water-soluble ions. A total of 115 NPOCs species in groups of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), iso-/antiso-alkanes, hopanes, steranes, methylalkanes, branched alkanes, cycloalkanes, alkenes and phthalates were detected. The characteristics of NPOCs in marine TSP samples were investigated to understand the sources from the Asian continent and other regions. The concentrations of total NPOCs ranged from 19.8 to 288.2 ng/m(3) with an average of 87.9 ng/m(3), which accounted for 0.8-1.7% (average 1.0%) of organic matter (OM). n-Alkanes was the predominant group, accounting for 43.1-79.5%, followed by PAHs (5.5-44.4%) and hopanes (1.6-11.4%). We found that primary combustion (biomass burning/fossil fuel combustion) was the dominant source for the majority of NPOCs (89.1%). Biomass burning in southern/southeastern China via long-range transport was proposed to be a major contributor of NPOCs in marine aerosols over the northern SCS, suggested by the significant correlations between nss-K(+) and NPOCs groups as well as the analysis of air mass back-trajectory and fire spots. For the samples with strong continental influence, the strong enhancement in concentrations of n-alkanes, PAHs, hopanes and steranes were attributed to fossil fuel (coal/petroleum) combustion. In addition, terrestrial plants waxes were another contributor to NPOCs. PMID:27023121

  18. Reconstructing conditions during dolomite formation on a Carnian coastal sabkha/alluvial plain using 87Sr/86Sr isotopes - Travenanzes Formation, northern Italy

    NASA Astrophysics Data System (ADS)

    Rieder, Maximilian; Wegner, Wencke; Horschinegg, Monika; Preto, Nereo; Breda, Anna; Klötzli, Urs; Peckmann, Jörn; Meister, Patrick

    2016-04-01

    indicated by oxygen isotopes. The marine 87Sr/86Sr values have been reconstructed for most of the Phanerozoic and are nearly constant in the Carnian (McArthur et al., 2012), while the age of the dolomite beds of the Travenanzes Formation is constrained by their stratigraphic position in the measured section (Dibona Section; Preto et al., 2015). The continental Sr isotope signal is governed by weathering rates, especially during silicate weathering of the source rock in the catchment area (McArthur et al., 2012). Through 87Sr/86Sr isotope investigation of primary dolomite in beds and nodules of the coastal sabkha or alluvial plain environment, the influence of marine or continental conditions can be determined. The finding of celestine SrSO4 and Sr-rich barite BaSO4 within the cemented dolomite by SEM indicates enrichment of Sr, possibly during strong evaporative conditions. Hence, the generation of phase-specific Sr-isotope data will allow for a more precise reconstruction of the conditions that led to dolomite formation in the Triassic shallow coastal sabkha/alluvial plain environment. McArthur et al. (2012) Strontium isotope stratigraphy. In: "The geologic time scale" (F.M Gradstein et al., eds.), Elsevier, p. 127-144. Preto et al. (2015) Primary dolomite in the Late Triassic Travenanzes Formation Dolomites, Northern Italy: Facies control and possible bacterial influence. Sedimentology 62, p. 697-716.

  19. Influence of vegetation canopies on precipitation partitioning and isotope fractionation in northern upland catchments

    NASA Astrophysics Data System (ADS)

    Braun, Hannah; Tetzlaff, Doerthe; Soulsby, Chris; Weiler, Markus

    2016-04-01

    Climate change is predicted to have far reaching implications for northern high latitude regions including changing precipitation regimes and increasing temperatures in the coming decades. In many areas this will promote increased forest cover as a result of vegetation succession or mitigation measures. For example, in the Scottish Highlands, forest cover is increasing as a result of adaptive management and increased biofuel production. In the wet, windy Scottish hydroclimate this has the potential to significantly increase interception losses, reduce net precipitation and affect the spatial and temporal distribution of soil moisture. Recent studies have also shown that such processes may also change the isotopic signature of net rainfall in throughfall and stemflow with implications for using isotopes as hydrological tracers. Such effects may be exacerbated by projected higher temperatures and reduced summer precipitation. The main focus of this study was to quantify the effects of forest and non-forest vegetation canopies on the spatio-temporal variability of throughfall and stemflow in the Bruntland Burn, a 3.2 km2 montane experimental catchment in the Scottish Highlands. We investigated differences in both the quantity and isotopic composition of throughfall and stemflow under Scots Pine (Pinus sylvestris) forest and heather (Calluna vulgaris) moorland growing on podzolic soils. Altogether, 75 throughfall and 10 stemflow collectors were placed in four plots with different topographic positions and vegetation characteristics (two different aged Scots pine plantations and two heather sites) and canopy coverage was determined using digital photography. Over a 5 month sampling period, weekly throughfall samples were taken. We also analysed more than 1100 samples for stable isotopes δ18O and δD. Interception losses were 38% under moorland and up to 47% for the plantation sides. Both throughfall and stemflow amounts were found to be highly variable and were mostly

  20. How to comprehensively evaluate river corridor conditions? A comparison of different biotic and morphological indices in northern Italy

    NASA Astrophysics Data System (ADS)

    Golfieri, Bruno; Surian, Nicola; Hardersen, Sönke; Maiolini, Bruno

    2016-04-01

    The assessment of river conditions is crucial for planning appropriate management actions. The European Water Framework Directive 2000/60/EC (WFD) requires the assessment of biological, physical-chemical and hydromorphological elements to define the ecological status of rivers. The WFD suggests the use of different bioindicators (i.e. benthic macroinvertebrates, diatoms, aquatic macrophytes and fish), the so called "biological quality elements" (BQEs). However, recent studies showed that BQEs-based indices have two main limitations: (i) their standard application is limited to flowing channels and (ii) they are not sensitive to hydromorphological alteration. Hydromorphological conditions are usually evaluated applying methods for physical habitat assessment (i.e. the River Habitat Survey or derived methods) that consist in site-scale inventories of river forms and anthropic structures. The lack of consideration of wider spatial (i.e. reach or catchment scale) and temporal scales (e.g. channel evolution over the last 50-100 years) make such methods inadequate for a sound diagnosis of morphological alterations. The Morphological Quality Index (MQI) and the dragonfly-based Odonate River Index (ORI) were developed in the recent years to overcome the above-mentioned limitations and to assess the condition of the whole river corridor (i.e. the channel and its adjacent floodplain) at reach scale. In this study we correlated the assessments of MQI, ORI and two BQEs-based biotic indices (i.e. STAR_ICMi for benthic macroinvertebrates and ICMi for diatoms) in 15 lowland river reaches in northern Italy. The selected reaches are characterized by a wide range of morphological degradation. MQI and ORI were highly correlated, probably because both methods work at reach scale and consider the integrity of the whole river corridor, either in terms of morphology or considering ecological aspects. In contrast, no significant relationships were found between MQI and ORI and the BQEs

  1. Pollution influences on atmospheric composition and chemistry at high northern latitudes: Boreal and California forest fire emissions

    NASA Astrophysics Data System (ADS)

    Singh, H. B.; Anderson, B. E.; Brune, W. H.; Cai, C.; Cohen, R. C.; Crawford, J. H.; Cubison, M. J.; Czech, E. P.; Emmons, L.; Fuelberg, H. E.; Huey, G.; Jacob, D. J.; Jimenez, J. L.; Kaduwela, A.; Kondo, Y.; Mao, J.; Olson, J. R.; Sachse, G. W.; Vay, S. A.; Weinheimer, A.; Wennberg, P. O.; Wisthaler, A.; The Arctas Science Team

    2010-11-01

    We analyze detailed atmospheric gas/aerosol composition data acquired during the 2008 NASA ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) airborne campaign performed at high northern latitudes in spring (ARCTAS-A) and summer (ARCTAS-B) and in California in summer (ARCTAS-CARB). Biomass burning influences were widespread throughout the ARCTAS campaign. MODIS data from 2000 to 2009 indicated that 2008 had the second largest fire counts over Siberia and a more normal Canadian boreal forest fire season. Near surface arctic air in spring contained strong anthropogenic signatures indicated by high sulfate. In both spring and summer most of the pollution plumes transported to the Arctic region were from Europe and Asia and were present in the mid to upper troposphere and contained a mix of forest fire and urban influences. The gas/aerosol composition of the high latitude troposphere was strongly perturbed at all altitudes in both spring and summer. The reactive nitrogen budget was balanced with PAN as the dominant component. Mean ozone concentrations in the high latitude troposphere were only minimally perturbed (<5 ppb), although many individual pollution plumes sampled in the mid to upper troposphere, and mixed with urban influences, contained elevated ozone (ΔO 3/ΔCO = 0.11 ± 0.09 v/v). Emission and optical characteristics of boreal and California wild fires were quantified and found to be broadly comparable. Greenhouse gas emission estimates derived from ARCTAS-CARB data for the South Coast Air Basin of California show good agreement with state inventories for CO 2 and N 2O but indicate substantially larger emissions of CH 4. Simulations by multiple models of transport and chemistry were found to be broadly consistent with observations with a tendency towards under prediction at high latitudes.

  2. Environmental Attributes Influencing the Distribution of Burkholderia pseudomallei in Northern Australia

    PubMed Central

    Baker, Anthony L.; Ezzahir, Jessica; Gardiner, Christopher; Shipton, Warren; Warner, Jeffrey M.

    2015-01-01

    Factors responsible for the spatial and temporal clustering of Burkholderia pseudomallei in the environment remain to be elucidated. Whilst laboratory based experiments have been performed to analyse survival of the organism in various soil types, such approaches are strongly influenced by alterations to the soil micro ecology during soil sanitisation and translocation. During the monsoonal season in Townsville, Australia, B. pseudomallei is discharged from Castle Hill (an area with a very high soil prevalence of the organism) by groundwater seeps and is washed through a nearby area where intensive sampling in the dry season has been unable to detect the organism. We undertook environmental sampling and soil and plant characterisation in both areas to ascertain physiochemical and macro-floral differences between the two sites that may affect the prevalence of B. pseudomallei. In contrast to previous studies, the presence of B. pseudomallei was correlated with a low gravimetric water content and low nutrient availability (nitrogen and sulphur) and higher exchangeable potassium in soils favouring recovery. Relatively low levels of copper, iron and zinc favoured survival. The prevalence of the organism was found to be highest under the grasses Aristida sp. and Heteropogon contortus and to a lesser extent under Melinis repens. The findings of this study indicate that a greater variety of factors influence the endemicity of melioidosis than has previously been reported, and suggest that biogeographical boundaries to the organisms’ distribution involve complex interactions. PMID:26398904

  3. Environmental Attributes Influencing the Distribution of Burkholderia pseudomallei in Northern Australia.

    PubMed

    Baker, Anthony L; Ezzahir, Jessica; Gardiner, Christopher; Shipton, Warren; Warner, Jeffrey M

    2015-01-01

    Factors responsible for the spatial and temporal clustering of Burkholderia pseudomallei in the environment remain to be elucidated. Whilst laboratory based experiments have been performed to analyse survival of the organism in various soil types, such approaches are strongly influenced by alterations to the soil micro ecology during soil sanitisation and translocation. During the monsoonal season in Townsville, Australia, B. pseudomallei is discharged from Castle Hill (an area with a very high soil prevalence of the organism) by groundwater seeps and is washed through a nearby area where intensive sampling in the dry season has been unable to detect the organism. We undertook environmental sampling and soil and plant characterisation in both areas to ascertain physiochemical and macro-floral differences between the two sites that may affect the prevalence of B. pseudomallei. In contrast to previous studies, the presence of B. pseudomallei was correlated with a low gravimetric water content and low nutrient availability (nitrogen and sulphur) and higher exchangeable potassium in soils favouring recovery. Relatively low levels of copper, iron and zinc favoured survival. The prevalence of the organism was found to be highest under the grasses Aristida sp. and Heteropogon contortus and to a lesser extent under Melinis repens. The findings of this study indicate that a greater variety of factors influence the endemicity of melioidosis than has previously been reported, and suggest that biogeographical boundaries to the organisms' distribution involve complex interactions. PMID:26398904

  4. Factors that influence the hydrologic recovery of wetlands in the Northern Tampa Bay area, Florida

    USGS Publications Warehouse

    Metz, P.A.

    2011-01-01

    Although of less importance than the other three factors, a low-lying topographical position benefited the hydrologic condition of several of the study wetlands (S-68 Cypress and W-12 Cypress) both before and after the reductions in groundwater withdrawals. Compared to wetlands in a higher topographical position, those in a lower position had longer hydroperiods because of their greater ability to receive more runoff from higher elevation wetlands and to establish surface-water connections to other isolated wetlands and surface-water bodies through low-lying surface-water channels during wet conditions. In addition, wetlands in low-lying areas benefited from groundwater inflow when groundwater levels were higher than wetland water levels.

  5. Geophysical features influence the climate change sensitivity of northern Wisconsin pine and oak forests.

    PubMed

    Tweiten, Michael A; Calcote, Randy R; Lynch, Elizabeth A; Hotchkiss, Sara C; Schuurman, Gregor W

    2015-10-01

    Landscape-scale vulnerability assessment from multiple sources, including paleoecological site histories, can inform climate change adaptation. We used an array of lake sediment pollen and charcoal records to determine how soils and landscape factors influenced the variability of forest composition change over the past 2000 years. The forests in this study are located in northwestern Wisconsin on a sandy glacial outwash plain. Soils and local climate vary across the study area. We used the Natural Resource Conservation Service's Soil Survey Geographic soil database and published fire histories to characterize differences in soils and fire history around each lake site. Individual site histories differed in two metrics of past vegetation dynamics: the extent to which white pine (Pinus strobus) increased during the Little Ice Age (LIA) climate period and the volatility in the rate of change between samples at 50-120 yr intervals. Greater increases of white pine during the LIA occurred on sites with less sandy soils (R² = 0.45, P < 0.0163) and on sites with relatively warmer and drier local climate (R² = 0.55, P < 0.0056). Volatility in the rate of change between samples was positively associated with LIA fire frequency (R² = 0.41, P < 0.0256). Over multi-decadal to centennial timescales, forest compositional change and rate-of-change volatility were associated with higher fire frequency. Over longer (multi-centennial) time frames, forest composition change, especially increased white pine, shifted most in sites with more soil moisture. Our results show that responsiveness of forest composition to climate change was influenced by soils, local climate, and fire. The anticipated climatic changes in the next century will not produce the same community dynamics on the same soil types as in the past, but understanding past dynamics and relationships can help us assess how novel factors and combinations of factors in the future may influence various site types. Our

  6. Influence of the external DEM on PS-InSAR processing and results on Northern Appennine slopes

    NASA Astrophysics Data System (ADS)

    Bayer, B.; Schmidt, D. A.; Simoni, A.

    2014-12-01

    We present an InSAR analysis of slow moving landslide in the Northern Appennines, Italy, and assess the dependencies on the choice of DEM. In recent years, advanced processing techniques for synthetic aperture radar interferometry (InSAR) have been applied to measure slope movements. The persistent scatterers (PS-InSAR) approach is probably the most widely used and some codes are now available in the public domain. The Stanford method of Persistent Scatterers (StamPS) has been successfully used to analyze landslide areas. One problematic step in the processing chain is the choice of an external DEM that is used to model and remove the topographic phase in a series of interferograms in order to obtain the phase contribution caused by surface deformation. The choice is not trivial, because the PS InSAR results differ significantly in terms of PS identification, positioning, and the resulting deformation signal. We use four different DEMs to process a set of 18 ASAR (Envisat) scenes over a mountain area (~350 km2) of the Northern Appennines of Italy, using StamPS. Slow-moving landslides control the evolution of the landscape and cover approximately 30% of the territory. Our focus in this presentation is to evaluate the influence of DEM resolution and accuracy by comparing PS-InSAR results. On an areal basis, we perform a statistical analysis of displacement time-series to make the comparison. We also consider two case studies to illustrate the differences in terms of PS identification, number and estimated displacements. It is clearly shown that DEM accuracy positively influences the number of PS, while line-of-sight rates differ from case to case and can result in deformation signals that are difficult to interpret. We also take advantage of statistical tools to analyze the obtained time-series datasets for the whole study area. Results indicate differences in the style and amount of displacement that can be related to the accuracy of the employed DEM.

  7. Age at Menarche and Factors that Influence It: A Study among Female University Students in Tamale, Northern Ghana

    PubMed Central

    Ameade, Evans Paul Kwame; Garti, Helene Akpene

    2016-01-01

    Introduction Age at menarche reflects the health status of a population. This marks the beginning of sexual maturation and is affected by nutritional status and prevailing environmental conditions. This study measured the menarcheal age of female undergraduate students in northern Ghana and explored factors that could impact on the onset of menarche. Method GraphPad 5.01 was used to analyze data collected from 293 randomly selected female university students in a cross-sectional study using a semi-structured questionnaire. Association between different variables was tested using appropriate statistical tests. Results The mean recall age at menarche of participants in this study was 13.66 ±1.87 years for a female population of mean age, 23.04±5.07 years. Compared to female students who lived in rural settings, urban and suburban areas dwellers significantly recorded earlier menarche (p = 0.0006). Again, females from high income earning families experienced menarche earlier than those who were born to or lived with lower income earners (p = 0.003). Lower menarcheal age increased risk of experiencing menstrual pain prior to menses rather than during menstrual flow for dysmenorrhic females. (13.52±2.052 vrs 13.63±1.582 year; χ2 = 7.181, df = 2, p = 0.028). Conclusion Mean menarcheal age of female university students in northern Ghana was 13.66 years. Females from urban areas and high income families had earlier menarche. Compared to the very first Ghanaian study reported in 1989, the menarcheal age decline was 0.11 year per decade. PMID:27171234

  8. Forecasting the major influences of predation and environment on cod recovery in the northern Gulf of St. Lawrence.

    PubMed

    Bousquet, Nicolas; Chassot, Emmanuel; Duplisea, Daniel E; Hammill, Mike O

    2014-01-01

    The northern Gulf of St. Lawrence (NGSL) stock of Atlantic cod (Gadus morhua), historically the second largest cod population in the Western Atlantic, has known a severe collapse during the early 1990 s and is currently considered as endangered by the Committee on the Status of Endangered Wildlife in Canada. As for many fish populations over the world which are currently being heavily exploited or overfished, urgent management actions in the form of recovery plans are needed for restoring this stock to sustainable levels. Stochastic projections based on a statistical population model incorporating predation were conducted over a period of 30 years (2010-2040) to assess the expected outcomes of alternative fishing strategies on the stock recovery under different scenarios of harp seal (Pagophilus groenlandicus) abundance and environmental conditions. This sensitivity study shows that water temperature is key in the rebuilding of the NGSL cod stock. Model projections suggest that maintaining the current management practice under cooler water temperatures is likely to maintain the species in an endangered status. Under current or warmer conditions in the Gulf of St. Lawrence, partial recovery might only be achieved by significant reductions in both fishing and predation pressure. In the medium-term, a management strategy that reduces catch could be favoured over a complete moratorium so as to minimize socio-economic impacts on the industry. PMID:24523852

  9. Forecasting the Major Influences of Predation and Environment on Cod Recovery in the Northern Gulf of St. Lawrence

    PubMed Central

    Bousquet, Nicolas; Chassot, Emmanuel; Duplisea, Daniel E.; Hammill, Mike O.

    2014-01-01

    The northern Gulf of St. Lawrence (NGSL) stock of Atlantic cod (Gadus morhua), historically the second largest cod population in the Western Atlantic, has known a severe collapse during the early 1990 s and is currently considered as endangered by the Committee on the Status of Endangered Wildlife in Canada. As for many fish populations over the world which are currently being heavily exploited or overfished, urgent management actions in the form of recovery plans are needed for restoring this stock to sustainable levels. Stochastic projections based on a statistical population model incorporating predation were conducted over a period of 30 years (2010–2040) to assess the expected outcomes of alternative fishing strategies on the stock recovery under different scenarios of harp seal (Pagophilus groenlandicus) abundance and environmental conditions. This sensitivity study shows that water temperature is key in the rebuilding of the NGSL cod stock. Model projections suggest that maintaining the current management practice under cooler water temperatures is likely to maintain the species in an endangered status. Under current or warmer conditions in the Gulf of St. Lawrence, partial recovery might only be achieved by significant reductions in both fishing and predation pressure. In the medium-term, a management strategy that reduces catch could be favoured over a complete moratorium so as to minimize socio-economic impacts on the industry. PMID:24523852

  10. Post-wildfire natural restoration of riparian vegetation under stable hydro-geomorphic conditions: Nahal Grar, Northern Negev Desert, Israel

    NASA Astrophysics Data System (ADS)

    Egozi, Roey

    2015-04-01

    Wildfires are common to the Mediterranean region due to its defined dry season and long historical anthropogenic activities. Most of post-wildfire studies focus on mountains areas and thus refer to the hill-slope and its physical characteristics, e.g. morphology, length, angles, and aspect; its soil characteristics, e.g. type, infiltration rate, repellency; and its vegetative covers, e.g. planted trees vs. natural forest or native vs. exotic vegetation. In contrary there is very limited literature focusing on ecological and hydro-geomorphic aspects of post-wildfire of riparian vegetation / zone probably because of its negligible burned area relative to the spread of the fire, sometimes, over the whole watershed area. The limited literature on the topic is surprising given the fact that riparian vegetation zone has been acknowledged as a unique and important habitat supporting rich biodiversity. Herein we report on a wildfire event occurred on October 14th 2009 in a river section of Nahal Grar, Northern Negev Desert, Israel. The wildfire although was limited in its area (only 3 hectare) extended over the channel alone from bank to bank and thus provide a unique case study of completely burn down of riparian vegetation, mainly dense stands of Common Red (Australis Phragmites. Therefore a detailed study of this event provides an opportunity to tackle one of the basics questions which is determining the rate of natural restoration process that act at the immediate time after the wildfire event occurred. This type of information is most valuable to professional and stakeholders for better management of post-fire riparian zones. The results of the study suggest that under stable conditions, i.e. no major flood events occurred; disturbance time was short and ranged over 200 days due to, almost, immediate recovery of the riparian vegetation. However the re-growth of the riparian vegetation was not even but rather deferential and more complex then reported in the literature

  11. Influence of seasonal forcing on habitat use by bottlenose dolphins Tursiops truncatus in the Northern Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Bearzi, Giovanni; Azzellino, Arianna; Politi, Elena; Costa, Marina; Bastianini, Mauro

    2008-12-01

    Bottlenose dolphins are the only cetaceans regularly observed in the northern Adriatic Sea, but they survive at low densities and are exposed to significant threats. This study investigates some of the factors that influence habitat use by the animals in a largely homogeneous environment by combining dolphin data with hydrological and physiographical variables sampled from oceanographic ships. Surveys were conducted year-round between 2003 and 2006, totalling 3,397 km of effort. Habitat modelling based on a binary stepwise logistic regression analysis predicted between 81% and 93% of the cells where animals were present. Seven environmental covariates were important predictors: oxygen saturation, water temperature, density anomaly, gradient of density anomaly, turbidity, distance from the nearest coast and bottom depth. The model selected consistent predictors in spring and summer. However, the relationship (inverse or direct) between each predictor and dolphin presence varied among seasons, and different predictors were selected in fall. This suggests that dolphin distribution changed depending on seasonal forcing. As the study area is relatively uniform in terms of bottom topography, habitat use by the animals seems to depend on complex interactions among hydrological variables, caused primarily by seasonal change and likely to determine shifts in prey distribution.

  12. Influence of salinity, bottom topography, and tides on locations of estuarine turbidity maxima in northern San Francisco Bay

    USGS Publications Warehouse

    Schoellhamer, David H.

    2000-01-01

    Time series of salinity and suspended-solids concentration measured at four locations and vertical profiles of salinity and suspended-solids concentration measured during 48 water-quality cruises from January 1993 to September 1997 are analyzed to describe the influence of salinity, bottom topography, and tides on locations of estuarine turbidity maxima in northern San Francisco Bay, California. Estuarine turbidity maxima form when salinity is present but they are not associated with a singular salinity. Bottom topography enhances salinity stratification, gravitational circulation and estuarine turbidity maxima formation seaward of sills. The spring/neap tidal cycle affects locations of estuarine turbidity maxima. Salinity stratification in Carquinez Strait, which is seaward of a sill, is greatest during neap tides, which is the only time when tidally averaged suspended-solids concentration in Carquinez Strait was less than that observed landward at Mallard Island. Spring tides cause the greatest vertical mixing and suspended-solids concentration in Carquinez Strait. Therefore, surface estuarine turbidity maxima always were located in or near the Strait (seaward of Middle Ground) during spring tide cruises, regardless of salinity. During neap tides, surface estuarine turbidity maxima always were observed in the landward half of the study area (landward of Middle Ground) and between 0–2 practical salinity units.

  13. Influence of the Atchafalaya River on recent evolution of the chenier-plain inner continental shelf, northern Gulf of Mexico

    USGS Publications Warehouse

    Draut, A.E.; Kineke, G.C.; Velasco, D.W.; Allison, M.A.; Prime, R.J.

    2005-01-01

    This study examines the influence of the Atchafalaya River, a major distributary of the Mississippi River, on stratigraphic evolution of the inner continental shelf in the northern Gulf of Mexico. Sedimentary, geochemical, and shallow acoustic data are used to identify the western limit of the distal Atchafalaya subaqueous delta, and to estimate the proportion of the Atchafalaya River's sediment load that accumulates on the inner shelf seaward of Louisiana's chenier-plain coast. The results demonstrate a link between sedimentary facies distribution on the inner shelf and patterns of shoreline accretion and retreat on the chenier plain. Mudflat progradation on the eastern chenier-plain coast corresponds to the location of deltaic mud accumulation on the inner shelf. On the central chenier-plain shelf, west of the subaqueous delta, relict sediment is exposed that was originally deposited between ???1200 and 600 years BP during activity of the Lafourche lobe of the Mississippi Delta complex. Mass-balance calculations indicate that the eastern chenier-plain inner shelf and coastal zone form a sink for 7??2% of the sediment load carried by the Atchafalaya River. ?? 2004 Elsevier Ltd. All rights reserved.

  14. Influence of sediment characteristics on the composition of soft-sediment intertidal communities in the northern Gulf of Mexico

    PubMed Central

    Henkel, Jessica R.; Sigel, Bryan J.; Taylor, Caz M.

    2015-01-01

    Benthic infaunal communities are important components of coastal ecosystems. Understanding the relationships between the structure of these communities and characteristics of the habitat in which they live is becoming progressively more important as coastal systems face increasing stress from anthropogenic impacts and changes in climate. To examine how sediment characteristics and infaunal community composition were related along the northern Gulf of Mexico coast, we sampled intertidal infaunal communities at seven sites covering common habitat types at a regional scale. Across 69 samples, the communities clustered into four distinct groups on the basis of faunal composition. Nearly 70% of the variation in the composition of the communities was explained by salinity, median grain size, and total organic content. Our results suggest that at a regional level coarse habitat characteristics are able to explain a large amount of the variation among sites in infaunal community structure. By examining the relationships between infaunal communities and their sedimentary habitats, we take a necessary first step that will allow the exploration of how changes in habitat and community composition influence higher trophic levels and ecosystem scale processes. PMID:26157603

  15. Influence of lithology on hillslope morphology and response to tectonic forcing in the northern Sierra Nevada of California

    NASA Astrophysics Data System (ADS)

    Hurst, Martin D.; Mudd, Simon M.; Yoo, Kyungsoo; Attal, Mikael; Walcott, Rachel

    2013-06-01

    Many geomorphic studies assume that bedrock geology is not a first-order control on landscape form in order to isolate drivers of geomorphic change (e.g., climate or tectonics). Yet underlying geology may influence the efficacy of soil production and sediment transport on hillslopes. We performed quantitative analysis of LiDAR digital terrain models to examine the topographic form of hillslopes in two distinct lithologies in the Feather River catchment in northern California, a granodiorite pluton and metamorphosed volcanics. The two sites, separated by <2 km and spanning similar elevations, were assumed to have similar climatic histories and are experiencing a transience in landscape evolution characterized by a propagating incision wave in response to accelerated surface uplift c. 5 Ma. Responding to increased incision rates, hillslopes in granodiorite tend to have morphology similar to model predictions for steady state hillslopes, suggesting that they adjust rapidly to keep pace with the incision wave. By contrast, hillslopes in metavolcanics exhibit high gradients but lower hilltop curvature indicative of ongoing transient adjustment to incision. We used existing erosion rate data and the curvature of hilltops proximal to the main channels (where hillslopes have most likely adjusted to accelerated erosion rates) to demonstrate that the sediment transport coefficient is higher in granodiorite (8.8 m2 ka-1) than in metavolcanics (4.8 m2 ka-1). Hillslopes in both lithologies get shorter (i.e., drainage density increases) with increasing erosion rates.

  16. Grandmothers as gatekeepers? The role of grandmothers in influencing health-seeking for mothers and newborns in rural northern Ghana.

    PubMed

    Gupta, Mira L; Aborigo, Raymond Akawire; Adongo, Philip Baba; Rominski, Sarah; Hodgson, Abraham; Engmann, Cyril M; Moyer, Cheryl A

    2015-10-01

    Previous research suggests that care-seeking in rural northern Ghana is often governed by a woman's husband or compound head. This study was designed to explore the role grandmothers (typically a woman's mother-in-law) play in influencing maternal and newborn healthcare decisions. In-depth interviews were conducted with 35 mothers of newborns, 8 traditional birth attendants and local healers, 16 community leaders and 13 healthcare practitioners. An additional 18 focus groups were conducted with stakeholders such as household heads, compound leaders and grandmothers. In this region, grandmothers play many roles. They may act as primary support providers to pregnant mothers, care for newborns following delivery, preserve cultural traditions and serve as repositories of knowledge on local medicine. Grandmothers may also serve as gatekeepers for health-seeking behaviour, especially with regard to their daughters and daughters-in-law. This research also sheds light on the potential gap between health education campaigns that target mothers as autonomous decision-makers, and the reality of a more collectivist community structure in which mothers rarely make such decisions without the support of other community members. PMID:25635475

  17. Distinguishing between climatic and tectonic influences on topography: Best practices and application to the Northern Bolivian Andes

    NASA Astrophysics Data System (ADS)

    Gasparini, N. M.; Whipple, K. X.

    2015-12-01

    The hypothesis that high rainfall rates have the power to drive erosion and shape landscapes is tantalizing. However, definitive support for this hypothesis has been somewhat elusive, in part because high rainfall rates often occur in areas of high rock uplift rates. Here we present a number of best practices, developed from theory and landscape evolution modeling, that can be used to decipher whether climate, tectonics, or both importantly affect landscape morphology and evolution. For illustration we assume that there is a single, dominant gradient in both rainfall and rock uplift rates across the landscape. We quantify the morphology of rivers using the normalized channel steepness index, ksn, or channel slope normalized by drainage area. If rainfall influences landscape evolution solely through the production of runoff and fluvial discharge, then ksn is inversely proportional to the upstream averaged rainfall rate. In contrast, ksn is directly proportional to the local rock uplift rate. Exploring patterns in channels that primarily flow perpendicular to the gradient in forcing and channels that flow parallel to the gradient in forcing, illustrates the influence of different drivers. In channels that flow in the direction of the gradient, the rock uplift forcing should have a greater impact on channel form. However, when comparing among channels that flow perpendicular to the gradient, ksn should vary with the local rainfall rate. We apply these ideas in the Eastern Cordillera of the Northern Bolivian Andes, where modern rainfall rates and hypothesized rock uplift rates vary in the same dominant direction. We explore the morphology of channels that are both parallel and perpendicular to the gradient in forcings and find that the pattern of rock uplift dominates the morphology of the landscape, but that climate likely has a secondary effect. Using published erosion rate data from detrital 10Be, we find no correlation between rainfall and erosion rates.

  18. Influences of Northern Hemisphere Sea-Ice Change on Atmospheric Circulation

    NASA Astrophysics Data System (ADS)

    Hoshi, K.; Ukita, J.; Honda, M.; Iwamoto, K.; Nakamura, T.; Yamazaki, K.; Miyoshi, Y.; Ogawa, Y.

    2014-12-01

    Evidence from both observations and model results suggests a link between changes in the Arctic sea ice conditions and atmospheric circulation in the NH mid latitudes with its possible impacts on severe winters and extreme weather events. This study investigates underlying mechanisms for this Arctic-midlatitudes climate connection based on numerical experiments using a high-top AGCM. We compare and evaluate results from two sets of perpetual simulations (60yrs run each), one with an annual cycle of sea ice conditions from the period of 1979-1983 and the other from the 2005-2009 period while other variables and parameters including SST and GHGs are fixed.Results from the numerical experiments show that the Arctic sea ice reduction leads to cold winters in the mid-latitude land areas centered in Siberia, Europe and the North America. The winter (DJF) mean temperature at 850 hPa averaged over the mid-latitude continents decreases by about 0.4 K associated due solely to sea ice reduction.The analysis based on a wave-activity flux indicates that this cooling is due to low-level cold advection. In early winter negative geopotential height anomalies over Siberia and the North America develop as a stationary Rossby wave response to anomalous turbulent surface heat fluxes associated with the sea-ice reduction in the Barents and Kala Seas. As winter progresses further wave propagation acts to intensify positive geopotential height anomalies over the high Arctic, which eventually leads to cold advections in the lower troposphere. In addition, we identify a pathway via the stratosphere which appears to aid this intensification of positive geopotential height anomalies.Observations in general support a similar relationship. For example, on interannual timescale there is a significant positive relationship between the September NH SIE time series and surface temperatures in continental regions.Our results have significant implications that sea ice can be used as a basis for mid

  19. Factors influencing nesting success of king eiders on northern Alaska's Coastal Plain

    USGS Publications Warehouse

    Bentzen, R.L.; Powell, A.N.; Suydam, R.S.

    2008-01-01

    visits in future studies and to consider them as a possible negative bias in estimated nest survival. Future models of the impacts of development within the breeding grounds of king eider should consider the influence of humans in the vicinity of nests.

  20. Short-term Influences on Suspended Particulate Matter Distribution in the Northern Gulf of Mexico: Satellite and Model Observations

    PubMed Central

    D'Sa, Eurico J.; Ko, Dong S.

    2008-01-01

    Energetic meteorological events such as frontal passages and hurricanes often impact coastal regions in the northern Gulf of Mexico that influence geochemical processes in the region. Satellite remote sensing data such as winds from QuikSCAT, suspended particulate matter (SPM) concentrations derived from SeaWiFS and the outputs (sea level and surface ocean currents) of a nested navy coastal ocean model (NCOM) were combined to assess the effects of frontal passages between 23-28 March 2005 on the physical properties and the SPM characteristics in the northern Gulf of Mexico. Typical changes in wind speed and direction associated with frontal passages were observed in the latest 12.5 km wind product from QuikSCAT with easterly winds before the frontal passage undergoing systematic shifts in direction and speed and turning northerly, northwesterly during a weak and a strong front on 23 and 27 March, respectively. A quantitative comparison of model sea level results with tide gauge observations suggest better correlations near the delta than in the western part of the Gulf with elevated sea levels along the coast before the frontal passage and a large drop in sea level following the frontal passage on 27 March. Model results of surface currents suggested strong response to wind forcing with westward and onshore currents before the frontal passage reversing into eastward, southeastward direction over a six day period from 23 to 28 March 2005. Surface SPM distribution derived from SeaWiFS ocean color data for two clear days on 23 and 28 March 2005 indicated SPM plumes to be oriented with the current field with increasing concentrations in nearshore waters due to resuspension and discharge from the rivers and bays and its seaward transport following the frontal passage. The backscattering spectral slope γ, a parameter sensitive to particle size distribution also indicated lower γ values (larger particles) in nearshore waters that decreased offshore (smaller particles

  1. Germanium-silicon fractionation in a river-influenced continental margin: The Northern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Baronas, J. Jotautas; Hammond, Douglas E.; Berelson, William M.; McManus, James; Severmann, Silke

    2016-04-01

    In this study we have sampled the water column and sediments of the Gulf of Mexico to investigate the effects of high riverine terrigenous load and sediment redox conditions on the cycling of Ge and Si. Water column Ge/Si ratios across the Gulf of Mexico continental shelf range from 1.9 to 25 μmol/mol, which is elevated compared to the global ocean value of 0.7 μmol/mol. The Ge enrichment in the Gulf of Mexico seawater is primarily due to anthropogenic contamination of the Mississippi river, which is the main Ge and Si source to the area, and to a smaller extent due to discrimination against Ge during biogenic silica (bSi) production (Ge/Si = 1.2-1.8 μmol/mol), especially by radiolarians and siliceous sponges (Ge/Si = 0.6-1.1 μmol/mol). Most sediment pore waters (Ge/Si = 0.3-4.5 μmol/mol) and sediment incubation experiments (benthic flux Ge/Si = 0.9-1.2 μmol/mol) indicate precipitation of authigenic phases that sequester Ge from pore waters (non-opal sink). This process appears to be independent of oxidation-reduction reactions and suggests that authigenic aluminosilicate formation (reverse weathering) may be the dominant Ge sink in marine sediments. Compilation of previously published data shows that in continental margins, non-opal Ge burial flux is controlled by bSi supply, while in open ocean sediments it is 10-100 times lower and most likely limited by the supply of lithogenic material. We provide a measurement-based estimate of the global non-opal Ge burial flux as 4-32 Mmol yr-1, encompassing the 2-16 Mmol yr-1 needed to keep the global marine Ge cycle at steady state.

  2. THE INFLUENCE OF FOLD AND FRACTURE DEVELOPMENT ON RESERVOIR BEHAVIOR OF THE LISBURNE GROUP OF NORTHERN ALASKA

    SciTech Connect

    Wesley K. Wallace; Catherine L. Hanks; Jerry Jensen; Michael T. Whalen

    2002-01-01

    The Carboniferous Lisburne Group is a major carbonate reservoir unit in northern Alaska. The Lisburne is detachment folded where it is exposed throughout the northeastern Brooks Range, but is relatively undeformed in areas of current production in the subsurface of the North Slope. The objectives of this study are to develop a better understanding of four major aspects of the Lisburne: (1) The geometry and kinematics of detachment folds and their truncation by thrust faults. (2) The influence of folding on fracture patterns. (3) The influence of deformation on fluid flow. (4) Lithostratigraphy and its influence on folding, faulting, fracturing, and reservoir characteristics. The Lisburne in the main axis of the Brooks Range is characteristically deformed into imbricate thrust sheets with asymmetrical hanging wall anticlines and footwall synclines. In contrast, the Lisburne in the northeastern Brooks Range is characterized by symmetrical detachment folds. The focus of our 2000 field studies was at the boundary between these structural styles in the vicinity of Porcupine Lake, in the Arctic National Wildlife Refuge. The northern edge of thrust-truncated folds in Lisburne is marked by a local range front that likely represents an eastward continuation of the central Brooks Range front. This is bounded to the north by a gently dipping panel of Lisburne with local asymmetrical folds. The leading edge of the flat panel is thrust over Permian to Cretaceous rocks in a synclinal depression. These younger rocks overlie symmetrically detachment-folded Lisburne, as is extensively exposed to the north. Six partial sections were measured in the Lisburne of the flat panel and local range front. The Lisburne here is about 700 m thick and is interpreted to consist primarily of the Wachsmuth and Alapah Limestones, with only a thin veneer of Wahoo Limestone. The Wachsmuth (200 m) is gradational between the underlying Missippian Kayak Shale and the overlying Mississippian Alapah, and

  3. The influence of body condition on the fasting energy metabolism of nonpregnant, nonlactating dairy cows.

    PubMed

    Birnie, J W; Agnew, R E; Gordon, F J

    2000-06-01

    The objective of this experiment was to investigate the effect of cow body condition score on fasting heat production. Twelve nonpregnant, nonlactating Holstein-Friesian cows were selected from within the dairy herd at the Agricultural Research Institute of Northern Ireland. Six of these animals (group A) had condition scores > or = 4.5, and the remainder (group B) had condition scores <2. All cows were offered dried grass pellets at estimated maintenance energy level (0.58 MJ of metabolizable energy/kg(0.75)) for a minimum of 21 d. The diet also supplied 2.5 times the metabolizable protein requirement for maintenance. Following this, each cow underwent a 5-d fast in open circuit respiration calorimeters during which fasting heat production (FHP) was measured. On completion of measurement, group A was fed to reduce condition score (CS) below 2, while group B was fed to raise each individual condition score above 4.5. When the appropriate condition scores were achieved, dried grass pellets were again offered at maintenance for a minimum of 21 d, and fasting heat production was measured. It was observed that fasting heat production (MJ/kg(0.75)) was significantly higher for cows with low body condition (<2; ultrasonic fat depth < or = 2.9 mm) compared with cows displaying high body condition (> or = 4.5; ultrasonic fat depth > or = 8.2 mm). A linear relationship between condition score and fasting heat production (MJ/kg(0.75)) was defined by regression analysis as; FHP (MJ/kg(0.75)) = 0.501(SE 0.0121) - 0.030CS (SE 0.0035). PMID:10877386

  4. Calcareous Bio-Concretions in the Northern Adriatic Sea: Habitat Types, Environmental Factors that Influence Habitat Distributions, and Predictive Modeling.

    PubMed

    Falace, Annalisa; Kaleb, Sara; Curiel, Daniele; Miotti, Chiara; Galli, Giovanni; Querin, Stefano; Ballesteros, Enric; Solidoro, Cosimo; Bandelj, Vinko

    2015-01-01

    Habitat classifications provide guidelines for mapping and comparing marine resources across geographic regions. Calcareous bio-concretions and their associated biota have not been exhaustively categorized. Furthermore, for management and conservation purposes, species and habitat mapping is critical. Recently, several developments have occurred in the field of predictive habitat modeling, and multiple methods are available. In this study, we defined the habitats constituting northern Adriatic biogenic reefs and created a predictive habitat distribution model. We used an updated dataset of the epibenthic assemblages to define the habitats, which we verified using the fuzzy k-means (FKM) clustering method. Redundancy analysis was employed to model the relationships between the environmental descriptors and the FKM membership grades. Predictive modelling was carried out to map habitats across the basin. Habitat A (opportunistic macroalgae, encrusting Porifera, bioeroders) characterizes reefs closest to the coastline, which are affected by coastal currents and river inputs. Habitat B is distinguished by massive Porifera, erect Tunicata, and non-calcareous encrusting algae (Peyssonnelia spp.). Habitat C (non-articulated coralline, Polycitor adriaticus) is predicted in deeper areas. The onshore-offshore gradient explains the variability of the assemblages because of the influence of coastal freshwater, which is the main driver of nutrient dynamics. This model supports the interpretation of Habitat A and C as the extremes of a gradient that characterizes the epibenthic assemblages, while Habitat B demonstrates intermediate characteristics. Areas of transition are a natural feature of the marine environment and may include a mixture of habitats and species. The habitats proposed are easy to identify in the field, are related to different environmental features, and may be suitable for application in studies focused on other geographic areas. The habitat model outputs

  5. Calcareous Bio-Concretions in the Northern Adriatic Sea: Habitat Types, Environmental Factors that Influence Habitat Distributions, and Predictive Modeling

    PubMed Central

    Falace, Annalisa; Kaleb, Sara; Curiel, Daniele; Miotti, Chiara; Galli, Giovanni; Querin, Stefano; Ballesteros, Enric; Solidoro, Cosimo; Bandelj, Vinko

    2015-01-01

    Habitat classifications provide guidelines for mapping and comparing marine resources across geographic regions. Calcareous bio-concretions and their associated biota have not been exhaustively categorized. Furthermore, for management and conservation purposes, species and habitat mapping is critical. Recently, several developments have occurred in the field of predictive habitat modeling, and multiple methods are available. In this study, we defined the habitats constituting northern Adriatic biogenic reefs and created a predictive habitat distribution model. We used an updated dataset of the epibenthic assemblages to define the habitats, which we verified using the fuzzy k-means (FKM) clustering method. Redundancy analysis was employed to model the relationships between the environmental descriptors and the FKM membership grades. Predictive modelling was carried out to map habitats across the basin. Habitat A (opportunistic macroalgae, encrusting Porifera, bioeroders) characterizes reefs closest to the coastline, which are affected by coastal currents and river inputs. Habitat B is distinguished by massive Porifera, erect Tunicata, and non-calcareous encrusting algae (Peyssonnelia spp.). Habitat C (non-articulated coralline, Polycitor adriaticus) is predicted in deeper areas. The onshore-offshore gradient explains the variability of the assemblages because of the influence of coastal freshwater, which is the main driver of nutrient dynamics. This model supports the interpretation of Habitat A and C as the extremes of a gradient that characterizes the epibenthic assemblages, while Habitat B demonstrates intermediate characteristics. Areas of transition are a natural feature of the marine environment and may include a mixture of habitats and species. The habitats proposed are easy to identify in the field, are related to different environmental features, and may be suitable for application in studies focused on other geographic areas. The habitat model outputs

  6. Features of Duration and Borders of the Bedding of Snow Cover in the Conditions of Climatic Changes in the Territory of Northern Kazakhstan According to Land and Space Monitoring

    NASA Astrophysics Data System (ADS)

    Salnikov, Vitaliy; Turulina, Galina; Polyakova, Svetlana; Muratova, Nadiya; Kauazov, Azamat; Abugalieva, Aigul; Tazhibayeva, Tamara

    2014-05-01

    Precipitation and air temperature datasets from 34 meteorological stations were analyzed to reveal the regional climate changes at the territory in North Kazakhstan over the last 58 years (i.e., 1950-2008). Peculiarities and conditions of snow cover formation and melting have been analyzed at territory of Northern Kazakhstan using surface and space monitoring data. Methods of both the geo-informational processing of remote probing data and statistical processing of databases on snow cover, air temperature and precipitations have been used. Analysis of snow cover observations data for territory of Northern Kazakhstan has shown that the stable snow cover might be observed since the middle of November till the beginning of April. In a few last decades the tendency is observed for longevity decrease of snow cover bedding that appears to be on the background air temperature increase and insignificant increase of cold period precipitations due to the later bedding of the snow cover and its earlier destruction. Peculiarities of atmospheric circulation in Atlantic-Eurasian sector of Northern Semi sphere and their influence of formation of snow cover at territory of Northern Kazakhstan. The higher longevity of the snow cover bedding is defined by the predominance of E form circulation and lower longevity - by the predominance of W+C circulation form. Analysis conducted of the highest height of snow cover bedding has shown that for period of 1936-2012 in the most cases the statistically reliable decreasing trends are observed with the linear trend coefficients of 0,50 - 0,60 cm/year. The method is offered for determination of probable characteristics of the snow cover decade height. Using data of space monitoring are allocated the frontiers of snow cover bedding for the period of snow melting 1982-2008 and the snow cover melting maps are developed. The results further confirm the proposition that snow cover availability is an important and limiting factor in the generation

  7. Analysis of the Influence of Thermal Conditions on the Operation of Optoelectronic Devices

    NASA Astrophysics Data System (ADS)

    Ushakovskaya, E. D.

    2013-07-01

    The optoelectronic device has been considered from the viewpoint of system analysis. It has been shown that thermal conditions influence the transfer function of this system and, as a consequence, the desired signal. Moreover, the self-radiation of the device's elements, which also leads to a change in the output signal of the device, depends on the thermal conditions. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 86, No. 4, pp. 894-904, July-August, 2013.

  8. Influence of Body Condition on Influenza A Virus Infection in Mallard Ducks: Experimental Infection Data

    PubMed Central

    Arsnoe, Dustin M.; Ip, Hon S.; Owen, Jennifer C.

    2011-01-01

    Migrating waterfowl are implicated in the global spread of influenza A viruses (IAVs), and mallards (Anas platyrhynchos) are considered a particularly important IAV reservoir. Prevalence of IAV infection in waterfowl peaks during autumn pre-migration staging and then declines as birds reach wintering areas. Migration is energetically costly and birds often experience declines in body condition that may suppress immune function. We assessed how body condition affects susceptibility to infection, viral shedding and antibody production in wild-caught and captive-bred juvenile mallards challenged with low pathogenic avian influenza virus (LPAIV) H5N9. Wild mallards (n = 30) were separated into three experimental groups; each manipulated through food availability to a different condition level (−20%, −10%, and normal ±5% original body condition), and captive-bred mallards (n = 10) were maintained at normal condition. We found that wild mallards in normal condition were more susceptible to LPAIV infection, shed higher peak viral loads and shed viral RNA more frequently compared to birds in poor condition. Antibody production did not differ according to condition. We found that wild mallards did not differ from captive-bred mallards in viral intensity and duration of infection, but they did exhibit lower antibody titers and greater variation in viral load. Our findings suggest that reduced body condition negatively influences waterfowl host competence to LPAIV infection. This observation is contradictory to the recently proposed condition-dependent hypothesis, according to which birds in reduced condition would be more susceptible to IAV infection. The mechanisms responsible for reducing host competency among birds in poor condition remain unknown. Our research indicates body condition may influence the maintenance and spread of LPAIV by migrating waterfowl. PMID:21857940

  9. Influence of body condition on influenza A virus infection in mallard ducks: Experimental infection data

    USGS Publications Warehouse

    Arsnoe, Dustin M.; Ip, Hon S.; Owen, Jennifer C.

    2011-01-01

    Migrating waterfowl are implicated in the global spread of influenza A viruses (IAVs), and mallards (Anas platyrhynchos) are considered a particularly important IAV reservoir. Prevalence of IAV infection in waterfowl peaks during autumn pre-migration staging and then declines as birds reach wintering areas. Migration is energetically costly and birds often experience declines in body condition that may suppress immune function. We assessed how body condition affects susceptibility to infection, viral shedding and antibody production in wild-caught and captive-bred juvenile mallards challenged with low pathogenic avian influenza virus (LPAIV) H5N9. Wild mallards (n = 30) were separated into three experimental groups; each manipulated through food availability to a different condition level (-20%, -10%, and normal ±5% original body condition), and captive-bred mallards (n = 10) were maintained at normal condition. We found that wild mallards in normal condition were more susceptible to LPAIV infection, shed higher peak viral loads and shed viral RNA more frequently compared to birds in poor condition. Antibody production did not differ according to condition. We found that wild mallards did not differ from captive-bred mallards in viral intensity and duration of infection, but they did exhibit lower antibody titers and greater variation in viral load. Our findings suggest that reduced body condition negatively influences waterfowl host competence to LPAIV infection. This observation is contradictory to the recently proposed condition-dependent hypothesis, according to which birds in reduced condition would be more susceptible to IAV infection. The mechanisms responsible for reducing host competency among birds in poor condition remain unknown. Our research indicates body condition may influence the maintenance and spread of LPAIV by migrating waterfowl.

  10. Influence of body condition on influenza a virus infection in mallard ducks: Experimental infection data

    USGS Publications Warehouse

    Arsnoe, D.M.; Ip, H.S.; Owen, J.C.

    2011-01-01

    Migrating waterfowl are implicated in the global spread of influenza A viruses (IAVs), and mallards (Anas platyrhynchos) are considered a particularly important IAV reservoir. Prevalence of IAV infection in waterfowl peaks during autumn pre-migration staging and then declines as birds reach wintering areas. Migration is energetically costly and birds often experience declines in body condition that may suppress immune function. We assessed how body condition affects susceptibility to infection, viral shedding and antibody production in wild-caught and captive-bred juvenile mallards challenged with low pathogenic avian influenza virus (LPAIV) H5N9. Wild mallards (n = 30) were separated into three experimental groups; each manipulated through food availability to a different condition level (-20%, -10%, and normal ??5% original body condition), and captive-bred mallards (n = 10) were maintained at normal condition. We found that wild mallards in normal condition were more susceptible to LPAIV infection, shed higher peak viral loads and shed viral RNA more frequently compared to birds in poor condition. Antibody production did not differ according to condition. We found that wild mallards did not differ from captive-bred mallards in viral intensity and duration of infection, but they did exhibit lower antibody titers and greater variation in viral load. Our findings suggest that reduced body condition negatively influences waterfowl host competence to LPAIV infection. This observation is contradictory to the recently proposed condition-dependent hypothesis, according to which birds in reduced condition would be more susceptible to IAV infection. The mechanisms responsible for reducing host competency among birds in poor condition remain unknown. Our research indicates body condition may influence the maintenance and spread of LPAIV by migrating waterfowl. ?? 2011 Arsnoe et al.

  11. Maternal Condition Does Not Influence Birth Sex Ratios in Anubis Baboons (Papio anubis)

    PubMed Central

    Silk, Joan B.; Strum, Shirley C.

    2010-01-01

    Trivers and Willard predicted that when parental condition has differential effects on the fitness of male and female offspring, parents who are in good condition will bias investment toward the sex that benefits most from additional investment. Efforts to test predictions derived from Trivers and Willard's model have had mixed results, perhaps because most studies have relied on proxy measures of parental condition, such as dominance rank. Here, we examine the effects of female baboons condition on birth sex ratios and post-natal investment, based on visual assessments of maternal body condition. We find that local environmental conditions have significant effects on female condition, but maternal condition at conception has no consistent relationship with birth sex ratios. Mothers who are in poorer condition at the time of conception resume cycling significantly later than females who are in better condition, but the sex of their infants has no effect on the time to resumption of cycling. Thus, our findings provide strong evidence that maternal condition influences females' ability to reproduce, but females do not facultatively adjust the sex ratio of their offspring in relation to their dominance rank or current condition. PMID:20877648

  12. The impacts of the North American ice-sheet on glaciation conditions over northern Europe: an atmospheric circulation study with the LMDZ model

    NASA Astrophysics Data System (ADS)

    Beghin, Pauline; Charbit, Sylvie; Kageyama, Masa; Dumas, Christophe

    2015-04-01

    During the last glacial period (ca. 21 000 years ago), two continental-scale ice sheets covered Canada and northern Europe. It is now widely acknowledged that these past ice sheets exerted a strong influence on climate by causing changes in atmospheric and oceanic circulations. In turn, these changes may have impacted the development of the ice sheets themselves through a combination of different feedback mechanisms. The present study is designed to investigate the potential impact of the North American ice sheet on the surface mass balance (SMB) of the Eurasian ice sheet through simulated changes in the past glacial atmospheric circulation. Using the LMDz5 atmospheric circulation model, we carried out twelve experiments run under constant Last Glacial Maximum (LGM) conditions for insolation, greenhouse gases and ocean. In the all experiments, the Eurasian ice sheet is removed. The twelve experiments differ in the North American ice-sheet topography, ranging from a white and flat (present-day topography) ice sheet to a full-size LGM ice sheet. This experimental design allows to disentangle the albedo and the topographic impacts of the North American ice sheet onto the climate. The results are compared to our baseline experiment where both the North American and the Eurasian ice sheets have been removed. In summer, the sole albedo effect of the American ice sheet modifies the pattern of planetary waves with respect to the no-ice sheet case, causing a cooling of the Eurasian region. By contrast, the atmospheric circulation changes induced by the topography of the North American ice sheet imply summer warming in Northwestern Eurasia. In winter, the Scandinavian and the Barents-Kara regions respond differently to the albedo effect: in response to atmospheric circulation changes, Scandinavia warms up and precipitation is more abundant whereas Barents-Kara area cools down and gets drier. The height increase of the American ice sheet leads to less precipitation and

  13. Effects of climate warming, North Atlantic Oscillation, and El Niño-Southern Oscillation on thermal conditions and plankton dynamics in northern hemispheric lakes.

    PubMed

    Gerten, Dieter; Adrian, Rita

    2002-03-01

    Impacts of climate warming on freshwater ecosystems have been documented recently for a variety of sites around the globe. Here we provide a review of studies that report long-term (multidecadal) effects of warming trends on thermal properties and plankton dynamics in northern hemispheric lakes. We show that higher lake temperatures, shorter periods with ice cover, and shorter stagnation periods were common trends for lakes across the hemisphere in response to the warmer conditions. Only for shallow dimictic lakes was it observed that deep-water temperatures decreased. Moreover, it became evident that phytoplankton dynamics and primary productivity altered in conjunction with changes in lake physics. Algal spring blooms developed early and were more pronounced in several European lakes after mild winters with short ice cover periods, and primary productivity increased in North American lakes. Effects of elevated temperatures on zooplankton communities were seen in an early development of various species and groups, as is documented for cladocerans, copepods, and rotifers in European lakes. Furthermore, thermophile species reached higher abundance in warmer years. Obviously, the nature of responses is species specific, and depends on the detailed seasonal patterning of warming. Complex responses such as effects propagating across trophic levels are likely, indicating that observed climate-ecosystem relationships are not generally applicable. Nonetheless, the picture emerges that climate-driven changes in freshwater ecosystems may be synchronised to a certain extent among lakes even over great distances if climatic influences are not masked by anthropogenic impacts or differences in lake morphology. Macro-scale climatic fluctuations--such as the North Atlantic Oscillation or the El Niño-Southern Oscillation--were identified as the most important candidates responsible for such coherence, with the former predominating in Europe and the latter in North America. We

  14. Understanding the conditions for improvement: research to discover which context influences affect improvement success.

    PubMed

    Øvretveit, John

    2011-04-01

    Context can be defined as all factors that are not part of a quality improvement intervention itself. More research indicates which aspects are 'conditions for improvement', which influence improvement success. However, little is known about which conditions are most important, whether these are different for different quality interventions or whether some become less or more important at different times in carrying out an improvement. Knowing more about these conditions could help speed up and spread improvements and develop the science. This paper proposes ways to build knowledge about the conditions needed for different changes, and to create conditional-attribution explanations to provide qualified generalisations. It describes theory-based, non-experimental research designs. It also suggests that 'practical improvers' can make their changes more effective by reflecting on and revising their own 'assumption-theories' about the conditions which will help and hinder the improvements they aim to implement. PMID:21450764

  15. Understanding the conditions for improvement: research to discover which context influences affect improvement success

    PubMed Central

    2011-01-01

    Context can be defined as all factors that are not part of a quality improvement intervention itself. More research indicates which aspects are ‘conditions for improvement’, which influence improvement success. However, little is known about which conditions are most important, whether these are different for different quality interventions or whether some become less or more important at different times in carrying out an improvement. Knowing more about these conditions could help speed up and spread improvements and develop the science. This paper proposes ways to build knowledge about the conditions needed for different changes, and to create conditional-attribution explanations to provide qualified generalisations. It describes theory-based, non-experimental research designs. It also suggests that ‘practical improvers’ can make their changes more effective by reflecting on and revising their own ‘assumption-theories’ about the conditions which will help and hinder the improvements they aim to implement. PMID:21450764

  16. Maps showing ground-water conditions in the northern part of the Chinle area, Apache County, Arizona, 1976

    USGS Publications Warehouse

    Levings, G.W.; Farrar, C.D.

    1977-01-01

    The northern part of the Chinle area includes about 3,000 sq mi in northeastern Arizona and is entirely in the Navajo Indian Reservation. The main source of water is from the several aquifers that are made up of one or more formations. The aquifers are stacked one on the other and generally are not hydraulically connected. Information on the maps includes depth to water, altitude of the water level, and chemical quality of the water. Scale 1:125,000. (Woodard-USGS)

  17. Past Experience Influences the Processing of Stimulus Compounds in Human Pavlovian Conditioning

    ERIC Educational Resources Information Center

    Melchers, Klaus G.; Lachnit, Harold; Shanks, David R.

    2004-01-01

    In two human skin conductance conditioning experiments we investigated whether processing of stimulus compounds can be influenced by past experience. Participants were either pre-trained with a discrimination problem that could be solved elementally (A+, B-, AB+, C- in Experiment 1 and A+, AB+, C-, CB- in Experiment 2) or one that required a…

  18. A critical review of social and structural conditions that influence HIV risk among Mexican deportees

    PubMed Central

    Pinedo, Miguel; Burgos, José Luis; Ojeda, Victoria D.

    2014-01-01

    Mexican migrants who are deported from the US may be at elevated risk for HIV infection. Deportations of Mexican migrants by the US have reached record numbers. We critically reviewed existing literature to assess how social and structural conditions in post-deportation settings can influence Mexican deported migrants' HIV risk. We also identify critical research gaps and make research recommendations. PMID:24583278

  19. Antibacterial Properties of Copper Nanoparticle Dispersions: Influence of Synthesis Conditions and Physicochemical Characteristics

    NASA Astrophysics Data System (ADS)

    Godymchuk, A.; Frolov, G.; Gusev, A.; Zakharova, O.; Yunda, E.; Kuznetsov, D.; Kolesnikov, E.

    2015-11-01

    The production of bactericidal plasters, bandages and medicines with the inclusion of copper nanoparticles and copper ions may have a great potential in terms of their biomedical application. The work considers the influence of the synthesis conditions, size, aggregation status, and charge of nanoparticles in aqueous solutions as well as the type of microorganisms to the antibacterial properties of water suspensions of electroexplosive copper nanoparticles in the conditions in vitro in relation to strains Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus cereus. Water dispersions of copper nanoparticles were shown to inhibit the growth of test cells for both G+ and G- microbacteria but the degree of such an influence strongly depended on the type of a test strain. The authors have demonstrated that use of deeply purified water and alcohol-containing stabilizers at the synthesis of nanoparticles via metals electric erosion in the liquid prevents the copper nanoparticles coagulation and significantly influences on their physicochemical characteristics and, consequently, antibacterial properties.

  20. Influence of recruit condition on food competition and predation risk in a coral reef fish.

    PubMed

    Booth, David J; Beretta, Giglia A

    2004-07-01

    Settlement rate is considered to be a major determinant of the population structure of coral reef fishes. In this study, the effects of larval physiological condition on survival, predation risk and competitive ability are assessed for a small damselfish, Pomacentrus moluccensis. New settlers were collected and fed for 5 days to produce high and low condition (measured as lipid) treatment fish. In a field experiment, pairs (one high and one low condition fish) were transplanted to corals. Persistence over 2 weeks was much higher (100% vs. 25%) in high condition fish. In mixed groups in the laboratory, high condition fish were both aggressively dominant and consumed more of a limiting prey source than low condition fish. In addition, low condition fish were shown to be at much higher risk of predation. All of the low condition fish but only 33% of high condition fish in mixed groups were consumed by fish predators, and in a separate experiment, 73% of feeding strikes by predators were directed at low condition fish. Quality of new settlers can have an important influence on subsequent juvenile survival. The mechanisms for this effect are likely to include a combination of effects of condition on food competition and predation risk. PMID:15179583

  1. Length-weight relationships and condition factor of the eaglebeak pacu Ossubtus xinguense Jégu, 1992 (Characiformes, Serrasalmidae), an endangered species from Rio Xingu rapids, northern Brazil.

    PubMed

    Andrade, M C; Jesus, A J S; Giarrizzo, T

    2015-08-01

    This study reports on the length-weight relationships and condition factor for the endangered rheophilic fish Ossubtus xinguense Jégu from Rio Xingu rapids. This species is threatened by construction of the third largest hydroelectric in the world, the Belo Monte dam close to the city of Altamira, northern Brazil. Specimens were collected in the dry season between July 2012 and September 2012. Male specimens have body length larger than females, atypical in serrasalmid fishes, and different length-weight relationships were found between adult and juvenile specimens. This study presents the first biological characteristics for O. xinguense. PMID:26691082

  2. The influence of initial and surface boundary conditions on a model-generated January climatology

    NASA Technical Reports Server (NTRS)

    Wu, K. F.; Spar, J.

    1981-01-01

    The influence on a model-generated January climate of various surface boundary conditions, as well as initial conditions, was studied by using the GISS coarse-mesh climate model. Four experiments - two with water planets, one with flat continents, and one with mountains - were used to investigate the effects of initial conditions, and the thermal and dynamical effects of the surface on the model generated-climate. However, climatological mean zonal-symmetric sea surface temperature is used in all four runs over the model oceans. Moreover, zero ground wetness and uniform ground albedo except for snow are used in the last experiments.

  3. Association of vectors and environmental conditions during the emergence of Peruvian horse sickness orbivirus and Yunnan orbivirus in northern Peru.

    PubMed

    Méndez-López, María R; Attoui, Houssam; Florin, David; Calisher, Charles H; Florian-Carrillo, J Christian; Montero, Stephanie

    2015-12-01

    Since 1983, cases of diseased donkeys and horses with symptoms similar to those produced by alphaviruses were identified in two departments in northern Peru; however serological testing ruled out the presence of those viruses and attempts to isolate an agent were also unproductive. In 1997, also in northern Peru, two new orbiviruses were discovered, each recognized as a causative agent of neurological diseases in livestock and domestic animals and, at the same time, mosquitoes were found to be infected with these viruses. Peruvian horse sickness virus (PHSV) was isolated from pools of culicid mosquitoes, Aedes serratus and Psorophora ferox, and Yunnan virus (YUOV) was isolated from Aedes scapularis in the subtropical jungle (upper jungle) located on the slope between the east side of the Andes and the Amazonian basin in the Department of San Martín. Both viruses later were recovered from mosquitoes collected above the slope between the west side of the Andes and the coast (Department of Piura) in humid subtropical areas associated with the Piura River basin. In this region, PHSV was isolated from Anopheles albimanus and YUOV was isolated from Ae. scapularis. We discuss the ecology of vector mosquitoes during the outbreaks in the areas where these mosquitoes were found. PMID:26611971

  4. The Influences of The Continental Slope Geomorphology On The Deep Water Sediment System, Taking the Northern South China Slope for Example

    NASA Astrophysics Data System (ADS)

    liu, L.; Li, P.; Li, J.; Du, J.; Fu, M.

    2013-12-01

    The developing of deepwater sedimentary bodies have been affected by many factors, such as the tectonic evolution, conditions of the sediment supplying as well as the sea-level changes. In the researching of the sedimentary bodies on the continental slope system, there have been found that the degree of slope mould affect the building of those sedimentary bodies. Taking the Northern South China Slope for example, based on the high resolution marine geophysical data, including the multi-beam echo sounder, the sub-bottom profiler and the high-resolution 2D multi-channel seismic reflection sections, the geomorphological patterns of the study Field are interpreted in details, illuminated the types of those sedimentary bodies, the characteristic and the space distributions. Analyzed those influences factors on the deepwater depositional system of the geomorphology. Those geomorphological bodies zonation in the study area generally consistent with the upper part, the middle part and the lower part zoned for the continental slope of the South China Sea. In the upper part of the continental slope with a monocline shape (water depth: 200m~400m), there are sand waves and paleo-coral reefs, whereas in its lower part (water depth: 400m~670m) the seafloor is flat and no unfavourable geological bodies have been recognized. In the continental slope zone with fault terraces, the topography of the seafloor falls into pieces and submarine canyons, fault scarps, landslides and collapses and abrupt slopes are widely developed. At the two slope sides of the canyons landslides and piles of debris can be observed clearly. In the continental slope zone with turbidity current deposits, the seafloor is gentle. The down-cutting depth and width of the submarine canyons become small and disappear gradually. The main geo-hazard risks in this zone are the debris flow (turbidity-current) deposits and the seafloor landslides

  5. Influence of Microwaves on the Thermal Conditions of a "Polymer-Semiconductor-Composite" System

    NASA Astrophysics Data System (ADS)

    Kuznetsov, V. G.; Kravchenko, E. V.

    2015-11-01

    A numerical analysis of the influence of microwaves on the thermal conditions of elements of electronic equipment (EE) has been carried out. Investigations have shown that the temperature field of the ″polymer-semiconductor-composite″ system under the action of microwaves is nonuniform. It has been established that under rather typical operating conditions with increasing electric field intensity there is a considerable increase (from 362 to 387 K) in the maximum temperature of the modeled object. Such a strong influence of microwaves on the thermal conditions of the ″polymer-semiconductor-composite″ system is comparable to the increase in the ambient temperature by 20 K or the increase in the heat release of the internal source by 30%.

  6. THE INFLUENCE OF FOLD AND FRACTURE DEVELOPMENT ON RESERVOIR BEHAVIOR OF THE LISBURNE GROUP OF NORTHERN ALASKA

    SciTech Connect

    Wesley K. Wallace; Catherine L. Hanks; Michael T. Whalen; Jerry Jensen; Paul K. Atkinson; Joseph S. Brinton

    2000-05-01

    The Lisburne Group is a major carbonate reservoir unit in northern Alaska. The Lisburne is detachment folded where it is exposed throughout the northeastern Brooks Range, but is relatively undeformed in areas of current production in the subsurface of the North Slope. The objectives of this study are to develop a better understanding of four major aspects of the Lisburne: (1) The geometry and kinematics of detachment folds and their truncation by thrust faults. (2) The influence of folding and lithostratigraphy on fracture patterns. (3) Lithostratigraphy and its influence on folding, faulting, fracturing, and reservoir characteristics. (4) The influence of lithostratigraphy and deformation on fluid flow. The results of field work during the summer of 1999 offer some preliminary insights: The Lisburne Limestone displays a range of symmetrical detachment fold geometries throughout the northeastern Brooks Range. The variation in fold geometry suggests a generalized progression in fold geometry with increasing shortening: Straight-limbed, narrow-crested folds at low shortening, box folds at intermediate shortening, and folds with a large height-to-width ratio and thickened hinges at high shortening. This sequence is interpreted to represent a progressive change in the dominant shortening mechanism from flexural-slip at low shortening to bulk strain at higher shortening. Structural variations in bed thickness occur throughout this progression. Parasitic folding accommodates structural thickening at low shortening and is gradually succeeded by penetrative strain as shortening increases. The amount of structural thickening at low to intermediate shortening may be inversely related to the local amount of structural thickening of the Kayak Shale, the incompetent unit that underlies the Lisburne. The Lisburne Limestone displays a different structural style in the south, across the boundary between the northeastern Brooks Range and the main axis of the Brooks Range fold

  7. The influence of dexamethasone on behaviorally conditioned immunomodulation and plasma corticosterone.

    PubMed

    Kusnecov, A W; Husband, A J; King, M G

    1990-03-01

    Utilizing a conditioned taste aversion paradigm we have previously shown that rats re-exposed to a saccharin solution previously paired with cyclophosphamide (CY) demonstrate significantly reduced in vitro mitogen-induced spleen cell proliferation and IgM secretion assessed 24 h after saccharin re-exposure. In this report treatment of similarly conditioned rats with dexamethasone (DEX) either before conditioning or before re-exposure abrogated the conditioned modulation of pokeweed mitogen (PWM)-induced spleen cell proliferation. The finding that DEX pretreatment on the conditioning day was as effective in abrogating the conditioned response as DEX treatment prior to the test day does not support pituitary-adrenal mediation of the conditioned immusuppressive effect following re-exposure of conditioned animals to the CS. There was no significant conditioned immunosuppression observed with respect to PHA- and Con A-induced proliferation and the influence of DEX on these parameters could not be assessed. The effect on PWM-induced IgM production was inconclusive since the reduced IgM response among conditioned animals was of only borderline significance. PMID:2110491

  8. Catchment and in-stream influences on iron-deposit chemistry, algal-bacterial biomass and invertebrate richness in upland streams, Northern Ireland.

    NASA Astrophysics Data System (ADS)

    Macintosh, Katrina Ann; Griffiths, David

    2013-04-01

    The density and composition of upland stream bed iron-deposits is affected by physical, chemical and biological processes. The basic chemical processes producing ochre deposits are well known. Mobilisation of iron and manganese is influenced by bedrock weathering, the presence of acidic and/or reducing conditions and the concentration of dissolved organic carbon. Ferromanganese-depositing bacteria are significant biogenic agents and can cause/enhance the deposition of metals in streams as (hydr)oxides. Metal concentrations from stream waters in two geological blocks in Northern Ireland were compared to determine the contributions of catchment characteristics and in-stream conditions. One block is composed of metamorphosed schist and unconsolidated glacial drift, with peat or peaty podzol (mainly humic) soils, while the other block consists of tertiary basalt with brown earth and gley soils. Water samples were collected from 52 stream sites and analysed for iron, manganese and aluminium as well as a range of other chemical determinands known to affect metal solubility. Stone deposit material was analysed for metal concentrations, organic matter content and epilithic algae, chlorophyll a concentration. Invertebrates were collected by area-standardised kick samples and animals identified to family and numbers counted. Higher conductivities and concentrations of bicarbonate, alkalinity, calcium and magnesium occurred on basalt than on schist. Despite higher iron and manganese oxide concentrations in basalt-derived non-humic soils, stream water concentrations were much lower and stone deposit concentrations only one third of those occurring on schist overlain by humic soils. Peat-generated acidity and the limited acid neutralising capacity of base-poor metamorphosed schist has resulted in elevated concentrations of metals and ochre deposit in surface waters. Algal biomass was determined by catchment level factors whereas in-stream conditions affected bacterial biomass

  9. Metals, Parasites, and Environmental Conditions Affecting Breeding Populations of Spotted Salamanders (Ambystoma maculatum) in Northern Arkansas, USA.

    PubMed

    DeMali, Heather M; Trauth, Stanley E; Bouldin, Jennifer L

    2016-06-01

    The spotted salamander (Ambystoma maculatum) is indigenous to northern Arkansas, and several breeding sites are known to exist in the region. Spotted salamanders (n = 17) were collected and examined for parasites and only three females harbored nematodes (Physaloptera spp.). Chronic aquatic bioassays were conducted using water collected from eight breeding ponds during different hydroperiod events. No lethal or sublethal effects were measured in Ceriodaphnia dubia; however, decreased growth and survival were seen in Pimephales promelas. Aqueous, sediment, and salamander hepatic samples were analyzed for As, Cd, Cu, Pb, and Ni. Metal analysis revealed possible increased metal exposure following precipitation, with greatest metal concentrations measured in sediment samples. Hepatic metal concentrations were similar in parasitized and non-parasitized individuals, and greatest Pb concentrations were measured following normal precipitation events. Determining environmental stressors of amphibians, especially during their breeding and subsequent larval life stage, is imperative to improve species conservation. PMID:26886425

  10. Influence of Dynamic Hydraulic Conditions on Nitrogen Cycling in Column Experiments

    NASA Astrophysics Data System (ADS)

    Gassen, Niklas; von Netzer, Frederick; Ryabenko, Evgenia; Lüders, Tillmann; Stumpp, Christine

    2015-04-01

    In order to improve management strategies of agricultural nitrogen input, it is of major importance to further understand which factors influence turnover processes within the nitrogen cycle. Many studies have focused on the fate of nitrate in hydrological systems, but up to date only little is known about the influence of dynamic hydraulic conditions on the fate of nitrate at the soil-groundwater interface. We conducted column experiments with natural sediment and compared a system with a fluctuating water table to systems with different water content and static conditions under the constant input of ammonia into the system. We used hydrochemical methods in order to trace nitrogen species, 15N isotope methods to get information about dominating turnover processes and microbial community analysis in order to connect hydrochemical and microbial information. We found that added ammonia was removed more effectively under dynamic hydraulic conditions than under static conditions. Furthermore, denitrification is the dominant process under saturated, static conditions, while nitrification is more important under unsaturated, static conditions. We conclude that a fluctuating water table creates hot spots where both nitrification and denitrification processes can occur spatially close to each other and therefore remove nitrogen more effectively from the system. Furthermore, the fluctuating water table enhances the exchange of solutes and triggers hot moments of solute turnover. Therefore we conclude that a fluctuating water table can amplify hot spots and trigger hot moments of nitrogen cycling.

  11. Body size and condition influence migration timing of juvenile Arctic grayling

    USGS Publications Warehouse

    Heim, Kurt C.; Wipfli, Mark S.; Whitman, Matthew S.; Seitz, Andrew C

    2016-01-01

    Freshwater fishes utilising seasonally available habitats within annual migratory circuits time movements out of such habitats with changing hydrology, although individual attributes of fish may also mediate the behavioural response to environmental conditions. We tagged juvenile Arctic grayling in a seasonally flowing stream on the Arctic Coastal Plain in Alaska and recorded migration timing towards overwintering habitat. We examined the relationship between individual migration date, and fork length (FL) and body condition index (BCI) for fish tagged in June, July and August in three separate models. Larger fish migrated earlier; however, only the August model suggested a significant relationship with BCI. In this model, 42% of variability in migration timing was explained by FL and BCI, and fish in better condition were predicted to migrate earlier than those in poor condition. Here, the majority (33%) of variability was captured by FL with an additional 9% attributable to BCI. We also noted strong seasonal trends in BCI reflecting overwinter mass loss and subsequent growth within the study area. These results are interpreted in the context of size and energetic state-specific risks of overwinter starvation and mortality (which can be very high in the Arctic), which may influence individuals at greater risk to extend summer foraging in a risky, yet prey rich, habitat. Our research provides further evidence that heterogeneity among individuals within a population can influence migratory behaviour and identifies potential risks to late season migrants in Arctic beaded stream habitats influenced by climate change and petroleum development.

  12. The influence of Ryukyu subduction on magma genesis in the Northern Taiwan Volcanic Zone and Middle Okinawa Trough - Evidence from boron isotopes

    NASA Astrophysics Data System (ADS)

    Pi, Ju-Lien; You, Chen-Feng; Wang, Kuo-Lung

    2016-09-01

    Boron (B) is an excellent geochemical tracer for investigating crustal recycling processes at convergent margins, due to its high fluid mobility under high P-T conditions, distinct elemental abundances and isotopic compositions in the mantle wedge and subducting slabs. The Northern Taiwan Volcanic Zone (NTVZ), wherein the nature of magma genesis has long been a topic of debate, is located at the rear side of the Okinawa Trough (OT), an atypical back-arc rift in the Ryukyu subduction system. In this study, B and B isotopes (δ11B) were measured in 19 volcanic rocks collected from the NTVZ and the middle Okinawa Trough (MOT) to assess the influence of the Ryukyu subduction system on magma genesis. The B concentrations in the MOT and NTVZ volcanic rocks are 5.8 to 13.6 mg/L and 2.2 to 48.6 mg/L, respectively. The large B abundances variation in the NTVZ was caused mainly by variable degrees of partial melting. The Nb/B and δ11B in the MOT have small ranges of 0.5 to 0.6 and - 2.7‰ to 0.2‰, respectively, whereas they range widely from 0.4 to 2.5 and from - 8.6‰ to 2.4‰, respectively in the NTVZ. These Nb/B values suggest that the magma contains a smaller subduction component than that normally observed in arcs, although this component is still more substantial than in a typical back-arc setting. The δ11B results indicate insignificant influence of the subducting Philippine Sea Plate at 2.6 Ma, but it becomes more substantial later in the NTVZ. The mixing proportions of sediment derived fluids in onshore volcanoes in the NTVZ imply a rather heterogeneous mantle wedge near the plate boundary, most likely due to either a heterogeneous source of slab derived fluids or more complicated mantle flow. A substantial B flux from the subducting slab in the incipient back-arc rifting in the MOT and NTVZ may reflect characteristics of a cold, steep and fast subducting slab, which may be capable of carrying volatiles efficiently into greater depth in subduction zones. The

  13. Influence of sound-conditioning on noise-induced susceptibility of distortion-product otoacoustic emissions.

    PubMed

    Luebke, Anne E; Stagner, Barden B; Martin, Glen K; Lonsbury-Martin, Brenda L

    2015-07-01

    Cochlear damage caused by loud sounds can be attenuated by "sound-conditioning" methods. The amount of adaptation for distortion product otoacoustic emissions (DPOAEs) measured in alert rabbits previously predicted an ear's susceptibility to a subsequent noise exposure. The present study investigated if sound-conditioning influenced the robustness of such DPOAE adaptation, and if such conditioning elicited more protection by increasing the amount of DPOAE adaptation. Toward this end, rabbits were divided into two study groups: (1) experimental animals exposed to a sound-conditioning protocol, and (2) unconditioned control animals. After base-line measures, all rabbits were exposed to an overstimulation paradigm consisting of an octave band noise, and then re-assessed 3 weeks post-exposure to determine permanent changes in DPOAEs. A major result was that prior sound-conditioning protected reductions in DPOAE levels by an average of 10-15 dB. However, DPOAE adaptation decreased with sound-conditioning, so that such conditioning was no longer related to noise-induced reductions in DPOAEs. Together, these findings suggest that sound-conditioning affected neural pathways other than those that likely mediate DPOAE adaptation (e.g., medial olivocochlear efferent and/or middle-ear muscle reflexes). PMID:26233006

  14. Influence of ENSO and the NAO on terrestrial carbon uptake in the Texas-northern Mexico region

    NASA Astrophysics Data System (ADS)

    Parazoo, Nicholas C.; Barnes, Elizabeth; Worden, John; Harper, Anna B.; Bowman, Kevin B.; Frankenberg, Christian; Wolf, Sebastian; Litvak, Marcy; Keenan, Trevor F.

    2015-08-01

    Climate extremes such as drought and heat waves can cause substantial reductions in terrestrial carbon uptake. Advancing projections of the carbon uptake response to future climate extremes depends on (1) identifying mechanistic links between the carbon cycle and atmospheric drivers, (2) detecting and attributing uptake changes, and (3) evaluating models of land response and atmospheric forcing. Here, we combine model simulations, remote sensing products, and ground observations to investigate the impact of climate variability on carbon uptake in the Texas-northern Mexico region. Specifically, we (1) examine the relationship between drought, carbon uptake, and variability of El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) using the Joint UK Land-Environment Simulator (JULES) biosphere simulations from 1950-2012, (2) quantify changes in carbon uptake during record drought conditions in 2011, and (3) evaluate JULES carbon uptake and soil moisture in 2011 using observations from remote sensing and a network of flux towers in the region. Long-term simulations reveal systematic decreases in regional-scale carbon uptake during negative phases of ENSO and NAO, including amplified reductions of gross primary production (GPP) (-0.42 ± 0.18 Pg C yr-1) and net ecosystem production (NEP) (-0.14 ± 0.11 Pg C yr-1) during strong La Niña years. The 2011 megadrought caused some of the largest declines of GPP (-0.50 Pg C yr-1) and NEP (-0.23 Pg C yr-1) in our simulations. In 2011, consistent declines were found in observations, including high correlation of GPP and surface soil moisture (r = 0.82 ± 0.23, p = 0.012) in remote sensing-based products. These results suggest a large-scale response of carbon uptake to ENSO and NAO, and highlight a need to improve model predictions of ENSO and NAO in order to improve predictions of future impacts on the carbon cycle and the associated feedbacks to climate change.

  15. Influence of water temperature and salinity on Vibrio vulnificus in Northern Gulf and Atlantic Coast oysters (Crassostrea virginica).

    PubMed

    Motes, M L; DePaola, A; Cook, D W; Veazey, J E; Hunsucker, J C; Garthright, W E; Blodgett, R J; Chirtel, S J

    1998-04-01

    This study investigated the temperature and salinity parameters associated with waters and oysters linked to food-borne Vibrio vulnificus infections. V. vulnificus was enumerated in oysters collected at three northern Gulf Coast sites and two Atlantic Coast sites from July 1994 through September 1995. Two of these sites, Black Bay, La., and Apalachicola Bay, Fla., are the source of the majority of the oysters implicated in V. vulnificus cases. Oysters in all Gulf Coast sites exhibited a similar seasonal distribution of V. vulnificus: a consistently large number (median concentration, 2,300 organisms [most probable number] per g of oyster meat) from May through October followed by a gradual reduction during November and December to < or = 10 per g, where it remained from January through mid-March, and a sharp increase in late March and April to summer levels. V. vulnificus was undetectable (< 3 per g) in oysters from the North and South Carolina sites for most of the year. An exception occurred when a late-summer flood caused a drop in salinity in the North Carolina estuary, apparently causing V. vulnificus numbers to increase briefly to Gulf Coast levels. At Gulf Coast sites, V. vulnificus numbers increased with water temperatures up to 26 degrees C and were constant at higher temperatures. High V. vulnificus levels (> 10(3) per g) were typically found in oysters from intermediate salinities (5 to 25 ppt). Smaller V. vulnificus numbers (< 10(2) per g) were found at salinities above 28 ppt, typical of Atlantic Coast sites. On 11 occasions oysters were sampled at times and locations near the source of oysters implicated in 13 V. vulnificus cases; the V. vulnificus levels and environmental parameters associated with these samples were consistent with those of other study samples collected from the Gulf Coast from April through November. These findings suggest that the hazard of V. vulnificus infection is not limited to brief periods of unusual abundance of V

  16. Influence of the slip conditions on the stress corrosion cracking microprocesses in fcc materials

    SciTech Connect

    Chambreuil-Paret, A.; Chateau, J.P.; Magnin, T.

    1997-11-01

    The aim of the present paper is to carefully analyze the stress corrosion cracking (SCC) microprocesses of f.c.c. single crystals, not only for the influence of the tensile axis orientation but also for the influence of the cracking direction (imposed or not). 316L (in MgCl{sub 2}) and copper (in nitrites) single crystals of well defined tensile axis will be strained using the slow strain rate technique. The authors focus on the influence of the relative orientations of the cracking direction and the slip planes on the crystallography of fracture. The effect of slip conditions on the corrosion-deformation interactions leading to fracture are then emphasized, which gives major information relevant to the micromodelling of SCC.

  17. Topological quantum scattering under the influence of a nontrivial boundary condition

    NASA Astrophysics Data System (ADS)

    Mota, Herondy

    2016-04-01

    We consider the quantum scattering problem of a relativistic particle in (2 + 1)-dimensional cosmic string spacetime under the influence of a nontrivial boundary condition imposed on the solution of the Klein-Gordon equation. The solution is then shifted as consequence of the nontrivial boundary condition and the role of the phase shift is to produce an Aharonov-Bohm-like effect. We examine the connection between this phase shift and the electromagnetic and gravitational analogous of the Aharonov-Bohm effect and compare the present results with previous ones obtained in the literature, also considering non-relativistic cases.

  18. Genotypic influence on aversive conditioning in honeybees, using a novel thermal reinforcement procedure.

    PubMed

    Junca, Pierre; Carcaud, Julie; Moulin, Sibyle; Garnery, Lionel; Sandoz, Jean-Christophe

    2014-01-01

    In Pavlovian conditioning, animals learn to associate initially neutral stimuli with positive or negative outcomes, leading to appetitive and aversive learning respectively. The honeybee (Apis mellifera) is a prominent invertebrate model for studying both versions of olfactory learning and for unraveling the influence of genotype. As a queen bee mates with about 15 males, her worker offspring belong to as many, genetically-different patrilines. While the genetic dependency of appetitive learning is well established in bees, it is not the case for aversive learning, as a robust protocol was only developed recently. In the original conditioning of the sting extension response (SER), bees learn to associate an odor (conditioned stimulus - CS) with an electric shock (unconditioned stimulus - US). This US is however not a natural stimulus for bees, which may represent a potential caveat for dissecting the genetics underlying aversive learning. We thus first tested heat as a potential new US for SER conditioning. We show that thermal stimulation of several sensory structures on the bee's body triggers the SER, in a temperature-dependent manner. Moreover, heat applied to the antennae, mouthparts or legs is an efficient US for SER conditioning. Then, using microsatellite analysis, we analyzed heat sensitivity and aversive learning performances in ten worker patrilines issued from a naturally inseminated queen. We demonstrate a strong influence of genotype on aversive learning, possibly indicating the existence of a genetic determinism of this capacity. Such determinism could be instrumental for efficient task partitioning within the hive. PMID:24828422

  19. Genotypic Influence on Aversive Conditioning in Honeybees, Using a Novel Thermal Reinforcement Procedure

    PubMed Central

    Junca, Pierre; Carcaud, Julie; Moulin, Sibyle; Garnery, Lionel; Sandoz, Jean-Christophe

    2014-01-01

    In Pavlovian conditioning, animals learn to associate initially neutral stimuli with positive or negative outcomes, leading to appetitive and aversive learning respectively. The honeybee (Apis mellifera) is a prominent invertebrate model for studying both versions of olfactory learning and for unraveling the influence of genotype. As a queen bee mates with about 15 males, her worker offspring belong to as many, genetically-different patrilines. While the genetic dependency of appetitive learning is well established in bees, it is not the case for aversive learning, as a robust protocol was only developed recently. In the original conditioning of the sting extension response (SER), bees learn to associate an odor (conditioned stimulus - CS) with an electric shock (unconditioned stimulus - US). This US is however not a natural stimulus for bees, which may represent a potential caveat for dissecting the genetics underlying aversive learning. We thus first tested heat as a potential new US for SER conditioning. We show that thermal stimulation of several sensory structures on the bee’s body triggers the SER, in a temperature-dependent manner. Moreover, heat applied to the antennae, mouthparts or legs is an efficient US for SER conditioning. Then, using microsatellite analysis, we analyzed heat sensitivity and aversive learning performances in ten worker patrilines issued from a naturally inseminated queen. We demonstrate a strong influence of genotype on aversive learning, possibly indicating the existence of a genetic determinism of this capacity. Such determinism could be instrumental for efficient task partitioning within the hive. PMID:24828422

  20. Influence of temper condition on the nonlinear stress-strain behavior of boron-aluminum

    NASA Technical Reports Server (NTRS)

    Kennedy, J. M.; Herakovich, E. T.; Tenney, D. R.

    1977-01-01

    The influence of temper condition on the tensile and compressive stress-strain behavior for six boron-aluminum laminates was investigated. In addition to monotonic tension and compression tests, tension-tension, compression-compression, and tension--compression tests were conducted to study the effects of cyclic loading. Tensile strength results are a function of the laminate configuration; unidirectional laminates were affected considerably more than other laminates with some strength values increasing and others decreasing.

  1. Discharge conditions in Hall thrusters: secondary electrons emission yield and magnetic mirror influence

    NASA Astrophysics Data System (ADS)

    Miedzik, J.; Daniłko, D.

    2014-11-01

    One dimensional model of plasma bound by two nonconducting walls in external magnetic and electric field is developed. In particular it is designed to describe plasma in Hall thrusters. Combination of Particle-in-cell method with guiding centre approximation of electrons motion allows for kinetic description in short computational time. Comparison of plasma parameters done for two different secondary electrons emission profiles reveals insignificant influence of wall material on the condition in one dimensional model.

  2. Complex influence of space environment on materials and electronic devices in the conditions of microgravity

    NASA Astrophysics Data System (ADS)

    Musabayev, T.; Zhantayev, Zh.; Grichshenko, V.

    2016-09-01

    The paper presents a new physical model describing the processes in materials and electronic devices under the influence of cosmic rays in microgravity. The model identifies specific features of formation of the area of radiation defects (ARD) in the electronic materials in microgravity. The mechanism of interaction between the ARD and memory modules in microgravity causing malfunction and failure of onboard electronics is considered. The results of failure of memory modules under real conditions are presented.

  3. SAND FLUX IN THE NORTHERN CHIHUAHUAN DESERT, NEW MEXICO, USA, AND THE INFLUENCE OF MESQUITE-DOMINATED LANDSCAPES

    EPA Science Inventory

    This study was designed to test two hypotheses: (1) that land dominated by mesquite (Prosopis glandulosa) is the most important area for active sand movement at the Jornada Experimental Range, located in the northern part of the Chihuahuan desert, and (2) that the most active san...

  4. Circulation in the French mediterranean coastal zone near Marseilles: the influence of wind and the Northern Current

    NASA Astrophysics Data System (ADS)

    Albérola, C.; Millot, C.

    2003-04-01

    Current meters were moored for a year both in and beyond the Cassis Bay to study the dispersion of muds discharged at a depth of ˜300 m, through a pipe, a few km from the coast and at the head of a submarine canyon. The east-west orientation of the coastline and a marked orography constrain the major winds to easterlies or westerlies. Empirical orthogonal function analysis shows that both wind regimes create a significant down-wind circulation, with the latter inducing also intense upwelling. Characteristics of the Northern Current, which flows along the slope, have been defined using a fine-grid hydrological survey. A narrow continental shelf allows the Northern Current to reach often the coastal zone in the study area; thus, the overall water circulation in the embayment is westward. In winter, this current develops steep mesoscale meanders and penetrates easily through the canyon, into the bay. Hence, although the coastal circulation near Marseilles is partly down-wind, it is dependent mainly on the Northern Current (on both general and meso-scales). The mesoscale variability cannot be predicted without monitoring the Northern Current itself.

  5. Circulation in the French Mediterranean coastal zone near Marseilles: the influence of wind and the Northern Current

    NASA Astrophysics Data System (ADS)

    Albérola, C.; Millot, C.

    2003-04-01

    Current meters were moored for a year both in and beyond the Cassis Bay to study the dispersion of muds discharged at a depth of about 300 m, through a pipe, a few km from the coast and at the head of a submarine canyon. The east-west orientation of the coastline and a marked orography constrain the major winds to easterlies or westerlies. Empirical orthogonal function (EOF) analysis shows that both wind regimes create a significant down-wind circulation, with the latter inducing also intense upwelling. Characteristics of the Northern Current, which flows along the slope, have been defined using a fine-grid hydrological survey. A narrow continental shelf allows the Northern Current to reach often the coastal zone in the study area; thus, the overall water circulation in the embayment is westward. In winter, this current develops steep mesoscale meanders and penetrates easily through the canyon, into the bay. Hence, although the coastal circulation near Marseilles is partly down-wind, it is dependent mainly on the Northern Current (on both general and meso- scales). The mesoscale variability cannot be predicted without monitoring the Northern Current itself.

  6. The influence of different El Nino types on the northern hemisphere stratosphere simulated by the MPI-ESM

    NASA Astrophysics Data System (ADS)

    Bittner, Matthias; Timmreck, Claudia; Schmidt, Hauke

    2013-04-01

    It is known that the El Nino Southern Oscillation (ENSO), although it is mainly a tropospheric phenomenon, has an impact on the polar winter stratosphere [e.g. van Loon and Labitzke, 1987: Camp and Tung, 2007]. This has also been shown in simulations with general circulation models (GCM) [Sassi,et al. 2004, Manzini et al. 2006]. For a couple of years there are discussions about two different "flavors" of the the El Nino, the central Pacific (or Modoki) El Nino and the east Pacific El Nino [e.g. Wang and Weisberg, 2000; Yu and Kao, 2007; Ashok et al. 2007]. An observational study [Graf and Zanchettin, 2012] indicate that the polar vortex is more disturbed during EP El Ninos. Here we to investigate the influence of the equatorial sea surface temperatures on the stratosphere-troposphere coupling in the northern hemisphere winter season in a fully coupled atmosphere-ocean-land GCM. We use two versions of the Max-Planck-Institute for Meteorology model MPI-ESM, namely MPI-ESM-LR with lower T63 L47 atmosphere and GR15 ocean resolution and the MPI-ESM-MR with the same horizontal resolution in the atmosphere but a higher resolution in the vertical (L95) and in the ocean (TP04). To exclude effects of natural and anthropogenic forcing, we analyze a 1000 year coupled control simulation with pre-industrial greenhouse gas concentration and constant solar forcing (piControl). For comparison with reananlyis data we also analyze uncoupled atmosphere-only simulations with observed sea surface temperatures from 1979 until 2008 (AMIP). We compare three ways of defining El Nino: the central Pacific (CP), the east Pacific (EP) and the canonical Nino3.4 El Nino. We show to what extent the MPI-ESM is able to simulate these different types of El Nino and how they affect the polar stratosphere. The MPI-ESM model is in both versions capable of producing CP and EP El Ninos. However, the CP El Nino is dominant one in terms of magnitude and the EP El Nino has a relative small impact on global

  7. Influence of industrial processing on orange juice flavanone solubility and transformation to chalcones under gastrointestinal conditions.

    PubMed

    Gil-Izquierdo, Angel; Gil, María Isabel; Tomas-Barberan, Francisco Abraham; Ferreres, Federico

    2003-05-01

    Orange juice manufactured at industrial scale was subjected to digestion under in vitro gastrointestinal conditions (pH, temperature, and enzyme and chemical conditions) to evaluate the influence of individual industrial processing treatments on flavanone solubility, stability, and ability to permeate through a membrane under simulated physiological conditions. Four industrial processes including squeezing, standard pasteurization, concentration, and freezing were evaluated. Hand squeezing was compared with industrial squeezing. After in vitro gastrointestinal digestion of the orange juices, the flavanones able to permeate through a dialysis membrane, and those remaining in the retentate were evaluated by HPLC as were those present in the insoluble fraction. In all of the assayed orange juices, a high content of precipitated chalcones ( approximately 70% of the total flavanones) was formed under the physiological conditions of the gastrointestinal tract. Hand squeezing provided a higher concentration of flavanones in the permeated fraction and lower transformation to chalcones than industrial squeezing. Standard pasteurization did not influence the solubility and permeability of the orange juice flavanones and chalcones. Industrial concentration did not affect the amount of flavanones able to permeate but decreased the chalcones produced. Juices produced from frozen orange juice contained considerably smaller amounts of both soluble flavanones and insoluble chalcones. PMID:12720386

  8. The influence of gonadal hormones on conditioned fear extinction in healthy humans.

    PubMed

    Milad, M R; Zeidan, M A; Contero, A; Pitman, R K; Klibanski, A; Rauch, S L; Goldstein, J M

    2010-07-14

    Recent rodent studies suggest that gonadal hormones influence extinction of conditioned fear. Here we investigated sex differences in, and the influence of estradiol and progesterone on, fear extinction in healthy humans. Men and women underwent a two-day paradigm in which fear conditioning and extinction learning took place on day 1 and extinction recall was tested on day 2. Visual cues were used as the conditioned stimuli and a mild electric shock was used as the unconditioned stimulus. Skin conductance was recorded throughout the experiment and used to measure conditioned responses (CRs). Blood samples were obtained from all women to measure estradiol and progesterone levels. We found that higher estradiol during extinction learning enhanced subsequent extinction recall but had no effects on fear acquisition or extinction learning itself. Sex differences were only observed during acquisition, with men exhibiting significantly higher CRs. After dividing women into low- and high-estradiol groups, men showed comparable extinction recall to high-estradiol women, and both of these groups showed higher extinction recall than low-estradiol women. Therefore, sex differences in extinction memory emerged only after taking into account women's estradiol levels. Lower estradiol may impair extinction consolidation in women. These findings could have practical applications in the treatment of anxiety disorders through cognitive and behavioral therapies. PMID:20412837

  9. The influence of gonadal hormones on conditioned fear extinction in healthy humans

    PubMed Central

    Milad, Mohammed R; Zeidan, Mohamed A.; Contero, Angelica; Pitman, Roger K.; Klibanski, Anne; Rauch, Scott L.; Goldstein, Jill M.

    2010-01-01

    Recent rodent studies suggest that gonadal hormones influence extinction of conditioned fear. Here we investigated sex differences in, and the influence of estradiol and progesterone on, fear extinction in healthy humans. Men and women underwent a two-day paradigm in which fear conditioning and extinction learning took place on day 1 and extinction recall was tested on day 2. Visual cues were used as the conditioned stimuli and a mild electric shock was used as the unconditioned stimulus. Skin conductance was recorded throughout the experiment and used to measure conditioned responses (CRs). Blood samples were obtained from all women to measure estradiol and progesterone levels. We found that higher estradiol during extinction learning enhanced subsequent extinction recall but had no effects on fear acquisition or extinction learning itself. Sex differences were only observed during acquisition, with men exhibiting significantly higher CRs. After dividing women into low- and high-estradiol groups, men showed comparable extinction recall to high-estradiol women, and both of these groups showed higher extinction recall than low-estradiol women. Therefore, sex differences in extinction memory emerged only after taking into account women's estradiol levels. Lower estradiol may impair extinction consolidation in women. These findings could have practical applications in the treatment of anxiety disorders through cognitive and behavioral therapies. PMID:20412837

  10. Longevity of White Clover (Trifolium repens) Leaves, Stolons and Roots, and Consequences for Nitrogen Dynamics under Northern Temperate Climatic Conditions

    PubMed Central

    Sturite, Ievina; Henriksen, Trond Maukon; Breland, Tor Arvid

    2007-01-01

    Background and Aims White clover (Trifolium repens) is, due to nitrogen (N) fixation, important to the N dynamics of several northern temperate agroecosystems. This study aimed at monitoring growth and death of major white clover plant organs to assess their potential contribution to within-season N input and risk of off-season N losses. Methods White clover (‘Snowy’) was studied in a plot and root window experiment in southeast Norway (60°42′N, 10°51′E). Leaves, stolons and roots were tagged for lifespan measurement in harvested and unharvested stands during two experimental years. The availability of soil inorganic N was measured by plant root simulator (PRS™) probes. Key Results The longevity of leaves and petioles ranged from 21 to 86 d (mean = 59 d), of main stolon sections from 111 to over 677 d (mean = 411 d) and of roots from 27 to 621 d (mean = 290 d). About 60 % of the leaves produced had turned over by the end of the growing season and another 30 % had died or disappeared by the subsequent spring. Harvesting reduced the longevity of stolons and increased plant fragmentation, but did not decrease leaf or root lifespan or increase soil N availability. From the plant organ turnover data, it was estimated that the gross N input to the soil–plant system from white clover in pure stand during two growing seasons corresponded to a 2·5-fold increase over the total N in harvestable shoots. Conclusions The short lifespan and poor over-wintering of leaves showed their potential importance as a nitrogen source in the soil–plant ecosystem but also their potential contribution to the risk of off-season N losses. PMID:17495980