bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of climate, water content and leaching on seasonal variations in potential water repellence
Authors: Hardie Marcus A. , Cotching William E. , Doyle Richard B. , Lisson Shaun 
Published: September 2011

AbstractSeasonal variation in potential water repellence has not been widely reported in the literature, and little is known of the processes that cause changes in potential water repellence. In this study, the severity and stability of potential water repellence varied seasonally from being weakly hydrophobic in July 2009 (water drop penetration time, 0.19 min; water entry potential, 0.0 cm) to severely hydrophobic (water drop penetration time, 54 min; water entry potential, 14.3 cm) in May 2009. Seasonal variation in the stability of potential water repellence was significantly correlated with cumulative rainfall, air temperature and soil water deficit, which indicated that the accumulation of water‐repellent compounds, presumably polar waxes, resulted from microbial or plant inputs to the soil. Laboratory experiments demonstrated that saturating and mixing the soil resulted in a two to three order of magnitude reduction in the stability of potential water repellence, even after oven drying at 40 °C and 60 °C. Repeated leaching resulted in sequential reduction in both the stability and severity of water repellence. The significant correlation between soil water repellence and dissolved organic carbon content of the leachate, together with pedological evidence of organic staining of ped faces in the clay subsoil indicate that seasonal rainfall leached soluble water‐repellent compounds from the topsoil. The reestablishment of water repellence after saturation and leaching required the input of new water‐repellent compounds. These findings suggest that the use of surfactants before sowing may assist to leach water‐repellent compounds from the topsoil, allowing improved infiltration and reduced runoff through the remainder of the cropping season. Copyright © 2011 John Wiley & Sons, Ltd.
Ecohydrological evolution model on riparian vegetation in hyperarid regions and its validation in the lower reach of Tarim River
Authors: Liu Dengfeng , Tian Fuqiang , Hu Heping , Lin Mu , Cong Zhentao 
Published: September 2011

AbstractThe evolution of the ecohydrological system driven by external climatic forcing and internal feedbacks between vegetation and hydrology, which is more remarkable in arid and semiarid regions, has attracted substantial research attention in recent years. To examine critically the state‐of‐the‐art assumptions and dynamic equations used in the evolution study of an ecohydrological system, the rule of proceeding from simplicity to complexity should be followed. The riparian vegetation ecohydrological system in hyperarid regions (e.g. the lower Tarim River) can serve as a starting point given its simplicity, which has been seldom examined before in terms of system evolution. Further, the water transfer practice from 2000 to 2006 in the lower Tarim River serves as a valuable prototype experiment for model validation. This is because the remarkable changes in groundwater and vegetation in the area have taken place within a shorter period and thus can be easily observed. In the present study, the ecohydrological evolution model on riparian vegetation (ERV model) in hyperarid regions was proposed by coupling groundwater movement and vegetation dynamics. In the ERV model, the groundwater table serves as a critical feedback variable that determines the vegetation dynamics (colonization and mortality) and is determined by vegetation transpiration other than groundwater movement. The monitored groundwater table by wells and satellite‐observed vegetation coverage from the Moderate Resolution Imaging Spectroradiometer are used for model validation. The simulation results show the good performance of the ERV model with uncalibrated parameters. It was also calibrated manually using a multiobjective method, and the fine‐tuned parameters are close to the uncalibrated ones, indicating the robustness of the model. The analysis shows further that the increased evapotranspiration is substantially due to the water transfer and thus the vegetation growth, which implies the importance of ecohydrological coupling for long‐term hydrological modelling. Copyright © 2011 John Wiley & Sons, Ltd.
Water storage at the Panola Mountain Research Watershed, Georgia, USA
Authors: Peters Norman E. , Aulenbach Brent T. 
Published: September 2011

AbstractStorage is a major component of a catchment water balance particularly when the water balance components are evaluated on short time scales, that is, less than annual. We propose a method of determining the storage–discharge relation using an exponential function and daily precipitation, potential evapotranspiration (PET) and baseflow during the dormant season when evapotranspiration (ET) is low. The method was applied to the 22‐year data series of the 0.41‐ha forested Panola Mountain Research Watershed, Georgia. The relation of cumulative daily precipitation minus daily runoff and PET versus baseflow was highly significant (r2 = 0.92, p < 0.0001), but the initial storage for each year varied markedly. For the 22‐year study period, annual precipitation and runoff averaged 1240 and 380 mm, respectively, whereas the absolute catchment storage range was ~400 mm, averaging 219 mm annually, which is attributed to contributions of soil water and groundwater. The soil moisture of a catchment average 1‐m soil depth was evaluated and suggests that there was an active (changes in soil storage during stormflow) and passive (a longer‐term seasonal cycle) soil water storage with ranges of 40–70 and 100–120 mm, respectively. The active soil water storage was short term on the order of days during and immediately after rainstorms, and the passive or seasonal soil storage was highest during winter when ET was lowest and lowest during summer when ET was highest. An estimate of ET from daily changes in soil moisture (ETSM) during recessions was comparable with PET during the dormant season (1.5 mm day−1) but was much lower during the growing season (June through August); monthly average SMET and PET ranged from 2.8 to 4.0 mm day−1 and from 4.5 to 5.5 mm day−1, respectively. The growing season difference is attributed to the overestimation of PET. ETSM estimates were comparable with those derived from hillslope water balances during sprinkling experiments. Master recession curves derived from the storage–discharge relation adjusted seasonally for ET (1.5 and 4.0 mm day−1 during the dormant and growing seasons, respectively) fit actual recessions extremely well. Copyright © 2011 John Wiley & Sons, Ltd.
Hydrochemical and sedimentary responses of paired High Arctic watersheds to unusual climate and permafrost disturbance, Cape Bounty, Melville Island, Canada
Authors: Lewis Ted , Lafrenière Melissa J. , Lamoureux Scott F. 
Published: September 2011

AbstractHigh Arctic river responses to changing hydroclimatic and landscape processes are poorly understood. In non‐glacierized basins, snowmelt and rainfall generate river discharge, which provides first order control over fluxes. Further factors include the seasonality of precipitation, seasonal active layer development, and permafrost disturbance. These controls were evaluated in terms of sedimentary and biogeochemical fluxes from paired catchments at Cape Bounty, Melville Island, Nunavut during 2006–2009. Results indicate that the source of runoff can be more important than the amount of runoff for sediment, solutes, and organic yields. Although the snowmelt period is typically the most important time for these yields, heavy late summer precipitation events can create disproportionately large yields. Rainfall increases yields because it hydrologically connects areas otherwise isolated. Inorganic solute yields from late summer rainfall are higher because the thick active layer maximizes hydrologic interactions with mineral soils and generates high solute concentrations. Results also indicate that while the catchments are broadly similar, subtle topographic differences result in important inter‐catchment differences in runoff and suspended and dissolved loads. The East watershed, which had less extensive permafrost disturbance, consistently had higher concentrations of dissolved solids. These higher dissolved fluxes cannot therefore be explained by thermokarst features, but rather by deeper active layer development, due to a greater proportion of south‐facing slopes. Although warm temperatures in 2007 led to extensive active layer disturbance in the West watershed, because the disturbances were largely hydrologically disconnected, the total disturbed area was small, and inter‐annual variability in discharge was high, there was no detectable response in dissolved loads to disturbances. Sediment availability increased after 2007, but yields have largely returned to pre‐disturbance levels. Results indicate that seasonality and frequency‐magnitude characteristics of projected increases in precipitation must be considered along with active layer changes to predict the fluvial sedimentary and biogeochemical response to regional climate change. Copyright © 2011 John Wiley & Sons, Ltd.
Impact of artificial subsurface drainage on groundwater travel times and baseflow discharge in an agricultural watershed, Iowa (USA)
Authors: Schilling Keith E. , Jindal Priyanka , Basu Nandita B. , Helmers Matthew J. 
Published: September 2011

AbstractPollutant delivery through artificial subsurface drainage networks to streams is an important transport mechanism, yet the impact of drainage tiles on groundwater hydrology at the watershed scale has not been well documented. In this study, we developed a two‐dimensional, steady‐state groundwater flow model for a representative Iowa agricultural watershed to simulate the impact of tile drainage density and incision depth on groundwater travel times and proportion of baseflow contributed by tile drains. Varying tile drainage density from 0 to 0.0038 m−1, while maintaining a constant tile incision depth at 1.2 m, resulted in the mean groundwater travel time to decrease exponentially from 40 years to 19 years and increased the tile contribution to baseflow from 0% to an upper bound of 37%. In contrast, varying tile depths from 0.3 to 2.7 m, while maintaining a constant tile drainage density of 0.0038 m−1, caused mean travel times to decrease linearly from 22 to 18 years and increased the tile contribution to baseflow from 30% to 54% in a near‐linear manner. The decrease in the mean travel time was attributed to decrease in the saturated thickness of the aquifer with increasing drainage density and incision depth. Study results indicate that tile drainage affects fundamental watershed characteristics and should be taken into consideration when evaluating water and nitrate export from agricultural regions. Copyright © 2011 John Wiley & Sons, Ltd.
Ovarian cancer risk factors by histologic subtypes in the NIH‐AARP diet and health study
Authors: Yang Hannah P. , Trabert Britton , Murphy Megan A. , Sherman Mark E. , Sampson Joshua N. , Brinton Louise A. , Hartge Patricia , Hollenbeck Albert , Park Yikyung , Wentzensen Nicolas 
Published: September 2011

AbstractData suggest that risk factors for ovarian carcinoma vary by histologic type, but findings are inconsistent. We prospectively evaluated risk factors by histological subtypes of incident ovarian cancer (n = 849) in a cohort of 169,391 women in the NIH‐AARP Diet and Health Study. We constructed Cox models of individual exposures by comparing case subtypes to the entire non‐case group and assessed p‐heterogeneity in case–case comparisons using serous as the reference category. Substantial risk differences between histologic subtypes were observed for menopausal hormone therapy (MHT) use, oral contraceptive (OC) use, parity and body mass index (p‐heterogeneity = 0.01, 0.03, 0.05, 0.03, respectively). MHT users were at increased risk for all histologic subtypes except for mucinous carcinomas, where risk was reduced (relative risk (RR) = 0.37; 95% confidence interval (CI): 0.18, 0.80). OC users were only at significantly decreased risk for serous cancers (RR = 0.69; 95% CI: 0.55, 0.85). Although parity was inversely associated with risk of all subtypes, the RRs ranged from 0.28 (clear cell) to 0.83 (serous). Obesity was a significant risk factor only for endometrioid cancers (RR = 1.64; 95% CI: 1.00, 2.70). Our findings support a link between etiological factors and histological heterogeneity in ovarian carcinoma.
Surface ultrastructure of the gill filaments and the secondary lamellae of the catfish,Rita rita, and the carp, Cirrhinus mrigala
Authors: Kumari Usha , Mittal Swati , Mittal Ajay Kumar 
Published: September 2011

AbstractSurface ultrastructures of gill filaments and secondary lamellae of Rita rita and Cirrhinus mrigala, inhabiting different ecological habitat, were investigated to unravel adaptive modifications. R. rita is a sluggish, bottom dwelling carnivorous catfish, which inhabits regions of river with accumulations of dirty water. It retains its viability for long time if taken out of water. C. mrigala is an active bottom dwelling Indian major carp, which lives in relatively clean water and dies shortly after taken out of water. In R. rita, gill septa between gill filaments are reduced. Microridges on epithelial cells covering gill filaments are often continuous and arranged concentrically. Secondary lamellae are extensive. The epithelium appears corrugated, show irregular elevations and shallow depressions, and microridges on epithelial cells appear fragmented. In C. mrigala, in contrast, the gill septa are extensive. Microridges on epithelial cells covering gill filaments are fragmented. Secondary lamellae are less extensive. The epithelium appears smooth and microridges on epithelial cells are relatively inconspicuous. These differences have been considered adaptive modification in relation to habit and ecological niches inhabited by two fish species. Presence of mucous goblet cells on gill filaments is discussed in relation to their functions including precipitation of the sediments and preventing clogging of gill filaments. Infrequent mucous goblet cells in the epithelium of secondary lamellae in two fish species are considered an adaptation, minimizing thickness of the epithelium to reduce barrier between blood and water for favoring gasses exchange with increased efficiency. Microsc. Res. Tech., 2011. © 2011 Wiley‐Liss, Inc.
POVERTY IN RURAL INDIA: VARIATIONS IN FACTORS INFLUENCING DYNAMICS OF CHRONIC POVERTY
Authors: Dhamija Nidhi , Bhide Shashanka 
Published: September 2011

AbstractThe article studies the dynamics of chronic poverty in rural India. The article attempts to analyse the factors influencing the incidence and mobility of poverty and the changes in the influence of these factors over time. This article uses the household panel survey data collected by NCAER. It examines whether there has been change in the influence of factors such as village level infrastructure, household size and composition, and economic growth on poverty dynamics in different periods of time. The impact of a number of factors changes over time implying that the strategies for poverty reduction would have to take into account the changing economic environment. The article further presents an analysis of growth rate of per capita expenditure for the same set households to analyse the extent of consumption growth, which is also an indicator of poverty reduction for rural India. Copyright © 2011 John Wiley & Sons, Ltd.
Metabolic changes in early childhood using LCModel with corrected water scaling method
Authors: Takanashi Jun‐ichi , Somazawa Fuminori , Maruyama Katsuya , Terada Hitoshi , Xu Duan , Barkovich A. James 
Published: September 2011

AbstractPurpose:To examine metabolic changes of the brain in early infancy measured by the LCModel with the water scaling method (LCModel‐WS), and to determine whether the unsuppressed water signal (UWS) on the MR console and the area of the unsuppressed water peak (AUW) in the LCModel can be used to correct metabolite concentrations.Materials and Methods:MR spectroscopy was performed on a 1.5 Tesla MR scanner. To determine whether UWS and AUW increases linearly with PD and exp(‐TE/T2), these values were measured using three phantoms with different PD and T2 values. UWS and AUW were also measured (PRESS, TR = 5000 ms, TE = 30 ms, VOI = 4.5 mL) in 57 pediatric controls (aged 2 weeks to 15 years).Results:Phantom studies revealed UWS and AUW increases linearly with PD and exp(‐TE/T2). UWS and AUW were high in controls younger than 2 years of age, but gradually decreased to become almost constant after 4 years (UWS = 504 × 103, AUW = 2.05 × 107). AUW was linearly proportional to UWS in controls. These indicated that metabolite concentrations should be multiplied by the ratio of UWS/504 × 103 or AUW/2.05 × 107. Age dependent metabolite concentrations corrected by the ratio were obtained.Conclusion:Both UWS and AUW can be used to correct metabolite concentrations; these corrections can significantly improve quantification of metabolites' concentration in early childhood. J. Magn. Reson. Imaging 2012;35:174‐180. © 2011 Wiley Periodicals, Inc.
Fine‐resolution (25 m) topoclimatic grids of near‐surface (5 cm) extreme temperatures and humidities across various habitats in a large (200 × 300 km) and diverse region
Authors: Ashcroft Michael B. , Gollan John R. 
Published: September 2011

AbstractThe development of fine‐resolution climate grids is an important priority in explaining species' distributions at the regional scale and predicting how species may respond to variable and changing climates. Recent studies have demonstrated advantages of producing these grids using large networks of inexpensive climate loggers, as the resulting grids can capture local climatic variations over a range of environments. In this study we extend these methods to develop innovative fine‐resolution (25 m) climate grids for a large region (∼200 × 300 km) of New South Wales, Australia. The key aspects of these grids is that they: (1) are based on near‐surface (5 cm) observations to better reflect where many species live; (2) cover a wide variety of habitats including forests, woodlands and grasslands so that they are broadly applicable; (3) include both temperature and humidity, the latter of which has often been neglected in similar studies; (4) are developed using a variety of climate‐forcing factors rather than relying only on elevation and geographic location; and (5) they focus on the extreme temperatures and humidities regardless of when these occur. Analyses showed that elevation was the dominant factor explaining mild temperatures (low maximums, high minimums), but cold air drainage, distance from coast, canopy cover and topographic exposure had more effect on the extreme maximum and minimum temperatures. Humidities were predominately determined by distance to coast, elevation, canopy cover and topography; however, the relationships were nonlinear and varied in both shape and effect size between dry and moist extremes. Extreme climates occur under specific weather conditions, and our results highlight how averaging climates over seasons or periods of consecutive days will include different weather patterns and obscure important trends. Regional‐scale climate grids can potentially be further improved through a better understanding of how the effects of different climate‐forcing factors vary under different weather conditions. Copyright © 2011 Royal Meteorological Society
Trends in the distributions of aggregated monthly precipitation over the La Plata Basin
Authors: Doyle Moira E. , Saurral Ramiro I. , Barros Vicente R. 
Published: September 2011

AbstractPositive trends in annual rainfall in the La Plata Basin (LPB), south of 20°S observed in the last four decades of the twentieth century were not reversed and became more statistically significant when calculated until 2005. These trends were part of a more general change in the monthly precipitation distribution including extreme precipitation.Precipitation in dry and extremely dry months (below the 35th percentile) has been decreasing in the whole LPB region south of 22°S. On the contrary, precipitation in the above normal (between the 65th and 90th percentile) and the extremely high rainfall (above the 90th percentile) ranges has been increasing accounting for most of the annual precipitation trends. More than a steady trend, there has been an abrupt change in extreme monthly precipitation concentrated between 1977 and 1983.The analysis of intensity and frequency of extreme events was done fitting Generalized Extreme Values (GEV) and Poisson distributions. Each distribution was fitted with and without trends in the location parameter and tested to determine the best fit in each case. The regions where GEV with a positive trend was the best fit coincide with areas affected by extensive floods during the last decades. Spatially aggregated results highlight the signal of change towards higher maximum monthly precipitations for a wide span of return periods.The atmospheric circulation associated with cases where extreme monthly precipitation was observed in most of the stations was studied through the integrated water vapour transport in the lower troposphere and its associated divergence. During warm months, an intense northern low‐level water vapour flow with two convergence nuclei, one over eastern Argentina, southern Brazil and Uruguay, and the other over western Argentina, along with a weakened south Atlantic Convergence Zone was associated with the more extreme precipitation months favouring the occurrence of Mesoscale Convective Systems. Copyright © 2011 Royal Meteorological Society
OSL chronology of sand deposits and climate change of last 18 ka in Gurbantunggut Desert, northwest China
Authors: Li Sheng‐Hua , Fan Anchuan 
Published: September 2011

AbstractThe development of the Gurbantunggut Desert is mainly controlled by the Westerly wind, and at present has little influence from Indian and Southeast Asian monsoons. A combined study using optically stimulated luminescence (OSL) dating, ground‐penetrating radar (GPR) surveys and climatic proxies analysis was carried out in the southern part of the desert. The chronology extends back to 18 ka and is constructed based on 16 OSL ages from boreholes in the linear dune body and the inter‐dune area. The chronology suggests that sand deposition in the last 18 ka experienced two rapid accumulation phases at 11 and 2.5 ka ago which were also evident from the GPR surveys. These periods relate to increased aridity in the region. Five climate phases are identified from the last 18 ka, based on the OSL chronology and climatic proxy analysis with grain size and magnetic susceptibility measurements. The deglacial period (18.3–10.4 ka) is characterized by climate instability and possible glacial melting events. The Holocene Optimum peaked 8.5 ka and terminated 3.6 ka ago, when the regional climate became arid. OSL samples from the dune body cluster around 2.5 ka, which indicates rapid advance/extension of dune bodies at this time. Copyright © 2011 John Wiley & Sons, Ltd.