bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concentration–discharge relationships reflect chemostatic characteristics of US catchments
Authors: Godsey Sarah E. , Kirchner James W. , Clow David W. 
Published: May 2009

AbstractConcentration–discharge relationships have been widely used as clues to the hydrochemical processes that control runoff chemistry. Here we examine concentration–discharge relationships for solutes produced primarily by mineral weathering in 59 geochemically diverse US catchments. We show that these catchments exhibit nearly chemostatic behaviour; their stream concentrations of weathering products such as Ca, Mg, Na, and Si typically vary by factors of only 3 to 20 while discharge varies by several orders of magnitude. Similar patterns are observed at the inter‐annual time scale. This behaviour implies that solute concentrations in stream water are not determined by simple dilution of a fixed solute flux by a variable flux of water, and that rates of solute production and/or mobilization must be nearly proportional to water fluxes, both on storm and inter‐annual timescales. We compared these catchments' concentration–discharge relationships to the predictions of several simple hydrological and geochemical models. Most of these models can be forced to approximately fit the observed concentration–discharge relationships, but often only by assuming unrealistic or internally inconsistent parameter values. We propose a new model that also fits the data and may be more robust. We suggest possible tests of the new model for future studies. The relative stability of concentration under widely varying discharge may help make aquatic environments habitable. It also implies that fluxes of weathering solutes in streams, and thus fluxes of alkalinity to the oceans, are determined primarily by water fluxes. Thus, hydrology may be a major driver of the ocean‐alkalinity feedback regulating climate change. Copyright © 2009 John Wiley & Sons, Ltd.
Comparison and modification of equations for calculating evapotranspiration (ET) with data from Gansu Province, Northwest China
Authors: Zhai Luxin , Feng Qi , Li Qisen , Xu Cundong 
Published: May 2009

AbstractA total of 11 empirical evapotranspiration equations were developed by Hargreaves (1975), Hargreaves (1985), Makkink, Turc, Priestley–Taylor, Jensen–Haise, Doorenbos and Pruitt, Abtew, McGuinness and Bordne, Rohwer and Blaney–Criddle. These were compared with pan evaporation data measured at 10 stations in Gansu Province, northwest China. The comparison was first made using the default values in each of the 11 equations, and then redone using calibrated coefficient values. The calibration was made for all 11 equations using the climatic index Pa/Pg. The results show that using default coefficient values resulted in large errors for all equations. The largest error was found in the comparison results of the Turc, and McGuinness and Bordne equations. The Turc and Jensen–Haise equations should be used to estimate the daily evapotranspiration (ET) under the conditions of Tmean > 0 and Tmean > −3°C, respectively, when applied to northwest China. Based on the comparison results of before and after recalibration, the Doorenbos and Pruitt method is more suitable to the arid, semiarid and wet regions in northwest China. The accuracy of the results for determining monthly ET greatly improved when calibrated coefficient values were introduced to the 11 equations, except for McGuinness and Bordne, Abtew, and Blaney–Criddle, which need to be recalibrated using two parameters. Thus, it can be concluded that calibration can be used to modify evapotranspiration equations with multi‐station data to improve the accuracy of evapotranspiration estimates in northwest China. Copyright © 2009 John Wiley & Sons, Ltd.
Airborne remote sensing for detection of irrigation canal leakage
Authors: Huang Yanbo , Fipps Guy , Maas Stephan J. , Fletcher Reginald S. 
Published: May 2009

AbstractTraditional field survey methods for detection of water leaks in irrigation canal systems are costly and time‐ consuming. In this study, a rapid, cost‐effective method was developed for identifying irrigation canal locations likely to have leaks and/or seepage. The method involves the use of a multispectral imager equipped with red, near infrared, and thermal sensors which is mounted on an aircraft and flown at low altitude to collect the images. A three‐step process, image acquisition, image processing, and field reconnaissance, was developed for processing the imagery and identification of locations likely to have leaks. The method was evaluated in the Lower Rio Grande Valley of Texas, USA. Images were collected of 24 selected canal segments within 11 irrigation districts in this region. Evaluation of the imagery indicated that 140 sites had possible canal leakage problems (point leak and/or seepage). A field site evaluation form was developed and used to document the type and severity of the leaks at 28 of the sites. Twenty‐six sites were confirmed to have leaks, representing a success rate of 93%. The methods used in this study should have widespread application for detecting leaks and seepage in irrigation canals. Copyright © 2009 John Wiley & Sons, Ltd.
Phytoplankton and Epipelon Responses to Clear and Turbid Phases in a Seepage Lake (Buenos Aires, Argentina)
Authors: Casco María Adela , Mac Donagh María Elicia , Cano María Gabriela , Solari Lía Cristina , Claps María Cristina , Gabellone Néstor Adrián 
Published: May 2009

AbstractAnnual changes in the algal density and concentrations of chlorophyll a, total phosphorus, and organic matter were analyzed in water and sediments at four sites characterized by the presence or absence of submerged and emergent macrophytes, during turbid‐ and clear‐water conditions to determine the contribution of the algal components of the plankton and the epipelon and to identify the most typical species in each community. Three states were recognized: one turbid and two clear, with different submerged macrophyte cover. The peaks of phytoplankton and epipelon occurred in the turbid phase, whereas the highest proportion of true epipelic algae in sediments was reached in the second clear phase. The Oscillatoriaceae dominated during the turbid phase in the water and throughout the entire year within the sediments. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Morphometric and Preliminary Genetic Characteristics of Artemia Populations from Iran
Authors: Agh Naser , Bossier Peter , Abatzopoulos Theodore J. , Beardmore John A. , Stappen Gilbert Van , Mohammadyari Ali , Rahimian Hasan , Sorgeloos Patrick 
Published: May 2009

AbstractSix Artemia populations, one bisexual and five parthenogenetic, from different parts of Iran were compared using morphometric and genetic characteristics. The discriminant analysis based on 19 morphometric variables showed that there are significant differences between the studied populations based on their morphological characteristics, where 85.9% of original grouped cases were correctly classified. The bisexual Artemia urmiana however exhibited a 100% separation from the parthenogenetic populations. However, a 1500 bp mitochondrial rDNA fragment showed similar RFLP patterns for all Iranian populations confirming earlier reports of a close genetic relationship between A. urmiana and parthenogenetic Artemia. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Desiccation and Sediment Type on Early Regeneration of Plant Fragments of Three Species of Aquatic Macrophytes
Authors: Silveira Márcio José , Thomaz Sidinei Magela , Mormul Roger Paulo , Camacho Franciele Pereira 
Published: May 2009

AbstractWe tested the effects of desiccation and type of sediment (clay or sand) on the regeneration of fragments of the apical shoots of three species of Hydrocharitaceae: Egeria najas, E. densa and Hydrilla verticillata. The shoots were left to dry on clay or sand from zero to four days, and were then returned to aquaria containing water. To approximate natural conditions, the aquaria containing clay had higher turbidity and nutrient (P and N) concentrations than did the aquaria with sand. All species dried faster on sand substrate, which led to lower regeneration (in terms of dry weight, length, sprout and root formation) in this treatment. H. verticillata fragments elongated faster than the other species, but E. najas was the most successful species (in terms of increase in dry weight) in the sand treatment. Our results indicate that the exotic H. verticillata has a competitive advantage, at least in its early stages of regeneration, over the other two, native species, especially in more eutrophic and turbid habitats; whereas E. najas fragments have a competitive advantage in less‐turbid, oligotrophic and sand‐dominated sites. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultraviolet Insights: Attempting to Resolve Enigmatic Patterns in Pelagic Freshwaters – The Historical Context and a View to the Future
Authors: Williamson Craig E. , Rose Kevin C. 
Published: May 2009

AbstractWhile great advances have been made in our understanding of pelagic freshwater communities and ecosystems in recent years, several unexplained patterns continue to evade our understanding. While no single factor can explain these enigmatic patterns, recent increases in our understanding of the ecology of ultraviolet radiation (UV) are consistent with UV playing an important role. Here we present a brief overview of why UV has historically received so little attention in pelagic freshwater ecosystems, review some of the important aspects of the ecology of UV that are important to these enigmatic patterns, and discuss how this new understanding of the ecology of UV may provide some insights into these previously unexplained patterns. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Phylogenetic Analysis of Ilyocryptus Sars, 1862 (Cladocera: Ilyocryptidae)
Authors: Kotov Alexey A. , Elías‐Gutiérrez Manuel 
Published: May 2009

AbstractKotov and Štifter (2006) revised the taxonomy of the genus Ilyocryptus Sars, 1862 (Branchiopoda: Anomopoda: Ilyocryptidae) and concluded that 28 species can be recognized as valid for the world fauna. In order to test phylogenetic relationships between the species and to contribute to a better understanding of the genus, a cladistic (using branch‐and‐bound search) analysis was conducted for 25 Ilyocryptus species (two of them with two subspecies). In total, 32 morphological characters were used. An evolutionary‐morphological interpretation of the results was also made. Phylogenetic analysis revealed that Ilyocryptus elegans is an earlier derived member of the genus, while other species are separated into two main branches: agilis ‐ and sordidus ‐lines (without reference to type of moulting). Species with incomplete moulting and species with complete moulting do not form separate clusters, suggesting an independent origin of incomplete moulting within different species groups. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Small Dams on the Benthic Community of Streams in an Atlantic Forest Area of Southeastern Brazil
Authors: Almeida Erick Frota , Oliveira Renata Bley , Mugnai Riccardo , Nessimian Jorge Luiz , Baptista Darcílio Fernandes 
Published: May 2009

AbstractWe examined the effects of longitudinal discontinuity in small rivers, produced by the construction of small dams, on the macroinvertebrate communities in a biological reserve in southeastern Brazil. Two regulated streams were sampled in the rainy and dry seasons at three sites along the river. One site was upstream of the dam/abstraction and two were below the dam. Our results indicate that there was a difference in the communities between the dry and rainy periods even though water physicochemical parameters of the water were not significantly different. The biotic richness at sites 500 m below the dam were similar to those above the impoundment (control), indicating that the fauna recovered when the discharge values found before water abstraction were reestablished. We concluded that the dam did induce changes in the composition of benthic comunities, especially in the dry period. However, overall, the fauna seemed to be able to persist during periods when the flow was absent. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Biomechanical, histological, and ultrastructural analyses of laser micro‐ and nano‐structured titanium alloy implants: A study in rabbit
Authors: Palmquist Anders , Lindberg Fredrik , Emanuelsson Lena , Brånemark Rickard , Engqvist Håkan , Thomsen Peter 
Published: May 2009

AbstractThe aim of this study was to evaluate the biomechanical properties and ultrastructure of the bone response of partly laser‐modified Ti6Al4V implants compared with turned, machined implants after 8 weeks in rabbit. The surface analyses performed with interference microscopy and electron microscopy showed increased surface topography with micro‐ and nano‐sized surface features as well as increased oxide thickness of the modified surface. The biomechanical testing demonstrated a 270% increase in torque value for the surface modified implants compared with the control implants. Histological evaluation of ground sections of specimens subjected to biomechanical testing revealed ongoing bone formation and remodeling. A histological feature exclusively observed at the laser‐modified surface was the presence of fracture in the mineralized bone rather than at the interface between the bone and implant. Transmission electron microscopy (TEM) was performed on Focused Ion Beam (FIB) prepared samples of the intact bone‐implant interface, demonstrating a direct contact between nanocrystalline hydroxyapatite and the oxide of the laser‐modified implant surface. In conclusion, laser‐modified titanium alloy implants have significantly stronger bone anchorage compared with machined implants and show no adverse tissue reactions. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Targeted molecular imaging of VEGF receptors overexpressed in ischemic microvasculature using chitosan‐DC101 conjugates
Authors: Lee Chang‐Moon , Kim Eun‐Mi , Cheong Su‐Jin , Kim Dong‐Wook , Lim Seok Tae , Sohn Myung‐Hee , Jeong Hwan‐Jeong 
Published: May 2009

AbstractExpression of vascular endothelial growth factor receptors (VEGFRs) increases in ischemic muscles, and thus, VEGFR could potentially be used as marker to detect ischemia. Here, we investigated whether 99mTc or Cy5.5‐labeled chitosan‐DC101 conjugates could identify VEGFR‐2 overexpressed in ischemia. To this end, chitosan was conjugated with the DC101 antibody and Cy5.5, FITC, or the HYNIC chelator for 99mTc‐labeling. Targeting of the conjugate was evaluated in vitro and in vivo through cell‐binding studies and gamma/optical imaging, respectively. A hindlimb ischemic mouse model was surgically created by femoral artery occlusion. The chitosan‐DC101 conjugates exhibited VEGFR‐selective cell binding properties as determined by both confocal microscopy and flow cytometry. At postoperative times of 2, 12, and 24 h, 99mTc or Cy5.5‐labeled chitosan‐DC101 conjugates were intravenously injected into the mice, and gamma/optical imaging studies were conducted at 1 or 3 h. Both the gamma and optical imaging results indicated a significantly higher uptake in ischemic muscles when compared with the contralateral nonischemic muscle. Further, semiquantitative analysis of scintigraphic imaging data revealed that the ischemic to contralateral limb ratio was 4.5 ± 0.25 at 24 h postoperation. Western blotting analysis confirmed VEGFR expression in the ischemic muscle. In conclusion, we believe that 99mTc or Cy5.5‐labeled chitosan‐DC101 conjugates have the potential to be useful as VEGFR‐2‐targeted imaging agents for monitoring ischemia. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Bacterial plaque retention on oral hard materials: Effect of surface roughness, surface composition, and physisorbed polycarboxylate
Authors: McConnell Marla D. , Liu Yu , Nowak Andrew P. , Pilch Shira , Masters James G. , Composto Russell J. 
Published: May 2009

AbstractBacterial adhesion to oral hard materials is dependent on various factors, for example, surface roughness and surface composition. In this study, bacteria retention on three oral hard substrates, hydroxyapatite (HAP), enamel, and polished enamel (p‐enamel) were investigated. The surface morphology and roughness of the three substrates were measured by scanning probe microscopy. HAP had the roughest surface, followed by enamel and polished enamel. For each individual substrate type, the roughness was shown to increase with scan size up to 50 μm × 50 μm. For HAP and enamel, roughness decreased considerably after formation of a pellicle, while addition of polymer coating to the pellicle layer reduced roughness much less in comparison. Bacterial surface coverage was measured at 30 min, 3 h, and 24 h on both native and surface‐modified substrates, which were coated with two different polycarboxylate‐based polymers, Gantrez S97 and Carbopol 940. As a result, the polymer coated surfaces had reduced bacteria coverage compared with the native surfaces over all time points and substrates measured. The reduction is the combined effect of electrostatic repulsion and sequestering of Ca2+ ions at the surface, which plays a key role in the initial adhesion of bacteria to enamel surfaces in models of plaque formation. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Titanium particles modulate expression of Toll‐like receptor proteins
Authors: Pajarinen Jukka , Mackiewicz Zygmunt , Pöllänen Raimo , Takagi Michiaki , Epstein Noah J. , Ma Ting , Goodman Stuart B. , Konttinen Yrjö T. 
Published: May 2009

AbstractThe role of Toll‐like receptors (TLRs) responding to microbial remnants, indolent biofilms or cellular byproducts in aseptic loosening of joint replacements is unknown. Thus, the effect of titanium (Ti) particles on TLR protein levels was evaluated. To create a model of particle‐induced inflammation, an intramedullary stainless steel rod with and without Ti particles was bilaterally placed in the femora of 14 mice. The animals were sacrificed at 2 or 10 weeks postoperatively and paraffin‐embedded femur sections were evaluated for TLR1, 2, 4, 5, 8, and 9 proteins using immunohistochemistry. Decrease in the number of TLR immunoreactive cells was observed between weeks 2 and 10 in both settings. Furthermore, in the presence of Ti particles, the numbers of TLR immunoreactive cells were lower than in the presence of rod only at both time points, suggesting downregulation of TLR expression by Ti‐particles per se. Accordingly, in a short‐term 24 h stimulation, downregulation of TLR4 mRNA (p < 0.02) was observed in vitro in RAW 264.7 cells challenged with Ti particles. Results suggest that after an initial inflammatory stage, TLRs are downregulated in response to Ti particles, possibly to inhibit excessive inflammation, although TLR downregulation might at the same time render tissues more susceptible to pathogens. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Parentage and relatedness in captive and natural populations of the Roseate Spoonbill (Aves: Ciconiiformes) based on microsatellite data
Authors: Miño Carolina Isabel , Sawyer Gregory Martin , Benjamin Robert Curliss , Del Lama Silvia Nassif 
Published: May 2009

AbstractThis study constitutes a first approach to evaluate the use of genetic information and relatedness estimators in the investigation of questions related to mating system and parentage in ex situ and in situ populations of the Roseate Spoonbill. We assessed the parentage assignments in 17 supposed families from US captive populations and investigated the genetic relationships among 67 nestlings sampled within 28 nests in Brazilian natural breeding colonies. Estimations of genetic relatedness values, hypothesis testing methods, simulations and maximum likelihood approaches were performed on data from four microsatellite loci. Parentage was confirmed in 61.5% of the registered parent–offspring relationships at zoo parks. Inconsistencies in assignments were investigated and the likely parents were identified for most of the hatchlings. Matings among relatives, not previously noticed based on behavioral observations, were identified by the use of genetic analyses. In natural populations, 33% of the sampled dyads were confidently classified as full‐sibs. Above 25% of the analyzed dyads were unrelated, indicating that more than one parent‐pair may have been responsible for the progeny. Our results demonstrate that genetic information can augment the precision in parentage assignment in captive Roseate Spoonbill populations, and this approach can contribute to their management and conservation. Results obtained using three different methodologies are concordant and point to the existence of a mating system other than monogamy for this species in the wild. The approaches implemented in this study can be applied to other waterbird species in which capture of adults is difficult. J. Exp. Zool. 311A:453–464, 2009. © 2009 Wiley‐Liss, Inc.
Seasonal pelage changes are synchronized by simulated natural photoperiods in Siberian hamsters (Phodopus sungorus)
Authors: Butler Matthew P. , Zucker Irving 
Published: May 2009

AbstractThe extent to which changing day lengths (DLs) synchronize the seasonal molt was assessed in nine cohorts of male and female Siberian hamsters (Phodopus sungorus) born into a simulated natural photoperiod (SNP) beginning 4 weeks before and ending 12 weeks after the summer solstice. Hamsters in early cohorts displayed rapid somatic and gonadal growth and early puberty, whereas those in later cohorts delayed puberty until the next spring. Despite the varying birth dates and puberty strategies, the seasonal pattern of change in pelage is much better predicted by calendar date than by age in both sexes. Males born over the course of 16 weeks first made the transition to the winter pelage during a 5‐week interval beginning on October 25; the autumn molt, however, was not significantly synchronized by either age or calendar date. The autumn molt of females on the other hand began 2 weeks later, and was significantly synchronized to calendar date with no detectable age effects. In both sexes, the autumn molt lagged gonadal and somatic seasonal changes by many weeks. Date of birth did not affect the timing of the spring molt, which was significantly synchronized by calendar date in both sexes. Incrementally changing photoperiods exert a strong organizing effect on the seasonal molt by providing hamsters with timing cues that are absent in laboratory analyses that employ static DLs and abrupt transitions from summer to winter DLs, thereby extending and validating conclusions derived from previous analyses. J. Exp. Zool. 311A:475–382, 2009. © 2009 Wiley‐Liss, Inc.