bluuebunny/crossref_metadata_2025_split huggingface dataset:
Underestimated ranges and overlooked refuges from amphibian chytridiomycosis
Authors: Puschendorf Robert , Hodgson Lauren , Alford Ross A. , Skerratt Lee F. , VanDerWal Jeremy 
Published: May 2013

AbstractAimAccurately documenting and predicting declines and shifts in species’ distributions is fundamental for implementing effective conservation strategies and directing future research; species distribution models (SDM) have become a powerful tool for such work. Nevertheless, much of the data used to create these models are opportunistic and often violate some of their basic assumptions. We use amphibian declines and extinctions linked to the fungus Batrachochytrium dendrobatidis (Bd) to examine how sampling biases in data collection can affect what we know of this disease and its effect on amphibians in the wild.LocationQueensland, Australia.MethodsWe developed a distribution model for Bd incorporating known locality records for Bd and a subset of climatic variables that should correctly characterize its distribution. We tested this (original) model with additional surveys, recorded new Bd observations in novel environments and reran the distribution model. We then investigated the difference between the original and new models, and used frog abundance and infection status data from two of these new localities to look at the susceptibility of the torrent frog Litoria nannotis to chytridiomycosis.ResultsWhile largely correct, the original SDM underestimated the distribution of Bd; sampling in ‘unsuitable’ drier environments discovered abundant populations of susceptible frogs with pathogen prevalences of up to 100%. The validation surveys further uncovered a new population of the frog Litoria lorica coexisting with the pathogen; this species was previously believed to be an extinct rain forest endemic.Main conclusionOur results indicate that SDMs constructed using opportunistically collected data can be biased if species are not at equilibrium with their environment or because environmental gradients have not been adequately sampled. For disease ecology, the better estimations of pathogen distribution may lead to the discovery of new populations persisting at the edge of their range, which has important implications for the conservation of species threatened by chytridiomycosis.
Global change effects on the long‐term feeding ecology and contaminant exposures of East Greenland polar bears
Authors: McKinney Melissa A. , Iverson Sara J. , Fisk Aaron T. , Sonne Christian , Rigét Frank F. , Letcher Robert J. , Arts Michael T. , Born Erik W. , Rosing‐Asvid Aqqalu , Dietz Rune 
Published: May 2013

AbstractRapid climate changes are occurring in the Arctic, with substantial repercussions for arctic ecosystems. It is challenging to assess ecosystem changes in remote polar environments, but one successful approach has entailed monitoring the diets of upper trophic level consumers. Quantitative fatty acid signature analysis (QFASA) and fatty acid carbon isotope (δ13C‐FA) patterns were used to assess diets of East Greenland (EG) polar bears (Ursus maritimus) (n = 310) over the past three decades. QFASA‐generated diet estimates indicated that, on average, EG bears mainly consumed arctic ringed seals (47.5 ± 2.1%), migratory subarctic harp (30.6 ± 1.5%) and hooded (16.7 ± 1.3%) seals and rarely, if ever, consumed bearded seals, narwhals or walruses. Ringed seal consumption declined by 14%/decade over 28 years (90.1 ± 2.5% in 1984 to 33.9 ± 11.1% in 2011). Hooded seal consumption increased by 9.5%/decade (0.0 ± 0.0% in 1984 to 25.9 ± 9.1% in 2011). This increase may include harp seal, since hooded and harp seal FA signatures were not as well differentiated relative to other prey species. Declining δ13C‐FA ratios supported shifts from more nearshore/benthic/ice‐associated prey to more offshore/pelagic/open‐water‐associated prey, consistent with diet estimates. Increased hooded seal and decreased ringed seal consumption occurred during years when the North Atlantic Oscillation (NAO) was lower. Thus, periods with warmer temperatures and less sea ice were associated with more subarctic and less arctic seal species consumption. These changes in the relative abundance, accessibility, or distribution of arctic and subarctic marine mammals may have health consequences for EG polar bears. For example, the diet change resulted in consistently slower temporal declines in adipose levels of legacy persistent organic pollutants, as the subarctic seals have higher contaminant burdens than arctic seals. Overall, considerable changes are occurring in the EG marine ecosystem, with consequences for contaminant dynamics.
Sensitivity of salmonid freshwater life history in western US streams to future climate conditions
Authors: Beer W. Nicholas , Anderson James J. 
Published: May 2013

AbstractWe projected effects of mid‐21st century climate on the early life growth of Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) in western United States streams. Air temperature and snowpack trends projected from observed 20th century trends were used to predict future seasonal stream temperatures. Fish growth from winter to summer was projected with temperature‐dependent models of egg development and juvenile growth. Based on temperature data from 115 sites, by mid‐21st century, the effects of climate change are projected to be mixed. Fish in warm‐region streams that are currently cooled by snow melt will grow less, and fish in suboptimally cool streams will grow more. Relative to 20th century conditions, by mid‐21st century juvenile salmonids' weights are expected to be lower in the Columbia Basin and California Central Valley, but unchanged or greater in coastal and mountain streams. Because fish weight affects fish survival, the predicted changes in weight could impact population fitness depending on other factors such as density effects, food quality and quantity changes, habitat alterations, etc. The level of year‐to‐year variability in stream temperatures is high and our analysis suggests that identifying effects of climate change over the natural variability will be difficult except in a few streams.
Anomalous, extreme weather disrupts obligate seed dispersal mutualism: snow in a subtropical forest ecosystem
Authors: Zhou Youbing , Newman Chris , Chen Jin , Xie Zongqiang , Macdonald David W. 
Published: May 2013

AbstractOngoing global climate change is predicted to increase the frequency and magnitude of extreme weather events, impacting population dynamics and community structure. There is, however, a critical lack of case studies considering how climatic perturbations affect biotic interactions. Here, we document how an obligate seed dispersal mutualism was disrupted by a temporally anomalous and meteorologically extreme interlude of unseasonably frigid weather, with accompanying snowstorms, in subtropical China, during January–February 2008. Based on the analysis of 5892 fecal samples (representing six mammalian seed dispersers), this event caused a substantial disruption to the relative seed dispersal function for the raisin tree Hovenia dulcis from prestorm 6.29 (2006) and 11.47 (2007), down to 0.35 during the storm (2008). Crucially, this was due to impacts on mammalian seed dispersers and not due to a paucity of fruit, where 4.63 fruit per branch were available in January 2008, vs. 3.73 in 2006 and 3.58 in 2007. An induced dietary shift occurred among omnivorous carnivores during this event, from the consumption fruit to small mammals and birds, reducing their role in seed dispersal substantially. Induced range shift extinguished the functionality of herbivorous mammals completely, however, seed dispersal function was compensated in part by three omnivorous carnivores during poststorm years, and thus while the mutualism remained intact it was enacted by a narrower assemblage of species, rendering the system more vulnerable to extrinsic perturbations. The storm's extended effects also had anthropogenic corollaries – migrating ungulates becoming exposed to heightened levels of illegal hunting – causing long‐term modification to the seed dispersal community and mutualism dynamics. Furthermore, degraded forests proved especially vulnerable to the storm's effects. Considering increasing climate variability and anthropogenic disturbance, the impacts of such massive, aberrant events warrant conservation concern, while affording unique insights into the stability of mutualisms and the processes that structure biodiversity and mediate ecosystem dynamics.
Maintenance of temporal synchrony between syrphid flies and floral resources despite differential phenological responses to climate
Authors: Iler Amy M. , Inouye David W. , Høye Toke T. , Miller‐Rushing Abraham J. , Burkle Laura A. , Johnston Eleanor B. 
Published: May 2013

AbstractVariation in species’ responses to abiotic phenological cues under climate change may cause changes in temporal overlap among interacting taxa, with potential demographic consequences. Here, we examine associations between the abiotic environment and plant–pollinator phenological synchrony using a long‐term syrphid fly–flowering phenology dataset (1992–2011). Degree‐days above freezing, precipitation, and timing of snow melt were investigated as predictors of phenology. Syrphids generally emerge after flowering onset and end their activity before the end of flowering. Neither flowering nor syrphid phenology has changed significantly over our 20‐year record, consistent with a lack of directional change in climate variables over the same time frame. Instead we document interannual variability in the abiotic environment and phenology. Timing of snow melt was the best predictor of flowering onset and syrphid emergence. Snow melt and degree‐days were the best predictors of the end of flowering, whereas degree‐days and precipitation best predicted the end of the syrphid period. Flowering advanced at a faster rate than syrphids in response to both advancing snow melt and increasing temperature. Different rates of phenological advancements resulted in more days of temporal overlap between the flower–syrphid community in years of early snow melt because of extended activity periods. Phenological synchrony at the community level is therefore likely to be maintained for some time, even under advancing snow melt conditions that are evident over longer term records at our site. These results show that interacting taxa may respond to different phenological cues and to the same cues at different rates but still maintain phenological synchrony over a range of abiotic conditions. However, our results also indicate that some individual plant species may overlap with the syrphid community for fewer days under continued climate change. This highlights the role of interannual variation in these flower–syrphid interactions and shows that species‐level responses can differ from community‐level responses in nonintuitive ways.
Hepatitis C virus relapse was suppressed by long‐term self‐injection of low‐dose interferon in patients with chronic hepatitis C after pegylated interferon plus ribavirin treatment
Authors: Takashima Tomoyuki , Enomoto Hirayuki , Ninomiya Toshiaki , Kim Soo Ryang , Okushin Hiroaki , Sugano Masahiko , Imoto Susumu , Yano Yoshihiko , Ooka Teruji , Seo Yasushi , Kasugai Hiroshi , Muramatsu Akira , Jomura Hisato , Shimomura Soji , Shindo Michiko , Nakamura Hideji , Aizawa Nobuhiro , Iwata Yoshinori , Saito Masaki , Imanishi Hiroyasu , Iijma Hiroko , Nishiguchi Shuhei 
Published: May 2013

AimThe recommended treatment for chronic hepatitis C is a combination of pegylated interferon (PEG IFN) plus ribavirin (RBV). However, the sustained virological response (SVR) rate of PEG IFN‐RBV therapy was approximately 50% in patients with genotype 1b and a high viral load. Thus, we compared the efficiencies and side‐effects of PEG IFN‐RBV and self‐injected low‐dose natural (n) IFN‐α in patients with hepatitis C virus (HCV).MethodsA prospective, multicenter, open‐label study was conducted in 12 Japanese institutions. A total of 129 patients with chronic hepatitis C and no detectable HCV after 24–72 weeks of PEG IFN‐RBV treatment were assigned to the control (n = 82) or treated (n = 47) group. Treated patients received 3 million units of nIFN‐α 2–3 times/week over 96 weeks. The groups were compared regarding treatment efficiency and side‐effects.ResultsSignificant treatment success regarding virus negativation rates was found, with 89% and 73% for the treated and control groups, respectively (P = 0.039). In contrast, there was no difference in relapse rate between the groups 24 weeks after the 96‐week nIFN‐α treatment (P = 0.349). However, when early viral responders and late viral responders (LVR) were separated, LVR patients responded significantly to the treatment with 90% sustained virological response, compared to 53% for the control group (P = 0.044). The side‐effects of nIFN‐α were less than that of PEG IFN‐RBV treatment.ConclusionSelf‐injected nIFN‐α has larger benefits than prolonged PEG IFN‐RBV for chronic hepatitis C patients with high viral loads of genotype 1b who fail to achieve early viral response during initial combination treatment.
Robotic partial nephrectomy: Current technique and outcomes
Authors: Wang Liang , Lee Benjamin R 
Published: May 2013

AbstractOver the past decade, management of the T1 renal mass has focused on nephron‐sparing surgery. Robotic partial nephrectomy has played an increasing role in the technique of preserving renal function by decreasing warm ischemia time, as well as optimizing outcomes of hemorrhage and fistula. Robot‐assisted partial nephrectomy is designed to provide a minimally‐invasive nephron‐sparing surgical option utilizing reconstructive capability, decreasing intracorporeal suturing time, technical feasibility and safety. Ultimately, its benefits are resulting in its dissemination across institutions. Articulated instrumentation and three‐dimensional vision facilitate resection, collecting system reconstruction and renorrhaphy, leading to decreased warm ischemia time while preserving oncological outcomes. The aim of the present review was to present our surgical sequence and technique, as well as review the current status of robot‐assisted partial nephrectomy.
A statistical strategy to identify recombinant viral ribonucleoprotein of avian, human, and swine influenza A viruses with elevated polymerase activity
Authors: Chin Alex W. H. , Greenbaum Benjamin D. , Li Olive T. W. , Webby Richard J. , Poon Leo L. M. 
Published: May 2013

ObjectivesReassortment of influenza A viruses can give rise to viral ribonucleoproteins (vRNPs) with elevated polymerase activity and the previous three pandemic influenza viruses contained reassorted vRNPs of different origins. These suggest that reassorted vRNP may be one of the factors leading to a pandemic virus. In this study, we reconstituted chimeric vRNPs with three different viral strains isolated from avian, human and swine hosts. We applied a statistical strategy to identify the effect that the origin of a single vRNP protein subunit or the interactions between these subunits on polymerase activity.DesignEighty one chimeric vRNPs were reconstituted in 293T cells at different temperatures. Polymerase activity was determined by luciferase reporter assay and the results were analysed by multiway anova and other statistical methods.ResultsIt was found that PB2, PB1, NP, PB2‐PB1 interaction, PB2‐PA interaction and PB1‐NP interaction had significant effect on polymerase activity at 37°C and several single subunits and interactions were identified to lead to elevation of polymerase activity. Furthermore, we studied 27 out of these 81 different chimieric vRNPs in different combinations via fractional factorial design approach. Our results suggested that the approach can identify the major single subunit or interaction factors that affect the polymerase activity without the need to experimentally reproduce all possible vRNP combinations.ConclusionsStatistical approach and fractional factorial design are useful to identify the major single subunit or interaction factors that can modulate viral polymerase activity.
Comparison of total energy expenditure between school and summer months
Authors: Zinkel S. R. J. , Moe M. , Stern E. A. , Hubbard V. S. , Yanovski S. Z. , Yanovski J. A. , Schoeller D. A. 
Published: May 2013

SummaryWhat is already known about this subject
Childhood obesity has increased 3 to 4 fold.
Some children gain excess weight in summer.
What this study adds
Total energy expenditure increases almost linearly with fat‐free mass.
A lower total energy expenditure was not detected in summer.
ObjectiveRecent data report that the youth experience greater weight gain during summer than during school months. We tested the hypothesis that a difference in total energy expenditure (TEE) between school and summer months exists and may contribute to summer weight gain.Subjects and methodsA secondary analysis was performed on cross‐sectional TEE data from school‐age, sedentary African–American and Caucasian youth based in or near the District of Columbia who were at‐risk for adult obesity because they had body mass index (BMI) ≥ 85th percentile or had overweight parents. TEE was estimated from 18‐O and deuterium measurements during 1‐week intervals using urine samples collected after ingestion of doubly labelled water. Differences in summer‐ and school‐time TEE were assessed using analysis of covariance. The data were adjusted for fat‐free mass (FFM) as determined by deuterium dilution to adjust for the effect of body size on TEE.ResultsData were collected from 162 youth (average age 10 ± 2 years, BMI 28 ± 8 kg m−2 and BMI z‐score 1.96 + 0.96). Of these, 96 youth had TEE measured during the school year (September–June); 66 different youths had TEE measured during summer months (June–August). After adjustment for FFM, average summertime TEE was 2450 ± 270 kcal d−1 and average school‐time TEE was 2510 ± 350 kcal d−1 (P = 0.26).ConclusionNo difference in TEE was detected between the school year and the summer months. These data suggest that seasonal differences in youth weight gain are not necessarily due to differences in energy expenditures.
Plastic Forming of High‐TcYBa2Cu3O7−x Bulk Superconductors
Authors: Takahashi Makoto , Sawada Kengo , Ishikawa Hiroyuki , Omi Tatsunosuke , Ohkido Sadao , Tahashi Masahiro , Wakita Koichi 
Published: May 2013

The large bulk high‐Tc YBa2Cu3O7−x (YBCO) superconductor samples were prepared by plastic‐forming method. We examined the effects of the solvent and the crystallinity of YBCO powder on the composition, crystallinity, and superconducting properties of YBCO sheet samples (sample size: 50 mm × 50 mm× 3 mm). By changing the solvent from water to turpentine oil, the leaching of Ba2+ ions from YBa2Cu3(OH)y multimetallic hydroxide particles used as an inorganic binder and the YBCO powder were reduced. This results in the composition of the grain boundaries of fired YBCO sheet samples to be the same as the composition of YBa2Cu3(OH)y multimetallic hydroxide particles. Changing nondoped YBCO powder prepared by sintering to 5 wt% Pt‐doped YBCO powder prepared by melt texturing, Jc value of YBCO sheet samples changed from about 700 to 6,106 A/cm2 at 77 K.
Thermoelectric Properties of Reduced Polycrystalline Sr0.5Ba0.5Nb2O6 Fabricated Via Solution Combustion Synthesis
Authors: Dandeneau Christopher S. , Bodick Tyler W. , Bordia Rajendra K. , Ohuchi Fumio S. 
Published: May 2013

The thermoelectric properties of bulk polycrystalline Sr0.5Ba0.5Nb2O6 (SBN50) fabricated via solution combustion synthesis (SCS) and reduced at temperatures of 900°C–1150°C were explored. The Seebeck coefficient (S) of all samples increased over the entire range of testing temperatures; a peak S value of −281 μV/K was obtained at 930 K for the sample reduced at 900°C. A metal‐insulator transition was observed in the electrical conductivity (σ) of samples reduced at 1000°C–1150°C, whereas only semiconducting electrical behavior was observed for the sample reduced at 900°C. An optimal balance between S and σ was achieved for the pellet reduced at 1000°C, which exhibited a maximum power factor of 1.78 μW/cm·K2 at 930 K. Over a temperature range of 300–930 K, the thermal conductivity (κ) of as‐processed and reduced (1000°C) SBN50 was found to be 1.03–1.4 and 1.46–1.84 W/m·K, respectively. A maximum figure of merit (ZT) of 0.09 was obtained at 930 K for the 1000°C‐reduced sample. X‐ray photoelectron spectroscopy revealed that the Nb2+ peak intensity increased at higher reduction temperatures, which could possibly lead to a distortion of NbO6 octahedra and a decrease in the Seebeck coefficient.
Combustion Synthesis of Ca2Si5N8: Eu2+ Phosphors and their Luminescent properties
Authors: Chung Shyan‐Lung , Chou Wei‐Chi 
Published: May 2013

A combustion synthesis method has been developed for synthesis of Eu2+‐doped Ca2Si5N8 phosphor and its photoluminescence properties were investigated. Ca, Si, and Eu2O3 powders were used as the Ca, Si, and Eu sources. NaN3 and NH4Cl were found necessary to be added for the formation of the product phase and addition of Si3N4 was found to enhance the product yield. These powders were mixed and pressed into a compact, which was then wrapped up with an igniting agent (Mg + Fe3O4). The reactant compact was ignited by electrical heating under a N2 pressure of 0.7 MPa. Effects of these experimental parameters on the product yield were investigated and a reaction mechanism was proposed. The synthesized Ca2Si5N8: Eu2+ phosphor absorbs light in the region of 300–520 nm and shows a broad band emission in the region of 500–670 nm due to the 4f65d1 → 4f7 transition of Eu2+. Eu2O3 was found partially unreacted and a certain amount of oxygen is believed to be incorporated into the lattice of the product phase. The peak emission intensity (~93% of a commercially available phosphor, YAG:Ce3+v) and the peak emission wavelength (571–581 nm) were found to be lower and shorter, respectively, than that reported in the literature. These are considered to be mainly due to oxygen incorporation, which not only reduces nephelauxetic effect and crystal field splitting but also causes a lowering of internal quantum efficiency.
Formation of functional gap junctions in amniotic fluid‐derived stem cells induced by transmembrane co‐culture with neonatal rat cardiomyocytes
Authors: Connell Jennifer Petsche , Augustini Emily , Moise Kenneth J. , Johnson Anthony , Jacot Jeffrey G. 
Published: May 2013

AbstractAmniotic fluid‐derived stem cells (AFSC) have been reported to differentiate into cardiomyocyte‐like cells and form gap junctions when directly mixed and cultured with neonatal rat ventricular myocytes (NRVM). This study investigated whether or not culture of AFSC on the opposite side of a Transwell membrane from NRVM, allowing for contact and communication without confounding factors such as cell fusion, could direct cardiac differentiation and enhance gap junction formation. Results were compared to shared media (Transwell), conditioned media and monoculture media controls. After a 2‐week culture period, AFSC did not express cardiac myosin heavy chain or troponin T in any co‐culture group. Protein expression of cardiac calsequestrin 2 was up‐regulated in direct transmembrane co‐cultures and media control cultures compared to the other experimental groups, but all groups were up‐regulated compared with undifferentiated AFSC cultures. Gap junction communication, assessed with a scrape‐loading dye transfer assay, was significantly increased in direct transmembrane co‐cultures compared to all other conditions. Gap junction communication corresponded with increased connexin 43 gene expression and decreased phosphorylation of connexin 43. Our results suggest that direct transmembrane co‐culture does not induce cardiomyocyte differentiation of AFSC, though calsequestrin expression is increased. However, direct transmembrane co‐culture does enhance connexin‐43‐mediated gap junction communication between AFSC.