bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of cattle on browsing and grazing wildlife varies with rainfall and presence of megaherbivores
Authors: Kimuyu Duncan M. , Veblen Kari E. , Riginos Corinna , Chira Robert M. , Githaiga John M. , Young Truman P. 
Published: December 2016

AbstractIn many savanna ecosystems worldwide, livestock share the landscape and its resources with wildlife. The nature of interactions between livestock and wildlife is a subject of considerable interest and speculation, yet little controlled experimental research has been carried out. Since 1995, we have been manipulating the presence and absence of cattle and large mammalian herbivore wildlife in a Kenyan savanna in order to better understand how different herbivore guilds influence habitat use by specific wildlife species. Using dung counts as a relative assay of herbivore use of the different experimental plots, we found that cattle had a range of effects, mostly negative, on common mesoherbivore species, including both grazers and mixed feeders, but did not have significant effects on megaherbivores. The effect of cattle on most of the mesoherbivore species was contingent on both the presence of megaherbivores and rainfall. In the absence of megaherbivores, wild mesoherbivore dung density was 36% lower in plots that they shared with cattle than in plots they used exclusively, whereas in the presence of megaherbivores, wild mesoherbivore dung density was only 9% lower in plots shared with cattle than plots used exclusively. Cattle appeared to have a positive effect on habitat use by zebra (a grazer) and steinbuck (a browser) during wetter periods of the year but a negative effect during drier periods. Plots to which cattle had access had lower grass and forb cover than plots from which they were excluded, while plots to which megaherbivores had access had more grass cover but less forb cover. Grass cover was positively correlated with zebra and oryx dung density while forb cover was positively correlated with eland dung density. Overall these results suggest that interactions between livestock and wildlife are contingent on rainfall and herbivore assemblage and represent a more richly nuanced set of interactions than the longstanding assertion that cattle simply compete with (grazing) wildlife. Specifically, rainfall and megaherbivores seemed to moderate the negative effects of cattle on some mesoherbivore species. Even if cattle tend to reduce wildlife use of the landscape, managing simultaneously for livestock production (at moderate levels) and biodiversity conservation is possible.
Distinct patterns of natural selection in Na+/H+ antiporter genes in Populus euphratica and Populus pruinosa
Authors: Wu Yuxia , Meng Kuibin , Liang Xiaohui 
Published: December 2016

AbstractSalt tolerance genes constitute an important class of loci in plant genomes. Little is known about the extent to which natural selection in saline environments has acted upon these loci, and what types of nucleotide diversity such selection has given rise to. Here, we surveyed genetic diversity in three types of Na+/H+ antiporter gene (SOS, NhaD, and NHX, belonging to the cation/proton antiporter 1 family), which have well‐characterized essential roles in plant salt tolerance. Ten Na+/H+ antiporter genes and 16 neutral loci randomly selected as controls were sequenced from 17 accessions of two closely related members of the genus Populus, Populus euphratica and Populus pruinosa, section Turanga, which are native to northwest China. The results show that salt tolerance genes are common targets of natural selection in P. euphratica and P. pruinosa. Moreover, the patterns of nucleotide variation across the three types of Na+/H+ antiporter gene are distinctly different in these two closely related Populus species, and gene flow from P. pruinosa to P. euphratica is highly restricted. Our results suggest that natural selection played an important role in shaping the current distinct patterns of Na+/H+ antiporter genes, resulting in adaptive evolution in P. euphratica and P. pruinosa.
Managing native fish communities during a long‐term drought
Authors: Baumgartner Lee J. , Wooden Ian J. , Conallin John , Robinson Wayne , Thiem Jason D. 
Published: December 2016

AbstractEcological communities are adapted to extreme hydrological conditions. River regulation can, at times, exacerbate stressors such as drought and flood that threaten population persistence. Conversely, river infrastructure offers a means to deliver water for environmental benefit. Thus knowledge of the life history requirements of native fish, including location‐specific community structure during drought conditions, is required to inform the management of aquatic ecosystems for native fish in regulated systems. During a severe drought, fish community sampling at 30 sites was undertaken in the Edward–Wakool (E–W) river system, an anabranch system of the Murray River, southeast Australia, to provide recommendations into the current management under drought and for future planning. Fish from the E–W system demonstrated diverse responses to drought conditions. Some species recruited under drought conditions, whilst others were restricted in distribution to a few key refuge habitats. The ability for fish species to persist in the long term depends largely on developing appropriate management strategies that both protect critical habitat and sustain biological function. Both situations require a combination of advance planning and reactionary monitoring, which is adaptively used to minimise impacts. Here, we present a number of practical solutions, based on experience from the E–W system, that are applicable to other regulated river systems. It is essential that agencies responsible for drought management ensure appropriate plans are developed ready for implementation in advance of future drought events.
Predicting afforestation impacts on monthly streamflow using the DWBM model
Authors: Zhang Lu , Hickel Klaus , Shao Quanxi 
Published: December 2016

AbstractUnderstanding afforestation impacts on streamflow is important for water resources management. This study presents a predictive method for determining afforestation impacts on streamflow using data from four Australian experimental catchments with considerable forest cover change. Monthly values of rainfall, potential evapotranspiration, and streamflow are available for these catchments, as well as other data including plant available water capacity, minimum and maximum elevations, and index of valley bottom flatness. The proposed method is based on a dynamic water balance model (DWBM) with parameter values estimated from climate and catchment characteristics using projection pursuit regression (PPR). To predict the impacts of afforestation on monthly streamflow, the DWBM model was calibrated for pretreatment conditions and afforestation‐induced changes in the model parameters were determined by adjusting the calibrated model parameter values with PPR predicted model parameter values under pretreatment and posttreatment conditions. Predicted monthly streamflow agreed well with measured streamflow for the period following afforestation. The success of the method indicates that the DWBM model appropriately represents the key catchment processes and characteristics. On the basis of the assessment of model parameter changes, increased storage capacity and evapotranspiration efficiency are the key factors responsible for the reduced monthly streamflow observed. The degree of change in the model parameters due to afforestation is also influenced by other characteristics of the catchments and the local climatic conditions. This study demonstrated the strength of the DWBM model and its ability to predict afforestation impacts on monthly streamflow when combined with the PPR for estimating model parameters.
Optimum seismic design of reinforced concrete frames according to Eurocode 8 and fib Model Code 2010
Authors: Mergos Panagiotis E. 
Published: December 2016

SummaryTraditional seismic design, like the one adopted in Eurocode 8 (EC8), is force‐based and examining a single level of seismic action. In order to provide improved control of structural damage for different levels of seismic action, the new fib Model Code 2010 (MC2010) includes a fully fledged displacement‐based and performance‐based seismic design methodology. However, the level of complexity and computational effort of the MC2010 methodology is significantly increased. Hence, the use of automated optimization techniques for obtaining cost‐effective design solutions becomes appealing if not necessary. This study employs genetic algorithms to derive and compare optimum seismic design solutions of reinforced concrete frames according to EC8 and MC2010. This is important because MC2010 is meant to serve as a basis for future seismic design codes. It is found that MC2010 drives to more cost‐effective solutions than EC8 for regions of low seismicity and better or similar costs for regions of moderate seismicity. For high‐seismicity regions, MC2010 may yield similar or increased structural costs. This depends strongly on the provisions adopted for selecting the set of ground motions. In all cases, MC2010 provides enhanced control of structural damage. Copyright © 2016 John Wiley & Sons, Ltd.
Tolerance of whitefish (Coregonus lavaretus) early life stages to manganese sulfate is affected by the parents
Authors: Arola Hanna E. , Karjalainen Juha , Vehniäinen Eeva-Riikka , Väisänen Ari , Kukkonen Jussi V.K. , Karjalainen Anna K. 
Published: December 2016

Abstract

European whitefish (Coregonus lavaretus) embryos and larvae were exposed to 6 different manganese sulfate (MnSO4) concentrations from fertilization to the 3-d-old larvae. The fertilization success, offspring survival, larval growth, yolk consumption, embryonic and larval Mn tissue concentrations, and transcript levels of detoxification-related genes were measured in the long-term incubation. A full factorial breeding design (4 females × 2 males) allowed examination of the significance of both female and male effects, as well as female–male interactions in conjunction with the MnSO4 exposure in terms of the observed endpoints. The MnSO4 exposure reduced the survival of the whitefish early life stages. The offspring MnSO4 tolerance also was affected by the female parent, and the female-specific mean lethal concentrations (LC50s) varied from 42.0 mg MnSO4/L to 84.6 mg MnSO4/L. The larval yolk consumption seemed slightly inhibited at the exposure concentration of 41.8 mg MnSO4/L. The MnSO4 exposure caused a significant induction of metallothionein-A (mt-a) and metallothionein-B (mt-b) in the 3-d-old larvae, and at the exposure concentration of 41.8 mg MnSO4/L the mean larval mt-a and mt-b expressions were 47.5% and 56.6% higher, respectively, than at the control treatment. These results illustrate that whitefish reproduction can be impaired in waterbodies that receive Mn and SO4 in concentrations substantially above the typical levels in boreal freshwaters, but the offspring tolerance can be significantly affected by the parents and in particular the female parent. Environ Toxicol Chem 2017;36:1343–1353. © 2016 SETAC
Screening of genotoxicity and mutagenicity in extractable organics from oil sands process–affected water
Authors: Zetouni Nikolas C. , Siraki Arno G. , Weinfeld Michael , Pereira Alberto Dos Santos , Martin Jonathan W. 
Published: December 2016

Abstract

Large volumes of oil sands process–affected water (OSPW) are produced by the oil sands surface mining industry during alkaline hot-water extraction of bitumen. It is well documented that the acid extractable organics (AEOs) in OSPW, a highly complex mixture of acidic and polar neutral substances, are acutely toxic; but few studies have examined the genotoxicity or mutagenicity of this mixture. In the present study, the in vitro SOS Chromotest and the Ames test (TA98 and TA100 strains) were used to evaluate genotoxicity and mutagenicity for whole OSPW AEOs in the presence and absence of biotransformation by rat S9 liver enzymes. Two subfractions were also examined in the same assays: neutral extractable fraction (F1-NE), and the subsequent acid extractable fraction (F2-AE). In the SOS assay, whole AEO was cytotoxic when concentrated 2× (i.e., twice as concentrated as the environmental sample) and showed increasing genotoxic response above 6×. Co-exposure with S9 had a protective effect on the cell SOS-inducing factor and survival but did not eliminate genotoxicity above 6× concentrations. Most of the cytotoxicity was attributable to F2-AE, but both F1-NE and F2-AE had similar genotoxic dose–responses above 6×. In the Ames test without S9, whole AEO was mutagenic in both strains above 10× concentrations. Co-incubation with S9 had little effect on the TA100 strain but with TA98 resulted in bioactivation at midlevel doses (1.5–6.3×) and protection at higher doses (10–25×). The 2 subfractions were mutagenic in both strains but with different dose–responses. Further research in vivo or in more relevant cells is warranted to investigate the carcinogenic risks of OSPW. Environ Toxicol Chem 2017;36:1397–1404. © 2016 SETAC
Disruption of rich club organisation in cerebral small vessel disease
Authors: Tuladhar Anil M. , Lawrence Andrew , Norris David. G. , Barrick Thomas R. , Markus Hugh S. , de Leeuw Frank‐Erik 
Published: December 2016

AbstractCerebral small vessel disease (SVD) is an important cause of vascular cognitive impairment. Recent studies have demonstrated that structural connectivity of brain networks in SVD is disrupted. However, little is known about the extent and location of the reduced connectivity in SVD. Here they investigate the rich club organisation—a set of highly connected and interconnected regions—and investigate whether there is preferential rich club disruption in SVD. Diffusion tensor imaging (DTI) and cognitive assessment were performed in a discovery sample of SVD patients (n = 115) and healthy control subjects (n = 50). Results were replicated in an independent dataset (49 SVD with confluent WMH cases and 108 SVD controls) with SVD patients having a similar SVD phenotype to that of the discovery cases. Rich club organisation was examined in structural networks derived from DTI followed by deterministic tractography. Structural networks in SVD patients were less dense with lower network strength and efficiency. Reduced connectivity was found in SVD, which was preferentially located in the connectivity between the rich club nodes rather than in the feeder and peripheral connections, a finding confirmed in both datasets. In discovery dataset, lower rich club connectivity was associated with lower scores on psychomotor speed (β = 0.29, P < 0.001) and executive functions (β = 0.20, P = 0.009). These results suggest that SVD is characterized by abnormal connectivity between rich club hubs in SVD and provide evidence that abnormal rich club organisation might contribute to the development of cognitive impairment in SVD. Hum Brain Mapp 38:1751–1766, 2017. © 2017 Wiley Periodicals, Inc.
Single neuron activity and theta modulation in the posterior parietal cortex in a visuospatial attention task
Authors: Yang Fang‐Chi , Jacobson Tara K. , Burwell Rebecca D. 
Published: December 2016

ABSTRACTThe posterior parietal cortex (PPC) is implicated in directing and maintaining visual attention to locations in space. We hypothesized that the PPC also engages other cognitive processes in the transformation of behaviorally relevant visual inputs into appropriate actions, for example, monitoring of multiple locations, selection of responses to locations in space, and monitoring the outcome of response selections. We recorded single cells and local field potentials in the rat PPC during performance on a novel visuospatial attention (VSA) task that requires visually monitoring locations in space in order to make appropriate stimulus‐guided locomotor responses. In each trial, rats attended to four locations on the floor of a maze. A randomly chosen location was briefly illuminated. Approach to the correct target location was followed by food reward. We observed that PPC activity correlated with multiple phases of the VSA task, including monitoring for stimulus onset, detection of a target, spatial location of the target, and target choice. A substantial proportion of cells with behavioral correlates were also modulated by outcome of the trial. Our analyses of local field potentials revealed strong oscillatory rhythms in the theta frequency band, and more than a third of PPC neurons were phase locked to theta oscillations. As in other brain regions, theta power correlated with running speed. Peak theta power was higher in superficial layers than deep layers providing evidence against volume conduction from the hippocampus. In addition, theta power was sensitive to the outcome of a choice. Theta power was significantly higher following incorrect choices compared with correct choices, possibly providing a prediction error signal. Our study provides evidence that the rat PPC has multiple roles in the translation of visual information into appropriate behavioral actions. © 2016 Wiley Periodicals, Inc.
Investigation of cell viability and morphology in 3D bio‐printed alginate constructs with tunable stiffness
Authors: Shi Pujiang , Laude Augustinus , Yeong Wai Yee 
Published: December 2016

AbstractIn this article, mouse fibroblast cells (L929) were seeded on 2%, 5%, and 10% alginate hydrogels, and they were also bio‐printed with 2%, 5%, and 10% alginate solutions individually to form constructs. The elastic and viscous moduli of alginate solutions, their interior structure and stiffness, interactions of cells and alginate, cell viability, migration and morphology were investigated by rheometer, MTT assay, scanning electron microscope (SEM), and fluorescent microscopy. The three types of bio‐printed scaffolds of distinctive stiffness were prepared, and the seeded cells showed robust viability either on the alginate hydrogel surfaces or in the 3D bio‐printed constructs. Majority of the proliferated cells in the 3D bio‐printed constructs weakly attached to the surrounding alginate matrix. The concentration of alginate solution and hydrogel stiffness influenced cell migration and morphology, moreover the cells formed spheroids in the bio‐printed 10% alginate hydrogel construct. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1009–1018, 2017.
Change in Trabecular Bone Score (TBS) With Antiresorptive Therapy Does Not Predict Fracture in Women: The Manitoba BMD Cohort
Authors: Leslie William D , Majumdar Sumit R , Morin Suzanne N , Hans Didier , Lix Lisa M 
Published: December 2016

ABSTRACT

Bone mineral density (BMD) and trabecular bone score (TBS), along with additional clinical risk factors, can be used to identify individuals at high fracture risk. Whether change in TBS in untreated or treated women independently affects fracture risk is unclear. Using the Manitoba (Canada) DXA Registry containing all BMD results for the population we identified 9044 women age ≥40 years with two consecutive DXA scans and who were not receiving osteoporosis treatment at baseline (baseline mean age 62 ± 10 years). We examined BMD and TBS change, osteoporosis treatment, and incident major osteoporotic fractures (MOFs) for each individual. Over a mean of 7.7 years follow-up, 770 women developed an incident MOF. During the interval between the two DXA scans (mean, 4.1 years), 5083 women initiated osteoporosis treatment (bisphosphonate use 80%) whereas 3961 women did not receive any osteoporosis treatment. Larger gains in both BMD and TBS were seen in women with greater adherence to osteoporosis medication (p for trend &lt;0.001), and the magnitude of the increase was consistently greater for BMD than for TBS. Among treated women there was greater antifracture effect for each SD increase in total hip BMD change (fracture decrease 20%; 95% CI, 13% to 26%; p &lt; 0.001), femoral neck BMD change (19%; 95% CI, 12% to 26%; p &lt; 0.001), and lumbar spine BMD change (9%; 95% CI, 0% to 17%; p = 0.049). In contrast, change in TBS did not predict fractures in women who initiated osteoporosis treatment (p = 0.10). Among untreated women neither change in BMD or TBS predicted fractures. We conclude that, unlike antiresorptive treatment–related changes in BMD, change in lumbar spine TBS is not a useful indicator of fracture risk irrespective of osteoporosis treatment. © 2016 American Society for Bone and Mineral Research.
A Flap Endonuclease (TcFEN1) Is Involved in Trypanosoma cruzi Cell Proliferation, DNA Repair, and Parasite Survival
Authors: Ponce Ivan , Aldunate Carmen , Valenzuela Lucia , Sepúlveda Sofia , Garrido Gilda , Kemmerling Ulrike , Cabrera Gonzalo , Galanti Norbel 
Published: December 2016

ABSTRACTFLAP endonucleases (FEN) are involved both in DNA replication and repair by processing DNA intermediaries presenting a nucleotide flap using its phosphodiesterase activity. In spite of these important functions in DNA metabolism, this enzyme was not yet studied in Trypanosomatids. Trypanosoma cruzi, the ethiological agent of Chagas disease, presents two dividing cellular forms (epimastigote and amastigote) and one non‐proliferative, infective form (trypomastigote). The parasite survives DNA damage produced by reactive species generated in its hosts. The activity of a T. cruzi FLAP endonuclease (TcFEN1) was determined in the three cellular forms of the parasite using a DNA substrate generated by annealing three different oligonucleotides to form a double‐stranded DNA with a 5′ flap in the middle. This activity showed optimal pH and temperature similar to other known FENs. The substrate cut by the flap endonuclease activity could be ligated by the parasite generating a repaired DNA product. A DNA flap endonuclease coding sequence found in the T. cruzi genome (TcFEN1) was cloned, inserted in parasite expression vectors and transfected to epimastigotes. The purified native recombinant protein showed DNA flap endonuclease activity. This endonuclease was found located in the parasite nucleus of transfected epimastigotes and its over‐expression increased both parasite proliferation and survival to H2O2. The presence of a flap endonuclease activity in T. cruzi and its nuclear location are indicative of the participation of this enzyme in DNA processing of flap fragments during DNA replication and repair in this parasite of ancient evolutive origin. J. Cell. Biochem. 118: 1722–1732, 2017. © 2016 Wiley Periodicals, Inc.