bluuebunny/crossref_metadata_2025_split huggingface dataset:
Peak season carbon exchange shifts from a sink to a source following 50+ years of herbivore exclusion in an Arctic tundra ecosystem
Authors: Lara Mark J. , Johnson David R. , Andresen Christian , Hollister Robert D. , Tweedie Craig E. 
Published: August 2016

Summary

To date, the majority of our knowledge regarding the impacts of herbivory on arctic ecosystem function has been restricted to short‐term (<5 years) exclusion or manipulation experiments. Our understanding of long‐term responses of sustained herbivory and/or herbivore exclusion on arctic tundra ecosystem function is severely limited.

Recent evidence suggests lemming population outbreaks, which have historically been common in tundra regions, have become less frequent and in some cases disappeared. Here, we evaluate how 50+ years of lemming absence have impacted ecosystem carbon and energy exchange in an Arctic tundra region near Barrow, Alaska, using some of the oldest herbivore exclosures in the Arctic.

We show that sustained lemming absence dramatically altered peak growing season ecosystem function (i.e. thaw depth, water‐table, NDVI, albedo and land atmosphere CO2 and CH4 exchange) in all land cover types (i.e. wet, moist and dry) investigated but was most profound in wet tundra, where the long‐term absence of lemmings altered the largest carbon sink during peak growing season into a source to the atmosphere. Landscape‐level analysis suggests the long‐term absence of lemmings may increase peak growing season albedo by +6% and decrease net ecosystem exchange, CH4 flux and the combined radiative forcing potential by −96, −79 and −104%, respectively.

Identified long‐term functional responses to herbivory differed from many short‐term exclusion studies, as we found higher rates of carbon uptake where herbivores are present, associated with a shift in plant community composition (i.e. graminoid to moss), while short‐term studies typically report a reduction in carbon uptake where herbivores are present, associated with defoliation events that decrease above‐ground biomass/photosynthesis.

Synthesis. This work highlights the long‐term impact of herbivory on ecosystem function, which suggests (i) the measured response of arctic tundra to herbivory may be dependent on the duration of experimental observation, and (ii) if negative trends in lemming populations persist in arctic tundra regions, the historically strong carbon sink capacity may be severely reduced.
Taxonomic resolution is a determinant of biodiversity effects in arbuscular mycorrhizal fungal communities
Authors: Yang Haishui , Zhang Qian , Koide Roger T. , Hoeksema Jason D. , Tang Jianjun , Bian Xinmin , Hu Shuijin , Chen Xin 
Published: August 2016

Summary

Arbuscular mycorrhizal fungi (AMF) are key regulators of ecosystem processes, yet how their biodiversity works in ecosystems remains poorly understood.

We documented the extent to which taxonomic resolution influenced the effect of biodiversity of AMF taxa on plant performance (growth, nutrient uptake and stress tolerance) in a meta‐analysis of 902 articles.

We found that the effect of biodiversity of AMF taxa depended on taxonomic resolution. Plant performance was positively promoted by AMF family richness, while no effect was found for fungal species richness. In addition, negative effect was found between AMF phylogenetic diversity and plant growth. This pattern can be explained by functional conservatism within AMF families and functional differentiation among AMF families.

Synthesis. Conservation of AMF communities to maintain a full complement of ecosystem functions requires the presence of diverse families and not simply diverse species within a family. This finding may be of key importance for the function of ecosystems under various environmental perturbations to which AMF families may respond differently.
Associations ofP2Y12Rgene polymorphisms with susceptibility to coronary heart disease and clinical efficacy of antiplatelet treatment with clopidogrel
Authors: Yang Hong‐Hui , Chen Yan , Gao Chuan‐Yu 
Published: August 2016

SummaryObjectiveTo investigate the correlations of threeP2Y12 receptor (P2Y12R)gene polymorphisms (rs7428575 T>G, rs2046934 C>T, and rs3732759 A>G) with susceptibility to coronary artery disease (CHD) and clinical efficacy of clopidogrel treatment forCHD.MethodsFrom May 2014 to May 2015, 178CHDpatients (the case group) and 182 healthy controls (the control group) were selected from our hospital. The platelet‐rich plasma (PRP) turbidimetry was used to measure the rate of adenosine diphosphate (ADP)‐induced platelet aggregation before and after clopidogrel treatment. Clopidogrel‐sensitive group was defined as a 10% or greater decrease in the rate of platelet aggregation after 10 days of clopidogrel treatment, while clopidogrel‐resistant group was defined as a <10% decrease. Genotyping was performed by denaturing high‐performance liquid chromatography (DHPLC). A haplotype analysis ofP2Y12Rgene polymorphisms was performed usingSHEsis software.ResultsThere were significant differences in genotype and allele frequencies of rs2046934 C>T and rs3732759 A>G between the case and control groups (allP<.05). HaplotypesGTAandTTAwere negatively associated withCHDrisk (bothP<.05), but haplotypeTCAwas positively associated withCHDrisk (P=.005).CHDpatients in the clopidogrel‐sensitive group had higher frequencies ofTTgenotype of rs2046934 C>T and lower frequencies ofGGgenotype of rs3732759 A>G than those in the clopidogrel‐resistant group (bothP<.05).ConclusionsP2Y12Rgene rs2046934 C>T and rs3732759 A>G polymorphisms might be associated with the risk ofCHDand the efficacy of clopidogrel treatment forCHD.
Warfarin persistence among atrial fibrillation patients – why is treatment ended?
Authors: Björck Fredrik , Ek Agnes , Johansson Lars , Själander Anders 
Published: August 2016

SummaryBackground and AimWarfarin treatment discontinuation is significant among patients with atrial fibrillation (AF). Studies mainly focused on whether the proportion of warfarin persistence and discontinuation are clinically appropriate are absent. This study evaluates warfarin persistence with focus on predictors for, and reasons to, warfarin discontinuation in AF patients.MethodsFrom the national quality register AuriculA, all AF patients in Sundsvall, Sweden, on warfarin treatment on January 1, 2010 were included. These 478 patients were followed until discontinuation or study‐stop, December 31, 2013. By going through each patient's medical record, risk factors for thromboembolism, bleeding, and causes of discontinuation were obtained.ResultsProportion of warfarin persistence was 0.91 (95% confidence interval [CI] 0.89–0.93) after 1 year and 0.73 (95% CI: 0.69–0.77) after 4 years. Previous intracranial bleeding, excessive alcohol use, anemia, and pulmonary or peripheral emboli were each associated with over two times higher risk of discontinuation (hazard ratio [HR] 5.66, CI 2.23–14.36; HR 2.54, CI 1.48–4.37; HR 2.40, CI 1.38–4.17; and HR 2.13, CI 1.02–4.46). Among patients discontinuing, 50.5% were due to questionable causes, such as sinus rhythm (33.9%), patients demand (10.1%), and falls (8.2%). The majority (43.1%) of treatment discontinuers were changed to aspirin, while 40.4% of them were left without medical stroke prophylaxis.ConclusionsAlthough persistence to warfarin among AF patients proves higher than previously reported, there is room for improvement since half of the discontinuers have questionable reasons for treatment stop and the majority of them receive no other efficient stroke prophylaxis.
Similarity in spatial utilization distributions measured by the earth mover's distance
Authors: Kranstauber Bart , Smolla Marco , Safi Kamran 
Published: August 2016

Summary

Estimating the similarity in space use (spatio‐temporal home range overlap) of animals is important for many questions regarding behavioural ecology, wildlife management and conservation. The current methods that calculate joint space use generally do not account for proximity in space use, as all of them rely on the differences between the exact spatial overlay of utilization distributions, while spatial distances between distributions should be considered to truly quantify similarity.

We implemented the earth mover's distance (EMD), a spatially explicit method, that quantifies similarity between utilization distributions by calculating the effort it takes to shape one utilization distribution landscape into another, hence EMD.

The EMD is a method commonly used in image retrieval applications, and we propose its use to calculate similarity in space use in the framework of movement ecology.

We show that the EMD is a consistent and useful as well as versatile measure of overlap and provide an easy to use implementation in the r package move.
A novel stereo‐video method to investigate fish–habitat relationships
Authors: Collins Danielle L. , Langlois Tim J. , Bond Todd , Holmes Thomas H. , Harvey Euan S. , Fisher Rebecca , McLean Dianne L. 
Published: August 2016

Summary

Habitat complexity is known to influence the structure of fish assemblages. A number of techniques have previously been used to measure complexity, including quantitative in situ methods, which can be time‐consuming and labour‐intensive, and more rapid semi‐quantitative visual scoring methods. This study investigated the utility of a novel method for estimating complexity, whereby habitat height was measured using stereo‐photogrammetry from diver‐operated stereo‐video, traditionally used to sample fish assemblages.

This ‘stereo‐height’ method was compared to established in situ and visual scoring techniques and found to produce similar estimates of complexity. To determine how relevant the proposed method is for assessing ecological relationships, it was then used in conjunction with visual scoring of relief and point‐intercept samples of benthic composition to model fish–habitat associations in the Pilbara region of Western Australia.

Visual scores of relief were marginally stronger predictors of fish assemblage parameters and functional groups than the stereo‐height measurements, providing support for the visual scoring approach. The only exception was for corallivorous fishes, which were more strongly correlated with stereo‐height measurements. This study has presented a method for assessing habitat complexity using video imagery that is both comparable to traditional in situ techniques and useful for investigating fish–habitat relationships.

We suggest that future studies interested in collecting habitat complexity data from new or existing stereo‐video samples use both the stereo‐height and visual scoring methods presented here. Together these methods enable studies to rapidly and effectively assess fish–habitat relationships across a range of habitats without the need for in situ methods or solely relying on field observers trained in visual scoring techniques.
Depression, marijuana use and early‐onset marijuana use conferred unique effects on neural connectivity and cognition
Authors: Osuch E. A. , Manning K. , Hegele R. A. , Théberge J. , Neufeld R. , Mitchell D. , Williamson P. , Gardner R. C. 
Published: August 2016

ObjectiveMarijuana (MJ) use is common. Research shows risks for psychiatric illnesses, including major depressive disorder (MDD) and cognitive deficits with MJ use, particularly early‐onset use. We investigated cognitive function, functional connectivity, and genetic risk with MDD alone and combined with MJ use, and differences between early‐vs. late‐onset/non‐MJ use in youth.MethodA total of 74 youth in four groups were studied: healthy control, MDD, frequent MJ use and current/past MDD plus frequent MJ use. Psychiatric symptoms, cognitive performance and demographics were measured. Default mode network (DMN) brain connectivity was determined. Risk alleles in six genes of interest were evaluated.ResultsDMN differences among groups in reward‐processing and motor control regions were found; the effects of MJ use and MDD were distinct. Early‐onset MJ use was associated with lower IQ and hyperconnectivity within areas of the DMN. Early‐onset MJ use was associated with the BDNF risk allele.ConclusionsCognitive deficits linked with early‐onset MJ use were present within several years after MJ use began and may result from, predispose to, or share a common cause with early‐onset MJ use. The DMN was affected by MDD, MJ and their combination, as well as by early‐onset MJ use. BDNF carrier state may predispose to early‐onset MJ use.
Alcohol marketing and youth alcohol consumption: a systematic review of longitudinal studies published since 2008
Authors: Jernigan David , Noel Jonathan , Landon Jane , Thornton Nicole , Lobstein Tim 
Published: August 2016

AbstractBackground and AimsYouth alcohol consumption is a major global public health concern. Previous reviews have concluded that exposure to alcohol marketing was associated with earlier drinking initiation and higher alcohol consumption among youth. This review examined longitudinal studies published since those earlier reviews.MethodsPeer‐reviewed papers were identified in medical, scientific and social science databases, supplemented by examination of reference lists. Non‐peer‐reviewed papers were included if they were published by organizations deemed to be authoritative, were fully referenced and contained primary data not available elsewhere. Papers were restricted to those that included measures of marketing exposure and alcohol consumption for at least 500 underage people. Multiple authors reviewed studies for inclusion and assessed their quality using the National Heart, Lung and Blood Institute's Quality Assessment Tool for Observation Cohort and Cross‐Sectional Studies.ResultsTwelve studies (ranging in duration from 9 months to 8 years), following nine unique cohorts not reported on previously involving 35 219 participants from Europe, Asia and North America, met inclusion criteria. All 12 found evidence of a positive association between level of marketing exposure and level of youth alcohol consumption. Some found significant associations between youth exposure to alcohol marketing and initiation of alcohol use (odds ratios ranging from 1.00 to 1.69), and there were clear associations between exposure and subsequent binge or hazardous drinking (odds ratios ranging from 1.38 to 2.15). Mediators included marketing receptivity, brand recognition and alcohol expectancies. Levels of marketing exposure among younger adolescents were similar to those found among older adolescents and young adults.ConclusionsYoung people who have greater exposure to alcohol marketing appear to be more likely subsequently to initiate alcohol use and engage in binge and hazardous drinking.
Effectiveness of pharmacy‐based needle/syringe exchange programme for people who inject drugs: a systematic review and meta‐analysis
Authors: Sawangjit Ratree , Khan Tahir Mehmood , Chaiyakunapruk Nathorn 
Published: August 2016

AbstractAimsTo appraise the evidence critically for effectiveness of pharmacy‐based needle/syringe exchange programmes (pharmacy‐based NSPs) on risk behaviours (RBs), HIV/HCV prevalence and economic outcomes among people who inject drugs (PWID).DesignSystematic review and meta‐analysis.SettingPrimary care setting.ParticipantsOf 1568 studies screened, 14 studies with 7035 PWID were included.MeasuresPubMed, Embase, Web of Sciences, CENTRAL and Cochrane review databases were searched without language restriction from their inception to 27 January 2016. All published study designs with control groups that reported the effectiveness of pharmacy‐based NSP on outcomes of interest were included. Outcomes of interest are risk behaviour (RB), HIV/hepatitis C virus (HCV) prevalence and economic outcomes. The estimates of pooled effects of these outcomes were calculated as pooled odds ratio (OR) with 95% confidence interval (CI) using a random‐effects model. Heterogeneity was assessed by I2 and χ2 tests.FindingsMost studies (nine of 14, 64.3%) were rated as having a serious risk of bias, while 28.6 and 7.1% were rated as having a moderate risk and low risk of bias, respectively. For sharing‐syringe behaviour, pharmacy‐based NSPs were significantly better than no NSPs for both main (OR = 0.50, 95% CI = 0.34–0.73; I2 = 59.6%) and sensitivity analyses, excluding studies with a serious risk of bias (OR = 0.52, 95% CI = 0.32–0.84; I2 = 41.4%). For safe syringe disposal and HIV/HCV prevalence, the evidence for pharmacy‐based NSPs compared with other NSP or no NSP was unclear, as few of the studies reported this and most of them had a serious risk of bias. Compared with the total life‐time cost of US$55 640 for treating a person with HIV infection, the HIV prevalence among PWID has to be at least 0.8% (for pharmacy‐based NSPs) or 2.1% (for other NSPs) to result in cost‐savings.ConclusionsPharmacy‐based needle/syringe exchange programmes appear to be effective for reducing risk behaviours among people who inject drugs, although their effect on HIV/HCV prevalence and economic outcomes is unclear.
Differential expression of apolipoprotein D in male reproductive system of rats by high‐fat diet
Authors: Lim W. , Bae H. , Song G. 
Published: August 2016

SummaryApolipoprotein D, a 29‐kDa secreted glycoprotein that belongs to the lipocalin superfamily, is widely expressed in various tissues and associated with lipid metabolism as a component of high‐density lipoproteins. Although Apolipoprotein D binds to small hydrophobic ligands including cholesterol, little is known about effects of high‐fat diet with cholesterol on expression of Apolipoprotein D in the male reproductive tract. Therefore, we investigated Apod expression in penises, prostate glands, and testes from rats fed a high‐fat diet including a high amount of cholesterol. Our previous research indicated that a high‐fat diet induces dyslipidemia leading to histological changes and dysfunction of male reproduction in rats. Consistent with these results, Apod mRNA expression was significantly (p < 0.001) decreased in penises and prostate glands (p < 0.01) and testes (p < 0.01) from rats fed a high‐fat diet as compared with normal diet. In addition, Apod mRNA and protein were detected predominantly in urethral epithelium and penile follicle from rats. Moreover, changes in expression of specific microRNAs (miR‐229b‐3p, miR‐423‐3p, and miR‐490‐3p) regulating Apod in the penises and prostate glands were negatively associated with Apod expression. Collectively, results of this study suggest that Apod is a novel regulatory gene in the male reproductive system, especially in penises of rats fed a high‐cholesterol diet, and that expression of Apod is regulated at the posttranscriptional level by target microRNAs.
Nicotinamide phosphoribosyltransferase production in human spermatozoa is influenced by maturation stage
Authors: Riammer S. , Garten A. , Schaab M. , Grunewald S. , Kiess W. , Kratzsch J. , Paasch U. 
Published: August 2016

SummaryHigh amounts of nicotinamide phosphoribosyltransferase (NAMPT) were found in human seminal plasma. This enzyme influences energy metabolism and apoptosis and is essential for the regulation of cellular nicotinamide adenine dinucleotide (NAD)+ levels in somatic cells. NAD+ is required as a co‐substrate for dehydrogenases, which are potentially important for spermatogenesis. The functional significance of intra‐ and extracellular NAMPT in human reproduction, however, has not been defined yet. The objectives of the study were therefore to determine NAMPT protein expression in human spermatozoa and testes, the secretion of NAMPT by spermatozoa depending on their maturation stage and the impact of NAMPT enzymatic function on sperm viability, motility, fertilisation capacity and induction of apoptosis. Firstly, we detected NAMPT protein in different cell types of human testes. NAMPT protein was also detected in spermatozoa, with significantly higher amounts in immature than in mature ejaculated spermatozoa. Additionally, NAD+ levels were significantly higher in immature than in mature spermatozoa. Secondly, NAMPT was released into the supernatant of human spermatozoa, with significantly higher NAMPT levels in supernatant of immature spermatozoa compared with mature cells. Finally, the specific inhibition of the enzyme by FK866 did not influence motility, capacitation or apoptosis signalling. In summary, NAMPT is produced in human spermatozoa in a maturation‐dependent manner.
Beneficial effects of microsurgical varicocoelectomy on sperm maturation, DNA fragmentation, and nuclear sulfhydryl groups: a prospective trial
Authors: Alhathal N. , San Gabriel M. , Zini A. 
Published: August 2016

SummaryThere is evidence to show that varicocele repair can improve conventional sperm parameters but the effects on sperm chromatin integrity have not been fully elucidated. We sought to examine the effects of varicocelectomy on sperm maturation, nuclear chromatin integrity and nuclear sulfhydryl groups. We conducted a prospective study of consecutive infertile men (n=29) that underwent a microsurgical sub‐inguinal varicocelectomy for treatment of a clinically palpable varicocele and abnormal semen parameters. Six healthy sperm donors served as controls. We evaluated conventional sperm parameters and markers of sperm chromatin and DNA integrity (aniline blue (AB) staining, iodoacetamide fluorescein (IAF) fluorescence and, % DNA fragmentation index (%DFI) and percent high DNA stainability (%HDS) by sperm chromatin structure assay) before and 6 months after surgery. The sperm %DFI, %HDS, % 5‐IAF staining (diffuse head staining) and % AB staining (dark blue) were all significantly lower in the control group compared to infertile men with varicocele (8 vs. 20%, 4.0 vs. 9.6%, 1.7 vs. 16.3%, and 2.5 vs. 13.5% respectively). The %HDS and %DFI decreased significantly after surgery (from 10% to 6% and from 20% to 13%, respectively). Similarly, the %5‐IAF and %AB staining also decreased significantly after surgery (from 16.3% to 5.4%, and from 13.5% to 5.4%, respectively). We observed significant inversely relationships between sperm progressive motility and both %IAF staining and %DFI (r=−0.44 and −0.43, respectively). The data show that varicocelectomy is associated with an improvement in sperm DNA integrity and chromatin compaction using three different assays of sperm chromatin integrity.