bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interannual variability in responses of belowground net primary productivity (NPP) and NPP partitioning to long‐term warming and clipping in a tallgrass prairie
Authors: Xu Xia , Niu Shuli , Sherry Rebecca A. , Zhou Xuhui , Zhou Jizhong , Luo Yiqi 
Published: January 2012

AbstractThe dynamics of belowground net primary productivity (BNPP) is of fundamental importance in understanding carbon (C) allocation and storage in grasslands. However, our knowledge of the interannual variability in response of BNPP to ongoing global warming is limited. In this study, we explored temporal responses of BNPP and net primary productivity (NPP) partitioning to warming and clipping in a tallgrass prairie in Oklahoma, USA. Infrared heaters were used to elevate soil temperature by approximately 2 °C since November 1999. Annual clipping was to mimic hay harvest. On average from 2005 to 2009, warming increased BNPP by 41.89% in the unclipped subplots and 66.93% in the clipped subplots, with significant increase observed in wet years. Clipping also had significant positive impact on BNPP, which was mostly found under warming. Overall, fBNPP, the fraction of BNPP to NPP, increased under both warming and clipping treatments, more in dry years. Water availability (either precipitation or soil moisture) was the most limiting factor for both BNPP and fBNPP. It strongly dominated the interannual variability in NPP, fBNPP, and their responses to warming and clipping. Our results suggest that water availability regulates tallgrass prairie's responses to warming and land use change, which may eventually influence the global C cycle. With increasing variability in future precipitation patterns, warming effects on the vegetation in this region may become less predictable.
Response of butterflies to structural and resource boundaries
Authors: Schultz Cheryl B. , Franco Aldina M. A. , Crone Elizabeth E. 
Published: January 2012

Summary1. Two aspects of landscape composition shape the behavioural response of animals to habitat heterogeneity: physical habitat structure and abundance of key resources. In general, within‐habitat movement behaviour has been investigated in relation to resources, and preference at boundaries has been quantified in response to physical structure.2. Habitat preference studies suggest that responses to resources vs. structure should differ, e.g. between male and female animals, and effects of responses to structure and resources may also interact. However, most studies of animal movement combine various aspects of behavioural responses to ‘habitat’, implicitly assuming that resources and structure are broadly equivalent.3. We conducted a large‐scale experiment of the movement of Fender’s blue (Icaricia icarioides fenderi), an endangered butterfly, to investigate butterfly response to physical structure of the landscape (prairie, open woods and dense woods) and to resources [presence or absence of Kincaid’s lupine, Lupinus oreganus (larval hostplant patches)]. The experiment included 606 butterfly flight paths across four habitat types and nine ecotones.4. Responses to physical structure and resource patches were not congruent. Butterflies were attracted to resource patches within both prairies and open woods and moved more slowly when in resource patches. Butterflies tended to prefer prairie at prairie‐forest edges but tended to move faster in prairies than in open woods. Physical structure and resources also interacted; butterflies did not respond to physical habitat structure when resource patches spanned prairie – open woods ecotones.5. Even dense woods were not perfect barriers, in contrast to a large body of literature that assumes insects from open habitats will not enter dense forests.6. Movement of both males and females responded to resources and structure. However, female butterflies had stronger responses to both resources and structure in most cases. Females had strongest response to resource (hostplant) patches at patch edges, whereas the strongest preference of males was to return to prairie from open forest.7. If other species behave like Fender’s blue, then combining different definitions of ‘habitat’ (physical structure vs. resources), different aspects of movement (edge preference vs. within‐habitat movement) and/or males and females within species could all lead to misleading conclusions. Our results highlight the importance of investigating these responses, and our study provides a framework for separating them in other systems.
Habitat use throughout migration: linking individual consistency, prior breeding success and future breeding potential
Authors: Hoye Bethany J. , Hahn Steffen , Nolet Bart A. , Klaassen Marcel 
Published: January 2012

Summary1. Habitat use can influence individual performance in a wide range of animals, either immediately or through carry‐over effects in subsequent seasons. Given that many animal species also show consistent individual differences in reproductive success, it seems plausible that individuals may have consistent patterns of habitat use representing individual specializations, with concomitant fitness consequences.2. Stable‐carbon isotope ratios from a range of tissues were used to discern individual consistency in habitat use along a terrestrial–aquatic gradient in a long‐distance migrant, the Bewick’s swan (Cygnus columbianus bewickii). These individual specialisations represented <15% of the isotopic breadth of the population for the majority of individuals and were seen to persist throughout autumn migration and overwintering until aquatic habitats were no longer available.3. Individual foraging specialisations were then used to demonstrate two consecutive carry‐over effects associated with macroscale habitat segregation: consequences of breeding season processes for autumn habitat use; and consequences of autumn habitat use for future reproductive success. Adults that were successful breeders in the year of capture used terrestrial habitats significantly more than adults that were not successful, revealing a substantial cost of reproduction and extended parental care. Use of aquatic habitats during autumn was, however, associated with increased body condition prior to spring migration; and increased subsequent breeding success in adults that had been unsuccessful the year before. Yet adults that were successful breeders in the year of capture remained the most likely to be successful the following year, despite their use of terrestrial habitats.4. Our results uniquely demonstrate not only individual foraging specializations throughout the migration period, but also that processes during breeding and autumn migration, mediated by individual consistency, may play a fundamental role in the population dynamics of long‐distance migrants. These findings, therefore, highlight the importance of long‐term consistency to our understanding of habitat function, interindividual differences in fitness, population dynamics and the evolution of migratory strategies.
Successional trends in Floristic Quality
Authors: Spyreas Greg , Meiners Scott J. , Matthews Jeffrey W. , Molano‐Flores Brenda 
Published: January 2012

Summary1. Simple, conservation‐relevant, plant community measures are sought by resource managers. In this context, the use of Floristic Quality Assessment (FQA) has increased exponentially over the past 30 years. FQA measures a habitat’s Floristic Quality and conservation value by summarizing the relative anthropogenic disturbance tolerances of its plant species (i.e. their Conservatism). However, despite their widespread use in research, restoration and conservation work, the behaviour of FQA values in communities during succession is not understood.2. We analysed FQA values in 10 old fields over 50 years of unaltered succession. We determined whether Floristic Quality followed a predictable increasing successional trend, assessing four specific predictions: (i) FQA values will follow an asymptotically increasing, rather than peaked or linearly increasing trajectory; (ii) field initiation treatments (abandoned as hayfield or cropfield) will not lead to long‐term differences in FQA values; (iii) trajectories will be consistent regardless of the particular species composition of fields and (iv) trajectories will be robust to common variations in FQA metric formulations (non‐native species, varied spatial scale).3. In all cases, a negative exponential rise to an asymptote best described FQA value trajectories over time. Field abandonment treatments did not affect FQA value trajectories. Furthermore, trends were consistent among fields despite differences in species composition among fields. Overall, the results suggest a predictable, deterministic path for FQA values over the early‐ to mid‐successional timeframes studied.4. Synthesis and applications. Understanding the temporal behaviour(s) of Floristic Quality is necessary for setting realistic restoration goals, evaluating habitat recovery and adapting management to achieve high conservation value natural areas. By illustrating the temporal consistency of Floristic Quality metrics during succession, this article demonstrates the robustness of FQA for such uses. The FQA value trajectory described here also establishes a background trend model for expected values in recovering habitats, which will allow for the assessment of an individual habitat’s progression relative to the background trend. Such comparisons en masse will highlight the constraints of greatest importance to community‐level Floristic Quality restoration. For example, FQA values in this study were ultimately limited by Conservative understorey plant re‐establishment from adjacent old‐growth forest. As this is not unlike species recovery patterns observed in other habitats, it suggests that restoration practitioners would do well to focus on Conservative species.
Utility of Genome‐Wide Association Study findings: prostate cancer as a translational research paradigm
Authors: Turner A. R. , Kader A. K. , Xu J. 
Published: January 2012

Abstract.  Turner AR, Kader AK, Xu J (Wake Forest University, Winston‐Salem, NC; and University of California San Diego, La Jolla, CA; USA). Utility of Genome‐Wide Association Study findings: prostate cancer as a translational research paradigm (Review). J Intern Med 2012; 271: 344–352.Genome‐Wide Association Studies have identified thousands of consistently replicated associations between genetic markers and complex disease risk, including cancers. Alone, these markers have limited utility in risk prediction; however, when several of these markers are used in combination, the predictive performance appears to be similar to that of many currently available clinical predictors. Despite this, there are divergent views regarding the clinical validity and utility of these genetic markers in risk prediction. There are valid concerns, thus providing a direction for new lines of research. Herein, we outline the debate and use the example of prostate cancer to highlight emerging evidence from studies that aim to address potential concerns. We also describe a translational framework that could be used to guide the development of a new generation of comprehensive research studies aimed at capitalizing on these exciting new discoveries.
New(t)s and views from hybridizing MHC genes: introgression rather than trans‐species polymorphism may shape allelic repertoires
Authors: WEGNER K. MATHIAS , EIZAGUIRRE CHRISTOPHE 
Published: January 2012

One of the key features of major histocompatibility complex (MHC) genes is the frequent occurrence of trans‐species polymorphism, that is ‘the passage of allelic lineages from ancestral to descendant species’ (Klein et al. 2007). Selectively maintained ancestral polymorphism may, however, be hard to distinguish from introgression of MHC alleles between hybridizing species (Fig. 1). In this issue of Molecular Ecology, Nadachowska‐Brzyska et al. (2012) present data that suggest that the latter can be observed in two closely related species of newts, Lissotriton vulgaris (Lv) and L. montandoni (Lm) from south‐east Europe. Strikingly, allelic MHC variation displayed more structure between geographically separated populations of L. vulgaris than across species in the hybrid zone. This suggests that high MHC variation in L. montadoni may result from mainly unidirectional gene flow between species, while differentiation between northern and southern populations of L. vulgaris might reflect local adaptation. Potential mechanisms generating shared repertoires of major histocompatibility complex alleles between southeast European newt species: Trans‐species polymorphism (left side) maintaining ancestral polymorphism across speciation events and introgression (right side) where alleles arising in one species after speciation introgress into the other by hybridization. The study Nadachowska‐Brzyska et al. 2012 suggests that the latter can be observed in two closely related newt species. Photos by Benny Trapp and Magdalena Herdegen.image
Genotype × environment interaction, environmental heterogeneity and the lek paradox
Authors: GREENFIELD M. D. , DANKA R. G. , GLEASON J. M. , HARRIS B. R. , ZHOU Y. 
Published: January 2012

AbstractSubstantial additive genetic variance (VA) often exists for male signalling traits in spite of the directional selection that female choice imposes. One solution to this problem, a conundrum generally termed the ‘lek paradox’, is that genotype × environment interaction (GEI) occurs and generates a ‘crossover’ of reaction norms in which no one genotype performs in a superior manner in all environments. Theoretical work indicates that such crossover can sustain genetic variance provided that either (i) spatial heterogeneity in environmental conditions combined with limited migration among populations or (ii) temporal heterogeneity in environmental conditions combined with occasional generation overlap is present. Whereas some recent studies have revealed the intersection of reaction norms for sexually selected traits in laboratory and in natural populations, associated information on environmental heterogeneity, migration and generation overlap has not been investigated. We studied this question in an acoustic pyralid moth,Achroia grisella, in which previous work indicated GEI and crossover of reaction norms for several parameters of the male song evaluated by females. We measured reaction norms for male song as expressed when development was completed under different environmental conditions in four neighbouring, yet isolated, populations during 1 year and in one of these populations during consecutive years. Crossover occurred for the various song parameters in the several populations, but we did not observe a higher incidence of crossover between genotypes taken from two different populations than from the same population. However, for several key song parameters, crossover between genotypes taken from two different years was higher than that between genotypes from the same year. We suggest that temporal heterogeneity in the form of varying selection could potentially conserve VAinA. grisella, but we also note other factors that might contribute.
Is the physical functioning of older adults with diabetes associated with the processes and outcomes of care? Evidence from Translating Research Into Action for Diabetes (TRIAD)
Authors: Lee P. G. , McEwen L. N. , Waitzfelder B. , Subramanian U. , Karter A. J. , Mangione C. M. , Herman W. H. 
Published: January 2012

Diabet. Med. 29, e321–e325 (2012)AbstractAims  To examine the relationship between physical function limitations and diabetes self‐management, processes of care and intermediate outcomes in adults ≥ 65 years of age with Type 2 diabetes.Methods  We studied 1796 participants 65 years of age and older in managed care health plans enrolled in Translating Research into Action for Diabetes (TRIAD). Physical functioning was assessed at baseline with the Physical Component Summary of the Short Form‐12 Health Survey. Diabetes self‐management was assessed with follow‐up surveys, and processes of care (eye examinations, urine microalbumin testing, foot examinations, etc.) and intermediate health outcomes (HbA1c, blood pressure, LDL cholesterol) were assessed with medical chart reviews. Multivariate regression models were constructed to examine the associations between physical function limitations and outcomes.Results  Frequency of eye examinations (odds ratio 0.69, 95% CI 0.49–0.99) was the only process of care that was worse for participants with physical function limitations (n = 573) compared with those without limitations (n = 618). Neither self‐management nor intermediate outcomes differed by whether patients had or did not have physical function limitations.Conclusion  Limitations in physical functioning as assessed by the Short Form‐12 were not associated with substantial difference in diabetes care in adults ≥ 65 years of age enrolled in managed care health plans.
Hyperbaric oxygen therapy improves peripheral insulin sensitivity in humans
Authors: Wilkinson D. , Chapman I. M. , Heilbronn L. K. 
Published: January 2012

Diabet. Med. 29, 986–989 (2012)AbstractAim  Hyperbaric oxygen therapy is known to reduce fasting blood glucose in individuals with Type 2 diabetes. However, the mechanisms of this effect are not clear. The aim of this study was to determine whether peripheral insulin sensitivity by hyperinsulinaemic euglycaemic clamp is increased in patients presenting for hyperbaric oxygen therapy.Methods  Participants were non‐obese individuals without Type 2 diabetes (n = 5) or obese patients with Type 2 diabetes (n = 5). Patients were given 100% oxygen at 2.0 absolute atmospheres for 2 h, six sessions per week for 5 weeks.Results  Peripheral insulin sensitivity was increased in the whole cohort (P = 0.04). Subsequent analysis revealed that this was significant at both treatment 3 (+37.3 ± 12.7%, P = 0.02) and treatment 30 (+40.6 ± 12.6%, P = 0.009). HbA1c was significantly reduced in subjects without diabetes only (P < 0.05).Conclusion  Insulin sensitivity increased within 3 days of hyperbaric oxygen treatment and this was maintained for 30 sessions. This increase in insulin sensitivity is equivalent to that observed following moderate weight loss. The mechanisms underlying the insulin‐sensitizing effect of hyperbaric oxygen require further elucidation.
HbA1c and glucose intolerance in obese children and adolescents
Authors: Lee H. S. , Park H. K. , Hwang J. S. 
Published: January 2012

Diabet. Med. 29, e102–e105 (2012)AbstractAims  Childhood obesity is associated with an increased likelihood for having impaired glucose tolerance, dyslipidaemia and diabetes. The aim of the study was to evaluate HbA1c as a screening test for impaired glucose tolerance in obese children and adolescents and identify the optimal HbA1c threshold.Methods  We studied 126 obese and overweight children (BMI > 85th percentile for age and gender) 4–17 years of age referred to the endocrine clinic at Ajou University Hospital in Korea. All subjects underwent HbA1c and oral glucose tolerance test.Results  Thirty‐four patients (27%) out of 126 had impaired glucose tolerance. Silent diabetes was diagnosed in 10 adolescents (7.9%). Based on the receiver operating characteristic curve, the optimal cut point of HbA1c related to impaired glucose tolerance diagnosed by oral glucose tolerance test was 40 mmol/mol (5.8%), which was associated with a 64.7% sensitivity and 61.6% specificity, with an area under the receiver operating characteristic curve of 0.651 (95% CI 0.529–0.772).Conclusions  Obesity is associated with an increased risk of impaired glucose tolerance. An HbA1c value of 40 mmol/mol (5.8%) should be used as a screening tool to identify children and adolescents with impaired glucose tolerance.
Movement and habitat use of Australia's largest snake‐necked turtle: implications for water management
Authors: Bower D. S. , Hutchinson M. , Georges A. 
Published: January 2012

AbstractHydrological regimes strongly influence ecological processes in river basins. Yet, the impacts of management regimes are unknown for many freshwater taxa in highly regulated rivers. We used radio‐telemetry to monitor the movement and activity of broad‐shelled river turtles Chelodina expansa to infer the impact of current water management practices on turtles in Australia's most regulated river – the Murray River. We radio‐tracked C. expansa to (1) measure the range span and examine the effect of sex, size and habitat type on turtle movement, and (2) examine habitat use within the river channel and its associated backwaters. C. expansa occupied all macro habitats in the river (main channel, backwater, swamp and connecting inlets). Within these habitats, females occupied discrete home ranges, whereas males moved up to 25 km. The extensive movement of male turtles suggests that weirs and other aquatic barriers may interfere with movement and dispersal. Turtles regularly move between backwaters and the main river channel, which highlights the likely disturbance from backwater detachment, a water saving practice in the lower Murray River.
Is spatial variation in food availability an explanation for aBergmannian size pattern in aNorthAmerican hibernating, burrowing mammal? An information‐theoretic approach
Authors: Gür H. , Kart Gür M. 
Published: January 2012

AbstractPredictable empirical patterns of variation in body size along spatial and environmental gradients have been documented within many species of mammals. Four main hypotheses, heat conservation, heat dissipation, primary productivity and seasonality, have been proposed to explain these patterns of variation in body size. In this study, we reported an analysis of geographic variation in body size of Richardson's ground squirrelsUrocitellus richardsonii, aNorthAmerican hibernating, burrowing mammal. Firstly, we evaluated whether aBergmannian size pattern was exhibited by Richardson's ground squirrels. Secondly, we used an information‐theoretic approach to test which of the four main hypotheses best explain(s) geographic variation in body size of Richardson's ground squirrels or to assess whether, as proposed byMcNab's ‘resource rule’ orHuston andWolverton's ‘eNPPrule’, the primary productivity hypothesis is the only explanation.Richardson's ground squirrels exhibited a pattern of increasing body size towards the colder areas, that is, more productive and seasonal centralAlberta and foothills of the southernAlbertaRockyMountains, indicative of aBergmannian size pattern. Plant productivity and seasonality in plant productivity were likely the primary underlying factors generating the observed pattern of geographic variation in body size. Thus, our results supported primary productivity and seasonality hypotheses. From these results, we see thatMcNab's ‘resource rule’ orHuston andWolverton's ‘eNPPrule’ (i.e. spatial variation in food availability) is an explanation for aBergmannian size pattern inRichardson's ground squirrels, but not the only explanation.