bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two‐colour chewing gum mixing ability: digitalisation and spatial heterogeneity analysis
Authors: Weijenberg R. A. F. , Scherder E. J. A. , Visscher C. M. , Gorissen T. , Yoshida E. , Lobbezoo F. 
Published: August 2013

SummaryMany techniques are available to assess masticatory performance, but not all are appropriate for every population. A proxy suitable for elderly persons suffering from dementia was lacking, and a two‐colour chewing gum mixing ability test was investigated for this purpose. A fully automated digital analysis algorithm was applied to a mixing ability test using two‐coloured gum samples in a stepwise increased number of chewing cycles protocol (Experiment 1: n = 14; seven men, 19–63 years), a test–retest assessment (Experiment 2: n = 10; four men, 20–49 years) and compared to an established wax cubes mixing ability test (Experiment 3: n = 13; 0 men, 21–31 years). Data were analysed with repeated measures anova (Experiment 1), the calculation of the intraclass correlation coefficient (ICC; Experiment 2) and Spearman's rho correlation coefficient (Experiment 3). The method was sensitive to increasing numbers of chewing cycles (F5,65 = 57·270, P = 0·000) and reliable in the test–retest (ICC value of 0·714, P = 0·004). There was no significant correlation between the two‐coloured gum test and the wax cubes test. The two‐coloured gum mixing ability test was able to adequately assess masticatory function and is recommended for use in a population of elderly persons with dementia.
What do egg size distributions in marine invertebrates tell us about validity of fecundity‐time models?
Authors: Kupriyanova Elena K. 
Published: August 2013

AbstractAn early mathematical model of egg size evolution in marine invertebrates (American Naturalist, 1973a, 107, 353) traded fecundity against development time and resulted in a U‐shaped optimality curve suggesting that only extremes of egg sizes should be evolutionary stable. It was later suggested that the model predicts a bimodal distribution of egg sizes and therefore can be tested by examining histograms of egg sizes. More recent fecundity‐time models (American Naturalist, 1997, 150, 48; American Naturalist, 2000, 156, 175) came up with predictions of intermediate optimal egg sizes; however, comparisons of optimality curves with histograms of egg sizes remained central to model testing. Here the question whether the bimodality assumption has any basis has been addressed theoretically. Simulation modeling and analysis show that egg size distributions generally do not match the optimality curves produced by fecundity‐time models and that the shape of predicted frequency distributions depends on both the optimality curve and other model parameters. Therefore, egg size frequency distributions alone cannot be used for model testing.
Influence of tidal regime, diurnal phase, habitat and season on feeding of an intertidal crab
Authors: Bas Claudia , Lancia Juan P. , Luppi Tomás , Méndez‐Casariego Agustina , Kittlein Marcelo , Spivak Eduardo 
Published: August 2013

AbstractThe relationship between diet and feeding activity of intertidal crabs, and environmental cycles (tidal, daily and seasonal), habitat and level of the intertidal zone (high/low) was studied using Neohelice granulata (Brachyura, Varunidae) as a model. This is a semi‐terrestrial burrowing crab occupying different habitats in the Southwestern Atlantic coasts and estuaries from bare low intertidal mudflats to high intertidal salt marshes, and from fine, organic matter rich sediment to very coarse sediment with low content of organic matter. The study was carried out in two contrasting habitats of three sites with diverse sets of physical and biological conditions. Diet and feeding of adult N. granulata were indirectly studied through the proportion of food items and the presence/absence of food in crab stomachs, respectively. This species has a dual mode of feeding: predominantly herbivorous (live plants or plant litter in salt marshes) or deposit feeder (superficial sediment and detritus in mudflats), but the quantity and quality of ingested food varies among habitats and sites. A trend to omnivory (including algae and conspecifics) was detected in relation to low quality of resources. Feeding activity modulated by a complex interaction of factors varied according to spatial and/or temporal changes in some natural cycles. Males and non‐ovigerous females fed preferably after dark and during submersion periods, but also after emersion periods if mudflat sediment remained wet; salt marsh crab feeding is somewhat independent of light and tidal cycles. Ovigerous females almost never fed. Both diet and feeding activity of this crab seem to be flexible traits adapted to different combinations of physical and biological factors.
Compositional variability on the surface of 4 Vesta revealed through GRaND measurements of high‐energy gamma rays
Authors: Peplowski Patrick N. , Lawrence David J. , Prettyman Thomas H. , Yamashita Naoyuki , Bazell Dave , Feldman William C. , Le Corre Lucille , McCoy Timothy J. , Reddy Vishnu , Reedy Robert C. , Russell Chris T. , Toplis Michael J. 
Published: August 2013

AbstractMeasurements of the high‐energy gamma‐ray flux emanating from asteroid 4 Vesta by the Dawn Gamma‐Ray and Neutron Detector (GRaND) have revealed variability in the near‐surface elemental composition of the Vestan surface. These observations are consistent with the presence of large (≥8 × 104 km2) regions with distinct, HED‐like elemental compositions. The results agree broadly with other global measurements, such as the macroscopic neutron absorption cross section and spectral reflectance‐derived mineralogic maps. Two distinct regions with eucrite‐like elemental compositions have been identified, the first located primarily within the Lucaria and Marcia quadrangles and the second within Oppia quadrangle. The former region is collocated with some of the oldest, most heavily cratered terrain on Vesta. The interior of the 500 km diameter Rheasilvia impact basin is found to have a composition that is consistent with diogenite‐like material. Taken together, these observations support the hypothesis that Vesta's original crust was composed of basaltic outflows in the form of eucritic‐like material and that the Rheasilvia‐basin‐forming impact exposed lower‐crustal, diogenite‐like material. These measurements also constrain the maximum amount of mesosiderite‐like material to <10% for each 15 × 15° surface element.
Phylogeography of Sophora davidii (Leguminosae) across the ‘Tanaka‐Kaiyong Line’, an important phytogeographic boundary in Southwest China
Authors: Fan Deng Mei , Yue Ji Pei , Nie Ze Long , Li Zhi Min , Comes Hans Peter , Sun Hang 
Published: August 2013

AbstractThe ‘Tanaka‐Kaiyong Line’ (TKL) is a major phytogeographic boundary in Southwest China, separating East Asia's Sino‐Himalayan and Sino‐Japanese Floras. However, little is known about the importance of this boundary in promoting intraspecific phylogeographic subdivision and divergence. Using chloroplast (cpDNA) and nuclear‐intron (nDNA) sequence data, we reconstructed the population history of Sophora davidii, a drought‐tolerant riparian shrub widely distributed on either side of the TKL. Specifically, we aimed at testing two long‐standing explanations for possible vicariant events across the TKL: (i) Late Pliocene (c. 3 Ma) geological uplift of the eastern Qinghai‐Tibetan Plateau (QTP) or (ii) a sharp environmental gradient associated with the establishment of different monsoon regimes on either side of the TKL during the (Late) Pleistocene. Our genealogical analyses detected a major west–east split in cpDNA, geographically largely consistent with the TKL, and dated to c. 1.28 Ma (95% HPD: 0.21–2.96 Ma), hence postdating the latest phase of eastern QTP uplift. Furthermore, integrating cpDNA phylogeographic patterns with mismatch analyses, we found multiple refugial isolation and long‐term demographic stability of populations in the west (Hengduan Mountain Range) compared with extensive range expansions in the east, possibly during the last glacial period(s) and followed by differentiation into regional sublineages (southeast: Yunnan‐Guizhou Plateau vs. northeast: Qinling Mts./Loess Plateau). Although nuclear differentiation was less marked, the geographical pattern of nDNA haplotypes provided some further indication of the species' eastward expansion, possibly from source populations located just east of the TKL (lower Jinshajiang region). Overall, the present data reject the geological (tectonic) explanation for the TKL and, instead, provide supportive evidence for its role as a climatically driven barrier to present‐day plant dispersal. In addition, our study highlights changing temperatures and vegetation types during the last glacial period(s), along with aspects of regional topography, to be important determinants of the glacial eastward expansion of S. davidii. In consequence, our study lends support to a ‘glacial out‐of‐Hengduan Mts’. hypothesis for the xerophytic‐riparian flora of Southwest China, which in turn is inconsistent with the traditional view of the TKL as a ‘classical’ vicariant‐biogeographic boundary.
Evidence for selective sweeps by Wolbachia infections: phylogeny of Altica leaf beetles and their reproductive parasites
Authors: Jäckel Regina , Mora Diana , Dobler Susanne 
Published: August 2013

AbstractInfections with maternally inherited Wolbachia bacteria may have dramatic influences on reproductive traits and speciation patterns of their hosts. We here show that in the beetle genus Altica, infection has influenced phylogenetic patterns of the host's mtDNA and different strains led to repeated selective sweeps. By comparing a COI/II‐based phylogeny of the hosts with a phylogeny of the bacteria based on ftsZ, we show that cospeciation is rare and restricted to few recently diverged species. While in general each species apparently harbours a single Wolbachia strain, Altica lythri presents a strikingly different pattern: in the polyphyletic species, three highly divergent mtDNA haplotypes (2.1–4.6% p‐distance) are coupled with three different Wolbachia strains (wLytA1, wLytA2 and wLytB). These haplotypes and Wolbachia strains are widely distributed and mostly found in sympatry. A phylogeny based on microsatellite data supports the monophyly of A. lythri. The discrepancy between mtDNA and nuclear phylogeny may best be explained by interspecific hybridization that led to introgression of mtDNA coupled with a different Wolbachia strain. Selective sweeps apparently drove the introgressed haplotypes to widespread distribution. As for effects of Wolbachia on reproduction, infection with wLytA1 appears to be correlated with a substantial sex ratio distortion, which was most prominent in A. lythri.
Late‐glacial recolonization and phylogeography of European red deer (Cervus elaphus L.)
Authors: Meiri Meirav , Lister Adrian M. , Higham Thomas F. G. , Stewart John R. , Straus Lawrence G. , Obermaier Henriette , González Morales Manuel R. , Marín‐Arroyo Ana B. , Barnes Ian 
Published: August 2013

AbstractThe Pleistocene was an epoch of extreme climatic and environmental changes. How individual species responded to the repeated cycles of warm and cold stages is a major topic of debate. For the European fauna and flora, an expansion–contraction model has been suggested, whereby temperate species were restricted to southern refugia during glacial times and expanded northwards during interglacials, including the present interglacial (Holocene). Here, we test this model on the red deer (Cervus elaphus) a large and highly mobile herbivore, using both modern and ancient mitochondrial DNA from the entire European range of the species over the last c. 40 000 years. Our results indicate that this species was sensitive to the effects of climate change. Prior to the Last Glacial Maximum (LGM) haplogroups restricted today to South‐East Europe and Western Asia reached as far west as the UK. During the LGM, red deer was mainly restricted to southern refugia, in Iberia, the Balkans and possibly in Italy and South‐Western Asia. At the end of the LGM, red deer expanded from the Iberian refugium, to Central and Northern Europe, including the UK, Belgium, Scandinavia, Germany, Poland and Belarus. Ancient DNA data cannot rule out refugial survival of red deer in North‐West Europe through the LGM. Had such deer survived, though, they were replaced by deer migrating from Iberia at the end of the glacial. The Balkans served as a separate LGM refugium and were probably connected to Western Asia with genetic exchange between the two areas.
Host‐associated genomic differentiation in congeneric butterflies: now you see it, now you do not
Authors: Mikheyev Alexander S. , McBride Carolyn S. , Mueller Ulrich G. , Parmesan Camille , Smee Melanie R. , Stefanescu Constanti , Wee Brian , Singer Michael C. 
Published: August 2013

AbstractEcotypic variation among populations may become associated with widespread genomic differentiation, but theory predicts that this should happen only under particular conditions of gene flow, selection and population size. In closely related species, we might expect the strength of host‐associated genomic differentiation (HAD) to be correlated with the degree of phenotypic differentiation in host‐adaptive traits. Using microsatellite andAmplifiedFragmentLengthPolymorphism (AFLP) markers, and controlling for isolation by distance between populations, we soughtHADin two congeneric species of butterflies with different degrees of host plant specialization. Prior work onEuphydryas edithahad shown strong interpopulation differentiation in host‐adapted traits, resulting in incipient reproductive isolation among host‐associated ecotypes. We show here thatEuphydryas auriniahad much weaker host‐associated phenotypic differentiation. Contrary to our expectations, we detectedHADinEuphydryas aurinia, but not inE. editha. Even within anE. auriniapopulation that fed on both hosts, we found weak but significant sympatricHADthat persisted in samples taken 9 years apart. The finding of significantly strongerHADin the system with less phenotypic differentiation may seem paradoxical. Our findings can be explained by multiple factors, ranging from differences in dispersal or effective population size, to spatial variation in genomic or phenotypic traits and to structure induced by past histories of host‐adapted populations. Other infrequently measured factors, such as differences in recombination rates, may also play a role. Our result adds to recent work as a further caution against assumptions of simple relationships between genomic and adaptive phenotypic differentiation.
Disease defence through generations: leaf‐cutter ants and their symbiotic bacteria
Authors: Woodhams Douglas C. , Brucker Robert M. 
Published: August 2013

Microbial ecology of animals is taking on significance in the modern dialogue for the biology of species. Similar to a nuclear genome, the entire bacterial assemblage maintains an ancestral signal of the host's evolution leading to cophylogeny between the host and the microbes they harbour (Brucker & Bordenstein 2012b). The stability of such associations is of great interest as they provide a means for species to acquire new traits and genetic diversity that their own genomes lack (McFall‐Ngai et al. 2013). The role of gut microbiota, for example, in host health and nutrition is widely recognized and a shared characteristic among animals. The role of bacteria colonizing the outside surfaces of animals is less well understood, but rather than random colonization, these microbes on skin, cuticles, scales and feathers in many cases provide benefits to the host. The symbiosis of leaf‐cutter ants, their fungus gardens and their microbiota is a fascinating and complex system. Whether culture‐independent bacterial diversity on the cuticle of leaf‐cutter ants is high or highly constrained by subcuticular gland secretions is one prominent question. In this issue of Molecular Ecology, Andersen et al. (2013) show that leaf‐cutting ants, Acromyrmex echinatior, maintain a dominant and colony‐specific bacterium called Pseudonocardia on their cuticles (the laterocervical plates in particular). This bacterium is involved in protecting the ants and their fungal gardens from disease. Other fungus‐gardening attine species as well as soil and vegetation can harbour Pseudonocardia. However, it was previously unknown how stable the bacterial strain–ant colony association was through the lifetime of the colony.
COMBINING SOCIAL CAPITAL AND TECHNOLOGY FOR DROUGHT RESILIENCE IN AGRICULTURE
Authors: RANJAN RAM 
Published: August 2013

AbstractIn water‐scarce regions of the world, water‐saving technology adoption augments farm productivity. But so does social capital. In this paper, the issue of ensuring livelihood for farmers through the combined use of social capital and water‐saving technology is modeled in the context of repeated droughts. The model presented here derives optimal resource conservation and accumulation strategies when the farmer must ensure minimum consumption during a set of repeated drought events in the future. Findings indicate that the path to drought resilience presents a complex trade‐off between accumulating one form of capital over another and is influenced by farmers’ wealth and water endowments, level of risk associated with the repeated droughts and the duration of the repeated drought event that the farmer plans to survive. A higher risk of repeated droughts leads to an increase in groundwater conservation efforts but delays technology adoption. Lower water endowments may also delay adoption and reduce social capital, however, a lower social capital or a slow rate of its growth is not a hindrance to adopting water‐saving technology earlier. Finally, social capital evolves to higher levels when farmer is simultaneously faced with a higher level of risks and a longer span of drought events.
Constitutive expression of cell wall invertase genes increases grain yield and starch content in maize
Authors: Li Bei , Liu Hua , Zhang Yue , Kang Tao , Zhang Li , Tong Jianhua , Xiao Langtao , Zhang Hongxia 
Published: August 2013

SummaryGrain size, number and starch content are important determinants of grain yield and quality. One of the most important biological processes that determine these components is the carbon partitioning during the early grain filling, which requires the function of cell wall invertase. Here, we showed the constitutive expression of cell wall invertase–encoding gene from Arabidopsis, rice (Oryza sativa) or maize (Zea mays), driven by the cauliflower mosaic virus (CaMV) 35S promoter, all increased cell wall invertase activities in different tissues and organs, including leaves and developing seeds, and substantially improved grain yield up to 145.3% in transgenic maize plants as compared to the wild‐type plants, an effect that was reproduced in our 2‐year field trials at different locations. The dramatically increased grain yield is due to the enlarged ears with both enhanced grain size and grain number. Constitutive expression of the invertase‐encoding gene also increased total starch content up to 20% in the transgenic kernels. Our results suggest that cell wall invertase gene can be genetically engineered to improve both grain yield and grain quality in crop plants.
A Systematic Review of Studies Performing the Hypo‐Osmotic Swelling Test to Evaluate the Quality of Canine Spermatozoa
Authors: Karger S , Arlt S , Haimerl P , Heuwieser W 
Published: August 2013

ContentsThe hypo‐osmotic swelling test (HOS test) is a simple and inexpensive test to evaluate the functional integrity of sperm cell membranes. According to the existing literature, its simple applicability has turned it into a valuable additional parameter to standard canine semen analysis. In the recent years, much research has been conducted in this field. The aim of this systematic review was to evaluate the quality of published literature in canine reproduction concerning the HOS test. Using two distinguished databases, 38 articles were detected and analysed subsequently according to various aspects, for example study design, population, semen sampling and implementation concerning the HOS test. Although there are numerous articles available, the diagnostic value of the HOS test remains ambiguous. Until now, neither a recognized test protocol nor reliable reference values have been defined. Most of the trials evaluated show serious methodological flaws and therefore do not permit drawing reliable conclusions. According to our results, approximately half of the studies (n = 20) included a sample size of five or less animals. None of the studies examined the inter‐ or intraobserver agreement for the HOS test. Further research is warranted including appropriate statistical methods and a sufficient number of animals to establish a standardized test protocol as well as reliable reference values. Most importantly, it is required to clarify a correlation between the HOS test and the fertilizing capacity to determine the diagnostic value of the HOS test.
Fitting Multilevel Multivariate Models with Missing Data in Responses and Covariates that May Include Interactions and Non-Linear Terms
Authors: Goldstein Harvey , Carpenter James R. , Browne William J. 
Published: August 2013

SummaryThe paper extends existing models for multilevel multivariate data with mixed response types to handle quite general types and patterns of missing data values in a wide range of multilevel generalized linear models. It proposes an efficient Bayesian modelling approach that allows missing values in covariates, including models where there are interactions or other functions of covariates such as polynomials. The procedure can also be used to produce multiply imputed complete data sets. A simulation study is presented as well as the analysis of a longitudinal data set. The paper also shows how existing multiprocess models for handling endogeneity can be extended by the framework proposed.
Re-Engaging with Survey Non-Respondents: Evidence from Three Household Panels
Authors: Watson Nicole , Wooden Mark 
Published: August 2013

SummaryPrevious research into the correlates and determinants of non-response in longitudinal surveys has focused exclusively on why it is that respondents at one survey wave choose not to participate at future waves. This is very understandable if non-response is always an absorbing state, but in many longitudinal surveys, and certainly most household panels, this is not so. Indeed, in these surveys it is normal practice to attempt to make contact with many non-respondents at the next wave. This study differs from previous research by examining re-engagement with previous wave non-respondents. Drawing on data from three national household panels it is found that the re-engagement decision is indeed distinctly different from the decision about continued participation. Further, these differences have clear implications for the way that panel surveys should be administered given the desire to enhance overall response rates.
Optimal Bayesian Sequential Sampling Rules for the Economic Evaluation of Health Technologies
Authors: Pertile Paolo , Forster Martin , Torre Davide La 
Published: August 2013

SummaryWe present a Bayes sequential economic evaluation model for health technologies in which an investigator has flexibility over the timing of a decision to stop carrying out research and to conclude that one technology is preferred to another on cost-effectiveness grounds. We implement the model by using an evaluation of the treatment of bacterial sinusitis and derive approximations of the optimal stopping rule as a function of accumulated sample size. We compare the performance of the model with existing frequentist and Bayes sequential designs and investigate the sensitivity of the stopping rule to changes in the parameters of the model. Our results suggest that accounting for the dynamic nature of experimentation, together with its economic parameters, should lead to greater efficiency in resource allocation within healthcare systems.