bluuebunny/crossref_metadata_2025_split huggingface dataset:
Size‐density scaling in protists and the links between consumer–resource interaction parameters
Authors: DeLong John P. , Vasseur David A. 
Published: July 2012

Summary

Recent work indicates that the interaction between body‐size‐dependent demographic processes can generate macroecological patterns such as the scaling of population density with body size. In this study, we evaluate this possibility for grazing protists and also test whether demographic parameters in these models are correlated after controlling for body size.
We compiled data on the body‐size dependence of consumer–resource interactions and population density for heterotrophic protists grazing algae in laboratory studies. We then used nested dynamic models to predict both the height and slope of the scaling relationship between population density and body size for these protists. We also controlled for consumer size and assessed links between model parameters. Finally, we used the models and the parameter estimates to assess the individual‐ and population‐level dependence of resource use on body‐size and prey‐size selection.
The predicted size‐density scaling for all models matched closely to the observed scaling, and the simplest model was sufficient to predict the pattern. Variation around the mean size‐density scaling relationship may be generated by variation in prey productivity and area of capture, but residuals are relatively insensitive to variation in prey size selection. After controlling for body size, many consumer–resource interaction parameters were correlated, and a positive correlation between residual prey size selection and conversion efficiency neutralizes the apparent fitness advantage of taking large prey.
Our results indicate that widespread community‐level patterns can be explained with simple population models that apply consistently across a range of sizes. They also indicate that the parameter space governing the dynamics and the steady states in these systems is structured such that some parts of the parameter space are unlikely to represent real systems. Finally, predator–prey size ratios represent a kind of conundrum, because they are widely observed but apparently have little influence on population size and fitness, at least at this level of organization.
Climatic stability in the Brazilian Cerrado: implications for biogeographical connections of South American savannas, species richness and conservation in a biodiversity hotspot
Authors: Werneck Fernanda P. , Nogueira Cristiano , Colli Guarino R. , Sites Jack W. , Costa Gabriel C. 
Published: July 2012

AbstractAim  To investigate the historical distribution of the Cerrado across Quaternary climatic fluctuations and to generate historical stability maps to test: (1) whether the ‘historical climate’ stability hypothesis explains squamate reptile richness in the Cerrado; and (2) the hypothesis of Pleistocene connections between savannas located north and south of Amazonia.Location  The Cerrado, a savanna biome and a global biodiversity hotspot distributed mainly in central Brazil.Methods  We generated occurrence datasets from 1000 presence points randomly selected from the entire distribution of the Cerrado, as determined by two spatial definitions. We modelled the potential Cerrado distribution by implementing a maximum‐entropy machine‐learning algorithm across four time projections: current, mid‐Holocene (6 ka), Last Glacial Maximum (LGM, 21 ka) and Last Interglacial (LIG, 120 ka). We generated historical stability maps (refugial areas) by overlapping presence/absence projections of all scenarios, and checked consistencies with qualitative comparisons with available fossil pollen records. We built a spatially explicit simultaneous autoregressive model to explore the relationship between current climate, climatic stability, and squamate species richness.Results  Models predicted the LGM and LIG as the periods of narrowest and widest Cerrado distributions, respectively, and were largely corroborated by palynological evidence. We found evidence for two savanna corridors (eastern coastal during the LIG, and Andean during the LGM) and predicted a large refugial area in the north‐eastern Cerrado (Serra Geral de Goiás refugium). Variables related to climatic stability predicted squamate richness better than present climatic variables did.Main conclusions  Our results indicate that Bolivian savannas should be included within the Cerrado range and that the Cerrado’s biogeographical counterparts are not Chaco and Caatinga but rather the disjunct savannas of the Guyana shield plateaus. Climatic stability is a good predictor of Cerrado squamate richness, and our stability maps could be used in future studies to test diversity patterns and genetic signatures of different taxonomic groups and as a higher‐order landscape biodiversity surrogate for conservation planning.
Parallel and lineage‐specific molecular adaptation to climate in boreal black spruce
Authors: PRUNIER JULIEN , GÉRARDI SÉBASTIEN , LAROCHE JÉRÔME , BEAULIEU JEAN , BOUSQUET JEAN 
Published: July 2012

AbstractIn response to selective pressure, adaptation may follow different genetic pathways throughout the natural range of a species due to historical differentiation in standing genetic variation. Using 41 populations of black spruce (Picea mariana), the objectives of this study were to identify adaptive genetic polymorphisms related to temperature and precipitation variation across the transcontinental range of the species, and to evaluate the potential influence of historical events on their geographic distribution. Population structure was first inferred using 50 control nuclear markers. Then, 47 candidate gene SNPs identified in previous genome scans were tested for relationship with climatic factors using an FST‐based outlier method and regressions between allele frequencies and climatic variations. Two main intraspecific lineages related to glacial vicariance were detected at the transcontinental scale. Within‐lineage analyses of allele frequencies allowed the identification of 23 candidate SNPs significantly related to precipitation and/or temperature variation, among which seven were common to both lineages, eight were specific to the eastern lineage and eight were specific to the western lineage. The implication of these candidate SNPs in adaptive processes was further supported by gene functional annotations. Multiple evidences indicated that the occurrence of lineage‐specific adaptive SNPs was better explained by selection acting on historically differentiated gene pools rather than differential selection due to heterogeneity of interacting environmental factors and pleiotropic effects. Taken together, these findings suggest that standing genetic variation of potentially adaptive nature has been modified by historical events, hence affecting the outcome of recent selection and leading to different adaptive routes between intraspecific lineages.
Laminar distribution of the pathological changes in sporadic frontotemporal lobar degeneration with transactive response (TAR) DNA‐binding protein of 43 kDa (TDP‐43) proteinopathy: a quantitative study using polynomial curve fitting
Authors: Armstrong R. A. , Hamilton R. L. , Mackenzie I. R. A. , Hedreen J. , Cairns N. J. 
Published: July 2012

R. A. Armstrong, R. L. Hamilton, I. R. A. Mackenzie, J. Hedreen and N. J. Cairns (2013) Neuropathology and Applied Neurobiology39, 335–347Laminar distribution of the pathological changes in sporadic frontotemporal lobar degeneration with transactive response (TAR) DNA‐binding protein of 43 kDa (TDP‐43) proteinopathy: a quantitative study using polynomial curve fittingAims: Previous data suggest heterogeneity in laminar distribution of the pathology in the molecular disorder frontotemporal lobar degeneration (FTLD) with transactive response (TAR) DNA‐binding protein of 43 kDa (TDP‐43) proteinopathy (FTLD‐TDP). To study this heterogeneity, we quantified the changes in density across the cortical laminae of neuronal cytoplasmic inclusions, glial inclusions, neuronal intranuclear inclusions, dystrophic neurites, surviving neurones, abnormally enlarged neurones, and vacuoles in regions of the frontal and temporal lobe. Methods: Changes in density of histological features across cortical gyri were studied in 10 sporadic cases of FTLD‐TDP using quantitative methods and polynomial curve fitting. Results: Our data suggest that laminar neuropathology in sporadic FTLD‐TDP is highly variable. Most commonly, neuronal cytoplasmic inclusions, dystrophic neurites and vacuolation were abundant in the upper laminae and glial inclusions, neuronal intranuclear inclusions, abnormally enlarged neurones, and glial cell nuclei in the lower laminae. TDP‐43‐immunoreactive inclusions affected more of the cortical profile in longer duration cases; their distribution varied with disease subtype, but was unrelated to Braak tangle score. Different TDP‐43‐immunoreactive inclusions were not spatially correlated. Conclusions: Laminar distribution of pathological features in 10 sporadic cases of FTLD‐TDP is heterogeneous and may be accounted for, in part, by disease subtype and disease duration. In addition, the feedforward and feedback cortico‐cortical connections may be compromised in FTLD‐TDP.
Host switching between native and non‐native trees in a population of the canker pathogen Chrysoporthe cubensis from Colombia
Authors: van der Merwe N. A. , Steenkamp E. T. , Rodas C. , Wingfield B. D. , Wingfield M. J. 
Published: July 2012

The purpose of this study was to test the hypothesis that Chrysoporthe cubensis on native trees in South America could be the source of the pathogen that causes severe stem cankers and often mortality in commercially propagated Eucalyptus trees. This was done by investigating populations originating from two adjacent Eucalyptus (Myrtaceae) plantations in Colombia, and wild Miconia rubiginosa trees (Melastomataceae) growing alongside these stands. Polymorphic microsatellite markers were used to quantify allele sizes in 20 and 39 isolates from the two Eucalyptus stands and 32 isolates from adjacent M. rubiginosa trees. Gene and genotypic diversities were calculated from these data, and population differentiation and assignment tests were performed to ascertain whether the populations were genetically different. Results showed that there were no differences between any of the populations using these techniques, and that they can be treated as a single population. Therefore, the results support the hypothesis that host switching has occurred in C. cubensis in Colombia.
Modification of anxiety‐like behaviors by nociceptin/orphanin FQ (N/OFQ) and time‐dependent changes in N/OFQ‐NOP gene expression following ethanol withdrawal
Authors: Aujla Harinder , Cannarsa Rosalia , Romualdi Patrizia , Ciccocioppo Roberto , Martin‐Fardon Rémi , Weiss Friedbert 
Published: July 2012

AbstractAnxiety is a key consequence of ethanol withdrawal and important risk factor for relapse. The neuropeptide nociceptin/orphanin FQ (N/OFQ) or agonists at this peptide's receptor (NOP) exert anxiolytic‐like and antistress actions. N/OFQ dysfunction has been linked to both a high‐anxiety behavioral phenotype and excessive ethanol intake. Recent studies suggest a possible link between genetic polymorphisms of the NOP transcript and alcoholism. Thus, in the present study, the effects of intracerebroventricularly administered N/OFQ were tested for modification of anxiety‐like behaviors, using the shock‐probe defensive burying and elevated plus‐maze tests, in ethanol‐dependent versus non‐dependent rats, 1 and 3 weeks following termination of ethanol exposure. Additionally, prepro‐N/OFQ (ppN/OFQ) and NOP receptor gene expression was measured in the central nucleus of the amygdala, in the bed nucleus of the stria terminalis and in the lateral hypothalamus at the same timepoints in separate subjects. One week post‐ethanol, N/OFQ dose‐dependently attenuated elevated anxiety‐like behavior in ethanol‐dependent rats and produced anxiolytic‐like effects in non‐dependent controls in both behavioral tests. However, 3 weeks post‐ethanol, N/OFQ altered behavior consistent with anxiogenic‐like actions in ethanol‐dependent rats but continued to exert anxiolytic‐like actions in non‐dependent controls. These findings were paralleled by ethanol history‐dependent changes of ppN/OFQ and NOP gene expression that showed a distinctive time course in the examined brain structures. The results demonstrate that ethanol dependence and withdrawal are associated with neuroadaptive changes in the N/OFQ‐NOP system, suggesting a role of this neuropeptidergic pathway as a therapeutic target for the treatment of alcohol abuse.
Neuroplasticity, axonal guidance and micro‐RNA genes are associated with morphine self‐administration behavior
Authors: Tapocik Jenica D. , Luu Truong V. , Mayo Cheryl L. , Wang Bi‐Dar , Doyle Erin , Lee Alec D. , Lee Norman H. , Elmer Greg I. 
Published: July 2012

AbstractNeuroadaptations in the ventral striatum (VS) and ventral midbrain (VMB) following chronic opioid administration are thought to contribute to the pathogenesis and persistence of opiate addiction. In order to identify candidate genes involved in these neuroadaptations, we utilized a behavior‐genetics strategy designed to associate contingent intravenous drug self‐administration with specific patterns of gene expression in inbred mice differentially predisposed to the rewarding effects of morphine. In a Yoked‐control paradigm, C57BL/6J mice showed clear morphine‐reinforced behavior, whereas DBA/2J mice did not. Moreover, the Yoked‐control paradigm revealed the powerful consequences of self‐administration versus passive administration at the level of gene expression. Morphine self‐administration in the C57BL/6J mice uniquely up‐ or down‐regulated 237 genes in the VS and 131 genes in the VMB. Interestingly, only a handful of the C57BL/6J self‐administration genes (<3%) exhibited a similar expression pattern in the DBA/2J mice. Hence, specific sets of genes could be confidently assigned to regional effects of morphine in a contingent‐ and genotype‐dependent manner. Bioinformatics analysis revealed that neuroplasticity, axonal guidance and micro‐RNAs (miRNAs) were among the key themes associated with drug self‐administration. Noteworthy were the primary miRNA genes H19 and micro‐RNA containing gene (Mirg), processed, respectively, to mature miRNAs miR‐675 and miR‐154, because they are prime candidates to mediate network‐like changes in responses to chronic drug administration. These miRNAs have postulated roles in dopaminergic neuron differentiation and mu‐opioid receptor regulation. The strategic approach designed to focus on reinforcement‐associated genes provides new insight into the role of neuroplasticity pathways and miRNAs in drug addiction.
Application of microsatellite markers to evaluate the heterozygosity from the popcorn composite CMS‐43 (Zea maysL.) during eight cycles of selection
Authors: Franzoni Juliana , Scapim Carlos A. , Beviláqua Maycon R. R. , De Fátima Pires da Silva Machado Maria , Pacheco Cleso A. P. , Mangolin Claudete A. 
Published: July 2012

With 5 tablesAbstractMaize breeders in Brazil developed the popcorn cultivar BRS Angela after eight cycles of recurrent selection using the composite CMS‐43. We extracted the genomic DNA from the leaves of the BRS Angela, and we used 20 microsatellite markers to assess both the genetic distance and variability of this variety along the eight cycles (C0, CI, CII, CIII, CIV, CV, CVIAand CVIB) of the composite CMS‐43. Sixty‐nine alleles were detected in the popcorn cultivar BRS Angela with an average of 3.45 alleles per polymorphic locus. There was significant effect (P ≤ 0.01) only for D allele at theUmc 2343locus and for the alleles A and B at theUmc 2226locus. There was no tendency in the changes in the allele frequencies, presumably, because of selection for grain yield and popping expansion. The observed heterozygosity along these cycles ranged from 38.67% (CIII) to 26.67% (CVIB). These values indicate the presence of heterozygosity in the breeding cycles, and therefore, the ‘BRS Angela’ can participate in new cycles of recurrent selection.
Microstructure‐texture‐fracture toughness property correlation in annealed Al‐6Mg alloy with minor scandium and zirconium additions
Authors: SEN R. , GHOSH M. , KAISER M. S. 
Published: July 2012

ABSTRACTThe effect of minor addition of scandium and zirconium on the fracture toughness (FT) behaviour of aluminium‐6 wt% magnesium alloy is studied. Texture measurement and transmission electron microscopy have revealed that the evolution of texture in cast alloys after annealing is decided by the morphology and character of the precipitates. It is further demonstrated that the said minor addition influences the FT behaviour of Al‐6Mg alloy by manipulating in‐plane anisotropy as decided by the precipitate morphology. Textural situation in annealed state has also been related to the FT behaviour.
Estradiol acts during a post‐pubertal sensitive period to shorten free‐running circadian period in male Octodon degus
Authors: Hummer Daniel L. , Peckham Elizabeth M. , Lee Theresa M. 
Published: July 2012

AbstractThe free‐running circadian period is approximately 30 min shorter in adult male than in adult female Octodon degus. The sex difference emerges after puberty, resulting from a shortened free‐running circadian period in males. Castration before puberty prevents the emergence of the sex difference, but it is not a function of circulating gonadal hormones as such, because castration later in life does not affect free‐running circadian period. The aim of this study was to determine whether or not the shortening of the free‐running circadian period in male degus results from exposure to gonadal hormones after puberty. We hypothesized that masculinization of the circadian period results from an organizational effect of androgen exposure during a post‐pubertal sensitive period. Male degus were castrated before puberty and implanted with capsules filled with dihydrotestosterone (DHT), 17β‐estradiol (E2) or empty capsules at one of three ages: peri‐puberty (2–7 months), post‐puberty (7–12 months), or adulthood (14–19 months). Long‐term exposure to DHT or E2 did not result in a shortened free‐running circadian period when administered at 2–7 or 14–19 months of age. However, E2 treatment from 7 to 12 months of age decreased the free‐running circadian period in castrated males. This result was replicated in a subsequent experiment in which E2 treatment was limited to 8–12 months of age. E2 treatment at 7–12 months of age had no effect on the free‐running circadian period in ovariectomized females. Thus, there appears to be a post‐pubertal sensitive period for sexual differentiation of the circadian system of degus, during which E2 exposure decreases the free‐running circadian period in males. These data demonstrate that gonadal hormones can act during adolescent development to permanently alter the circadian system.
Virtual Worlds and Their Challenge to Philosophy: Understanding the “Intravirtual” and the “Extravirtual”
Authors: Søraker Johnny Hartz 
Published: July 2012

AbstractThe Web, in particular real‐time interactions in three‐dimensional virtual environments (virtual worlds), comes with a set of unique characteristics that leave our traditional frameworks inapplicable. The present article illustrates this by arguing that the notion of “technology relations,” as put forward by Ihde and Verbeek, becomes inapplicable when it comes to the Internet, and this inapplicability shows why these phenomena require new philosophical frameworks. Against this background, and more constructively, the article proposes a fundamental distinction between “intravirtual” and “extravirtual” consequences—a distinction that allows us to understand and conceptualize real‐time interactions online more accurately. By relating this distinction to Searle's notion of “condition of satisfaction,” the article also shows its implications for judging real‐time, online interactions in virtual worlds as irrational and/or immoral. The ultimate purpose is to illustrate how new philosophical concepts and frameworks can allow us to better account for the unique characteristics of the Internet.
TheWeb‐Extended Mind
Authors: Smart Paul R. 
Published: July 2012

AbstractThis article explores the notion of theWeb‐extended mind, which is the idea that the technological and informational elements of theWeb can sometimes serve as part of the mechanistic substrate that realizes human mental states and processes. It is argued that while current forms of theWeb may not be particularly suited to the realization ofWeb‐extended minds, new forms of user interaction technology as well as new approaches to information representation do provide promising new opportunities forWeb‐based forms of cognitive extension. In addition, it is suggested that extended cognitive systems often rely on the emergence of social practices and conventions that shape how a technology is used.Web‐extended minds may thus depend on forms of socio‐technical co‐evolution in which social forces and factors play just as important a role as do the processes of technology design and development.
Web Ontologies as Renewal of Classical Philosophical Ontology
Authors: Livet Pierre 
Published: July 2012

AbstractDo Web devices (addresses, tags, networks, and the rest) have counterparts in classical ontology? Yes, but they allow us also to introduce more refined distinctions. In addition, their dynamic use could inspire a dynamic reconception of classical ontology. In the process of making explicit ontological types, different types can be undistinguished at the first step (considered as “floating types”) to be defined only in a further step, one in which their function as distinguishers of other kinds of entities has to be made explicit. The fact that the ontological import of some node in a network of tags and addresses could evolve with the transformation of the network can most easily find an interpretation in this dynamic conception of ontology.
Evaluating Google as an Epistemic Tool
Authors: Simpson Thomas W. 
Published: July 2012

AbstractThis article develops a social epistemological analysis of Web‐based search engines, addressing the following questions. First, what epistemic functions do search engines perform? Second, what dimensions of assessment are appropriate for the epistemic evaluation of search engines? Third, how well do current search engines perform on these? The article explains why they fulfil the role of a surrogate expert, and proposes three ways of assessing their utility as an epistemic tool—timeliness, authority prioritisation, and objectivity. “Personalisation” is a current trend in Internet‐delivered services, and consists in tailoring online content to the interests of the individual user. It is argued here that personalisation threatens the objectivity of search results. Objectivity is a public good; so there is a prima facie case for government regulation of search engines.
Being, Space, and Time on the Web
Authors: Vafopoulos Michalis 
Published: July 2012

AbstractTheWeb initially emerged as an “antidote” to accumulated scientific knowledge, since it enables global representation and communication at a minimum cost. Its gigantic scale and interdependence allow us our ability to find relevant information and develop trustworthy contexts. It is time for science to compensate by providing an epistemological “antidote” to Web issues. Philosophy should be in the front line by forming the salient questions and analysis. We need a theory about Web being that will bridge philosophical thinking and engineering. This article analyzes existence and spatiotemporality in the Web and how it transforms the traditional actualities. The resulting issues concern the self‐determination of a being and the way in which the Web could be a free and open platform for innovation and participation.