974 research outputs found
Prioritization of fish communities with a view to conservation and restoration on a large scale European basin, the Loire (France)
The hierarchical organization of important sites for the conservation or the
restoration of fish communities is a great challenge for managers, especially because of
financial or time constraints. In this perspective, we developed a methodology, which is
easy to implement in different locations. Based on the fish assemblage characteristics of
the Loire basin (France), we created a synthetic conservation value index including the
rarity, the conservation status and the species origin. The relationship between this new
synthetic index and the Fish-Based Index allowed us to establish a classification protocol
of the sites along the Loire including fish assemblages to be restored or conserved. Sites
presenting disturbed fish assemblages, a low rarity index, few threatened species, and a
high proportion of non-native species were considered as important for the restoration of
fish biodiversity. These sites were found mainly in areas where the assemblages are
typical of the bream zone, e.g. with a higher number of eurytopic and limnophilic
species. On the contrary, important sites for conservation were defined as having an
important conservation potential (high RI, a lot of threatened species, and few nonnatives
fish species) and an undisturbed fish assemblage similar to the expected community
if habitats are undisturbed. Important sites for conservation were found in the
Loire basin’s medium reaches which host assemblages typical for the grayling and the
barbell zones, e.g. with a higher number of rheophilic species. The synthetic conservation value index could be adapted and completed with other criteria according to
management priorities and capacities
A single-photon transistor using nano-scale surface plasmons
It is well known that light quanta (photons) can interact with each other in
nonlinear media, much like massive particles do, but in practice these
interactions are usually very weak. Here we describe a novel approach to
realize strong nonlinear interactions at the single-photon level. Our method
makes use of recently demonstrated efficient coupling between individual
optical emitters and tightly confined, propagating surface plasmon excitations
on conducting nanowires. We show that this system can act as a nonlinear
two-photon switch for incident photons propagating along the nanowire, which
can be coherently controlled using quantum optical techniques. As a novel
application, we discuss how the interaction can be tailored to create a
single-photon transistor, where the presence or absence of a single incident
photon in a ``gate'' field is sufficient to completely control the propagation
of subsequent ``signal'' photons.Comment: 20 pages, 4 figure
Capturing egocentric biases in reference reuse during collaborative dialogue
Words that are produced aloud—and especially self-produced ones—are remembered better than words that are not, a phenomenon labeled the production effect in the field of memory research. Two experiments were conducted to determine whether this effect can be generalized to dialogue, and how it might affect dialogue management. Triads (Exp. 1) or dyads (Exp. 2) of participants interacted to perform a collaborative task. Analyzing reference reuse during the interaction revealed that the participants were more likely to reuse the references that they had presented themselves, on the one hand, and those that had been accepted through verbatim repetition, on the other. Analyzing reference recall suggested that the greater accessibility of self-presented references was only transient. Moreover, among partner-presented references, those discussed while the participant had actively taken part in the conversation were more likely to be recalled than those discussed while the participant had been inactive. These results contribute to a better understanding of how individual memory processes might contribute to collaborative dialogue
A functional polymorphism under positive evolutionary selection in ADRB2 is associated with human intelligence with opposite effects in the young and the elderly
Comparative genomics offers a novel approach to unravel the genetic basis of complex traits. We performed a two stage analysis where genes ascertained for enhanced protein evolution in primates are subsequently searched for the presence of non-synonymous coding SNPs in the current human population at amino acid sites that differ between humans and chimpanzee. Positively selected genes among primates are generally presumed to determine phenotypic differences between humans and chimpanzee, such as the enhanced cognitive ability of our species. Amino acid substitutions segregating in humans at positively selected amino acid sites are expected to affect phenotypic differences among humans. Therefore we conducted an association study in two family based cohorts and one population based cohort between cognitive ability and the most likely candidate gene among the five that harbored more than one such polymorphism. The derived, human-specific allele of the beta-2 adrenergic receptor Arg16Gly polymorphism was found to be the increaser allele for performance IQ in the young, family based cohort but the decreaser allele for two different measures of cognition in the large Scottish cohort of unrelated individuals. The polymorphism is known to affect signaling activity and modulation of beta-2 adrenergic signaling has been shown to adjust memory consolidation, a trait related to cognition. The opposite effect of the polymorphism on cognition in the two age classes observed in the different cohorts resembles the effect of ADRB2 on hypertension, which also has been reported to be age dependent. This result illustrates the relevance of comparative genomics to detect genes that are involved in human behavior. © 2008 Springer Science+Business Media, LLC
Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.
Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition
Nurse moral disengagement
Background: Ethics is a founding component of the nursing profession; however, nurses sometimes find it difficult to constantly adhere to the required ethical standards. There is limited knowledge about the factors that cause a committed nurse to violate standards; moral disengagement, originally developed by Bandura, is an essential variable to consider. Research objectives: This study aimed at developing and validating a nursing moral disengagement scale and investigated how moral disengagement is associated with counterproductive and citizenship behaviour at work. Research design: The research comprised a qualitative study and a quantitative study, combining a crossvalidation approach and a structural equation model. Participants and research context: A total of 60 Italian nurses (63% female) involved in clinical work and enrolled as students in a postgraduate master’s programme took part in the qualitative study. In 2012, the researchers recruited 434 nurses (76% female) from different Italian hospitals using a convenience sampling method to take part in the quantitative study. Ethical considerations: All the organisations involved and the university gave ethical approval; all respondents participated on a voluntary basis and did not receive any form of compensation. Findings: The nursing moral disengagement scale comprised a total of 22 items. Results attested the mono-dimensionality of the scale and its good psychometric properties. In addition, results highlighted a significant association between moral disengagement and both counterproductive and citizenship behaviours
Use of wild bird surveillance, human case data and GIS spatial analysis for predicting spatial distributions of West Nile Virus in Greece
West Nile Virus (WNV) is the causative agent of a vector-borne, zoonotic disease with a worldwide distribution. Recent expansion and introduction of WNV into new areas, including southern Europe, has been associated with severe disease in humans and equids, and has increased concerns regarding the need to prevent and control future WNV outbreaks. Since 2010, 524 confirmed human cases of the disease have been reported in Greece with greater than 10% mortality. Infected mosquitoes, wild birds, equids, and chickens have been detected and associated with human disease. The aim of our study was to establish a monitoring system with wild birds and reported human cases data using Geographical Information System (GIS). Potential distribution of WNV was modelled by combining wild bird serological surveillance data with environmental factors (e.g. elevation, slope, land use, vegetation density, temperature, precipitation indices, and population density). Local factors including areas of low altitude and proximity to water were important predictors of appearance of both human and wild bird cases (Odds Ratio = 1,001 95%CI = 0,723–1,386). Using GIS analysis, the identified risk factors were applied across Greece identifying the northern part of Greece (Macedonia, Thrace) western Greece and a number of Greek islands as being at highest risk of future outbreaks. The results of the analysis were evaluated and confirmed using the 161 reported human cases of the 2012 outbreak predicting correctly (Odds = 130/31 = 4,194 95%CI = 2,841–6,189) and more areas were identified for potential dispersion in the following years. Our approach verified that WNV risk can be modelled in a fast cost-effective way indicating high risk areas where prevention measures should be implemented in order to reduce the disease incidence
Catechol O-methyl transferase and dopamine D2 receptor gene polymorphisms: evidence of positive heterosis and gene–gene interaction on working memory functioning.
The COMT Va
Disrupting astrocyte-neuron lactate transfer persistently reduces conditioned responses to cocaine.
A central problem in the treatment of drug addiction is the high risk of relapse often precipitated by drug-associated cues. The transfer of glycogen-derived lactate from astrocytes to neurons is required for long-term memory. Whereas blockade of drug memory reconsolidation represents a potential therapeutic strategy, the role of astrocyte-neuron lactate transport in long-term conditioning has received little attention. By infusing an inhibitor of glycogen phosphorylase into the basolateral amygdala of rats, we report that disruption of astrocyte-derived lactate not only transiently impaired the acquisition of a cocaine-induced conditioned place preference but also persistently disrupted an established conditioning. The drug memory was rescued by L-Lactate co-administration through a mechanism requiring the synaptic plasticity-related transcription factor Zif268 and extracellular signal-regulated kinase (ERK) signalling pathway but not the brain-derived neurotrophic factor (Bdnf). The long-term amnesia induced by glycogenolysis inhibition and the concomitant decreased expression of phospho-ERK were both restored with L-Lactate co-administration. These findings reveal a critical role for astrocyte-derived lactate in positive memory formation and highlight a novel amygdala-dependent reconsolidation process, whose disruption may offer a novel therapeutic target to reduce the long-lasting conditioned responses to cocaine
Transformation, adaptation and development: relating concepts to practice
In recent years there has been a growing number of academic reviews discussing the theme of transformation and its association with adaptation to climate change. On the one hand this has stimulated exchange of ideas and perspectives on the parameters of transformation, but it has also given rise to confusion in terms of identifying what constitutes a non-incremental form of adaptation on the ground. What this article aims to do instead is help researchers and practitioners relate different interpretations of transformation to practice by proposing a typological framework for categorising forms of change that focuses on mechanisms and objectives. It then discusses how these categorisations link to the broader conceptions and critiques noted above, with the idea that this will enable those who seek to analyse or plan adaptation to better analyse what types of action are potentially constitutive of transformation. In doing so, it should equally assist in the identification and specification of critical questions that need to be asked of such activity in relation to issues of sustainability and equity. As the term transformation gains ground in discussions of climate change adaptation, it is necessary to take a step back, review quite what commentators mean when they use the word, and consider the implications on people, especially the most vulnerable and marginalised, of “doing” or promoting transformation in its different forms
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