2,522 research outputs found

    Distinct timescales of population coding across cortex

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    The cortex represents information across widely varying timescales1–5. For instance, sensory cortex encodes stimuli that fluctuate over few tens of milliseconds6,7, whereas in association cortex behavioral choices can require the maintenance of information over seconds8,9. However, it remains poorly understood if diverse timescales result mostly from features intrinsic to individual neurons or from neuronal population activity. This question is unanswered because the timescales of coding in populations of neurons have not been studied extensively, and population codes have not been compared systematically across cortical regions. Here we discovered that population codes can be essential to achieve long coding timescales. Furthermore, we found that the properties of population codes differ between sensory and association cortices. We compared coding for sensory stimuli and behavioral choices in auditory cortex (AC) and posterior parietal cortex (PPC) as mice performed a sound localization task. Auditory stimulus information was stronger in AC than in PPC, and both regions contained choice information. Although AC and PPC coded information by tiling in time neurons that were transiently informative for ~200 milliseconds, the areas had major differences in functional coupling between neurons, measured as activity correlations that could not be explained by task events. Coupling among PPC neurons was strong and extended over long time lags, whereas coupling among AC neurons was weak and short-lived. Stronger coupling in PPC led to a population code with long timescales and a representation of choice that remained consistent for approximately one second. In contrast, AC had a code with rapid fluctuations in stimulus and choice information over hundreds of milliseconds. Our results reveal that population codes differ across cortex and that coupling is a variable property of cortical populations that affects the timescale of information coding and the accuracy of behavior

    Clinical Performance of an Automated Reader in Interpreting Malaria Rapid Diagnostic Tests in Tanzania.

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    Parasitological confirmation of malaria is now recommended in all febrile patients by the World Health Organization (WHO) to reduce inappropriate use of anti-malarial drugs. Widespread implementation of rapid diagnostic tests (RDTs) is regarded as an effective strategy to achieve this goal. However, the quality of diagnosis provided by RDTs in remote rural dispensaries and health centres is not ideal. Feasible RDT quality control programmes in these settings are challenging. Collection of information regarding diagnostic events is also very deficient in low-resource countries. A prospective cohort of consecutive patients aged more than one year from both genders, seeking routine care for febrile episodes at dispensaries located in the Bagamoyo district of Tanzania, were enrolled into the study after signing an informed consent form. Blood samples were taken for thick blood smear (TBS) microscopic examination and malaria RDT (SD Bioline Malaria Antigen Pf/PanTM (SD RDT)). RDT results were interpreted by both visual interpretation and DekiReaderTM device. Results of visual interpretation were used for case management purposes. Microscopy was considered the "gold standard test" to assess the sensitivity and specificity of the DekiReader interpretation and to compare it to visual interpretation. In total, 1,346 febrile subjects were included in the final analysis. The SD RDT, when used in conjunction with the DekiReader and upon visual interpretation, had sensitivities of 95.3% (95% CI, 90.6-97.7) and 94.7% (95% CI, 89.8--97.3) respectively, and specificities of 94.6% (95% CI, 93.5--96.1) and 95.6% (95% CI, 94.2--96.6), respectively to gold standard. There was a high percentage of overall agreement between the two methods of interpretation. The sensitivity and specificity of the DekiReader in interpretation of SD RDTs were comparable to previous reports and showed high agreement to visual interpretation (>98%). The results of the study reflect the situation in real practice and show good performance characteristics of DekiReader on interpreting malaria RDTs in the hands of local laboratory technicians. They also suggest that a system like this could provide great benefits to the health care system. Further studies to look at ease of use by community health workers, and cost benefit of the system are warranted

    Canine pseudopregnancy: an evaluation of prevalence and current treatment protocols in the UK

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    Background: There is a dearth of literature on pseudopregnancy in the bitch, with only a few treatment-based studies published since the 1990s. Pseudopregnancy may be under-recognised in bitches and may account for a proportion of behavioural cases seen in veterinary practices including aggression. Little is known about commonly used treatments for overtly pseudopregnant bitches and it is possible that current regimes may not be prescribed for a sufficient duration to control any clinical signs including, physical and behavioural changes. To investigate current trends in diagnosis and treatment of canine pseudopregnancy, a postal survey was sent to 2000 randomly selected veterinary surgeons in UK veterinary practices. The questionnaire queried how often vets recognise cases of pseudopregnancy in spayed and entire bitches, which physical or behavioural signs are commonly recognised for diagnosis, and which management or treatment protocols are used. Results: The response rate was 19.8% (397/2000). Ninety-six percent of veterinary surgeons reported seeing pseudopregnant bitches showing behavioural changes without any physical changes within the last 12 months. Of those behavioural changes, collecting and mothering objects was the most frequently reported behavioural sign (96%). Ninety-seven percent of vets had seen aggression in pseudopregnant bitches. Nevertheless, only 52% of vets routinely asked owners about behavioural changes during consultations. Forty-nine percent of respondents reported seeing pseudopregnancy in spayed bitches. The most commonly reported physical sign was enlarged mammary glands and/or milk production (89%). Treatment options varied (surgical, medical or none) and depended on duration and severity of physical and behavioural signs, owners’ preference, cost, concurrent disease, drug availability and previous history. Conclusions: This is the largest epidemiological study of canine pseudopregnancy in the UK. The prevalence and severity of clinical signs in dogs with pseudopregnancy are variable and possibly under-estimated. Dogs with overt pseudopregnancy experience diverse physical and behavioural changes and information on standard treatment protocols are lacking. Although, progress on our understanding of diagnosis and treatment of pseudopregnancy in spayed and entire bitches has been made, further studies are warranted

    Everyday cosmopolitanism in representations of Europe among young Romanians in Britain

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    The paper presents an analysis of everyday cosmopolitanism in constructions of Europe among young Romanian nationals living in Britain. Adopting a social representations approach, cosmopolitanism is understood as a cultural symbolic resource that is part of everyday knowledge. Through a discursively-oriented analysis of focus group data, we explore the ways in which notions of cosmopolitanism intersect with images of Europeanness in the accounts of participants. We show that, for our participants, representations of Europe are anchored in an Orientalist schema of West-vs.-East, whereby the West is seen as epitomising European values of modernity and progress, while the East is seen as backward and traditional. Our findings further show that representations of cosmopolitanism reinforce this East/West dichotomy, within a discourse of ‘Occidental cosmopolitanism’. The paper concludes with a critical discussion of the diverse and complex ideological foundations of these constructions of European cosmopolitanism and their implications

    Attributing scientific and technical progress: the case of holography

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    Holography, the three-dimensional imaging technology, was portrayed widely as a paradigm of progress during its decade of explosive expansion 1964–73, and during its subsequent consolidation for commercial and artistic uses up to the mid 1980s. An unusually seductive and prolific subject, holography successively spawned scientific insights, putative applications and new constituencies of practitioners and consumers. Waves of forecasts, associated with different sponsors and user communities, cast holography as a field on the verge of success—but with the dimensions of success repeatedly refashioned. This retargeting of the subject represented a degree of cynical marketeering, but was underpinned by implicit confidence in philosophical positivism and faith in technological progressivism. Each of its communities defined success in terms of expansion, and anticipated continual progressive increase. This paper discusses the contrasting definitions of progress in holography, and how they were fashioned in changing contexts. Focusing equally on reputed ‘failures’ of some aspects of the subject, it explores the varied attributes by which success and failure were linked with progress by different technical communities. This important case illuminates the peculiar post-World War II environment that melded the military, commercial and popular engagement with scientific and technological subjects, and the competing criteria by which they assessed the products of science

    The Atacama Cosmology Telescope: Cosmological parameters from three seasons of data

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    We present constraints on cosmological and astrophysical parameters from high-resolution microwave background maps at 148 GHz and 218 GHz made by the Atacama Cosmology Telescope (ACT) in three seasons of observations from 2008 to 2010. A model of primary cosmological and secondary foreground parameters is fit to the map power spectra and lensing deflection power spectrum, including contributions from both the thermal Sunyaev-Zeldovich (tSZ) effect and the kinematic Sunyaev-Zeldovich (kSZ) effect, Poisson and correlated anisotropy from unresolved infrared sources, radio sources, and the correlation between the tSZ effect and infrared sources. The power ell^2 C_ell/2pi of the thermal SZ power spectrum at 148 GHz is measured to be 3.4 +\- 1.4 muK^2 at ell=3000, while the corresponding amplitude of the kinematic SZ power spectrum has a 95% confidence level upper limit of 8.6 muK^2. Combining ACT power spectra with the WMAP 7-year temperature and polarization power spectra, we find excellent consistency with the LCDM model. We constrain the number of effective relativistic degrees of freedom in the early universe to be Neff=2.79 +\- 0.56, in agreement with the canonical value of Neff=3.046 for three massless neutrinos. We constrain the sum of the neutrino masses to be Sigma m_nu < 0.39 eV at 95% confidence when combining ACT and WMAP 7-year data with BAO and Hubble constant measurements. We constrain the amount of primordial helium to be Yp = 0.225 +\- 0.034, and measure no variation in the fine structure constant alpha since recombination, with alpha/alpha0 = 1.004 +/- 0.005. We also find no evidence for any running of the scalar spectral index, dns/dlnk = -0.004 +\- 0.012.Comment: 26 pages, 22 figures. This paper is a companion to Das et al. (2013) and Dunkley et al. (2013). Matches published JCAP versio

    The pirate in the pump: children's views of objects as imaginary friends at the start of school

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    The main aim of this paper is to use a phenomenological approach (Merleau-Ponty, 1962. Phenomenology of Perception. Evanston: Northwestern University Press; Merleau-Ponty. 1968. The Visible and the Invisible: Followed by Working Notes. Evanston: Northern University Press) to contribute a new theoretical understanding of what imaginary friends mean for children in the context of starting school. The paper addresses the specific area of ‘object-friends’ and draws on examples from an empirical and consultative study of a small sample of five and six-year-old children’s everyday experiences of friendship in school. The paper argues that if practitioners consider embodiment approaches and listen attentively to the knowledge and information that children share about their imaginary friends, this could be used to nurture children’s early learnin

    L-lysine as adjunctive treatment in patients with schizophrenia: a single-blinded, randomized, cross-over pilot study

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    <p>Abstract</p> <p>Background</p> <p>Accumulating evidence suggests that the brain's nitric oxide (NO) signalling system may be involved in the pathophysiology of schizophrenia and could thus constitute a novel treatment target. The study was designed to investigate the benefit of L-lysine, an amino acid that interferes with NO production, as an add-on treatment for schizophrenia.</p> <p>Methods</p> <p>L-lysine, 6 g/day, was administered to 10 patients with schizophrenia as an adjunctive to their conventional antipsychotic medication. The study was designed as a single-blinded, cross-over study where patients were randomly assigned to initial treatment with either L-lysine or placebo and screened at baseline, after four weeks when treatment was crossed over, and after eight weeks.</p> <p>Results</p> <p>L-lysine treatment caused a significant increase in blood concentration of L-lysine and was well tolerated. A significant decrease in positive symptom severity, measured by the Positive And Negative Syndrome Scale (PANSS), was detected. A certain decrease in score was also observed during placebo treatment and the effects on PANSS could not unequivocally be assigned to the L-lysine treatment. Furthermore, performance on the Wisconsin Card Sorting Test was significantly improved compared to baseline, an effect probably biased by training. Subjective reports from three of the patients indicated decreased symptom severity and enhanced cognitive functioning.</p> <p>Conclusions</p> <p>Four-week L-lysine treatment of 6 g/day caused a significant increase in blood concentration of L-lysine that was well tolerated. Patients showed a significant decrease in positive symptoms as assessed by PANSS in addition to self-reported symptom improvement by three patients. The NO-signalling pathway is an interesting, potentially new treatment target for schizophrenia; however, the effects of L-lysine need further evaluation to decide the amino acid's potentially beneficial effects on symptom severity in schizophrenia.</p> <p>Trial registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT00996242">NCT00996242</a></p

    Genomic approaches to understanding population divergence and speciation in birds

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    © 2016 American Ornithologists\u27 Union. The widespread application of high-throughput sequencing in studying evolutionary processes and patterns of diversification has led to many important discoveries. However, the barriers to utilizing these technologies and interpreting the resulting data can be daunting for first-time users. We provide an overview and a brief primer of relevant methods (e.g., whole-genome sequencing, reduced-representation sequencing, sequence-capture methods, and RNA sequencing), as well as important steps in the analysis pipelines (e.g., loci clustering, variant calling, whole-genome and transcriptome assembly). We also review a number of applications in which researchers have used these technologies to address questions related to avian systems. We highlight how genomic tools are advancing research by discussing their contributions to 3 important facets of avian evolutionary history. We focus on (1) general inferences about biogeography and biogeographic history, (2) patterns of gene flow and isolation upon secondary contact and hybridization, and (3) quantifying levels of genomic divergence between closely related taxa. We find that in many cases, high-throughput sequencing data confirms previous work from traditional molecular markers, although there are examples in which genome-wide genetic markers provide a different biological interpretation. We also discuss how these new data allow researchers to address entirely novel questions, and conclude by outlining a number of intellectual and methodological challenges as the genomics era moves forward
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