816 research outputs found

    Processing and acquisition of coreference: an investigation on binding principles development in brazilian portuguese

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    This article discusses the processing and acquisition of coreference by monolingual children acquiring Brazilian Portuguese (henceforth BP). More specifically, it is about the development of the coreferential relations established in the scope of the sentence, which are ruled by the principles defined by the Binding Theory. By using a version of the cross-modal picture decision task, we investigated how children acquiring BP process the input, in order to identify the coreferential relations present in the sentences and what role the binding principles play in this process. The results showed that binding principles pose different processing costs, and they also revealed a main effect of age, with adults being faster than children. No main effect of matching was found, but an interaction effect between principle and matching was found. To sum up, the results of this study showed that, as expected, both children, as well as adults, know the binding principles, however, processing them effectively increases with age. The binding principles also pose different processing demands, as reflected in the reaction times shown in our results84718

    early life weight patterns and risk of obesity at 5 years a population based cohort study

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    Abstract Childhood obesity is a major public health problem in industrialised countries. Recent studies suggest that obesity in adolescence is associated with characteristics present in early childhood. The aim of this study was to estimate the risk of overweight/obesity at age 5 yr based on BMI percentiles at age 3 and changes in percentiles from birth to 3 years of age. In this population-based study BMI data of 5173 children were collected at ages 3 and 5 yr and were linked to information relative to birth weight. The prevalence of obesity at 5 yr was 4.5%. The risk of obesity for children born large for gestational age was 8.4% while it was 13.8% for children overweight at 3 years and 49.8% for children who were obese at 3 yr, regardless of their previous weight trajectory (the prevalences were 50%, 50% and 53% for stable, moderate and strong increasing trajectory, respectively). BMI percentile at 3 years proved to be an efficient biomarker for sustained obesity at age 5 yr. In practice, if one targeted early preventive interventions to only 15% of the population (3-year-olds affected by overweight/obesity) one can address 80% of children who would be affected by obesity at age 5 yr

    Litter quality changes during decomposition investigated by thermal analysis

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    The litter decomposition process depends on the litter chemical composition, especially the ratio between more labile compounds, cellulose, and the recalcitrant lignin and waxes. Their determination is crucial to predict the process, though lignin measurement presents some limitations due to drawbacks of the different methods. Thermal analysis has been successfully applied to several organic materials in order to obtain quali-quantitative information of the chemical structure of the sample. In this work TG-DTA was used in a short-term litter decomposition study of two broadleaf forest stands of contrasting ages, and the results were compared to those obtained with a chemical method (Klason’s method) commonly used to quantify cellulose and lignin. TG-DTA was applied to the litter and to the cell walls (CW) extracted from the litter, whose cellulose and lignin content was determined using the Klason’s method. When applied to litter, thermal analysis showed a weak correlation with the Klason’s method, though it allowed the detection of the dynamics of waxes, that increased during the decomposition and could influence the later stages of the process. Contrastingly, a good correlation between cellulose and lignin determined with the two methods was found when TG-DTA was applied to the CW. In this case TG-DTA, according to NMR data, also highlighted the changes in the CW chemical structure compared with that of the litters, in particular the loss of waxes and the decreased thermostability of aromatic components. Moreover, a new concept of quality of the decomposing litter, based on the balance between the energy stored in the litter and the energy needed to release it obtained by thermal analysis, was recently introduced. Samples of the old forest litter had an initial energetic balance more favorable than those collected in the young stand. At the end of the period, the decrease in litter quality was greater in the young than in the old forest samples, due to the combined effect of the higher degradation of thermolabile substances and the accumulation of more thermostable components. Thermal analysis seems to have a good potential in litter decomposition studies, as it can link structural and energetic changes during the process

    Is measurement error altered by participation in a physical activity intervention?

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    WINKLER, E., L. WATERS, E. EAKIN, B. FJELDSOE, N. OWEN, and M. REEVES. Is Measurement Error Altered by Participation in a Physical Activity Intervention? Med. Sci. Sports Exerc., Vol. 45, No. 5, pp. 1004-1011, 2013. Purpose: There is no "gold standard" measure for moderate to vigorous physical activity (MVPA); some error is inherent to self-report and device-based measures. Few studies have examined agreement between self-report and device-based measures in the intervention trial context or whether the difference between measures is influenced by intervention participation. Methods: MVPA was measured at baseline and after 6 months by Active Australia Survey (AAS) and by the GT1M accelerometer (>= 1952 counts per minute) in the intervention (n = 135) and usual care control (n = 141) participants of a randomized trial targeting weight loss by MVPA increases and energy intake reductions in adults with type 2 diabetes. Agreement (for each group at each assessment) was examined using the Bland-Altman approach and regression-based modeling. Because the differences between MVPA measures varied with average values ([AAS + GT1M]/2), they were examined as a percentage of average physical activity. t-tests were used to assess unadjusted group differences and changes over time. ANCOVA models tested intervention effects on measurement error at follow-up, adjusted for baseline. Results: Agreement worsened, and variability in the difference measures became greater, as the average amount of MVPA increased. Measurement error differed significantly between groups at follow-up (P = 0.010) but not at baseline (P = 0.157) and changed significantly within the intervention group (P = 0.001) but not the control group (P = 0.164). There was a statistically significant effect of the intervention on measurement error (P = 0.026). Conclusions: Measurement error of self-report relative to the accelerometer appeared to be affected by intervention. Because measurement error cannot be definitively attributed to self-report or accelerometer, it would be prudent to measure both in future studies

    Identification of effective subdominant anti-HIV-1 CD8+ T cells within entire post-infection and post-vaccination immune responses

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    Ajuts: R01/R56 NIH Grant AI-52779 (GDT), NIH F31 Fellowship (1F31AI106519-01)(TLP), Center for AIDS Research (P30 AI 64518) i Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, grant number UM1-AI100645-01 (AM)Abstract.Defining the components of an HIV immunogen that could induce effective CD8+ T cell responses is critical to vaccine development. We addressed this question by investigating the viral targets of CD8+ T cells that potently inhibit HIV replication in vitro, as this is highly predictive of virus control in vivo. We observed broad and potent ex vivo CD8+ T cell-mediated viral inhibitory activity against a panel of HIV isolates among viremic controllers (VC, viral loads <5000 copies/ml), in contrast to unselected HIV-infected HIV Vaccine trials Network (HVTN) participants. Viral inhibition of clade-matched HIV isolates was strongly correlated with the frequency of CD8+ T cells targeting vulnerable regions within Gag, Pol, Nef and Vif that had been identified in an independent study of nearly 1000 chronically infected individuals. These vulnerable and so-called "beneficial" regions were of low entropy overall, yet several were not predicted by stringent conservation algorithms. Consistent with this, stronger inhibition of clade-matched than mismatched viruses was observed in the majority of subjects, indicating better targeting of clade-specific than conserved epitopes. The magnitude of CD8+ T cell responses to beneficial regions, together with viral entropy and HLA class I genotype, explained up to 59% of the variation in viral inhibitory activity, with magnitude of the T cell response making the strongest unique contribution. However, beneficial regions were infrequently targeted by CD8+ T cells elicited by vaccines encoding full-length HIV proteins, when the latter were administered to healthy volunteers and HIV-positive ART-treated subjects, suggesting that immunodominance hierarchies undermine effective anti-HIV CD8+ T cell responses. Taken together, our data support HIV immunogen design that is based on systematic selection of empirically defined vulnerable regions within the viral proteome, with exclusion of immunodominant decoy epitopes that are irrelevant for HIV control

    In vivo and ex vivo percutaneous absorption of [14C]-bisphenol A in rats: a possible extrapolation to human absorption?

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    Bisphenol A (BPA) is a monomer used mainly in the synthesis of polycarbonates and epoxy resins. Percutaneous absorption is the second source of exposure, after inhalation, in the work environment. However, studies on this route of absorption are lacking or incomplete. In this study, percutaneous BPA absorption was measured in vivo and ex vivo in the rat, and ex vivo in humans. An approximately 12-fold difference in permeability between rat skin and human skin was found, with permeability being higher in the rat. In addition, inter- and intra-individual variability of up to tenfold was observed in humans. No accumulation of BPA in the skin was found during exposure. The skin clearance rate following exposure was estimated at 0.4 μg/cm²/h. Ex vivo and in vivo percutaneous absorption fluxes of BPA in the rat were in the same range (about 2.0 μg/cm²/h), suggesting that extrapolation to the in vivo situation in humans may be possible. The European tolerable daily intake (TDI) of BPA is 50 μg/kg body weight. However, many research projects have highlighted the significant effects of BPA in rodents at doses lower than 10 μg/kg/day. A 1-h occupational exposure over 2,000 cm² (forearms and hands) may lead to a BPA absorption of 4 μg/kg/day. This is 8% of the European TDI and is very close to the value at which effects have been observed in animals. This absorption must therefore be taken into account when evaluating risks of BPA exposure, at least until more relevant results on the toxicity of BPA in humans are available

    Visual and olfactory associative learning in the malaria vector Anopheles gambiae sensu stricto

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    <p>Abstract</p> <p>Background</p> <p>Memory and learning are critical aspects of the ecology of insect vectors of human pathogens because of their potential effects on contacts between vectors and their hosts. Despite this epidemiological importance, there have been only a limited number of studies investigating associative learning in insect vector species and none on Anopheline mosquitoes.</p> <p>Methods</p> <p>A simple behavioural assays was developed to study visual and olfactory associative learning in <it>Anopheles gambiae</it>, the main vector of malaria in Africa. Two contrasted membrane qualities or levels of blood palatability were used as reinforcing stimuli for bi-directional conditioning during blood feeding.</p> <p>Results</p> <p>Under such experimental conditions <it>An. gambiae </it>females learned very rapidly to associate visual (chequered and white patterns) and olfactory cues (presence and absence of cheese or Citronella smell) with the reinforcing stimuli (bloodmeal quality) and remembered the association for up to three days. Associative learning significantly increased with the strength of the conditioning stimuli used. Importantly, learning sometimes occurred faster when a positive reinforcing stimulus (palatable blood) was associated with an innately preferred cue (such as a darker visual pattern). However, the use of too attractive a cue (e.g. Shropshire cheese smell) was counter-productive and decreased learning success.</p> <p>Conclusions</p> <p>The results address an important knowledge gap in mosquito ecology and emphasize the role of associative memory for <it>An. gambiae</it>'s host finding and blood-feeding behaviour with important potential implications for vector control.</p

    Project Re•center dot Vision: disability at the edges of representation

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    The representational history of disabled people can largely be characterized as one of being put on display or hidden away. Self-representations have been a powerful part of the disability rights and culture movement, but recently scholars have analysed the ways in which these run the risk of creating a ‘single story’ that centres the experiences of white, western, physically disabled men. Here we introduce and theorize with Project Re•Vision, our arts-based research project that resists this singularity by creating and centring, without normalizing, representations that have previously been relegated to the margins. We draw from body becoming and new materialist theory to explore the dynamic ways in which positionality illuminates bodies of difference and open into a discussion about what is at stake when these stories are let loose into the world

    Search for composite and exotic fermions at LEP 2

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    A search for unstable heavy fermions with the DELPHI detector at LEP is reported. Sequential and non-canonical leptons, as well as excited leptons and quarks, are considered. The data analysed correspond to an integrated luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172 GeV and 161 GeV. The search for pair-produced new leptons establishes 95% confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2, depending on the channel. The search for singly produced excited leptons and quarks establishes upper limits on the ratio of the coupling of the excited fermio

    AMP Affects Intracellular Ca2+ Signaling, Migration, Cytokine Secretion and T Cell Priming Capacity of Dendritic Cells

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    The nucleotide adenosine-5′-monophosphate (AMP) can be released by various cell types and has been shown to elicit different cellular responses. In the extracellular space AMP is dephosphorylated to the nucleoside adenosine which can then bind to adenosine receptors. However, it has been shown that AMP can also activate A1 and A2a receptors directly. Here we show that AMP is a potent modulator of mouse and human dendritic cell (DC) function. AMP increased intracellular Ca2+ concentration in a time and dose dependent manner. Furthermore, AMP stimulated actin-polymerization in human DCs and induced migration of immature human and bone marrow derived mouse DCs, both via direct activation of A1 receptors. AMP strongly inhibited secretion of TNF-α and IL-12p70, while it enhanced production of IL-10 both via activation of A2a receptors. Consequently, DCs matured in the presence of AMP and co-cultivated with naive CD4+CD45RA+ T cells inhibited IFN-γ production whereas secretion of IL-5 and IL-13 was up-regulated. An enhancement of Th2-driven immune response could also be observed when OVA-pulsed murine DCs were pretreated with AMP prior to co-culture with OVA-transgenic naïve OTII T cells. An effect due to the enzymatic degradation of AMP to adenosine could be ruled out, as AMP still elicited migration and changes in cytokine secretion in bone-marrow derived DCs generated from CD73-deficient animals and in human DCs pretreated with the ecto-nucleotidase inhibitor 5′-(alpha,beta-methylene) diphosphate (APCP). Finally, the influence of contaminating adenosine could be excluded, as AMP admixed with adenosine desaminase (ADA) was still able to influence DC function. In summary our data show that AMP when present during maturation is a potent regulator of dendritic cell function and point out the role for AMP in the pathogenesis of inflammatory disorders
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