142 research outputs found
Neuronal Distortions of Reward Probability without Choice
Reward probability crucially determines the value of outcomes. A basic phenomenon, defying explanation by traditional decision theories, is that people often overweigh small and underweigh large probabilities in choices under uncertainty. However, the neuronal basis of such reward probability distortions and their position in the decision process are largely unknown. We assessed individual probability distortions with behavioral pleasantness ratings and brain imaging in the absence of choice. Dorsolateral frontal cortex regions showed experience dependent overweighting of small, and underweighting of large, probabilities whereas ventral frontal regions showed the opposite pattern. These results demonstrate distorted neuronal coding of reward probabilities in the absence of choice, stress the importance of experience with probabilistic outcomes and contrast with linear probability coding in the striatum. Input of the distorted probability estimations to decision-making mechanisms are likely to contribute to well known inconsistencies in preferences formalized in theories of behavioral economics
Compton reflection in AGN with Simbol-X
AGN exhibit complex hard X-ray spectra. Our current understanding is that the
emission is dominated by inverse Compton processes which take place in the
corona above the accretion disk, and that absorption and reflection in a
distant absorber play a major role. These processes can be directly observed
through the shape of the continuum, the Compton reflection hump around 30 keV,
and the iron fluorescence line at 6.4 keV. We demonstrate the capabilities of
Simbol-X to constrain complex models for cases like MCG-05-23-016, NGC 4151,
NGC 2110, and NGC 4051 in short (10 ksec) observations. We compare the
simulations with recent observations on these sources by INTEGRAL, Swift and
Suzaku. Constraining reflection models for AGN with Simbol-X will help us to
get a clear view of the processes and geometry near to the central engine in
AGN, and will give insight to which sources are responsible for the Cosmic
X-ray background at energies above 20 keV.Comment: 4 pages, 1 figure, to appear in the proceedings of the second
Simbol-X Symposium "Simbol-X - Focusing on the Hard X-ray Universe", AIP
Conf. Proc. Series, P. Ferrando and J. Rodriguez ed
Origin and residence time of groundwater in the shallow coastal aquifer of eastern Dahomey Basin, Southwestern Nigeria, using δ18O and δD isotopes
This study employed stable isotopes of δ18O and δ2H in conjunction with other hydrological parameters to understand the origin, inferred residence time, and seasonal effect of groundwater in the shallow aquifers of the eastern Dahomey Basin. A total of 230 groundwater samples (97 in the wet season and 133 in the dry season) were collected from the borehole and shallow aquifer between May 2017 and April 2018. Groundwater analysis included major ions and δ18O and δ2H, isotopes data in precipitation from three selected Global Network of Isotope in Precipitation (GNIP) stations across West Africa, Douala in Cameroon, Cotonou in Republic of Benin, and Kano in Nigeria were used in comparative analysis. Results of the hydrochemical model revealed Ca-HCO3 and Na-Cl as dominant water types with other mixing water types such as Ca–SO4, Ca–Cl, Na–SO4, and K–Mg–HCO3, which characterised early stage of groundwater transformation as it infiltrates through vadose zone into the aquifer. δ18O and δ2H precipitation data from the three stations plotted along with the groundwater samples indicate recent meteoric water origin, with little effect of evaporation during the dry season. The plot of Total Dissolved Solids (TDS) against δ18O showed clustering of the water samples between the recharge and the evaporation zone with dry season samples trending towards increased TDS, which is an indication of the subtle effect of evaporation during this period. Tracing groundwater types along the flow paths within the basin is problematic and attributed to the heterogeneity of the aquifer with anthropogenic influences. Moreover, a comparison of the δ18O and δ2H isotopic compositions of groundwater and precipitation in the three selected stations, with their respective deuterium excess (D-excess) values established low evapotranspiration induced isotope enrichment, which could be due to higher precipitation and humidity in the region resulting in low isotope fractionation; hence, little effect of seasonal variations. The study, therefore, suggested groundwater recharge in the shallow aquifer in the eastern Dahomey Basin is of meteoric origin with a short residence time of water flows from soils through the vadose zone to the aquifers
Perception of health risks in Lao market vendors
Wet markets are a critical part of South-East Asian culture and economy. However, their role in circulation and transmission of both endemic and emerging disease is a source of concern in a region considered a hotspot of disease emergence. In the Lao People's Democratic Republic (Lao PDR, Laos), live and dead wild animals are frequently found in wet markets, despite legislation against the bushmeat trade. This is generally considered to increase the risk of disease transmission and emergence, although whether or not wildlife vendors themselves have indeed increased incidence of zoonotic disease has rarely been assessed. In preparation for a future longitudinal study of market vendors investigating vendors’ exposure to zoonotic pathogens, we conducted a pilot survey of Lao market vendors of wildlife meat, livestock meat and vegetables, to identify demographic characteristics and potential control groups within markets. We also investigated baseline risk perception for infectious diseases among market vendors and assessed the association between risk perception and risk mitigation behaviours. The surveys conducted with 177 vendors revealed similar age, sex, ethnic background and geographical origin between vendor types, but differences in professional background and work history for livestock meat vendors. The perception of disease risk was very low across all vendors, as was the reported use of personal protective equipment, and the two appeared unrelated. Personal risk discounting and assumptions about transmission routes may explain this lack of association. This information will help inform the development of future research, risk communication and risk mitigation policy, especially in the light of the COVID-19 pandemic
Microbial community of the deep-sea brine Lake <em>Kryos </em>seawater-brine interface is active below the chaotropicity limit of life as revealed by recovery of mRNA
Within the complex of deep, hypersaline anoxic lakes (DHALs) of the Mediterranean Ridge we identified a new, unexplored DHAL and named it "Lake Kryos" after a nearby depression. This lake is filled with MgCl2-rich, athalassohaline brine (salinity >470 practical salinity units), presumably formed by the dissolution of Messinian bischofite. Compared to the DHAL Discovery, it contains elevated concentrations of kosmotropic sodium and sulfate ions, which are capable of reducing the net chaotropicily of MgCl2-rich solutions. The brine of Lake Kryos may therefore be biologically permissive at MgCl2 concentrations previously considered incompatible with life. We characterized the microbiology of the seawater-Kryos brine interface and managed to recover mRNA from the 2.27-3.03 M MgCl2 layer (equivalent to 0.747-0.631 water-activity) thereby expanding the established chaotropicity window-for-life. The primary bacterial taxa present there were KB1 candidate division and DHAL-specific group of organisms, distantly related to Desulfohalobium. Two euryarchaeal candidate divisions MSBL1 and HC1, detected in minority in the overlaying layers, accounted for more than 85% of the rRNA-containing archaeal clones analyzed in 2.27-3.03 M MgCl2 layer. These findings shed light on the plausibility of life in highly chaotropic environments, geochemical windows for microbial extremophiles, and have implications for habitability elsewhere in the Solar System
Studies of a genetic variant in HK1 in relation to quantitative metabolic traits and to the prevalence of type 2 diabetes
Update on the third international stroke trial (IST-3) of thrombolysis for acute ischaemic stroke and baseline features of the 3035 patients recruited
Intravenous recombinant tissue plasminogen activator (rtPA) is approved in Europe for use in patients with acute ischaemic stroke who meet strictly defined criteria. IST-3 sought to improve the external validity and precision of the estimates of the overall treatment effects (efficacy and safety) of rtPA in acute ischaemic stroke, and to determine whether a wider range of patients might benefit
Memórias da Infância e da Educação: abordagens eliasianas sobre as mulheres
Relações sociais entre indivíduos estão pautadas pela experiência de educação e formação que cada um traz consigo ao longo da vida, pelo modo como se constituem individual e coletivamente. A partir de Elias e da metodologia da história oral, o objetivo foi buscar nas memórias de infância de sete mulheres, professoras de crianças, nascidas entre 1950 e 1970, a formação e a educação que se constituiu na infância em espaços privados e domésticos. Apreendeu-se que a escolha profissional tem vínculos com a educação feminina, normatizada por regras de controle e civilidade
Traditional Excluding Forces: A Review of the Quantitative Literature on the Economic Situation of Indigenous Peoples, Afro-Descendants, and People Living with Disability
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