139 research outputs found
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Survival of cultured mammalian cells irradiated at various depths in the LAMPF negative pion therapy beam
Cultured human kidney T-1 cells were irradiated in flasks or on coverslips at different depths in a water phantom using the Clinton P. Anderson Meson Physics Facility (LAMPF) negative pion beam. Studies of cell survival and division delay as a function of depth and recovery between doses indicate RBEs of 1.8 +- 0.3 and an ability of cells to recover between two doses of stopping pions. (auth
Computation of Solar Radiative Fluxes by 1D and 3D Methods Using Cloudy Atmospheres Inferred from A-train Satellite Data
The main point of this study was to use realistic representations of cloudy atmospheres to assess errors in solar flux estimates associated with 1D radiative transfer models. A scene construction algorithm, developed for the EarthCARE satellite mission, was applied to CloudSat, CALIPSO, and MODIS satellite data thus producing 3D cloudy atmospheres measuring 60 km wide by 13,000 km long at 1 km grid-spacing. Broadband solar fluxes and radiances for each (1 km)2 column where then produced by a Monte Carlo photon transfer model run in both full 3D and independent column approximation mode (i.e., a 1D model)
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Identifying causes of Western Pacific ITCZ drift in ECMWF System 4 hindcasts
The development of systematic biases in climate models used in operational seasonal forecasting adversely affects the quality of forecasts they produce. In this study, we examine the initial evolution of systematic biases in the ECMWF System 4 forecast model, and isolate aspects of the model simulations that lead to the development of these biases. We focus on the tendency of the simulated intertropical convergence zone in the western equatorial Pacific to drift northwards by between 0.5° and 3° of latitude depending on season. Comparing observations with both fully coupled atmosphere–ocean hindcasts and atmosphere-only hindcasts (driven by observed sea-surface temperatures), we show that the northward drift is caused by a cooling of the sea-surface temperature on the Equator. The cooling is associated with anomalous easterly wind stress and excessive evaporation during the first twenty days of hindcast, both of which occur whether air-sea interactions are permitted or not. The easterly wind bias develops immediately after initialisation throughout the lower troposphere; a westerly bias develops in the upper troposphere after about ten days of hindcast. At this point, the baroclinic structure of the wind bias suggests coupling with errors in convective heating, although the initial wind bias is barotropic in structure and appears to have an alternative origin
Measuring socio-demographic differences in volunteers with a value-based index: illustration in a mega event
The phenomenon of volunteering can be analysed as a consumer experience through the concept of value as a trade-off between benefits and costs. In event volunteering, both the expected value (pre-experienced) and the perceived value (post-experienced) of volunteering can be assessed. With this purpose, an online quantitative survey is conducted with a sample of 711 volunteers in a religious mega event, with questions related to five dimensions of their experience: efficiency, social value, play, spirituality and time spent. These five scales, properly tested are used for building a multidimensional index of both the expected and perceived value of the volunteer experience. ANOVAs test show significant differences on the index in both moments upon the socio-demographic profiles: negative expectations/experience balance by age, contrasted results by sex, and more experienced volunteers being more critical with the value experienced. Implications for event managers are proposed, in line with the motivation of volunteers
A global spectral library to characterize the world's soil
Soil provides ecosystem services, supports human health and habitation, stores carbon and regulates emissions of greenhouse gases. Unprecedented pressures on soil from degradation and urbanization are threatening agro-ecological balances and food security. It is important that we learn more about soil to sustainably manage and preserve it for future generations. To this end, we developed and analyzed a global soil visible-near infrared (vis-NIR) spectral library. It is currently the largest and most diverse database of its kind. We show that the information encoded in the spectra can describe soil composition and be associated to land cover and its global geographic distribution, which acts as a surrogate for global climate variability. We also show the usefulness of the global spectra for predicting soil attributes such as soil organic and inorganic carbon, clay, silt, sand and iron contents, cation exchange capacity, and pH. Using wavelets to treat the spectra, which were recorded in different laboratories using different spectrometers and methods, helped to improve the spectroscopic modelling. We found that modelling a diverse set of spectra with a machine learning algorithm can find the local relationships in the data to produce accurate predictions of soil properties. The spectroscopic models that we derived are parsimonious and robust, and using them we derived a harmonized global soil attribute dataset, which might serve to facilitate research on soil at the global scale. This spectroscopic approach should help to deal with the shortage of data on soil to better understand it and to meet the growing demand for information to assess and monitor soil at scales ranging from regional to global. New contributions to the library are encouraged so that this work and our collaboration might progress to develop a dynamic and easily updatable database with better global coverage. We hope that this work will reinvigorate our community's discussion towards larger, more coordinated collaborations. We also hope that use of the database will deepen our understanding of soil so that we might sustainably manage it and extend the research outcomes of the soil, earth and environmental sciences towards applications that we have not yet dreamed of
Quantitative magnetic resonance techniques as surrogate markers of Alzheimer’s disease
Espectroscopia de prótons na doença de Alzheimer e no comprometimento cognitivo sem demência: estudo de uma amostra comunitária
Co-occurrence of communication disorder and psychiatric disorders in maltreated children and adolescents: relationship with global functioning
Computation of Solar Radiative Fluxes by 1D and 3D Methods Using Cloudy Atmospheres Inferred from A-train Satellite Data
Proton magnetic resonance spectroscopy: clinical applications in patients with brain lesions
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