Otimização dos parâmetros hidráulicos do solo por meio de modelagem inversa utilizando o programa "PEST".

As informações dos parâmetros hidráulicos de solo constituem em dados importantes em estudos com modelagem do fluxo de água, transporte de solutos ou contaminantes bem como em simulação de crescimento vegetal. O objetivo desse estudo foi otimizar os parâmetros hidráulicos do solo pelo método de modelagem inversa. Os solos pertencem a duas áreas experimentais conduzidos em área comercial de cana-de-açúcar. O programa PEST (Parameter ESTimation) foi utilizado com o intuito de minimizar a soma dos quadrados dos resíduos entre o conteúdo de água no solo medido nos dois experimentos pelo método gravimétrico, com o conteúdo de água no solo simulada pelo modelo SWAP/WOFOST. A variação do índice estatístico RMSE entre o conteúdo de água no solo medida em campo com o simulado pelo modelo foi semelhante em ambos os locais e em média apresentou valor de 0,0281 e 0,0274 m3 m-3. O método de modelagem inversa realizado pelo programa PEST mostrou ser eficaz na otimização dos parâmetros hidráulicos do solo em ambos os locais de estudo

A Moment-Based Polarimetric Radar Forward Operator for Rain Microphysics

There is growing interest in combining microphysical models and polarimetric radar observations to improve our understanding of storms and precipitation. Mapping model-predicted variables into the radar observational space necessitates a forward operator, which requires assumptions that introduce uncertainties into model-observation comparisons. These include uncertainties arising from the microphysics scheme a priori assumptions of a fixed drop size distribution (DSD) functional form, whereas natural DSDs display far greater variability. To address this concern, this study presents a moment-based polarimetric radar forward operator with no fundamental restrictions on the DSD form by linking radar observables to integrated DSD moments. The forward operator is built upon a dataset of > 200 million realistic DSDs from one-dimensional bin microphysical rain shaft simulations, and surface disdrometer measurements from around the world. This allows for a robust statistical assessment of forward operator uncertainty and quantification of the relationship between polarimetric radar observables and DSD moments. Comparison of "truth" and forward-simulated vertical profiles of the polarimetric radar variables are shown for bin simulations using a variety of moment combinations. Higher-order moments (especially those optimized for use with the polarimetric radar variables: the 6th and 9th) perform better than the lower-order moments (0th and 3rd) typically predicted by many bulk microphysics schemes

A Water-Soluble Iridium Photocatalyst for Chemical Modification of Dehydroalanines in Peptides and Proteins

Dehydroalanine (Dha) residues are attractive non-canonical amino acids that occur naturally in ribosomally synthesised and post-translationally modified peptides (RiPPs). Dha residues are attractive targets for selective late-stage modification of these complex biomolecules. In this work, we show the selective photocatalytic modification of dehydroalanine residues in the antimicrobial peptide nisin and in the proteins Small Ubiquitin-like Modifier (SUMO) and superfolder Green Fluorescent Protein (sfGFP). For this purpose, a new water-soluble iridium(III) photoredox catalyst was used. The design and synthesis of this new photocatalyst, [Ir(dF(CF3 )ppy)2 (dNMe3 bpy)]Cl3, is presented. In contrast to commonly used iridium photocatalysts, this complex is highly water-soluble and allows modification of peptides and proteins in water and aqueous solvents under physiologically relevant conditions and with short reaction times and low reagent and catalyst loadings. This work suggests that photoredox catalysis using this newly designed catalyst is a promising strategy to modify dehydroalanine-containing natural products and thus may have great potential for novel bioconjugation strategies

Chronic Childhood Peer Rejection is Associated with Heightened Neural Responses to Social Exclusion During Adolescence

This functional Magnetic Resonance Imaging (fMRI) study examined subjective and neural responses to social exclusion in adolescents (age 12-15) who either had a stable accepted (n = 27; 14 males) or a chronic rejected (n = 19; 12 males) status among peers from age 6 to 12. Both groups of adolescents reported similar increases in distress after being excluded in a virtual ball-tossing game (Cyberball), but adolescents with a history of chronic peer rejection showed higher activity in brain regions previously linked to the detection of, and the distress caused by, social exclusion. Specifically, compared with stably accepted adolescents, chronically rejected adolescents displayed: 1) higher activity in the dorsal anterior cingulate cortex (dACC) during social exclusion and 2) higher activity in the dACC and anterior prefrontal cortex when they were incidentally excluded in a social interaction in which they were overall included. These findings demonstrate that chronic childhood peer rejection is associated with heightened neural responses to social exclusion during adolescence, which has implications for understanding the processes through which peer rejection may lead to adverse effects on mental health over time.Pathways through Adolescenc

Cationic iron porphyrins with sodium dodecyl sulphate for micellar catalysis of cyclopropanation reactions

Here, we report that the combination of cationic iron porphyrins with sodium dodecyl sulphate (SDS) gives rise to efficient micellar catalysis of cyclopropanation reactions of styrene derivatives, using diazoacetates as carbene precursors. This simple, yet effective approach for cyclopropanations illustrates the power of micellar catalysis

Developmental pathways linking childhood temperament with antisocial behavior and substance use in adolescence : explanatory mechanisms in the peer environment

This study investigated three developmental pathways involving the peer environment that may explain how certain temperamental dispositions in childhood may become manifested in later antisocial behavior and substance use. A total of 411 (52% boys) Canadian children were followed annually from ages 6 to 15 years. The study tested whether the temperamental traits approach, negative reactivity and attention (assessed at ages 6-7 years), were associated with overt antisocial behavior, covert antisocial behavior and illicit substance use (assessed at ages 14-15 years), via poor social preference among peers, inflated social self-perception and antisocial behavior of peer-group affiliates (assessed throughout ages 8-13 years). Results indicated that negative reactivity was indirectly associated with overt antisocial behavior and substance use via poor social preference. Specifically, negative reactivity in earlier childhood predicted poor social preference in later childhood and early adolescence. This poor social standing among peers, in turn, predicted more engagement in overt antisocial behavior but less substance use in later adolescence. Over and above the influence of social preference, negative reactivity predicted engagement in all three outcomes via children’s antisocial behavior in childhood and early adolescence. Inflated social self-perception and antisocial behavior of peergroup affiliates did not mediate the link between temperament and the outcomes under scrutiny. No sex differences in developmental pathways from temperament to the outcomes were found. To further our understanding of the developmental link between childhood temperament and later antisocial behavior and substance use, we need to recognize the role of peer environmental factors, specifically poor preference among peers

Pedotransfer functions to estimate water retention parameters of soils in northeastern Brazil.

Abstract: Pedotransfer functions (PTF) were developed to estimate the parameters of the van Genuchten model (1980) to describe soil water retention curves. The data came from various sources, mainly from studies conducted by universities in Northeast Brazil, by the Brazilian Agricultural Research Corporation (Embrapa) and by a corporation for the development of the São Francisco and Parnaíba river basins (Codevasf), totaling 786 retention curves, which were divided into two data sets: 85 % for the development of PTFs, and 15 % for testing and validation, considered independent data. Aside from the development of general PTFs for all soils together, specific PTFs were developed for the soil classes Ultisols, Oxisols, Entisols, and Alfisols by multiple regression techniques, using a stepwise procedure (forward and backward) to select the best predictors. Two types of PTFs were developed: the first included all predictors (soil density, proportions of sand, silt, clay, and organic matter), and the second only the proportions of sand, silt and clay. The evaluation of adequacy of the PTFs was based on the correlation coefficient (R) and Willmott index (d). To evaluate the PTF for the moisture content at specific pressure heads, we used the root mean square error (RMSE). The PTF- predicted retention curve is relatively poor, except for the residual water content. The inclusion of organic matter as a PTF predictor improved the prediction of parameter (alfa) of van Genuchten. The performance of soil-class-specific PTFs was not better than of the general PTF. Except for the water content of saturated soil estimated by particle size distribution, the tested models for water content prediction at specific pressure heads proved satisfactory. Predictions of water content at pressure heads more negative than -0.6 m, using a PTF considering particle size distribution, are only slightly lower than those obtained by PTFs including bulk density and organic matter content. Resumo: Foram desenvolvidas funções de pedotransferência (PTFs) para estimar os parâmetros do modelo de van Genuchten (1980), utilizados para descrever curvas de retenção de água no solo. Os dados usados foram provenientes de diversas fontes, principalmente de estudos realizados na Região Nordeste pelas universidades, pela Embrapa e Codevasf, totalizando 786 curvas de retenção, que foram divididas em dois conjuntos de dados: 85 %, para desenvolvimento das PTFs, e 15 %, para teste e validação, considerados como dados independentes. Além do desenvolvimento das PTFs de caráter geral para todos os solos conjuntamente, desenvolveram-se PTFs específicas para as classes Argissolos, Latossolos, Neossolos e Planossolos, utilizando técnicas de regressão múltipla, com o uso do procedimento stepwise (forward e backward), para selecionar os melhores preditores. Dois tipos de PTFs foram desenvolvidos: o primeiro inclui todos os preditores, densidade do solo, teores de areia, silte, argila e de matéria orgânica, e o segundo, apenas com os teores de areia, silte e argila. A avaliação da adequação das PTFs foi com base no coeficiente de correlação (R) e índice de Willmott (d). Para avaliar as PTFs, para o teor de água em potenciais matriciais específicos, utilizou-se a raiz do erro médio quadrado (RMSE). A predição da curva de retenção por PTF é relativamente fraca, exceto para o teor de água residual. A inclusão do teor de matéria orgânica como preditor da PTF melhora a predição do parâmetro (alfa) de van Genuchten. Não houve melhora de desempenho das PTFs específicas por classe de solo, em comparação com uma PTF geral. Exceto no caso do teor de água do solo saturado, estimado pela distribuição granulométrica, modelos para a predição do teor de água em potenciais matriciais específicos são bons. Predições do teor de água em potenciais matriciais mais negativos do que -0,6 m, usando uma PTF contendo a distribuição granulométrica, são somente um pouco inferiores àquelas obtidas por PTFs, que incluem densidade do solo e teor de matéria orgânica