On the Influence of Magnetic Fields on the Structure of Protostellar Jets

We here present the first results of fully three-dimensional (3-D) MHD simulations of radiative cooling pulsed (time-variable) jets for a set of parameters which are suitable for protostellar outflows. Considering different initial magnetic field topologies in approximate $equipartition$ with the thermal gas, i.e., (i) a longitudinal, and (ii) a helical field, both of which permeating the jet and the ambient medium; and (iii) a purely toroidal field permeating only the jet, we find that the overall morphology of the pulsed jet is not very much affected by the presence of the different magnetic field geometries in comparison to a nonmagnetic calculation. Instead, the magnetic fields tend to affect essentially the detailed structure and emission properties behind the shocks at the head and at the pulse-induced internal knots, particularly for the helical and toroidal geometries. In these cases, we find, for example, that the $H_\alpha$ emissivity behind the internal knots can be about three to four times larger than that of the purely hydrodynamical jet. We also find that some features, like the nose cones that often develop at the jet head in 2-D calculations involving toroidal magnetic fields, are smoothed out or absent in the 3-D calculations.Comment: 13 pages, 3 figures, Accepted by ApJ Letters after minor corrections (for high resolution figures, see http://www.iagusp.usp.br/~adriano/h.tar

Magnetic Field Effects on the Head Structure of Protostellar Jets

We present the results of 3-D SPMHD numerical simulations of supermagnetosonic, overdense, radiatively cooling jets. Two initial magnetic configurations are considered: (i) a helical and (ii) a longitudinal field. We find that magnetic fields have important effects on the dynamics and structure of radiative cooling jets, especially at the head. The presence of a helical field suppresses the formation of the clumpy structure which is found to develop at the head of purely hydrodynamical jets. On the other hand, a cooling jet embedded in a longitudinal magnetic field retains clumpy morphology at its head. This fragmented structure resembles the knotty pattern commonly observed in HH objects behind the bow shocks of HH jets. This suggests that a strong (equipartition) helical magnetic field configuration is ruled out at the jet head. Therefore, if strong magnetic fields are present, they are probably predominantly longitudinal in those regions. In both magnetic configurations, we find that the confining pressure of the cocoon is able to excite short-wavelength MHD K-H pinch modes that drive low-amplitude internal shocks along the beam. These shocks are not strong however, and it likely that they could only play a secondary role in the formation of the bright knots observed in HH jets.Comment: 14 pages, 2 Gif figures, uses aasms4.sty. Also available on the web page http://www.iagusp.usp.br/preprints/preprint.html. To appear in The Astrophysical Journal Letter

Avaliação química e biológica da proteína do grão em cultivares de milho de alta qualidade protéica.

Cultivares de milho de alta qualidade protéica (QPM) desenvolvidos pela Embrapa Milho e Sorgo foram avaliados quanto ao conteúdo de aminoácidos essenciais e aproveitamento biológico da proteína, em ratos Wistar machos, recém-desmamados. Sete grupos de seis animais foram mantidos durante dez dias sob condições ambientais padronizadas, recebendo cada grupo uma das seguintes rações: a) controle a 10% e a 7% de proteína (caseína), b) aprotéica, c) experimentais com milho a 7% de proteína (QPM amarelo - BR 473, QPM branco - BR 451 e milho comum - BR 136), d) mistura arroz-feijão a 10% de proteína (1:1 em base protéica). A qualidade protéica do milho BR 473 foi semelhante à do milho BR 451 e significativamente superior (p<O,05) à do milho BR 136, segundo os índices NPR (Net Protein Ratio- 3,37; 3,54 e 2,58, respectivamente para BR 473, BR 451 e BR 136) e NPU (Net Protein Utilization - 56%,58% e 43%, respectivamente). Os milhos QPM possuem valor protéico elevado (média de 83% em relação à proteína de referência), similar ao da mistura arroz-feijão, constituindo-se em alimentos promissores para uso em programas de combate à desnutrição no Brasil, em especial para crianças de baixa renda

An atomic-level perspective of HMG-CoA-reductase: The target enzyme to treat hypercholesterolemia

UIDB/04378/2020 PTDC/QUI-QFI/31689/2017This review provides an updated atomic-level perspective regarding the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR), linking the more recent data on this enzyme with a structure/function interpretation. This enzyme catalyzes one of the most important steps in cholesterol biosynthesis and is regarded as one of the most important drug targets in the treatment of hypercholesterolemia. Taking this into consideration, we review in the present article several aspects of this enzyme, including its structure and biochemistry, its catalytic mechanism and different reported and proposed approaches for inhibiting this enzyme, including the commercially available statins or the possibility of using dimerization inhibitors.publishersversionpublishe

Classification of fermented cocoa beans (cut test) using computer vision

Fermentation of cocoa beans is a critical step for chocolate manufacturing, since fermentation influences the development of flavour, affecting components such as free amino acids, peptides and sugars. The degree of fermentation is determined by visual inspection of changes in the internal colour and texture of beans, through the cut-test. Although considered standard for evaluation of fermentation in cocoa beans, this method is time consuming and relies on specialized personnel. Therefore, this study aims to classify fermented cocoa beans using computer vision as a fast and accurate method. Imaging and image analysis provides hand-crafted features computed from the beans, that were used as predictors in random decision forests to classify the samples. A total of 1800 beans were classified into four grades of fermentation. Concerning all image features, 0.93 of accuracy was obtained for validation of unbalanced dataset, with precision of 0.85, recall of 0.81. Although the unbalanced dataset represents actual variation of fermentation, the method was tested for a balanced dataset, to investigate the influence of a smaller number of samples per class, obtaining 0.92, 0.92 and 0.90 for accuracy, precision and recall, respectively. The technique can evolve into an industrial application with a proper integration framework, substituting the traditional method to classify fermented cocoa beans

Híbridos de bananeira ornamental com potencial para paisagismo.

Ao longo dos últimos anos, a floricultura brasileira vem adquirindo notável desenvolvimento e se caracteriza como um dos mais promissores segmentos da horticultura intensiva no campo dos agronegócios nacionais (JUNQUEIRA; PEETZ, 2008). Um dos aspectos que contribui para a expansão são as condições climáticas do Brasil que favorecem o cultivo de flores, tanto de clima temperado como tropical (FRANÇA; MAIA, 2008)

A NOTE ON TRANSIENT HEAT TRANSFER PROBLEMS WITH TEMPERATURE-DEPENDENT THERMAL CONDUCTIVITY AND THERMAL DIFFUSIVITY

In this work it is presented a numerical procedure for solving transient heat transfer problems in which the thermal diffusivity is strongly dependent on the temperature, with the aid of the Kirchhoff transformation associated to an usual finite difference approach. The first step consists of eliminating the nonlinear terms associated to the derivatives with respect to the position, by means of a Kirchhoff transformation, giving rise to a partial differential equation with only one nonlinear term (involving the coefficient of the derivative with respect to the time). The advance in time is carried out assuming the thermal diffusivity evaluated at a known temperature, giving rise to a semi-implicit scheme. Comparisons between this approach and the usual hypothesis are carried out in order to illustrate the effect of the dependence between the temperature and the thermal diffusivity. Some typical results are presented, based on the (6H-SiC) Silicon Carbide properties

Structural and vibrational properties of SnxGe1-x: Modeling and experiments

The effects of composition and macroscopic strain on the structural properties and lattice vibrations of SnxGe1-x solid solutions (SSs) are investigated numerically, employing Tersoff empirical inter-atomic potentials, and experimentally. The calculations provide statistical distributions of bond lengths, pair correlation function and vibrational Raman spectra of the SSs. Using this approach, we are able to evaluate the tin-content-dependent shifts due to the local environment (i.e changes in the atomic mass and bond stiffness) and strain effects in the calculated Raman spectra and compare them to experimental data. The relative importance of the composition dependent effects of the local environment and strain for epitaxial layers of GeSn solid solutions is analysed.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Plurianual Strategic Funding UID/FIS/04650/2013. FO acknowledges the FCT PhD Grant and thanks the Institut für Halbleitertechnik, Universität Stuttgart for hospitality.info:eu-repo/semantics/publishedVersio

Management of Operational Parameters and Novel Spinneret Configurations for the Electrohydrodynamic Processing of Functional Polymers

[EN] Functional materials have become key drivers in the development of multiple high-end technologies. Electrohydrodynamic processing (EHDP) is a straightforward method to generate polymer micro- and nanostructures that can be applied to the food, pharmaceutical, environmental, and biomedical areas, among others, since these can yield materials with higher performance. Some of the EHDP's advantages over other polymer processing technologies rely on its high versatility, by which the final assembly can be modified in different ways to combine materials with multiple properties and also in different morphological structures, and the use of room processing conditions, meaning that thermolabile ingredients can be incorporated with minimal activity loss. This review provides the historical background, process basics, and the state-of-the-art of the most recent advances achieved in the EHDP technology dealing with the control of its operational parameters to optimize processability and achieve end-product quality and homogeneity. It also focuses on the newly developed modes of operation and spinneret configurations that can lead to the formation of a wide range of micro- and nanostructures with different functionalities and solve some of its current technical limitations. Finally, it also further highlights the potential applications of the resultant hierarchical functional polymer-based materials obtained by these novel EHDP methods.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and by the I&D&I AgriFood XXI project, operation number NORTE-01-0145-FEDER-000041, co-financed by the European Regional Development Fund (FEDER) under the scope of NORTE 2020 (ProgramaOperacional Regional do Norte 2014/2020). Pedro Silva is the recipient of a fellowship (SFRD/BD/130247/2017) supported by FCT. S. TorresGiner acknowledges Spanish Ministry of Science and Innovation (MICI) for the funding received during his Ramon y Cajal contract (RYC2019027784-I).Silva, PM.; Torres-Giner, S.; Vicente, AA.; Cerqueira, MA. (2022). Management of Operational Parameters and Novel Spinneret Configurations for the Electrohydrodynamic Processing of Functional Polymers. Macromolecular Materials and Engineering. 307(5):1-21. https://doi.org/10.1002/mame.202100858121307