Vírus detectados em germoplasma vegetal introduzido no Brasil pelo laboratório de quarentena (2004-2007).

bitstream/CENARGEN/29614/1/cot172.pd

Envelhecimento acelerado de aguardentes vínicas na presença de fragmentos de madeira. Influência nos compostos odorantes

A tecnologia de envelhecimento tradicional, que consiste na colocação da aguardente vínica em vasilhas de madeira durante vários anos, é uma técnica morosa e onerosa. Assim, têm vindo a ser introduzidas e desenvolvidas novas técnicas, com o intuito de optimizar o processo e reduzir os custos. Uma dessas novas técnicas consiste em introduzir pedaços de madeira (aparas, toros ou outras formas) na bebida a envelhecer, condicionada em depósitos de inox. Têm sido realizados muitos estudos em vinhos, mas em aguardentes a experimentação é escassa [1, 2]. Assim, este trabalho teve como objectivo avaliar a influência da utilização de alternativas ao envelhecimento de aguardentes em vasilhas de madeira, na composição química das aguardentes obtidas, dando particular atenção aos compostos odorantes provenientes da madeira. Para tal, uma mesma aguardente vínica da Lourinhã foi submetida a um processo de envelhecimento, com três formas de madeira: aguardente colocada em vasilha de madeira (V), aguardente colocada em vasilha de inox com introdução de madeira sob a forma de dominós (D) e aguardente colocada em vasilha de inox com introdução de madeira sob a forma de tábuas (T), tendo sido colhidas amostras de aguardente, ao fim de 180 dias de envelhecimento, para análise e quantificação dos compostos odorantes. Os resultados obtidos mostram que a forma da madeira teve um efeito altamente significativo na maioria dos compostos analisados. No caso dos compostos odorantes derivados da lenhina da madeira (fenois voláteis e vanilina), os teores mais elevados foram encontrados nas aguardentes envelhecidas na presença de fragmentos (dominós ou tábuas), enquanto para os compostos odorantes derivados das hemiceluloses da madeira (ácido acético e aldeídos furânicos) os teores mais elevados foram determinados nas aguardentes envelhecidas em vasilha de madeira. Os resultados deste trabalho sugerem a possibilidade de diferenciação química das aguardentes, em função da tecnologia de envelhecimento

Sensory and chemical modifications of wine brandy aged with chestnut and oak wood

This work evaluated the sensorial and chemical modifications in brandy aged in presence of two types of wood fragments in comparison with a brandy aged in wooden barrels

GC-FID and GC-MS as a tool to screen the influence of wood ageing technologies in the brandies odourless and odourant compounds

The maturation of wine brandies in wooden barrels cause many sensory and physicochemical changes in these alcoholic beverages, namely its flavour modification. Previous work (Caldeira et al. 2008) pointed out the most potent odourant compounds of the wine aged brandies. Some of these compounds proceed from the distillate and others are extracted from the wood. In this study it was quantified, some odourless compounds, such as methanol and higher alcohols and several odorant compounds in brandies aged in presence of two types of wood fragments (staves and tablets), from two different kinds of woods (Limousin oak wood and Portuguese chestnut wood), and compared with those found in the same with brandy aged in wooden barrels. A taster panel have also profiled these brandies and evaluated their overall quality. The methanol and higher alcohols were quantified by GC-FID equipped with a fused silica capillary column of polyethylene glycol according to the official method [NP 3263, 1990]. The odorant compounds were quantified by GC-FID and identified by GC-MS. The results showed that the ageing system is the most discriminant factor, having a significant effect on the level of several odourant compounds. The wood botanical species affected few odourant compounds. The importance of odorant compounds was also demonstrated by the high linear correlations between their contents and the intensity of several sensory attributes. The results show the possibility of using the chromatographic results as a tool to discriminate brandies produced with different ageing technologies

Potencial de sequestro do carbono em solo pela incorporação de carvão das cascas de frutos da castanha-do-Brasil.

Utilizou-se um ensaio de respirometria para estimar o potencial de sequestro de carbono no solo pela incorporação de carvão das cascas de frutos da castanha-do-brasil. Os carvões produzidos a 350ºC, 450ºC e 550°C foram adicionados ao solo contendo microorganismos e paralelamente em meio abiótico, cujos frascos foram vedados para quantificação da evolução do carvão em CO2. O ensaio foi monitorado por 182 dias verificando-se taxas decrescentes de CO2, cujas curvas apresentaram formato logarítmico. Observou-se que no processo abiótico a formação de CO2 é superior quando comparada ao processo biótico, e que o carvão produzido a 550°C apresenta maior taxa de mineralização que os demais carvões. Além disso, verifica-se que todas as amostras de carvão possuem estabilidade no solo a longo prazo

Ultrasound Tracking and Closed-Loop Control of a Magnetically-Actuated Biomimetic Soft Robot

Small untethered soft robots have potential for diverse applications, particularly in constrained spaces where the use of a tethered device would be infeasible. Examples include biomedical applications such as brachytherapy, fine-needle biospy and micro-needle drug delivery. To advance soft robots towards these applications, there is a need to establish methods for tracking and control using clinically-relevant methods. This study demonstrates motion planning and magnetic control of a soft untethered robot, using ultrasound images as feedback. The closed-loop control of the Millipede soft robot is first validated using a camera-based tracker, where the deviation between the planned path and the trajectory of the robot is 1.71 mm. Afterwards, two methods for ultrasound-based tracking capable of estimating the pose of the robot are proposed, a geometric approach and a convolutional neural network (CNN), and their performance is compared using a video camera as ground truth. Following this, the CNN method replaces the camera tracker to estimate the position and orientation of the robot. The closed-loop system using ultrasound images guides the robot through the workspace while avoiding virtual obstacles, and achieves an average tracking error of 1.59 mm and an angle error of 2.24°.</p

Avaliação sensorial de doce em massa do fruto do imbuzeiro (Spondias tuberosa, Arruda).

Este trabalho teve como objetivo produzir e testar a aceitação de dois tipos de doces em massa, preparados com os frutos do imbuzeiro

Heavy Quark Symmetry Violation in Semileptonic Decays of D Mesons

The decays of $D$ mesons to $K l \nu$ and $K^* l \nu$ final states exhibit significant deviations from the predictions of heavy-quark symmetry, as one might expect since the strange quark's mass is of the same order as the QCD scale. Nonetheless, in order to understand where the most significant effects might lie for heavier systems (such as $B \to D l\nu$ and $B \to D^* l\nu$), the pattern of these deviations is analyzed from the standpoint of perturbative QCD and ${\cal O}(1/m_s)$ corrections. Two main effects are noted. First, the perturbative QCD corrections lead to an overall decrease of predicted rates, which can be understood in terms of production of excited kaonic states. Second, ${\cal O}(1/m_s)$ effects tend to cancel the perturbative QCD corrections in the case of $Kl\nu$ decay, while they have minimal effect in $K^*l\nu$ decay.Comment: 25 pages (LaTeX) + 7 pages of Postscript figures (included at end), EFI-92-3

Quantum mechanics of particles constrained to spiral curves with application to polyene chains

Context: Due to advances in synthesizing lower-dimensional materials, there is the challenge of finding the wave equation that effectively describes quantum particles moving on 1D and 2D domains. Jensen and Koppe and Da Costa independently introduced a confining potential formalism showing that the effective constrained dynamics is subjected to a scalar geometry-induced potential; for the confinement to a curve, the potential depends on the curve’s curvature function.Method: To characterize the π electrons in polyenes, we follow two approaches. First, we utilize a weakened Coulomb potential associated with a spiral curve. The solution to the Schrödinger equation with Dirichlet boundary conditions yields Bessel functions, and the spectrum is obtained analytically. We employ the particle-in-a-box model in the second approach, incorporating effective mass corrections. The π-π* transitions of polyenes were calculated in good experimental agreement with both approaches, although with different wave functions