Inversão de funções do plano no plano aplicada ao cálculo de azeótropos

Azeotropia é um fenômeno termodinâmico onde um líquido em ebulição produz um vapor com composição idêntica. Esta situação é um desafio para a Engenharia de Separação, já que os processos de destilação exploram as diferenças entre as volatilidades relativas e, portanto, um azeótropo pode ser uma barreira para a separação. Em misturas binárias, o cálculo da azeotropia é caracterizado por um sistema não-linear do tipo 2 × 2. Um interessante e raro caso é o denominado azeotropia dupla, que pode ser verificado quando este sistema não-linear tem duas soluções, correspondendo a dois azeótropos distintos. Diferentes métodos tem sido utilizados na resolução de problemas desta natureza, como métodos estocásticos de otimização e as técnicas intervalares (do tipo Newton intervalar/bisseção generalizada). Nesta tese apresentamos a formulação do problema de azeotropia dupla e uma nova e robusta abordagem para a resolução dos sistemas não-lineares do tipo 2 × 2, que é a inversão de funções do plano no plano (MALTA; SALDANHA; TOMEI, 1996). No método proposto, as soluções são obtidas através de um conjunto de ações: obtenção de curvas críticas e de pré-imagens de pontos arbritários, inversão da função e por fim, as soluções esperadas para o problema de azeotropia. Esta metodologia foi desenvolvida para resolver sistemas não-lineares do tipo 2 × 2, tendo como objetivo dar uma visão global da função que modela o fenômeno em questão, além, é claro, de gerar as soluções esperadas. Serão apresentados resultados numéricos para o cálculo dos azeótropos no sistema benzeno + hexafluorobenzeno a baixas pressões por este método de inversão. Como ferramentas auxiliares, serão também apresentados aspectos numéricos usando aproximações clássicas, tais como métodos de Newton com técnicas de globalização e o algorítmo de otimização não-linear C-GRASP, para efeito de comparação.

A reprodução do Mapa Invertido da América do Sul nas visões críticas sobre o Sul global

O Mapa Invertido da América do Sul (1943) é um mapa diferente. Primeiro, porque não foi feito pelos cânones da ciência cartográfica, mas pelas mãos de um artista uruguaio, chamado Torres-García. Segundo, porque não utilizou a orientação convencional ao Norte, mas inverte o posicionamento do Sul para o topo da imagem. A presente pesquisa foi motivada pela visão de mundo diferenciada que esse mapa artístico apresenta, onde o objetivo é compreender os diversos contextos que reproduzem esse mapa, contribuindo para sua notoriedade até os dias atuais. Para tanto, é necessário entender os significados, os questionamentos e as ideologias expressas nessa inversão, pois contribuem na identificação com a obra em tempos além de sua elaboração. Nesse sentido, a pesquisa foi embasada em um exame bibliográfico de correntes de pensamento que propõem uma visão crítica sobre os processos de formação histórica do Sul global, destacavelmente o póscolonialismo e o pósdesenvolvimento. Tais subsídios teóricos auxiliam em um entendimento de mapa que seja tão plural quanto às visões de mundo podem ser, trilhando uma relação entre geopolítica, cartografia e arte

Perfil genético por sequenciamento e genotipagem de cepas multirresistentes do Mycobacterium tuberculosis provenientes de diversos estados brasileiros

A tuberculose multirresistente (MR) a drogas é uma séria ameaça à saúde pública devido à maiores complexidade, custo e efeitos colaterais do tratamento. Poucos estudos descreveram a epidemiologia molecular de isolados de Mycobacterium tuberculosis MR no Brasil. Neste trabalho foi investigada a diversidade genética e mutações associadas à resistência a drogas de 99 isolados MR e 7 não MR coletados em um período de 8 anos e provenientes de 12 estados brasileiros. Esta investigação foi feita através da análise do polimorfismo de fragmentos de restrição do elemento de inserção IS6110 (IS6110-RFLP), spoligotyping e sequenciamento de regiões dos genes rpoB e katG que conferem resistência aos antibióticos rifampicina e isoniazida, respectivamente. Mutações nos genes katG e rpoB foram encontradas em 90,9% e 93% dos isolados MR analisados, respectivamente. Para o gene rpoB, 91,9% das mutações estavam contidas na região RRDR de 81-pb. Um total de 51 (51.5%), 23 (23.3%) e 11 (11.1%) isolados MR apresentaram mutações nos códons 531, 526 e 516, respectivamente. Com relação ao gene katG, foram encontradas mutações em 93% dos isolados MR analisados, sendo que 7 apresentaram mutações apenas na primeira região analisada (katG1). O codon 315 da segunda região analisada do gene katG (katG2) apresentou mutações em 82.8% dos isolados MR, sendo a maioria Ser315Thr. A região katG1 apresentou mutações em 30.3% dos isolados MR sendo a maioria deleção do códon 4. Pelo spoligotyping foi possível determinar que os isolados MR deste estudo pertencem a 5 diferentes famílias (com suas subfamílias) de M. tuberculosis circulantes no Brasil, onde as mais frequentemente encontradas foram: LAM (46%), T (17%) e H (12%). Nós observamos que uma das famílias, a EAI5, carrega mutações no códon 463 do gene katG, o que não ocorre para as demais. Além disso, entre nossos isolados foi identificada um isolado pertencente à cepa Beijing (extremamente virulenta), mas este fato não é alarmante já que se tratou de apenas um caso. Através de nossos dados foram descritos novos alelos mutados para os genes rpoB e katG. Com exceção da família X2, foi identificada uma região inicial do gene katG com alta frequência de mutações nos isolados MR. A análise por IS6110-RFLP revelou que 25 isolados formaram 11 grupos genotípicos enquanto 74 mostraram um padrão único de bandas. Esta alta taxa de polimorfismo indica aquisição independente de resistência entre nossos isolados. Para a família H, foi identificada uma inversão na freqüência de ocorrência de mutações no gene rpoB, sendo o códon 516 o mais mutado, seguido pelo 526 e 531. Os resultados deste estudo fornecem informações úteis para um melhor entendimento do espectro de mutações dos isolados MR de pacientes no Brasil. Nossos resultados também se tornam úteis no desenvolvimento de testes diagnósticos de tuberculose MR e para auxiliar no rastreamento da transmissão global desta doença.

Investigation of damping effects on statistical energy analysis of coupled structures

The effects of damping on energy sharing in coupled systems are investigated. The approach taken is to compute the forced response patterns of various idealised systems, and from these to calculate the parameters of Statistical Energy Analysis model for the systems using the matrix inversion approach [1]. It is shown that when SEA models are fitted by this procedure, the values of the coupling loss factors are significantly dependent on damping except when it is sufficiently high. For very lightly damped coupled systems, varying the damping causes the values of the coupling loss factor to vary in direct proportion to the internal loss factor. In the limit of zero damping, the coupling loss factors tend to zero. This is a view which contrasts strongly with 'classical' SEA, in which coupling loss factors are determined by the nature of the coupling between subsystems, independent of subsystem damping. One implication of the strong damping dependency is that equipartition of modal energy under low damping does not in general occur. This is contrary to the classical SEA prediction that equipartition of modal energy always occurs if the damping can be reduced to a sufficiently small value. It is demonstrated that the use of this classical assumption can lead to gross overestimates of subsystem energy ratios, especially in multi-subsystem structures. © 1996 Academic Press Limited.

芍药属两物种染色体结构变异杂合性研究

芍药属由大约35个灌木和多年生草本种组成，分为三个组：牡丹组(Sect. Moutan)、北美芍药组(Sect. Onaepia)和芍药组(Sect. Paeonia)。四川牡丹(Paeonia decomposita Handel-Mazzetti)和块根芍药(P. intermedia Meyer)分别隶属于牡丹组和芍药组。在该属的所有种中，染色体基数均为 x = 5，最短的五号染色体是端部着丝粒染色体，很容易辨认。 本论文研究了块根芍药三个居群22个个体和四川牡丹两个居群13个个体的减数分裂。减数分裂异常广泛发生，以至于发现所有被研究的个体都有数量不等的桥、断片和单价体。结果表明在中期I，块根芍药第一个居群平均每个小孢子母细胞有2.17个棒状二价体和2.7个环形二价体，第二个居群平均每个细胞有2.04个棒状二价体和2.86个环形二价体，第三个居群平均每个细胞有2.21个棒状二价体和2.71个环形二价体。而在四川牡丹中，第一个居群平均每个小孢子母细胞有2.09个棒状二价体和2.81个环形二价体，第二个居群平均每个细胞有1.85个棒状二价体和3.08个环形二价体。 块根芍药第一个居群的平均减数分裂染色体构型是2n = 10 = 0.25 I + 4.87 II，第二个居群是2n = 10 = 0.20 I + 4.90 II，第三个居群是2n = 10 = 0.17 I + 4.92 II，在该种的平均构型是2n = 10 = 0.21 I + 4.89 II。四川牡丹第一个居群的平均减数分裂染色体构型是2n = 10 = 0.21 I + 4.90 II，第二个居群是2n = 10 = 0.14 I + 4.93 II，在该种的平均构型是2n = 10 = 0.20 I + 4.90 II。在块根芍药中，不同个体的配对系数变化范围在69.5%和81.07%之间，在四川牡丹中在72.97%和81.37%之间。 在后期I和末期I，出现了染色体桥、断片、落后染色体、不等分离等异常现象。最明显的减数分裂异常是后期I桥/断片。尽管在不同的居群中桥/断片异常出现的频率有所变化(块根芍药居群一是26.03%，居群二是11.67%，居群三是13.39%;四川牡丹居群一是7.59%，居群二是9%)，但是这种异常出现在所有个体中(块根芍药平均为18.67%，四川牡丹平均为7.69%)。结果表明，所有的个体都是染色体臂内倒位结构杂合体，广泛存在于野生自然居群中，可能存在某些选择优势。而且，桥的出现频率和断片的大小在个体之间是变化的，这因此表明在这两个种中存在不同的倒位。然而，这两个种在野生居群中是如何维持染色体结构杂合的，其维持机制还有待于进一步阐明，还需要更进一步的证据。 该研究还揭示了块根芍药和四川牡丹这两个种具有共同的第五号染色体减数分裂异常：与长臂相比，短臂在遗传距离和物理距离之间存在巨大的背离。短臂的遗传距离，通过交叉频率计算出来，约是长臂的三十分之一（块根芍药）。然而，物理距离用臂的比率表示，大约是长臂的三分之一，物理距离是遗传距离的十倍。 在四川牡丹红心桥居群和其它居群之间，臂比存在微小的差异，而且在芍药属不同的种内也发现了存在差异。在四川牡丹中，环形二价体(两个臂形成交叉)和棒状二价体(仅一个臂形成交叉)的比率是1.94 : 98.06，而在块根芍药中是3.42 : 96.58。在这两个种中，棒状二价体大大多于环形二价体。在第五号染色体的短臂上可能存在某些“搭车效应”，这表明第五号染色体的短臂上存在高度永久杂合，导致短臂高度保守、极为稳定。这与芍药属古老的分布格局、进化历史长可能存在某些联系。四川牡丹第五号染色体的后期I倒位桥出现频率非常低，仅为0.51 - 3.47%，平均为1.43%。而且断片长度是变化的，其变化范围在1.7 - 10.8 µm之间。

Reproduction in the protogynous black grouper Mexico (Mycteroperca bonaci (Poey)) from the southern Gulf of Mexico

An analysis was made of sexual pattern, spawning season, sizes at sexual maturation, and sex change in black grouper (Mycteroperca bonaci) from the southern Gulf of Mexico. Samples were taken between 1996 and 2000, from industrial and small-craft commercial fi sheries, in offshore and inshore waters of the continental shelf of the Yucatan Peninsula (Campeche Bank), including the shallow waters of National Marine Park Alacranes Reef. For all collected specimens (n=1229), sex and maturation condition were determined by histological analysis of the gonads. The offshore sample consisted of 75.1% females, 24.3% males, and 0.6% transitional-stage fish. All individuals collected from inshore waters were females. Gonadal structure and population structure characteristics for Campeche Bank black grouper were consistent with the characteristics of monandric protogynous hermaphrodism for a serranid fish. Sexually active males and females were observed year-round, although ripening females, with stage-III, -IV, and -V vitellogenic oocytes in the ovaries, dominated in samples taken between December and March. In addition, peak occurrence of ripe-running females with hyaline oocytes or postovulatory follicles (or both) in the ovaries was recorded in January and February. A few precocious females began spawning in October and November, and others were still in spawning condition in May and June. Fifty percent maturity of females was attained at 72.1 cm fork length (FL). Median size at sexual inversion was 103.3 cm FL, and 50% of the females measuring 111.4 cm FL had transformed into males. The southern Gulf of Mexico grouper fishery was considered deteriorated and lacked a well-defined management strategy. Results of the present study provide helpful information on black grouper reproduction in this area and could help Mexican authorities choose appropriate management strategies for this fishery, such as minimum size limit, closed fishing season, and protection of spawning aggregations.

Evolution of the black muntjac (Muntiacus crinifrons) karyotype revealed by comparative chromosome painting

The black muntjac (Muntiacus crinifrons) has an unusual karyotype of 2n = 8 in females and 2n = 9 in males. We have studied the evolution of this karyotype by hybridising chromosome-specific paints derived from flow-sorted chromosomes of the Chinese muntjac (M. reevesi, 2n = 46) to chromosomes of the black muntjac. The hybridisation pattern allowed us to infer chromosomal homologies between these two species. Tandem and centromeric fusions, reciprocal translocations, and insertions are involved in the reduction of the diploid number from 2n = 46 to 2n = 8, 9. The painting patterns further show complex chromosomal rearrangements in the male black muntjac which involve more than half the karyotype, including both sex chromosomes. Since early meiosis is reported to be normal without any visible inversion loops of the synaptonemal complex, the observed chromosomal rearrangements would lead to heterosynapsis and, therefore, leave a large fraction of the male black muntjac karyotype balanced between the two sexes.

Reciprocal chromosome painting illuminates the history of genome evolution of the domestic cat, dog and human

Domestic cats and dogs are important companion animals and model animals in biomedical research. The cat has a highly conserved karyotype, closely resembling the ancestral karyotype of mammals, while the dog has one of the most extensively rearranged mammalian karyotypes investigated so far. We have constructed the first detailed comparative chromosome map of the domestic dog and cat by reciprocal chromosome painting. Dog paints specific for the 38 autosomes and the X chromosomes delineated 68 conserved chromosomal segments in the cat, while reverse painting of cat probes onto red fox and dog chromosomes revealed 65 conserved segments. Most conserved segments on cat chromosomes also show a high degree of conservation in G-banding patterns compared with their canine counterparts. At least 47 chromosomal fissions (breaks), 25 fusions and one inversion are needed to convert the cat karyotype to that of the dog, confirming that extensive chromosome rearrangements differentiate the karyotypes of the cat and dog. Comparative analysis of the distribution patterns of conserved segments defined by dog paints on cat and human chromosomes has refined the human/cat comparative genome map and, most importantly, has revealed 15 cryptic inversions in seven large chromosomal regions of conserved synteny between humans and cats.

Karyotypic conservatism in the suborder Feliformia (Order Carnivora)

Multidirectional comparative chromosome painting was used to investigate the karyotypic relationships among representative species from three Feliformia families of the order Carnivora ( Viverridae, Hyaenidae and Felidae). Complete sets of painting probes derived from flow-sorted chromosomes of the domestic dog, American mink, and human were hybridized onto metaphases of the spotted hyena (Crocuta crocuta, 2n = 40) and masked palm civet (Paguma larvata, 2n = 44). Extensive chromosomal conservation is evident in these two species when compared with the cat karyotype, and only a few events of chromosome fusion, fission and inversion differentiate the karyotypes of these Feliformia species. The comparative chromosome painting data have enabled the integration of the hyena and palm civet chromosomes into the previously established comparative map among the domestic cat, domestic dog, American mink and human and improved our understanding on the karyotype phylogeny of Feliformia species. Copyright (C) 2005 S. Karger AG, Basel.

Aging effects on early-stage face perception: An ERP study

We compared early stages of face processing in young and older participants as indexed by ERPs elicited by faces and non-face stimuli presented in upright and inverted orientations. The P1 and N170 components were larger in older than in young participant

Far-infrared emission and absorption by hot carriers in superlattices

Some of the earliest theoretical speculation, stimulated by the growth of semiconductor superlattices, focused on novel devices based on vertical transport through engineered band structures; Esaki and Tsu promised Bloch oscillators in narrow mini-band systems and Kazarinov and Suris contemplated electrically stimulated intersubband transitions as sources of infrared radiation. Nearly twenty years later these material systems have been perfected, characterized and understood and experiments are emerging that test some of these original concepts for novel submillimetre wave electronics. Here we describe recent experiments on intersubband emission in quantum wells stimulated by resonant tunnelling currents. A critical issue at this time is devising a way to achieve population inversion. Other experiments explore 'saturation' effects in narrow miniband transport. Thermal saturation may be viewed as a precursor to Bloch oscillation if the same effects can be induced with an applied electric field.

Concentration dependence of the Er3+ visible and infrared luminescence in Y2-x Erx O3 thin films on Si

Y2-x Erx O3 thin films, with x varying between 0 and 0.72, have been successfully grown on crystalline silicon (c-Si) substrates by radio-frequency magnetron cosputtering of Y2 O 3 and Er2 O3 targets. As-deposited films are polycrystalline, showing the body-centered cubic structure of Y2 O3, and show only a slight lattice parameter contraction when x is increased, owing to the insertion of Er ions. All the films exhibit intense Er-related optical emission at room temperature both in the visible and infrared regions. By studying the optical properties for different excitation conditions and for different Er contents, all the mechanisms (i.e., cross relaxations, up-conversions, and energy transfers to impurities) responsible for the photoluminescence (PL) emission have been identified, and the existence of two different well-defined Er concentration regimes has been demonstrated. In the low concentration regime (x up to 0.05, Er-doped regime), the visible PL emission reaches its highest intensity, owing to the influence of up-conversions, thus giving the possibility of using Y2-x Er x O3 films as an up-converting layer in the rear of silicon solar cells. However, most of the excited Er ions populate the first two excited levels 4I11/2 and 4I13/2, and above a certain excitation flux a population inversion condition between the former and the latter is achieved, opening the route for the realization of amplifiers at 2.75 μm. Instead, in the high concentration regime (Er-compound regime), an increase in the nonradiative decay rates is observed, owing to the occurrence of cross relaxations or energy transfers to impurities. As a consequence, the PL emission at 1.54 μm becomes the most intense, thus determining possible applications for Y2-x Erx O 3 as an infrared emitting material. © 2009 American Institute of Physics.

Does the orbital degeneracy play any role in the high thermopower of lamellar cobaltites?

This article investigates the role of the CoO6 octahedron distortion on the electronic properties and more particularly on the high value of the Seebeck coefficient in the BiCaCoO lamellar cobaltites. Our measurements provide clues indicating that the t2g orbital degeneracy lifting has to be considered to account for the observed high temperature limit of the thermopower. They also provide experimental arguments for locating the a1g and eg′ orbitals levels on the energy scale, through the compression of the octahedron. These results are in agreement with recent ab initio calculation including the electronic correlations and concluding for the inversion of these levels as compared to the expectation from the crystal field theory. © 2007 American Institute of Physics.

Bipedal walking and running with spring-like biarticular muscles.

Compliant elements in the leg musculoskeletal system appear to be important not only for running but also for walking in human locomotion as shown in the energetics and kinematics studies of spring-mass model. While the spring-mass model assumes a whole leg as a linear spring, it is still not clear how the compliant elements of muscle-tendon systems behave in a human-like segmented leg structure. This study presents a minimalistic model of compliant leg structure that exploits dynamics of biarticular tension springs. In the proposed bipedal model, each leg consists of three leg segments with passive knee and ankle joints that are constrained by four linear tension springs. We found that biarticular arrangements of the springs that correspond to rectus femoris, biceps femoris and gastrocnemius in human legs provide self-stabilizing characteristics for both walking and running gaits. Through the experiments in simulation and a real-world robotic platform, we show how behavioral characteristics of the proposed model agree with basic patterns of human locomotion including joint kinematics and ground reaction force, which could not be explained in the previous models.

EST-based identification of genes expressed in the hypothalamus of male orange-spotted grouper (Epinephelus coioides)

The orange-spotted grouper, Epinephelus coioides, is an important marine aquaculture fish, but its large-scale aquaculture has been hindered by the rarity of natural males because it is a protogynous hermaphroditic fish. Hypothalamus-pituitary-gonad is an important endocrine axis in regulating reproduction and sex differentiation. To reveal the molecular mechanism of hypothalamic physiological functions, we performed he studies on identification of genes expressed in the hypothalamus of male orange-spotted grouper using EST and RT-PCR strategy. A total of 1006 ESTs were sequenced, and 402 (39.96%) clones were identified as known genes and 604 (60.04%) as unknown genes. The 402 clones of known gene products represent transcripts of 18 1 genes. Moreover, the expression patterns of 26 unknown genes were analyzed in various tissues, such as liver, kidney, spleen, fat, heart, muscle, pituitary, hypothalamus, telencephalon, cerebellum, midbrain, medulla oblongata, ovary and testes. Five different categories of expression patterns were observed from them. Several unknown ESTs, such as DN551996, DN551998, DN552082, and DN552070, were detected to be hypothalamus-specific, brains-specific, or hypothalamus and gonad-specific genes. Interestingly, DN551996, not only exhibiting expression differences between ovary and testis, but also showing sex-dependent differences in hypothalamus of grouper, might play significant role in grouper reproduction or sex inversion. Further functional studies on these genes will provide more information on molecule regulation mechanism of sex inversion in groupers. (c) 2006 Elsevier B.V All fights reserved.