EDITORIAL

The need for diversification of the global energy grid is present in the speeches of most governments, the motivation of scientists and the perception of a growing segment of the population. Even so, the dependence on non-renewable fuels, such as fossil fuels, has been increasing progressively due to the rapid global growth, rising consumption and increasing purchasing power of the population. Besides searching global solutions to resolve the energy quest, efforts must be directed to short-term actions, taking advantage of the available scientific and technological knowledge to improve the performance of existing systems and in use today. Improving the efficiency of cooling systems, which are responsible for much of the world electricity consumption through intelligent control of compressors can reduce up to 50% electricity consumption, and thus provide economic and strategic advantages to countries that encourage this type of initiative. Likewise, the reduction of electricity for domestic heating or showering can be obtained by waste heat recovery, solar heating or the use of heat pumps with immersed condensers, among others, contributing to the reduction of electric energy consumption. A challenge to be overcome is the popularization of such technologies in the form of final product at affordable costs. Also, for popular use, it is the important the interest of nation leaders in order to drive the use of those technologies through tax incentives and public policies. Other advances could be achieved by the use and improvement of biotechnological processes, coupling the treatment of emissions and effluents to the production of biofuels, as well as high aggregated value products. Through exergy analysis, thermoeconomics, mathematical modeling, simulation and optimization, thermal engineering is able to contribute to the efficient coupling of such different biotechnological processes and contribute to decreasing dependence on fossil fuels

Molecular kinetics of solid and liquid CHCl3_3

We present a detailed analysis of the molecular kinetics of CHCl$_3$ in a range of temperatures covering the solid and liquid phases. Using nuclear quadrupolar resonance we determine the relaxation times for the molecular rotations in solid at pre-melting conditions. Molecular dynamics simulations are used to characterize the rotational dynamics in the solid and liquid phases and to study the local structure of the liquid in terms of the molecular relative orientations. We find that in the pre-melting regime the molecules rotate about the C-H bond, but the rotations are isotropic in the liquid, even at supercooled conditions.Comment: Chemical Physics Letter (in press). 14 pages, 7 figure

DETERMINATION OF OPTIMAL ALGAE CONCENTRATION FOR CONTINUOUS GROWTH OF Scenedesmus sp. IN CHU AND MODIFIED CHU MEDIA

The high cost of production in the cultivation of microalgae in photobioreactors is a barrier to be overcome, therefore is necessary to search to reduce the cost of cultivation. The objectives of this work are to compare the growth of the microalgae Scenedesmus sp. being cultivated in CHU medium and in an alternative medium composed mainly of fertilizer and to establish guidelines for growth under continuous mode. The research approach consisted on growing the microalgae in Erlenmeyer type photobioreactors and producing thegrowth curves for both media. The comparisons between the two, were made based upon three parameters: dry biomass, absorbance, and total lipid quantity. The experiments were made in triplicates in order to quantify the uncertainty in the measurements. The comparison of the cultivation in both media suggest that the modification of the chemical nutrients by fertilizer did not produce significant changes in the number of cells, dry biomass and lipids. In spite of that, the modification resulted in 20% cost reduction in the growth medium. In this way, the substitution of conventional nutrients by fertilizers, constitute an interesting alternative for the production of biomass from microalgae leading to a cost reduction. The results are used to develop strategies for continuous growth

A new Fermi smearing approach for scattering of multi-GeV electrons by nuclei

The cross section for electron scattering by nuclei at high momentum transfers is calculated within the Fermi smearing approximation (FSA), where binding effects on the struck nucleon are introduced via the relativistic Hartree approximation (RHA). The model naturally preserves current conservation, since the response tensor for an off-shell nucleon conserves the same form that for a free one but with an effective mass. Different parameterizations for the inelastic nucleon structure function, are analyzed. The smearing at the Fermi surface is introduced through a momentum distribution obtained from a perturbative nuclear matter calculation. Recent CEBAF data on inclusive scattering of 4.05 GeV electrons on $^{56}$Fe are well reproduced for all measured geometries for the first time, as is evident from the comparison with previous calculations.Comment: 8 pages in Revtex4 style, 6 eps figures, to appear in Physical Review

System and market failures: the unavailability of magnesium sulphate for the treatment of eclampsia and pre-eclampsia in Mozambique and Zimbabwe.

Low cost and effective drugs, such as magnesium sulphate, need to be included in initiatives to improve access to essential medicines in Afric

Gender Differences in Acute Ischemic Stroke Treatment

Introduction: In order to personalize stroke treatment, it is important to know if there are differences between genders in clinical features, acute phase treatment and outcomes. Material and Methods: Longitudinal retrospective study that included patients with ischemic stroke, admitted in a stroke unit during a 30 months period and treated with throm bectomy with or without thrombolysis. The objective was to assess gender differences. Results: Of 594 patients included, 50% were women. At admission, women had higher median age (78 vs 73 years), higher modified Rankin Score (mRS) and higher median Na tional Institutes of Health Stroke Scale (NIHSS). No gender differences were found in treatment type, median time be tween symptoms onset and computed tomography, between computed tomography and thrombolysis and with respect to revascularization success. Disability expressed by mRS and mortality at 3 months were similar between genders. More women had atrial fibrillation (AF) (51% vs 35%), nevertheless, less women with known AF were receiving anticoagulant ther apy before the event, compared to men (38% vs 52%). Discussion: Even if women were older and had worse pre morbid functional status, no gender differences were evident with regard to acute phase treatment efficacy and medium term outcomes. Conclusion: In women, age should not limit acute phase treatment of stroke and decisions should be individualizedIntrodução: Na abordagem personalizada do acidente vascular cerebral (AVC) é importante definir se existem diferenças de género relativamente às caraterísticas clínicas, tratamento de fase aguda e resultados. Material e Métodos: Estudo longitudinal retrospetivo que incluiu doentes com AVC isquémico admitidos na Unidade Cerebro Vascular, durante 30 meses, tratados com trombectomia com ou sem trombólise prévia, com o objetivo de avaliar diferenças de género. Resultados: De 594 doentes, 50% eram mulheres apresentando, à admissão, idade mediana maior (78 vs 73 anos), maior pontuação na escala modificada de Rankin (mRS) e na National Institutes of Health Stroke Scale (NIHSS). Não houve diferenças no tipo de tratamento, no tempo mediano entre o início dos sintomas e tomografia computadorizada (TC), entre o tempo TC-trombólise ou na eficácia da revascularização. A disabilidade expressa pelo valor de mRS e a mortalidade aos 3 meses foram sobreponíveis entre géneros. Mais mulheres sofriam de fibrilhação auricular (FA) (51% vs 35%), no entanto menos mulheres com FA conhecida recebiam terapêutica anticoagulante antes do evento, comparativamente aos homens (38% vs 52%). Discussão: Apesar das mulheres apresentarem idade mais elevada e maior grau de dependência, não existiram diferenças de género na eficácia do tratamento de fase aguda nem nos resultados a médio prazo. Conclusão: No género feminino, a idade não deve constituir uma limitação à realização de terapêutica de fase aguda do AVC.info:eu-repo/semantics/publishedVersio

EDITORIAL

The population growing awareness regarding the use of fossil fuels, especially with respect to correlated environmental issues, led to an increased interest in renewable energy sources in the last decade. Around 200 years ago, biomass lost its historic leadership as a source for coal production. Next, it was seen the rapid growth in the use of petroleum and natural gas, and in this way, the use of biomass was limited particularly to agricultural regions. Currently, due to the responsible use of forests and large areas of reforestation, the use of biomass has conquered international attention and the demand for using wood-based materials is increasing. The biomass is not restricted to wood products, but also to any product of biological origin, which could be utilized as fuel, or for other industrial purpose and, in addition, has the advantage of being renewable. The existing challenges are the development of efficient productive chains around a product and total use of the material, including the use of the generated residuals, and the verticalisation of industrial plants. Therefore, the Thermal Engineering community could contribute to the development of technologies for coupling processes such as conversion of residuals into products of commercial value or their use for power generation. There is much opportunity for improvement in the wood, sugar cane or soybean industries, considering that all of them use heat to convert the substrates into products. Replacing natural gas or electricity used to generate heat by renewable sources such as residual biomass pellets without loss of efficiency could greatly increase the energetic efficiency of a plant, as well as reduce environmental impact

Tillage system effect on the epidemic of soybean brown spot.

Six field experiments were carried out during the summers of 1997 to 2003 to evaluate disease progress of soybean brown spot caused by Septoria glycines considering two tillage systems, conventional and no-tillage (wheat was cultivated during winter in all plots). Two logistic models were fitted to the disease progress data: (i) a logistic model with constant disease progress rate r [y=1/(1+(1/y0-1)exp(-rt)), where y0 is the initial disease level at time t=0] and (ii) a logistic model with an exponentially increasing progress rate r(t)=r0 ebt [y=1/(1+(1/y0-1) exp(r0/b(1-ebt))), where r0 is the initial progress rate at time t=0, b the rate increasing parameter, and y0 again the initial disease level]. The logistic model with constant rate underestimated disease incidence on the first disease assessment in nine out of twelve epidemics. The logistic model with an increasing rate gave a better fit to all disease progress curves (R2 between 0.90 and 0.99; no pattern in the residuals). According to this model, y0 was in most cases (four out of six) significantly smaller in the plots with no-tillage compared with conventional tillage, but no differences were detected in the initial rate parameter r0 and the rate increasing parameter b (with one exception). It is proposed that these results are due to higher susceptibility of old leaflets compared with young leaflets, as demonstrated by artificial inoculation: In four laboratory experiments the mean brown spot severity was 16.7 % on old leaflets but only 3.9 % on young leaflets

Prediction of stable walking for a toy that cannot stand

Previous experiments [M. J. Coleman and A. Ruina, Phys. Rev. Lett. 80, 3658 (1998)] showed that a gravity-powered toy with no control and which has no statically stable near-standing configurations can walk stably. We show here that a simple rigid-body statically-unstable mathematical model based loosely on the physical toy can predict stable limit-cycle walking motions. These calculations add to the repertoire of rigid-body mechanism behaviors as well as further implicating passive-dynamics as a possible contributor to stability of animal motions.Comment: Note: only corrections so far have been fixing typo's in these comments. 3 pages, 2 eps figures, uses epsf.tex, revtex.sty, amsfonts.sty, aps.sty, aps10.sty, prabib.sty; Accepted for publication in Phys. Rev. E. 4/9/2001 ; information about Andy Ruina's lab (including Coleman's, Garcia's and Ruina's other publications and associated video clips) can be found at: http://www.tam.cornell.edu/~ruina/hplab/index.html and more about Georg Bock's Simulation Group with whom Katja Mombaur is affiliated can be found at http://www.iwr.uni-heidelberg.de/~agboc

Tat-SF1 Is Not Required for Tat Transactivation but Does Regulate the Relative Levels of Unspliced and Spliced HIV-1 RNAs

.To directly address the involvement of Tat-SF1 in HIV-1 gene expression, we depleted Tat-SF1 in HeLa cells by conventional expression of shRNAs and in T- Rex -293 cells containing tetracycline-inducible shRNAs targeting Tat-SF1. We achieved efficient depletion of Tat-SF1 and demonstrated that this did not affect cell viability. HIV-1 infectivity decreased in Tat-SF1-depleted cells, but only when multiple rounds of infection occurred. Neither Tat-dependent nor basal transcription from the HIV-1 LTR was affected by Tat-SF1 depletion, suggesting that the decrease in infectivity was due to a deficiency at a later step in the viral lifecycle. Finally, Tat-SF1 depletion resulted in an increase in the ratio of unspliced to spliced viral transcripts.Tat-SF1 is not required for regulating HIV-1 transcription, but is required for maintaining the ratios of different classes of HIV-1 transcripts. These new findings highlight a novel, post-transcriptional role for Tat-SF1 in the HIV-1 life cycle