A poética de Edgar Allan Poe

O estudo abrange o início da vida literária de Edgar Allan Poe como crítico do periódico Grahams Magazine. Ao produzir resenhas sobre Nathanael Hawthorne, Poe elabora uma síntese de suas concepções a respeito do conto. Para o autor a vantagem do conto, como gênero, é que ele permite uma leitura totalizadora. O exame das resenhas de Poe torna possível uma aproximação entre a poética do autor norte-americado com a de Aristótele

COBOL as a Modern Language

The use of COBOL cripples the mind; its teaching should, therefore, be regarded as a criminal offence. - Edsger Dijkstra (1) This statement may be hyperbole, but Dijkstra\u27s view on the language reflects underlying feelings about COBOL throughout the programming world. The language was created in 1959 to allow for interactivity between computation machines.(2) More than half a century later, COBOL is still used extensively in mainframes, computers designed for large-scale calculation and record processing. Numerous factors have contributed to the longevity of COBOL, including ease of use compared to its contemporaries and an upgrade to object orientation in the 1990s.(3) This longevity has also contributed to problems with COBOL. The chief criticism is that it has become difficult to learn as other programming languages become more user-friendly.(4) COBOL software tends to be verbose, even for simple tasks. It\u27s said that the average size of a COBOL program is 600 lines of code, whereas a Java program performing the same operation should be 30 lines or fewer.(5) Difficulties with the language will only increase as the workforce knowledgeable in COBOL\u27s use retire

Procedimento construtivo e tratamento dos meios expressivos: concepções sobre o conto em Edgar Allan Poe a partir da leitura crítica de Nathaniel Hawthorne

This essay traces the poetics of the short story in Edgar Allan Poe based on his critical reviews of Nathaniel Hawthorne, at the dawn of capitalism and literary modernity. The notions of the axes of constructive procedures and of expressive means, derived from Rus- sian formalism, are applied here to Poe’s own work, which operated as a dialectical pair of Nathaniel Hawthorne.Este ensaio rastreia a poética do conto de Edgar Allan Poe a partir das resenhas críticas que fez de Nathaniel Hawthorne, no alvorecer do capitalismo e da modernidade literária. As noções de eixo dos procedimentos construtivos e eixo dos meios expressivos, derivadas do formalismo russo, são aplicadas aqui ao próprio trabalho de Edgar Allan Poe, que funcionou como par dialético de Nathaniel Hawthorne

Exocomets in the circumstellar gas disk of HD 172555

The source HD172555 is a young A7V star surrounded by a debris disk with a gaseous component. Here, we present the detection of variable absorption features detected simultaneously in the Ca II K and H doublet lines (at 3,933 and 3,968 Angstrom). We identified the presence of these absorption signatures at four different epochs in the 129 HARPS high-resolution spectra gathered between 2004 and 2011. These transient absorption features are most likely due to Falling Evaporating Bodies (FEBs, or exocomets) that produce absorbing gas observed transiting in front of the central star. We also detect a stable Ca II absorption component at the star's radial velocity. With no corresponding detection in the Na I line, the resulting very low upper limit for the NaI/CaII ratio suggests that this absorption is due to circumstellar gas.Comment: Accepted for publication in Astronomy&Astrophysics Letter

Genome-scale reconstruction and system level investigation of the metabolic network of Methylobacterium extorquens AM1

Background: Methylotrophic microorganisms are playing a key role in biogeochemical processes - especially the global carbon cycle - and have gained interest for biotechnological purposes. Significant progress was made in the recent years in the biochemistry, genetics, genomics, and physiology of methylotrophic bacteria, showing that methylotrophy is much more widespread and versatile than initially assumed. Despite such progress, system-level description of the methylotrophic metabolism is currently lacking, and much remains to understand regarding the network-scale organization and properties of methylotrophy, and how the methylotrophic capacity emerges from this organization, especially in facultative organisms. Results: In this work, we report on the integrated, system-level investigation of the metabolic network of the facultative methylotroph Methylobacterium extorquens AM1, a valuable model of methylotrophic bacteria. The genome-scale metabolic network of the bacterium was reconstructed and contains 1139 reactions and 977 metabolites. The sub-network operating upon methylotrophic growth was identified from both in silico and experimental investigations, and 13C-fluxomics was applied to measure the distribution of metabolic fluxes under such conditions. The core metabolism has a highly unusual topology, in which the unique enzymes that catalyse the key steps of C1 assimilation are tightly connected by several, large metabolic cycles (serine cycle, ethylmalonyl- CoA pathway, TCA cycle, anaplerotic processes). The entire set of reactions must operate as a unique process to achieve C1 assimilation, but was shown to be structurally fragile based on network analysis. This observation suggests that in nature a strong pressure of selection must exist to maintain the methylotrophic capability. Nevertheless, substantial substrate cycling could be measured within C2/C3/C4 inter-conversions, indicating that the metabolic network is highly versatile around a flexible backbone of central reactions that allows rapid switching to multi-carbon sources. Conclusions: This work emphasizes that the metabolism of M. extorquens AM1 is adapted to its lifestyle not only in terms of enzymatic equipment, but also in terms of network-level structure and regulation. It suggests that the metabolism of the bacterium has evolved both structurally and functionally to an efficient but transitory utilization of methanol. Besides, this work provides a basis for metabolic engineering to convert methanol into value-added products

UTILIZAÇÃO DE PRÓPOLIS PARA LEITÕES DESMAMADOS

The inclusion of antimicrobial performance enhancers in animal diets has been progressively restricted, result of a greater concern for the safety and quality of the food, increasingly stimulating the search for natural alternative additives. Thus, this study was aimed at conducting a literature review of the propolis efficiency as a substitute for conventional antibiotics used as growth promoters in the performance of weaned piglets. Although it is expected that propolis, such as antibiotics, influences pathogenic microorganisms in weaned piglets, more detailed studies should be carried out to establish minimum therapeutic parameters. In addition, the different types of propolis should be standardized, to allow a minimum standard chemical composition. The literature has demonstrated beneficial effects with the use of propolis in animal production, however, the results are divergent, mainly due to the environment of health challenge imposed on the animals studied.Antimicrobianos como melhoradores de desempenho têm seu uso cada vez mais restrito em dietas de animais, consequência de uma maior preocupação com a segurança e qualidade dos alimentos, estimulando cada vez mais a busca por aditivos alternativos naturais. Desta forma, este trabalho teve como objetivo realizar uma revisão de literatura sobre a eficiência da própolis como substituto dos antibióticos convencionais utilizados como promotores de crescimento no desempenho de leitões desmamados. Ainda que a expectativa seja de que a própolis, a exemplo dos antimicrobianos sintéticos, apresente ação aos microrganismos patógenos em leitões desmamados, estudos mais aprofundados devem ser realizados, de forma a estabelecer parâmetros terapêuticos mínimos. Além disso, os diferentes tipos de própolis devem ser padronizados a fim de permitir composição química mínima, principalmente em relação as propriedades farmacológicas. A literatura tem demonstrado efeitos benéficos na inclusão de própolis em diversas espécies de animais de interesse zootécnico, porém com resultados divergentes, principalmente em função do ambiente de desafio sanitário impostos aos animais estudados

An Analysis of Differential Delayed Mortality Experienced by Stream-type Chinook Salmon of the Snake River

In the Anadromous Fish Appendix of the US Army Corp of Engineers (USACE) Environmental Impact Statement on the Lower Snake River Hydrosystem Alternatives for recovery of Snake River salmon and steelhead (hereafter referred to as A-Fish ), the National Marine Fisheries Service (NMFS) suggested that transportation effectiveness of spring/summer chinook may have improved markedly in recent years. The NMFS conclusion was based on estimates of \u27D\u27-values (the differential delayed survival rate between transported fish and fish that migrated in-river) for 1994-1995 (NMFS, 1999). NMFS suggested, if \u27D\u27 is high (estimated in A-Fish at 0.8) and extra mortality of in-river and transported smolts is unrelated to the hydropower system, transportation options may meet recovery standards as well or better than natural river options. NMFS also suggested that further studies could reduce the uncertainty about true values of \u27D\u27 and provide greater confidence to make a decision on the alternative management action needed to recover listed Snake River salmon and steelhead. In this analysis, we demonstrate that the evidence is compatible with a wide range of ‘D’ values, but only a small portion of this distribution is as high as the A-Fish estimate. We also present evidence that the extra mortality of in-river fish is related to the hydrosystem. We analyzed a suite of plausible assumptions used in the calculation of \u27D\u27. Based on our analysis of the 1994-1996 PIT-tag data, there is a wide range of possible \u27D\u27-values. The NMFS\u27 estimate falls at the upper end of this distribution (90th – 95th percentiles). Alternative \u27D\u27-values, based on what we believe to be more reasonable assumptions, were closer to 0.48. Because \u27D\u27 is a modeled value (and not a measurement, as implied in the A-Fish), it is very sensitive to the suite of assumptions made and how the data are grouped. \u27D\u27 estimates were most sensitive to: (1) whether or not fish that were transported from downstream collection/transport sites (Lower Monumental (LMO) and McNary (MCN) dams) were included in the group of fish used to estimate transport smolt to adult return rates (SAR); and (2) how reach survival rate estimates were extrapolated down to Bonneville Dam (BON). In 1994 the ‘D’-value estimated using four collection projects was much lower than two collection projects. However, in 1995 and 1996 the difference in ‘D’ using two and four collection projects was not as dramatic as in 1994. Therefore, the estimated high ‘D’-values are mainly driven by this single assumption for one year. Based on past and proposed future transportation operations, it is unclear why fish transported at the lower two projects were excluded from the NMFS analysis. Transported fish are subjected to stress, injury, and crowding at the collection projects. In addition, the physiological state of fish may be poorly synchronized with the time of saltwater entry for transported fish. These factors could explain the higher delayed mortality experienced by transported fish as suggested by a consistently estimated ‘D’ value that is less than 1. We disagree with the NMFS assertion that “ongoing direct experiments that contrast the return rates of tagged fish that pass through the hydrosystem versus the return rates of transported fish can resolve this question in a clear and unambiguous manner”. While a few components of the \u27D\u27-value estimate are measurable, the sensitivity analysis highlights differences in assumptionsand uncertainties that are not likely resolvable in the near term. In addition, low numbers of returning adults and small numbers of smolts for wild spring/summer chinook salmon may hamper reducing the uncertainty in estimates for reach survival rates and SARs for a non-detected group. Therefore, data are unlikely to perfect our understanding of \u27D\u27 or eliminate the uncertainty in the most influential assumptions. The hypothesis of extra or delayed mortality due to hydrosystem passage has an empirical basis, as well as biological rationale. Based on recent PIT tag data we also found evidence that delayed mortality of both in-river and transported smolts was related to hydropower. More specifically, the evidence suggests that, at least for collected and bypassed smolts, there is a difference between the patterns of direct passage survival rates and SARs. Smolts first detected and transported from the downstream projects (LMO and MCN) had lower SARs than smolts collected and transported from higher up in the system. Similarly (as reported in the A-Fish), SARs of in-river smolts decreased as the number of times the fish were collected and bypassed increased. These pieces of information provide evidence that the Snake River spring summer chinook extra mortality is related to the juvenile migration hydrosystem experience. Based on results from life-cycle modeling (Marmorek and Peters 1998b), transport based management options lead to a high likelihood of recovery only when ‘D’ is high and the source of extra mortality is not related to the experience during hydrosystem passage. However, when extra mortality is hydrosystem related (which our analysis supports), the natural river options are still the most likely management action to recover these stocks, even if ‘D’ is high (which our analysis does not support). Simply studying ‘D’, if that were possible, without determining the source of extra mortality, yields little additional insight into effects of the different management actions on Snake River spring/summer chinook recovery. Given the dangerously low level ofthese populations, we do not believe it is prudent to make management decision on the configuration and operation of the Snake and Columbia hydrosystem for the next 5-20 years (i.e. delaying a decision preserves status quo configuration), based solely on one optimistic assumption about the effectiveness of past and current hydrosystem operations

Maximum Likelihood for the Multinomial Probit Model

37 pages, 1 article*Maximum Likelihood for the Multinomial Probit Model* (Natarajan, Ranjini; McCulloch, Charles E.; Kiefer, Nicholas M.) 37 page

Quantum principle of sensing gravitational waves: From the zero-point fluctuations to the cosmological stochastic background of spacetime

We carry out a theoretical investigation on the collective dynamics of an ensemble of correlated atoms, subject to both vacuum fluctuations of spacetime and stochastic gravitational waves. A general approach is taken with the derivation of a quantum master equation capable of describing arbitrary confined nonrelativistic matter systems in an open quantum gravitational environment. It enables us to relate the spectral function for gravitational waves and the distribution function for quantum gravitational fluctuations and to indeed introduce a new spectral function for the zero-point fluctuations of spacetime. The formulation is applied to two-level identical bosonic atoms in an off-resonant high-Q cavity that effectively inhibits undesirable electromagnetic delays, leading to a gravitational transition mechanism through certain quadrupole moment operators. The overall relaxation rate before reaching equilibrium is found to generally scale collectively with the number N of atoms. However, we are also able to identify certain states of which the decay and excitation rates with stochastic gravitational waves and vacuum spacetime fluctuations amplify more significantly with a factor of N². Using such favorable states as a means of measuring both conventional stochastic gravitational waves and novel zero-point spacetime fluctuations, we determine the theoretical lower bounds for the respective spectral functions. Finally, we discuss the implications of our findings on future observations of gravitational waves of a wider spectral window than currently accessible. Especially, the possible sensing of the zero-point fluctuations of spacetime could provide an opportunity to generate initial evidence and further guidance of quantum gravity

An action principle for the quantization of parametric theories and nonlinear quantum cosmology

By parametrizing the action integral for the standard Schrodinger equation we present a derivation of the recently proposed method for quantizing a parametrized theory. The reformulation suggests a natural extension from conventional to nonlinear quantum mechanics. This generalization enables a unitary description of the quantum evolution for a broad class of constrained Hamiltonian systems with a nonlinear kinematic structure. In particular, the new theory is applicable to the quantization of cosmological models where a chosen gravitational degree of freedom acts as geometric time. This is demonstrated explicitly using three cosmological models: the Friedmann universe with a massless scalar field and Bianchi type I and IX models. Based on these investigations, the prospect of further developing the proposed quantization scheme in the context of quantum gravity is discussed.Comment: 14 page