990 resultados para Pathogen-driven selection


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Purpose - The purpose of this paper is to verify if Brazilian companies are adopting environmental requirements in the supplier selection process. Further, this paper intends to analyze whether there is a relation between the level of environmental management maturity and the inclusion of environmental criteria in the companies` selection of suppliers. Design/methodology/approach - A review of mainstream literature on environmental management, traditional criteria in the supplier selection process and the incorporation of environmental requirements in this context. The empirical study`s strategy is based on five Brazilian case studies with industrial companies. Face-to-face interviews and informal conversations are to be held, explanations made by e-mail with representatives from the purchasing, environmental management, logistics and other areas, and observation and the collection of company documents are also employed. Findings - Based on the cases, it is concluded that companies still use traditional criteria to select suppliers, such as quality and cost, and do not adopt environmental requirements in the supplier selection process in a uniform manner. Evidence found shows that the level of environmental management maturity influences the depth with which companies adopt environmental criteria when selecting suppliers. Thus, a company with more advanced environmental management adopts more formal procedures for selecting environmentally appropriate suppliers than others. Originality/value - This is the first known study to verify if Brazilian companies are adopting environmental requirements in the supplier selection process.

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Nest orientation in social insects has been intensively studied in warmer and cooler climates, particularly in the northern hemisphere. Previous studies have consistently shown that species subjected to these climatic conditions prefer to select mostly southern locations where the nests can gain direct sunlight. However, very little is known on nest orientation in tropical and subtropical social insects. We studied nest orientations initiated by swarms throughout a year in a Brazilian swarm-founding wasp, Polybia paulista von Ihering (Hymenoptera: Polistinae). Swarms selected various orientations as nest sites, but there was a particular trend in that swarms in the winter period (May-August) preferred to build northward-facing nests. This preference is opposite from that of social wasps observed in the northern hemisphere. Colonies of this species can potentially last for many years with continuous nesting, but nesting activities of colonies during the winter are severely limited due to cool temperature and a shortened day length. Northward-facing nests are warmer through the gain of direct solar heat during the winter period; consequently, choosing northward-facing sites may be advantageous for swarms in terms of a shortened brood development and shortened time needed to increase metabolic rates during warm-up for flight.

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To better comprehend the structural and biochemical underpinnings of ion uptake across the gills of true freshwater crabs, we performed an ultrastructural, ultracytochemical and morphometric investigation, and kinetically characterized the Na(+), K(+)-ATPase, in posterior gill lamellae of Dilocarcinus pagei. Ultrastructurally, the lamellar epithelia are markedly asymmetrical: the thick, mushroom-shaped, proximal ionocytes contain elongate mitochondria (41% cell volume) associated with numerous (approximate to 14 mu m(2) membrane per mu m(3) cytoplasm), deep invaginations that house the Na(+), K(+)-ATPase, revealed ultracytochemically. Their apical surface is amplified (7.5 mu m(2) mu m(-2)) by stubby evaginations whose bases adjoin mitochondria below the subcuticular space. The apical membrane of the thin, distal ionocytes shows few evaginations (1.6 mu m(2) mu m(-2)), each surrounding a mitochondrion, abundant in the cytoplasm below the subcuticular space; basolateral invaginations and mitochondria are few. Fine basal cytoplasmic bridges project across the hemolymph space, penetrating into the thick ionocytes, suggesting ion movement between the epithelia. Microsomal Na(+), K(+)-ATPase specific activity resembles marine crabs but is approximate to 5-fold less than in species from fluctuating salinities, and freshwater shrimps, suggesting ion loss compensation by strategies other than Na(+) uptake. Enzyme apparent K(+) affinity attains 14-fold that of marine crabs, emphasizing the relevance of elevated K(+) affinity to the conquest of fresh water. Western blotting and biphasic ouabain inhibition disclose two alpha-subunit isoforms comprising distinct functional isoenzymes. While enzyme activity is not synergistically stimulated by NH(4)(+) and K(+), each increases affinity for the other, possibly assuring appropriate intracellular K(+) concentrations. These findings reveal specific structural and biochemical adaptations that may have allowed the establishment of the Brachyura in fresh water. J. Exp. Zool. 313A:508-523, 2010. (C) 2010 Wiley-Liss, Inc.

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We conduct a theoretical analysis to investigate the double diffusion-driven convective instability of three-dimensional fluid-saturated geological fault zones when they are heated uniformly from below. The fault zone is assumed to be more permeable than its surrounding rocks. In particular, we have derived exact analytical solutions to the total critical Rayleigh numbers of the double diffusion-driven convective flow. Using the corresponding total critical Rayleigh numbers, the double diffusion-driven convective instability of a fluid-saturated three-dimensional geological fault zone system has been investigated. The related theoretical analysis demonstrates that: (1) The relative higher concentration of the chemical species at the top of the three-dimensional geological fault zone system can destabilize the convective flow of the system, while the relative lower concentration of the chemical species at the top of the three-dimensional geological fault zone system can stabilize the convective flow of the system. (2) The double diffusion-driven convective flow modes of the three-dimensional geological fault zone system are very close each other and therefore, the system may have the similar chance to pick up different double diffusion-driven convective flow modes, especially in the case of the fault thickness to height ratio approaching 0. (3) The significant influence of the chemical species diffusion on the convective instability of the three-dimensional geological fault zone system implies that the seawater intrusion into the surface of the Earth is a potential mechanism to trigger the convective flow in the shallow three-dimensional geological fault zone system.

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We present a controlled stress microviscometer with applications to complex fluids. It generates and measures microscopic fluid velocity fields, based on dual beam optical tweezers. This allows an investigation of bulk viscous properties and local inhomogeneities at the probe particle surface. The accuracy of the method is demonstrated in water. In a complex fluid model (hyaluronic acid), we observe a strong deviation of the flow field from classical behavior. Knowledge of the deviation together with an optical torque measurement is used to determine the bulk viscosity. Furthermore, we model the observed deviation and derive microscopic parameters.

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Whenever we plan, imagine, or observe an action, the motor systems that would be involved in preparing and executing that action are similarly engaged. The way in which such common motor activation is formed, however, is likely to differ depending on whether it arises from our own intentional selection of action or from the observation of another's action. In this study, we use time-resolved event-related functional MRI to tease apart neural processes specifically related to the processing of observed actions, the selection of our own intended actions, the preparation for movement, and motor response execution. Participants observed a finger gesture movement or a cue indicating they should select their own finger gesture to perform, followed by a 5-s delay period; participants then performed the observed or self-selected action. During the preparation and readiness for action, prior to initiation, we found activation in a common network of higher motor areas, including dorsal and ventral premotor areas and the pre-supplementary motor area (pre-SMA); the more caudal SMA showed greater activation during movement execution. Importantly, the route to this common motor activation differed depending on whether participants freely selected the actions to perform or whether they observed the actions performed by another person. Observation of action specifically involved activation of inferior and superior parietal regions, reflecting involvement of the dorsal visual pathway in visuomotor processing required for planning the action. In contrast, the selection of action specifically involved the dorsal lateral prefrontal and anterior cingulate cortex, reflecting the role of these prefrontal areas in attentional selection and guiding the selection of responses. (c) 2005 Elsevier Inc. All rights reserved.

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Numerical methods are used to simulate the double-diffusion driven convective pore-fluid flow and rock alteration in three-dimensional fluid-saturated geological fault zones. The double diffusion is caused by a combination of both the positive upward temperature gradient and the positive downward salinity concentration gradient within a three-dimensional fluid-saturated geological fault zone, which is assumed to be more permeable than its surrounding rocks. In order to ensure the physical meaningfulness of the obtained numerical solutions, the numerical method used in this study is validated by a benchmark problem, for which the analytical solution to the critical Rayleigh number of the system is available. The theoretical value of the critical Rayleigh number of a three-dimensional fluid-saturated geological fault zone system can be used to judge whether or not the double-diffusion driven convective pore-fluid flow can take place within the system. After the possibility of triggering the double-diffusion driven convective pore-fluid flow is theoretically validated for the numerical model of a three-dimensional fluid-saturated geological fault zone system, the corresponding numerical solutions for the convective flow and temperature are directly coupled with a geochemical system. Through the numerical simulation of the coupled system between the convective fluid flow, heat transfer, mass transport and chemical reactions, we have investigated the effect of the double-diffusion driven convective pore-fluid flow on the rock alteration, which is the direct consequence of mineral redistribution due to its dissolution, transportation and precipitation, within the three-dimensional fluid-saturated geological fault zone system. (c) 2005 Elsevier B.V. All rights reserved.

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We study the effects of driving a two-level atom by two intense field modes that have equal frequencies but are otherwise distinguishable; the intensity of one mode is also assumed to be greater than that of the other. We calculate first the dressed states of the system, and then its resonance fluorescence and Autler-Townes absorption spectra. We find that the energy spectrum of the doubly dressed atom consists of a ladder of doublet continua. These continua manifest themselves in the fluorescence spectrum, where they produce continua at the positions of the Mellow sideband frequencies omega(L)+/-2 Omega of the strong field, and in the Autler-Townes absorption spectrum, which becomes a two-continuum doublet.

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The steady-state resonance fluorescence spectrum of a two-level atom driven by a bichromatic field in a broadband squeezed vacuum is studied. When the carrier frequency of the squeezed vacuum is tuned to the frequency of the central spectral line, anomalous spectral features, such as hole burning and dispersive profiles, can occur at the central line. We show that these features appear for wider, and experimentally more convenient, ranges of the parameters than in the case of monochromatic excitation. ?he absence of a coherent spectral component at the central line makes any experimental attempt to observe these features much easier. We also discuss the general features of the spectrum. When the carrier frequency of the squeezed vacuum is tuned to the first odd or even sidebands, the spectrum is asymmetric and only the sidebands an sensitive to phase. For appropriate choices of the phase the linewidths or only the odd or even sidebands can be reduced. A dressed-stale interpretation is provided.

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The study investigated the social rules applicable to selection interviews, and the attributions ions made by interviewers in response to rule-breaking behaviours by candidates. Sixty personnel specialists (31 males and 29 females) participated in the main study which examined their perceptions of social rules and attributions about rule breaking in their work experience. They listened to audiotapes of actual selection interviews, and made judgments about hireability communication competence, and specific social rules. Results indicated that interview rules could be categorized into two groups: specific interview presentation skills and general interpersonal competence. While situational attributions were more salient in explaining the breaking of general interpersonal competence rules, internal attributions (ability, effort) were more salient explanations for the breaking of more specific interview rules (with the exception of the preparation rule where lack of effort was the most likely explanation for rule breaking). Candidates previously judged as competent communicators were rated more favourably on both global and specific measures of rule-following competence, as well as on hireability. The theoretical and practical implications of combining social rules and attribution theory in the study of selection interviews are discussed.

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Under the conditions of the rotating wave approximation (RWA), a transition strongly driven by a resonant oscillating field displays the well known symmetric Autler-Townes doublet. However, if the counter-rotating component, neglected in the RWA, is taken into account, the Bloch-Siegert shift gives rise to an Autler-Townes doublet of unequal intensity even in the case of a resonant driving field. This effect is investigated theoretically in a V-shaped three-level double-resonance configuration and the results are presented in this paper. An interesting observation is that the level of asymmetry not only depends on the driving-field intensity but also on the characteristics of the driven system including relaxation rates and equilibrium population distributions.

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Fifty-four Large White gilts were used to determine the effect of body composition at selection (145 d of age) on the onset of puberty and subsequent reproductive development until 202 d of age. Gilts were assigned to one of three groups based on their backfat depth at selection: 10 to 12 mm (L), 13 to 15 mm (M), and 16 to 18 mm (F). All of the F gilts, 92% of the M gilts, and 67% of the L gilts reached puberty by slaughter at 202 d of age. Data from a subgroup (first 67% to reach puberty in each group; L = Lp, M = Mp, and F = Fp) was also used. The M (Mp) and F (Fp) gilts reached puberty at 172 d (166 d) and 170 d (166 d) of age, respectively, but the L (Lp) gilts at 184.5 d were 12 d (18 d) older than M(P < .05), Mp(P < .001), and F(P < .01), Fp (P < .001) gilts. The Lp (97.68 kg) and Mp (98.33 kg) gilts were lighter (P < .01) than Fp (108.72 kg) gilts at puberty. There were no differences (P < .05) among the L, M, and F gilts in terms of backfat depth or weight at puberty. The L (Lp) gilts had a mean of 1.16 (1.75) estrous cycles, which was lower (P < .01) than for M (Mp) and (P < .01) F (Fp) gilts, with 1.96 (2.29) and 2.25 (2.33) cycles, respectively. L (Lp) gilts had fewer (P < .05) follicles, 13.14 (12.63), than either M (Mp), 19.08 (18.71), or F (Fp), 18.25 (17.42) gilts. The number of corpora lutea was not influenced (P > .05) by grouping at selection, but Fp gilts had fewer (P < .05) corpora lutea than Mp or Fp gilts. Live weight at slaughter was not influenced (P > .10) by grouping at selection or subgrouping at puberty. The L gilts with a mean of 18.05 mm of backfat at slaughter were leaner (P < .05) than the F (21.66 mm) but not (P > .10) the M gilts (19.41 mm). Subgrouping had no effect. Fat deposition and protein deposition were higher (P < .05) in those animals that attained puberty. We conclude that the rate of fat and protein deposition seems to be one of the determinants of puberty attainment.

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Functional magnetic resonance imaging (fMRI) based on BOLD signal has been used to indirectly measure the local neural activity induced by cognitive tasks or stimulation. Most fMRI data analysis is carried out using the general linear model (GLM), a statistical approach which predicts the changes in the observed BOLD response based on an expected hemodynamic response function (HRF). In cases when the task is cognitively complex or in cases of diseases, variations in shape and/or delay may reduce the reliability of results. A novel exploratory method using fMRI data, which attempts to discriminate between neurophysiological signals induced by the stimulation protocol from artifacts or other confounding factors, is introduced in this paper. This new method is based on the fusion between correlation analysis and the discrete wavelet transform, to identify similarities in the time course of the BOLD signal in a group of volunteers. We illustrate the usefulness of this approach by analyzing fMRI data from normal subjects presented with standardized human face pictures expressing different degrees of sadness. The results show that the proposed wavelet correlation analysis has greater statistical power than conventional GLM or time domain intersubject correlation analysis. (C) 2010 Elsevier B.V. All rights reserved.

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Background: There are few studies on HIV subtypes and primary and secondary antiretroviral drug resistance (ADR) in community-recruited samples in Brazil. We analyzed HIV clade diversity and prevalence of mutations associated with ADR in men who have sex with men in all five regions of Brazil. Methods: Using respondent-driven sampling, we recruited 3515 men who have sex with men in nine cities: 299 (9.5%) were HIV-positive; 143 subjects had adequate genotyping and epidemiologic data. Forty-four (30.8%) subjects were antiretroviral therapy-experienced (AE) and 99 (69.2%) antiretroviral therapy-naive (AN). We sequenced the reverse transcriptase and protease regions of the virus and analyzed them for drug resistant mutations using World Health Organization guidelines. Results: The most common subtypes were B (81.8%), C (7.7%), and recombinant forms (6.9%). The overall prevalence of primary ADR resistance was 21.4% (i.e. among the AN) and secondary ADR was 35.8% (i.e. among the AE). The prevalence of resistance to protease inhibitors was 3.9% (AN) and 4.4% (AE); to nucleoside reverse transcriptase inhibitors 15.0% (AN) and 31.0% (AE) and to nonnucleoside reverse transcriptase inhibitors 5.5% (AN) and 13.2% (AE). The most common resistance mutation for nucleoside reverse transcriptase inhibitors was 184V (17 cases) and for nonnucleoside reverse transcriptase inhibitors 103N (16 cases). Conclusions: Our data suggest a high level of both primary and secondary ADR in men who have sex with men in Brazil. Additional studies are needed to identify the correlates and causes of antiretroviral therapy resistance to limit the development of resistance among those in care and the transmission of resistant strains in the wider epidemic.