34 resultados para basis sets
em Scielo Saúde Pública - SP
Resumo:
This review has tried to collect and correlate all the various equations for the g matrix of strong field d5 systems obtained from different basis sets using full electron and hole formalism calculations. It has corrected mistakes found in the literature and shown how the failure to properly take in symmetry boundary conditions has produced a variety of apparently inconsistent equations in the literature. The review has reexamined the problem of spin-orbit interaction with excited t4e states and finds that the earlier reports that it is zero in octahedral symmetry is not correct. It has shown how redefining what x, y, and z are in the principal coordinate system simplifies, compared to previous methods, the analysis of experimental g values with the equations.
Resumo:
This article introduces a simplified model for the theoretical study of the physical adsorption process of gaseous He on the planes (100) and (111) of the solid Xe matrix, whose crystalline structure is face centered cubic (fcc). The Ab initio calculations were carried out at the MP2 level of theory employing basis sets obtained through the Generator Coordinate Method, where the core electrons were represented by a pseudopotential. The calculated adsorption energies for the (100) and (111) faces are 5,39 and 4,18 kJ/mol, respectively. This simplified model is expected to be suitable for treating complex systems of applied interest.
Resumo:
The ONIOM method was used to calculate the proton affinities (PA) of n-alkylamines (CnH2n+1NH2, n = 3 to 6, 8, 10, 12, 14, 16 and 18). The calculations were carried out at several levels (HF, MP2, B3LYP, QCISD(T), ...) using Pople basis sets and at the QCISD(T) level using basis sets developed by the generator coordinate method (GCM) and adapted to effective core potentials. PAs were also obtained through the GCM and high level methods, like ONIOM[QCISD(T)/6-31+G(2df,p):MP2/6-31G+G(d,p))//ONIOM[MP2/6-31+G(d,p):HF/6-31G]. The average error using the GCM, with respect to experimental data, was 3.4 kJ mol-1.
Resumo:
Composite methods using ONIOM and different basis sets have been used to calculate proton and electron affinities for a set of alcohols at QCISD(T)/6-311++G(2df,p) level of theory. The study was carried out considering HF, MP2 and DFT (25 exchange correlation functional) methods. The calculation performed at ONIOM2(QCISD(T)/6-311++G(2df,p):HF/6-31G(d))//ONIOM2(O3LYP/6-31G(d):HF/6-31G(d)) resulted in the smallest average absolute deviation for AP and AE, 4,75 kJ/mol e 0,43 eV, respectively.
Resumo:
Coronary artery disease (CAD) is a worldwide leading cause of death. The standard method for evaluating critical partial occlusions is coronary arteriography, a catheterization technique which is invasive, time consuming, and costly. There are noninvasive approaches for the early detection of CAD. The basis for the noninvasive diagnosis of CAD has been laid in a sequential analysis of the risk factors, and the results of the treadmill test and myocardial perfusion scintigraphy (MPS). Many investigators have demonstrated that the diagnostic applications of MPS are appropriate for patients who have an intermediate likelihood of disease. Although this information is useful, it is only partially utilized in clinical practice due to the difficulty to properly classify the patients. Since the seminal work of Lotfi Zadeh, fuzzy logic has been applied in numerous areas. In the present study, we proposed and tested a model to select patients for MPS based on fuzzy sets theory. A group of 1053 patients was used to develop the model and another group of 1045 patients was used to test it. Receiver operating characteristic curves were used to compare the performance of the fuzzy model against expert physician opinions, and showed that the performance of the fuzzy model was equal or superior to that of the physicians. Therefore, we conclude that the fuzzy model could be a useful tool to assist the general practitioner in the selection of patients for MPS.
Resumo:
In the past thirty years, a series of plans have been developed by successive Brazilian governments in a continuing effort to maximize the nation's resources for economic and social growth. This planning history has been quantitatively rich but qualitatively poor. The disjunction has stimulated Professor Mello e Souza to address himself to the problem of national planning and to offer some criticisms of Brazilian planning experience. Though political instability has obviously been a factor promoting discontinuity, his criticisms are aimed at the attitudes and strategic concepts which have sought to link planning to national goals and administration. He criticizes the fascination with techniques and plans to the exclusion of proper diagnosis of the socio-political reality, developing instruments to coordinate and carry out objectives, and creating an administrative structure centralized enough to make national decisions and decentralized enough to perform on the basis of those decisions. Thus, fixed, quantified objectives abound while the problem of functioning mechanisms for the coordinated, rational use of resources has been left unattended. Although his interest and criticism are focused on the process and experience of national planning, he recognized variation in the level and results of Brazilian planning. National plans have failed due to faulty conception of the function of planning. Sectorial plans, save in the sector of the petroleum industry under government responsibility, ha e not succeeded in overcoming the problems of formulation and execution thereby repeating old technical errors. Planning for the private sector has a somewhat brighter history due to the use of Grupos Executivos which has enabled the planning process to transcend the formalism and tradition-bound attitudes of the regular bureaucracy. Regional planning offers two relatively successful experiences, Sudene and the strategy of the regionally oriented autarchy. Thus, planning history in Brazil is not entirely black but a certain shade of grey. The major part of the article, however, is devoted to a descriptive analysis of the national planning experience. The plans included in this analysis are: The Works and Equipment Plan (POE); The Health, Food, Transportation and Energy Plan (Salte); The Program of Goals; The Trienal Plan of Economic and Social Development; and the Plan of Governmental Economic Action (Paeg). Using these five plans for his historical experience the author sets out a series of errors of formulation and execution by which he analyzes that experience. With respect to formulation, he speaks of a lack of elaboration of programs and projects, of coordination among diverse goals, and of provision of qualified staff and techniques. He mentions the absence of the definition of resources necessary to the financing of the plan and the inadequate quantification of sectorial and national goals due to the lack of reliable statistical information. Finally, he notes the failure to coordinate the annual budget with the multi-year plans. He sees the problems of execution as beginning in the absence of coordination between the various sectors of the public administration, the failure to develop an operative system of decentralization, the absence of any system of financial and fiscal control over execution, the difficulties imposed by the system of public accounting, and the absence of an adequate program of allocation for the liberation of resources. He ends by pointing to the failure to develop and use an integrated system of political economic tools in a mode compatible with the objective of the plans. The body of the article analyzes national planning experience in Brazil using these lists of errors as rough model of criticism. Several conclusions emerge from this analysis with regard to planning in Brazil and in developing countries, in general. Plans have generally been of little avail in Brazil because of the lack of a continuous, bureaucratized (in the Weberian sense) planning organization set in an instrumentally suitable administrative structure and based on thorough diagnoses of socio-economic conditions and problems. Plans have become the justification for planning. Planning has come to be conceived as a rational method of orienting the process of decisions through the establishment of a precise and quantified relation between means and ends. But this conception has led to a planning history rimmed with frustration, and failure, because of its rigidity in the face of flexible and changing reality. Rather, he suggests a conception of planning which understands it "as a rational process of formulating decisions about the policy, economy, and society whose only demand is that of managing the instrumentarium in a harmonious and integrated form in order to reach explicit, but not quantified ends". He calls this "planning without plans": the establishment of broad-scale tendencies through diagnosis whose implementation is carried out through an adjustable, coherent instrumentarium of political-economic tools. Administration according to a plan of multiple, integrated goals is a sound procedure if the nation's administrative machinery contains the technical development needed to control the multiple variables linked to any situation of socio-economic change. Brazil does not possess this level of refinement and any strategy of planning relevant to its problems must recognize this. The reforms which have been attempted fail to make this recognition as is true of the conception of planning informing the Brazilian experience. Therefore, unworkable plans, ill-diagnosed with little or no supportive instrumentarium or flexibility have been Brazil's legacy. This legacy seems likely to continue until the conception of planning comes to live in the reality of Brazil.
Resumo:
A recent and comprehensive review of the use of race and ethnicity in research that address health disparities in epidemiology and public health is provided. First it is described the theoretical basis upon which race and ethnicity differ drawing from previous work in anthropology, social science and public health. Second, it is presented a review of 280 articles published in high impacts factor journals in regards to public health and epidemiology from 2009-2011. An analytical grid enabled the examination of conceptual, theoretical and methodological questions related to the use of both concepts. The majority of articles reviewed were grounded in a theoretical framework and provided interpretations from various models. However, key problems identified include a) a failure from researchers to differentiate between the concepts of race and ethnicity; b) an inappropriate use of racial categories to ascribe ethnicity; c) a lack of transparency in the methods used to assess both concepts; and d) failure to address limits associated with the construction of racial or ethnic taxonomies and their use. In conclusion, future studies examining health disparities should clearly establish the distinction between race and ethnicity, develop theoretically driven research and address specific questions about the relationships between race, ethnicity and health. One argue that one way to think about ethnicity, race and health is to dichotomize research into two sets of questions about the relationship between human diversity and health.
Resumo:
Youngsters are increasingly using 3,4 methylenedioxymethamphetamine, known as ecstasy, because it is wrongly believed that it does not induce harm. However, there are many reports of adverse effects, including acute intoxication, abuse potential, and possible neurotoxic effects. Therefore, health care providers need to promptly recognize the symptoms of systemic intoxication in order to initiate early treatment. The drug is used by the oral route for long hours during crowded dance parties. Acutely, ecstasy increases the release of serotonin and decreases its reuptake, leading to hypertension, hyperthermia, trismus, and vomiting. There is debate on whether recreational doses of ecstasy cause permanent damage to human serotonergic neurons. Ecstasy users showed a high risk of developing psychopathological disturbances. The prolonged use of ecstasy might induce dependence, characterized by tolerance and hangover. Acute ecstasy intoxication needs emergency-type treatment to avoid the dose-dependent increase in adverse reactions and in severity of complications. There are no specific antidotes to be used during acute intoxication. Supportive measures and medical treatment for each one of the complications should be implemented, keeping in mind that symptoms originate mainly from the central nervous system and the cardiovascular system.
Resumo:
In order to find out the best way to supply phosphorus to coffee plants when growing in "terra roxa misturada", a red soil with a high fixing capacity, tagged superphosphate was applied by the following procedures: (1) topdressed in a circular strip around the trees; (2) placed in the bottom of a circular furrow 15 cm deep; (3) placed in a semicircular furrow also 15 cm deep; (4) sprayed directly to the leaves. In each case 150 gms. of ordinary superphosphate tagged with H3 P32 O4 to give 5 X 10(9) c.p.m. were given to the two and half year old coffee plants. It was found that for the several treatments of the total phosphorus in the leaves the following values, on a per cent basis, came from the applied superphosphates: (1) topdressed 10.2 per cent, (2) circular furrow 2.4 per cent, (3) semicircular furrow 1.7 per cent, (4) sprayed 38.0 per cent; one can see, then, that methods (2) and (3) commonly used by the coffee planters are a very inefficient way to supply phosphorus in this type of soil. The remarkable foliar absorption was checked twice: a water culture experiment was carried out, the radiophosphorus being supplied by brushing it in the upper and lower surfaces of a given leaf; radioactivity was detected all over the plant as a result both of absorption and translocation; on the other hand, leaves collected from the sprayed trees were radioautographed; the radioautographs showed the pattern of distribution of the P32 which indicates true absorption rather than a surface contamination. In another locality, an experiment was caried out with 8 year old plants growing in "arenito de Bauru" which is a sandy soil with much less phosphorus fixing capacity. In this experiment the aim was to compare absorption of tagged superphosphate by trees growin under mulch against plants not receiving this treatment, The uptake of phosphorus was the same for both sets of plants. In both field experiments soil samples down to 15 cm in the profile were collected and its 0.2NHC1 soluble phosphorus was counted; rather significant values were observed mainly in the upper 5 cm layers.
Resumo:
Morbidity in schistosomiasis mansoni occurs primaryly as a result of the complications of hepatic fibrosis. Yet, the pathogenesis of schistosomal hepatic fibrosis is poorly understood. The fact that hepatic egg granuloma is the hallmark of this infection suggests a potential role for granulomatous inflamation in hepatic fibrogenesis. Our studies in a murine schistosomiasis model indicate that hepatic granuloma cells secrete a variety of fibrogenic cytokines that may initiate the scarring process. Among these cytokines, we identified a novel protein that we designated fibroplast stimulating factor-1 (FsF-1). FsF-1 is a lymphokine that can stimulate fibroplast growth and matrix synthesis. A notable feature of hepatic fibrosis in this model is that production of FsF-1 and other granuloma-derived fibrogenic cytokines is down-regulated in chronic infection, an event that may be under immunological control. The spontaneous reduction of FsF-1 secretion presumably accounts for reduced scar formation late in infection of mice. In the context of relevant clinical studies, our findings engender the hypothesis that Symmer's fibrosis may develop in a small suppopulation of individuals as a result of immunogenetically-determined dysregulation of fibrogenic cytokine production.
Resumo:
Molecular cloning of components of protective antigenic preparations have suggested that related parasite fatty acid binding proteins could form the basis of the well documented protective, immune cross reactivity between the parasitic trematode worms Fasciola hepatica and Schistosoma mansoni. We have now confirmed the cross protective potential of parasite fatty acid binding proteins and suggest that it may be possible to produce a single vaccine that would be effective against at least two parasites, F. hepatica and S. mansoni of veterinary and human importance respectively.
Resumo:
Ribotyping has been widely used to characterise the seventh pandemic clone including South American and O139 variants which appeared in 1991 and 1992 respectively. To reveal the molecular basis of ribotype variation we analysed the rrn operons and their flanking regions. All but one variation detected by BglI, the most discriminatory enzyme, was found to be due to changes within the rrn operons, resulting from recombination between operons. The recombinants are detected because of the presence of a BglI site in the 16S gene in three of the nine rrn operons and/or changes of intergenic spacer types of which four variants were identified. As the frequency of rrn recombination is high, ribotyping becomes a less useful tool for evolutionary studies and long term monitoring of the pathogenic clones of Vibrio cholerae as variation could undergo precise reversion by the same recombination event.
Resumo:
A new approach to dengue vector surveillance based on permanent egg-collection using a modified ovitrap and Bacillus thuringiensis israelensis(Bti) was evaluated in different urban landscapes in Recife, Northeast Brazil. From April 2004 to April 2005, 13 egg-collection cycles of four weeks were carried out. Geo-referenced ovitraps containing grass infusion, Bti and three paddles were placed at fixed sampling stations distributed over five selected sites. Continuous egg-collections yielded more than four million eggs laid into 464 sentinel-ovitraps over one year. The overall positive ovitrap index was 98.5% (over 5,616 trap observations). The egg density index ranged from 100 to 2,500 eggs per trap-cycle, indicating a wide spread and high density of Aedes aegypti (Diptera: Culicidae) breeding populations in all sites. Fluctuations in population density over time were observed, particularly a marked increase from January on, or later, according to site. Massive egg-collection carried out at one of the sites prevented such a population outbreak. At intra-site level, egg counts made it possible to identify spots where the vector population is consistently concentrated over the time, pinpointing areas that should be considered high priority for control activities. The results indicate that these could be promising strategies for detecting and preventing Ae. aegypti population outbreaks.
Resumo:
The objective of this study was to detect and identify hepatitis E virus (HEV) strains in liver and bile samples from slaughtered pigs in the state of Paraná, Brazil. Liver and bile samples were collected from 118 asymptomatic adult pigs at a slaughterhouse in a major Brazilian pork production area. The samples were assayed using a nested reverse transcription-polymerase chain reaction protocol with primer sets targeting open reading frames (ORF)1 and 2 of the HEV genome. HEV RNA was detected in two (1.7%) liver samples and one (0.84%) bile sample using both primers sets. The HEV strains were classified as genotype 3b on the basis of their nucleotide sequences. These data suggest that healthy pigs may be a source of HEV infection for consumers of pig liver and slaughterhouse workers in Brazil.