25 resultados para Strict Convexity
Resumo:
While many developed countries have invested heavily in research on plant invasions over the last 50 years, the immense region of Latin America has made little progress. Recognising this, a group of scientists working on plant invasions in Latin America met in Chile in late 2010 to develop a research agenda for the region based on lessons learned elsewhere. Our three main findings are as follows. (1) Globalisation is inevitable, but the resultant plant introductions can be slowed or prevented by effective quarantine and early intervention. Development of spatially explicit inventories, research on the invasion process and weed risk assessments can help prioritise and streamline action. (2) Eradication has limited application for plants and control is expensive and requires strict prioritisation and careful planning and evaluation. (3) Accepting the concept of novel ecosystems, new combinations of native and introduced species that no longer depend on human intervention, may help optimise invasive species management. Our vision of novel ecosystem management is through actions that: (a) maintain as much native biodiversity and ecosystem functionality as possible, (b) minimise management intervention to invasives with known impact, and (c) maximise the area of intervention. We propose the creation of a Latin American Invasive Plants Network to help focus the new research agenda for member countries. The network would coordinate research and training and establish funding priorities, develop and strengthen tools to share knowledge, and raise awareness at the community, governmental and intergovernmental levels about the social, economic and environmental costs of plant invasions.
Resumo:
Context. The angular diameter distances toward galaxy clusters can be determined with measurements of Sunyaev-Zel'dovich effect and X-ray surface brightness combined with the validity of the distance-duality relation, D-L(z)(1 + z)(2)/D-A(z) = 1, where D-L(z) and D-A(z) are, respectively, the luminosity and angular diameter distances. This combination enables us to probe galaxy cluster physics or even to test the validity of the distance-duality relation itself. Aims. We explore these possibilities based on two different, but complementary approaches. Firstly, in order to constrain the possible galaxy cluster morphologies, the validity of the distance-duality relation (DD relation) is assumed in the Lambda CDM framework (WMAP7). Secondly, by adopting a cosmological-model-independent test, we directly confront the angular diameters from galaxy clusters with two supernovae Ia (SNe Ia) subsamples (carefully chosen to coincide with the cluster positions). The influence of the different SNe Ia light-curve fitters in the previous analysis are also discussed. Methods. We assumed that eta is a function of the redshift parametrized by two different relations: eta(z) = 1 +eta(0)z, and eta(z) = 1 + eta(0)z/(1 + z), where eta(0) is a constant parameter quantifying the possible departure from the strict validity of the DD relation. In order to determine the probability density function (PDF) of eta(0), we considered the angular diameter distances from galaxy clusters recently studied by two different groups by assuming elliptical and spherical isothermal beta models and spherical non-isothermal beta model. The strict validity of the DD relation will occur only if the maximum value of eta(0) PDF is centered on eta(0) = 0. Results. For both approaches we find that the elliptical beta model agrees with the distance-duality relation, whereas the non-isothermal spherical description is, in the best scenario, only marginally compatible. We find that the two-light curve fitters (SALT2 and MLCS2K2) present a statistically significant conflict, and a joint analysis involving the different approaches suggests that clusters are endowed with an elliptical geometry as previously assumed. Conclusions. The statistical analysis presented here provides new evidence that the true geometry of clusters is elliptical. In principle, it is remarkable that a local property such as the geometry of galaxy clusters might be constrained by a global argument like the one provided by the cosmological distance-duality relation.
Resumo:
Active pharmaceutical ingredients have very strict quality requirements; minor changes in the physical and chemical properties of pharmaceuticals can adversely affect the dissolution rate and therefore the bioavailability of a given drug. Accordingly, the aim of the present study was to investigate the effect of spray drying on the physical and in vitro dissolution properties of four different active pharmaceutical ingredients, namely carbamazepine, indomethacin, piroxicam, and nifedipine. Each drug was dispersed in a solution of ethanol and water (70:30) and subjected to single-step spray drying using similar operational conditions. A complete characterization of the spray-dried drugs was performed via differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), particle size distribution analysis, solubility analysis, and an in vitro dissolution study. The results from the thermal analysis and X-ray diffraction showed that, except for carbamazepine, no chemical modifications occurred as a result of spray drying. Moreover, the particle size distribution of all the spray-dried drugs significantly decreased. In addition, SEM images showed that most of the particles had an irregular shape. There was no significant improvement in the solubility of the spray-dried drugs compared with the unprocessed compounds; however, in general, the dissolution rates of the spray-dried drugs showed a remarkable improvement over their non-spray-dried counterparts. Therefore, the results from this study demonstrate that a single spray-drying step may lead to changes in the physical properties and dissolution characteristics of drugs and thus improve their therapeutic action.
Resumo:
Nanosized rare earth phosphovanadate phosphors (Y(P,V)O-4:Eu3+) have been prepared by applying the organic-inorganic polymeric precursors methodology. Luminescent powders with tetragonal structure and different vanadate concentrations (0%, 1%, 5%, 10%, 20%, 50%, and 100%, with regard to the phosphate content) were then obtained for evaluation of their structural and spectroscopic properties. The solids were characterized by scanning electron microscopy, X-ray diffractometry, vibrational spectroscopy (Raman and infrared), and electronic spectroscopy (emission, excitation, luminescence lifetimes, chromaticity, quantum efficiencies, and Judd-Ofelt intensity parameters). The solids exhibited very intense D-5(0) -> F-7(J) Eu3+ transitions, and it was possible to control the luminescent characteristics, such as excitation maximum, lifetime and emission colour, through the vanadium(V) concentration. The observed luminescent properties correlated to the characteristics of the chemical environments around the Eu3+ ions with respect to the composition of the phosphovanadates. The Eu3+ luminescence spectroscopy results indicated that the presence of larger vanadium(V) amounts in the phosphate host lattice led to more covalent and polarizable chemical environments. So, besides allowing for control of the luminescent properties of the solids, the variation in the vanadate concentration in the obtained YPO4:Eu3+ phosphors enabled the establishment of a strict correlation between the observable spectroscopic features and the chemical characteristics of the powders.
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Introduction: This retrospective cephalometric study analyzed the influence of intentional ankylosis of deciduous canines in patients with Class III malocclusion and anterior crossbite, in the deciduous and early mixed dentition stages, treated by orthopedic maxillary expansion followed by maxillary protraction. Methods: Lateral cephalograms of 40 patients were used, divided in 2 groups paired for age and gender. The Ankylosis Group was composed of 20 patients (10 boys and 10 girls) treated with induced ankylosis and presenting initial and final mean ages of 7 years 4 months and 8 years 3 months, respectively, with a mean period of maxillary protraction of 11 months. The Control Group comprised 20 patients (10 boys and 10 girls) treated without induced ankylosis, with initial and final mean ages of 7 years 8 months and 8 years 7 months, respectively, with a mean period of maxillary protraction of 11 months. Two-way analysis of variance and covariance analysis were applied to compare the initial and final cephalometric variables and the treatment changes between groups. Results: According to the results, the variables evidencing the significant treatment changes between groups confirmed that the intentional ankylosis enhanced the sagittal response of the apical bases (Pg-NPerp) and increased the facial convexity angles (NAP and ANB). Conclusions: The protocol involving intentional ankylosis of deciduous canines enhanced the sagittal response of the apical bases.
Effect of incorporation of amaranth on the physical properties and nutritional value of cheese bread
Resumo:
At the present celiac disease has no known cure, and its only treatment is a strict lifelong adherence to a gluten-free diet. Cheese bread is a traditional Brazilian product and a safe option for celiacs. However, like other gluten-free breads, it has inherent low levels of fibers and minerals. The objective of this study was to evaluate the effect of incorporation of whole amaranth flour on the physical properties and nutritional value of cheese bread. Amaranth flour was incorporated at 10, 15, and 20% proportions in different formulations. The increasing amaranth levels darkened the product, reduced specific volume, and increased compression force. Ten percent amaranth-content cheese breads exhibited slight differences in physical properties compared with the controls. These results demonstrated the possibility of incorporating 10% of whole amaranth flour in the formulation of cheese bread resulting in a product with higher dietary fiber and iron contents and the same level of acceptance as that of the conventional formulation. The aim of this approach is to increase the availability of gluten-free bakery products with added nutritional value contributing to increase the variety of the diet of celiac patients.
Resumo:
O objetivo deste estudo é analisar os procedimentos manejados na fiscalização de professores primários, por meio do estudo a respeito do serviço de inspeção da instrução na Corte Imperial, a partir de sua institucionalização com base no Regulamento da Instrução Primária e Secundária da Corte em 1854. Na pesquisa procurou-se discutir como a visibilidade dada à escola e aos seus atores, via inspeção, permitiram inseri-los em um esquema disciplinar, cujos efeitos encontram-se articulados e justificados em nome de um projeto de ordenação e civilização da capital do Império brasileiro.
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Abstract Background The criteria for organ sharing has developed a system that prioritizes liver transplantation (LT) for patients with hepatocellular carcinoma (HCC) who have the highest risk of wait-list mortality. In some countries this model allows patients only within the Milan Criteria (MC, defined by the presence of a single nodule up to 5 cm, up to three nodules none larger than 3 cm, with no evidence of extrahepatic spread or macrovascular invasion) to be evaluated for liver transplantation. This police implies that some patients with HCC slightly more advanced than those allowed by the current strict selection criteria will be excluded, even though LT for these patients might be associated with acceptable long-term outcomes. Methods We propose a mathematical approach to study the consequences of relaxing the MC for patients with HCC that do not comply with the current rules for inclusion in the transplantation candidate list. We consider overall 5-years survival rates compatible with the ones reported in the literature. We calculate the best strategy that would minimize the total mortality of the affected population, that is, the total number of people in both groups of HCC patients that die after 5 years of the implementation of the strategy, either by post-transplantation death or by death due to the basic HCC. We illustrate the above analysis with a simulation of a theoretical population of 1,500 HCC patients with tumor size exponentially. The parameter λ obtained from the literature was equal to 0.3. As the total number of patients in these real samples was 327 patients, this implied in an average size of 3.3 cm and a 95% confidence interval of [2.9; 3.7]. The total number of available livers to be grafted was assumed to be 500. Results With 1500 patients in the waiting list and 500 grafts available we simulated the total number of deaths in both transplanted and non-transplanted HCC patients after 5 years as a function of the tumor size of transplanted patients. The total number of deaths drops down monotonically with tumor size, reaching a minimum at size equals to 7 cm, increasing from thereafter. With tumor size equals to 10 cm the total mortality is equal to the 5 cm threshold of the Milan criteria. Conclusion We concluded that it is possible to include patients with tumor size up to 10 cm without increasing the total mortality of this population.
Resumo:
O Mycobacterium bovis incluído no complexo Mycobacterium tuberculosis pode infectar várias espécies de animais domésticos e silvestres. Embora acometa principalmente animais da espécie bovina também pode infectar outros mamíferos e inclusive os seres humanos, nos quais determina um quadro clínico indistinguível do causado pelo M. tuberculosis. Em diversos países desenvolvidos, devido à aplicação de rigorosas medidas de controle e consequente redução da prevalência da tuberculose bovina, bem como de infecções em outras espécies de animais pelo M. bovis houve em decréscimo dos níveis de ocorrência desta patologia e o tema passou a ser considerado de menor importância. No entanto, nos países em desenvolvimento, a infecção por M. bovis ainda representa um importante risco para a saúde pública, pois tem sido observada nos animais domésticos, silvestres e em seres humanos. O presente trabalho analisa a importância da infecção pelo Mycobacterium bovis em termos de saúde pública.
Resumo:
In this work, we reported some results about the stochastic quantization of the spherical model. We started by reviewing some basic aspects of this method with emphasis in the connection between the Langevin equation and the supersymmetric quantum mechanics, aiming at the application of the corresponding connection to the spherical model. An intuitive idea is that when applied to the spherical model this gives rise to a supersymmetric version that is identified with one studied in Phys. Rev. E 85, 061109, (2012). Before investigating in detail this aspect, we studied the stochastic quantization of the mean spherical model that is simpler to implement than the one with the strict constraint. We also highlight some points concerning more traditional methods discussed in the literature like canonical and path integral quantization. To produce a supersymmetric version, grounded in the Nicolai map, we investigated the stochastic quantization of the strict spherical model. We showed in fact that the result of this process is an off-shell supersymmetric extension of the quantum spherical model (with the precise supersymmetric constraint structure). That analysis establishes a connection between the classical model and its supersymmetric quantum counterpart. The supersymmetric version in this way constructed is a more natural one and gives further support and motivations to investigate similar connections in other models of the literature.