Divergência genética em procedências e progênies de Araucaria angustifolia Bert. O. Ktze a partir de caracteres fenotípicos.

Resumo

Imaginary Phases in Two-Level Model with Spontaneous Decay

We study a two-level model coupled to the electromagnetic vacuum and to an external classic electric field with fixed frequency. The amplitude of the external electric field is supposed to vary very slow in time. Garrison and Wright [{\it Phys. Lett.} {\bf A128} (1988) 177] used the non-hermitian Hamiltonian approach to study the adiabatic limit of this model and obtained that the probability of this two-level system to be in its upper level has an imaginary geometric phase. Using the master equation for describing the time evolution of the two-level system we obtain that the imaginary phase due to dissipative effects is time dependent, in opposition to Garrison and Wright result. The present results show that the non-hermitian hamiltonian method should not be used to discuss the nature of the imaginary phases in open systems.Comment: 11 pages, new version, to appear in J. Phys.

Modeling dengue immune responses mediated by antibodies: A qualitative study

Dengue fever is a viral mosquito-borne infection and a major international public health concern. With 2.5 billion people at risk of acquiring the infection around the world, disease severity is influenced by the immunological status of the individual, seronegative or seropositive, prior to natural infection. Caused by four antigenically related but distinct serotypes, DENV-1 to DENV-4, infection by one serotype confers life-long immunity to that serotype and a period of temporary cross-immunity (TCI) to other serotypes. The clinical response on exposure to a second serotype is complex with the so-called antibody-dependent enhancement (ADE) process, a disease augmentation phenomenon when pre-existing antibodies to previous dengue infection do not neutralize but rather enhance the new infection, used to explain the etiology of severe disease. In this paper, we present a minimalistic mathematical model framework developed to describe qualitatively the dengue immunological response mediated by antibodies. Three models are analyzed and compared: (i) primary dengue infection, (ii) secondary dengue infection with the same (homologous) dengue virus and (iii) secondary dengue infection with a different (heterologous) dengue virus. We explore the features of viral replication, antibody production and infection clearance over time. The model is developed based on body cells and free virus interactions resulting in infected cells activating antibody production. Our mathematical results are qualitatively similar to the ones described in the empiric immunology literature, providing insights into the immunopathogenesis of severe disease. Results presented here are of use for future research directions to evaluate the impact of dengue vaccines.A.S, H.F., and E.S. E.S. has received funded from the Indonesian RistekBrin Grant No. 122M/IT1.C02/TA.00/2021, 2021 (previously RistekDikti 2018-2021). M.A. received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 792494

Revisiting Natural Radiation in Itacaré and Guarapari Beaches

Human beings are constantly exposed to several types of natural radiation. This paper aims to study the total external dose from northwestern Brazilian beach sands. The samples were collected at Prainha in Itacaré, Bahia, and Praia de AreiaPreta in Guarapari, Espírito Santo. Gamma spectrometry is a very useful technique to estimate the effective dose due to naturally occurring radionuclides, such as 40K and daughters of 238U and 232Th. In order to confirm the high activity present in these two regions, the effective dose due to each natural radionuclide was determined. Moreover, the Energy-Dispersive X-Ray Spectroscopy (EDS) microanalysis was used to characterize the soil composition and the minerals responsible for the high activity. In addition, the sand samples were separated in to magnetic and non-magnetic fractions in order to identify the contribution from each portion of the activity. Finally, the radionuclides and their dispersion in those places are consistent with previous studies, indicating effective doses above the world average that is between 0.3 mSv/year and 1.0 mSv/year

Modeling Dengue Immune Responses Mediated by Antibodies: Insights on the Biological Parameters to Describe Dengue Infections

Dengue fever is a viral mosquito-borne disease, a significant global health concern, with more than one third of the world population at risk of acquiring the disease. Caused by 4 antigenically distinct but related virus serotypes, named DENV-1, DENV-2, DENV-3, and DENV-4, infection by one serotype confers lifelong immunity to that serotype and a short period of temporary cross immunity to other related serotypes. Severe dengue is epidemiologically associated with a secondary infection caused by a heterologous serotype via the so-called antibody-dependent enhancement (ADE), an immunological process enhancing a new infection. Within-host dengue modeling is restricted to a small number of studies so far. With many open questions, the understanding of immunopathogenesis of severe disease during recurrent infections is important to evaluate the impact of newly licensed vaccines. In this paper, we revisit the modeling framework proposed by Sebayang et al. and perform a detailed sensitivity analysis of the well-known biological parameters and its possible combinations to understand the existing data sets. Using numerical simulations, we investigate features of viral replication, antibody production, and infection clearance over time for three possible scenarios: primary infection, secondary infection caused by homologous serotype, and secondary infection caused by heterologous serotype. Besides, describing well the infection dynamics as reported in the immunology literature, our results provide information on parameter combinations to best describe the differences on the immunological dynamics of secondary infections with homologous and heterologous viruses. The results presented here will be used as baseline to investigate a more complex within-host dengue model.Marie Skłodowska-Curie grant agreement No 79249

Braidings of Tensor Spaces

Let $V$ be a braided vector space, that is, a vector space together with a solution $\hat{R}\in {\text{End}}(V\otimes V)$ of the Yang--Baxter equation. Denote $T(V):=\bigoplus_k V^{\otimes k}$. We associate to $\hat{R}$ a solution $T(\hat{R})\in {\text{End}}(T(V)\otimes T(V))$ of the Yang--Baxter equation on the tensor space $T(V)$. The correspondence $\hat{R}\rightsquigarrow T(\hat{R})$ is functorial with respect to $V$.Comment: 10 pages, no figure

Dados climatológicos: Estação de Quixadá, 2002.

bitstream/CNPAT/7899/1/doc77.pd

Semiclassical Propagation of Wavepackets with Real and Complex Trajectories

We consider a semiclassical approximation for the time evolution of an originally gaussian wave packet in terms of complex trajectories. We also derive additional approximations replacing the complex trajectories by real ones. These yield three different semiclassical formulae involving different real trajectories. One of these formulae is Heller's thawed gaussian approximation. The other approximations are non-gaussian and may involve several trajectories determined by mixed initial-final conditions. These different formulae are tested for the cases of scattering by a hard wall, scattering by an attractive gaussian potential, and bound motion in a quartic oscillator. The formula with complex trajectories gives good results in all cases. The non-gaussian approximations with real trajectories work well in some cases, whereas the thawed gaussian works only in very simple situations.Comment: revised text, 24 pages, 6 figure

Thermal Analysis of a Finned Thermosyphon for Heat Exchanger Applications

A thermosyphon is a gravity-assisted heat pipe used to improve the heat transfer in several applications. In this paper, a thermal analysis of a finned thermosyphon for heat exchanger applications was experimentally researched. The thermosyphon was manufactured from a copper tube the external diameter of 9.45 mm, the inner diameter of 7.75 mm, and a total length of 200 mm. The working fluid used was water with a filling ratio of 40% of the evaporator volume. The condenser was cooled by air forced convection, the adiabatic section was insulated with fiberglass and the evaporator was heated by an electrical resistor. Experimental tests were performed to a heat load from 5 up to 50W at vertical position (evaporator above condenser). As a result of the research, the thermosyphon operated satisfactorily to the tested position. Also, the finned thermosyphon obtained better thermal performance than the un-finned condenser, proving the effectiveness of the fin application