358 research outputs found
Systematics of species of the genus Akodon (Rodentia: Sigmodontinae) in southeastern Brazil and implications for the biogeography of the Campos de Altitude
http://deepblue.lib.umich.edu/bitstream/2027.42/111041/1/MP197.pd
Chaotic behaviour of seismic mechanisms: observation and models
Today, it is impractical work modelling the dynamics of failure, given the high complexity of the systems involved. As soon, it is important to identify models, as simples as possible, with qualitatively similar to the failures. The first model introducing is it the mechanical block-spring model, given by Burrigde-Knopoff [1]. In this work the subject was treated by experimental means. For that purpose it was developed and designed a mechanical system similar it that used in the numerical modulations, the so called earthquake machine (shown in Figure 1). We have equipped the springs of the machine with a set of force sensors connected to a data acquisition system (DAQ), linked in turn to a computer. The data recorded in the mechanical prototype consists of temporal series of tensions measured by the sensors that correspond to the sequence of tension accumulation and drop taking place in the springs.
Data processing followed two distinct methodologies. The first treated the data according to the techniques used in seismology with field measurements. In the second methodology, we tried to use the series recorded in the context of chaos theories to investigate the behaviour of prototype
Gestão ambiental nas residências de estudantes do Instituto Politécnico de Bragança
A preocupação com o desenvolvimento sustentável junto com o aprimoramento de ações de gestão
ambiental vem ganhando um espaço crescente nas Instituições de Ensino Superior. Isto tem se
revelado a partir da abordagem educacional passada aos estudantes das Instituições de Ensino
Superior sobre desenvolvimento sustentável a partir dos exemplos práticos incorporados nas
operações dos campus. O objetivo desse estudo foi analisar a estrutura, o comportamento e os
processos que são realizados nos seis dormitórios acadêmicos do instituto politécnico de Bragança,
que são eles o dormitório Verde, Castanho, Gulbenkian, Domus Feminina, Domus Masculina e
Domus Visitante, quanto ao impacto ambiental gerado por cada uma. Para tal análise essa dissertação
aborda temas como desenvolvimento sustentável, environmentally responsible behaviour, green
buildings e as NP EN ISO 14001:2015 e NP EN ISO 19011:2012. Esses temas serviram como base
para a realização da metodologia, que se constituiu a partir de realização de auditorias ambientais em
cada uma das residências, com visita as instalações e registro fotográfico. A partir dos dados coletados
nessas auditorias, foi feito um relatório com plano de ação constando as mudanças cabíveis para
melhor gestão ambiental desses locais. Vale ressaltar que todos os documentos como a lista de
verificação usada na auditoria e o relatório final foram de própria elaboração. Para analisar a
perspectiva vivido pelos moradores, foi aplicado um inquérito com questões de diversas áreas, tais
como consumo de água, energia, gás, conforto térmico, hábitos de consumo e mobilidade. Essas
questões foram elaboradas para entender melhor as carências e pontos de melhoria tanto de educação
ambiental como de adequação das instalações. Para análise dos resultados obtidos a partir desses
inquéritos, foi utilizado o software IBM SPSS.info:eu-repo/semantics/publishedVersio
Systematics of species of the genus Akodon (Rodentia: Sigmodontinae) in southeastern Brazil and implications for the biogeography of the Campos de Altitude.
Faunal inventories of the highest peaks of the Atlantic forests of South America, in the Caparaó and Itatiaia mountain ranges in Southeastern Brazil, have revealed a new community of small mammals. The species making up this community appear to be restricted to the highest altitudinal zones and are found in close association with scattered montane grasslands (campos de altitude). Their phylogenetic relationships can provide insights into speciation in mountaintop communities of the Atlantic forest. In this paper we review the taxonomic identity and systematic relationships of Akodon mystax, a high- altitude endemic described from Caparaó. We demonstrate that populations from Itatiaia previously assigned to mystax are morphologically, cytogenetically and genetically distinct from that species and appear to represent a northern isolate of Akodon paranaensis, and that Akodon mystax is closely related to Akodon lindberghi from the Central Brazilian grasslands. Phylogenetic relationships among these populations demonstrate that differentiation of the mountaintop endemics of Caparaó and Itatiaia is not solely attributable the isolation of campos de altitude from southern grasslands of Brazil and Uruguay as grasslands retreated southward, phylogenetic analyses of some groups suggest connections between the campos de altitude and Central Brazil."http://deepblue.lib.umich.edu/bitstream/2027.42/102734/1/MP197.pd
Commissioning of an ultra-high dose rate pulsed electron beam medical LINAC for FLASH RT preclinical animal experiments and future clinical human protocols.
To present the acceptance and the commissioning, to define the reference dose, and to prepare the reference data for a quality assessment (QA) program of an ultra-high dose rate (UHDR) electron device in order to validate it for preclinical animal FLASH radiotherapy (FLASH RT) experiments and for FLASH RT clinical human protocols.
The Mobetron <sup>®</sup> device was evaluated with electron beams of 9 MeV in conventional (CONV) mode and of 6 and 9 MeV in UHDR mode (nominal energy). The acceptance was performed according to the acceptance protocol of the company. The commissioning consisted of determining the short- and long-term stability of the device, the measurement of percent depth dose curves (PDDs) and profiles at two different positions (with two different dose per pulse regimen) and for different collimator sizes, and the evaluation of the variability of these parameters when changing the pulse width and pulse repetition frequency. Measurements were performed using a redundant and validated dosimetric strategy with alanine and radiochromic films, as well as Advanced Markus ionization chamber for some measurements.
The acceptance tests were all within the tolerances of the company's acceptance protocol. The linearity with pulse width was within 1.5% in all cases. The pulse repetition frequency did not affect the delivered dose more than 2% in all cases but 90 Hz, for which the larger difference was 3.8%. The reference dosimetry showed a good agreement within the alanine and films with variations of 2.2% or less. The short-term (resp. long-term) stability was less than 1.0% (resp. 1.8%) and was the same in both CONV and UHDR modes. PDDs, profiles, and reference dosimetry were measured at two positions, providing data for two specific dose rates (about 9 Gy/pulse and 3 Gy/pulse). Maximal beam size was 4 and 6 cm at 90% isodose in the two positions tested. There was no difference between CONV and UHDR mode in the beam characteristics tested.
The device is commissioned for FLASH RT preclinical biological experiments as well as FLASH RT clinical human protocols
Simple heuristics for the assembly line worker assignment and balancing problem
We propose simple heuristics for the assembly line worker assignment and
balancing problem. This problem typically occurs in assembly lines in sheltered
work centers for the disabled. Different from the classical simple assembly
line balancing problem, the task execution times vary according to the assigned
worker. We develop a constructive heuristic framework based on task and worker
priority rules defining the order in which the tasks and workers should be
assigned to the workstations. We present a number of such rules and compare
their performance across three possible uses: as a stand-alone method, as an
initial solution generator for meta-heuristics, and as a decoder for a hybrid
genetic algorithm. Our results show that the heuristics are fast, they obtain
good results as a stand-alone method and are efficient when used as a initial
solution generator or as a solution decoder within more elaborate approaches.Comment: 18 pages, 1 figur
Critical Collapse of Cylindrically Symmetric Scalar Field in Four-Dimensional Einstein's Theory of Gravity
Four-dimensional cylindrically symmetric spacetimes with homothetic
self-similarity are studied in the context of Einstein's Theory of Gravity, and
a class of exact solutions to the Einstein-massless scalar field equations is
found. Their local and global properties are investigated and found that they
represent gravitational collapse of a massless scalar field. In some cases the
collapse forms black holes with cylindrical symmetry, while in the other cases
it does not. The linear perturbations of these solutions are also studied and
given in closed form. From the spectra of the unstable eigen-modes, it is found
that there exists one solution that has precisely one unstable mode, which may
represent a critical solution, sitting on a boundary that separates two
different basins of attraction in the phase space.Comment: Some typos are corrected. The final version to appear in Phys. Rev.
Avaliação Da Produção De Látex Em Mangabeiras Do Cerrado Goiano
The mangabeira latex, plant native from Cerrado, shows biotechnological potential for the development of new drugs. Little is known about the latex productivity and bleeding methods in mangabeira, which is usually utilized in extractive way for fruit production. Aiming to broaden our knowledge about mangabeira latex production we evaluate the productivity associated with bleeding methods; environmental conditions; anatomical aspects from the bark and seasonal properties. As results we observed that the bleeding method commonly used in rubber tree is not appropriated to mangabeira; the most productive bleeding method was using a knife in stalk region. The bark thickness and lactiferous vessels number are associated with latex production. Anatomical analysis showed that the bark in mangabeira is thick and the lactiferous vessels are deeply localized, in this way some superficial bleeding methods are not able to reach the vessels. It was also observed that the increase in environmental temperature has a positive influence on the productivity of latex and that during the fruiting time the latex production is significantly lower. This probably occurs because the plant uses part of the secondary metabolites for fruit formation, which reduced the availability of these metabolites to latex production. © 2016, Universidade Federal de Santa Maria. All rights reserved.26393994
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