84 research outputs found
Impact of leptin deficiency on male tibia and vertebral body 3D bone architecture independent of changes in body weight
Leptin an adipokine with potent effects on energy balance and body weight plays an important role in defining bone architecture in growing mammals. However, major changes in body weight can also influence morphology of trabecular and cortical bone. Therefore, we examined the impact of leptin deficiency on tibia and vertebral body 3D bone architecture independent of changes in body weight. Furthermore, advances in computational 3D image analysis suggest that average morphological values may mask regional specific differences in trabecular bone thickness. The study utilized leptin-deficient Ob/Ob mice (n = 8) weight-paired to C57BL/6 (C57) control mice (n = 8) which were split into either lean or obese groups for 24 ± 2 weeks. Whole tibias and L3 vertebrae were fixed before high resolution microcomputed tomography (μCT) scanning was performed. Leptin deficiency independent of body weight reduced tibia cortical bone volume, trabecular bone volume/tissue volume, number, and mineral density. Mean tibia trabecular thickness showed no significant differences between all groups; however, significant changes in trabecular thickness were found when analyzed by region. This study demonstrates that leptin deficiency significantly impacts tibia and vertebral body trabecular and cortical bone 3D architecture independent of changes in body weight
Information-Geometric Indicators of Chaos in Gaussian Models on Statistical Manifolds of Negative Ricci Curvature
A new information-geometric approach to chaotic dynamics on curved
statistical manifolds based on Entropic Dynamics (ED) is proposed. It is shown
that the hyperbolicity of a non-maximally symmetric 6N-dimensional statistical
manifold M_{s} underlying an ED Gaussian model describing an arbitrary system
of 3N degrees of freedom leads to linear information-geometric entropy growth
and to exponential divergence of the Jacobi vector field intensity, quantum and
classical features of chaos respectively.Comment: 8 pages, final version accepted for publicatio
Modified Brans-Dicke theory of gravity from five-dimensional vacuum
We investigate, in the context of five-dimensional (5D) Brans-Dicke theory of
gravity, the idea that macroscopic matter configurations can be generated from
pure vacuum in five dimensions, an approach first proposed in the framework of
general relativity. We show that the 5D Brans-Dicke vacuum equations when
reduced to four dimensions lead to a modified version of Brans-Dicke theory in
four dimensions (4D). As an application of the formalism, we obtain two
five-dimensional extensions of four-dimensional O'Hanlon and Tupper vacuum
solution and show that they lead two different cosmological scenarios in 4D.Comment: 9 page
Molecular-assisted selection for resistance to cassava mosaic disease in Manihot esculenta Crantz
The geminivirus complex known as cassava mosaic disease (CMD) is one of the most devastating viruses for cassava (Manihot esculenta Crantz). The aim of this study was to use molecular-assisted selection (MAS) to identify CMD-resistant accessions and ascertain promising crosses with elite Brazilian varieties. One thousand two hundred twenty-four accessions were genotyped using five molecular markers (NS169, NS158, SSRY028, SSRY040 and RME1) that were associated with resistance to CMD, along with 402 SNPs (single-nucleotide polymorphism). The promising crosses were identified using a discriminant analysis of main component (DAPC), and the matrix of genomic relationship was estimated with SNP markers. The CMD1 gene, previously described in M. glaziovii, was not found in M. esculenta. In contrast, the CMD2 gene was found in 5, 4 and 5 % of cassava accessions, with flanking markers NS169+RME1, NS158+RME1 and SSRY28+RME1, respectively. Only seven accessions presented all markers linked to the CMD resistance. The DAPC of the seven accessions along with 17 elite cassava varieties led to the formation of three divergent clusters. Potential sources of resistance to CMD were divided into two groups, while the elite varieties were distributed into three groups. The low estimates of the genomic relationship (ranging from -0.167 to 0.681 with an average of 0.076) contributed to the success in identifying contrasting genotypes. The use of MAS in countries where CMD is a quarantine disease constitutes a successful strategy not only for identifying the resistant accessions but also for determining the promising crosses
Recovery of copper (II) absorbed in biomass of Cladosporium cladosporioides
The biosorption process, characterized by the use of biomass for removing metals from aqueous solutions, is an attractive technology using inactive and dead biomasses to remove heavy metals from aqueous solutions in the absence of metabolic activity necessary for intracellular accumulation. The desorption process, which concentrates the metal previously absorbed for possible reuse, is also important. The desorption of copper (Cu) (II) associated with the biomass of Cladosporium cladosporioides (Fres) de Vries was evaluated following the biosorption process (adsorption). Specifically, four eluents were used (all at a concentration 0.1 mol L-1), sulfuric acid, hydrochloric acid, ethylenediaminetetraacetate disodium and calcium chloride, as well as the recovery of Cu (II) desorbed as copper sulfate. After 120 h, 97 % of Cu in solution had been adsorbed. C. cladosporioides can efficiently adsorb Cu (II). Further, 0.1 mol L-1 sulfuric acid was viable and the most efficient for the desorption of the absorbed metal, while ensuring viability of C. cladosporioides after desorption, which is important for the reuse of the biomass in cycles of sorption-desorption
Análise da atividade e gasto fisiolĂłgico dos catadores de resĂduos sĂłlidos: a percepção da terapia ocupacional
The world’s transformation in the market has been causing changes in the working class. As those changes have come, the market calls for a high capacity from the workers. Due to that, the unemployment rate has increased and induced a new type of class worker: the Recyclable Material Collectors. In this job, the role of the collector is to return the materials to their commodity chain, and to accomplish this, two methods of collecting are used: one with a truck and the other with a manual collector car. This is one type of occupation which has an extenuating work time, where the worker is exposed to a high ergonomic risk. This study, which was labored from a quantitative and qualitative approach to exploratory method and field research, is intended to compare which collecting technique can be less weariness to the worker. To the purpose of comparison of the physiological work weight, the participants used the Polar FT7 frequency counter, which generated, in graphic form, the performance of the collector in both methods. According to the values presented, was concluded that three of the four participants had a higher physiological weariness by using the manual car collecting approach, concluding that this method is the one that brings most effort to the worker. Considering the results obtained in this research, it was possible to observe that the use of the manual car causes a higher damage to the health of the recyclable material collector.A transformação no mundo do trabalho tem causado mudanças no perfil da classe
trabalhadora. Cada vez mais, o mercado de trabalho requer exigĂŞncias e, como decorrĂŞncia
disso, a taxa de desemprego aumentou e fez surgir uma nova profissĂŁo, a de Catadores de
Materiais Recicláveis. A função do catador é a de devolver os materiais à sua cadeia
produtiva e, para isso, existem dois métodos de coleta: com o caminhão e com o carro manual
de coleta. Essa Ă© uma profissĂŁo que possui jornadas de trabalho extenuantes, nas quais o
trabalhador está exposto a riscos ergonômicos. Esse estudo foi elaborado a partir de uma
abordagem quantitativa e qualitativa de método explorátorio e pesquisa de campo; pretende
comparar qual método de coleta causa menos desgaste ao trabalhador. Para fins de
comparação da carga fisiolĂłgica do trabalho, os participantes utilizaram o frequencĂmetro
Polar FT7 que gerou, em forma de gráfico, o desempenho do catador em ambos os métodos
de coleta. De acordo com os valores expostos, avaliou-se que, dos 4 participantes, 3
apresentaram um maior desgaste fisiológico no método de coleta com o carro manual, sendo
esta a forma pela qual o trabalhador realiza mais esforços. Considerando os resultados obtidos
nessa pesquisa, foi possĂvel observar que o uso do carro manual de coleta causa um maior
prejuĂzo Ă saĂşde do catador de materiais recicláveis
- …