Estudo de propriedades críticas em sistemas complexos: método de procura automática em sistemas tipo Ising e percolação de longo alcance

The new technique for automatic search of the order parameters and critical properties is applied to several well-know physical systems, testing the efficiency of such a procedure, in order to apply it for complex systems in general. The automatic-search method is combined with Monte Carlo simulations, which makes use of a given dynamical rule for the time evolution of the system. In the problems inves¬tigated, the Metropolis and Glauber dynamics produced essentially equivalent results. We present a brief introduction to critical phenomena and phase transitions. We describe the automatic-search method and discuss some previous works, where the method has been applied successfully. We apply the method for the ferromagnetic fsing model, computing the critical fron¬tiers and the magnetization exponent (3 for several geometric lattices. We also apply the method for the site-diluted ferromagnetic Ising model on a square lattice, computing its critical frontier, as well as the magnetization exponent f3 and the susceptibility exponent 7. We verify that the universality class of the system remains unchanged when the site dilution is introduced. We study the problem of long-range bond percolation in a diluted linear chain and discuss the non-extensivity questions inherent to long-range-interaction systems. Finally we present our conclusions and possible extensions of this work

Efeitos das inomogeneidades da matéria em Cosmologias Aceleradas

The recent observational advances of Astronomy and a more consistent theoretical framework turned Cosmology in one of the most exciting frontiers of contemporary science. In this thesis, homogeneous and inhomogeneous Universe models containing dark matter and different kinds of dark energy are confronted with recent observational data. Initially, we analyze constraints from the existence of old high redshift objects, Supernovas type Ia and the gas mass fraction of galaxy clusters for 2 distinct classes of homogeneous and isotropic models: decaying vacuum and X(z)CDM cosmologies. By considering the quasar APM 08279+5255 at z = 3.91 with age between 2-3 Gyr, we obtain 0,2 < OM < 0,4 while for the j3 parameter which quantifies the contribution of A( t) is restricted to the intervalO, 07 < j3 < 0,32 thereby implying that the minimal age of the Universe amounts to 13.4 Gyr. A lower limit to the quasar formation redshift (zJ > 5,11) was also obtained. Our analyzes including flat, closed and hyperbolic models show that there is no an age crisis for this kind of decaying A( t) scenario. Tests from SN e Ia and gas mass fraction data were realized for flat X(z)CDM models. For an equation of state, úJ(z) = úJo + úJIZ, the best fit is úJo = -1,25, úJl = 1,3 and OM = 0,26, whereas for models with úJ(z) = úJo+úJlz/(l+z), we obtainúJo = -1,4, úJl = 2,57 and OM = 0,26. In another line of development, we have discussed the influence of the observed inhomogeneities by considering the Zeldovich-Kantowski-DyerRoeder (ZKDR) angular diameter distance. By applying the statistical X2 method to a sample of angular diameter for compact radio sources, the best fit to the cosmological parameters for XCDM models are OM = O, 26,úJ = -1,03 and a = 0,9, where úJ and a are the equation of state and the smoothness parameters, respectively. Such results are compatible with a phantom energy component (úJ < -1). The possible bidimensional spaces associated to the plane (a , OM) were restricted by using data from SNe Ia and gas mass fraction of galaxy clusters. For Supernovas the parameters are restricted to the interval 0,32 < OM < 0,5(20") and 0,32 < a < 1,0(20"), while to the gas mass fraction we find 0,18 < OM < 0,32(20") with alI alIowed values of a. For a joint analysis involving Supernovas and gas mass fraction data we obtained 0,18 < OM < 0,38(20"). In general grounds, the present study suggests that the influence of the cosmological inhomogeneities in the matter distribution need to be considered with more detail in the analyses of the observational tests. Further, the analytical treatment based on the ZKDR distance may give non-negligible corrections to the so-calIed background tests of FRW type cosmologies

Diet of the maned wolf (Chrysocyon brachyurus) and its role in seed dispersal on a cattle ranch in Brazil

The maned wolf Chrysocyon brachyurus is the largest canid inhabiting South America. Its geographic distribution includes the open fields of Brazil's central area, which is currently undergoing agricultural expansion. The diet of the maned wolf and its seasonal variation was determined on a dairy cattle ranch (Sao Luis farm, 566 ha) in the State of Minas Gerais, Brazil. From January to December faeces of the maned wolf were collected monthly (n = 150 scats; 397 food item occurrences). Twenty-nine taxa were identified from scats, 18 of animal origin (46% or 183 occurrences) and 11 of plants (54% or 214 occurrences). The fruits of Solanum lycocarpum were the dominant food item in our study (29%). Mammals contributed 13%, arthropods 12%, birds 11% and reptiles 2% of the food items. Arthropods and fruits were prevalent in the rainy season and mammals in the dry season. As expected for a heavily fanned region, frugivory results were at the lower end of the diversity scale (9-33 species) and included four old garden species. No previous study of the diet of maned wolf has registered as many species of Solanaceae as this one. Although dietary richness was lower, the main food items (wolf fruit, armadillos, rodents, birds) were the same as study sites in 'cerrado' and upland meadows. In this region, the open habitats occupied by the maned wolf were previously covered by Atlantic forest, suggesting that landscape modification such as cattle ranching has opened new frontiers for distribution expansion of the maned wolf. The impact of loss of dietary richness and the increase in Solanaceae on the survival of the maned wolf need to be evaluated.

The selective neurotoxin DSP-4 impairs the noradrenergic projections from the locus coeruleus to the inferior colliculus in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Turning math attractive to computer science students: an application-to-model approach

This paper describes an innovative approach to develop the understanding about the relevance of mathematics to computer science. The mathematical subjects are introduced through an application-to-model scheme that lead computer science students to a better understanding of why they have to learn math and learn it effectively. Our approach consists of a single one semester course, taught at the first semester of the program, where the students are initially exposed to some typical computer applications. When they recognize the applications' complexity, the instructor gives the mathematical models supporting such applications, even before a formal introduction to the model in a math course. We applied this approach at Unesp (Brazil) and the results include a large reduction in the rate of students that abandon the college and better students in the final years of our program.

Teaching real-time with a scheduler simulator

In this paper we describe a scheduler simulator for real-time tasks, RTsim, that can be used as a tool to teach real-time scheduling algorithms. It simulates a variety of preprogrammed scheduling policies for single and multi-processor systems and simple algorithm variants introduced by its user. Using RTsim students can conduct experiments that will allow them to understand the effects of each policy given different load conditions and learn which policy is better for different workloads. We show how to use RTsim as a learning tool and the results achieved with its application on the Real-Time Systems course taught at the B.Sc. on Computer Science at Paulista State University - Unesp - at Rio Preto.

A flexible curriculum for computer science undergraduate major

This paper describes an innovative approach to establish a CS curriculum, aiming flexibility and minimization of the time spent in the classrooms. This approach has been developed at the Paulista State University - Unesp - at São José do Rio Preto, and is producing very interesting results. The load reduction is achieved through a series of fundamental core and breadth courses that precede depth courses in specific areas. The flexibility comes as a side effect of the depth courses, which can be adapted without any changes in the core courses. In the following pages we fully describe our motivations, actions and results.

Social Panorama of Latin America 2010

Includes bibliography

Gaseous neurotransmitters and their role in anapyrexia

Mammals keep their body temperature (Tb) relatively constant even under a wide range of ambient temperature variation. However, in some particular situations it may be beneficial to increase or to decrease Tb. For instance, under hypoxic conditions, a regulated drop in Tb (anapyrexia) takes place which has been reported to be crucial for survival in a number of different species. This review highlights major advances in the research about nitric oxide (NO) and carbon monoxide (CO-where data are relatively less abundant), before focusing on the role played by these gaseous neuromediators in thermoregulation, under the conditions of euthermia and anapyrexia. Available data are consistent with the notion that both NO and CO, acting on the CNS, participate in thermoregulation, with NO decreasing Tb and CO increasing it. However further studies are required before definitive conclusions can be made as to their physiological mechanisms of action.

Molecular basis for defining the pineal gland and pinealocytes as targets for tumor necrosis factor

The pineal gland, the gland that translates darkness into an endocrine signal by releasing melatonin at night, is now considered a key player in the mounting of an innate immune response. Tumor necrosis factor (TNF), the first pro-inflammatory cytokine to be released by an inflammatory response, suppresses the translation of the key enzyme of melatonin synthesis (arylalkylamine-N-acetyltransferase, Aanat). Here, we show that TNF receptors of the subtype 1 (TNF-R1) are expressed by astrocytes, microglia, and pinealocytes. We also show that the TNF signaling reduces the level of inhibitory nuclear factor kappa B protein subtype A (NFKBIA), leading to the nuclear translocation of two NFKB dimers, p50/p50, and p50/RelA. The lack of a transactivating domain in the p50/p50 dimer suggests that this dimer is responsible for the repression of Aanat transcription. Meanwhile, p50/RelA promotes the expression of inducible nitric oxide synthase (iNOS) and the production of nitric oxide, which inhibits adrenergically induced melatonin production. Together, these data provide a mechanistic basis for considering pinealocytes a target ofTNF and reinforce the idea that the suppression of pineal melatonin is one of the mechanisms involved in mounting an innate immune response. © 2011 Carvalho-Sousa, da Silveira Cruz-Machado, Tamura, Fernandes, Pinato, Muxel, Cecon and Markus.

New contributions to the analysis of poverty: methodological and conceptual challenges to understanding poverty from a gender perspective

Includes bibliography

High tech garbage can help engineering colleges to improve hands-on education

This paper presents a discussion on the potential use of high tech garbage, including electronic waste (e-waste), as a source of mechanisms, sensors and actuators, that can be adapted to improve the reality of microprocessor systems labs, at low cost. By means of some examples, it is shown that entire subsystems withdrawn of high tech equipments can be easily integrated into existing laboratory infrastructure. As examples, first a precision positioning mechanism is presented, which was taken from a discarded commercial ink jet printer and interfaced with a microprocessor board used in the laboratory classes. Secondly, a read/write head and its positioning mechanism has been withdrawn of a retired CD/DVD drive and again interfaced with the microprocessor board. Students who have been using these new experiments strongly approve their inclusion in the lab schedules. © 2011 IEEE.

Using virtual worlds in distance learning environments

This paper presents two tools developed to facilitate the use and automate the process of using Virtual Worlds for educational purposes. The first tool has been developed to automatically create the classroom space, usually called region in the virtual world, which means, a region in the virtual world used to develop educational activities between professors, students and interactive objects. The second tool helps the process of creating 3D interactive objects in a virtual world. With these tools educators will be able to produce 3D interactive learning objects and use them in virtual classrooms improving the quality and appeal, for students, of their classes. © 2011 IEEE.