History teachers��� thinking about the nature of their subject

This paper addresses how secondary history teachers view the nature and purposes of their subject and how they think these views impact on their practice. Data were collected through individual qualitative interviews with eleven UK history teachers at the start of their careers. Their views on the nature of history are broadly empiricist with postmodern perspectives having been less influential. Their rationales for the subject emphasise broader educational purposes. The case for further emphasis on subject understandings in teacher education is made through a consideration of the implications of a lack of emphasis of more postmodern perspectives on classroom practice.

Permanence of stability for a class of system of differential equations with two delays

The paper studies a class of a system of linear retarded differential difference equations with several parameters. It presents some sufficient conditions under which no stability changes for an equilibrium point occurs. Application of these results is given. (c) 2007 Elsevier Ltd. All rights reserved.

STABILITY ANALYSIS WITH APPLICATIONS OF A TWO-DIMENSIONAL DYNAMICAL SYSTEM ARISING FROM A STOCHASTIC MODEL FOR AN ASSET MARKET

We analyze the stability properties of equilibrium solutions and periodicity of orbits in a two-dimensional dynamical system whose orbits mimic the evolution of the price of an asset and the excess demand for that asset. The construction of the system is grounded upon a heterogeneous interacting agent model for a single risky asset market. An advantage of this construction procedure is that the resulting dynamical system becomes a macroscopic market model which mirrors the market quantities and qualities that would typically be taken into account solely at the microscopic level of modeling. The system`s parameters correspond to: (a) the proportion of speculators in a market; (b) the traders` speculative trend; (c) the degree of heterogeneity of idiosyncratic evaluations of the market agents with respect to the asset`s fundamental value; and (d) the strength of the feedback of the population excess demand on the asset price update increment. This correspondence allows us to employ our results in order to infer plausible causes for the emergence of price and demand fluctuations in a real asset market. The employment of dynamical systems for studying evolution of stochastic models of socio-economic phenomena is quite usual in the area of heterogeneous interacting agent models. However, in the vast majority of the cases present in the literature, these dynamical systems are one-dimensional. Our work is among the few in the area that construct and study analytically a two-dimensional dynamical system and apply it for explanation of socio-economic phenomena.

Energy Storage for a Grid-Connected PV-System: A Feasibility Study

The work presented in this thesis concerns the dimensioning of an Energy Storage System (ESS) which will be used as an energy buffer for a grid-connected PV plant. This ESS should help managing the PV plant to inject electricity into the grid according to the requirements of the grid System Operator. It is desired to obtain a final production not below 1300kWh/kWp with a maximum ESS budget of 0.9���/Wp. The PV plant will be sited in Martinique Island and connected to the main grid. This grid is a small one where the perturbations due clouds in the PV generation are not negligible anymore. A software simulation tool, incorporating a model for the PV-plant production, the ESS and the required injection pattern of electricity into the grid has been developed in MS Excel. This tool has been used to optimize the relevant parameters defining the ESS so that the feed-in of electricity into the grid can be controlled to fulfill the conditions given by the System Operator. The inputs used for this simulation tool are, besides the conditions given by the System Operator on the allowed injection pattern, the production data from a similar PV-plant in a close-by location, and variables for defining the ESS. The PV production data used is from a site with similar climate and weather conditions as for the site on the Martinique Island and hence gives information on the short term insolation variations as well as expected annual electricity production. The ESS capacity and the injected electric energy will be the main figures to compare while doing an economic study of the whole plant. Hence, the Net Present Value, Benefit to Cost method and Pay-back period studies are carried on as dependent of the ESS capacity. The conclusion of this work is that it is possible to obtain the requested injection pattern by using an ESS. The design of the ESS can be made within an acceptable budget. The capacity of ESS to link with the PV system depends on the priorities of the final output characteristics, and it also depends on which economic parameter that is chosen as a priority.

O Prob��sica e a forma����o de professores no P��lo de Parnamirim: pol��tica de forma����o profissional no Rio Grande do Norte?

This work studies the thematic of the politics of formation of teachers in the Program of Professional Qualification for Basic Education (PROB��SICA) developed in the City of Parnamirim, Rio Grande do Norte. It has as its main objective to identify and to analyze the contribution of this politics of initial formation for the professional formation of teachers. To install the work, we will use the procedures of bibliographical research, documentary analysis, comment, structuralized interview, questionnaire-script and virtual research. In the analysis of the data, we trace a general view on PROB��SICA while initial formation along with the continued formation, pedagogical research, collaborative research and the exercise of the teaching profession, identifying the possibilities and limits of the Program in the direction to reach the objective considered in this work. From the inquiry, we construct the institutional land scope of the program in question, also focusing, the organizational aspects of its functioning. We have to take care about the results, we evidence that PROB��SICA is making the possible to access of the teachers in the educational service to the University, what the main aspect that consists, trying to prove eminent weak points in its systematic due to give to the organizational structure of this educational politics that does not count with curricular, institutional and financial the necessary conditions for the success of the professional formation of the teachers. The research will try to understand that the operationalization of the politics of formation in Parnamirim will be belong with it the main idea of the Educational Reformation in years of 1990, articulated to the neoliberal interests, that the responsibility for the problems of the public system of education attributed to the teachers, and that are not answered completely through the purpose of the professional formation, and ti seems that it does not define one global national politics that deals with seriousness to the questions the initial formation, permanent formation, pedagogical research, , career and conditions of work for the teachers

Histopathological analysis of the reproductive system of male dogs experimentally infected with Toxoplasma gondii

O presente trabalho teve como objetivo descrever eventuais altera����es histopatol��gicas no sistema reprodutor (test��culo e epid��dimo) de c��es machos experimentalmente infectados com Toxoplasma gondii. Para tal, 10 animais sorologicamente negativos para T. gondii foram selecionados e distribu��dos em tr��s grupos experimentais: GI - tr��s c��es inoculados com 2,0 x 10(5) oocistos da cepa P, GII - tr��s c��es infectados com 1,0 x 10(6) taquizo��tos da cepa RH e GIII - quatro c��es mantidos como controle. Pesquisa de anticorpos (IFI) contra T. gondii foi realizada. A infec����o por T. gondii confirmou-se pela soroconvers��o de todos os machos infectados a partir do 7�� e do 14�� dia p��s-inocula����o (DPI) para c��es que receberam taquizo��tos e oocistos respectivamente. Decorridos 70DPI, realizou-se, em todos os c��es, orquiectomia, e amostras (test��culo e epid��dimo) foram coletadas e processadas histologicamente para leitura em microsc��pio ��ptico. As seguintes altera����es foram diagnosticadas: infiltrado inflamat��rio mononuclear leve e moderado em epid��dimo, edema celular moderado, degenera����o hidr��pica e fibrose intersticial moderada em t��bulos semin��feros. Os resultados histopatol��gicos do presente trabalho, aliados ao isolamento do T. gondii em fragmentos de test��culo e epid��dimo pela imunoistoqu��mica, juntamente com os resultados encontrados na literatura por outros autores em diferentes tecidos, permitem inferir que as altera����es encontradas nos c��es infectados com o respectivo protozo��rio s��o sugestivas de infec����o toxopl��smica.

Root system of Panicum maximum Jacq. cv. IPR-86 Mil(e)over-capnio fertilized with nitrogen and submitted to rotational stocking

The effect of nitrogen on the root system of the species Panicum maximum Jacq. cv. IPR-86 Mil (e) over cap nio, under grazing, was evaluated. The N rates were 0; 150; 300 and 450 kg/ha. year. The root density was evaluated during pregrazing at five years of successive N application, in three depths (0-10; 10-20 and 20-40 cm) and the root growth at 7, 14, 21, and 35 days after grazing. The grazing method adopted was rotational stocking. Root length and root mass densities in pre-and post-grazing presented maximum values at rates 204, 206, 192, and 197 kg/ha of N, respectively. The root growth (in root length density) increased, on average, until 29 days after grazing at rates 0, 150, and 300 kg/ha; at 450 kg/ha N rate, the increase was linear. Independently of N rates, around 60 and 25% of IPR-86 Mil (e) over cap nio cultivar root system was concentrated in 0-10 and 10-20 cm depth, respectively.

Electricity, hot water and cold water production from biomass. Energetic and economical analysis of the compact system of cogeneration run with woodgas from a small downdraft gasifier

Wood gasification technologies to convert the biomass into fuel gas stand out. on the other hand, producing electrical energy from stationary engine is widely spread, and its application in rural communities where the electrical network doesn't exist is very required. The recovery of exhaust gases (engine) is a possibility that makes the system attractive when compared with the same components used to obtain individual heat such as electric power. This paper presents an energetic alternative to adapt a fixed bed gasifier with a compact cogeneration system in order to cover electrical and thermal demands in a rural area and showing an energy solution for small social communities using renewable fuels. Therefore, an energetic and economical analysis from a cogeneration system producing electric energy, hot and cold water, using wooden gas as fuel from a small-sized gasifier was calculated. The energy balance that includes the energy efficiency (electric generation as well as hot and cold water system; performance coefficient and the heat exchanger, among other items), was calculated. Considering the annual interest rates and the amortization periods, the costs of production of electrical energy, hot and cold water were calculated, taking into account the investment, the operation and the maintenance cost of the equipments. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.

Histopathology of the reproductive system of male sheep experimentally infected with Toxoplasma gondii

The aim of this study was to investigate the histopathological changes in reproductive system (testicles, epididymis, seminal vesicles, and prostate) of small male ruminants after Toxoplasma gondii infection. Eight sheep were inoculated with T. gondii: group I, four sheep (2.0 x 10(5) P-strain oocysts); group II, four sheep (1.0 x 10(6) RH-strain tachyzoites); and group III, two uninfected sheep maintained as control. Infection with T. gondii was confirmed by seroconversion (indirect fluorescent antibody test-IgG) in all the infected animals beginning on post-inoculation day (PID) 7. on PID 70, all the animals were euthanized and tissue samples (testicles, epididymis, seminal vesicles, and prostate) were collected and processed for histological analysis. The main changes detected were a focal mononuclear interstitial inflammatory infiltrate in the prostate and seminal vesicles; diffuse testicular degeneration associated with calcification foci and a multifocal mononuclear interstitial inflammatory infiltrate; and a mononuclear interstitial infiltrate and focal necrotic areas of the muscle fibers surrounding the seminal vesicles. The histopathological findings of this work, along with the detection of T. gondii in the examined parenchyma tissues (immunohistochemistry) and the results obtained by other authors examining different tissues, suggest that histological changes diagnosed in the reproductive system of rams infected with T. gondii are strongly suggestive of toxoplasmatic infection.

Karyotypic relationships among the tribes of Hypostominae (Siluriformes : Loricariidae) with description of XO sex chromosome system in a neotropical fish species

The family Loricariidae, with about 683 species, is one the largest fish families in the world. The subfamily Hypostominae was recently reviewed and is now divided in five tribes. With the main objective of contributing to a better understanding of the relationships of the members of the subfamily Hypostominae, cytogenetic analyses were conducted in seven species (three Hypostomini, three Pterygoplichthini and two Ancistrini) from Brazil and Venezuela. In Pterygoplichthini, all species show 2n = 52 chromosomes. In Hypostomini Hypostomus ancistroides has 2n = 68, H. regani 2n = 72 and Hypostomus goyazensis 2n = 72 chromosomes. In Ancistrini Ancistrus n. sp. 1 has 2n = 39/40 with a sex chromosome system of the type XX/X0, which is a novelty for neotropical fishes, and Ancistrus n. sp. 2 has 2n = 52 chromosomes. Six species have single Ag-NORs and two multiple Ag-NORs. The possible cytogenetic relationships among the species of Hypostominae are discussed.

Kinetics of photoinduced birefringence in the guest-host system of poly(methyl methacrylate) doped with azobenzene-containing crown ethers

The kinetics of the buildup and decay of photoinduced birefringence was examined in a series of host-guest systems: azobenzene-containing crown ethers, differing in the size of the crowns, dissolved in a poly (methyl methacrylate) matrix. In all samples, the kinetics of the buildup of the birefringence was reasonably described by a sum of two exponential functions, the time constants being inversely proportional to the intensity of the pumping light and the magnitudes of the signals at the saturation level depending on the pumping light intensity and sample thickness. The dark decays were best described by the stretched exponential function, with the characteristic parameters (time constant and stretch coefficient) being practically independent of the type of crown ether. The time constants of the signal decay were orders of magnitude shorter than the respective constants of the dark isomerization of the azo crown ethers, thus indicating that the process controlling the decay was a relaxation of the polymer matrix and/or a rearrangement of the flexible parts of the crowns. (C) 2007 Wiley Periodicals, Inc.

Cognitive Deficits in Machado-Joseph Disease Correlate with Hypoperfusion of Visual System Areas

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Anatomy of the male reproductive system of Phrynops geoffroanus (Testudines: Chelidae).

The reproductive system of male Phrynops geoffroanus adults is macroscopically described and the variation in testicular biometry is evaluated. A pair of oval testes is connected by the efferent ductules to the epididymis, which continue as deferent ducts, which emerge in the penis. The volume of the gonads showed the highest averages during spring and summer months. GSI varied significantly throughout the year, with the highest averages observed in the months that correspond to the end of spring and the beginning of summer, when the reproduction of the species takes place, and the lowest averages were seen in winter, suggesting a cyclical testicular activity.