Redução da interferência de Brachiaria plantaginea (link) hitch. em milho através de capinas e aplicação de herbicidas em diferentes épocas

O rendimento de grãos de milho é afetado pela interferência com as plantas daninhas, que pode variar em função da eficiência e da época de realização do método de controle utilizado no manejo da cultura. O objetivo deste trabalho foi determinar os efeitos da aplicação de herbicidas e de capinas em diferentes épocas sobre o controle de plantas daninhas e o rendimento de grãos na cultura do milho. O experimento foi instalado no sistema convencional de preparo do solo em Eldorado do Sul (RS), no ano agrícola 1997/98. A espécie de planta daninha predominante na área experimental foi Brachiaria plantaginea (BRAPL), em infestação média de 285 plantas por m². Os tratamentos foram constituídos pela aplicação isolada, seqüencial ou em mistura em tanque, em diferentes doses e épocas, dos herbicidas atrazine, atrazine + óleo vegetal, metolachlor e nicosulfuron. Todos os tratamentos com herbicidas foram correspondidos por tratamentos em que se utilizou capina manual com início na mesma época de aplicação dos herbicidas. O controle realizado em pré-emergência ou no início do desenvolvimento da cultura proporcionou maior rendimento de grãos, mesmo com a diminuição do controle de BRAPL no final do ciclo. As aplicações seqüenciais de herbicidas proporcionaram maior rendimento de grãos do que as misturas em tanque. Os rendimentos de grãos obtidos com a aplicação de herbicidas nas diversas épocas não foram diferentes em relação às suas respectivas capinas.

Morfologia dos ovários, tubas uterinas e útero em catetos (Tayassu tajacu, Linnaeus, 1758) e queixadas (Tayassu pecari, Link, 1795)

Estudaram-se a morfologia externa, a sintopia e os dados métricos dos ovários, tubas uterinas e útero em 14 fêmeas adultas de cateto (12 adultas, uma prenhe e uma jovem) e em sete fêmeas de queixada (três jovens e quatro adultas), e o material, após fixação em solução aquosa de formol a 10%, foi dissecado. O material foi obtido na Universidade Federal de Uberlândia (UFU) - Campus Palotina e na Universidade Estadual Paulista - Campus de Ilha Solteira. Os ovários apresentaram-se ovalados e de superfície irregular, quando havia corpo lúteo ou folículo. As tubas uterinas mostraram-se longas, finas e enoveladas e terminando numa extremidade ovárica com fímbrias; a comunicação com o útero ocorreu de maneira contínua. Uma bolsa ovárica parcial, com um largo orifício, contém o ovário. O útero, bicórneo, apresentou um corpo curto e uma cérvix longa, com projeções anulares para o canal cervical, conferindo-lhe luz espiralada. Os cornos uterinos mostraram-se curtos, voltados ventralmente e em forma de hélice.

Vascularização dos ovários, tubas uterinas e útero em catetos (Tayassu tajacu, Linnaeus, 1758) e queixadas (Tayassu pecari, Link, 1795)

Estudou-se a vascularização arterial em nove fêmeas adultas de cateto, incluindo uma jovem e uma gestante, e em seis fêmeas de queixada (três jovens e três adultas). Para este estudo as artérias foram injetadas com solução de látex Neoprene 650 corado e após fixação de formol foram dissecadas. O material foi obtido na Universidade Federal de Uberlândia (UFU) - Campus Palotina e na Universidade Estadual Paulista - Campus de Ilha Solteira. As artérias responsáveis pela irrigação sangüínea dos ovários, tubas uterinas e útero são as artérias útero-ováricas, que emitem as artérias uterinas e ováricas, e as artérias vaginais, estando presentes em todas as amostras, porém variando suas origens. As artérias ováricas emitiram ramos para os ovários, tubas uterinas (ramos tubáricos) e extremidades craniais dos cornos uterinos (ramos tubo-uterinos) e as artérias uterinas enviaram ramos para os cornos uterinos, corpos uterinos e porções craniais da cérvix uterina. As artérias vaginais enviaram ramos para a cérvix e a vagina.

Automation and cybernetics: Control of a flexible one-link manipulator

States that control is of the essence in cybernetics. Summarizes the dynamic equations for a flexible one-link manipulator moving in the horizontal plane. Employs the finite element method, based on elementary beam theory, during the process of formulation. Develops and instruments a one-link flexible manipulator in order to control its vibration modes. Uses a simple second-order vibration model which permits vibrations on the rod to be estimated using the hub angle. The validation of the dynamic model and the structural analysis of the flexible manipulator is reached using proper infrared cameras and active light sources for determining actual positions of objects in space. Shows that the performance of the control is satisfactory, even under perturbation action.

Contributions of ethnobiology to the conservation of tropical rivers and streams

1. This study aimed to link basic ethnobiological research on local ecological knowledge (LEK) to the conservation of Brazilian streams, based on two case studies: original data on LEK of fishermen about freshwater fish in the Negro River, Amazon, and previously published data about LEK of farmers on the ecological relationship between forest and streams in the Macabuzinho catchment, Atlantic Forest.2. Information was obtained from fishermen through interviews using standard questionnaires containing open-ended questions. Informants for interview were selected either following some defined criteria or applying the 'snowball' method.3. Fishermen's LEK about the diets and habitats of 14 fish species in the Negro River provided new biological information on plant species that are eaten by fish, in addition to confirming some ecological patterns from the biological literature, such as dependence of fish on forests as food sources.4. In the Atlantic Forest, a comparison between farmers' LEK and a rapid stream assessment in the farmers' properties indicated that farmers tended to overestimate the ecological integrity of their streams. Farmers recognized at least 11 forest attributes that correspond to the scientific concept of ecosystem services. Such information may be useful to promote or enhance dialogue among farmers, scientists and managers.5. These results may contribute to the devising of ecosystem management measures in the Negro River, aimed to conserve both rivers and their associated floodplain forests, involving local fishermen. In the Atlantic Forest, we proposed some initiatives, such as to allow direct economic use of their forests to conciliate conflicting perceptions of farmers about ecological benefits versus economic losses from reforestation. Despite their cultural, environmental and geographical differences, the two study cases are complementary and cost-effective and promising approaches to including LEK in the design of ecological research. Copyright (C) 2007 John Wiley & Sons, Ltd.

História na Educação Matemática – um estudo sobre trabalhos publicados no Brasil nos últimos cinco anos

In this paper we report a study on research in the field of History in Mathematics Education conducted in Brazil in the last five years. We evaluate studies that are theoretical or report experiences on the support found in history that can contribute to the situations of teaching and learning of mathematics, based on the Proceedings of Seminarios Nacionais de Historia da Matematica and Encontros Luso-Brasileiros de Historia da Matematica. Examining the interests, directions and focus of research in the field, we found that the vast majority of studies address specific issues of History of Mathematics, and the number of studies on History in Mathematics Education is still very low. We note that, in the last five years, the arguments in favor of the teaching potential of the History of Mathematics, which is very present in the speech of teachers and managers of public education, has not yet been materialized in experiments or investigations to promote this link effectively.

Taxonomic comments and an identification key to species for the Smooth-hound sharks genus Mustelus Link, 1790 (Chondrichthyes: Triakidae) from the Western South Atlantic.

Five species of smooth-hound sharks genus Mustelus (Family Triakidae) are know in the western South Atlantic, as follows: Mustelus canis (Mitchell 1815); Mustelus fasciatus (Garman 1913); Mustelus higmani Springer & Lowe 1963; Mustelus norrisi Springer 1939; and Mustelus schmitti Springer 1939. In the present paper, new data on the anatomy, morphometrics and meristic characters are given. Taxonomic aspects and comparison between the species are discussed. Most general body morphologic measurements and proportions are useless as a tool for species identification, since many of them show remarkable intraspecific variations. Head proportions and structures related seem to be a more adequate procedure to identify the species of Mustelus. The labial folds proportions, internasal distance and orbit diameter were the most useful character to separate the western South Atlantic species. The buccopharingeal pattern of denticles as well as tooth counts not was useful to distinguish the Mustelus species from western South Atlantic adequately, due great intraspecific variation.

Opportunities for trade and investment between Latin America and Asia-Pacific: the link with APEC

Includes bibliography

Using serial bluetooth converters as a sensor link in networked control systems

Networked control systems (NCS) are distributed control system in which sensors, actuators and controllers are physically separated and connected through communication networks. NCS represent the evolution of networked control architectures providing greater modularity and control decentralization, ease maintenance and diagnosis and lower cost of implementation. A recent trend in this research topic is the development of NCS using wireless networks which enable interoperability between existing wired and wireless systems. This paper presents the feasibility analysis of using a serial RS-232 to Bluetooth converter as a wireless sensor link in NCS. In order to support this investigation, relevant performance metrics for wireless control applications such as jitter, time delay and messages lost are highlighted and calculated to evaluate the converter capabilities. In addition the control performance of an implemented motor control system using the converter is analyzed. Experimental results led to the conclusion that serial RS-232 Bluetooth converters can be used to implement wireless networked control systems (WNCS) providing transmission rates and closed control loop times which are acceptable for NCS applications. © 2011 IEEE.

Resonant (P+RES) controller applied to voltage source inverter with minimum DC link capacitor

Voltage source inverters use large electrolytic capacitors in order to decouple the energy between the utility and the load, keeping the DC link voltage constant. Decreasing the capacitance reduces the distortion in the inverter input current but this also affects the load with low-order harmonics and generate disturbances at the input voltage. This paper applies the P+RES controller to solve the challenge of regulating the output current by means of controlling the magnitude of the current space vector, keeping it constant thus rejecting harmonic disturbances that would otherwise propagate to the load. This work presents a discussion of the switching and control strategy. © 2011 IEEE.

Chronic Ethanol Consumption Alters All-Trans-Retinoic Acid Concentration and Expression of Their Receptors on the Prostate: A Possible Link Between Alcoholism and Prostate Damage

Background: Ethanol (EtOH) alters the all-trans-retinoic acid (ATRA) levels in some tissues. Retinol and ATRA are essential for cell proliferation, differentiation, and maintenance of prostate homeostasis. It has been suggested that disturbances in retinol/ATRA concentration as well as in the expression of retinoic acid receptors (RARs) contribute to benign prostate hyperplasia and prostate cancer. This study aimed to evaluate whether EtOH consumption is able to alter retinol and ATRA levels in the plasma and prostate tissue as well as the expression of RARs, cell proliferation, and apoptosis index. Methods: All animals were divided into 4 groups (n = 10/group). UChA: rats fed 10% (v/v) EtOH ad libitum; UChACo: EtOH-naïve rats without access to EtOH; UChB: rats fed 10% (v/v) EtOH ad libitum; UChBCo: EtOH-naïve rats without access to EtOH. Animals were euthanized by decapitation after 60 days of EtOH consumption for high-performance liquid chromatography and light microscopy analysis. Results: EtOH reduced plasma retinol concentration in both UChA and UChB groups, while the retinol concentration was not significantly different in prostate tissue. Conversely, plasma and prostate ATRA levels increased in UChB group compared with controls, beyond the up-regulation of RARβ and -γ in dorsal prostate lobe. Additionally, no alteration was found in cell proliferation and apoptosis index involving dorsal and lateral prostate lobe. Conclusions: We conclude that EtOH alters the plasma retinol concentrations proportionally to the amount of EtOH consumed. Moreover, high EtOH consumption increases the concentration of ATRA in plasma/prostate tissue and especially induces the RARβ and RARγ in the dorsal prostate lobe. EtOH consumption and increased ATRA levels were not associated with cell proliferation and apoptosis in the prostate. © 2012 by the Research Society on Alcoholism.

Institutions and growth: can human capital be a link?

Includes bibliography

Evolution of the link between selective anti-poverty policies and social sectors policies

Includes bibliography

Care: the missing link in economic analysis?

Includes bibliography