Regression towards the mode

We propose a semi-parametric mode regression estimator for the case in which the variate of interest is continuous and observable over its entire un- bounded support. The estimator is semi-parametric in that the conditional mode is specified as a parametric function, but only mild assumptions are made about the nature of the conditional density of interest. We show that the proposed estimator is consistent and has a tractable asymptotic distribution. Simulation results and an empirical illustration are provided to highlight the practicality and usefulness of the estimator.

Desigualdades sociais e acesso seletivo ao ensino superior no Brasil no período 1994-2001

O ensino superior no Brasil experimentou um significativo processo de expansão, iniciado em meados da década de 90. A retomada do crescimento do número de matrículas, após um período de estagnação na década anterior, ocorreu num contexto de aumento do número de concluintes do nível médio, e acentuou-se a partir de 1997, sob os efeitos das políticas governamentais para a ampliação da oferta de vagas. O setor privado foi o principal responsável pelo processo de expansão, em vista da redução das restrições legais para a criação de novos cursos e instituições. Este trabalho investiga as relações entre as chances de ingresso e o risco de evasão e algumas características sociais e familiares dos estudantes, no contexto da expansão recente deste nível de ensino no Brasil. A análise foi baseada nos dados da Pesquisa Mensal do Emprego do IBGE de 1994 a 2001. Os resultados indicam que tanto o ingresso quanto a evasão são fortemente condicionados pelas características sociais dos estudantes, que as chances de ingresso reduziram-se para o conjunto dos concluintes do ensino médio e que o risco de evasão manteve-se constante. Também não foram observadas alterações nas desigualdades de acesso entre estudantes de diferentes grupos sociais no período

A LOW COST PACKAGE FOR THE ANALYSIS OF HUMAN BODY KINEMATICS

The application of the analytical methods of Classical Mechanics has made possible the modelling and quantification of relatively simple motional situations. Only recently, however, with the development of computer integrated systems of kinematic data acquisition and processing, has this branch of Biomechanics acquired a lively momentum. The data for the study of the kinematics of human movement has essentially been obtained with techniques of goniometry, accelerometry and cine- and videophotogrammetry and then processed to provide information on the time histories of the co-ordinates of representative points on the surface of the body. This processing can be done automatically by data acquisition systems such as the Peak Performance, the Elite Motion Analyser, the MacReflex System Motion Analysis System and the Ariel Performance Analysis System (APAS), systems which are, however, far too expensive for the great majority of the researchers and field workers. We have developed a simple and portable PC computer software package which provides facilities for image processing such as the use of several filtering and zooming schemes, image conversion, as well as adjustment of brilliance and contrast. The images are recorded with a video camera and stored frame by frame on disc with a frame grabber and are interactively edited for processing. The image resolution may vary from 800 x 600 pixels with 65 536 colours to 1024 x 768 pixels and 256 colours. The package also includes the means for the acquisition of the co-ordinates of relevant marker points on the body segments and for their export to another package we have developed (Ferreira & Correia da Silva. 1991) which is capable of quantifying the kinematics of the body movement as well as of simulating alternative segment trajectories. Reference: Ferreira. C. & K.Correia da Silva(1991). "John- a Three- Dimensional Model for the Simulation of Human Movement". Proc. First Congress on Computer Science and New Technologies, Malaga

Jack bean (Canavalia ensiformis) urease induces eicosanoid-modulated hemocyte aggregation in the Chagas' disease vector Rhodnius prolixus

AbstractUreases are multifunctional proteins that display biological activities independently of their enzymatic function, such as induction of exocytosis and insecticidal effects. Rhodnius prolixus, a major vector of Chagas' disease, is a model for studies on the entomotoxicity of jack bean urease (JBU). We have previously shown that JBU induces the production of eicosanoids in isolated tissues of R. prolixus. In insects, the immune response comprises cellular and humoral reactions, and is centrally modulated by eicosanoids. Cyclooxygenase products signal immunity in insects, mainly cellular reactions, such as hemocyte aggregation. In searching for a link between JBU's toxic effects and immune reactions in insects, we have studied the effects of this toxin on R. prolixus hemocytes. JBU triggers aggregation of hemocytes after injection into the hemocoel and when applied to isolated cells. On in vitro assays, the eicosanoid synthesis inhibitors dexamethasone (phospholipase A2 indirect inhibitor) and indomethacin (cyclooxygenase inhibitor) counteracted JBU's effect, indicating that eicosanoids, more specifically cyclooxygenase products, are likely to mediate the aggregation response. Contrarily, the inhibitors esculetin and baicalein were inactive, suggesting that lipoxygenase products are not involved in JBU's effect. Extracellular calcium was also necessary for JBU's effect, in agreement to other cell models responsive to ureases. A progressive darkening of the medium of JBU-treated hemocytes was observed, suggestive of a humoral response. JBU was immunolocalized in the cultured cells upon treatment along with cytoskeleton damage. The highest concentration of JBU tested on cultured cells also led to nuclei aggregation of adherent hemocytes. This is the first time urease has been shown to affect insect hemocytes, contributing to our understanding of the entomotoxic mechanisms of action of this protein

The Rio Games Legacy in Mobility: Challenges Beyond Infrastructure

The City of Rio de Janeiro, Brazil, a city of 6.5 million inhabitants, had several years to plan, invest, and prepare for the 2016 Olympic and Paralympic Games. A significant part of these efforts were in mobility infrastructure and operations, as they would become a fundamental legacy for the city. Silva, Maiolino and Torres, who were involved in these efforts in various capacities, discuss this experience and some of the challenges that go beyond investments in infrastructure such as behavior and operational changes

On Aharonov-Casher bound states

In this work bound states for the Aharonov-Casher problem are considered. According to Hagen's work on the exact equivalence between spin-1/2 Aharonov-Bohm and Aharonov-Casher effects, is known that the $\boldsymbol{\nabla}\cdot\mathbf{E}$ term cannot be neglected in the Hamiltonian if the spin of particle is considered. This term leads to the existence of a singular potential at the origin. By modeling the problem by boundary conditions at the origin which arises by the self-adjoint extension of the Hamiltonian, we derive for the first time an expression for the bound state energy of the Aharonov-Casher problem. As an application, we consider the Aharonov-Casher plus a two-dimensional harmonic oscillator. We derive the expression for the harmonic oscillator energies and compare it with the expression obtained in the case without singularity. At the end, an approach for determination of the self-adjoint extension parameter is given. In our approach, the parameter is obtained essentially in terms of physics of the problem.Comment: 11 pages, matches published versio

Binding affinities and activation of Asp712Ala and Cys100Ser mutated kinin B1 receptor forms suggest a bimodal scheme for the molecule of bound-DABK

AbstractMutant forms of kinin B1 receptor (B1R) and analogs of the full agonist des-Arg9-bradykinin (DABK) were investigated aiming to verify the importance of selected receptor residues and of each agonist-peptide residue in the specific binding and activation. Linked by a specific disulfide bond (Cys100–Cys650), the N-terminal (Nt) and the EC3 loop C-terminal (Ct) segments of angiotensin II (AngII) receptor 1 (AT1R) have been identified to form an extracellular site for binding the agonist Nt segment (Asp1 and Arg2 residues). Asp712 residue at the receptor EC3 loop binds the peptide Arg2 residue. By homology, a similar site might be considered for DABK binding to B1R since this receptor contains the same structural elements for composing the site in AT1R, namely the disulfide bond and the EC3 loop Asp712 residue. DABK, Alan-DABK analogs (n=Ala1-, Ala2-, Ala3-, Ala4-, Ala5-, Ala6-, Ala7-, Ala8-DABK), and other analogs were selected to binding wild-type, Asp712Ala and Cys100Ser mutated B1R receptors. The results obtained suggested that the same bimodal scheme adopted for AngII-AT1R system may be applied to DABK binding to B1R. The most crucial similarity in the two cases is that the Nt segments of peptides equally bind to the homologous Asp712 residue of both AT1R and B1R extracellular sites. Confirming this preliminary supposition, mutation of residues located at the B1R extracellular site as EC3 loop Asp712 and Cys100 caused the same modifications in biological assays observed in AT1R submitted to homologous mutations, such as significant weakening of agonist binding and reduction of post-receptor-activation processes. These findings provided enough support for defining a site that determines the specific binding of DABK to B1R receptors