Actitudes de los adolescentes hacia personas con discapacidad : un estudio con alumnos de polimodal en la zona norte del conurbano bonaerense

Resumen: Con el objetivo de contribuir al conocimiento acerca de las actitudes de los adolescentes hacia las personas con discapacidad, y cómo el contacto con éstas influye en la visión que se posee de la discapacidad, se desarrolló un estudio descriptivo en base a una muestra no probabilística intencional compuesta por 265 adolescentes, estudiantes de la zona norte del Conurbano Bonaerense. Los datos muestran que los estudiantes presentan una actitud favorable hacia las personas con discapacidad y que la presencia del contacto genera diferencias en la percepción e interacción hacia ellas. Asimismo, se demuestra la relevancia que tiene a la hora de la expresión de las actitudes las variables: razón y frecuencia del contacto, sexo, especialización del curso y tipo del colegio al que asisten.

Ensayo : Psicología positiva: ¿Una nueva forma de hacer psicología?

El presente trabajo intenta mostrar el desarrollo de la Psicología Positiva (PP), desde su surgimiento (hace una década), como disciplina tendiente al estudio científico del funcionamiento psíquico óptimo de personas, grupos o instituciones, en detrimento del clásico interés en variables psicopatológicas. Se desarrollan los tres pilares de la PP, que constituyen vías de acceso para una vida plena: la vida placentera (incremento de emociones positivas), el compromiso (que puede lograrse experimentando estados de flow) y la vida con significado (aplicación de las fortalezas personales para el desarrollo de algo que trascienda al individuo) (Seligman, 2002). Recientemente, Seligman (2009) agregó un cuarto pilar de estudio: los vínculos positivos (la vida social) como vía de acceso a la felicidad. También se reflexiona sobre las intervenciones psicoterapéuticas en PP encaminadas hacia la mejora de los rasgos positivos, el cultivo de las fortalezas humanas y la ayuda que se da a los clientes para estimular el cambio positivo –y no sólo reducir lo negativo– (Seligman, 2002). Se exponen, además, los medios más usuales de divulgación de las investigaciones en PP y los programas educativos existentes. Por último, se reflexiona acerca del futuro de la PP: si se propone como una especialidad más de la psicología, o si se integra con otros campos del quehacer profesional del psicólogo.

Experimental Observation Of Electrical Instability Of Droplets On Dielectric Layer

Polydimethylsiloxane ( PDMS) has become the most widely used silicon-based organic polymer in bio-MEMS/NEMS devices. However, the inherent hydrophobic nature of PDMS hinders its wide applications in bio-MEMS/NEMS for efficient transport of liquids. Electrowetting is a useful tool to reduce the apparent contact angle of partially wetting conductive liquids and has been utilized widely in bio-MEMS/NEMS. Our experimental results show that the thin PDMS membranes exhibit good properties in electrowetting-on-dielectric. The electrical instability phenomenon of droplets was observed in our experiment. The sessile droplet lying on the PDMS membrane will lose its stability with the touch of the wire electrode to make the apparent contact angle change suddenly larger than 35 degrees. Contact mode can protect the dielectric layer from electrical breakdown effectively. Electrical breakdown process of dielectric layer was recorded by a high speed camera. It is found experimentally that a PDMS membrane of 4.8 mu m thick will not be destroyed due to the electric breakdown even at 800 V in the contact mode.

Plane strain asymptotic fields for cracks terminating at the interface between elastic and pressure-sensitive dilatant materials

The plane strain asymptotic fields for cracks terminating at the interface between elastic and pressure-sensitive dilatant material are investigated in this paper. Applying the stress-strain relation for the pressure-sensitive dilatant material, we have obtained an exact asymptotic solution for the plane strain tip fields for two types of cracks, one of which lies in the pressure-sensitive dilatant material and the other in the elastic material and their tips touch both the bimaterial interface. In cases, numerical results show that the singularity and the angular variations of the fields obtained depend on the material hardening exponent n, the pressure sensitivity parameter mu and geometrical parameter lambda.

Entre los despojos del peronismo. Esplendor y ocaso del Instituto de Filología de la Universidad de Buenos Aires (1927-1946)

Entre 1927 y 1946, el Instituto de Filología de la Universidad de Buenos Aires atravesó su época de esplendor, bajo la dirección del español Amado Alonso. En menos de veinte años, Alonso le confirió a su instituto no sólo una fuerte presencia en la cultura argentina, sino además un importante prestigio internacional. El Instituto se había hecho de un lugar reconocido en la cultura argentina; había sabido captar la atención de un nutrido grupo de discípulos; había comenzado a publicar sus propias colecciones de libros; se había puesto en contacto con la vasta gama que ofrecía la industria cultural argentina del período. Este fuerte arraigo en la Argentina le permitió alcanzar un alto puesto en la cultura hispanoamericana de su tiempo. Pero con la llegada del peronismo al poder el Instituto se vio sometido a fuertes presiones que llevaron a su virtual desmantelamiento.

La demanda de telefonía fija y móvil: Una aplicación de redes neuronales artificiales

[ES] El catalogar a un determinado bien o servicio como una de las «extensiones de los sentidos y las funciones humanas de la vista, el oído y el tacto», muestra la importancia del papel que desempeñan en nuestras vidas, muestra el desarrollo que alcanzaron impulsadas por las mismas necesidades de los seres humanos, muestra un mercado dinámico e importante. El servicio de telefonía móvil o celular es el desencadenador de estas expresiones y además tema de comentario, investigación y preocupación de comunidades científicas y organismos internacionales como el World Economic Forum de Davos.

Summary report on water quantity and quality studies of Vancouver Lake, Washington

Vancouver Lake, located adjacent to the Columbia River and just north of the Vancouver-Portland metropolitan area, is a "dying" lake. Although all lakes die naturally in geologic time through the process of eutrophication,* Vancouver Lake is dying more rapidly due to man's activities and due to the resultant increased accumulation of sediment, chemicals, and wastes. Natural eutrophication takes thousands of years, whereas man-made modifications can cause the death of a lake in decades. Vancouver Lake does, however, have the potential of becoming a valuable water resource asset for the area, due particularly to its location near the Columbia River which can be used as a source of "flushing" water to improve the quality of Vancouver Lake. (Document pdf contains 59 pages) Community interest in Vancouver Lake has waxed and waned. Prior to World War II, there were relatively few plans for discussions about the Lake and its surrounding land area. A plan to drain the Lake for farming was prohibited by the city council and county commissioners. Interest increased in 1945 when the federal government considered developing the Lake as a berthing harbor for deactivated ships at which time a preliminary proposal was prepared by the City. The only surface water connection between Vancouver Lake and the Columbia River, except during floods, is Lake River. The Lake now serves as a receiving body of water for Lake River tidal flow and surface flow from creeks and nearby land areas. Seasonally, these flows are heavily laden with sediment, septic tank drainage, fertilizers and drainage from cattle yards. Construction and gravel pit operations increase the sediment loads entering the Lake from Burnt Bridge Creek and Salmon Creek (via Lake River by tidal action). The tidal flats at the north end of Vancouver Lake are evidence of this accumulation. Since 1945, the buildup of sediment and nutrients created by man's activities has accelerated the growth of the large water plants and algae which contribute to the degeneration of the Lake. Flooding from the Columbia River, as in 1968, has added to the deposition in Vancouver Lake. The combined effect of these human and natural activities has changed Vancouver Lake into a relatively useless body of shallow water supporting some wildlife, rough fish, and shallow draft boats. It is still pleasant to view from the hills to the east. Because precipitation and streamflow are the lowest during the summer and early fall, water quantity and quality conditions are at their worst when the potential of the Lake for water-based recreation is the highest. Increased pollution of the Lake has caused a larger segment of the community to become concerned. Land use and planning studies were undertaken on the Columbia River lowlands and a wide variety of ideas were proposed for improving the quality of the water-land environment in order to enhance the usefulness of the area. In 1966, the College of Engineering Research Division at Washington State University (WSU0 in Pullman, Washington, was contacted by the Port of Vancouver to determine possible alternatives for restoring Vancouver Lake. Various proposals were prepared between 1966 and 1969. During the summer and fall of 1967, a study was made by WSU on the existing water quality in the Lake. In 1969, the current studies were funded to establish a data base for considering a broad range of alternative solutions for improving the quantity and quality of Vancouver Lake. Until these studies were undertaken, practically no data on a continuous nature were available on Vancouver Lake, Lake River, or their tributaries. (Document pdf contains 59 pages)

Hopwood Hall College: Touchscreen technology overtakes interactive whiteboards as interactive teaching tool of choice

Hopwood Hall is adopting the use of touch screen technology and gradually replacing its interactive whiteboards to improve access to interactive learning. The touch screen monitors connected to LCD TV’s provide a cheaper classroom build with technology that’s more user-friendly and better suited to classroom delivery. Until now, interactive boards had been the mainstay of classrooms but they created teaching barriers for staff including the additional software to learn and master. They are also expensive and often have usability issues with 'pens' not working or having a delay when used as the mouse tool.

Parasitology and pathology of marine organisms of the world ocean

The Symposium in which the communications, as they were called during the meeting, comprising this volume were presented was held at the Zoological Institute of the Academy of Sciences of the U.S.S.R. in Leningrad during 13 to 16 October 1981. Conducted as part of the cooperative program of the U.S.A.-U.S.S.R. Working Group on Biological Productivity and Biochemistry of the World Ocean, the Leningrad meeting was sponsored by the Academy of Sciences of the U.S.S.R. (the Zoological Institute) and the Ministry of Fisheries of the U.S.S.R. (The Scientific Council on Fish Diseases of the Ichthyological Commission). It was an extremely interesting and successful Symposium, offering all participants the opportunity to describe the results of their studies and reviews during the course of the formal presentations and direct interchange between scientists during breaks in the program and the organized and casual social activities. The facilities provided by the Zoological Institute were quite adequate and the assistance offered by its Director, O. A. Scarlato and his staff in organization,logistics, and translation was excellent. Several of our Soviet colleagues presided over the proceedings, as did I. All were businesslike and efficient, yet graceful and accommodating. To O. N. Bauer Jell the brunt of programmatic detail and follow-up. He bore his burdens well and, with Director Scarlato and his staff, including A. V. Gussev and others of the professional and technical staffs of the Zoological Institute, helped make our stay pleasant and the Symposium productive. These organizations and individuals deserve much credit and praise as well as the thanks of their American and British colleagues. (PDF file contains 141 pages.)

Estimation and inference for grasping and manipulation tasks using vision and kinesthetic sensors

This thesis presents a novel framework for state estimation in the context of robotic grasping and manipulation. The overall estimation approach is based on fusing various visual cues for manipulator tracking, namely appearance and feature-based, shape-based, and silhouette-based visual cues. Similarly, a framework is developed to fuse the above visual cues, but also kinesthetic cues such as force-torque and tactile measurements, for in-hand object pose estimation. The cues are extracted from multiple sensor modalities and are fused in a variety of Kalman filters.

A hybrid estimator is developed to estimate both a continuous state (robot and object states) and discrete states, called contact modes, which specify how each finger contacts a particular object surface. A static multiple model estimator is used to compute and maintain this mode probability. The thesis also develops an estimation framework for estimating model parameters associated with object grasping. Dual and joint state-parameter estimation is explored for parameter estimation of a grasped object's mass and center of mass. Experimental results demonstrate simultaneous object localization and center of mass estimation.

Dual-arm estimation is developed for two arm robotic manipulation tasks. Two types of filters are explored; the first is an augmented filter that contains both arms in the state vector while the second runs two filters in parallel, one for each arm. These two frameworks and their performance is compared in a dual-arm task of removing a wheel from a hub.

This thesis also presents a new method for action selection involving touch. This next best touch method selects an available action for interacting with an object that will gain the most information. The algorithm employs information theory to compute an information gain metric that is based on a probabilistic belief suitable for the task. An estimation framework is used to maintain this belief over time. Kinesthetic measurements such as contact and tactile measurements are used to update the state belief after every interactive action. Simulation and experimental results are demonstrated using next best touch for object localization, specifically a door handle on a door. The next best touch theory is extended for model parameter determination. Since many objects within a particular object category share the same rough shape, principle component analysis may be used to parametrize the object mesh models. These parameters can be estimated using the action selection technique that selects the touching action which best both localizes and estimates these parameters. Simulation results are then presented involving localizing and determining a parameter of a screwdriver.

Lastly, the next best touch theory is further extended to model classes. Instead of estimating parameters, object class determination is incorporated into the information gain metric calculation. The best touching action is selected in order to best discern between the possible model classes. Simulation results are presented to validate the theory.

Structural and Biophysical Characterization of Variants of the Mechanosensitive Channel of Large Conductance (MSCL)

The ability to sense mechanical force is vital to all organisms to interact with and respond to stimuli in their environment. Mechanosensation is critical to many physiological functions such as the senses of hearing and touch in animals, gravitropism in plants and osmoregulation in bacteria. Of these processes, the best understood at the molecular level involve bacterial mechanosensitive channels. Under hypo-osmotic stress, bacteria are able to alleviate turgor pressure through mechanosensitive channels that gate directly in response to tension in the membrane lipid bilayer. A key participant in this response is the mechanosensitive channel of large conductance (MscL), a non-selective channel with a high conductance of ~3 nS that gates at tensions close to the membrane lytic tension.

It has been appreciated since the original discovery by C. Kung that the small subunit size (~130 to 160 residues) and the high conductance necessitate that MscL forms a homo-oligomeric channel. Over the past 20 years of study, the proposed oligomeric state of MscL has ranged from monomer to hexamer. Oligomeric state has been shown to vary between MscL homologues and is influenced by lipid/detergent environment. In this thesis, we report the creation of a chimera library to systematically survey the correlation between MscL sequence and oligomeric state to identify the sequence determinants of oligomeric state. Our results demonstrate that although there is no combination of sequences uniquely associated with a given oligomeric state (or mixture of oligomeric states), there are significant correlations. In the quest to characterize the oligomeric state of MscL, an exciting discovery was made about the dynamic nature of the MscL complex. We found that in detergent solution, under mild heating conditions (37 °C – 60 °C), subunits of MscL can exchange between complexes, and the dynamics of this process are sensitive to the protein sequence.

Extensive efforts were made to produce high diffraction quality crystals of MscL for the determination of a high resolution X-ray crystal structure of a full length channel. The surface entropy reduction strategy was applied to the design of S. aureus MscL variants and while the strategy appears to have improved the crystallizability of S. aureus MscL, unfortunately the diffraction qualities of these crystals were not significantly improved. MscL chimeras were also screened for crystallization in various solubilization detergents, but also failed to yield high quality crystals.

MscL is a fascinating protein and continues to serve as a model system for the study of the structural and functional properties of mechanosensitive channels. Further characterization of the MscL chimera library will offer more insight into the characteristics of the channel. Of particular interest are the functional characterization of the chimeras and the exploration of the physiological relevance of intercomplex subunit exchange.

Tão perto, tão longe: a vivência do enfermeiro na construção/desenvolvimento da relação mãe/recém-nascido na Unidade Terapia Intensiva Neonatal

Não há duvidas sobre a grandeza e intensidade que pode existir no relacionamento entre mãe e filho, porém, quando esse recém nascido é um bebê prematuro e/ou necessita de hospitalização em uma Unidade de Terapia Intensivo Neonatal (UTIN) pode haver um pode haver um choque, uma grande decepção, pois essa mãe não poderá interagir de forma plena com seu filho, não poderá amamentar e nem cuidar dele da forma habitual que se espera. Neste sentido, esse estudo propõe uma reflexão sobre a atuação do enfermeiro quanto à relação mãe/recém-nascido na UTIN. Assim sendo, tem-se como objeto A vivência do enfermeiro na construção/desenvolvimento da relação mãe/recém-nascido na UTIN. E como objetivo Compreender o significado da ação do enfermeiro na aproximação mãe/recém-nascido. Para o embasamento teórico foi necessário pensar sobre a prática do enfermeiro na UTIN, no que diz respeito a sua assistência, o processo de humanização neste ambiente e na inserção da família nos cuidados. Outro conceito fundamental discutido foi a interação, destacando o pensamento fenomenológico de Alfred Schutz. Estudo do tipo descritivo, desenvolvido com abordagem qualitativa e o referencial teórico-metodológico da fenomenologia. O cenário para sua realização foi a UTIN de um grande hospital da rede pública, localizado no subúrbio da cidade do Rio de Janeiro e foram sujeitos 16 enfermeiros lotados nesta unidade. A entrevista fenomenológica foi a técnica utilizada para captar as vivências profissionais e em seguida realizou-se a análise compreensiva tendo em vista a categorização. Como resultado chegou-se a 3 categorias do vivido; (1) ambientar as mães na UTIN: o começo da relação,(2) aproximar através do toque: usando os sentidos para se relacionar e (3) melhorar a relação entre mãe/recém-nascido: pensando no futuro. Além dessas categorias foi possível a apreensão do contexto vivencial das experiências dos enfermeiros no relacionamento com as mães de recém-nascidos na UTIN. Conclui-se que os enfermeiros que trabalham em UTIN têm a percepção de quão fundamental é promover a aproximação entre mãe e filho nesse ambiente. Contudo, essa ação ainda acontece de forma intuitiva, sem nenhum embasamento, e ainda muitas vezes é desprestigiada em detrimento da grande carga de trabalho deste setor, ou a gravidade do recém-nascido. É preciso que haja um maior engajamento por parte dos enfermeiros, em aprimorar as estratégias de aproximação entre mãe e recém-nascido, visando sempre um relacionamento mais saudável e harmonioso no futuro. Deste modo, o estudo contribui para enriquecer esta temática e despertar nos enfermeiros neonatologistas um olhar que compreenda não só os aspectos biológicos, mas também os psicossocias e torne, assim, a assistência ao recém nascido e sua família mais plena.

Toward Understanding Astrophysical Phenomena

Fast radio bursts (FRBs), a novel type of radio pulse, whose physics is not yet understood at all. Only a handful of FRBs had been detected when we started this project. Taking account of the scant observations, we put physical constraints on FRBs. We excluded proposals of a galactic origin for their extraordinarily high dispersion measures (DM), in particular stellar coronas and HII regions. Therefore our work supports an extragalactic origin for FRBs. We show that the resolved scattering tail of FRB 110220 is unlikely to be due to propagation through the intergalactic plasma. Instead the scattering is probably caused by the interstellar medium in the FRB's host galaxy, and indicates that this burst sits in the central region of that galaxy. Pulse durations of order $\ms$ constrain source sizes of FRBs implying enormous brightness temperatures and thus coherent emission. Electric fields near FRBs at cosmological distances would be so strong that they could accelerate free electrons from rest to relativistic energies in a single wave period. When we worked on FRBs, it was unclear whether they were genuine astronomical signals as distinct from `perytons', clearly terrestrial radio bursts, sharing some common properties with FRBs. Recently, in April 2015, astronomers discovered that perytons were emitted by microwave ovens. Radio chirps similar to FRBs were emitted when their doors opened while they were still heating. Evidence for the astronomical nature of FRBs has strengthened since our paper was published. Some bursts have been found to show linear and circular polarizations and Faraday rotation of the linear polarization has also been detected. I hope to resume working on FRBs in the near future. But after we completed our FRB paper, I decided to pause this project because of the lack of observational constraints.

The pulsar triple system, J0733+1715, has its orbital parameters fitted to high accuracy owing to the precise timing of the central $\ms$ pulsar. The two orbits are highly hierarchical, namely $P_{\mathrm{orb,1}}\ll P_{\mathrm{orb,2}}$, where 1 and 2 label the inner and outer white dwarf (WD) companions respectively. Moreover, their orbital planes almost coincide, providing a unique opportunity to study secular interaction associated purely with eccentricity beyond the solar system. Secular interaction only involves effect averaged over many orbits. Thus each companion can be represented by an elliptical wire with its mass distributed inversely proportional to its local orbital speed. Generally there exists a mutual torque, which vanishes only when their apsidal lines are parallel or anti-parallel. To maintain either mode, the eccentricity ratio, $e_1/e_2$, must be of the proper value, so that both apsidal lines precess together. For J0733+1715, $e_1\ll e_2$ for the parallel mode, while $e_1\gg e_2$ for the anti-parallel one. We show that the former precesses $\sim 10$ times slower than the latter. Currently the system is dominated by the parallel mode. Although only a little anti-parallel mode survives, both eccentricities especially $e_1$ oscillate on $\sim 10^3\yr$ timescale. Detectable changes would occur within $\sim 1\yr$. We demonstrate that the anti-parallel mode gets damped $\sim 10^4$ times faster than its parallel brother by any dissipative process diminishing $e_1$. If it is the tidal damping in the inner WD, we proceed to estimate its tidal quantity parameter ($Q$) to be $\sim 10^6$, which was poorly constrained by observations. However, tidal damping may also happen during the preceding low-mass X-ray binary (LMXB) phase or hydrogen thermal nuclear flashes. But, in both cases, the inner companion fills its Roche lobe and probably suffers mass/angular momentum loss, which might cause $e_1$ to grow rather than decay.

Several pairs of solar system satellites occupy mean motion resonances (MMRs). We divide these into two groups according to their proximity to exact resonance. Proximity is measured by the existence of a separatrix in phase space. MMRs between Io-Europa, Europa-Ganymede and Enceladus-Dione are too distant from exact resonance for a separatrix to appear. A separatrix is present only in the phase spaces of the Mimas-Tethys and Titan-Hyperion MMRs and their resonant arguments are the only ones to exhibit substantial librations. When a separatrix is present, tidal damping of eccentricity or inclination excites overstable librations that can lead to passage through resonance on the damping timescale. However, after investigation, we conclude that the librations in the Mimas-Tethys and Titan-Hyperion MMRs are fossils and do not result from overstability.

Rubble piles are common in the solar system. Monolithic elements touch their neighbors in small localized areas. Voids occupy a significant fraction of the volume. In a fluid-free environment, heat cannot conduct through voids; only radiation can transfer energy across them. We model the effective thermal conductivity of a rubble pile and show that it is proportional the square root of the pressure, $P$, for $P\leq \epsy^3\mu$ where $\epsy$ is the material's yield strain and $\mu$ its shear modulus. Our model provides an excellent fit to the depth dependence of the thermal conductivity in the top $140\,\mathrm{cm}$ of the lunar regolith. It also offers an explanation for the low thermal inertias of rocky asteroids and icy satellites. Lastly, we discuss how rubble piles slow down the cooling of small bodies such as asteroids.

Electromagnetic (EM) follow-up observations of gravitational wave (GW) events will help shed light on the nature of the sources, and more can be learned if the EM follow-ups can start as soon as the GW event becomes observable. In this paper, we propose a computationally efficient time-domain algorithm capable of detecting gravitational waves (GWs) from coalescing binaries of compact objects with nearly zero time delay. In case when the signal is strong enough, our algorithm also has the flexibility to trigger EM observation {\it before} the merger. The key to the efficiency of our algorithm arises from the use of chains of so-called Infinite Impulse Response (IIR) filters, which filter time-series data recursively. Computational cost is further reduced by a template interpolation technique that requires filtering to be done only for a much coarser template bank than otherwise required to sufficiently recover optimal signal-to-noise ratio. Towards future detectors with sensitivity extending to lower frequencies, our algorithm's computational cost is shown to increase rather insignificantly compared to the conventional time-domain correlation method. Moreover, at latencies of less than hundreds to thousands of seconds, this method is expected to be computationally more efficient than the straightforward frequency-domain method.

The Molecular Basis of Lysine Acetylation: Addition, Removal, and Recognition

Acetyltransferases and deacetylases catalyze the addition and removal, respectively, of acetyl groups to the epsilon-amino group of protein lysine residues. This modification can affect the function of a protein through several means, including the recruitment of specific binding partners called acetyl-lysine readers. Acetyltransferases, deacetylases, and acetyl-lysine readers have emerged as crucial regulators of biological processes and prominent targets for the treatment of human disease. This work describes a combination of structural, biochemical, biophysical, cell-biological, and organismal studies undertaken on a set of proteins that cumulatively include all steps of the acetylation process: the acetyltransferase MEC-17, the deacetylase SIRT1, and the acetyl-lysine reader DPF2. Tubulin acetylation by MEC-17 is associated with stable, long-lived microtubule structures. We determined the crystal structure of the catalytic domain of human MEC-17 in complex with the cofactor acetyl-CoA. The structure in combination with an extensive enzymatic analysis of MEC-17 mutants identified residues for cofactor and substrate recognition and activity. A large, evolutionarily conserved hydrophobic surface patch distal to the active site was shown to be necessary for catalysis, suggesting that specificity is achieved by interactions with the alpha-tubulin substrate that extend outside of the modified surface loop. Experiments in C. elegans showed that while MEC-17 is required for touch sensitivity, MEC-17 enzymatic activity is dispensible for this behavior. SIRT1 deacetylates a wide range of substrates, including p53, NF-kappaB, FOXO transcription factors, and PGC-1-alpha, with roles in cellular processes ranging from energy metabolism to cell survival. SIRT1 activity is uniquely controlled by a C-terminal regulatory segment (CTR). Here we present crystal structures of the catalytic domain of human SIRT1 in complex with the CTR in an apo form and in complex with a cofactor and a pseudo-substrate peptide. The catalytic domain adopts the canonical sirtuin fold. The CTR forms a beta-hairpin structure that complements the beta-sheet of the NAD^+-binding domain, covering an essentially invariant, hydrophobic surface. A comparison of the apo and cofactor bound structures revealed conformational changes throughout catalysis, including a rotation of a smaller subdomain with respect to the larger NAD^+-binding subdomain. A biochemical analysis identified key residues in the active site, an inhibitory role for the CTR, and distinct structural features of the CTR that mediate binding and inhibition of the SIRT1 catalytic domain. DPF2 represses myeloid differentiation in acute myelogenous leukemia. Finally, we solved the crystal structure of the tandem PHD domain of human DPF2. We showed that DPF2 preferentially binds H3 tail peptides acetylated at Lys14, and binds H4 tail peptides with no preference for acetylation state. Through a structural and mutational analysis we identify the molecular basis of histone recognition. We propose a model for the role of DPF2 in AML and identify the DPF2 tandem PHD finger domain as a promising novel target for anti-leukemia therapeutics.

A assistência às pessoas vivendo com HIV/AIDS: aprendendo a cuidar do vírus ou da pessoa?

O presente estudo descreve e analisa o aprendizado dos médicos residentes para a prática da assistência às pessoas que vivem com HIV/Aids desenvolvida em um serviço de Doenças Infecciosas e Parasitárias de um Hospital Universitário no Estado do Rio de Janeiro. É uma pesquisa de cunho etnográfico, com a observação do processo de treinamento em consulta em ato da atenção, realizada por médico residente, sob supervisão de staffs do serviço. Os aspectos multicausais da Aids suscitam demandas tanto nos pacientes quanto nos profissionais de saúde envolvidos na assistência a essas pessoas. O processo de ensino/aprendizado na medicina prioriza a doença, relegando a segundo plano, o doente com suas questões subjetivas, sociais, culturais e econômicas. Entretanto, ao lidarem com estas pessoas, os médicos entram em contato com aspectos objetivos e subjetivos do processo de adoecimento individual. É neste momento, que fica evidente as lacunas deixadas neste processo de aprendizado. Paulatinamente, os médicos vão aprendendo a cuidar do vírus e seus efeitos. Eventualmente aprendem a cuidar também da pessoa. Para o alcance de uma atenção integral e humanizada ainda é necessário ampliar e aprofundar as reformulações no processo de ensino/aprendizagem dos médicos. Mudanças essas que permitam o aprendizado de cuidar bem tanto da carga viral, do CD4 e dos anti-retrovirais quanto da pessoa que porta o vírus.