Quantifying the Inefficiency of the US Social Security System

We quantify the inefficiency of the retirement component of the US social security system within a model where agents receive idiosyncratic labor-productivity shocks that are privately observedsocial security, efficient allocations, idiosyncratic shocks

You never surf alone. Ubiquitous tracking of users' browsing habits

In the early age of the internet users enjoyed a large level of anonymity. At the time web pages were just hypertext documents; almost no personalisation of the user experience was o ered. The Web today has evolved as a world wide distributed system following specific architectural paradigms. On the web now, an enormous quantity of user generated data is shared and consumed by a network of applications and services, reasoning upon users expressed preferences and their social and physical connections. Advertising networks follow users' browsing habits while they surf the web, continuously collecting their traces and surfing patterns. We analyse how users tracking happens on the web by measuring their online footprint and estimating how quickly advertising networks are able to pro le users by their browsing habits

AIROscope stellar acquisition

The acquisition system which operates in conjunction with a balloon-borne TV system, boresighted to a telescope is described. It has two main functions, a star field monitor and an offset star tracker. The design of the system was strongly influenced by the TV camera, which uses the same interlaced scanning system as is employed in commercial television broadcasting. To reduce power and bandwidth requirements, the star field information transmitted in our system consists only of the horizontal and vertical coordinates of each star and its brightness. As a star field monitor the system provides video thresholding, camera blemish suppression, coordinate digitization in 3 axes, circuity to recognize as single star the dispersed video signals resulting from one star overlapping adjacent scanning lines and storage of all signals for readout by the telemetry at appropriate times

A qualitative study of older adults' perspectives on initiating exercise and mindfulness practice.

BackgroundMindfulness practice and exercise are ways by which older adults can improve and maintain their physical, emotional and cognitive health.MethodsThis single-site qualitative study gathered insights of older adults' perceptions about initiating and maintaining mindfulness and exercise practices. We carried out focus groups with 41 adults aged 65-85 who had recently initiated Mindfulness Based Stress Reduction (MBSR), structured exercise, or their combination as part of participation in a clinical trial. We used a semi-structured interview to ask them open-ended questions regarding the benefits, barriers and facilitators of participating in mindfulness and/or exercise interventions. The interview also included questions regarding translation of these practices into community settings as well as the long-term maintenance potential of these practices.ResultsOlder adults indicated that the mindfulness training increased their awareness and self-reflection and fostered a more self-accepting attitude. Furthermore, they improved their self-care habits and reported having better familial and social relationships. The main barrier for both the exercise and Mindfulness group was time management. The social benefits and sense of community were some of the primary motivators for older adults in the exercise and/or MBSR interventions. However, the research on how to motivate older adults to initiate healthy behavioral changes also needs to be answered. The benefits of exercise and MBSR are a motivation in and of themselves, as indicated by some of the participants.ConclusionsThis study indicates that mindfulness training and exercise can serve as tools to cultivate important health lifestyle qualities among older adults, who are in the midst of mental, social, emotional and physical change. If it were not for the purpose of the research or the incentives provided by the research team, these older adults may have never started the healthy behavioral changes. From the responses, this may indicate that older adults may need more incentives to begin and maintain behavioral changes other than for their own health benefit

Reduction of a metapopulation genetic model to an effective one island model

We explore a model of metapopulation genetics which is based on a more ecologically motivated approach than is frequently used in population genetics. The size of the population is regulated by competition between individuals, rather than by artificially imposing a fixed population size. The increased complexity of the model is managed by employing techniques often used in the physical sciences, namely exploiting time-scale separation to eliminate fast variables and then constructing an effective model from the slow modes. Remarkably, an initial model with 2$\mathcal{D}$ variables, where $\mathcal{D}$ is the number of islands in the metapopulation, can be reduced to a model with a single variable. We analyze this effective model and show that the predictions for the probability of fixation of the alleles and the mean time to fixation agree well with those found from numerical simulations of the original model.Comment: 16 pages, 4 figures. Supplementary material: 22 pages, 3 figure

Atividade diurna de adultos de Diabrótica speciosa na cultura do milho e de cerotoma arcuatus na cultura da soja.

Neste documento são apresentadas importantes informações sobre o ritmo de atividade diurna de adultos de D. speciosa, na cultura do milho, e de C. arcuatus na cultura da soja. Assim, as informações contidas neste trabalho são de grande valia, pois podem auxiliar na definição de táticas para o manejo dessas pragas.bitstream/item/38187/1/DOC200464.pd

Symmetry breaking in MAST plasma turbulence due to toroidal flow shear

The flow shear associated with the differential toroidal rotation of tokamak plasmas breaks an underlying symmetry of the turbulent fluctuations imposed by the up-down symmetry of the magnetic equilibrium. Using experimental Beam-Emission-Spectroscopy (BES) measurements and gyrokinetic simulations, this symmetry breaking in ion-scale turbulence in MAST is shown to manifest itself as a tilt of the spatial correlation function and a finite skew in the distribution of the fluctuating density field. The tilt is a statistical expression of the "shearing" of the turbulent structures by the mean flow. The skewness of the distribution is related to the emergence of long-lived density structures in sheared, near-marginal plasma turbulence. The extent to which these effects are pronounced is argued (with the aid of the simulations) to depend on the distance from the nonlinear stability threshold. Away from the threshold, the symmetry is effectively restored

Gene deficiency in activating Fcγ receptors influences the macrophage phenotypic balance and reduces atherosclerosis in mice

Immunity contributes to arterial inflammation during atherosclerosis. Oxidized low-density lipoproteins induce an autoimmune response characterized by specific antibodies and immune complexes in atherosclerotic patients. We hypothesize that specific Fcγ receptors for IgG constant region participate in atherogenesis by regulating the inflammatory state of lesional macrophages. In vivo we examined the role of activating Fcγ receptors in atherosclerosis progression using bone marrow transplantation from mice deficient in γ-chain (the common signaling subunit of activating Fcγ receptors) to hyperlipidemic mice. Hematopoietic deficiency of Fcγ receptors significantly reduced atherosclerotic lesion size, which was associated with decreased number of macrophages and T lymphocytes, and increased T regulatory cell function. Lesions of Fcγ receptor deficient mice exhibited increased plaque stability, as evidenced by higher collagen and smooth muscle cell content and decreased apoptosis. These effects were independent of changes in serum lipids and antibody response to oxidized low-density lipoproteins. Activating Fcγ receptor deficiency reduced pro-inflammatory gene expression, nuclear factor-κB activity, and M1 macrophages at the lesion site, while increasing anti-inflammatory genes and M2 macrophages. The decreased inflammation in the lesions was mirrored by a reduced number of classical inflammatory monocytes in blood. In vitro, lack of activating Fcγ receptors attenuated foam cell formation, oxidative stress and pro-inflammatory gene expression, and increased M2-associated genes in murine macrophages. Our study demonstrates that activating Fcγ receptors influence the macrophage phenotypic balance in the artery wall of atherosclerotic mice and suggests that modulation of Fcγ receptor-mediated inflammatory responses could effectively suppress atherosclerosis