How Beliefs about HIV Status Affect Risky Behaviors: Evidence from Malawi, Second Version

This paper examines whether and to what extent changes in beliefs about own HIV status induce changes in risky sexual behavior using data from married males living in three regions of Malawi. Risky behavior is measured as the propensity to engage in extramarital affairs. The empirical analysis is based on panel surveys for years 2006 and 2008 from the Malawi Diffusion and Ideational Change Project (MDICP), which contain detailed information on beliefs about HIV status and on sexual behaviors. Many individuals change their beliefs over time, because of opportunities to get tested for HIV and informational campaigns. We estimate the effect of belief revisions on the propensity to engage in extra-marital affairs using a panel data estimator developed by Arellano and Carrasco (2003), which accommodates unobserved heterogeneity as well as belief endogeneity arising from the dependence of current beliefs on lagged behaviors. We find that downward revisions in the belief of being HIV positive lead to an increased propensity to engage in extra-marital affairs and upward revisions to a decreased propensity. The estimates are shown to be robust to underreporting of affairs. Using our estimates and a standard epidemeological model of disease transmission, we find that increasing the responsiveness of beliefs to test results would reduce the HIV transmission rate as infected individuals reduce sexual behavior and decrease the likelihood that uninfected persons have contact with an HIV-positive person.AIDS, Malawi, Beliefs

How Beliefs About HIV Status affect Risky Behaviors: Evidence From Malawi, Second Version

This paper examines how beliefs about own HIV status affect sexual behavior. Risky behavior is measured as the propensity to engage in extramarital affairs or not use condoms. The empirical analysis is based on 2004 and 2006 data from the Malawi Diffusion and Ideational Change Project. Controlling for endogeneity between beliefs and risk-taking, we find that downward revisions in the belief of being HIV positive lead to a lower propensity to engage in extramarital affairs but have no effect on condom use. We show that the estimates provide a lower bound when there is measurement error in reported extra-marital affairs.Beliefs,AIDS,Malawi

How Beliefs about HIV Status Affect Risky Behaviors: Evidence from Malawi, Fifth Version

This paper examines how beliefs about own HIV status affect decisions to engage in risky sexual behavior using data on married males living in Malawi. Risky behavior is measured as the propensity to engage in extramarital affairs. The empirical analysis is based on panel surveys for years 2006 and 2008 from the Malawi Diffusion and Ideational Change Project (MDICP). Beliefs vary significantly over time in the data, in part because of HIV testing and informational campaigns. We estimate the effect of beliefs about own HIV status on risky behavior using a panel data estimator developed by Arellano and Carrasco (2003), which accommodates unobserved heterogeneity as well as belief endogeneity arising from the dependence of current beliefs on lagged behaviors. We find that beliefs are an important determinant of risky behavior, with downward revisions in the belief of being HIV positive increasing risky behavior and upward revisions decreasing it. We modify Arellano and Carrasco’s (2003) estimator to allow for underreporting of affairs and find the estimates to be relatively robust to underreporting. Using our estimates and a prototypical epidemiological model of disease transmission, we show that making individuals better informed about their HIV status, either by increasing the credibility of test results and/or increasing access to testing, would on net reduce the HIV transmission rate.Beliefs, Malawi, HIV

How Beliefs about HIV Status Affect Risky Behaviors: Evidence from Malawi, Sixth Version

This paper examines how beliefs about own HIV status affect decisions to engage in risky sexual behavior (as measured by extramarital affairs) and analyzes the potential for interventions that influence beliefs, such as HIV testing and informational campaigns, to reduce transmission rates. The empirical analysis is based on a panel survey of married males for years 2006 and 2008 from the Malawi Diffusion and Ideational Change Project (MDICP). In the data, beliefs about HIV status vary significantly geographically and over time, in part because of newly available testing opportunities and because of cultural differences. We estimate the effect of beliefs on risky behavior using Arellano and Carrasco’s (2003) semiparametric panel data estimator, which accommodates unobserved heterogeneity and belief endogeneity. Results show that changes in the belief of being HIV positive induce changes in risky behavior. Downward revisions in beliefs increase risky behavior and upward revisions decrease it. We modify Arellano and Carrasco’s (2003) estimator to allow for underreporting of extramarital affairs and find the estimates to be robust. Using the estimates and a prototypical epidemiological model of disease transmission, we show that better informing people about their HIV status on net reduces the population HIV transmission rate.Malawi,HIV,beliefs

O desenvolvimento pesqueiro mundial, a variabilidade dos recursos e a gestão

FAO regularly releases studies on the state of fish resources exploitation (The state of world fisheries and aquaculture)and the development of fisheries by geographic areas. The 1983 and 1985 editions provided interesting discussions on fisheries development trends in the world: the majority of sea-facing countries adopted legislation that extends the national jurisdiction on the waters off their coasts (usually indicated within 200 miles) and establishes exclusive economic zones (EEZs). The huge fluctuations in the abundance of some fish stocks are obstacles to fisheries development. This issue, as well as the need to improve research activities and management of fish stocks is also analyzed in this work. The author highlighted the situation of fisheries in the Western Indian Ocean, with particular attention to tuna fisheries and to inland water resources of Mozambique

Growth of the buccaneer anchovy Encrasicholina punctifer off Mozambique, based on samples collected in research surveys

Growth of Encrasicholina punctifer (Engraulididae) is estimated, based on samples obtained during five surveys on Sofala Bank (central Mozambique). The estimated values of the von Bertalanffy growth function, TL∞=12 cm and K=2.0 yearˉ¹ are compared with results of growth studies elsewhere in the Indo-Pacific region, based mainly on the index Φ=log(sub)10 K+2*log(sub)10L∞ assumed to be constant within species. This comparison is rendered difficult by the uncertain taxonomical status of stolephorid anchovies

Hadrons in AdS/QCD models

We discuss applications of gauge/gravity duality to describe the spectrum of light hadrons. We compare two particular 5-dimensional approaches: a model with an infrared deformed Anti-de Sitter metric and another one based on a dynamical AdS/QCD framework with back-reacted geometry in a dilaton/gravity background. The models break softly the scale invariance in the infrared region and allow mass gap for the field excitations in the gravity description, while keeping the conformal property of the metric close to the four-dimensional boundary. The models provide linear Regge trajectories for light mesons, associated with specially designed infrared gravity properties. We also review the results for the decay widths of the f0's into two pions, as overlap integrals between mesonic string amplitudes, which are in qualitative agreement with data

A Method to Discriminate Species From Hydroacoustic Fish Sampling Systems.

Samples of species and size composition obtained by trawling were matched with the corresponding echo-distributions from two hydroacoustic and trawl surveys in the western Indian Ocean, off Mozambique, and in two surveys in the northern Gulf of Mexico. In the Mozambique surveys, a Simrad EY-M echosounder was used and the data was analyzed by applying the Craig & Forbes algorithm. In the Gulf of Mexico surveys, a BioSonics Dual-beam System (Model 102 echosounder, ESP echo-integrator, and ESP dual-beam processor) was used. The results obtained show that, provided that a particular hydroacoustic and trawl sample yielded a stable size-distribution of the fish species present in the area and a stable TS-distribution of individual echoes, the match of the mean values of normal components of each distribution is achieved. The match was sought by calculating the beta coefficient from the simplified Love\u27s equation (TS = 20 x log10 Length -- beta) and comparing the obtained value with published results for similar species. A number of individual matches for the same species was then used to estimate the equations relating fish size and target strength for individual species in these multispecies ecosystems. This was achieved by testing the fit of the individual data pairs to linear regression models, both in the form of the simplified Love\u27s equation, through a restricted regression with slope = 20, and on its generalized form (TS = m x log10 Length -- beta.) The models produced for the different species were also tested for differences among them and were found to be significantly different. Equations relating target strength and fish size were adopted as representative for three species from the northern Gulf of Mexico, the round herring, Etrumeus teres, the Gulf butterfish, Peprilus burti, and the chub mackerel, Scomber japonicus, and for one species from the western Indian Ocean, the Indian pellona, Pellona ditchella . In addition, one observation on the relationship between target strength and length of the round herring from Mozambique was found to fit the model adopted for the same species in the Gulf of Mexico

Outros recursos marinhos

The paper describes marine fish resources living in Mozambican waters. Resource data on distribution areas, reproduction, age, growth and stock size are described. Actual price of the commercially exploited stocks are also given. The problems involving the assessment of catch areas are discussed