Aplicación del sistema LISREL para el análisis de un modelo de comportamiento sexual de prevención en ADVP

Se aplica el Sistema LISREL, para el análisis de un modelo de comportamiento sexual de prevención del contagio con el virus de inmunodeficiencia humana (VIH) en una muestra de 63 adictos a las drogas por vía parental (ADVP) en tratamiento. Se incluyen en el modelo variables que habitualmente son evaluadas y registradas en los centros de rehabilitación y cuya influencia ha sido demostrada en estudios anteriores. En líneas generales, los resultados corroboran los datos aportados por otros autores respecto a que los hombres y los sujetos VIH+ son, en general, más preventivos en sus relaciones sexuales

Desenmascarar el pensamiento heteronormativo de la educación en la diversidad afectivo-sexual: Guías didácticas en Cataluña: Una óptica psicosocial crítica

El projecte fa una anàlisi dels programes educatius o guies didàctiques dirigides a treballar la diversitat afectiva i sexual què s’han desenvolupat en els centres de primària i secundària a Catalunya fins al curs 2006-2007

L' atur de llarga durada de les dones majors de 45 anys a Catalunya: una anàlisi exploratòria tenint en compte la classe social i la divisió sexual del treball

This article provides an in-depth study of long-term female unemployment in Catalonia.Long-term unemployment statistics reveal which social groups are most likely to experience difficulty re-entering the labour market. In this case, we found that women are mainly affected by this type of labour exclusion, in particular poorly qualified, working-class women who are aged over 45 and with family responsibilities.The article aims to explore how the overlapping of factors such as gender, age, social class, origin and the division of work based on gender are related to long-term female unemployment. Moreover, we were able to detect which conceptual tools provide us with the production/reproduction paradigm so as to be able to analyse the future of female unemployment. The methodology we used combines quantitative and qualitative approaches. On the one hand, the analysis of secondary statistical data focusing on Catalonia is useful in understanding the situation from a macro-social perspective. On the other hand, an exploratory discussion group enables us to investigate social imaginary practises among unemployed working class women aged over 45. This discussion group was held in Igualada -capital of the Anoia region - an area of Catalonia deeply affected by unemployment in the current economic crisis.

Prevención de la transmisión sexual del VIH en adolescentes

En una muestra de 119 estudiantes de cuarto de Educación Secundaria Obligatoria (ESO) y primerode Bachillerato (52,6% mujeres) se analizan los conocimientos sobre la prevención de latransmisión sexual del virus del sida, las expectativas de resultados y de autoeficacia respecto a losmétodos preventivos y el tipo de prevención utilizada durante la última relación sexual. Para evitarlas respuestas inducidas respecto a los comportamientos preventivos se emplea un formato de preguntaabierta. Los resultados muestran que sólo el 23,5% de los estudiantes han dado dos respuestastotalmente correctas sobre estrategias consideradas eficaces en la prevención sexual del VIH:uso del preservativo y abstinencia (por este orden). El 70,5% valoran totalmente o muy eficaz elpreservativo para evitar la transmisión sexual del VIH y el 95% de los que dan la segunda respuestajuzgan totalmente eficaz la práctica de la abstinencia con la misma finalidad. En el caso del preservativose sienten totalmente o muy capaces de usarlo el 64,3%, mientras que cuando se trata de laabstinencia sólo se perciben con esa competencia el 20%. Por lo que se refiere al uso autoinformadode métodos preventivos en la última relación, por parte de los 29 estudiantes que tuvieronactividad sexual durante el mes anterior, se observa que 21 de ellos emplearon el preservativo, dosla píldora anticonceptiva, otros dos no precisan el tipo de precaución y el resto no tomó ninguna.Tanto el reducido nivel de conocimientos sobre prevención, como la baja percepción de autoeficaciapara mantenerse abstinentes, nos alertan sobre la necesidad de hacer un mayor esfuerzo de informaciónpara eliminar creencias equivocadas, como por ejemplo: sobre la pretendida eficacia protectorade tener relaciones sexuales con una pareja estable o conocida. Así mismo, conviene insistiren el uso del preservativo como anticonceptivo de elección entre los adolescentes

How did the Financial Crisis affect the Real Interest Rate Dynamics in Europe?

We investigate the effects of the financial crisis on the stationarity of real interest rates in the Euro Area. We use a new unit root test developed by Peseran et al. (2013) that allows for multiple unobserved factors in a panel set up. Our results suggest that while short-term and long-term real interest rates were stationary before the financial crisis, they became nonstationary during the crisis period likely due to persistent risk that characterized financial markets during that time. JEL codes: E43, C23. Keywords: Real interest rates, Euro Area, financial crisis, panel unit root tests, cross-sectional dependence.

The Cornella Health Interview Survey Follow-Up (CHIS.FU) Study: design, methods, and response rate

Background: The aim of this report is to describe the main characteristics of the design, including response rates, of the Cornella Health Interview Survey Follow-up Study. Methods: The original cohort consisted of 2,500 subjects (1,263 women and 1,237 men) interviewed as part of the 1994 Cornella Health Interview Study. A record linkage to update the address and vital status of the cohort members was carried out using, first a deterministic method, and secondly a probabilistic one, based on each subject's first name and surnames. Subsequently, we attempted to locate the cohort members to conduct the phone follow-up interviews. A pilot study was carried out to test the overall feasibility and to modify some procedures before the field work began. Results: After record linkage, 2,468 (98.7%) subjects were successfully traced. Of these, 91 (3.6%) were deceased, 259 (10.3%) had moved to other towns, and 50 (2.0%) had neither renewed their last municipal census documents nor declared having moved. After using different strategies to track and to retain cohort members, we traced 92% of the CHIS participants. From them, 1,605 subjects answered the follow-up questionnaire. Conclusion: The computerized record linkage maximized the success of the follow-up that was carried out 7 years after the baseline interview. The pilot study was useful to increase the efficiency in tracing and interviewing the respondents.

Capacity-approaching rate function for layered multiantenna architectures

The simultaneous use of multiple transmit and receive antennas can unleash very large capacity increases in rich multipath environments. Although such capacities can be approached by layered multi-antenna architectures with per-antenna rate control, the need for short-term feedback arises as a potential impediment, in particular as the number of antennas—and thus the number of rates to be controlled—increases. What we show, however, is that the need for short-term feedback in fact vanishes as the number of antennas and/or the diversity order increases. Specifically, the rate supported by each transmit antenna becomes deterministic and a sole function of the signal-to-noise, the ratio of transmit and receive antennas, and the decoding order, all of which are either fixed or slowly varying. More generally, we illustrate -through this specific derivation— the relevance of some established random CDMA results to the single-user multi-antenna problem.

The neuronal basis of attention: rate versus synchronization modulation

Extensive theoretical and experimental work on the neuronal correlates of visual attention raises two hypotheses about the underlying mechanisms. The first hypothesis, named biased competition, originates from experimental single-cell recordings that have shown that attention upmodulates the firing rates of the neurons encoding the attended features and downregulates the firing rates of the neurons encoding the unattended features. Furthermore, attentional modulation of firing rates increases along the visual pathway. The other, newer hypothesis assigns synchronization a crucial role in the attentional process. It stems from experiments that have shown that attention modulates gamma-frequency synchronization. In this paper, we study the coexistence of the two phenomena using a theoretical framework. We find that the two effects can vary independently of each other and across layers. Therefore, the two phenomena are not concomitant. However, we show that there is an advantage in the processing of information if rate modulation is accompanied by gamma modulation, namely that reaction times are shorter, implying behavioral relevance for gamma synchronization.

On high-rate full-diversity 2x2 space-time codes with low-complexity optimum detection

The 2×2 MIMO profiles included in Mobile WiMAX specifications are Alamouti’s space-time code (STC) fortransmit diversity and spatial multiplexing (SM). The former hasfull diversity and the latter has full rate, but neither of them hasboth of these desired features. An alternative 2×2 STC, which is both full rate and full diversity, is the Golden code. It is the best known 2×2 STC, but it has a high decoding complexity. Recently, the attention was turned to the decoder complexity, this issue wasincluded in the STC design criteria, and different STCs wereproposed. In this paper, we first present a full-rate full-diversity2×2 STC design leading to substantially lower complexity ofthe optimum detector compared to the Golden code with only a slight performance loss. We provide the general optimized form of this STC and show that this scheme achieves the diversitymultiplexing frontier for square QAM signal constellations. Then, we present a variant of the proposed STC, which provides a further decrease in the detection complexity with a rate reduction of 25% and show that this provides an interesting trade-off between the Alamouti scheme and SM.

Per-antenna rate and power control for MIMO layered architectures in the low- and high-power regimes

In a MIMO layered architecture, several codewordsare transmitted from a multiplicity of antennas. Although thespectral efficiency is maximized if the rates of these codewordsare separately controlled, the feedback rate within the linkadaptation loop is reduced if they are constrained to be identical.This poses a direct tradeoff between performance andfeedback overhead. This paper provides analytical expressionsthat quantify the difference in spectral efficiency between bothapproaches for arbitrary numbers of antennas. Specifically, thecharacterization takes place in the realm of the low- and highpowerregimes via expansions that are shown to have a widerange of validity.In addition, the possibility of adjusting the transmit powerof each codeword individually is considered as an alternative tothe separate control of their rates. Power allocation, however,turns out to be inferior to rate control within the context of thisproblem.

A comparison of full-rate full-diversity 2x2 space-time codes for WiMAX systems

Multiple-input multiple-output (MIMO) techniques have become an essential part of broadband wireless communications systems. For example, the recently developed IEEE 802.16e specifications for broadband wireless access include three MIMOprofiles employing 2×2 space-time codes (STCs), and two of these MIMO schemes are mandatory on the downlink of Mobile WiMAX systems. One of these has full rate, and the other has full diversity, but neither of them has both of the desired features. The third profile, namely, Matrix C, which is not mandatory, is both a full rate and a full diversity code, but it has a high decoder complexity. Recently, the attention was turned to the decodercomplexity issue and including this in the design criteria, several full-rate STCs were proposed as alternatives to Matrix C. In this paper, we review these different alternatives and compare them to Matrix C in terms of performances and the correspondingreceiver complexities.

A qui li dic? : la detecció de l’abús sexual infantil i el traspàs d’informació entre professionals

Aquest treball s'estructura en una primera part de fonamentació teòrica. El procediment que s'ha seguit ha estat la recerca bibliogràfica. Es basa en els aspectes tècnics a tenir en compte per la detecció de l' Abusos Sexuals Infantils (ASI), la ubicació dels Serveis Bàsics d'Atenció Social (SBAS) dins el sistema català de serveis socials, el marc jurídic dels drets i de la protecció a la infància i l'adolescència així com de qüestions relatives al tractament de dades, de la confidencialitat de les informacions de què disposem els/les professionals, l'obligació de secret, complementat amb la deontologia professional, que ens pot orientar a l'hora de prendre les decisions més adequades a la nostra praxi. La segona part del treball és empírica. El procediment ha estat portar a terme un grup de reflexió ètica amb professionals del Consorci de Benestar Social del Pla de l'Estany-Banyoles. Partint de casos pràctics de sospita d'ASI, les persones participants han concretat els principals problemes (alguns dels quals relacionats amb l'ètica aplicada) davant els quals s'han trobat a la fase de detecció/intervenció. Les aportacions extretes de les diferents sessions en les quals es van treballar part dels objectius d'aquesta recerca ens permeten concretar la realitat i una primera deliberació sobre quina podria ser la bona pràctica general. La tercera part utilitza la fonamentació teòrica i els material del treball de camp per presentar la reflexió final que pretén donar resposta als objectius plantejats en aquesta recerca

Option pricing under stochastic volatility and stochastic interest rate in the Spanish case

Among the underlying assumptions of the Black-Scholes option pricingmodel, those of a fixed volatility of the underlying asset and of aconstantshort-term riskless interest rate, cause the largest empirical biases. Onlyrecently has attention been paid to the simultaneous effects of thestochasticnature of both variables on the pricing of options. This paper has tried toestimate the effects of a stochastic volatility and a stochastic interestrate inthe Spanish option market. A discrete approach was used. Symmetricand asymmetricGARCH models were tried. The presence of in-the-mean and seasonalityeffectswas allowed. The stochastic processes of the MIBOR90, a Spanishshort-terminterest rate, from March 19, 1990 to May 31, 1994 and of the volatilityofthe returns of the most important Spanish stock index (IBEX-35) fromOctober1, 1987 to January 20, 1994, were estimated. These estimators wereused onpricing Call options on the stock index, from November 30, 1993 to May30, 1994.Hull-White and Amin-Ng pricing formulas were used. These prices werecomparedwith actual prices and with those derived from the Black-Scholesformula,trying to detect the biases reported previously in the literature. Whereasthe conditional variance of the MIBOR90 interest rate seemed to be freeofARCH effects, an asymmetric GARCH with in-the-mean and seasonalityeffectsand some evidence of persistence in variance (IEGARCH(1,2)-M-S) wasfoundto be the model that best represent the behavior of the stochasticvolatilityof the IBEX-35 stock returns. All the biases reported previously in theliterature were found. All the formulas overpriced the options inNear-the-Moneycase and underpriced the options otherwise. Furthermore, in most optiontrading, Black-Scholes overpriced the options and, because of thetime-to-maturityeffect, implied volatility computed from the Black-Scholes formula,underestimatedthe actual volatility.