Extinction techniques and impact on dust property determination

The near infrared extinction powerlaw index ($\beta$) and its uncertainty is derived from three different techniques based on star counts, colour excess and a combination of them. We have applied these methods to 2MASS data to determine maps of $\beta$ and near infrared extinction of the small cloud IC 1396 W. The combination of star counts and colour excess results in the most reliable method to determine $\beta$. It is found that the use of the correct $\beta$-map to transform colour excess values into extinction is fundamental for column density profile analysis of clouds. We describe how artificial photometric data, based on the model of stellar population synthesis of the Galaxy (Robin et al. 2003), can be used to estimate uncertainties and derive systematic effects of the extinction methods presented here. We find that all colour excess based extinction determination methods are subject to small but systematic offsets, which do not affect the star counting technique. These offsets occur since stars seen through a cloud do not represent the same population as stars in an extinction free control field.Comment: 10 pages, 9 figures, 1 table, accepted for publication in MNRA

A large scale extinction map of the Galactic Anticenter from 2MASS

We present a 127deg x 63deg extinction map of the Anticenter of the Galaxy, based on and colour excess maps from 2MASS. This 8001 square degree map with a resolution of 4 arcminutes is provided as online material. The colour excess ratio / is used to determine the power law index of the reddening law (\beta) for individual regions contained in the area (e.g. Orion, Perseus, Taurus, Auriga, Monoceros, Camelopardalis, Cassiopeia). On average we find a dominant value of \beta=1.8+-0.2 for the individual clouds, in agreement with the canonical value for the interstellar medium. We also show that there is an internal scatter of \beta values in these regions, and that in some areas more than one dominant \beta value is present. This indicates large scale variations in the dust properties. The analysis of the A_V values within individual regions shows a change in the slope of the column density distribution with distance. This can either be attributed to a change in the governing physical processes in molecular clouds on spatial scales of about 1pc or an A_V dilution with distance in our map.Comment: 18 pages, 29 Figures, 1 Table, Accepted for publication by MNRAS, A version with higher resolution figures can be found at http://astro.kent.ac.uk/~df

A detailed two-dimensional stellar population study of M32

We present Two-Dimensional Spectroscopy of the 9x12 arcsec^2 central region of M32 obtained with the 2D_FIS fibre spectrograph installed at the William Herschel Telescope. From these spectra line strength maps have been reconstructed for about 20 absorption lines, mostly belonging to the Lick system. We find good agreement with long-slit line strength profiles in the literature. In contrast with previous studies, indices were azimuthally averaged along continuum isophotes of M32. A remarkable result is that no gradients are presented in the spectral indices. So, we have fitted the mean values of each spectral index and central colours to the models of Vazdekis et al. (1996) and Worthey (1994), finding that an intermediate age (~4 Gyr) and metallicity similar to solar (Z=0.02) are the best fitted values for the innermost region of M32.Comment: accepted in MNRA

Optimization of optical data transmitters for 40-Gb/s lightwave systems using frequency resolved optical gating

The measurement technique of frequency resolved optical gating has been used to optimize the phase of a 40-GHz train of optical pulses generated using a continuous-wave laser gated with an external modulator. This technique will be vital for optimization of optical transmitters to be used in systems operating at 40 Gb/s and beyond, as standard measurement techniques will not suffice to optimize such high-speed systems

La vivencia de la sexualidad en las parejas infértiles/estériles

Antecedentes: La infertilidad supone una crisis vital para la pareja. Son abundantes los estudios sobre su impacto psicológico en la mujer y el varón. Se han descrito también disfunciones sexuales debidas a la infertilidad. Objetivo: Realizar una revisión bibliográfica sobre la vivencia de la sexualidad en las parejas infértiles/estériles y revisar si los protocolos de atención a parejas infértiles incluyen el abordaje de la sexualidad. Métodos: Búsqueda en PubMed de estudios descriptivos, analíticos, revisiones y meta- análisis que evalúen la presencia de disfunciones en personas infértiles. Búsqueda de guías de sociedades científicas sobre el abordaje de la infertilidad. Resultados: En las parejas infértiles se han descrito fundamentalmente disminución del deseo sexual, problemas de excitación y orgasmo en la mujer y disfunción eréctil y trastornos eyaculatorios en el varón. Los estudios revisados tienen importantes limitaciones metodológicas que impiden realizar generalizaciones a la población infértil y determinar si la infertilidad aumenta el riesgo de disfunciones sexuales. Existen guías de atención a las parejas infértiles/estériles que incluyen recomendaciones sobre la evaluación y el abordaje de la vivencia de la sexualidad, aunque la mayoría se dirigen a las parejas que recurren a las terapias de reproducción asistida. Conclusiones: Las parejas infértiles pueden presentar disfunciones sexuales. Son aconsejables más estudios, adecuadamente diseñados, para estimar la prevalencia real de disfunciones sexuales en las parejas fértiles e infértiles y dilucidar si la infertilidad es un factor de riesgo para desarrollar dichas disfunciones. De esta manera se mejoraría la información que se ofrece a las parejas infértiles/estériles

Factores de riesgo relacionados con la salud sexual en los jóvenes europeos

En Europa, seguimos asistiendo a un aumento de la transmisión sexual del virus de la inmunodeficiencia humana (VIH) y otras infecciones de transmisión sexual (ITS). Para priorizar estrategias de salud sexual, resulta importante identificar los factores sexuales de riesgo presentes en los jóvenes europeos. Se realizó una revisión sistemática de artículos científicos y estudios de instituciones oficiales europeas. En total, fueron identificados 21 artículos y 10 estudios. Los datos sugieren un aumento de la iniciación sexual juvenil y del número de parejas sexuales. El 15-20% de los jóvenes usan de forma inconstante el preservativo. Entre los conocimientos y actitudes de riesgo detectadas encontramos: desconocer otras ITS distintas al VIH, tener una actitud favorable a las relaciones sexuales casuales, creer erróneamente que algunas medidas son eficaces para prevenir el VIH, desconocer los riesgos de tener múltiples parejas sexuales y desconocer la transmisión sexual del VIH. Los datos subrayan la necesidad de mejorar los mensajes transmitidos a los jóvenes

Analysis of contents about sexuality and human reproduction in school textbooks in Spain

Objectives: The spread of sexually transmitted infections (STI) in adolescents and teenage pregnancy rates are increasing. A decrease in the average age of youth’s first sexual experience is also being noted. Sexual education programs in schools have an important role to play in addressing these issues. The objective of this study is to analyze the content of textbooks in the area of sexuality and human reproduction in order to evaluate the extent to which these textbooks promote healthy reproductive life styles, as well as risk behavior avoidance among the adolescent students. Study design: Descriptive study of school textbooks content. Methods: The study sample consisted of 12 textbooks (about 80% of all the textbooks) used in Spanish secondary school and edited in 2002. A content analysis evaluated the extent to which these books demonstrated reliable scientific information about: a) condom effectiveness; b) consequences, prevention, and treatment of STI; c) family planning methods; d) Assisted reproductive technologies and e) the promotion of healthy reproductive lifestyles. Results: All textbooks presented inaccurate information in the areas studied. Two hundred and eighty one quotes were identified that facilitated an incomplete perception of sexuality or enabled risky behavior. An average of 12.6 incorrect messages was identified in each textbook. Conclusions: The textbooks examined are neither appropriate nor comprehensive enough for adolescent education on issues of sexuality. Results suggest a need for alternative textbooks based on better scientific evidence. It is essential that textbooks empower adolescents to make healthy decisions through the promotion of useful life skills that provide a more integrated concept of sexuality. In any case, there is a need for approaches to sexual education to integrate values commonly held by parents of the youth that use such texts

Properties of dust and detection of Halpha emission in LDN 1780

We present ISOPHOT observations between 60 and 200 microns and a near-infrared extinction map of LDN 1780. We have used the ISOPHOT data together with the 25, 60 and 100 microns IRIS maps to disentangle the warm and cold components of large dust grains that are observed in translucent and dense clouds. The warm and cold components in LDN 1780 have different properties and spatial distributions, with the warm component surrounding the cold component. The cold component is associated with molecular gas at densities of ~1000 cm^-3. The warm component has a uniform colour temperature of 25 K, and the colour temperature of the cold component slightly varies between 15.8 and 17.3 K (beta=2, Delta(T)=0.5 K). The ratio between the 200 microns emission of the cold component and Av is Ic(200)/Av=12.1 MJy/sr/mag and the average ratio tau(200)/Av=2.0x10^-4 mag^-1. The far-infrared emissivity of the warm component is significantly lower than that of the cold component. The Halpha emission and Av correlate very well; a ratio I(Halpha)/Av=2.2 Rayleigh/mag is observed. This correlation indicates the presence of a source of ionisation that can penetrate deeply into the cloud. Using the ratio I(Halpha)/Av we have estimated a ionisation rate for LDN 1780 that results to be ~10^-16 photons/s. We interpret this relatively high value as due to an enhanced cosmic ray flux of ~10 times the standard value. The origin of the cosmic rays could be from supernovae in the Scorpio-Centaurus OB association and/or the runaway zeta Ophiuchus.Comment: 19 pages, 12 figures, accepted for publications in MNRA