Short-timescale Fluctuations in the Difference Light Curves of QSO 0957+561A,B: Microlensing or Noise?

From optical R band data of the double quasar QSO 0957+561A,B, we made two new difference light curves (about 330 days of overlap between the time-shifted light curve for the A image and the magnitude-shifted light curve for the B image). We observed noisy behaviours around the zero line and no short-timescale events (with a duration of months), where the term event refers to a prominent feature that may be due to microlensing or another source of variability. Only one event lasting two weeks and rising - 33 mmag was found. Measured constraints on the possible microlensing variability can be used to obtain information on the granularity of the dark matter in the main lensing galaxy and the size of the source. In addition, one can also test the ability of the observational noise to cause the rms averages and the local features of the difference signals. We focused on this last issue. The combined photometries were related to a process consisting of an intrinsic signal plus a Gaussian observational noise. The intrinsic signal has been assumed to be either a smooth function (polynomial) or a smooth function plus a stationary noise process or a correlated stationary process. Using these three pictures without microlensing, we derived some models totally consistent with the observations. We finally discussed the sensitivity of our telescope (at Teide Observatory) to several classes of microlensing variability.Comment: MNRAS, in press (LaTeX, 14 pages, 22 eps figures

Phonon modulation of the spin-orbit interaction as a spin relaxation mechanism in InSb quantum dots

We calculate the spin relaxation rates in a parabolic InSb quantum dots due to the spin interaction with acoustical phonons. We considered the deformation potential mechanism as the dominant electron-phonon coupling in the Pavlov-Firsov spin-phonon Hamiltonian. By studying suitable choices of magnetic field and lateral dot size, we determine regions where the spin relaxation rates can be practically suppressed. We analyze the behavior of the spin relaxation rates as a function of an external magnetic field and mean quantum dot radius. Effects of the spin admixture due to Dresselhaus contribution to spin-orbit interaction are also discussed.Comment: 5 page, 2 figures, accepted in Phonons 2007 proceeding

Determination of the properties of the central engine in microlensed QSOs

We study a recently observed gravitational microlensing peak in the V-band light curve of Q2237+0305A using a relatively simple, but highly consistent with the data (the best-fit reduced \chi^2 is very close to 1), physical model. The source quasar is assumed to be a Newtonian geometrically-thin and optically-thick accretion disk. The disk has an arbitrary orientation, and both blackbody and greybody emission spectra are considered. When the electron-photon scattering plays a role, the greybody spectrum will be a simplified version of the exact one. In our model the microlensing variability result from the source crossing a caustic straight line. The main goal is to estimate the black hole mass and the mass accretion rate in QSO 2237+0305 as well as to discuss the power and the weakness of the technique, some possible improvements, and the future prospects from multifrequency monitoring of new microlensing peaks. We also put into perspective the new methodology and the results on the central engine in QSO 2237+0305. From the fitted microlensing parameters and reasonable dynamical/cosmological constraints, it is concluded that QSO 2237+0305 harbours a central massive black hole: 10^7 M_Sun < M < 6 10^8 M_Sun. While the information about the central dark mass is very interesting, the mass accretion rate is not so well constrained. The typical values of the disk luminosity/Eddington luminosity ratio are in the (1-20)*\epsilon range, where \epsilon \leq 1 is the emissivity relative to a blackbody and the highest L/L_{Edd} ratio corresponds to the largest deflector motion. Therefore, in order to verify L/L_{Edd} \leq 1, a relatively small projected peculiar motion of the lens galaxy and a greybody emission seem to be favored.Comment: Astron. Astrophys., in press (LaTeX, 18 pages, 4 eps figures

Assessing Psychosocial Work Environments of Coaches in Spain and Their Relationships With Mental Health, Behavioral Stress Symptoms, and Burnout

The purpose of this study was to assess the psychosocial work environments (PWE) among a sample of coaches in comparison to the reference values of the Spanish general workforce, as well as to explore the relationship between PWE and mental health, behavioral stress symptoms, and burnout. A representative sample (n=1481) of Spanish coaches (18.1% women, Mage=32.98, SD=11.60) completed a battery of questionnaires. Results showed that, in comparison to the general workforce, coaches showed statistically significant differences in most of the PWE areas assessed. The emotional demands experienced by coaches are a risk for health, while trust regarding management and recognition are positive features in their PWE. Coaches’ emotional demands were associated with low mental health scores and higher levels of behavioral stress symptoms and burnout, whereas social community at work and role clarity were protective factors for health. Practical implications to provide more favorable work environments for coaches are discussed

S-Abscisic acid, 2-chloroethylphosphonic acid and indole-3-acetic acid treatments modify grape (Vitis vinifera L. 'Cabernet Sauvignon') hormonal balance and wine quality

The phenolic composition of red wine strongly determines its quality. Even when the applications of plant  growth regulator (PGR) affect grape quality, there is  almost no information on the effect of these treatments  on the grape’s internal hormonal balance and the wine  composition and quality. In the present study, changes in the internal hormonal content following the application of (+)-S-abscisic acid (S-ABA), 2-chloroethylphosphonic acid (CEPA) and indole-3-acetic acid (IAA) at veraison were examined to determine their effects on 'Cabernet Sauvignon' grapes and wine composition in a plants in containers experiment and in a commercial vineyard experiment. Applied PGRs had a significant effect on the hormonal balance and phenolic composition of grape skins. The S-ABA-treated grapes showed a significantly higher skin internal free abscisic acid concentration in the plants in container experiment and the CEPA-treated grapes showed a reduction in skin internal IAA concentration in the commercial vineyard experiment. Winemaking was performed in the commercial vineyard experiment. Wine’s chemical composition was affected by these treatments and an up-to 63 % increase in malvidin-3-glucoside concentration and an up-to 70 % increase in total tannin concentration were found in wines made from the CEPA-treated grapes. The alcohol content was 10.3 % higher (from 12.6 to 13.9 % v v-1) in wines made from the CEPA-treated grapes. No significant differences in the wine sensory attributes (aroma and mouth-feel) between the control and the PGR-treated wines were identified by a sensory panel.

Psycho-oncological support for breast cancer patients: A brief overview of breast cancer services certification schemes and national health policies in Europe.

Psycho-oncology addresses the psychological, social, behavioural, and ethical aspects of cancer. Identification and proper management of the patients' psychosocial needs, as well as the needs of their caregivers and family are essential for a person-centred concept of breast cancer care. The aim of this overview is to describe how psychosocial support in breast cancer is incorporated in cancer-related policy documents, such as national cancer plans and breast cancer care certification schemes.post-print163 K