The modifcation by diffuse radiation of "cometary tail" formation behind globules

We study the evolution of a globule of neutral material immersed in the more tenuous hotter plasma of an H II region surrounding newly born OB stars. The neutral globule is illuminated by the direct ionizing radiation of OB stars, and by diffuse radiation emitted by recombination in the surrounding ionized gas. We perform 2D, time dependent axisymmetric hydrodynamic simulations, and find that, for values of the diffuse field of the order of 10% of the direct field, the evolution of the globule is completely different to its evolution when the diffuse field is neglected

Modelling the direct effect of aerosols in the solar near-infrared on a planetary scale

International audienceWe used a spectral radiative transfer model to compute the direct radiative effect (DRE) of natural plus anthropogenic aerosols in the solar near-infrared (IR), between 0.85?10 µm, namely, their effect on the outgoing near-IR radiation at the top of atmosphere (TOA, ?FTOA), on the atmospheric absorption of near-IR radiation (?Fatmab) and on the surface downward and absorbed near-IR radiation (?Fsurf, and ?Fsurfnet, respectively). The computations were performed on a global scale (over land and ocean) under all-sky conditions, using spectral aerosol optical properties taken from the Global Aerosol Data Set (GADS) supplemented by realistic data for the rest of surface and atmospheric parameters. The computed aerosol DRE, averaged over the 12-year period 1984?1995 for January and July, shows that aerosols produce a planetary cooling by increasing the scattered near-IR radiation back to space (by up to 6 Wm?2), they warm the atmosphere (by up to 7 Wm?2) and cool the surface (by up to 12 Wm?2). However, they can also slightly warm the Earth-atmosphere system or cool the atmosphere (by less than 1 Wm?2) over limited areas. The magnitude of the near-IR aerosol DRE is smaller than that of the combined ultraviolet (UV) and visible DRE, but it is still energetically important, since it contributes to the total shortwave (SW) DRE by 22?31%. On a global mean basis, the DREs ?FTOA, ?Fatmab, ?Fsurf, and ?Fsurfnet are equal to about 0.48, 0.37, ?1.03 and ?0.85 Wm?2, i.e. their magnitude is similar to that of climate forcing associated with increasing concentrations of greenhouse gases. The aerosol induced near-IR surface cooling combined with the atmospheric warming, affects the thermal dynamics of the Earth-atmosphere system, by increasing the atmospheric stability, decreasing thus cloud formation, and precipitation, especially over desertification threatened regions such as the Mediterranean basin. This, together with the fact that the sign of near-IR aerosol DRE is sometimes opposite to that of UV-visible DRE, demonstrates the importance of performing detailed spectral computations to provide estimates of the climatic role of aerosols for the Earth-atmosphere system

Prognostic factors identifying biochemical recurrence in patients with positive margins after radical prostatectomy

Background There is a discrepancy in reporting biochemical recurrence (BCR) rates in patients with positive surgical margins (PSM) after a radical prostatectomy (RP), ranging between 19 and 61%. Our aim was to identify the parameters that contribute to the absence of BCR in patients with PSM by performing a multivariate analysis. Methods From a cohort of 1163 patients who underwent open RP over a 6-year period, 69 exhibited PSM. Of the 69, 39 had and 30 did not have a BCR during a 3-year follow-up. The analysis comprised preoperative and postoperative PSA serum levels, age, weight of the prostate, pathology tumor grade, time of BCR, number and location of PSM. Results In the univariate analysis, the weight of prostate was statistically significantly associated with the odds of BCR (P = 0.027, 95% CI 1.00-1.06). Bladder neck and lateral locations of PSM were negatively associated with BCR, without exhibiting statistical significance in the multivariate analysis. Age was negatively associated with the odds of BCR whereas preoperative PSA, stage and Gleason score were positively associated, but did not exhibit statistical significance in both uni- and multivariate analysis. Conclusions A low weight prostate, younger age, bladder neck and lateral location of PSM seem to protect patients from having a BCR. On the other hand, preoperative PSA, stage of the disease and Gleason score do contribute to the occurrence of BCR. Lack of statistical significance in the above results could be attributed to the small number of patients due to the study's low PSM rate. © Springer Science+Business Media, B.V. 2010