Molecular gas associated with IRAS 10361-5830

We analyze the distribution of the molecular gas and the dust in the molecular clump linked to IRAS 10361-5830, located in the environs of the bubble-shaped HII region Gum 31 in the Carina region, with the aim of determining the main parameters of the associated material and investigating the evolutionary state of the young stellar objects identified there. Using the APEX telescope, we mapped the molecular emission in the J=3-2 transition of three CO isotopologues, 12CO, 13CO and C18O, over a 1.5' x 1.5' region around the IRAS position. We also observed the high density tracers CS and HCO+ toward the source. The cold dust distribution was analyzed using submillimeter continuum data at 870 \mu\ obtained with the APEX telescope. Complementary IR and radio data at different wavelengths were used to complete the study of the ISM. The molecular gas distribution reveals a cavity and a shell-like structure of ~ 0.32 pc in radius centered at the position of the IRAS source, with some young stellar objects (YSOs) projected onto the cavity. The total molecular mass in the shell and the mean H$_2$ volume density are ~ 40 solar masses and ~(1-2) x 10$^3$ cm$^{-3}$, respectively. The cold dust counterpart of the molecular shell has been detected in the far-IR at 870 \mu\ and in Herschel data at 350 \mu. Weak extended emission at 24 \mu\ from warm dust is projected onto the cavity, as well as weak radio continuum emission. A comparison of the distribution of cold and warm dust, and molecular and ionized gas allows us to conclude that a compact HII region has developed in the molecular clump, indicating that this is an area of recent massive star formation. Probable exciting sources capable of creating the compact HII region are investigated. The 2MASS source 10380461-5846233 (MSX G286.3773-00.2563) seems to be responsible for the formation of the HII region.Comment: Accepted in A&A. 11 pages, 10 Postscript figure

Quantum Size Effects in the Magnetic Susceptibility of a Metallic Nanoparticle

We theoretically study quantum size effects in the magnetic response of a spherical metallic nanoparticle (e.g. gold). Using the Jellium model in spherical coordinates, we compute the induced magnetic moment and the magnetic susceptibility for a nanoparticle in the presence of a static external magnetic field. Below a critical magnetic field the magnetic response is diamagnetic, whereas above such field the magnetization is characterized by sharp, step-like increases of several tenths of Bohr magnetons, associated with the Zeeman crossing of energy levels above and below the Fermi sea. We quantify the robustness of these regimes against thermal excitations and finite linewidth of the electronic levels. Finally, we propose two methods for experimental detection of the quantum size effects based on the coupling to superconducting quantum interference devices.Comment: 5+6 pages, 3+3 figure

Influence of the soil water content and distribution on both the hydraulic and transpiration performance of 'Manzanilla' olive trees

8 páginas, 4 figuras, 20 referencias.-- VI International Symposium on Irrigation of Horticultural Crops, celebrado del 2-6 de noviembre de 2006 en Viña del Mar, Chile.-- [email protected] work was made with mature 'Manzanilla' olive trees in an orchard of a semi-arid area in southern Spain. Three water treatments were considered: Rainfed, in which the trees had rainfall as the only source of water supply; FAO, in which the trees were under localized irrigation to replace the crop water demand, with some roots left in drying soil; Pond, in which the whole rootzones of the trees were maintained under non-limiting soil water conditions for the whole dry season. Our aim was to obtain information on the mechanisms behind the reduction of transpiration (Ep) in the FAO trees, as compared to the Pond trees. Our results show a near-isohydric behaviour of the FAO trees, i.e. those trees under localized irrigation in which some roots are left in drying showed lower stomatal conductance than the Pond trees in which all roots were in wetted soil. This helped the FAO trees to maintain similar leaf water potentials than the Pond trees. In addition, the FAO trees maintained a constant difference between the water potential of the canopy and that in the soil. This has been described as an isohydrodynamic behaviour, and it is thought to be an improvement over a typically anisohydric behaviour. These mechanisms were behind the similar values of tree hydraulic conductance (K p) found in the FAO and Pond treatments. The Rainfed trees showed lower Kp values because of the low Ep values of those trees, due to the low soil water availability in that treatment. Our results show, however, that the Rainfed trees were able to maintain similar values of Kp all throughout the dry season, which shows that the hydraulic efficiency of the xylem of those trees was little affected by embolism, despite of the high demanding conditions in the area.This work has been funded by the Spanish Ministry of Education and Science, research project No.AGL2006-04666/AGR, and by the EU, research project ref. STREP 023120.Peer Reviewe

Hipogonadismo prolongado tras la suspensión de tratamiento hormonal en pacientes con cáncer de próstata

Objetivos: Estudiar los niveles de LH, testosterona y PSA tras suspender el tratamiento prolongado con análogos LH-RH Material y Método: Se estudió la evolución hormonal de 29 pacientes a los que se les retiró el tratamiento. Los pacientes previamente habían seguido tratamiento con análogo LH-RH por más de un año y con LH<2 mUI/mL y testosterona <2,8 ng/mL. Se determinó mensualmente la LH, testosterona y PSA junto con valoración clínica. Se reinicia el tratamiento y el tiempo de seguimiento finaliza ante la presencia de progresión clínica y/o PSA ≥ 10 ng/mL. Se realizó descripción de la cohorte, el cálculo de supervivencia mediante Kaplan-Meier y regresión de Cox. Resultados: El tiempo medio sin tratamiento de la serie fue de 35 meses (IC 95% 15,7-54,2 meses). El 17% de los pacientes presentaron hipogonadismo prolongado (>24 meses). La recuperación del eje LH-T-PSA, cuando se produjo, siguió la secuencia esperada. Las variables que influyeron en el tiempo de recuperación del PSA fueron el PSA pretratamiento y la asociación de antiandrógeno. Conclusiones: Tras retirar el tratamiento prolongado con análogos LH-RH la mayoría de los pacientes recuperan los niveles de LH-T-PSA si bien un subgrupo se mantienen hipogonádicos más de 24 meses.Objectives: To study the levels of LH, testosterone and PSA after suspending prolonged treatment with LH-RH analogs. Materials and Method: Hormonal evolution was studied in 29 patients from whom treatment had been withdrawn. The patients had previously been receiving treatment with LH-RH analog for more than one year, and with LH< 2 mUI/mL and testosterone <2.8 ng/mL. LH, testosterone and PSA were determined monthly, together with clinical assessment. The treatment was re-initiated and the period of monitoring ended before the presence of clinical progression and/or PSA ≥ 10 ng/mL. The cohort was described and survival was calculated using Kaplan-Meier and Cox regression. Results: The mean period of time without treatment for the series was 35 months (CI 95%, 15.7-54.2 months). Prolonged hypogonadism (> 24 months) was presented by 17% of the patients. The recovery of the LH-T-PSA axis, when it occurred, followed the expected sequence. The variables that influenced the period of recovery of the PSA were the PSA pretreatment and the association of an antiandrogen. Conclusions: After withdrawing the prolonged treatment with LH-RH analogs, most of the patients recovered the levels of LH-T-PSA, although a subgroup remained hypogonadic for more than 24 months

The role of extracellular matrix on liver stem cell fate: A dynamic relationship in health and disease

The liver stem cell niche is a specialized and dynamic microenvironment with biomechanical and biochemical characteristics that regulate stem cell behavior. This is feasible due to the coordination of a complex network of secreted factors, small molecules, neural, blood inputs and extracellular matrix (ECM) components involved in the regulation of stem cell fate (self-renewal, survival, and differentiation into more mature phenotypes like hepatocytes and cholangiocytes). In this review, we describe and summarize all the major components that play essential roles in the liver stem cell niche, in particular, growth factor signaling and the biomechanical properties of the ECM