Why most molecular clouds are gravitationally dominated

Funding: RJS gratefully acknowledges an STFC Ernest Rutherford fellowship (grant ST/N00485X/1).Observational and theoretical evidence suggests that a substantial population of molecular clouds (MCs) appear to be unbound, dominated by turbulent motions. However, these estimations are made typically via the classical virial parameter α virclass⁠, which is an observational proxy to the virial ratio between the kinetic and the gravitational energy. This parameter intrinsically assumes that MCs are isolated, spherical, and with constant density. However, MCs are embedded in their parent galaxy and thus are subject to compressive and disruptive tidal forces from their galaxy, exhibit irregular shapes, and show substantial substructure. We, therefore, compare the typical estimations of α virclass to a more precise definition of the virial parameter, α virfull⁠, which accounts not only for the self-gravity (as α virclass⁠), but also for the tidal stresses, and thus, it can take negative (self-gravity) and positive (tides) values. While we recover the classical result that most of the clouds appear to be unbound, having α virclass > 2⁠, we show that, with the more detailed definition considering the full gravitational energy, (i) 50 per cent of the total population is gravitationally bound, however, (ii) another 20 per cent is gravitationally dominated, but with tides tearing them apart; (iii) the source of those tides does not come from the galactic structure (bulge, halo, spiral arms), but from the molecular cloud complexes in which clouds reside, and probably (iv) from massive young stellar complexes, if they were present. (v) Finally, our results also suggest that, interstellar turbulence can have, at least partially, a gravitational origin.Peer reviewe

Why most molecular clouds are gravitationally dominated

Observational and theoretical evidence suggests that a substantial population of molecular clouds (MCs) appear to be unbound, dominated by turbulent motions. However, these estimations are made typically via the so-called viral parameter $\alpha_{\rm vir}^{\rm class}$, which is an observational proxy to the virial ratio between the kinetic and the gravitational energy. This parameter intrinsically assumes that MCs are isolated, spherical, and with constant density. However, MCs are embedded in their parent galaxy and thus are subject to compressive and disruptive tidal forces from their galaxy, exhibit irregular shapes, and show substantial substructure. We, therefore, compare the typical estimations of $\alpha_{\rm vir}^{\rm class}$ to a more precise definition of the virial parameter, $\alpha_{\rm vir}^{\rm full}$, which accounts not only for the self-gravity (as $\alpha_{\rm vir}^{\rm class}$), but also for the tidal stresses, and thus, it can take negative (self-gravity) and positive (tides) values. While we recover the classical result that most of the clouds appear to be unbound, having $\alpha_{\rm vir}^{\rm class} > 2$, we show that, with the more detailed definition considering the full gravitational energy, (i) 50\%\ of the total population is gravitationally bound, however, (ii) another 20\%\ is gravitationally dominated, but with tides tearing them apart; (iii) the source of those tides does not come from the galactic structure (bulge, halo, spiral arms), but from the molecular cloud complexes in which clouds reside, and probably (iv) from massive young stellar complexes, if they were present. (v) Finally, our results also suggest that, interstellar turbulence can have, at least partially, a gravitational origin.Comment: 17 pages, 11 figures, submitted to MNRA

Genetic analysis of the vitamin D receptor gene in two epithelial cancers: melanoma and breast cancer case-control studies

<p>Abstract</p> <p>Background</p> <p>Vitamin D serum levels have been found to be related to sun exposure and diet, together with cell differentiation, growth control and consequently, cancer risk. Vitamin D receptor (<it>VDR</it>) genotypes may influence cancer risk; however, no epidemiological studies in sporadic breast cancer (BC) or malignant melanoma (MM) have been performed in a southern European population. In this study, the <it>VDR </it>gene has been evaluated in two epithelial cancers BC and MM.</p> <p>Methods</p> <p>We have conducted an analysis in 549 consecutive and non-related sporadic BC cases and 556 controls, all from the Spanish population, and 283 MM cases and 245 controls. Genotyping analyses were carried out on four putatively functional SNPs within the <it>VDR </it>gene.</p> <p>Results</p> <p>An association with the minor allele A of the non-synonymous SNP rs2228570 (rs10735810, <it>Fok</it>I, Met1Thr) was observed for BC, with an estimated odds ratio (OR) of 1.26 (95% CI = 1.02–1.57; p = 0.036). The synonymous variant rs731236 (<it>Taq</it>I) appeared to be associated with protection from BC (OR = 0.80, 95%CI = 0.64–0.99; p = 0.047). No statistically significant associations with MM were observed for any SNP. Nevertheless, sub-group analyses revealed an association between rs2228570 (<it>FokI</it>) and absence of childhood sunburns (OR = 0.65, p = 0.003), between the 3'utr SNP rs739837 (<it>Bgl</it>I) and fair skin (OR = 1.31, p = 0.048), and between the promoter SNP rs4516035 and the more aggressive tumour location in head-neck and trunk (OR = 1.54, p = 0.020).</p> <p>Conclusion</p> <p>In summary, we observed associations between SNPs in the <it>VDR </it>gene and BC risk, and a comprehensive analysis using clinical and tumour characteristics as outcome variables has revealed potential associations with MM. These associations required confirmation in independent studies.</p

Vertical tubular flocculator: Alternative technology for the improvement of drinking water treatment processes in rural areas

The guarantee of access to safe drinking water for rural communities is a great challenge due to the increase in contamination and deterioration of water sources. Rural areas face technological, financial, and operational limitations, having poor water quality, generally. The purpose of this study was to evaluate the efficiency of a vertical tubular flocculator (VTF) to be used as part of the purification process in rural areas where small flows are used. An experimental treatment system (ETS) implemented in the field was used. The VTF was implemented using PVC pipes and fittings. Tests were carried out with the same raw water used from a conventional treatment plant with aluminum sulfate as a coagulant. The optimal coagulant dose applied in the ETS was determined by the jar test. In the VTF, the length, turbidity, and flow of the raw water were varied. The hydraulic behaviour of the VTF was evaluated with the analysis of the time distribution curve of concentration of a tracer applying the Wolf-Resnick model. A low residence time VTF was obtained, representing a new efficient flocculation model for the reduction of turbidity and colour. The results showed that the turbidity of the raw water, the residence time, and the degree of agitation are important parameters in the operation and efficiency of a VTF. There was a predominance of plug flow in the reactor. The obtained results were compared with the efficiency of a conventional water treatment plant used in the study site. The results obtained indicated that this ETS that integrates a VTF with settling and filtration can be a useful tool for rural areas. It was recommended to replicate this study with wastewater, other dimensions of the VTF, to establish a specific methodology for the design of the VTF, to evaluate the dosage with dose bombs for improving the results of VTF, and to elaborate a hydraulic model for VT

Changes in carotenoid concentration in human postprandial chylomicrons and antioxidant effect in HepG2 caused by differently processed fruit and vegetable soups.

Ten subjects consumed one serving of an optimised or a reference soup produced using modified or traditional processing methods, respectively. Both soups contained the same proportions of carrot, tomato and broccoli, but with 5% olive oil in the optimised soup and 2.5% in the reference soup. The β-carotene content in 600 mL of the optimised/reference soups was 4.10/2.90 mg, and the lycopene content was 3.90/2.71 mg. The β-carotene and lycopene concentrations in chylomicrons isolated from blood serum samples were similar for both groups. Only 50% of subjects could be considered as carotenoid responders and, in agreement with in vitro accessibility data, the β-carotene concentration in the chylomicrons of these subjects was significantly higher in the group consuming the optimised soup, while no changes were found for lycopene. Postprandial chylomicrons from the optimised soup group exhibited significantly higher antioxidant activity in HepG2 cells than the other group. The stimulation of HepG2 cells by human postprandial chylomicrons seems useful for evaluating the antioxidant effect of different food matrices. \ua9 2011 Elsevier Ltd. All rights reserved

Changes in carotenoid concentration in human postprandial chylomicrons and antioxidant effect in HepG2 caused by differently processed fruit and vegetable soups.

Ten subjects consumed one serving of an optimised or a reference soup produced using modified or traditional processing methods, respectively. Both soups contained the same proportions of carrot, tomato and broccoli, but with 5% olive oil in the optimised soup and 2.5% in the reference soup. The β-carotene content in 600 mL of the optimised/reference soups was 4.10/2.90 mg, and the lycopene content was 3.90/2.71 mg. The β-carotene and lycopene concentrations in chylomicrons isolated from blood serum samples were similar for both groups. Only 50% of subjects could be considered as carotenoid responders and, in agreement with in vitro accessibility data, the β-carotene concentration in the chylomicrons of these subjects was significantly higher in the group consuming the optimised soup, while no changes were found for lycopene. Postprandial chylomicrons from the optimised soup group exhibited significantly higher antioxidant activity in HepG2 cells than the other group. The stimulation of HepG2 cells by human postprandial chylomicrons seems useful for evaluating the antioxidant effect of different food matrices. \ua9 2011 Elsevier Ltd. All rights reserved

Benefit of primary percutaneous coronary interventions in the elderly with ST segment elevation myocardial infarction

Objective: Primary percutaneous coronary intervention (P-PCI) has demonstrated its efficacy in patients with ST segment elevation myocardial infarction (STEMI). However, patients with STEMI ≥75 years receive less P-PCI than younger patients despite their higher in-hospital morbimortality. The objective of this analysis was to determine the effectiveness of P-PCI in patients with STEMI ≥75 years. Methods: We included 979 patients with STEMI ≥75 years, from the ATención HOspitalaria del Síndrome coronario study, a registry of 8142 consecutive patients with acute coronary syndrome admitted at 31 Spanish hospitals in 2014-2016. We calculated a propensity score (PS) for the indication of P-PCI. Patients that received or not P-PCI were matched by PS. Using logistic regression, we compared the effectiveness of performing P-PCI versus non-performance for the composite primary event, which included death, reinfarction, acute pulmonary oedema or cardiogenic shock during hospitalisation. Results: Of the included patients, 81.5 % received P-PCI. The matching provided two groups of 169 patients with and without P-PCI. Compared with its non-performance, P-PCI presented a composite event OR adjusted by PS of 0.55 (95% CI 0.34 to 0.89). Conclusions: Receiving a P-PCI was significantly associated with a reduced risk of major intrahospital complications in patients with STEMI aged 75 years or older