1,471 research outputs found
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 volume density are ~ 40 solar masses and
~(1-2) x 10 cm, 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
Performance and genome-centric metagenomics of thermophilic single and two-stage anaerobic digesters treating cheese wastes
The present research is the first comprehensive study regarding the thermophilic anaerobic degradation of cheese wastewater, which combines the evaluation of different reactor configurations (i.e. single and two-stage continuous stirred tank reactors) on the process efficiency and the in-depth characterization of the microbial community structure using genome-centric metagenomics. Both reactor configurations showed acidification problems under the tested organic loading rates (OLRs) of 3.6 and 2.4 g COD/L-reactor day and the hydraulic retention time (HRT) of 15 days. However, the two-stage design reached a methane yield equal to 95% of the theoretical value, in contrast with the single stage configuration, which reached a maximum of 33% of the theoretical methane yield. The metagenomic analysis identified 22 new population genomes and revealed that the microbial compositions between the two configurations were remarkably different, demonstrating a higher methanogenic biodiversity in the two-stage configuration. In fact, the acidogenic reactor of the serial configuration was almost solely composed by the lactose degrader Bifidobacterium crudilactis UC0001. The predictive functional analyses of the main population genomes highlighted specific metabolic pathways responsible for the AD process and the mechanisms of main intermediates production. Particularly, the acetate accumulation experienced by the single stage configuration was mainly correlated to the low abundant syntrophic acetate oxidizer Tepidanaerobacter acetatoxydans UC0018 and to the absence of aceticlastic methanogens
Domains of elliptic operators on sets in Wiener space
Let X be a separable Banach space endowed with a non-degenerate centered Gaussian measure ÎŒ. The associated Cameron-Martin space is denoted by H. Consider two sufficiently regular convex functions U: X â R and G: X âR We let Îœ = e-UÎŒ and Ï = G-1(-â, 0]. In this paper, we study the domain of the self-adjoint operator associated with the quadratic form {equation presented} and we give sharp embedding results for it. In particular, we obtain a characterization of the domain of the Ornstein-Uhlenbeck operator in Hilbert space with Ï = X and on half-spaces, namely if U 0 and G is an affine function, then the domain of the operator defined via (0.1) is the space u {equation presented}, where Ï is the Feyel-de La Pradelle Hausdorff-Gauss surface measure
Unveiling the molecular environment of the ring nebula RCW 78
We present a study of the ionized, neutral atomic, and molecular gas
associated with the ring nebula RCW 78 around the WR star HD 117688 (= WR 55).
We based our study on CO observations carried out with the SEST and NANTEN
telescopes. We report the detection of molecular gas with velocities in the
range -56 to -33 km/s. The CO emission is mainly connected to the western
section, with a total molecular mass of 1.3 x 10^5 solar masses. The analysis
of the HI gas distribution reveals the HI envelope of the molecular cloud,
while the radio continuum emission shows a ring-like structure, which is the
radio counterpart of the optical nebula. The gas distribution is compatible
with the western section of RCW 78 having originated in the photodissociation
and ionization of the molecular gas by HD 117688, and with the action of the
stellar winds of the WR star. A number of infrared point sources classified as
YSO candidates showed that stellar formation activity is present in the
molecular gas linked to the nebula. The fact that the expansion of the bubble
have triggered star formation in this region can not be discarded.Comment: 15 pages, 11 Postscript figures, to be published in A&
Influence of Cooking Conditions on Nutritional Properties and Sensory Characteristics Interpreted by E-Senses: Case-Study on Selected Vegetables
This study investigates the effects of three cooking methods (boiling, steaming and microwaving) on the nutritional and physical properties of cauliflowers, carrots and sweet potatoes; e-senses were applied to interpret the sensory characteristics according to physico-chemical aspects. The nutritional quality was evaluated by determining the concentrations of key components and the antioxidant activity; e-sense data, combined with texture parameters, were processed by a principal component analysis. The cooking method and time significantly influenced the quality of the three products. Boiling, which detrimentally affected ascorbic acid, total phenolic concentration and antioxidant activity, enhanced carotene accessibility. Steaming produced losses in ascorbic acid, increasing total phenolics and carotenoids. Microwaving resulted in minor changes in ascorbic acid concentrations, preserved carotenoids and increased total phenolics. The nutritional quality was better preserved or enhanced using shorter cooking times. The elaboration of the data collected by the e-senses showed a clear evolution according to the cooking method and time. The results helped to determine the cooking method that best preserves the nutritional properties of the vegetables, highlighting the applicability of rapid instrumental methods to interpret the evolution of sensory characteristics
HJB Equations and Stochastic Control on Half-Spaces of Hilbert Spaces
In this paper, we study a first extension of the theory of mild solutions for HamiltonâJacobiâBellman (HJB) equations in Hilbert spaces to the case where the domain is not the whole space. More precisely, we consider a half-space as domain, and a semilinear HJB equation. Our main goal is to establish the existence and the uniqueness of solutions to such HJB equations, which are continuously differentiable in the space variable. We also provide an application of our results to an exit-time optimal control problem, and we show that the corresponding value function is the unique solution to a semilinear HJB equation, possessing sufficient regularity to express the optimal control in feedback form. Finally, we give an illustrative example
Sh2-205: II. Its quiescent stellar formation activity
We present a study of active stellar forming regions in the environs of the
HII region Sh2-205. The analysis is based on data obtained from point source
catalogues and images extracted from 2MASS, MSX, and IRAS surveys.
Complementary data are taken from CO survey. The identification of primary
candidates to stellar formation activity is made following colour criteria and
the correlation with molecular gas emission.
A number of stellar formation tracer candidates are projected on two
substructures of the HII region: SH148.83-0.67 and SH149.25-0.00. However, the
lack of molecular gas related to these structures casts doubts on the nature of
the sources. Additional infrared sources may be associated with the HI shell
centered at (l,b) = (149\degr 0\arcmin, -1\degr 30\arcmin).
The most striking active area was found in connection to the HII region LBN
148.11-0.45, where stellar formation candidates are projected onto molecular
gas. The analytical model to the "collect and collapse" process shows that
stellar formation activity could have been triggered by the expansion of this
HII region.Comment: Accepted for publication in MNRAS, 10 pages, 5 figures, 5 table
Effect of testosterone metabolites on ABC half-transporter relative gene expression in X-linked adrenoleukodystrophy
X-linked adrenoleukodystrophy (X-ALD) is an inherited neurodegenerative disorder associated with reduced very long-chain fatty acid beta-oxidation, mainly affecting the nervous system, the adrenal cortex and the testes. The clinical manifestations of hypogonadism, alopecia and the impairment of the enzyme 5alpha-reductase, which converts testosterone into dihydrotestosterone, clearly point to an involvement of androgens in this pathology. The disease is characterized by mutations in the ABCD1 gene, which codes for the peroxisomal ABC half-transporter ALDP, and by a broad range of clinical manifestations. The altered function of ALDP can be compensated by the overexpression of proteins belonging to the same family of ABC half-transporters. A promising therapeutic approach is represented by the activation of these proteins by specific agonists. In this study we evaluated the effect of the testosterone metabolite dihydrotestosterone (DHT) and 5alpha-androstan-3alpha,17beta-diol (3alpha-diol) on the expression of the ABC half-transporters encoded by the ABCD2 and ABCD3 genes, in fibroblasts drawn from controls and from two affected brothers. The two patients presented the same mutation in exon 9 but had different clinical manifestations, one patient being asymptomatic and the second one severely affected. When the cells were stimulated with testosterone metabolites, only the severely affected patient showed a significant increase in ABCD2 mRNA levels, while the ABCD3 expression remained unchanged in both patients
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