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

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&

Molecular gas and star formation towards the IR dust bubble S24 and its environs

We present a multi-wavelength analysis of the infrared dust bubble S24, and its environs, with the aim of investigating the characteristics of the molecular gas and the interstellar dust linked to them, and analyzing the evolutionary status of the young stellar objects (YSOs) identified there. Using APEX data, we mapped the molecular emission in the CO(2-1), $^{13}$CO(2-1), C$^{18}$O(2-1), and $^{13}$CO(3-2) lines in a region of about 5'x 5' in size around the bubble. The cold dust distribution was analyzed using ATLASGAL and Herschel images. Complementary IR and radio data were also used.The molecular gas linked to the S24 bubble, G341.220-0.213, and G341.217-0.237 has velocities between -48.0 km sec$^{-1}$ and -40.0 km sec$^{-1}$. The gas distribution reveals a shell-like molecular structure of $\sim$0.8 pc in radius bordering the bubble. A cold dust counterpart of the shell is detected in the LABOCA and Herschel images.The presence of extended emission at 24 $\mu$m and radio continuum emission inside the bubble indicates that the bubble is a compact HII region. Part of the molecular gas bordering S24 coincides with the extended infrared dust cloud SDC341.194-0.221. A cold molecular clump is present at the interface between S24 and G341.217-0.237. As regards G341.220-0.213, the presence of an arc-like molecular structure at the northern and eastern sections of this IR source indicates that G341.220-0.213 is interacting with the molecular gas. Several YSO candidates are found to be linked to the IR extended sources, thus confirming their nature as active star-forming regions. The total gas mass in the region and the H$_2$ ambient density amount to 10300 M$_{\odot}$ and 5900 cm$^{-3}$, indicating that G341.220-0.213, G341.217-0.237, and the S24 HII region are evolving in a high density medium. A triggering star formation scenario is also investigated.Comment: 17 pages, 16 figures. Submitted to A&A. Revised according to the referee repor

Effect of voicing and articulation manner on aerosol particle emission during human speech.

Previously, we demonstrated a strong correlation between the amplitude of human speech and the emission rate of micron-scale expiratory aerosol particles, which are believed to play a role in respiratory disease transmission. To further those findings, here we systematically investigate the effect of different 'phones' (the basic sound units of speech) on the emission of particles from the human respiratory tract during speech. We measured the respiratory particle emission rates of 56 healthy human volunteers voicing specific phones, both in isolation and in the context of a standard spoken text. We found that certain phones are associated with significantly higher particle production; for example, the vowel /i/ ("need," "sea") produces more particles than /ɑ/ ("saw," "hot") or /u/ ("blue," "mood"), while disyllabic words including voiced plosive consonants (e.g., /d/, /b/, /g/) yield more particles than words with voiceless fricatives (e.g., /s/, /h/, /f/). These trends for discrete phones and words were corroborated by the time-resolved particle emission rates as volunteers read aloud from a standard text passage that incorporates a broad range of the phones present in spoken English. Our measurements showed that particle emission rates were positively correlated with the vowel content of a phrase; conversely, particle emission decreased during phrases with a high fraction of voiceless fricatives. Our particle emission data is broadly consistent with prior measurements of the egressive airflow rate associated with the vocalization of various phones that differ in voicing and articulation. These results suggest that airborne transmission of respiratory pathogens via speech aerosol particles could be modulated by specific phonetic characteristics of the language spoken by a given human population, along with other, more frequently considered epidemiological variables

870 micron continuum observations of the bubble-shaped nebula Gum 31

We are presenting here a study of the cold dust in the infrared ring nebula Gum 31. We aim at deriving the physical properties of the molecular gas and dust associated with the nebula, and investigating its correlation with the star formation in the region, that was probably triggered by the expansion of the ionization front. We use 870 micron data obtained with LABOCA to map the dust emission. The obtained LABOCA image was compared to archival IR,radio continuum, and optical images. The 870 micron emission follows the 8 micron (Spitzer), 250 micron, and 500 micron (Herschel) emission distributions showing the classical morphology of a spherical shell. We use the 870 micron and 250 micron images to identify 60 dust clumps in the collected layers of molecular gas using the Gaussclumps algorithm. The clumps have effective deconvolved radii between 0.16 pc and 1.35 pc, masses between 70 Mo and 2800 Mo, and volume densities between 1.1x10^3 cm^-3 and 2.04x10^5 cm^-3. The total mass of the clumps is 37600 Mo. The dust temperature of the clumps is in the range from 21 K to 32 K, while inside the HII region reaches ~ 40 K. The clump mass distribution is well-fitted by a power law dN/dlog(M/Mo) proportional to M^(-alpha), with alpha=0.93+/-0.28. The slope differs from those obtained for the stellar IMF in the solar neighborhood, suggesting that the clumps are not direct progenitors of single stars/protostars. The mass-radius relationship for the 41 clumps detected in the 870 microns emission shows that only 37% of them lie in or above the high-mass star formation threshold, most of them having candidate YSOs projected inside. A comparison of the dynamical age of the HII region with the fragmentation time, allowed us to conclude that the collect and collapse mechanism may be important for the star formation at the edge of Gum 31, although other processes may also be acting.Comment: 15 pages, 10 figures. Accepted for publication in A&

VLA radio continuum and IRAS observations of the ring nebulae around WR 101 and WR 113

We report radio continuum observations at 1465 MHz obtained with the Very Large Array (VLA) in the DnC configuration toward the ring nebulae associated with the stars WR 101 and WR 113, with resolutions of ∼38″ and 30″, respectively. IRAS images of the nebulae with resolutions of about 2′ (90 M⊙, 40 cm-3) are also analyzed. A remarkable resemblance among the optical, infrared, and radio images of these ring nebulae is observed. The VLA data indicate that Anon. WR 101 is thermal in nature. An ionized mass of ≈230 ± 40 M⊙ and electron densities in the range ≈40-55 cm-3 were estimated for Anon. WR 101. The derived ionized masses and electron densities in the inner and outer shells of the nebula related to WR 113 are ≈20 ± 10 M⊙, 180-500 cm-3 and ≈90 M⊙ 40 cm-3, respectively. Based on infrared data at 60 and 100 μm, the derived masses and temperatures for the dust component in the ring nebula around WR 101 are 0.3-1 M⊙ and ≈40 K. The associated masses suggest that the ring nebula related to WR 101 and the outer arc associated with WR 113 consist of swept-up interstellar matter, while the relatively low ionized mass associated with the inner shell of the nebula around WR 113 may contain a nonnegligible contribution of expelled ejecta material. The derived electron densities for the nebula around WR 101 and the inner shell around WR 113 are comparable to electron densities for other W-R ring nebulae. Low filling factors are inferred for both nebulae. The nebulae probably originated during the current W-R phase of the stars.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

VLA radio continuum and IRAS observations of the ring nebulae around WR 101 and WR 113

We report radio continuum observations at 1465 MHz obtained with the Very Large Array (VLA) in the DnC configuration toward the ring nebulae associated with the stars WR 101 and WR 113, with resolutions of ∼38″ and 30″, respectively. IRAS images of the nebulae with resolutions of about 2′ (90 M⊙, 40 cm-3) are also analyzed. A remarkable resemblance among the optical, infrared, and radio images of these ring nebulae is observed. The VLA data indicate that Anon. WR 101 is thermal in nature. An ionized mass of ≈230 ± 40 M⊙ and electron densities in the range ≈40-55 cm-3 were estimated for Anon. WR 101. The derived ionized masses and electron densities in the inner and outer shells of the nebula related to WR 113 are ≈20 ± 10 M⊙, 180-500 cm-3 and ≈90 M⊙ 40 cm-3, respectively. Based on infrared data at 60 and 100 μm, the derived masses and temperatures for the dust component in the ring nebula around WR 101 are 0.3-1 M⊙ and ≈40 K. The associated masses suggest that the ring nebula related to WR 101 and the outer arc associated with WR 113 consist of swept-up interstellar matter, while the relatively low ionized mass associated with the inner shell of the nebula around WR 113 may contain a nonnegligible contribution of expelled ejecta material. The derived electron densities for the nebula around WR 101 and the inner shell around WR 113 are comparable to electron densities for other W-R ring nebulae. Low filling factors are inferred for both nebulae. The nebulae probably originated during the current W-R phase of the stars.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

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

An H I interstellar bubble surrounding WR 85 and RCW 118

We analyse the distribution of the interstellar matter in the environs of the Wolf-Rayet star LSS 3982 (= WR 85, WN6+OB?) linked to the optical ring nebula RCW118. Our study is based on neutral hydrogen 21-cm line data belonging to the Southern Galactic Plane Survey (SGPS). The analysis of the H I data allowed the identification of a neutral hydrogen interstellar bubble related to WR85 and the 25-arcmin-diameter ring nebula RCW 118. The H I bubble was detected at a systemic velocity of -21.5 km s-1, corresponding to a kinematical distance of 2.8 ± 1.1 kpc, compatible with the stellar distance. The neutral structure is about 25 arcmin in radius or 21 ± 8 pc, and is expanding at 9 ± 2 km s-1. The associated ionized and neutral masses amount to 3000 M⊙ . The carbon monoxide (CO) emission distribution depicts a region lacking CO coincident in position and velocity with the H I structure. The 9.3-arcmin-diameter inner optical nebula appears to be related to the approaching part of the neutral atomic shell. The H I void and shell are the neutral gas counterparts of the optical bubble and have very probably originated in the action of the strong stellar wind of the central star during the O-type and WR phases on the surrounding interstellar medium. The H I bubble appears to be in the momentum conserving stage.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí