The Possible Interstellar Anion CH2CN-: Spectroscopic Constants, Vibrational Frequencies, and Other Considerations

It is hypothesized that the A ^1B_1 <- X ^1A' excitation into the dipole-bound state of the cyanomethyl anion (CH2CN-) is proposed as the carrier for one diffuse interstellar band. However, this particular molecular system has not been detected in the interstellar medium even though the related cyanomethyl radical and the isoelectronic ketenimine molecule have been found. In this study we are employing the use of proven quartic force fields and second-order vibrational perturbation theory to compute accurate spectroscopic constants and fundamental vibrational frequencies for ^1A' CH2CN- in order to assist in laboratory studies and astronomical observations

Which risk factors and signs and symptoms are associated with coccidioidomycosis?

Q: Which risk factors and signs and symptoms are associated with coccidioidomycosis? Evidence-Based Answer: Risk factors for coccidioidomycosis, or valley fever, include lower respiratory tract symptoms lasting longer than 14 days, chest pain, rash, having lived in endemic areas fewer than 10 years, and diabetes mellitus or immunosuppressive conditions (strength of recommendation [SOR]: B, several prospective cohort and case-control studies). The most common signs and symptoms include cough (74%), fever (56%), night sweats (35%), pleuritic chest pain (33%), chills (28%), dyspnea (27%), weight loss (21%), and rash (14%) (SOR: B, retrospective cohort study)

Vibrational Frequencies and Spectroscopic Constants for 1(sup 3)A' HNC and 1(sup 3)A' HOC+ from High-Accuracy Quartic Force Fields

The spectroscopic constants and vibrational frequencies for the 1(sup 3)A' states of HNC, DNC, HOC+, and DOC+ are computed and discussed in this work. The reliable CcCR quartic force field based on high-level coupled cluster ab initio quantum chemical computations is exclusively utilized to provide the anharmonic potential. Then, second order vibrational perturbation theory and vibrational configuration interaction methods are employed to treat the nuclear Schroedinger equation. Second-order perturbation theory is also employed to provide spectroscopic data for all molecules examined. The relationship between these molecules and the corresponding 1(sup 3)A' HCN and HCO+ isomers is further developed here. These data are applicable to laboratory studies involving formation of HNC and HOC+ as well as astronomical observations of chemically active astrophysical environments

Terahertz Radiation Heterodyne Detector Using Two-Dimensional Electron Gas in a GaN Heterostructure

High-resolution submillimeter/terahertz spectroscopy is important for studying atmospheric and interstellar molecular gaseous species. It typically uses heterodyne receivers where an unknown (weak) signal is mixed with a strong signal from the local oscillator (LO) operating at a slightly different frequency. The non-linear mixer devices for this frequency range are unique and are not off-the-shelf commercial products. Three types of THz mixers are commonly used: Schottky diode, superconducting hot-electron bolometer (HEB), and superconductor-insulation-superconductor (SIS) junction. A HEB mixer based on the two-dimensional electron gas (2DEG) formed at the interface of two slightly dissimilar semiconductors was developed. This mixer can operate at temperatures between 100 and 300 K, and thus can be used with just passive radiative cooling available even on small spacecraft

Shortened Telomere Length in White Matter Oligodendrocytes in Major Depression: Potential Role of Oxidative Stress

Telomere shortening is observed in peripheral mononuclear cells from patients with major depressive disorder (MDD). Whether this finding and its biological causes impact the health of the brain in MDD is unknown. Brain cells have differing vulnerabilities to biological mechanisms known to play a role in accelerating telomere shortening. Here, two glia cell populations (oligodendrocytes and astrocytes) known to have different vulnerabilities to a key mediator of telomere shortening, oxidative stress, were studied. The two cell populations were separately collected by laser capture micro-dissection of two white matter regions shown previously to demonstrate pathology in MDD patients. Cells were collected from brain donors with MDD at the time of death and age-matched psychiatrically normal control donors (N=12 donor pairs). Relative telomere lengths in white matter oligodendrocytes, but not astrocytes, from both brain regions were significantly shorter for MDD donors as compared to matched control donors. Gene expression levels of telomerase reverse transcriptase were significantly lower in white matter oligodendrocytes from MDD as compared to control donors. Likewise, the gene expression of oxidative defence enzymes superoxide dismutases (SOD1 and SOD2), catalase (CAT) and glutathione peroxidase (GPX1) were significantly lower in oligodendrocytes from MDD as compared to control donors. No such gene expression changes were observed in astrocytes from MDD donors. These findings suggest that attenuated oxidative stress defence and deficient telomerase contribute to telomere shortening in oligodendrocytes in MDD, and suggest an aetiological link between telomere shortening and white matter abnormalities previously described in MDD

TESS observations of the Pleiades cluster: a nursery for delta Scuti stars

We studied 89 A- and F-type members of the Pleiades open cluster, including five escaped members. We measured projected rotational velocities (v sin i) for 49 stars and confirmed that stellar rotation causes a broadening of the main sequence in the color-magnitude diagram. Using time-series photometry from NASA's TESS Mission (plus one star observed by Kepler/K2), we detected delta Scuti pulsations in 36 stars. The fraction of Pleiades stars in the middle of the instability strip that pulsate is unusually high (over 80%), and their range of effective temperatures agrees well with theoretical models. On the other hand, the characteristics of the pulsation spectra are varied and do not correlate with stellar temperature, calling into question the existence of a useful nu_max relation for delta Scutis, at least for young stars. By including delta Scuti stars observed in the Kepler field, we show that the instability strip is shifted to the red with increasing distance by interstellar reddening. Overall, this work demonstrates the power of combining observations with Gaia and TESS for studying pulsating stars in open clusters.Comment: submitted to AAS journal

Radio-Continuum study of the Nearby Sculptor Group Galaxies. Part 1: NGC 300 at lambda = 20 cm

A series of new radio-continuum (lambda=20 cm) mosaic images focused on the NGC 300 galactic system were produced using archived observational data from the VLA and/or ATCA. These new images are both very sensitive (rms=60 microJy) and feature high angular resolution (<10"). The most prominent new feature is the galaxy's extended radio-continuum emission, which does not match its optical appearance. Using these newly created images a number of previously unidentified discrete sources have been discovered. Furthermore, we demonstrate that a joint deconvolution approach to imaging this complete data-set is inferior when compared to an immerge approach.Comment: 13 pages, 12 figures, accepted to APSS, new version to correct the missing reference

Energy Flow through the Marine Ecosystem of the Lancaster Sound Region, Arctic Canada

This paper synthesizes the trophic dynamics of a Canadian arctic marine ecosystem in so far as it is known, using new data on primary production, zooplankton, the bivalve Mya truncata, and arctic cod (Boreogadus saida), as well as literature values for marine mammals and seabirds. The 98,000 sq km region has a high rate of primary production relative to other parts of arctic Canada. About 60 g C/sq. m are fixed annually, of which approximately 90% is contributed by phytoplankton, 10% by ice algae, and 1% by kelp. Phytoplankton production is twofold higher along the south coast of Cornwallis Island than elsewhere in Barrow Strait. Four copepod species, of which Pseudocalanus acuspes is the most important energetically, graze about one-third of the phytoplankton production. Bivalves maintain high biomass but low energy flow, acting as sedimenting agents. Arctic cod is a major component, with 125,000 tonnes being consumed by marine mammals and 23,000 tonnes by seabirds annually. Our hydro-acoustic estimate for mean arctic cod density, 0.0022 fish/sq. m, is probably too low, partly because we have been unable to quantify dense aggregations of schooling fish. The ecological efficiency of ringed seal is near maximum, with 5% of ringed seal ingestion going to bears and man as seal flesh. The data on total kill and prey consumption in whales and birds is incomplete because they migrate out of the Lancaster Sound region in winter. The food chain is very long, with bears occupying the fifth trophic level; this is reflected by high biomagnification factors for persistent lipophilic pollutants such as PCBs. There are major data gaps for some zooplankton and most of the benthos, as well as for winter populations and energetics. This trophic analysis is therefore incomplete and efficiencies for entire trophic levels cannot be calculated.Key words: seals, whales, seabirds, benthos, zooplankton, phytoplankton, primary production, secondary production, harvest, yieldR&Eacute;SUM&Eacute;. Cet article r&eacute;sume la dynamique trophique de l&rsquo;&eacute;cosyst&egrave;me marin dans le Canada arctique dans la mesure o&ugrave; il est connu, en utilisant de nouvelles donn&eacute;es sur la production primaire, le zooplancton, le bivalve Mya truncata, et la morue polaire (Boreogadus saida), ainsi que les valeurs trouv&eacute;es dans la documentation sur les mammif&egrave;res et les oiseaux marins. Cette r&eacute;gion d&rsquo;une superficie de 98 000 km2 poss&egrave;de un taux &eacute;lev&eacute; de production primaire par rapport &agrave; d&rsquo;autres parties du Canada arctique. Environ 60 g C.m-2 sont fix&eacute;s annuellement, dont environ 90 p. cent par le phytoplancton, 10 p. cent par les algues glaciaires et 1 p. cent par les laminaires. La production de phytoplancton est deux fois plus &eacute;lev&eacute;e le long de la c&ocirc;te m&eacute;ridionale de l&rsquo;&icirc;le Cornwallis qu&rsquo;ailleurs dans le d&eacute;troit de Barrow. Quatre esp&egrave;ces de cop&eacute;podes, dont la Pseudocalanus acuspes est la plus importante du point de vue &eacute;nergitique, utilisent environ un tiers de la production de phytoplancton pour se nourir. Les bivalves contribuent de fa&ccedil;onimportante &agrave; la biomasse mais peu au flux &eacute;nerg&eacute;tique, &eacute;tant des agents de s&eacute;dimentation. La morue arctique est une composante importante, &eacute;tant consomm&eacute;e au taux annuel de 1250 00 tonnes par les mammif&egrave;res marins et de 23 000 tonnes par les oiseaux marins. Notre estimation hydroacoustique pour la densit&eacute; moyenne de la morue arctique, 0,002 poissons.m-2, est probablement trop faible, en partie parce que nous avons &eacute;t&eacute; incapables de quantifier les regroupements denses des poissons se rassemblant en bancs. L&rsquo;efficacit&eacute; &eacute;cologique du phoque annel&eacute; est proche de son maximum, 5 p. cent de l&rsquo;ingestion de cet animal allant &agrave; l&rsquo;ours et &agrave; l&rsquo;homme sous forme de chair de phoque. Les donn&eacute;es sur le nombre d&rsquo;animaux tu&eacute;s et sur laconsommation de proies chez les baleines et les oiseaux sont incompl&egrave;tes en raison de leur migration hivernal &agrave;&nbsp; l'ext&eacute;rieur du d&eacute;troit de Lancaster. La chaine alimentaire est tr&egrave;s longue, les ours occupant le cinqui&egrave;me niveau trophique; cela se traduit par des facteurs de bioamplification &eacute;lev&eacute;s en ce qui concerne les polluants lipophiles persistants tels que les BPC. Il existe des lacunes dans les donn&eacute;es pour certains &eacute;l&eacute;ments du zooplancton et pour la plupart du benthos, ainsi que pour les populations et l&rsquo;&eacute;nerg&eacute;tique hivernales. Cette analyse trophique est donc incompl&egrave;te et il n'est pas possible de calculer l&rsquo;efficacit&eacute; pour l&rsquo;ensemble des niveaux trophiques.Mots cl&eacute;s: phoques, baleines, oiseaux marins, benthos, zooplancton, phytoplancton, production primaire, production secondaire, pr&eacute;l&egrave;vement, rendemen

Periodicities in the high-mass X-ray binary system RXJ0146.9+6121/LSI+61 235

The high-mass X-ray binary RX J0146.9+6121, with optical counterpart LS I+61°235 (V831 Cas), is an intriguing system on the outskirts of the open cluster NGC 663. It contains the slowest Be type X-ray pulsar known with a pulse period of around 1400 s and, primarily from the study of variation in the emission line profile of Hα, it is known to have a Be decretion disc with a one-armed density wave period of approximately 1240 d. Here we present the results of an extensive photometric campaign, supplemented with optical spectroscopy, aimed at measuring short time-scale periodicities. We find three significant periodicities in the photometric data at, in order of statistical significance, 0.34, 0.67 and 0.10 d. We give arguments to support the interpretation that the 0.34 and 0.10 d periods could be due to stellar oscillations of the B-type primary star and that the 0.67 d period is the spin period of the Be star with a spin axis inclination of 23+10−8 degrees. We measured a systemic velocity of −37.0 ± 4.3 km s−1 confirming that LS I+61°235 has a high probability of membership in the young cluster NGC 663 from which the system's age can be estimated as 20–25 Myr. From archival RXTE All Sky Monitor (ASM) data we further find ‘super’ X-ray outbursts roughly every 450 d. If these super outbursts are caused by the alignment of the compact star with the one-armed decretion disc enhancement, then the orbital period is approximately 330 d