2,918 research outputs found
The Molecular Environment of the Gamma-ray Source TeV J2032+4130
The mysterious very high energy gamma-ray source, TeV J2032+4130, is
coincident with the powerful Cygnus OB2 stellar association, though a physical
association between the two remains uncertain. It is possible that the detected
very high energy photons are produced via an overdensity of locally accelerated
cosmic rays impinging on molecular clouds in the source region. In order to
test this hypothesis, we used the Kitt Peak 12m, the Heinrich-Hertz
Submillimeter Telescope (HH-SMT), and the Five College Radio Astronomy
Observatory (FCRAO), to obtain observations in the J=1-->0 and J=2-->1 lines of
both 12CO and 13CO. We report here on the detection of significant molecular
material toward the TeV source region which could be acting as the target of
locally accelerated CRs. We also find evidence of compact molecular clumps,
showing large line widths in the CO spectra, possibly indicative of energetic
processes in this region of Cygnus OB2.Comment: Accepted for publication in ApJ
Political brand identity: an examination of the complexities of Conservative brand and internal market engagement during the 2010 UK General Election campaign
This paper seeks to build an understanding of the importance of internal communications when building a strong political brand. Using Kapferer’s brand prism as a conceptual framework, the paper explores UK Conservative Party members’ attitudes towards the development of the Conservative brand as personified by David Cameron. There are clear implications for political strategists as the findings suggest that it is crucial to engage the internal market in the co-creation of the marketing communications strategy for as brand evangelists they interpret the brand promise at the local level
Hubble Space Telescope Spectroscopy of Brown Dwarfs Discovered with the Wide-field Infrared Survey Explorer
We present a sample of brown dwarfs identified with the {\it Wide-field
Infrared Survey Explorer} (WISE) for which we have obtained {\it Hubble Space
Telescope} ({\it HST}) Wide Field Camera 3 (WFC3) near-infrared grism
spectroscopy. The sample (twenty-two in total) was observed with the G141 grism
covering 1.101.70 m, while fifteen were also observed with the G102
grism, which covers 0.901.10 m. The additional wavelength coverage
provided by the G102 grism allows us to 1) search for spectroscopic features
predicted to emerge at low effective temperatures (e.g.\ ammonia bands) and 2)
construct a smooth spectral sequence across the T/Y boundary. We find no
evidence of absorption due to ammonia in the G102 spectra. Six of these brown
dwarfs are new discoveries, three of which are found to have spectral types of
T8 or T9. The remaining three, WISE J082507.35280548.5 (Y0.5), WISE
J120604.38840110.6 (Y0), and WISE J235402.77024015.0 (Y1) are the
nineteenth, twentieth, and twenty-first spectroscopically confirmed Y dwarfs to
date. We also present {\it HST} grism spectroscopy and reevaluate the spectral
types of five brown dwarfs for which spectral types have been determined
previously using other instruments.Comment: Accepted for publication in the Astrophysical Journal. 20 pages, 18
figures, 7 table
Wolf 1130: A Nearby Triple System Containing a Cool, Ultramassive White Dwarf
Following the discovery of the T8 subdwarf WISEJ200520.38+542433.9 (Wolf
1130C), with common proper motion to a binary (Wolf 1130AB) consisting of an M
subdwarf and a white dwarf, we set out to learn more about the old binary in
the system. We find that the A and B components of Wolf 1130 are tidally
locked, which is revealed by the coherence of more than a year of V band
photometry phase folded to the derived orbital period of 0.4967 days. Forty new
high-resolution, near-infrared spectra obtained with the Immersion Grating
Infrared Spectrometer (IGRINS) provide radial velocities and a projected
rotational velocity (v sin i) of 14.7 +/- 0.7 km/s for the M subdwarf. In
tandem with a Gaia parallax-derived radius and verified tidal-locking, we
calculate an inclination of i=29 +/- 2 degrees. From the single-lined orbital
solution and the inclination we derive an absolute mass for the unseen primary
(1.24+0.19-0.15 Msun). Its non-detection between 0.2 and 2.5 microns implies
that it is an old (>3.7 Gyr) and cool (Teff<7000K) ONe white dwarf. This is the
first ultramassive white dwarf within 25pc. The evolution of Wolf 1130AB into a
cataclysmic variable is inevitable, making it a potential Type Ia supernova
progenitor. The formation of a triple system with a primary mass >100 times the
tertiary mass and the survival of the system through the common-envelope phase,
where ~80% of the system mass was lost, is remarkable. Our analysis of Wolf
1130 allows us to infer its formation and evolutionary history, which has
unique implications for understanding low-mass star and brown dwarf formation
around intermediate mass stars.Comment: 37 pages, 9 Figures, 5 Table
Two New Gravitationally Lensed Double Quasars from the Sloan Digital Sky Survey
We report the discoveries of the two-image gravitationally lensed quasars,
SDSS J0746+4403 and SDSS J1406+6126, selected from the Sloan Digital Sky Survey
(SDSS). SDSS J0746+4403, which will be included in our lens sample for
statistics and cosmology, has a source redshift of z_s=2.00, an estimated lens
redshift of z_l~0.3, and an image separation of 1.08". SDSS J1406+6126 has a
source redshift of z_s=2.13, a spectroscopically measured lens redshift of
z_l=0.27, and an image separation of 1.98". We find that the two quasar images
of SDSS J1406+6126 have different intervening MgII absorption strengths, which
are suggestive of large variations of absorbers on kpc scales. The positions
and fluxes of both the lensed quasar systems are easily reproduced by simple
mass models with reasonable parameter values. These objects bring to 18 the
number of lensed quasars that have been discovered from the SDSS data.Comment: 25 pages, 6 figures, The Astronomical Journal accepte
Does case misclassification threaten the validity of studies investigating the relationship between neck manipulation and vertebral artery dissection stroke? No
Background: The purported relationship between cervical manipulative therapy (CMT) and stroke related to vertebral artery dissection (VAD) has been debated for several decades. A large number of publications, from case reports to case–control studies, have investigated this relationship. A recent article suggested that case misclassification in the case–control studies on this topic resulted in biased odds ratios in those studies. Discussion: Given its rarity, the best epidemiologic research design for investigating the relationship between CMT and VAD is the case–control study. The addition of a case-crossover aspect further strengthens the scientific rigor of such studies by reducing bias. The most recent studies investigating the relationship between CMT and VAD indicate that the relationship is not causal. In fact, a comparable relationship between vertebral artery-related stroke and visits to a primary care physician has been observed. The statistical association between visits to chiropractors and VAD can best be explained as resulting from a patient with early manifestation of VAD (neck pain with or without headache) seeking the services of a chiropractor for relief of this pain. Sometime after the visit the patient experiences VAD-related stroke that would have occurred regardless of the care received. This explanation has been challenged by a recent article putting forth the argument that case misclassification is likely to have biased the odds ratios of the case–control studies that have investigated the association between CMT and vertebral artery related stroke. The challenge particularly focused on one of the case–control studies, which had concluded that the association between CMT and vertebral artery related stroke was not causal. It was suggested by the authors of the recent article that misclassification led to an underestimation of risk. We argue that the information presented in that article does not support the authors’ claim for a variety of reasons, including the fact that the assumptions upon which their analysis is based lack substantiation and the fact that any possible misclassification would not have changed the conclusion of the study in question. Conclusion: Current evidence does not support the notion that misclassification threatens the validity of recent case–control studies investigating the relationship between CMT and VAD. Hence, the recent re-analysis cannot refute the conclusion from previous studies that CMT is not a cause of VAD.https://doi.org/10.1186/s12998-016-0124-
A diagnostic algorithm for detection of urinary tract infections in hospitalized patients with bacteriuria: The "Triple F" approach supported by Procalcitonin and paired blood and urine cultures
For acute medicine physicians, distinguishing between asymptomatic bacteriuria (ABU) and clinically relevant urinary tract infections (UTI) is challenging, resulting in overtreatment of ABU and under-recognition of urinary-source bacteraemia without genitourinary symptoms (USB). We conducted a retrospective analysis of ED encounters in a university hospital between October 2013 and September 2018 who met the following inclusion criteria: Suspected UTI with simultaneous collection of paired urinary cultures and blood cultures (PUB) and determination of Procalcitonin (PCT). We sought to develop a simple algorithm based on clinical signs and PCT for the management of suspected UTI. Individual patient presentations were retrospectively evaluated by a clinical "triple F" algorithm (F1 ="fever", F2 ="failure", F3 ="focus") supported by PCT and PUB. We identified 183 ED patients meeting the inclusion criteria. We introduced the term UTI with systemic involvement (SUTI) with three degrees of diagnostic certainty: bacteremic UTI (24.0%;44/183), probable SUTI (14.2%;26/183) and possible SUTI (27.9%;51/183). In bacteremic UTI, half of patients (54.5%;24/44) presented without genitourinary symptoms. Discordant bacteraemia was diagnosed in 16 patients (24.6% of all bacteremic patients). An alternative focus was identified in 67 patients, five patients presented withS.aureusbacteremia. 62 patients were diagnosed with possible UTI (n = 20) or ABU (n = 42). Using the proposed "triple F" algorithm, dichotomised PCT of < 0.25 pg/ml had a negative predictive value of 88.7% and 96.2% for bacteraemia und accordant bacteraemia respectively. The application of the algorithm to our cohort could have resulted in 33.3% reduction of BCs. Using the diagnostic categories "possible" or "probable" SUTI as a trigger for initiation of antimicrobial treatment would have reduced or streamlined antimicrobial use in 30.6% and 58.5% of cases, respectively. In conclusion, the "3F" algorithm supported by PCT and PUB is a promising diagnostic and antimicrobial stewardship tool
Discovery of a Gravitationally Lensed Quasar from the Sloan Digital Sky Survey: SDSS J133222.62+034739.9
We report the discovery of the two-image gravitationally lensed quasar SDSS
J133222.62+034739.9 (SDSS J1332+0347) with an image separation of
Delta_theta=1.14". This system consists of a source quasar at z_s=1.445 and a
lens galaxy at z_l=0.191. The agreement of the luminosity, ellipticity and
position angle of the lens galaxy with those expected from lens model confirms
the lensing hypothesis.Comment: 16 pages, 4 figures, the Astronomical Journal accepte
- …