2,144 research outputs found
Verifying the mass-metallicity relation in damped Lyman-alpha selected galaxies at 0.1<z<3.2
A scaling relation has recently been suggested to combine the galaxy
mass-metallicity (MZ) relation with metallicities of damped Lyman-alpha systems
(DLAs) in quasar spectra. Based on this relation the stellar masses of the
absorbing galaxies can be predicted. We test this prediction by measuring the
stellar masses of 12 galaxies in confirmed DLA absorber - galaxy pairs in the
redshift range 0.1<z<3.2. We find an excellent agreement between the predicted
and measured stellar masses over three orders of magnitude, and we determine
the average offset = 0.44+/-0.10 between absorption
and emission metallicities. We further test if could depend on the
impact parameter and find a correlation at the 5.5sigma level. The impact
parameter dependence of the metallicity corresponds to an average metallicity
difference of -0.022+/-0.004 dex/kpc. By including this metallicity vs. impact
parameter correlation in the prescription instead of , the scatter
reduces to 0.39 dex in log M*. We provide a prescription how to calculate the
stellar mass (M*,DLA) of the galaxy when both the DLA metallicity and DLA
galaxy impact parameter is known. We demonstrate that DLA galaxies follow the
MZ relation for luminosity-selected galaxies at z=0.7 and z=2.2 when we include
a correction for the correlation between impact parameter and metallicity.Comment: 15 pages, 6 figures. Major revision. Accepted for publication in
MNRA
Accounting Fraud at Xerox Corporation: Ethical Considerations
Management at Xerox Corporation faced with strategic mistakes and tough economic environment resorted to creative accounting to meet financial targets and Wall Street expectations. This case presents a brief history of Xerox Corporation, followed by Xerox’s corporate culture in the 1980s & 90s, and the SEC investigation. The focus of the case is the actions of an assistant treasurer that top management used to guide Xerox through tough economic times and help make financial results appear more favorable. A teaching note is included. The case may also be used for exploring strategic issues or accounting issues and the mechanics of GAAP violations
Extinction curve template for intrinsically reddened quasars
We analyze the near-infrared to UV data of 16 quasars with redshifts ranging
from 0.71 2.13 to investigate dust extinction properties. The
sample presented in this work is obtained from the High Quasar (HAQ)
survey. The quasar candidates were selected from the Sloan Digital Sky Survey
(SDSS) and the UKIRT Infrared Deep Sky Survey (UKIDSS), and follow-up
spectroscopy was carried out at the Nordic Optical Telescope (NOT) and the New
Technology Telescope (NTT). To study dust extinction curves intrinsic to the
quasars, from the HAQ survey we selected 16 cases where the Small Magellanic
Cloud (SMC) law could not provide a good solution to the spectral energy
distributions (SEDs). We derived the extinction curves using Fitzpatrick &
Massa 1986 (FM) law by comparing the observed SEDs to the combined quasar
template from Vanden Berk et al. 2001 and Glikman et al. 2006. The derived
extinction, , ranges from 0.2-1.0 mag. All the individual extinction
curves of our quasars are steeper (-2.7) than that of the SMC, with a
weighted mean value of . We derive an `average quasar extinction
curve' for our sample by fitting SEDs simultaneously by using the weighted mean
values of the FM law parameters and a varying . The entire sample is well
fit with a single best-fit value of . The `average quasar
extinction curve' deviates from the steepest Milky Way and SMC extinction
curves at a confidence level . Such steep extinction curves
suggest a significant population of silicates to produce small dust grains.
Moreover, another possibility could be that the large dust grains may have been
destroyed by the activity of the nearby active galactic nuclei (AGN), resulting
in steep extinction curves.Comment: 8 pages, 4 figures, 1 tabl
Marketing Dynamics of a Hotel Tax: The Case of Chautauqua County, New York
Imposing a hotel tax in Chautauqua County, New York, which has natural attractions and the proximity of viable markets, might be highly likely to contribute significantly to the economic climate for the county. The authors examine the likely impact of hotel taxes, review hotel tax rates in cities across the country and in New York State, recommend revenue distribution, and propose a process by which hotel tax revenues can be equitably and efficiently disburse
Anaesthesia for surgical correction of scoliosis with spinal cord monitoring--a case series
Objective: To share our experience of anaesthetic management of scoliosis with intra-operative somatosensory evoked potential monitoring and wake up test.Methods: All the cases of scoliosis surgery scheduled during a period of two years in which SSEP and intra-operative wake-up test was planned were included in the study. The patient in which intra-operative wake-up test was not planned were excluded from this case series.Results: We managed a series of sixteen cases of scoliosis in our hospital. Eleven patients were female and five were male with the age ranging from six to twenty two years. SSEPs were monitored throughout the procedure and wake up test was done intra-operatively after surgical manipulation of spinal cord. Intra-operative wake-up test was completed successfully in all the patients. None of the patients had any neurological damage and were also successfully extubated at the end of procedure.CONCLUSION: Intra-operative wake up test and SSEP monitoring are reliable methods for detection of intra-operative spinal cord ischemia during scoliosis surgery
Personalized Gravestones: Your Life\u27s Passion for All to See and Hear
In the past several years, a trend has developed that in an earlier age would have seemed inappropriate and perhaps even morbid; the increased personalization of gravestones (memorials). What makes this trend interesting is the variety of shapes, designs, manufacturing processes, and types of personalization actually appearing on gravestones, including seven-inch LCD (Liquid Crystal Display) screens recessed into the face of memorials. This paper discusses gravestones (memorials) in a religious context. It examines the rapidly developing market for elaborately designed memorials both in their traditional forms, typically vertical and created out of granite with just a name and date of death, to memorials in every conceivable size, shape and colour portraying scenes of the deceased\u27s everyday life. Although this paper concentrates on memorials found in Christian, mostly Catholic and Protestant cemeteries, references to personalization, or lack of it, in Jewish and Muslim cemeteries are also discussed. Briefly addressed are references to advances in the latest engraving processes that are now making these personalized memorials possible
Knowledge of primary paediatric care providers regarding attention deficit hyperactivity disorder and learning disorder: a study from Pakistan
Introduction: Attention deficit hyperactivity disorder (ADHD) and learning disorder (LD) remain prevalent globally and are also speculated to have a high occurrence in Pakistan. An early diagnosis and intervention in these disabilities is imperative for achieving good clinical and functional outcomes. This can be ensured by an effective screening at the level of primary paediatric care in the developing countries. We aimed to explore the ability of general practitioners (GPs) and paediatricians in Pakistan to screen for ADHD and LD based on their awareness regarding the risk factors and symptomatology of ADHD and LD. Methods: A total of 96 paediatricians and 98 GPs practising in Karachi, Pakistan were included in the study. Data was collected employing a self-administered questionnaire. Results: Only 13.7 percent of the GPs and 21.6 percent of the paediatricians were shown to have knowledge sufficient to effectively screen for / diagnose ADHD. Alarmingly, not a single GP was adequately familiar with the established risk factors and clinical symptoms of LD. The level of knowledge was not influenced by age, gender, and clinical practice attributes of the physicians. Doctors who regularly read medical journals and attend medical education seminars showed slightly better trends. Conclusion : We hypothesise that this demonstrated lack of knowledge at the level of primary care in Pakistan prevents an early screening of ADHD and LD. A multipronged strategy targeted at the provision of objective screening tools for primary paediatric care providers, regular continuing medical education seminars and an emphasis on paediatric mental health in undergraduate and postgraduate curricula may ensure an early detection of ADHD and LD in Pakistan
On the mass-metallicity relation, velocity dispersion and gravitational well depth of GRB host galaxies
We analyze a sample of 16 absorption systems intrinsic to long duration GRB
host galaxies at for which the metallicities are known. We
compare the relation between the metallicity and cold gas velocity width for
this sample to that of the QSO-DLAs, and find complete agreement. We then
compare the redshift evolution of the mass-metallicity relation of our sample
to that of QSO-DLAs and find that also GRB hosts favour a late onset of this
evolution, around a redshift of . We compute predicted stellar
masses for the GRB host galaxies using the prescription determined from QSO-DLA
samples and compare the measured stellar masses for the four hosts where
stellar masses have been determined from SED fits. We find excellent agreement
and conclude that, on basis of all available data and tests, long duration
GRB-DLA hosts and intervening QSO-DLAs are consistent with being drawn from the
same underlying population. GRB host galaxies and QSO-DLAs are found to have
different impact parameter distributions and we briefly discuss how this may
affect statistical samples. The impact parameter distribution has two effects.
First any metallicity gradient will shift the measured metallicity away from
the metallicity in the centre of the galaxy, second the path of the sightline
through different parts of the potential well of the dark matter halo will
cause different velocity fields to be sampled. We report evidence suggesting
that this second effect may have been detected.Comment: 11 pages, 6 figures, 6 tables. Accepted for publication in MNRAS Main
Journal. For the definitive version visit http://mnras.oxfordjournals.org
Standardization of Anaesthesia Ready Time and reasons of delay in induction of anaesthesia
Objective: Anaesthesia-Ready Time (ART) is the time taken by the anaesthetist to provide sufficient anaesthetic depth for start of surgery. Our aim was to set benchmark timings for ART and compare it with our current practice.Methods: Benchmark ART time of 15 minutes was set for American Society of Anesthesiologists (ASA) class I and II patients, 30 minutes for ASA III and IV patients, 20 minutes for spinal and 30 minutes for epidural anaesthesia. An additional 15 minutes was added for each invasive procedure.Results: Three hundred elective cases were audited. Seventy eight percent of the cases were within benchmark timings. The main causes of delay included undergraduate students performing procedures (24.6%), teaching invasive lines to postgraduates (21.3%) and paediatric patients (16.4%).CONCLUSION: The introduction of benchmark timings and its regular auditing can help standardize operating room booking time and reducing patient cost
The maintenance of elevated active chlorine levels in the Antarctic lower stratosphere through HCl null cycles
The Antarctic ozone hole arises from ozone destruction driven by elevated levels of ozone destroying ("active") chlorine in Antarctic spring. These elevated levels of active chlorine have to be formed first and then maintained throughout the period of ozone destruction. It is a matter of debate how this maintenance of active chlorine is brought about in Antarctic spring, when the rate of formation of HCl (considered to be the main chlorine deactivation mechanism in Antarctica) is extremely high. Here we show that in the heart of the ozone hole (16–18 km or 85–55 hPa, in the core of the vortex), high levels of active chlorine are maintained by effective chemical cycles (referred to as HCl null cycles hereafter). In these cycles, the formation of HCl is balanced by immediate reactivation, i.e. by immediate reformation of active chlorine. Under these conditions, polar stratospheric clouds sequester HNO3 and thereby cause NO2 concentrations to be low. These HCl null cycles allow active chlorine levels to be maintained in the Antarctic lower stratosphere and thus rapid ozone destruction to occur. For the observed almost complete activation of stratospheric chlorine in the lower stratosphere, the heterogeneous reaction HCl + HOCl is essential; the production of HOCl occurs via HO2 + ClO, with the HO2 resulting from CH2O photolysis. These results are important for assessing the impact of changes of the future stratospheric composition on the recovery of the ozone hole. Our simulations indicate that, in the lower stratosphere, future increased methane concentrations will not lead to enhanced chlorine deactivation (through the reaction CH4 + Cl  ⟶  HCl + CH3) and that extreme ozone destruction to levels below  ≈ 0.1 ppm will occur until mid-century
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