878 research outputs found
Collaboration Versus Cheating
We outline how we detected programming plagiarism in an introductory online
course for a master's of science in computer science program, how we achieved a
statistically significant reduction in programming plagiarism by combining a
clear explanation of university and class policy on academic honesty reinforced
with a short but formal assessment, and how we evaluated plagiarism rates
before SIGand after implementing our policy and assessment.Comment: 7 pages, 1 figure, 5 tables, SIGCSE 201
Chemical abundances of the metal-poor horizontal-branch stars CS 22186-005 and CS 30344-033
We report on a chemical-abundance analysis of two very metal-poor
horizontal-branch stars in the Milky Way halo: CS 22186-005 ([Fe/H]=-2.70) and
CS 30344-033 ([Fe/H]=-2.90). The analysis is based on high-resolution spectra
obtained at ESO, with the spectrographs HARPS at the 3.6 m telescope, and UVES
at the VLT. We adopted one-dimensional, plane-parallel model atmospheres
assuming local thermodynamic equilibrium. We derived elemental abundances for
13 elements for CS 22186-005 and 14 elements for CS 30344-033. This study is
the first abundance analysis of CS 30344-033. CS 22186-005 has been analyzed
previously, but we report here the first measurement of nickel (Ni; Z = 28) for
this star, based on twenty-two NiI lines ([Ni/Fe]=-0.210.02); the
measurement is significantly below the mean found for most metal-poor stars.
Differences of up to 0.5 dex in [Ni/Fe] ratios were determined by different
authors for the same type of stars in the literature, which means that it is
not yet possible to conclude that there is a real intrinsic scatter in the
[Ni/Fe] ratios. For the other elements for which we obtained estimates, the
abundance patterns in these two stars match the Galactic trends defined by
giant and turnoff stars well. This confirms the value of horizontal-branch
stars as tracers of the chemical properties of stellar populations in the
Galaxy. Our radial velocities measurements for CS 22186-005 differ from
previously published measurements by more than the expected statistical errors.
More measurements of the radial velocity of this star are encouraged to confirm
or refute its radial velocity variability
Low dark current and high speed ZnO metalâsemiconductorâmetal photodetector on SiO2/Si substrate
Cataloged from PDF version of article.ZnO thin films are deposited by radio-frequency magnetron sputtering on thermally grown SiO2 on Si substrates. Pt/Au contacts are fabricated by standard photolithography and lift-off in order to form a metal-semiconductor-metal (MSM) photodetector. The dark current of the photodetector is measured as 1 pA at 100V bias, corresponding to 100 pA/cm(2) current density. Spectral photoresponse measurement showed the usual spectral behavior and 0.35 A/W responsivity at a 100V bias. The rise and fall times for the photocurrent are measured as 22 ps and 8 ns, respectively, which are the lowest values to date. Scanning electron microscope image shows high aspect ratio and dense grains indicating high surface area. Low dark current density and high speed response are attributed to high number of recombination centers due to film morphology, deducing from photoluminescence measurements. These results show that as deposited ZnO thin film MSM photodetectors can be used for the applications needed for low light level detection and fast operation. (C) 2014 AIP Publishing LLC
Diabetic Foot Due to Anaphylactic Shock: A Case Report
Introduction: Diabetic foot is a clinical disorder, which is commonly seen in patients with diabetes mellitus. It is also the major cause of below knee amputation in the world. There are many underlying causes such as neuropathic, ischemic, and infectious causes for diabetic foot. Local or systemic complications may develop after snake bite.
Case Presentation: We reported a very rare case, involving a 78-year-old male admitted to the Emergency Department, who developed anaphylactic shock and diabetic foot after the snake bite.
Conclusions: Reviewing the literature, this is the second reported case of snake bite associated with diabetic foot
Weaning from inotropic support and concomitant beta-blocker therapy in severely ill heart failure patients:Take the time in order to improve prognosis
Arthropod diversity in pure oak forests of coppice origin in northern Thrace (Turkey)
Oak (Quercus spp.) forests are among the most important forest types in Turkey. In the past, oak forests were managed through coppice clear-cutting, but in recent decades they have mostly been converted to high forest. This study was aimed at explaining how arthropod diversity is affected during conversion from coppice to high oak forest and during the early stages of coppice succession. We tested the hypothesis that arthropod richness, abundance and diversity in coppice oak sites varied according to stand age and a number of other forest characteristics. Arthropod communities were sampled in 50 plots using four different methods: pitfall traps, sweep nets, sticky cards and cloth shaking. A total of 13 084 individuals were collected and classified into 193 Recognizable Taxonomic Units (RTUs), with the most RTUs and the greatest number of specimens captured by sweep netting. We identified 17 taxa within RTUâs with more than 1% of the captured arthropods, which constituted 75% of the total specimens. The number of RTUs varied significantly according to trap type. Arthropod richness and Shannon-Wiener biodiversity index (HâČ) increased with elevation and precipitation. In young (1-40 yrs-old) and middle-aged (41-80 yrs) stands, arthropod biodiversity was not significantly affected by stand type, but slightly increased with diameter at breast height and tree height. Forest characteristics, such as the litter layer, understory and crown diameter, weakly influenced arthropod richness and abundance. Cluster analysis revealed that stand types and trap types differed taxonomically. Principal component analysis showed that stand types were clearly separated by the stand parameters measured. Insect families (Formicidae, Thripidae, Lygaeidae, Dolichopodidae, Luaxanidae, Cicadellidae and Ichneumonidae) could potentially be used as indicators of coppice oak conditions. As the coppice oak changes to mature forest, further studies are needed to better assess the relation between arthropods, forest types and structural characteristics of stands
Evaluation of patients with a HeartMate 3 left ventricular assist device using echocardiographic particle image velocimetry
The HgMn Binary Star Phi Herculis: Detection and Properties of the Secondary and Revision of the Elemental Abundances of the Primary
Observations of the Mercury-Manganese star Phi Herculis with the Navy
Prototype Optical Interferometer (NPOI) conclusively reveal the previously
unseen companion in this single-lined binary system. The NPOI data were used to
predict a spectral type of A8V for the secondary star Phi Her B. This
prediction was subsequently confirmed by spectroscopic observations obtained at
the Dominion Astrophysical Observatory. Phi Her B is rotating at 50 +/-3
km/sec, in contrast to the 8 km/sec lines of Phi Her A. Recognizing the lines
from the secondary permits one to separate them from those of the primary. The
abundance analysis of Phi Her A shows an abundance pattern similar to those of
other HgMn stars with Al being very underabundant and Sc, Cr, Mn, Zn, Ga, Sr,
Y, Zr, Ba, Ce, and Hg being very overabundant.Comment: Accepted to ApJ, 45 pages, 11 figure
Pectus Excavatum and Risk of Right Ventricular Failure in Left Ventricular Assist Device Patients
Background: Right ventricular failure (RVF) is a significant cause of morbidity and mortality in patients with a left ventricular assist device (LVAD). This study is aimed to investigate the influence of a pectus excavatum on early and late outcomes, specifically RVF, following LVAD implantation. Methods: A retrospective study was performed, that included patients with a HeartMate 3 LVAD at our tertiary referral center. The Haller index (HI) was calculated using computed tomography (CT) scan to evaluate the chest-wall dimensions. Results: In total, 80 patients (median age 57 years) were included. Two cohorts were identified: 28 patients (35%) with a normal chest wall (HI <2.0) and 52 patients (65%) with pectus excavatum (HI 2.0-3.2), with a mean follow-up time of 28 months. Early (<30 days) RVF and early acute kidney injury events did not differ between cohorts. Overall survival did not differ between cohorts with a hazard ratio (HR) of 0.47 (95% confidence interval (CI): 0.19-1.19, p = 0.113). Late (>30 days) recurrent readmission for RVF occurred more often in patients with pectus excavatum (p = 0.008). The onset of late RVF started around 18 months after implantation and increased thereafter in the overall study cohort.Conclusions: Pectus excavatum is observed frequently in patients with a LVAD implantation. These patients have an increased rate of readmissions and late RVF. Further investigation is required to explore the extent and severity of chest-wall abnormalities on the risk of RVF.</p
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