6,939 research outputs found
Influence of material quality and process-induced defects on semiconductor device performance and yield
An overview of major causes of device yield degradation is presented. The relationships of device types to critical processes and typical defects are discussed, and the influence of the defect on device yield and performance is demonstrated. Various defect characterization techniques are described and applied. A correlation of device failure, defect type, and cause of defect is presented in tabular form with accompanying illustrations
Type 2 diabetes in Tirana City, Albania: a rapid increase in a country in transition.
AIMS: To determine how the prevalence of Type 2 diabetes mellitus has changed in Tirana, the capital of Albania, over 20 years. METHODS: Cluster sampling was used to select 700 households including 1540 adults 25 years of age and over in Tirana City, Albania in 2001. RESULTS: Of 1540 potential subjects, 1120 participated (response rate 72.7%). Using the 1985 WHO criteria to provide comparability with earlier data, the overall prevalence of Type 2 diabetes mellitus in the age group 25+ was 6.3% (95% confidence interval 4.8-7.7); 6.9% (4.8-9.1%) male; 5.6% (3.8-7.5%) female. The age-adjusted prevalence in those aged 25+ was 5.4%. Of respondents, 3.4% were known to have diabetes, and 2.9% were newly identified through the survey. The prevalence of diabetes increased with age, although among men there was a slight decline after age 65. Impaired glucose tolerance was found in a further 2.9% of respondents, again increasing with age. The prevalence of diabetes has increased significantly since 1980, doubling in the age group 50+. Use of the 1999 WHO diagnostic criteria produces a higher unadjusted prevalence, at 9.7% (8-11.4%). In a logistic regression model, obesity and family history were independent determinants of the probability of having diabetes. Among those known to have diabetes, control was poor. CONCLUSIONS: The prevalence of diabetes in Albania has increased rapidly, consistent with what has been seen in other countries undergoing rapid modernization. It is likely to increase further in the future, with important implications for health policy
Are there disciplinary differences in writing about pornography? A trialogue for two voices
© 2018 Informa UK Limited, trading as Taylor & Francis Group. In 2016, Professors Alan McKee (a humanities researcher) and Roger Ingham (a psychology researcher) submitted a successful grant application for a project entitled âPornography's Effects on Audiences: Explaining Contradictory Research Dataâ (DP170100808). We were approached by Feona Attwood, who knew of the grant and asked whether we could provide a piece for this special issue that explored âwriting about porn across disciplinesâ. The process of writing the grant application had already provided plenty of rich data about differences in disciplinary vocabularies and the ways in which various words implied different objects of study and different relationships to objects of study. Rather than trying to hide these differences we decided to make them the focus of the article. This piece presents three voicesâAlan (AM), Roger (RI) and the original grant application (GA)âin trialogue, as a tentative beginning to the exploration of some potential differences between academic disciplines in conceptualizing, researching and writing about pornography
Similarities and contrasts in tectonic and volcanic style and history along the Colorado plateaus-to-basin and range transition zone in Western Arizona: Geologic framework for tertiary extensional tectonics
The overall temporal and spatial relations between middle Tertiary volcanism and tectonism from the Basin and Range province onto the edge of the Colorado Plateaus province suggest that a single magnetic-tectonic episode affected the entire region more or less simultaneously during this period. The episode followed a post-Laramide (late Eocene through Oligocene) period of 25 million years of relative stability. Middle Tertiary volcanism did not migrate gradually eastward in a simple fashion onto the Colorado Plateau. In fact, late Oligocene volcanism appears to be more voluminous near the Aquarius Mountains than throughout the adjacent Basin and Range province westward to the Colorado River. Any model proposed to explain the cause of extension and detachment faulting in the eastern part of the Basin and Range province must consider that the onset of volcanism appears to have been approximately synchronous from the Colorado River region of the Basin and Range across the transition zone and onto the edge of the Colorado Plateaus
Bipolar molecular outflows driven by hydromagnetic protostellar winds
We demonstrate that magnetically-collimated protostellar winds will sweep
ambient material into thin, radiative, momentum-conserving shells whose
features reproduce those commonly observed in bipolar molecular outflows. We
find the typical position-velocity and mass-velocity relations to occur in
outflows in a wide variety of ambient density distributions, regardless of the
time histories of their driving winds.Comment: 4 pages, 1 figure, submitted to ApJ
Molecular Line Emission from Massive Protostellar Disks: Predictions for ALMA and the EVLA
We compute the molecular line emission of massive protostellar disks by
solving the equation of radiative transfer through the cores and disks produced
by the recent radiation-hydrodynamic simulations of Krumholz, Klein, & McKee.
We find that in several representative lines the disks show brightness
temperatures of hundreds of Kelvin over velocity channels ~10 km s^-1 wide,
extending over regions hundreds of AU in size. We process the computed
intensities to model the performance of next-generation radio and submillimeter
telescopes. Our calculations show that observations using facilities such as
the EVLA and ALMA should be able to detect massive protostellar disks and
measure their rotation curves, at least in the nearest massive star-forming
regions. They should also detect significant sub-structure and non-axisymmetry
in the disks, and in some cases may be able to detect star-disk velocity
offsets of a few km s^-1, both of which are the result of strong gravitational
instability in massive disks. We use our simulations to explore the strengths
and weaknesses of different observational techniques, and we also discuss how
observations of massive protostellar disks may be used to distinguish between
alternative models of massive star formation.Comment: 15 pages, 9 figures, emulateapj format, accepted for publication in
ApJ. Resolution of figures severely degraded to fit within size limits.
Download the full paper from
http://www.astro.princeton.edu/~krumholz/recent.htm
Photoionization of Galactic Halo Gas by Old Supernova Remnants
We present new calculations on the contribution from cooling hot gas to the
photoionization of warm ionized gas in the Galaxy. We show that hot gas in
cooling supernova remnants (SNRs) is an important source of photoionization,
particularly for gas in the halo. We find that in many regions at high latitude
this source is adequate to account for the observed ionization so there is no
need to find ways to transport stellar photons from the disk. The flux from
cooling SNRs sets a floor on the ionization along any line of sight. Our model
flux is also shown to be consistent with the diffuse soft X-ray background and
with soft X-ray observations of external galaxies.
We consider the ionization of the clouds observed towards the halo star HD
93521, for which there are no O stars close to the line of sight. We show that
the observed ionization can be explained successfully by our model EUV/soft
X-ray flux from cooling hot gas. In particular, we can match the H alpha
intensity, the S++/S+ ratio, and the C+* column. From observations of the
ratios of columns of C+* and either S+ or H0, we are able to estimate the
thermal pressure in the clouds. The slow clouds require high (~10^4 cm^-3 K)
thermal pressures to match the N(C+*)/N(S+) ratio. Additional heating sources
are required for the slow clouds to maintain their ~7000 K temperatures at
these pressures, as found by Reynolds, Hausen & Tufte (1999).Comment: AASTeX 5.01; 34 pages, 2 figures; submitted to Astrophysical Journa
How Protostellar Outflows Help Massive Stars Form
We consider the effects of an outflow on radiation escaping from the
infalling envelope around a massive protostar. Using numerical radiative
transfer calculations, we show that outflows with properties comparable to
those observed around massive stars lead to significant anisotropy in the
stellar radiation field, which greatly reduces the radiation pressure
experienced by gas in the infalling envelope. This means that radiation
pressure is a much less significant barrier to massive star formation than has
previously been thought.Comment: 4 pages, 2 figures, emulateapj, accepted for publication in ApJ
Letter
A physical interpretation of the jet-like X-ray emission from supernova remnant W49B
In the framework of the study of supernova remnants and their complex
interaction with the interstellar medium and the circumstellar material, we
focus on the galactic supernova remnant W49B. Its morphology exhibits an X-ray
bright elongated nebula, terminated on its eastern end by a sharp perpendicular
structure aligned with the radio shell. The X-ray spectrum of W49B is
characterized by strong K emission lines from Si, S, Ar, Ca, and Fe. There is a
variation of the temperature in the remnant with the highest temperature found
in the eastern side and the lowest one in the western side. The analysis of the
recent observations of W49B indicates that the remnant may be the result of an
asymmetric bipolar explosion where the ejecta are collimated along a jet-like
structure and the eastern jet is hotter and more Fe-rich than the western one.
Another possible scenario associates the X-ray emission with a spherical
explosion where parts of the ejecta are interacting with a dense belt of
ambient material. To overcome this ambiguity we present new results of the
analysis of an XMM-Newton observation and we perform estimates of the mass and
energy of the remnant. We conclude that the scenario of an anisotropic jet-like
explosion explains quite naturally our observation results, but the association
of W49B with a hypernova and a gamma-ray burst, although still possible, is not
directly supported by any evidence.Comment: 7 pages, 5 figures, accepted for publication in Advances in Space
Researc
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