667 research outputs found
Powering a Biosensor Using Wearable Thermoelectric Technology
Wearable medical devices such as insulin pumps, glucose monitors, hearing aids, and electrocardiograms provide necessary medical aid and monitoring to millions of users worldwide. These battery powered devices require battery replacement and frequent charging that reduces the freedom and peace of mind of users. Additionally, the significant portion of the world without access to electricity is unable to use these medical devices as they have no means to power them constantly. Wearable thermoelectric power generation aims to charge these medical device batteries without a need for grid power.
Our team has developing a wristband prototype that uses body heat, ambient air, and heat sinks to create a temperature difference across thermoelectric modules thus generating ultra-low voltage electrical power. A boost converter is implemented to boost this voltage to the level required by medical device batteries. Our goal was to use this generated power to charge medical device batteries off-the-grid, increasing medical device user freedom and allowing medical device access to those without electricity. We successfully constructed a wearable prototype that generates the voltage required by an electrocardiogram battery; however, further thermoelectric module and heat dissipation optimization is necessary to generate sufficient current to charge the battery
Ad hominem attacks on scientists are just as likely to undermine public faith in research as legitimate empirical critiques
Media coverage attacking the character and trustworthiness of a scientist can diminish public faith in the research findings of that scientist. Ralph M. Barnes, Heather M. Johnston, Noah MacKenzie, Stephanie J. Tobin and Chelsea M. Taglang have investigated the degree to which such attacks do undermine trust in that scientist's research, and the relative impact of various types of ad hominem attacks. Perhaps surprisingly, purely ad hominem attacks, such as accusations of a financial conflict of interest, for example, prove just as effective in undermining public faith in research findings as direct criticism of the empirical foundations of a science claim
UGC 4599: A Photometric Study of the Nearest Hoag-Type Ring Galaxy
We present a photometric study of UGC 4599, a low-luminosity galaxy
superficially resembling Hoag's Object in that on sky survey images it appears
to be a complete ring surrounding a roundish core. The nature of the outer ring
of Hoag-type galaxies is still debated and may be related either to slow
secular evolution or to environmental processes, such as galaxy-galaxy
interactions. we show that in UGC 4599 (a) the nearly round central body
follows well an r^1/4 light profile almost all the way to the centre, (b) the
isophotes are strongly twisted with a sharp 45 deg transition at a radius of
r~6 arcsec, (c) the blue ring seems to have reached near-equilibrium
configuration with the central body, (d) the ring is actually composed of a
one-and-a-half turn spiral feature, and (e) one side of the spiral shows
conspicuous star formation in the form of at least nine HII regions, revealed
by their H_alpha emission. Based on the photometric data, together with HI
information from the literature, we characterize UGC 4599 as an elliptical-like
object surrounded by a luminous ring and a massive, extremely extended HI disc.
Given its observed properties, we rule out UGC 4599 as representing a late
phase in barred early-type galaxies evolution. We discuss the origin of UGC
4599 and conclude that this galaxy could be the result of a major interaction
between two gas-rich spiral galaxies that took place at least 5 Gyr ago.
However, deep optical imaging and a detailed stellar population analysis are
required to determine whether the large gas reservoir could have been accreted
directly from the intergalactic medium onto a pre-existing elliptical galaxy in
the early Universe. A detailed kinematical study will shed light on the exact
nature of the central body and the ring of UGC 4599.Comment: 14 pages, 6 figures and 5 tables. Accepted for publication in MNRAS.
The abstract is abridged compared to the published versio
Prix agricoles 1964.8 - Agricultural prices 1964.8
<p>Error bars indicate 95% confidence intervals.</p
Hoag's Object: Evidence for Cold Accretion onto an Elliptical Galaxy
(Abridged) We present new photometric and spectroscopic observations of the
famous Hoag's Object, a peculiar ring galaxy with a central roundish core. The
nature of Hoag's Object is still under controversial discussion. Previous
studies demonstrated that a major accretion event that took place at least 2-3
Gyr ago can account for the observational evidence. However, the role of
internal nonlinear mechanisms in forming the outer ring was not yet completely
ruled out. These new data, together with HI and optical information from the
literature, are used to demonstrate that Hoag's Object is a relatively isolated
system surrounded by a luminous quasi-spiral pattern and a massive, low-density
HI disc. The main stellar body is an old, mildly triaxial elliptical galaxy
with very high angular momentum. We review previous formation scenarios of
Hoag's Object in light of the new data and conclude that the peculiar
morphology could not represent a late phase in barred early-type galaxies
evolution. In addition, no observational evidence supports late merging events
in the evolution of the galaxy, although further tests are required before
safely dismissing this idea. We propose a new scenario where the elliptical
core formed in the early Universe with the HI disc forming shortly after the
core by prolonged "cold" accretion of primordial gas from the intergalactic
medium. The low gas density does not allow intense star formation to occur
everywhere in the disc, but only along a tightly wound spiral pattern of
enhanced density induced by the triaxial gravitational potential.Comment: 18 pages, 12 figures. MNRAS in press, minor changes to match
published versio
Diabetes screening with hemoglobin A1c prior to a change in guideline recommendations: prevalence and patient characteristics
<p>Abstract</p> <p>Background</p> <p>In January 2010, the American Diabetes Association recommended the use of hemoglobin A1c (Hgb A1c) to screen and diagnose diabetes. This study explored the prevalence and clinical context of Hgb A1c tests done for non-diabetic primary care patients for the three years prior to the release of the new guidelines. We sought to determine the provision of tests in non-diabetic patients age 19 or over, patients age 45 and over (eligible for routine diabetes screening), the annual change in the rate of this screening test, and the patient characteristics associated with the provision of Hgb A1c screening.</p> <p>Methods</p> <p>We conducted a retrospective study using data routinely collected in Electronic Medical Records. The participants were thirteen community-based family physicians in Toronto, Ontario. We calculated the proportion of non diabetic patients who had at least one Hbg A1c done in three years. We used logistic generalized estimating equation with year treated as a continuous variable to test for a non-zero slope in yearly Hbg A1c provision. We modelled screening using multivariable logistic regression.</p> <p>Results</p> <p>There were 11,792 non-diabetic adults. Of these, 1,678 (14.2%; 95%CI 13.6%-14.9%) had at least one Hgb A1c test done; this was higher for patients 45 years of age or older (20.2%; 95% CI 19.3% - 21.2%). The proportion of non-diabetic patients with an A1c test increased from 5.2% in 2007 to 8.8% in 2009 (p < 0.0001 for presence of slope). Factors associated with significantly greater adjusted odds ratios of having the test done included increasing diastolic blood pressure, increasing fasting glucose, increasing body mass index, increasing age, as well as male gender and presence of hypertension, but not smoking status or LDL cholesterol. Patients living in the highest income quintile neighbourhoods had significantly lower odds ratios of having this test done than those in the lowest quintile (p < 0.001).</p> <p>Conclusions</p> <p>A large and increasing proportion of the non-diabetic patients we studied have had an Hgb A1c for screening prior to guidelines recommending the test for this purpose. Several risk factors for cardiovascular disease or diabetes were associated with the provision of the Hgb A1c. Early uptake of the test may represent appropriate utilization.</p
Exoplanet Science Priorities from the Perspective of Internal and Surface Processes for Silicate and Ice Dominated Worlds
The geophysics of extrasolar planets is a scientific topic often regarded as
standing largely beyond the reach of near-term observations. This reality in no
way diminishes the central role of geophysical phenomena in shaping planetary
outcomes, from formation, to thermal and chemical evolution, to numerous issues
of surface and near-surface habitability. We emphasize that for a balanced
understanding of extrasolar planets, it is important to look beyond the natural
biases of current observing tools, and actively seek unique pathways to
understand exoplanet interiors as best as possible during the long interim
prior to a time when internal components are more directly accessible. Such
pathways include but are not limited to: (a) enhanced theoretical and numerical
modeling, (b) laboratory research on critical material properties, (c)
measurement of geophysical properties by indirect inference from imprints left
on atmospheric and orbital properties, and (d) the purpose-driven use of Solar
System object exploration expressly for its value in comparative planetology
toward exoplanet-analogs. Breaking down barriers that envision local Solar
System exploration, including the study of Earth's own deep interior, as
separate from and in financial competition with extrasolar planet research, may
greatly improve the rate of needed scientific progress for exoplanet
geophysics. As the number of known rocky and icy exoplanets grows in the years
ahead, we expect demand for expertise in 'exogeoscience' will expand at a
commensurately intense pace. We highlight key topics, including: how water
oceans below ice shells may dominate the total habitability of our galaxy by
volume, how free-floating nomad planets may often attain habitable subsurface
oceans supported by radionuclide decay, and how deep interiors may critically
interact with atmospheric mass loss via dynamo-driven magnetic fields
Highly Volcanic Exoplanets, Lava Worlds, and Magma Ocean Worlds:An Emerging Class of Dynamic Exoplanets of Significant Scientific Priority
Highly volcanic exoplanets, which can be variously characterized as 'lava
worlds', 'magma ocean worlds', or 'super-Ios' are high priority targets for
investigation. The term 'lava world' may refer to any planet with extensive
surface lava lakes, while the term 'magma ocean world' refers to planets with
global or hemispherical magma oceans at their surface. 'Highly volcanic
planets', including super-Ios, may simply have large, or large numbers of,
active explosive or extrusive volcanoes of any form. They are plausibly highly
diverse, with magmatic processes across a wide range of compositions,
temperatures, activity rates, volcanic eruption styles, and background
gravitational force magnitudes. Worlds in all these classes are likely to be
the most characterizable rocky exoplanets in the near future due to
observational advantages that stem from their preferential occurrence in short
orbital periods and their bright day-side flux in the infrared. Transit
techniques should enable a level of characterization of these worlds analogous
to hot Jupiters. Understanding processes on highly volcanic worlds is critical
to interpret imminent observations. The physical states of these worlds are
likely to inform not just geodynamic processes, but also planet formation, and
phenomena crucial to habitability. Volcanic and magmatic activity uniquely
allows chemical investigation of otherwise spectroscopically inaccessible
interior compositions. These worlds will be vital to assess the degree to which
planetary interior element abundances compare to their stellar hosts, and may
also offer pathways to study both the very young Earth, and the very early form
of many silicate planets where magma oceans and surface lava lakes are expected
to be more prevalent. We suggest that highly volcanic worlds may become second
only to habitable worlds in terms of both scientific and public long-term
interest.Comment: A white paper submitted in response to the National Academy of
Sciences 2018 Exoplanet Science Strategy solicitation, from the NASA Sellers
Exoplanet Environments Collaboration (SEEC) of the Goddard Space Flight
Center. 6 pages, 0 figure
PaLM: Scaling Language Modeling with Pathways
Large language models have been shown to achieve remarkable performance
across a variety of natural language tasks using few-shot learning, which
drastically reduces the number of task-specific training examples needed to
adapt the model to a particular application. To further our understanding of
the impact of scale on few-shot learning, we trained a 540-billion parameter,
densely activated, Transformer language model, which we call Pathways Language
Model PaLM. We trained PaLM on 6144 TPU v4 chips using Pathways, a new ML
system which enables highly efficient training across multiple TPU Pods. We
demonstrate continued benefits of scaling by achieving state-of-the-art
few-shot learning results on hundreds of language understanding and generation
benchmarks. On a number of these tasks, PaLM 540B achieves breakthrough
performance, outperforming the finetuned state-of-the-art on a suite of
multi-step reasoning tasks, and outperforming average human performance on the
recently released BIG-bench benchmark. A significant number of BIG-bench tasks
showed discontinuous improvements from model scale, meaning that performance
steeply increased as we scaled to our largest model. PaLM also has strong
capabilities in multilingual tasks and source code generation, which we
demonstrate on a wide array of benchmarks. We additionally provide a
comprehensive analysis on bias and toxicity, and study the extent of training
data memorization with respect to model scale. Finally, we discuss the ethical
considerations related to large language models and discuss potential
mitigation strategies
- …