1,893 research outputs found
Advance Care Planning Documentation at Mad River Family Practice
Advance care planning is a powerful tool that helps to guide clinicians and family members to make care decisions that align with a patients values when that patient is unable to speak for themselves. Advance care planning documents such as advance directives are the primary tool used to put these patient preferences in writing, but there is little information about the true rates of document completion in Vermont. This project was focused on determining how many patients at the Mad River Family Practice had advance care planning documents, developing a tracking tool in the electronic medical record to see trends in document completion among panel patients over time, and identify strategies to increase engagement in advance care planning at the practice.https://scholarworks.uvm.edu/fmclerk/1989/thumbnail.jp
Improving Patient Safety through Structural Empowerment.
D.N.P. Thesis. University of Hawaiʻi at Mānoa 2017
Aluminum-26 Enrichment in the Surface of Protostellar Disks Due to Protostellar Cosmic Rays
The radioactive decay of aluminum-26 (Al) is an important heating
source in early planet formation. Since its discovery, there have been several
mechanisms proposed to introduce Al into protoplanetary disks, primarily
through contamination by external sources. We propose a local mechanism to
enrich protostellar disks with Al through irradiation of the
protostellar disk surface by cosmic rays accelerated in the protostellar
accretion shock. We calculate the Al enrichment, [Al/Al],
at the surface of the protostellar disk in the inner AU throughout the
evolution of low-mass stars, from M-dwarfs to proto-Suns. Assuming constant
mass accretion rates, , we find that irradiation by MeV cosmic rays
can provide significant enrichment on the disk surface if the cosmic rays are
not completely coupled to the gas in the accretion flow. Importantly, we find
that low accretion rates, M yr, are able
to produce canonical amounts of Al, . These accretion rates are experienced at the
transition from Class I- to Class II-type protostars, when it is assumed that
calcium-aluminum-rich inclusions condense in the inner disk. We conclude that
irradiation of the inner disk surface by cosmic ray protons accelerated in
accretion shocks at the protostellar surface may be an important mechanism to
produce Al. Our models show protostellar cosmic rays may be a viable
model to explain the enrichment of Al found in the Solar System.Comment: Accepted to ApJ, in pres
Probing 3D Density and Velocity Fields of ISM in Centers of Galaxies with Future X-Ray Observations
Observations of bright and variable "reflected" X-ray emission from molecular
clouds located within inner hundred parsec of our Galaxy have demonstrated that
the central supermassive black hole, Sgr A*, experienced short and powerful
flares in the past few hundred years. These flares offer a truly unique
opportunity to determine 3D location of the illuminated clouds (with ~10 pc
accuracy) and to reveal their internal structure (down to 0.1 pc scales). Short
duration of the flare(s), combined with X-rays high penetration power and
insensitivity of the reflection signal to thermo- and chemo-dynamical state of
the gas, ensures that the provided diagnostics of the density and velocity
fields is unbiased and almost free of the projection and opacity effects. Sharp
and sensitive snapshots of molecular gas accessible with aid of future X-ray
observatories featuring large collecting area and high angular (arcsec-level)
and spectral (eV-level) resolution cryogenic bolometers will present invaluable
information on properties of the supersonic turbulence inside the illuminated
clouds, map their shear velocity field and allow cross-matching between X-ray
data and velocity-resolved emission of various molecular species provided by
ALMA and other ground-based facilities. This will highlight large and
small-scale dynamics of the dense gas and help uncovering specifics of the ISM
lifecycle and high-mass star formation under very extreme conditions of
galactic centers. While the former is of particular importance for the SMBH
feeding and triggering AGN feedback, the latter might be an excellent test case
for star formation taking place in high-redshift galaxies.Comment: White paper submitted to the Astro2020 Decadal Surve
Methanation of CO over Ni catalyst: A theoretical study
Theoretical methods (generalized valence‐bond calculations) were used to examine the bond energies and geometries of numerous species chemisorbed onto Ni clusters representing Ni surface. These results were used to obtain thermochemical information and to examine various mechanisms for the methanation of CO over Ni: CO+3H^(→)_(2(Ni)) CH_4+H_2O. It is found that chemisorbed formyl radicals (Ni–CHO) lead to a favorably appearing chain reaction that is consistent with current experimental results. In addition, we find a chemisorbed C_2 species that may be the catalytically active C_(ad) formed from dissociation of CO
The influence of the turbulent perturbation scale on prestellar core fragmentation and disk formation
The collapse of weakly turbulent prestellar cores is a critical stage in the
process of star formation. Being highly non-linear and stochastic, the outcome
of collapse can only be explored theoretically by performing large ensembles of
numerical simulations. Standard practice is to quantify the initial turbulent
velocity field in a core in terms of the amount of turbulent energy (or some
equivalent) and the exponent in the power spectrum (n \equiv -d log Pk /d log
k). In this paper, we present a numerical study of the influence of the details
of the turbulent velocity field on the collapse of an isolated, weakly
turbulent, low-mass prestellar core. We show that, as long as n > 3 (as is
usually assumed), a more critical parameter than n is the maximum wavelength in
the turbulent velocity field, {\lambda}_MAX. This is because {\lambda}_MAX
carries most of the turbulent energy, and thereby influences both the amount
and the spatial coherence of the angular momentum in the core. We show that the
formation of dense filaments during collapse depends critically on
{\lambda}_MAX, and we explain this finding using a force balance analysis. We
also show that the core only has a high probability of fragmenting if
{\lambda}_MAX > 0.5 R_CORE (where R_CORE is the core radius); that the dominant
mode of fragmentation involves the formation and break-up of filaments; and
that, although small protostellar disks (with radius R_DISK <= 20 AU) form
routinely, more extended disks are rare. In turbulent, low-mass cores of the
type we simulate here, the formation of large, fragmenting protostellar disks
is suppressed by early fragmentation in the filaments.Comment: 11 pages, 7 figures; accepted for publication by MNRA
Expression of a catalytically inactive mutant form of glutathione peroxidase 4 (Gpx4) confers a dominant-negative effect in male fertility.
The selenoenzyme Gpx4 is essential for early embryogenesis and cell viability for its unique function to prevent phospholipid oxidation. Recently, the cytosolic form of Gpx4 was identified as an upstream regulator of a novel form of non-apoptotic cell death, called ferroptosis, whereas the mitochondrial isoform of Gpx4 (mGpx4) was previously shown to be crucial for male fertility. Here, we generated and analyzed mice with targeted mutation of the active site selenocysteine (Sec) of Gpx4 (Gpx4_U46S). Mice homozygous for Gpx4_U46S died at the same embryonic stage (E7.5) as Gpx4-/- embryos as expected. Surprisingly, male mice heterozygous for Gpx4_U46S presented subfertility. Subfertility was manifested in a reduced number of litters from heterozygous breedings and an impairment of spermatozoa to fertilize oocytes in vitro. Morphologically, sperm isolated from heterozygous Gpx4_U46S mice revealed many structural abnormalities particularly in the spermatozoan midpiece due to improper oxidation and polymerization of sperm capsular proteins and malformation of the mitochondrial capsule surrounding and stabilizing sperm mitochondria. These findings are reminiscent of sperm isolated from selenium-deprived rodents or from mice specifically lacking mGpx4. Due to a strongly facilitated incorporation of Ser in the polypeptide chain as compared to Sec at the UGA codon, expression of the catalytically inactive Gpx4_U46S was found to be strongly increased. Since the stability of the mitochondrial capsule of mature spermatozoa depends on the moonlighting function of Gpx4 both as an enzyme oxidizing capsular protein thiols and being a structural protein, tightly controlled expression of functional Gpx4 emerges being key for full male fertility
Influence of surgical approach on functional outcome in reverse shoulder arthroplasty
SummaryIntroductionReverse shoulder arthroplasties (RSA) can be performed using a Deltopectoral (DP) or alternatively a Transdeltoid (TD) approach.HypothesisAlthough the humeral cut is lower by TD approach, this should not affect postoperative functional results.Material and methodsThis retrospective multicentric study evaluated the complete medical records of RSA implanted between October 2003 and December 2008. Inclusion criteria were: follow-up of at least 1year, a complete file including a comparative radiological work-up making it possible to analyze eventual arm and humeral lengthening. Evaluation of postoperative function was based on Active Anterior Elevation (AAE).ResultsWe studied 144 RSA in 142 patients. One hundred and nine RSA were implanted by the DP approach and 35 by the TD approach. Mean lengthening of the humerus compared to the controlateral side by DP approach was 0.5±1.3cm while there was a mean shortening of −0.5±1.0cm by TD approach (P<0.001). The difference in cut was partially compensated by using thicker polyethylene inserts with the TD approach. Mean arm lengthening compared to the controlateral side was 1.7±1.7cm by DP approach and 1.2±1.4cm by TD approach (mean difference 0.5cm; (95% CI −0.1; 1.2). AAE for RSA by DP approach was 145±22° and 135±29° by TD approach (mean difference 10°, 95% CI −1; 21).DiscussionRSA results in improved AAE because of restored deltoid tension and an increase in the deltoid lever arm. The humeral cut by TD is lower, but this was partially corrected in this study by the use of thicker polyethylene inserts. Nevertheless there is no significant clinical difference in postoperative function between the two approaches.Level of EvidenceLevel IV. Retrospective therapeutic study
Using Machine Learning to estimate the technical potential of shallow ground-source heat pumps with thermal interference
The increasing use of ground-source heat pumps (GSHPs) for heating and cooling of buildings raises questions regarding the technical potential of GSHPs and their impact on the temperature in the shallow subsurface. In this paper, we develop a method using Machine Learning to estimate the technical potential of shallow GSHPs, which enables such an estimation for Switzerland with limited data and computational resources. A training dataset is constructed based on meteorological and geological data across Switzerland. We analyse correlations and the importance of each of the input data for estimating the GSHP potential and compare different input feature sets and Machine Learning models. The Random Forest algorithm, trained on the full dataset, provides the best performance to estimate the GSHP potential. The resulting model yields an R2 score of 0.95 for the annual energy potential, 0.86 for the heat extraction rate, and 0.82 for the potential number of boreholes per GSHP system
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