204 research outputs found
Shifts in the architecture of the Nationwide Health Information Network
In the midst of a US $30 billion USD investment in the Nationwide Health Information Network (NwHIN) and electronic health records systems, a significant change in the architecture of the NwHIN is taking place. Prior to 2010, the focus of information exchange in the NwHIN was the Regional Health Information Organization (RHIO). Since 2010, the Office of the National Coordinator (ONC) has been sponsoring policies that promote an internet-like architecture that encourages point to-point information exchange and private health information exchange networks. The net effect of these activities is to undercut the limited business model for RHIOs, decreasing the likelihood of their success, while making the NwHIN dependent on nascent technologies for community level functions such as record locator services. These changes may impact the health of patients and communities. Independent, scientifically focused debate is needed on the wisdom of ONC's proposed changes in its strategy for the NwHIN
dGEMRIC as a function of BMI
SummaryObjectiveDelayed gadolinium-enhanced MRI of cartilage (dGEMRIC) reflects cartilage glycosaminoglycan (GAG) distribution. The technique assumes that the plasma levels of the contrast agent Gd-DTPA2â are the same across individuals after intravenous (IV) injection, when dosing by weight. However, adipose tissue has lower extracellular water (ECW) than lean tissue. The aims of this study were to measure (1) plasma Gd-DTPA2â levels vs body mass index (BMI), and (2) dGEMRIC vs BMI after correcting for the doseâBMI effect.Method(1) Plasma Gd-DTPA2â levels were analyzed at 3â90min after IV injection per body weight in 24 individuals with BMI between 21.5 and 46.5. (2) dGEMRIC was compared with BMI in 19 asymptomatic volunteers and 23 with osteoarthritis (OA).Results(1) Plasma Gd-DTPA2â kinetics were similar in obese and non-obese groups, however, overall concentration was higher in the obese group. A very obese subject (BMI 45) would have 1.4 times higher Gd-DTPA2â concentration than a lean subject (BMI 20), which translates into a bias in dGEMRIC of up to 20%. (2) With dose bias taken into account, dGEMRIC showed no correlation with BMI in asymptomatic knees. In OA knees, unnarrowed femoral compartments demonstrated a negative correlation between dGEMRIC and BMI (R=0.57, P=0.004). No correlation was seen in radiographically narrowed compartments.ConclusionBMI can be a source of dosing bias in dGEMRIC and a correction factor should be considered in cross-sectional studies with a large range of BMI. There is no correlation between dGEMRIC and BMI in asymptomatic knees, but a negative correlation in OA knees
Vaccine message framing and parents' intent to immunize their infants for MMR
BACKGROUND AND OBJECTIVE: Emphasizing societal benefits of vaccines has been linked to increased vaccination intentions in adults. It is unclear if this pattern holds for parents deciding whether to vaccinate their children. The objective was to determine whether emphasizing the benefits of measles-mumps-rubella (MMR) vaccination directly to the vaccine recipient or to society differentially impacts parents' vaccine intentions for their infants.
METHODS: In a national online survey, parents (N = 802) of infants <12 months old were randomly assigned to receive 1 of 4 MMR vaccine messages: (1) the Centers for Disease Control and Prevention Vaccine Information Statement (VIS), (2) VIS and information emphasizing the MMR vaccine's benefits to the child, (3) VIS and information emphasizing societal benefits, or (4) VIS and information emphasizing benefits both to the child and society. Parents reported their likelihood of vaccinating their infants for MMR on a response scale of 0 (extremely unlikely) to 100 (extremely likely).
RESULTS: Compared with the VIS-only group (mean intention = 86.3), parents reported increased vaccine intentions for their infants when receiving additional information emphasizing the MMR vaccine's benefits either directly to the child (mean intention = 91.6, P = .01) or to both the child and society (mean intention = 90.8, P = .03). Emphasizing the MMR vaccine's benefits only to society did not increase intentions (mean intention = 86.4, P = .97).
CONCLUSIONS: We did not see increases in parents' MMR vaccine intentions for their infants when societal benefits were emphasized without mention of benefits directly to the child. This finding suggests that providers should emphasize benefits directly to the child. Mentioning societal benefits seems to neither add value to, nor interfere with, information highlighting benefits directly to the child
Renormalization Group Invariance of Exact Results in Supersymmetric Gauge Theories
We clarify the notion of Wilsonian renormalization group (RG) invariance in
supersymmetric gauge theories, which states that the low-energy physics can be
kept fixed when one changes the ultraviolet cutoff, provided appropriate
changes are made to the bare coupling constants in the Lagrangian. We first
pose a puzzle on how a quantum modified constraint (such as Pf(Q^i Q^j) =
\Lambda^{2(N+1)} in SP(N) theories with N+1 flavors) can be RG invariant, since
the bare fields Q^i receive wave function renormalization when one changes the
ultraviolet cutoff, while we naively regard the scale \Lambda as RG invariant.
The resolution is that \Lambda is not RG invariant if one sticks to canonical
normalization for the bare fields as is conventionally done in field theory. We
derive a formula for how \Lambda must be changed when one changes the
ultraviolet cutoff. We then compare our formula to known exact results and show
that their consistency requires the change in \Lambda we have found. Finally,
we apply our result to models of supersymmetry breaking due to quantum modified
constraints. The RG invariance helps us to determine the effective potential
along the classical flat directions found in these theories. In particular, the
inverted hierarchy mechanism does not occur in the original version of these
models.Comment: LaTeX, 26 page
Instanton Calculus and Nonperturbative Relations in N=2 Supersymmetric Gauge Theories
Using instanton calculus we check, in the weak coupling region, the
nonperturbative relation =i\pi\left(\cf-{a\over 2}
{\partial\cf\over\partial a}\right) obtained for a N=2 globally
supersymmetric gauge theory. Our computations are performed for instantons of
winding number k, up to k=2 and turn out to agree with previous nonperturbative
results.Comment: 18 pages, latex file, no figure
INSTANTON CALCULATIONS VERSUS EXACT RESULTS IN 4 DIMENSIONAL SUSY GAUGE THEORIES.
We relate the non-perturbative exact results in supersymmetry to perturbation
theory using several different methods: instanton calculations at weak or
strong coupling, a method using gaugino condensation and another method
relating strong and weak coupling. This allows many precise numerical checks of
the consistency of these methods, especially the amplitude of instanton
effects, and of the network of exact solutions in supersymmetry. However, there
remain difficulties with the instanton computations at strong coupling.Comment: 17 pages, uses harvmac
Microarray analysis of E9.5 reduced folate carrier (RFC1; Slc19a1) knockout embryos reveals altered expression of genes in the cubilin-megalin multiligand endocytic receptor complex
<p>Abstract</p> <p>Background</p> <p>The reduced folate carrier (<it>RFC1</it>) is an integral membrane protein and facilitative anion exchanger that mediates delivery of 5-methyltetrahydrofolate into mammalian cells. Adequate maternal-fetal transport of folate is necessary for normal embryogenesis. Targeted inactivation of the murine <it>RFC1 </it>gene results in post-implantation embryolethality, but daily folic acid supplementation of pregnant dams prolongs survival of homozygous embryos until mid-gestation. At E10.5 <it>RFC1</it><sup>-/- </sup>embryos are developmentally delayed relative to wildtype littermates, have multiple malformations, including neural tube defects, and die due to failure of chorioallantoic fusion. The mesoderm is sparse and disorganized, and there is a marked absence of erythrocytes in yolk sac blood islands. The identification of alterations in gene expression and signaling pathways involved in the observed dysmorphology following inactivation of RFC1-mediated folate transport are the focus of this investigation.</p> <p>Results</p> <p>Affymetrix microarray analysis of the relative gene expression profiles in whole E9.5 <it>RFC1</it><sup>-/- </sup>vs. <it>RFC1</it><sup>+/+ </sup>embryos identified 200 known genes that were differentially expressed. Major ontology groups included transcription factors (13.04%), and genes involved in transport functions (ion, lipid, carbohydrate) (11.37%). Genes that code for receptors, ligands and interacting proteins in the cubilin-megalin multiligand endocytic receptor complex accounted for 9.36% of the total, followed closely by several genes involved in hematopoiesis (8.03%). The most highly significant gene network identified by Ingenuityâą Pathway analysis included 12 genes in the cubilin-megalin multiligand endocytic receptor complex. Altered expression of these genes was validated by quantitative RT-PCR, and immunohistochemical analysis demonstrated that megalin protein expression disappeared from the visceral yolk sac of <it>RFC1</it><sup>-/- </sup>embryos, while cubilin protein was widely misexpressed.</p> <p>Conclusion</p> <p>Inactivation of <it>RFC1 </it>impacts the expression of several ligands and interacting proteins in the cubilin-amnionless-megalin complex that are involved in the maternal-fetal transport of folate and other nutrients, lipids and morphogens such as sonic hedgehog (Shh) and retinoids that play critical roles in normal embryogenesis.</p
The Surgeon General\u27s Facing Addiction Report: An Historic Document for Healthcare
The publication of Facing Addiction in America: The Surgeon General\u27s Report on Alcohol, Drugs, and Health presents an historic moment not only for the field of addiction medicine, but also for the United States as a nation. The Board of Directors of the Association for Medical Education and Research in Substance Abuse (AMERSA), on behalf of our organization, would like to express our appreciation of the efforts of Dr. Vivek Murthy and the Surgeon General\u27s Office to publish the first surgeon general\u27s report covering substance misuse and substance use disorders
Supersymmetric QCD: Exact Results and Strong Coupling
We revisit two longstanding puzzles in supersymmetric gauge theories. The
first concerns the question of the holomorphy of the coupling, and related to
this the possible definition of an exact (NSVZ) beta function. The second
concerns instantons in pure gluodynamics, which appear to give sensible, exact
results for certain correlation functions, which nonetheless differ from those
obtained using systematic weak coupling expansions. For the first question, we
extend an earlier proposal of Arkani-Hamed and Murayama, showing that if their
regulated action is written suitably, the holomorphy of the couplings is
manifest, and it is easy to determine the renormalization scheme for which the
NSVZ formula holds. This scheme, however, is seen to be one of an infinite
class of schemes, each leading to an exact beta function; the NSVZ scheme,
while simple, is not selected by any compelling physical consideration. For the
second question, we explain why the instanton computation in the pure
supersymmetric gauge theory is not reliable, even at short distances. The
semiclassical expansion about the instanton is purely formal; if infrared
divergences appear, they spoil arguments based on holomorphy. We demonstrate
that infrared divergences do not occur in the perturbation expansion about the
instanton, but explain that there is no reason to think this captures all
contributions from the sector with unit topological charge. That one expects
additional contributions is illustrated by dilute gas corrections. These are
infrared divergent, and so difficult to define, but if non-zero give order one,
holomorphic, corrections to the leading result. Exploiting an earlier analysis
of Davies et al, we demonstrate that in the theory compactified on a circle of
radius beta, due to infrared effects, finite contributions indeed arise which
are not visible in the formal limit that beta goes to infinity.Comment: 28 pages, two references added, one typo correcte
On the next-to-leading-order correction to the effective action in N=2 gauge theories
I attempt to analyse the next-to-leading-order non-holomorphic contribution
to the Wilsonian low-energy effective action in the four-dimensional N=2 gauge
theories with matter, from the manifestly N=2 supersymmeric point of view, by
using the harmonic superspace. The perturbative one-loop correction is found to
be in agreement with the N=1 superfield calculations of de Wit, Grisaru and
Rocek. The previously unknown coefficient in front of this non-holomorphic
correction is calculated. A special attention is devoted to the N=2
superconformal gauge theories, whose one-loop non-holomorphic contribution is
likely to be exact, even non-perturbatively. This leading (one-loop)
non-holomorphic contribution to the LEEA of the N=2 superconformally invariant
gauge field theories is calculated, and it does not vanish, similarly to the
case of the N=4 super-Yang-Mills theory.Comment: 15 pages, LaTeX; changes in the abstract and in sect.
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