3,262 research outputs found
Two-axis controller Patent
Two axis flight controller with potentiometer control shafts directly coupled to rotatable ball member
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Predictors of Missed Hepatitis C Intake Appointments and Failure to Establish Hepatitis C Care Among Patients Living With HIV.
BackgroundWe estimated and characterized the proportion of patients living with HIV (PLWH) who missed hepatitis C (HCV) intake appointments and subsequently failed to establish HCV care.MethodsLogistic regression analyses were used to identify factors associated with missed HCV intake appointments and failure to establish HCV care among PLWH referred for HCV treatment between January 2014 and December 2017. In addition to demographics, variables included HIV treatment characteristics, type of insurance, liver health status, active alcohol or illicit drug use, unstable housing, and history of a mental health disorder (MHD).ResultsDuring the study period, 349 new HCV clinic appointments were scheduled for 202 unduplicated patients. Approximately half were nonwhite, and 80% had an undetectable HIV viral load. Drug use (31.7%), heavy alcohol use (32.8%), and MHD (37.8%) were prevalent. Over the 4-year period, 21.9% of PLWH referred for HCV treatment missed their HCV intake appointment. The proportion increased each year, from 17.2% in 2014 to 25.4% in 2017 (P = .021). Sixty-six of the 202 newly referred HCV patients (32.7%) missed their first HCV appointment, and 28 of these (42.4%) failed to establish HCV care. Having a history of MHD, CD4 <200, ongoing drug use, and being nonwhite were independent predictors of missing an intake HCV appointment. The strongest predictor of failure to establish HCV care was having a detectable HIV viral load.ConclusionsThe proportion of PLWH with missed HCV appointments increased over time. HCV elimination among PLWH may require integrated treatment of MHD and substance use
Analytical Study of Diffusive Relativistic Shock Acceleration
Particle acceleration in relativistic shocks is studied analytically in the
test-particle, small-angle scattering limit, for an arbitrary velocity-angle
diffusion function D. Accurate analytic expressions for the spectral index s
are derived using few (2-6) low-order moments of the shock-frame angular
distribution. For isotropic diffusion, previous results are reproduced and
justified. For anisotropic diffusion, s is shown to be sensitive to D,
particularly downstream and at certain angles, and a wide range of s values is
attainable. The analysis, confirmed numerically, can be used to test
collisionless shock models and to observationally constrain D. For example,
strongly forward- or backward-enhanced diffusion downstream is ruled out by GRB
afterglow observations.Comment: 4 pages, 2 figures, PRL accepted, minor change
Target value design: using collaboration and a lean approach to reduce construction cost
Target Costing is an effective management technique that has been used in manufacturing for decades to achieve cost predictability during new products development. Adoption of this technique promises benefits for the construction industry as it struggles to raise the number of successful outcomes and certainty of project delivery in terms of cost, quality and time. Target Value Design is a management approach that takes the best features of Target Costing and adapts them to the peculiarities of construction. In this paper the concept of Target Value Design is introduced based on the results of action research carried out on 12 construction projects in the USA. It has been shown that systemic application of Target Value Design leads to significant improvement of project performance – the final cost of projects was on average 15% less than market cost. The construction industry already has approaches that have similarities with elements of the Target Value Design process or uses the same terminology, e.g. Partnering and Target Cost Contracts, Cost planning, etc. Following an exploration of the similarities and differences Target Value Design is positioned as a form of Target Costing for construction that offers a more reliable route to successful projects outcomes
Self-Similar Collisionless Shocks
Observations of gamma-ray burst afterglows suggest that the correlation
length of magnetic field fluctuations downstream of relativistic non-magnetized
collisionless shocks grows with distance from the shock to scales much larger
than the plasma skin depth. We argue that this indicates that the plasma
properties are described by a self-similar solution, and derive constraints on
the scaling properties of the solution. For example, we find that the scaling
of the characteristic magnetic field amplitude with distance from the shock is
B \propto D^{s_B} with -1<s_B<=0, that the spectrum of accelerated particles is
dn/dE \propto E^{-2/(s_B+1)}, and that the scaling of the magnetic correlation
function is \propto x^{2s_B} (for x>>D). We show that the
plasma may be approximated as a combination of two self-similar components: a
kinetic component of energetic particles and an MHD-like component representing
"thermal" particles. We argue that the latter may be considered as infinitely
conducting, in which case s_B=0 and the scalings are completely determined
(e.g. dn/dE \propto E^{-2} and B \propto D^0). Similar claims apply to non-
relativistic shocks such as in supernova remnants, if the upstream magnetic
field can be neglected. Self-similarity has important implications for any
model of particle acceleration and/or field generation. For example, we show
that the diffusion function in the angle \mu of momentum p in diffusive shock
acceleration models must satisfy D_{\mu\mu}(p,D) = D^{-1}D'_{\mu\mu}(p/D), and
that a previously suggested model for the generation of large scale magnetic
fields through a hierarchical merger of current-filaments should be
generalized. A numerical experiment testing our analysis is outlined
(Abridged).Comment: 16 pages, 1 figure, accepted for publication in Ap
Particle acceleration at ultrarelativistic shocks: an eigenfunction method
We extend the eigenfunction method of computing the power-law spectrum of
particles accelerated at a relativistic shock fronts to apply to shocks of
arbitrarily high Lorentz factor. In agreement with the findings of Monte-Carlo
simulations, we find the index of the power-law distribution of accelerated
particles which undergo isotropic diffusion in angle at an ultrarelativistic,
unmagnetized shock is s=4.23 (where s=-d(ln f)/dp with f the Lorentz invariant
phase-space density and p the momentum). This corresponds to a synchrotron
index for uncooled electrons of a=0.62 (taking cooling into account a=1.12),
where a=-d(ln F)/dn, F is the radiation flux and n the frequency. We also
present an approximate analytic expression for the angular distribution of
accelerated particles, which displays the effect of particle trapping by the
shock: compared with the non-relativistic case the angular distribution is
weighted more towards the plane of the shock and away from its normal. We
investigate the sensitivity of our results to the transport properties of the
particles and the presence of a magnetic field. Shocks in which the ratio of
Poynting to kinetic energy flux upstream is not small are less compressive and
lead to larger values of .Comment: Minor additions on publicatio
Inhaled nitric oxide in premature infants: effect on tracheal aspirate and plasma nitric oxide metabolites
ObjectiveInhaled nitric oxide (iNO) is a potential new therapy for prevention of bronchopulmonary dysplasia and brain injury in premature infants. This study examined dose-related effects of iNO on NO metabolites as evidence of NO delivery.Study designA subset of 102 premature infants in the NO CLD trial, receiving 24 days of iNO (20 p.p.m. decreasing to 2 p.p.m.) or placebo, were analyzed. Tracheal aspirate (TA) and plasma samples collected at enrollment and at intervals during study gas were analyzed for NO metabolites.ResultiNO treatment increased NO metabolites in TA at 20 and 10 p.p.m. (1.7- to 2.3-fold vs control) and in plasma at 20, 10, and 5 p.p.m. (1.6- to 2.3-fold). In post hoc analysis, treated infants with lower metabolite levels at entry had an improved clinical outcome.ConclusioniNO causes dose-related increases in NO metabolites in the circulation as well as lung fluid, as evidenced by TA analysis, showing NO delivery to these compartments
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