2,578 research outputs found
Teaching the patient with myocardial infarction
Thesis (M.S.)--Boston Universit
A Constraint Programming Approach to the Hospitals / Residents Problem
An instance I of the Hospitals / Residents problem (HR) involves a set of residents
(graduating medical students) and a set of hospitals, where each hospital has a given
capacity. The residents have preferences for the hospitals, as do hospitals for residents.
A solution of I is a stable matching, which is an assignment of residents to hospitals
that respects the capacity conditions and preference lists in a precise way. In this
paper we present constraint encodings for HR that give rise to important structural
properties. We also present a computational study using both randomly-generated
and real-world instances. Our study suggests that Constraint Programming is indeed
an applicable technology for solving this problem, in terms of both theory and practice
A meta analysis of effectiveness of E interventions to reduce alcohol consumption in college and university students
Objective: To evaluate the effectiveness and moderators of E-Interventions versus assessment only (AO) controls in the reduction of alcoholic drinks per week (DPW) in university students.
Study design and methods: Cochrane library, CINAEL, ERIC, MEDLINE, PsycINFO, PubMed, and Web of Science were searched up to June 2017. Studies were included if they were: an RCT, assessed the effectiveness of E-Interventions at reducing DPW, and employed university/college students. 23 studies (N = 7,614) were included and quality was assessed using the JADAD scale.
Results: Weighted mean effect sizes were calculated using random-effects models. These showed a small, significant effect of E-Interventions at reducing the number of alcoholic DPW. Moderator analysis found a significant advantage for web-based personalised feedback interventions compared to other E-Interventions.
Conclusions: E-Interventions show a small, significant effect at reducing mean alcoholic DPW. Personalised feedback E-Interventions showed the strongest effect
Photometry and spectroscopy in the open cluster Alpha Persei, 2
Results from a combination of new spectroscopic and photometric observations in the lower main-sequence and pre-main sequence of the open cluster alpha Persei are presented. New echelle spectroscopy has provided radial and rotational velocity information for thirteen candidate members, three of which are nonmembers based on radial velocity, absence of a Li 6707A feature, and absence of H-alpha emission. A set of revised rotational velocity estimates for several slowly rotating candidates identified earlier is given, yielding rotational velocities as low as 7 km/s for two apparent cluster members. VRI photometry for several pre-main sequence members is given; the new (V,V-I(sub K)) photometry yields a more clearly defined pre-main sequence. A list of approximately 43 new faint candidate members based on the (V,V-I(sub K)) CCD photometry is presented in an effort to identify additional cluster members at very low masses. Low-dispersion spectra obtained for several of these candidates provide in some cases supporting evidence for cluster membership. The single brown dwarf candidate in this cluster is for the first time placed in a color-magnitude diagram with other cluster members, providing a better means for establishing its true status. Stars from among the list of new photometric candidates may provide the means for establishing a sequence of cluster members down to very faint magnitudes (V approximately 21) and consequently very low masses. New coordinate determinations for previous candidate members and finding charts for the new photometric candidates are provided in appendices
A Visit to West Point
"The name of West Point is dear to the heart of every patriotic American citizen…
Generalized Arago-Fresnel laws: The EME-flow-line description
We study experimentally and theoretically the influence of light polarization
on the interference patterns behind a diffracting grating. Different states of
polarization and configurations are been considered. The experiments are
analyzed in terms of electromagnetic energy (EME) flow lines, which can be
eventually identified with the paths followed by photons. This gives rise to a
novel trajectory interpretation of the Arago-Fresnel laws for polarized light,
which we compare with interpretations based on the concept of "which-way" (or
"which-slit") information.Comment: 14 pages, 6 figure
Rotation periods of late-type stars in the young open cluster IC 2602
We present the results of a monitoring campaign aimed at deriving rotation
periods for a representative sample of stars in the young (30 Myr) open cluster
IC 2602. Rotation periods were derived for 29 of 33 stars monitored. The
periods derived range from 0.2d (one of the shortest known rotation periods of
any single open cluster star) to about 10d (which is almost twice as long as
the longest period previously known for a cluster of this age). We are able to
confirm 8 previously known periods and derive 21 new ones, delineating the long
period end of the distribution. Despite our sensitivity to longer periods, we
do not detect any variables with periods longer than about 10d. The combination
of these data with those for IC 2391, an almost identical cluster, leads to the
following conclusions:
1) The fast rotators in a 30 Myr cluster are distributed across the entire
0.5 < B-V < 1.6 color range.
2) 6 stars in our sample are slow rotators, with periods longer than 6d.
3) The amplitude of variability depends on both the color and the period. The
dependence on the latter might be important in understanding the selection
effects in the currently available rotation period database and in planning
future observations.
4) The interpretation of these data in terms of theoretical models of
rotating stars suggests both that disk-interaction is the norm rather than the
exception in young stars and that disk-locking times range from zero to a few
Myr.Comment: 23 pages, 8 figures, accepted for publication in the Astrophysical
Journa
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