5,573 research outputs found
Matching small functions using centroid jitter and two beam position monitors
Matching to small beta functions is required to preserve emittance in plasma
accelerators. The plasma wake provides strong focusing fields, which typically
require beta functions on the mm-scale, comparable to those found in the final
focusing of a linear collider. Such beams can be time consuming to
experimentally produce and diagnose. We present a simple, fast, and noninvasive
method to measure Twiss parameters in a linac using two beam position monitors
only, relying on the similarity of the beam phase space and the jitter phase
space. By benchmarking against conventional quadrupole scans, the viability of
this technique was experimentally demonstrated at the FLASHForward
plasma-accelerator facility.Comment: 8 pages, 7 figure
Cervical cancer prevention in transgender men : a review
Funding MA was supported by the Horizon 2020 Framework Programme for Research and Innovation of the European Commission, through the RISCC Network (grant no.847845)Peer reviewedPostprin
Is antenatal group B streptococcal carriage a predictor of adverse obstetric outcome?
OBJECTIVES: While early-onset neonatal GBS sepsis is positively associated with premature birth and prolonged rupture of membranes, there is debate in the literature as to whether maternal GBS colonization is a predictor of adverse obstetric outcome. This is a critical issue to resolve for appropriate management (expectant vs. interventional management) of the patient presenting with premature rupture of membranes, who has no overt signs of sepsis, but who is colonized with GBS. METHODS: Since 1981 it has been hospital policy to screen all public patients antenatally for genital carriage of GBS by collection of a low vaginal swab at 28-32 weeks. All patients colonized with GBS antenatally are given penicillin as intrapartum chemoprophylaxis. Review of all GBS-colonized antenatal patients for a 12-month period (580 of 4,495 patients) and a randomized (every fourth consecutive antenatal patient) number of noncolonized patients (958) was made. Lower vaginal GBS colonization and other risk factors for preterm delivery were assessed using univariate and multivariate generalized linear modeling. RESULTS: In the study group, the maternal GBS colonization rate was 12.9%. When cofounding variables were controlled in a multivariate analysis, the association between antepartum GBS colonization and preterm labor and preterm rupture of membranes was not significant. CONCLUSION: Maternal antenatal carriage of GBS does not predict preterm labor. Therefore it is appropriate that expectant management occur for a GBS-colonized woman who ruptures her membranes, is not in labor, and has no evidence of sepsis
Ultrasonic studies of the magnetic phase transition in MnSi
Measurements of the sound velocities in a single crystal of MnSi were
performed in the temperature range 4-150 K. Elastic constants, controlling
propagation of longitudinal waves reveal significant softening at a temperature
of about 29.6 K and small discontinuities at 28.8 K, which corresponds to
the magnetic phase transition in MnSi. In contrast the shear elastic moduli do
not show any softening at all, reacting only to the small volume deformation
caused by the magneto-volume effect. The current ultrasonic study exposes an
important fact that the magnetic phase transition in MnSi, occurring at 28.8 K,
is just a minor feature of the global transformation marked by the rounded
maxima or minima of heat capacity, thermal expansion coefficient, sound
velocities and absorption, and the temperature derivative of resistivity.Comment: 4 pages, 4 figure
General massive one-loop off-shell three-point functions
In this work we compute the most general massive one-loop off-shell
three-point vertex in D-dimensions, where the masses, external momenta, and
exponents of propagators are arbitrary. This follows our previous paper in
which we have calculated several new hypergeometric series representations for
massless and massive (with equal masses) scalar one-loop three-point functions,
in the negative dimensional approach.Comment: 16 pages, 2 figures, 4 table
HPV vaccination of immunocompromised hosts.
It is well-established that immunocompromised people are at increased risk of HPV-related disease compared with those who are immunocompetent. Prophylactic HPV sub-unit vaccines are safe and immunogenic in immunocompromised people and it is strongly recommended that vaccination occur according to national guidelines. When delivered to immunocompromised populations, HPV vaccines should be given as a 3-dose regimen
Smectic ordering in liquid crystal - aerosil dispersions II. Scaling analysis
Liquid crystals offer many unique opportunities to study various phase
transitions with continuous symmetry in the presence of quenched random
disorder (QRD). The QRD arises from the presence of porous solids in the form
of a random gel network. Experimental and theoretical work support the view
that for fixed (static) inclusions, quasi-long-range smectic order is destroyed
for arbitrarily small volume fractions of the solid. However, the presence of
porous solids indicates that finite-size effects could play some role in
limiting long-range order. In an earlier work, the nematic - smectic-A
transition region of octylcyanobiphenyl (8CB) and silica aerosils was
investigated calorimetrically. A detailed x-ray study of this system is
presented in the preceding Paper I, which indicates that pseudo-critical
scaling behavior is observed. In the present paper, the role of finite-size
scaling and two-scale universality aspects of the 8CB+aerosil system are
presented and the dependence of the QRD strength on the aerosil density is
discussed.Comment: 14 pages, 10 figures, 1 table. Companion paper to "Smectic ordering
in liquid crystal - aerosil dispersions I. X-ray scattering" by R.L. Leheny,
S. Park, R.J. Birgeneau, J.-L. Gallani, C.W. Garland, and G.S. Iannacchion
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