7,302 research outputs found
Errors on the inverse problem solution for a noisy spherical gravitational wave antenna
A single spherical antenna is capable of measuring the direction and
polarization of a gravitational wave. It is possible to solve the inverse
problem using only linear algebra even in the presence of noise. The simplicity
of this solution enables one to explore the error on the solution using
standard techniques. In this paper we derive the error on the direction and
polarization measurements of a gravitational wave. We show that the solid angle
error and the uncertainty on the wave amplitude are direction independent. We
also discuss the possibility of determining the polarization amplitudes with
isotropic sensitivity for any given gravitational wave source.Comment: 13 pages, 4 figures, LaTeX2e, IOP style, submitted to CQ
Results on a pedagogic approach for tailoring public health interventions to minimise opportunistic infections.
We are performing curriculum modifications on the first year BSc (Hons) Biomedical Science module “Basic Microbiology” (De Montfort University, UK) to increase students’ knowledge of basic medical parasitology and infectious diseases, so these students can acquire the necessary skills to tackle their final degree module “Medical Microbiology”. Following student feedback on a novel short intervention in 2017/18 to promote awareness about human immunodeficiency virus (HIV), we have created an engaging workshop session to cover not only HIV but also the opportunistic infections that can affect HIV patients that have developed acquired immune deficiency syndrome (AIDS) and how to prevent them. The objective of this work was to evaluate the effectiveness of the improved workshop developed and to collect students’ impressions to perform further modifications if needed. Briefly, students were required to develop public health measures for HIV positive patients with two different degrees of immunosuppression (i.e. with CD4+ T cells in peripheral blood above and below 200 cells/μl) to prevent exposure and infection from opportunistic pathogens such as Cryptosporidium spp., Toxoplasma gondii or Pneumocystis jirovecii from: a) sexual exposures; b) intravenous drug use; b) environment and work; c) food and water; d) foreign travel. Students, following evidence-based public health methodology, tailored their measures or interventions using the most up-to-date information reported in the literature regarding HIV chemoprophylaxis and recent guidelines published by US Department of Health and Human Services on HIV/AIDS treatment and prevention. Interventions were critically analysed with all students in the last 20 min. of the workshop, which was repeated several times due to the number of students (n=203). The objectives of this workshop were evaluated by careful analysis of a specific feedback questionnaire (n=46 out of 203) voluntarily completed by students at the end of the workshop. The questionnaire showed the following feedback: 80.4% (65.2% agreed; 15.2% strongly agreed) indicated that they learnt how to identify public health interventions; and 95.7% (56.5% agreed; 39.1% strongly agreed) indicated that they would be able to establish measures to reduce HIV transmission and prevent opportunistic infections. Additionally, 95.7% (39.1% agreed; 56.5% strongly agreed) indicated that the workshop helped them to understand the relevance of local and global interventions. Finally, 97.8% of responders considered that the content (52.2% agreed; 45.7% strongly agreed) and duration (60.9% agreed; 37% strongly agreed) of the workshop was appropriate; and 89.1% (58.7% agreed; 30.4% strongly agreed) and 73.9% (41.3% agreed; 32.6% strongly agreed) enjoyed and were satisfied with the workshop provided, respectively. In conclusion, the improved workshop developed would seem to be effective for promoting sexual and public health education to minimise opportunistic pathogen infections in relevant patients when delivered to students with a basic knowledge of microbiology and parasitology
An Adult with Episodic Abnormal Limb Posturing
info:eu-repo/semantics/publishedVersio
Specific heat of a non-local attractive Hubbard model
The specific heat of an attractive (interaction ) non-local Hubbard
model is investigated. We use a two-pole approximation which leads to a set of
correlation functions. In particular, the correlation function $\
G\delta\delta=1-n_Tn_T=n_{\uparrow}+n_{\downarrow}(0,\pm\pi)(\pm\pi,0)$ eliminates the two peak structure, the low
temperature peak remaining. The effects of the second nearest neighbor hopping
on the specific heat are also investigated.Comment: 5 pages, 7 figure
Boltzmann equation simulation for a trapped Fermi gas of atoms
The dynamics of an interacting Fermi gas of atoms at sufficiently high
temperatures can be efficiently studied via a numerical simulation of the
Boltzmann equation. In this work we describe in detail the setup we used
recently to study the oscillations of two spin-polarised fermionic clouds in a
trap. We focus here on the evaluation of interparticle interactions. We compare
different ways of choosing the phase space coordinates of a pair of atoms after
a successful collision and demonstrate that the exact microscopic setup has no
influence on the macroscopic outcome
Stable Gravastars of Anisotropic Dark Energy
Dynamical models of prototype gravastars made of phantom energy are
constructed, in which an infinitely thin spherical shell of a perfect fluid
with the equation of state divides the whole spacetime
into two regions, the internal region filled with a dark energy (or phantom)
fluid, and the external Schwarzschild region. It is found that in some cases
the models represent the "bounded excursion" stable gravastars, where the thin
shell is oscillating between two finite radii, while in other cases they
collapse until the formation of black holes or normal stars. In the phase
space, the region for the "bounded excursion" gravastars is very small in
comparison to that of black holes, but not empty, as found in our previous
papers. Therefore, although the existence of gravastars can not be completely
excluded from current analysis, the opposite is not possible either, that is,
even if gravastars exist, they do not exclude the existence of black holes.Comment: 35 pages, 43 figures, added some clarifying texts and corrected some
typos, accepted for publication in JCA
Infrared Signature of the Superconducting State in Pr(2-x)Ce(x)CuO(4)
We measured the far infrared reflectivity of two superconducting
Pr(2-x)Ce(x)CuO(4) films above and below Tc. The reflectivity in the
superconducting state increases and the optical conductivity drops at low
energies, in agreement with the opening of a (possibly) anisotropic
superconducting gap. The maximum energy of the gap scales roughly with Tc as 2
Delta_{max} / kB Tc ~ 4.7. We determined absolute values of the penetration
depth at 5 K as lambda_{ab} = (3300 +/- 700) A for x = 0.15 and lambda_{ab} =
(2000 +/- 300) A for x = 0.17. A spectral weight analysis shows that the
Ferrell-Glover-Tinkham sum rule is satisfied at conventional low energy scales
\~ 4 Delta_{max}.Comment: 4 pages, 4 figure
Optical conductivity of URuSi in the Kondo Liquid and Hidden-Order Phases
We measured the polarized optical conductivity of URuSi from room
temperature down to 5 K, covering the Kondo state, the coherent Kondo liquid
regime, and the hidden-order phase. The normal state is characterized by an
anisotropic behavior between the ab plane and c axis responses. The ab plane
optical conductivity is strongly influenced by the formation of the coherent
Kondo liquid: a sharp Drude peak develops and a hybridization gap at 12 meV
leads to a spectral weight transfer to mid-infrared energies. The c axis
conductivity has a different behavior: the Drude peak already exists at 300 K
and no particular anomaly or gap signature appears in the coherent Kondo liquid
regime. When entering the hidden-order state, both polarizations see a dramatic
decrease in the Drude spectral weight and scattering rate, compatible with a
loss of about 50 % of the carriers at the Fermi level. At the same time a
density-wave like gap appears along both polarizations at about 6.5 meV at 5 K.
This gap closes respecting a mean field thermal evolution in the ab plane.
Along the c axis it remains roughly constant and it "fills up" rather than
closing.Comment: 10 pages, 7 figure
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