273 research outputs found
Louse-borne relapsing fever—a systematic review and analysis of the literature: part 2— mortality, Jarisch–Herxheimer reaction, impact on pregnancy
Louse-borne relapsing fever (LBRF) is a classical epidemic disease, which in the past was associated with war, famine, poverty, forced migration, and crowding under poor hygienic conditions around the world. The disease’s causative pathogen, the spirochete bacterium Borrelia recurrentis, is confined to humans and transmitted by a single vector, the human body louse Pediculus humanus corporis. Since the disease was at its peak before the days of modern medicine, many of its aspects have never been formally studied and to date remain incompletely understood. In order to shed light on some of these aspects, we have systematically reviewed the accessible literature on LBRF since the recognition of its mode of transmission in 1907, and summarized the existing data on mortality, Jarisch–Herxheimer reaction (JHR), and impact on pregnancy.
Publications were identified by using a predefined search strategy of electronic databases and a subsequent review of the reference lists of the obtained publications. All publications reporting patients with a confirmed diagnosis of LBRF published in English, French, German, and Spanish since 1907 were included. Data extraction followed a predefined protocol and included a grading system to judge the certainty of the diagnosis of reported cases.
The high mortality rates often found in literature are confined to extreme scenarios. The case fatality rate (CFR) of untreated cases is on average significantly lower than frequently assumed. In recent years, a rise in the overall CFRs is documented, for which reasons remain unknown.
Lacking standardized criteria, a clear diagnostic threshold defining antibiotic treatment-induced JHR does not exist. This explains the wide range of occurrence rates found in literature. Pre-antibiotic era data suggest the existence of a JHR-like reaction also in cases treated with arsenicals and even in untreated cases.
LBRF-related adverse outcomes are observed in 3 out of 4 pregnancies
Signatures of Electronic Nematic Phase at Isotropic-Nematic Phase Transition
The electronic nematic phase occurs when the point-group symmetry of the
lattice structure is broken, due to electron-electron interactions. We study a
model for the nematic phase on a square lattice with emphasis on the phase
transition between isotropic and nematic phases within mean field theory. We
find the transition to be first order, with dramatic changes in the Fermi
surface topology accompanying the transition. Furthermore, we study the
conductivity tensor and Hall constant as probes of the nematic phase and its
transition. The relevance of our findings to Hall resistivity experiments in
the high- cuprates is discussed.Comment: 5 pages, 3 figure
Quasi-1D dynamics and nematic phases in the 2D Emery model
We consider the Emery model of a
Cu-O plane of the high temperature superconductors. We show that in a
strong-coupling limit, with strong Coulomb repulsions between electrons on
nearest-neighbor O sites, the electron-dynamics is strictly one dimensional,
and consequently a number of asymptotically exact results can be obtained
concerning the electronic structure. In particular, we show that a nematic
phase, which spontaneously breaks the point- group symmetry of the square
lattice, is stable at low enough temperatures and strong enough coupling.Comment: 8 pages, 5 eps figures; revised manuscript with more detailed
discussions; two new figures and three edited figuresedited figures; 14
references; new appendix with a detailed proof of the one-dimensional
dynamics of the system in the strong coupling limi
Intestinal perforation due to adult tapeworm of Taenia: a case report and review of the literature
Taeniasis is an intestinal helminth infection due to adult tapeworms belonging to the genus Taenia. Taeniasis remains a major burden in low-income countries in Asia. We present a case of intestinal perforation caused by adult tapeworm of Taenia in a 50-year-old Nepali male. The patients presented to the hospital with severe abdominal pain and intermittent vomiting. Following clinical presentations and imaging features, gastrointestinal perforation was suspected. Surgical removal of adult tapeworm of Taenia, suspected to be T. saginata or T. asiatica, was carried out during exploratory laparotomy, which was followed by an uneventful postoperative period. In addition to case presentation, we systematically review published case reports on taeniasis-related intestinal perforation. A learning point from this case is clinician should maintain a clinical suspicion of taeniasis as a possible cause of intestinal perforation in endemic areas
Fermi surface instabilities at finite Temperature
We present a new method to detect Fermi surface instabilities for interacting
systems at finite temperature. We first apply it to a list of cases studied
previously, recovering already known results in a very economic way, and
obtaining most of the information on the phase diagram analytically. As an
example, in the continuum limit we obtain the critical temperature as an
implicit function of the magnetic field and the chemical potential
. By applying the method to a model proposed to describe reentrant
behavior in , we reproduce the phase diagram obtained
experimentally and show the presence of a non-Fermi Liquid region at
temperatures above the nematic phase.Comment: 10 pages, 10 figure
Renormalized perturbation theory for Fermi systems: Fermi surface deformation and superconductivity in the two-dimensional Hubbard model
Divergencies appearing in perturbation expansions of interacting many-body
systems can often be removed by expanding around a suitably chosen renormalized
(instead of the non-interacting) Hamiltonian. We describe such a renormalized
perturbation expansion for interacting Fermi systems, which treats Fermi
surface shifts and superconductivity with an arbitrary gap function via
additive counterterms. The expansion is formulated explicitly for the Hubbard
model to second order in the interaction. Numerical soutions of the
self-consistency condition determining the Fermi surface and the gap function
are calculated for the two-dimensional case. For the repulsive Hubbard model
close to half-filling we find a superconducting state with d-wave symmetry, as
expected. For Fermi levels close to the van Hove singularity a Pomeranchuk
instability leads to Fermi surfaces with broken square lattice symmetry, whose
topology can be closed or open. For the attractive Hubbard model the second
order calculation yeilds s-wave superconductivity with a weakly momentum
dependent gap, whose size is reduced compared to the mean-field result.Comment: 18 pages incl. 6 figure
Van Hove singularity and spontaneous Fermi surface symmetry breaking in Sr3Ru2O7
The most salient features observed around a metamagnetic transition in
Sr3Ru2O7 are well captured in a simple model for spontaneous Fermi surface
symmetry breaking under a magnetic field, without invoking a putative quantum
critical point. The Fermi surface symmetry breaking happens in both a majority
and a minority spin band but with a different magnitude of the order parameter,
when either band is tuned close to van Hove filling by the magnetic field. The
transition is second order for high temperature T and changes into first order
for low T. The first order transition is accompanied by a metamagnetic
transition. The uniform magnetic susceptibility and the specific heat
coefficient show strong T dependence, especially a log T divergence at van Hove
filling. The Fermi surface instability then cuts off such non-Fermi liquid
behavior and gives rise to a cusp in the susceptibility and a specific heat
jump at the transition temperature.Comment: 11 pages, 4 figure
Direct mass measurements beyond the proton drip-line
First on-line mass measurements were performed at the SHIPTRAP Penning trap
mass spectrometer. The masses of 18 neutron-deficient isotopes in the
terbium-to-thulium region produced in fusion-evaporation reactions were
determined with relative uncertainties of about , nine of them
for the first time. Four nuclides (Ho and Tm) were
found to be proton-unbound. The implication of the results on the location of
the proton drip-line is discussed by analyzing the one-proton separation
energies
Spontaneous breaking of four-fold rotational symmetry in two-dimensional electronic systems explained as a continuous topological transition
The Fermi liquid approach is applied to the problem of spontaneous violation
of the four-fold rotational point-group symmetry () in strongly correlated
two-dimensional electronic systems on a square lattice. The symmetry breaking
is traced to the existence of a topological phase transition. This continuous
transition is triggered when the Fermi line, driven by the quasiparticle
interactions, reaches the van Hove saddle points, where the group velocity
vanishes and the density of states becomes singular. An unconventional Fermi
liquid emerges beyond the implicated quantum critical point.Comment: 6 pages, 4 figure
Cardiovascular diseases risk factors among recently arrived Eritrean refugees in Switzerland
For the past 10 years, refugees from Eritrea represented the majority of asylum seekers in Switzerland. However, data on their health status remains limited. In this cross-sectional survey followed by a 1-year cohort study, we screened newly arrived Eritrean refugees for cardiovascular risk factors at arrival and 1-year post registration.; Among 107 participants (88.8% male; median age 25, 9 (9%) had a body mass index ≥ 25 kg/m; 2; , one (1%) had elevated blood pressure, one (1%) had diabetes, 19% smoked and two (2%) had a low density lipoprotein (LDL) cholesterol ≥ 4.1 mmol/l. Among the 48 participants (5 females, 43 males) followed, there were no significant changes in cardiovascular risk profile 1 year post-arrival
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