Sexually Transmitted Infections and Sexual Behaviour Among Commercial Sex Workers in a Rural District of Malawi.

In Thyolo District, Malawi, a study was conducted among commercial sex workers (CSWs) attending mobile clinics in order to; determine the prevalence and pattern of sexually transmitted infections (STIs), describe sexual behaviour among those who have an STI and identify risk factors associated with 'no condom use'. There were 1817 CSWs, of whom 448 (25%) had an STI. Of these, the commonest infections included 237 (53%) cases of abnormal vaginal discharge, 109 (24%) cases of pelvic inflammatory disease and 95 (21%) cases of genital ulcer disease (GUD). Eighty-seven per cent had sex while symptomatic, 17% without condoms. Having unprotected sex was associated with being married, being involved with commercial sex outside a known rest-house or bar, having a GUD, having fewer than two clients/day, alcohol intake and having had no prior medication for STI. The high levels of STIs, particularly GUDs, and unprotected sex underlines the importance of developing targeted interventions for CSWs and their clients

Inferring spatial variations in velocity profiles and bed geometry of natural debris flows based on discharge estimates from high-frequency 3D LiDAR point clouds; Illgraben, Switzerland

More detailed field measurements are required for a better understanding of surging debris flows. In this work, we analyze a debris flow at the field-scale using timelapse point clouds from a high-resolution, high-frequency 3D LiDAR sensor, which has been installed over a check dam on the fan of the Illgraben catchment in Switzerland. In our investigations, we manually measured the front velocity and tracked individual features such as large boulders and woody debris over a 25 m long channel segment. We observed a change in the front velocity as well as a difference in the velocity of large boulders and woody debris (vboulder ≈ 0.6 vwood) during the second surge of the event. We also estimated the discharge for different closely spaced channel sections based on automated measurements of the cross-sectional area and the surface velocity, which enabled us to infer spatial variations in the bed geometry and the velocity profile. From the discharge estimates, we then derived the volume of this event. Over the course of the next year, the amount of field-scale LiDAR data from the Illgraben will increase substantially and allow for an even more detailed analysis of fundamental debris-flow processes

Quantum Noise and Superluminal Propagation

Causal "superluminal" effects have recently been observed and discussed in various contexts. The question arises whether such effects could be observed with extremely weak pulses, and what would prevent the observation of an "optical tachyon." Aharonov, Reznik, and Stern (ARS) [Phys. Rev. Lett., vol. 81, 2190 (1998)] have argued that quantum noise will preclude the observation of a superluminal group velocity when the pulse consists of one or a few photons. In this paper we reconsider this question both in a general framework and in the specific example, suggested by Chiao, Kozhekin, and Kurizki [Phys. Rev. Lett., vol. 77, 1254 (1996)], of off-resonant, short-pulse propagation in an optical amplifier. We derive in the case of the amplifier a signal-to-noise ratio that is consistent with the general ARS conclusions when we impose their criteria for distinguishing between superluminal propagation and propagation at the speed c. However, results consistent with the semiclassical arguments of CKK are obtained if weaker criteria are imposed, in which case the signal can exceed the noise without being "exponentially large." We show that the quantum fluctuations of the field considered by ARS are closely related to superfluorescence noise. More generally we consider the implications of unitarity for superluminal propagation and quantum noise and study, in addition to the complete and truncated wavepackets considered by ARS, the residual wavepacket formed by their difference. This leads to the conclusion that the noise is mostly luminal and delayed with respect to the superluminal signal. In the limit of a very weak incident signal pulse, the superluminal signal will be dominated by the noise part, and the signal-to-noise ratio will therefore be very small.Comment: 30 pages, 1 figure, eps

Debris-flow monitoring with high-frequency LiDAR scanners: A new method to infer the internal dynamics of debris flows

In-situ measurements of debris-flow properties are crucial for understanding their movement mechanisms and quantifying their impact. Here we present the first results of a field monitoring campaign, at Illgraben, Switzerland, to measure debris-flow parameters using high temporal (10 Hz) and spatial resolution LiDAR sensors at several locations along the channel. The point cloud data is projected onto video images to enhance visualization and aid in the interpretation of the measurements. We process the data using machine vision and deep learning based algorithms, and show that this system can accurately measure front and flow surface velocity, flow depth and bed elevation change, as well as the size, style of motion (e.g. rotating or floating without rotation) and trajectories of individual particles. This system thus provides a promising new method for inferring the internal dynamics of debris flows

Resonant tunneling of electromagnetic waves through polariton gaps

We consider resonant tunneling of electromagnetic waves through an optical barrier formed by dielectric layers with the frequency dispersion of their dielectric permiability. The frequency region between lower and upper polariton branches in these materials presents a stop band for electromagnetic waves. We show that resonance tunneling through this kind of barriers is qualitatevely different from tunneling through other kind of optical barriers as well as from quantum mechanic tunneling through a rectangular barrier. We find that the width of the resonance maxima of the transmission coeffcient tends to zero as frequency approach the lower boundary of the stop band in a very sharp non-analytical way. Resonance transmission peaks give rise to new photonic bands inside the stop band if one considers periodical array of the layers.Comment: 8 pages, 5 figure

CMV-specific T-cells Mobilized with Exercise have Broad Epitope Specificity and a High-Differentiated Effector Memory Phenotype.

Introduction: Dynamic exercise evokes a rapid redeployment of cytotoxic T-cell subsets with high surface expression of b2 adrenergic receptors, presumably to enhance immunosurveillance during acute stress. As this response is affected by age and infection history, the main aim of this study was to examine latent CMV infection as a potential confounder to age-related differences in blood CD8+ T-cell responses to exercise. The second aim of this study was to examine the impact of acute exercise on the mobilization of CMV-specific T-cells in the peripheral blood compartment. Methods: Healthy young (n=16) and older (n=16) humans counterbalanced by CMV IgG serostatus (positive or negative) exercised for 30-minutes at ~80% peak cycling power. Isolated blood lymphocytes phenotypes were assessed by flow cytometry and Enzyme-linked immunospot (ELISPOT) analysis was used to determine the frequency and function of T-cells secreting IFN-g in response to CMV antigens. Maximum likelihood linear mixed models (LMM) were used to determine main effects of exercise (pre, post and 1h post-exercise), age (young or old) and CMV status (positive or negative) on total numbers of blood lymphocytes and their subsets. Results: Those with CMV redeployed ~2 times more CD8+ T-cells and ~6-times more KLRG1+/CD28- and CD45RA+/CCR7- CD8+ subsets than non-infected exercisers. Seronegative older exercisers had an impaired redeployment of total CD8+ T-cells, CD45RA+/CCR7+ and (KLRG1-/CD28+) CD8+ subsets. Redeployed CD8+ T-cell numbers were similar between infected young and old. CMVpp65 specific CD8+ cells in HLA/A2* subjects increased ~2.7 fold after exercise, a response that was driven by the KLRG1+/CD28-/CD8+ subset. Stimulating PBMCs before and after exercise with CMVpp65 and CMV IE-1 antigens and overlapping peptide pools revealed a 2.1 and 4.4 fold increases in CMVpp65 and CMV IE-1 IFN-g secreting cells respectively. The breadth of the T cell response was maintained after exercise with the magnitude of the response being amplified across the entire epitope repertoire. Conclusion: We conclude that latent CMV infection overrides age-related impairments in CD8+ T-cell redeployment with exercise. We also show for the first time that many T-cells redeployed with exercise are specific to CMVpp65 and CMV IE-1 antigens, have broad epitope specificity, and are mostly of a high-differentiated effector memory phenotype. We anticipate that these findings may have clinical implications, with acute exercise serving as a simple strategy to increase numbers of available antigen-specific cells in blood that can be harvested for expansion and adoptive T-cell transfer in HSCT recipients

On a universal photonic tunnelling time

We consider photonic tunnelling through evanescent regions and obtain general analytic expressions for the transit (phase) time $\tau$ (in the opaque barrier limit) in order to study the recently proposed ``universality'' property according to which $\tau$ is given by the reciprocal of the photon frequency. We consider different physical phenomena (corresponding to performed experiments) and show that such a property is only an approximation. In particular we find that the ``correction'' factor is a constant term for total internal reflection and quarter-wave photonic bandgap, while it is frequency-dependent in the case of undersized waveguide and distributed Bragg reflector. The comparison of our predictions with the experimental results shows quite a good agreement with observations and reveals the range of applicability of the approximated ``universality'' property.Comment: RevTeX, 8 pages, 4 figures, 1 table; subsection added with a new experiment analyzed, some other minor change

Preventing Farnesylation of the Dynein Adaptor Spindly Contributes to the Mitotic Defects Caused by Farnesyltransferase Inhibitors

The clinical interest in farnesyltransferase inhibitors (FTIs) makes it important to understand how these compounds affect cellular processes involving farnesylated proteins. Mitotic abnormalities observed after treatment with FTIs have so far been attributed to defects in the farnesylation of the outer kinetochore proteins CENP-E and CENP-F, which are involved in chromosome congression and spindle assembly checkpoint signaling. Here we identify the cytoplasmic dynein adaptor Spindly as an additional component of the outer kinetochore that is modified by farnesyltransferase (FTase). We show that farnesylation of Spindly is essential for its localization, and thus for the proper localization of dynein and its cofactor dynactin, to prometaphase kinetochores and that Spindly kinetochore recruitment is more severely affected by FTase inhibition than kinetochore recruitment of CENP-E and CENP-F. Molecular replacement experiments show that both Spindly and CENP-E farnesylation are required for efficient chromosome congression. The identification of Spindly as a new mitotic substrate of FTase provides insight into the causes of the mitotic phenotypes observed with FTase inhibitors

Helmholtz theorem and the v-gauge in the problem of superluminal and instantaneous signals in classical electrodynamics

In this work we substantiate the applying of the Helmholtz vector decomposition theorem (H-theorem) to vector fields in classical electrodynamics. Using the H-theorem, within the framework of the two-parameter Lorentz-like gauge (so called v-gauge), we show that two kinds of magnetic vector potentials exist: one of them (solenoidal) can act exclusively with the velocity of light c and the other one (irrotational) with an arbitrary finite velocity $v$ (including a velocity more than c . We show also that the irrotational component of the electric field has a physical meaning and can propagate exclusively instantaneously.Comment: This variant has been accepted for publication in Found. Phys. Letter

13th Meeting of the Scientific Group on Methodologies for the Safety Evaluation of Chemicals (SGOMSEC): alternative testing methodologies for organ toxicity.

In the past decade in vitro tests have been developed that represent a range of anatomic structure from perfused whole organs to subcellular fractions. To assess the use of in vitro tests for toxicity testing, we describe and evaluate the current status of organotypic cultures for the major target organs of toxic agents. This includes liver, kidney, neural tissue, the hematopoietic system, the immune system, reproductive organs, and the endocrine system. The second part of this report reviews the application of in vitro culture systems to organ specific toxicity and evaluates the application of these systems both in industry for safety assessment and in government for regulatory purposes. Members of the working group (WG) felt that access to high-quality human material is essential for better use of in vitro organ and tissue cultures in the risk assessment process. Therefore, research should focus on improving culture techniques that will allow better preservation of human material. The WG felt that it is also important to develop and make available relevant reference compounds for toxicity assessment in each organ system, to organize and make available via the Internet complete in vivo toxicity data, including human data, containing dose, end points, and toxicokinetics. The WG also recommended that research should be supported to identify and to validate biological end points for target organ toxicity to be used in alternative toxicity testing strategies