Detectability of dissipative motion in quantum vacuum via superradiance

We propose an experiment for generating and detecting vacuum-induced dissipative motion. A high frequency mechanical resonator driven in resonance is expected to dissipate energy in quantum vacuum via photon emission. The photons are stored in a high quality electromagnetic cavity and detected through their interaction with ultracold alkali-metal atoms prepared in an inverted population of hyperfine states. Superradiant amplification of the generated photons results in a detectable radio-frequency signal temporally distinguishable from the expected background.Comment: 4 pages, 2 figure

Below-Ground Biomass in Healthy and Impaired Salt Marshes

Twelve salt marshes in south Louisiana (USA) were classified as either ‘impaired’ or ‘healthy’ before a summer sample collection of above- and below-ground biomass and determination of sediment accretion rates. The above-ground biomass of plant tissues was the same at both impaired and healthy salt marshes and was not a good predictor of marsh health. However, below-ground root biomass in the upper 30 cm was much lower in the impaired marshes compared to the healthy marshes. Compromises to root production apparently occur before there is an obvious consequence to the above-ground biomass, which may quickly collapse before remedial action can be taken. The subsequent change in vertical position of the marsh surface may be equivalent to many years of accretion, and be irreversible within decades without considerable effort. These results are consistent with the hypothesis that it is the plant’s below-ground accumulation of organic matter, not inorganic matter that governs the maintenance of salt marsh ecosystem in the vertical plane. Reversing the precursor conditions leading to marsh stress before the collapse of the above-ground biomass occurs is therefore a prudent management objective and could be easier than restoration

Two-Dimensional Hydrodynamic Simulations of Convection in Radiation-Dominated Accretion Disks

The standard equilibrium for radiation-dominated accretion disks has long been known to be viscously, thermally, and convectively unstable, but the nonlinear development of these instabilities---hence the actual state of such disks---has not yet been identified. By performing local two-dimensional hydrodynamic simulations of disks, we demonstrate that convective motions can release heat sufficiently rapidly as to substantially alter the vertical structure of the disk. If the dissipation rate within a vertical column is proportional to its mass, the disk settles into a new configuration thinner by a factor of two than the standard radiation-supported equilibrium. If, on the other hand, the vertically-integrated dissipation rate is proportional to the vertically-integrated total pressure, the disk is subject to the well-known thermal instability. Convection, however, biases the development of this instability toward collapse. The end result of such a collapse is a gas pressure-dominated equilibrium at the original column density.Comment: 10 pages, 7 figures, accepted for publication in ApJ. Please send comments to [email protected]

The lattice stiffening transition in UO2 single crystals

The effective Debye temperatures (θDE) of the surface region of UO2 single crystals, prepared by the hydrothermal synthesis technique, were obtained from temperature-dependent x-ray photoemission in the temperature range of 300 K–623 K. A lattice stiffening transition, characterized by different regions of different effective Debye temperature, 500 ± 59 K below 475 K and 165 ± 21 K above 475 K is identified. A comparison of the temperature dependence of the effective UO2 Debye temperature, with the changes in the lattice expansion coefficient for UO2, support strong lattice-phonon interaction arising from the Jahn–Teller distortion

Piecing together the puzzle of NGC 5253: abundances, kinematics and WR stars

We present Gemini-S/GMOS-IFU optical spectroscopy of four regions near the centre of the nearby (3.8 Mpc) dwarf starburst galaxy NGC 5253. This galaxy is famous for hosting a radio supernebula containing two deeply embedded massive super star clusters, surrounded by a region of enhanced nitrogen abundance that has been linked to the presence of WR stars. We detected 11 distinct sources of red WR bump (CIV) emission over a 20" (~350 pc) area, each consistent with the presence of ~1 WCE-type star. WC stars are not found coincident with the supernebula, although WN stars have previously been detected here. We performed a multi-component decomposition of the H\alpha\ line across all four fields and mapped the kinematics of the narrow and broad (FWHM = 100-250 km/s) components. These maps paint a picture of localised gas flows, as part of multiple overlapping bubbles and filaments driven by the star clusters throughout the starburst. We confirm the presence of a strong H\alpha\ velocity gradient over ~4.5" (~80 pc) coincident with the region of N/O enhancement, and high gas density known from previous study, and interpret this as an accelerating ionized gas outflow from the supernebula clusters. We measure the ionized gas abundances in a number of regions in the outer IFU positions and combine these with measurements from the literature to assess the radial abundance distribution. We find that the O/H and N/H profiles are consistent with being flat. Only the central 50 pc exhibits the well-known N/O enhancement, and we propose that the unusually high densities/pressures in the supernebula region have acted to impede the escape of metal-enriched hot winds from the star clusters and allow them to mix with the cooler phases, thus allowing these freshly processed chemicals to be seen in the optical.Comment: 16 pages, accepted to A&

Male Infertility is a Women\u27s Health Issue-Research and Clinical Evaluation of Male Infertility Is Needed

Infertility is a devastating experience for both partners as they try to conceive. Historically, when a couple could not conceive, the woman has carried the stigma of infertility; however, men and women are just as likely to contribute to the couple\u27s infertility. With the development of assisted reproductive technology (ART), the treatment burden for male and unexplained infertility has fallen mainly on women. Equalizing this burden requires reviving research on male infertility to both improve treatment options and enable natural conception. Despite many scientific efforts, infertility in men due to sperm dysfunction is mainly diagnosed by a semen analysis. The semen analysis is limited as it only examines general sperm properties such as concentration, motility, and morphology. A diagnosis of male infertility rarely includes an assessment of internal sperm components such as DNA, which is well documented to have an impact on infertility, or other components such as RNA and centrioles, which are beginning to be adopted. Assessment of these components is not typically included in current diagnostic testing because available treatments are limited. Recent research has expanded our understanding of sperm biology and suggests that these components may also contribute to the failure to achieve pregnancy. Understanding the sperm\u27s internal components, and how they contribute to male infertility, would provide avenues for new therapies that are based on treating men directly for male infertility, which may enable less invasive treatments and even natural conception

Cost and cost-effectiveness of soil-transmitted helminth treatment programmes : systematic review and research needs

Background In this time of rapidly expanding mass drug administration (MDA) coverage and the new commitments for soil-transmitted helminth (STH) control, it is essential that resources are allocated in an efficient manner to have the greatest impact. However, many questions remain regarding how best to deliver STH treatment programmes; these include which age-groups should be targeted and how often. To perform further analyses to investigate what the most cost-effective control strategies are in different settings, accurate cost data for targeting different age groups at different treatment frequencies (in a range of settings) are essential. Methods Using the electronic databases PubMed, MEDLINE, and ISI Web of Knowledge, we perform a systematic review of costing studies and cost-effectiveness evaluations for potential STH treatment strategies. We use this review to highlight research gaps and outline the key future research needs. Results We identified 29 studies reporting costs of STH treatment and 17 studies that investigated its cost-effectiveness. The majority of these pertained to programmes only targeting school-aged children (SAC), with relatively few studies investigating alternative preventive chemotherapy (PCT) treatment strategies. The methods of cost data collection, analysis and reporting were highly variable among the different studies. Only four of the costing studies were found to have high applicability for use in forthcoming economic evaluations. There are also very few studies quantifying the costs of increasing the treatment frequency. Conclusions The absence of cost data and inconsistencies in the collection and analysis methods constitutes a major research gap for STH control. Detailed and accurate costs of targeting different age groups or increasing treatment frequency will be essential to formulate cost-effective public health policy. Defining the most cost-effective control strategies in different settings is of high significance during this period of expanding MDA coverage and new resource commitments for STH control

Analysis of the population-level impact of co-administering ivermectin with albendazole or mebendazole for the control and elimination of Trichuris trichiura.

INTRODUCTION: Soil-transmitted helminth (STH) infections are predominately controlled by providing children with preventive chemotherapy with either albendazole or mebendazole. However, neither has a high efficacy against Trichuris trichiura. This low efficacy limits the overall effectiveness of the current STH control programmes against T. trichiura. It has been demonstrated that co-administering ivermectin with albendazole or mebendazole significantly increases the efficacy of current treatments, which may increase the overall effectiveness of control programmes. METHODS: Using a STH transmission mathematical model, we evaluated the potential impact of co-administering ivermectin with albendazole or mebendazole to treat T. trichiura within a preventive chemotherapy programme targeting children (2-15 year olds). We evaluated the impact in terms of reduction in prevalent infections, mean worm burden, and prevalence of heavy infections. RESULTS: Although the current treatment strategy reduced T. trichiura worm burden and prevalence of heavy infections, due to their poor efficacy the long term impact of preventive chemotherapy for children was smaller compared to the other STH. Co-administering ivermectin increased the projected impact of the preventive chemotherapy programme in terms of all three of the explored metrics, practically in high transmission settings. Furthermore, ivermectin co-administration greatly increased the feasibility of and timeframe for breaking transmission. CONCLUSIONS: Co-administering ivermectin notably increased the projected impact of preventive chemotherapy in high transmission settings and increased the feasibility for breaking transmission. This has important implications for control programmes, some of which may be shifting focus from morbidity control to interruption of transmission, and some of which may be logistically unable to provide preventive chemotherapy twice a year as recommended. However, the benefit of co-administering ivermectin is limited by the fact that 2-5 year olds are often ineligible to receive treatment

Analysis of the population-level impact of co-administering ivermectin with albendazole or mebendazole for the control and elimination of Trichuris trichiura

Introduction: Soil-transmitted helminth (STH) infections are predominately controlled by providing children with preventive chemotherapy with either albendazole or mebendazole. However, neither has a high efficacy against Trichuris trichiura. This low efficacy limits the overall effectiveness of the current STH control programmes against T. trichiura. It has been demonstrated that co-administering ivermectin with albendazole or mebendazole significantly increases the efficacy of current treatments, which may increase the overall effectiveness of control programmes. Methods: Using a STH transmission mathematical model, we evaluated the potential impact of co-administering ivermectin with albendazole or mebendazole to treat T. trichiura within a preventive chemotherapy programme targeting children (2–15 year olds). We evaluated the impact in terms of reduction in prevalent infections, mean worm burden, and prevalence of heavy infections. Results: Although the current treatment strategy reduced T. trichiura worm burden and prevalence of heavy infections, due to their poor efficacy the long term impact of preventive chemotherapy for children was smaller compared to the other STH. Co-administering ivermectin increased the projected impact of the preventive chemotherapy programme in terms of all three of the explored metrics, practically in high transmission settings. Furthermore, ivermectin co-administration greatly increased the feasibility of and timeframe for breaking transmission. Conclusions: Co-administering ivermectin notably increased the projected impact of preventive chemotherapy in high transmission settings and increased the feasibility for breaking transmission This has important implications for control programmes, some of which may be shifting focus from morbidity control to interruption of transmission, and some of which may be logistically unable to provide preventive chemotherapy twice a year as recommended. However, the benefit of co-administering ivermectin is limited by the fact that 2–5 year olds are often ineligible to receive treatment