Black hole lasers, a mode analysis

We show that the black hole laser effect discovered by Corley & Jacobson should be described in terms of frequency eigenmodes that are spatially bound. The spectrum contains a discrete and finite set of complex frequency modes which appear in pairs and which encode the laser effect. In addition, it contains real frequency modes that form a continuous set when space is infinite, and which are only elastically scattered, i.e., not subject to any Bogoliubov transformation. The quantization is straightforward, but the calculation of the asymptotic fluxes is rather involved. When the number of complex frequency modes is small, our expressions differ from those given earlier. In particular, when the region between the horizons shrinks, there is a minimal distance under which no complex frequency mode exists, and no radiation is emitted. Finally, we relate this effect to other dynamical instabilities found for rotating black holes and in electric fields, and we give the conditions to get this type of instability.Comment: 19 pages, 3 figures, main changes: new figure and new Sec.6 `conditions for having a laser effect', final version accepted in PR

Monte Carlo simulation of the transmission of measles: Beyond the mass action principle

We present a Monte Carlo simulation of the transmission of measles within a population sample during its growing and equilibrium states by introducing two different vaccination schedules of one and two doses. We study the effects of the contact rate per unit time $\xi$ as well as the initial conditions on the persistence of the disease. We found a weak effect of the initial conditions while the disease persists when $\xi$ lies in the range 1/L-10/L ($L$ being the latent period). Further comparison with existing data, prediction of future epidemics and other estimations of the vaccination efficiency are provided. Finally, we compare our approach to the models using the mass action principle in the first and another epidemic region and found the incidence independent of the number of susceptibles after the epidemic peak while it strongly fluctuates in its growing region. This method can be easily applied to other human, animals and vegetable diseases and includes more complicated parameters.Comment: 15 pages, 4 figures, 1 table, Submitted to Phys.Rev.

Interannual variation patterns of total ozone and lower stratospheric temperature in observations and model simulations

We report results from a multiple linear regression analysis of long-term total ozone observations (1979 to 2000, by TOMS/SBUV), of temperature reanalyses (1958 to 2000, NCEP), and of two chemistry-climate model simulations (1960 to 1999, by ECHAM4.L39(DLR)/CHEM (=E39/C), and MAECHAM4-CHEM). The model runs are transient experiments, where observed sea surface temperatures, increasing source gas concentrations (CO2, CFCs, CH4, N2O, NOx), 11-year solar cycle, volcanic aerosols and the quasi-biennial oscillation (QBO) are all accounted for. MAECHAM4-CHEM covers the atmosphere from the surface up to 0.01 hPa ( 80 km). For a proper representation of middle atmosphere (MA) dynamics, it includes a parametrization for momentum deposition by dissipating gravity wave spectra. E39/C, on the other hand, has its top layer centered at 10 hPa ( 30 km). It is targeted on processes near the tropopause, and has more levels in this region. Despite some problems, both models generally reproduce the observed amplitudes and much of the observed lowlatitude patterns of the various modes of interannual variability in total ozone and lower stratospheric temperature. In most aspects MAECHAM4-CHEM performs slightly better than E39/C. MAECHAM4-CHEM overestimates the longterm decline of total ozone, whereas E39/C underestimates the decline over Antarctica and at northern mid-latitudes. The true long-term decline in winter and spring above the Correspondence to: W. Steinbrecht ([email protected]) Arctic may be underestimated by a lack of TOMS/SBUV observations in winter, particularly in the cold 1990s. Main contributions to the observed interannual variations of total ozone and lower stratospheric temperature at 50 hPa come from a linear trend (up to −10 DU/decade at high northern latitudes, up to −40 DU/decade at high southern latitudes, and around −0.7 K/decade over much of the globe), from the intensity of the polar vortices (more than 40 DU, or 8 K peak to peak), the QBO (up to 20 DU, or 2 K peak to peak), and from tropospheric weather (up to 20 DU, or 2 K peak to peak). Smaller variations are related to the 11-year solar cycle (generally less than 15 DU, or 1 K), or to ENSO (up to 10 DU, or 1 K). These observed variations are replicated well in the simulations. Volcanic eruptions have resulted in sporadic changes (up to −30 DU, or +3 K). At low latitudes, patterns are zonally symmetric. At higher latitudes, however, strong, zonally non-symmetric signals are found close to the Aleutian Islands or south of Australia. Such asymmetric features appear in the model runs as well, but often at different longitudes than in the observations. The results point to a key role of the zonally asymmetric Aleutian (or Australian) stratospheric anti-cyclones for interannual variations at high-latitudes, and for coupling between polar vortex strength, QBO, 11-year solar cycle and ENSO

Impact of free on-site vaccine and/or healthcare workers training on hepatitis B vaccination acceptability in high-risk subjects: a pre-post cluster randomized study

AbstractDespite recommendations for adults at high-risk of hepatitis B virus (HBV) infection, HBV vaccine uptake remains low in this population. A pre-post randomized cluster study was conducted to evaluate the impact of on-site free HBV vaccine availability and/or healthcare worker training on HBV vaccination acceptability in high-risk adults consulting in 12 free and anonymous HIV and hepatitis B/C testing centres (FATC). The FATC were randomly allocated into three groups receiving a different intervention: training on HBV epidemiology, risk factors and vaccination (Group A), free vaccination in the FATC (Group B), both interventions (Group C). The main outcomes were the increase in HBV vaccination acceptability (receipt of at least one dose of vaccine) and vaccine coverage (receipt of at least two doses of vaccine) after intervention. Respectively, 872 and 809 HBV-seronegative adults at high-risk for HBV infection were included in the pre- and post-intervention assessments. HBV vaccination acceptability increased from 14.0% to 75.6% (p <0.001) in Group B and from 17.1% to 85.8% (p <0.001) in Group C and HBV vaccine coverage increased from 9.4% to 48.8% (p <0.001) in Group B and from 11.2% to 41.0% (p <0.001) in Group C. The association of training and free on-site vaccine availability was more effective than free on-site vaccine availability alone to increase vaccination acceptability (ratio 1.14; from 1.02 to 1.26; p 0.017). No effect of training alone was observed. These results support the policy of making HBV vaccine available in health structures attended by high-risk individuals. Updating healthcare workers’ knowledge on HBV virus and its prevention brings an additional benefit to vaccination acceptability

Osmotic adjustment, stomata morphology and function show contrasting responses to water stress in mesic and hydric grasses under elevated CO2 concentration

The physiological response of two species of grasses with C3 and C4 mechanisms syndromes, Napier grass (Pennisetum purpureum Schumach × Pennisetum glaucum (L.) R. Br) and hydric common reed grass (Phragmites australis (Cav.) Trin. Ex Steud) was examined under ambient (aCO2) and elevated CO2 (eCO2), in combination with water and temperature stress treatments. Under eCO2 and subjected to water and temperature stress, the Napier grass maintained higher daytime leaf water potential (LWP) by reducing transpiration (E) and executing larger osmotic adjustment (OA) at an average of 0.85 MPa compared with 0.42 MPa for common reed; carbon assimilation (PN) was thus higher for the Napier grass. Under aCO2 and low temperature, water stress induced no significant differences in OA between the grasses, but Napier grass still had higher PN than that of common reed. Recovery in LWP and PN following re-watering of water-stressed plants was more rapid in Napier grass than that in the common reed; the former had also higher water-use efficiency due to its low specific water use (water use/leaf area) that was just a fraction (less than 6%) that of the common reed. Exposure of common reed to eCO2 reduced stomata number, but increased it in the Napier grass, especially when subjected to water stress and high temperature. Exposure to eCO2 enhanced OA capacity and E control in Napier grass resulting in superior physiological profile over the common reed subjected to water and heat stress

Stakeholder engagement in eight comparative effectiveness trials in African Americans and Latinos with asthma

BACKGROUND: The effects of stakeholder engagement, particularly in comparative effectiveness trials, have not been widely reported. In 2014, eight comparative effectiveness studies targeting African Americans and Hispanics/Latinos with uncontrolled asthma were funded by the Patient-Centered Outcomes Research Institute (PCORI) as part of its Addressing Disparities Program. Awardees were required to meaningfully involve patients and other stakeholders. Using specific examples, we describe how these stakeholders substantially changed the research protocols and in other ways participated meaningfully as full partners in the development and conduct of the eight studies. METHODS: Using the method content analysis of cases, we identified themes regarding the types of stakeholders, methods of engagement, input from the stakeholders, changes made to the research protocols and processes, and perceived benefits and challenges of the engagement process. We used summaries from meetings of the eight teams, results from an engagement survey, and the final research reports as our data source to obtain detailed information. The descriptive data were assessed by multiple reviewers using inductive and deductive qualitative methods and discussed in the context of engagement literature. RESULTS: Stakeholders participated in the planning, conduct, and dissemination phases of all eight asthma studies. All the studies included clinicians and community representatives as stakeholders. Other stakeholders included patients with asthma, their caregivers, advocacy organizations, and health-system representatives. Engagement was primarily by participation in advisory boards, although six of the eight studies (75%) also utilized focus groups and one-on-one interviews. Difficulty finding a time and location to meet was the most reported challenge to engagement, noted by four of the eight teams (50%). Other reported challenges and barriers to engagement included recruitment of stakeholders, varying levels of enthusiasm among stakeholders, controlling power dynamics, and ensuring that stakeholder involvement was reflected and had true influence on the project. CONCLUSION: Engagement-driven modifications led to specific changes in study design and conduct that were felt to have increased enrollment and the general level of trust and support of the targeted communities. The level of interaction described, between investigators and stakeholders in each study and between investigator-stakeholder groups, is-we believe-unprecedented and may provide useful guidance for other studies seeking to improve the effectiveness of community-driven research

Phylogeny of Cyperaceae Based on DNA Sequence Data–a New rbcL Analysis

Since the Monocots II meeting in 1998, significant new data have been published that enhance our systematic knowledge of Cyperaceae. Phylogenetic studies in the family have also progressed steadily. For this study, a parsimony analysis was carried out using all rbcL sequences currently available for Cyperaceae, including data for two new genera. One of the four subfamilies (Caricoideae) and seven of the 14 tribes (Bisboeckelereae, Cariceae, Cryptangieae, Dulichieae, Eleocharideae, Sclerieae, Trilepideae) are monophyletic. Subfamily Mapanioideae and tribe Chrysitricheae are monophyletic if, as the evidence suggests, Hellmuthia is considered a member of Cypereae. Some other features of our analysis include: well-supported Trilepideae and Sclerieae–Bisboeckelereae clades; a possible close relationship between Cryptangieae and Schoeneae; polyphyletic tribes Schoeneae and Scirpeae; the occurrence of Cariceae within the Dulichieae–Scirpeae clade, and a strongly supported clade, representing Cyperus and allied genera in Cypereae, sister to a poorly supported Ficinia–Hellmuthia– Isolepis–Scirpoides clade. Such patterns are consistent with other studies based on DNA sequence data. One outcome may be that only two subfamilies, Mapanioideae and Cyperoideae, are recognized. Much further work is needed, with efforts carefully coordinated among researchers. The work should focus on obtaining morphological and molecular data for all genera in the family

Demographic and Clinical Factors Associated with Response to Smallpox Vaccine in Preimmunized Volunteers

CONTEXT: In March 2003, the French Ministry of Health implemented a program on preparedness and response to a biological attack using smallpox as weapon. This program included the establishment of a preoutbreak national team that could be revaccinated against smallpox. OBJECTIVE: To identify demographic and clinical factors associated with vaccination success defined as the presence of a pustule at the inoculation site at day 8 (days 7-9), with an undiluted vaccinia virus derived from a Lister strain among preimmunized volunteers. VOLUNTEERS AND METHODS: From March 2003 to November 2006, we have studied prospectively 226 eligible volunteers. Demographic data were recorded for each volunteer (age, sex, number of previously smallpox vaccinations and date of the last vaccination). Smallpox vaccine adverse reactions were diagnosed on the basis of clinical examination performed at days 0, 7, 14, 21 and 28 after revaccination. RESULTS: A total of 226 volunteers (sex ratio H/F = 2.7) were revaccinated. Median age was 45 years (range: 27-63 yrs). All volunteers completed follow-up. Median number of vaccinations before revaccination was 2 (range: 1-8). The median delay between time of the study and the last vaccination was 29 years (range; 18-60 yrs). Sixty-one volunteers (27%) experienced one (n = 40) or more (n = 21) minor side effects during the 2-14 days after revaccination. Successful vaccination was noted in 216/226 volunteers (95.6%) at day 8 and the median of the pustule diameter was 5 mm (range: 1-20 mm). Size of the pustule at day 8 was correlated with age (p = 0.03) and with the presence of axillary adenopathy after revaccination (p = 0.007). Sex, number of prior vaccinations, delay between the last vaccination and revaccination, and local or systemic side effects with the exception of axillary adenopathy, were not correlated with the size of the pustule at day 8. CONCLUSIONS: Previously vaccinated volunteers can be successfully revaccinated with the Lister strain

A new classification of Cyperaceae (Poales) supported by phylogenomic data

Cyperaceae (sedges) are the third largest monocot family and are of considerable economic and ecological importance. Sedges represent an ideal model family to study evolutionary biology because of their species richness, global distribution, large discrepancies in lineage diversity, broad range of ecological preferences, and adaptations including multiple origins of C4 photosynthesis and holocentric chromosomes. Goetghebeur’s seminal work on Cyperaceae published in 1998 provided the most recent complete classification at tribal and generic level, based on a morphological study of Cyperaceae inflorescence, spikelet, flower and embryo characters plus anatomical and other information. Since then, several family‐level molecular phylogenetic studies using Sanger sequence data have been published. Here, more than 20 years after the last comprehensive classification of the family, we present the first family‐wide phylogenomic study of Cyperaceae based on targeted sequencing using the Angiosperms353 probe kit sampling 311 accessions. Additionally, 62 accessions available from GenBank were mined for overlapping reads and included in the phylogenomic analyses. Informed by this backbone phylogeny, a new classification for the family at the tribal, subtribal and generic levels is proposed. The majority of previously recognized suprageneric groups are supported, and for the first time we establish support for tribe Cryptangieae as a clade including the genus Koyamaea. We provide a taxonomic treatment including identification keys and diagnoses for the 2 subfamilies, 24 tribes and 10 subtribes and basic information on the 95 genera. The classification includes five new subtribes in tribe Schoeneae: Anthelepidinae, Caustiinae, Gymnoschoeninae, Lepidospermatinae and Oreobolinae. This article is protected by copyright. All rights reserved