1,425 research outputs found

    Acoustically Levitated Whispering-Gallery Mode Microlasers

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    Acoustic levitation has become a crucial technique for contactless manipulation in several fields, particularly in biological applications. However, its application in the photonics field remains largely unexplored. In this study, we implement an affordable and innovative phased-array levitator that enables stable trapping in the air of micrometer dye-doped droplets, thereby enabling the creation of microlasers. For the first time, this paper presents a detailed performance of the levitated microlaser cavity, supported by theoretical analysis concerning the hybrid technology based on the combination of whispering-gallery modes and acoustic fields. The pressure field distribution inside the acoustic cavity is numerically solved and qualitatively matched with the schlieren deflectometry technique. The optical lasing features of the levitated microlasers are highly comparable with those devices based On-a-Chip registering maximum Q-factors of ~ 105, and minimum lasing thresholds ~ 150 nJ cm−2. The emission comb is explained as a sum of multiple individual-supported whispering-gallery modes. The use of novel touchless micrometric lasers, produced with an acoustic levitator brings new technological opportunities based on photonic-acoustic technological platforms

    Results from the Super Cryogenic Dark Matter Search (SuperCDMS) experiment at Soudan

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    We report the result of a blinded search for Weakly Interacting Massive Particles (WIMPs) using the majority of the SuperCDMS Soudan dataset. With an exposure of 1690 kg days, a single candidate event is observed, consistent with expected backgrounds. This analysis (combined with previous Ge results) sets an upper limit on the spin-independent WIMP--nucleon cross section of 1.4×10441.4 \times 10^{-44} (1.0×10441.0 \times 10^{-44}) cm2^2 at 46 GeV/c2c^2. These results set the strongest limits for WIMP--germanium-nucleus interactions for masses >>12 GeV/c2c^2

    Evaluación del impacto de una intervención para mejorar las coberturas de vacunación frente a neumococo en pacientes con VIH

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    Fundamentos: Las personas infectadas por el vi-rus de la inmunodeficiencia humana (VIH) presentan riesgo elevado de sufrir la enfermedad neumocócica invasiva, motivo por el que se recomienda su vacuna-ción frente al neumococo. El objetivo de este trabajo fue evaluar el impacto de implementar una consulta hospitalaria de vacunas en las coberturas de vacuna-ción de estos pacientes. Métodos: Se elaboró un estudio cuasiexperimental sin grupo control, de tipo antes/después, en el que se realizó un muestreo de casos consecutivos de pacientes con VIH remitidos a nuestra consulta entre el 1 noviembre de 2014 y el 30 junio de 2018. Las coberturas en el momento de la fecha de la cita para la valoración de su estado vacunal (en nuestra consulta) y después de ser atendido se compararon usando la prueba chi-cuadrado. Como referencia se utilizaron las del momento de la fecha de la primera cita. Resultados: Se analizaron 209 pacientes, en los que se obtuvieron mejoras estadísticamente signifi-cativas en sus coberturas vacunales: 2, 9% en el mo-mento de la fecha de la cita para la valoración en nuestra consulta y 88% después de ser atendidos en nuestra consulta (RR [IC95%]= 30, 7 [13, 92-67, 58]) para la vacuna antineumocócica conjugada 13-valen-te, y 16, 3% en el momento de la primera cita y 83, 7% después de ser atendidos en nuestra consulta (RR [IC95%]=5, 2 [3, 76-7, 04]) para la vacuna antineumo-cócica polisacárida 23-valente. Conclusiones: Implementar una consulta hospitalaria de vacunas representa una intervención efectiva para mejorar las coberturas de vacunación frente al neumococo en pacientes con VIH. Background: People affected by the human immunodeficiency virus (HIV) have a higher risk of invasive pneumococcal disease. Therefore, vaccination against streptococcus pneumoniae is recommended for that group. The objective of this study was to analyze the impact of implementing a hospital appointment to assess vaccination status as part of the vaccination schedule of HIV patients. Methods: We carried out a quasi-experimental uncontrolled before and after study with a sampling of consecutive cases of HIV patients referred to our department from November 1, 2014 to June 30, 2018. The study compared the vaccination coverage on the date of the appointment for an assessment of their vaccination status in our department and after the appointment. The analysis used the chi-squared test and the values on the date of the first appointment were taken as a reference. Results: 209 patients were analyzed, and a statistically significant improvement was observed regarding their vaccination coverage: 2.9% of the patients had been vaccinated on the date in which they made an appointment for assessment by our department, and 88.0% were vaccinated after they left (OR [95%CI]: 30.7 [13.92-67.58]) with the 13-valent pneumococcal conjugate vaccine; and 16.3% had been vaccinated on the date they made the first appointment vs. 83.7% after they came to the appointment (OR [95%CI]: 5.2 [3.76-7.04]) with the 23-valent polysaccharide pneumococcal vaccine. Conclusions: Implementing a hospital appointment for vaccination is an effective intervention to improve vaccination coverage against streptococcus pneumoniae in HIV patients

    Whole cell inactivated autogenous vaccine effectively protects red Nile tilapia (Oreochromis niloticus) against francisellosis via intraperitoneal injection

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    Francisella noatunensis subsp. orientalis is a pathogen of tilapia and other warm‐water fish for which no vaccines are commercially available. In this study, a whole cell formalin‐inactivated vaccine was developed for the first time using the highly virulent isolate STIR‐GUS‐F2f7 and the oil‐based adjuvant Montanide™ ISA 763A VG. The efficacy of the vaccine was assessed in red Nile tilapia via intraperitoneal (i.p.) injection using homologous experimental infection and correlates of protection such as seral antibody production and bacterial loads in the spleen. For immunization, fish were i.p. injected with 0.1 ml of the vaccine, the adjuvant alone or PBS. At 840 degree days post‐vaccination, all fish were i.p. injected with 4.0 × 103 CFU/fish of pathogenic bacteria. The RPS at the end of the trial was 100% in the vaccinated group with significantly higher survival than in the adjuvant and control groups. The RPS in the adjuvant group was 42%, and no significant difference was seen in survival between this and the PBS group. Moreover, significantly higher antibody titres in the serum and significantly lower bacterial loads in the spleen were detected in the vaccinated fish by ELISA and qPCR, respectively. These findings highlight the potential of autogenous vaccines for controlling francisellosis in tilapia

    The Sensitivity of HAWC to High-Mass Dark Matter Annihilations

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    The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.Comment: 15 pages, 4 figures, version to be published in PR

    Methods to estimate aboveground wood productivity from long-term forest inventory plots

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    Forest inventory plots are widely used to estimate biomass carbon storage and its change over time. While there has been much debate and exploration of the analytical methods for calculating biomass, the methods used to determine rates of wood production have not been evaluated to the same degree. This affects assessment of ecosystem fluxes and may have wider implications if inventory data are used to parameterise biospheric models, or scaled to large areas in assessments of carbon sequestration. Here we use a dataset of 35 long-term Amazonian forest inventory plots to test different methods of calculating wood production rates. These address potential biases associated with three issues that routinely impact the interpretation of tree measurement data: (1) changes in the point of measurement (POM) of stem diameter as trees grow over time; (2) unequal length of time between censuses; and (3) the treatment of trees that pass the minimum diameter threshold (“recruits”). We derive corrections that control for changing POM height, that account for the unobserved growth of trees that die within census intervals, and that explore different assumptions regarding the growth of recruits during the previous census interval. For our dataset we find that annual aboveground coarse wood production (AGWP; in Mg ha−1 year−1 of dry matter) is underestimated on average by 9.2% if corrections are not made to control for changes in POM height. Failure to control for the length of sampling intervals results in a mean underestimation of 2.7% in annual AGWP in our plots for a mean interval length of 3.6 years. Different methods for treating recruits result in mean differences of up to 8.1% in AGWP. In general, the greater the length of time a plot is sampled for and the greater the time elapsed between censuses, the greater the tendency to underestimate wood production. We recommend that POM changes, census interval length, and the contribution of recruits should all be accounted for when estimating productivity rates, and suggest methods for doing this.European UnionUK Natural Environment Research CouncilGordon and Betty Moore FoundationCASE sponsorship from UNEP-WCMCRoyal Society University Research FellowshipERC Advanced Grant “Tropical Forests in the Changing Earth System”Royal Society Wolfson Research Merit Awar
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