3,508 research outputs found

    Nongassing NiCd battery cell

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    Method of constructing nickel cadmium batteries prevents excessive gas buildup and allows hermetic sealing of battery for increased service life and reduced maintenance cost

    Chandra observations of the HII complex G5.89-0.39 and TeV gamma-ray source HESSJ1800-240B

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    We present the results of our investigation, using a Chandra X-ray observation, into the stellar population of the massive star formation region G5.89-0.39, and its potential connection to the coincident TeV gamma-ray source HESSJ1800-240B. G5.89-0.39 comprises two separate HII regions G5.89-0.39A and G5.89-0.39B (an ultra-compact HII region). We identified 159 individual X-ray point sources in our observation using the source detection algorithm \texttt{wavdetect}. 35 X-ray sources are associated with the HII complex G5.89-0.39. The 35 X-ray sources represent an average unabsorbed luminosity (0.3-10\,keV) of ∌1030.5\sim10^{30.5}\,erg/s, typical of B7-B5 type stars. The potential ionising source of G5.89-0.39B known as Feldt's star is possibly identified in our observation with an unabsorbed X-ray luminosity suggestive of a B7-B5 star. The stacked energy spectra of these sources is well-fitted with a single thermal plasma APEC model with kT∌\sim5\,keV, and column density NH=2.6×1022_{\rm H}=2.6\times10^{22}\,cm−2^{-2} (AV∌10_{\rm V}\sim 10). The residual (source-subtracted) X-ray emission towards G5.89-0.39A and B is about 30\% and 25\% larger than their respective stacked source luminosities. Assuming this residual emission is from unresolved stellar sources, the total B-type-equivalent stellar content in G5.89-0.39A and B would be 75 stars, consistent with an earlier estimate of the total stellar mass of hot stars in G5.89-0.39. We have also looked at the variability of the 35 X-ray sources in G5.89-0.39. Ten of these sources are flagged as being variable. Further studies are needed to determine the exact causes of the variability, however the variability could point towards pre-main sequence stars. Such a stellar population could provide sufficient kinetic energy to account for a part of the GeV to TeV gamma-ray emission in the source HESSJ1800-240B.Comment: 34 pages, 9 figure

    Inverse scattering method for square matrix nonlinear Schr\"odinger equation under nonvanishing boundary conditions

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    Matrix generalization of the inverse scattering method is developed to solve the multicomponent nonlinear Schr\"odinger equation with nonvanishing boundary conditions. It is shown that the initial value problem can be solved exactly. The multi-soliton solution is obtained from the Gel'fand--Levitan--Marchenko equation.Comment: 25 pages, 2 figures; (v2) title changed, typos in equations corrected, sec.3.1 modified and extende

    Constraints on cosmic-ray efficiency in the supernova remnant RCW 86 using multi-wavelength observations

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    Several young supernova remnants (SNRs) have recently been detected in the high-energy and very-high-energy gamma-ray domains. As exemplified by RX J1713.7-3946, the nature of this emission has been hotly debated, and direct evidence for the efficient acceleration of cosmic-ray protons at the SNR shocks still remains elusive. We analyzed more than 40 months of data acquired by the Large Area Telescope (LAT) on-board the Fermi Gamma-Ray Space Telescope in the HE domain, and gathered all of the relevant multi-wavelength (from radio to VHE gamma-rays) information about the broadband nonthermal emission from RCW 86. For this purpose, we re-analyzed the archival X-ray data from the ASCA/Gas Imaging Spectrometer (GIS), the XMM-Newton/EPIC-MOS, and the RXTE/Proportional Counter Array (PCA). Beyond the expected Galactic diffuse background, no significant gamma-ray emission in the direction of RCW 86 is detected in any of the 0.1-1, 1-10 and 10-100 GeV Fermi-LAT maps. In the hadronic scenario, the derived HE upper limits together with the HESS measurements in the VHE domain can only be accommodated by a spectral index Gamma <= 1.8, i.e. a value in-between the standard (test-particle) index and the asymptotic limit of theoretical particle spectra in the case of strongly modified shocks. The interpretation of the gamma-ray emission by inverse Compton scattering of high energy electrons reproduces the multi-wavelength data using a reasonable value for the average magnetic field of 15-25 muG. For these two scenarios, we assessed the level of acceleration efficiency. We discuss these results in the light of existing estimates of the magnetic field strength, the effective density and the acceleration efficiency in RCW 86.Comment: Accepted for publication in A&A; 10 pages and 4 figure

    Age and growth of swordfish (Xiphias gladius) caught by the Hawaii-based pelagic longline fishery

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    We verified the age and growth of swordfish (Xiphias gla-dius) by comparing ages determined from annuli in fin ray sections with daily growth increments in otoliths. Growth of swordfish of exploitable sizes is described on the basis of annuli present in cross sections of the second ray of the first anal fins of 1292 specimens (60−260 cm eye-to-fork length, EFL) caught in the region of the Hawaii-based pelagic longline fishery. The position of the initial fin ray annulus of swordfish was verified for the first time with the use of scanning electron micrographs of presumed daily growth increments present in the otoliths of juveniles. Fish growth through age 7 was validated by marginal increment analysis. Faster growth of females was confirmed, and the standard von Bertalanffy growth model was identified as the most parsimonious for describing growth in length for fish greater than 60 cm EFL. The observed growth of three fish, a year-old in size when first caught and then recaptured from 364 to1490 days later, is consistent with modeled growth for fish of this size range. Our novel approach to verifying age and growth should increase confidence in conducting an age-structured stock assessment for swordfish in the North Pacific Ocean

    Pulse Control of Decoherence in a Qubit Coupled with a Quantum Environment

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    We study the time evolution of a qubit linearly coupled with a quantum environment under a sequence of short pi pulses. Our attention is focused on the case where qubit-environment interactions induce the decoherence with population decay. We assume that the environment consists of a set of bosonic excitations. The time evolution of the reduced density matrix for the qubit is calculated in the presence of periodic short pi pulses. We confirm that the decoherence is suppressed if the pulse interval is shorter than the correlation time for qubit-environment interactions.Comment: 5 pages, 2figure

    Gamma ray emission from SNR RX J1713.7-3946 and the origin of galactic cosmic rays

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    We calculate the flux of non-thermal radiations from the supernova remnant RX J1713.7-3946 in the context of the non-linear theory of particle acceleration at shocks, which allows us to take into account self-consistently the dynamical reaction of the accelerated particles, the generation of magnetic fields in the shock proximity and the dynamical reaction of the magnetic field on the plasma. When the fraction of particles which get accelerated is of order ∌10−4\sim 10^{-4}, we find that the strength of the magnetic field obtained as a result of streaming instability induced by cosmic rays is compatible with the interpretation of the X-ray emitting filaments being produced by strong synchrotron losses in ∌100ÎŒG\sim 100 \mu G magnetic fields. If the X-ray filaments are explained in alternative ways, the constraint on the magnetic field downstream of the shock disappears and the HESS data can be marginally fit with ICS of relativistic electrons off a complex population of photons, tailored to comprise CMB and ambient IR/Optical photons. The fit, typically poor at the highest energies, requires a large density of target photons within the remnant; only a fraction of order ∌10−6\sim 10^{-6} of the background particles gets accelerated; the local magnetic field is of order ∌20ÎŒG\sim 20\mu G and the maximum energy of protons is much lower than the knee energy. Current HESS gamma ray observations combined with recent X-ray observations by Suzaku do not allow as yet to draw a definitive conclusion on whether RX J1713.7-3946 is an efficient cosmic ray accelerator, although at the present time a hadronic interpretation of HESS data seems more likely. We discuss the implications of our results for the GLAST gamma ray telescope, which should be able to discriminate the two scenarios discussed above.Comment: Accepted for Publication in MNRA

    Topological-charge anomalies in supersymmetric theories with domain walls

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    Domain walls in 1+2 dimensions are studied to clarify some general features of topological-charge anomalies in supersymmetric theories, by extensive use of a superfield supercurrent. For domain walls quantum modifications of the supercharge algebra arise not only from the short-distance anomaly but also from another source of long-distance origin, induced spin in the domain-wall background, and the latter dominates in the sum. A close look into the supersymmetric trace identity, which naturally accommodates the central-charge anomaly and its superpartners, shows an interesting consequence of the improvement of the supercurrent: Via an improvement the anomaly in the central charge can be transferred from induced spin in the fermion sector to an induced potential in the boson sector. This fact reveals a dual character, both fermionic and bosonic, of the central-charge anomaly, which reflects the underlying supersymmetry. The one-loop superfield effective action is also constructed to verify the anomaly and BPS saturation of the domain-wall spectrum.Comment: 8 pages, Revte

    Probing the Pulsar Wind in the gamma-ray Binary System PSR B1259-63/SS 2883

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    The spectral energy distribution from the X-ray to the very high energy regime (>100>100 GeV) has been investigated for the Îł\gamma-ray binary system PSR B1259-63/SS2883 as a function of orbital phase within the framework of a simple model of a pulsar wind nebula. The emission model is based on the synchrotron radiation process for the X-ray regime and the inverse Compton scattering process boosting stellar photons from the Be star companion to the very high energy (100GeV-TeV) regime. With this model, the observed temporal behavior can, in principle, be used to probe the pulsar wind properties at the shock as a function of the orbital phase. Due to theoretical uncertainties in the detailed microphysics of the acceleration process and the conversion of magnetic energy into particle kinetic energy, the observed X-ray data for the entire orbit are fit using two different methods.Comment: 46 pages, 16 figures, accepted for publication in Ap

    Using a Hybrid Lecture and Small Group Standardized Patient Case to Teach the Inclusive Sexual History and Transgender Patient Care

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    Background: Previous negative experiences with the medical community often leave transgender people reluctant to seek needed medical treatment and preventive care. Inadequate training in transgender healthcare during all stages of medical education promotes the disparities experienced by this community. Undergraduate medical education is uniquely positioned to address these disparities by better preparing future physicians to provide inclusive care to transgender patients; however, curricular coverage of these topics remains inadequate. Methods: The second-year clinical skills course at the Herbert Wertheim College of Medicine includes a hybrid workshop consisting of a one-hour lecture about the components of an inclusive sexual history, followed by a 1.5 hour, faculty-facilitated small group session during which students interview a standardized patient playing the role of a transgender man with abdominal pain. During the session, students were provided with an optional, anonymous pre- and post-intervention survey assessing the impact of this workshop. Results: After the session, there was a statistically significant increase in students’ knowledge of the Create your own automated PDFs with JotForm PDF Editor 1 components of an inclusive sexual history, in the number of students who felt that their medical training had effectively prepared them to provide medical care for transgender patients, and in those who reported feeling comfortable gathering a sexual history from a transgender patient. Students overall reported a high level of satisfaction with the session and the standardized patient case. Conclusions: Our findings suggest that the hybrid-learning format of the sexual history workshop effectively improved students’ knowledge and confidence regarding transgender healthcare and sexual history taking. Although our case was acted by well-coached cis-gender standardized patients without the lived experiences of being transgender, students still reported that it provided a realistic opportunity to explore the nuances of transgender healthcare. While we demonstrated value in using cis-gender standardized patients, future directions of this project will explore the recruitment of transgender standardized patients.https://jdc.jefferson.edu/sexandgenderhealth/1027/thumbnail.jp
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