479 research outputs found

    Analysis of Fermi-LAT data from Tucana-II: Possible constraints on the Dark Matter models with an intriguing hint of a signal

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    Tucana-II (Tuc-II), a recently discovered and confirmed Ultra Faint Dwarf Spheroidal galaxy, has a high mass to light ratio as well as a large line-of-sight stellar velocity dispersion, thus making it an ideal candidate for an indirect dark matter (DM) search. In this paper, we have analyzed nine years of Ī³\gamma-ray data obtained from the \textit{Fermi}-LAT instrument from the direction of Tuc-II. The fact that a very weak significant Ī³\gamma-ray excess (2.2Ļƒ2.2\sigma) over the background of Tuc-II have been detected from the location of this galaxy. We have observed that this excess of Ī³\gamma-ray emission from the of location Tuc-II rises with longer periods of data. If WIMP pair annihilation is assumed for this faint emission, for bbĖ‰b\bar{b} annihilation channel the test statistics (TS) value peaks at DM mass āˆ¼\sim 14 GeV and for Ļ„+Ļ„āˆ’\tau^{+}\tau^{-} annihilation channel it peaks at DM mass 4 GeV. It is then called for an estimation of the 95%95\% confidence level upper limit of the possible velocity weighted self-annihilation cross-section of the DM particles (WIMPs) within Tuc-II by fitting the observed Ī³\gamma-ray flux with spectra expected for DM annihilation. The estimated upper limits of the cross-sections from Tuc-II are then compared with two other dwarf galaxies that are considered to be good DM candidates in several studies. We have also compared our results with the cross-sections obtained in various popular theoretical models of the WIMPs to find that our results impose reasonable tight constraints on the parameter spaces of those DM models. In the concluding section, we compared our results with the similar results obtained from a combined dSph analysis by the \textit{Fermi}-LAT collaboration as well as the results obtained from the studies of DM in the dwarf galaxies by the major ground-based Cherenkov experiments.Comment: 23 pages, 16 figures, 7 table

    Anesthetic management in a challenging case of primary pulmonary synovial sarcoma

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    Primary pulmonary synovial sarcoma is a very rare tumor. This tumor accounts for less than 0.5% of all lung neoplasia. While synovial sarcomas are commonly reported from periarticular tissues, they are often found in lung or thorax as a metastasis from an extrapulmonary primary. However, rarely they arise primarily from lung tissue. We report a case of primary pulmonary synovial sarcoma which was indenting the right side of the heart. He was managed with neoadjuvant chemotherapy followed by surgical resection. The anesthetic management was challenging. The focus was kept on stringent invasive as well as non-invasive monitoring of cardiac and respiratory parameters. The surgery was uneventful and the patient made a successful recovery.

    Mitigating the source-side channel vulnerability by characterization of photon statistics

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    Quantum key distribution (QKD) theoretically offers unconditional security. Unfortunately, the gap between theory and practice threatens side-channel attacks on practical QKD systems. Many well-known QKD protocols use weak coherent laser pulses to encode the quantum information. These sources differ from ideal single photon sources and follow Poisson statistics. Many protocols, such as decoy state and coincidence detection protocols, rely on monitoring the photon statistics to detect any information leakage. The accurate measurement and characterization of photon statistics enable the detection of adversarial attacks and the estimation of secure key rates, strengthening the overall security of the QKD system. We have rigorously characterized our source to estimate the mean photon number employing multiple detectors for comparison against measurements made with a single detector. Furthermore, we have also studied intensity fluctuations to help identify and mitigate any potential information leakage due to state preparation flaws. We aim to bridge the gap between theory and practice to achieve information-theoretic security.Comment: Comments and suggestions are welcome

    SEAMLESS EXPENSE SHARING FOR REMOTE PURCHASESā€

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    The present disclosure discloses payment processing that seamless expense sharing for remote purchases. When the user does not have plurality of physical card then the user may provide plurality of information associated with the card of the user. Based on the provided information QR code may be generated which may be also shared to family and friends via email or MMS. The generated QR code is provided to POS associated with the merchant. The merchant may send details to the third party for authorization based on which the details is sent to issuer for final authorization. Once the issuer approves, the link may be sent to user through which he/she may provide the approval for the payment. When the amount gets credited to the merchant, then the successful message may be sent to the user

    Quantum key distribution with multiphoton pulses: An advantage

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    In this article, we introduce a quantum key distribution protocol for the line of sight channels based on coincidence measurements. We present a proof-of-concept implementation of our protocol. We show that using coincidence measurements to monitor multi-photon pulses results in a higher secure key rate over longer distances for such channels. This key rate is higher than popular implementations of quantum key distribution protocol based on BB84, for example, the GLLP analysis [Quant. Info. Comput. \textbf{4}, 325 (2004)]. In the experiment, we could generate around 74%74 \% more key bits per signal pulse as compared to the GLLP analysis of BB84 protocol with similar parameters and equal value of mean photon number.Comment: 12 pages, 4 figures and 3 tables. Final accepted version (Accepted for publication in OSA Continuum

    Robotic intraoperative tracheal repair during retrosternal malignant goiter excision: an anesthetic challenge

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    Thyroidectomy is the treatment of choice for large retrosternal goiters. These tumors often are large enough to require thoracotomy. Robotic surgery can help in avoiding thoracotomy and its associated post operative complications. Rarely, such tumors and their surgery can be complicated by tracheal tears. Such tears, especially those near the carina are difficult to repair and often require open thoracotomy. We described such a case where we avoided open thoracotomy and instead performed a minimally invasive robotic repair of tracheal tear. The maintenance of ventilation during this robotic repair was critical. A combination of several airway devices was used to allow the complex surgical repair to be executed without affecting ventilation

    Ball valving laryngeal masses: a difficult ā€œballā€ in the anaesthetistsā€™ court

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    Dynamic airway obstruction (also called ball-valve effect) is a serious condition often seen in glottic lesions. This is an anesthetic challenge as total airway obstruction can occur after the induction of general anesthesia. We present a case of a middle aged female who had a large laryngeal mass which was showing ball-valve effect. The patient had refused for tracheostomy despite it being the safest procedure in the circumstances. We then performed videolaryngoscopy and managed to intubate the patient with the help of some improvisation. The patient underwent a succesful and uneventful surgery

    Examining the predictors of successful Airbnb bookings with Hurdle models: evidence from Europe, Australia, USA and Asia-Pacific cities

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    Recent studies on Airbnb have examined the predictors of room prices, successful reservations and customer satisfaction. However, a preliminary investigation of the listings from twenty-two cities across four continents revealed that a significant number of Airbnb homes remained non-booked. Thus, Poisson count-regression techniques cannot efficaciously explain the effects of predictors of successful Airbnb bookings. To address this gap, we proposed a text mining framework using Hurdle-based Poisson and Negative Binomial regressions. We found that the superhost status, host response time, and communication with guests emerged as the most significant predictors irrespective of geographies. We also found that the instant booking option strongly influences the bookings across cities with incoming business visitors. Additionally, we presented a machine learning-based variable-importance scheme, which helps determine the top predictors of successful bookings, to design customized recommendations for attracting more guests and unique advertisement content on P2P accommodation platforms
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