707 research outputs found

    Observation of the TeV gamma-ray source MGRO J1908+06 with ARGO-YBJ

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    The extended gamma ray source MGRO J1908+06, discovered by the Milagro air shower detector in 2007, has been observed for about 4 years by the ARGO-YBJ experiment at TeV energies, with a statistical significance of 6.2 standard deviations. The peak of the signal is found at a position consistent with the pulsar PSR J1907+0602. Parametrizing the source shape with a two-dimensional Gauss function we estimate an extension \sigma = 0.49 \pm 0.22 degrees, consistent with a previous measurement by the Cherenkov Array H.E.S.S.. The observed energy spectrum is dN/dE = 6.1 \pm 1.4 \times 10^-13 (E/4 TeV)^{-2.54 \pm 0.36} photons cm^-2 s^-1 TeV^-1, in the energy range 1-20 TeV. The measured gamma ray flux is consistent with the results of the Milagro detector, but is 2-3 times larger than the flux previously derived by H.E.S.S. at energies of a few TeV. The continuity of the Milagro and ARGO-YBJ observations and the stable excess rate observed by ARGO-YBJ along 4 years of data taking support the identification of MGRO J1908+06 as the steady powerful TeV pulsar wind nebula of PSR J1907+0602, with an integrated luminosity above 1 TeV about 1.8 times the Crab Nebula luminosity.Comment: 6 pages, accepted for pubblication by ApJ. Replaced to correct the author lis

    Pre-referral Rectal Artesunate Treatment by Community-Based Treatment Providers in Ghana, Guinea-Bissau, Tanzania, and Uganda (Study 18): A Cluster-Randomized Trial

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    BACKGROUND:  If malaria patients who cannot be treated orally are several hours from facilities for injections, rectal artesunate prior to hospital referral can prevent death and disability. The goal is to reduce death from malaria by having rectal artesunate treatment available and used. How best to do this remains unknown. METHODS:  Villages remote from a health facility were randomized to different community-based treatment providers trained to provide rectal artesunate in Ghana, Guinea-Bissau, Tanzania, and Uganda. Prereferral rectal artesunate treatment was provided in 272 villages: 109 through community-based health workers (CHWs), 112 via trained mothers (MUMs), 25 via trained traditional healers (THs), and 26 through trained community-chosen personnel (COMs); episodes eligible for rectal artesunate were established through regular household surveys of febrile illnesses recording symptoms eligible for prereferral treatment. Differences in treatment coverage with rectal artesunate in children aged <5 years in MUM vs CHW (standard-of-care) villages were assessed using the odds ratio (OR); the predictive probability of treatment was derived from a logistic regression analysis, adjusting for heterogeneity between clusters (villages) using random effects. RESULTS:  Over 19 months, 54 013 children had 102 504 febrile episodes, of which 32% (31 817 episodes) had symptoms eligible for prereferral therapy; 14% (4460) children received treatment. Episodes with altered consciousness, coma, or convulsions constituted 36.6% of all episodes in treated children. The overall OR of treatment between MUM vs CHW villages, adjusting for country, was 1.84 (95% confidence interval [CI], 1.20-2.83; P = .005). Adjusting for heterogeneity, this translated into a 1.67 higher average probability of a child being treated in MUM vs CHW villages. Referral compliance was 81% and significantly higher with CHWs vs MUMs: 87% vs 82% (risk ratio [RR], 1.1 [95% CI, 1.0-1.1]; P < .0001). There were more deaths in the TH cluster than elsewhere (RR, 2.7 [95% CI, 1.4-5.6]; P = .0040). CONCLUSIONS:  Prereferral episodes were almost one-third of all febrile episodes. More than one-third of patients treated had convulsions, altered consciousness, or coma. Mothers were effective in treating patients, and achieved higher coverage than other providers. Treatment access was low. CLINICAL TRIALS REGISTRATION:  ISRCTN58046240

    Identification of the TeV Gamma-ray Source ARGO J2031+4157 with the Cygnus Cocoon

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    The extended TeV gamma-ray source ARGO J2031+4157 (or MGRO J2031+41) is positionally consistent with the Cygnus Cocoon discovered by FermiFermi-LAT at GeV energies in the Cygnus superbubble. Reanalyzing the ARGO-YBJ data collected from November 2007 to January 2013, the angular extension and energy spectrum of ARGO J2031+4157 are evaluated. After subtracting the contribution of the overlapping TeV sources, the ARGO-YBJ excess map is fitted with a two-dimensional Gaussian function in a square region of 10×1010^{\circ}\times 10^{\circ}, finding a source extension σext\sigma_{ext}= 1^{\circ}.8±\pm0^{\circ}.5. The observed differential energy spectrum is dN/dE=(2.5±0.4)×1011(E/1TeV)2.6±0.3dN/dE =(2.5\pm0.4) \times 10^{-11}(E/1 TeV)^{-2.6\pm0.3} photons cm2^{-2} s1^{-1} TeV1^{-1}, in the energy range 0.2-10 TeV. The angular extension is consistent with that of the Cygnus Cocoon as measured by FermiFermi-LAT, and the spectrum also shows a good connection with the one measured in the 1-100 GeV energy range. These features suggest to identify ARGO J2031+4157 as the counterpart of the Cygnus Cocoon at TeV energies. The Cygnus Cocoon, located in the star-forming region of Cygnus X, is interpreted as a cocoon of freshly accelerated cosmic rays related to the Cygnus superbubble. The spectral similarity with Supernova Remnants indicates that the particle acceleration inside a superbubble is similar to that in a SNR. The spectral measurements from 1 GeV to 10 TeV allows for the first time to determine the possible spectrum slope of the underlying particle distribution. A hadronic model is adopted to explain the spectral energy distribution.Comment: 16 pages, 3 figures, has been accepted by ApJ for publicatio

    Weak Sequential Composition in Process Algebras

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    n this paper we study a special operator for sequential composition, which is defined relative to a dependency relation over the actions of a given system. The idea is that actions which are not dependent (intuitively because they share no common resources) do not have to wait for one another to proceed, even if they are composed sequentially. Such a notion has been studied before in a linear-time setting, but until recently there has been no systematic investigation in the context of process algebras. We give a structural operational semantics for a process algebraic language containing such a sequential composition operator, which shows some interesting interplay with choice. We give a complete axiomatisation of strong bisimilarity and we show consistency of the operational semantics with an event-based denotational semantics developed recently by the second author. The axiom system allows to derive the communication closed layers law, which in the linear time setting has been shown to be a very useful instrument in correctness preserving transformations. We conclude with a couple of examples

    End-to-end equalization with convolutional neural networks

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    This work aims to implement a novel deep learning architecture to perform audio processing in the context of matched equalization. Most existing methods for automatic and matched equalization show effective performance and their goal is to find a respective transfer function given a frequency response. Neverthe-less, these procedures require a prior knowledge of the type offilters to be modeled. In addition, fixed filter bank architecturesare required in automatic mixing contexts. Based on end-to-endconvolutional neural networks, we introduce a general purpose ar-chitecture for equalization matching. Thus, by using an end-to-end learning approach, the model approximates the equalizationtarget as a content-based transformation without directly findingthe transfer function. The network learns how to process the au-dio directly in order to match the equalized target audio. We trainthe network through unsupervised and supervised learning proce-dures. We analyze what the model is actually learning and howthe given task is accomplished. We show the model performing matched equalization forshelving, peaking, lowpass and highpass IIR and FIR equalizers

    AMPA receptor GluA2 subunit defects are a cause of neurodevelopmental disorders.

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    AMPA receptors (AMPARs) are tetrameric ligand-gated channels made up of combinations of GluA1-4 subunits encoded by GRIA1-4 genes. GluA2 has an especially important role because, following post-transcriptional editing at the Q607 site, it renders heteromultimeric AMPARs Ca2+-impermeable, with a linear relationship between current and trans-membrane voltage. Here, we report heterozygous de novo GRIA2 mutations in 28 unrelated patients with intellectual disability (ID) and neurodevelopmental abnormalities including autism spectrum disorder (ASD), Rett syndrome-like features, and seizures or developmental epileptic encephalopathy (DEE). In functional expression studies, mutations lead to a decrease in agonist-evoked current mediated by mutant subunits compared to wild-type channels. When GluA2 subunits are co-expressed with GluA1, most GRIA2 mutations cause a decreased current amplitude and some also affect voltage rectification. Our results show that de-novo variants in GRIA2 can cause neurodevelopmental disorders, complementing evidence that other genetic causes of ID, ASD and DEE also disrupt glutamatergic synaptic transmission

    A Randomized Phase II Trial of Epigenetic Priming with Guadecitabine and Carboplatin in Platinum-resistant, Recurrent Ovarian Cancer

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    © 2020 American Association for Cancer Research Inc.. All rights reserved. Purpose: Platinum resistance in ovarian cancer is associated with epigenetic modifications. Hypomethylating agents (HMA) have been studied as carboplatin resensitizing agents in ovarian cancer. This randomized phase II trial compared guadecitabine, a second-generation HMA, and carboplatin (GþC) against second-line chemotherapy in women with measurable or detectable platinum-resistant ovarian cancer. Patients and Methods: Patients received either GþC (guadecitabine 30 mg/m2 s.c. once-daily for 5 days and carboplatin) or treatment of choice (TC; topotecan, pegylated liposomal doxorubicin, paclitaxel, or gemcitabine) in 28-day cycles until progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS); secondary endpoints were RECIST v1.1 and CA-125 response rate, 6-month PFS, and overall survival (OS). Results: Of 100 patients treated, 51 received GþC and 49 received TC, of which 27 crossed over to GþC. The study did not meet its primary endpoint as the median PFS was not statistically different between arms (16.3 weeks vs. 9.1 weeks in the GþC and TC groups, respectively; P ¼ 0.07). However, the 6-month PFS rate was significantly higher in the GþC group (37% vs. 11% in TC group; P ¼ 0.003). The incidence of grade 3 or higher toxicity was similar in GþC and TC groups (51% and 49%, respectively), with neutropenia and leukopenia being more frequent in the GþC group. Conclusions: Although this trial did not show superiority for PFS of GþC versus TC, the 6-month PFS increased in GþC treated patients. Further refinement of this strategy should focus on identification of predictive markers for patient selection
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