4,200 research outputs found

    MAGIC eyes to the extreme: testing the blazar emission models on EHBLs

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    Extreme high-energy peaked BL Lac objects (EHBLs) are blazars whose synchrotron emission peaks at exceptionally high energies, above few keV, in the hard X-ray regime. So far, only a handful of those objects has been detected at very high energy (VHE, E > 100 GeV) gamma rays by Imaging Atmospheric Cherenkov Telescopes. Very remarkably, VHE observations of some of these blazars (like 1ES 0229+200) have provided evidence of a VHE gamma-ray emission extending to several TeV, which is difficult to explain with standard, one-zone synchrotron self-Compton models usually applied to BL Lac objects. The MAGIC collaboration coordinated a multi-year, multi-wavelength observational campaign on ten targets. The MAGIC telescopes detected VHE gamma rays from four EHBLs. In this paper we focus on the source 1ES 1426+426 and its X-ray and VHE gamma-ray properties. The results of different models (synchrotron self-Compton, spine-layer, hadronic) reproducing the broadband spectral energy distribution are also presented.Comment: Proceedings of the 36th International Cosmic Ray Conference (ICRC2019), July 24th-August 1st, 2019. Madison, WI, U.S.

    Ambi√™ncia nas instala√ß√Ķes para produ√ß√£o de leite.

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    Este cap√≠tulo tem por finalidade apresentar as principais instala√ß√Ķes de um sistema de produ√ß√£o de leite destinado a animais em pastagem com suplementos aliment√≠cios e uso de insemina√ß√£o artificial. N√£o ser√£o apresentados detalhes estruturais das instala√ß√Ķes, j√° que o planejamento de constru√ß√Ķes rurais deve ser feito por t√©cnicos especializados com base nas caracter√≠sticas da propriedade e dos objetivos do produtor. No entanto, ser√£o listadas as principais instala√ß√Ķes para um sistema de produ√ß√£o de leite e ser√£o propostas algumas estrat√©gias para adequar a ambi√™ncia dessas instala√ß√Ķes, considerando o clima tropical √ļmido, que √© predominante na Regi√£o Amaz√īnica brasileira.bitstream/item/217361/1/cpafro-18462.pd

    Nonalcoholic Fatty Liver Disease Is Associated With Higher 1-year All-Cause Rehospitalization Rates in Patients Admitted for Acute Heart Failure

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    Repeat hospitalization due to acute heart failure (HF) is a global public health problem that markedly impacts on health resource use. Identifying novel predictors of rehospitalization would help physicians to determine the optimal postdischarge plan for preventing HF rehospitalization. Nonalcoholic fatty liver disease (NAFLD) is an emerging risk factor for many heart diseases, including HF. We assessed whether NAFLD at hospital admission predicts 1-year all-cause rehospitalization in patients with acute HF.We enrolled all patients consecutively admitted for acute HF to our General Medicine Division, from January 2013 to April 2014, after excluding patients with acute myocardial infarction, severe heart valve diseases, malignancy, known liver diseases, and those with volume overload related to extracardiac causes. NAFLD was diagnosed by ultrasonography and exclusion of competing etiologies. The primary outcome of the study was the 1-year all-cause rehospitalization rate.Among the 107 patients enrolled in the study, the cumulative rehospitalization rate was 12.1% at 1 month, 25.2% at 3 months, 29.9% at 6 months, and 38.3% at 1 year. Patients with NAFLD had markedly higher 1-year rehospitalization rates than those without NAFLD (58% vs 21% at 1 y; P\u200a<\u200a0.001 by the log-rank test). Cox regression analysis revealed that NAFLD was associated with a 5.5-fold increased risk of rehospitalization (adjusted hazard ratio 5.56, 95% confidence interval 2.46-12.1, P\u200a<\u200a0.001) after adjustment for multiple HF risk factors and potential confounders.In conclusion, NAFLD was independently associated with higher 1-year rehospitalization in patients hospitalized for acute HF

    Nonalcoholic fatty liver disease and increased risk of 1-year all-cause and cardiac hospital readmissions in elderly patients admitted for acute heart failure

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    Nonalcoholic fatty liver disease (NAFLD) is an emerging risk factor for heart failure (HF). Although some progress has been made in improving survival among patients admitted for HF, the rates of hospital readmissions and the related costs continue to rise dramatically. We sought to examine whether NAFLD and its severity (diagnosed at hospital admission) was independently associated with a higher risk of 1-year all-cause and cardiac re-hospitalization in patients admitted for acute HF. We studied 212 elderly patients who were consecutively admitted with acute HF to the Hospital of Negrar (Verona) over a 1-year period. Diagnosis of NAFLD was based on ultrasonography, whereas the severity of advanced NAFLD fibrosis was based on the fibrosis (FIB)-4 score and other non-invasive fibrosis scores. Patients with acute myocardial infarction, severe valvular heart diseases, endstage renal disease, cancer, known liver diseases or decompensated cirrhosis were excluded. Cox regression was used to estimate hazard ratios (HR) for the associations between NAFLD and the outcome(s) of interest. The cumulative rate of 1-year all-cause re-hospitalizations was 46.7% (n = 99, mainly due to cardiac causes). Patients with NAFLD (n = 109; 51.4%) had remarkably higher 1-year all-cause and cardiac re-hospitalization rates compared with their counterparts without NAFLD. Both event rates were particularly increased in those with advanced NAFLD fibrosis. NAFLD was associated with a 5-fold increased risk of 1-year all-cause re-hospitalization (adjusted-hazard ratio 5.05, 95% confidence intervals 2.78-9.10, p<0.0001) after adjustment for established risk factors and potential confounders. Similar results were found for 1-year cardiac re-hospitalization (adjusted-hazard ratio 8.05, 95% confidence intervals 3.77-15.8, p<0.0001). In conclusion, NAFLD and its severity were strongly and independently associated with an increased risk of 1-year all-cause and cardiac re-hospitalization in elderly patients admitted with acute HF

    The quassinoid derivative NBT-272 targets both the AKT and ERK signaling pathways in embryonal tumors

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    The quassinoid analogue NBT-272 has been reported to inhibit MYC, thus warranting a further effort to better understand its preclinical properties in models of embryonal tumors (ET), a family of childhood malignancies sharing relevant biological and genetic features such as deregulated expression of MYC oncogenes. In our study, NBT-272 displayed a strong anti-proliferative activity in vitro that resulted from the combination of diverse biological effects, ranging from G1/S arrest of the cell cycle to apoptosis and autophagy. The compound prevented the full activation of both the eukaryotic initiation factor 4E (eIF4E) and its binding protein 4EBP-1, regulating cap-dependent protein translation. Interestingly, all responses induced by NBT-272 in ET could be attributed to interference with two main pro-proliferative signaling pathways, i.e. the AKT and the MEK/extracellular signal-regulated kinase (ERK) pathways. These findings also suggested that the depleting effect of NBT-272 on MYC protein expression occurred via indirect mechanisms, rather than selective inhibition. Finally, the ability of NBT-272 to arrest tumor growth in a xenograft model of neuroblastoma plays a role in the strong anti-tumor activity of this compound, both in vitro and in vivo, with its potential to target cell-survival pathways that are relevant for the development and progression of ET

    Detection of very high energy gamma-ray emission from the gravitationally-lensed blazar QSO B0218+357 with the MAGIC telescopes

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    Context. QSO B0218+357 is a gravitationally lensed blazar located at a redshift of 0.944. The gravitational lensing splits the emitted radiation into two components, spatially indistinguishable by gamma-ray instruments, but separated by a 10-12 day delay. In July 2014, QSO B0218+357 experienced a violent flare observed by the Fermi-LAT and followed by the MAGIC telescopes. Aims. The spectral energy distribution of QSO B0218+357 can give information on the energetics of z ~ 1 very high energy gamma- ray sources. Moreover the gamma-ray emission can also be used as a probe of the extragalactic background light at z ~ 1. Methods. MAGIC performed observations of QSO B0218+357 during the expected arrival time of the delayed component of the emission. The MAGIC and Fermi-LAT observations were accompanied by quasi-simultaneous optical data from the KVA telescope and X-ray observations by Swift-XRT. We construct a multiwavelength spectral energy distribution of QSO B0218+357 and use it to model the source. The GeV and sub-TeV data, obtained by Fermi-LAT and MAGIC, are used to set constraints on the extragalactic background light. Results. Very high energy gamma-ray emission was detected from the direction of QSO B0218+357 by the MAGIC telescopes during the expected time of arrival of the trailing component of the flare, making it the farthest very high energy gamma-ray sources detected to date. The observed emission spans the energy range from 65 to 175 GeV. The combined MAGIC and Fermi-LAT spectral energy distribution of QSO B0218+357 is consistent with current extragalactic background light models. The broad band emission can be modeled in the framework of a two zone external Compton scenario, where the GeV emission comes from an emission region in the jet, located outside the broad line region.Comment: 11 pages, 6 figures, accepted for publication in A&

    A search for spectral hysteresis and energy-dependent time lags from X-ray and TeV gamma-ray observations of Mrk 421

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    Blazars are variable emitters across all wavelengths over a wide range of timescales, from months down to minutes. It is therefore essential to observe blazars simultaneously at different wavelengths, especially in the X-ray and gamma-ray bands, where the broadband spectral energy distributions usually peak. In this work, we report on three "target-of-opportunity" (ToO) observations of Mrk 421, one of the brightest TeV blazars, triggered by a strong flaring event at TeV energies in 2014. These observations feature long, continuous, and simultaneous exposures with XMM-Newton (covering X-ray and optical/ultraviolet bands) and VERITAS (covering TeV gamma-ray band), along with contemporaneous observations from other gamma-ray facilities (MAGIC and Fermi-LAT) and a number of radio and optical facilities. Although neither rapid flares nor significant X-ray/TeV correlation are detected, these observations reveal subtle changes in the X-ray spectrum of the source over the course of a few days. We search the simultaneous X-ray and TeV data for spectral hysteresis patterns and time delays, which could provide insight into the emission mechanisms and the source properties (e.g. the radius of the emitting region, the strength of the magnetic field, and related timescales). The observed broadband spectra are consistent with a one-zone synchrotron self-Compton model. We find that the power spectral density distribution at ‚Č≥4√ó10‚ąí4\gtrsim 4\times 10^{-4} Hz from the X-ray data can be described by a power-law model with an index value between 1.2 and 1.8, and do not find evidence for a steepening of the power spectral index (often associated with a characteristic length scale) compared to the previously reported values at lower frequencies.Comment: 45 pages, 15 figure

    Republication: Targeting PI3KC2ő≤ Impairs Proliferation and Survival in Acute Leukemia, Brain Tumours and Neuroendocrine Tumours

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    BACKGROUND Eight human catalytic phosphoinositide 3-kinase (PI3K) isoforms exist which are subdivided into three classes. While class I isoforms have been well-studied in cancer, little is known about the functions of class II PI3Ks. MATERIALS AND METHODS The expression pattern and functions of the class II PI3KC2ő≤ isoform were investigated in a panel of tumour samples and cell lines. RESULTS Overexpression of PI3KC2ő≤ was found in subsets of tumours and cell lines from acute myeloid leukemia (AML), glioblastoma multiforme (GBM), medulloblastoma (MB), neuroblastoma (NB), and small cell lung cancer (SCLC). Specific pharmacological inhibitors of PI3KC2ő≤ or RNA interference impaired proliferation of a panel of human cancer cell lines and primary cultures. Inhibition of PI3KC2ő≤ also induced apoptosis and sensitised the cancer cells to chemotherapeutic agents. CONCLUSION Together, these data show that PI3KC2ő≤ contributes to proliferation and survival in AML, brain tumours and neuroendocrine tumours, and may represent a novel target in these malignancies
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