149 research outputs found

    Baryon Number Violation Involving Higher Generations

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    Proton stability seems to constrain rather strongly any baryon number violating process. We investigate the possibility of baryon number violating processes involving right-handed dynamics or higher generation quarks. Our results strongly suggest that there will be no possibility to observe baryon number violation in tau or higher generation quark decays, at any future machine.Comment: Improved figures, small changes in the text, added reference. To appear in Phys. Rev.

    LEOSTAR: A Small Spacecraft for LEO Communication Missions

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    This paper outlines the major features of LEOSTAR, a small spacecraft able to support two way data message communications and position reporting missions with a multisatellite constellation. LEOSTAR is a three-axis gravity gradient stabilized satellite. A semi-passive control concept is envisaged with an extensible boom providing attitude stabilization together with three orthogonal Magnetic Torquers, an on-board dedicated computer and other devices. Thrusters provide the station keeping and transfer maneuvers according to an optimized strategy. A bipropellant system with monomethyhl hydrazine as propellant and nitrogen tetroxide as oxidizer is adopted. Large autonomy is envisaged through the adoption of an onboard system management processor. The communications\u27 payload power/mass range from 100 W/40 Kg to 200 W/60 Kg. A payload volume of 0.12 m3 and a maximum antenna dimension of 1 m. are allowed. LEOSTAR is designed to be compatible both with SCOUT and PEGASUS launchers in single or double launch configurations. It can also be launched by large vehicles such ARIANE 4 and Delta in cluster and/or piggy back modes

    Solvent-Free Synthesis of Quaternary Oxazolidine-2-thione β3-Amino Ester Analogs

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    A solvent-free organocatalyzed intermolecular cyclization reaction starting from β-substituted γ-hydroxy-α,β-unsaturated esters and aryl isothiocyanates proceeds via an aza-Michael addition to provide previously unknown quaternary oxazolidine-2-thione β3 amino ester analogs. A panel of diversely-substituted esters was investigated, including β,γ-disubstituted examples which provided the target molecules with very high cis diastereoselectivity

    Risk perception and ethnic background in construction workers: Results of a cross-sectional study in a group of trainees of a vocational school in italy

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    Risk perception can be influenced by cultural background. The study aims to evaluate risk perception, considering different ethnicities of construction workers from vocational schools in Italy. We administered a questionnaire investigating four different dimensions: Perceived behavioral control (PBC), Danger perception (DP), Safety climate (SC), and Attitude towards safe actions (ATSA). 562 workers answered: 72.4% from Italy, 14.2% from eastern Europe, 9.4% from Balkans, and 3.9% from North Africa. The participants indicated quite low control, attributable to the haste in performing the job. The workers perceived their specific job tasks as riskier compared to the tasks of their colleagues. They reported as fundamental the respecting of safety rules, but indicating that supervisors do not adequately promote safety behaviors. Finally, construction workers judged as \u201cbrave\u201d the colleagues working without protective equipment. When compared to Italians, North Africa workers showed a lower perception of the possibility to control their safe behaviors (p = 0.040), while both eastern Europeans and Balkan obtained higher scores at the ATSA dimension, indicating a kind of fatalistic acceptance of the risky situations at work. Eastern Europeans also showed a lower perception of the dangers (p = 0.002), while Balkan demonstrated a perception of SC even better than the Italian group (p = 0.005)

    Spastin recovery in hereditary spastic paraplegia by preventing neddylation-dependent degradation

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    Hereditary Spastic Paraplegia (HSP) is a neurodegenerative disease most commonly caused by autosomal dominant mutations in the SPG4 gene encoding the microtubule-severing protein spastin. We hypothesise that SPG4-HSP is attributable to reduced spastin function because of haploinsufficiency; thus, therapeutic approaches which elevate levels of the wild-type spastin allele may be an effective therapy. However, until now, how spastin levels are regulated is largely unknown. Here, we show that the kinase HIPK2 regulates spastin protein levels in proliferating cells, in differentiated neurons and in vivo. Our work reveals that HIPK2-mediated phosphorylation of spastin at S268 inhibits spastin K48-poly-ubiquitination at K554 and prevents its neddylation-dependent proteasomal degradation. In a spastin RNAi neuronal cell model, overexpression of HIPK2, or inhibition of neddylation, restores spastin levels and rescues neurite defects. Notably, we demonstrate that spastin levels can be restored pharmacologically by inhibiting its neddylation-mediated degradation in neurons derived from a spastin mouse model of HSP and in patient-derived cells, thus revealing novel therapeutic targets for the treatment of SPG4-HSP

    Association between red cell distribution width and response to methotrexate in rheumatoid arthritis

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    Red cell distribution width (RDW) is an unconventional biomarker of inflammation. We aimed to explore its role as a predictor of treatment response in rheumatoid arthritis (RA). Eighty-two RA patients (55 females), median age [interquartile range] 63 years [52-69], were selected by scanning the medical records of a rheumatology clinic, to analyze the associations between baseline RDW, disease activity scores and inflammatory markers, as well as the relationship between RDW changes following methotrexate (MTX) and treatment response. The lower the median baseline RDW, the greater were the chances of a positive EULAR response at three months, 13.5% [13.0-14.4] being among those with good response, vs 14.0% [13.2-14.7] and 14.2% [13.5- 16.0] (p=0.009) among those with moderate and poor response, respectively. MTX treatment was followed by a significant RDW increase (p<0.0001). The increase of RDW was greater among patients with good EULAR response, becoming progressively smaller in cases with moderate and poor response (1.0% [0.4-1.4] vs. 0.7 [0.1-2.0] vs. 0.3 [-0.1-0.8]; p=0.03). RDW is a strong predictor of early response to MTX in RA. RDW significantly increases after MTX initiation in parallel to treatment response, suggesting a role as a marker of MTX effectiveness

    Volcanic Risk Management: the Case of Mt. Etna 2006 Eruption

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    Mt. Etna volcano is located in a very populated area of eastern Sicily (Italy). Its permanent degassing activity from summit craters and frequent eruptions impact significantly on town habitations and cultivated areas. In the latest years Etna has produced copious ash emission causing great losses to local economy and causing serious hazards to national and international air traffic over Mediterranean area and the often closure of Catania airport. In July 2006 eruptive vents opened on the East and South flanks of the summit craters showing irregular explosive and effusive activity lasting 6 months. This eruption represented the opportunity to perform the pre-operative test of FP6 Eurorisk-Preview (Prevention, Information and Early Warning) project aimed to develop tools for monitoring volcanoes. The test was performed during two temporal phases: the first one of early-warning was aimed to measure ground deformation and the second one during the crisis to survey volcanic ash produced during the explosions. The ground deformations were measured through the elaboration of SAR data. Beside the geophysical objectives, the test was also important to check data availability and efficiency of European Space Agency procedures. The pre-operative test has been peculiar to understand and quantify the delivering time of the final satellite products expected from the Volcanological Observatory in operative case. The analysis of July 2005 - July 2006 SAR data showed a pre-eruptive inflation trend in agreement with the ground network of GPS data. The magmatic source, that produced the September - October activity, has been located about 2.7 km below the summit craters. During the crisis phase characterized by paroxysmal activity, the Italian Civil Protection (DPC) in charge of airport closure in case of volcanic hazard, requested the satellite volcanic ash product retrieved from the NASA-MODIS data. An agreement between the industry Telespazio as direct broadcast of satellite data at Matera station and INGV was signed in order to elaborate the data in near-real time. The volcanic ash product provided information about: the presence of volcanic ash in the air; the affected area; the volcanic plume dispersal direction, dimensions and altitude and the volcanic ash loading. The satellite products and the observations report have been successively inserted in a web-interface. At the same time the observations report has been linked to the DPC dedicated Web-GIS interface that allows in a short time the availability of volcanic ash information to DPC in support to their decisions.Published77-811.10. TTC - Telerilevamentoope

    Volcanic Risk Management: the Case of Mt. Etna 2006 Eruption

    Get PDF
    Mt. Etna volcano is located in a very populated area of eastern Sicily (Italy). Its permanent degassing activity from summit craters and frequent eruptions impact significantly on town habitations and cultivated areas. In the latest years Etna has produced copious ash emission causing great losses to local economy and causing serious hazards to national and international air traffic over Mediterranean area and the often closure of Catania airport. In July 2006 eruptive vents opened on the East and South flanks of the summit craters showing irregular explosive and effusive activity lasting 6 months. This eruption represented the opportunity to perform the pre-operative test of FP6 Eurorisk-Preview (Prevention, Information and Early Warning) project aimed to develop tools for monitoring volcanoes. The test was performed during two temporal phases: the first one of early-warning was aimed to measure ground deformation and the second one during the crisis to survey volcanic ash produced during the explosions. The ground deformations were measured through the elaboration of SAR data. Beside the geophysical objectives, the test was also important to check data availability and efficiency of European Space Agency procedures. The pre-operative test has been peculiar to understand and quantify the delivering time of the final satellite products expected from the Volcanological Observatory in operative case. The analysis of July 2005 - July 2006 SAR data showed a pre-eruptive inflation trend in agreement with the ground network of GPS data. The magmatic source, that produced the September - October activity, has been located about 2.7 km below the summit craters. During the crisis phase characterized by paroxysmal activity, the Italian Civil Protection (DPC) in charge of airport closure in case of volcanic hazard, requested the satellite volcanic ash product retrieved from the NASA-MODIS data. An agreement between the industry Telespazio as direct broadcast of satellite data at Matera station and INGV was signed in order to elaborate the data in near-real time. The volcanic ash product provided information about: the presence of volcanic ash in the air; the affected area; the volcanic plume dispersal direction, dimensions and altitude and the volcanic ash loading. The satellite products and the observations report have been successively inserted in a web-interface. At the same time the observations report has been linked to the DPC dedicated Web-GIS interface that allows in a short time the availability of volcanic ash information to DPC in support to their decisions
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