2,809 research outputs found

    Records Of The Late Glacial Influx Of Ice-Rafted Detritus On The Orphan Knoll, Northwest Atlantic Ocean

    Get PDF
    The top 110 centimeters of IRD records for GVY002 reveal 5 distinct peaks in IRD input, each between 4000-6500 lithics/gram. Three of these peaks coincide with three peaks in the Ca/Sr ratios in the upper meter indicative of dolomite rich IRD from the Canadian margin. The IRD record and Ca/Sr ratio record generated in this study, when compared to the previously generated similar records in GVY001, reveals a similar pattern but over a much longer downcore sediment interval (over the upper 4.5 meters in GVY001 versus the upper 1.8 meters in GVY002). This is due to the higher sedimentation rate in GVY001. Hendry, et al. (2019) tentatively correlated the shallowest peaks in Ca/Sr ratios with Heinrich Events H0 - H4 by correlating the Ca/Sr ratio records in GVY001 to the δ18O record of N. pachyderma (s.). An IRD peak in GVY001 corresponds to each of the Heinrich Events identified in Hendry, et al. (2019). Subsequent comparison of GVY002 IRD records with those of GVY001 suggest that Heinrich Events H0, H1, and H2 can be identified over the first meter. Both GVY002 and GVY001 display two additional IRD peaks of at least 4000 lithics/gram between H1 and H2 during intervals of very low Ca/Sr ratios

    I servizi Internet: varietà o caos?

    Get PDF
    Dopo solo pochi anni dall'apparire di Internet sulla scena mondiale, e soprattutto nazionale, si è visto incrementare notevolmente sia il numero di servizi disponibili che la loro qualità. Ultimamente si è notato l'appiattimento dell'offerta su di un solo servizio che li possa inglobare tutti, il WWW, fornendo una interfaccia unica ai più variegati strumenti ed alle più sfrenate manifestazioni della genialità, creativa ed imprenditoriale, della mente umana. Tutto ciò porterà ad un 'caos' primordiale, od al 'villaggio globale' dove tutti potranno usufruire delle gioie della tecnologia senza esserne fagocitati

    Undiagnosed vertebral fractures influence quality of life in postmenopausal women with reduced ultrasound parameters.

    Get PDF
    Osteoporosis, a multifactorial systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue leading to increased bone fragility, is a worldwide public health problem. Vertebral fractures affect approximately 20% of postmenopausal women and are a hallmark of osteoporosis, but they may pass unnoticed, although they may lead to long-term immobility and disability. The aims of the present study were (1) to determine the prevalence and the severity of vertebral fractures in a large cohort of Italian women aged 60 years or older with reduced values of quantitative ultrasound parameters; and (2) to assess whether vertebral fractures and other variables may be associated with health-related quality of life. A total of 2450 women without back pain aged 60 years or older, after the completion of the Quality of Life Questionnaire of the European Foundation for Osteoporosis QUALEFFO, underwent quantitative ultrasound evaluation of the calcaneus; in those with a stiffness t-score of a parts per thousand currency sign -2 (n = 1194), radiographic evaluation of the thoracic and lumbar spine was carried out and then quantitative morphometry was performed by dedicated software (MorphoXpress). The radiographic analysis was carried out on 885 women who presented films of adequate quality. Multivariate regression was used to adjust for confounding variables. Of those who underwent radiographic analysis, 681 had no vertebral fractures, and 204 women (23.1%) had one or more previously undiagnosed vertebral fractures. The prevalence of previously undiagnosed vertebral fractures increased with advancing age with more than 30% of women older than 75 years having at least one fracture. Older age, body mass index, and severe vertebral fractures were independently associated with a worse total QUALEFFO score. We found that approximately one in four women showed evidence of undiagnosed vertebral fractures, and there was a strong age effect trend. Moreover, the severity grade of vertebral fractures, more than the number of fractures, was associated with a worsening of health-related quality of life as assessed by QUALEFFO. These findings confirm the clinical relevance of an early diagnosis of vertebral fractures and seem to support the usefulness of quantitative ultrasound measurements in the stratification of postmenopausal women at increased fracture risk

    Efficiency of an Air Cleaner Device in Reducing Aerosol Particulate Matter (PM) in Indoor Environments

    Get PDF
    Abstract: Indoor air quality (IAQ) in household environments is mandatory since people spend most of their time in indoor environments. In order to guarantee a healthy environment, air purification devices are often employed. In the present work, a commercial household vacuum cleaner has been tested in order to verify its eciency in reducing the mass concentration and particle number of aerosol particulate matter (PM). The eciency has been tested measuring, while the instrument was working, PM10 (particles with aerodynamic diameter less than 10 m), PM2.5 (particles with aerodynamic diameter less than 2.5 m), PM1 (particles with aerodynamic diameter less than 1 m), and 7 size-fractions in the range between 0.3 and >10 m. Measurements have been carried out by means of a portable optical particle counter instrument and simulating the working conditions typical of a household environment. It has been found that the tested commercial device significantly reduces both PM concentrations and particle number, especially in the finest fraction, i.e., particles in the range 0.3\u20130.5 m, allowing an improvement of indoor air quality

    Electromagnetic signals produced by elastic waves in the Earth’s crust

    Get PDF
    The paper describes the excitation of geoelectromagnetic-field oscillations caused by elastic waves propagating in the Earth’s crust and generated by natural and anthropogenic phenomena, such as earthquakes, explosions, etc. Two mechanisms of electromagnetic signal generation, i.e. induction and electrokinetics ones, are considered and a comparative analysis between them is carried out. The first mechanism is associated with the induction of Foucault currents due to movements of the Earth’s crust in the core geomagnetic field. The second mechanism is connected with movements of liquids filling pores and cracks of rocks. An equation is derived for describing in a uniform way these two manifestations of seismomagnetism. The equation is solved for body and surface waves. The study shows that a magnetic precursor signal is moving in the front of elastic waves

    MiniBooNE

    Full text link
    The physics motivations, design, and status of the Booster Neutrino Experiment at Fermilab, MiniBooNE, are briefly discussed. Particular emphasis is given on the ongoing preparatory work that is needed for the MiniBooNE muon neutrino to electron neutrino oscillation appearance search. This search aims to confirm or refute in a definitive and independent way the evidence for neutrino oscillations reported by the LSND experiment.Comment: 3 pages, no figures, to appear in the proceedings of the 9th International Conference on Astroparticle and Underground Physics (TAUP 2005), Zaragoza, Spain, 10-14 Sep 200
    • …
    corecore