1,670 research outputs found

    The PADME experiment at LNF

    Get PDF
    Massive photon-like particles are predicted in many extensions of the Standard Model. They have interactions similar to the photon, are vector bosons, and can be produced together with photons. The PADME experiment proposes a search for the dark photon (AA') in the e+eγAe^+e^- \to \gamma A' process in a positron-on-target experiment, exploiting the positron beam of the DAΦ\PhiNE linac at the Laboratori Nazionali di Frascati, INFN. In one year of running a sensitivity in the relative interaction strength down to 10610^{-6} is achievable, in the mass region from 2.5 MeV <MA<<M_{A'}< 22.5 MeV. The proposed experimental setup and the analysis technique is discussed.Comment: to be published in the DHF2014 proceedings EPJ Web of Conference

    Coronary age as a risk factor in the modified Framingham risk score

    Get PDF
    BACKGROUND: Clinical guidelines emphasize risk assessment as vital to patient selection for medical primary intervention. However, risk assessment methods are restricted in their ability to predict further coronary events. The most widely accepted tool in the United States is the Framingham risk score. In these equations age is a powerful risk factor. Although the extent of coronary atherosclerosis increases with age, there is large inter-individual variability in the rate of development and progression of this disease. This fact limits the utility of Framingham scoring when applied to individuals. Electron beam tomography (EBT), which measures coronary calcium, provides a non-invasive method for assessing coronary plaque burden, thus offering the possibility of providing a more accurate estimate of an individual's "arterial age" than from chronological age alone. METHODS: In this paper we discuss a new and simple method for incorporating the coronary calcium score (CCS) to modify the Framingham Risk Assessment (FRA). Using this method, a coronary artery calcium (CAC) age equivalent is generated that replaces chronological age in Framingham scoring. RESULTS AND DISCUSSION: Using a percentile table of CCS scores by age group and sex, individuals are matched to the age group whose calcium score most closely approximates their own individual score. The original 10-year absolute risk score of a 65-year old man with a CCS of 6 based on chronological age is 10%, whereas the modified absolute risk score based on CAC age equivalents is 2%. CONCLUSION: Our approach of replacing chronological age with CAC age equivalents in the Framingham equations possesses simplicity of application combined with precision. Physicians can easily derive adjusted Framingham risk scores and prescribe intervention methods based on patients' ten-year risks. The adjusted ten-year risks are likely to be more accurate than unadjusted risks since they are based on coronary calcium score information. The modified FRA approach not only may increase the predicted risk for some patients, but also may decrease the predicted risk for others, making it a more precise adjustment than other methods

    GEANT4-based full simulation of the PADME experiment at the DAΦNE BTF

    Get PDF
    A possible solution to the dark matter problem postulates that dark particles can interact with Standard Model particles only through a new force mediated by a “portal”. If the new force has a U(1) gauge structure, the “portal” is a massive photon-like vector particle, called dark photon or A′. The PADME experiment at the DAΦNE Beam-Test Facility (BTF) in Frascati is designed to detect dark photons produced in positron on fixed target annihilations decaying to dark matter (e+e-→γA′) by measuring the final state missing mass. The experiment will be composed of a thin active diamond target where a 550 MeV positron beam will impinge to produce e+e- annihilation events. The surviving beam will be deflected with a magnet while the photons produced in the annihilation will be measured by a calorimeter composed of BGO crystals. To reject the background from Bremsstrahlung gamma production, a set of segmented plastic scintillator vetoes will be used to detect positrons exiting the target with an energy lower than that of the beam, while a fast small angle calorimeter will be used to reject the e+e-→γγ(γ) background. To optimize the experimental layout in terms of signal acceptance and background rejection, the full layout of the experiment was modelled with the GEANT4 simulation package. In this paper we will describe the details of the simulation and report on the results obtained with the software

    Mortality effect of coronary calcification and phosphate binder choice in incident hemodialysis patients

    Get PDF
    The risk of death in hemodialysis patients treated with calcium-containing phosphate binders or sevelamer is not known. We assessed all-cause mortality in 127 patients new to hemodialysis assigned to calcium-containing binders or sevelamer after a median follow-up of 44 months from randomization. This was a predetermined secondary end point of a randomized clinical trial designed to assess progression of coronary artery calcium (CAC) scores in the two treatment arms. Thirty-four deaths occurred during the follow-up period: 23 in subjects randomized to calcium-containing phosphate binders and 11 in subjects randomized to sevelamer. Baseline CAC score was a significant predictor of mortality after adjustment for age, race, gender, and diabetes with increased mortality proportional to baseline score (P=0.002). Mortality was borderline significantly lower in subjects randomized to sevelamer (5.3/100 patient years, confidence interval (CI) (2.2–8.5) compared to those randomized to calcium-containing binders (10.6/100 patient years, CI 6.3–14.9) (P=0.05). The greater risk of death for patients treated with calcium-containing phosphate binders persisted after full multivariable adjustment (P=0.016, hazard ratio 3.1, CI 1.23–7.61). In subjects new to hemodialysis baseline CAC score was a significant predictor of all-cause mortality. Treatment with sevelamer was associated with a significant survival benefit as compared to the use of calcium-containing phosphate binders

    Juice Powder Concentrate and Systemic Blood Pressure, Progression of Coronary Artery Calcium and Antioxidant Status in Hypertensive Subjects: A Pilot Study

    Get PDF
    Because micronutrients from plants may have beneficial cardiovascular effects, the hypothesis that an encapsulated juice powder concentrate might affect several measures of vascular health was tested in free living adults at low cardiovascular risk. Blood pressure, vascular compliance, lipid and antioxidant markers, and serial electron beam tomography (to calculate a coronary artery calcium score as a measure of atherosclerosis burden), were monitored in 51 pre-hypertensive and hypertensive subjects over 2 years. By the end of follow-up, systolic and diastolic blood pressure decreased significantly (−2.4 ± 1.0 mmHg, P < 0.05 and −2.2 ± 0.6 mmHg, P < 0.001), and large artery compliance improved significantly (1.9 ± 0.6 ml mmHg−1 × 100, P < 0.01). The progression of coronary artery calcium score was smaller than expected compared with a historical database (P < 0.001). Laboratory testing showed a significant decrease in homocysteine (P = 0.05), HDL cholesterol (P = 0.025) and Apo A (P = 0.004), as well as a significant increase in β-carotene, folate, Co-Q10 and α-tocopherol (all P < 0.001). The phytonutrient concentrate we utilized induced several favorable modifications of markers of vascular health in the subjects. This study supports the notion that plant nutrients are important components of a heart healthy diet

    Performance of the PADME calorimeter prototype at the DAΦ\PhiNE BTF

    Full text link
    The PADME experiment at the DAΦ\PhiNE Beam-Test Facility (BTF) aims at searching for invisible decays of the dark photon by measuring the final state missing mass in the process e+eγ+Ae^+e^- \to \gamma+ A', with AA' undetected. The measurement requires the determination of the 4-momentum of the recoil photon, performed using a homogeneous, highly segmented BGO crystals calorimeter. We report the results of the test of a 5×\times5 crystals prototype performed with an electron beam at the BTF in July 2016

    A prototype large-angle photon veto detector for the P326 experiment at CERN

    Full text link
    The P326 experiment at the CERN SPS has been proposed with the purpose of measuring the branching ratio for the decay K^+ \to \pi^+ \nu \bar{\nu} to within 10%. The photon veto system must provide a rejection factor of 10^8 for \pi^0 decays. We have explored two designs for the large-angle veto detectors, one based on scintillating tiles and the other using scintillating fibers. We have constructed a prototype module based on the fiber solution and evaluated its performance using low-energy electron beams from the Frascati Beam-Test Facility. For comparison, we have also tested a tile prototype constructed for the CKM experiment, as well as lead-glass modules from the OPAL electromagnetic barrel calorimeter. We present results on the linearity, energy resolution, and time resolution obtained with the fiber prototype, and compare the detection efficiency for electrons obtained with all three instruments.Comment: 8 pages, 9 figures, 2 tables. Presented at the 2007 IEEE Nuclear Science Symposium, Honolulu HI, USA, 28 October - 3 November 200

    Global burden of headache disorders in children and adolescents 2007–2017

    Get PDF
    Headache disorders are prevalent and disabling conditions impacting on people of all ages, including children and adolescents with substantial impact on their school activities and leisure time. Our study aims to report specific information on headaches in children and adolescents based on the Global Burden of Disease (GBD) study, that provides estimates for incidence, prevalence, fatal and non-fatal outcomes. We relied on 2007 and 2017 GBD estimates for prevalence and Years Lived with Disability (YLDs) at the global level and in WHO regions. The results show that, migraine and tension-type headache (TTH) together account for 37.5% of all-cause prevalence and for 7% of all-cause YLDs. Over the past decade, prevalence rates showed a mild increase of TTH in all ages and of migraine alone for adolescents. The YLDs increased among females of all ages with some regional differences that might be connected to the unequal availability of effective acute and prophylactic treatments across world regions. GBD data support the need to promote public health policies and strategies including diagnosis, pharmacological and non-pharmacological treatments that are expected to help reduce the disability and burden associated to migraine and TTH among children and adolescents

    Non-pharmacological approaches to headaches: Non-invasive neuromodulation, nutraceuticals, and behavioral approaches

    Get PDF
    Significant side effects or drug interactions can make pharmacological management of headache disorders very difficult. Non-conventional and non-pharmacological treatments are be-coming increasingly used to overcome these issues. In particular, non-invasive neuromodulation, nutraceuticals, and behavioral approaches are well tolerated and indicated for specific patient categories such as adolescents and pregnant women. This paper aims to present the main approaches reported in the literature in the management of headache disorders. We therefore reviewed the available literature published between 2010 and 2020 and performed a narrative presentation for each of the three categories (non-invasive neuromodulation, nutraceuticals, and behavioral therapies). Regarding non-invasive neuromodulation, we selected transcranial magnetic stimulation, supraor-bital nerve stimulation, transcranial direct current stimulation, non-invasive vagal nerve stimulation, and caloric vestibular stimulation. For nutraceuticals, we selected Feverfew, Butterbur, Riboflavin, Magnesium, and Coenzyme Q10. Finally, for behavioral approaches, we selected biofeedback, cognitive behavioral therapy, relaxation techniques, mindfulness-based therapy, and acceptance and commitment therapy. These approaches are increasingly seen as a valid treatment option in headache management, especially for patients with medication overuse or contraindications to drug treatment. However, further investigations are needed to consider the effectiveness of these approaches also with respect to the long-term effects
    corecore