Pattern recognition techniques to reduce backgrounds in the search for the 136Xe double beta decay with gaseous TPCs

The observation of the neutrinoless double beta decay may provide essential information on the nature of neutrinos. Among the current experimental approaches, a high pressure gaseous TPC is an attractive option for the search of double beta decay due to its good energy resolution and the detailed topological information of each event. We present in this talk a detailed study of the ionization topology of the 136Xe double beta decay events in a High Pressure Xenon TPC, as well as that of the typical competing backgrounds. We define some observables based on graph theory concepts to develop automated discrimination algorithms. Our criteria are able to reduce the background level by about three orders of magnitude in the region of interest of the 136Xe Qbb for a signal acceptance of 40%. This result provides a quantitative assessment of the benefit of topological information offered by gaseous TPCs for double beta decay search, and proves that it is a promising feature in view of future experiments in the field. Possible ideas for further improvement in the discrimination algorithms and the dependency of these results with the gas diffusion and readout granularity will be also discussed.Comment: Proceedings of the Low Radioactivity Techniques Conference (LRT2013), Gran Sasso (Italy). To be published in AIP Conf. Pro

Reproducibility and clinical relevance of the ocular response analyzer in nonoperated eyes: corneal biomechanical and tonometric implications

To assess the reproducibility of the ocular response analyzer (ORA) in nonoperated eyes and the impact of corneal biomechanical properties on intraocular pressure (IOP) measurements in normal and glaucomatous eyes. METHODS: In the reliability study, two independent examiners obtained repeated ORA measurements in 30 eyes. In the clinical study, the examiners analyzed ORA and IOP-Goldmann values from 220 normal and 42 glaucomatous eyes. In both studies, Goldmann-correlated IOP measurement (IOP-ORAg), corneal-compensated IOP (IOP-ORAc), corneal hysteresis (CH), and corneal resistance factor (CRF) were evaluated. IOP differences of 3 mm Hg or greater between the IOP-ORAc and IOP-ORAg were considered outcome significant. RESULTS: Intraexaminer intraclass correlation coefficients and interexaminer concordance correlation coefficients ranged from 0.78 to 0.93 and from 0.81 to 0.93, respectively, for all parameters. CH reproducibility was highest, and the IOP-ORAg readings were lowest. The median IOP was 16 mm Hg with the Goldmann tonometer, 14.5 mm Hg with IOP-ORAg (P < 0.001), and 15.7 mm Hg with IOP-ORAc (P < 0.001). Outcome-significant results were found in 77 eyes (29.38%). The IOP-ORAc, CH, and CRF were correlated with age (r = 0.22, P = 0.001; r = -0.23, P = 0.001; r = -0.14, P = 0.02, respectively), but not the IOP-ORAg or IOP-Goldmann. CONCLUSIONS: The ORA provides reproducible corneal biomechanical and IOP measurements in nonoperated eyes. Considering the effect of ORA, corneal biomechanical metrics produces an outcome-significant IOP adjustment in at least one quarter of glaucomatous and normal eyes undergoing noncontact tonometry. Corneal viscoelasticity (CH) and resistance (CRF) appear to decrease minimally with increasing age in healthy adults

Cost-effectiveness of hip protectors in frail institutionalized elderly

A randomized controlled trial was performed to examine the cost-effectiveness of external hip protectors in the prevention of hip fractures. Since the hip protectors were not effective in preventing hip fractures in our study, the main objective became to examine whether the use of hip protectors results in lower average costs per participant in the hip protector group as compared with the control group. In addition, the average costs of a hip fracture and subsequent rehabilitation in frail, institutionalized elderly were calculated. Residents from apartment houses for the elderly, homes for the elderly and nursing homes with a high risk for hip fractures were randomized to the hip protector group (n = 276) or control group (n = 285). Costs were calculated for the hip fracture and subsequent rehabilitation until 1 year after the fracture. Six months after each hip fracture, a nurse was interviewed and after 12 months, a questionnaire was sent to the general practitioner or nursing home physician to determine the utilization of health care resources. Differences in costs between the groups were analyzed using non-parametric bootstrapping. Eighteen hip fractures occurred in the intervention group and 20 hip fractures (in 19 persons) in the control group (log rank P-value = 0.86). The average costs per participant, including the costs of the intervention, were €913 in the intervention group and 502 in the control group (cost difference of €-411; 95% confidence interval: -723; 57). The average costs of a hip fracture and subsequent rehabilitation were €8100 (95% CI: 6716-10,010). The use of hip protectors was not associated with lower costs. In addition, the average costs of a hip fracture and subsequent rehabilitation in the first year after the fracture were estimated at €8100 in institutionalized elderly. © International Osteoporosis Foundation and National Osteoporosis Foundation 2004

Prevalence and prognostic factors of disability after major trauma

Background: The primary aim of this study was to assess the health-related quality of life of survivors of severe trauma 1 year after injury, specified according to all the separate dimensions of the EuroQol-5D (EQ-5D) and the Health Utilities Index (HUI). Methods: A prospective cohort study was conducted in which all severely injured trauma patients presented at a Level I trauma center were included. After 12 months, the EQ-5D, HUI2 and HUI3 were used to analyze the health status. Results: Follow-up assessments were obtained from 246 patients (response rate, 68%). The overall population EQ-5D (median) utility score was 0.73 (EQ-5D Dutch general population norm, 0.88). HUI2, HUI3, and EQ-5D Visual Analog Scale scores were 0.81, 0.65, and 70, respectively. Eighteen percent had at least one functional limitation 1 year after trauma, and 60% reported functional limitations on two or more domains using the EQ-5D. The female gender and comorbidity were significant independent predictors of disability. Conclusion: Functional outcome and quality of life of survivors of severe injury have not returned to normal 1 year after trauma. The prevalence of specific limitations in this population is very high (40-70%). Female gender and comorbidity are predictors of long-term disability. Copyrigh

Radiopurity control in the NEXT-100 double beta decay experiment: procedures and initial measurements

We have investigated the possibility of calibrating the PMTs of scintillation detectors, using the primary scintillation produced by X-rays to induce single photoelectron response of the PMT. The high-energy tail of this response, can be approximated to an exponential function, under some conditions. In these cases, it is possible to determine the average gain for each PMT biasing voltage from the inverse of the exponent of the exponential fit to the tail, which can be done even if the background and/or noise cover-up most of the distribution. We have compared our results with those obtained by the commonly used single electron response (SER) method, which uses a LED to induce a single photoelectron response of the PMT and determines the peak position of such response, relative to the pedestal peak (the electronic noise peak, which corresponds to 0 photoelectrons). The results of the exponential fit method agree with those obtained by the SER method when the average number of photoelectrons reaching the first dynode per light/scintillation pulse is around 1.0. The SER method has higher precision, while the exponential fit method has the advantage of being useful in situations where the PMT is already in situ, being difficult or even impossible to apply the SER method, e.g. in sealed scintillator/PMT devices

Saving lives beyond 2020: The next steps

Road safety analysis can be used to understand what has been successful in the past and what needs to be changed in order to be successful to reduce severe road trauma going forward and ultimately what\u27s needed to achieve zero. This chapter covers some of the tools used to retrospectively evaluate real-life benefits of road safety measures and methods used to predict the combined effects of interventions in a road safety action plan as well as to estimate if they are sufficient to achieve targets near-term and long-term. Included are also a brief overview of methods to develop boundary conditions on what constitutes a Safe System for different road users. Further to that, the chapter lists some arguments for the need of high-quality mass and in-depth data to ensure confidence in the results and conclusions from road safety analysis. Finally, a few key messages are summarized

Smoking Status, Changes in Smoking Status and Health-Related Quality of Life: Findings from the SUN (“Seguimiento Universidad de Navarra”) Cohort

We aimed to evaluate the association between smoking, changes in smoking, and quality of life in a cohort of Spanish university graduates. Smoking habits were self-reported at baseline and four years later. Quality of life was assessed using the Short Form-36 (SF-36) at year 4. Statistical differences in SF-36 scores between groups were determined using ANCOVA with age and sex as covariates. Out of 5,234 eligible participants over 2000–2006, there were 2,639 non-smoker participants, 1,419 ex-smokers, and 1,048 smokers. Within the previous four years, 435 participants became recent quitters and 205 starters. Comparing smoking and health status in year 4, non-smokers showed better scores than the other categories of ever smoking in all dimensions except in the vitality scale value, which was similar in non-smokers and in those smoking less than 15 cigarettes/day. Comparing changes in smoking and health in year 4, continuing smokers had statistically significant worse scores than non-smokers in general health, social functioning, role-emotional and mental health, whereas recent quitters showed statistically significant improvements in role-emotional and mental health over those who had continued smoking or those who became smokers. Our findings support a dose-response relationship between cigarette consumption and a worse quality of life in general and mental health in particular. They also support that changes in smoking have an impact on health

Characterization of a medium size Xe/TMA TPC instrumented with microbulk Micromegas, using low-energy gamma-rays

NEXT-MM is a general-purpose high pressure (10 bar, ~ 25 l active volume) Xenon-based TPC, read out in charge mode with an 0.8 cm × 0.8 cm-segmented 700 cm2 plane (1152 ch) of the latest microbulk-Micromegas technology. It has been recently commissioned at University of Zaragoza as part of the R&D of the NEXT 0νββ experiment, although the experiment's first stage is currently being built based on a SiPM/PMT-readout concept relying on electroluminescence. Around 2 million events were collected during the last months, stemming from the low energy γ-rays emitted by a 241Am source when interacting with the Xenon gas (Eγ = 26, 30, 59.5 keV). The localized nature of such events around atmospheric pressure, the long drift times, as well as the possibility to determine their production time from the associated α particle in coincidence, allow the extraction of primordial properties of the TPC filling gas, namely the drift velocity, diffusion and attachment coefficients. In this work we focus on the little explored combination of Xe and trimethylamine (TMA) for which, in particular, such properties are largely unknown. This gas mixture offers potential advantages over pure Xenon when aimed at Rare Event Searches, mainly due to its Penning characteristics, wave-length shifting properties and reduced diffusion, and it is being actively investigated by our collaboration. The chamber is currently operated at 2.7 bar, as an intermediate step towards the envisaged 10 bar. We report here its performance as well as a first implementation of the calibration procedures that have allowed the extension of the previously reported energy resolution to the whole readout plane (10.6% FWHM@30 keV)