655 research outputs found

    MIMAC : A micro-tpc matrix for directional detection of dark matter

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    Directional detection of non-baryonic Dark Matter is a promising search strategy for discriminating WIMP events from background. However, this strategy requires both a precise measurement of the energy down to a few keV and 3D reconstruction of tracks down to a few mm. To achieve this goal, the MIMAC project has been developed. It is based on a gaseous micro-TPC matrix, filled with CF4 and CHF3. The first results on low energy nuclear recoils (H, F) obtained with a low mono-energetic neutron field are presented. The discovery potential of this search strategy is discussed and illustrated by a realistic case accessible to MIMAC.Comment: 6 pages, Proc. of the fifth international symposium on large TPCs for low energy rare event detection, Paris, France, Dec. 2010. To appear in Journal of Physic

    Evaluation of building envelope retrofit techniques for reducing energy needs for space cooling.

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    One of the fastest growing sources of new energy demand is space cooling. According to EU-studies a four-fold growth in air-conditioned space is likely to take place between 1990 and 2020. The energy savings achievable in the end-use space cooling depend on a number of variables related to the building envelope, the plants and to some extent the behaviour of occupants. They are hence complex to evaluate and consequently often underrepresented in energy efficiency programmes and National Plans. This paper is based on some preliminary results of the IEE project KeepCool 2. It discusses in particular: a methodology for bottom-up assessment of the energy savings related to "sustainable summer comfort" solutions; reference base case building typologies are analyzed in 5 European climates, and dynamic simulations are used to calculate the reductions in the energy need for cooling which can be achieved by specific retrofit actions (e.g. additions of effective solar protections, increased thermal insulation, night ventilation, increase of active mass by PCM, low solar absorbance surfaces,...); situations where mechanical cooling can be avoided are evaluated using the Adaptive Comfort model, according to the norm EN 15251. case studies of buildings with good summer comfort and low energy consumption performances, according to the ten steps of the KC2 procedure. the analysis of case studies of "comfort policies" adopted by public and private bodies to ensure summer comfort with low energy consumption (commitments to give priority to heat load reductions instead of introducing mechanical cooling, relaxed dress codes, low thermal insulation chairs, local air velocity increase)

    Conclusion

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    The outcome of a three-day conference held at the African Studies Centre, Leiden, The Netherlands, in September 1998, this book on the 1997 Kenya general elections is organized in four parts: the direct pre-electoral background; technical and national analysis of the general elections, including the performance of the Electoral Commission, international observation, and the role of the media; regional studies focusing on the grassroots level of Kenyan politics at the Kenya Coast, among the Kenya Somali, in Ukambani, Meru and Embu, Central Province and Nairobi, and Maasailand, among the Kalenjin and the Gusii, in Luo Nyanza, and in Western Province and Trans-Nzoia district; and the Njoro and Laikipia violence in the aftermath of the elections, political developments in 1998 and 1999, and the meaning of electoral politics in Kenya. Contributors: Francis Ang'ila Aywa, Norbert Braakhuis, Marren Akatsa-Bukachi, Fran‡ois Grignon, Charles Hornsby, Joe Kadhi, Peter Mwangi Kagwanja, Karuti Kanyinga, Musambayi Katumanga, Wambui Kimathi, Herv‚ Maupeu, Alamin Mazrui, Kimani Njogu, Adams Oloo, Kenneth Ombongi, Marc-Antoine P‚rouse de Montclos, Ralph-Michael Peters, Marcel RuttenASC – Publicaties niet-programma gebonde

    MPGDs in Compton imaging with liquid-xenon

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    The interaction of radiation with liquid xenon, inducing both scintillation and ionization signals, is of particular interest for Compton-sequences reconstruction. We report on the development and recent results of a liquid-xenon time-projection chamber, dedicated to a novel nuclear imaging technique named "3 gamma imaging". In a first prototype, the scintillation is detected by a vacuum photomultiplier tube and the charges are collected with a MICROMEGAS structure; both are fully immersed in liquid xenon. In view of the final large-area detector, and with the aim of minimizing dead-zones, we are investigating a gaseous photomultiplier for recording the UV scintillation photons. The prototype concept is presented as well as preliminary results in liquid xenon. We also present soft x-rays test results of a gaseous photomultiplier prototype made of a double Thick Gaseous Electron Multiplier (THGEM) at normal temperature and pressure conditions.Comment: presented at MPGD09, CRETE, June 2009; to be published in JINST Proceedings, PDF, 10 pages, 11 figure

    Using time-use diaries to track changing behavior across successive stages of COVID-19 social restrictions

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    How did people change their behavior over the different phases of the UK COVID-19 restrictions, and how did these changes affect their risk of being exposed to infection? Time-use diary surveys are unique in providing a complete chronicle of daily behavior: 24-h continuous records of the populations’ activities, their social context, and their location. We present results from four such surveys, collected in real time from representative UK samples, both before and at three points over the course of the current pandemic. Comparing across the four waves, we find evidence of substantial changes in the UK population’s behavior relating to activities, locations, and social context. We assign different levels of risk to combinations of activities, locations, and copresence to compare risk-related behavior across successive “lockdowns.” We find evidence that during the second lockdown (November 2020), there was an increase in high-risk behaviors relative to the first (starting March 2020). This increase is shown to be associated with more paid work time in the workplace. At a time when capacity is still limited both in respect of immunization and track–trace technology, governments must continue to rely on changes in people’s daily behaviors to contain the spread of COVID-19 and similar viruses. Time-use diary information of this type, collected in real time across the course of the COVID-19 pandemic, can provide policy makers with information to assess and quantify changes in daily behaviors and the impact they are likely to have on overall behavioral-associated risks

    Testicular infarction in the newborn: Ultrasound findings

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    Three patients with neonatal testicular torsion and infarction (two bilateral, one unilateral) are presented with a distinctive sonographic appearance. All five testes appeared inhomogeneously hypoechoic and each was surrounded by a brightly echogenic rim. Whereas surgical exploration was required in the past to establish the diagnosis of testicular infarction in the neonate, sonographic demonstration of the abnormality in the appearance of the testicular parenchyma permits nonoperative diagnosis. Because surgical salvage of the testis in the setting of neonatal extravaginal torsion is thought to be quite rare, the necessity of removing the testis is less clear when the diagnosis is established preoperatively.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46692/1/247_2005_Article_BF02013166.pd

    Urachal carcinoma presenting with chronic mucusuria: a case report

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    Urachal adenocarcinoma is a rare tumor and represents 0.17–0.34% of all bladder tumors. It has an insidious course and variable clinical presentation. We present a case report of a 58 year old white male with an urachal cyst who suffered irritative voiding symptoms and long term mucusuria, since childhood. After surgical removal of the cyst with a partial cystectomy a mucus adenocarcinoma was diagnosed histologically
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