5,206 research outputs found
WIMPs search by scintillators: possible strategy for annual modulation search with large-mass highly-radiopure NaI(Tl)
The DAMA experiments are running deep underground in the Gran Sasso National
Laboratory. Several interesting results have been achieved so far. Here a
maximum likelihood method to search for the WIMP annual modulation signature is
discussed and applied to a set of preliminary test data collected with large
mass highly radiopure NaI(Tl) detectors. Various related technical arguments
are briefly addressed.Comment: 6 pages, 4 figures, LaTex. Contributed paper to TAUP97; to appear in
the Proceeding
Mutation of Directed Graphs -- Corresponding Regular Expressions and Complexity of Their Generation
Directed graphs (DG), interpreted as state transition diagrams, are
traditionally used to represent finite-state automata (FSA). In the context of
formal languages, both FSA and regular expressions (RE) are equivalent in that
they accept and generate, respectively, type-3 (regular) languages. Based on
our previous work, this paper analyzes effects of graph manipulations on
corresponding RE. In this present, starting stage we assume that the DG under
consideration contains no cycles. Graph manipulation is performed by deleting
or inserting of nodes or arcs. Combined and/or multiple application of these
basic operators enable a great variety of transformations of DG (and
corresponding RE) that can be seen as mutants of the original DG (and
corresponding RE). DG are popular for modeling complex systems; however they
easily become intractable if the system under consideration is complex and/or
large. In such situations, we propose to switch to corresponding RE in order to
benefit from their compact format for modeling and algebraic operations for
analysis. The results of the study are of great potential interest to mutation
testing
SWINE WASTE PHYTOREMEDIATION USING DUCKWEED (Landoltia punctata, Les & Crawford) IN A FULL SCALE PLANT
Banner Apresentado em Congresso: 11th International Conference, Heraklion, Crete, Greece PhytotechnologiesThe large amount of nitrogen and phosphorous compounds found in pig manure has caused ecological imbalances, with eutrophication of major river basins in the producing regions. Therefore, the aquatic macrophytes group named duckweeds (Araceae; Lemnoideae) have been successfully used for phytoextraction and rhizodegradation of nutrient and heavy metals from swine waste, generating further a biomass with high protein content. The present study evaluated the phytoremediation of nitrogen and phosphorus from swine waste using the duckweed Landoltia punctata and also their protein biomass production as by-product
Assessing the feasibility of a life history calendar to measure HIV risk and health in older South Africans
Life history calendars capture patterns of behavior over time, uncovering transitions and trajectories. Despite the growing numbers of older persons living with HIV in southern Africa, little is known about how HIV testing and risk unfold in this population. Operationalizing a life course approach with the use of an innovative Testing and Risk History Calendar [TRHC], we collected pilot data on older South Africans’ risk and HIV testing. We found older persons were able to provide (1) reference points to facilitate recall over a 10-year period, (2) specifics about HIV tests during that decade, and (3) details that contextualize the testing data, such as living arrangements, relationships, and health status. Interviewer debriefing sessions after each interview captured information on context and links across domains. On a larger scale, the TRHC has potential to reveal pathways between sexual behavior, HIV testing and risk perception, and health at older ages
DAMA annual modulation effect and asymmetric mirror matter
The long-standing model-independent annual modulation effect measured by DAMA
Collaboration is examined in the context of asymmetric mirror dark matter,
assuming that dark atoms interact with target nuclei in the detector via
kinetic mixing between mirror and ordinary photons, both being massless. The
relevant ranges for the kinetic mixing parameter are obtained taking into
account various existing uncertainties in nuclear and particle physics
quantities as well as characteristic density and velocity distributions of dark
matter in different halo models.Comment: 27 pages, 5 figures, 2 tables; version in publication on Eur. Phys.
J.
Stochastic precipitation modeling using circulation patterns to analyze climate impact on floods
This paper presents the conditioning of a precipitation model to objectively classified circulation patterns (CP). The application of CPs is considered useful with regards to model accuracy improvement and preparation of a downscaling model by using CPs classified with climate model data. As this study aims to produce rainfall as input for derived flood frequency analyses, the validation focuses on extreme values and precipitation events. The analysis is carried out by modifications of a well tested alternating renewal precipitation model
INFLUENCE OF TOE CLIPS ON MECHANICAL CHARACTERISTICS OF SPRINT CYCLING
INTRODUCTION: Toe-clips are assumed to enhance the mechanical efficiency of pedaling. However, the effect of toe-clips on power production during the maximal sprint has not been extensively studied, especially when friction loaded cycle ergometers are used (Arsac et al., 1996, Capmal and Vandewalle, 1997). The aim of this study was to evaluate the effect of toe clips during maximal sprints performed on a friction loaded ergometer.
METHODS: Force, velocity and power-production in cycling were studied during all-out sprints with (WI) and without (WO) toe-clips on a friction loaded ergometer. This friction loaded cycle ergometer (Monark 818E) was specifically equipped with both an optical encoder and a strain gauge in order to measure the instantaneous flywheel velocity and the friction force, respectively (Arsac et al., 1996). The power output at each pedal down stroke was computed as the product of velocity and total force (inertial force + friction force). Values of maximal force (F), maximal velocity (V), maximal power (P), optimal force at P (FP) and optimal velocity at P (VP) were determined. Twenty-four subjects volunteered for this study. They were specialists in cycling, whose age, height and body mass were 24 ± 5 years (mean ± SD), 178.3 ± 5.4 cm and 69 ± 7 kg respectively. Each subject performed four maximal sprints of 6-s duration with different (i) shoe-pedal interface (WI or WO) and (ii) friction force applied to the friction belt (0.5 or 1.1 N.kg-1 body mass).
RESULTS: The mechanical data obtained in the WI and WO conditions are presented in table 1. F, V, P and FP were significantly higher in the WI than in the WO condition. These differences were observed at both 0.5 and 1.1 N.kg-1. VP was higher in the WI condition at 1.1 N.kg-1 only. See text for legend.
DISCUSSION: Values of F, V and P were in agreement with the literature (Arsac et al., 1996, Capmal and Vandewalle, 1997). The significant enhancement observed on mechanical force and power production in the WI compared to the WO condition further support the hypothesis that toe clips could have a positive effect on the performance of sprint cycling. Higher force and power in WI are probably due to the fact that toe clips allow greater and longer activity of flexor and extensor lower limb muscles during a complete pedal revolution (Tate and Sherman, 1977). However, VP was not improved in the WI condition at 0.5 N.kg-1, suggesting that the toe clips effect is more efficient at high friction force and high power.
REFERENCES: Arsac, L.M. et al. (1996). Eur. J. Appl. Physiol. 74, 100-106.
Capmal, S. and Vandewalle, H. (997). Eur. J. Appl. Physiol. 76, 375-379.
Tate, J. and Sherman, G. (1977). Bicycling 18, 57
Using full-scale duckweed ponds as the finish stage for swine waste treatment with a focus on organic matter degradation
Artigo Publicado em: IWA - Water Science & TechnologyThe rapid increase in the number of swine has caused pronounced environmental impacts worldwide, especially on water resources. As an aggregate, smallholdings have an important role in South American pork production, contributing to the net diffusion of pollution. Thus, duckweed ponds have been successfully used for swine waste polishing, mainly for nutrient removal. Few studies have been carried out to assess organic matter degradation in duckweed ponds. Hence, the present study evaluated the efficiency of two full-scale duckweed ponds for organic matter reduction of swine waste on small pig farms. Duckweed ponds, in series, received the effluent after an anaerobic biodigester and storage pond, with a flow rate of 1 m3 day 1. After 1 year of monitoring, an improvement in effluent quality was observed, with a reduction in biochemical oxygen demand (BOD) and total chemical oxygen demand (tCOD), respectively, of 94.8 and 96.7%, operating at a loading rate of approximately 27 kgBOD ha 1 day 1 and 131 kgCOD ha 1 day 1. Algae inhibition due to duckweed coverage was strongly observed in the pond effluent, where chlorophyll a and turbidity remained below 25 μg L 1 and 10 NTU. Using the study conditions described herein, duckweed ponds were shown to be a suitable technology for swine waste treatment, contributing to the environmental sustainability of rural areas
On the Neutralino as Dark Matter Candidate - II. Direct Detection
Evaluations of the event rates relevant to direct search for dark matter
neutralino are presented for a wide range of neutralino masses and for various
detector materials of preeminent interest. Differential and total rates are
appropriately weighted over the local neutralino density expected on
theoretical grounds.Comment: (18 pages plain TeX, 24 figures not included, available from the
authors) DFTT-38/9
Observations of annual modulation in direct detection of relic particles and light neutralinos
The long-standing model-independent annual modulation effect measured by the
DAMA Collaboration, which fulfills all the requirements of a dark matter annual
modulation signature, and the new result by the CoGeNT experiment that shows a
similar behavior are comparatively examined under the hypothesis of a dark
matter candidate particle interacting with the detectors' nuclei by a coherent
elastic process. The ensuing physical regions in the plane of the dark
matter-particle mass versus the dark matter-particle nucleon cross-section are
derived for various galactic halo models and by taking into account the impact
of various experimental uncertainties. It is shown that the DAMA and the CoGeNT
regions agree well between each other and are well fitted by a supersymmetric
model with light neutralinos which satisfies all available experimental
constraints, including the most recent results from CMS and ATLAS at the CERN
Large Hadron Collider.Comment: 13 pages, 7 figure
- …