94 research outputs found
High-Definition Optical Coherence Tomography for the in vivo Detection of Demodex Mites
Background: Demodex mites are involved in different skin diseases and are commonly detected by skin scrape tests or superficial biopsies. A new high-definition optical coherence tomography (HD-OCT) with high lateral and axial resolution in a horizontal (en-face) and vertical (slice) imaging mode might offer the possibility of noninvasive and fast in vivo examination of demodex mites. Methods: Twenty patients with demodex-related skin diseases and 20 age- and gender-matched healthy controls were examined by HD-OCT. Mites per follicle and follicles per field of view were counted and compared to skin scrape tests. Results: HD-OCT images depicted mites in the en-face mode as bright round dots in groups of 3-5 mites per hair follicle. In the patients with demodex-related disease, a mean number of 3.4 mites per follicle were detected with a mean number of 2.9 infested follicles per area of view compared to a mean of 0.6 mites in 0.4 infested follicles in the controls. The skin scrape tests were negative in 21% of the patients. Conclusion: The innovative HD-OCT enables fast and noninvasive in vivo recognition of demodex mites and might become a useful tool in the diagnosis and treatment monitoring of demodex-related skin diseases. Copyright (C) 2012 S. Karger AG, Base
First Dark Matter Results from the XENON100 Experiment
The XENON100 experiment, in operation at the Laboratori Nazionali del Gran
Sasso in Italy, is designed to search for dark matter WIMPs scattering off 62
kg of liquid xenon in an ultra-low background dual-phase time projection
chamber. In this letter, we present first dark matter results from the analysis
of 11.17 live days of non-blind data, acquired in October and November 2009. In
the selected fiducial target of 40 kg, and within the pre-defined signal
region, we observe no events and hence exclude spin-independent WIMP-nucleon
elastic scattering cross-sections above 3.4 x 10^-44 cm^2 for 55 GeV/c^2 WIMPs
at 90% confidence level. Below 20 GeV/c^2, this result constrains the
interpretation of the CoGeNT and DAMA signals as being due to spin-independent,
elastic, light mass WIMP interactions.Comment: 5 pages, 5 figures. Matches published versio
Material screening and selection for XENON100
Results of the extensive radioactivity screening campaign to identify
materials for the construction of XENON100 are reported. This Dark Matter
search experiment is operated underground at Laboratori Nazionali del Gran
Sasso (LNGS), Italy. Several ultra sensitive High Purity Germanium detectors
(HPGe) have been used for gamma ray spectrometry. Mass spectrometry has been
applied for a few low mass plastic samples. Detailed tables with the
radioactive contaminations of all screened samples are presented, together with
the implications for XENON100.Comment: 8 pages, 1 figur
Machine-Part cell formation through visual decipherable clustering of Self Organizing Map
Machine-part cell formation is used in cellular manufacturing in order to
process a large variety, quality, lower work in process levels, reducing
manufacturing lead-time and customer response time while retaining flexibility
for new products. This paper presents a new and novel approach for obtaining
machine cells and part families. In the cellular manufacturing the fundamental
problem is the formation of part families and machine cells. The present paper
deals with the Self Organising Map (SOM) method an unsupervised learning
algorithm in Artificial Intelligence, and has been used as a visually
decipherable clustering tool of machine-part cell formation. The objective of
the paper is to cluster the binary machine-part matrix through visually
decipherable cluster of SOM color-coding and labelling via the SOM map nodes in
such a way that the part families are processed in that machine cells. The
Umatrix, component plane, principal component projection, scatter plot and
histogram of SOM have been reported in the present work for the successful
visualization of the machine-part cell formation. Computational result with the
proposed algorithm on a set of group technology problems available in the
literature is also presented. The proposed SOM approach produced solutions with
a grouping efficacy that is at least as good as any results earlier reported in
the literature and improved the grouping efficacy for 70% of the problems and
found immensely useful to both industry practitioners and researchers.Comment: 18 pages,3 table, 4 figure
Dark Matter Results from 100 Live Days of XENON100 Data
We present results from the direct search for dark matter with the XENON100
detector, installed underground at the Laboratori Nazionali del Gran Sasso of
INFN, Italy. XENON100 is a two-phase time projection chamber with a 62 kg
liquid xenon target. Interaction vertex reconstruction in three dimensions with
millimeter precision allows to select only the innermost 48 kg as ultra-low
background fiducial target. In 100.9 live days of data, acquired between
January and June 2010, no evidence for dark matter is found. Three candidate
events were observed in a pre-defined signal region with an expected background
of 1.8 +/- 0.6 events. This leads to the most stringent limit on dark matter
interactions today, excluding spin-independent elastic WIMP-nucleon scattering
cross-sections above 7.0x10^-45 cm^2 for a WIMP mass of 50 GeV/c^2 at 90%
confidence level.Comment: 5 pages, 5 figures; matches accepted versio
Implications on Inelastic Dark Matter from 100 Live Days of XENON100 Data
The XENON100 experiment has recently completed a dark matter run with 100.9
live-days of data, taken from January to June 2010. Events in a 48kg fiducial
volume in the energy range between 8.4 and 44.6 keVnr have been analyzed. A
total of three events have been found in the predefined signal region,
compatible with the background prediction of (1.8 \pm 0.6) events. Based on
this analysis we present limits on the WIMP-nucleon cross section for inelastic
dark matter. With the present data we are able to rule out the explanation for
the observed DAMA/LIBRA modulation as being due to inelastic dark matter
scattering off iodine at a 90% confidence level.Comment: 3 pages, 3 figure
The XENON100 Dark Matter Experiment
The XENON100 dark matter experiment uses liquid xenon (LXe) in a time
projection chamber (TPC) to search for Xe nuclear recoils resulting from the
scattering of dark matter Weakly Interacting Massive Particles (WIMPs). In this
paper we present a detailed description of the detector design and present
performance results, as established during the commissioning phase and during
the first science runs.
The active target of XENON100 contains 62 kg of LXe, surrounded by an LXe
veto of 99 kg, both instrumented with photomultiplier tubes (PMTs) operating
inside the liquid or in Xe gas. The LXe target and veto are contained in a
low-radioactivity stainless steel vessel, embedded in a passive radiation
shield. The experiment is installed underground at the Laboratori Nazionali del
Gran Sasso (LNGS), Italy and has recently published results from a 100
live-days dark matter search. The ultimate design goal of XENON100 is to
achieve a spin-independent WIMP-nucleon scattering cross section sensitivity of
\sigma = 2x10^-45 cm^2 for a 100 GeV/c^2 WIMP.Comment: 23 pages, 27 figures; version accepted by journa
Cost-based filtering for stochastic inventory control
Abstract. An interesting class of production/inventory control problems considers a single product and a single stocking location, given a stochastic demand with a known non-stationary probability distribution. Under a widely-used control policy for this type of inventory system, the objective is to find the optimal number of replenishments, their timings and their respective order-up-to-levels that meet customer demands to a required service level. We extend a known CP approach for this problem using a cost-based filtering method. Our algorithm can solve to optimality instances of realistic size much more efficiently than previous approaches, often with no search effort at all.
Material screening and selection for XENON100
Abstract Results of the extensive radioactivity screening campaign to identify materials for the construction of XENON100 are reported. This Dark Matter search experiment is operated underground at Laboratori Nazionali del Gran Sasso (LNGS), Italy. Several ultra sensitive High Purity Germanium detectors (HPGe) have been used for gamma ray spectrometry. Mass spectrometry has been applied for a few low mass plastic samples. Detailed tables with the radioactive contaminations of all screened samples are presented, together with the implications for XENON100
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