1,692 research outputs found
A Search for pair production of the LSP at the CLIC via RPV Decays
In this work we consider pair production of LSP tau-sneutrinos at the Compact
Lineer Collider. We assume that tau-sneutrinos decays in to e\textmu pair via
RPV interactions. Backgroundless subprocess
is analyzed in details. Achievable limits on
at and CL are
obtained depending on mass.Comment: 8 pages, 5 figure
Surface Modification and Metal Printing Using Atmospheric Pressure Plasma
Non-thermal atmospheric plasma sources are at the centre of a growing new field of research that promises significant benefits in areas ranging from catalysis to medicine. The main value of atmospheric pressure sources lie in their ability to generate highly energetic and reactive species under near-ambient conditions. This characteristic makes atmospheric plasma an appealing alternative to well-established vacuum plasma processes. In this study, radio frequency atmospheric pressure plasma sources are used for modification of metal oxide surfaces and direct metal deposition. In atmospheric pressure plasma afterglow, plasma electrons are shown to be capable of reducing Cu2O films, this is proven by applying an external electric field to collect or to retard plasma electrons and observing the evolution of the oxide film. Using a micro-plasma jet, Cu2O and SnO2 are demonstrated to be completely reduced to their parent metals when exposed to helium plasma. A reducing plasma is required to induce partial reduction in TiO2, WO3 and ZnO, generating oxygen deficiencies. Oxygen deficient TiO2, also known as black titania is a well-known defective metal oxide photocatalyst. In this work, a facile method for producing black titania is developed using reducing plasma jets. This method improves photocatalyic efficiencies of nano-porous anatase up to sixfold while dispensing the need for vacuum or high pressure equipment. Deposition of conductive metals is a topic of ongoing research, with an aim to develop techniques and precursors that can enable printing of electrical circuits onto unconventional substrates. In this work, a novel technique for metal printing using plasma jets is developed. The method developed in this work enables single-step deposition of conductors from lowcost metal salt based precursors. Using aerosolized CuSO4 in the plasma jet stream, it is shown that metallic traces can be deposited on a large variety surfaces with fine spatial control
Reaction Pathways Based on the Gradient of the Mean First-Passage Time
Finding representative reaction pathways is necessary for understanding
mechanisms of molecular processes, but is considered to be extremely
challenging. We propose a new method to construct reaction paths based on mean
first-passage times. This approach incorporates information of all possible
reaction events as well as the effect of temperature. The method is applied to
exemplary reactions in a continuous and in a discrete setting. The suggested
approach holds great promise for large reaction networks that are completely
characterized by the method through a pathway graph.Comment: v2; 4 pages including 5 figure
Analysis of the root canal configuration and C-shaped canal frequency of mandibular second molars: a cone beam computed tomography study
Background: Mandibular second molars frequently show variation in root canal configurations. The patients with C-shaped canals are quite challenging in dental practice. C-shaped canals have a poor prognosis in terms of debridement, obturation, and restoration. The aim of this study was to investigate the root canal configuration of mandibular second molar teeth and to determine the frequency of C-shaped canals in mandibular second molars.
Materials and methods: We designed a retrospective study using cone beam computed tomography (CBCT) images and 256 CBCT images were retrieved from the archived records of Necmettin Erbakan University Faculty of Dentistry,Konya, Turkey. The root canal configurations were evaluated according to Vertucci’s classification and C-shaped canal configurations were identified using the method of Fan et al. The frequency in percentages was calculated for C-shapedcanals in CBCT scans.
Results: Of the 444 mandibular second molars, the most frequent canal morphology in the mesial roots was Vertucci type IV (40.3%), followed by type II (27.5%). The distal roots were predominantly type I (92.9%), followed by types III (3.5%) and II (2.5%). Forty-seven (10.6%) teeth had C-shaped canals.
Conclusions: Clinicians should be concerned about the different types of canal configurations. Knowledge of these anatomical variations will facilitate the endodontic practice
Overlap Dirac Operator, Eigenvalues and Random Matrix Theory
The properties of the spectrum of the overlap Dirac operator and their
relation to random matrix theory are studied. In particular, the predictions
from chiral random matrix theory in topologically non-trivial gauge field
sectors are tested.Comment: 3 pages latex with 1 postscript figure. Talk presented at
LATTICE99(topology
Comparison of cone-beam computed tomography and panoramic radiography for mandibular morphometry
Background: The aim of this study was to compare the morphological differences in the mandible between patients with six age groups and to detect the correlation between these parameters on panoramic radiography (PR) and cone-beam computed tomography (CBCT).
Materials and methods: A total of 121 subjects (50 males and 71 females) were included in the study and were divided into six age groups (10–19, 20–29, 30–39, 40–49, 50–59, and 60–69) on the basis of the chronological age. CBCT and PR methods were used to record the mandibular measurements for the same 121 patients. Differences between male and female mandibular morphometric measurements, between right and left side measurements, and differences in age subgroups compared by using independent samples t-test, paired samples t-test, and one-way ANOVA test, respectively. P < 0.05 value was considered statistically significant for all analysis.
Results: Males mostly have higher mandibular measurement values. There were statistically significant differences between CBCT and PR measurements (p < 0.05). PR mostly showed higher values than CBCT measurements.
Conclusions: Based on the fact that PRs showing significant differences from CBCT in the morphometric measurements made on mandible, it is recommended that forensic doctors and anthropologists consider this information in their age and gender prediction studies
Efficiency of energy transfer in a light-harvesting system under quantum coherence
We investigate the role of quantum coherence in the efficiency of excitation
transfer in a ring-hub arrangement of interacting two-level systems, mimicking
a light-harvesting antenna connected to a reaction center as it is found in
natural photosynthetic systems. By using a quantum jump approach, we
demonstrate that in the presence of quantum coherent energy transfer and
energetic disorder, the efficiency of excitation transfer from the antenna to
the reaction center depends intimately on the quantum superposition properties
of the initial state. In particular, we find that efficiency is sensitive to
symmetric and asymmetric superposition of states in the basis of localized
excitations, indicating that initial state properties can be used as a
efficiency control parameter at low temperatures.Comment: Extended version of original paper. 7 pages, 2 figure
In vitro tooth cleaning efficacy of electric toothbrushes around brackets
This in vitro study assessed the cleaning efficacy of different electric toothbrushes around upper incisor brackets. Standard and Mini Diamond™ brackets were fixed on black-stained teeth. The teeth were coated with white titanium oxide and brushed in a machine twice for 1 minute each. Twelve different brush heads with either a wiping or an oscillating-rotating action were tested. After brushing, the teeth were scanned, the black surfaces were assessed planimetrically and a modified plaque index for orthodontic patients (PIOP) was introduced. Tooth areas, which were black again after brushing indicated tooth surface contact of the filaments and were expressed as a percentage of total area. The remaining white areas around the brackets indicated 'plaque-retentive' niches. Analysis of variance was used for individual comparison of the brush types. Bonferroni/Dunn adjustment was applied for multiple testing. The Sonicare® toothbrush handle with the brush head 'Compact ProResults' (81.7 per cent) and the brush head 'Standard ProResults' (80.8 per cent), as well as the sonic Waterpik® toothbrush SR 800E with the standard brush head (78.2 per cent), showed statistically significantly better cleaning efficacy than all others. The poorest cleaning efficacy was observed for the oscillating-rotating Braun Oral-B Professional Care with the brush head 'Ortho' (less than 50 per cent). The planimetric findings were in correspondence with the results of the PIOP assessment. Cleaning efficacy of electric toothbrushes around brackets on upper incisors was different between the tested brushes. The PIOP was practicable, effective, and easy to use, although it has to be verified in a clinical stud
Stabilizing sodium hypochlorite at high pH: effects on soft tissue and dentin
NaOH-stabilized NaOCl solutions have a higher alkaline capacity and are thus more proteolytic than standard counterparts
Noise Dressing of Financial Correlation Matrices
We show that results from the theory of random matrices are potentially of
great interest to understand the statistical structure of the empirical
correlation matrices appearing in the study of price fluctuations. The central
result of the present study is the remarkable agreement between the theoretical
prediction (based on the assumption that the correlation matrix is random) and
empirical data concerning the density of eigenvalues associated to the time
series of the different stocks of the S&P500 (or other major markets). In
particular the present study raises serious doubts on the blind use of
empirical correlation matrices for risk management.Comment: Latex (Revtex) 3 pp + 2 postscript figures (in-text
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