7,077 research outputs found
Kondo effect of Co adatoms on Ag monolayers on noble metal surfaces
The Kondo temperature of single Co adatoms on monolayers of Ag on Cu
and Au(111) is determined using Scanning Tunneling Spectroscopy. of Co on
a single monolayer of Ag on either substrate is essentially the same as that of
Co on a homogenous Ag(111) crystal. This gives strong evidence that the
interaction of surface Kondo impurities with the substrate is very local in
nature. By comparing found for Co on Cu, Ag, and Au (111)-surfaces we
show that the energy scale of the many-electron Kondo state is insensitive to
the properties of surface states and to the energetic position of the projected
bulk band edges.Comment: 4 pages, 3 figure
Which one to choose? New evidence on the choice and success of job search methods
This paper provides new evidence on the choice and success of six different job search channels comprising the public employment agency, advertisements in newspapers and journals, internet job search, recruitment agencies, direct applications, and the social network. In addition, job search intensity and its effects are regarded. Relying on panel data for Germany, we are able to consider observed and unobserved heterogeneity in the estimation. In line with findings for other countries, the results show that consideration of various channels in individual job search increases the employment chances. With regard to the determinants, the estimates exhibit clear differences between the job search channels and with respect to search intensity. The results for success of the job search channels reveal that the public employment agency is ineffective and even harms the employment chances of the unemployed job seekers. In contrast, direct application for jobs and internet job search provide successful channels and increase the employment chances
Kondo temperature of magnetic impurities at surfaces
Based on the experimental observation, that only the close vicinity of a
magnetic impurity at metal surfaces determines its Kondo behaviour, we
introduce a simple model which explains the Kondo temperatures observed for
cobalt adatoms at the (111) and (100) surfaces of Cu, Ag, and Au. Excellent
agreement between the model and scanning tunneling spectroscopy (STS)
experiments is demonstrated. The Kondo temperature is shown to depend on the
occupation of the d-level determined by the hybridization between adatom and
substrate with a minimum around single occupancy.Comment: 4 pages, 2 figure
Scale space consistency of piecewise constant least squares estimators -- another look at the regressogram
We study the asymptotic behavior of piecewise constant least squares
regression estimates, when the number of partitions of the estimate is
penalized. We show that the estimator is consistent in the relevant metric if
the signal is in , the space of c\`{a}dl\`{a}g functions equipped
with the Skorokhod metric or equipped with the supremum metric.
Moreover, we consider the family of estimates under a varying smoothing
parameter, also called scale space. We prove convergence of the empirical scale
space towards its deterministic target.Comment: Published at http://dx.doi.org/10.1214/074921707000000274 in the IMS
Lecture Notes Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org
Mediating and Moderating Effects on the Association between Vision Loss and Depression among an Older Population
The purpose of this study was to gain a more holistic view of the association between depression and visual functioning by examining possible mediating and moderating factors. Previous research has established a linkage between low life satisfaction and coping skills and depressive symptoms. Results of this study contribute to this literature by indicating that life satisfaction partially mediates the relationship between visual functioning and depression. Furthermore, a significant coping by visual functioning interaction was discovered, revealing that among this sample, visual impairment is associated with higher levels of depression among individuals with low coping skills; however, little effect was found for individuals with high coping skills. Results provide support for the importance of early screening of satisfaction with life and coping among older individuals experiencing age-related visual impairment
Show me your body and I tell you how hold you are: a non-invasive methodto define 6 life history-classes in Risso's dolphins (Grampus griseus), using an identified trial population in the Atlantic
European Cetacean Society Conference Workshop, Galway, Ireland, 25th March 2012."[…]. The objective of this paper is to present a new non-intrusive and inexpensive method to classify six life history stages in Risso's dolphins: from newborn calf to old-adult. We propose an age-class indicator model using the scarification patterns and the species unique discoloration process. We developed two methods and tested these among 52 rankers to examine if our proposed methods could be applied by anybody and if they would conform with our age class model. We also investigated the possible differences in the scarification patterns between genders. We used a longterm followed identified population of Risso's dolphins in the Azores to set up our test methods and report our present results.
Behavioural responses of Risso’s dolphin, Grampus griseus, to remote biopsy sampling
25th Conference of the European Cetacean Society. Long-terms datasets on marine mammals: learning from the past to manage the future, Cadiz, Spain, 21-23 March 2011.Biopsy sampling from free-ranging cetaceans is a widespread method used in various biological studies. Since this is an intrusive research technique, it’s important to determine its impact. We examined the short-term behavioural reactions of Risso’s dolphins, Grampus griseus (2.6-4m in length), off Pico Island, to remote biopsy sampling. Biopsies were conducted over a consecutive two year period using a crossbow with Finn Larsen bolts and tips. Sampling followed a number of precautionary rules, including taking samples only in calm seas, when animals were travelling; no more than 1-4 shots per group; and females with nursing calves were not exposed to sampling. Behavioural responses were analysed by visual observation using two scales of behavioural reactions: i) the reaction of the targeted individual, and ii) the reaction of the focal group to which the targeted individual belonged. We defined five categories of intensity of behavioural response (none, low, medium, high, very high) and five types of display response (quick dive, QD; diving & leaving, D&L; jumping, J; tail slapping, TS; and speeding away at surface, SS). A total of 189 shots were made (115 hits, 74 miss) during 61 survey days. Tissue was obtained in 83% of the hits. No significant differences were found between hits and misses in behavioural responses or types of display (Kruskal Wallis test). In 9% of the cases there was no visible reaction, while most (48%) behavioural responses were of low intensity. The frequencies of the display responses differed significantly from each other (chi-squared test). The types QD and D&L constituted 79% of the responses. Group reaction was observed during 1/5 of the shots, (main behaviour D&L-51%). Although biopsy sampling is an invasive method, our results indicate that if basic precaution rules are followed low intensity behavioural responses can be expected for half of the time
A comparative study of the efficiency of chart versus computer-generated contrast sensitivity testing in glaucoma patients and controls
Purpose. The goal of this study was to assess the efficiency of chart vs. computergenerated contrast sensitivity tests in glaucoma patients and controls. Methods. A total of 64 individuals (30 young controls, 18 older controls, 16 glaucoma patients) were tested for contrast sensitivity using 4 different tests. Two tests determined contrast sensitivity (CS) for detecting large targets with sharp borders. One of these was the MARS printed chart, and the other a computerized number search test by Bailey. The second assessment determined spatial contrast sensitivity (SCS) for sinusoidal grating targets at several spatial frequencies. One of these was the printed Vistech chart, the other a computerized test by Faubert. Results. Both CS tests showed a decrease in the glaucoma group versus both the control groups (p < 0.001). The tests for SCS demonstrated a decrease in sensitivity both with age (p < 0.001) and in the presence of glaucoma (p < 0.001) across all spatial frequencies. Conclusion. The data indicated that SCS was superior in separating the three study groups. Neither of the computer-generated tests was more sensitive than its printed counterpart
Robust nonparametric detection of objects in noisy images
We propose a novel statistical hypothesis testing method for detection of
objects in noisy images. The method uses results from percolation theory and
random graph theory. We present an algorithm that allows to detect objects of
unknown shapes in the presence of nonparametric noise of unknown level and of
unknown distribution. No boundary shape constraints are imposed on the object,
only a weak bulk condition for the object's interior is required. The algorithm
has linear complexity and exponential accuracy and is appropriate for real-time
systems. In this paper, we develop further the mathematical formalism of our
method and explore important connections to the mathematical theory of
percolation and statistical physics. We prove results on consistency and
algorithmic complexity of our testing procedure. In addition, we address not
only an asymptotic behavior of the method, but also a finite sample performance
of our test.Comment: This paper initially appeared in 2010 as EURANDOM Report 2010-049.
Link to the abstract at EURANDOM repository:
http://www.eurandom.tue.nl/reports/2010/049-abstract.pdf Link to the paper at
EURANDOM repository: http://www.eurandom.tue.nl/reports/2010/049-report.pd
Many-core applications to online track reconstruction in HEP experiments
Interest in parallel architectures applied to real time selections is growing
in High Energy Physics (HEP) experiments. In this paper we describe performance
measurements of Graphic Processing Units (GPUs) and Intel Many Integrated Core
architecture (MIC) when applied to a typical HEP online task: the selection of
events based on the trajectories of charged particles. We use as benchmark a
scaled-up version of the algorithm used at CDF experiment at Tevatron for
online track reconstruction - the SVT algorithm - as a realistic test-case for
low-latency trigger systems using new computing architectures for LHC
experiment. We examine the complexity/performance trade-off in porting existing
serial algorithms to many-core devices. Measurements of both data processing
and data transfer latency are shown, considering different I/O strategies
to/from the parallel devices.Comment: Proceedings for the 20th International Conference on Computing in
High Energy and Nuclear Physics (CHEP); missing acks adde
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