38,038 research outputs found
A robotic platform for high-throughput electrochemical analysis of chalcopyrite leaching
A novel robotic platform for combinatorial screening of ionic liquid-based Cu extraction from chalcopyrite with real-time, in situ monitoring of dissolved copper.</p
Development of a method to identify foot strike on an arena surface: application to jump landing
Foot strike can be difficult to determine using kinematics alone, particularly when studying equine activities on more compliant surfaces, so this study was done with the aim of developing and validating a method to determine foot strike on an arena surface that can be used in conjunction with kinematics alone, and of applying the method in the context of measuring foot strike during jump landing on an arena surface. A low-cost contact mat was developed. The timing of the contact mat switching ‘on’ was compared to the timing of a force platform onset of 20 N, load and loading rate at foot strike. Two groups of 25 participants were used in two separate studies to validate the contact mat: the first measured the difference in timing with respect to two different activities (running and stepping down from a box), and the second measured the difference in timing with respect to 1- and 2-cm depths of an arena surface during running. In a third study, the mat was used to measure leading limb foot strike of six horses during jump landing, and these data were compared to kinematics from a palmar marker on the hoof wall. All data were recorded at 500 Hz. A consistent difference in delay was found between the mat and force platform onset, and as a result, no significant differences (P>0.05) in timing delay between different loading rates or depths were found. During jump landing, foot strike (determined from the mat) occurred after the vertical velocity minima and the acceleration maxima for the hoof marker, but it occurred before the point where the rate of vertical displacement began to reduce. In conclusion, further work is needed to enhance these techniques, but these preliminary results indicate that this method may be effective in determining foot strike for field-based applications
Knot Theory: from Fox 3-colorings of links to Yang-Baxter homology and Khovanov homology
This paper is an extended account of my "Introductory Plenary talk at Knots
in Hellas 2016" conference We start from the short introduction to Knot Theory
from the historical perspective, starting from Heraclas text (the first century
AD), mentioning R.Llull (1232-1315), A.Kircher (1602-1680), Leibniz idea of
Geometria Situs (1679), and J.B.Listing (student of Gauss) work of 1847. We
spend some space on Ralph H. Fox (1913-1973) elementary introduction to diagram
colorings (1956). In the second section we describe how Fox work was
generalized to distributive colorings (racks and quandles) and eventually in
the work of Jones and Turaev to link invariants via Yang-Baxter operators, here
the importance of statistical mechanics to topology will be mentioned. Finally
we describe recent developments which started with Mikhail Khovanov work on
categorification of the Jones polynomial. By analogy to Khovanov homology we
build homology of distributive structures (including homology of Fox colorings)
and generalize it to homology of Yang-Baxter operators. We speculate, with
supporting evidence, on co-cycle invariants of knots coming from Yang-Baxter
homology. Here the work of Fenn-Rourke-Sanderson (geometric realization of
pre-cubic sets of link diagrams) and Carter-Kamada-Saito (co-cycle invariants
of links) will be discussed and expanded.
Dedicated to Lou Kauffman for his 70th birthday.Comment: 35 pages, 31 figures, for Knots in Hellas II Proceedings, Springer,
part of the series Proceedings in Mathematics & Statistics (PROMS
Vacuum phototriodes for the CMS electromagnetic calorimeter endcap
The measurement of scintillation light from the lead tungstate crystals of the Compact Muon Solenoid (CMS) electromagnetic calorimeter (ECAL) poses a substantial technical challenge, particularly in the endcap regions, where the radiation levels are highest. The photodetectors must be fast, sensitive, radiationhard, and operate with significant internal gain in a magnetic field of 4 Tesla. The measured performance characteristics of the first batches of series production vacuum phototriodes (VPT), developed to satisfy the needs of CMS, will be described
The best of both worlds: The benefits of open-specialized and open-diverse syndication networks for new venture success
Open networks give actors non-redundant information that is diverse, while closed networks offer redundant information that is easier to interpret. Integrating arguments about network structure and the similarity of actors’ knowledge, we propose two types of network configurations that combine diversity and ease of interpretation. Closed-diverse networks offer diversity in actors’ knowledge domains and shared third-party ties to help in interpreting that knowledge. In open-specialized networks, structural holes offer diversity, while shared interpretive schema and overlap between received information and actors’ prior knowledge help in interpreting new information without the help of third parties. In contrast, actors in open-diverse networks suffer from information overload due to the lack of shared schema or overlapping prior knowledge for the interpretation of diverse information, and actors in closed-specialized networks suffer from overembeddedness because they cannot access diverse information. Using CrunchBase data on early-stage venture capital investments in the U.S. information technology sector, we test the effect of investors’ social capital on the success of their portfolio ventures. We find that ventures have the highest chances of success if their syndicating investors have either open-specialized or closed-diverse networks. These effects are manifested beyond the direct effects of ventures’ or investors’ quality and are robust to controlling for the possibility that certain investors could have chosen more promising ventures at the time of first funding
Exact Results for Wilson Loops in Superconformal Chern-Simons Theories with Matter
We use localization techniques to compute the expectation values of
supersymmetric Wilson loops in Chern-Simons theories with matter. We find the
path-integral reduces to a non-Gaussian matrix model. The Wilson loops we
consider preserve a single complex supersymmetry, and exist in any N=2 theory,
though the localization requires superconformal symmetry. We present explicit
results for the cases of pure Chern-Simons theory with gauge group U(N),
showing agreement with the known results, and ABJM, showing agreement with
perturbative calculations. Our method applies to other theories, such as
Gaiotto-Witten theories, BLG, and their variants.Comment: 32 page
Temporal trends in mode, site and stage of presentation with the introduction of colorectal cancer screening: a decade of experience from the West of Scotland
background: Population colorectal cancer screening programmes have been introduced to reduce cancer-specific mortality through the detection of early-stage disease. The present study aimed to examine the impact of screening introduction in the West of Scotland.
methods: Data on all patients with a diagnosis of colorectal cancer between January 2003 and December 2012 were extracted from a prospectively maintained regional audit database. Changes in mode, site and stage of presentation before, during and after screening introduction were examined.
results: In a population of 2.4 million, over a 10-year period, 14 487 incident cases of colorectal cancer were noted. Of these, 7827 (54%) were males and 7727 (53%) were socioeconomically deprived. In the postscreening era, 18% were diagnosed via the screening programme. There was a reduction in both emergency presentation (20% prescreening vs 13% postscreening, P0.001) and the proportion of rectal cancers (34% prescreening vs 31% pos-screening, P0.001) over the timeframe. Within non-metastatic disease, an increase in the proportion of stage I tumours at diagnosis was noted (17% prescreening vs 28% postscreening, P0.001).
conclusions: Within non-metastatic disease, a shift towards earlier stage at diagnosis has accompanied the introduction of a national screening programme. Such a change should lead to improved outcomes in patients with colorectal cancer
Extraction of Airways with Probabilistic State-space Models and Bayesian Smoothing
Segmenting tree structures is common in several image processing
applications. In medical image analysis, reliable segmentations of airways,
vessels, neurons and other tree structures can enable important clinical
applications. We present a framework for tracking tree structures comprising of
elongated branches using probabilistic state-space models and Bayesian
smoothing. Unlike most existing methods that proceed with sequential tracking
of branches, we present an exploratory method, that is less sensitive to local
anomalies in the data due to acquisition noise and/or interfering structures.
The evolution of individual branches is modelled using a process model and the
observed data is incorporated into the update step of the Bayesian smoother
using a measurement model that is based on a multi-scale blob detector.
Bayesian smoothing is performed using the RTS (Rauch-Tung-Striebel) smoother,
which provides Gaussian density estimates of branch states at each tracking
step. We select likely branch seed points automatically based on the response
of the blob detection and track from all such seed points using the RTS
smoother. We use covariance of the marginal posterior density estimated for
each branch to discriminate false positive and true positive branches. The
method is evaluated on 3D chest CT scans to track airways. We show that the
presented method results in additional branches compared to a baseline method
based on region growing on probability images.Comment: 10 pages. Pre-print of the paper accepted at Workshop on Graphs in
Biomedical Image Analysis. MICCAI 2017. Quebec Cit
On chains in -closed topological pospaces
We study chains in an -closed topological partially ordered space. We give
sufficient conditions for a maximal chain in an -closed topological
partially ordered space such that contains a maximal (minimal) element.
Also we give sufficient conditions for a linearly ordered topological partially
ordered space to be -closed. We prove that any -closed topological
semilattice contains a zero. We show that a linearly ordered -closed
topological semilattice is an -closed topological pospace and show that in
the general case this is not true. We construct an example an -closed
topological pospace with a non--closed maximal chain and give sufficient
conditions that a maximal chain of an -closed topological pospace is an
-closed topological pospace.Comment: We have rewritten and substantially expanded the manuscrip
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