12,928 research outputs found
Vertex Reconstruction Using a Single Layer Silicon Detector
Typical vertex finding algorithms use reconstructed tracks, registered in a
multi-layer detector, which directly point to the common point of origin. A
detector with a single layer of silicon sensors registers the passage of
primary particles only in one place. Nevertheless, the information available
from these hits can also be used to estimate the vertex position, when the
geometrical properties of silicon sensors and the measured ionization energy
losses of the particles are fully exploited. In this paper the algorithm used
for this purpose in the PHOBOS experiment is described. The vertex
reconstruction performance is studied using simulations and compared with
results obtained from real data. The very large acceptance of a single-layered
multiplicity detector permits vertex reconstruction for low multiplicity events
where other methods, using small acceptance subdetectors, fail because of
insufficient number of registered primary tracks.Comment: accepted for publication in Nucl. Instr. Meth.
Equine digital tendons show breedâspecific differences in their mechanical properties that may relate to athletic ability and predisposition to injury
Background Throughout the ages, human subjects have selected horse breeds for their locomotor capacities. Concurrently, tissue properties may have diversified because of specific requirements of different disciplines. Objectives The aim of this study was to compare the biomechanical properties of tendons with different functions between equine breeds traditionally selected for racing or sport. Study design This study used ex vivo tendons and compared the mechanical properties of the common digital extensor tendon (CDET) and superficial digital flexor tendon (SDFT) between racehorses (Thoroughbred [TB]) and sports horses (Friesian Horse [FH], Warmblood [WB]). Methods The SDFT and CDET of FH (n = 12), WBs (n = 12) and TBs (n = 8) aged 3-12 years were harvested. The cross sectional area (cm(2)), maximal load (N), ultimate strain (%), ultimate stress (MPa) and elastic modulus (MPa) were determined and tested for significant differences between the breeds (P<0.05). Results The SDFT from WB horses had a significantly lower elastic modulus than TB horses and failed at a higher strain and load than both FHs and TBs. The mechanical properties of the CDET did not differ between breeds. In agreement with previous studies, the CDET failed at a higher stress and had a higher elastic modulus than the SDFT and, for the WB group of horses only, failed at a significantly lower strain. Interestingly, the mode of failure differed between breeds, particularly with respect to the FHs. Main limitations The exercise history of horses used in this study was unknown and the age-range was relatively large; both these factors may have influenced the absolute properties reported in this study. Conclusions This study shows for the first time that mechanical properties of the SDFT differ between breeds. These properties are likely to be related to selection for high-speed vs. an extravagant elastic gait and may be an important indicator of performance ability. The is available in Spanish - see Supporting Informatio
Two-dimensional global manifolds of vector fields
We describe an efficient algorithm for computing two-dimensional stable and unstable manifolds of three-dimensional vector fields. Larger and larger pieces of a manifold are grown until a sufficiently long piece is obtained. This allows one to study manifolds geometrically and obtain important features of dynamical behavior. For illustration, we compute the stable manifold of the origin spiralling into the Lorenz attractor, and an unstable manifold in zeta(3)-model converging to an attracting limit cycle
Resilience markers for safer systems and organisations
If computer systems are to be designed to foster resilient
performance it is important to be able to identify contributors to resilience. The
emerging practice of Resilience Engineering has identified that people are still a
primary source of resilience, and that the design of distributed systems should
provide ways of helping people and organisations to cope with complexity.
Although resilience has been identified as a desired property, researchers and
practitioners do not have a clear understanding of what manifestations of
resilience look like. This paper discusses some examples of strategies that
people can adopt that improve the resilience of a system. Critically, analysis
reveals that the generation of these strategies is only possible if the system
facilitates them. As an example, this paper discusses practices, such as
reflection, that are known to encourage resilient behavior in people. Reflection
allows systems to better prepare for oncoming demands. We show that
contributors to the practice of reflection manifest themselves at different levels
of abstraction: from individual strategies to practices in, for example, control
room environments. The analysis of interaction at these levels enables resilient
properties of a system to be âseenâ, so that systems can be designed to explicitly
support them. We then present an analysis of resilience at an organisational
level within the nuclear domain. This highlights some of the challenges facing
the Resilience Engineering approach and the need for using a collective
language to articulate knowledge of resilient practices across domains
Geoneutrinos in Borexino
This paper describes the Borexino detector and the high-radiopurity studies
and tests that are integral part of the Borexino technology and development.
The application of Borexino to the detection and studies of geoneutrinos is
discussed.Comment: Conference: Neutrino Geophysics Honolulu, Hawaii December 14-16, 200
Authentic Corporate Social Responsibility Based on Authentic Empowerment: An Exemplary Business Leadership Case
Authors Dillon, Back, and Manz examine the underpinnings of genuine or authentic Corporate Social Responsibility (CSR), noting the direct nexus between stakeholder empowerment and the socially-responsible actions of authentic leaders. Such an empowering leadership approachâ involving structural, psychological, developmental, and financial components â is particularly exemplified by a family-owned (Back) wine and cheese company (Fairview Trust), situate in South Africa
Precision Measurement Of The Neutron's Beta Asymmetry Using Ultra-Cold Neutrons
A measurement of A_ÎČ, the correlation between the electron momentum and neutron (n) spin (the beta asymmetry) in n beta-decay, together with the n lifetime, provides a method for extracting fundamental parameters for the charged-current weak interaction of the nucleon. In particular when combined with decay measurements, one can extract the V_(ud) element of the CKM matrix, a critical element in CKM unitarity tests. By using a new SD_2 super-thermal source at LANSCE, large fluxes of UCN (ultra-cold neutrons) are expected for the UCNA project. These UCN will be 100% polarized using a 7 T magnetic field, and directed into the ÎČ spectrometer. This approach, together with an expected large reduction in backgrounds, will result in an order of magnitude reduction in the critical systematic corrections associated with current n ÎČ-asymmetry measurements. This paper will give an overview of the UCNA AÎČ measurement as well as an update on the status of the experiment
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An Investigation into the Effect of Consumer Experience Tourism on Brand Loyalty and Purchasing Behavior
Brand loyalty and repeat purchase intentions are accepted as important and inextricably intertwined phenomena in contemporary marketing literature, with many studies pertaining to this area. In order to achieve customer loyalty, it is important for companies to create strong bonds between their products or brands and consumers. Consumer Experience Tourism (CET) has been increasingly used as a strategic marketing tool in an attempt to strengthen such bonds, particularly by producers of frequently purchased consumer staples such as food and beverages. With no studies to date identified as having tested the effects of CET on medium to long-term consumer brand loyalty and purchasing behavior, how such behavior differs from that of consumers who have had other non-CET experiential interactions with the product or brand, and indeed those consumers who have had no experiential interaction with the product or brand, companies have a dilemma in how to treat this activity. Should they treat it as a worthwhile marketing expense that will reap long-term rewards, or as a tourist activity that should either cover its costs or show a profit due to limited benefits?
This dissertation consists of three studies that investigate the effects of CET on brand loyalty and purchasing behavior. Study 1 obtained 415 valid surveys from CET visitors to a single winery, investigating perceived product quality, perceived service quality, and the effects of charging (versus not charging) on purchasing behavior, and found that under conditions of both highly perceived product quality and highly perceived service quality, there were no significant differences in purchasing behavior. Study 2 obtained 437 valid surveys from CET visitors to the winery of survey in Study 1 who had visited over a six-year period, as well as consumers of the brands who had not engaged in CET, and found significant differences in attitudinal brand loyalty but not in purchasing behavior. Study 3 attempted to replicate the effects of a CET using a Consumer Experience Event (CEE), with a pre-event tracking survey obtaining 74 valid responses, followed by a post-event tracking survey that obtained 51 valid responses. It was found that this type of experience remote from the brand home was able to replicate many of the CET attributes and effects. This research therefore extends CET as a theoretical construct and begins to resolve the CET marketerâs dilemma
Characterization of the Role of the Small Ubiquitin-like Modifier (SUMO) on Nuclear Localization and Proteolysis of the Thyroid Hormone Receptor (TR)
The small ubiquitin-like modifier (SUMO) is involved in post-translational modification of proteins and is characterized by its role in regulation of a variety of cellular processes. The objective of this thesis was to characterize the role SUMO has in modification of the thyroid hormone receptor (TR). TR is a regulatory transcription factor that, in most cases when the ligand (T3) is not bound, represses gene expression through the recruitment of co-repressors. When T3 is bound to TR, the co-repressors are released and co-activators are recruited, resulting in positive gene expression mediated by a particular thyroid hormone response element (TRE). Previous research has identified the import and export proteins involved in nuclear localization of TR. Post-translational modification, however, has only begun to be characterized. In terms of proteolysis, TR is degraded through poly-ubiquitination; but it is unclear whether ubiquitin binding is correlated with sumoylation. SUMO sites for TR have been previously identified, and their role in TR-mediated gene expression demonstrated. Here, the role SUMO plays in nuclear localization and proteolysis of TR through its interaction with ubiquitin binding is characterized. Mutant constructs of TR that could not be sumoylated were synthesized and cloned into GFP. For nuclear localization assays, the constructs were transfected into HeLa cells and quantitatively scored for the ratio of fluorescence intensity in the nucleus versus the cytosol using region of interest (ROI) analysis. Coimmunoprecipitation followed by western analysis, was conducted in order to identify the relationship between sumoylation and ubiquitination. The nuclear localization experiments showed no changes in nuclear localization of the SUMO-deficient TR compared to the wild-type TR. Coimmunoprecipitation suggested that there may be a higher level of ubiquitination when TR was not sumoylated. However, varying levels of cellular ubiquitin make this finding inconclusive. Overall, this thesis demonstrates that SUMO is not directly involved in nuclear localization of TR; however, it may play a role in enhancing the binding of ubiquitin, ultimately suggesting that sumoylation may be involved in proteolysis of TR
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