2,590 research outputs found
Josephson Coupling in the Dissipative State of a Thermally Hysteretic -SQUID
Micron-sized superconducting interference devices (-SQUIDs) based on
constrictions optimized for minimizing thermal runaway are shown to exhibit
voltage oscillations with applied magnetic flux despite their hysteretic
behavior. We explain this remarkable feature by a significant supercurrent
contribution surviving deep into the resistive state, due to efficient heat
evacuation. A resistively shunted junction model, complemented by a thermal
balance determining the amplitude of the critical current, describes well all
experimental observations, including the flux modulation of the (dynamic)
retrapping current and voltage by introducing a single dimensionless parameter.
Thus hysteretic -SQUIDs can be operated in the voltage read-out mode with
a faster response. The quantitative modeling of this regime incorporating both
heating and phase dynamics paves the way for further optimization of
-SQUIDs for nano-magnetism.Comment: 10 pages, 11 figures, Revise
Controlling hysteresis in superconducting constrictions with a resistive shunt
We demonstrate control of the thermal hysteresis in superconducting
constrictions by adding a resistive shunt. In order to prevent thermal
relaxation oscillations, the shunt resistor is placed in close vicinity of the
constriction, making the inductive current-switching time smaller than the
thermal equilibration time. We investigate the current-voltage characteristics
of the same constriction with and without the shunt-resistor. The widening of
the hysteresis-free temperature range is explained on the basis of a simple
model.Comment: 6 pages, 7 figures, including Supplementary Informatio
Exploring transmission Kikuchi diffraction using a Timepix detector
Electron backscatter diffraction (EBSD) is a well-established scanning electron microscope (SEM)-based technique [1]. It allows the non-destructive mapping of the crystal structure, texture, crystal phase and strain with a spatial resolution of tens of nanometers. Conventionally this is performed by placing an electron sensitive screen, typically consisting of a phosphor screen combined with a charge coupled device (CCD) camera, in front of a specimen, usually tilted 70° to the normal of the exciting electron beam. Recently, a number of authors have shown that a significant increase in spatial resolution is achievable when Kikuchi diffraction patterns are acquired in transmission geometry; that is when diffraction patterns are generated by electrons transmitted through an electron-transparent, usually thinned, specimen. The resolution of this technique, called transmission Kikuchi diffraction (TKD), has been demonstrated to be better than 10 nm [2,3]. We have recently demonstrated the advantages of a direct electron detector, Timepix [4,5], for the acquisition of standard EBSD patterns [5]. In this article we will discuss the advantages of Timepix to perform TKD and for acquiring spot diffraction patterns and more generally for acquiring scanning transmission electron microscopy micrographs in the SEM. Particularly relevant for TKD, is its very compact size, which allows much more flexibility in the positioning of the detector in the SEM chamber. We will furthermore show recent results using Timepix as a virtual forward scatter detector, and will illustrate the information derivable on producing images through processing of data acquired from different areas of the detector. We will show results from samples ranging from gold nanoparticles to nitride semiconductor nanorods
Athletic Training Student and Student Aide Clinical Task Allowance in the Secondary School Setting
Purpose: Athletic training student aides (SA) are minors in high school that participate in an athletic training experience under the supervision of secondary school athletic trainers (SSAT). The NATA published an official statement on the proper supervision of SAs related to task allowance. As SSATs may also supervise athletic training students (ATSs), it is important to understand the differences in both. Therefore, the objective was to explore the training, task allowance, and perspectives of SAs and ATSs by SSATs during clinical experiences. Methods: We used a cross-sectional, web-based survey for this study. SSATs (n=3,567) from the ATLAS database were recruited and 614 participants (age=39±11years, years credentialed=12±9years) completed the study. An online survey was developed to reflect the NATA official statement for task allowance and supervision of SAs and ATSs. Dependent variables included requirements and task allowance of the SA and ATS based on supervision (direct, autonomous, and restricted), and the personal perceptions from SSATs. Results: 76.5% of SSATs reported having SAs involved in their clinical practice. Less than 50% of SSATs implemented recommended trainings related to emergency preparedness, first aid, and patient privacy. When exploring task allowance, most SSATs were following best practice guidelines for job-related tasks. Additionally, SSATs were allowing ATSs to perform more tasks autonomously as compared to SAs. Conclusions: SSATs are mostly following best practice recommendations for task allowance, whereby they are providing supervision to SAs in the appropriate areas and not allowing certain duties. However, 100% compliance was not met, thus increasing risks to patients and the profession. SSATs should improve training and preparedness for the SAs involved in their clinical practice Additionally, SSATs are allowing ATSs to perform job-related tasks autonomously or with directed supervision during clinical experiences with the exception to administrative tasks and autonomous clinical-decision making
Athletic Trainers’ Knowledge of Legal Practice within Information Technology and Social Media
Purpose: As healthcare and technology continue to connect in daily practice, athletic trainers (ATs) must be knowledgeable of the governing acts for ethical and legal clinical practice. This is vital to ensure ethical and legal practice as a clinician and protection of confidential protected health information (PHI). The objective of this study was to assess certified athletic trainers’ knowledge of regulations within technology and social media (SoMe). Methods: Certified ATs were recruited from the National Athletic Trainers’ Association membership database. Respondents completed an instrument of 28 questions, including 16 participant demographics, clinical site demographics, SoMe usage and general questions, and a 12-item knowledge assessment tool on a web-based survey platform. Validity of the instrument was determined through a Delphi panel of experts in athletic training, healthcare lawyers and an information technologist. We analyzed data using descriptive statistics. Results: Respondents reported a Master’s degree as their highest earned (n=106, 72.6%) with 33.6% of those degrees being at the professional level (n=49). Respondents predominately worked in the public secondary school setting (n=43, 29.5%) and worked 8-9 hours per day (n=78, 53.4%). Respondents self-reported an average of five active SoMe accounts with Facebook® (n=120,, 81.6%), LinkedIn® (n=75, 51%), Instagram® (n=70, 47.6%), Twitter® (n=70, 47.6%), Pinterest® (n=64, 43.5%), and Snapchat® (n=64, 43.5%) being the most common sites. Within their athletic training clinic, respondents predominately reported (n=76, 51.7%) that all their computers had a virtual private network, and had a SoMe policy that was enforced to some extent (n=63, 42.9%). Respondents (n=136, 92.5%) stated that they have not reported someone for a breach of HIPAA, and have not been reported themselves (n=146, 99.3%); however, respondents (n=16, 10.8%) indicated they had one or more full faced photos of patients on their SoMe accounts, breaching HIPAA. The majority of respondents have had formal education on HIPAA regulations (n=115, 78.2%). On the knowledge assessment, Respondents correctly scored 7.7±1.9 out of 12 possible points (mean score=59.2±14.5%). Conclusions: Respondents lacked the appropriate knowledge regarding HIPAA and Health Information Technology for Economic and Clinical Health (HITECH) Act regulations, and application of this knowledge within SoMe. Future research should focus on educational interventions of technology advancements for safe and legal practice as an AT
Strong Interactive Massive Particles from a Strong Coupled Theory
Minimal walking technicolor models can provide a nontrivial solution for
cosmological dark matter, if the lightest technibaryon is doubly charged.
Technibaryon asymmetry generated in the early Universe is related to baryon
asymmetry and it is possible to create excess of techniparticles with charge
(-2). These excessive techniparticles are all captured by , creating
\emph{techni-O-helium} ``atoms'', as soon as is formed in Big
Bang Nucleosynthesis. The interaction of techni-O-helium with nuclei opens new
paths to the creation of heavy nuclei in Big Bang Nucleosynthesis. Due to the
large mass of technibaryons, the ``atomic'' gas decouples from the
baryonic matter and plays the role of dark matter in large scale structure
formation, while structures in small scales are suppressed. Nuclear
interactions with matter slow down cosmic techni-O-helium in Earth below the
threshold of underground dark matter detectors, thus escaping severe CDMS
constraints. On the other hand, these nuclear interactions are not sufficiently
strong to exclude this form of Strongly Interactive Massive Particles by
constraints from the XQC experiment. Experimental tests of this hypothesis are
possible in search for in balloon-borne experiments (or on the ground)
and for its charged techniparticle constituents in cosmic rays and
accelerators. The ``atoms'' can cause cold nuclear transformations in
matter and might form anomalous isotopes, offering possible ways to exclude (or
prove?) their existence.Comment: 41 pages, 4 figure
Inelastic Diffraction and Spectroscopy of Very Weakly Bound Clusters
We study the coherent inelastic diffraction of very weakly bound two body
clusters from a material transmission grating. We show that internal
transitions of the clusters can lead to new separate peaks in the diffraction
pattern whose angular positions determine the excitation energies. Using a
quantum mechanical approach to few body scattering theory we determine the
relative peak intensities for the diffraction of the van der Waals dimers
(D_2)_2 and H_2-D_2. Based on the results for these realistic examples we
discuss the possible applications and experimental challenges of this coherent
inelastic diffraction technique.Comment: 15 pages + 5 figures. J. Phys. B (in press
Stabilized lasers for advanced gravitational wave detectors
Second generation gravitational wave detectors require high power lasers with more than 100 W of output power and with very low temporal and spatial fluctuations. To achieve the demanding stability levels required, low noise techniques and adequate control actuators have to be part of the high power laser design. In addition feedback control and passive noise filtering is used to reduce the fluctuations in the so-called prestabilized laser system (PSL). In this paper, we discuss the design of a 200 W PSL which is under development for the Advanced LIGO gravitational wave detector and will present the first results. The PSL noise requirements for advanced gravitational wave detectors will be discussed in general and the stabilization scheme proposed for the Advanced LIGO PSL will be described
Stabilized high-power laser system for the gravitational wave detector advanced LIGO
An ultra-stable, high-power cw Nd:YAG laser system, developed for the ground-based gravitational wave detector Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory), was comprehensively characterized. Laser power, frequency, beam pointing and beam quality were simultaneously stabilized using different active and passive schemes. The output beam, the performance of the stabilization, and the cross-coupling between different stabilization feedback control loops were characterized and found to fulfill most design requirements. The employed stabilization schemes and the achieved performance are of relevance to many high-precision optical experiments
The Effects of Deep Oscillation Therapy for Individuals with Lower-Leg Pain
Purpose: Lower extremity (LE) pain accounts for 13-20% of injuries in the active population. LE pain has been contributed to inflexibility and fascial restrictions. Deep oscillation therapy (DOT) has been proposed to improve range of motion and reduce pain following musculoskeletal injuries. Therefore, our objective was to determine the effectiveness of DOT on ankle dorsiflexion range of motion (ROM) and pain in individuals with and without lower-leg pain. Methods: We used a single blind, pre-post experimental study in a research laboratory. Thirty-two active participants completed this study. Sixteen individuals reporting lower-leg pain and sixteen non-painful individuals completed the study. Participants received a single session of DOT performed by one researcher to their affected limb or matched limb. The intervention parameters included a 1:1 mode and 70-80% dosage. The intervention began by stimulating the lymphatic channels at the cisterna chyli, the inguinal lymph node, and the popliteal lymph node at a frequency of 150 Hz all for a minute each. Next, the researcher treated the triceps surae complex for 11 minutes at three different frequencies. Finally, the participant was treated distal to the popliteal lymph node at 25 Hz for 5 minutes. The main outcome measures included pain using the VAS and ankle dorsiflexion ROM with the weight-bearing lunge test (WBLT). Statistical analyses included descriptive statistics and F-test comparisons between and within groups. Results: The average WBLT measures for all participants increased 0.6 cm, which not to the minimal detectable change for passive ankle dorsiflexion ROM. Significant differences from pre-post measures were identified for pain on the VAS. Conclusion: While increases in ROM were identified, the difference was not clinically important. DOT was successful in decreasing lower-leg pain
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