1,078 research outputs found

    Coherent and semiclassical states in magnetic field in the presence of the Aharonov-Bohm solenoid

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    A new approach to constructing coherent states (CS) and semiclassical states (SS) in magnetic-solenoid field is proposed. The main idea is based on the fact that the AB solenoid breaks the translational symmetry in the xy-plane, this has a topological effect such that there appear two types of trajectories which embrace and do not embrace the solenoid. Due to this fact, one has to construct two different kinds of CS/SS, which correspond to such trajectories in the semiclassical limit. Following this idea, we construct CS in two steps, first the instantaneous CS (ICS) and the time dependent CS/SS as an evolution of the ICS. The construction is realized for nonrelativistic and relativistic spinning particles both in (2+1)- and (3+1)- dimensions and gives a non-trivial example of SS/CS for systems with a nonquadratic Hamiltonian. It is stressed that CS depending on their parameters (quantum numbers) describe both pure quantum and semiclassical states. An analysis is represented that classifies parameters of the CS in such respect. Such a classification is used for the semiclassical decompositions of various physical quantities.Comment: 35 pages, 2 figures. Some typos in (77), (101), and (135) corrected with respect to the published version. Results unchange

    Influence of the Hip on Patients with Patellofemoral Pain Syndrome: A Systematic Review

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    Context: Patellofemoral pain syndrome (PFPS) is one of the most common conditions limiting athletes. There is a growing body of evidence suggesting that dysfunction at the hip may be a contributing factor in PFPS. Data Sources: MEDLINE (1950–September 2010), CINAHL (1982–September 2010), and SPORTDiscus (1830–September 2010) were searched to identify relevant research to this report. Study Selection: Studies were included assessing hip strength, lower extremity kinematics, or both in relation to PFPS were included. Data Extraction: Studies included randomized controlled trials, quasi-experimental designs, prospective epidemiology, case-control epidemiology, and cross-sectional descriptive epidemiology in a scientific peer-reviewed journal. Results: PFPS is associated with decreased hip strength, specifically at the abductors and external rotators. There is a correlation between PFPS and faulty hip mechanics (adduction and internal rotation). Conclusions: There is a link between the strength and position of the hip and PFPS. These patients have a common deficit once symptomatic. Hip strengthening and a coordination program may be useful in a conservative treatment plan for PFPS

    Minimizing Injuries and Enhancing Performance in Golf through Training Programs

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    Context: Golf is a popular sport, particularly in older populations. Regardless of age and skill level, golfers risk injury to the back, shoulder, wrist and hand, elbow, and knee. Because of the unique compressive, shear, rotational, and lateral bending forces created in the lumbar region during the golf swing, the primary sport-related malady experienced by amateurs and professionals is low back pain. Extrinsic and intrinsic injury risk factors have been reported in the literature. A growing body of evidence supports the prescription of strength training routines to enhance performance and reduce the risk of injury. Evidence Acquisition: Relevant studies were reviewed on golf injuries, swing mechanics, training routines, and general training program design. The following electronic databases were used to identify research relevant to this report: MEDLINE (from 1950–November 2009), CINAHL (1982–November 2009), and SPORTDiscus (1830–November 2009). Results: Injuries may be associated with lack of warm-up, poor trunk flexibility and strength, faulty swing technique, and overuse. Conclusions: Implementing a training program that includes flexibility, strength, and power training with correction of faulty swing mechanics will help the golfer reduce the likelihood of injury and improve overall performance

    Proposta de novo sistema de alerta para doenças do cafeeiro.

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    Neste trabalho será exibido um resumo da proposta a ser apresentada, expondo o objetivo do projeto do novo sistema e as ferramentas indicadas para seu desenvolvimento

    Dummy Cb sebagai Alat Simulator Kubikel untuk Pemeliharaan Preventif dan Korektif Guna Mengurangi Frekuensi Padam Penyulang 20 Kv (Aplikasi pada Sistem Scada 20 Kv Pt.pln (Persero) Apd Jateng & DIY)

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    Meira Dwi Primanto, Priyo Sasmoko, in paper dummy CB as cubicle simulator for preventive and corrective maintenance to reduce off frequency 20 KV feeders (20 KV scada system at APD Central Java and Yogyakarta) explain that in 2013, the APD PT.PLN Central Java and Yogyakarta are conducting integration to SCADA at 20 KV feeders in distribution substation. For the next stage has been installed SCADA maintenance should be done periodically. Maintenance can be planned or due to interference with the SCADA system. Maintenance is usually done by the team must perform SCADA Distribution feeder outages and transfer of the load. In the installation of equipment, SCADA team should get a working permit to shut down the feeder, and to transfer the load to another feeder, so that the work has to get permission. SCADA systems are already installed requires maintenance to keep the system reliability. When maintenance SCADA, feeders should be extinguished, whereas for medium voltage customers such as factories, hospitals, and airports should always be channeled electrical energy. Feeder outages and load Delegation KWH lost causes. To the authors attempt to provide solutions that can overcome the missing KWH with a tool innovations made. The author makes a tool such as a dummy circuit breaker simulator 20 KV cubicles. This tool serves Especially when employees perform maintenance or investigation SCADA Disorders, which aims for 20 KV feeders should not be extinguished when performing preventive and corrective maintenance. So the number of frequency of feeder outages can be reduced

    Core Stabilization Exercise Prescription, Part I: Current Concepts in Assessment and Intervention

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    Context: Injury to the low back can cause significant pain and dysfunction, which can affect an athlete’s performance and result in time lost from sport. A common conservative treatment is therapeutic core stabilization exercises, which can address pain and musculoskeletal dysfunction in patients with low back pathology. Evidence Acquisition: MEDLINE and CINAHL were searched (from 1966 to March 2013) to identify relevant research. Keywords and keyword combinations searched included motor control exercise, segmental stabilization, core stabilization, transversus abdominis, multifidi, and low back pain. Results: There are 2 popular rehabilitation strategies to assess core function and promote core stabilization. Each has been developed based on biomechanical models of lumbar segmental stability and observed motor control dysfunction in patients with low back pain. Conclusion: Controversy exists among clinical and research groups as to the optimal strategy for an athlete with low back pain

    Core Stabilization Exercise Prescription, Part 2: A Systematic Review of Motor Control and General (Global) Exercise Rehabilitation Approaches for Patients with Low Back Pain

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    Context: Therapeutic exercises are frequently prescribed to patients with low back pain. Numerous exercise programs for patients with low back pain have been described. Many of these treatment programs are based on 1 of 2 popular rehabilitation strategies: a motor control exercise approach or a general exercise approach. Data Sources: PubMed clinical queries from 1966 to March 2013 for keyword combinations including motor control exercise, core stability exercise, therapeutic exercise, general exercise, global exercise, local exercise, transversus abdominis, segmental stabilization, and low back pain. Study Selection: Randomized controlled trials that assessed the effects of a motor control exercise approach, a general exercise approach, or both for patients with low back pain that were published in scientific peer-reviewed journals. Data Extraction: Included studies underwent appraisal for exercise intervention and outcomes. Results: Fifteen studies were identified (8, motor control exercise approach without general exercise comparison; 7, general exercise approach with or without motor control exercise approach comparison). Current evidence suggests that exercise interventions may be effective at reducing pain or disability in patients with low back pain. Conclusion: Stabilization exercises for patients with low back pain may help to decrease pain and disability. It may not be necessary to prescribe exercises purported to restore motor control of specific muscles

    Organização estratégica de plataforma para caracterização espacial de riscos no setor agropecuário e agroflorestal.

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