1,493 research outputs found

    Nonlinear Elastic Material Property Estimation of Lower Extremity Residual Limb Tissues

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    The interface stresses between the residual limb and prosthetic socket have been studied to investigate prosthetic fit. Finite-element models of the residual limb-prosthetic socket interface facilitate investigation of the mechanical interface and may serve as a potential tool for future prosthetic socket design. However, the success of such residual limb models to date has been limited, in large part due to inadequate material formulations used to approximate the mechanical behavior of residual limb soft tissues. Nonlinear finite-element analysis was used to simulate force-displacement data obtained during in vivo rate-controlled (1, 5, and 10 mm/s) cyclic indentation of the residual limb soft tissues of seven individuals with transtibial amputation. The finite-element models facilitated determination of an appropriate set of nonlinear elastic material coefficients for bulk soft tissue at discrete clinically relevant test locations. Axisymmetric finite-element models of the residual limb bulk soft tissue in the vicinity of the test location, the socket wall and the indentor tip were developed incorporating contact analysis, large displacement, and large strain, and the James-Green-Simpson nonlinear elastic material formulation. Model dimensions were based on medical imaging studies of the residual limbs. The material coefficients were selected such that the normalized sum of square error (NSSE) between the experimental and finite-element model indentor tip reaction force was minimized. A total of 95% of the experimental data were simulated using the James-Green-Simpson material formulation with an NSSE less than 5%. The respective James-Green-Simpson material coefficients varied with subject, test location, and indentation rate. Therefore, these coefficients cannot be readily extrapolated to other sites or individuals, or to the same site and individual some time after testing

    Origin of gamma-ray emission in the shell of Cassiopeia A

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    Non-thermal X-ray emission from the shell of Cassiopeia A (Cas A) has been an interesting subject of study, as it provides information about relativistic electrons and their acceleration mechanisms in the shocks. Chandra X-ray observatory revealed the detailed spectral and spatial structure of this SNR in X-rays. The spectral analysis of Chandra X-ray data of Cas A shows unequal flux levels for different regions of the shell, which can be attributed to different magnetic fields in those regions. Additionally, the GeV gamma-ray emission observed by Large Area Telescope on board Fermi Gamma Ray Space Telescope showed that the hadronic processes are dominating in Cas A, a clear signature of acceleration of protons. In this paper we aim to explain the GeV-TeV gamma-ray data in the context of both leptonic and hadronic scenario. We modeled the multi-wavelength spectrum of Cas A. We use synchrotron emission process to explain the observed non-thermal X-ray fluxes from different regions of the shell. These result in estimation of the model parameters, which are then used to explain TeV gamma-ray emission spectrum. We also use hadronic scenario to explain both GeV and TeV fluxes simultaneously. We show that a leptonic model alone cannot explain the GeV-TeV data. Therefore, we need to invoke a hadronic model to explain the observed GeV-TeV fluxes. We found that although pure hadronic model is able to explain the GeV-TeV data, a lepto-hadronic model provides the best fit to the data.Comment: Accepted in A&

    Comprehending Turkish sentences using word order, thematic roles, and case

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    A core aspect of sentence comprehension is assigning thematic roles such as agents and patients to nouns. Turkish, a flexible word order language with accusative case-marking, allows us to compare the relative effect of word order, case-marking, and thematic reversibility in sentence comprehension. We conducted two spoken language comprehension experiments to investigate the relationships among these factors. Native Turkish-speaking adults were faster and more accurate in comprehending sentences with default word order than those with scrambled word order; case-marked sentences than non-casemarked sentences; and sentences with thematically irreversible nouns than those with reversible nouns. The effect of word order depended on the reversibility of the nouns, and case-marking had little-to-no effect on comprehension when the nouns were thematically irreversible. Our results suggest that while Turkish speakers use multiple cues to map thematic roles onto nouns, there are diminishing returns of facilitation with each additional source of information. These results give support to race-based models of sentence comprehension

    Bases of Power and Conflict Intervention Strategy: A Study on Turkish Managers

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    Purpose – This study developed an influence perspective for managerial intervention in subordinates conflicts, which helped to represent various strategies identified in the literature in a single model. Managers’ power base was then related to their intervention strategies. Drawing upon Social Judgment Theory, anchoring of subordinates positions was studied as a moderating variable. Methodology – Thirty nine supervisors and their 165 subordinates from several organizations in Turkey filled out a questionnaire reporting power base of supervisor and their intervention strategy utilizing the Critical Incident Technique. Findings – Referent power of superior led to mediation in subordinates’ conflicts. However, mediation decreased while restructuring, arbitration, and educative strategies increased with increased anchoring of subordinates’ positions. These latter strategies mostly relied on reward power of manager. Subordinate satisfaction was highest with mediation and lowest when supervisors distanced themselves from the conflict. Limitations/Implications – The present study could only test the moderating effect of escalation as an anchoring variable. Future studies may look at the anchoring effect of whether the dispute is handled in public or in private, and whether the parties have a competing versus collaborative or compromising styles. Practical implications – Training of managers in mediation may be essential in cultures where they play a focal role in handling subordinates conflicts. Such training may have to take into account their broader influence strategies and use of power. Originality/Value – An influence perspective is useful in integrating the vast array of managerial intervention strategies in the literature. Furthermore, the anchoring effect provides a theoretical explanation for managers’ use of more forceful intervention with less cooperative subordinates

    Bases of Power and Conflict Intervention Strategy: A Study on Turkish Managers

    Get PDF
    Purpose – This study developed an influence perspective for managerial intervention in subordinates conflicts, which helped to represent various strategies identified in the literature in a single model. Managers’ power base was then related to their intervention strategies. Drawing upon Social Judgment Theory, anchoring of subordinates positions was studied as a moderating variable. Methodology – Thirty nine supervisors and their 165 subordinates from several organizations in Turkey filled out a questionnaire reporting power base of supervisor and their intervention strategy utilizing the Critical Incident Technique. Findings – Referent power of superior led to mediation in subordinates’ conflicts. However, mediation decreased while restructuring, arbitration, and educative strategies increased with increased anchoring of subordinates’ positions. These latter strategies mostly relied on reward power of manager. Subordinate satisfaction was highest with mediation and lowest when supervisors distanced themselves from the conflict. Limitations/Implications – The present study could only test the moderating effect of escalation as an anchoring variable. Future studies may look at the anchoring effect of whether the dispute is handled in public or in private, and whether the parties have a competing versus collaborative or compromising styles. Practical implications – Training of managers in mediation may be essential in cultures where they play a focal role in handling subordinates conflicts. Such training may have to take into account their broader influence strategies and use of power. Originality/Value – An influence perspective is useful in integrating the vast array of managerial intervention strategies in the literature. Furthermore, the anchoring effect provides a theoretical explanation for managers’ use of more forceful intervention with less cooperative subordinates

    Definition of the Ethical Values and Ethics Codes for Turkish Midwifery: A Focused Group Study in Kocaeli

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    Background: The independent roles of midwives have not been properly defined, and midwifery ethical values and moral codes proper to Turkish culture have not been developed. The absence of legal regulations concerning midwifery has negatively affected midwifery in the process of professionalization. Objectives: The purpose of this study was to identify the professional values of midwifery in Turkey. Materials and Methods: A focus group was created with the participation of nine midwives working at two state hospitals and a university hospital that provide birth service for women in Kocaeli, which is the most important industrial city in Turkey. The opinions of the midwives on the characteristics that a good midwife should possess and the professional values that a good midwife should observe were collected via in-depth interviews. The interviews were recorded. A total of three meetings were held with the participants. Finally, the notes taken by the reporter during these interviews were rearranged, and the recordings were transcribed by the researchers. Results: The characteristics suggested by the participants were classified into three categories: professional, personal, and interpersonal. Professional competence, capacity to properly inform interested parties, trustworthiness, respect for individuals and human dignity, and empathy were the most commonly named characteristics. As for the professional values of midwifery, professional competence, trustworthiness, responsibility, maximum benefit, and protection of privacy were the most often identified. Midwives also reported that most of the difficulties they faced in the exercise of daily tasks concerned protecting the privacy of their patients as well as the integrity and prestige of the profession, achieving the maximum benefit and least harm for patients, and providing a just and equal service. Conclusions: The professional values were mentioned by participant midwives were similar to the values proposed by international professional organizations. But there were some differences perhaps due to cultural differences

    Assessment of cardiac ultrasonography in predicting outcome in adult cardiac arrest

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    Objective: A prospective follow-up study to evaluate the ability of cardiac ultrasonography performed by emergency physicians to predict resuscitation outcome in adult cardiac arrest patients. METHODS: Ultrasonographic examination of the subxiphoid cardiac area was made immediately on presentation to the emergency department with pulseless cardiac arrest. Sonographic cardiac activity was defined as any detected motion within the heart including the atria, ventricles or valves. Successful resuscitation was defined as any of: return of spontaneous circulation for ≥ 20 min; return of breathing; palpable pulse; measurable blood pressure. RESULTS: The study enrolled 149 patients over an 18-month period. The presence of sonographic cardiac activity at the beginning of resuscitation was significantly associated with a successful outcome (19/27 [70.4%] versus 55/122 [45.1%] patients without cardiac activity at the beginning of resuscitation). CONCLUSIONS: Ultrasono -graphic detection of cardiac activity may be useful in determining prognosis during cardiac arrest. Further studies are needed to elucidate the predictive value of ultrasonography in cardiac arrest patients. © 2012 Field House Publishing LLP

    A Hybrid Efficient PV-Battery Powered LED Lighting Scheme

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    As we all know now a day�s developing countries across Asia and Africa are hit with the serious energy crisis. So To fulfill the power demand people started looking towards renewable sources of energy such as solar and wind energy. In this paper fully controlled, flexible and self-adjusting LED lighting PV-Battery powered scheme using a pulse-width modulation (PWM) switching and controlled by a dual-loop error driven, time de-scaled, WM proportional-integral-derivative (WM-PID) control scheme for the PV-battery interfaced to the LED load. It decreases the amplitude of transient voltage and minimize inrush current for balancing common DC bus to the LED load. The new adjustable controller uses a directed dual-loop error-driven, error-time descaled controller for the PWM switching along with MOSFET/IGBT switches. The dual-action regulator uses error driven weighted modified (WM-PID) proportional-integral-derivative controller with quick response auxiliary derivative loops to achieve efficient control action
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