168 research outputs found

    Spectral splits of neutrinos as a BCS-BEC crossover type phenomenon

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    We show that the spectral split of a neutrino ensemble which initially consists of electron type neutrinos, is analogous to the BCS-BEC crossover already observed in ultra cold atomic gas experiments. Such a neutrino ensemble mimics the deleptonization burst of a core collapse supernova. Although these two phenomena belong to very different domains of physics, the propagation of neutrinos from highly interacting inner regions of the supernova to the vacuum is reminiscent of the evolution of Cooper pairs between weak and strong interaction regimes during the crossover. The Hamiltonians and the corresponding many-body states undergo very similar transformations if one replaces the pair quasispin of the latter with the neutrino isospin of the former.Comment: 9 pages, 5 figure

    Vortex lattices in dipolar two-component Bose-Einstein condensates

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    We consider a rapidly rotating two-component Bose-Einstein condensate with short-range s-wave interactions as well as dipolar coupling. We calculate the phase diagram of vortex lattice structures as a function of the intercomponent s-wave interaction and the strength of the dipolar interaction. We find that the long-range interactions cause new vortex lattice structures to be stable and lead to a richer phase diagram. Our results reduce to the previously found lattice structures for short-range interactions and single-component dipolar gases in the corresponding limits.Comment: 5 pages, 3 figure

    Assessment of the contents of electronic educational courses of the universities under SCORM standard

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    Background and Objective:The 21st century is the century of societies moving towards knowledge-based, knowledge sharing and transformation in the axes and basic concepts of life, including education in terms of quantity, quality and speed of presentation. The tendency of the world in recent decades to use technology in education due to the lack of traditional education to meet the needs of the education system in the curriculum and educational content, has attracted the attention of many thinkers to create methods and innovations in this field. Today, due to the increasing development of educational methods and dramatic advances in the field of information and communication technology, e-learning is one of the best strategies for achieving social justice in the field of higher education with the slogan "Quality higher education for all." E-learning has been developed in the world for a decade and a short time in Iran. The increasing demand for science, the limitations of traditional educational systems, and the evolution of methods of learning have led the world to methods in which time and place have lost their intrinsic value; Therefore, e-learning can be considered the most important factor in the scientific and cultural leap in the contemporary world. Considering the increasing popularity of using content production standards like SCORM in electronic education, the objective of this survey is evaluation of electronic education content courses in the universities under SCORM standard, from the viewpoint of students and professors. Methods: This study uses a descriptive applied survey-type methodology. Statistical population of the survey is professors and students of distance learning courses in the Shahid Beheshti University (case study) consisting of 230 students and professors. They were selected purposefully on the basis of Morgan and Krejcie table. Data collection tools were researcher-made questionnaires of students and professors. The alpha validity ratio for the students’ questionnaire was measured as0.77and for the professors’ questionnaire as 0.90. In order to analyze and evaluate data, descriptive statistics (mean value, standard deviation) and deductive statistics (one-sample t-test) were used. Findings: The survey findings showed there is a significant relationship between the mean value of accessibility, educational design, content organization, feedback and super-data in the electronic educational content courses in Shahid Beheshti University from the viewpoints of students and professors according to SCORM standards. It also showed that in their viewpoint, the mean value of SCORM standard factors in the electronic educational content courses of Shahid Beheshti University, according to this standard, is in an appropriate level. Conclusion: The present study, like any other research, has limitations such as using only one research tool, questionnaire and not using other tools, university and field of study limitations, difficulty in identifying experts in this field and identifying content production companies and virtual universities under SCORM standard. At the time of the research, the limited similar external background made it difficult for the researcher. Therefore, it is suggested that the present study be implemented in other universities with e-learning and in other fields of study to increase the power of generalizations; Based on the findings of the research, it is suggested that professors need to be taught how to standardize electronic content and to reduce costs, electronic content production in the university with the cooperation of professors and even students, and also to arrange the impact of e-learning standards SCORM should be further researched to provide accurate information on ways to increase the quality of education and welfare of universities with e-learning under the SCORM standard.   ===================================================================================== COPYRIGHTS  ©2019 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.  ====================================================================================

    Psychological Violence in the Health Care Settings in Iran: A Cross-Sectional Study

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    Background: Psychological violence is the most common form of workplace violence that can affect professional performance and job satisfaction of health care workers. Although several studies have been conducted in Iran, but there is no consensus regarding current status of such violence. Objectives: This study aimed to investigate the prevalence of psychological violence among healthcare workers employed at teaching hospitals in Iran. Patients and Methods: In this cross-sectional study, 5874 health professionals were selected using multistage random sampling. Data were collected using a self-administered questionnaire developed by the International Labor Organization, International Council of Nurses, World Health Organization, and Public Services International. Descriptive statistics were used to analyze the data. Results: It was found that 74.7% of the participants were subjected to psychological violence during the past 12 months. Totally, 64.5% of psychological violence was committed by patients’ families, but 50.9% of participants had not reported the violence, and 69.9% of them believed that reporting was useless. Conclusions: The results are indicative of high prevalence of psychological violence against healthcare workers. Considering non-reporting of violence in more than half of participants, use of an appropriate reporting system and providing training programs for health professionals in order to prevent and manage workplace violence are essential

    Cerebral Malaria in Mouse and Man

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    Cerebral malaria (CM) is an acute encephalopathy caused by the malaria parasite Plasmodium falciparum, which develops in a small minority of infected patients and is responsible for the majority of deaths in African children. Despite decades of research on CM, the pathogenic mechanisms are still relatively poorly defined. Nevertheless, many studies in recent years, using a combination of animal models, in vitro cell culture work, and human patients, provide significant insight into the pathologic mechanisms leading to CM. In this review, we summarize recent findings from mouse models and human studies on the pathogenesis of CM, understanding of which may enable development of novel therapeutic approaches

    The decrease in NKG2D+ Natural Killer cells in peripheral blood of patients with metastatic colorectal cancer

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    Background: Natural killer (NK) cells play important roles in the immune defense against tumors such as colorectal cancer. In humans, NKG2D is an activating immune receptor constitutively expressed in most cytotoxic lymphocytes including NK and CD8+ T cells. In this study, the expression of NKG2D molecule was investigated in peripheral blood NK cells from colorectal cancer patients and compared with healthy subjects. Methods: We studied 21 non-metastatic (low-grade), 17 non-metastatic (high-grade), 16 metastatic colorectal cancer patients, and 24 healthy controls. Peripheral blood samples were obtained to isolate peripheral blood mononuclear cells (PBMCs) and the percentage of peripheral blood NKG2D+CD3-CD56+ NK cells was analyzed by flow cytometry. The expression of NKG2D at mRNA level was also measured by real-time PCR in both, patients and control subjects. Results: The results showed a significant reduction in the percentage of NKG2D+NK cells as well as NKG2D mRNA expression in peripheral blood of metastatic colon cancer patients. Conclusion: This result suggests that decreased expression of activating NKG2D receptor in metastatic colorectal cancer might compromise NK cell function and allow tumor to evade immunity (Tab. 3, Fig. 4, Ref. 33). Text in PDF www.elis.sk

    Rapidly Rotating Fermions in an Anisotropic Trap

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    We consider a cold gas of non-interacting fermions in a two dimensional harmonic trap with two different trapping frequencies ωxωy\omega_x \leq \omega_y, and discuss the effect of rotation on the density profile. Depending on the rotation frequency Ω\Omega and the trap anisotropy ωy/ωx\omega_y/\omega_x, the density profile assumes two qualitatively different shapes. For small anisotropy (ωy/ωx1+4Ω2/ωx2\omega_y/\omega_x \ll \sqrt{1+4 \Omega^2/\omega_x^2}), the density consists of elliptical plateaus of constant density, corresponding to Landau levels and is well described by a two dimensional local density approximation. For large anisotropy (ωy/ωx1+4Ω2/ωx2\omega_y/\omega_x \gg \sqrt{1+4 \Omega^2/\omega_x^2}), the density profile is Gaussian in the strong confining direction and semicircular with prominent Friedel oscillations in the weak direction. In this regime, a one dimensional local density approximation is well suited to describe the system. The crossover between the two regimes is smooth where the step structure between the Landau level edges turn into Friedel oscillations. Increasing the temperature causes the step structure or the Friedel oscillations to wash out leaving a Boltzmann gas density profile.Comment: 14 pages, 7 figure

    Decline in peripheral blood NKG2D+CD3+CD56+ NKT cells in metastatic colorectal cancer patients

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    OBJECTIVE: Colorectal cancer (CRC) is one of the main causes of cancer deaths in the world. This cancer can be divided into non-metastatic and metastatic CRC stages. CD3+CD56+ NKT cell subsets are a minor T cell subset in peripheral blood and conduct the killing of tumor cells in direct manner. Little is obvious about levels and surface markers of these cells such as NKG2D in different cancers, especially in CRC. METHODS: We included 15 non-metastatic (low-grade), 11 non-metastatic (high-grade), 10 metastatic colorectal cancer patients and 18 healthy controls. The percentages of CD3+CD56+ NKT cells and NKG2D+CD56+ NKT cells from samples were analyzed by flow cytometry in peripheral blood mononuclear cells (PBMCs) of samples. RESULTS: We found that there was a significantly lower number of NKG2D+CD3+CD56+ cells in peripheral blood of patients with metastatic colorectal cancer compared with normal controls (77.53 ± 5.79 vs 90.74 ± 9.84 ; p < 0.01). CONCLUSION: The fact that frequency of NKG2D+CD56+ NKT cells was significantly lower in patients with metastatic colorectal cancer compared to healthy controls strengthens the hypothesis that NKT cells can play a substantial role in the protection against human colorectal cancer, and this opens up avenues for novel studies about elucidating the other aspects of tumor surveillance in CRC progression and immunotherapy

    Development and psychometric properties of a belief-based Physical Activity Questionnaire for Diabetic Patients (PAQ-DP)

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    <p>Abstract</p> <p>Background</p> <p>This study carried out to develop a scale for assessing diabetic patients' perceptions about physical activity and to test its psychometric properties (The Physical Activity Questionnaire for Diabetic Patients-PAQ-DP).</p> <p>Methods</p> <p>An item pool extracted from the Theory of Planned Behavior literature was generated. Then an expert panel evaluated the items by assessing content validity index and content validity ratio. Consequently exploratory factor analysis (EFA) was performed to indicate the scale constructs. In addition reliability analyses including internal consistency and test-retest analysis were carried out.</p> <p>Results</p> <p>In all a sample of 127 women with diabetes participated in the study. Twenty-two items were initially extracted from the literature. A six-factor solution (containing 19 items) emerged as a result of an exploratory factor analysis namely: instrumental attitude, subjective norm, perceived behavioral control, affective attitude, self-identity, and intention explaining 60.30% of the variance observed. Additional analyses indicated satisfactory results for internal consistency (Cronbach's alpha ranging from 0.54 to 0.8) and intraclass correlation coefficients (ranging from 0.40 to 0.92).</p> <p>Conclusions</p> <p>The Physical Activity Questionnaire for Diabetic Patients (PAQ-DP) is the first instrument that applies the Theory of Planned Behavior in its constructs. The findings indicated that the PAQ-DP is a reliable and valid measure for assessing physical activity perceptions and now is available and can be used in future studies.</p
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