Relaxed disk packing

Motivated by biological questions, we study configurations of equal-sized disks in the Euclidean plane that neither pack nor cover. Measuring the quality by the probability that a random point lies in exactly one disk, we show that the regular hexagonal grid gives the maximum among lattice configurations

Design and Validation of quality improvement model of virtual learning in Farhangian University (mixed method)

Background and Objective:Higher education administrators are looking for ways to increase the number of courses and disciplines. While university budgets are steadily declining, they are forced to increase their distance learning courses to meet the growing needs of learners during budget constraints and recessions. Because this type of training does not require a classroom and the nees less full-time instructors. Over the past two decades, the issue of quality and excellence in universities and higher education institutions has become one of the most important issues in the field of higher education, and especially in the newly-establisehd Farhangian University. National evaluation systems are designed to evaluate teaching and learning programs in universities; and they have attracted atttention at the international level in higher education research, and interest in improving education, both nationally and internationally has increased. An increasing number of universities in Iran have started virtual education courses. Farhangian University has also provided a good platform for these trainings, but so far it has not been able to institutionalize a proper and comprehensive quality education. Therefore, due to the fact that the quantitative growth of virtual education is progressing, yet no improvement has been made in the quality of education, the researchers have taken a step towards responding to these challenges and filling the gap in research literature of the field. The purpose of this study is to design and validate a quality improvement virtual learning model using a mixed method. Methods: In the quantitative section, 608 students and professors were using stratified random sampling method. In the qualitative section, 18 professors were interviewed. The quantitative data was analyzed using descriptive methods and the grounded theory was used for the analysis of the qualitative data. The data analysis was based on open and pivoted coding. Finally, 14 main categories including quality improvement of virtual education at the University of Farhangian were investigated as strategies, background conditions, intervening conditions and outcomes. Findings: Results suggested that learning-educating activities and human actors had a positive and significant effect on improving quality and deployment strategies. Moreover, deployment strategies exerted a positive and significant impact on quality improvement. Background features also affected deployment strategies and quality improvement in a positive and significant way. The effect of deployment strategies and quality improvement on individual, organizational and transactional outcomes was also significant. Conclusion: Considering the position of Farhangian University in the present models, the fair distribution of knowledge and ignorance of instructors’ character and the positive effect of recruiting distinguished instructors are emphasized in the results section. In causes section, in discussing strategies centralized decision making is referred to; and in strategy section, development of trust making and culture building for virtual learning is referred to that includes using the experiences of other countries. In intervening conditions section, using Web 2 and Web 3, prior knowledge of learners and the combination of face-to-face and virtual education at Farhangian University are mentioned.   ===================================================================================== 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.  ====================================================================================

Direct and Indirect Selection for Forage Yield and Its Components in Sainfoin under Normal and Drought Stress Conditions

Selection based on indices is an effective method for breeding complex traits. To assess the efficiency of different selection methods, twenty one accessions of Sainfoin (Onobrychis viciifolia) were evaluated in two environments including drought stress and non-stress conditions according to a randomized complete block design with three replications in 2010. In this study, the selection indices of Smith-Hazel and Pesek-Baker were determined based on the percentage of dry matter yield, stem percent, plant height and number of stem per plant under both conditions. Also response to selection and relative selection efficiency were estimated for studied traits and dry matter yield. The highest estimated selection efficiency for genetically improvement of dry matter yield was obtained via selection for stem percent and number of stem per plant. Therefore, these traits can be used as an appropriate selection criterion for improvement of forage yield. In Smith-Hazel indices under normal environment plant height and under stress environment stem percent had the highest gain, while in Pesek-Baker index, under both moisture conditions percentage of dry matter yield had the highest gain. The results indicated that Smith-Hazel index 1 had the most selection efficiency and could be used in sainfoin breeding programs

Study of Genetic Diversity of grain yield-associated traits in Iranian and Exotic Safflower (Carthamus tinctorius) Germplasm

Safflower (Carthamus tinctorius L.) is cultivated in a wide range of geographical conditions in the world from Africa to Europe, India and China. Previous studies have shown that diversity in indigenous Iranian germplasm is limited for some traits therefore germplasm collections from other origins need to be considered. An experiment was conducted to evaluate agronomic and morphological traits of 100 Iranian and exotic safflower genotypes during 2011- 2012 at the Research Farm of Isfahan University of Technology, Isfahan, Iran, using a simple lattice design of 10 × 10. The results of analysis of variance showed that the differences among genotypes were highly significant (p < 0.01) for days to flowering, seed yield, plant height, number of heads per plant, number of seeds per head, 1000-seed weight, oil content and harvest index, indicating high variability in the studied germplasm. The highest and lowest heritabilities were observed for 1000-seed weight and seed yield, respectively, indicating that indirect improving for seed yield would be more beneficial. Genetic and phenotypic correlation coefficients showed that number of heads per plant, number of seeds per head and harvest index had significantly positive correlations with seed yield. The results of stepwise regression and path analysis showed that number of heads per plant, number of seeds per head and 1000-seed weight are the most important components of seed yield, among which, number of heads per plant had the greatest direct positive effect on seed yield. These traits could be used as criteria for indirect selection in safflower breeding programs. Factor analysis recognized three factors which explained 72.56 percent of total variations. These factors were defined as phenological, physiological source and efficiency factors. Cluster analysis based on the agronomic and morphological traits grouped the genotypes into three clusters. Iranian accessions were clearly discriminated from other genotypes and allocated in the group three. In conclusion, the results indicated that there was a broad genetic diversity among Iranian and foreign germplasm which can be exploited in breeding programs

Meta-analysis of the prevalence of depression among breast cancer survivors in Iran: an urgent need for community supportive care programs

OBJECTIVES: Depression, which is the most common comorbidity in breast cancer (BC) patients, has adverse effects on patients' quality of life, disease progress, and survival. METHODS: The protocol of this study was registered in PROSPERO (registration No. CRD42019121494). We electronically searched published studies through January 2019 with the aim of finding articles that investigated the prevalence of depression among BC survivors. Web of Science, Scopus, PubMed/MEDLINE, Science Direct, and Google Scholar were searched to obtain relevant published studies. This review included 14 cross-sectional and 4 cohort studies published from 2000 to 2018. We used a random-effects model to conduct the meta-analysis and generated a summary estimate for the pooled prevalence with 95 confidence intervals (CIs). A subgroup analysis was also conducted based on the depression assessment tool used and the study design. RESULTS: The total sample size of the studies contained 2,799 women with BC, including 1,228 women who were diagnosed with depression. The pooled prevalence of depression among Iranian women with BC was 46.83 (95 CI, 33.77 to 59.88) with significant heterogeneity (I-2 = 98.5; p<0.001). The prevalence of depression ranged from 14.00 (95 CI, 4.91 to 23.09) to 95.90 (95 CI, 91.97 to 99.83). The results of the subgroup analyses suggested that the depression assessment tool, year of publication, and study design were sources of heterogeneity. CONCLUSIONS: Our findings indicate a high prevalence of depression among BC patients, underscoring the urgent need for clinicians and health authorities to provide well-defined social and psychological supportive care programs for these patients

An overview on tumor treating fields (TTFields) technology as a new potential subsidiary biophysical treatment for COVID-19

COVID-19 pandemic situation has affected millions of people with tens of thousands of deaths worldwide. Despite all efforts for finding drugs or vaccines, the key role for the survival of patients is still related to the immune system. Therefore, improving the efficacy and the functionality of the immune system of COVID-19 patients is very crucial. The potential new, non-invasive, FDA-approved biophysical technology that could be considered in this regard is tumor treating fields (TTFields) based on an alternating electric field has great biological effects. TTFields have significant effects in improving the functionality of dendritic cell, and cytotoxic T-cells, and these cells have a major role in defense against viral infection. Hence, applying TTFields could help COVID-19 patients against infection. Additionally, TTFields can reduce viral genomic replication, by reducing the expressions of some of the vital members of DNA replication complex genes from the minichromosome maintenance family (MCMs). These genes not only are involved in DNA replication but it has also been proven that they have a crucial role in viral replication. Also, TTFields suppress the formation of the network of tunneling nanotubes (TNTs) which is knows as filamentous (F)-actin-rich tubular structures. TNTs have a critical role in promoting the spread of viruses through improving viral entry and acting as a protective agent for viral components from immune cells and even pharmaceuticals. Moreover, TTFields enhance autophagy which leads to apoptosis of virally infected cells. Thus, it can be speculated that using TTFields may prove to be a promising approach as a subsidiary treatment of COVID-19. Graphical abstract: [Figure not available: see fulltext.

The global and regional prevalence of hepatitis C and B co-infections among prisoners living with HIV: a systematic review and meta-analysis

BACKGROUND: Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are common among individuals with human immune deficiency virus (HIV) infection worldwide. In this study, we did a systematic review and meta-analysis of the published literature to estimate the global and regional prevalence of HCV, HBV and HIV coinfections among HIV-positive prisoners. METHODS: We searched PubMed via MEDLINE, Embase, the Cochrane Library, SCOPUS, and Web of science (ISI) to identify studies that reported the prevalence of HBV and HCV among prisoners living with HIV. We used an eight-item checklist for critically appraisal studies of prevalence/incidence of a health problem to assess the quality of publications in the included 48 cross-sectional and 4 cohort studies. We used random-effect models and meta-regression for the meta-analysis of the results of the included studies. RESULTS: The number of the included studies were 50 for HCV-HIV, and 23 for HBV-HIV co-infections. The pooled prevalence rates of the coinfections were 12% [95% confidence interval (CI) 9.0–16.0] for HBV-HIV and 62% (95% CI 53.0–71.0) for HCV-HIV. Among HIV-positive prisoners who reported drug injection, the prevalence of HBV increased to 15% (95% CI 5.0–23.0), and the HCV prevalence increased to 78% (95% CI 51.0–100). The prevalence of HBV-HIV coinfection among prisoners ranged from 3% in the East Mediterranean region to 27% in the American region. Also, the prevalence of HCV-HIV coinfections among prisoners ranged from 6% in Europe to 98% in the East Mediterranean regions. CONCLUSIONS: Our findings suggested that the high prevalence of HBV and HCV co-infection among HIV-positive prisoners, particularly among those with a history of drug injection, varies significantly across the globe. The results of Meta-regression analysis showed a sliding increase in the prevalence of the studied co-infections among prisoners over the past decades, rising a call for better screening and treatment programs targeting this high-risk population. To prevent the above coinfections among prisoners, aimed public health services (e.g. harm reduction via access to clean needles), human rights, equity, and ethics are to be seriously delivered or practiced in prisons. Protocol registration number: CRD42018115707 (in the PROSPERO international). GRAPHIC ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40249-021-00876-7