142 research outputs found
On the Computational Complexity of Defining Sets
Suppose we have a family of sets. For every , a
set is a {\sf defining set} for if is the
only element of that contains as a subset. This concept has been
studied in numerous cases, such as vertex colorings, perfect matchings,
dominating sets, block designs, geodetics, orientations, and Latin squares.
In this paper, first, we propose the concept of a defining set of a logical
formula, and we prove that the computational complexity of such a problem is
-complete.
We also show that the computational complexity of the following problem about
the defining set of vertex colorings of graphs is -complete:
{\sc Instance:} A graph with a vertex coloring and an integer .
{\sc Question:} If be the set of all -colorings of
, then does have a defining set of size at most ?
Moreover, we study the computational complexity of some other variants of
this problem
Link between mindfulness and personality-related factors including empathy, theory of mind, openness, pro-social behaviour and suggestibility
This research investigated a potential linkage between mindfulness and personality characteristics such as openness to experience, empathy (empathic concern and theory of mind), prosocial behavior and suggestibility. A sample of 275 volunteers was recruited. A series of the research questionnaires and scales was employed to measure mindfulness, empathic concern, theory of mind (or perspective taking), prosocial behavior (or altruism) and suggestibility. Based on the quartile scores, participants were divided into two low (first quartile) and high (forth quartile) on mindfulness. Using a two-way MANOVA, the results showed that participants high on mindfulness exhibited increased theory of mind, prosocial behaviour and openness, in addition to decreased suggestibility. Neither main nor interaction effects were found for gender factor. Theoretical models in the field of social cognition will be discussed to explain how enhancement in cognitive functions due to mindfulness practice might alter personality characteristics and, in turn, influence socio-political behaviour
A closer look at the Emergence, Persistence and Disappearance of Emerging Diseases, Epidemics and Pandemics and the destiny of COVID-19
AbstractHumans have been long exposed to various infectious agents and have struggled or avoided encountering these factors based on their knowledge, awareness and experience at different times, in order to keep and promote their health. Although humans have overcome these factors and thus survived, whenever they encounter a new pathogenic agent not fully acquainted with its epidemiological behaviors, they have surprisingly faced with these factors. Accordingly, they were forced to surrender to all the resulting epidemic and pandemics owing to the lack of sufficient knowledge to fight them. The same fact is being experienced in COVID-19 pandemic, and human beings realized the lack of awareness of the actions and reactions of emerging factors, even in this day and age. They also acknowledged that the fight against this emerging agent and its consequences would be based on the experience of previous emerging agent as well as scientific and technological advances, and that they would win the battle. Here, we tried to investigate the casualties and correlations of the persistence and disappearance of emerging diseases, considering the experiences gained from the epidemiological behavior of emerging factors in the previous epidemics and pandemics. This goal has been followed in three consecutive sections: 1- Causes of emergence, 2- Stability and persistence and 3-The instability of many emerging diseases. We have concluded that the same is true for SARS, MERS, or coronaviruses that typically cause common cold.And at this time human will come to believe that natural and intentional biological hazards have always lurked in human health! As a final word, the awareness and readiness of human beings, maintaining environmental health and respecting the biological rights of all human beings are the purely all factors that will reduce the damage is. Keywords: Emerging, Reemerging, Disappearing, Epidemic, Pandemic, COVID-1
The relationship between health and religion from the standpoint of divine religions, the ancestors' medical sources and some literary works
For downloading the full-text of this article please click here.The relationship between health and religion has been repeatedly highlighted and emphasized in Avesta, the Holy book of Zoroaster, which has been cited and referred to by our theist ancestors thousands of years before the Bible, the Torah and the Quran. There has been noticed a number of points about the effects of prayers and spirituality on the treatment of patients in this book. For example, it is mentioned in Ardibehesht section of this book that...For downloading the full-text of this article please click here
Evaluating diagnostic accuracy of Ovarian instant frozen sections compared to delayed paraffin embedded permanent sections
Introduction: Frozen section is mainly performed to determine malignity, so it is of fundamental importance to evaluate the diagnostic accuracy of frozen sections performed for each group of tissues in order to reduce false diagnoses, unnecessary surgeries and following unwanted complications. This study is conducted to evaluate the diagnostic accuracy of frozen section performed on ovary tissue compared to permanent sections.
Materials and Methods: In this retrospective study, we evaluate frozen sections performed at Taleghani hospital pathology department in five years and their results were compared with permanent sections’ results to calculate sensitivity, specificity, negative predictive value and positive predictive value. In cases which results were discordant, we check for probable reasons.
Results: 83 species were evaluated from patients with a mean age of 42.9 years; the smallest was 19 and the oldest was 86 years old (Std. dev: 12.84). 75 cases of frozen sections were benign (90.4%) and 8 cases were malignant. 73 cases of permanent sections were benign (88%) and 10 cases were malignant (12%. Sensitivity, specificity, positive predictive value and negative predictive value rates were 66%, 100%, 100% and 96.55% respectively.
Conclusions: This study shows the importance of cooperation between pathologist and surgeons that they can prevent unnecessary surgeries. In our study the only cases of discordancy were borderline tumors and the diagnostic accuracy for all other species were perfect.
 
Prevalence and associated factors of overweight and obesity in reproductive-aged women in Rasht
Background and Aims: Obesity is one of the most common nutritional problems. Understanding the prevalence of overweight and obesity in women is essential to planning and prioritizing of health problems. The current study aimed to broaden our understanding of the prevalence and related factors of overweight and obesity in the women at ages of pregnancy in Rasht, Iran, in 2015.Materials and Methods: The present cross-sectional study was designed to investigate the prevalence of overweight and obesity in women aged 20 to 50 years living in Rasht. The multiple-stage sampling method was used to recruit the participants. All participants provided informed consent before entering the study. Body mass indexes of >30 kg/m2 and >25 kg/m2 were considered obese and overweight, respectively. The collected data were analyzed by descriptive statistics, chi-square test and correlation coefficients.Results: The mean age of participants in the study was 19.28 (SD= 6.99). About 2.9% and 24.8% of study participants were obese and overweight, respectively. Also, the relationship between prevalence of overweight, mobility status, age and income was statistically significant.Conclusion: Our study found that overweight and obesity is a major public health problem among women living in the region and, thus, more attention should be given to reproductive-aged women with increased obesity-related measures.Keywords: Prevalence, Overweight, Obesity, Women, Rash
An Experimental Investigation on the Effects of MQL Method on Grinding of Nickel Based Superalloy 738 (Inconel 738)
In this research, the usage possibility of minimum quantity lubrication in grinding super alloy Inconel 738 has been studied empirically to reach improved grinding and lubricating conditions. For reaching this purpose, based on Taguchi design of experiment method grinding variables were set in three levels and lubrications were set in six levels in order to compare conventional, dry and MQL methods. Studies have shown that in grinding this material by MQL method we can obtain the results very close to conventional mode in terms of force and surface roughness even having better surface quality. Results in MQL method by considering various oils with different viscosities show that Behzist 6046 and Canola herbal-based oil are the best replacement of conventional method in terms of force reduction and surface roughness. In fact, in the case of using the MQL method together with Behzist 6046 oil, a 50% reduction in the force output is observed and when using Behzist 6043 oil, there is only a 30% difference in the surface roughness obtained with the traditional method, which creates a better surface smoothness is visible. For all the 100 investigated modes, the results show that the optimal levels for the variables of advance speed, stone wheel speed and chipping depth are level 1, 2046 rpm and 5 microns, respectively. The specific vertical force can be predicted in more than 50% of the tests with the least error (about 20%)
Evaluation of association between polymorphisms in IL17A, IL17F and IL2 genes and chronic periodontal disease in some health care centers, north Tehran, 2015-2016
زمینه و اهداف: بیماریهای پریودنتال بخش عظیمی از بیماریهای دهانی مطرح برای سازمان بهداشت جهانی را شامل میشوند. مطالعات بسیاری نشان میدهد که ژنتیک نقش بسیار مهمی را برروی پیشرفت و شدت بیماریهای پریودنتال دارد. هدف این مطالعه مقایسه پلیمورفیسم ژن اینترلوکین 17 در بیماران مبتلا به پریودنتیت مزمن و افراد سالم در جمعیت ایرانی است.
مواد و روشﻫﺎ: 99 بیمار مبتلا به بیماری پریودنتال مزمن به همراه 75 نفر که از نظر پریودنتال سالم و یا مبتلا به ژنژیویت بودند، به وسیله پارامترهای کلینیکی (CAL , BOP , PD , GI) به عنوان جمعیت مورد مطالعه انتخاب و به 4 گروه تقسیم شدند. سپس از کل جمعیت 3 سیسی نمونه خون محیطی جمع آوری شد. پس از استخراج دی ان ای نمونههای جمع آوری شده در دمای ºC 80- منجمد شدند تا در نهایت تعیین ژنوتایپ توسط آبشار آنزیمی پلیمراز صورت گرفت. در کلیه مراحل انجام پژوهش، موازین اخلاقی مراعات گردید و رضایت آگاهانه از تمامی داوطلبین اخذ گردید.
یافتهها: بین پلیمورفیسم ژنوتایپهای مختلف ژن اینترلوکین 17 و پریودنتیت در جمعیت مورد مطالعه هیچگونه رابطه معناداری یافت نشد. همچنین در مقایسههای گروه بندی شده نیز اختلاف از نظر آماری معنادار نبود (P>0.05).
نتیجهگیری: در نهایت این مطالعه نشان داد که بین هیچ یک از ژنوتایپها و پریودنتیت مزمن در جمعیت ایرانی مورد بررسی، ارتباط وجود ندارد و برای یافتن نتایج قابل تعمیم به جمعیت ایرانی نیاز به مطالعات گستردهتری در آینده میباشد.Background and Aims: Periodontal diseases encompass a wide range of oral diseases in which world health organization concerns about them. The literature already includes several reports of genetics leading role in the development and intensity of periodontal diseases. The purpose of the present study was to investigate the association between IL-17A,F gene polymorphisms and susceptibility to chronic periodontitis in an Iranian population.Material and Methods: Totally 99 patients with chronic periodontal disease and 75 healthy periodontal cases or those with gingivitis were selected through clinical factors (GI, PD, BOP, CAL), as the studypopulation. They were then divided into four groups and 3mL peripheral blood sample were collected.Total DNA was extracted from samples and extracted DNA was stored at -80°C until genotyping and polymorphisms detection using restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR). Ethical issues were all considered. Informed consent was obtained from all volunteers before the study began.Results: Our data of IL-17 polymorphisms did not show a significant difference amongst study groups (p>0.05).Conclusion: We did not find statistically significant differences between study groups in Iranian population. Stratification analysis based on the severity of the chronic periodontitis indeed declared no significantdifference in relation to genotype distribution and allelic polymorphisms frequencies
Relationship between β-globin gene mutations and blood factors in Beta- Thalassemia carriers
Background: Iran, located in Eastern Mediterranean region, is one of the noteworthy centers for the prevalence of Beta-Thalassemia genetic disorder. The aim of this study was to investigate the relationship between Beta-globin gene mutations and blood factors in the carriers of Beta-Thalassemia. Materials and Methods: This descriptive study was to investigate the relationship between beta-globin gene mutations and the average volume of red blood cells in Beta-Thalassemia carriers referred to the health network. The study was conducted in Pakdasht and Varamin from 1997 to 2013. Ethical issues such as confidentiality of studied community were all considered. Results: In the present study, the relationship between some blood parameters of red blood cells, such as the mean volume of red blood cells (MCV), and the type of mutation in the beta-globin was analyzed. MCV was statistically related to the type of mutation (p=0.05). The mean and standard deviation values of MCV were 62.1 and 3.9, respectively.Conclusion: The amount of MCV can be used as a guide for quick access to genetic mutations in Beta-Thalassemia carrier couples referred to Genetic centers before and during the pregnancy. Keywords: Thalassemia, Genetic disease, Mutation, Blood factors, Iran Iran, located in Eastern Mediterranean region, is one of the noteworthy centers for the prevalence of Beta-Thalassemia genetic disorder. The aim of this study was to investigate the relationship between Beta-globin gene mutations and blood factors in the carriers of Beta-Thalassemia.Materials and Methods: This descriptive study was to investigate the relationship between beta-globin gene mutations and the average volume of red blood cells in Beta-Thalassemia carriers referred to the health network. The study was conducted in Pakdasht and Varamin from 1997 to 2013. Ethical issues such as confidentiality of studied community were all considered.Results: In the present study, the relationship between some blood parameters of red blood cells, such as the mean volume of red blood cells (MCV), and the type of mutation in the beta-globin was analyzed. MCV was statistically related to the type of mutation (p=0.05). The mean and standard deviation values of MCV were 62.1 and 3.9, respectively.Conclusion: The amount of MCV can be used as a guide for quick access to genetic mutations in Beta-Thalassemia carrier couples referred to Genetic centers before and during the pregnancy.Keywords: Thalassemia, Genetic disease, Mutation, Blood factors, Ira
Seasonal variation of Guillain-Barré syndrome in Iranian patients: a retrospective study
Background: It seems that the incidence of Guillain-Barré syndrome (GBS) has seasonal trends depending on weather as well as environmental and demographic factors such as upper respiratory tract infection (URI). The aim of this study was to evaluate seasonality of GBS and its electrophysiological subtypes.
Methods: In this cross-sectional study, the records of all admitted patients to all wards of Dr. Shariati Hospital from March 2009 to March 2019 according to ICD-10 codes for GBS and other similar neuropathies were investigated and 87 patients were registered based on fulfillment of Brighton criteria and symptom onset during the recent 4 weeks. Statistical analysis was performed by IBM SPSS version 20. A p-value < 0.05 was considered statistically significant.
Results: Most of the patients (63.2%, n=55) were men. The mean age of them was 49.1±19.2 years, and 41.3% (n=36) and 10.3% (n=9) participants had recent URI and gastrointestinal infection, respectively. The frequency of GBS in different seasons was 35.6% (n=31) patients in the winter, 27.6% (n=24) in the autumn, 19.6% (n=17) in the spring, and 17.2% (n=15) in the summer. The most frequent electrophysiological subtype was acute inflammatory demyelinating polyneuropathy (AIDP) in all seasons. The most common GBS disability score was 1.
Conclusion: The highest and the lowest occurrence was seen in the winter and summer, respectively. AIDP was the most common electrophysiological subtype in all seasons. More studies are suggested to evaluate other aspects of GBS on more details
- …