Classification of constraints using chain by chain method

We introduce "chain by chain" method for constructing the constraint structure of a system possessing both first and second class constraints. We show that the whole constraints can be classified into completely irreducible first or second class chains. We found appropriate redefinition of second class constraints to obtain a symplectic algebra among them.Comment: 23 pages, to appear in Int. J. Mod. Phys.

On the classification of consistent boundary conditions for f(R) \mathit{f}(\mathit{R})-Gravity

Using a completely covariant approach, we discuss the role of boundary conditions (BCs) and the corresponding Gibbons--Hawking--York (GHY) terms in $\mathit{f}(\mathit{R})$-gravity in arbitrary dimensions. We show that $f(\mathit{R})$-gravity, as a higher derivative theory, is not described by a degenerate Lagrangian, in its original form. Hence, without introducing additional variables, one can not obtain consistent BCs, even by adding the GHY terms (except for $f(\mathit{R})=R$). However, following the Ostrogradsky approach, we can introduce a scalar field in the framework of Brans-Dicke formalism to the system to have consistent BCs by considering appropriate GHY terms. In addition to the Dirichlet BC, the GHY terms for both Neumann and two types of mixed BCs are derived. We show the remarkable result that the $f(\mathit{R})$-gravity is itself compatible with one type of mixed BCs, in $D$ dimension, i.e. it doesn't require any GHY term. For each BC, we rewrite the GHY term in terms of Arnowit-Deser-Misner (ADM) variables.Comment: 21 page

Abelianization of First Class Constraints

We show that a given set of first class constraints becomes abelian if one maps each constraint to the surface of other constraints. There is no assumption that first class constraints satisfy a closed algebra. The explicit form of the projection map is obtained at least for irreducible first class constraints. Using this map we give a method to obtain gauge fixing conditions such that the set of abelian first class constraints and gauge fixing conditions satisfy the symplectic algebra.Comment: To appear in PL

Development of a pre-hospital emergencies protocol for the management of suicidal patients in Iran

Background: Suicide is a painful consequence of many psychiatric disorders and one of the most frequent psychiatric emergencies. Generally, pre-hospital technician is the first person in the treatment chain who attends the situation; hence, his/her sound clinical judgment and professional behavior can play an important role in preventing or stopping the suicide process. We tried to develop a concise, evidence-based, and step-by-step guide for dealing with a suicidal patient, which could be quickly reviewed by technicians before confronting a suicide situation. Method: We reviewed the literature for suicide management plans and protocols, to extract the evidence-based interventions and instructions for dealing with a suicide situation. Then, we discussed the extracted material in an expert panel, and developed the initial version of the protocol considering the local socio-cultural issues and available facilities. Subsequently, we reviewed the protocol in a meeting with pre-hospital technicians and emergency physicians, to receive their feedback and address any possible executive problems. Finally, we revised the protocol to its final version considering the feedbacks. Results: The basic principles of dealing with a suicidal patient are similar to other psychiatric emergencies and include: Patient Safety; Patient evaluation and diagnosis; and Patient (behavioral and pharmacological) management. However, specific considerations should be taken into account and special arrangements are necessary for suicidal patients. Whether the patient has attempted suicide or not, would guide the management to one of the two major paths. In addition, the needs of the family should be considered. Conclusion: A locally adapted protocol considering existing facilities in the emergency system and cultural issues in Iranian society is provided for pre-hospital emergency technicians. © 2021, The Author(s)

Practical difficulties in estimating the prevalence of primary infertility in Iran

Background: According to the World Health Organization (WHO)'s clinical, epidemiological and demographic definitions, infertility is an inability to become pregnant within one, two or five years of exposure to pregnancy, respectively. Inconsistent infertility-related definitions and various methodological approaches make it difficult to compare quantitative data in this regard and consequently, have negatively influenced estimating the prevalence of infertility. The present study reviewed the results of a large population-based survey on how the clinical, epidemiological and demographic definitions of infertility produce different results in terms of infertility prevalence in Iran and subsequently, compared the findings in order to find the right time of treatment-seeking by couples. Materials and Methods: This community-based, cross-sectional study was carried out by Avicenna Research Institute in the urban and rural parts of Iran between 2010 and 2011. Using cluster sampling, the reproductive history of 17,187 married women aged 20-40 years, was recorded. Totally, 1011 clusters were randomly selected according to post office codes, proportional to the population of the province. Descriptive and inferential statistical analysis of the data was carried out by SPSS statistical software. Results: The prevalence of primary infertility based on the WHO�s clinical, epidemiological and demographic definitions were 20.2, 12.8 and 9.2, respectively. In addition, secondary infertility rate was 4.9. Conclusion: Infertility estimates over a two-year exposure period made a 50 decrease in infertility rate; however, increasing exposure period to five years made no significant difference in infertility rate. The findings showed that most of the couples will get pregnant within two years of unprotected sexual intercourse and thus, need no treatment. Due to practical difficulties in estimating the prevalence of primary infertility, the reference limit for time to pregnancy, should be reconsidered and giving more time to younger women to become pregnant, seems reasonable. © 2019, Royan Institute (ACECR). All rights reserved

First line in psychiatric emergency: Pre-hospital emergency protocol for mental disorders in Iran

Introduction: This article is a report of designing a rapid and effective guide for paramedics who take care of patients in a pre-hospital setting to answer developing demands. Methods: The relevant literature was reviewed, and the topics were extracted. Then, the extracted items were discussed in an expert panel. Finally, items were discussed in a meeting including emergency technicians and emergency technical assistants to identify implementation problems. Results: Important topics for managing psychiatric patients were categorized at three levels: 1) Patient safety and security issues, 2) Patient status assessment and diagnosis, and 3) Patient management (medical, behavioral management, and referral to a treatment center). Discussion: This protocol can be a solution to improve emergency technician training. Such summarized protocols can be used for rapid review immediately before exposing a patient with an acute psychiatric condition. Due to specific cultural and different access to medicines in Iran, some issues are different. © 2020 The Author(s)

Correlation of interleukin 6 and transforming growth factor β1 with peripheral blood regulatory T cells in rheumatoid arthritis patients: a potential biomarker

Introduction: Proinflammatory cytokines and regulatory T cells (Tregs) are considered as important factors involved in autoimmunity development especially in rheumatoid arthritis (RA). Aim of the study: To investigate the frequency of peripheral blood Tregs and related cytokines in RA patients and to determine the possible correlation between Treg percentage and interleukin 6 (IL-6) and transforming growth factor β1 (TGF-β1) as indicators in assessment of Treg function and mechanisms preceding autoimmunity in RA. Material and methods: Thirty-seven Iranian RA patients with a moderate (3.2-5.1) disease activity score (DAS) and the same number of healthy age- and sex-matched individuals were enrolled. Frequency of peripheral blood Tregs (CD4+FoxP3+CD25high) was determined by flow cytometry. Serum levels of IL-6 and TGF-β1 and their expression levels in peripheral blood mononuclear cells (PBMCs) were evaluated by ELISA and Q-PCR, respectively. Results: Rheumatoid arthritis patients showed significantly lower peripheral blood Treg frequencies compared to healthy individuals. Additionally, Treg (%) showed a significant inverse correlation between serum concentrations of IL-6 and mRNA expression of PBMCs, whereas there was no significant correlation between Treg (%) and TGF-β1 levels. Conclusions: The current study revealed that Treg numbers were reduced in peripheral blood of RA patients. This reduction inversely correlated with IL-6 levels, which may lead to persistent autoimmune and inflammatory conditions in RA patients