• Asian Pacific Journal of Cancer Prevention
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• v.16 no.12
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• pp.5081-5084
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• 2015

Background: Breast cancer is a malignant tumor that starts from cells of the breast and is seen mainly in women. It's the most common cancer in women worldwide and is a major threat to health. The purpose of this study was to fit a Cox proportional hazards model for prediction and determination of years of survival in Iranian patients. Materials and Methods: A total of 366 patients with breast cancer in the Cancer Research Center were included in the study. A Cox proportional hazard model was used with variables such as tumor grade, number of removed positive lymph nodes, human epidermal growth factor receptor 2 (HER2) expression and several other variables. Kaplan-Meier curves were plotted and multi-years of survival were evaluated. Results: The mean age of patients was 48.1 years. Consumption of fatty foods (p=0.033), recurrence (p<0.001), tumor grade (p=0.046) and age (p=0.017) were significant variables. The overall 1- year, 3-year and 5-year survival rates were found to be 93%, 75% and 52%. Conclusions: Use of covariates and the Cox proportional hazard model are effective in predicting the survival of individuals and this model distinguished 4 effective factors in the survival of patients.

• Korea Journal of Hospital Management
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• v.2 no.1
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• pp.137-161
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• 1997

This study purports to investigate the determinants of propensity to stay among nursing staff working at Korean hospitals. The independent variables contains three groups of determinants: environmental variables(job opportunity, spouse support, and parent support), psychological variables(met expectations, work involvement, positive affectivity, and negative affectivity), and structural variables(job autonomy, work unit control. routinization, supervisor support, coworker support, role ambiguity, role conflict, workload, resource inadequacy, distributive justice, promotional chances. job security, job hazards, and pay). The sample used in this study consisted of 329 nurses and 175 nurse aides from two university hospitals in Seoul and its surburbs. Data were collected with self-administered questionnaires and analyzed using path analysis. The results of this study indicate that: (1) the following variables, listed in order of size, have significant positive effects on propensity to stay among hospital nursing staff: job satisfaction, met expectations, supervisor support, job security, and positive affectivity, (2) the following variables, listed in order of size, have significant negative total effects on propensity to stay among hospital nursing staff: job opportunity, negative affectivity, and rutinization, (3) the model explains 44.2 percent of the variance in propensity to stay among nursing staff working at two university hospitals, and (4) managerial support for improving the job autonomy, distributive justice, and promotional opportunity for nurse aides are needed.

• Communications for Statistical Applications and Methods
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• v.11 no.2
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• pp.227-233
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• 2004

This paper presents our work on constructing a model that is intended to predict the probability of attrition at specified points in time among customers of an insurance company. There are some difficulties in building a data-based model because a data set may contain possibly censored observations. In an effort to avoid such kind of problem, we performed logistic regression over specified time intervals while using explanatory variables to construct the proposed model. Then, we developed a Cox-type regression model for estimating the probability of attrition over a specified period of time using time-dependent explanatory variables subject to changes in value over the course of the observations.

• The Korean Journal of Emergency Medical Services
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• v.6 no.1
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• pp.87-102
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• 2002

Injury has now replaced disease as the biggest single cause of death in children after their first birthday. Each day child dies from preventable, unintentional injury and the medical cost of these injury is increasing remarkably. It is necessary to develope injury prevention models to explain, predict, manage, evaluate and analyze the information about accident. The purpose of this paper is, firstly, to investigate parent's actions regarding safety measures at home and secondly, to identify the influencing factors of parents' safety behaviors. The selection of such factors is guided by the theoretical framework of the Pender's Health Promotion Model. Method ; The questionnaire was developed on the basis of other investigations, through pilot testing, peer review, and review by field health workers. The questionnaire was completed by 231 mothers of young children. Data was collected between April and May 2002. Variable Use of three different domains of safety behavior, safety habits, supervision and perception of safety devices, were listed. Mothers were self reported on internal locus of control, mother & child relationships, and marital intimacy. Also the elements of the Health Promotion Model: perceived benefit, barrier, threat, and self-efficacy, were surveyed. Results & discussion The results indicate that most parents take considerable action to reduce household hazards. The constructs derived from the Model were statistically significant differences for a small part of the variables on parental behavior to reduce hazards in the home, such as age, education, economic status, self-efficacy, perceived benefit, internal locus of control. Future studies ought to include social influences, such as expectations, perceived norms, knowledge, and child-related variables, relevant to parental safety measures in their home.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3243-3248
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• 2016

Background: Stomach cancer is the fourth most common cancer and the second leading cause of death from cancer in the world. In Iran, this type of cancer has high rates of incidence and mortality. This study aimed to assess the survival rate of patients with stomach cancer and its determinants in Kurdistan, a province with one of the highest incidence rates of stomach cancer in the country. Materials and Methods: We studied a total of 202 patients with stomach cancer who were admitted to Tohid Hospital in Sanandaj from 2009 to 2013. Using Kaplan-Meier nonparametric methods the survival rate of patients was calculated in terms of different levels of age at diagnosis, gender, education, residential area, occupation, underweight, and clinical variables including tumor histology, site of tumor, disease stage, and type of treatment. In addition, we compared the survival rates using the log-rank test. Finally, Cox proportional hazards regression was applied using Stata 12 and R 3.1.0 software. The significance level was set at 0.05. Results: The mean age at diagnosis was $64.7{\pm}12.0$ years. The survival rate of patients with stomach cancer was 43.9% and 7% at the first and the fifth year after diagnosis, respectively. The results of log-rank test showed significant relationships between survival and age at diagnosis, education, disease stage, type of treatment, and degree of being underweight (P<0.05). Moreover, according to the results of Cox proportional hazards regression model, the variables of education, disease stage, and type of treatment were associated with patient survival (P<0.05). Conclusions: The survival rate of patients with stomach cancer is low and the prognosis is very poor. Given the poor prognosis of the patients, it is critical to find ways for early diagnosis and facilitating timely access to effective treatment methods.

• Structural Engineering and Mechanics
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• v.75 no.3
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• pp.401-414
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• 2020

Unlike the existing truss models for shear and torsion analysis, in this study, the torsional capacities of reinforced concrete (RC) members were estimated by introducing multi-potential capacity criteria that considered the aggregate interlock, concrete crushing, and spalling of concrete cover. The smeared truss model based on the fixed-angle theory was utilized to obtain the torsional behavior of reinforced concrete member, and the multi-potential capacity criteria were then applied to draw the capacity of the member. In addition, to avoid any iterative calculation in the existing torsional behavior model, a simple strength model was suggested that considers key variables, such as the effective thickness of torsional member, principal stress angle, and strain effect that reduces the resistance of concrete due to large longitudinal tensile strain. The proposed multi-potential capacity concept and the simple strength model were verified by comparing with test results collected from the literature. The study found that the multi-potential capacity could estimate in a rational manner not only the torsional strength but also the failure mode of RC members subjected to torsional moment, by reflecting the reinforcing index in both transverse and longitudinal directions, as well as the sectional and material properties of RC members.

• Korea journal of population studies
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• v.35 no.2
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• pp.159-184
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• 2012

This study purports to analyze how individuals' labor market integration affect their transition to marriage. In doing so, I construct variables for job stability and continuity to represent labor market integration using labor force status and years of participation at the time of marriage and during the three years up to the point of marriage. In particular, I focus on differential effects of these labor market integration on the transition to marriage by cohorts: one for those who are likely to enter the labor market after the 1997 financial crisis and the other for those who are before the 1997 financial crisis. I used the Korean Labor and Income Panel Study and analyzed individuals aged above 18 in 2008. The main results are as follows. being currently employed and regular employment increases hazards of the first marriage for men but decreases them for women. long-term no-jobs decreases hazards of marriage for both women and men. long-term regular employment increases hazards of marriage for women but not for men at the statistically significant level. These effects vary by cohorts implying that recent economic and labor market instability deteriorated economic conditions for the youth making transitions to marriage.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.1
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• pp.95-103
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• 2015

Objectives: This study was conducted in order to better understand the conceptual model and Stoffenmanager nano module and apply it to the synthesis and packing processes of nanomaterials. Methods: Site visits were conducted to five nanomaterial production processes. Product and exposure variables were investigated in these workplaces. Hazard banding and exposure classification of the synthesis and packing processes of nanomaterials were conducted using documents and the website of Stoffenmanager Nano. Results: The five sites featured different products, packing tasks, ventilation and local exhaust, and others. The hazards for nano-nickel and copper were classified as E. The hazards for both fumed silica and indium tin oxide were classified as D. The hazard for spherical silica was classified as C. The exposure classes in the synthesis process of nanomaterials ranged from 2 through 4. The exposure classes in the packing process of nanomaterials ranged from 1 through 4. Conclusions: Application of Stoffenmanager nano to the synthesis and packing processes of nanomaterials helped to better understand the control level of the work environment and to suggest appropriate actions. The comparison of each process showed the effect of the production process and handling of solids and ventilation on exposure class.

• Structural Engineering and Mechanics
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• v.83 no.2
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• pp.179-193
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• 2022

The shear behaviour of reinforced concrete members has been studied over the past decades by various researchers, and it can be simulated by analysing shear panel elements which has been regarded as a basic element of reinforced concrete members subjected to in-plane biaxial stresses. Despite various experimental studies on shear panel element which have been conducted so far, there are still a lot of uncertainties related to what influencing factors govern the shear behaviour and affect failure mechanism in reinforced concrete members. To identify the uncertainties, a finite element analysis can be used, which enables to investigate the impact of specific variables such as the reinforcement ratio, the shear retention factor, and the material characteristics including aggregate interlock, tension stiffening, compressive softening, and shear behaviour at the crack surface. In this study, a non-linear probabilistic analysis was conducted on reinforced concrete panels using a finite element method optimized for reinforced concrete members and advanced sampling techniques so that probabilistic analysis can be performed effectively. Consequently, this study figures out what analysis methodology and input parameters have the most influence on shear behaviour of reinforced concrete panels.

• Safety and Health at Work
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• v.14 no.1
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• pp.1-9
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• 2023

Background: Firefighting involves exposure of firefighters to risks related to this activity, serious injuries, and occupational diseases are recorded. There are other consequences such as thermal and emotional stress. This systematic review is proposed in order to analyze the risks and consequences faced by these workers and thus provide elements to improve safety management systems in institutions. Method: A descriptive observational study of systematic literature review on the risks and consequences of exposure to firefighters' activity was proposed, and the information was analyzed and described based on the available data and according to the variables determined. Results: The studies showed data on mechanical, physical, chemical, psychosocial risks, workers' perception and resilience, and epidemiological data. Information related to firefighters' activity on falls and slips, exposure to noise, and high concentrations of carbon monoxide is detailed. In addition, the relationship between burnout, cognitive, and physical fatigue as adverse effects on health and performance is mentioned. Conclusions: Among the preventive measures, the use of personal protective equipment is suggested, incorporation in prevention programs of information on exposure to risk factors, as well as the implementation of models that can predict the perception of workers, additionally, the generation of management systems with safety climate models for fire departments.