ESTIMATING THE RELIABILITY OF A NEW CONSUMER PRODUCT USING USER SURVEY DATA AND RELIABILITY TEST DATA

Because new products enter the market rapidly, estimating their reliability is challenging due to insufficient historical data. User survey data about similar devices (e.g., older versions of the new device) can be used as the prior information in a Bayesian analysis integrated with evidence in the form of product returns, reliability tests, and other reliability data sources to improve reliability estimation and test specification of the new product. User surveys are usually designed for purposes other than reliability estimation. Therefore, extracting reliability information from these surveys may be tricky or impossible. Even when possible, the extracted reliability information contains significant uncertainties. This dissertation introduces the critical elements of a reliability-informed user survey and offers methods for collecting them. A generic and flexible mathematical approach is then proposed. This approach uses the survey and reliability test data of similar products, for example, an older generation of the same product as prior knowledge. Then it combines them through a formal Bayesian analysis with the reliability test data to estimate the life distribution of the new product. The approach models continuous life distributions for products exposed to many damage-induced cycles. It proposes discrete life distribution models for products whose failures occur within several damaging cycles. The actual cycles for various applicable damaging stress profiles are converted into the equivalent (pseudo) cycles under a reference stress profile. When damage-induced cycles are estimated from user surveys, they may involve biases, as is the nature of most nontechnical users’ responses. This bias is minimized using an approach based on the Kullback-Leibler divergence method. The survey data and other evidence from similar products are then combined with the test data of the new product to estimate the parameters of the reliability model of the new product. The dissertation developed approaches to design reliability test specifications for a new product with unknown failure modes. The number of samples, stress levels, and the number of cycles for the accelerated life test are determined based on the manufacturer’s requirements, including the desired warranty time, the desired reliability with some confidence level at the warranty time, and the maximum number of samples. The actual use conditions (i.e., actual stress profiles and usage cycles) are grouped using clustering techniques. The centers of clusters are then used to design frequency-accelerated or stress-accelerated reliability tests. The application of the proposed reliability estimation approach and the test specification design approach is illustrated and used to validate the proposed algorithms using the simulated datasets for a hypothetical handheld electronic device with the failure mode of cracking caused by accidental drops. The proposed approaches can adequately estimate the reliability model and design test specifications for a wide range of consumer products. These approaches require reliability data about an existing product that is similar to the new product, however

Assessment of Uncivil Behaviors of Teachers and Students in Nursing and Midwifery faculties of Shahrekord

Introduction: The aim of this study was determining the uncivil behaviors of teachers and students, in nursery and midwifery schools of Shahrekord in 2016. Methods: This cross-sectional study used a questionnaire containing questions on uncivil behavior (disruptive and threatening). Participants were 20 teachers and 150 students of Nursing and Midwifery department of Shahrekord university of Medical Sciences from three fields (nursing, operating room and midwifery). The collected data was analyzed in the form of mean, standard deviation, percent and frequency and analytical tests such as Pearson, chi-square and Phi. Results: The average age of the fifty participants from each field of study was 54/4 ± 06/22 years. Of the 20 professors participating in the study, 90% were female and the average age was 38/9 ± 43/43 years. According to the findings, the participants thought the prevalence of uncivil behaviors was moderate. Professors found students more responsible for such behaviors (40% vs. 60%) while students believed both groups of participants were guilty. Conclusion: Although the frequency and severity of uncivil behaviors by students and teachers were not considerable, but due to the negative effects of such behaviors in learning and teaching environments, appropriate strategies to improve learning environments is highly necessary

Extra virgin olive oil in maternal diet increases osteogenic genes expression, but high amounts have deleterious effects on bones in mice offspring at adolescence

Objective(s): Maternal high-fat diet has been shown to have deleterious effects on the offspring bones. However, there is no study to assess the effects of type and amount of maternal dietary oil in an isocaloric diet, with focus on extra virgin olive oil (EVOO). The objective of the current study was to test the hypothesis that type of maternal dietary oil has more effects than its amount in an isocaloric diet during gestation and lactation on bone genes expression in offspring in adolescence. Materials and Methods: Virgin female C57BL/6 mice were impregnated and fed either the AIN 93G diet (received 16% of calories as soybean oil, as a control diet, or EVOO) or a high fat AIN 93G diet (received 45% of calories as soybean oil or EVOO) from the time of vaginal plug confirmation until offspring’s weaning. Results: After adjusting for the amount of oils, osteoprotegerin/ receptor activator of nuclear factor NF-κB ligand (OPG/RANK-L) and OPG expressions were 6.1- and 2.8-folds higher in offspring born to EVOO compared with soybean oil-fed mothers. OPG, beta-catenin, and OPG/RANK-L expression were 88%, 94%, and 70% lower in offspring born to the 45% oil-fed mothers compared with the 16% group. In contrast, peroxisome proliferator-activated receptor gamma-2 (PPARγ2) gene expression was higher in the 45% oil group, adjusted for the types of oil. Conclusion: Maternal EVOO consumption, but not soybean oil increased osteoblastic gene expression, and high amounts of both oils decreased osteoblastic and increased adipogenic genes expression in adolescent offspring

Optimal level of demand and supply public goods in the general equilibrium model with Lindahl tax

In the real world, there are commodities that although consumers are willing to pay for them, but they cannot obtain them by market. These goods are public goods that all people will benefit from their use, and about them so-called market fails. One of indicators for evaluation the performance of government is amount of production of public goods. In this regard, the optimal level of the production of public good that maximize households’ utility is very important. In this article, three sections are as follows; households, firms and government-monetary authorities, due to the limitations that each section is faced, each of them is looking to optimize its goals. The results of the optimization household utility function show the optimal level of public good demand that it is proportional to pay people as taxes. Also the results of production function of public good show the optimal level of supply of public goods and services. Compare the optimal amount of demand and supply of public good show that there is a huge gap between optimal levels

Applying User Surveys and Accelerated Tests Data to Estimate Reliability of New Consumer Products Using a Discrete Life Distribution Model

Assessing the reliability of consumer products that are subject to random discrete damage is critical during their design. Previous studies have approximated a continuous life distribution for consumer products by treating the occurrence (cycles) of accumulating damage as a continuous random variable. However, when the lifetime of a product is only a few damage cycles (e.g., ten drop cycles of a laptop), using a discrete lifetime distribution is more accurate. Using a discrete lifetime distribution is challenging because it contains a summation term with an unknown upper bound, which makes calculating its likelihood function cumbersome. This paper proposes a method to address this issue. First, the upper bound of the summation term is approximated through a gradient descent algorithm and the Maximum Likelihood Estimation method. Then, the upper bound is fixed, and the other parameters of the reliability model are estimated using Bayesian analysis. The paper presents a hypothetical case study that shows that using the discrete model leads to a more accurate estimation of product life when dealing with a small number of cycles

Effects of Diets Enriched in Omega-9 or Omega-6 Fatty Acids on Reproductive Process

Objective: Maternal type and amounts of dietary fatty acids affect on reproductive process in the mice. The present study investigated the effects of maternal supplementation with different amounts of omega-6 or omega-9 during pregnancy on the number of offspring, sex-ratio and duration of gestation. Materials and methods: Eight-week-old female C57BL/6 mice were randomly assigned into four dietary groups including low omega-6 (16%; LO6), low omega-9 (16%; LO9), high omega-6 (45%; HO6) and high omega-9 (45%; HO9) during gestation. Number of offspring, sex-ratio and duration of pregnancy were compared among four dietary groups. Results: There was significant difference between LO6 and HO6 (p < 0.0001), LO9 and HO9 (p < 0.0001) groups in total number of pups. The number of female and male offspring were significantly different between LO6 and LO9 (p = 0.009 and p = 0.001, respectively), LO9 and HO9 (p = 0.01 and p = 0.025) groups. Duration of pregnancy was significantly higher in low fat diet than high fat diet groups (< 0.001). Conclusion: High fat diet reduced number of pups, gestation duration and lead to early labor. Omega-9 fatty acids shifted sex of offspring to females

The Effects of the Preconception Endurance Exercise Training and Voluntary Exercise Activity during Pregnancy in C57BL/6 Mice on Lipid Profile of the Adult Offsprings

Abstract Background: The aim of this study was to determine the effect of preconception endurance exercise training with voluntary exercise activity during pregnancy in mother mice on lipid profile in adult offsprings. Materials and Methods: Twenty four C57BL/6 female mice were randomly divided into four subgroups: trained in preconception period and exercised during pregnancy (TE)(20.3±1.02g); trained in preconception periods but unexercised during pregnancy (TC)(21.58±0.4g); untrained in preconception periods but exercised during pregnancy (CE)(21.02±0.23g); untrained and unexercised (CC)(19.23±0.45g). Trained mice were subjected to a protocol of moderate endurance exercise training over a period of 4 weeks for 5 days before pregnancy. The fasting blood samples were collected from adult mice(8 weeks old) and serum levels of glucose and lipid profile were measured. Data were analyzed using two way ANOVA and Tukey’s post hoc test. Results: The Glucose test results in offspring showed that there was a significant interaction between group and sex and group main effect (p<0.001) Glucose levels of male offspring were significantly lower in TC and TE groups. Results on LDL also showed that the sex main effect was significant (p<0.001), and LDL levels of male born to TE and TC dams lower than in female offspring. Conclusion: Improving the mother's physical fitness by providing regular endurance training in the preconception period and maintaining it by exercise activty throughout pregnancy may have potential for eliciting positive changes in lipid profile of offspring, specially males

COVID-19 vaccination hesitancy is not all a conspiracy theory: A qualitative study from Iran

Background: The COVID-19 pandemic has burdened disastrous mortality and morbidity rates in society all over the world. While vaccination is one of the most effective immunization methods to control infectious diseases globally, some have avoided receiving the vaccine. We have aimed to investigate the reasons behind the hesitancy of vaccination among healthcare workers. Method: We performed ten semi-structured interviews with volunteered healthcare workers of Rasoul Akram hospital. Then each interview was anonymized, and Braun and Clarke's thematic analysis method was used to analyze the interviews. Results: Our data analysis revealed thirty-eight different codes as reasons for vaccination hesitancy among our interviewees.All these thirty-eight codes were grouped into ten sub-themes, and these sub-themes were further grouped into our four main themes:1. Fear of side effects, 2. Distrust, 3. Inefficiency, and 4. Non-necessity.Fear of side effects was the most frequent reason that interviewees mentioned. Also, Half of the interviewees mentioned distrust as a reason for COVID-19 vaccine hesitancy.At least once, all interviewees mentioned that they believed vaccination is inefficient.Some interviewees had beliefs and reasons that made them assume vaccination is simply not necessary. Conclusion: Fear of side effects, distrust, inefficiency, and non-necessity were the reasons that our participants refused to get vaccinated. Fear of side effects and distrust were the most common reasons that led to non-vaccination