An insight into technology diffusion of tractor through Weibull growth model

Most of the technological innovation diffusion follows an S-shaped curve. But, in many practical situations this may not hold true. To this end, Weibull model was proposed to capture the diffusion of new technological innovation, which does not follow any specific pattern. Nonlinear growth models play a very important role in getting an insight into the underlying mechanism. These models are generally ‘mechanistic’ as the parameters have meaningful interpretation. The nonlinear method of estimation of parameters of Weibull model fails to converge. Taking this problem into consideration, we propose the use of a powerful technique of genetic algorithm for parameter estimation. The methodology is also validated by simulation study to check whether parameter estimates are closer to the real value. For illustration purpose, we model the tractor density time-series data of India as a whole and some major states of India. It is seen that fitted Weibull model is able to capture the technology diffusion process in a reasonable manner. Further, comparison is also made with Logistic and Gompertz model; and is found to perform better for the data sets under consideration.     

How does paid work affect who does the childcare? An analysis of the time use of Australian couples

This paper analyzes the effect of paid work by coupled parents of young children on the joint decisions to spend time engaged in childcare. We explore this using Australian Time-Use Survey data from 2006. We examine the effect of paid work in terms of the effect that total work time on a given day has on the amount of time spent on childcare; the allocation of time on activities across work and non-work days; and the effect of non-traditional work hours. The results show that mothers perform a large share of childcare, irrespective of their earning power or their partner’s availability to take on some of these tasks. The use of formal and informal childcare by others allows the mother to balance the competing demands of work and her own childcare; an effect that does not hold for fathers. These effects on childcare are also almost solely concentrated in the routine component of childcare (e.g. preparing meals, changing nappies), with each parent ‘protecting’ interactive childcare from the effect of both paid work and the relative availability of their partner to take on some of this childcare.     

Maximum Likelihood Estimators in Regression Models for Error‐prone Group Testing Data

Since Dorfman's seminal work on the subject, group testing has been widely adopted in epidemiological studies. In Dorfman's context of detecting syphilis, group testing entails pooling blood samples and testing the pools, as opposed to testing individual samples. A negative pool indicates all individuals in the pool free of syphilis antigen, whereas a positive pool suggests one or more individuals carry the antigen. With covariate information collected, researchers have considered regression models that allow one to estimate covariate‐adjusted disease probability. We study maximum likelihood estimators of covariate effects in these regression models when the group testing response is prone to error. We show that, when compared with inference drawn from individual testing data, inference based on group testing data can be more resilient to response misclassification in terms of bias and efficiency. We provide valuable guidance on designing the group composition to alleviate adverse effects of misclassification on statistical inference.     

Financial literacy and anxiety about life in old age: evidence from the USA

This study examines whether financial literacy can help to reduce anxiety about life in old age. We hypothesized that financially literate people are more able to earn income and accumulate assets, leading them to have a less anxious life in old age. On the other hand, less financially literate people rely more on social security to secure themselves in the old age as they are not able to accumulate sufficient assets. By using US survey data, we provide evidence that assets significantly reduce anxiety about life in old age only for people who are more financially literate. For less financially literate people, social security plays an important role in reducing anxiety about life in old age. Besides these, having a child and doing regular exercise also reduced anxiety for all respondents but marital status reduced anxiety in respondents over 40 years of age. The results of our study are robust to measurement of financial literacy and endogeneity problems.     

Formation and negotiation of identity: the case of the Kelantan Kampung Pasir Parit Peranakan Chinese

This article examines the formation and negotiation of identity among the Kampung Pasir Parit Peranakan Chinese, a unique sub-ethnic group of acculturated Chinese in Kelantan. Apart from their original Chinese identity, the Kampung Pasir Parit Peranakan Chinese have also adopted two additional identities, namely Malay and Siamese identities. Intermarriage with Siamese women in the early years is the main reason for the adoption of the Siamese identity, while regular social interactions with the local Malays have led to the adoption of a Malay identity. Thus, the identity of the Kampung Pasir Parit Peranakan Chinese comprises three contrasting components. Given such a complex identity, there is always a need for the Kampung Pasir Parit Peranakan Chinese to negotiate their identities to avoid any identity crisis. This negotiation of identity is at times demonstrated by the co-existence of identities and at times the clear demarcation of identities to fulfil different situational needs.     

Income Dependency on Non-timber Forest Products: An Empirical Evidence of the Indigenous People in Peninsular Malaysia

The indigenous people have been identified to be among the poorest and the most socioeconomically and culturally marginalized people all over the world. The main purpose of the paper is to explore the socioeconomic and demographic factors of indigenous people in Peninsular Malaysia in context of poverty and the role of income dependency of non-timber forest products (NTFP). The data were collected in 2014 and 2015 through primary and secondary sources. Partial least squares (PLS) method was used to analysis the data. PLS is a modeling technique that features multiple regression and principal component analysis. The study shows that still a large number of indigenous households is involved in the NTFP activities. But the communities are moving away from NTFP based income to cash-crop based income because of poor sustainable forest management and lack of forest property rights. However, NTFP have a significant role in the household income and contribute 24% of the average income. Moreover, the analysis shows that location is significant to the poverty. There should be a suitable sustainable forest management system which can teach these indigenous communities about proper way of NTFP gathering and given proper rights to forest land. Furthermore, education is not significant to indigenous people and there is a high rate of school dropout among them. The government should introduce a different education system for indigenous communities which will emphasize the importance of education to them.     

Can concern for the long-term care of older parents explain son preference at birth in India?

This study examines whether concern for the long-term care of older parents is the primary reason for son preference in India. Controlling for important socioeconomic factors that are believed to affect son preference, we find that concern for long-term care is the principal cause of son preference in India. Sons serve as the primary caregivers to elderly parents, while daughters are mostly engaged in caring for parents-in-law. This trend is more acute in rural than in urban areas. Our study also finds a strong implication of the filial relationship for the long-term care of elderly parents.     

A Child Labour Estimator: A Case of Bahawalpur Division

Social Indicators Research - Child labor is a distressing issue. There have been many attempts to estimate its magnitude. It is attempted here to develop an estimator to assess the magnitude of...     

孟加拉国人口分布研究

孟加拉国各省、区的人口分布存在着不均衡的特点,采取定量分析的方法,选取人口密度指数、胡佛指数和非均质性指数(index of concentration,Hoover’s index and in-homogeneity index)指标来分析孟加拉国人口分布现有的不平等程度和非均质性。研究结果表明,孟加拉国各省、区的人口集中都存在增加的趋势。同时,通过对斯皮尔曼等级相关系数(Spearman’s rank correlation coefficient)的计算,分析孟加拉国的各地区土地面积和人口密度的关系,发现二者之间存在着较大的负相关关系。     

Dealing with separation or near-to-separation in the model for multinomial response with application to childhood health seeking behavior data from a complex survey

Separation or monotone-likelihood can be observed in fitting process of a multinomial logistic model using maximum likelihood estimation (MLE) when sample size is small and/or one of the outcome categories is rare and/or there is one or more influential covariates, resulting in infinite or biased estimate of at least one regression coefficient of the model. This study investigated empirically to identify the optimal data condition to define both ‘separation’ and ‘near-to-separation’ (partial separation) and explored their consequences in MLE and provided a solution by applying a penalized likelihood approach, which has been proposed in the literature, by adding a Jeffreys prior-based penalty term to the original likelihood function to remove the first-order bias in the MLEs of the multinomial logit model via equivalent Poisson regression. Furthermore, the penalized estimating equation (PMLE) is extended to a weighted estimating equation allowing for survey-weight for analyzing data from a complex survey. The simulation study suggests that the PMLE outperforms the MLE by providing smaller amount of bias and mean squared of error and better coverage. The methods are applied to analyze data on choice of health facility for treatment of childhood diseases.