Optimal designs for asymmetrical factorial paired comparison experiments

Three forms of a general null hypothesis Ho on the factorial parameters of a general asymmetrical factorial paired comparison experiment are considered. A class of partially balanced designscorresponding to each form of H₀ is constructed and the A,D and ioptimal design, minimizing the trace, determinant and largest eigenvalue of a defined covariance matrix of related maximumlikelihoodestimators, in that class is determined. Moreover, the optimal design in each class maximizes the noncentrality parameter λ² of the asymptotic noncentral chi-square distribution of the likelihood ratiostatistic -2 log λ for testing H_o under defined local alternatives. These results apply directly to symmetrical factorial paired comparison experiments as special casesExamples are given forillustrating applications of the developed results     

RigiScan data under long-term testosterone therapy: improving long-term blood circulation of penile arteries,penile length and girth,erectile function,and nocturnal penile tumescence and duration

Background: Late-onset hypogonadism (LOH) presents with low serum testosterone (TT) levels and sexual and nonsexual symptoms. Erectile dysfunction affects a man’s self-esteem and as a result partner relationship and quality of life.

Objectives: To investigate the andrological clinical profile outcomes of testosterone therapy (TTh) in men (n?=?88) with symptomatic LOH complaints and symptoms.

Main outcome measures: Erectile function was assessed using the International Index of Erectile Function-5 questionnaire at baseline and at 6 and 12 months of TTh. In addition, penile length was measured at baseline and 12 months. We also evaluated nocturnal penile tumescence (NPT, using RigiScan) and blood flow of cavernous arteries (penile Doppler ultrasonography) at baseline and 12 months of TT.

Materials and methods: Eighty-eight LOH men (M_age 51.1 years) with erectile dysfunction, all with serum TT?<10.4?nmol/L before TTh. Patients received intramuscular long-acting testosterone undecanoate for 12 months.

Results: Following TTh, in all patients, serum TT levels were restored within 3 months to normal levels. Compared with baseline values, erectile function significantly improved at 6 (mean score increase 1.95) and 12 months (mean score increase 2.16). No significant changes in penile length were observed. NPT significantly improved at 12 months in terms of both the frequency (mean increase 1.27 times) and duration of rigidity (mean increase 5.12?min). As regards the blood flow of the cavernous arteries, we observed a significant improvement (decrease of 1.16?cm/s) and end diastolic velocity of the penile arteries.

Conclusion: TTh in men with LOH resulted in improvement of the erectile function, NPT, and to some extent the blood flow of the cavernous arteries.     

Culture,Structure, and the Refugee Experience in Somali Immigrant Family Transformation

This analysis suggests a theoretical refinement of migrant acculturation theories to deal specifically with refugee acculturation experiences. Using the case of family dynamics among Somali refugees in Minnesota, we find that the same factors that are theorized to affect voluntary migrants are also important for refugees. Specifically, the nature of exit from the sending society, the reception in a new location, and group characteristics all appear to be important. However, within the category of exit from the sending society, there are specific concerns that will be more relevant to refugees than to “voluntary” migrants. Specifically, the ongoing condition of the sending society and the effects of any transitions on transnational ties are critically important in the refugee context. We demonstrate how the societal upheaval that created the Somali refugee community also affected culture and connections within Somalia, and how this has an ongoing impact on the US Somali refugee community. We argue that it is valuable to refine the acculturation framework when considering refugees.     

Assessment of multidimensional poverty and effectiveness of microfinance-driven government and NGO projects in the rural Bangladesh

This paper has developed a multidimensional model usable in assessing economic, social, political and cultural dimensions of poverty by utilizing primary data collected from 78 villages in Bangladesh using a participatory approach. Employing the developed model, a comparative analysis has been performed between microfinance-driven government (GO) and NGO (non-government organization) projects to explore their relative effectiveness in enhancing wellbeing of the poor in rural Bangladesh. It is observed that GO agencies are more effective in enhancing ‘economic wellbeing’ of the poor, whereas NGOs are contributing more in the ‘social’ aspects of wellbeing. Findings also revealed that, as whole, GO agencies perform 42% better than NGOs in improving living standards of the rural poor which contradicts with the existing literature of poverty reduction projects in developing countries.     

Simultaneity in the use of maternal-child health care and contraceptives: evidence from developing countries

This study examined the relationship between the use of maternal-child health (MCH) care and the use of contraceptives. The high correlation between the two may be due to the independent effect of one on the other or to an association of both with the same or similar background factors. We used structural equation models to examine the relationship between these two interventions. The data were derived from six Demographic and Health Surveys: Zimbabwe from Sub-Saharan Africa, Thailand from Asia, Egypt and Tunisia from North Africa, and Guatemala and Colombia from Latin America. The results show that in all six countries, the use of contraceptives and MCH care are significantly associated, independent of intervening factors; this finding suggests that families develop a joint demand for better-quality health and limited family size and translate these demands into action by using health services for mothers and for children and by voluntarily regulating fertility.     

Bangladesh

In Bangladesh the Population Control and Family Planning Division of the Ministry of Health and Population Control has decided to delegate increased financial and administrative powers to the officers of the family planning program at the district level and below. Currently, about 20,000 family planning workers and officials are at work in rural areas. The government believes that the success of the entire family planning program depends on the performance of workers in rural areas, because that is where about 90% of the population lives. Awareness of the need to improve statistical data in Bangladesh has been increasing, particularly in regard to the development of rural areas. An accurate statistical profile of rural Bangladesh is crucial to the formation, implementation and evaluation of rural development programs. A Seminar on Statistics for Rural Development will be held from June 18-20, 1980. The primary objectives of the Seminar are to make an exhaustive analysis of the current availability of statistics required for rural development programs and to consider methodological and operational improvements toward building up an adequate data base.     

Terrorism and the integration of Muslim immigrants

We study the effect that a series of Islamist terrorist attacks across Europe in 2004–2005 had on the integration of Muslim immigrants. Using unique panel data that oversamples immigrants in the Netherlands, we show that, shortly after the attacks, Muslim immigrants’ attitudes toward integration worsened significantly compared to those of non-Muslim immigrants, with no evidence of a negative trend in the attitudes of Muslims prior to the attacks. While, in particular, low-educated Muslims became more geographically segregated and unemployed after the attacks, high-educated Muslims were affected most negatively in terms of their perceived integration. This decline in perceived integration is associated with a higher intention to permanently re-migrate to the country of origin.     

Dependence between oil and commodities markets using time-varying Archimedean copulas and effectiveness of hedging strategies

The aim of this work is to study in a first step the dependence between oil and some commodity prices (cotton, rice, wheat, sucre, coffee, and silver) using copula theory, and then in a second step to determine the optimal hedging strategy for oil–commodity portfolio against the risk of negative variation in commodity markets prices. The model is implemented with an AR-GARCH model with innovations that follow t distribution for the marginal distribution and the extreme value copula for the joint distribution and parameters and dependence indices are re-estimated in each new day which allow taking into account nonlinear dependence, tails behavior, and their development over time. Various copula functions are used to model the dependence structure between oil and commodity markets. Empirical results show an increase in the dependence during the last 6 years. Volatility for commodity prices registered record levels in the same time with the increase in uncertainty. Optimal hedging ratio varies over time as a consequence of the change in the dependence structure.     

New confidence interval estimator of the signal-to-noise ratio based on asymptotic sampling distribution

In this paper, the asymptotic distribution of the signal-to-noise ratio (SNR) is derived and a new confidence interval for the SNR is introduced. An evaluation of the performance of the new interval compared to Sharma and Krishna (S–K) (1994) confidence interval for the SNR using Monte Carlo simulations is conducted. Data were randomly generated from normal, log-normal, χ², Gamma, and Weibull distributions. Simulations revealed that the performance of S–K interval is totally dependent on the amount of noise introduced and that it has a constant width for a given sample size. The S–K interval performs poorly in four of the distributions unless the SNR is around one. It is recommended against using the S–K interval for data from log-normal distribution even with SNR = 1. Unlike the S–K interval which does not account for skewness and kurtosis of the distribution, the new confidence interval for the SNR outperforms S–K for all five distributions discussed, especially when SNR?? 2. The proposed ranked set sampling (RSS) instead of simple random sampling (SRS) has improved the performance of both intervals as measured by coverage probability.