A simple bivariate count data regression model

This paper develops a simple bivariate count data regression model in which dependence between count variables is introduced by means of stochastically related unobserved heterogeneity components. Unlike existing commonly used bivariate models, we obtain a computationally simple closed form of the model with an unrestricted correlation pattern.

Tobacco Chewing, Smoking and Health Knowledge: Evidence from Bangladesh

Unlike the substance abuse studies in developed countries, tobacco consumption and its adverse effects in developing countries are poorly studied. The objective of this paper is to identify which factors influence individuals' decision to smoke cigarettes, chew tobacco and their knowledge about the health hazards of tobacco use. To allow for the potential correlation among smoking tobacco, chewing tobacco, and health knowledge, we estimate a trivariate probit regression model using household survey data from Bangladesh. For both chewing tobacco and smoking, the results show how the probabilities of uninformed tobacco user and uninformed nonuser vary across different demographic groups.Chewing tobacco

PATENTS, R&D AND LAG EFFECTS: EVIDENCE FROM FLEXIBLE METHODS FOR COUNT PANEL DATA ON MANUFACTURING FIRMS

Hausman, Hall and Griliches (1984) and Hall, Griliches and Hausman (1986) investigated whether there was a lag in the patent-R&D relationship for the U.S. manufacturing sector using 1970¿s data. They found that there was little evidence of anything but contemporaneous movement of patents and R&D. We reexamine this important issue employing new longitudinal patent data at the firm level for the U.S. manufacturing sector from 1982 to 1992. To address unique features of the data, we estimate various distributed lag and dynamic multiplicative panel count data models. The paper also develops a new class of count panel data models based on series expansion of the distribution of individual effects. The empirical analyses show that, although results are somewhat sensitive to different estimation methods, the contemporaneous relationship between patenting and R&D expenditures continues to be rather strong, accounting for over 60% of the total R&D elasticity. Regarding the lag structure of the patents-R&D relationship, we do find a significant lag in all empirical specifications. Moreover, the estimated lag effects are higher than have previously been found, suggesting that the contribution of R&D history to current patenting has increased from the 1970¿s to the 1980¿s.Innovative activity, Patents and R&D, Individual effects, count panel data methods.

The Knowledge Production Function for University Patenting

We estimate a knowledge production function for university patenting using an individual effects negative binomial model. We control for R&D expenditures, research field and the presence of a TTO office. We distinguish between three kinds of researchers who staff labs: faculty, postdoctoral students and PhD students. We also examine whether PhDs and postdoctoral scholars contribute equally to patent activity or whether there is a differential effect depending upon visa status. We find patent counts relate positively and significantly to the number of faculty, number of PhD students and number of postdocs. Our results also suggest that not all graduate students and postdocs contribute equally to patenting but that contribution is mediated by visa status. Working Paper 07-0

Differentials and determinants of men’s sexual behavior in Ethiopia

Introduction: Males’ involvement in sexual and reproductive health can bring greater impacts on the health of family members although it is an intricate issue and few explored in Ethiopia.Objective: The objective of this study was to investigate the sexual behaviour of Ethiopian men’s timing of entry into sexual activity, tendency to have multiple sexual partners in their life time and their motivation to take a VCT.Methods: The study was conducted based on the socio-economic and demographic data obtained from randomly selected 14,110 men in the age group 15 to 59 using multi-stage sampling of the 2011 Ethiopian DHS. The data were analysed using descriptive statistics, the Cox proportional hazards and binary logistic regression models.Results: Given the socio-cultural factors motivating men to experiment sex and prove sexual competence and capacity, 27.2% of the sampled respondents had premarital sex, 38.1% of them had multiple (i.e. two and more) sexual partners in their life time while only 42.5% have ever had voluntary counselling and testing. Multivariate analysis results show that the likelihood of having multiple sexual partners increased among older men; while the tendency to take VCT was significantly higher among men of marriageable age group (AOR = 1.18, P<0.05). Late entry into sexual activity (AHR= 0.90, P< 0.05) but higher likelihood of having multiple sexual partners (AOR = 1.40, P< 0.001) and taking VCT services (AOR = 3.01, P<0.001) were observed among men who attended secondary and higher education. Men with frequent access to media were also observed to indulge in sex early (AOR = 1.08, P<0.05) and have multiple life-time sexual partners (AOR = 1.35, P<0.001) with higher chances of taking VCT services (AOR =2.28, P<0.001).Conclusions: The study revealed that Ethiopian males have diversified sexual behaviour mainly governed by the socio-cultural and institutional settings of their living environment. Hence, there is a strong need to make use of formal and informal institutions in mediating male’s sexual behaviour in the country. [Ethiop. J. Health Dev. 2017;31(1):36-43]Key words: Male sexual behaviour, age at first sex, multiple sexual partners, VCT, Ethiopi

Review on Effect of Phosphorous Fertilizer and Its Availability on Growth and Development of Maize (Zea mays L.)

Maize (Zea mays L.) is an important cereal crop in the world. Low soil fertility is recognized as the major constraint to low maize production and productivity. Phosphorus (P) is an essential nutrient element for maize production. It plays an important part in many physiological processes that occur within a developing and maturing plant. It exists in the soil solution as an anion in various forms, mono-hydrogen phosphate (HPO4-2) or di-hydrogen phosphate (H2PO4–) depending on the soil pH. Phosphorus fertilization is a major input in crop production, as many soils lack sufficient P for effective crop production. Plants need phosphorus for growth, utilization of sugar and starch, photosynthesis, nucleus formation and cell division. An adequate supply of available P in soil is associated with increased root growth, which means roots can explore more soil for nutrients and moisture. A deficiency of P will slow overall plant growth and delay crop maturity. Phosphorus is primarily lost from farm fields through attachments to the sediment that erodes from the field, dissolved in the surface water runoff, or dissolved in leachates and carried through the soil profile. Nutrient management practices must be designed to supply required nutrients to the plant, taking into account the balance between crop demand and supply from the soil, development of P-efficient crops, and improving P-recycling efficiency in the future. Keywords: Phosphorus, Nutrient, Soil, Production and Maize. DOI: 10.7176/JEES/13-4-03 Publication date:June 30th 202

Validation of NP Fertilizer Rates on Medium Maturing Maize Varieties at Jimma, South Western Ethiopia

Maize is the primary staple crop in Ethiopia and plays an important role in the livelihood of the people of Ethiopia. However, its productivity is very low mainly due to low soil fertility and use approved maize varieties. After three years on farm field study of NP Fertilizer Rates on medium maturing maize varieties further evaluation and validation was conducted to determine optimum NP fertilizer rates and best medium maturing maize variety at Jimma Zone, Southwestern Ethiopia during 2019 main cropping season. The experiment had two N/P2O5; 92/69 and 115/86 kg ha-1 and two medium maturing maize varieties. Each treatment was assigned to each plot in Randomized Complete Block Design (RCBD) in factorial arrangement. Data on the yield and yield components were subjected to ANOVA using SAS version 9.3. The highest grain yield 7350 kg ha-1 and above ground biomass 14.53 ton ha-1 were recorded from BH547 with application of 115/86 kg ha-1 N/P2O5 fertilizer rate which was statistically at par with planting BH546 maize variety and application of 92/69 kg ha-1 N/P2O5 fertilizer rate with the highest net benefit 41,855 Ethiopian Birr ha-1. Therefore, a medium maturing maize variety BH546 with the application of 92/69 kg ha-1 N/P2O5 fertilizer rates can be taken as optimal and recommended for farmers under rain fed condition in Omonada woreda of Jimma zone and other similar humid agro-ecologies of the southwestern Ethiopia. Keywords: Maize variety, Nitrogen, Phosphorous and fertilizer rate DOI: 10.7176/JBAH/10-21-04 Publication date: November 30th 202

Determination of NP Fertilizer Rates and Plant Population Density on Yield and Yield Related Parameters of Quality Protein Maize (Zea mays L.) in Southwestern Ethiopia

Field studies were conducted in 2015 and 2016 under rain fed conditions in south western Ethiopia, Jimma zone to determine optimum plant population density and NP fertilizer on Maize. The experiment had four NP fertilizer rates; 69/52, 92/69, 115/86, and 138/104 N/P2O5 kg ha-1 and four plant population density; 44,444(75cm*30cm), 53,333(75cm*25cm), 66,666(75cm*20cm) and 88,888(75cm*15cm) plants per hectare. Each treatment was assigned to each plot in split plot design. Grain yield and above ground biomass significantly increased as plant populations and NP fertilizer rates increased. The number of ears per plant was significantly decreased as plant population density increased and increased with the increased rate of NP fertilizer. The greater lodging was recorded in 2015 cropping season when compared with that of 2016 cropping season. The highest grain yield 8752 kg ha-1 and above ground biomass 18.33 ton ha-1 were recorded from 138/104 N/P2O5 fertilizer. Regarding plant population density the highest grain yield 9401 kg ha-1 and above ground biomass 19.90 ton ha-1 were recorded from 88,888 plants ha-1 (75cm*15cm). The highest net benefit 30,669ETB ha-1 with highest MRR 164% was recorded from 115/86 N/P2O5 kg ha-1. Concerning plant population density the highest net benefit 36,705 ETB ha-1 with acceptable MRR 585% was obtained from 88,888 plants ha-1 (75*15cm). Therefore, plant population density 88,888 plants ha-1 (75*15cm a plant hill-1 or 75 x 30 cm two plants hill-1) with N/P2O5 fertilizer rate of 115/86 kg ha-1 can be advisable for farmers in the study area and adjacent woredas’ with similar agro-ecologies

Evaluation of Quality Protein Maize Variety under Integrated Uses of Different Fertilizer Sources in Jimma, South Western Ethiopia

Studies on the combined use of organic and inorganic fertilizers for maize are lacking at Jimma conditions. Therefore, a field experiment was conducted to determine the effect of integrated uses of organic with inorganic fertilizers sources on productivity of quality protein maize (QPM) variety BHQPY545 at Kersa, Omonada woreda and Jimma on station, Southwestern Ethiopia during 2016 and 2017 main cropping seasons and one year validation at Omonada woreda. The experiment involved factorial combinations of inorganic and organic fertilizer with negative control, 150 kg ha-1 NPSZnB+140 kg ha-1urea top dressed, recommended NP2O5 (92/69 kg ha-1), 100% compost, 25% compost + 75% recommended NP, 50% compost + 50% recommended NP, 75% compost + 25% recommended NP and 100% compost + 100% recommended NP fertilizer which was laid out in randomized complete block design (RCBD). The compost was added based on N equivalency of recommended fertilizer rate. Data on yield and yield components of maize were subjected to ANOVA using SAS version 9.3. The over location and year highest grain yield (8443 kg ha-1) and above ground biomass (21.52 t ha-1) was obtained from 100% compost + 100% recommended NP fertilizer. Partial budget analysis revealed 100% compost + 100% recommended NP fertilizer realized the maximum net return (39,718 ETB) with marginal rate of return (94%). From farmers decision point and current on farm input availability and technical feasibility and economic analysis, 92/69 kg ha-1 N/P205 fertilizer application taken as optimal fertilizer application and recommended for production of BHQPY545 in Jimma area and other similar humid agro-ecologies of southwestern Ethiopia. Keywords: Grain yield, inorganic fertilizer, organic fertilizer, recommended fertilizer rate, soil health. DOI: 10.7176/ALST/88-01 Publication date:July 31st 202

Correlates of High Risk Fertility Behaviour in Ethiopia: A Multilevel Analysis of the 2011 Ethiopian Demographic and Health Survey Data

High risk fertility is one of the main public health concerns in Ethiopia.  This study examines factors affecting high risk fertility (i.e. child birth at early (less than 18 years) and late (greater than 35 years), birth taking place within shorter birth interval (less than 24 months) and too many births (greater than four children)) based on last births taking place in the five years preceding the 2011 demographic and health survey data of Ethiopia collected among women in the age group 15–49 years. Percentage distribution was used to describe the data while a multilevel logistic regression model was fitted to identify the predictors of high risk fertility behaviour. The result shows that 58.7% of Ethiopian women were experiencing high risk fertility with considerable variation among the rural (62.1%) and urban (39.5%) residents. The likelihood of exposure to high risk fertility was significantly lower among educated women and those having high perception of HIV risk assessment but higher among that experiencing child loss and living in Somali region. The results generally indicate that high risk fertility behaviour in Ethiopia is partly explained by respondents’ educational attainment, survival status of children born to a woman, region of residence and neighbourhood factors that shape the perception of women about their exposure to risky situations. Awareness raising efforts should thus consider the socio-cultural contexts in which behavioural change occurs to tackle exposure to high risk fertility in addition to promoting the status of women to reduce their dependency on offspring at later ages. Keywords: High risk, fertility, child loss, Ethiopi