Forecasting GDP Growth: Application of Autoregressive Integrated Moving Average Model

This paper uses Box-Jenkins approach to model and forecast real GDP growth in Ethiopia. Such an approach could easily provide forecast for key macroeconomic variables in limited data environment. Based on the approach, the paper estimates Autoregressive Integrated Moving Average ARIMA (1,1,1) model and forecasts real GDP growth. Both the in-sample fit and pseudo-out of sample forecasts show that the ARIMA model’s performance are good and better than other forecasts

Molecular Gas during the Post-Starburst Phase: Low Gas Fractions in Green Valley Seyfert Post-Starburst Galaxies

Post-starbursts (PSBs) are candidate for rapidly transitioning from star-bursting to quiescent galaxies. We study the molecular gas evolution of PSBs at z ~ 0.03 - 0.2. We undertook new CO (2-1) observations of 22 Seyfert PSBs candidates using the ARO Submillimeter Telescope. This sample complements previous samples of PSBs by including green valley PSBs with Seyfert-like emission, allowing us to analyze for the first time the molecular gas properties of 116 PSBs with a variety of AGN properties. The distribution of molecular gas to stellar mass fractions in PSBs is significantly different than normal star-forming galaxies in the COLD GASS survey. The combined samples of PSBs with Seyfert-like emission line ratios have a gas fraction distribution which is even more significantly different and is broader (~ 0.03-0.3). Most of them have lower gas fractions than normal star-forming galaxies. We find a highly significant correlation between the WISE 12 micron to 4.6 micron flux ratios and molecular gas fractions in both PSBs and normal galaxies. We detect molecular gas in 27% of our Seyfert PSBs. Taking into account the upper limits, the mean and the dispersion of the distribution of the gas fraction in our Seyfert PSB sample are much smaller (mean = 0.025, std dev. = 0.018) than previous samples of Seyfert PSBs or PSBs in general (mean ~ 0.1 - 0.2, std dev. ~ 0.1 - 0.2).Comment: 17 pages, 12 figures accepted in MNRA

Incidence and Predictors of Tuberculosis Among Adult PLWHA at Public Health Facilities of Hawassa City

Tuberculosis (TB) is the most frequently diagnosed opportunistic infection (OI) and disease in people living with HIV/AIDS (PLWHA), world-wide. This study aimed at determining the incidence and predictors of tuberculosis among people living with HIV.A Six year retrospective follow up study was conducted among adult PLHIV. The Cox proportional hazards model was used to identify predictors.A total of 554 patients were followed and produced 1830.3 person year of observation. One hundred sixty one new TB cases occurred during the follow up period. The overall incidence density of TB was 8.79 per 100 person-year (PY). It was high (148.71/100 PY) in the first year of enrolment. The cumulative proportion of TB free survival was 79% and 67% at the end of first and sixth years, respectively. Not having formal education(AHR=2.68, 95%CI: 1.41, 5.11 ), base line WHO clinical stage IV (AHR = 3.22, 95% CI=1.91-5.41), CD4 count <50 cell/ul (AHR=2.41, 95%CI=1.31, 4.42), Being bed redden (AHR= 2.89, 95%CI=1.72, 3.78), past TB history (AHR=1.65, 95% CI = 1.06,2.39), substance use (AHR=1.46, 95% CI=1.03,2.06) and being on pre ART (AHR=1.62, 95%CI:1.03-2.54 ) were independently predicted tuberculosis occurrence. Advanced WHO clinical stage, limited functional status, past TB history, addiction and low CD4 (<50cell/ul) count at enrollment were found to be the independent predictor of tuberculosis occurrence. Therefore early initiation of treatment and intensive follow up is important

Analyzing the determinants of farmers' choice of adaptation methods and perceptions of climate change in the Nile Basin of Ethiopia:

"This study identifies the major methods used by farmers to adapt to climate change in the Nile Basin of Ethiopia, the factors that affect their choice of method, and the barriers to adaptation. The methods identified include use of different crop varieties, tree planting, soil conservation, early and late planting, and irrigation. Results from the discrete choice model employed indicate that the level of education, gender, age, and wealth of the head of household; access to extension and credit; information on climate, social capital, agroecological settings, and temperature all influence farmers' choices. The main barriers include lack of information on adaptation methods and financial constraints. Moreover, the analysis reveals that age of the household head, wealth, information on climate change, social capital, and agroecological settings have significant effects on farmers' perceptions of climate change." from authors' abstractAdaptation, Perception on climate change, Agriculture, Climate change, Nile Basin of Ethiopia,

Citrus Production, Constraints and Management Practices in Ethiopia: The Case of Pseudocercospora Leaf and Fruit Spot Disease

Citrus is economically important fruit crop in Ethiopia. However, its production is seriously constrained by various diseases including Pseudocercospora leaf and fruit spot. Surveys were conducted between June 2012 and May 2013 in the main citrus production areas of the country to assess the spread of the disease, and to determine its incidence and severity. A total of forty-nine citrus orchards in twenty-eight districts were surveyed. Random sampling techniques were used for data collection. The results showed that the disease had prevailed and widely spread in the districts assessed in the wet humid areas of the south, southwest, northwest, and north central parts, but not in the low altitude drier areas of the central rift valley and the eastern region of the country. Accordingly, 63.3% of the orchards surveyed were infected with the disease. The overall mean incidences of the disease on leaves of sweet orange, mandarin, lemon and lime were 36.2, 21.5, 17.1 and 16.3% while disease severity ratings were 2.6, 2.3, 2.0 and 1.7, respectively. Similarly, the average incidences and severities on fruits were 63.8, 29.4, 18.0 and 16.7%, and 4.0, 3.0, 2.0 and 2.0, in the same order. However, disease incidences in the different orchards ranged from zero to 76.7% on leaves and from zero to 100% on fruits. Disease severity ratings also varied from one to five on both leaves and fruits. In general, citrus orchards in the south and southwest Ethiopia that are known to have high rainfall and humidity conditions were more severely affected by the disease than those in the northwest and north central parts of the country. In these areas, respondents indicated that many farmers completely abandoned their citrus trees due to this disease. The causative agent was also identified to be the fungus Pseudocercospora angolensis based on cultural and morphological characteristics, and pathogenicity tests of representative isolates obtained from infected leaf and fruit samples.Keywords: Citrus Leaf and fruit spot disease; Pseudocercospora angolensis; Ethiopi

From Starburst to Quiescence: Testing AGN feedback in Rapidly Quenching Post-Starburst Galaxies

Post-starbursts are galaxies in transition from the blue cloud to the red sequence. Although they are rare today, integrated over time they may be an important pathway to the red sequence. This work uses SDSS, GALEX, and WISE observations to identify the evolutionary sequence from starbursts to fully quenched post-starbursts in the narrow mass range $\log M(M_\odot) = 10.3-10.7$, and identifies "transiting" post-starbursts which are intermediate between these two populations. In this mass range, $\sim 0.3\%$ of galaxies are starbursts, $\sim 0.1\%$ are quenched post-starbursts, and $\sim 0.5\%$ are the transiting types in between. The transiting post-starbursts have stellar properties that are predicted for fast-quenching starbursts and morphological characteristics that are already typical of early-type galaxies. The AGN fraction, as estimated from optical line ratios, of these post-starbursts is about 3 times higher ($\gtrsim 36 \pm 8 \%$) than that of normal star-forming galaxies of the same mass, but there is a significant delay between the starburst phase and the peak of nuclear optical AGN activity (median age difference of $\gtrsim 200 \pm 100$ Myr), in agreement with previous studies. The time delay is inferred by comparing the broad-band near NUV-to-optical photometry with stellar population synthesis models. We also find that starbursts and post-starbursts are significantly more dust-obscured than normal star-forming galaxies in the same mass range. About $20\%$ of the starbursts and $15\%$ of the transiting post-starbursts can be classified as the "Dust-Obscured Galaxies" (DOGs), while only $0.8\%$ of normal galaxies are DOGs.The time delay between the starburst phase and AGN activity suggests that AGN do not play a primary role in the original quenching of starbursts but may be responsible for quenching later low-level star formation during the post-starburst phase.Comment: 30 pages, 18 figures,accepted to Ap