Cosmology on Compact and Stable Supergravity Background

We propose a cosmological model of D3-brane universe on compact and stable supergravity background of wrapped D7-branes in type IIB string theory previously argued to be dual to pure N=1 SU(N) gauge theory in four dimensions. A model universe of order Planck size near the UV boundary dynamically flows toward the IR with constant total energy density and accelerating expansion followed by smooth transition to decelerating expansion and collides with the wrapped D7-branes at the IR boundary. The model addresses the horizon and flatness problems with most of the expansion produced during the decelerating expansion phase. The inflationary scenario is used to generate sources of inhomogeneities in the cosmic microwave background radiation and seeds for large scale structure formation from quantum fluctuations which exit the Hubble radius early during the accelerating expansion phase and the model addresses the inhomogeneity problem with red tilt in the power spectrum. We propose that the kinetic energy of the model universe is converted to matter and radiation by the collision followed by formation of baryons that stabilizes the model universe against gravitational force from the background at a finite distance from the IR boundary with the wrapped D7-branes serving as sources of color. Friedmann evolution then takes over with a positive cosmological constant term coming from the remaining potential energy density which is interpreted as dark energy. The magnitude of dark energy density is smaller than the total energy density during the flow by a ratio of the scale factor when the model universe appears in the UV to the scale factor at the moment of collision and stays constant while the matter-radiation density falls during Friedmann expansion.Comment: 30 page

Corporate Acquisitions and Firm-level Uncertainty: Domestic versus Cross-Border Deals

This paper studies the impact of corporate acquisitions on the uncertainty faced by acquiring firms. We use data for UK public companies from 2004 to 2017 and employ a matching estimator combined with difference-in-differences to control for the endogenous selection of firms into acquiring status. Acquisitions exert a large and persistent effect on the volatility of stock returns of acquirers and is characterized by a pecking order: domestic takeovers lead to a reduction in the uncertainty faced by the acquirer, while cross-border acquisitions|particularly those involving target firms in emerging markets|engender a positive response in acquirers' volatility

Global Engagement and Returns Volatility

This paper finds that a greater reliance on foreign market sales increases the volatility of firms’ stock returns, using high-frequency data for publicly listed Japanese manufacturing firms over the period 2000–10. The two margins of global engagement we consider, namely, exports and sales via foreign affiliates (horizontal foreign direct investment), have both a positive and economically significant effect on firm-level volatility. We find, however, that increasing the intensity of sales through foreign affiliates has a stronger effect on volatility than a similar change in export intensity. We also uncover evidence consistent with the notion that firms’ need to use external finance to cover the substantial costs involved in reaching foreign consumers can be an important channel through which firms’ participation in international markets increases their exposure to economic uncertainty

Management system requirements for wireless systems beyond 3G

This paper presents a comprehensive description of various management system requirements for systems beyond 3G, which have been identified as a result of the Software Based Systems activities within the Mobile VCE Core 2 program. Specific requirements for systems beyond 3G are discussed and potential technologies to address them proposed. The analysis has been carried out from network, service and security viewpoints

Prevalence of Refractive Error and Visual Impairment among Rural School-Age Children of Goro District, Gurage Zone, Ethiopia

Background: Refractive error is one of the major causes of blindness and visual impairment in children; but community based studies are scarce especially in rural parts of Ethiopia. So, this study aims to assess the prevalence of refractive error and its magnitude as a cause of visual impairment among school-age children of rural community.Methods: This community-based cross-sectional descriptive study was conducted from March 1 to April 30, 2009 in rural villages of Goro district of Gurage Zone, found south west of Addis Ababa, the capital of Ethiopia. A multistage cluster sampling method was used with simple random selection of representative villages in the district. Chi-Square and t-tests were used in the data analysis.Results: A total of 570 school-age children (age 7-15) were evaluated, 54% boys and 46% girls. The prevalence of refractive error was 3.5% (myopia 2.6% and hyperopia 0.9%). Refractive error was the major cause of visual impairment accounting for 54% of all causes in the study group. No child was found wearing corrective spectacles during the study period.Conclusion: Refractive error was the commonest cause of visual impairment in children of the district, but no measures were taken to reduce the burden in the community. So, large scale community level screening for refractive error should be conducted and integrated with regular school eye screening programs. Effective strategies need to be devised to provide low cost corrective spectacles in the rural community.Keywords: Refractive error, visual acuity, visual impairment, childre

Determinants of under-five mortality in Gilgel Gibe Field Research Center, Southwest Ethiopia

Background: In developing countries like Ethiopia where there is no vital events registration system and laboratory diagnosis is lacking, causes of death in under-five children and its determinants could not be well known. The objective of this study was to investigate causes of death and its determinants in under-five children in Gilgel Gibe Field Research Center. Methods: A case-control study was conducted from December 12 to 27, 2005. Cases of under-five children who died between August 27, 2004 and September 22, 2005 and controls of alive children with the same age (+/-2 months) as cases were identified by a survey as the study population. Data were collected by trained enumerators using structured questionnaire adopted from World Health Organization (WHO). Causes of death were determined using the expert algorithm based on verbal autopsy data. Results: Neonatal and infant mortality rates were respectively 38 and 76.4 per 1000 live births. The two most common causes of death during neonatal period were prematurity (26.4%) and pneumonia (22.6%). Whereas the top causes of death in post-neonatal period were pneumonia (42%), malaria (37%) and acute diarrheal diseases (30%). Maternal education, practice and perception of mothers on the severity of illness and benefits of modern treatment were found to be independent predictor of child survival. Conclusion: Neonatal causes, pneumonia, malaria and diarrheal diseases were the major killers of under-five children in Ethiopia. In this study, practice of mothers and perceived benefits on the modern treatment are identified as the key predictors of child survival which are amenable to future intervention.The Ethiopian Journal of Health Development Vol. 21 (2) 2007: pp. 117-12

Willingness to Pay For Insecticide-Treated Nets in Berehet District, Amhara Region, Northern Ethiopia: Implication of Social Marketing

Background: Understanding the feasibility of achieving widespread coverage with Insecticide- Treated Nets has to be preceded by learning how people value the Insecticide-Treated Nets and estimating the potential demand and willingness to pay so that sustainability of the intervention can be assured. The objective of this study was to determine willingness to pay for Insecticide-Treated Nets among households in Berehet District, Northern Ethiopia.Methods: A community-based cross-sectional study was conducted using both quantitative and qualitative methods in five randomly selected Kebeles from January-February 2012. Open ended contingent valuation technique with follow-up method was used. Qualitative data were collected through focus group discussions and observation methods. Binary logistic regression was used to determine the association between dependent and independent variables.Results: The average number of individuals per Insecticide-Treated Nets was 3.83 .Nearly 68.5% persons had willingness to buy Insecticide-Treated Nets if they have access to these Nets. The median maximum price a person is willingness to pay for blue rectangular Insecticide-Treated Net was 20 ETB. People had willingness to pay 30 ETB for blue and white conical insecticide-treated nets. Working on knowledge of malaria (OR=0.68, CI (0.47, 0.98; p<0.05), perceived benefit of Insecticide-Treated Nets (OR=0.28, CI (0.2-0.4; p<0.05), perceived susceptibility (OR=0.64(0.44-0.93; p<0.05) and perceived severity of malaria (OR=0.65(0.47-0.91, p<0.05) had significant association with a willingness to pay Insecticide-Treated Nets. Respondents who prefer kebele/place/ to buy Insecticide-Treated Net for rectangular shape had a significant association with a willingness to pay for Insecticide-Treated Nets(OR=1.92, CI= 1.07-3.92).Conclusion: Promotions, products, price and place had significant association with willingness to pay for Insecticide-Treated Nets. Designing a social marketing strategy helps ensure sustainable supply of Insecticide-Treated Nets and proper use of Insecticide-Treated Nets.Keywords: Willingness to pay, Insecticide-Treated Nets, Social marketing, Malari

Forest Carbon Stocks in Woody Plants of Mount Zequalla Monastery and It’s Variation along Altitudinal Gradient: Implication of Managing Forests for Climate Change Mitigation

Carbon sequestration through forestry has the potential to play a significant role in ameliorating global environmental problems such as atmospheric accumulation of GHG's and climate change.The present study was undertaken to estimate forest carbon stock along altitudinal gradient in Mount Zequalla Monastery forest. Systematic sampling methods were used to collect data from seventy 10 m x 20 m rectangular plots. The area was dominated by Juniperusprocera tree species. The mean carbon stock per hectare was 237.2, 47.6, 6.5 and 57.6 ton for above ground biomass, below ground biomass, litter biomass and soil respectively. The mean total carbon stock in Mount Zequalla Forest was 348.8 t ha-1. The statistical analysis for carbon stock variation in the different carbon pools through altitudinal gradient showed a significant variation with exception for soil organic carbon stock. The amount of carbon stock in above and below ground biomass showed increasing pattern with increasing altitude whereas litter and soil organic carbon stocks showed decreasing pattern with increasing altitude.Overall this study points out Mount ZequallaMonastery forest has the potential to sequester plenty of CO2 with a considerable variation along altitude. Thus, it has paramount importance to give conservation priority to the forests to achieve climate change mitigation aspiration especially through forest carbon sequestration mechanism.Keywords: Carbon sequestration; Climate change; Altitudinal gradients; Mount Zequalla Monastery; Fores

A monitoring and evaluation framework to assess the performance of innovation platforms in the context of livestock value chains

Growing local and informal markets in Asia and Africa provide both challenges and opportunities for small holders. In developing countries, market failures often lead to suboptimal performance of the value chains and limited and inequitable participation of the poor. In recent years, innovation platforms have been promoted as mechanisms to stimulate and support multistakeholder collaboration in the context of research for development. They are recognized as having the potential to link value chain actors, and enhance communication and collaboration to overcome market failures. Despite the increased use of innovation platforms in research for development projects and programs, a monitoring and evaluation framework that encompasses the dynamic nature of innovation systems and value chains is not available. In this paper, the authors aim to develop a monitoring and evaluation framework for understanding and assessing the performance of innovation platforms in the context of pro-poor value chains, based on a discussion of various approaches