Spate Irrigation Systems and Watershed Development in Eritrea: the case of Sheeb watershed

This paper describes the interactions of the Spate Irrigation System (SIS) in Eritrea with their upper watersheds, as a case study in Sheeb watershed. The spate irrigation practices, among others, include techniques to harvest runoff water, sediments, and nutrients. A strong relationship exists between the SIS in the lowlands of Eritrea and their upper watersheds. For example, the spate irrigation system in the lowlands of Sheeb area entirely depends for water, soils and nutrients on the resources of its upper watershed. Interventions of soil and water conservation practices in the upper watershed could reduce soil loss and sedimentation rates, in the long term. And, this in turn, lowers the quantity of sediments and nutrients harvested in spate irrigated fields of Sheeb. However, the runoff volumes may not be affected much (by such conservation measures) mainly because of the steep topography of the upper watershed with shallow soils, which induces more runoff than infiltration into the soils. It can be concluded that the lessons learned from the Sheeb watershed will be very useful for planning watershed development projects in other spate irrigated areas of Eritrea and possibly in other parts of the world where similar systems are practice

The Economic Lives of Black Immigrants: An Analysis of Wages, Homeownership, and Locational Attainment in the United States

Black immigrants are a quickly growing population who experience the effects of the intersection of race and national origin. Despite their significance, black immigrants are often overlooked because they are a small population compared to other immigrants. This dissertation consists of three separate studies sharing the objective of investigating black immigrant incorporation into the United States. Each chapter uses U.S. census and American Community Survey data to investigate an aspect of black immigrants\u27 wage and housing outcomes. Chapter one analyzes wage differences among blacks using linear regression models, which also control for selection into full-time employment. Chapter two also uses regression models to determine likelihood of homeownership and the values of homes once a household selects into homeownership. Chapter three measures the racial and socioeconomic segregation of black immigrants with the locational attainment model. I find in chapter 1 that, contrary to previous research, all black immigrants earn significantly lower wages than U.S.-born blacks. Yet, in chapter two I find that Caribbean immigrants are significantly more likely than U.S.-born blacks to own their homes and their homes are of equivalent or higher value than even U.S.-born whites at the national level. African-born blacks\u27 homeownership and house value increases over time, with house values reaching the levels of U.S.-born whites\u27. The high home values of foreign-born blacks indicate that black immigrants are able to gain access to neighborhoods that U.S.-born blacks are not. This is confirmed in chapter 3; I find that foreign-born blacks are less segregated from U.S.-born whites than U.S.-born blacks and live in neighborhoods where they are more likely to be exposed to those with at least a college degree or with an income to poverty ratio of three or more. In some metropolitan areas foreign-born blacks are more likely to live in these areas than even U.S.-born whites

Studies of nanoparticles from a group of uniform materials based on organic salts (GUMBOS)

Tesfai, Aaron, B.S., B.A., University of Missouri, Columbia, 2003 Doctor of Philosophy, Spring Commencement 2010 Major: Chemistry Studies of Nanoparticles from a Group of Uniform Materials Based on Organic Salts (GUMBOS) Dissertation directed by Professor Isiah M. Warner Pages in dissertation, 101. Words in abstract, 271. Ionic liquids (ILs) are defined as organic salts composed of ions with melting points at or below 100 °C. ILs have gained considerable attention because of their desirable properties such as low volatility, high thermal stability, and tunability. GUMBOS are an emergent class of organic salts, many of which are ionic liquids (ILs). However, some have melting points above 100 °C. The synthesis and characterization of nanoparticles derived from GUMBOS (nanoGUMBOS) is investigated in the first part of this dissertation. NanoGUMBOS are more advantageous than traditional nanoparticles because they possess the inherent desirable characteristics of ILs. In addition to the attractive properties of ILs, nanoGUMBOS can be easily tuned for potential applications by altering the constituent components. The second part of this dissertation investigates the synthesis and characterization of task specific nanoGUMBOS. More specifically, magnetic and fluorescent nanoparticles derived from GUMBOS were investigated in this section. The magnetic nanoGUMBOS were synthesized using an oil-in-water (o/w) emulsion preparation method. These nanoparticles are advantageous because they are uniformly magnetic due to the magnetic functional component built into the nanoparticle. Magnetic nanoGUMBOS synthesized in this section have potential applications in the biomedical field including drug delivery and hyperthermia cancer treatment. Fluorescent nanoGUMBOS were synthesized using different particle fabrication techniques: reprecipitation, o/w emulsion, and a hydrogel preparation method. These particles that are derived from fluorophore based cations are uniformly fluorescent because the GUMBOS synthesized contain the fluorophore. Both fluorescent and magnetic nanoGUMBOS offer many advantages as compared to traditional nanoparticles because their synthetic procedures are rapid, facile, and do not require laborious steps. In addition, these novel fluorescent nanoGUMBOS have potential applications in biomedical imaging

Continuous, Passive Liquid-Liquid Extraction and Emulsion Separation Within Microfluidic and Millifluidic Devices

Liquid-liquid extraction (LLE) is a method used to separate compounds based on their relative activity in two immiscible phases. By significantly reducing the scale of liquid-liquid extraction to the micro- and milli-fluidic levels, this separation process can bemade suitable for low volume, high value materials

Effect of Electron Beam Radiation on Microbial Inactivation, Radio-resistance and Nutritional Quality of Food

A non-thermal food processing method, Electron beam radiation efficiently inactivates foodborne pathogens. However, foodborne pathogens may develop resistance in response to sublethal stresses. Thus it is important to study the response of food microorganisms to e-beam and understand the mechanism underlying their survival abilities. The overall objective of this study was to examine the inactivation of foodborne microorganisms by electron beam radiation at sublethal levels, understand the radio-resistance development to this processing method and also to determine the effects of e-beam on chemical changes of nutrients in infant formula.;Four independent studies are included in this dissertation, in the first study, development of radio-resistant Salmonella Typhimurium in egg as a microbial response to e-beam at sublethal levels was investigated and the D10-value for S. Typhimurium was determined after repetitive processing with e-beam at sub-lethal doses. Survivors were enumerated on non-selective (TSA) and selective (XLD) media. Survivors from the highest dose were isolated and used in subsequent e-beam cycle. This process was repeated four times for a total of five e-beam cycles. D10-values for S. Typhimurium ATCC strain 14028 were 0.59+/-0.031 and 0.46+/-0.022 kGy on TSA and XLD, respectively. However, following the fifth e-beam cycle, the respective D10-values increased (P0.05) to develop radio-resistance faster on selective media, likely due to facilitated selection of radio-resistant cells within microbial population following each e-beam cycle. For all five e-beam cycles, S. Typhimurium had higher (P\u3c0.05) D10-values on non-selective media, indicating that sub-lethal injury followed by cellular repair and recovery are important for radio-resistance and inactivation of this microorganism.;To further investigate the radio resistance development of microorganisms to repetitive e-beam sublethal doses, in the second study DNA repair deficient E.coli DH5alpha that have mutations of recA and gyrA genes was used. The objective was to determine if repetitive processing with e-beam at sub-lethal doses increases D10-value of E. coli DH5alpha in ground beef. Five cycles of e-beam were conducted. D10-values increased (P\u3c0.05) significantly with each cycle. Following the third cycle D10-values were 0.32+/-0.006 and 0.32+/-0.002 kGy for survivors enumerated on non-selective and selective media, respectively; the fourth cycle 0.39+/-0.007 and 0.40+/-0.019 kGy; and the fifth cycle 0.46+/-0.006 and 0.46+/-0.020 kGy. The result of the study indicates E. coli DH5alpha increases radio-resistance to e-beam as a result of repetitive exposure to sub-lethal doses despite its DNA repair deficiency.;The third study investigated the role of recA and gyrA genes in E.coli DH5alpha that had become resistant to repetitive e-beam radiation in the previous study and its ability to repair the damage caused by e-beam. Genomic DNA from E.coli DH5alpha, radio-resistant A2 and A4 were extracted, and DNA fragments of the gyrA and recA genes containing the mutations were amplified, cloned and sequenced. E.coli DH5alpha and radio-resistant A2 and A4 were compared to a reference genome for identification of nucleotide polymorphisms, insertions, and deletions that may have contributed to its radio-resistance. Results of the study demonstrated that E.coli DH5alpha was able to reverse its mutation after sub lethal e-beam radiations. The study revealed that DNA repair deficient E. coli DH5alpha increased radio-resistance to e-beam as a result of repetitive exposure to sub-lethal doses despite its DNA repair deficiency due to its ability to reverse its mutation. Understanding the resistance development of microorganisms is important in designing a food process control and efficacy of the processing method.;The last study examined the effect of e-beam on chemical changes of nutrients in infant formula. Dehydrated infant milk formula was processed with e-beam at 0 (control) to 25 kGy. Amino acid, fatty acid, and mineral profiles (AAP, FAP, and MP, respectively), as well as protein degradation and lipid oxidation, were determined. Our results demonstrate proteins, lipids, and minerals in infant milk formula were stable when processed with e-beam up to 25 kGy

The role of ozone forcing on climate models

Thirteen coupled Atmospheric Oceanic Global Circulation Models (AOGCMs) and seven Chemistry Climate Models (CCMs) are compared to radiosonde and satellite observations to assess model performance and to study the connection between ozone forcing and model temperature trends during the last two decades. Overall, CCMs and AOGCMs that include time-varying ozone forcing agree reasonably well with observations in the lower stratosphere for both annual and seasonal averages, but models without time-varying ozone forcing (fixed) are statistically different from observations between ~ 150 hPa and 10 hPa. Both CCMs and those AOGCMs with time-varying ozone forcing capture the seasonality of the observed southern hemisphere extratropical lower stratospheric temperature trends. In the tropical lower stratosphere, only a few models show seasonal temperature trend variations that resemble the observations. In the middle troposphere (500 hPa), significant differences between models and observations were found, both in the tropics (during DJF and JJA) and in the southern hemisphere extratropics (during MAM and JJA). These differences are difficult to reconcile, although our analyses indicate that the inclusion of stratospheric ozone forcing may affect trends from the stratosphere down into the troposphere

Galileo and EGNOS as an asset for UTM safety and security

GAUSS (Galileo-EGNOS as an Asset for UTM Safety and Security) is a H2020 project1 that aims at designing and developing high performance positioning systems for drones within the U-Space framework focusing on UAS (Unmanned Aircraft System) VLL (Very Low Level) operations. The key element within GAUSS is the integration and exploitation of Galileo and EGNOS exceptional features in terms of accuracy, integrity and security, which will be key assets for the safety of current and future drone operations. More concretely, high accuracy, authentication, precise timing (among others) are key GNSS (Global Navigation Satellite System) enablers of future integrated drone operations under UTM (UAS Traffic Management) operations, which in Europe will be deployed under U-Space [1]. The U-Space concept helps control, manage and integrate all UAS in the VLL airspace to ensure the security and efficiency of UAS operations. GAUSS will enable not only safe, timely and efficient operations but also coordination among a higher number of RPAS (Remotely Piloted Aircraft System) in the air with the appropriate levels of security, as it will improve anti-jamming and anti-spoofing capabilities through a multi-frequency and multi-constellation approach and Galileo authentication operations. The GAUSS system will be validated with two field trials in two different UTM real scenarios (in-land and sea) with the operation of a minimum of four UTM coordinated UAS from different types (fixed and rotary wing), manoeuvrability and EASA (European Aviation Safety Agency) operational categories. The outcome of the project will consist of Galileo-EGNOS based technological solutions to enhance safety and security levels in both, current UAS and future UTM operations. Increased levels of efficiency, reliability, safety, and security in UAS operations are key enabling features to foster the EU UAS regulation, market development and full acceptance by the society.Peer ReviewedPostprint (author's final draft

The application and use of the partogram in evaluating the Saving Mothers programme in South Africa in 2002.

Thesis (M.PH.)-University of KwaZulu-Natal, 2004.The SA National Department of Health made maternal deaths notifiable in 1997. It also commissioned a National Committee on Confidential Enquiries into Maternal Deaths (NCCEMD) to confidentially investigate all maternal deaths, to write the "Saving Mothers Report" and to make recommendations based on the findings of the study. The Department of Health in 2003 commissioned an evaluation of the extent to which the 10 recommendations contained in the first "Saving Mother's Report" had been implemented. This rapid appraisal was carried out by Centre for Health and Social Studies (CHESS), University of Natal. A report 'The Progress with the Implementation of the Key Recommendations of the 1998 "Saving Mothers Report" on the Confidential Enquiry into Maternal Deaths in South Africa - A Rapid Appraisal," was published in 2003. The data collected on Recommendation 5 on the use of the obstetric partogram in 46 selected provincial hospitals in all the 9 provinces was only partially analysed in this report. This study reports on a secondary analysis of the 942 questionnaires that were completed on the use and application of the partogram in hospitals in South Africa. In the rapid appraisal experienced field workers evaluated the use of the partogram using a 36-point checklist. Provincial and national averages for each of these variables were calculated and hospitals were evaluated into how they performed according to these averages using Lot Quality Assurance Sampling methodologies. Using national and provincial averages, the hospitals in each province are compared with one another provincially and nationally. In addition, the application and use of partograms in areas and levels of hospitals are described. An attempt is made to show if there is relation between the number of deliveries and the recording of the partogram. The main findings were that, of all the provinces KwaZulu-Natal had the lowest number variables below the national average from the 36 variables used as a checklist. Eastern Cape and Limpopo had the highest number of variables below the national average. The hospital with the highest number below the national average is in the Eastern Cape. In the recording of the chart rural and level one hospitals are low in comparison with urban and level three hospitals. There was no relation in the recording of the chart and the number of deliveries

Stability of Carcinogenic Dimethylnitrosamine in Soil

Agronom