In recent years, there has been a strong interest in measuring the available bandwidth of network... more In recent years, there has been a strong interest in measuring the available bandwidth of network paths. Several methods and techniques have been proposed and various measurement tools have been developed and evaluated. However, there have been few comparative studies with regards to the actual performance of these tools. This paper presents a study of available bandwidth measurement techniques and
This report describes the adaptation of ultrasound-guided portocentesis technique in 15 adult hea... more This report describes the adaptation of ultrasound-guided portocentesis technique in 15 adult healthy camels (Camelus dromedarius) for portal vein blood collection. A second objective of the study was to compare haematological and biochemical constituents between portal vein blood (PB) and jugular vein blood (JB). The liver could be visualised in an area between the 11 th to 5 th intercostal space (ICS) on the right side. The portal vein (PV) was visible in the 11 th , 10 th and 9 th ICS. The centesis of the portal vein was successfully performed in all animals. The PV was round in cross sectional view; additionally, the PV was characterised by the typical stellate ramification at the portal fissure and therefore, it could be differentiated from other hepatic veins in this region. Compared to the wall of the PV, the walls of the hepatic vein appeared less echogenic. The majority of the measured haematological and biochemical parameters differed significantly between PB and JB.
Results and Discussion On histopathology, an adult-type granulosa cell tumour (GCT), a mixed germ... more Results and Discussion On histopathology, an adult-type granulosa cell tumour (GCT), a mixed germ cell tumour and a low-grade Sertoli cell tumour were diagnosed. The GCT (6.5 cm in diameter) was rounded and cystic, with a central hypoechogenic area. The ovarian tissue was entirely replaced by polygonal neoplastic cells (Fig. 1). The mixed germ cell tumour (15.3 cm in diameter) was hard and non-homogeneous. The ovary contained insular patterns of round, oval or spindle cells with myxomatous and hyalinised stroma. The stroma also contained osteoid tissue (Fig. 2). The ovarian low-grade Sertoli cell tumour (19 × 20 cm) was a solid, fairly round homogeneously echogenic structure. The ovarian tissue was completely replaced by aggregated tubules lined by Sertoli-type cells surrounded by abundant fibrous stroma (Fig. 3). The three types of tumours secreted relatively low levels of estradiol 17 and progesterone, whereas the level of inhibin-B was extremely high in the case of the Sertoli c...
The HIV/AIDS pandemic is a global crisis that affects the lives of millions of people. Although H... more The HIV/AIDS pandemic is a global crisis that affects the lives of millions of people. Although HIV counseling and testing (HCT) serves as the entry point for HIV prevention, treatment, and care, it remains a low priority in many settings. The aim of this study, therefore, was to assess the factors associated with HCT and their correlation with the sexual behavior of primary and secondary school teachers in Addis Ababa. A comparative cross-sectional study was conducted among primary and secondary school teachers in Addis Ababa, Ethiopia. A multistage sampling technique was used to select a representative sample of 1,136 teachers. HCT and sexual health behavior-related data were collected using a self-administered questionnaire. Binary logistic regression was employed to examine the relationships between HCT, sociodemographics, and risky sexual behavior-related variables. Of the 1,136 eligible study participants, 1,034 (91.0%) teachers completed the self-administered anonymous questi...
International Conference on Networking and Services (ICNS '07), 2007
This paper presents a new end-to-end available bandwidth measurement tool called IGMPS (Improved ... more This paper presents a new end-to-end available bandwidth measurement tool called IGMPS (Improved Gap Model using Packet Size parameter). IGMPS is a lightweight tool based on a new deterministic model of packet delays derived from the Probe Gap Model which uses packet pair technique for actively assessing bottleneck link characteristics. In a previous work that presented a detailed analysis of the capabilities and limitations of packet dispersion techniques, it is showed that probing packet size parameter has a considerable effect on the measurement accuracy. Based on this insight, the model implemented in IGMPS takes into account this parameter and introduce it in available bandwidth estimation formula. Through measurements on several network testbed configurations, we evaluated IGMPS in terms of accuracy, convergence time and intrusiveness and found that IGMPS provides available bandwidth estimates with high accuracy. We investigated the effect of several deciding factors on IGMPS measurement accuracy and found that when the probing packet size is equal or close enough to the cross traffic packet size, IGMPS estimates available bandwidth with a very high accuracy. The comparison of IGMPS to Spruce showed that our tool provides better quality of measurements and it clearly outperforms Spruce.
Hepatobiliary & pancreatic diseases international : HBPD INT, 2008
An intussusception is the invagination of one segment of the intestine into another. It is more c... more An intussusception is the invagination of one segment of the intestine into another. It is more common in children, but a rare clinical entity in adults, where the condition is almost always caused by tumors. A 51-year-old female presented with symptoms of gastric outlet obstruction associated with significant weight loss, but no jaundice. Routine hematological and biochemical investigation, including tumor markers, were normal. Abdominal ultrasound revealed duodenojejunal intussusception, and subsequent CT of the abdomen confirmed it. She underwent a laparotomy, which confirmed duodenojejunal intussusception. On reducing the intussusception and performing a duodenotomy, a periampullary mass was confirmed. Hence, she underwent a pylorus-preserving pancreaticoduodenectomy. Histology confirmed periampullary adenocarcinoma. Adult intussusceptions are mostly caused by tumors. Contrast CT is the investigation of choice, although ultrasound can be used. One should have a low threshold for...
In this paper, the design of a broadband 4x4 Butler matrix is presented for the first time on a t... more In this paper, the design of a broadband 4x4 Butler matrix is presented for the first time on a two-layer Substrate Integrated Waveguide (SIW) structure. The presence of path crossings in the matrix structure often imposes the use of extra OdB couplers - usually obtained using back to back pairs of 3dB couplers - for planar realizations. Specific designs that
2010 IEEE Antennas and Propagation Society International Symposium, 2010
ABSTRACT This paper addresses the design and analysis of a novel compact wideband phase shifter i... more ABSTRACT This paper addresses the design and analysis of a novel compact wideband phase shifter in SIW technology. Employing the recently developed low-loss two-level SIW transition, the proposed structure exploits the multi-layer possibility offered by the SIW technology offering a compact three layer design. Preliminary results have been reported by the authors in. This paper brings deeper understanding of the phase shifter design and performances through an equivalent circuit model with detailed results. The developed structure offers up to 66 % area reduction with respect to the analogous single layer, equal-length variable-width phase shifter reported in. Phase shifts of -45°, -90°, -135° and -180° are satisfied over 2 GHz bandwidth centered at 12.5 GHz with less than 5° peak-to-peak error. These phase shifters are particularly attractive for integration in more complex multi-layer systems as beam-forming networks.
2009 IEEE Antennas and Propagation Society International Symposium, 2009
ABSTRACT A novel structure for a compact waveguide-based CRLH phase shifter suitable for SIW tech... more ABSTRACT A novel structure for a compact waveguide-based CRLH phase shifter suitable for SIW technology has been developed. A simple design procedure is presented and verified by the simulation results based on the balanced CRLH TL equivalent circuit model. An eight-cell structure has been designed and optimized offering up to 270deg phase shift with a wideband performance over the frequency band (16-21 GHz). Future work includes further improvements in the phase shifter characteristics by modifying the waveguide width as well as the use of the developed structure in the design and fabrication of compact beam-forming matrices in SIW technology.
2008 IEEE Antennas and Propagation Society International Symposium, 2008
In this paper, two novel broadband SIW components are presented; both components are designed to ... more In this paper, two novel broadband SIW components are presented; both components are designed to operate in Ku band. The first is a novel broadband broad-wall parallel waveguide coupler with resonant slots and 90o phase shift. The second passive component is a novel low ...
Social capital is widely recognized as one of the five capitals that can be used to sustain livel... more Social capital is widely recognized as one of the five capitals that can be used to sustain livelihood, avert risk and vulnerability. This paper looks at the use of social capital as a risk mitigation device and to sustain livelihood and food security. In this research IFPRI panel data collected during 1996-1997 (pre-flood) and 1999-2000 (post-flood period) and field data
Journal of health, population, and nutrition, 2005
The paper describes a cross-sectional household survey conducted in randomly-selected villages in... more The paper describes a cross-sectional household survey conducted in randomly-selected villages in rural Ethiopia to assess strategies of households for coping with financial and time costs of illness. Results of the survey showed that the average monthly household health expenditure was 32.87 Birr (about 4.1 US dollars [1 US dollar = 8 Birr at the time of study]). In addition, the average time lost due to illness was 9.23 days for the sick and 7.38 days for their caretakers. Monetary price was a significant (p<0.05) deterrent from visiting health facilities among households with no land or house, the divorced or widowed, and those with annual income less than 500 Birr (62.5 US dollars). The main strategies to cope with the financial costs of illness were waiver privileges, selling household assets, and using savings. Division of labour among household members was used for compensating for the loss of working time due to sickness. The findings of the study indicate that financial ...
The researchers seek to find the relation between the number of training courses organized by JLI... more The researchers seek to find the relation between the number of training courses organized by JLIA and the number of participants and the relation between the number of participants and the type of training courses .In addition to that, the researchers also seek to investigate whether there was deterioration in the performance of JLIA in training and qualifying staff members.
In recent years, there has been a strong interest in measuring the available bandwidth of network... more In recent years, there has been a strong interest in measuring the available bandwidth of network paths. Several methods and techniques have been proposed and various measurement tools have been developed and evaluated. However, there have been few comparative studies with regards to the actual performance of these tools. This paper presents a study of available bandwidth measurement techniques and
This report describes the adaptation of ultrasound-guided portocentesis technique in 15 adult hea... more This report describes the adaptation of ultrasound-guided portocentesis technique in 15 adult healthy camels (Camelus dromedarius) for portal vein blood collection. A second objective of the study was to compare haematological and biochemical constituents between portal vein blood (PB) and jugular vein blood (JB). The liver could be visualised in an area between the 11 th to 5 th intercostal space (ICS) on the right side. The portal vein (PV) was visible in the 11 th , 10 th and 9 th ICS. The centesis of the portal vein was successfully performed in all animals. The PV was round in cross sectional view; additionally, the PV was characterised by the typical stellate ramification at the portal fissure and therefore, it could be differentiated from other hepatic veins in this region. Compared to the wall of the PV, the walls of the hepatic vein appeared less echogenic. The majority of the measured haematological and biochemical parameters differed significantly between PB and JB.
Results and Discussion On histopathology, an adult-type granulosa cell tumour (GCT), a mixed germ... more Results and Discussion On histopathology, an adult-type granulosa cell tumour (GCT), a mixed germ cell tumour and a low-grade Sertoli cell tumour were diagnosed. The GCT (6.5 cm in diameter) was rounded and cystic, with a central hypoechogenic area. The ovarian tissue was entirely replaced by polygonal neoplastic cells (Fig. 1). The mixed germ cell tumour (15.3 cm in diameter) was hard and non-homogeneous. The ovary contained insular patterns of round, oval or spindle cells with myxomatous and hyalinised stroma. The stroma also contained osteoid tissue (Fig. 2). The ovarian low-grade Sertoli cell tumour (19 × 20 cm) was a solid, fairly round homogeneously echogenic structure. The ovarian tissue was completely replaced by aggregated tubules lined by Sertoli-type cells surrounded by abundant fibrous stroma (Fig. 3). The three types of tumours secreted relatively low levels of estradiol 17 and progesterone, whereas the level of inhibin-B was extremely high in the case of the Sertoli c...
The HIV/AIDS pandemic is a global crisis that affects the lives of millions of people. Although H... more The HIV/AIDS pandemic is a global crisis that affects the lives of millions of people. Although HIV counseling and testing (HCT) serves as the entry point for HIV prevention, treatment, and care, it remains a low priority in many settings. The aim of this study, therefore, was to assess the factors associated with HCT and their correlation with the sexual behavior of primary and secondary school teachers in Addis Ababa. A comparative cross-sectional study was conducted among primary and secondary school teachers in Addis Ababa, Ethiopia. A multistage sampling technique was used to select a representative sample of 1,136 teachers. HCT and sexual health behavior-related data were collected using a self-administered questionnaire. Binary logistic regression was employed to examine the relationships between HCT, sociodemographics, and risky sexual behavior-related variables. Of the 1,136 eligible study participants, 1,034 (91.0%) teachers completed the self-administered anonymous questi...
International Conference on Networking and Services (ICNS '07), 2007
This paper presents a new end-to-end available bandwidth measurement tool called IGMPS (Improved ... more This paper presents a new end-to-end available bandwidth measurement tool called IGMPS (Improved Gap Model using Packet Size parameter). IGMPS is a lightweight tool based on a new deterministic model of packet delays derived from the Probe Gap Model which uses packet pair technique for actively assessing bottleneck link characteristics. In a previous work that presented a detailed analysis of the capabilities and limitations of packet dispersion techniques, it is showed that probing packet size parameter has a considerable effect on the measurement accuracy. Based on this insight, the model implemented in IGMPS takes into account this parameter and introduce it in available bandwidth estimation formula. Through measurements on several network testbed configurations, we evaluated IGMPS in terms of accuracy, convergence time and intrusiveness and found that IGMPS provides available bandwidth estimates with high accuracy. We investigated the effect of several deciding factors on IGMPS measurement accuracy and found that when the probing packet size is equal or close enough to the cross traffic packet size, IGMPS estimates available bandwidth with a very high accuracy. The comparison of IGMPS to Spruce showed that our tool provides better quality of measurements and it clearly outperforms Spruce.
Hepatobiliary & pancreatic diseases international : HBPD INT, 2008
An intussusception is the invagination of one segment of the intestine into another. It is more c... more An intussusception is the invagination of one segment of the intestine into another. It is more common in children, but a rare clinical entity in adults, where the condition is almost always caused by tumors. A 51-year-old female presented with symptoms of gastric outlet obstruction associated with significant weight loss, but no jaundice. Routine hematological and biochemical investigation, including tumor markers, were normal. Abdominal ultrasound revealed duodenojejunal intussusception, and subsequent CT of the abdomen confirmed it. She underwent a laparotomy, which confirmed duodenojejunal intussusception. On reducing the intussusception and performing a duodenotomy, a periampullary mass was confirmed. Hence, she underwent a pylorus-preserving pancreaticoduodenectomy. Histology confirmed periampullary adenocarcinoma. Adult intussusceptions are mostly caused by tumors. Contrast CT is the investigation of choice, although ultrasound can be used. One should have a low threshold for...
In this paper, the design of a broadband 4x4 Butler matrix is presented for the first time on a t... more In this paper, the design of a broadband 4x4 Butler matrix is presented for the first time on a two-layer Substrate Integrated Waveguide (SIW) structure. The presence of path crossings in the matrix structure often imposes the use of extra OdB couplers - usually obtained using back to back pairs of 3dB couplers - for planar realizations. Specific designs that
2010 IEEE Antennas and Propagation Society International Symposium, 2010
ABSTRACT This paper addresses the design and analysis of a novel compact wideband phase shifter i... more ABSTRACT This paper addresses the design and analysis of a novel compact wideband phase shifter in SIW technology. Employing the recently developed low-loss two-level SIW transition, the proposed structure exploits the multi-layer possibility offered by the SIW technology offering a compact three layer design. Preliminary results have been reported by the authors in. This paper brings deeper understanding of the phase shifter design and performances through an equivalent circuit model with detailed results. The developed structure offers up to 66 % area reduction with respect to the analogous single layer, equal-length variable-width phase shifter reported in. Phase shifts of -45°, -90°, -135° and -180° are satisfied over 2 GHz bandwidth centered at 12.5 GHz with less than 5° peak-to-peak error. These phase shifters are particularly attractive for integration in more complex multi-layer systems as beam-forming networks.
2009 IEEE Antennas and Propagation Society International Symposium, 2009
ABSTRACT A novel structure for a compact waveguide-based CRLH phase shifter suitable for SIW tech... more ABSTRACT A novel structure for a compact waveguide-based CRLH phase shifter suitable for SIW technology has been developed. A simple design procedure is presented and verified by the simulation results based on the balanced CRLH TL equivalent circuit model. An eight-cell structure has been designed and optimized offering up to 270deg phase shift with a wideband performance over the frequency band (16-21 GHz). Future work includes further improvements in the phase shifter characteristics by modifying the waveguide width as well as the use of the developed structure in the design and fabrication of compact beam-forming matrices in SIW technology.
2008 IEEE Antennas and Propagation Society International Symposium, 2008
In this paper, two novel broadband SIW components are presented; both components are designed to ... more In this paper, two novel broadband SIW components are presented; both components are designed to operate in Ku band. The first is a novel broadband broad-wall parallel waveguide coupler with resonant slots and 90o phase shift. The second passive component is a novel low ...
Social capital is widely recognized as one of the five capitals that can be used to sustain livel... more Social capital is widely recognized as one of the five capitals that can be used to sustain livelihood, avert risk and vulnerability. This paper looks at the use of social capital as a risk mitigation device and to sustain livelihood and food security. In this research IFPRI panel data collected during 1996-1997 (pre-flood) and 1999-2000 (post-flood period) and field data
Journal of health, population, and nutrition, 2005
The paper describes a cross-sectional household survey conducted in randomly-selected villages in... more The paper describes a cross-sectional household survey conducted in randomly-selected villages in rural Ethiopia to assess strategies of households for coping with financial and time costs of illness. Results of the survey showed that the average monthly household health expenditure was 32.87 Birr (about 4.1 US dollars [1 US dollar = 8 Birr at the time of study]). In addition, the average time lost due to illness was 9.23 days for the sick and 7.38 days for their caretakers. Monetary price was a significant (p<0.05) deterrent from visiting health facilities among households with no land or house, the divorced or widowed, and those with annual income less than 500 Birr (62.5 US dollars). The main strategies to cope with the financial costs of illness were waiver privileges, selling household assets, and using savings. Division of labour among household members was used for compensating for the loss of working time due to sickness. The findings of the study indicate that financial ...
The researchers seek to find the relation between the number of training courses organized by JLI... more The researchers seek to find the relation between the number of training courses organized by JLIA and the number of participants and the relation between the number of participants and the type of training courses .In addition to that, the researchers also seek to investigate whether there was deterioration in the performance of JLIA in training and qualifying staff members.
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Papers by Ahmed Ali