Frequency Analysis of Extreme Events and Developing Intensity Duration Frequency Curves: The Case of Jimma Town, Ethiopia

Frequency analysis of rainfall data enables to determine the future extreme events and developing IDF curves. The object of this study was to analysis the frequency of extreme events in precipitation, and develop Intensity, duration and frequency (IDF) curves. In this study 30 years daily rainfall data (1986-2015) from the National Meteorological Agency (NMA) was used. To develop IDF curves graphical and statistical methods were used. The result obtained indicates, the General Extreme Value (GEV) was the best fitted distribution function to the maximum annual daily observed data, at 95% of confidence interval. As the result of the computed sub daily rainfall data, the highest rainfall value for the duration of 24 hrs. and 100-year return period was 83.86 mm, whereas the lowest rainfall value was obtained for the duration of 10min and 2 year of return period was 13.34 mm. The correlation coefficient between the IDF curves developed from observed data and the Computed IDF curves was (R2=0.99). Keywords: - extreme events, frequency analysis, IDF curves, rainfall duration DOI: 10.7176/JNSR/12-21-02 Publication date: November 30th 202

Experimental and Simulation Study of a High Current 1D Silicon Nanowire Transistor Using Heavily Doped Channels

Silicon nanowires have numerous potential applications, including transistors, memories, photovoltaics, biosensors and qubits [1]. Fabricating a nanowire with the required characteristics for a specific application, however, poses some challenges. For example, a major challenge is that, as the transistors dimensions are reduced, it is difficult to maintain a low off-current (Ioff) whilst simultaneously maintaining a high on-current (Ion). Some sources of this parasitic leakage current include quantum mechanical tunnelling, short channel effects and statistical variability [2, 3]. A variety of new architectures, including ultra-thin silicon-on-insulator (SOI), double gate, FinFETs, tri-gate, junctionless and gate all-around (GAA) nanowire transistors, have therefore been developed to improve the electrostatic control of the conducting channel. This is essential since a low Ioff implies low static power dissipation and it will therefore improve power management in the multi-billion transistors circuits employed globally in microprocessors, sensors and memories

Experimental and simulation study of 1D silicon nanowire transistors using heavily doped channels

The experimental results from 8 nm diameter silicon nanowire junctionless field effect transistors with gate lengths of 150 nm are presented that demonstrate on-currents up to 1.15 mA/m for 1.0 V and 2.52 mA/m for 1.8 V gate overdrive with an off-current set at 100 nA/m. On- to off-current ratios above 108 with a subthreshold slope of 66 mV/dec are demonstrated at 25 oC. Simulations using drift-diffusion which include densitygradient quantum corrections provide excellent agreement with the experimental results. The simulations demonstrate that the present silicon-dioxide gate dielectric only allows the gate to be scaled to 25 nm length before short-channel effects significantly reduce the performance. If high-K dielectrics replace some parts of the silicon dioxide then the technology can be scaled to at least 10 nm gatelength

Livestock producers' knowledge, attitude, and behavior (KAB) regarding antimicrobial use in Ethiopia

Introduction: Inappropriate antimicrobial use (AMU) in livestock production is an important aspect of the global burden of antimicrobial resistance (AMR). In Ethiopia, a low-income country with a large and increasing livestock population, AMU in food animals is not properly regulated. Hence, farmers are fully free to use antimicrobials to their (perceived) benefit. Therefore, understanding farmers' mindsets is important to improve antimicrobial stewardship in the livestock sector. Methods: This cross-sectional study was conducted to assess livestock disease management practices and knowledge, attitude, and behavior (KAB) among livestock producers regarding AMU, residues, and resistance, as well as factors potentially explaining differences in KAB. We determined the KAB of livestock owners of three selected districts of central and western Ethiopia (n = 457), using a pretested questionnaire administered through face-to-face interviews. Logistic regression was used to evaluate the association between potential explanatory variables and the KAB scores of the respondents. Results: The results showed that 44% of the farmers used antimicrobials in the past few years, where antibiotics (21%) and trypanocides (11%) were most widely used to manage livestock diseases. Furthermore, most farmers showed poor knowledge about AMU, residues, and AMR (94%) and unfavorable attitudes (<50% correct answers) toward contributing factors for AMR (97%). On the contrary, 80% of the respondents had overall good behavior scores (≥50% correct answers) related to AMU. Multivariate analysis results showed that having good knowledge, keeping ≥2 animal species, and the occurrence of ≥4 livestock diseases on the farm in a year were strong predictors of bad behavior scores (p < 0.05). The findings of the current investigation also revealed that the incidence of livestock diseases on the farm and a higher level of formal education significantly contributed to better knowledge and desirable attitudes but bad AMU behavior. Conclusion: A low level of awareness about and undesirable attitudes toward AMU and AMR could potentially affect farmers' behavior toward judicious AMU, thus requiring awareness creation efforts on livestock disease management practices

Assessment of animal African trypanosomiasis (AAT) vulnerability in cattle-owning communities of sub-Saharan Africa

Background: Animal African trypanosomiasis (AAT) is one of the biggest constraints to livestock production and a threat to food security in sub-Saharan Africa. In order to optimise the allocation of resources for AAT control, decision makers need to target geographic areas where control programmes are most likely to be successful and sustainable and select control methods that will maximise the benefits obtained from resources invested. Methods: The overall approach to classifying cattle-owning communities in terms of AAT vulnerability was based on the selection of key variables collected through field surveys in five sub-Saharan Africa countries followed by a formal Multiple Correspondence Analysis (MCA) to identify factors explaining the variations between areas. To categorise the communities in terms of AAT vulnerability profiles, Hierarchical Cluster Analysis (HCA) was performed. Results: Three clusters of community vulnerability profiles were identified based on farmers’ beliefs with respect to trypanosomiasis control within the five countries studied. Cluster 1 communities, mainly identified in Cameroon, reported constant AAT burden, had large trypanosensitive (average herd size = 57) communal grazing cattle herds. Livestock (cattle and small ruminants) were reportedly the primary source of income in the majority of these cattle-owning households (87.0 %). Cluster 2 communities identified mainly in Burkina Faso and Zambia, with some Ethiopian communities had moderate herd sizes (average = 16) and some trypanotolerant breeds (31.7 %) practicing communal grazing. In these communities there were some concerns regarding the development of trypanocide resistance. Crops were the primary income source while communities in this cluster incurred some financial losses due to diminished draft power. The third cluster contained mainly Ugandan and Ethiopian communities which were mixed farmers with smaller herd sizes (average = 8). The costs spent diagnosing and treating AAT were moderate here. Conclusions: Understanding how cattle-owners are affected by AAT and their efforts to manage the disease is critical to the design of suitable locally-adapted control programmes. It is expected that the results could inform priority setting and the development of tailored recommendations for AAT control strategies

The causes, treatment, and outcome of acute heart failure in 1006 Africans From 9 countries

Background: Acute heart failure (AHF) in sub-Saharan Africa has not been well characterized. Therefore,wesought to describe the characteristics, treatment, and outcomes of patients admitted with AHF in sub-Saharan Africa. Methods: The Sub-Saharan Africa Survey of Heart Failure (THESUS–HF) was a prospective, multicenter, observational survey of patients with AHF admitted to 12 university hospitals in 9 countries. Among patients presenting with AHF, we determined the causes, treatment, and outcomes during 6 months of follow-up. Results: From July 1, 2007, to June 30, 2010, we enrolled 1006 patients presenting with AHF. Mean (SD) age was 52.3 (18.3) years, 511 (50.8%) were women, and the predominant race was black African (984 of 999 [98.5%]). Mean (SD) left ventricular ejection fraction was 39.5% (16.5%)... Conclusions: In African patients, AHF has a predominantly nonischemic cause, most commonly hypertension. The condition occurs in middle-aged adults, equally in men and women, and is associated with high mortality. The outcome is similar to that observed in non- African AHF registries, suggesting that AHF has a dire prognosis globally, regardless of the cause

Gender differences in clinical characteristics and outcome of acute heart failure in sub-Saharan Africa: results of the THESUS-HF study

Background: The impact of gender on the clinical characteristics, risk factors, co-morbidities, etiology, treatment and outcome of acute heart failure in sub-Saharan Africa has not been described before. The aim of this study was to evaluate the sex diffe rences in acute heart failure in sub-Saharan Africa using the data from The sub-Saharan Africa Survey of Heart Failure (THESUS-HF). Methods and results: 1,006 subjects were recruited into this prospective multicenter, international observational heart failure survey. The mean age of total population was 52.4 years (54.0 years for men and 50.7 years for women). The men were significantly older (p = 0.0045). Men also presented in poorer NYHA functional class (III and IV), p = 0.0364). Cigarette smoking and high blood pressure were significantly commoner in men (17.3 vs. 2.6 % and 60.0 vs. 51.0 % respectively). On the other hand, atrial fibrillation and valvular heart disease were significantly more frequent in women. The mean hemoglobin concentration was lower in women compared to men (11.7 vs. 12.6 g/dl, p ≤ 0.0001), while the blood urea and creatinine levels were higher in men (p \u3c 0.0001). LV systolic dysfunctional was also seen more in men. Men also had higher E/A ratio indicating higher LV filling pressure. Outcomes were similar in both sexes. Conclusions: Although the outcome of patients admitted for AHF in sub-Saharan regions is similar in men and women, some gender differences are apparent suggesting that in men more emphasis should be put on modifiable life risk factors, while in women prevention of rheumatic heart diseases and improved nutrition should be addressed vigorously

Electroencephalographic Findings, Antiepileptic Drugs and Risk Factors of 433 Individuals Referred to a Tertiary Care Hospital in Ethiopia

Background: Little is known about the characteristics of electroencephalogram (EEG) findings in epileptic patients in Ethiopia. The objective of this&nbsp; study was to characterize the EEG patterns, indications, antiepileptic drugs (AEDs), and epilepsy risk factors.Methods: A retrospective observational review of EEG test records of 433 patients referred to our electrophysiology unit between July 01, 2020 and&nbsp; December 31, 2021.Results: The age distribution in the study participants was right skewed unipolar age distribution for both sexes and the mean age of 33.8 (SD=15.7) years. Male accounted for 51.7%. Generalized tonic clonic seizure was the most common seizure type. The commonest indication for EEG was&nbsp; abnormal body movement with loss of consciousness (35.2%). Abnormal EEG findings were observed in 55.2%; more than half of them were Interictal epileptiform discharges, followed by focal/or generalized slowing. Phenobarbitone was the commonest AEDs. A quarter (20.1%) of the&nbsp; patients were getting a combination of two AEDs and 5.2% were on 3 different AEDs. Individuals taking the older AEDs and those on 2 or more AEDs&nbsp; tended to have abnormal EEG findings. A cerebrovascular disorder (27.4%) is the prevalent risk factor identified followed by brain tumor, HIV&nbsp; infection, and traumatic head injury respectively.Conclusion: High burden of abnormal EEG findings among epileptic patients referred to our unit. The proportion of abnormal EEG patterns was&nbsp; higher in patients taking older generation AEDs and in those on 2 or more AEDs. Stroke, brain tumor, HIV infection and traumatic head injury were&nbsp; the commonest identified epilepsy risk factors

Regular Khat (Catha edulis) chewing is associated with elevated diastolic blood pressure among adults in Butajira, Ethiopia: A comparative study

<p>Abstract</p> <p>Background</p> <p>Fresh leaves and buds of the Khat plant (<it>Catha edulis</it>) contain Cathinone, an amphetamine like alkaloid responsible for its pharmacological action. Chewing of Khat has been associated with a transient rise in blood pressure and heart rate in experimental studies. Few studies examined the effect of regular or frequent Khat chewing on blood pressure at the population level. This study was conducted to examine the association of regular Khat chewing with blood pressure among adults.</p> <p>Methods</p> <p>We compared systolic and diastolic blood pressure of adults 35-65 years of age who reported regular chewing of Khat during the preceding five years to those who never chewed Khat during the same period. Study participants were recruited from purposively selected urban and rural villages of Butajira District in Ethiopia. The comparative groups, chewers (334) and non-chewers (330), were identified from among the general population through a house-to-house visit using a screening questionnaire. They were frequency-matched for sex and age within a five-year range. Data were collected through structured interviews and physical measurements including blood pressure, weight and height.</p> <p>Results</p> <p>The prevalence of hypertension was significantly higher among Khat chewers (13.4%) than non-chewers (10.7%), odds ratio (OR) = 1.66 (95% confidence interval (CI) 1.05, 3.13). A considerably high proportion of chewers (29.9%) than non-chewers (20.6%) had sub-optimal diastolic blood pressure (> 80 mmHg). The mean (sd) diastolic blood pressure was significantly higher among Khat chewers [75.0 (11.6)] than non-chewers [72.9 (11.7)], P < 0.05. Similarly, Khat chewers had significantly higher mean (sd) heart rate [76.3 (11.5)] than non-chewers [73.9 (12.6)], P < 0.05. There was no significant difference in mean systolic blood pressure between the two groups.</p> <p>Conclusion</p> <p>Regular chewing of Khat is associated with elevated mean diastolic blood pressure, which is consistent with the peripheral vasoconstrictor effect of Cathinone. Regular Khat chewing may have sustained effects on the cardiovascular system that can contribute to elevated blood pressure at the population level.</p

The effect of maternal common mental disorders on infant undernutrition in Butajira, Ethiopia: The P-MaMiE study

BACKGROUND: Although maternal common mental disorder (CMD) appears to be a risk factor for infant undernutrition in South Asian countries, the position in sub-Saharan Africa (SSA) is unclear METHODS: A population-based cohort of 1065 women, in the third trimester of pregnancy, was identified from the demographic surveillance site (DSS) in Butajira, to investigate the effect of maternal CMD on infant undernutrition in a predominantly rural Ethiopian population. Participants were interviewed at recruitment and at two months post-partum. Maternal CMD was measured using the locally validated Self-Reported Questionnaire (score of > or = six indicating high levels of CMD). Infant anthropometry was recorded at six and twelve months of age. RESULT: The prevalence of CMD was 12% during pregnancy and 5% at the two month postnatal time-point. In bivariate analysis antenatal CMD which had resolved after delivery predicted underweight at twelve months (OR = 1.71; 95% CI: 1.05, 2.50). There were no other statistically significant differences in the prevalence of underweight or stunted infants in mothers with high levels of CMD compared to those with low levels. The associations between CMD and infant nutritional status were not significant after adjusting for pre-specified potential confounders. CONCLUSION: Our negative finding adds to the inconsistent picture emerging from SSA. The association between CMD and infant undernutrition might be modified by study methodology as well as degree of shared parenting among family members, making it difficult to extrapolate across low- and middle-income countries