Modeling Ground Penetrating Radar (GPR) Technology for Seed Planting Depth Detection using Numerical Scheme based on Finite Difference Time Domain (FDTD) Method

Ground Penetrating Radar (GPR) is an electromagnetic (EM) signal based technology, commonly used as a non-destructive technique to explore subsurface features and identify different depth profiles in materials. The overall goals of this work is to evaluate GPR for non-destructive mapping of seed planting depth. Soils are inherently complex materials and numerous factors affect GPR behavior. The fundamental factors affecting GPR response are dielectric permittivity, magnetic permeability, and electrical conductivity, which are influenced by soil bulk density, texture, salinity, organic matter, volumetric water content, seed properties and physical geometry. To successfully optimize GPR’s ability to detect seed planting depth, the influence of these factors must be evaluated. This paper describes the development of a single dimensional GPR simulation model, based on finite difference time domain (FDTD) method, to evaluate the use of GPR sensing of seed planting depth. The simulation results shows that the EM signal is highly sensitive to high values of the electrical conductivity. High permittivity values decrease the EM signal velocity, wavelength and strength. A combination of these two properties leads to a significant EM signal attenuation ranging from 0 to ~ 800 dBm-1 as the signal traverses through the soil and seed. The lack of sufficient dielectric contrast between soil and seed presents a challenge on the detectability of the reflected signal by the radar receiver, therefore a sufficient dielectric contrast between the soil and seed has to be present to allow the GPR to be a viable tool to map the seed planting depth

Physical and Chemical Characteristics of Five Hot Springs in Eritrea

Eritrea has a number of hot springs whose physicochemical characteristics are not documented. This study examined the thermal and chemical features of five hot springs located in the eastern escarpment of Eritrea. Field data and water samples were collected from five hot springs namely; Akwar and Maiwooi near Gahtelai, Garbanabra and Gelti near Irafayle at the Gulf of Zula and Elegedi in Alid volcanic center. The water temperatures at source varied from 49.5°C to 100°C while pH levels ranged from 6.97 to 7.54. Elegedi had significantly higher temperature (p < 0.05) than the other four hot springs. Strong correlation was observed between electrical conductivity (EC), total dissolved solid (TDS), salinity, sodium, potassium, calcium and chloride (R2 > 0.9) as well as between temperature and sulphate levels (R2 = 0.96). Evident clustering was noted at p < 0.05, using Non-metric multidimensional scaling (NMDS), between the three locations of the hot springs. Akwar and Maiwooi, situated close to each other, clustered together, Garbanabra and Gelti, which were characterized by higher salinity levels, formed a separate cluster. Elegedi, characterized by high temperature (100°C), sulphate (979.7 mg/l) and NH4+ (196.33 mg/l) levels, clustered separately. Akwar and Maiwooi had high bicarbonate (345 mg/l and 393 mg/l) and fluoride (8.20 mg/l and 6.48 mg/l) levels which are above WHO limits. Electrical conductivity (23,133 mS/cm), total dissolved solid (15,552 mg/l), sodium (3,800 mg/l), potassium (198 mg/l), calcium (1,653 mg/l) and chloride (5,946 mg/l) levels in Garbanabra and Gelti hot springs exceeded WHO limits. Bromine (74.8 mg/l in Garbanabra and 45.2 mg/l in Gelti) and boron (2.21 mg/l in Garbanabra and 1.55 mg/l in Gelti) levels were also above standard limits set for potable water. Maiwooi (1.20) and Elegedi (1.10) were depositional while Akwar water (-0.71) was slightly corrosive. The corrosive nature of the water sample from Akwar, is a public health concern. The waters from the five Eritrean hot springs are thus not fit for human consumption. In addition, the use of thermal spring water for recreational purposes should be closely monitored. Keywords: key words, hot springs, physicochemical, Eritre

Optimization-oriented RAW modeling of IEEE 802.11ah heterogeneous networks

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The new medium access method of IEEE 802.11ah, called Restricted Access Window (RAW), divides stations into different groups, and only allows stations in the same group to access the channel simultaneously, in order to reduce collisions and thus achieve better performance (e.g., throughput). However, the existing station grouping strategies only support homogeneous scenarios where all stations use the same modulation and coding scheme (MCS) and packet size. A surrogate model is an efficient mathematical model that represents the behavior of a complex system, trained with a limited set of labeled input-output data samples. In this paper, we present a surrogate model that can accurately predict RAW performance under a given Restricted Access Window (RAW) configuration in heterogeneous networks. Different from the homogeneous scenario, heterogeneous networks are defined by a large number of parameters, leading to an enormous design space, i.e., the order of 1017 possible data points. This is too big to achieve feasible training convergence. In this paper, we present a novel training methodology that leads to a new design space with highly reduced size, i.e., the order of 105 data points. The surrogate model converges when less than 6000 labeled data points are used for training, which is only a tiny portion of the whole design space. The results show that, the relative error between model prediction and simulation results is less than 0.1 for 95% of the data points, in the areas of the design space studied. Its low complexity and high precision make the proposed model a valuable tool to develop real-time RAW optimization algorithms for heterogeneous IEEE 802.11ah networks.Postprint (author's final draft

Comparison of stroke knowledge before and after education in Ethiopia (The ask project)

Background: In order to address the growing burden of stroke in Africa, it is essential to have teaching tools that are accessible to a wide variety of communities. Resources for stroke, recognition of symptoms, steps to assist a stroke victim, or any educational tools are scarce. In order to increase education about stroke, we introduced a stroke education intervention in Bahir Dar, Ethiopia in the Amharic language. The aim of the intervention was to see if stroke knowledge and recognition of stroke symptoms increased post-education. Methods: An anonymous pre-test questionnaire was given to identify their baseline stroke knowledge, and then participants viewed the video about stroke. The Amharic BE-FAST acronym was introduced in the video to evaluate participants’ retention of stroke symptoms, while emphasizing the importance of rapid response. Participants were given a survey to post-test survey of their short-term memory recall, along with another satisfaction survey. Results: Over 50% of participants remembered all five letters of the Amharic BE-FAST acronym, nearly 80% answered that they learned about stroke prevention, 90% were satisfied with the video, and 98% thought it should be available widely to the general public. The data presented showed that there was an improvement in stroke education retention with the use of the stroke education video. Conclusions: The Amharic BE-FAST acronym demonstrated to be an effective tool in communicating the symptoms of stroke from English to Amharic. Stroke education was well received, which provided insight on how to design and implement new medical concepts in native languages.   French title:Connaissances sur les accidents vasulaires cerebraux avant et apres une education en Éthiopie (Projet ask)   Introduction: Afin de faire face au fardeau croissant des AVC en Afrique, il est essentiel de disposer d'outils pédagogiques accssibles à une grande variété de communautés. Les ressources pour l'AVC, la reconnaissance des symptômes, les étapes pour aider une victime d'AVC ou tout autre outil éducatif sont rares. Afin d'accroître l'éducation sur l'AVC, nous avons introduit une intervention d'éducation sur l'AVC à Bahir Dar, en Ethiopie, en langue amharique. Le but de l'intervention était de voir si la connaissance et la reconnaissance des symptômes de l'AVC augmentaient après l'éducation. Méthodes: Un questionnaire pré-test anonyme a été donné pour identifier leurs connaissances de base sur l'AVC, puis les participants ont visionné la vidéo sur l'AVC. L'acronyme amharique BE-FAST a été introduit dans la vidéo pour évaluer la rétention des symptômes d'AVC par les participants, tout en soulignant l'importance d'une réponse rapide. Les participants ont reçu une enquête pour post-test de leur mémoire à court terme, ainsi qu'une autre enquête de satisfaction. Résultats: Plus de 50% des participants se sont souvenus des cinq lettres de l'acronyme amharique BE-FAST, près de 80% ont répondu avoir appris la prévention des AVC, 90% étaient satisfaits de la vidéo et 98% pensaient qu'elle devrait être largement accessible au grand public. Les données présentées ont montré qu'il y avait une amélioration de la rétention de l'éducation sur l'AVC grâce à l'utilisation de la vidéo d'éducation sur l'AVC. Conclusion: L'acronyme amharique BE-FAST s'est révélé être un outil efficace pour communiquer les symptômes de l'AVC de l'anglais à l'amharique. L'éducation sur l'AVC a été bien accueillie, ce qui a permis de comprendre comment concevoir et mettre en oeuvre de nouveaux concepts médicaux dans les langues maternelles

Phenolic composition and antioxidant activities of cladodes of the two varieties of cactus pear (Opuntia ficus-indica) grown in Ethiopia

In this study, young cladodes corresponding to two (thorn-less and thorn-containing) varieties of cactus pear (Opuntia ficus-indica) from four different areas of Tigray region, Ethiopia, were investigated for their phenolic contents and antioxidant activities. Quantitative estimation of total phenolic contents and antioxidant activities in the cladodes was carried out using spectrophotometric methods. A 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay was used for the determination of the antioxidant activities, while Folin-Ciocalteau reagent, aluminum chloride and protein (albumin) precipitation methods were used for the determination of total polyphenol, flavonoid and tannin contents, respectively. The cladodes were found to be rich in polyphenols, with values in the range 18.0-71.4 mg gallic acid equivalent (GAE)/g of dry weight (DW). The predominant part of the polyphenols is represented by tannins, 9.00-41.2 mg GAE/g of DW, followed by flavonoids, 6.40-25.0 mg catchin equivalent (CE)/g of DW. The cladodes showed strong antioxidant activities, 59.3-85.8% inhibition compared to ascorbic acid. Application of paired t-test on the overall mean total polyphenol contents of samples collected from the different areas revealed the presence of significant variation between the thorn-less (31.6 GAE/g of DW) and thorn-containing (47.7 GAE/g of DW) varieties. One-way ANOVA also revealed that there are significant variations among samples from the same variety but collected from different areas

Multi-Class ECG Feature Importance Rankings: Cardiologists vs. Algorithms

Cardiologists have been using electrocardiogram features to diagnose a wide variety of heart conditions for many decades. There are also numerous algorithms that rank feature importance for a particular classification task. However, different algorithms often give quite different feature rankings. Therefore, we compared the feature importance rankings obtained by various algorithms with the features that cardiologists use for diagnosis

Prevalence and significance of sexually transmitted diseases among Ethiopian women attending antenatal clinics in Addis Ababa

Abstract: To determine the prevalence of sexually transmitted diseases (STDs) and the risk for (i) the mother regarding pregnancy wastage and puerperal sepsis and (ii) the child with regard to congenital and neonatal infection, 342 routine antenatal clinic (ANC) at tenders were investigated. The prevalence of antibodies showing exposure to specific STD pathogens in pregnant women attending ANC was: syphilis (TPHA) 27%, (VDR:) 28%, gonorrhoea 43%, genital chlamydiae 54%, HBV 37%, HSV-2 35 %, H ducreyi 10%. High titre seropositivity suggestive of active infection was: gonorrhoea 10%, genital chlamydiae 31 %, HSV2 19%; with HBV SAg 5% -all of which are likely to be transmitted to the foetus in utero or during delivery. Only 10% of ANC at tenders had no serological evidence of any STD: 72% had serological evidence for two or more STDs. Among conditions requiring treatment vaginitis was the most important, 20% having a severe trichomonal infection. Despite the frequency of this condition it was noted that few women (4%) complained of vaginal discharge. Thus women attending the ANC revealed a high prevalence of STD. Consequently the foetus and neonate are put at risk because of intrauterine or intrapartum transmission of infection. The high prevalence among ANC at tenders also reflects the relative prevalence of STDs in the community. Measures such as screening at ANC and information and education regarding prevention are required to reduce STDs in pregnant women and their sexual partners. Prophylaxis for the neonate can be considered until this goal is achieved. [Ethiop. J. Health Dev. 1995;9(1):31-40

A sociological and serological study of at tenders of family planning clinics in Addis Ababa

Abstract: A study of 542 women attending family planning clinics (FPC) and 1568 women attending obstetric and gynaecologic clinics in Addis Ababa showed utilisation of FPC was highest in those with a family income of 100-500 EB per month (36%), in women who were: Tigrawi (33%) or Amara (31 %), aged 20-34 years (30%), age 16 or older at first marriage/coitus (28%), parity of 2... 2 children (35%), > 5 lifetime husbands/sexual partners (39%), or were bargirls (73%) or prostitutes (43%). FPC attendance was lowest among the nulliparous (2.3%), women from rural areas (10%), the Guragie (10%) and Oromo women (19%), Moslem women 14(%), those of subsistence income ( < 10EB per month) (14%). The seroprevalence rates indicative of exposure to STD pathogens were high as was the prevalence of essentially asymptomatic pelvic inflammatory disease (PID). Only 4% of FPC at tenders had no serological evidence of STD: 64% had 3 or more different STD. Specific present or active STD infection prevalence for syphilis (VDRL) 28%, Neisseria gonorrhoea 31 %, genital chlamydia 46% and HSV-2 21% was higher in FPC at tenders than among women attending other clinics. Clinical evidence of PID was also more common in the FPC at tenders (54%), 37% having evidence of salpingitis. Thus FPCs provide a useful setting for screening women particularly at risk. Because of lack of symptoms, these women are unlikely to attend either an STDs clinic or a hospital for routine check up, and as such are not treated and represent a population from which STDs can spread into the population. Measures to screen, treat and educate FPC at tenders, their partners and their clients, are recommended in an attempt to Control STDs and ultimately HIV in the community. [Ethiop. J. Hea/th Dev. 1995;9(1):19-30