Underwater channel characterization to design wireless sensor network by Bellhop

Acoustic underwater link due to low attenuation is employed for underwater sensor network (UWSN). Due to water changing physical properties and different environmental conditions, the sound propagation for every underwater channel are different. So, the most important parameters to design reliable UWSN are: the shadow zone determination, optimum nodes placement, high signal to noise ratio and more power efficiency of nodes. This paper simulates underwater channel for 7 KHz carrier frequency, with measured physical water properties and remote sensing data. Based on defined scenario, the research determines optimum nodes placement and link budget analysis based on bottom to surface acoustic link. The paper utilizes Bellhop acoustic toolbox as a simulator, GeoMapApp program to collects bathymetry data and Aviso+ database to determine wind speed on sea surface. As a result the paper based on simulation of sound propagation in channel and transmission loss determination in depth and range, finds the optimum nodes positions and link budget calculation to prove the results

An Improved Slant Path Attenuation Prediction Method in Tropical Climates

An improved method for predicting slant path attenuation in tropical climates is presented in this paper. The proposed approach is based on rain intensity data R_0.01 (mm/h) from 37 tropical and equatorial stations; and is validated by using the measurement data from a few localities in tropical climates. The new method seems to accurately predict the slant path attenuation in tropical localities, and the comparative tests seem to show significant improvement in terms of the RMS of the relative error variable compared to the RMS obtained with the SAM, Crane, and ITU-R prediction models

Determination of Melting Layer Boundaries and Attenuation Evaluation in Equatorial Malaysia at Ku-Band

Upsurge in bandwidth demand in recent times for real-time data transmission have put serious constraints on satellite communication channels, leading to congestion of the lower frequency bands; necessitating migration to higher bands (Ku, Ka and V) with attendant problems such as signal fading, depolarization and attenuation due to presence of hydrometeors. There is need to separately account for attenuation due to the melting layer along the earth-space microwave links. One year data from ground-based S-band meteorological radar sourced from Kluang station of the Malaysian Meteorological Department was processed to build the vertical reflectivity of rain profile for UTM, Malaysia. Results from this work suggested that the effects of the melting layer on signal attenuation at Ku-band can be quite significant in the tropical and equatorial regions. It was estimated to be 13.36 dB and 15.44 dB at 0.01% of the time exceeded using Laws-parsons and Marshall-Palmer regression coefficients, respectively. Furthermore, it was observed that ITU-R. P.618-11 model largely under-estimated the attenuation along the slant-paths because of its failure to account for attenuation due to the melting layer in its formulation by its assumption of constant rain rate; thus rendering it unsuitable for rain attenuation predictions in the tropics

Chronic Kidney Disease in Police Forces Households in Khartoum, Sudan: Pilot Report

Introduction: In the Police Forces Hypertension, Diabetes, Renal Insufficiency and Thyroid Derangement (HyDRIT) pilot study we explored the prevalence, risk factors, awareness, treatment adequacy and complications of chronic kidney disease (CKD) and other non-communicable diseases among adult Police Forces households in two housing complexes in Khartoum, Sudan. Methods: Serum creatinine measurements and urine dipstick testing were performed for 273 individuals. The glomerular filtration rate (GFR) was estimated using the standardized Cockroft-Gault and the four variable MDRD formulas. CKD was defined as an estimated GFR of less than 60 ml/min/1.73m2 and/or proteinuria. Results: The overall prevalence of CKD was 11% (30/273) using the standardized Cockroft-Gault equation and 7.7% (21/273) using the four variable MDRD equation. According to the standardized Cockroft-Gault formula, 14 subjects had reduced GFR with negative urine dipstick testing, two subjects had both proteinuria and reduced GFR, and 14 subjects had proteinuria without reduction in GFR. None of those subjects was aware of his kidney problem. According to the standardized Cockroft-Gault formula, 14 of the identified CKD cases were hypertensive (46.7%); eight of them (57.1%) had a prior diagnosis of hypertension but none achieved therapeutic targets. Four of the identified CKD cases were diabetic (13.3%), three of whom had a prior diagnosis of diabetes mellitus with reasonably controlled blood sugar levels. Only age above 50 years and low educational level proved to be independent risk factors for CKD in multivariate analysis. Conclusion: The prevalence of CKD in the study population seems to be comparable to other countries. Keywords: awareness, chronic kidney disease, diabetes mellitus, hypertension, prevalence, Suda

Determination of the melting layer from meteorological radar data in Malaysia

A developed algorithm based on the vertical profile of radar reflectivity, has been applied to determine the boundaries of the melting layer and its thickness. The average values of the melting layer heights are compared with ITU-R recommendations and other obtained results in tropical regions at 500m resolution range. The results obtained showed lower values for heights of the melting layer

Health education and the control of urogenital schistosomiasis: assessing the impact of the Juma na Kichocho comic-strip medical booklet in Zanzibar

Endeavours to control urogenital schistosomiasis on Unguja Island (Zanzibar) have focused on school-aged children. To assess the impact of an associated health education campaign, the supervised use of the comic-strip medical booklet Juma na Kichocho by Class V pupils attending eighteen primary schools was investigated. A validated knowledge and attitudes questionnaire was completed at baseline and repeated one year later following the regular use of the booklet during the calendar year. A scoring system (ranging from 0.0 to 5.0) measured children's understandings of schistosomiasis and malaria, with the latter being a neutral comparator against specific changes for schistosomiasis. In 2006, the average score from 751 children (328 boys and 423 girls) was 2.39 for schistosomiasis and 3.03 for malaria. One year later, the score was 2.43 for schistosomiasis and 2.70 for malaria from 779 children (351 boys and 428 girls). As might be expected, knowledge and attitudes scores for schistosomiasis increased (+0.05), but not as much as originally hoped, while the score for malaria decreased (-0.33). According to a Kolmogorov-Smirnov test, neither change was statistically significant. Analysis also revealed that 75% of school children misunderstood the importance of reinfection after treatment with praziquantel. These results are disappointing. They demonstrate that it is mistaken to assume that knowledge conveyed in child-friendly booklets will necessarily be interpreted, and acted upon, in the way intended. If long-term sustained behavioural change is to be achieved, health education materials need to engage more closely with local understandings and responses to urogenital schistosomiasis. This, in turn, needs to be part of the development of a more holistic, biosocial approach to the control of schistosomiasis

Determination of Levels of Organochlorine, Organophosphorus, and Pyrethroid Pesticide Residues in Vegetables from Markets in Dar es Salaam by GC-MS

This study investigated the levels of pesticides and metabolites in vegetables from major markets in Dar es Salaam city, Tanzania. Samples of fresh cabbage, spinach, and onions from the markets were analysed for pesticide residues. Extraction was performed using acetone followed by dichloromethane : cyclohexane mixture and the extracts were cleaned up using Florisil. The compounds were determined by gas chromatography-mass spectrometry (GC-MS). Pesticides and metabolites were detected in 72.2% of the samples. The detected pesticide residues and their highest mean concentrations were p,p′-DDT 4.00 × 10−3 mg/kg, p,p′-DDD 6.40 × 10−1 mg/kg, o,p′-DDD 1.00 × 10−2 mg/kg, α-endosulfan 6.00 × 10−1 mg/kg, β-endosulfan 2.10 × 10−1 mg/kg, chlorpyrifos 3.00 mg/kg, and cypermethrin 4.00 × 10−2 mg/kg. The most frequently detected compounds were p,p′-DDD and chlorpyrifos. The order of contamination was spinach > cabbage > onions. Generally, there were no significant variations in concentrations of pesticide residues among samples and sampling sites, which indicated similarities in contamination patterns. The concentrations of contaminants were above the maximum residue limits (MRLs) in 33.3–50% of the samples. The findings indicated risks and concerns for public health

Rheumatoid arthritis onset after COVID-19 infection: a case report

At the end of 2019, coronavirus disease (COVID-19) outbreak is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). Worldwide researchers and physician try to explore the mechanisms of damage induced by virus, they focus on the short-term and long-term immune-mediated consequences induced by the virus infection. Every day discover a new pathological condition induced by virus and new symptoms and disease may occur after recovery from disease. Our case report is 41 years old, Indian lady who presented to our primary health care centre complaining of multiple small hand joints pain, both elbows and knees pain with swelling of them and prolonged morning stiffness, diagnosed seropositive rheumatoid arthritis (RA) (arthritis, positive rheumatoid factor (RF), and X-ray changes) after 1 month recovery from COVID-19 infection. She did not have any joint pain and she had negative RF before COVID-19 infection with no family history of RA

Chemical constituents and lipoxygenase inhibitory activity of Piper stylosum Miq.

ABSTRACT. Chemical constituents and lipoxygenase inhibitory activity of the aerial part of Piper stylosum have been studied. Fractionation and purification of the extracts afforded five lignans, identified as yangambin (1), sesamin (2), syringaresinol (3), pinoresinol (4), and medioresinol (5), together with other constituents; 4-allyl resorcinol, β-sitosterol, β-sitostenone, taraxerol, vanilin, and vanilic acid. The structures of these compounds were established by analysis of their spectral data, as compared to that of reported compounds. The lipoxygenase inhibitory activity of the extracts and isolated lignans were also evaluated.               KEY WORDS: Piperaceae, Piper, Piper stylosum, Lignan, Lipoxygenase Bull. Chem. Soc. Ethiop. 2019, 33(3), 587-592.   DOI: https://dx.doi.org/10.4314/bcse.v33i3.1