Performance assessment of lower VHF band for short‐range communication and geolocation applications

The focus of this paper is to characterize near‐ground wave propagation in the lower very high frequency (VHF) band and to assess advantages that this frequency band offers for reliable short‐range low‐data rate communications and geolocation applications in highly cluttered environments as compared to conventional systems in the microwave range. With the advent of palm‐sized miniaturized VHF antennas, interest in low‐power and low‐frequency communication links is increasing because (1) channel complexity is far less in this frequency band compared to higher frequencies and (2) significant signal penetration through/over obstacles is possible at this frequency. In this paper, we quantify the excess path loss and small‐scale fading at the lower VHF and the 2.4 GHz bands based on short‐range measurements in various environments. We consider indoor‐to‐indoor, outdoor‐to‐indoor, and non‐line‐of‐sight outdoor measurements and compare the results with measurements at higher frequencies which are used in conventional systems (i.e., 2.4 GHz). Propagation measurements at the lower VHF band are carried out by using an electrically small antenna to assess the possibility of achieving a miniaturized, mobile system for near‐ground communication. For each measurement scenario considered, path loss and small‐scale fading are characterized after calibrating the differences in the systems used for measurements at different frequencies, including variations in antenna performance.Key PointsLow VHF has favorable short‐range characteristics and low signal distortionPenetration through many layers of building walls is possible at low VHFNovel miniaturized VHF antennas with reasonable performance have been designedPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111943/1/rds20240.pd

Assessment of Handling Practices, Utilization and Concentration of Iodine in Iodized Salt at Wondo Genet town, Southern Ethiopia: A Crossectional Study

Iodine deficiency is severe public health problem in Ethiopia. One out of every 1000 population is mentally handicapped due to a congenital thyroid deficiency, and about 50,000 prenatal deaths are occurring annually due to iodine deficiency disorders.nbsp Even though the problem is serious, there were no adequate researches conducted. Therefore, this study focuses on assessment of handling practices of iodized salt and the amount of iodine concentration retained in iodized salts at households and retailers level in Wondo Genet town. The objective of this study was to assess handling practices and concentration of iodine across iodized salt consumption in retailers and households level. Two hundred ninety four households and seventh six retailers were selected by systematic random sampling method for survey using questionnaire and rapid test kit method was used to measure iodine concentration of salt used by the households. The result of this study indicated that iodized salt coverage was found to be 100 % at households and retailers level. Iodine level in the salt examined by iodometric titration, in this study was 4.4 to 70.9 ppm. This indicates the need for further improvement of handling practices of iodized salt. Iodine level in the salt examined by iodometric titration in this study was 60.54% of households and 65.79% retailers salt samples had 15 ndash 40 ppm iodine concentration. This shows that in the iodized salt there is no adequate iodine content in accordance with the nbsprecommendation. Majority of the households 37.4% add iodized salt half way during boiling of the food/coffee. Although the coverage of iodized salt in the study area was high but availability of adequate iodized salt at household level was low as compared to the WHO recommendation.There for this shows that handling practice of iodized salt at the household and retailer level and utilization practice at the household level is poor

Hypertension treatment practices and its determinants among ambulatory patients:Retrospective cohort study in Ethiopia

Objectives We examined determinants of achieving blood pressure control in patients with hypertension and of treatment intensification in patients with uncontrolled blood pressure (BP).Design A retrospective cohort study in six public hospitals, Ethiopia.Participants Adult ambulatory patients with hypertension and with at least one previously prescribed antihypertensive medication in the study hospital.Outcome Controlled BP (&lt;140/90 mm Hg) and treatment intensification of patients with uncontrolled BP.Results The study population comprised 897 patients. Their mean age was 57 (SD 14) years, 63% were females, and 35% had one or more cardiometabolic comorbidities mainly diabetes mellitus. BP was controlled in 37% of patients. Treatment was intensified for 23% patients with uncontrolled BP. In multivariable (logistic regression) analysis, determinants positively associated with controlled BP were treatment at general hospitals (OR 1.89, 95% CI 1.26 to 2.83) compared with specialised hospitals and longer treatment duration (OR 1.04, 95% CI 1.01 to 1.06). Negatively associated determinants were previously uncontrolled BP (OR 0.30, 95% CI 0.21 to 0.43), treatment regimens with diuretics (OR 0.68, 95% CI 0.50 to 0.94) and age (OR 0.99, 95% CI 0.98 to 1.00). The only significant-positive-determinant for treatment intensification was duration of therapy (OR 1.05, 95% CI 1.02 to 1.09).Conclusions The level of controlled BP and treatment intensification practice in this study was low. The findings suggest the need for in-depth understanding and interventions of the identified determinants such as uncontrolled BP on consecutive visits, older age and type of hospital.</p

Assessment of Handling Practices, Utilization and Concentration of Iodine in Iodized Salt at Wondo Genet town, Southern Ethiopia: A Crossectional Study

Iodine deficiency is severe public health problem in Ethiopia. One out of every 1000 population is mentally handicapped due to a congenital thyroid deficiency, and about 50,000 prenatal deaths are occurring annually due to iodine deficiency disorders.nbsp Even though the problem is serious, there were no adequate researches conducted. Therefore, this study focuses on assessment of handling practices of iodized salt and the amount of iodine concentration retained in iodized salts at households and retailers level in Wondo Genet town. The objective of this study was to assess handling practices and concentration of iodine across iodized salt consumption in retailers and households level. Two hundred ninety four households and seventh six retailers were selected by systematic random sampling method for survey using questionnaire and rapid test kit method was used to measure iodine concentration of salt used by the households. The result of this study indicated that iodized salt coverage was found to be 100 % at households and retailers level. Iodine level in the salt examined by iodometric titration, in this study was 4.4 to 70.9 ppm. This indicates the need for further improvement of handling practices of iodized salt. Iodine level in the salt examined by iodometric titration in this study was 60.54% of households and 65.79% retailers salt samples had 15 ndash 40 ppm iodine concentration. This shows that in the iodized salt there is no adequate iodine content in accordance with the nbsprecommendation. Majority of the households 37.4% add iodized salt half way during boiling of the food/coffee. Although the coverage of iodized salt in the study area was high but availability of adequate iodized salt at household level was low as compared to the WHO recommendation.There for this shows that handling practice of iodized salt at the household and retailer level and utilization practice at the household level is poor

Relay Selection Based Full-Duplex Cooperative Systems under Adaptive Transmission

The present work analyzes multi-relay full-duplex systems with relay selection under multipath fading conditions in the context of channel capacity under: i) optimum power and rate adaptation; ii) truncated channel inversion with fixed rate. Useful analytic expressions are derived for these measures as well as for the associated optimum cut-off level. The offered results are then employed in the analysis of the corresponding end-to-end performance by also quantifying the effects of the involved relay self-interference. It is shown that high capacity levels are achieved even for a moderate number of relays and self-interference levels, at no considerably added system complexity. This is particularly useful in demanding emerging applications that are subject to transmit power constraints or fixed rate requirements

Elevated atmospheric CO2 suppresses silicon accumulation and exacerbates endophyte reductions in plant phosphorus

Many temperate grasses are both hyper-accumulators of silicon (Si) and hosts of Epichloë fungal endophytes, functional traits which may alleviate environmental stresses such as herbivore attack. Si accumulation and endophyte infection may operate synergistically, but this has not been tested in a field setting, nor in the context of changing environmental conditions. Predicted increases in atmospheric CO2 concentrations can affect both Si accumulation and endophyte function, but these have not been studied in combination. We investigated how elevated atmospheric CO2 (eCO2), Si supplementation, endophyte-presence and insect herbivory impacted plant growth, stoichiometry (C, N, P and Si), leaf gas exchange (rates of photosynthesis, stomatal conductance, transpiration rates) and endophyte production of anti-herbivore defences (alkaloids) of an important pasture grass (tall fescue; Lolium arundinaceum) in the field. eCO2 and Si supplementation increased shoot biomass (+52% and +31%, respectively), whereas herbivory reduced shoot biomass by at least 35% and induced Si accumulation by 24%. Shoot Si concentrations, in contrast, decreased by 17%–21% under eCO2. Si supplementation and herbivory reduced shoot C concentrations. eCO2 reduced shoot N concentrations which led to increased shoot C:N ratios. Overall, shoot P concentrations were 26% lower in endophytic plants compared to non-endophytic plants, potentially due to decreased mass flow (i.e. observed reductions in stomatal conductance and transpiration). Alkaloid production was not discernibly affected by any experimental treatment. The negative impacts of endophytes on P uptake were particularly strong under eCO2. We show that eCO2 and insect herbivory reduce and promote Si accumulation, respectively, incorporating some field conditions for the first time. This indicates that these drivers operate in a more realistic ecological context than previously demonstrated. Reduced uptake of P in endophytic plants may adversely affect plant productivity in the future, particularly if increased demand for P due to improved plant growth under eCO2 cannot be met. Read the free Plain Language Summary for this article on the Journal blog. © 2023 The Authors. Functional Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society

Switching head group selectivity in mammalian sphingolipid biosynthesis by active-site-engineering of sphingomyelin synthases

SM is a fundamental component of mammalian cell membranes that contributes to mechanical stability, signaling, and sorting. Its production involves the transfer of phosphocholine from phosphatidylcholine onto ceramide, a reaction catalyzed by SM synthase (SMS)1 in the Golgi and SMS2 at the plasma membrane. Mammalian cells also synthesize trace amounts of the SM analog, ceramide phosphoethanolamine (CPE), but the physiological relevance of CPE production is unclear. Previous work revealed that SMS2 is a bifunctional enzyme producing both SM and CPE, whereas a closely related enzyme, SMS-related protein (SMSr)/SAMD8, acts as a monofunctional CPE synthase in the endoplasmic reticulum. Using domain swapping and site-directed mutagenesis on enzymes expressed in defined lipid environments, we here identified structural determinants that mediate the head group selectivity of SMS family members. Notably, a single residue adjacent to the catalytic histidine in the third exoplasmic loop profoundly influenced enzyme specificity, with Glu permitting SMS-catalyzed CPE production and Asp confining the enzyme to produce SM. An exchange of exoplasmic residues with SMSr proved sufficient to convert SMS1 into a bulk CPE synthase. This allowed us to establish mammalian cells that produce CPE rather than SM as the principal phosphosphingolipid and provide a model of the molecular interactions that impart catalytic specificity among SMS enzymes

Sphingomyelin synthase-related protein SMSr controls ceramide homeostasis in the ER

Ceramides are central intermediates of sphingolipid metabolism with critical functions in cell organization and survival. They are synthesized on the cytosolic surface of the endoplasmic reticulum (ER) and transported by ceramide transfer protein to the Golgi for conversion to sphingomyelin (SM) by SM synthase SMS1. In this study, we report the identification of an SMS1-related (SMSr) enzyme, which catalyses the synthesis of the SM analogue ceramide phosphoethanolamine (CPE) in the ER lumen. Strikingly, SMSr produces only trace amounts of CPE, i.e., 300-fold less than SMS1-derived SM. Nevertheless, blocking its catalytic activity causes a substantial rise in ER ceramide levels and a structural collapse of the early secretory pathway. We find that the latter phenotype is not caused by depletion of CPE but rather a consequence of ceramide accumulation in the ER. Our results establish SMSr as a key regulator of ceramide homeostasis that seems to operate as a sensor rather than a converter of ceramides in the ER