43 research outputs found
Development and evaluation of a free-field voice test for potential use as a community screening tool for hearing impairment in children
No full textEarly identification of hearing impairment in children is essential to avoid potentially disabling effects of hearing loss or deafness. This necessitates effective screening measures appropriate to the community in question. Current methods used in South Africa, especially for pre-school and school going children have resulted in poor coverage as they are designed for the more developed countries. There is thus a need to devise a screening method that is appropriate to our local conditions. In this study, a free-field live voice test was developed based on three levels: whisper, conversational and loud. This was evaluated against pure tone audiometry for sensitivity, specificity, cost and ease of application in two studies: hospital and school- based. A total of 394 children were tested; 189 in hospital-based study and 205 in school based study. 378 of the total were eligible for analysis. In the hospital-based study, the results of 177 children were analysed. The age range was 3 - 12 years with a mean of 5.8 years. The sensitivity (ability of the test to detect hearing impairment) was 80.0%; and the specificity (ability to identify children with normal hearing) was 95.0%. In the school-based study, done after modification and standardisation of the test set, the sensitivity and specificity were 83.3% and 97.8% respectively. Age range was 3 - 8 years with 79% being 4- 6 years. In both studies, the voice test was simpler to perform, easily understood and acceptable to the children and the testers; and considerably cheaper as the only equipment required was picture/toy set. The main limitation was non-standardisation of the test set. This was rectified in the school-based study. The drawbacks noted were the inability of the voice test to detect unilateral hearing loss/deafness and high frequency hearing loss. The voice test generally correlated well with pure tone audiometry and could be used as alternative for screening for hearing impairment in the community especially for pre-school and school going children. However, it is recommended to repeat the study in actual community settings using Community Health Care Workers as the testers. This would also determine the reliability of the voice test, as this cannot be reliably established at this stage
Effect of behavioural factors on the investment risk profile of investment schemes members in Nairobi County
No full textFull- text thesisStudies conducted in behavioral finance science provide diverging and inconclusive results with respect to how behavioral biases blur investment decision making. Additionally, behavioral science studies have provided differing results compared to arguments of traditional finance theories, which suggest that investors are rational and make investment decisions after keen analysis of all available information. Behavioral finance suggests that investment decisions are greatly affected by irrational, emotional and psychological factors. It is against this background that the current study was premised to examine the effect of psychological biases and heuristics on the investment risk profile of members of investment schemes in Kenya. The study sought to respond to the following objectives: to assess the effect of heuristics on the investment risk profile of investment group (chama) members in Nairobi County and to examine the effect of psychological biases on the investment risk profile of investment group (chama) members in Nairobi County. The study was guided by behavioral finance theory and employed an explanatory research design. The study targeted all the 121 registered Chamas in Nairobi (Kenya Association of Investment Groups (KAIG) database). The study targeted three employees drawn from each of the chamas. The data analysis phase applied both descriptive and ordinal regression analysis. The survey was able to obtain an 81% response rate with only 19% of the considered sample respondents not able to present their questionnaires within the provided timeframe. Findings pointed out that most of the groups 48% had 11-30 members, 29% had 31-60 members with 18% having less than 10 members. The correlation results revealed that there was a weak positive and significant association between psychological biases, demographic factors and the investment risk profile of investment groups in Nairobi County. The correlation tests also revealed a strong positive and significant association between heuristic biases and the investment risk profile of investment groups in Nairobi County. Based on the study’s first objective, the study concluded that psychological biases and heuristic biases have a positive and significant effect on investment risk profile of investment groups in Nairobi County. Finally, the study concluded that demographic factors had an insignificant control effect on the investment risk profile of investment groups. The study recommended for oversight and supervision of investment groups to ensure that they comply with relevant laws and regulations. This can help to protect investors and promote a fair and transparent investment environment. Further individual groups should also establish a rigorous investment appraisal process that incorporates multiple perspectives and considers all relevant factors. The study also recommends that Chamas adopt a diversified investment strategy across different asset classes and industries to mitigate the risk of loss associated with concentration risk. This can help to minimize the impact of any single investment's performance on their overall portfolio
Effect of maternal Schistosoma mansoni infection and praziquantel treatment during pregnancy on Schistosoma mansoni infection and immune responsiveness among offspring at age five years.
No full textINTRODUCTION: Offspring of Schistosoma mansoni-infected women in schistosomiasis-endemic areas may be sensitised in-utero. This may influence their immune responsiveness to schistosome infection and schistosomiasis-associated morbidity. Effects of praziquantel treatment of S. mansoni during pregnancy on risk of S. mansoni infection among offspring, and on their immune responsiveness when they become exposed to S. mansoni, are unknown. Here we examined effects of praziquantel treatment of S. mansoni during pregnancy on prevalence of S. mansoni and immune responsiveness among offspring at age five years. METHODS: In a trial in Uganda (ISRCTN32849447, http://www.controlled-trials.com/ISRCTN32849447/elliott), offspring of women treated with praziquantel or placebo during pregnancy were examined for S. mansoni infection and for cytokine and antibody responses to SWA and SEA, as well as for T cell expression of FoxP3, at age five years. RESULTS: Of the 1343 children examined, 32 (2.4%) had S. mansoni infection at age five years based on a single stool sample. Infection prevalence did not differ between children of treated or untreated mothers. Cytokine (IFNγ, IL-5, IL-10 and IL-13) and antibody (IgG1, Ig4 and IgE) responses to SWA and SEA, and FoxP3 expression, were higher among infected than uninfected children. Praziquantel treatment of S. mansoni during pregnancy had no effect on immune responses, with the exception of IL-10 responses to SWA, which was higher in offspring of women that received praziquantel during pregnancy than those who did not. CONCLUSION: We found no evidence that maternal S. mansoni infection and its treatment during pregnancy influence prevalence and intensity of S. mansoni infection or effector immune response to S. mansoni infection among offspring at age five years, but the observed effects on IL-10 responses to SWA suggest that maternal S. mansoni and its treatment during pregnancy may affect immunoregulatory responsiveness in childhood schistosomiasis. This might have implications for pathogenesis of the disease
Field Investigation into Abrasion of Concrete at a Coastal Stepped Revetment: A U.K. Case Study
No full textAlthough concrete abrasion damage is a major maintenance challenge for coastal structures fronted by beaches with hard coarse sediments, there are no readily available field studies that have measured abrasion damage of known concrete mixtures under defined exposure conditions. The objective of this investigation is to evaluate the abrasive exposure conditions of the concrete revetment armour units at Cleveleys on the Fylde coast of the U.K. and examine the feasibility of using terrestrial laser scanning (TLS) to measure concrete abrasion damage in field conditions. It was found that the concrete elements at Cleveleys are exposed to a macro-tidal environment, which experiences significant wave heights that vary from 0.42 to 1.92 m, whilst the peak wave periods range from 3.7 to 6.5 s. The beach sediments have a mean size of 26 mm and are moderately sorted. TLS provides a dense point cloud of abraded surfaces suitable for quantitative assessment of concrete abrasion in the field. Based on the measured abrasion depths and exposure durations, the peak concrete abrasion rates at the site varied from 3.5 to 4.5 mm/year, and severe abrasion was concentrated in the region between mean high-water springs and mean high-water neaps, wherein the highest beach levels were also found during the survey. Finally, the abraded surfaces exhibited a polished texture with no visible craters; thus, the mechanism of concrete material loss was by grinding/polishing due to rolling/sliding sediments
Participation of Local Communities in the Management of Wetlands in Magadi Area, Kenya
No full textWetlands are lands that are transitional between terrestrial and aquatic systems where the water is usually at or near the surface of the land or land that is covered with shallow water (Cowardin et al. 1979, Roggeri 1995). In the context of dry lands, wetlands are areas that are permanently, seasonally or occasionally water logged with fresh or saline water that supports characteristic animals and plants. In the dry lands of eastern Africa, wetlands cover about 3 percent of the total land area and include shallow lakes and margin s of deep lakes, swamps and marshes found on upper flood plains of major rivers, coastal river flood plains and high mountain peat bogs and tarns (Omoding 1995). These ecosystems support valuable biodiversity, including large numbers of mammals, reptiles, fishes and birds as well as diverse plant communities (Denny 1993). They also provide valuable resources and environmental benefits, such as biomass cropping for livestock pasture, water supply, agriculture, fisheries and subsistence hunting of wildlife that sustain local economies and communities (Shumway 1999)
Acceptability of pre-exposure prophylaxis and associated factors among HIV-negative young men in Kagwara fishing community-Serere district, Uganda: A cross-sectional study
No full textAbbreviations: AGYW, adolescent girls
and young women; AIDS, Acquired
Immunodeficiency Syndrome; AVERT, Aid
Virus Education and Research Trust; AYFRHS,
Adolescent and Youth Friendly Reproductive
Health Care Services; CDC, Centers for Disease
Control and Prevention; DHIS2, District Health
Information System Software version 2; HIV,
Human Immunodeficiency Virus; HMIS, Health
Management Information System; MSM, Men
who have sex with Men; MSMW, Men who have
Sex with Men and Women; NRTIs, Nucleotide
Reverse Transcriptase Inhibitors; PrEP, pre-
exposure prophylaxis; PWID, People Who Inject
Drugs; PWUD, People Who Use Drugs; STD,
Sexually Transmitted Disease (s); UN, United
Nations; UNAIDS, United Nations Joint Program
on HIV; UNFPA, United Nations Fund for
Population Activities; UNICEF, United Nations
International Children’s Emergency Fund; WHO,
World Health OrganizationBackground
Despite the potential efficacy of Pre-Exposure Prophylaxis (PrEP) in reducing HIV
risk, Oral PrEP acceptability remains strikingly varied by populations and locations.
We assessed PrEP acceptability and associated factors among at-risk HIV-negative
young men.
Methods
A cross-sectional analytical study design was used. Data were collected among
409 at-risk HIV-negative young men aged 15–24 years living in Kagwara fishing
community- Serere district, Uganda between August and October 2023. Quantitative
data were collected on socio-demographic characteristics, sexual risk behaviors
and concerns about PrEP. Data was analyzed using Stata version 15.0 statistical
software. Summary statistics were computed and presented as tables, frequencies
and proportions. Bivariate analysis was conducted using binary logistic regression to
identify independent factors associated with PrEP acceptability. All factors that had
p < 0.10 at the bivariate analysis and confounders were entered into the final logistic
regression model. All factors with p < 0.05 were considered significantly associated
with the primary outcome
Results
The average age of 409 respondents was 21.8 (Standard Deviation [SD]=1.9) years.
Majority, (97.8%, n = 393) had unprotected penetrative sex. PrEP acceptability was high as majority of the participants accepted to use PrEP based on the six constructs
of acceptability (93.6%, n = 383). Participants with perceived risk of getting HIV
infection had higher odds of PrEP acceptability, (adjusted odds ratio [aOR]=4.23,
95%CI = 1.05–17.04). Participants who knew their partner’s HIV status (aOR=0.25,
95%CI = 0.07–0.88), those who felt embarrassed to ask for PrEP from the facility
(aOR=0.12, 95%CI = 0.04–0.39), and those who had stigma associated with use of
PrEP (aOR=0.13, 95%CI = 0.04–0.41) had reduced odds of PrEP acceptability.
Conclusion
We found a high level of PrEP acceptability among young men at risk of HIV acqui
sition in Kagwara fishing community. Improving access to PrEP services among
high risk young men in the fishing communities may increase PrEP uptake in this
population and across similar settings. The Ministry of health needs to use multiple
approaches to provide PrEP such as peer-led models, drug distribution points, short
message reminders for refills, pharmacies and retail drug shops.he author(s) received no specific funding for this work
New heteroleptic tertiary phosphane-based Ni(ii) 3,4-dimethoxyphenylacetonitriledithiolates:bifunctional electrocatalysts for homogeneous HER and heterogeneous OER
No full textConstruction of highly efficient non-platinum complexes as catalysts for electrochemical water splitting is the need of time. Herein, three new Ni(II)-based dithiolates, with formulas of [(dpdt)Ni(dppe)] (Ni-dpe), [(dpdt)Ni(dppf)] (Ni-dpf) and [(dpdt)Ni(PPh3)2] (Ni-pph) (dpdt = 3,4-dimethoxyphenylacetonitriledithiolate, dppe = 1,2-bis(diphenylphosphino)ethane, dppf = 1,1′-bis(diphenylphosphino)ferrocene and PPh3 = triphenylphosphane), were synthesized and characterized. Single-crystal X-ray diffraction analysis of Ni-dpe revealed a distorted square planar coordination environment around nickel(II) fulfilled by two S and two P of the dpdt2− and dppe ligands, respectively. Various non-covalent interactions, such as C–H⋯C, C–H⋯S and C–H⋯O, stabilized the lattice of Ni-dpe, and their nature was investigated using Hirshfeld surface analysis. Furthermore, the activities of these complexes as homogeneous electrocatalysts for HERs using trifluoroacetic acid (TFA) as a proton source and heterogeneous electrocatalysts for OERs in an aqueous KOH solution were evaluated. For homogeneous electrocatalysis, turnover frequencies (TOFs) of 402, 655 and 1761 s−1 for Ni-dpe, Ni-dpf and Ni-pph were observed, respectively, at 100 mM TFA. The better electrocatalytic activity of Ni-pph was ascribed to the spatial flexibility of the PPh3 ligands, which facilitated attainment of a more stable transition state than those of other complexes. For heterogeneous OERs, the results suggested that Ni-dpf displayed the lowest Tafel slope of 64 mV dec−1 and the highest current density of 53.47 mA cm−2, thereby exhibiting the best electrocatalytic activity
Positional isomeric triphenylphosphine appended tetrahedral Cu(I) 2-/3-/4-methylpyridyldithiocarbonates as heterogeneous molecular electrocatalysts for OER and HER
No full textThree Cu(I) complexes with positional isomeric methylpyridyldithiocarbonates as main ligands and two triphenylphosphine as co-ligands with compositions [Cu{(P(C6H5)3}2(2-Py-CH2OCS2)] (2PyCu), [Cu{(P(C6H5)3}2(3-Py-CH2OCS2)] (3PyCu) and [Cu{(P(C6H5)3}2(4-Py-CH2OCS2)] (4PyCu) (Py = Pyridyl) are reported herein. The single crystal X-ray diffraction investigations for all three complexes suggest a distorted tetrahedral geometry around Cu(I) that is satisfied by two S centers of methylpyridyldithiocarbonate ligand in bidentate chelating mode and two PPh3 phosphorus centers. All three complexes exhibits interesting supramolecular frameworks sustained by C∙∙∙H, O∙∙∙H, S∙∙∙H and N∙∙∙H non-covalent interactions. The nature of these interactions have been assessed with the aid of Hirshfeld surface analyses and energy framework calculations. These complexes have been employed as molecular heterogeneous electrocatalysts in the oxygen/hydrogen evolution reactions (O/HERs). The electrocatalytic results indicate that 2PyCu exhibits the best electrocatalytic performance with onset potential of 1.67 V, η10 of 705.5 mV and a Tafel slope of 220 mV·dec‑1 for OER. For HER also 2PyCu displays superior performance with an onset potential, η10, and a Tafel slope of -0.507 V, -658 mV and 168 mV·dec‑1, respectively. Overall, because of the presence of Cu(I)-center, the electrocatalytic HER performances of all three complexes have been observed to be superior than their corresponding electrocatalytic OER performances.</p
Probing the effect of isomeric -OH group in heteroleptic Copper(I)-triphenylphosphine appended dithiocarbamates on their electrocatalytic properties for homogeneous hydrogen evolution reactions
No full textDue to increasing interest in alternative cost-effective electrocatalysts containing transition metals, three new heteroleptic triphenylphenylphosphine appended copper(I) dithiocarbamate complexes [Cu(S2CN(CH2C6H5)(CH2C6H4-o-OH))(PPh3)2] (Cu-o-OH), [Cu(S2CN(CH2C6H5)(CH2C6H4-m-OH))(PPh3)2] (Cu-m-OH) and [Cu(S2CN(CH2C6H5)(CH2C6H4-p-OH))(PPh3)2] (Cu-p-OH), have been synthesized, characterized spectroscopically and by single crystal X-ray diffraction. The single crystal X-ray studies suggest that for Cu-o-OH and Cu-m-OH, copper(I) possess a distorted P2S2 coordinate tetrahedral geometry. The solid-state framework of Cu-o-OH has been found to be majorly stabilized by O-H···S intermolecular interactions, while that of Cu-m-OH is sustained by C-H···C and O-H···S interactions, whose nature has been assessed by Hirshfeld surface analysis. The homogeneous electrocatalytic properties of the complexes for proton reduction reveal that the icat/iPc values of complexes are greater than 28, while utilizing trifluoroacetic acid (TFA) as a proton source. In all complexes, the ratio ic/iwc have been found to be greater than 1, indicating that these complexes can effectively catalyze proton reduction to hydrogen in acetonitrile. Amongst all the three complexes, Cu-p-OH has been found to be the best electrocatalyst with low overpotential (η) of 0.876 V and a highest turnover frequency (TOF) of 539.60 s−1 on adding 70 mM TFA. The best catalytic activity of Cu-p-OH has been attributed to its larger HOMO-LUMO energy gap and a more positive charge on copper(I) compared to other isomeric complexes that assists the complex to attract more electron density that could have readily enhanced its electrocatalytic performance.</p
Homoleptic nickel(II)-dithiocarbamates as potent homogeneous electrocatalysts for hydrogen evolution reaction:Effect of positional isomeric –OH group on electrocatalytic properties
No full textThree positional isomeric homoleptic Ni(II) dithiocarbamate complexes having general formula [Ni(L)2] (L=N-benzyl-1-(2-hydroxyphenyl) dithiocarbamate (Ni-1); N-benzyl-1-(3-hydroxyphenyl) dithiocarbamate (Ni-2) and N-benzyl-1-(4-hydroxyphenyl) dithiocarbamate (Ni-3)) have been synthesized and characterized by elemental analysis, FT-IR, UV–Vis., multinuclear NMR spectroscopy and single crystal X-ray diffraction. The single crystal X-ray analysis for Ni-2 reveals distorted square planar geometry around Ni(II), that is satisfied by four sulfur centers of two N-benzyl-1-(3-hydroxyphenyl) dithiocarbamate ligands. The nature of weak interactions in Ni-2 have been explored using Hirshfeld surface analysis, which suggest that the percentage contribution of O···H interactions is more than S···H interactions. These complexes have been employed as homogeneous catalysts for electrochemical hydrogen evolution reaction suggesting turnover frequency (TOF) of 566.2, 457.2 and 867.9 s−1 for Ni-1, Ni-2 and Ni-3, respectively on adding 30 mM trifluoroacetic acid (TFA). Also, the overpotential (η) values for Ni-1, Ni-2 and Ni-3 are 0.862, 0.872 and 0.723 V, respectively. The variation in the electrocatalytic properties was explained on the basis of theoretical calculations which suggested that the para-OH isomer complex possess relatively larger HOMO-LUMO energy gap, compared to ortho-OH and meta-OH isomeric complexes and indicated the relative less stable nature of para-OH isomer complex and its better susceptibility towards electrons at a lower negative potential.</p
