24 research outputs found

    Evaluating the Effect of Woodchips on Soil Matric Potential, Temperature, Weed Biomass, and Yield of Selected Crops

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    Organic mulches are very popular for weed control in sustainable agricultural systems where the application of synthetic herbicides is restricted. A study was conducted to evaluate the effectiveness of organic mulch in controlling weeds, enhancing soil matric potential, and soil temperature. Blended hardwood mulch was applied to the soil surface at a thickness of 10 cm. The experimental design was laid out as a completely randomized design with two treatments, viz., mulch and no-mulch, replicated 5 times. Data were collected during the growing period for weed biomass, soil matric potential, soil temperature, and yield of selected crops. Results from a two-way ANOVA revealed that the mulch treatments significantly (p≤0.50) reduced weed biomass, and soil temperature while increasing the soil matric potential and yields of okra, tomatoes, squash, and basil. It was concluded that the use of organic mulch was beneficial for weed control and increasing crop yield

    Evaluating the Impact of Nitrogen Fertilization Treatments and Irrigation on Soil Health Indicators in a Long-Term Crop Rotation Research Plot

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    Abstract Many agriculturalists have been focusing on the most efficient farming method that would produce the maximum yield while still sustaining the soil ecosystem. Soil samples were collected from the “Old Rotation” area (Auburn University, Auburn, AL), and were assessed for soil biochemical, chemical and biological characteristics related to soil quality. Treatments of the experimental site were a control with no legumes or N fertilizer; cotton every year with winter legumes; a 3-yr cotton-corn-soybean rotation with wheat and winter legumes; and cotton every year with N fertilizer. Impacts of irrigation were also tested between the sites. Assays were performed measuring phosphomonoesterase and phosphodiesterase activity, soil organic carbon, soil pH, and microbial diversity. The 3-year and winter legume rotations showed significant differences in the structure and membership of microbial communities and differences in biochemical activity. These results further demonstrate the ability of crop rotation to enhance the soil health of agricultural ecosystems. Keywords: Nitrogen Fertilization, Irrigation, Crop Rotation, Soil Ecology, Enzymatic Activit

    The Plasmodium falciparum Rh5 invasion protein complex reveals an excess of rare variant mutations.

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    BACKGROUND: The invasion of the red blood cells by Plasmodium falciparum merozoites involves the interplay of several proteins that are also targets for vaccine development. The proteins PfRh5-PfRipr-PfCyRPA-Pfp113 assemble into a complex at the apical end of the merozoite and are together essential for erythrocyte invasion. They have also been shown to induce neutralizing antibodies and appear to be less polymorphic than other invasion-associated proteins, making them high priority blood-stage vaccine candidates. Using available whole genome sequencing data (WGS) and new capillary sequencing data (CS), this study describes the genetic polymorphism in the Rh5 complex in P. falciparum isolates obtained from Kilifi, Kenya. METHODS: 162 samples collected in 2013 and 2014 were genotyped by capillary sequencing (CS) and re-analysed WGS from 68 culture-adapted P. falciparum samples obtained from a drug trial conducted from 2005 to 2007. The frequency of polymorphisms in the merozoite invasion proteins, PfRh5, PfRipr, PfCyRPA and PfP113 were examined and where possible polymorphisms co-occurring in the same isolates. RESULTS: From a total 70 variants, including 2 indels, 19 SNPs [27.1%] were identified by both CS and WGS, while an additional 15 [21.4%] and 36 [51.4%] SNPs were identified only by either CS or WGS, respectively. All the SNPs identified by CS were non-synonymous, whereas WGS identified 8 synonymous and 47 non-synonymous SNPs. CS identified indels in repeat regions in the p113 gene in codons 275 and 859 that were not identified in the WGS data. The minor allele frequencies of the SNPs ranged between 0.7 and 34.9% for WGS and 1.1-29.6% for CS. Collectively, 12 high frequency SNPs (> 5%) were identified: four in Rh5 codon 147, 148, 203 and 429, two in p113 at codons 7 and 267 and six in Ripr codons 190, 259, 524, 985, 1003 and 1039. CONCLUSION: This study reveals that the majority of the polymorphisms are rare variants and confirms a low level of genetic polymorphisms in all proteins within the Rh5 complex

    The Impact of Selected Socioeconomic Factors on Residents’ Perceptions of Benefits of Community Gardens

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    Participating in community gardens is believed to have several benefits; yet, there has been limited research on socioeconomic factors and their impact on community gardens. Therefore, this study assessed the impact of selected socioeconomic factors on residents’ perceptions of benefits of community gardens. Using a questionnaire, data were obtained from a convenience sample of 217 participants from Macon County, Alabama, and analyzed using descriptive statistics and ordinal logit analysis. The results showed that a majority (at least 73%) agreed or strongly agreed with statements regarding nutritional benefits, health benefits, and community benefits of community gardens. In addition, several socioeconomic factors; age, education, and annual household income, had statistically significant effects on perceptions of benefits of participating in community gardens. Consequently, it was recommended that policies and programs that encourage participation in community gardens be put in place for residents in the study area, with cooperation among, county officials, University scientists, and community residents. This will lead to benefits of eating more fruits and vegetables, eating fresher foods, and possibly, in the long-term, reducing chronic diseases. Keywords: Community gardens, Socioeconomic factors, Macon County, Rural communitie

    Optimization of the SARS-CoV-2 ARTIC network V4 primers and whole genome sequencing protocol

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    Introduction: The ARTIC Network's primer set and amplicon-based protocol is one of the most widely used SARS-CoV-2 sequencing protocol. An update to the V3 primer set was released on 18th June 2021 to address amplicon drop-off observed among the Delta variant of concern. Here, we report on an in-house optimization of a modified version of the ARTIC Network V4 protocol that improves SARS-CoV-2 genome recovery in instances where the original V4 pooling strategy was characterized by amplicon drop-offs. Methods: We utilized a matched set of 43 clinical samples and serially diluted positive controls that were amplified by ARTIC V3, V4 and optimized V4 primers and sequenced using GridION from the Oxford Nanopore Technologies'. Results: We observed a 0.5% to 46% increase in genome recovery in 67% of the samples when using the original V4 pooling strategy compared to the V3 primers. Amplicon drop-offs at primer positions 23 and 90 were observed for all variants and positive controls. When using the optimized protocol, we observed a 60% improvement in genome recovery across all samples and an increase in the average depth in amplicon 23 and 90. Consequently, ≥95% of the genome was recovered in 72% (n = 31) of the samples. However, only 60–70% of the genomes could be recovered in samples that had 0.05) correlation between Ct value and genome recovery. Conclusion: Utilizing the ARTIC V4 primers, while increasing the primer concentrations for amplicons with drop-offs or low average read-depth, greatly improves genome recovery of Alpha, Beta, Delta, Eta and non-VOC/non-VOI SARS-CoV-2 variants

    A new Omicron lineage with Spike Y451H mutation that dominated a new COVID-19 wave in Kilifi, Coastal Kenya : March-May 2023

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    Objective Assessment of the efficacy and safety/tolerability of the aromatase inhibitor leflutrozole to normalise testosterone in Obesity-associated Hypogonadotropic Hypogonadism (OHH). Design Placebo-controlled, double-blind, RCT, in 70 sites in Europe/USA. Methods Patient inclusion criteria: men with BMI of 30-50 kg/m2, morning total testosterone (TT) < 10.41 nmol/L, and two androgen deficiency symptoms (at least one of sexual dysfunction). Patients randomised to weekly leflutrozole (0.1/0.3/1.0 mg) or placebo for 24 weeks. Primary endpoint: normalisation of TT levels in ≥75% of patients after 24 weeks. Secondary endpoints (included): time to TT normalisation and change in LH/FSH. Safety was assessed through adverse events and laboratory monitoring. Results and Conclusions Of 2103 screened, 271 were randomised, 81 discontinued. Demographic characteristics were similar across groups. Mean BMI was 38.1 kg/m2 and TT 7.97 nmol/L. The primary endpoint was achieved in all leflutrozole-treated groups by 24 weeks with a dose-tiered response; mean TT 15.89; 17.78; 20.35 nmol/L, for leflutrozole 0.1 mg, 0.3 mg, and 1.0 mg groups respectively, vs 8.04 nmol/L for placebo. LH/FSH significantly increased in leflutrozole vs placebo groups. No improvements in body composition or sexual dysfunction were observed. Semen volume/total motile sperm count improved with leflutrozole vs placebo. Treatment-emergent adverse events, more common in leflutrozole-treated groups included, raised haematocrit, hypertension, increased PSA, and headache. Some reduction in lumbar bone density was observed with leflutrozole (mean −1.24%, −1.30%, −2.09%) and 0.66% for 0.1 mg, 0.3 mg, 1.0 mg, and placebo, respectively, without change at the hip. This RCT of leflutrozole in OHH demonstrated normalisation of TT in obese men. FSH/LH and semen parameter changes support that leflutrozole may preserve/improve testicular function

    Progress towards implementation of ACT malaria case-management in public health facilities in the Republic of Sudan: a cluster-sample survey

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    <p>Abstract</p> <p>Background</p> <p>Effective malaria case-management based on artemisinin-based combination therapy (ACT) and parasitological diagnosis is a major pillar within the 2007-2012 National Malaria Strategic Plan in the Sudan. Three years after the launch of the strategy a health facility survey was undertaken to evaluate case-management practices and readiness of the health facilities and health workers to implement a new malaria case-management strategy.</p> <p>Methods</p> <p>A cross-sectional, cluster sample survey was undertaken at public health facilities in 15 states of Sudan. Data were collected using quality-of-care assessment methods. The main outcomes were the proportions of facilities with ACTs and malaria diagnostics; proportions of health workers exposed to malaria related health systems support activities; and composite and individual indicators of case-management practices for febrile outpatients stratified by age, availability of ACTs and diagnostics, use of malaria diagnostics, and test result.</p> <p>Results</p> <p>We evaluated 244 facilities, 294 health workers and 1,643 consultations for febrile outpatients (425 < 5 years and 1,218 ≥ 5 years). Health facility and health worker readiness was variable: chloroquine was available at only 5% of facilities, 73% stocked recommended artesunate and sulfadoxine/pyrimethamine (AS+SP), 51% had the capacity to perform parasitological diagnosis, 53% of health workers had received in-service training on ACTs, 24% were trained in the use of malaria Rapid Diagnostic Tests, and 19% had received a supervisory visit including malaria case-management. At all health facilities 46% of febrile patients were parasitologically tested and 35% of patients were both, tested and treated according to test result. At facilities where AS+SP and malaria diagnostics were available 66% of febrile patients were tested and 51% were both, tested and treated according to test result. Among test positive patients 64% were treated with AS+SP but 24% were treated with artemether monotherapy. Among test negative patients only 17% of patients were treated for malaria. The majority of ACT dispensing and counseling practices were suboptimal.</p> <p>Conclusions</p> <p>Five years following change of the policy from chloroquine to ACTs and 3 years before the end of the new malaria strategic plan chloroquine was successfully phased out from public facilities in Sudan, however, an important gap remained in the availability of ACTs, diagnostic capacities and coverage with malaria case-management activities. The national scale-up of diagnostics, using the findings of this survey as well as future qualitative research, should present an opportunity not only to expand existing testing capacities but also to implement effective support interventions to bridge the health systems gaps and support corrective case-management measures, including the discontinuation of artemether monotherapy treatment.</p

    Randomized controlled field trial to assess the immunogenicity and safety of rift valley fever clone 13 vaccine in livestock

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    BACKGROUND:Although livestock vaccination is effective in preventing Rift Valley fever (RVF) epidemics, there are concerns about safety and effectiveness of the only commercially available RVF Smithburn vaccine. We conducted a randomized controlled field trial to evaluate the immunogenicity and safety of the new RVF Clone 13 vaccine, recently registered in South Africa. METHODS:In a blinded randomized controlled field trial, 404 animals (85 cattle, 168 sheep, and 151 goats) in three farms in Kenya were divided into three groups. Group A included males and non-pregnant females that were randomized and assigned to two groups; one vaccinated with RVF Clone 13 and the other given placebo. Groups B included animals in 1st half of pregnancy, and group C animals in 2nd half of pregnancy, which were also randomized and either vaccinated and given placebo. Animals were monitored for one year and virus antibodies titers assessed on days 14, 28, 56, 183 and 365. RESULTS:In vaccinated goats (N = 72), 72% developed anti-RVF virus IgM antibodies and 97% neutralizing IgG antibodies. In vaccinated sheep (N = 77), 84% developed IgM and 91% neutralizing IgG antibodies. Vaccinated cattle (N = 42) did not develop IgM antibodies but 67% developed neutralizing IgG antibodies. At day 14 post-vaccination, the odds of being seropositive for IgG in the vaccine group was 3.6 (95% CI, 1.5 - 9.2) in cattle, 90.0 (95% CI, 25.1 - 579.2) in goats, and 40.0 (95% CI, 16.5 - 110.5) in sheep. Abortion was observed in one vaccinated goat but histopathologic analysis did not indicate RVF virus infection. There was no evidence of teratogenicity in vaccinated or placebo animals. CONCLUSIONS:The results suggest RVF Clone 13 vaccine is safe to use and has high (>90%) immunogenicity in sheep and goats but moderate (> 65%) immunogenicity in cattle

    Epidemiology of COVID-19 infections on routine polymerase chain reaction (PCR) and serology testing in Coastal Kenya [version 1; peer review: 2 approved]

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    Background: There are limited studies in Africa describing the epidemiology, clinical characteristics and serostatus of individuals tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We tested routine samples from the Coastal part of Kenya between 17th March 2020 and 30th June 2021. Methods: SARS-CoV-2 infections identified using reverse transcription polymerase chain reaction (RT-PCR) and clinical surveillance data at the point of sample collection were used to classify as either symptomatic or asymptomatic. IgG antibodies were measured in sera samples, using a well validated in-house enzyme-linked immunosorbent assay (ELISA). Results: Mombasa accounted for 56.2% of all the 99,694 naso-pharyngeal/oro-pharyngeal swabs tested, and males constituted the majority tested (73.4%). A total of 7737 (7.7%) individuals were SARS-CoV-2 positive by RT-PCR. The majority (i.e., 92.4%) of the RT-PCR positive individuals were asymptomatic. Testing was dominated by mass screening and travellers, and even at health facility level 91.6% of tests were from individuals without symptoms. Out of the 97,124 tests from asymptomatic individuals 7,149 (7%) were positive and of the 2,568 symptomatic individuals 588 (23%) were positive. In total, 2458 serum samples were submitted with paired naso-pharyngeal/oro-pharyngeal samples and 45% of the RT-PCR positive samples and 20% of the RT-PCR negative samples were paired with positive serum samples. Symptomatic individuals had significantly higher antibody levels than asymptomatic individuals and become RT-PCR negative on repeat testing earlier than asymptomatic individuals. Conclusions: In conclusion, the majority of SARS-CoV-2 infections identified by routine testing in Coastal Kenya were asymptomatic. This reflects the testing practice of health services in Kenya, but also implies that asymptomatic infection is very common in the population. Symptomatic infection may be less common, or it may be that individuals do not present for testing when they have symptoms
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