85 research outputs found
Aspergillus species colonization of termite-damaged peanuts in parts of West Africa and its control prospects
A survey of farmers' peanut fields in Benin showed
that Aspergillus flavus Link ex Fries infection was influenced by Microtermes (Isoptera: Termitidae) damage.
Field trials conducted at the ICRISAT station and a
farmer's plot in Mali on termite damage and Aspergillus
spp. infection showed that peanut plots treated with
carbofuran at planting and supplemented with chlorpyrifos
at 40 days after planting (dap), or treated with only
chlorpyrifos at 40 dap, significantly reduced pod damage
by the termite M. lepidus Sjostedt. and colonization by
A. flavus. The cultivar ICG 10946 which had significantly
more A. flavus (P < 0.05) also had a higher percentage of damaged pods compared with tlle other cultivars at the on-station trials. The least infected cultivar in all the trials was 47-16 which also had a comparatively
lower percentage of termite-damaged pods, although
this was not Significant. However, termite damage
was correlated with A. flavus percentage colonizatio
Soil pests of groundnut in West Africa - species diversity, damage and estimation of yield losses
Among the major arthropods in soil and plant samples taken from groundnut farms during the 1996 cropping season in Mali, Burkina-Faso, Niger, and Nigeria, termites in the genus Microtermes (Isoptera: Termitidae) were the most abundant and widely distributed species of economic importance. None of the termite species identified on trees in the surveyed farms attacked groundnuts. At plant maturity, termites were less frequently observed in soils taken from bare ground but were predominantly found on plants. Residues of previous cereal crops in the fields contributed to termite spread. Most of the whitegrub (Coleoptera: Scarabaeidae) and millipede (Myriapoda: Odontopygidae) species identified belonged to the genera of Schyzonycha and Peridontopyge, respectively. There was a general decrease in both their population densities and the percentages of farms they infested at plant maturity compared to the early stages of the crop. Mean percentages of plants attacked by termites, whitegrubs and millipedes in the surveyed groundnut fields were 39.4, 10.9, and 9.3%, respectively. Yield loss due to termites, which predominantly damaged harvested kernels, was estimated at 9.6-30.4%, and was significantly correlated with percentage of plants damaged by termites (r²=0.73
Non-perturbative results for the luminosity and area distances
The notion of luminosity distance is most often defined in purely FLRW (Friedmann-Lemaitre-Robertson-Walker) cosmological spacetimes, or small perturbations thereof. However, the abstract notion of luminosity distance is actually much more robust than this, and can be defined non-perturbatively in almost arbitrary spacetimes. Some quite general results are already known, in terms of dAobserver/d\u3a9source, the cross-sectional area per unit solid angle of a null geodesic spray emitted from some source and subsequently detected by some observer. We shall reformulate these results in terms of a suitably normalized null geodesic affine parameter and the van Vleck determinant, \u394vV. The contribution due to the null geodesic affine parameter is effectively the inverse square law for luminosity, and the van Vleck determinant can be viewed as providing a measure of deviations from the inverse square law. This formulation is closely related to the so-called Jacobi determinant, but the van Vleck determinant has somewhat nicer analytic properties and wider and deeper theoretical base in the general relativity, quantum physics, and quantum field theory communities. In the current article we shall concentrate on non-perturbative results, leaving near-FLRW perturbative investigation for future work
Prevalence and distribution of aflatoxin contamination in groundnut (Arachis hypogaea L.) in Mali, West Africa
Groundnut is a major source of livelihood for the rural poor in Mali. However, the crop is prone to preand
post-harvest aflatoxin contamination caused by Aspergillus flavus and Aspergillus parasiticus.
Therefore, to minimize health related hazards from exposure to aflatoxin contaminated food, information
on the prevalence and distribution of aflatoxins (AFB1) in the groundnut value chain in Mali is needed for
timely interventions. To this end, a study was undertaken in three districts (Kayes, Kita and Kolokani) to
assess aflatoxin contamination in the field and storage. Ninety pod samples in each district were
collected from fields (30 villages/district and 3 samples/village) during 2009 and 2010. Pre-harvest
contamination was estimated at harvest, whereas samples for post-harvest contamination were
collected from granaries of the same farmers at a monthly interval for 3 months. The villages in each
district were categorized into safe, acceptable, moderate risk and high risk areas based on pre-harvest
AFB1 levels. Kayes recorded more pod samples (77%) within 20 mg/kg of pre-harvest aflatoxins followed
by Kolokani (55.6%) and Kita (45.6%) based on 2009 and 2010 mean values. Toxin concentrations at
harvest were comparatively less in Kayes during both years. Further, Kayes had more villages under safe
and acceptable limits when compared to Kolokani and Kita. Overall, 46 out of 90 villages in the three
districts had acceptable pre-harvest toxin limits. Further, 12 villages in Kolokani were in the high risk
category. An increase in toxin levels was noticed with period of storage during both years. Comparatively,
toxin levels after storage were least in Kayes during 2009. Kayes also recorded less AFB1 levels in 2010
after Kita. Our results indicate that Kayes is relatively safe over Kita and Kolokani in pre-harvest aflatoxin
contamination. The reasons for district-wide variations in pre-harvest contamination; and the reasons
for post-harvest flare up of the problem are discussed. Further, proper storage of pods at farmers' granaries
in Mali is suggested to overcome the problem from reaching alarming levels
How does the cosmic large-scale structure bias the Hubble diagram?
The Hubble diagram is one of the cornerstones of observational cosmology. It
is usually analysed assuming that, on average, the underlying relation between
magnitude and redshift matches the prediction of a
Friedmann-Lema\^itre-Robertson-Walker model. However, the inhomogeneity of the
Universe generically biases these observables, mainly due to peculiar
velocities and gravitational lensing, in a way that depends on the notion of
average used in theoretical calculations. In this article, we carefully derive
the notion of average which corresponds to the observation of the Hubble
diagram. We then calculate its bias at second-order in cosmological
perturbations, and estimate the consequences on the inference of cosmological
parameters, for various current and future surveys. We find that this bias
deeply affects direct estimations of the evolution of the dark-energy equation
of state. However, errors in the standard inference of cosmological parameters
remain smaller than observational uncertainties, even though they reach percent
level on some parameters; they reduce to sub-percent level if an optimal
distance indicator is used.Comment: 19+7 pages, 10 figures, v2 accepted by JCAP; minor changes to improve
clarit
Chlorproguanil−Dapsone−Artesunate versus Artemether−Lumefantrine: A Randomized, Double-Blind Phase III Trial in African Children and Adolescents with Uncomplicated Plasmodium falciparum Malaria
Chlorproguanil−dapsone−artesunate (CDA) was developed as an affordable, simple, fixed-dose artemisinin-based combination therapy for use in Africa. This trial was a randomized parallel-group, double-blind, double-dummy study to compare CDA and artemether−lumefantrine (AL) efficacy in uncomplicated Plasmodium falciparum malaria and further define the CDA safety profile, particularly its hematological safety in glucose-6-phosphate dehydrogenase (G6PD) -deficient patients
Hepatic profile analyses of tipranavir in Phase II and III clinical trials
<p>Abstract</p> <p>Background</p> <p>The risk and course of serum transaminase elevations (TEs) and clinical hepatic serious adverse event (SAE) development in ritonavir-boosted tipranavir (TPV/r) 500/200 mg BID recipients, who also received additional combination antiretroviral treatment agents in clinical trials (TPV/r-based cART), was determined.</p> <p>Methods</p> <p>Aggregated transaminase and hepatic SAE data through 96 weeks of TPV/r-based cART from five Phase IIb/III trials were analyzed. Patients were categorized by the presence or absence of underlying liver disease (+LD or -LD). Kaplan-Meier (K-M) probability estimates for time-to-first US National Institutes of Health, Division of AIDS (DAIDS) Grade 3/4 TE and clinical hepatic SAE were determined and clinical actions/outcomes evaluated. Risk factors for DAIDS Grade 3/4 TE were identified through multivariate Cox regression statistical modeling.</p> <p>Results</p> <p>Grade 3/4 TEs occurred in 144/1299 (11.1%) patients; 123/144 (85%) of these were asymptomatic; 84% of these patients only temporarily interrupted treatment or continued, with transaminase levels returning to Grade ≤ 2. At 96 weeks of study treatment, the incidence of Grade 3/4 TEs was higher among the +LD (16.8%) than among the -LD (10.1%) patients. K-M analysis revealed an incremental risk for developing DAIDS Grade 3/4 TEs; risk was greatest through 24 weeks (6.1%), and decreasing thereafter (>24-48 weeks: 3.4%, >48 weeks-72 weeks: 2.0%, >72-96 weeks: 2.2%), and higher in +LD than -LD patients at each 24-week interval. Treatment with TPV/r, co-infection with hepatitis B and/or C, DAIDS grade >1 TE and CD4<sup>+ </sup>> 200 cells/mm<sup>3 </sup>at baseline were found to be independent risk factors for development of DAIDS Grade 3/4 TE; the hazard ratios (HR) were 2.8, 2.0, 2.1 and 1.5, respectively. Four of the 144 (2.7%) patients with Grade 3/4 TEs developed hepatic SAEs; overall, 14/1299 (1.1%) patients had hepatic SAEs including six with hepatic failure (0.5%). The K-M risk of developing hepatic SAEs through 96 weeks was 1.4%; highest risk was observed during the first 24 weeks and decreased thereafter; the risk was similar between +LD and -LD patients for the first 24 weeks (0.6% and 0.5%, respectively) and was higher for +LD patients, thereafter.</p> <p>Conclusion</p> <p>Through 96 weeks of TPV/r-based cART, DAIDS Grade 3/4 TEs and hepatic SAEs occurred in approximately 11% and 1% of TPV/r patients, respectively; most (84%) had no significant clinical implications and were managed without permanent treatment discontinuation. Among the 14 patients with hepatic SAE, 6 experienced hepatic failure (0.5%); these patients had profound immunosuppression and the rate appears higher among hepatitis co-infected patients. The overall probability of experiencing a hepatic SAE in this patient cohort was 1.4% through 96 weeks of treatment. Independent risk factors for DAIDS Grade 3/4 TEs include TPV/r treatment, co-infection with hepatitis B and/or C, DAIDS grade >1 TE and CD4<sup>+ </sup>> 200 cells/mm<sup>3 </sup>at baseline.</p> <p>Trial registration</p> <p>US-NIH Trial registration number: NCT00144170</p
Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.
BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700
Twelve-month observational study of children with cancer in 41 countries during the COVID-19 pandemic
Introduction Childhood cancer is a leading cause of death. It is unclear whether the COVID-19 pandemic has impacted childhood cancer mortality. In this study, we aimed to establish all-cause mortality rates for childhood cancers during the COVID-19 pandemic and determine the factors associated with mortality. Methods Prospective cohort study in 109 institutions in 41 countries. Inclusion criteria: children <18 years who were newly diagnosed with or undergoing active treatment for acute lymphoblastic leukaemia, non-Hodgkin's lymphoma, Hodgkin lymphoma, retinoblastoma, Wilms tumour, glioma, osteosarcoma, Ewing sarcoma, rhabdomyosarcoma, medulloblastoma and neuroblastoma. Of 2327 cases, 2118 patients were included in the study. The primary outcome measure was all-cause mortality at 30 days, 90 days and 12 months. Results All-cause mortality was 3.4% (n=71/2084) at 30-day follow-up, 5.7% (n=113/1969) at 90-day follow-up and 13.0% (n=206/1581) at 12-month follow-up. The median time from diagnosis to multidisciplinary team (MDT) plan was longest in low-income countries (7 days, IQR 3-11). Multivariable analysis revealed several factors associated with 12-month mortality, including low-income (OR 6.99 (95% CI 2.49 to 19.68); p<0.001), lower middle income (OR 3.32 (95% CI 1.96 to 5.61); p<0.001) and upper middle income (OR 3.49 (95% CI 2.02 to 6.03); p<0.001) country status and chemotherapy (OR 0.55 (95% CI 0.36 to 0.86); p=0.008) and immunotherapy (OR 0.27 (95% CI 0.08 to 0.91); p=0.035) within 30 days from MDT plan. Multivariable analysis revealed laboratory-confirmed SARS-CoV-2 infection (OR 5.33 (95% CI 1.19 to 23.84); p=0.029) was associated with 30-day mortality. Conclusions Children with cancer are more likely to die within 30 days if infected with SARS-CoV-2. However, timely treatment reduced odds of death. This report provides crucial information to balance the benefits of providing anticancer therapy against the risks of SARS-CoV-2 infection in children with cancer
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