First delivery of a COVID-19 positive patient in Cameroon

Since its appearance in China in December 2019, COVID-19 which is caused by the SARS-CoV-2 virus has become a real global health problem. Pregnant women are not immune to this novel infection, which makes it difficult for proper management of pregnancy and childbirth. Authors present here the first case of childbirth in Cameroon of a 19-year-old adolescent tested positive for COVID-19

Effect of hysteresis on water flow in the vadose zone under natural boundary conditions, Siloam Village case study, South Africa

A one-dimensional vadose zone model was used to simulate flow under natural boundary conditions. The effects of hysteresis and temporal variability of meteorological conditions were evaluated. Simulations were performed in HYDRUS-1D code for the period April 2013–January 2014 (6601 hours) at three different locations in a delineated portion of the sub-quaternary catchment A80A of Nzhelele with different soil textures. Soil hydraulic characteristics were estimated in a Rosetta library dynamically linked to the HYDRUS-1D model which is based on the numerical solution of a one-dimensional Richard’s equation. Analysis of the simulation results suggests that ignoring hysteresis for soils of similar textural class does not lead to any significant deviation of the model predicted soil moisture, unlike for soils with different textural classesResearch and Publications Committee (RPC) which is under the Directorate of Research and Innovation of the University of Venda, South Afric

Vadose zone infiltration and its implication for groundwater contamination risk assessment in Siloam village, Limpopo province, South Africa

Risk assessment methods and approaches are useful for environmental planning and decision-making when dealing with risk identification and reduction in a changing global context. This is particularly true for arid and semi-arid regions, such as Siloam village, Limpopo province, South Africa, where it is a common practice to apply fertilisers to the soil during planting season for increasing crop yield. Estimates of vadose zone soil moisture fluxes were used to determine the likelihood of applied agricultural fertilisers to reach the groundwater table. This study combines field observations in the study area and a one-dimensional numerical model to explore the moisture fluxes and their implications for contaminant transport in the vadose zone. Model simulations revealed a lag time of 117 days at topsoil and 913 days beyond the root zone for deep percolation of soluble non-reactive inorganic and organic additives to reach the groundwater table. Preliminary results of this study suggest that the vadose zone is permeable and the groundwater is vulnerable to contamination within the evaluated time scale. Given that disaster risks are inevitable, reasonable methods for control and mitigation of agricultural impacts at this site are highly recommended

Vadose zone infiltration and its implication for groundwater contamination risk assessment in Siloam village, Limpopo province, South Africa

Risk assessment methods and approaches are useful for environmental planning and decision-making when dealing with risk identification and reduction in a changing global context. This is particularly true for arid and semi-arid regions, such as Siloam village, Limpopo province, South Africa, where it is a common practice to apply fertilisers to the soil during planting season for increasing crop yield. Estimates of vadose zone soil moisture fluxes were used to determine the likelihood of applied agricultural fertilisers to reach the groundwater table. This study combines field observations in the study area and a one-dimensional numerical model to explore the moisture fluxes and their implications for contaminant transport in the vadose zone. Model simulations revealed a lag time of 117 days at topsoil and 913 days beyond the root zone for deep percolation of soluble non-reactive inorganic and organic additives to reach the groundwater table. Preliminary results of this study suggest that the vadose zone is permeable and the groundwater is vulnerable to contamination within the evaluated time scale. Given that disaster risks are inevitable, reasonable methods for control and mitigation of agricultural impacts at this site are highly recommended.</jats:p

Inheritance of resistance to Cercospora leaf spot disease of cowpea [Vigna unguiculata (L.) Walp]

AbstractCercospora leaf spot (CLS) caused by Pseudocercospora cruenta (Sacc.) is an important disease affecting cowpea production in Nigeria. Understanding the genetic nature of CLS is an important step in developing an effective breeding strategy. This study investigated the inheritance of CLS disease in cowpea under natural epiphytotic field condition involving two CLS resistant parents (IT99K-573-1-1, IT99K216-24) and a CLS susceptible parent (UAM09-1055-6). The parental lines, F1, BC1P1, BC1P2, F2 and F3 generations were used to study the genetic nature and to detect SSR markers closely linked with the CLS resistance gene(s) using bulked segregant analysis (BSA). The result showed that F1 populations involving UAM09-1055-6 × IT99K-573-1-1 and UAM09-1055-6 × IT99K-216-24 were resistant to CLS in the 2 crosses suggesting the presence of gene dominance in the control of the disease. The observed segregating ratio of F2 populations fits the Mendalian ratio 3:1. The plants reaction to the disease in the backcross progeny test involving the resistant parent were all uniformly resistant, whereas those involving the susceptible parent segregated into ratio 1:1. The F3 generations, which segregated into ratio 1:2:1 further confirmed that resistance was controlled by a single dominant gene in the crosses studied. Heritability estimates varied from 81 to 97%. BSA showed that SSR marker code named RB24 of lima bean and validated on F2 population discriminated between resistance and susceptibility to CLS. Hence RB24 could be a useful marker for marker-assisted selection in CLS resistance breeding in cowpea.</jats:p

Human NK cells of mice with reconstituted human immune system components require pre-activation to acquire functional competence

To investigate human natural killer (NK)– cell reactivity in vivo we have reconstituted human immune system components by transplantation of human hematopoietic progenitor cells into NODscid IL2Rnull mice. We demonstrate here that this model allows the development of all NK-cell subsets that are also found in human adult peripheral and cord blood, including NKp46CD56 NK cells. Similar to human cord blood, NK cells from these reconstituted mice require preactivation by interleukin-15 to reach the functional competence of human adult NK cells. Mainly the terminally differentiated CD16 NK cells demonstrate lower reactivity without this stimulation. After preactivation, both CD16 and CD16 NK cells efficiently produce interferon- and degranulate in response to stimulation with NK cell–susceptible targets, including K562 erythroleukemia cells. NK-cell lines, established from reconstituted mice, demonstrate cytotoxicity against this tumor cell line. Importantly, preactivation can as well be achieved by bystander cell maturation via poly I:C stimulation in vitro and injection of this maturation stimulus in vivo. Preactivation in vivo enhances killing of human leukocyte antigen class I negative tumor cells after their adoptive transfer. These data suggest that a functional, but resting, NK-cell compartment can be established in immune-compromised mice after human hematopoietic progenitor cell transfer