Retino-hypothalamic regulation of light-induced murine sleep

The temporal organization of sleep is regulated by an interaction between the circadian clock and homeostatic processes. Light indirectly modulates sleep through its ability to phase shift and entrain the circadian clock. Light can also exert a direct, circadian-independent effect on sleep. For example, acute exposure to light promotes sleep in nocturnal animals and wake in diurnal animals. The mechanisms whereby light directly influences sleep and arousal are not well understood. In this review, we discuss the direct effect of light on sleep at the level of the retina and hypothalamus in rodents. We review murine data from recent publications showing the roles of rod-, cone- and melanopsin-based photoreception on the initiation and maintenance of light-induced sleep. We also present hypotheses about hypothalamic mechanisms that have been advanced to explain the acute control of sleep by light. Specifically, we review recent studies assessing the roles of the ventrolateral preoptic area (VLPO) and the suprachiasmatic nucleus (SCN). We also discuss how light might differentially promote sleep and arousal in nocturnal and diurnal animals respectively. Lastly, we suggest new avenues for research on this topic which is still in its early stages

Effects of Culture Conditions on Growth of Kefir Grains using Milk for Nutrition and Health: An Application of Response Surface Methodoly with Box-behnken Design.

This combined process was successfully modeled by response surface methodology method with a Box–Behnken design. In this work, Box-Behnken Design of response surface methodology was used to investigate the effects of fat content in milk, incubation time and the number of rotations or shaking as culture conditions to for  growing kefir grains using milk as culture liquid. The implementation of first order factorial experiment was based on a 3k Box- Benhnken experimental factorial design with one replicate. Response surface methodology was adopted to express the output parameter (Size of the kefir grain) that is decided by the input parameters (Number of rotations, Time and milk fat content) which yielded the response surface models. The effects of the culture conditions on growth of kefir grains using milk was studied by use of first order model. The adequacy of the first order model was examined by use residual analysis, the normal plot, the main affects plots, the contour plot, and ANOVA statistics F-test, t-test, R2, and the adjusted R. The optimization of culture conditions was achieved by the help of the steepest ascent method to locate the optimal domain and direction of growth of kefir grains. The first order model was predicted using a D-optimal criterion which was used to evaluate the growth of kefir grains. The confidence level to check the growth of kefir grain was at 95%. The data was analyzed using R statistical software and excel. Data was presented using tables and graphs. Milk fat content and number of rotations per minute had a positive effects  while time had a negative effects on the growth of kefir grains using milk. Keywords: Kefir grains; Response Surface Methodology; Box-behnken design; Culture condition

Survey of Nematode-Destroying Fungi from Selected Vegetable-Growing Areas in Kenya

Plant-parasitic nematodes cause severe damage to a wide range of economic crops, causing upto 5% yield losses globally. In Kenya, vegetables are affected, among other pests, by parasitic nematodes, causing upto 80% loss in yield. Nematode control is very difficult and relies heavily on use of chemical nematicides. Use of these chemical nematicides leads to biological magnification, and elimination of natural enemies of other pathogens, thus creating a need for greater application of pesticides, increased production costs, and development of insecticide-resistance. These factors have led to a growing interest in search for alternate management strategies. The objective of this study was, therefore, to document nematode-destroying fungi in selected, major vegetable-growing areas in Kenya as a step towards developing a self-sustaining system for management of plant-parasitic nematodes. Soil samples were collected from five vegetable-production zones, viz., Kinare, Kabete, Athi-river, Machakos and Kibwezi, and transported to the laboratory for extraction of nematode-destroying fungi. The soil-sprinkle technique described by Jaffee et al (1996) was used for isolating the nematode-destroying fungi from soil, while, their identification was done using identification keys described by Soto Barrientos et al (2001). From this study, a total of 171 fungal isolates were identified as nematodedestroying. The highest population was recorded in Kabete, at 33.9% of the total, followed by Machakos, Kibwezi, Athi-river, with the least in Kinare, at 24.6, 22.2, 11.7 and 7.6% of the total population, in that order. Arthrobotrys was the most frequent genus, with mean occurrence of 7.3, followed by Monacrosporium with 6 and Stylophage with 5.2. A. dactyloides was significantly (P=0.002) affected by the agro-ecological zone, with the highest occurrence recorded in Kabete, and the least in Athi-river. Kibwezi recorded highest diversity index, with a mean of 1.017, while, Athi-river recorded the least, with a mean of 0.333. Kibwezi had the highest species richness, recording a mean of 3.4, while, the least mean of 1.6 was recorded in Athi-river. Mean species richness of 2.2 was recorded for both Kabete and Machakos, and 1.8 for Kinare. From the three genera recorded, Arthrobotrys was more effective at trapping nematodes compared to Monocrosporium and Stylopage. The genus Arthrobotrys had the highest number of trapped nematodes, with a total population of 57, followed by Monacrosporium, the least being Stylopage, with 45 and 36, respectively, in a period of 104 hours. From the study, it is evident that agricultural practices affect occurrence and diversity of nematodedestroying fungi, and, Arthrobotrys can be used as a bio-control agent for managing plant-parasitic nematodes

Can I speak to the manager? The gender dynamics of decision-making in Kenyan maize plots

Gender and social inclusion efforts in agricultural development are focused on making uptake of agricultural technologies more equitable. Yet research looking at how gender relations influence technology uptake often assumes that men and women within a household make farm management decisions as individuals. Relatively little is understood about the dynamics of agricultural decision-making within dual-adult households where individuals’ management choices are likely influenced by others in the household. This study used vignettes to examine decision-making related to maize plot management in 698 dual-adult households in rural Kenya. The results indicated a high degree of joint management of maize plots (55%), although some management decisions—notably those related to purchased inputs—were slightly more likely to be controlled by men, while other decisions—including those related to hiring of labor and maize end uses—were more likely to be made by women. The prevalence of joint decision-making underscores the importance of ensuring that both men’s and women’s priorities and needs are reflected in design and marketing of interventions to support maize production, including those related to seed systems, farmer capacity building, and input delivery