Dynamics of depolarization and hyperpolarization in the frontal cortex and saccade goal

The frontal eye field and neighboring area 8Ar of the primate cortex are involved in programming and execution of saccades. Electrical microstimulation in these regions elicits short-latency contralateral saccades. To determine how spatiotemporal dynamics of microstimulation-evoked activity are converted into saccade plans, we used a combination of real-time optical imaging and microstimulation in behaving monkeys. Short stimulation trains evoked a rapid and widespread wave of depolarization followed by unexpected large and prolonged hyperpolarization. During this hyperpolarization saccades are almost exclusively ipsilateral, suggesting an important role for hyperpolarization in determining saccade goal.     

Productivity and profitability of maize-legume cropping systems under conservation agriculture among smallholder farmers in Malawi

ABSTRACT

A study was conducted from 2014 to 2017 in Malawi to elucidate the short-term effects of maize-legume intercropping and rotation systems under conservation agriculture (CA) and conventional tillage (CT) on crop productivity and profitability. Twelve farmers hosted on-farm trials per district, in three districts, with each farmer having six plots. The design of the study was randomised complete block design arranged in a split plot fashion with tillage as main plot and cropping systems as sub-plots, with each farmer acting as a replicate. CA had 1400 and 3200 kg ha^?1 more maize grain yield in the second and third seasons, respectively compared with CT. In the first two seasons, CT had 310, 180 and 270 kg ha^?1 more cowpea, soybean and pigeon pea grain yields in Salima, Mzimba and Mangochi districts, respectively, compared with CA. Similarly, CA had 1100 and 950 kg ha^?1 more groundnut grain yields than CT in Salima and Mzimba districts in the second and third seasons, respectively. Over the three-year study period, partial land equivalent ratio for maize ranged from 0.78 to 1.24. Largest net returns were achieved by intercropping maize with pigeon pea in Mangochi and rotating maize and groundnut in Mzimba and Salima districts.     

Farmers' participation in the National Accelerated Food Production Project (NAFPP) in Nigeria

A limited dependent-variable model is employed to determine factors influencing farmers in making decisions about whether or not to participate in the National Accelerated Food Production Project Scheme (a voluntary scheme launched in Nigeria to make the country self-sufficient in food production) and the number of farm practices adopted from its technological package for those who do participate.

The empirical results of the study indicate that the probability of a farmer participating in the NAFPP Scheme and the number of farm practices adopted can be influenced by farm size, the farmer's age and his ability to read and write, his membership of a farmers' co-operative society, the frequency of his contact with extension agents and his ability to acquire credit. In addition, it is estimated that age and membership of a co-operative society have a greater effect on the probability that a farmer will participate in the scheme while other factors have a greater effect on the number of farm practices adopted for those who do participate.

As a consequence, land reform and mass literacy policies are recommended to enhance farmers' participation in the NAFPP Scheme. It is also suggested that policies that encourage farmers to form and participate actively in the activities of their local co-operative societies, liberalise credit facilities and increase the number of agricultural extension agents are likely to enhance farmers' active participation in the Scheme, which may result in increasing food production in the country.     

Effects of a salivary stimulant, slaframine, on ruminal fermentation, bacterial protein synthesis and digestion in frequently fed steers

Slaframine (SF), a parasympathomimetic salivary stimulant, was administered i.m. (10, 15 or 20 micrograms SF/kg BW) to ruminally and abomasally fistulated steers at 12-h intervals for 18-d periods in a latin square-designed experiment. Steers were fed semicontinuously (12 times daily) a 40:60 roughage:concentrate diet at twice their net energy requirement for maintenance. Ruminal digestion coefficients for DM, ADF and starch were 10 to 16% lower and linearly related in an inverse manner to the level of SF administered (P less than .05). Postruminal digestion of DM, ADF and starch increased as much as 46.7, 9.5 and 44.0%, respectively, in a fashion linearly related (P less than .05) to the level of SF administered. Total tract digestion of DM and ADF were not affected by SF; however, total tract starch digestion was increased as much as 5% and was related linearly (P less than .05) to SF treatment. With SF administration, as much as 13% more bacterial protein exited the rumen, resulting in a 16.5% linear improvement (P less than .1) in the efficiency of ruminal bacterial protein production per 100 g of OM fermented. Ruminal concentrations of VFA, ammonia and pH were not affected by SF. These results demonstrate a positive relationship between salivation and ruminal bacterial protein synthesis and suggest that feed utilization by ruminants may be improved by pharmacological stimulation of salivary secretions.     

Growth rate, diet digestibility, and serum proclactin of yearling horses fed non-infected and infected tall fescue hay

To determine to effect of feeding tall fescue hay infected with endophyte on growth rate, diet digestibility, and serum prolactin, 17 Quarter Horse yearlings were fed a diet of 60% concentrate and 40% tall fescue hay for 5 months. Diets were formulated to meet 1989 NRC recommendations for moderate growth. The dietary treatments included either non-infected (E-, n=9) or infected (E+, n=8) tall fescue hay. Field sampling determined a 52% infection rate of the E+ hay with the endophyte Acremonium coenophialum. Initially and at 29-day intervals, yearlings were weighed and measured for skeletal growth including: (1) height at the withers, (2) length of bone between knee and fetlock, (3) length of bone between hock and fetlock, and (4) the circumference of fore and rear cannon bones. Total fecal collection from the 10 geldings during the last month of the trial permitted the calculation of diet digestibility. Serum samples were taken throughout the trial to determine prolactin response to dietary treatments.The E+ fescue hay did not affect (P>.05) growth rate of yearling horses. Yearlings gained .40 and .38 kg/d when consuming the E− and E+ based diets, respectively. Geldings gained more (P<.05) than fillies. Changes in height at the wither and length and circumference of the fore and rear cannon were positive but did not differ between hay treatments or sexes.E+ fescue hay diets tended to be lower in dry matter, apparent energy, and crude protein digestibility, but values were not statistically different. Fiber digestibility was lower (P<.01) for the diet based on E+ hay. Neutral detergent fiber digestibility averaged 66.2 and 54.4% for E− and E+ diets, respectively.Acid detergent fiber digestibility averaged 78.9 and 64.5% for E− and E+ diets, respectively. Although fiber digestibility of E+ tall fescue hay was lower than E-hay, grain supplementation supportive of a moderate growth rate produced equal growth among yearling horses. Also, no differences in prolactin were apparent between the yearlings fed E− and E+ tall fescue hay.     

Mice inoculated with marek's disease tumor cells: Increased number of lymphomas

Germfree derived CFW_wd mice were inoculated with tumor cells from chickens with Marek's disease and observed for any long term effect. Nineteen per cent of these animals developed tumors whereas the incidence in control animals was 0.2%. Of those animals which developed tumors, 62% of the animals were observed to have ataxia before tumor development. Marek's disease herpesvirus was never observed in any of the murine tumors.