Peak Time Period Research Articles

Weakness in the Newborn Calf

The peak time period for the average beef producer to experience the majority of calf losses has consistently been from the time of birth through the first seven days of life. Weakness is a principal clinical sign of diseases or conditions responsible for mortality including birth trauma, prematurity or dysmaturity, congenital malformations, metabolic defects, intrauterine infection, anoxia or hypoxia, hypothermia, starvation, extremes in birth weight, and post-natal infection. This article discusses anoxia/hypoxia and septicemia in greater detail because of their involvement as a common cause of weakness in the newborn calf.

Immature Developmental Requirements and Factors Influencing Spring Emergence of Argyrotaenia citrana (Lepidoptera: Tortricidae) on Caneberries∼ Rubus spp., in the Pacific Northwest

Rate of development for larvae and pupae of orange tortrix, Argyrotaenia citrana (Fernald), reared on artificial diet medium under field conditions varied significantly between winter/spring and summer experiments. Mean developmental requirements for male and female larvae and pupae were 481, 531, 178, and 168 degree-days (DD50°C), respectively. In laboratory experiments, nitrogen content of various food sources significantly influenced survivorship and developmental rates of larvae. Estimated emergence of adults from several field sites in Oregon and Washington in 1983, 1984, and 1985 occurred 300–700 DD from 1 January. The 50% cumulative emergence ranged from 470 to 500 DD for males and from 520 to 560 DD for females. Cumulative emergence of an overwintering population heavily parasitized by the braconid Apanteles aristoteliae Viereck, was accelerated ca. 75 DD in 1983. Two peaks in weekly catch in pheromone traps occurred in caneberry fields with overwintering populations. The first coincided with peak male emergence; the second occurred after 750 DD and varied in magnitude relative to the first peak. In fields not harboring an overwintering population, catch reached a maximum during the second peak-time period, suggesting that immigration of males into these sites was influencing catch.

A microprocessor-based noninvasive arterial pulse wave analyzer.

A microprocessor-based noninvasive arterial pulse wave analyzer is described which detects the peripheral, arterial pulse of an individual and extracts from the pulse waveform clinically important features. Continuous-wave Doppler microwaves (24.125 GHz) are employed to measure the arterial wall movements associated with the pressure pulse wave. Through the use of feature extraction techniques, key landmarks are located on the pulse contour. Then the pulse rate, the foot-to-systolic peak time period, and the foot-to-dicrotic notch time period are calculated. Preliminary results are presented which indicate that the arterial pulse wave analyzer can accurately determine the movement of the arterial wall and is able to analyze the pulse wave contour for clinically important features.

Applying Mathematical Programming to Measure Electricity Marginal Costs

Marginal costs defined as the additional costs needed for meeting additional electricity demand are estimated by using separable programming model analysis. The shadow prices obtained with a linear programming optimal solution are transformed into marginal costs corresponding to the spontaneous peak, peak, middle, and off-peak time periods in the load duration curve. Marginal cost corresponding to the spontaneous peak time period, which is interpreted as the capital cost increase minus the fuel cost saving, is represented as the sum of those two costs by using the inverse of the optimal basis matrix of the linear programming model.