Efficient concepts for large erectable space structures

The status of Langley Research Center development of the nestable column concept is reviewed including results of member and truss component tests, and planned assembly studies. In addition, more recent studies of alternative member concepts are presented. Preliminary results on relative efficiency of several types of truss-type columns are compared and future test plans discussed

Sheep Production Guide

This publication provides various management practices to increase the productivity of the ewe flock. It discusses target dates, a timeline for early lambing, production records, lambing difficulties, and artificial rearing of lambs, as well as management of the flock, lambs, and wool

Addressing the shortcomings of traditional multiple-choice tests: subset selection without mark deductions

This article presents the results of an empirical study of “subset selection” tests, which are a generalisation of traditional multiple-choice tests in which test takers are able to express partial knowledge. Similar previous studies have mostly been supportive of subset selection, but the deduction of marks for incorrect responses has been a cause for concern. For the present study, a novel marking scheme based on Akeroyd’s “dual response system” was used instead. In Akeroyd’s system, which assumes that every question has four answer options, test takers are able to split their single 100% bet on one answer option into two 50% bets by selecting two options, or into four 25% bets by selecting no options. To achieve full subset selection, this idea was extended so that test takers could also split their 100% bet equally between three options. The results indicate increased test reliability (in the sense of measurement consistency), and also increased satisfaction on the part of the test takers. Furthermore, since the novel marking scheme does not in principle lead to either inflated or deflated marks, this makes it easy for educators who currently use traditional multiple-choice tests to switch to using subset selection tests

Vitamin A Bioptency as Measured by Stores of Vitamin A in Livers of Feedlot Cattle

The objective of these experiments was to evaluate the biological potency of two sources of vitamin A premix differing in freshness when administered to fattening beef cattle. Chemical assays were compared with blood and liver vitamin A content to measure the biopotency of the vitamin

Effects of Avoparcin on Performance of Feedlot Heifers

Avoparcin is a glycopeptide antibiotic produced by a strain of streptomyces candidus with activity against certain gram positive organisms. It has been reported to reduce the ratio of acetate to propionate produced during rumen fermentation and to improve weight gain and feed efficiency of feedlot cattle. This study was conducted to evaluate the effects of 30, 45 and 60 grams per ton of avoparcin and 30 grams per ton of monensin in the feed on weight gain, feed utilization and carcass quality of finishing heifers over a 140-day feeding period

Magnetic phase diagram of the frustrated S=1/2 chain magnet LiCu_2O_2

We present the results of the magnetization and dielectric constant measurements on untwinned single crystal samples of the frustrated S=1/2 chain cuprate LiCu_2O_2. Novel magnetic phase transitions were observed. A spin flop transition of the spiral spin plane was observed for the field orientations H||a,b. The second magnetic transition was observed at H~15 T for all three principal field directions. This high field magnetic phase is discussed as a collinear spin-modulated phase which is expected for an S=1/2 nearest-neighbor ferromagnetic and next-nearest-neighbor antiferromagnetic chain system

Randomized placebo controlled trials of n-acetyl cysteine as adjunct therapy for schizophrenia and bipolar disorder

Glutathione is the principal antioxidant of the brain. There is evidence of oxidative stress, lowered brain glutathione and genetic linkage involve glutathione metabolic genes in schizophrenia and bipolar disorder. N-acetyl cysteine (NAC) is a safe, orally bioavailable, precursor of glutathione. NAC has been shown to reverse animal models of oxidative stress, and raises brain glutathione levels.<br /

Effect of vitamin A Injections on Blood and Liver Levels in Cattle Fed Low-Carotene Diets

The objectives of these experiments were twofold, first, to study the effects of length of feeding period and dosage level of injected vitamin A on vitamin A status of steers fed a low carotene finishing rations without supplemental vitamin A, and, second, to study the effect of dosage level of injected vitamin A on liver storage of the vitamin following a period of feeding considered to have resulted in major depletion of prior body stores of the vitamin