Athabasca Valles, Mars: a lava-draped channel system

Athabasca Valles is a young outflow channel system on Mars that may have been carved by catastrophic water floods. However, images acquired by the High-Resolution Imaging Science Experiment camera onboard the Mars Reconnaissance Orbiter spacecraft reveal that Athabasca Valles is now entirely draped by a thin layer of solidified lava-the remnant of a once-swollen river of molten rock. The lava erupted from a fissure, inundated the channels, and drained downstream in geologically recent times. Purported ice features in Athabasca Valles and its distal basin, Cerberus Palus, are actually composed of this lava. Similar volcanic processes may have operated in other ostensibly fluvial channels, which could explain in part why the landers sent to investigate sites of ancient flooding on Mars have predominantly found lava at the surface instead.     

Some neurons of the rat central nervous system contain aromatic-L-amino-acid decarboxylase but not monoamines

Neurons containing the enzyme aromatic-L-amino-acid decarboxylase (AADC) but lacking either tyrosine hydroxylase or serotonin were found in the spinal cord of neonatal and adult rats by light and electron microscopic immunocytochemistry. The majority of these neurons localized to area X of Rexed contact ependyma. Thus, spinal AADC neurons have the enzymatic capacity to catalyze directly the conversion of the amino acids tyrosine, tryptophan, or phenylalanine to their respective amines tyramine, tryptamine, or phenylethylamine. These amines normally present in the central nervous system may be of potential clinical significance as endogenous psychotomimetics.     

Sensor‐based assessment of herbicide effects

Non‐destructive assessment of herbicide effects may be able to support integrated weed management. To test whether effects of herbicides on canopy variables could be detected by sensors, two crops were used as models and treated with herbicides at BBCH 20 using a logarithmic sprayer. Twelve days after spraying at BBCH 25 and 42 days after sowing, nine sensor systems scanned a spring barley and an oilseed rape field experiment sown at different densities and sprayed with increasing field rates of glyphosate and tribenuron‐methyl. The objective was to compare ED₅₀s for crops and weeds derived by the different sensors in relation to crop density and herbicides. Although sensors were not directly developed to detect herbicide symptoms, they all detected changes in canopy colours or height and crop density. Generally ED₅₀s showed the same pattern in response to crop density within herbicide, but there were marked differences between barley and oilseed rape. We suggest that the results of comparing the various sensor outputs could become a stepping stone to future standardisation for the benefit of the research and development of sensors that will detect herbicide effect on crops and weeds, particularly at the most vulnerable stages of development of the canopy.     

Animal and Vegetation Response to Modified Intensive–Early Stocking on Shortgrass Rangeland

A comparison of animal gains and vegetation trends was made from 2002–2008 between a continuous season-long stocking (SLS) system and a modified intensive–early stocking system (IES) with late-season grazing (IES 1.6× + 1; 1.6 times the number of animals of the SLS system from May 1 to July 15, and 1 times the number of animals of SLS from July 15 to October 1) on shortgrass native rangeland of western Kansas. The continuous season-long stocked system placed animals at a density of 1.37 ha · steer^?1 from May through October, or 2.63 animal unit months (AUM) · ha^?1, whereas the intensive–early stocked system with late-season grazing (3.33 AUM · ha^?1) stocked pastures at 0.85 ha · steer^?1 from May through the middle of July, and then stocked pastures at 1.37 ha · steer^?1 for the remainder of the grazing season by removing the heaviest animals mid-July each yr. Average daily gains (0.78 vs. 0.70 kg · d^?1, P = 0.039) and total animal gain (58 vs. 52 kg, P = 0.042) were different between the continuous season-long stocked and the intensive–early stocked animals during the first half of the grazing season. No difference was found between average daily gain (0.61 vs. 0.62 kg · d^?1, P = 0.726) and total animal gain (48 vs. 49 kg, P = 0.711) for the continuous season-long stocked and intensive–early stocked with late-season grazing animals during the last half of the season. Total individual animal gain (106 vs. 101 kg, P = 0.154) and average daily gain (0.70 vs. 0.66 kg · d^?1, P = 0.152) was not different between the continuous season-long stocked and the intensive–early stocked system animals that were on pasture the entire grazing season. Total beef gain on a land-area basis (96 vs. 77 kg · ha^?1, P = 0.008) was greater for the modified intensive–early stocked system with late-season grazing with greater animal densities. Changes in residual biomass and most key vegetation components at the end of the grazing season were not different between the two systems.     

Effect of orally administered epidermal growth factor on the jejunal mucosa of weaned pigs

The effect of ingested epidermal growth factor (EGF) on the small intestinal mucosa of conventionally weaned pigs was determined. At 21 days of age, 39 pigs were randomly distributed into suckling and weaned treatment groups that were administered 124 micrograms of EGF, 372 micrograms of EGF, or the dosing compound daily. Fecal water content was determined daily. On postweaning days 0, 3, 6, and 9, representative pigs from each group were euthanatized, and jejunal mucosa samples were collected for determination of villus-to-crypt ratio, total protein content, disaccharidase activities, and microbiological populations. At postweaning day 3, the 372-micrograms dose of EGF significantly (P less than or equal to 0.05) increased jejunal lactase and sucrase activities in the weaned pigs. Increased lactase activity was not greater than that of the suckling pig controls, whereas sucrase activity was significantly (P less than or equal to 0.05) higher than that of the suckling pig controls. Significant changes were not observed in villus-to-crypt ratio, mucosal protein content, or disaccharidase activities on other collection days.     

Growth-stimulating substances in porcine milk

Colostral and milk samples were collected from 6 primiparous sows on postpartum days 0, 9, 18, and 27. Insulin content was measured and epidermal growth factor (EGF) concentration was determined by use of radioimmunoassay and radioreceptor assay, respectively. Total milk protein concentration was measured colorimetrically. Concentrations of insulin, EGF, and protein in the colostral samples were significantly (P less than 0.01) higher than those found in the milk. Milk samples obtained from postpartum days 9, 18, and 27 did not differ significantly in insulin, EGF, or total protein content.     

Stratification, blinding and placebo effect in a randomized, double blind placebo-controlled clinical trial of gold bead implantation in dogs with hip dysplasia

The purpose of this study was to investigate the need for and choice of stratification factors, and the effects of blinding and placebo in a clinical experiment. Eighty dogs with canine hip dysplasia (CHD) were included in a randomized, placebo-controlled and double blind clinical trial with stratified parallel group design, in which body weight and degree of CHD were used as stratification factors. Thirty-eight dogs were allocated to gold bead implantation and 42 to placebo. After six months, 33 of the 42 placebo-treated dogs received gold bead implantation in an open study lasting a further 18 months. The main outcome variable in the study was change in pain signs of CHD as assessed by the owner. No significant difference in the main outcome variable, regardless of the treatment given, could be detected in the two chosen stratification factors. The only factor to influence the main outcome variable significantly was age. The blinding procedure used in the study, in which 60% of the owners correctly guessed the treatment given, was found sufficient. Of those who guessed the treatment erroneously, 88% believed the treatment given was gold bead implantation. The treatment efficacy after six months in the blinded treatment group was found to be significantly larger compared to the efficacy obtained in the open study. A significant placebo effect was therefore detected. CONCLUSION AND CLINICAL RELEVANCE: The age of the dogs influenced the outcome of the CHD treatment, and is recommended as a stratification factor. A significant placebo effect has to be expected and an optimal blinding procedure is necessary in similar clinical studies.