The Use of Confined Colonies of Wild Mice (Mus musculus L.) in the Evaluation of Rodenticides1

Experimental studies have been conducted using penned families of wild house mice (Mus musculus L.) treated with different rodenticides and subjected to various poisoning regimes. The results showed that such investigations on rodents can provide valuable post-laboratory information on the relative merits and the best mode of application of rodenticides prior to their examination under field conditions. Pen population studies also permit closer study of feeding activity, bait acceptance, social behaviour and other factors that can affect rodenticidal efficacy.     

Effects of night-time humidity and nutrient solution concentration on the calcium content of tomato fruit

Calcium intake into tomato fruits was greater when nights were humid rather than dry and nutrient solutions dilute rather than concentrated.The concentration of calcium in the wall tissue of the distal segment of fruits damaged by blossom-end rot was 0.03% of dry matter, but was 2- to 3-fold greater in the most favourable conditions of humidity and solution concentration, when fruits were undamaged.Adding extra calcium to the nutrient solution increased the calcium concentration in the proximal, but not in the middle or distal, segments of the fruit.The results support the hypothesis that a positive root pressure at night promotes transport of calcium into tissues and organs that have restricted transpiration.     

Plant Species Composition and Forage Production 14 Yr After Biosolids Application and Grazing Exclusion

This paper examines the effects of a single surface application of biosolids (at 20 dry Mg ha^{? 1}) on plant species composition, forage quality and quantity, and C stocks after 14 yr of rest in rangelands of the Central Interior of British Columbia. More than two times the aboveground biomass of grasses and the percent cover of plant litter were found in the biosolids treatment relative to the control, along with reductions in bare soil and microbiotic crust cover. Significantly greater plant uptake of all macronutrients (C, N, P, K, S, Ca, and Mg); most micronutrients (B, Cu, Mn, Mo, and Zn); and Al occurred in the biosolids treatment. P and Cu were the only two nutrients to be more concentrated in the biosolids-treated forage relative to the control forage, while N, Mg, and protein were more concentrated in the control forage. No significant difference in forage digestibility was found between biosolids and control treatments. Bluebunch wheatgrass, the late-seral native grass species, had significantly increased cover and aboveground biomass in the biosolids treatment relative to the control; however, between 2006 and 2016, non-native Kentucky bluegrass had reached > 25% cover in the biosolids plots, perhaps restricting the full recovery of bluebunch wheatgrass. Our findings indicate that biosolids application to ungrazed rangeland can increase long-term forage production and reduce bare soil. However, at our study site biosolids application also led to a long-term shift in the plant community composition away from the late-seral (i.e., bluebunch wheatgrass) trajectory, and the effects of this shift on rangeland health and productivity require further investigation.     

The effect of intensity of nutrient supply on growth,yield and leaf composition of black currant grown in sand culture

Black currants were grown from cuttings in sand culture to study the effect of intensity of nutrient supply on growth, yield and leaf composition of the plants. An increase in frequency of nutrient supply gave an increase in the amount of fruiting wood produced in 1966 and in the yield of fruit in 1967. Leaf phosphorus concentrations ranged from 0·48-1·61% as the intensity of nutrient supply increased; fractionation of phosphorus in leaf samples showed that the largest part of this variation was accounted for by differences in the inorganic phosphate content of the leaf. Leaf concentrations of N, K, Ca, Mg, Fe, Cu, Mn and Zn were little affected by the experimental treatments.     

Allantoic fluid electrolytes and urate of embryonic Japanese quail subject to differential water loss

1. The composition of allantoic fluid from Japanese quail was measured from days 9 to 14 of incubation.

2. The effect of the inhibitor of urate synthesis, allopurinol, upon weight, electrolytes and urate of allantoic fluid was investigated in eggs subject to different rates of water loss. The composition of plasma and the solid fraction of allantoic fluid was also investigated.

3. During the second half of incubation allantoic fluid water weight decreased, as did pH, and sodium, chloride and bicarbonate concentrations. Fluid urate and potassium concentrations increased, but osmolality was unchanged.

4. Allantoic urate and electrolyte concentrations were greatest, and fluid weight lowest, in eggs subject to high water loss.

5. Allopurinol reduced the total urate of allantoic fluid, and increased osmolality and electrolyte concentrations. Allopurinol had no effect on plasma osmolality.

6. It is concluded that in eggs of high water loss allantoic fluid osmolality was reduced by sequestration of sodium by urate in the fluid solid fraction. In eggs subject to low water loss fluid osmolality was reduced by the replacement of chloride by colloidal urate.     

Morphological changes in human scalp hair roots during deprivation of protein

Human subjects were deprived of protein for 15 days, after which time hair from the scalp of each subject was plucked and examined. Both the bulb and the external root sheath showed morphological changes. This technique may therefore be useful in diagnosing proteincalorie malnutrition.     

Bryophyte responses to fragmentation in temperate coastal rainforests: A functional group approach

The species richness and frequency of occurrence of bryophytes within taxonomic and functional groups was examined in relation to the size of 20 old-growth patches (size range: 0.6-63.6 ha) remaining after logging in temperate rainforests of coastal British Columbia. At the centre of each remnant patch, bryophytes were sampled in sixty-three 10 cm × 30 cm microplots on three substrate-types (forest floor, downed logs and tree bases). Generalized linear models demonstrated that the species richness and frequencies of some bryophyte functional groups were related to patch size. In particular, some dispersal-limited groups (perennial stayers) and microclimate-sensitive groups (closed canopy species, epixylic (log-dwelling) species, and liverworts) showed significant declines in either richness or frequency as patch size decreased. In contrast, colonists and open canopy species showed little association with patch size. Many, but not all, of the significant patch size relationships disappeared when the three smallest patches (0.6-1.8 ha) were eliminated from the analysis. These results suggest that patches sized 3.5 ha or larger may provide habitat capable of sustaining a diverse array of bryophyte functional groups in temperate rainforest landscapes.     

奶酪产品(奇饲粉)的营养价值及其在动物饲料中的应用

奶酪是一种浓缩的牛奶制品,由新鲜的或成熟固态或半固态形式的乳蛋白（包括酪蛋白和一些白蛋白）、乳脂肪和乳矿物质组成,包含了牛奶中的大部分蛋白质、脂肪和主要的矿物质如钙和磷.奶酪不仅具有良好的适口性,同时由于其营养成份浓度高且组成合理,易于消化吸收,因此也是动物生产中重要的营养物质源.在1994年,奶酪提供了美国食物供应中可利用蛋白质的8%,钙的23%和核黄素的5%,以及许多其它养分,只有少量的奶酪被用于动物饲料中.某些厂家将奶酪进行加工而用作饲料.由于成本相对较高,这些产品仅用于优质的饲料,如乳猪开食料、宠物饲料和水产饲料.