Brook trout occupancy in rivers and streams of the Mixedwood Plains Ecozone,Ontario

Brook trout (Salvelinus fontinalis) are an iconic freshwater salmonid native to northeastern North America. They prefer cold, clean rivers and lakes, and have been culturally, socially and economically valued for decades. Overharvest and deforestation associated with European settlement in southern Ontario, Canada led to notable declines in brook trout abundance in rivers and streams by the late 1800s. Today, they are threatened by further habitat degradation, non-native species, and climate change. In this study, we document brook trout occupancy in rivers and streams of the Mixedwood Plains Ecozone in southern Ontario, between 1970–1980 and 2000–2010. We used generalised linear models to determine occupancy variation between the two time periods at five spatial scales spanning multiple watershed levels. We detected a decline in occupancy between time periods for the tertiary (from 23% to 17%) and quaternary (from 35% to 22%) watershed scales. In the Credit River-Sixteen Mile Creek watershed, mean occupancy decreased to a third of past estimate (from 31% to 10%). For a subset of 86 sites with overlapping sampling in both periods no temporal trend was detected, but a post-hoc analysis indicated low statistical power (0.07), which suggested that more intensive sampling would be needed to better quantify brook trout occupancy changes at this scale. The occupancies quantified for the past period in our study may serve as benchmarks for brook trout restoration efforts.     

It may be a dog's life but the relationship with her owners is also key to her health and well being: communication in veterinary medicine.

Effective communication is necessary for achieving important outcomes in veterinary practice, including patient health, accuracy, efficiency, and economic viability. Communication is a series of learned skills. Daily practice, feedback, and refinement are the ingredients for continued practice success.     

The effect of anesthetic drug choice on accuracy of high-definition oscillometry in laterally recumbent horses

Objective

To determine the accuracy of high-definition oscillometry (HDO) for arterial pressure measurement during injectable or inhalation anesthesia in horses.

Spatial dependency of soil nutrient availability and microbial properties in a mixed forest of Tsuga heterophylla and Pseudotsuga menziesii, in coastal British Columbia, Canada

Spatial variations in nutrient concentrations and turnover may contribute to variations in productivity within forest ecosystems and be responsible for creating and maintaining diversity of plant species. The aim of this study was to relate spatial patterns in soil nutrient availability and microbial properties in the forest floor and mineral soil in order to explore the controls on variations in nutrient availability in the two horizons. Microbial C, N and P, extractable N and P, and plant-available nutrients as estimated by plant root simulator probes were measured. We then used geostatistical techniques to determine the scale of spatial autocorrelation in the forest floor and mineral soil. Several of the measured variables were spatially autocorrelated at a scale of tens to hundreds of meters. Although more variables were autocorrelated in the mineral soil than in the forest floor, spatial patterns in gravimetric moisture content and nutrient concentrations in the two horizons generally overlapped. The spatial patterns were probably caused by differences in topography, except for ammonium whose shorter range of spatial autocorrelation may reflect variations in nitrogen content of the canopy.     

Cloning and accumulation of anthocyanin biosynthesis genes in developing tubers

Anthocyanins are a class of flavonoids that are responsible for the pigmentation of red potato periderm. The cDNAs of two genes were cloned from ‘Norland’ periderm and, based on their sequence similarity to genes in various databases, were identified as the anthocyanin biosynthetic genes for leucoanthocyanidin dioxygenase (EC 1.14.11.19) and UDP glucose: flavonoid 3-O-glucosyl transferase (EC 2.4.1.91). The mRNA accumulation of these genes in periderm during the development of tubers was determined using RNA gel blot analyses. The mRNA of the putativeLDOX was detected in cortex tissue and microtubers, but not in periderm. While mRNA of the putativeUFGT was detected in cortex tissue and periderm of young tubers, but not in periderm of tubers weighing more than 25 g. These data suggest that accumulation ofLDOX andUFGT mRNA may limit anthocyanin synthesis as Norland tubers develop.     

克隆成年动物-什么是克隆动物的遗传年龄?

前言自从第一例成年体细胞克隆绵羊多利诞生以来(Wilmut,1997),牛(Kato,1998; Galli,1999;Renard,1999;Shiga,1999;Wells,1997;Zakhartchenko,1999;Hill,2000; Kubota,2000; Tian,2000)、小鼠(Wakayama,1998; 1999; Rideout,2000)、猪(Polejaeva,2000; Onishi,2000)、山羊(Keefer,2000)等多种成年动物的克隆后代相继问世.成年动物体细胞克隆技术在农业、医学、濒危动物保护以及基础研究等方面具有重大应用潜力.该项技术在应用于上述领域之前,对那些与克隆动物发育有关的潜在问题,有必要进行一番认真的研究.