Range vegetation type mapping and above-ground green biomass estimations using multispectral imagery

The author has identified the following significant results. Range vegetation types have been successfully mapped on a portion of the 68,000 acre study site located west of Baggs, Wyoming, using ERTS-1 imagery. These types have been ascertained from field transects over a five year period. Comparable studies will be made with EREP imagery. Above-ground biomass estimation studies are being conducted utilizing double sampling techniques on two similar study sites. Information obtained will be correlated with percent relative reflectance measurements obtained on the ground which will be related to image brightness levels. This will provide an estimate of above-ground green biomass with multispectral imagery

A novel, resistance-linked ovine PrP variant and its equivalent mouse variant modulate the in vitro cell-free conversion of rPrP to PrPres

Prion diseases are associated with the conversion of the normal cellular prion protein, PrPc, to the abnormal, disease-associated form, PrPSc. This conversion can be mimicked in vitro by using a cell-free conversion assay. It has recently been shown that this assay can be modified to use bacterial recombinant PrP as substrate and mimic the in vivo transmission characteristics of rodent scrapie. Here, it is demonstrated that the assay replicates the ovine polymorphism barriers of scrapie transmission. In addition, the recently identified ovine PrP variant ARL168Q, which is associated with resistance of sheep to experimental BSE, modulates the cell-free conversion of ovine recombinant PrP to PrPres by three different types of PrPSc, reducing conversion efficiencies to levels similar to those of the ovine resistance-associated ARR variant. Also, the equivalent variant in mice (L164) is resistant to conversion by 87V scrapie. Together, these results suggest a significant role for this position and/or amino acid in conversion

Expression patterns of chondrocyte genes cloned by differential display in tibial dyschondroplasia

AbstractTibial dyschondroplasia (TD) appears to involve a failure of the growth plate chondrocytes within growing long bones to differentiate fully to the hypertrophic stage, resulting in a mass of prehypertrophic chondrocytes which form the avascular TD lesion. Many biochemical and molecular markers of chondrocyte hypertrophy are absent from the lesion, or show reduced expression, but the cause of the disorder remains to be identified. As differentiation to the hypertrophic state is impaired in TD, we hypothesised that chondrocyte genes that are differentially expressed in the growth plate should show altered expression in TD. Using differential display, four genes, B-cadherin, EF2, HT7 and Ex-FABP were cloned from chondrocytes stimulated to differentiate to the hypertrophic stage in vitro, and their differential expression confirmed in vivo. Using semi-quantitative RT-PCR, the expression patterns of these genes were compared in chondrocytes from normal and TD growth plates. Surprisingly, none of these genes showed the pattern of expression that might be expected in TD lesion chondrocytes, and two of them, B-cadherin and Ex-FABP, were upregulated in the lesion. This indicates that the TD phenotype does not merely reflect the absence of hypertrophic marker genes, but may be influenced by more complex developmental mechanisms/defects than previously thought

Emergent behavior of soil fungal dynamics:influence of soil architecture and water distribution

Macroscopic measurements and observations in two-dimensional soil-thin sections indicate that fungal hyphae invade preferentially the larger, air-filled pores in soils. This suggests that the architecture of soils and the microscale distribution of water are likely to influence significantly the dynamics of fungal growth. Unfortunately, techniques are lacking at present to verify this hypothesis experimentally, and as a result, factors that control fungal growth in soils remain poorly understood. Nevertheless, to design appropriate experiments later on, it is useful to indirectly obtain estimates of the effects involved. Such estimates can be obtained via simulation, based on detailed micron-scale X-ray computed tomography information about the soil pore geometry. In this context, this article reports on a series of simulations resulting from the combination of an individual-based fungal growth model, describing in detail the physiological processes involved in fungal growth, and of a Lattice Boltzmann model used to predict the distribution of air-liquid interfaces in soils. Three soil samples with contrasting properties were used as test cases. Several quantitative parameters, including Minkowski functionals, were used to characterize the geometry of pores, air-water interfaces, and fungal hyphae. Simulation results show that the water distribution in the soils is affected more by the pore size distribution than by the porosity of the soils. The presence of water decreased the colonization efficiency of the fungi, as evinced by a decline in the magnitude of all fungal biomass functional measures, in all three samples. The architecture of the soils and water distribution had an effect on the general morphology of the hyphal network, with a "looped" configuration in one soil, due to growing around water droplets. These morphologic differences are satisfactorily discriminated by the Minkowski functionals, applied to the fungal biomass

John Richardson (1787-1865)

Sir John Richarson first achieved fame as a surgeon and naturalist with the two arctic land expeditions led by John Franklin in 1819-22 and 1825-27. A true generalist, Richardson was competent in geology, mammalogy, ichthyology - a soon became knowledgeable in ornithology. He wrote three of the four volumes of Fauna Boreali-Americana, and edited zoological appendices for the voyages of Parry, Ross, Back, Beechey, Kellett, and Belcher. A formidable ichthyologist who described 43 still-accepted genera and over 200 new species of fish, he was also a key member of the Strickland Committee, which set the rules of zoological nomenclature. ... His name is perpetuated by numerous plants, fish, birds, and mammals (including Richardson's ground squirrel), and by such geographical features as the Richardson Mountains and Richardson River. ..

Pierre St. Germain (1790-1843?)

Of the fifteen hired men on John Franklin's first land expedition, Pierre St. Germain has been the most underrated. Although a rogue, a rebel, and a troublemaker, he was the strongest, most resourceful, and most versatile man on the expedition. ... St. Germain, part French and part Indian, served in the Athabasca district for the North West Company from 1812 to 1818. In 1819 he joined the Hudson's Bay Company at a wage of 2,000 Montreal livres (100 Pounds Sterling) per annum and served as an interpreter at Fort Resolution, Great Slave Lake. ... On 5 June 1820, Colin Robertson wrote McVicar, giving permission for St. Germain to join the arctic land expedition under the command of Lt. John Franklin. On 25 July 1820, St. Germain entered into an agreement with Franklin for wages of "3000 Livres per annum until his return to Ft. Wedderburn." This 150 Pounds Sterling was two-and-a-half times the amount Franklin offered a French Canadian voyageur. St. Germain's employers recognized his ability but also his independent ways. Robertson described St. Germain as "an intelligent young man" and 5 June 1820 wrote "I have given up an excellent Chippeyan interpreter, St. Germain." McVicar considered him indispensable, mentioning how he could travel without either a blanket or provisions, but also noting his liking for alcohol. ... Richardson considered St. Germain to be one of the most reliable men on the expedition and the one with the most influence on the accompanying Copper Indians. St. Germain was intelligent, determined, and when reasonably fed, indefatigable. He made the preliminary trip to Point Lake with Back and Hood, 29 August-10 September 1820. During the winter of 1820-21, he snowshoed 440 km from Fort Enterprise to Fort Resolution, bringing back the two Eskimos, Augustus and Junius. Strong, resourceful, practical, a man of great stamina, St. Germain was also exceedingly dexterous, evidenced by his use of a made-down canoe to cross the Burnside River on 9 September and, five days later, to ferry Franklin across Belanger Rapids. St. Germain alone had the ability to improvise that allowed him single-handedly to convert the fragments of "painted canvas" or "oil-cloth" into a cockleshell that would finally transport everyone across Obstruction Rapids on 4 October, after nine days of crucial delay. ... As a troublemaker, St. Germain gained the enmity of both Franklin and Back. As early as 23 March 1821, St. Germain expressed his concern about the dangers involved in the proposed arctic explorations and shared his views with Akaitcho's Copper Indians. Because of this indiscretion, Franklin that day described him as "an artful man" and said he was "perfectly satisfied of his baseness." ... By September 1822-The Franklin expedition over-HBC Chief Trader Alexander Roderick McLeod engaged St. Germain at Lake Athabasca to serve in the capacity of interpreter. ... He continued to serve the Company as interpreter in the Mackenzie River District until 12 September 1834. St. Germain then retired to the Red River Settlement, where he purchased 50 acres of land on 13 April 1835. ... Although too independent to fit easily into naval discipline, Pierre St. Germain was an indispensable man. Without his hunting and craft skills, Franklin, Richardson, Back, and Hepburn would have perished. Without him, Franklin's first arctic land expedition, like the 1845 disaster, would have had no surviving officers and no published accounts. It was a close call indeed