Assessment of cable tensile forces in active winch-assist harvesting using an anchor machine configuration

European Journal of Forest Research - The growing interest in accessing steep terrain is pushing the expansion of the operating range of ground-based machines through winch-assist technology....     

Acanthocephalan infection and sparganosis in a green tree snake (Dendrelaphis punctulata)

Acanthocephalan and spargana parasites were identified within a body wall mass during exploratory surgery in a wild green tree snake. Acanthocephalan parasites have not previously been reported in this species. Surgical excision, the treatment of choice, could not be achieved because of the extensive infiltration of the coelomic cavity.     

The borders within: Mobility and enclosure in the Riau Islands1

Abstract: The border studies literature makes a strong case against claims for unfettered transnationalism and ‘borderlessness’ in our ‘globalising world’. However, its focus on movement across borders means that it fails to address bordering practices that occur within the nation‐state as a result of transnational activity. In this paper, we extend Cunningham and Heyman’s concepts ‘enclosure’ and ‘mobility’ to confront the different layers of bordering (both physical and non‐physical) that have occurred in Indonesia’s Riau Islands since they became part of the Indonesia–Malaysia–Singapore Growth Triangle.     

Terrestrial ecosystem processes of Victoria Land, Antarctica

Terrestrial environments of Victoria Land, Antarctica are ideal systems to test hypotheses about the sensitivity of ecosystem processes to climate variability, and the relationships between soil biodiversity and ecosystem functioning because of their high sensitivity to climate change and their limited diversity. This region is also considered among the most pristine of ecosystems, and therefore may serve as an indicator for detecting the response of other ecosystems to global environmental change. Rates and controls over key ecosystem processes remain poorly documented over much of Victoria Land, but it is generally held that the distribution and functioning of soil communities are most limited by the availability of liquid water and organic carbon. Here we review examples of ecosystem processes from several sites in North and South Victoria Land and develop a regional synthesis accounting for variation in the availability of soil resources (i.e. liquid water, organic matter, inorganic nutrients). Variation in soil microclimate, organic matter, moisture and salinity encountered over gradients of coastal to interior sites, latitude, and soil chronosequences are the primary controls over the structure of soil communities and their functioning. Imbalanced stoichiometric nutrient ratios frequently encountered in Victoria Land ecosystems also contribute to limited distribution of soil biota, and where they occur these elemental imbalances indicate lower biological activity and little biotic control over bulk element ratios in soils. Priorities and future directions of Victoria Land soil and ecosystem research are also discussed.     

Landscape evaluation of female black bear habitat effectiveness and capability in the North Cascades, Washington

We used logistic regression to derive scaled resource selection functions (RSFs) for female black bears at two study areas in the North Cascades Mountains. We tested the hypothesis that the influence of roads would result in potential habitat effectiveness (RSFs without the influence of roads) being greater than realized habitat effectiveness (RSFs with roads). Roads consistently had a negative influence on black bear RSFs across seasons and study areas. Roads reduced habitat effectiveness during all seasons at both study areas and changes in the potential habitat values ranged from 1.7% to 16.9%. The greatest reduction in habitat values occurred during the early-season on the west-side study area due to high open road densities. These results support the hypothesis that roads reduce habitat effectiveness for black bears. The influence of roads could be reduced through road closures to reduce open road densities and limit traffic volumes. We then used the scaled RSFs in a habitat-based population model to assess the influences of timber harvest and roads on potential black bear population sizes. On the west-side study area the potential black bear population size was most influenced by moderate use roads and timber harvest during the early-season (41% reduction). On the east-side study area, low use roads had the greatest effect on potential black bear population during the early-season (10% reduction). During the late-season, in both study areas, roads had less influence on the potential population sizes as bears were able to access habitats away from roads. The habitat-population model provided reasonable estimates of bear densities compared to other study areas with similar habitats and could be extrapolated to estimate potential black bear populations in other areas with similar habitats. This approach may provide a useful link between the landscape ecology and population biology of black bears, and could eventually be useful in the development of habitat-based population viability analyses.     

Alterations in carbon fixation during power plant entrainment of estuarine phytoplankton

Productivities of natural phytoplankton assemblages were significantly altered in passage through a cooling system of an electrical power station in mid-Chesapeake Bay, U.S.A. Carbon fixation in assemblages collected at the intake structure was significantly lower than rates noted at the discharge in June but significantly higher than rates observed at discharge in July through September. Productivity of a representative of the microflagellates, Cryptomonas acuta, was significantly reduced after passage through the plant (ΔT = 6 °C) in July through September. Photosynthetic C incorporation rates for the dinoflagellate Prorocentrum mariae-lebouriae, the centric diatom Cyclotella caspia and the pennate diatom Thalassionema nitzschioides were not altered during entrainment. These data support previous observations of lower fixation rates and cell lysis in microflagellates than in more rigid diatoms following power plant entrainment.     

Two G protein oncogenes in human endocrine tumors

Somatic mutations in a subset of growth hormone (GH)-secreting pituitary tumors convert the gene for the alpha polypeptide chain (alpha s) of Gs into a putative oncogene, termed gsp. These mutations, which activate alpha s by inhibiting its guanosine triphosphatase (GTPase) activity, are found in codons for either of two amino acids, each of which is completely conserved in all known G protein alpha chains. The likelihood that similar mutations would activate other G proteins prompted a survey of human tumors for mutations that replace either of these two amino acids in other G protein alpha chain genes. The first gene so far tested, which encodes the alpha chain of Gi2, showed mutations that replaced arginine-179 with either cysteine or histidine in 3 of 11 tumors of the adrenal cortex and 3 of 10 endocrine tumors of the ovary. The mutant alpha i2 gene is a putative oncogene, referred to as gip2. In addition, gsp mutations were found in 18 of 42 GH-secreting pituitary tumors and in an autonomously functioning thyroid adenoma. These findings suggest that human tumors may harbor oncogenic mutations in various G protein alpha chain genes.     

Probing the Local Effects of Magnetic Impurities on Superconductivity

The local effects of isolated magnetic adatoms on the electronic properties of the surface of a superconductor were studied with a low-temperature scanning tunneling microscope. Tunneling spectra obtained near magnetic adsorbates reveal the presence of excitations within the superconductor's energy gap that can be detected over a few atomic diameters around the impurity at the surface. These excitations are locally asymmetric with respect to tunneling of electrons and holes. A model calculation based on the Bogoliubov-de Gennes equations can be used to understand the details of the local tunneling spectra.     

Spontaneous formation of macroscopic chiral domains in a fluid smectic phase of achiral molecules

A smectic liquid-crystal phase made from achiral molecules with bent cores was found to have fluid layers that exhibit two spontaneous symmetry-breaking instabilities: polar molecular orientational ordering about the layer normal and molecular tilt. These instabilities combine to form a chiral layer structure with a handedness that depends on the sign of the tilt. The bulk states are either antiferroelectric-racemic, with the layer polar direction and handedness alternating in sign from layer to layer, or antiferroelectric-chiral, which is of uniform layer handedness. Both states exhibit an electric field-induced transition from antiferroelectric to ferroelectric.