Efficiently locating conservation boundaries: Searching for the Tasmanian devil facial tumour disease front

Conservation management actions and decisions are often defined by the location of ecological boundaries, for example, the present range of invasive or threatened species. The position of these boundaries can be cryptic, and managers must therefore directly sample sites, an expensive and time-consuming process. While accurate boundary location techniques have been considered by ecological theorists, the issue of cost-effective, or optimal boundary location has not. We propose a general framework for boundary location which incorporates both cost-efficiency and uncertainty. To illustrate its application, we use it to help locate an infectious disease front in the endangered Tasmanian devil population. The method ensures optimal spatial sampling by maximizing the expected information gained from each sample. When resources are limited, our method provides more accurate estimates of the boundary location than traditional sampling protocols. Using a formal decision theory sampling design encourages economically efficient actions, and provides defensible and transparent rationale for management actions.     

The structure of a complex of recombinant hirudin and human alpha-thrombin

The crystallographic structure of a recombinant hirudin-thrombin complex has been solved at 2.3 angstrom (A) resolution. Hirudin consists of an NH2-terminal globular domain and a long (39 A) COOH-terminal extended domain. Residues Ile1 to Tyr3 of hirudin form a parallel beta-strand with Ser214 to Glu217 of thrombin with the nitrogen atom of Ile1 making a hydrogen bond with Ser195 O gamma atom of the catalytic site, but the specificity pocket of thrombin is not involved in the interaction. The COOH-terminal segment makes numerous electrostatic interactions with an anion-binding exosite of thrombin, whereas the last five residues are in a helical loop that forms many hydrophobic contacts. In all, 27 of the 65 residues of hirudin have contacts less than 4.0 A with thrombin (10 ion pairs and 23 hydrogen bonds). Such abundant interactions may account for the high affinity and specificity of hirudin.     

Type of kindergarten and other potential determinants of overweight in pre-school children

OBJECTIVE: The study aimed to assess the relationship of various types of kindergarten differing in length of care and food availability with the development of overweight in pre-school children. DESIGN, SETTING AND SUBJECTS: A cross-sectional study was carried out in 2002 in Stuttgart, Germany, as part of the school entrance examination. Height and weight of 2140 children (participation 70.2%) were measured and information on type of kindergarten and other potential determinants of overweight was collected by a parental questionnaire. Change in relative body mass index (BMI) position between the ages of 4 and 6 years was assessed using medical records. RESULTS: The prevalence of overweight or change in relative BMI position did not differ according to the type of kindergarten. For the prevalence of overweight in German children, adjusted odds ratios (OR) comparing institutions that open only in the morning with those opening in the morning and afternoon or for the full day were 0.86 (95% confidence interval (CI) 0.40, 1.83) and 0.63 (95% CI 0.25, 1.58), respectively. Parental BMI and duration of television watching were positively associated, and maternal educational status and duration of breast-feeding were negatively associated, with overweight and/or change in relative BMI position. The prevalence of overweight was substantially higher among non-German than among German children (adjusted OR 2.17 (95% CI 1.53, 3.07)). CONCLUSIONS: These data show no association between different types of kindergarten and the development of overweight in early childhood. Duration of television watching and breast-feeding, as well as the relatively high prevalence of overweight in ethnic minorities, deserve further attention.     

Chronic hepatitis in Doberman pinschers. A review

Summary

Chronic hepatitis in Doberman pinschers is predominantly seen in female dogs, usually between 4 and 7 years of age and was first recognized in the early eighties. The histopathological characteristics of Doberman hepatitis are those of micronodular cirrhosis with histological features of fibrosis, piece meal necrosis and progressive lymphocyte and plasma cell infiltration of the portal triads. Currently there are two hypotheses on the pathogenesis although neither of them has been elucidated. The first hypothesis is that of a copper toxicosis. The second is that of autoimmunity. Similarities and differences with other breeds and studies on both hypotheses are reviewed, as well as results of recent research of our group. Based on recent findings chronic hepatitis in Doberman pinschers is most likely to be a form of copper toxicosis. Although there are several indications that suggest autoimmunity as well, this still remains unclear.     

Gold nanoelectrodes of varied size: transition to molecule-like charging

A transition from metal-like double-layer capacitive charging to redox-like charging was observed in electrochemical ensemble Coulomb staircase experiments on solutions of gold nanoparticles of varied core size. The monodisperse gold nanoparticles are stabilized by short-chain alkanethiolate monolayers and have 8 to 38 kilodaltons core mass (1.1 to 1.9 nanometers in diameter). Larger cores display Coulomb staircase responses consistent with double-layer charging of metal-electrolyte interfaces, whereas smaller core nanoparticles exhibit redox chemical character, including a large central gap. The change in behavior is consistent with new near-infrared spectroscopic data showing an emerging gap between the highest occupied and lowest unoccupied orbitals of 0.4 to 0.9 electron volt.     

Further identification of Hippeastrum Mosaic Virus

Infectious virus was isolated fromHippeastrum plants by density gradient centrifugation and examined with the electron microscope. The average lengths of the flexuous particles were 643±24 nm.Samenvatting Infectieus virus kon worden geïsoleerd uitHippeastrum-planten die mozaïekverschijnselen vertoonden, door middel van centrifugeren in een dichtheidsgradiënt. Het materiaal werd bekeken in een elektronenmicroscoop en gefotografeerd. De gemiddelde lengte van de buigzame staafies van hetHippeastrum-mozaïekvirus, berekend uit 600 metingen, bedraagt 643±24 nm.     

Clinical features of ceroid lipofuscinosis in border collie dogs

Ceroid lipofuscinosis was diagnosed by histopathological and histochemical findings in 17 related border collie dogs and by clinical signs in 6 of their litter mates. Behavioural changes, first hyperactivity and later aggression, commenced at 16 to 23 (mean 19.5) months of age. Motor abnormalities and blindness were observed at the mean ages of 20.8 and 21.2 months, respectively. All dogs were euthanased 1 to 6 months after the onset of clinical signs, mean age 23.1 months. Pedigree data supported an autosomal recessive mode of inheritance.