Ambient-temperature isolation of a compound with a boron-boron triple bond

Homoatomic triple bonds between main-group elements have been restricted to alkynes, dinitrogen, and a handful of reactive compounds featuring trans-bent heavier elements of groups 13 and 14. Previous attempts to prepare a compound with a boron-boron triple bond that is stable at ambient temperature have been unsuccessful, despite numerous computational studies predicting their viability. We found that reduction of a bis(N-heterocyclic carbene)-stabilized tetrabromodiborane with either two or four equivalents of sodium naphthalenide, a one-electron reducing agent, yields isolable diborene and diboryne compounds. Crystallographic and spectroscopic characterization confirm that the latter is a halide-free linear system containing a boron-boron triple bond.     

Mustelidae are natural hosts of Staphylococcus delphini group A

According to the current taxonomy, the Staphylococcus intermedius group (SIG) comprises of at least three distinct species. While S. intermedius and S. pseudintermedius are associated with specific hosts (pigeons and dogs, respectively), the natural host of S. delphini remains unclear. We analysed 158 SIG isolates from less studied animal species belonging to the order Carnivora, including mink (n=118), fox (n=33), badger (n=6) and ferret (n=1). Species identification was performed by nuc PCR in combination with sodA sequence analysis and pta PCR restriction fragment length polymorphism (RFLP). The results showed a consistent association between host and bacterial species. All isolates from minks, ferret and badgers belonged to S. delphini group A, whereas all fox isolates except one were identified as S. pseudintermedius. The remaining fox isolate belonged to S. delphini group A. The results indicate that Mustelidae such as minks, ferrets and badgers are natural hosts of S. delphini group A. This is in contrast with Canidae, which are primarily colonized and infected with S. pseudintermedius. These findings suggest that coagulase-positive staphylococcal species may have evolved and diverged through host adaptation.     

Genetic data from avian influenza and avian paramyxoviruses generated by the European network of excellence (EPIZONE) between 2006 and 2011--review and recommendations for surveillance

Since 2006, the members of the molecular epidemiological working group of the European "EPIZONE" network of excellence have been generating sequence data on avian influenza and avian paramyxoviruses from both European and African sources in an attempt to more fully understand the circulation and impact of these viruses. This review presents a timely update on the epidemiological situation of these viruses based on sequence data generated during the lifetime of this project in addition to data produced by other groups during the same period. Based on this information and putting it all into a European context, recommendations for continued surveillance of these important viruses within Europe are presented.     

High-frequency analysis of the complex linkage between soil CO(2) fluxes, photosynthesis and environmental variables

High-frequency soil CO(2) flux data are valuable for providing new insights into the processes of soil CO(2) production. A record of hourly soil CO(2) fluxes from a semi-arid ponderosa pine stand was spatially and temporally deconstructed in attempts to determine if variation could be explained by logical drivers using (i) CO(2) production depths, (ii) relationships and lags between fluxes and soil temperatures, or (iii) the role of canopy assimilation in soil CO(2) flux variation. Relationships between temperature and soil fluxes were difficult to establish at the hourly scale because diel cycles of soil fluxes varied seasonally, with the peak of flux rates occurring later in the day as soil water content decreased. Using a simple heat transport/gas diffusion model to estimate the time and depth of CO(2) flux production, we determined that the variation in diel soil CO(2) flux patterns could not be explained by changes in diffusion rates or production from deeper soil profiles. We tested for the effect of gross ecosystem productivity (GEP) by minimizing soil flux covariance with temperature and moisture using only data from discrete bins of environmental conditions (±1 °C soil temperature at multiple depths, precipitation-free periods and stable soil moisture). Gross ecosystem productivity was identified as a possible driver of variability at the hourly scale during the growing season, with multiple lags between ~5, 15 and 23 days. Additionally, the chamber-specific lags between GEP and soil CO(2) fluxes appeared to relate to combined path length for carbon flow (top of tree to chamber center). In this sparse and heterogeneous forested system, the potential link between CO(2) assimilation and soil CO(2) flux may be quite variable both temporally and spatially. For model applications, it is important to note that soil CO(2) fluxes are influenced by many biophysical factors, which may confound or obscure relationships with logical environmental drivers and act at multiple temporal and spatial scales; therefore, caution is needed when attributing soil CO(2) fluxes to covariates like temperature, moisture and GEP.     

A study of the comparative anatomy of the brain of domestic ruminants using magnetic resonance imaging

Although magnetic resonance imaging has been used to examine the brain of domestic ruminants, detailed information relating the precise anatomical features in these species is lacking. In this study the brain structures of calves (Bos taurus domesticus), sheep (Ovis aries), goats (Capra hircus) and a mesaticephalic dog (Canis lupis familiaris) were examined using T2-weighed Turbo Spin Echo sequences; three-dimensional models based on high-resolution gradient echo scans were used to identify brain sulci and gyri in two-dimensional images. The ruminant brains examined were similar in structure and organisation to those of other mammals but particular features included the deep depression of the insula and the pronounced gyri of the cortices, the dominant position of the visual (optic nerve, optic chiasm and rostral colliculus) and olfactory (olfactory bulb, olfactory tracts and piriform lobe) systems, and the relatively large size of the diencephalon.     

Porencephaly in dogs and cats: magnetic resonance imaging findings and clinical signs

Magnetic resonance imaging (MRI) features of brain lesions in 5 dogs and 2 cats characterized by extensive cystic changes of the cerebral hemispheres in terms of a porencephaly are presented. Age at diagnosis ranged from 12 weeks to 7 years. MRI findings were confined to the forebrain. Porencephalic lesions appeared as wedge-shaped parenchymal defects connecting the ventricular system and the subarachnoid space or as large cystic defects in the cerebral hemispheres. Although in two adult dogs the porencephalic lesions were asymptomatic, the other animals showed clinical symptoms depending on the affected cerebral area. Three animals had seizures. Interestingly, four animals showed neurological signs normally not localized to the forebrain (nystagmus, hypermetria, ataxia). Whether these clinical signs are related to impaired function of the cerebral cortex or to not recognizable lesions in the cerebello-vestibular system could not be further clarified. Although the defects develop intrauterine or postnatal, the clinical symptoms can occur later in life. The definition of porencephaly as well as its subclassification is not uniform in veterinary medicine. We suggest the term encephaloclastic porencephaly unregarding the underlying cause of the defect, which cannot be further specified by diagnostic imaging.     

Does Cattle Grazing Affect Ant Abundance and Diversity in Temperate Grasslands?

Half of the world's land base is grazed by domesticated livestock. Because of the important functional role of ants in grasslands, it is important to understand the effect of livestock grazing on ant abundance and diversity. The objectives of this study were to examine the effect of cattle grazing and site productivity on the abundance, species richness, and species diversity of ants in Lac du Bois Grasslands Provincial Park, British Columbia, Canada. We hypothesized that the measured ant variables would be lowest in grazed areas and at low site productivity. Pitfall trapping was conducted at four sites: two at each low and high site productivity levels. At each site an ungrazed (fenced exclosure) and grazed transect was sampled during May, July, and August of 2008. Captured ants were preserved in ethanol and identified. Eight genuses of ants were collected: Tapinoma, Camponotus, Formica, Lasius, Aphaenogaster, Myrmica, Solinopsis, and Temnotharox. The mean number of ants per pitfall was higher at high site productivity sites that were grazed (15.10 ±  SE) compared to high productivity sites ungrazed (3.28 ±  SE); grazing at low productivity reduced numbers of ants from 5.07 (± 0.70 SE) to 2.20 (± 0.39 SE) (F = 21.806; P [ 0.001). Tapinoma sessile and A. occidentalis had the greatest numbers in the pitfall traps. Species richness (F = 23.330, P [ 0.001) and diversity (F = 11.764, P = 0.001) followed a similar trend. Because productivity and cattle grazing affect ant diversity and abundance, and ants impact ecosystem functioning, these factors should be considered in management of grasslands.     

Regulation of Insulin Action by Diet and Exercise

The regulation of the cellular actions of the hormone insulin is essential to the maintenance of macronutrient metabolism, body weight regulation, and a surprisingly diverse range of other integrative physiologic functions. Because of the diverse targets of insulin action, any dysfunction in insulin is likely to have systemic consequences. Although type 1 and type 2 diabetes are the most obvious clinical consequences of impaired insulin synthesis and insulin action, respectively, there are also subclinical disorders that attend defects in the function of insulin. In humans and horses, the “metabolic syndrome” is characterized by a cluster of metabolic sequelae that arise as a result of insulin resistance. Importantly, both diet and exercise can regulate insulin action and can thus be leveraged as treatment tools to prevent and treat the metabolic syndrome. The aim of this review is to characterize the integrative biology of insulin action and to describe the role of diet and exercise in regulating tissue responsiveness to insulin.     

A multiscale soil–landform relationship in the glacial‐drift area based on digital terrain analysis and soil attributes

Understanding the linkages between structure and processes in soil landscapes involves analyses across several spatial and temporal scales. The transfer of information between scales requires the (1) identification of respective scale levels and (2) procedures for regionalization. Here, we present a multiparameter delineation of landform units and their attribution with typical Reference Soil Groups (RSG) of a landscape of NE Germany which is representative of young moraine regions. Data sources are a digital elevation model (DEM, 5 m × 5 m), a reference data set from sections of an intensively augered landscape, and expert knowledge. A conceptual digital soil map was constructed in the scale 1:5000 based on the Topographic Position Index (TPI). The methodology is applicable for multiscale analyses. Results are (1) the landform unit classified by digital terrain analysis of a DEM, (2) the attribution of RSG, and (3) the evaluation of the classification. Accuracy of the method was 57% overall, with 70% accuracy on typical erosional sites. The developed method allows identification of terrain‐related soil pattern with high spatial resolution in glacial‐drift areas. The high resolution of soil information can be used for delineation of management zones in precision farming, or as input for process studies and models requiring a translation of typological soil information into relevant soil properties (e.g., by pedotransfer functions).