Compilation of critical element papers for principalship cohort

The most important role of an educational leader is the leader of instruction. It is crucial that you implement a quality atmosphere within your school that is conducive to high quality instruction. It is also essential that the curriculum being taught in the classrooms is rigorous and relevant to the students. If the material is not relevant, the student will struggle to understand the importance of learning the material. If the curriculum is not rigorous, schools are not doing their job of challenging and pushing students to excel at the highest levels

High-resolution ice nucleation spectra of sea-ice bacteria: implications for cloud formation and life in frozen environments

International audienceEven though studies of Arctic ice forming particles suggest that a bacterial or viral source derived from open leads could be important for cloud formation in the Arctic (Bigg and Leck, 2001), the ice nucleation potential of most polar marine psychrophiles or viruses has not been examined under conditions more closely resembling those in the atmosphere. In this paper, we examined the ice nucleation activity (INA) of several representative Arctic and Antarctic sea-ice bacterial isolates and a polar Colwellia phage virus. High-resolution ice nucleation spectra were obtained for droplets containing bacterial cells or virus particles using a free-fall freezing tube technique. The fraction of frozen droplets at a particular droplet temperature was determined by measuring the depolarized light scattering intensity from solution droplets in free-fall. Our experiments revealed that all sea-ice isolates and the virus nucleated ice at temperatures very close to the homogeneous nucleation temperature for the nucleation medium ? which for artificial seawater was ?42.2±0.3°C. Our results indicated that these marine psychro-active bacteria and viruses are not important for heterogeneous ice nucleation processes in sea ice or polar clouds. These results also suggested that avoidance of ice formation in close proximity to cell surfaces might be one of the cold-adaptation and survival strategies for sea-ice bacteria. The fact that INA occurs at such low temperature could constitute one factor that explains the persistence of metabolic activities at temperatures far below the freezing point of seawater

Catalytic hydrogenation of carboxylic acid esters, amides, and nitriles with homogeneous catalysts

This review describes the catalytic reduction of amides, carboxylic acid esters and nitriles with homogeneous catalysts using molecular hydrogen as an environmental friendly reducing agent

Hypercontractivity on the qq-Araki-Woods algebras

Extending a work of Carlen and Lieb, Biane has obtained the optimal hypercontractivity of the $q$-Ornstein-Uhlenbeck semigroup on the $q$-deformation of the free group algebra. In this note, we look for an extension of this result to the type III situation, that is for the $q$-Araki-Woods algebras. We show that hypercontractivity from $L^p$ to $L^2$ can occur if and only if the generator of the deformation is bounded.Comment: 17 page

Selective reductive amination of aldehydes from nitro compounds catalyzed by molybdenum sulfide clusters

Secondary amines are selectively obtained from low value starting materials using hydrogen and a non-noble metal-based catalyst. The reductive amination of aldehydes from nitroarenes or nitroalkanes is efficiently catalyzed by a well-defined diamino molybdenum sulfide cluster in a one-pot homogeneous reaction. The integrity of the molecular cluster catalyst is preserved along the process

Optimally coherent sets in geophysical flows: A new approach to delimiting the stratospheric polar vortex

The "edge" of the Antarctic polar vortex is known to behave as a barrier to the meridional (poleward) transport of ozone during the austral winter. This chemical isolation of the polar vortex from the middle and low latitudes produces an ozone minimum in the vortex region, intensifying the ozone hole relative to that which would be produced by photochemical processes alone. Observational determination of the vortex edge remains an active field of research. In this letter, we obtain objective estimates of the structure of the polar vortex by introducing a new technique based on transfer operators that aims to find regions with minimal external transport. Applying this new technique to European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-40 three-dimensional velocity data we produce an improved three-dimensional estimate of the vortex location in the upper stratosphere where the vortex is most pronounced. This novel computational approach has wide potential application in detecting and analysing mixing structures in a variety of atmospheric, oceanographic, and general fluid dynamical settings

The development of a natural plankton population in an outdoor tank with nutrient-poor sea water. II. Changes in dissolved carbohydrates and amino acids

terrelations between plankton communities and dissolved carbohydrates and amino acids were investigated under near-natural conditions in sea water enclosed in plastic tanks. In summer 1972 the development of a natural plankton population was followed in a 3-m3 plastic tank for 28 d. In the course of this experiment, concentrations of dissolved neutral carbohydrates and free amino acids were determined. Results are in the range of published data for the open sea with respect to concentrations (0.2-2.5 pnoles dm-3 total sugar; 0.2-3.1 pnoles dm3 total amino acids) and qualitative composition. A plankton succession was observed during the experiment; this was accompanied by distinct alterations in the concentrations of dissolved amino acids and carbohydrates. Glucose and lysine occurred in highest concentrations. Maximum rate of increase was 29 nmoles dm3 h-' for glucose, and 25 nmoles dm3 h-' for lysine. The rates of decrease are in the same range as bacterial uptake rates determined by various authors employing tracer methods. Numerous positive, highly significant correlations suggest heteropoly- saccharides as one source of individual carbohydrates. Relations between certain species within the plankton succession and occurrence of dissolved organic substances were observed. Significant positive correlations existed between glucose and diatoms as well as between glucose, galactose, mannose, arabinose and ribose and phytoplankton biomass. There were also several significant positive correlations of amino acids, especially of valine, leucine and isoleucine with other biological parameters

Gray and white matter astrocytes differ in basal metabolism but respond similarly to neuronal activity

Astrocytes are a heterogeneous population of glial cells in the brain, which adapt their properties to the requirements of the local environment. Two major groups of astrocytes are protoplasmic astrocytes residing in gray matter as well as fibrous astrocytes of white matter. Here, we compared the energy metabolism of astrocytes in the cortex and corpus callosum as representative gray matter and white matter regions, in acute brain slices taking advantage of genetically encoded fluorescent nanosensors for the NADH/NAD+ redox ratio and for ATP. Astrocytes of the corpus callosum presented a more reduced basal NADH/NAD+ redox ratio, and a lower cytosolic concentration of ATP compared to cortical astrocytes. In cortical astrocytes, the neurotransmitter glutamate and increased extracellular concentrations of K+, typical correlates of neuronal activity, induced a more reduced NADH/NAD+ redox ratio. While application of glutamate decreased [ATP], K+ as well as the combination of glutamate and K+ resulted in an increase of ATP levels. Strikingly, a very similar regulation of metabolism by K+ and glutamate was observed in astrocytes in the corpus callosum. Finally, strong intrinsic neuronal activity provoked by application of bicuculline and withdrawal of Mg2+ caused a shift of the NADH/NAD+ redox ratio to a more reduced state as well as a slight reduction of [ATP] in gray and white matter astrocytes. In summary, the metabolism of astrocytes in cortex and corpus callosum shows distinct basal properties, but qualitatively similar responses to neuronal activity, probably reflecting the different environment and requirements of these brain regions