Artinian algebras and Jordan type

The Jordan type of an element $\ell$ of the maximal ideal of an Artinian k-algebra A acting on an A-module M of k-dimension n, is the partition of n given by the Jordan block decomposition of the multiplication map $m_\ell$ on M. In general the Jordan type has more information than whether the pair $(\ell,M)$ is strong or weak Lefschetz. We develop basic properties of the Jordan type and their loci for modules over graded or local Artinian algebras. We as well study the relation of generic Jordan type of $A$ to the Hilbert function of $A$. We introduce and study a finer invariant, the Jordan degree type. In our last sections we give an overview of topics such as the Jordan types for Nagata idealizations, for modular tensor products, and for free extensions, including examples and some new results. We as well propose open problems.Comment: 53 pages. Added results, examples for Jordan degree type (Section 2.4) and Jordan type and initial ideal (Section 2.5

Promissing cerium-doped barium manganate perovskite for solar thermochemical hydrogen production

Over the past decade, nonstoichiometric oxides have been investigated for solar thermochemical water splitting applications because of their ability to partially reduce and create oxygen vacancies at high temperatures and subsequently reoxidize in steam at lower temperatures, uptaking the oxygen into the lattice and producing hydrogen as a consequence (c.f. Figure 1a). Cerium oxide is currently viewed as the leading candidate for this process because of its fast reoxidation reaction kinetics and considerable H2 yield. However, high temperatures (\u3e1550oC) are required to drive ceria reduction, making the reactor and the solar heat collector design challenging. Furthermore, a low steam oxidation temperature is preferred from a reactor energy balance stand-point. Please click Additional Files below to see the full abstract

River Otter in Arkansas. IV. Winter Food Habits in Eastern Arkansas

Stomachs and intestines of 89 river otters (Lutra canadensis) collected in eastern Arkansas during the trapping seasons (December- January) of 1978-1983 were examined for food remains. Fish (primarily centrarchids, catostomids, and clupeids) dominated the diet (71.2%). The next most abundant prey was crayfish (18.3% of the diet). Other foods included gray squirrel (Sciurus carolinensis), wood duck (Aixsponsa), snakes (Thamnophis proximus), frogs (Ranidae and Hylidae), and beetles (Coleoptera)

Sunshine to petrol: Thermochemistry for solar fuels

Sandia National Laboratories has for many years been engaged in investigating and developing the science and technology of solar thermochemistry for application to production of solar fuels (“Sunshine to Petrol”), and thermochemical energy storage. The vision of Sunshine to Petrol is captured in one deceptively simple chemical equation: Solar Energy + xCO2 + (x+1) H2O → CxH2x+2 (liquid fuel) + (1.5x+0.5) O2 Practical implementation of this equation may seem far-fetched, since it effectively describes the use of solar energy to reverse combustion. However, it is also representative of the photosynthetic processes responsible for much of life on earth and, as such, summarizes the biomass approach to fuels production. Our analysis indicates that any such solar-driven conversion process must operate at a relatively high efficiency, at least 10% solar-to-fuel, to meet the dictates of economics and scale. Thus, it is our contention that an alternative that is not limited by the efficiency of photosynthesis and that more directly leads to a liquid fuel is required. The approach we have pursued is the direct application of solar thermal energy to split carbon dioxide and water to obtain carbon monoxide and hydrogen, the basic precursors to synthetic fuels. These conversions are accomplished via two-step metal-oxide based thermochemical cycles (Figure 1.) In one step of the thermochemical cycle, a metal oxide (MOx) is thermally reduced (oxygen is evolved) at high temperatures driven by concentrating solar power; in the other step the oxygen-deficient (MOx-d) material is reoxidized with carbon dioxide (or water) at a lower temperature to restore the material to its original state and to yield carbon monoxide (or hydrogen). As shown in the figure, heat may be recuperated between the high and low temperature steps. Figure 1 – Schematic depiction of a two-step metal-oxide thermochemical cycle with internal recuperation for carbon dioxide and water splitting. Thermochemistry promises to provide the high efficiencies that we believe are required for solar fuels. However, the continuous chemical and thermal cycling occurring in these cyclic processes poses numerous chemistry, materials, and engineering challenges. Improvements in both the metal oxides that facilitate the conversion, and the reactors and systems in which they are implemented, are needed to realize high efficiency and reliable operation. The properties that define an ideal material for an efficient process, e.g. the thermodynamics of the redox reaction, and key materials traits for implementation will be discussed. Advances in characterizing and understanding the remarkably dynamic behavior of some of the known active materials will also be presented. Requirements and constraints for efficient design and operation of solar thermochemical reactors will likewise be introduced. Results for an established material, i.e. ceria, in a first-of-kind continuous reactor for on-sun conversion of carbon dioxide to carbon monoxide over a period of days will be presented. Next-generation approaches to materials and reactors will be briefly discussed. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000

Perceived protein needs and measured protein intake in collegiate male athletes: an observational study

<p>Abstract</p> <p>Background</p> <p>Protein needs for athletes are likely higher than those for the general population. However, athletes may perceive their protein needs to be excessively high. The purpose of this research was to compare collegiate athletes' perceived protein needs and measured protein intake to the recommended protein intake (RDI) for healthy adults (i.e. 0.8 g/kg/d) and to the maximum beneficial level for strength-trained athletes (i.e. 2.0 g/kg/day).</p> <p>Methods</p> <p>Perceived protein needs were quantified in 42 strength-trained collegiate male athletes by using a survey that asked the athletes to provide their perception about protein needs in specific quantitative terms (i.e. g/kg/d). Perceived protein needs were also determined by having the athletes select a daylong menu that they perceived to have adequate protein content from a collection of 5 isoenergetic menus, which differed in terms of protein content. Actual protein intake was quantified using 3-day food records and nutrient analysis. Single sample t-tests were used to compare protein intake and perceived protein needs to 0.8 g/kg/day and 2.0 g/kg/day.</p> <p>Results</p> <p>When asked to provide, in quantitative terms, protein needs for athletes, 67% of the athletes indicated "do not know." Of the remaining 33% of athletes, all gave values greater than 2.0 g/kg/d (mean 21.5 ± 11.2 g/kg/d, p = 0.14 vs. 2.0 g/kg/d). Based on the menu selection method for determining perceived protein needs, the athletes indicated that their protein needs were 2.4 ± 0.2 g/kg/d, which was greater than the RDI for protein (p < 0.0001) and tended to be greater than the maximally beneficial protein intake of 2.0 g/kg/d (p = 0.13). Measured protein intake was 2.0 ± 0.1 g/kg/d, which was greater than the RDI (p < 0.0001) but not different from the maximally beneficial protein intake of 2.0 g/kg/d (p = 0.84).</p> <p>Conclusions</p> <p>Male collegiate athletes recognize that their protein needs are higher than that of the general population and consume significantly more protein than recommended in the RDI. However, it also appears that athletes are not aware of objective recommendations for protein intake and may perceive their needs to be excessively high. This study highlights the need for nutrition education in collegiate athletes, in particular nutrition education on macronutrient distribution and protein needs.</p

Highly Enhanced Concentration and Stability of Reactive Ce^3+ on Doped CeO_2 Surface Revealed In Operando

Trivalent cerium ions in CeO_2 are the key active species in a wide range of catalytic and electro-catalytic reactions. We employed ambient pressure X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy to quantify simultaneously the concentration of the reactive Ce^3+ species on the surface and in the bulk of Sm-doped CeO_2(100) in hundreds of millitorr of H2–H2O gas mixtures. Under relatively oxidizing conditions, when the bulk cerium is almost entirely in the 4+ oxidation state, the surface concentration of the reduced Ce^3+ species can be over 180 times the bulk concentration. Furthermore, in stark contrast to the bulk, the surface’s 3+ oxidation state is also highly stable, with concentration almost independent of temperature and oxygen partial pressure. Our thermodynamic measurements reveal that the difference between the bulk and surface partial molar entropies plays a key role in this stabilization. The high concentration and stability of reactive surface Ce^3+ over wide ranges of temperature and oxygen partial pressure may be responsible for the high activity of doped ceria in many pollution-control and energy-conversion reactions, under conditions at which Ce^3+ is not abundant in the bulk