Water resources assessment and management in drylands

Drylands regions of the world face difficult issues in maintaining water resources to meet current demands which will intensify in the future with population increases, infrastructure development, increased agricultural water demands, and climate change impacts on the hydrologic system. New water resources evaluation and management methods will be needed to assure that water resources in drylands are optimally managed in a sustainable manner. Development of water management and conservation methods is a multi-disciplinary endeavor. Scientists and engineers must collaborate and cooperate with water managers, planners, and politicians to successfully adopt new strategies to manage water not only for humans, but to maintain all aspects of the environment. This particularly applies to drylands regions where resources are already limited and conflicts over water are occurring. Every aspect of the hydrologic cycle needs to be assessed to be able to quantify the available water resources, to monitor natural and anthropogenic changes, and to develop flexible policies and management strategies that can change as conditions dictate. Optimal, sustainable water management is achieved by cooperation and not conflict, thereby necessitating the need for high quality scientific research and input into the processhttp://www.mdpi.com/2073-4441/8/6/239Published versio

Bounds on effective Majorana neutrino masses at HERA

The lepton-number violating process e p \to nu_e l l' X mediated by Majorana neutrinos is studied for the HERA collider for (l l') = (e tau), (mu tau), (mu mu) and (tau tau). Only the muonic decay of the tau is considered. The direct limit on the effective muon Majorana mass, is improved significantly to 4.0 times 10^3 GeV and for the first time direct limits on the analogous effective masses connected with the tau sector are given, namely 4.2 times 10^3 GeV for , 4.4 times 10^3 GeV for and 2.0 times 10^4 GeV for . We find that a more general analysis for an upgraded HERA could improve this values by a factor of up to 40, yet still being orders of magnitude worse than indirect limits.Comment: 9 pages, 4 figures, revised versio

Geothermal electricity generation and desalination: an integrated process design to conserve latent heat with operational improvements

A new process combination is proposed to link geothermal electricity generation with desalination. The concept involves maximizing the utilization of harvested latent heat by passing the turbine exhaust steam into a multiple effect distillation system and then into an adsorption desalination system. Processes are fully integrated to produce electricity, desalted water for consumer consumption, and make-up water for the geothermal extraction system. Further improvements in operational efficiency are achieved by adding a seawater reverse osmosis system to the site to utilize some of the generated electricity and using on-site aquifer storage and recovery to maximize water production with tailoring of seasonal capacity requirements and to meet facility maintenance requirements. The concept proposed conserves geothermally harvested latent heat and maximizes the economics of geothermal energy development. Development of a fully renewable energy electric generation-desalination-aquifer storage campus is introduced within the framework of geothermal energy development

Structure and Thermochemistry of Perrhenate Sodalite and Mixed Guest Perrhenate/Pertechnetate Sodalite.

Treatment and immobilization of technetium-99 (99Tc) contained in reprocessed nuclear waste and present in contaminated subsurface systems represents a major environmental challenge. One potential approach to managing this highly mobile and long-lived radionuclide is immobilization into micro- and meso-porous crystalline solids, specifically sodalite. We synthesized and characterized the structure of perrhenate sodalite, Na8[AlSiO4]6(ReO4)2, and the structure of a mixed guest perrhenate/pertechnetate sodalite, Na8[AlSiO4]6(ReO4)2-x(TcO4)x. Perrhenate was used as a chemical analogue for pertechnetate. Bulk analyses of each solid confirm a cubic sodalite-type structure (P4̅3n, No. 218 space group) with rhenium and technetium in the 7+ oxidation state. High-resolution nanometer scale characterization measurements provide first-of-a-kind evidence that the ReO4- anions are distributed in a periodic array in the sample, nanoscale clustering is not observed, and the ReO4- anion occupies the center of the sodalite β-cage in Na8[AlSiO4]6(ReO4)2. We also demonstrate, for the first time, that the TcO4- anion can be incorporated into the sodalite structure. Lastly, thermochemistry measurements for the perrhenate sodalite were used to estimate the thermochemistry of pertechnetate sodalite based on a relationship between ionic potential and the enthalpy and Gibbs free energy of formation for previously measured oxyanion-bearing feldspathoid phases. The results collected in this study suggest that micro- and mesoporous crystalline solids maybe viable candidates for the treatment and immobilization of 99Tc present in reprocessed nuclear waste streams and contaminated subsurface environments

Neutrino oscillation experiments and limits on lepton-number and lepton-flavor violating processes

Using a three neutrino framework we investigate bounds for the effective Majorana neutrino mass matrix. The mass measured in neutrinoless double beta decay is its (11) element. Lepton-number and -flavor violating processes sensitive to each element are considered and limits on branching ratios or cross sections are given. Those processes include $\mu^- e^+$ conversion, $K^+ \to \pi^- \mu^+ \mu^+$ or recently proposed high-energy scattering processes at HERA. Including all possible mass schemes, the three solar solutions and other allowed possibilities, there is a total of 80 mass matrices. The obtained indirect limits are up to 14 orders of magnitude more stringent than direct ones. It is investigated how neutrinoless double beta decay may judge between different mass and mixing schemes as well as solar solutions. Prospects for detecting processes depending on elements of the mass matrix are also discussed.Comment: 16 pages, 2 figure

Nuclear Anapole Moments

Nuclear anapole moments are parity-odd, time-reversal-even E1 moments of the electromagnetic current operator. Although the existence of this moment was recognized theoretically soon after the discovery of parity nonconservation (PNC), its experimental isolation was achieved only recently, when a new level of precision was reached in a measurement of the hyperfine dependence of atomic PNC in 133Cs. An important anapole moment bound in 205Tl also exists. In this paper, we present the details of the first calculation of these anapole moments in the framework commonly used in other studies of hadronic PNC, a meson exchange potential that includes long-range pion exchange and enough degrees of freedom to describe the five independent $S-P$ amplitudes induced by short-range interactions. The resulting contributions of pi-, rho-, and omega-exchange to the single-nucleon anapole moment, to parity admixtures in the nuclear ground state, and to PNC exchange currents are evaluated, using configuration-mixed shell-model wave functions. The experimental anapole moment constraints on the PNC meson-nucleon coupling constants are derived and compared with those from other tests of the hadronic weak interaction. While the bounds obtained from the anapole moment results are consistent with the broad ``reasonable ranges'' defined by theory, they are not in good agreement with the constraints from the other experiments. We explore possible explanations for the discrepancy and comment on the potential importance of new experiments.Comment: 53 pages; 10 figures; revtex; submitted to Phys Rev

Preparation and initial characterization of fluidized bed steam reforming pure-phase standards

Hanford is investigating the Fluidized Bed Steam Reforming (FBSR) process for their Low Activity Waste. The FBSR process offers a low-temperature continuous method by which liquid waste can be processed with the addition of clay into a sodium aluminosilicate (NAS) waste form. The NAS waste form is mainly comprised of nepheline (NaAlSiO{sub 4}), sodalite (Na{sub 8}[AlSiO{sub 4}]{sub 6}Cl{sub 2}), and nosean (Na{sub 8}[AlSiO{sub 4}]{sub 6}SO{sub 4}). Anions such as perrhenate (ReO{sub 4}{sup -}), pertechnetate (TcO{sub 4}{sup -}), and iodine (I{sup -}) are expected to replace sulfate in the nosean structure and/or chloride in the sodalite mineral structure (atomically bonded inside the aluminosilicate cages that these mineral structures possess). In the FBSR waste form, each of these phases can exist in a variety of solid solutions that differ from the idealized forms observed in single crystals in nature. The lack of understanding of the durability of these stoichiometric or idealized mineral phases complicates the ability to deconvolute the durability of the mixed phase FBSR product since it is a combination of different NAS phases. To better understand the behavior, fabrication and testing of the individual phases of the FBSR product is required. Analytical Development (AD) of the Science and Technology directorate of the Savannah River National Laboratory (SRNL) was requested to prepare the series of phase-pure standards, consisting of nepheline, nosean, and Cl, Re, and I sodalite. Once prepared, X-ray Diffraction (XRD) analyses were used to confirm the products were phase pure. These standards are being used for subsequent characterization studies consisting of the following: single-pass flow-through (SPFT) testing, development of thermodynamic data, and x-ray diffraction (XRD) calibration curves. In addition to the above mentioned phase-pure standards, AD was tasked with fabricating a mixed Tc-Re sodalite

Systematic decomposition of the neutrinoless double beta decay operator

We discuss the systematic decomposition of the dimension nine neutrinoless double beta decay operator, focusing on mechanisms with potentially small contributions to neutrino mass, while being accessible at the LHC. We first provide a (d = 9 tree-level) complete list of diagrams for neutrinoless double beta decay. From this list one can easily recover all previously discussed contributions to the neutrinoless double beta decay process, such as the celebrated mass mechanism or ¿exotics¿, such as contributions from left-right symmetric models, R-parity violating supersymmetry and leptoquarks. More interestingly, however, we identify a number of new possibilities which have not been discussed in the literature previously. Contact to earlier works based on a general Lorentz-invariant parametrisation of the neutrinoless double beta decay rate is made, which allows, in principle, to derive limits on all possible contributions. We furthermore discuss possible signals at the LHC for mediators leading to the short-range part of the amplitude with one specific example. The study of such contributions would gain particular importance if there were a tension between different measurements of neutrino mass such as coming from neutrinoless double beta decay and cosmology or single beta decay

Stability mechanisms of a thermophilic laccase probed by molecular dynamics.

Laccases are highly stable, industrially important enzymes capable of oxidizing a large range of substrates. Causes for their stability are, as for other proteins, poorly understood. In this work, multiple-seed molecular dynamics (MD) was applied to a Trametes versicolor laccase in response to variable ionic strengths, temperatures, and glycosylation status. Near-physiological conditions provided excellent agreement with the crystal structure (average RMSD ∼0.92 Å) and residual agreement with experimental B-factors. The persistence of backbone hydrogen bonds was identified as a key descriptor of structural response to environment, whereas solvent-accessibility, radius of gyration, and fluctuations were only locally relevant. Backbone hydrogen bonds decreased systematically with temperature in all simulations (∼9 per 50 K), probing structural changes associated with enthalpy-entropy compensation. Approaching T opt (∼350 K) from 300 K, this change correlated with a beginning "unzipping" of critical β-sheets. 0 M ionic strength triggered partial denucleation of the C-terminal (known experimentally to be sensitive) at 400 K, suggesting a general salt stabilization effect. In contrast, F(-) (but not Cl(-)) specifically impaired secondary structure by formation of strong hydrogen bonds with backbone NH, providing a mechanism for experimentally observed small anion destabilization, potentially remedied by site-directed mutagenesis at critical intrusion sites. N-glycosylation was found to support structural integrity by increasing persistent backbone hydrogen bonds by ∼4 across simulations, mainly via prevention of F(-) intrusion. Hydrogen-bond loss in distinct loop regions and ends of critical β-sheets suggest potential strategies for laboratory optimization of these industrially important enzymes

Consuming Two Eggs per Day, as Compared to an Oatmeal Breakfast, Increases Plasma Ghrelin while Maintaining the LDL/HDL Ratio

Eggs contain high quality protein, vitamins, minerals and antioxidants, yet regular consumption is still met with uncertainty. Therefore, the purpose of this study was to compare the effects of consuming two eggs per day or a heart-healthy oatmeal breakfast on biomarkers of cardiovascular disease (CVD) risk and satiety measures in a young, healthy population. Fifty subjects participated in a randomized crossover clinical intervention; subjects were randomly allocated to consume either two eggs or one packet of oatmeal per day for breakfast for four weeks. After a three-week washout period, participants were allocated to the alternative breakfast. Fasting blood samples were collected at the end of each intervention period to assess plasma lipids and plasma ghrelin. Subjects completed visual analog scales (VAS) concurrent to dietary records to assess satiety and hunger. Along with an increase in cholesterol intake, there were significant increases in both low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol following the egg consumption period (p \u3c 0.01). However, there was no difference in the LDL/HDL ratio, a recognized biomarker of CVD risk, nor in the plasma glucose, triglycerides or liver enzymes, between diet periods. Several self-reported satiety measures were increased following the consumption of eggs, which were associated with lower plasma ghrelin concentrations (p \u3c 0.05). These results demonstrate that compared to an oatmeal breakfast, two eggs per day do not adversely affect the biomarkers associated with CVD risk, but increase satiety throughout the day in a young healthy population