bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of the Supercontainer Design for Deep Geological Disposal of High-Level Heat Emitting Radioactive Waste in Belgium
Authors: Bel Johan J.P. , Wickham Stephen M. , Gens Robert M.F.
Published: April 2011

ONDRAF-NIRAS has recently selected a Supercontainer with a Portland Cement (PC) buffer as the preferred new reference design for disposal of HLW and spent fuel. The selection process involved a multi-criteria analysis of alternative design options, which were evaluated against a range of long-term safety and feasibility criteria. A PC concrete has been chosen for the buffer because this will provide a highly alkaline chemical environment, which will last for thousands of years. In this environment the external surface of the overpack will be passivated and overpack corrosion will be inhibited. The concrete buffer also has low-hydraulic conductivity to slow the infiltration of external fluids to the overpack surface, and provides radiological shielding.

ONDRAF-NIRAS has made a preliminary evaluation of the viability of the reference Supercontainer design. The following areas were reviewed and investigated: radiolysis, thermo-hydraulic (TH) behaviour of the concrete buffer, metal corrosion, the chemical and mineralogical evolution of the concrete buffer, and relevant industrial experience. This paper describes the main findings, and identifies remaining design and performance uncertainties. Prioritisation and recommendations for future work are also given.
Development of an Uncertainty Analysis Methodology Associated with the Characterization of the Geological Environment: Study on its Applicability in the Tono area
Authors: Yanagizawa K. , Takeda S. , Osawa H. , Suyama Y. , Takase H. , Toida M. , Metcalfe R.
Published: April 2011

JNC has developed an uncertainty analysis methodology for application to the spatially heterogeneous characteristics of a geological environment. The developed methodology adopts a new approach that identifies all the possible options in concepts and parameter ranges that cannot be excluded in the light of evidence available. This approach enables uncertainties associated with the understanding at a given stage of the site characterization to be made explicit, using probability theory and possibility theory. The uncertainties could be reduced by screening, to exclude concepts and parameter ranges that can be denied in the light of additional evidence obtained in subsequent investigation stages. This paper describes an outline of the developed methodology and its applicability in the Tono area.
Europium migration in Argilaceous Rocks : on the use of Micro Laser-Induced Breakdown Spectroscopy (micro LIBS) as a Microanalysis Tool
Authors: Menut Denis , Descostes Michael , Meier Patrick , Radwan Jean , Mauchien Patrick , Poinssot Christophe
Published: April 2011

Eu migration in a Callovo-Oxfordian argilite sample was studied using the micro LIBS technique. Quantitative elemental mapping were made by micro LIBS that showed the actual distribution of the various micro areas observed on the Callovo-Oxfordian sample's surface. Calcite, dolomite, alumino-silicates, quartz, pyrite and iron oxides were identified and their statistical distribution was determined. Experimental Eu profiles observed are consistent with diffusion process accompanied by heterogeneous sorption on alumino-silicate surface.
Research in actinide geochemistry: Do we need speciation information at the molecular level?
Authors: Geckeis Horst
Published: April 2011

Radionuclide sorption to rock or sediment surfaces in the vicinity of a nuclear waste reposi-tory contributes significantly to the overall safety performance of a given disposal concept. State-of-the-artspeciation techniques as laser - and X-ray spectroscopy are becoming more and more involved into the elucidation of sorption mechanisms and to the quantification of surface speciation. They are extremely valuable tools to gain fundamental understanding as a basis for the development of geochemical sorption models which in turn are needed to predict ra-dionuclide behaviour in the environment.
Carbon Steel Canister Performance Assessment: Iron Transfer Study
Authors: Vokál Antonín , Lukin Dmitrij , Vopálka Dušan
Published: April 2011

Carbon steel has been chosen in the Czech disposal concept of spent fuel disposal in a granite host rock as a reference material for disposal canisters. On the basis of the results of performance assessment studies, it could be decided whether this material is suitable or whether a more corrosion resistant, and also more expensive, material should substitute it. A number of papers have convincingly shown that iron transfer constraints contribute to a significant decrease in corrosion rate, but no study hasso far been devoted to modeling this process. In this paper the effects of initial corrosion rate, corrosion product solubility and porosity and other repository parameters on the transfer of iron to the host rock are modeled using a numerical transport computer code. It was found that the critical parameter for iron transfer is the solubility of corrosion products, considerably affecting the steady state corrosion rate. The initial corrosion rate of carbon steel and the sorption properties of bentonite primarily affect the time needed to achieve a steady state of corrosion. The results of the calculations strongly suggest that the constraints on iron transfer from the canister surface will govern the corrosion rate of carbon steel canisters, whose lifetime, owing to this effect, can stretch to millions of years.
Corrosion of Copper Canisters Through Microbially Mediated Sulphate Reduction
Authors: Sidborn Magnus , Neretnieks Ivars
Published: April 2011

A biogeochemical model was developed with an aim to illustrate the transport and reaction processes that may be involved in copper canister corrosion by sulphide in a deep repository for nuclear waste. Sulphide concentrations in the groundwaters in Sweden are relatively low and are generally considered to be of little importance for corrosion of the copper canisters. Sulphate, however, is present in relatively large amounts (50-700 mg/L) and may be reduced to sulphide by reaction with organic matter. Mediated by microbes, the reduction rate may be increased considerably compared to abiotic reduction. Microbially mediated sulphate reduction occurs in many natural environments, provided that reactive organic matter is available. Groundwater analyses indicate relatively high concentrations of dissolved methane (up to 16 mg/L) which thermodynamically is a suitable reducing agent. This processes could occur in fractures inthe bedrock provided that substrates are continuously supplied and that there is a sink for the reaction products. In the repository, the copper canisters may provide a sink for sulphide that yields a favourable environment for the microbe population. The model domain includes a canister with surrounding backfill material intersected by a hydraulically conductive fracture. Transport of substrates and reaction products in the fracture and backfillas well as microbially mediated reaction at the fracture opening is included in the model. Results indicate that microbially produced sulphide could potentially contribute to canister corrosion.
The Diffusion of Radionuclides through Waste Encapsulation Grouts
Authors: Chambers Adam V. , Green Andrew , Harris Andrew W. , Heath Timothy G. , Hunter Fiona M.I. , Manning Michelle C. , Williams Stephen J.
Published: April 2011

United Kingdom Nirex Limited develops and advises on safe, environmentally sound and publicly acceptable options for the long-term management of radioactive waste. One option Nirex has developed is a phased geological repository concept for intermediate level waste and some low level wastes that makes use of a combination of engineered and natural barriers. Physical containment of radionuclides would be achieved by immobilisation and packaging of wastes (mostly) in stainless steel containers.

Existing models of the migration of dissolved radionuclides from packaged wastes suggest that radionuclide release is determined largely by the rate of diffusion through the encapsulation grout used to immobilise the waste. The use of such models requires diffusion coefficient data for radionuclides in waste encapsulation grouts. This paper describes a programme of through-diffusion experiments, and modelling interpretation, aimed at deriving diffusion coefficients for some radionuclides in two types of encapsulation grout.

An intrinsic diffusion coefficient of HTO of around 1×10−13 to 2×10−13 m2s−1 was determined for a 3:1 mix of blast furnace slag to ordinary Portland cement, compared to around 4×10−13 to 5×10−13 m2s−1 for a 3:1 mix of pulverised fuel ash to ordinary Portland cement. These values are lower than that assumed for a non-sorbing radionuclide in an earlier modelling exercise. Porosity values around 0.3 were obtained in each case. For 36Cl as chloride, the experiments showed no significant breakthrough over the experimental timescale of about one year, suggesting an intrinsic diffusion coefficient below 5×10−13 m2s−1. One possibility is that chlorine-containing solids are precipitating in the cement. An intrinsic diffusion coefficient for 137Cs in the 3:1 mix of pulverised fuel ash to ordinary Portland cement of 4×10−15 m2s−1 was estimated, significantly lower than that determined for HTO.

The results from three of the sixteen experiments could not be fitted with a simple diffusion model, and for a further five experiments there was some doubt as to whether simple diffusion behaviour had been observed. It is suggested that this may have been due to cracks in the grouts that were sufficiently large to affect the diffusion properties of the grouts, although none was visible to the naked eye. Cracking of the waste encapsulation grouts could provide a mechanism for enhanced migration of radionuclides from waste packages, compared with diffusion in a homogeneous porous medium alone.
Mixed Organic and Mineral Waste Processing by Incineration-Vitrification : Case of Bituminous Media
Authors: Girold Christophe , Pinet Olivier , Lemort Florent
Published: April 2011

Burnable radioactive waste management options are often in favour of the vitrification due to their volume reduction, resulting in cost saving for transport and storage. More, the interest is also to obtain a best radioactivity immobilization in a long-lasting matrix. Development made on incineration-vitrification process must take into account radioactivity environment in term of process compactness, gas treatment and secondary wastes. A new and simplified equipment, using thermal oxygen plasma coupled with a cold crucible melter, is being developed at the Valrho-Marcoule nuclear centre (France) : SHIVA, for Advanced Hybrid System for Incineration and Vitrification. As part of studies concerning the management of bitumen canisters stored in Marcoule, the feasibility of their treatment in an incineration-vitrification process have been tested. This treatment could concern the most radioactive bituminised waste drums because they have to be sent in a costly storage site in consideration of their radioactivity. The interest of such treatment is first to reduce the volume of wastes in order to appreciably diminish the cost of this storage.
Preservation of Archaeological Materials in Arid Environments: Analogues Relevant to Yucca Mountain
Authors: Chapman Neil , Dansie Amy , McCombie Charles
Published: April 2011

The potential repository at Yucca Mountain in Nevada is in an arid area, in unsaturated volcanic tuff with oxidising conditions, and may be kept open and ventilated for hundreds of years. Existing US work on archaeological material and structural analogues in such conditions has been extended to seek further well-preserved objects in such conditions. The objectives of the study are partly scientific and partly aimed at the public. A wide range of exceptionally wellpreserved glass, metal and organic materials is found in the archaeological record from sites that have been characterised by arid conditions for many thousands of years. Underground preservation environments include those either continuously open (caves) or sealed but not ‘backfilled’ (tombs). Preservation of materials in such openings provides a useful analogue reference point for considering the operation and evolution of the Yucca Mountain repository.
Radiation Damage in Pyrochlore and Related Compounds
Authors: Lumpkin G.R. , Whittle K.R. , Rios S. , Trachenko K. , Pruneda M. , Harvey E.J. , Redfern S.A.T. , Smith K.L. , Zaluzec N.J.
Published: April 2011

The radiation damage properties of synthetic pyrochlore-defect fluorite compounds containing lanthanides on the A-site and Ti, Zr, Sn, and Hf on the B-site have been studied extensively using Kr ion irradiation. Using statistical analysis, we show that the results can be quantified in terms of the critical temperature for amorphization, structural parameters, classical Pauling electronegativity difference, and defect energies. The best current model is able to predict the critical temperature to within about 80 degrees Kelvin. The model indicates that radiation tolerance is correlated with an increase in the X anion coordinate toward the value characteristic of the defect fluorite topology, a smaller unit cell dimension, and lower defect energies. Our analysis also demonstrates that radiation tolerance is promoted by an increase in the Pauling cation-anion electronegativity difference or, in other words, an increase in the ionicity of the chemical bonds. Of the two possible cation sites in ideal pyrochlore, the B-site cation appears to play the major role in bonding. This result is supported, for a subset of pyrochlore compounds, by ab initio calculations, which reveal a correlation between the Mulliken overlap populations of the B-site cation and the critical temperature.
The Effect of Nearfield Constraints on the Corrosion Behavior of High Burnup Spent Fuel
Authors: Loida Andreas , Kelm Manfred , Kienzler Bernhard , Geckeis Horst , Bauer Andreas
Published: April 2011

The long-term immobilization for individual radioelements released from the waste form “spent fuel” in solid phases upon groundwater contact depends strongly on the (geo)chemical constraints prevailing in the repository. Related experimental studies comprise effects induced by the presence of Fe based container material, and near field materials other than Fe for a rock salt environment. The effect of the presence of an argillaceous host rock containing organic matter and pyrite on fuel alteration was studied in addition. The results have shown that oxidative radio-lysis products were found to be consumed at a significant extent by the metallic Fe and by the argillaceous host rock. Under these conditions a decrease at a factor of ca.100 for both the matrix dissolution rates and the solution concentrations of U and Pu was found. There is mutual support between the matrix dissolution rates, the solution concentrations and the amounts of oxygen encountered during the experiments under various conditions controlled by the presence of near field materials under study.
Mechanisms governing the release of radionuclides from spent nuclear fuel in geological repository: major outcomes of the European Project SFS
Authors: Poinssot Christophe , Ferry Cécile , Grambow Bernd , Kelm Manfred , Spahiu Kastriot , Martinez Aurora , Johnson Lawrence , Cera Esther , Pablo Joan de , Quinones Javier , Wegen Detlef , Lemmens Karel , Mcmenamin Thomas
Published: April 2011

European Commission supported a wide research project entitled “Spent Fuel Stability under repository conditions” (SFS) within the 5th FWP, the aim of which was to develop a common understanding of the radionuclides release from spent nuclear fuel in geological disposal and build a RN release model in order to assess the fuel performance. This project achieved by the end of 2004 focuses both on the Instant Release Fraction (IRF) model and the Matrix Alteration Model (MAM).

A new IRF model was developed based on the anticipated performances of the various fuel microstructures (gap, rim, grains boundaries) and the potential diffusion of RN before the canister breaching. However, this model lets the choice to the end-user about the degree of conservativeness to consider.

In addition, fuel alteration has been demonstrated to be linked to the production of radiolytic oxidants by water radiolysis at the fuel interface, the oxidation of the fuel interface by radiolytic oxidants and the subsequent release of uranium under the influence of aqueous ligands. A large set of experimental data was therefore acquired in order (i) to upgrade the current radiolytic kinetic scheme, (ii) to experimentally correlate the fuel alteration rate and the fuel specific alpha activity by performing experiments on alpha doped samples, (iii) to experimentally test the potential inhibitor effect of hydrogen on fuel dissolution. Based on these results, a new MAM was developed, which was also calibrated using the experiments on inactive UO2 samples. This model was finally applied to representative granitic, salt and clayey environment to predict spent fuel long-term fuel performance.
An overview of simple basic equations used in HLW glass dissolution modeling: consequences for long term leaching and element profiles
Authors: Aertsens Marc
Published: April 2011

Over the last decades, several models describing glass dissolution have been published. Starting from the basic equations in their simplest form, the relationships between models are evaluated to address the following questions: 'What is the relationship between their basic assumptions?, What is the resulting long term leach rate? and, Which element profiles do they allow one to predict?' Although not part of it, this paper could complement the European project GLAMOR, where two models describing the dissolution of glass in a water solution, the r(t) and the GM models, are used by several groups to fit the same sets of experimental data. In this paper, other models are considered as well and all models are compared with each other.

From comparison with the Boksay model, which uses the same equations, a simplification is suggested for the GM model concerning the water diffusion in the glass. The use of the numerical code developed to solve part of it, can mostly be avoided by using the analytical solution of the Boksay model.
Size Dependent Enhancement of Spin and Orbital Magnetism in CoRh Nanoparticles
Authors: Muñoz-Navia M. , Dorantes-Dávila J. , Amiens C. , Chaudret B. , Zitoun D. , Casanove M.-J. , Lecante P. , Jaouen N. , Rogalev A. , Respaud M. , Pastor G. M.
Published: April 2011

The magnetism of CoRh nanoparticles (NPs) is investigated experimentally and theoretically. NPs of about 2 nm diameter have been synthesized by decomposition of organometallic precursors in mild conditions of pressure and temperature, under hydrogen atmosphere and in the presence of a polymer matrix. The magnetic properties are determined by SQUID and X-ray magnetic circular dichroism. All the studied CoRh clusters are magnetic with an average spin moment per atom that is significantly larger than the one of macroscopic crystals or alloys with similar concentrations. The experimental results and the comparison with theory suggest that the most likely chemical arrangement is a Rh core with a Co-rich outer shell and some degree of intermixing at the CoRh interface. A detailed analysis of the theoretical results from a local perspective shows that the spin and orbital moments of the Co and Rh atoms at the interface are largely responsible for the enhancement of the magnetization.
On the Physics of Magnetic Anisotropy in Co/Pd Multilayer Thin Films
Authors: Smith Darren , Zhang Shishan , Donner Wolfgang , Chunsheng E , Lee T Randall , Khizroev Sahkrat , Litvinov Dmitri
Published: April 2011

(Co/Pd)N multilayers with Co and Pd layer thicknesses of only a few monolayers exhibit high vertical magnetic anisotropy and have been extensively explored as recording medium candidates for high density magnetic recording applications. In the work reported here, the magnetic properties of (Co/Pd)N multilayers deposited by magnetron sputtering and designed for bit-patterned medium applications are correlated with X-Ray Photoelectron Spectroscopy (XPS) data – an approach commonly used to probe the binding energies and valence band positions. Although the XPS probing depth is limited to ˜2–3 nm, it is sufficient for the evaluation of the 1–2 topmost bilayers in a multilayer stack, and allows us to infer the relevant details of the bandstructure of the entire film. Confirming theoretical predictions, we demonstrate that the degree of d-shell hybridization at Co/Pd interfaces directly correlates with the magnitude of the magnetic anisotropy. Significantly, the highest hybridization of Pd atoms is observed for about one monolayer thick Co layers in the bilayer stack. Variation of the deposition conditions (e.g., deposition pressure) shows a measurable influence on d-electron hybridization, multilayer microstructure, and magnetic anisotropy.
Spin accumulation in ferromagnetic/nonmagnetic devices
Authors: Posth Oliver , Brands Mario , Dumpich Günter
Published: April 2011

We have fabricated ferromagnetic/nonmagnetic (FM/NM) metal heterojunctions for the detection of the spin accumulation effect in different nonmagnetic metals. The polycrystalline heterojunctions are prepared by high resolution electron beam lithography (HR-EBL) and a special oblique evaporation technique. The ferromagnetic (FM) and the nonmagnetic (NM) metal are evaporated on top of each other in a single evaporation process to achieve a clean interface between the two metals. The spin accumulation effect is detected in nonmagnetic copper (Cu) and aluminum (Al), from which we determine the polarization of the interface between the ferromagnetic and nonmagnetic metal.
Diamagnetic Levitation for Passive Tilt Sensors
Authors: Jiao Lihong , Winistöerfer Martin
Published: April 2011

When diamagnetic materials are exposed to an external magnetic field, a weak magnetic field in the opposite direction to the external field is induced and a magnetic force is generated causing diamagnetic materials to be expelled from the external magnetic field. The magnitude of the force increases with increase of the magnitude of diamagnetic susceptibility, χm. In this study, the levitation of graphite in the magnetic field was investigated.
Conservação pós-colheita de goiabas 'Kumagai': efeito do estádio de maturação e da temperatura de armazenamento
Authors: Morgado Cristiane Maria Ascari , Durigan José Fernando , Lopes Valquíria Garcia , Santos Leandra Oliveira
Published: April 2011

Este trabalho teve como objetivo estabelecer a importância do estádio de maturação e do uso da refrigeração na conservação de goiabas 'Kumagai'. Frutos "de vez" e maduros foram armazenados sob condição de ambiente (21ºC e 85%UR) e a 10ºC (85%UR) e avaliados periodicamente quanto à perda de massa fresca, aparência, podridões, coloração da casca, firmeza da polpa e teores de sólidos solúveis, acidez titulável, ácido ascórbico e polifenóis extraíveis totais, assim como da atividade antioxidante total. Goiabas "de vez", a 21ºC e 85% UR, conservaram sua qualidade por seis dias, mas quando a 10ºC e 85% UR, este período de conservação aumentou para 12 dias. Os frutos armazenados maduros conservaram-se por quatro dias sob condição ambiente, o qual foi ampliado com a refrigeração para 9 dias. Goiabas "de vez", armazenadas a 10ºC, apresentaram a maior vida útil, os maiores teores de sólidos solúveis e de acidez titulável. Também apresentaram aumento nos teores de polifenóis extraíveis totais, com aumento na atividade antioxidante total, e nos teores de ácido ascórbico.
Cultivar and Site-Specific Variation Affect Establishment Potential of the Cleomes Roughseed Clammyweed (Polanisia dodecandra) and Spiderflower (Cleome hassleriana)
Authors: Gómez Raboteaux Nadilia N. , Anderson Neil O.
Published: April 2011

Establishment potential is one of the primary components of invasive species risk assessment. Models that predict establishment of potentially invasive ornamental crops often ignore differences among cultivars and the variability in plant response to site-specific factors. The objective of this study was to determine the extent to which differences among cultivars and habitat characteristics affect establishment of 5 cultivars of ornamental cleome. Experiments were conducted to compare germination, survival, and growth of cultivars in cultivated (gardens) and noncultivated (roadsides and prairies) environments and, in prairies, the effects of competition (low, intermediate, and high). In the first experiment, germination, survival, and growth were recorded in gardens, prairies, and roadsides in four locations in Minnesota. In the second experiment, the effects of competition with resident species were studied in five seed lots from three cultivars in three prairie sites. Additionally, a quantitative description of germination and transplantable seedling quality, when grown under greenhouse production standards, was obtained and compared with results from the cultivated and noncultivated outdoor environments. Germination in greenhouse conditions was significantly greater (78%) than in garden, prairies, or roadsides (< 46%). Mortality was greater in noncultivated than in cultivated environments (3% wk−1 and 1.4% wk−1, respectively). Survival was affected by competition, which reduced population establishment. Cultivar differences were most pronounced at seedling emergence, whereas habitat characteristics were more influential at later stages of the life cycle. Germination and plant height were similar among noncultivated environments. Variability in seedling emergence, survival, and growth in response to cultivar, habitat, and competition are important determinants of establishment potential. Among the cultivars studied, the native cleome, roughseed clammyweed, has a greater establishment potential than the nonnative cleome, spiderflower.
Propoxycarbazone-Sodium and Imazapic Effects on Downy Brome (Bromus tectorum) and Newly Seeded Perennial Grasses
Authors: Sbatella Gustavo M. , Wilson Robert G. , Enloe Stephen F. , Hicks Charlie
Published: April 2011

Vigorous stands of perennial grasses can effectively provide long-term control of many invasive plants on rangelands. However, in degraded conditions, successful reestablishment of perennial grasses can be compromised by invasive annual grasses, such as downy brome. Propoxycarbazone-sodium is a selective herbicide currently labeled for downy brome control in small grains, but its potential use on rangelands is unknown. Studies were conducted from 2004 through 2008 at three rangeland sites in Colorado and Nebraska to evaluate downy brome control and perennial grass injury with propoxycarbazone-sodium and imazapic. Propoxycarbazone-sodium provided satisfactory downy brome control with grass injury equal to or less than imazapic when rainfall followed the fall application. A second set of studies was conducted from 2007 to 2008 at Lingle, WY, and Scottsbluff, NE, to determine the plant-back interval and postemergence application response of seven perennial grass species to propoxycarbazone-sodium and imazapic. Grass tolerance to both herbicides was good when applied 90 and 120 d before planting (DBP). However, grass injury increased as plant-back interval decreased. The greatest impact on plant biomass was observed from herbicide applied at planting or after planting. Crested and intermediate wheatgrass (Agropyron cristatumandThinopyrum intermedium) biomass production was not affected when herbicides were applied 90 or 120 DBP. Western wheatgrass (Pascopyrum smithii) and Russian wildrye (Psathyrostachys juncea) showed tolerance to imazapic applied before planting. Smooth brome (Bromus inermis), sheep fescue (Festuca ovina), and orchardgrass (Dactylis glomerata) showed the least amount of tolerance to propoxycarbazone-sodium and imazapic.
Relationships of Native Desert Plants with Red Brome (Bromus rubens): Toward Identifying Invasion-Reducing Species
Authors: Abella Scott R. , Craig Donovan J. , Chiquoine Lindsay P. , Prengaman Kathryn A. , Schmid Sarah M. , Embrey Teague M.
Published: April 2011

The interactions between native and exotic species occur on a continuum from facilitative to competitive. A growing thrust in invasive species science is differentiating where particular native species occur along this continuum, with practical implications for identifying species that might reduce the invasibility of ecosystems. We used a greenhouse experiment to develop a competitive hierarchy of 27 native species with red brome, an invasive annual grass in the arid lands of the southwestern United States, and a field study to assess in situ responses of brome to native perennial species in the Mojave Desert. Native species most competitive with brome in the competition experiment included the annuals Esteve's pincushion and western fiddleneck and the perennials eastern Mojave buckwheat, sweetbush, and brittlebush, which reduced brome biomass to 49 to 70% of its grown-alone amount. There was no clear difference in competitive abilities with brome between annual and perennial natives, and competiveness was not strongly correlated (r= 0.15) with the biomass of the native species. In the field, sweetbush and brittlebush supported among the least cover of brome, suggesting congruence of the strong early competitive abilities of these species with in situ patterns of brome distribution. At the other extreme, brome attained its highest average cover (19%) below littleleaf ratany, significantly greater than all but 3 of the 16 species evaluated. Cover by brome was only weakly related (r= 0.19) to the area of the perennial canopy, suggesting that factors other than the sizes of perennial plants were linked to differences in brome cover among species. Results suggest that (1) interactions with brome differ substantially among native species, (2) these interactions are not as closely linked to biomass production as in more temperate regions, and (3) there is potential for identifying native species that can reduce invasion of desert ecosystems.
Control of Orange Hawkweed (Hieracium aurantiacum) in Southern Alaska
Authors: Seefeldt Steven S. , Conn Jeffery S.
Published: April 2011

Orange hawkweed is a perennial European plant that has colonized roadsides and grasslands in south-central and southeast Alaska. This plant is forming near-monotypic stands, reducing plant diversity, and decreasing pasture productivity. A replicated greenhouse study was conducted in 2006 and repeated in 2007 to determine the efficacy of six herbicides (aminopyralid, clopyralid, picloram, picloram + chlorsulfuron, picloram + metsulfuron, and triclopyr) for orange hawkweed control. Based on results of the greenhouse trials, replicated field studies were conducted at two sites each year in 2007 and 2008 with three rates each of aminopyralid and clopyralid to determine efficacy of orange hawkweed control and impacts on nontarget native vegetation. In the field, only aminopyralid at 105 g ae ha−1 (0.1 lb ae ac−1) and clopyralid at 420 g ae ha−1 controlled orange hawkweed consistently, with peak injury observed 1 yr after treatment. Control with clopyralid was slightly less than that provided by aminopyralid at all observation times, except at Homer, AK, in 2007, where there was a near-monotypic stand of orange hawkweed, and clopyralid did not remove all orange hawkweed plants. Aminopyralid controlled clover (Trifolium spp.), seacoast angelica (Angelica lucida), arctic daisy (Chrysanthemum arcticum), common hempnettle (Galeopsis tetrahit), and willow (Salix spp.) in the treated areas. Other plant species, such as grasses and some annual forbs, recovered or increased following control of the hawkweed. Clopyralid had less impact on nontarget species with most recovering the year after treatment. In a pasture system, where grasses are preferred to forbs and shrubs, aminopyralid has an advantage because it controls a broader array of forbs compared with clopyralid. In natural areas, where the desire to retain biodiversity and the aesthetics of multiple forb species mixed with grasses and willows is preferred, clopyralid will leave greater species diversity than aminopyralid.
Bushkiller (Cayratia japonica) Response to Selected Herbicides
Authors: West Amanda M. , Richardson Robert J. , Gardner Andrew P. , Hoyle Steve T.
Published: April 2011

Bushkiller, an aggressive perennial vine native to Southeast Asia, has invaded several sites in Alabama, North Carolina, Texas, Louisiana, and Mississippi. Bushkiller has only recently been discovered in North Carolina. The potential economic and environmental consequences associated with established exotic invasive perennial vines and the lack of published control measures for bushkiller prompted research to be conducted at North Carolina State University that may be used in an early-detection rapid-response program. Field and greenhouse studies were conducted to determine bushkiller response to selected foliar-applied herbicides. Field study 1 evaluated efficacy of glyphosate, triclopyr, triclopyr plus 2,4-D, triclopyr plus aminopyralid, and triclopyr plus glyphosate applied postemergence to bushkiller. No control was evident from any treatment at 10 mo after application. In a separate experiment, aminocyclopyrachlor, imazapyr, metsulfuron, sulfometuron, and sulfometuron plus metsulfuron were applied postemergence to bushkiller. Control with aminocyclopyrachlor, imazapyr, sulfometuron, and sulfometuron plus metsulfuron was 88 to 99% at 10 mo after application. Each treatment was also applied to bushkiller in a greenhouse trial. Aminocyclopyrachlor and triclopyr-containing treatments generally resulted in the greatest control, lowest dry weights, and shortest vine lengths among the treatments. These results indicate that several herbicides may be employed initially in an early-detection, rapid-response program for bushkiller. Additional research is needed to determine how effective these herbicides would be in multiple-season treatments that may be required at well established bushkiller infestation sites.
Clinical Evidence of Beneficial Effects of Omega-3 Fatty Acids in Allergy and Asthma
Authors: Estela Del Rio Navarro Blanca , Roberto Pietropaolo Cienfuegos Dino , Antonio Gongora Melendez Marco
Published: April 2011

The prevalence of allergic diseases has importantly increased in the last years in some parts of the
world. The related causes are poorly known. However, it is thought to be associated to a complex interaction of
genetic and environmental factors. There’s some epidemiological evidence that the reduction in omega-3 long
chain polyunsaturated fatty acids (ω-3 LC-PUFAS) intakes with the increased allergy prevalence. At this time,
there’s not enough evidence to recommend ω-3 LC-PUFAS supplementation, neither in the pregnant mother, nor
in the breastfeeding mother, in order to prevent allergic disease development in high risk population (primary
prevention). However, current studies are too heterogeneous and consider only ω-3 LC-PUFAS intake at lower
doses. We need to develop more studies with high dose of ω-3 LC-PUFAS to elucidate that issue. Similarly, there
are no conclusive data about the prevention of allergy development in high risk infants feeding with ω-3 LCPUFAS
supplementation. ω-3 LC-PUFAS consumption may reduce the use of anti-inflammatory drugs in the
treatment of asthma, probably because both of them exert their effects, almost in part, through the same molecular
actions. There may be a role of lipid mediators derived from ω-3 LC-PUFAS metabolism (lipoxins and resolvins)
in the resolution of allergic asthma inflammation. Hence, synergy between ω-3 LC-PUFAS and drugs may take
place and represent an adjunctive therapy in asthma (secondary prevention). Placebo-controlled studies with highquality
methodology design are required so as to draw better conclusions, especially with the employment of ω-3
LC-PUFAS at high doses (2-4 grams per day).
The Impact of Perceived Stress, Social Support, and Home-Based Physical Activity on Mental Health among Older Adults
Authors: Kwag Kyung Hwa , Martin Peter , Russell Daniel , Franke Warren , Kohut Marian
Published: April 2011

This study investigated how perceived stress, social support, and home-based physical activity affected older adults' fatigue, loneliness, and depression. We also explored whether social support and physical activity mediated the relationships between stress and mental health problems. The data of 163 older participants were analyzed in this study. Structural equation modeling using LISREL 8.71 was performed to assess the effects of stress, support, and physical activity on mental health. The findings indicate that perceived stress predicted higher levels of depression, social support predicted lower levels of loneliness and fatigue, and physical activity predicted lower levels of fatigue among older adults. Social support and physical activity mediated the relationships between stress and mental health, except depression. In conclusion, the relative impacts of perceived stress, social support, and physical activity on types of mental health (e.g., fatigue, loneliness, and depression) were different. Furthermore, stress had direct and indirect effects on each construct of mental health (e.g., fatigue, loneliness, and depression).
Leafhoppers and cixiids in phytoplasma-infected carrot fields: Species composition and potential phytoplasma vectors
Authors: Drobnjakovic Tanja , Peric Pantelija , Marcic Dejan , Picciau Luca , Alma Alberto , Mitrovic Jelena , Duduk Bojan , Bertaccini Assunta
Published: April 2011

The first molecular analysis of samples collected in southern Backa (Serbia)
confirmed the presence of aster yellows (16SrI) and stolbur phytoplasmas
(16SrXII) in insects belonging to the family Cicadellidae, as well as in
carrot plants where the insects were collected. A correct identification of
the phytoplasmas and their vectors is essential to arrange effective control
strategies to prevent diseases associated with phytoplasmas from spreading to
carrots and other vegetable crops. In order to enhance knowledge about insect
vectors of aster yellows and stolbur phytoplasmas in Serbia, Cicadellidae and
Cixiidae (Homoptera Auchenorrhyncha), the most common vectors of these
phytoplasmas, were monitored in southern Backa during 2008. Adults leaf- and
planthoppers were collected and identified at species level using standard
entomological methods, and tested for phytoplasma presence by means of
PCR/RFLP. A total of 13 insect species of Cicadellidae were identified, as
follows: a) three species of the subfamily Agallinae: Anaceratagallia ribauti
(Ossiannilsson), Anaceratagallia venosa (Fourcroy), and Anaceratagallia
laevis (Ribaut); b) seven species of the subfamily Deltocephalinae:
Psammotettix confinis (Dahlbom), Psammotettix striatus (Linnaues)
Psammottettix alienus (Dahlbom), Macrosteles sexnotatus (Fall?n), Ophiola
decumana (Kontkanen), Errastunus ocellaris Fall?n, and Scaphoideus titanus
Ball; c) three species of the subfamily Typhlocibinae: Eupteryx atropunctata
(Goeze), Eupteryx mellissae Curtis, Zyginidia pullula (Boheman). Female
specimens of the genus Euscelis (Deltocephalinae) were also collected, as
well as one species of Reptalus quinquecostatus (Dufour) of the family
Cixiidae. Stolbur phytoplasmas were detected in A. laevis, A. ribauti, A.
venosa, P. striatus, P. confinis and P. alienus. The species: A. laevis, O.
decumana, and P. confinis were AY-infected (subgroup 16SrI-A), while subgroup
16SrI-C was found only in one specimen of P. confinis. Since some aster
yellows- and stolbur-infected species of the genera Psammotettix and
Anaceratagallia (especially P. confinis and A. laevis) were regularly and
commonly found in the infected carrot fields during the whole vegetative
period, they could play a significant role in transmitting and spreading
these pathogens in natural environment.
In vitro sensitivity of Fusarium graminearum (Schwabe) to difenoconazole, prothioconazole and thiophanate-methyl
Authors: Rekanovic Emil , Mihajlovic Milica , Potocnik Ivana
Published: April 2011

A survey of in vitro sensitivity of eight isolates of the Fusarium
graminearum to the fungicides difenoconazole, prothioconazole and
thiophanate-methyl, was undertaken. The isolates were isolated from infected
wheat heads collected from 8 different localities in Serbia over the period
2005-2006. Among the tested isolates ZE (RF=11.34), RU (RF=5.98) and AR
(RF=5.08) isolates showed moderate resistance to difenoconazole. The EC50
values of this isolates were 19.16, 10.09, and 8.59 mg l-1, respectively. The
isolates ZE (RF=5.38) and RU (RF=4.43) also showed the moderate resistance to
prothoconazole. The EC50 values were 9.69 and 7.97 mg l-1, respectively. All
the isolates tested were the least sensitive to thiophanate-methyl. The EC50
values were in range of 12.1 to 64.03 mg l-1. The highest resistance factor
was found for the isolates ZE (RF=5.29).
Ablation of PI3K p110-α Prevents High-Fat Diet–Induced Liver Steatosis
Authors: Chattopadhyay Mohar , Selinger Elzbieta S. , Ballou Lisa M. , Lin Richard Z.
Published: April 2011

OBJECTIVE

To determine whether the phosphoinositide 3-kinase (PI3K) catalytic subunits p110-α and p110-β play a role in liver steatosis induced by a high-fat diet (HFD).

RESEARCH DESIGN AND METHODS

Liver-specific p110-α and p110-β knockout mice and control animals for each group were fed an HFD or normal chow for 8 weeks. Biochemical assays and quantitative real-time PCR were used to measure triglyceride, expression of lipogenic and gluconeogenic genes, and activity of protein kinases downstream of PI3K in liver lysates. Fatty acid uptake and incorporation into triglycerides were assessed in isolated hepatocytes.

RESULTS

Hepatic triglyceride levels in HFD-fed p110-α−/− mice were 84 ± 3% lower than in p110-α+/+ mice, whereas the loss of p110-β did not significantly alter liver lipid accumulation. p110-α−/− livers also showed a reduction in atypical protein kinase C activity and decreased mRNA and protein expression of several lipogenic genes. Hepatocytes isolated from p110-α−/− mice exhibited decreased palmitate uptake and reduced fatty acid incorporation into triglycerides as compared with p110-α+/+ cells, and hepatic expression of liver fatty acid binding protein was lower in p110-α−/− mice fed the HFD as compared with controls. Ablation of neither p110-α nor p110-β ameliorated glucose intolerance induced by the HFD, and genes involved in gluconeogenesis were upregulated in the liver of both knockout animals.

CONCLUSIONS

PI3K p110-α, and not p110-β, promotes liver steatosis in mice fed an HFD. p110-α might exert this effect in part through activation of atypical protein kinase C, upregulation of lipogenesis, and increased uptake of fatty acids.
Syncretism without underspecification: The role of leading forms
Authors: Müller Gereon
Published: April 2011

The main goal of this article is to outline a new approach to syncretism in optimality theory, one that does not rely on the concept of underspecification taken over from grammatical theories which do not recognize constraint ranking and constraint violability. The analysis is based on a concept of morphological exponents as leading forms. Instances of syncretism can be traced back to the selection of unfaithful leading forms as a last resort to avoid paradigmatic gaps: The minimally unfaithful leading form exponent spreads to an empty paradigm cell. Three well-studied empirical domains figure in the analysis: (i) determiner inflection in German ( Bierwisch 1967 , Wiese 1999 ), (ii) Italian object clitics ( Grimshaw 2001 ), and (iii) animacy effects with noun inflection in Russian ( Wunderlich 2004 ).
« Né pour voir »
Authors: Lacoste Jean
Published: April 2011

Résumé Peu nombreuses, mais significatives, sont les références à Goethe dans l’œuvre de Jean Starobinski, qui semble accorder à ce dernier une « autorité » particulière, en particulier dans la confrontation avec Rousseau. L’auteur de Werther n’incarne-t-il pas d’abord le spleen surmonté et maîtrisé ? Mais plus largement Goethe écrit à un moment historique décisif, où les sciences modernes, qui « désenchantent » le monde, divorcent de la littérature, à qui échoit désormais la mission de rendre compte de « l’expérience intérieure ». C’est dans ce cadre que Starobinski élabore son « histoire sémantique » des notions médicales comme la mélancolie. Ce faisant, il propose aussi une autre image de Goethe : non plus le porte-parole de la raison classique, mais le poète qui, dans Faust , fait sa part à l’ombre.
El lenguaje de la ciencia
Authors: Lorenzano César
Published: April 2011

En el comienzo de la filosofía de la ciencia, el neopositivismo propuso que el fisicalismo fuera el lenguaje básico, común a todas las disciplinas científicas. Sabemos de sus dificultades, y de sus fracasos.
En el presente artículo me propongo analizar el lenguaje empleado en un caso de investigación aplicada –y asimismo básica– perteneciente al campo de la clínica médica, a los efectos de sopesar la posibilidad de que exista un lenguaje único de la ciencia, o si éste es un sueño inalcanzable.
Aunque el análisis sea estructural, el caso posibilita de una manera natural la reconstrucción de la teoría clínica médica mediante la caracterización de sus ejemplares, prescindiendo, por lo tanto, de modelos matemáticos.
Al finalizar el recorrido, nos reencontramos con el viejo sueño neopositivista, al proponer que el lenguaje básico de la ciencia –en realidad, el lenguaje más apropiado para la reconstrucción de las teorías científicas– es de índole fisicalista y nominalista.
¿Es Priscilla, el positrón atrapado, un individuo? La física cuántica, el uso de nombres y la individuación
Authors: Krause Décio
Published: April 2011

El Premio Nobel Hans Dehmelt aprisionó un positron, que fue llamado “Priscilla”. Dehmelt dijo que no podemos dudar de la identidad de Priscilla. Eso nos coloca un problema filosófico, puesto que aprendimos con la mecánica cuántica (en sus principales interpretaciones) que los objetos cuánticos no deberían tener individualidad. En este artículo, discutimos las cuestiones de nombrar los quanta y las cuestiones de la individuación. Conclúyenos que, a pesar de que Dehmelt nombró algo, ese algo no es un individuo.
Narraciones españolas del fin del mundo. I. Las novelas laicas
Authors: Jaureguízar Agustín
Published: April 2011

Las novelas del fin de los tiempos son frecuentes en las literaturas de muchos países, que se han preocupado de darlas a conocer, no así en España. Son narraciones en las que el autor se compromete a enjuiciar a la Humanidad que va a hacer desaparecer. Es lo más común que, partiendo en principio de un progreso sin límites de la civilización, esta idea termine por dar paso a la contraria y surja la gran pregunta: ¿La Humanidad perece por azar o como consecuencia de sus actos? En las dos novelas que reseñamos está llamada a perecer por infortunio, aunque en una se dé el caso excepcional de que el esfuerzo colectivo de la Humanidad entera va a evitar la catástrofe.
Ambulatory Blood Pressure Monitoring in Resistant Hypertension
Authors: Syrseloudis Dimitrios , Andrikou Ioannis , Andrikou Eirini , Dimitriadis Kyriakos , Stefanadis Christodoulos
Published: April 2011

ABPM constitutes a valuable tool in the diagnosis of RH. The identification of white coat RH and masked hypertension (which may fulfill or not the definition of RH) is of great importance in the clinical management of such patients. Moreover, the various ABPM components such as average BP values, circadian BP variability patterns, and ambulatory BP-derived indices, such as ambulatory arterial stiffness index (AASI), add significantly to the risk stratification of RH. Lastly, ABPM may indicate the need for implementation of specific therapeutic strategies, such as chronotherapy, that is, administration-time dependent therapy, and the evaluation of their efficacy.