Distribution by Scientific Domains

Kinds of Grains

  • barley grain
  • batio3 grain
  • cereal grain
  • columnar grain
  • crystal grain
  • detrital grain
  • dust grain
  • fine grain
  • food grain
  • individual grain
  • large grain
  • maize grain
  • mineral grain
  • organic grain
  • other grain
  • plagioclase grain
  • pollen grain
  • quartz grain
  • rice grain
  • sand grain
  • silicate grain
  • single grain
  • small grain
  • smaller grain
  • spatial grain
  • spherical grain
  • starch grain
  • wheat grain
  • whole grain
  • zno grain

  • Terms modified by Grains

  • grain boundary
  • grain boundary diffusion
  • grain boundary migration
  • grain boundary sliding
  • grain boundary structure
  • grain characteristic
  • grain crop
  • grain density
  • grain disease
  • grain farmer
  • grain filling
  • grain growth
  • grain growth behavior
  • grain growth method
  • grain legume
  • grain microstructure
  • grain morphology
  • grain orientation
  • grain production
  • grain quality
  • grain shape
  • grain size
  • grain size distribution
  • grain sorghum
  • grain structure
  • grain trade
  • grain weight
  • grain yield

  • Selected Abstracts


    ABSTRACT The addition of popped Amaranthus cruentus grain to wheat bread formulation at 10, 15 and 20% levels (flour basis) was carried out to test the effects on sensory and nutritional characteristics of the supplemented bread samples. The addition of popped amaranth grain increased ash, protein and crude fiber content significantly. Zinc content increased by 42.6,74.6%, manganese content by 51.7,90.8%, magnesium content by 75.7,88.0% and calcium content by 57,171% in the supplementation ranges from 10 to 20% of popped amaranth grain. Bread samples supplemented with popped grains had a significantly higher content of squalene in comparison with the control sample (8,12 times higher). Loaf volume of supplemented bread samples decreased from 3.54 to 2.36 mL/g. Also, a significant increase in crumb hardness and lower crumb elasticity was observed. The supplementation contributed to denser crumb structure, more uniform porosity, improved crust color and flavor. It might be concluded that supplementation levels up to 15% (flour basis) were sensorially acceptable. PRACTICAL APPLICATIONS Bread made from refined wheat flour, besides being a good source of energy, is considered to be nutritionally poor. Therefore, the addition of inexpensive staples with superior nutritional quality such as some pulses, cereals or pseudocereals to wheat flour could improve the nutritional quality of wheat products. Amaranth is a pseudocereal that contains high levels of fat, dietary fibers, lysine and minerals, especially calcium and magnesium. The addition of amaranth grain to wheat bread contributes to higher intakes of proteins, fibers, fat and minerals. The usage of popped amaranth grain is advantageous because it excludes the need for grain milling and the necessity for preparative steps before mixing in bakeries. In addition, thermal treatment increases the protein efficiency ratio and gelatinizes starch that affects positively the stability, strength and freshness of the crumb. Popped amaranth grain also contributes to the pleasant taste and overall acceptability of supplemented bread. [source]


    ARCHAEOMETRY, Issue 2 2009
    A. HEIER
    Carbonized grains survive for millennia in many archaeological contexts. Their stable structure raises the possibility that they preserve biogenic strontium isotope signatures. This hypothesis was investigated using short-term, laboratory experiments with modern grain immersed in Chalk solution. HCl leaching removed > 95% of secondary alteration from charred grain, and isotope ratios close to the starting value were recovered. This could not be achieved with uncharred grains. HCl leaching of archaeological carbonized grains produced comparable levels of decontamination. Although preliminary, these results suggest that strontium isotope analysis of archaeological carbonized grains from calcareous burial contexts could be used to investigate ancient trade and agriculture. [source]


    JOURNAL OF FOOD SAFETY, Issue 3 2006
    ABSTRACT Ninety random grain samples were collected and analyzed for mycotoxins, and the effect of gamma irradiation on the production of mycotoxins in grains was studied. Aspergillus, Penicillium, Mucor, Rhizopus, Fusarium, Alternaria, Scopulariopsis and Cladosporium were the most common fungal genera isolated from grains. Aspergillus flavus, Aspergillus niger, Aspergillus candidus, Aspergillus ochraceus, Penicillium citrinum, Penicillium expansum, Penicillium citreonigrum, Penicillium purpurogenum, Penicillium griseofulvum and Penicillium verrucosumwere the most common Aspergillus and Penicillium species in grains. Out of 120 Aspergillus and Penicillium isolates, 80 were mycotoxin producers. Analysis of grains revealed the occurrence of aflatoxin B1 ochratoxin A, cycolopiazonic acid and citrinin. Of the 90 samples, 67 were positive for one or more mycotoxin. Irradiation of grains at dose of 2.0 and 4.0 kGy decreased significantly the total fungal counts compared with unirradiated controls. After 100 days of storage at room temperature, the unirradiated grains were contaminated with high concentrations of mycotoxins as compared with irradiated 4.0-kGy samples. Mycotoxin production in grains decreased with increasing irradiation doses and was not detected at 6.0 kGy over 100 days of storage. [source]

    Going Against the Historical Grain: Perspectives on Gendered Occupational Identity and Resistance to the Breakdown of Occupational Segregation in Two Manufacturing Firms

    Anne-marie Greene
    This article discusses a process of restructuring of working practices within two manufacturing firms with respect to its implications for gendered occupational segregation. A contextualized, historically situated analysis is presented, which is cast within debates on the nature of gendered occupational identity, equality initiatives and arenas of power and influence for women and men, within what were traditionally male-dominated organizational contexts. Such an analysis serves to highlight the significance of the new restructuring in sweeping away 150 years of practice and embedded ,ways of doing things' and offers explanations for the actions of contemporary men and women in opposing what were seen by management and the trade union as emancipatory changes. [source]

    Effects of Post-Anthesis Drought and Waterlogging on Accumulation of High-Molecular-Weight Glutenin Subunits and Glutenin Macropolymers Content in Wheat Grain

    D. Jiang
    Abstract Drought and flooding during grain filling have become major constraints to wheat quality and yield. The impacts of water deficits and waterlogging during the grain filling on contents of high-molecular-weight glutenin subunits (HMW-GS) and of glutenin macropolymers (GMP) in grains of the winter wheat cultivar Yumai 34 with high grain protein content (GPC) and Yangmai 9 with low GPC were studied. At maturity, GPC was higher under drought and lower under waterlogging compared to the control, while contents of GMP and HMW-GS were reduced by the two water-stress treatments. The contents of both HMW-GS and GMP were higher in Yumai 34 than in Yangmai 9. A drought event after anthesis increased the accumulation of HMW-GS during the early grain filling stage. By contrast, waterlogging reduced the accumulation of HMW-GS during the whole grain filling phase. At maturity, the HMW-GS and GMP to protein ratios were also depressed under the two water-stress events, while the HMW-GS to GMP ratio was very close between the three treatments in Yumai 34 and much higher under the control than the drought and waterlogging treaments in Yangmai 9. It is concluded that the variation in GMP content with various water-stress treatments is attributed to the changing in accumulation of HMW-GS in the grain. [source]

    Influence of Health and Environmental Information on Hedonic Evaluation of Organic and Conventional Bread

    L.E. Annett
    ABSTRACT:, Grain from paired samples of the hard red spring wheat cultivar "Park" grown on both conventionally and organically managed land was milled and baked into 60% whole wheat bread. Consumers (n= 384) rated their liking of the bread samples on a 9-point hedonic scale before (blind) and after (labeled) receiving information about organic production. Consumers liked organic bread more (P < 0.05) than conventional bread under blind and labeled conditions. Environmental information about organic production did not impact consumer preference changes for organic bread, but health information coupled with sensory evaluation increased liking of organic bread. Ordinary least squares (OLS) and binary response (probit) regression models identified that postsecondary education, income level, frequency of bread consumption, and proenvironmental attitudes played a significant role in preference changes for organic bread. The techniques used in this study demonstrate that a combination of sensory and econometric techniques strengthens the evaluation of consumer food choice. [source]

    Sensory Profiles of Bread Made from Paired Samples of Organic and Conventionally Grown Wheat Grain

    L.E. Annett
    ABSTRACT:, The Canadian hard red spring wheat cultivar "Park" was grown in 2005 in Edmonton, AB, Canada on both conventionally and organically managed land, situated less than 1 km apart. Grains from the paired wheat samples were compared for cereal-grain-quality attributes. For sensory analysis, organically and conventionally produced wheat grains were milled into flour and baked into 60% whole wheat bread. Color, texture, taste, and aroma attributes of bread were compared using the sensory technique of descriptive analysis. Organic grain contained more wholemeal protein than conventional grain (P, 0.05), but both were greater than 14% protein, indicating excellent grain quality for yeast-leavened bread. Mixograph analysis revealed that conventional flour produced stronger bread dough than organic flour (P, 0.05). Visual observation confirmed these findings as conventional flour produced larger bread loaf volume. Fourteen sensory attributes were generated by the descriptive analysis panel. No differences were observed for flavor, aroma, or color attributes (P > 0.05), but the panel perceived the organic bread to be more "dense" in texture (P, 0.05) with smaller air cells in the appearance of the crumb (P, 0.05) than conventional bread. [source]

    Occurrence and Distribution of Microdochium and Fusarium Species Isolated from Durum Wheat in Northern Tunisia and Detection of Mycotoxins in Naturally Infested Grain

    Lobna Gargouri Kammoun
    Abstract An outbreak of Fusarium Head Blight of durum wheat occurred in 2004 being localized in sub-humid and higher semi-arid region of Northern Tunisia. A mycological survey carried out throughout these regions, revealed that 78% of the prospected fields were infested. Results of the morphological and molecular identification, showed that the most common species isolated from diseased wheat spikes was Microdochium nivale var. nivale (63.5%), followed by Fusarium culmorum (26%), F. pseudograminearum (9%) and F. avenaceum (1.5%). To evaluate mycotoxin content of naturally infected grain, the amounts of trichothecene mycotoxin deoxynivalenol (DON) in harvested grain from 45 fields were quantified by RIDASCREEN DON Enzyme Immunoassay Kit (ELISA). This study showed that the infection levels in freshly harvested grain were very low and the maximum deoxynivalenol (DON) level of the positive samples was 53 ppb. This is the first report on the natural occurrence of DON in naturally infected wheat grain sampled from Northern Tunisia. [source]

    Yield response of wheat and barley to inoculation of plant growth promoting rhizobacteria at various levels of nitrogen fertilization

    Ali Ozturk
    Abstract The yield response of a wheat (Kirik) and a barley (Tokak 157/37) cultivar to inoculation with Azospirillum brasilense Sp246 and Bacillus sp. OSU-142 was studied in relation to three levels of N fertilization (0, 40, and 80 kg ha,1) under field conditions in Erzurum, Turkey, in 1999 and 2000. Seed inoculation with A. brasilense Sp246 significantly affected yield and yield components, both in wheat and barley. On average of years and N doses, inoculation with A. brasilense Sp246 increased spike number per m2, grain number per spike, grain yield, and crude protein content by 7.2, 5.9, 14.7, and 4.1,% in wheat and by 6.6, 8.1, 17.5, and 5.1,% in barley, respectively, as compared to control. Inoculation with Bacillus sp. OSU-142 significantly increased kernel number per spike in wheat, but no significant effect was determined in the other characteristics. Grain yields and yield components were also higher at all levels of nitrogen fertilizer in the inoculated plots as compared to the control. However, these increases diminished at high fertilizer levels. These results suggest that application of the growth promoting bacteria A. brasilense Sp246 may have the potential to be used as a biofertilizer for spring wheat and barley cultivation in organic and low-N input agriculture. No translation. [source]

    Getting Behind the Grain: The Politics of Genetic Modification on the Canadian Prairies

    ANTIPODE, Issue 2 2009
    Emily Eaton
    Abstract:, In 2001 a coalition of actors including farm, consumer, health, environmental and industry organizations announced its opposition to Monsanto's attempts to commercialize GM wheat in Canada. Although this coalition consisted mostly of rural and agricultural groups, the three arguments that came to dominate the discourse advanced by the coalition seem, at first glance, to characterize a politics of consumption. These three arguments revolve around market acceptance, environmental risk, and the lack of democratic and transparent process in biotech regulation and policy. This paper argues that producer interests were not displaced by, but rather articulated alongside and through consumer-driven discourses. In fact, farmers used claims about the supremacy of the consumer and impending environmental change to advance their vulnerable political and economic positions as producers of food. [source]

    Parrots Take it with a Grain of Salt: Available Sodium Content May Drive Collpa (Clay Lick) Selection in Southeastern Peru

    BIOTROPICA, Issue 3 2009
    Luke L. Powell
    ABSTRACT Soils from 18 parrot collpas (,clay licks') in southeastern Peru averaged four times more available sodium than uneaten control soils. Collpa soils contained marginally more clay than control sites and clay content was uncorrelated with available sodium content. Parrots may select and ingest soils based on available sodium content. RESUMEN Suelos de 18 colpas de loros del sureste del Perú promediaron cuatro veces más sodio disponible que suelos control no consumidos. Suelos de colpas fueron un poco más arcillosos que los suelos control; además el contenido de arcilla no presentó correlación con el contenido de sodio disponible. Concluimos que la selección y consumo de suelos por loros se basa en el contenido de sodio disponible. [source]

    Assessing Producer Stated Preferences for Identity Preservation in the Canadian Grain Handling and Transportation System

    Darren Barber
    Agricultural biotechnology will create a new set of challenges for the bulk grain handling and transportation system (GHTS) in Canada. The implementation of a credible grain identity preservation system to segregate genetically modified (GM) from non-GM grain remains an important and unresolved issue for the industry. Furthermore, the attitude of producers toward the design of an identity preserved grain supply chain is not well understood. Using a 2003 survey of Saskatchewan grain farmers developed by the authors, we employ conjoint analysis to evaluate producer attitudes and trade-offs among four hypothetical grain handling systems. The results indicate that farmers in the region will require significant economic incentives to adopt on-farm segregation methods when compared to methods that segregate grain at the elevator level. Les biotechnologies agricoles vont engendrer de nouvelles préoccupations pour le système de manutention et de transport du grain (SMTG) en vrac au Canada. La mise en uvre d'un système de ségrégation des céréales génétiquement modifiées (GM) et non génétiquement modifiées (NGM) demeure un problème important non résolu pour l'industrie. De plus, l'attitude des producteurs envers la mise en place d'une chaîne d'approvisionnement de céréales à identité préservée n'est pas bien comprise. À l'aide d'un sondage que nous avons mis au point et effectué auprès des producteurs de céréales de la Saskatchewan, nous utilisons l'analyse conjointe pour évaluer l'attitude et les options des producteurs par rapport à quatre systèmes hypothétiques de manutention des céréales. Les résultats ont montré que les producteurs de la province exigeront d'importants stimulants économiques pour adopter des méthodes de ségrégation à la ferme comparativement aux méthodes de ségrégation en vigueur aux silos à céréales. [source]

    From Single Grains to Texture

    Kun Yan
    Abstract Structural materials, such as metals, ceramics, and their composites are most often polycrystalline. The nature, morphology, and composition of their microstructure determine in large measure the mechanical properties of the final product, and the art to design novel materials is to find particular arrangements which make them harder, more shock absorbing, heat resistant, or self-recovering upon damage and aging. The understanding of the basic processes and their interplay in a polycrystalline structure are most important for improved simulation of plastic deformation and to predict their thermo-mechanical behavior. [source]

    Experimental Determination of Fully-Coupled Kinematical and Thermal Fields at the Scale of Grains Under Cyclic Loading

    Laurence Bodelot
    An experimental setup has been developed to measure fully-coupled kinematic and thermal fields at a very fine resolution matching the microstructure size of a heat-treated austenitic stainless steel. In this study, this setup is used in order to investigate the heterogeneous behavior of a polycrystalline material under cyclic loading, as far as the local strain and temperature data are concerned. [source]

    Fabrics, facies control and diagenesis of lacustrine ooids and associated grains from the Upper Triassic, southwest England

    GEOLOGICAL JOURNAL, Issue 1 2002
    P. G. Milroy
    Abstract Petrographic analysis of ooids from the Upper Triassic (Mercia Mudstone Group) of southwest England provides an opportunity to assess in detail the origins, transport pathways and diagenesis of an ancient oolite. The Clevedon Oolite is dolomitized and contains a variety of dissolved ooids (oomoulds) and associated grains. The oomoulds occur in well-sorted, planar and cross-stratified grainstones, packstones, sandstones and conglomerates associated with shoreface, intershoal, foreshore, beachrock and littoral strandplain deposits. The ooids grew in suspension in the shoreface zone and developed a radial aragonite microstructure. The ooids grew to 0.80 mm in diameter, after which they fractured or ceased growing. Broken grains deposited on or near mobile shoals were rapidly recoated, while other grains, deposited in less agitated, intershoal and lower foreshore areas, were micritized or microbially bound into grapestone aggregates. Locally peloids, intraclasts, quartz grains and micritized grains from intershoal areas supplied nuclei for ooids on nearby shoals. Grains deposited in foreshore areas were rapidly cemented into beachrock and reworked into conglomerates. Soon after deposition, the ooids were subjected to widespread aragonite dissolution followed by dolomitization. The lack of pre-dolomitization calcite, together with the abundance of early (pre-compaction) dolospar cements and fabric-selective dolomitization of micritic fabrics, suggest aragonite dissolution by dolomitizing fluids. Copyright © 2002 John Wiley & Sons, Ltd. [source]

    Registered Deposition of Nanoscale Ferroelectric Grains by Template-Controlled Growth,

    ADVANCED MATERIALS, Issue 11 2005
    S. Clemens
    Regular patterns of ferroelectric PbTiO3 nanostructures (see Figure) with lateral dimensions down to 30,60,nm have been grown onto platinized Si substrates by chemical solution deposition. The high registration of the grains is achieved by "top,down"-generated templates of TiO2 dots as seeds for their deposition. Ferroelectricity was verified by piezoresponse force microscopy. [source]

    Heat Shock Protein in Developing Grains in Relation to Thermotolerance for Grain Growth in Wheat

    P. Sharma-Natu
    Abstract Wheat (Triticum aestivum L.) cvs DL 153-2 and HD 2285 (relatively tolerant), HD 2329 and WH 542 (relatively susceptible), were grown under normal (27 November) and late (28 December) sown conditions. In another experiment, these cultivars were grown under normal sowing and at anthesis stage, they were transferred to control (C) and heated (H) open top chambers (OTCs). Under late sowing, wheat cultivars were exposed to a mean maximum temperature of up to 3.6 °C higher than normal sowing and in H-OTCs, mean maximum temperature was 3.2 °C higher than C-OTCs during grain growth period. Heat susceptibility index (S) for grain growth and grain yield was determined at maturity in both the experiments. The level of heat shock protein (HSP 18) in the developing grains was determined in C- and H-OTC grown plants and in normal and late sown plants by Western blot analysis. The moderately high temperature exposure increased the accumulation of HSP 18 in the developing grains. The relatively tolerant cultivars, as also revealed from S, showed a greater increase in HSP 18 compared with susceptible types in response to moderate heat stress. An association of HSP 18 with thermotolerance for grain growth in wheat was indicated. [source]

    Sensory Profiles of Bread Made from Paired Samples of Organic and Conventionally Grown Wheat Grain

    L.E. Annett
    ABSTRACT:, The Canadian hard red spring wheat cultivar "Park" was grown in 2005 in Edmonton, AB, Canada on both conventionally and organically managed land, situated less than 1 km apart. Grains from the paired wheat samples were compared for cereal-grain-quality attributes. For sensory analysis, organically and conventionally produced wheat grains were milled into flour and baked into 60% whole wheat bread. Color, texture, taste, and aroma attributes of bread were compared using the sensory technique of descriptive analysis. Organic grain contained more wholemeal protein than conventional grain (P, 0.05), but both were greater than 14% protein, indicating excellent grain quality for yeast-leavened bread. Mixograph analysis revealed that conventional flour produced stronger bread dough than organic flour (P, 0.05). Visual observation confirmed these findings as conventional flour produced larger bread loaf volume. Fourteen sensory attributes were generated by the descriptive analysis panel. No differences were observed for flavor, aroma, or color attributes (P > 0.05), but the panel perceived the organic bread to be more "dense" in texture (P, 0.05) with smaller air cells in the appearance of the crumb (P, 0.05) than conventional bread. [source]

    Effect of Magnesium Oxide Addition on Surface Roughening of Alumina Grains in Anorthite Liquid

    Mi Jin Kim
    Alumina sintered with 5 wt% anorthite at 1620°C for 48 h has grains with flat boundaries and a size distribution representing abnormal grain growth. TEM observations of the grain triple junctions show flat grain surfaces, some of which are the (0001), ([Onemacr]012), and (1[Onemacr]01) planes. HRTEM observations confirm these surfaces to be atomically flat and hence singular. When sintered further after embedding in MgO powder, the {0001} and { 01[Onemacr]2} planes remain flat, but curved surface segments also appear. These curved surface segments are confirmed to be atomically rough by HRTEM. They are connected to the flat segments with discontinuously changing slopes. Thus, when MgO is added, the singular and rough surface phases coexist. [source]

    Effect of Twin-Plane Reentrant Edge on the Coarsening Behavior of Barium Titanate Grains

    Ho-Yong Lee
    When BaTiO3 ceramics were sintered at relatively low temperatures (,1250°C), the grains with reentrant edges caused by a (111) double twin grew exclusively. As a result, a microstructure with a bimodal grain-size distribution composed of platelike large grains and fine matrix grains was obtained. In contrast, at the usual sintering temperature between 1250° and 1350°C, grains containing a (111) double twin did not exhibit any growth advantage. In this case, a coarse and uniform microstructure was obtained. When this coarse-grained specimen was further heat-treated at 1365°C, the grains possessing a double twin were observed to grow exclusively again. The results were explained in terms of a coarsening process controlled by two-dimensional nucleation. [source]

    Microstructure Development in Unsupported Thin Films

    Brian P. Gorman
    To better understand the role of the substrate in the microstructural evolution of thin films, unsupported nanocrystalline yttrium-stabilized zirconia (ZrO2:16%Y or YSZ) films were examined as a function of temperature and annealing time. Grain growth, texturing, and pinhole formation were measured using transmission electron microscopy (TEM) and electron diffraction. Films were produced and subsequently annealed on metallic grids using a previously developed technique that results in near full density films at low annealing temperatures. Microstructural evolution in these films was unique compared with constrained films. Grains were found to spheroidize much more readily, ultimately resulting in the formation of porosity and pinholes. Grain growth was found to stagnate at a size particular to each annealing temperature, presumably due to the effects of Zener pinning. It is proposed that the lack of substrate strain and confinement effects allows for the dominance of surface energetics with respect to microstructural evolution. [source]

    Growth, Survival, and Body Composition of Cage-Cultured Nile Tilapia Oreochromis niloticus Fed Pelleted and Unpelleted Distillers Grains with Solubles in Polyculture with Freshwater Prawn Macrobrachium rosenbergii

    James H. Tidwell
    Nine 1.0-m3 cages were stocked with 200 juvenile (26 ± 0.9 g) tilapia. Cages were suspended in a 0.2-ha pond stocked with juvenile freshwater prawns Macrobrachium rosenbergii at 40,000/ha. Three replicate cages were randomly assigned to each dietary treatment. In one dietary treatment DDGS was fed as an unpelleted loose grain ration (26% protein). In a second dietary treatment fish were fed DDGS that had been steam-pelleted (23% protein). Fish in a third dietary treatment were fed a commercial catfish diet (31% protein) for comparison. After 12 wk, individual weight, individual length, and specific growth rate were significantly higher (P < 0.05) and feed conversion ratio was significantly lower (P < 0.05) for fish fed the commercial catfish diet than for fish fed either unpelleted or pelleted DDGS. Specific growth rate was significantly higher (P < 0.05) for fish fed pelleted DDGS than for fish fed unpelleted DDGS. Survival did not differ significantly (P > 0.05) among treatments (>95%). Although growth was increased in fish fed the commercial diet, their cost of production (<0.66/kg gain) was significantly higher (P < 0.05) than in fish fed unpelleted and pelleted DDGS (<0.26/ kg gain and <0.37/kg gain, respectively). The costs of gain in fish fed unpelleted DDGS was significantly lower (P < 0.05) than in fish fed the pelleted DDGS. Prawn production was 1,449 kg/ha and addition of tilapia in polyculture increased total pond productivity approximately 81 %. These data suggest that DDGS provides economical growth in tilapia when fed as a direct feed and that polyculture of tilapia may improve overall pond efficiency in freshwater prawn production ponds, even at temperate latitudes. [source]

    Pinning energy of domain walls in MnZn ferrite films

    V. H. Calle
    Abstract Mn Zn ferrite films deposited on (100) MgO substrates by rf sputtering technique with different thicknesses , in the range of 30-450 nm were studied. AFM images show grain size increase as film thickness increases. Grains with diameters between L , 70 and 700 nm were observed. The mono and multidomain regime in MnZn ferrite films and their effect on the pinning energy of domain walls are observed via Magneto-optical Kerr Effect, MOKE. At , , 300 nm, the coercive field, Hc, reaches a maximum value of 80 Oe. This result indicates the existence of a multidomain regime associated to a critical grain size, Lc. We used the Jiles-Atherton model (JAM) to discuss the experimental hysteresis loops. The k pinning parameter obtained from JAM shows a maximum value of k /,o = 67 Am2 for grains with Lc , 529 nm. The total energy per unit area E was correlated with k and D. We found a simple phenomenological relationship given by E , kD; where D is the magnetic domain width. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Spectroscopy of Hydrocarbon Grains toward the Galactic Center and Quintuplet Cluster

    J.E. Chiar
    Abstract Our view of the Galactic center (GC) is affected by extinction from both diffuse interstellar medium (ISM) dust and dense molecular clouds along the line of sight. The enormous visual extinction present toward the center of our Galaxy (,31 magnitudes) necessitates a study of the interstellar dust properties as well as an investigation into the distribution of the different dust components. We have built upon the historic spectroscopy of Willner et al. (1979), Butchart et al. (1986), and McFadzean et al. (1989) in order to investigate the distribution of these dust components across the GC field. Specifically, we employ spectroscopy in the 3 ,m region to investigate absorption features at 3.0 ,m and 3.4 ,m in lines of sight toward the GC central cluster and the Quintuplet cluster to the northeast. The 3.4 ,m feature is one of the primary spectral signatures of the organic component of interstellar dust and is, to date, only observed in the cold diffuse interstellar medium. The 3.0 ,m ice feature is carried by dense molecular cloud material, and can therefore be used to loosely trace the distribution of such material across the GC field. By obtaining spectra for multiple sightlines we have been able to deconvolve the diffuse ISM and dense molecular cloud components. Our study shows that differences exist in the spectra of relatively nearby lines of sight in the Galactic center central cluster. The depth of the 3.0 ,m water-ice feature varies by a factor of almost 5 across a 2 parsec (in projection) region, perhaps re.ecting the clumpy nature of the dense clouds. In addition, we found that the 3.4 ,m hydrocarbon feature varies in depth across the areas studied toward the central cluster, whereas the depth is relatively constant toward the Quintuplet cluster. This is likely a reflection of the distribution of extinction from the foreground diffuse ISM. Our ground-based and space-based spectroscopy reveals differences in absorption features in the 3 and 6 ,m regions between sightlines toward the GC central cluster and those toward the Quintuplet cluster. While the 3 ,m spectra of both regions show a broad absorption feature blueward of the 3.4 ,m absorption, only the Quintuplet spectra show a distinct absorption feature at 3.28 ,m. This feature is indicative of the presence of polycyclic aromatic hydrocarbons (PAHs) along the line of sight. The Quintuplet-proper sources have 6 ,m spectra that are markedly different than that of GC IRS 7 in the central cluster, and instead strongly resemble the spectra seen toward dusty late-type carbon-class (WC)Wolf-Rayet stars. This is the first hint of some spectroscopic similarity between the Quintuplet sources and dusty WC stars. [source]

    Mapping the Conservation Landscape

    Kent H. Redford
    To begin this process and to help build understanding and collaboration, we provide a conceptual map of 21 approaches currently being implemented by 13 conservation organizations. We examined each of these approaches according to (1) the nature of the conservation target,the object(s) of the conservation action; ( 2 ) whether the question addressed is where conservation should be done or how conservation should be done; ( 3 ) the scale ( both grain and extent ) of the approach; and (4 ) the principles that underlie the approach. These questions provide a good way of distinguishing between most of the approaches and reveal that there is less competition between them than is assumed. We conclude that only with explicit understanding can the conservation community and its supporters critically compare approaches and come to a consensus about a set of metrics for measuring and achieving global conservation. Resumen: Para que una colaboración bien fundamentada pueda llevarse a cabo, debe haber un proceso de entendimiento de los distintos enfoques utilizadas por diferentes organizaciones de conservación para preservar la biodiversidad. Para iniciar este proceso y ayudar a fomentar el conocimiento y la colaboración, proveemos un mapa conceptual de 21 enfoques utilizados actualmente por 13 organizaciones conservacionistas. Examinamos cada uno de estos enfoques según (1) la naturaleza del objetivo de conservación,el ( los ) objetos( s ) de las actividades de conservación; ( 2 ) la naturaleza de la pregunta a contestar, ya sea "dónde se debe llevar a cabo la conservación" o "cómo se debe llevar a cabo la conservación"; ( 3 ) la escala ( tanto a nivel de detalle como extensión ) del enfoque; (4 ) los principios que constituyen el fundamento del enfoque. Estas preguntas proveen una buena manera de diferenciar la mayoría de las metodologías y muestran que hay menos competencia entre los enfoques de lo que se cree. Concluimos que la comunidad conservacionista y sus seguidores solo podrán comparar los diversos enfoques de manera criteriosa si tienen un entendimiento explícito de los mismos, y de esa manera, podrá desarrollar, por consenso, una serie de variables para medir y lograr la conservación a nivel global. [source]

    The Argument from the finer-grained content of colour experiences A redefinition of its role within the debate between McDowell and non-conceptual theorists

    DIALECTICA, Issue 1 2003
    Annalisa COLIVA
    In this paper I address the question of whether the fact that our colour experiences have a finer-grained content than our ordinary colour concepts allow us to represent should be taken as a threat to theories of the conceptual content of experience. In particular, I consider and criticise McDowell's response to that argument and propose a possible development of it. As a consequence, I claim that the role of the argument from the finer-grained content of experience has to be redefined. In particular, I acknowledge that this problem is helpful in order to bring to the fore the issue of the proper characterisation of the constraints upon the possession conditions of perceptual demonstrative concepts. Yet, I contend that, in light of the foregoing discussion, it is neutral with respect to the dispute between conceptual and non-conceptual theorists. For that dispute hinges on whether it is possible to have experiences with a certain content independently of having the concepts, which are needed for its canonical specification and not on whether those experiences are conceptualisable in all their finesse of grain. [source]

    Sale, price and valuation in Galicia and Castile,León in the tenth century

    Wendy Davies
    The number of sale transactions recorded by northern Spanish charters of the tenth century is very striking, especially in the 930s to 960s. A record of price paid was a consistent element of such documents, although words used to express price varied from silver solidi to goats, shirts and grain. Valuations, in solidi and in other units of account such as cattle, were often stated when objects were used as payment. While it looks as if some silver was really used in deals in urban León and its hinterland, using pieces of silver called argenzos, argenteos etc., elsewhere this was rare. Comparing the transactions in the three very different monastic collections of Celanova in the north,west, Sahagún in the central meseta and Cardeña in the foothills of the sierras in the north,east, regional difference is also striking. Sahagún is notable for the volume and early date of its sales and for increasing use of silver,based expressions of price and value. Round Celanova, by contrast, although there were also many sales, people used several modes of valuation simultaneously, but metal,based notions very rarely. Round Cardeña, close to urban Burgos, far fewer sales are recorded, and they come later in the century, but silver,based notions of value were the only ones used. This latter sub,urban context seems to have been much less commercially active than that of León and Sahagún, with exchange by gift and countergift a more prominent characteristic. [source]

    The behavior of specific sediment yield in different grain size fractions in the tributaries of the middle Yellow River as influenced by eolian and fluvial processes

    Jiongxin Xu
    Abstract Based on data from 35 stations on the tributaries of the Yellow River, annual specific sediment yield (Ys) in eight grain size fractions has been related to basin-averaged annual sand,dust storm days (Dss) and annual precipitation (Pm) to reveal the influence of eolian and fluvial processes on specific sediment yield in different grain size fractions. The results show that Ys in fine grain size fractions has the highest values in the areas dominated by the coupled wind,water process. From these areas to those dominated by the eolian process or to those dominated by the fluvial process, Ys tends to decrease. For relatively coarse grain size fractions, Ys has monotonic variation, i.e. with the increase in Dss or the decrease in Pm, Ys increases. This indicates that the sediment producing behavior for fine sediments is different from that for relatively coarse sediments. The results all show that Ys for relatively coarse sediments depends on the eolian process more than on the fluvial process, and the coarser the sediment fractions the stronger the dependence of the Ys on the eolian process. The Ys,Dss and Ys,Pm curves for fine grain size fractions show some peaks and the fitted straight lines for Ys,Dss and Ys,Pm relationships for relatively coarse grain size fractions show some breaks. Almost all these break points may be regarded as thresholds. These thresholds are all located in the areas dominated by the coupled wind,water process, indicating that these areas are sensitive for erosion and sediment production, to which more attention should be given for the purpose of erosion and sediment control. A number of regression equations were established, based which the effect of rainfall, sand,dust storms and surface material grain size on specific sediment yield can be assessed. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Supplementary data confirming the relationship between critical Shields stress, grain size and bed slope

    Gareth Pender
    Abstract This article presents new experimental data on threshold conditions for motion of coarse uniform sediments. The experiments were conducted with 2·8 mm gravel in a 7·5 m long by 0·3 m wide flume and included measurements of hydraulic characteristics and rate of bed particle movement for a range of flows at different bed slopes. A reference transport method was used to define the beginning of sediment motion. Results from experiments with glass balls (diameters 6 and 9 mm) and coarse uniform gravels (17·5 and 38·6 mm) conducted by other researchers were used as an additional independent data set. The experimental data confirm the recent finding that the critical Shields stress for motion of coarse uniform sediment varies with both grain size and bed slope. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    The role of mineralogy, geochemistry and grain size in badland development in Pisticci (Basilicata, southern Italy)

    V. Summa
    Abstract Mineralogical, geochemical and grain-size composition of soil and pore-water chemistry parameters were characterized on both eroded (south-facing) and non-eroded (north-facing) clayey-silt slopes in the Basilicata region (southern Italy). Only a few grain-size parameters and clay mineralogy discriminate eroded from non-eroded substrates. Compared with the latter, the former have fractions of over 63 µm and 1,4 µm lower and fractions 4,63 µm higher. Grain-size characters of crusts did not discriminate with respect to substrate. Bulk rock mineralogy was not distinctive, but the clay mineral assemblage shows that the eroded slope is enriched in kaolinite, mixed layers (illite,smectite) and chlorite, whereas illite decreases, although overlaps are common. Chemical data enable discrimination between eroded and non-eroded slopes. pH, SAR (sodium adsorption ratio), TDS (total dissolved salts) and PS (percentage of sodium) are distinctive parameters for both eroded and non-eroded slopes. TDS increases in depth in the non-eroded slope, whereas the maximum TDS is just below the crust in the eroded one. On average, eroded substrates are higher in pH, SAR and PS than non-eroded ones. The ESP (exchangeable sodium percentage) of the eroded slope has a higher value than the non-eroded one. Crusts are less dispersive than eroded substrates, and non-eroded substrates behave as crusts. This suggests that the portion of the slope most severely exposed to weathering tends to stabilize, due to strong decreases in SAR, PS and ESP. Several diagrams reported in the literature show similarly anomalous crust samples on eroded slopes, compared with other samples coming from greater depths on eroded slopes. In the present case study, the exchangeable form of Na characterizes crusts more than the soluble form. This study describes the erosional mechanism, which involves morphological and geographic exposure and climatic elements, as well as grain size, mineralogy, chemistry and exchangeable processes of soils. Copyright © 2006 John Wiley & Sons, Ltd. [source]