Distribution by Scientific Domains
Distribution within Life Sciences

Kinds of Cover

  • algal cover
  • back cover
  • canopy cover
  • cloud cover
  • coral cover
  • crown cover
  • forest cover
  • front cover
  • grass cover
  • greater cover
  • ground cover
  • herbaceous cover
  • high cover
  • ice cover
  • impervious cover
  • land cover
  • lichen cover
  • litter cover
  • live coral cover
  • macrophyte cover
  • moss cover
  • percent cover
  • percentage cover
  • plant cover
  • seasonal snow cover
  • sedimentary cover
  • shrub cover
  • snow cover
  • soil cover
  • species cover
  • stone cover
  • total cover
  • tree canopy cover
  • tree cover
  • urban land cover
  • vegetation cover
  • vegetative cover
  • winter snow cover
  • woody cover
  • woody plant cover
  • woody vegetation cover

  • Terms modified by Cover

  • cover change
  • cover class
  • cover condition
  • cover crop
  • cover data
  • cover gradient
  • cover image
  • cover layer
  • cover picture
  • cover shows
  • cover slip
  • cover soil
  • cover type
  • cover value
  • cover variability
  • cover variable

  • Selected Abstracts


    ABSTRACT. Although snow is known to influence landform genesis and distribution, the spatial associations between snow and landforms within particular cold regions has received limited research attention. We present a case study from the high Drakensberg of southern Africa, comparing the contemporary spatial pattern of longest-lasting cold-season snow patches with the distribution patterns of active and relic cold region landforms. Two 30 m resolution sets of TM images dated 3 and 19 August 1990 and a DEM were used to demonstrate the geographic trends of snow patch depletion during late winter. Geomorphological phenomena with known coordinates were then incorporated into the GIS. The spatial distribution of several periglacial land-forms (earth hummocks, stone-/turf-banked lobes, block deposits, large sorted patterned ground) coincides with topographic positions that limit snow accumulation. However, the strong spatial association between longest-lasting snow patches and palaeo-moraines implies substantial snow accumulation at some high altitude south-facing sites during the last glacial cycle. [source]

    Tracking Fragmentation of Natural Communities and Changes in Land Cover: Applications of Landsat Data for Conservation in an Urban Landscape (Chicago Wilderness)

    Yeqiao Wang
    Within the metropolis survive some of the world's best remaining examples of eastern tallgrass prairie, oak savanna, open oak woodland, and prairie wetland. Chicago Wilderness is more than 81,000 ha of protected areas in the urban and suburban matrix. It also is the name of the coalition of more than 110 organizations committed to the survival of these natural lands. The long-term health of these imperiled communities depends on proper management of the more extensive, restorable lands that surround and connect the patches of high-quality habitat. Information critical to the success of conservation efforts in the region includes (1) a current vegetation map of Chicago Wilderness in sufficient detail to allow quantitative goal setting for the region's biodiversity recovery plan; (2) quantified fragmentation status of the natural communities; and (3) patterns of land-cover change and their effects on the vitality of communities under threat. We used multispectral data from the Landsat thematic mapper (October 1997) and associated ground truthing to produce a current vegetation map. With multitemporal remote-sensing data (acquired in 1972, 1985, and 1997), we derived land-cover maps of the region at roughly equivalent intervals over the past 25 years. Analyses with geographic information system models reveal rapid acceleration of urban and suburban sprawl over the past 12 years. Satellite images provide striking visual comparisons of land use and health. They also provide banks of geographically referenced data that make quantitative tracking of trends possible. The data on habitat degradation and fragmentation are the biological foundation of quantitative goals for regional restoration. Resumen: En Chicago hay una concentración de comunidades naturales globalmente significativas sorprendentemente alta. En la metrópolis sobreviven algunos de los mejores ejemplos mundiales remanentes de praderas de pastos orientales, sabanas de roble, bosques abiertos de roble y humedales de pradera. Chicago Wilderness es más de 81,000 ha de áreas protegidas en la matriz urbana y suburbana. También es el nombre de una coalición de más de 110 organizaciones dedicadas a la supervivencia de esas tierras naturales. La salud a largo plazo de estas comunidades amenazadas depende del manejo adecuado de las tierras, más extensas y restaurables, que rodean y conectan a los fragmentos de hábitat de alta calidad. La información crítica para el éxito de los esfuerzos de conservación en la región incluye: (1) un mapa actualizado de la vegetación de Chicago Wilderness con suficiente detalle para que la definición de metas cuantitativas para el plan de recuperación de la región sea posible; (2) cuantificación de la fragmentación de las comunidades naturales y (3) patrones de cambio de cobertura de suelo y sus efectos sobre la vitalidad de las comunidades amenazadas. Utilizamos datos multiespectrales del mapeador temático Landsat (octubre 1997) y verificaciones de campo asociadas para producir el mapa actualizado de vegetación. Con datos de percepción remota multitemporales (obtenidos en 1972, 1985 y 1997), derivamos los mapas de cobertura de suelo en la región en intervalos equivalentes en los últimos 25 años. El análisis de los modelos SIG revela una rápida aceleramiento del crecimiento urbano y suburbano en los últimos 12 años. Las imágenes de satélite proporcionan comparaciones visuales notables del uso y condición del suelo. También proporcionan bancos de datos referenciados geográficamente que hacen posible el rastreo de tendencias cuantitativas. Los datos de degradación y fragmentación del hábitat son la base biológica de metas cuantitativas para la restauración regional. [source]

    The role of environmental gradients in non-native plant invasion into burnt areas of Yosemite National Park, California

    Rob Klinger
    ABSTRACT Fire is known to facilitate the invasion of many non-native plant species, but how invasion into burnt areas varies along environmental gradients is not well-understood. We used two pre-existing data sets to analyse patterns of invasion by non-native plant species into burnt areas along gradients of topography, soil and vegetation structure in Yosemite National Park, California, USA. A total of 46 non-native species (all herbaceous) were recorded in the two data sets. They occurred in all seven of the major plant formations in the park, but were least common in subalpine and upper montane conifer forests. There was no significant difference in species richness or cover of non-natives between burnt and unburnt areas for either data set, and environmental gradients had a stronger effect on patterns of non-native species distribution, abundance and species composition than burning. Cover and species richness of non-natives had significant positive correlations with slope (steepness) and herbaceous cover, while species richness had significant negative correlations with elevation, the number of years post-burn, and cover of woody vegetation. Non-native species comprised a relatively minor component of the vegetation in both burnt and unburnt areas in Yosemite (percentage species = 4%, mean cover < 6.0%), and those species that did occur in burnt areas tended not to persist over time. The results indicate that in many western montane ecosystems, fire alone will not necessarily result in increased rates of invasion into burnt areas. However, it would be premature to conclude that non-native species could not affect post-fire succession patterns in these systems. Short fire-return intervals and high fire severity coupled with increased propagule pressure from areas used heavily by humans could still lead to high rates of invasion, establishment and spread even in highly protected areas such as Yosemite. [source]

    Inside Front Cover (Adv. Eng.

    Intense mobility of an osteoblast (actin, green) on a plasma activated surface leaving footprints of fibronectin (red). [source]

    Inside Front Cover (Adv. Eng.

    Surface roughness is another important factor impacting cell behavior and AFM is utilized to determine the surface morphology. The Cover shows the surface morphology measured by AFM obtained from O2 PIII PTFE. More details can be found in the article of Paul K. Chu on p. B163. [source]

    Back Cover: Fundamentals of Metal-induced Crystallization of Amorphous Semiconductors (Adv. Eng.

    The Backcover shows a covering layer of aluminum lowers the crystallization temperature of amorphous silicon (a-Si). First the a-Si covers ("wets") the grain boundaries in the aluminum layer (Al). Once the wetting a-Si film has reached a critical thickness, crystallization starts at the grain boundaries. More details can be found in the article by E. J. Mittemeijer on page 131. [source]

    Inside Front Cover ,Advanced Biomaterials 1/2009

    Andrés F. Lasagni
    The cover picture by Lasagni et. al shows two-dimensional periodic microstructures of polyethylene glycol diacrylate (PEG-DA) fabricated using nanosecond (top) and femtosecond (bellow) multibeam laser interference patterning (MLI). The periodic topography can be varied by simple control of the interference patterns as well as exposure dosages. Such structures with controlled topography are of relevant importance for applications in biomedical devices. [source]

    Ultrasonic Metal Welding of Aluminium Sheets to Carbon Fibre Reinforced Thermoplastic Composites (Adv. Eng.

    The Cover shows a hybrid joint for multi-material lightweight components realized by ultrasonic metal welding at the Institute of Materials Science and Engineering at the University of Kaiserslautern. Ultrasonic welding is one innovative technology for joining carbon fibre reinforced polymers (CFRP) with sheet metals like aluminium alloys or aluminium plated steels. The achievable mechanical properties of the ultrasonic welded joints were carried out by using statistical test methods. One example for the evaluation of the welding results is presented on the left hand side of the Cover. Additionally a scanning electron micrograph of the bonding zone of an aluminium/CFRP-joint is shown in the background. More details about the ultrasonic welding technique can be found in the article of F. Balle, G. Wagner and D. Eifler on page 35 of this issue. [source]

    Back Cover: TMS Bulk-Metallic Glasses Symposium V (Adv. Eng.

    The backcover shows the nanoindentation of a Zr-based bulk metallic glass with an Al-concentration of 13 at%. Around the indent shear bands are observed indicating some plasticity of that glass. More about the glass-forming ability and ductility of Zr-based and Al-rich bulk metallic glasses can be found in the paper by R. Wunderlich et al. on page 1020. [source]

    Inside Front Cover Advanced Biomaterials 2/2008)

    Article first published online: 27 OCT 200
    No abstract is available for this article. [source]

    Inside Front Cover: Novel Engineered Ion Channel Provides Controllable Ion Permeability for Polyelectrolyte Microcapsules Coated with a Lipid Membrane (Adv. Funct.

    In their Full Paper on page 201, Donald Martin and co-workers describe the covering of polyelectrolyte microcapsules with a lipid bilayer that incorporates a novel engineered ion channel to provide a functional capability to control transport across the microcapsule wall. The cover image shows atomic-force microscopy images of these 8-layer polyelectroctrolyte capsules recorded using tapping mode in an aqueous environment. The capsules can be seen to collapse in a folded manner, with an occasional wrinkle that "absorbs" the extra surface area when flattening the spherical surface. [source]

    Inside Front Cover: A Unique Microcracking Process Associated with the Inelastic Deformation of Haversian Bone (Adv. Funct.

    Human cortical bone is capable of adapting to the mechanical environment through dynamic remodeling of the Haversian systems. The presence of Haversian canals, however, also introduces stress concentration and could have detrimental effects on the fracture resistance of bone. How is the hierarchical structure in bone designed to alleviate such stress concentrations? On page 57, Vincent Ebacher and Rizhi Wang report a unique and stable microcracking process accompanying the inelastic deformation of Haversian bone. The results lead to the critical role of the well-organized bone lamellae surrounding each Haversian canal. [source]

    Estimating Ground Water Recharge from Topography, Hydrogeology, and Land Cover

    GROUND WATER, Issue 1 2005
    Douglas S. Cherkauer
    Proper management of ground water resources requires knowledge of the rates and spatial distribution of recharge to aquifers. This information is needed at scales ranging from that of individual communities to regional. This paper presents a methodology to calculate recharge from readily available ground surface information without long-term monitoring. The method is viewed as providing a reasonable, but conservative, first approximation of recharge, which can then be fine-tuned with other methods as time permits. Stream baseflow was measured as a surrogate for recharge in small watersheds in southeastern Wisconsin. It is equated to recharge (R) and then normalized to observed annual precipitation (P). Regression analysis was constrained by requiring that the independent and dependent variables be dimensionally consistent. It shows that R/P is controlled by three dimensionless ratios: (1) infiltrating to overland water flux, (2) vertical to lateral distance water must travel, and (3) percentage of land cover in the natural state. The individual watershed properties that comprise these ratios are now commonly available in GIS data bases. The empirical relationship for predicting R/P developed for the study watersheds is shown to be statistically viable and is then tested outside the study area and against other methods of calculating recharge. The method produces values that agree with baseflow separation from streamflow hydrographs (to within 15% to 20%), ground water budget analysis (4%), well hydrograph analysis (12%), and a distributed-parameter watershed model calibrated to total streamflow (18%). It has also reproduced the temporal variation over 5 yr observed at a well site with an average error < 12%. [source]

    Jobs, Houses, and Trees: Changing Regional Structure, Local Land-Use Patterns, and Forest Cover in Southern Indiana

    GROWTH AND CHANGE, Issue 3 2003
    Darla K. Munroe
    Land-use and -cover change is a topic of increasing concern as interest in forest and agricultural land preservation grows. Urban and residential land use is quickly replacing extractive land use in southern Indiana. The interaction between land quality and urban growth pressures is also causing secondary forest growth and forest clearing to occur jointly in a complex spatial pattern. It is argued that similar processes fuel the abandonment of agricultural land leading to private forest regrowth, changes in topography and land quality, and declining real farm product prices. However, the impact of urban growth and development on forests depends more strongly on changes in both the residential housing and labor markets. Using location quotient analysis of aggregate employment patterns, and the relationship between regional labor market changes, the extent of private forest cover was examined from 1967 to 1998. Then an econometric model of land-use shares in forty southern Indiana counties was developed based on the net benefits to agriculture, forestland, and urban uses. To test the need to control explicitly for changes in residential demand and regional economic structure, a series of nested models was estimated. Some evidence was found that changing agricultural profitability is leading to private forest regrowth. It was also uncovered that the ratio of urban to forest land uses is better explained by incorporating measures of residential land value and industrial concentration than simply considering population density alone. [source]

    Direction-Dependent Homoepitaxial Growth of GaN Nanowires,

    ADVANCED MATERIALS, Issue 2 2006
    H. Li
    GaN nanowires with vastly different morphologies depending upon the growth direction are produced by direct nitridation and vapor transport of Ga in disassociated ammonia. Nanowires grown homoepitaxially along the c -direction develop hexagonal-prism island morphologies (see Figure, left, and Cover), while wires grown along the a -direction form uniform, belt-shaped morphologies (Figure, right). A "ballistic" transport phenomenon for adatoms is proposed to explain the observed prismatic island morphologies. [source]

    A comparison of regeneration dynamics following gap creation at two geographically contrasting heathland sites

    A.J. Britton
    1.,Lowland Calluna -dominated heathlands are a high priority for conservation in Europe. As an anthropogenic subclimax community they require regular management intervention to maintain their conservation interest. 2.,Increasingly, Calluna is disappearing from lowland heathlands and being replaced by grasses, especially in the Netherlands and more recently in south-east England. While Calluna is highly competitive over much of its life cycle, its competitive ability is reduced during the regeneration phase that follows the death of stands or results from management activity. 3.,We examined the influence of five factors on regeneration of vegetation in gaps in two broadly similar lowland dry heaths over a 3-year period. These were: geographical location (combining a variety of environmental contrasts); dominant species (Calluna or grasses); management techniques; gap size; and seed source availability. 4.,Site location had the greatest effect on patterns of regeneration. Regeneration on the Wirral (north-west England) was faster and more dominated by Calluna than regeneration in Breckland (south-east England), which was dominated by other species including grasses and annual plants. Addition of Calluna seed at the Breckland site failed to increase Calluna cover. It was concluded that climatic or other environmental factors were the most probable cause of poor regeneration. 5.,Cover of grasses in regenerating areas was greatest in Breckland, where Deschampsia was able to establish in all gaps where there was a seed source (either in the surrounding vegetation or applied as a treatment). On the Wirral, Deschampsia establishment was limited, even in gaps where a seed source was applied. 6.,This work has implications for the conservation management of heathlands, which currently follows a standard prescription throughout the UK. It is suggested that management regimes should be tailored to suit the conditions prevailing at individual sites as regeneration dynamics may be extremely variable. [source]

    Journal of Cellular Physiology: Volume 225, Number 1, October 2010

    Article first published online: 5 AUG 2010
    Cover is a schematic of migration within the leukemic stem cell (LSC) niches of the bone marrow endosteal space in relationship with their different components. Please see mini-review in this issue by Sengupta and Cancelas, pages 7,14. [source]

    Effects of Watershed Impervious Cover on Dissolved Silica Loading in Storm Flow,

    Socratis Loucaides
    Abstract:, Dissolved silica (DSi) availability is a factor that affects the composition of algal populations in aquatic ecosystems. DSi cycling is tightly linked to the hydrological cycle, which is affected by human alterations of the landscape. Development activities that increase impervious cover change watershed hydrology and may increase the discharge of DSi-poor rainwater and decrease the discharge of DSi-rich ground water into aquatic ecosystems, possibly shifting algal community composition toward less desirable assemblages. In this study, DSi loadings from two adjacent coastal watersheds with different percent impervious cover were compared during four rain and five nonrain events. Loadings in the more impervious watershed contained a significantly larger proportion of surface runoff than base flow (ground-water discharge) and had lower [DSi] water during rain events than the less impervious watershed. Application of the Soil Conservation Service Curve Number (CN) method showed that the minimum rainfall height necessary to yield runoff was significantly lower for the more impervious watershed, implying that runoff volumes increase with impervious cover as well as the frequency of runoff-yielding events. Empirical data collected during this study and estimates derived from the CN method suggest that impervious cover may be responsible for both short-term DSi limitation during rain events as well as long-term reduction of DSi inputs into aquatic ecosystems. [source]

    Effects of Impervious Cover at Multiple Spatial Scales on Coastal Watershed Streams,

    Roy Schiff
    Abstract:, The spatial scale and location of land whose development has the strongest influence on aquatic ecosystems must be known to support land use decisions that protect water resources in urbanizing watersheds. We explored impacts of urbanization on streams in the West River watershed, New Haven, Connecticut, to identify the spatial scale of watershed imperviousness that was most strongly related to water chemistry, macroinvertebrates, and physical habitat. A multiparameter water quality index was used to characterize regional urban nonpoint source pollution levels. We identified a critical level of 5% impervious cover, above which stream health declined. Conditions declined with increasing imperviousness and leveled off in a constant state of impairment at 10%. Instream variables were most correlated (0.77 , |r| , 0.92, p < 0.0125) to total impervious area (TIA) in the 100-m buffer of local contributing areas (,5-km2 drainage area immediately upstream of each study site). Water and habitat quality had a relatively consistent strong relationship with TIA across each of the spatial scales of investigation, whereas macroinvertebrate metrics produced noticeably weaker relationships at the larger scales. Our findings illustrate the need for multiscale watershed management of aquatic ecosystems in small streams flowing through the spatial hierarchies that comprise watersheds with forest-urban land use gradients. [source]

    Temporal dynamics of marginal steppic vegetation over a 26-year period of substantial environmental change

    Silvia Matesanz
    Abstract Questions: (1) Is climate a strong driver of vegetation dynamics, including interannual variation, in a range margin steppic community? (2) Are there long-term trends in cover and species richness in this community, and are these consistent across species groups and species within groups? (3) Can long-term trends in plant community data be related to variation in local climate over the last three decades? Location: A range margin steppic grassland community in central Germany. Methods: Cover, number and size of all individuals of all plant species present in three permanent 1-m2 plots were recorded in spring for 26 years (1980,2005). Climatic data for the study area were used to determine the best climatic predictor for each plant community, functional group and species variable (annual data and interannual variation) using best subsets regression. Results: April and autumn temperature showed the highest correlation with total cover and species richness and with interannual variations of cover and richness. However, key climate drivers differed between the five most abundant species. Similarly, total cover and number and cover of perennials significantly decreased over time, while no trend was found for the cover and number of annuals. However, within functional groups there were also contrasting species-specific responses. Long-term temperature increases and high interannual variability in both temperature and precipitation were strongly related to long-term trends and interannual variations in plant community data. Conclusions: Temporal trends in vegetation were strongly associated with temporal trends in climate at the study site, with key roles for autumn and spring temperature and precipitation. Dynamics of functional groups and species within groups and their relationships to changes in temperature and precipitation reveal complex long-term and interannual patterns that cannot be inferred from short-term studies with only one or a few individual species. Our results also highlight that responses detected at the functional group level may mask contrasting responses within functional groups. We discuss the implications of these findings for attempts to predict the future response of biodiversity to climate change. [source]

    Cover Picture: Laser Phys.

    It's known that single crystals of germanate melilites, such as Ba2ZnGe2O7 and Sr2MgGe2O7, show a congruent melting behavior at about 1450 °C. Crystals of Sr2MgGe2O7 were grown from melt of stoichiometric composition by the Czochralski technique using a seed crystal orientation (and pulling direction) along [001], a pulling velocity of 2,3 mm/h and crystal rotation of 40,60 rad/min. For single crystal growth of Ba2ZnGe2O7 a melt with a surplus of ,4 wt.% BaO and ,5 wt.% GeO2 proved to be useful. Grown crystals are of dimensions up to 25 mm in length and 18 mm in diameter for Sr2MgGe2O7 and of up to 15 mm in length and in diameter for Ba2ZnGe2O7. In Cover picture an example of a grown crystal of Sr2MgGe2O7 is presented. (Cover picture: A.A. Kaminskii, L. Bohatý, et al., pp. 528,543, in this issue) (© 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

    Effect of Cloud Cover on UVB Exposure Under Tree Canopies: Will Climate Change Affect UVB Exposure?

    Richard H. Grant
    ABSTRACT The effect of cloud cover on the amount of solar UV radiation that reaches pedestrians under tree cover was evaluated with a three-dimensional canopy radiation transport model. The spatial distribution of UVB irradiance at the base of a regular array of spherical tree crowns was modeled under the full range of sky conditions. The spatial mean relative irradiance (I), and erythemal irradiance of the entire below-canopy domain and the spatial mean relative irradiance and erythemal irradiance in the shaded regions of the domain were determined for solar zenith angles from 15° to 60°. The erythemal UV irradiance under skies with 50% or less cloud cover was not remarkably different from that under clear skies. In the shade, the actual irradiance was greater under partly cloudy than under clear skies. The mean ultraviolet protection factor for tree canopies under skies with 50% or less cloud cover was nearly equivalent to that for clear sky days. Regression equations of spatially averaged Ir. as a function of cloud cover fraction, solar zenith angle and canopy cover were used to predict the variation in erythemal irradiance in different land uses across Baltimore, MD. [source]

    Inside Back Cover (Phys. Status Solidi A 5/2010)

    J. H. Leach
    The Feature Article by Morkoç and co-workers (pp. 1091,1100) centers around the not so intuitive phenomena in two types of GaN based devices, namely InGaN based LEDs and InAlN barrier GaN heterojunction FETs. In terms of the LEDs, the paper uncovers that the quantum efficiency degradation observed at high current injection levels is not necessarily of Auger recombination origin. Furthermore, nearly similar behavior of LEDs on c-plane and mplane suggests that the main driving force for the efficiency degradation is not polarization induced field either. The data along with their interpretation should set the stage for an accurate physics- based model to be developed. In terms of the FETs, the authors show that there is an optimum sheet density, which depends on drain bias or the electric field in the channel, at which the LO phonon lifetime is shortest, the velocity is highest, and the device degradation is least. The average optimum density is near 7 × 1012 cm,2 which challenges the proverbial notion that the higher the sheet density the better it is. Another outcome of this discussion is that heat dissipation takes the route of hot electrons giving off heat to LO phonons which in turn give it to LA phonons when they decay. Naturally, the shortest LO phonon lifetime is best for heat removal and thus the devices are more reliable in addition to electrons traversing at the highest velocity. [source]

    Back Cover (Phys. Status Solidi A 4/2010)

    Silvia Giudicatti
    In their Editor's Choice article on p. 935, Marabelli and coworkers present a study of plasmonic resonances in 2D planar periodic structures, which are constructed by colloidal lithography on gold/polymer surfaces. Strong interplay between plasmonic modes on both sample sides is found. The SEM image, top left on the back cover, shows the nanostructured gold/polymer surface: a residual polystyrene sphere from lithography is in the centre, whereas the top of acrylic acid pillars appear black. Reflectance from this surface passing through the glass substrate was investigated in a flowing cell, as depicted in the sketch on the right. Below, there is the map of angle dispersion of reflectance: lines represent the ideal plasmon polariton dispersion at the gold/glass and gold/air surfaces (solid lines) and the Wood anomalies (dashed lines). [source]

    Inside Back Cover: Phys.

    Status Solidi C 7/7-
    This figure is the composition of two different spatially resolved electroluminescence measurements taken on a green InGaN-based light-emitting diode (LED). The false-color scale describes the spatial distribution of light emitted by the analyzed device, under two different bias conditions. The image on the left was taken under a forward bias of 10 ,A, while the image on the right was taken with a reverse bias of ,10 ,A. As can be noticed, InGaN-based LEDs can emit a weak luminescence signal even under reverse-bias conditions. Reverse-bias luminescence can be ascribed to the recombination of electrons that are injected within the active region by tunneling, as described by Meneghini et al. on page 2208ff. Electroluminescence microscopy represents a powerful tool for the investigation of the electrooptical characteristics of GaN-based devices and for the analysis of the physical mechanisms responsible for their degradation. [source]

    An investigation of Detect, Practice, and Repair to remedy math-fact deficits in a group of third-grade students

    Brian C. Poncy
    A multiple-probe-across-problem-sets (tasks) design was used to evaluate the effects of the Detect, Practice, and Repair (DPR) on multiplication-fact fluency development in seven third-grade students nominated by their teacher as needing remediation. DPR is a multicomponent intervention and begins with a group-administered, metronome-paced assessment used to identify specific facts in need of repair. Next, Cover, Copy, and Compare (CCC) procedures are used to enhance automaticity with those specific facts. Lastly, students complete a 1-min speed drill and self-graph their fluency performance. Results showed large level and trend increases in fact fluency after DPR was applied across all three sets of multiplication problems. Discussion focuses on the importance of developing effective and efficient basic-skill-remediation procedures and directions for future research. © 2010 Wiley Periodicals, Inc. [source]

    Front and Back Covers, Volume 25, Number 1.

    ANTHROPOLOGY TODAY, Issue 1 2009
    February 200
    Front cover caption, volume 25 issue 1 A boy shows off on his horse at the annual festival of racing, games and music in Barsko'on, Kyrgyzstan in October 2007. The festival includes endurance races of up to 36 kilometres over steep, rocky mountain paths and streams, a far cry from the bowling-green surfaces of Churchill Downs and Newmarket. Abdildechan, an expert in horse games in Kyzyl Suu, explained that horse games and competitions such as these derive from the importance of horses to the nomadic and warrior traditions of the Kyrgyz people. Horses enable people to move away from danger, he explained, and are also essential for work and food. Cars are becoming increasingly common in Kyrgyzstan, but many people believe that they will never completely replace horses in this mountainous region. ,Young people may have cars', says shepherd Jakshylyck Orgochor, ,but where there is a Kyrgyz person there is always a horse: a horse is a man's wings'. In this issue, Rebecca Cassidy scrutinizes claims about the distinctiveness of the Kyrgyz horse and considers the political consequences of evaluating domesticated animals on the basis of contested categories including ,breed' and ,type'. Back Cover: HUMAN-ANIMAL RELATIONS Ros Coard, lecturer in archaeology and specialist in archaeozoology and forensic taphonomy in the Department of Archaeology and Anthropology at the University of Wales Lampeter, examines forensic evidence taken from the scene of a suspected big cat kill in West Wales, UK. The skulls in the foreground belong to an array of known big cat species, and Coard compared tooth pit data from these skulls with those found in sheep and horses killed in unusual circumstances. These data have been used to provide evidence for the existence of at least one large predatory felid in West Wales. However, even without this scientific corroboration, many people around the UK report sightings of non-endemic ,alien' big cats (ABCs) on a regular basis, attributing to them an almost mythical status, and this makes them an interesting phenomenon to be considered from an anthropological perspective. Coard has been working collaboratively with Samantha Hurn, an anthropologist who has been documenting narratives relating to big cat sightings in West Wales. In this issue of ANTHROPOLOGY TODAY, Hurn outlines the data collected so far. She argues that ABCs do, indeed, exist in West Wales, and discusses how and why her informants from the local Welsh farming community regard these predators in positive terms. Many see ABCs as both important keystone species performing the valuable function of keeping other problematic predators (notably foxes) in check, and highly politicized animals who symbolize their own marginalized position within contemporary UK society. As Lévi-Strauss put it long ago, animal-human relations are, indeed, good to think with. [source]

    Messung der Betondeckung , Auswertung und Abnahme

    Wolfgang Brameshuber Prof. Dr.-Ing.
    Abstract Eine Möglichkeit an fertigen Betonbauteilen die Zuverlässigkeit der Ausführungsergebnisse zu beurteilen, ist die Messung der Betondeckung. Aufgrund der bauseitig nicht zu vermeidenden Streuungen ist die Betondeckung keine feste geometrische Größe, sondern unterliegt einer statistischen Verteilung. Es wird ein Näherungsverfahren zur Auswertung der Betondeckungsmessung vorgestellt, das mit einfachster Rechnerausstattung genutzt werden kann. Anwendung findet dieses Näherungsverfahren als quantitativer Nachweis im DBV-Merkblatt ,Betondeckung und Bewehrung", Fassung Juli 2002. Measurement of Concrete Cover , Evaluation and Approval The measurement of concrete cover is a method to estimate the quality of building execution. The concrete cover is a probabilistic dimension. The paper gives an approximate method basing on the Neville-distribution to evaluate the results of a concrete cover measurement. This approximation is usable with simple software. The approximate method is used in a code of practice "Concrete Cover and Reinforcement" of the German Society for Concrete and Construction Technology (DBV). [source]

    Inside Cover: (Chem. Eur.

    CHEMISTRY - A EUROPEAN JOURNAL, Issue 31 2010 is a comprehensive free-to-view news and information site with an associated magazine, ChemViews, provided by ChemPubSoc Europe and its publisher, Wiley-VCH. The new site enhances ChemPubSoc Europe's and Wiley-VCH's suite of market-leading peer-reviewed journals like Chemistry,A European Journal. ChemViews offers news, commentary, opinion, and additional feature material from leading authors to the global chemistry community. Sign in for a free newsletter at (cover by Heulwen M.,M. Price). [source]

    Inside Cover: Iodine-Catalyzed Highly Diastereoselective Synthesis of trans -2,6-Disubstituted-3,4-Dihydropyrans: Application to Concise Construction of C28,C37 Bicyclic Core of (+)-Sorangicin,A (Chem. Eur.


    No abstract is available for this article. [source]