5,865 research outputs found

    LANDSAT/coastal processes

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    The author has identified the following significant results. Correlations between the satellite radiance values water color, Secchi disk visibility, turbidity, and attenuation coefficients were generally good. The residual was due to several factors including systematic errors in the remotely sensed data, errors, small time and space variations in the water quality measurements, and errors caused by experimental design. Satellite radiance values were closely correlated with the optical properties of the water

    Discourse and identity in a corpus of lesbian erotica

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    This article uses corpus linguistic methodologies to explore representations of lesbian desires and identities in a corpus of lesbian erotica from the 1980s and 1990s. We provide a critical examination of the ways in which “lesbian gender,” power, and desire are represented, (re-)produced, and enacted, often in ways that challenge hegemonic discourses of gender and sexuality. By examining word frequencies and collocations, we critically analyze some of the themes, processes, and patterns of representation in the texts. Although rooted in linguistics, we hope this article provides an accessible, interdisciplinary, and timely contribution toward developing understandings of discursive practices surrounding gender and sexuality

    Mechanical characterization and analysis of tensile fracture modes of ultrasonically stir cast Al6082 composites reinforced with Cu powder premixed Metakaolin particles

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    The major drawback observed in the ceramic particles reinforced aluminium matrix composites (AMCs) is the reduction of ductility. Incorporating fine metallic particles along with the ceramic reinforcements in the aluminium matrix tends to improve the ductility of the AMCs. This work highlights the effects of dispersing micro (5-10 μm) copper (Cu) particles along with the nano (100-400 nm) Metakaolin particles in the Al6082 matrix. The Metakaolin particles were premixed with Cu powder by means of manual stirring followed by ball milling before embedding into the Al6082 matrix. The total reinforcement composition was maintained as 7.5 wt.% in which 2.5 wt.% consisted of Cu powder. The composites were synthesized using ultrasonication-aided stir casting process. The composites samples were subjected to T6 heat treatment before performing mechanical characterization. The composites with Cu powder premixed Metakaolin particles showed improvement in tensile strength, ductility, compressive strength and hardness. The microstructure evaluation of the composites was performed by Scanning Electron Microscope (SEM) and Optical Microscope (OM). The tensile fracture modes were studied by analysing the fracture surface morphology using SEM

    Methods for recording and measuring tonic GABAA receptor-mediated inhibition

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    Tonic inhibitory conductances mediated by GABA(A) receptors have now been identified and characterized in many different brain regions. Most experimental studies of tonic GABAergic inhibition have been carried out using acute brain slice preparations but tonic currents have been recorded under a variety of different conditions. This diversity of recording conditions is likely to impact upon many of the factors responsible for controlling tonic inhibition and can make comparison between different studies difficult. In this review, we will firstly consider how various experimental conditions, including age of animal, recording temperature and solution composition, are likely to influence tonic GABA(A) conductances. We will then consider some technical considerations related to how the tonic conductance is measured and subsequently analyzed, including how the use of current noise may provide a complementary and reliable method for quantifying changes in tonic current

    EXPRESS: Trajectories of verbal fluency and executive functions in multilingual and monolingual children and adults: A cross-sectional study

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    The development of verbal fluency is associated with the maturation of executive function skills, such as the ability to inhibit irrelevant information, shift between tasks and hold information in working memory. Some evidence suggests that multilinguistic upbringing may underpin disadvantages in verbal fluency and lexical retrieval, but can also afford executive function advantages beyond the language system including possible beneficial effects in older age. This study examined the relationship between verbal fluency and executive function in 324 individuals across the lifespan by assessing the developmental trajectories of English monolingual and multilingual children aged 7 to 15 years (N=154) and adults from 18 to 80 years old (N=170). The childhood data indicated patterns of improvement in verbal fluency and executive function skills as a function of age. Multilingual and monolingual children had comparable developmental trajectories in all linguistic and non-linguistic measures used in the study with the exception of planning, for which monolingual children showed a steeper improvement over the studied age range relative to multilingual children. For adults, monolinguals and multilingual participants had comparable performance on all measures with the exception of non-verbal inhibitory control and response times on the Tower of London task: monolinguals showed a steeper decline associated with age. Exploratory factor analysis indicated that verbal fluency was associated with working memory and fluid intelligence in monolingual participants but not in multilinguals. These findings raise the possibility that early acquisition of an additional language may impact on the development of the functional architecture serving high-level human cognition

    Tilings of Annular Region

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    We present our summer research on mathematical tiling. We classified which rectangular annular regions are tileable by the set of T and skew tretrominoes. We present a partial proof of this result, and discuss some of the context for this problem

    Competitive Tiling

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    Competitive tiling consists of two players, a tile set, a region, and a non-negative integer d. Alice and Bob, our two players, alternate placing tiles on the untiled squares of the region. They play until no more tiles can be placed. Alice wins if at most d squares are untiled at the end of the game, and Bob wins if more than d squares are untiled. For given regions and tile sets we are interested in the smallest value of d such that Alice has a winning strategy. We call this the game tiling number. In this project, we focus on finding the game tiling number for the game played with dominoes on 2 x n rectangles, modified 2 x n rectangles, and rectangular annular regions

    Water Temperature and Harmful Algal Bloom Rate

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    Harmful algal blooms, made up of cyanobacteria, is an increasing problem in Midwestern lakes. Nitrogen and phosphorus fertilizers used in crops such as corn and soybeans run off into streams and eventually lakes. Nitrogen and phosphorus in the form of nitrate and phosphate respectively is then used by cyanobacteria as a food source, allowing them to bloom at an alarming rate. Massive bloom events can be hazardous to both human health and the natural environment because of the release of neurotoxins, hepatotoxins and others into the air and drinking water. We set out to find if different water temperature can affect the rate at which cyanobacteria can use nitrate. Six different species of cyanobacteria were analyzed. For each species, two solutions with known amounts of nitrate and excess phosphate were mixed, with one solution kept at 31 degrees Celsius and the other kept at room temperature. Overtime, the concentration of nitrate was measured. We found that, on average, the species kept at a higher temperature were able to use nitrate faster than their colder counterpart

    Probing GABAA receptors with inhibitory neurosteroids

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    γ-aminobutyric acid type A receptors (GABAARs) are important components of the central nervous system and they are functionally tasked with controlling neuronal excitability. These receptors are subject to post-translational modification and also to modulation by endogenous regulators, such as the neurosteroids. These modulators can either potentiate or inhibit GABAAR function. Whilst the former class of neurosteroids are considered to bind to and act from the transmembrane domain of the receptor, the domains that are important for the inhibitory neurosteroids remain less clear. In this study, we systematically compare a panel of recombinant synaptic-type and extrasynaptic-type GABAARs expressed in heterologous cell systems for their sensitivity to inhibition by the classic inhibitory neurosteroid, pregnenolone sulphate. Generally, peak GABA current responses were inhibited less compared to steady-state currents, implicating the desensitised state in inhibition. Moreover, pregnenolone sulphate inhibition increased with GABA concentration, but showed minimal voltage dependence. There was no strong dependence of inhibition on receptor subunit composition, the exception being the ρ1 receptor, which is markedly less sensitive. By using competition experiments with pregnenolone sulphate and the GABA channel blocker picrotoxinin, discrete binding sites are proposed. Furthermore, by assessing inhibition using site-directed mutagenesis and receptor chimeras comprising α, β or γ subunits with ρ1 subunits, the receptor transmembrane domains are strongly implicated in mediating inhibition and most likely the binding location for pregnenolone sulphate in GABAARs

    Evidence of an advantage in visuo-spatial memory for bilingual compared to monolingual speakers

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    Previous research has indicated that bilinguals outperform monolinguals in cognitive tasks involving spatial working memory. The present study examines evidence for this claim using a different and arguably more ecologically valid method (the change blindness task). Bilingual and monolingual participants were presented with two versions of the same scenes and required to press a key as soon as they identified the alteration. They also completed the word and alpha span tasks, and the Corsi blocks task. The results in the change blindness task, controlled for group differences in non-verbal reasoning, indicated that bilinguals were faster and more accurate than monolinguals at detecting visual changes. Similar group differences were found on the Corsi block task. Unlike previous findings, no group differences were found on the verbal memory tasks. The results are discussed with reference to mechanisms of cognitive control as a locus of transfer between bilingualism and spatial working memory tasks
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