335 research outputs found

    Intramolecular dynamics. II. Artificial intelligence search evaluation function and treatment of resonance centers for large systems

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    The role of resonance centers in obtaining large size matrices via an artificial intelligence (AI) search is discussed. The results are used to develop for an AI search an evaluation function which takes cognizance of isolated internal resonances in these many-state systems. The effect of later-accepted states on resonance centers is included. This evaluation function and one without a resonance factor are used in Part III of this series. A search is made there to select zeroth-order vibrational states of benzene that are used in a diagonalization treatment of CH overtone spectra. When there are many overlapping resonances, as in that case, a comparison of results obtained with those two types of evaluation function is of particular interest

    Influences of Random Surface Waves on the Estimates of Wind Energy Input to the Ekman Layer in the Antarctic Circumpolar Current Region

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    Sea surface waves significantly affect the wind energy input to the Ekman layer in the upper ocean. In the study, we first incorporated the wave-induced Coriolis-Stokes forcing, the reduction of wind stress caused by wave generation, and wave dissipation into the classical Ekman model to investigate the kinetic energy balance in the wave-affected Ekman layer. Then, both the theoretical steady state solution for the idealized condition and the nonsteady state solution for the realistic ocean were derived. Total energy input to the wave-affected Ekman layer includes the wind stress energy input and the wave-induced energy input. Based on the WAVEWATCH III model, the wave spectrum was simulated to represent realistic random directional wave conditions. The wind stress energy input and the wave-induced energy input to the wave-affected Ekman layer in the Antarctic Circumpolar Current in the period from 1988 to 2010 were then calculated. The annual mean total energy input in the Antarctic Circumpolar Current region was 402.5 GW and the proportions of the wind stress energy input and the wave-induced energy input were, respectively, 85% and 15%. Particularly, total energy input in the Antarctic Circumpolar Current in the wave-affected Ekman layer model was 59.8% lower than that in the classical Ekman model. We conclude that surface waves play a significant role in the wind energy input to the Ekman layer

    The Effect of Dietary Protein Level on the Growth Performance and Digestive Protease Activity in Juvenile Bluegill (Lepomis macrochrius)

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    A 16-week feeding experiment was conducting in an indoor recirculating aquaculture system (RAS) to determine the effects of dietary protein level on the growth and digestive protease activity in juvenile bluegills. Six isocaloric experimental diets were forumalted with 32%, 35%, 38%, 41%, 44%, and 47% levels of protein. Menhdaen fish meal was use as the sole protein source. Juvenile bluegills of 24.91 ± 0.50 g initial weight were distributed into 24 151 L tanks with 12 fish each. Each diet had four replications. Fish were fed to satiation three times a day by hand. At the termination, there no mortalities in fish fed 38% through 47% protein diet. Bluegill fed 38% or 47% protein diet had significant higher body weight gain and specific growth rate (SGR) than fish fed 32% or 35% [rotein diet. No significant differences (p\u3e0.05) were found in weight gain, SGR, and FCR among the fish fed 38% or higher protein diets. Protein efficiency ratio decreased with increasing dietary protein level from 32% to 47%. Acid protease activity of complete digestive tract increased in trend with increasing dietary protein level from 32% to 47%. No significant differences were detected in the protease activity at different pH level among the treatments. The optimal dietary protein requirement for juvenile bluegill was about 38.3%.https://bluetigercommons.lincolnu.edu/lucer-pubs/1001/thumbnail.jp

    Amino Acid Profiles in the Tissues of Juvenile Bluegill (Lepomis Macrochirus) from the Wild and Commercially-fed Fish

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    Amino acid profiles of fish tissues and fish eggs have been extensively investigated in some fish species. Amino acid profiles are helpful in quantifying the indispensable amino acid requirements for these fish. Bluegill is a major forage fish for the largemouth bass (Micropterus samoides) and an important recreational fish throughout the US. The demand for bleugill as a food fish has increased recently. However, the information on the amino acid profiles of its eggs and tissues is lacking. The objectve of this study was to determine the amino acid profiles of the muscles and whole body of the 1-2 g wild and the commercially fed bluegill. Wild fish were obtained from the ponds that relied on the natural food source. Commercially fed fish were grown indoors. Skinless muscles were obtained by dissected both sides of the 1-2 g bluegill. The results showed the lysine was the most abundant indispensable amino acids in muscles and hwole body of both the wild and the farm-raised fish. The proportion of an individual indispensable amino acid to the sum of all detectable amino acids amount was similar for whole body and muscles in wild or raised fish. For whole body or muscle tissue, wild fish contained significantly higher crude protein but lower crude lipid levels than farm-raised bluegill (p\u3c0.05). This study suggested that nutritional history affected tissue proximate compositions.https://bluetigercommons.lincolnu.edu/lucer-pubs/1003/thumbnail.jp

    A mixed-methods national study investigating key challenges in learning English as a foreign language: A Chinese college student perspective

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    IntroductionThis mixed-methods national study has a two-fold purpose: (a) to invite Chinese college students to rate their overall difficulties in the eight areas of English learning, i.e., listening, speaking, reading, writing, pronunciation, grammar, vocabulary, and culture; and (b) to invite them to identify their key challenges in learning EFL. Specifically, the following three research questions were asked: (a) what are their overall difficulties in the eight areas of learning EFL? (b) Are there significant differences in rating their overall difficulties in these eight areas across the demographic variables of gender (i.e., male versus female participants) and subject discipline (arts versus sciences versus English subject disciplines participants)? And (c) what are their key challenges in learning EFL?MethodsThe participants included a sample of 1,525 freshmen and sophomore students currently studying at seven universities across China. The instrument was a survey that consisted of a five-point Likert scale self-evaluation form and a major essay question addressing their key challenges. The qualitative data can help to probe deeply into the research setting to obtain in-depth understandings about Chinese college students’ English learning; and therefore, they can greatly enhance the quantitative data.Results and discussionThe quantitative results indicated that listening, speaking, and writing were their three key difficult areas in EFL learning; further, students’ subject discipline (arts versus sciences verse English subject disciplines) had significant effects on their perceived learning challenges in English listening and vocabulary. The qualitative results confirmed that listening, speaking, and writing were their three key challenging areas. Their specific learning challenges in each area were examined. Implications for Chinese college English teachers and administrators are discussed in terms of pedagogy and policy making, respectively

    Fabrication and mechanical performance of 3D woven basalt fiber composite materials

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    Three kinds differently structural 3D woven fabrics with the basalt fiber filaments tows as warp and weft yarn were fabricated on common loom by reasonable design. And, three kinds differently structural 3D woven basalt fiber composite materials were obtained with vinyl ester resin as matrix materials and 3D woven fabrics as reinforced materials, by VARTM molding process (vacuum assisted resin transfer molding process). Then, the tensile and bending properties of three kinds differently structural 3D woven basalt fiber composite materials were tested through the universal testing machine. Results were shown that the 3D woven basalt fiber composite materials had excellent mechanical properties, but the different structures of 3D woven fabrics as reinforced materials shown a big difference on mechanical properties. As follows, the modulus of elasticity for tensile and modulus of elasticity for bending of the 3D orthogonal structure basalt fiber composite materials were the greatest, and that of the 3D throughout angle interlocking structure basalt fiber composite materials was the smallest. Meanwhile, the tensile elongation at break of the 3D throughout angle interlocking structure basalt fiber composite materials were the largest and that of the 3D layered angle interlocking structure basalt fiber composite materials was the smallest

    Evolution by gene duplication, recombination and selection in MHC class I genes of Odorrana margaretae

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    Amphibians have undergone catastrophic declines worldwide and the major histocompatibility complex (MHC) is an attractive candidate for investigating the link between adaptive variation and individual fitness. Nonetheless, little research has been conducted to study the amphibians MHC genes. Thus, MHC class Ia of Odorrana margaretae, a representative species of the Odorrana, was isolated and used to analyze the adaptive mechanism. We isolated alleles and determined evolution patterns of MHC class Ia in O. margaretae. The phylogenetic tree of MHC class Ia was reconstructed to understand the evolutionary relationship of Anura. In O. margaretae of MHC class Ia: there were more non-synonymous mutations compared to synonymous mutations; there are at least two loci; the recombination alleles took place for a large proportion (55.56%) of the alleles and recombination usually took place between whole exon of Ia genes of MHC class; positive selection sites were detected and most (10 of 19) located at the α1 and α2 domains belonged to the presumed ABS. The diversity of genes of MHC class Ia was led by recombination, gene duplication and positive selection. Trans-species polymorphisms of anuran genes of MHC class Ia were evident in anurans. Therefore, the MHC class Ia present demonstrative candidates for investigating the link between adaptive variation and individual fitness. We argue that knowledge of the MHC of other anuran lineage, especially focusing a genus such as O. margaretae, should provide an overall more complete picture of the organization of MHC in anurans

    Nanoporous Polymer Reflectors for Organic Solar Cells

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    Due to their high transparency, electrodes fabricated from conductive polymers are often implemented in semitransparent organic solar cells. Opaque solar cells usually employ metal back electrodes with high reflectivity for best photon confinement in the light-harvesting layer. Herein, a bilayer back electrode comprising conductive polymers and nanofoamed poly(methyl methacrylate) (PMMA) is investigated, the latter of which creates diffuse reflection of the incoming light. By tuning the thickness of the nanofoamed PMMA layer, absorption and transmission of the solar cells can be tailored from opaque to vastly transparent. Due to its diffusive character, this versatile electrode enhances the light absorption in the wavelength regimes with lower absorption coefficient. The solar cells are particularly suited for deployment in frosted window applications
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