98 research outputs found

    Frequency Dependent Specific Heat from Thermal Effusion in Spherical Geometry

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    We present a novel method of measuring the frequency dependent specific heat at the glass transition applied to 5-polyphenyl-4-ether. The method employs thermal waves effusing radially out from the surface of a spherical thermistor that acts as both a heat generator and thermometer. It is a merit of the method compared to planar effusion methods that the influence of the mechanical boundary conditions are analytically known. This implies that it is the longitudinal rather than the isobaric specific heat that is measured. As another merit the thermal conductivity and specific heat can be found independently. The method has highest sensitivity at a frequency where the thermal diffusion length is comparable to the radius of the heat generator. This limits in practise the frequency range to 2-3 decades. An account of the 3omega-technique used including higher order terms in the temperature dependency of the thermistor and in the power generated is furthermore given.Comment: 17 pages, 15 figures, Substantially revised versio

    Approximate square-root-time relaxation in glass-forming liquids

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    We present data for the dielectric relaxation of 43 glass-forming organic liquids, showing that the primary (alpha) relaxation is often close to square-root-time relaxation. The better an inverse power-law description of the high-frequency loss applies, the more accurately is square-root-time relaxation obeyed. These findings suggest that square-root-time relaxation is generic to the alpha process, once a common view, but since long believed to be incorrect. Only liquids with very large dielectric losses deviate from this picture by having consistently narrower loss peaks. As a further challenge to the prevailing opinion, we find that liquids with accurate square-root-time relaxation cover a wide range of fragilities

    Addressing Behavioural Issues and Optimizing Academic Concentration through Yoga among Adolescents in High School

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    Objective: This article attempts to address the de-accelerating issues and challenges faced by adolescence students in high schools and assess the impact of Yoga on the young minds optimizing their academic concentration. Concentration is an important cognitive function of the human brain which is vital for the young knowledge seeker. Methodology: The present article approached the ‘middle adolescent’ students (N=212) consisting of Bordumsa Circle (n¹=62) in Arunachal Pradesh and Margherita Block (n²=150) of Assam, respectively through a mixed method research design to comprehensively examine the conception of high school students aging between 14-16 years. Findings: The study found that 79% adolescence affected by low self-esteem; 74.19% have shown issues with good moral behaviour; 70.96% were able to understand and accept the growth and development taking place in one’s life; 67.74% experience of behavioural disorders; 61.29% were affected by learning disorders; and 64.3 % accepted that through practicing regular yoga it optimizes academic concentration. Conclusion and Suggestion: Overlooking the utility of yoga in such contexts would create an ‘Achilles Heel’ in the education system of today which aims at the overall development of the students. The study can assist learners, parents, school administrators, educationists as well as for futuristic scope of research

    Single-order-parameter description of glass-forming liquids:A one-frequency test

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    Thermo-viscoelastic linear-response functions are calculated from the master equation describing viscous liquid inherent dynamics. From the imaginary parts of the frequency-dependent isobaric specific heat, isothermal compressibility, and isobaric thermal expansion coefficient, we define a "linear dynamic Prigogine-Defay ratio" with the property that if this quantity is unity atone frequency, then it is unity at all frequencies. This happens if and only if there is a single-order-parameter description of the thermo-viscoelastic linear responses via an order parameter (which may be non-exponential in time). Generalizations to other cases of thermodynamic control parameters than temperature and pressure are treated in an Appendix.Comment: Replaces arXiv:cond-mat/040570

    Conventional methods fail to measure cp(omega) of glass-forming liquids

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    The specific heat is frequency dependent in highly viscous liquids. By solving the full one-dimensional thermo-viscoelastic problem analytically it is shown that, because of thermal expansion and the fact that mechanical stresses relax on the same time scale as the enthalpy relaxes, the plane thermal-wave method does not measure the isobaric frequency-dependent specific heat c_p(omega). This method rather measures a "longitudinal" frequency-dependent specific heat, a quantity defined and detailed here that is in-between c_p(omega) and c_v(omega). This result means that no wide-frequency measurements of c_p(omega) on liquids approaching the calorimetric glass transition exist. We briefly discuss consequences for experiment

    Deregressed EBV as the response variable yield more reliable genomic predictions than traditional EBV in pure-bred pigs

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    <p>Abstract</p> <p>Background</p> <p>Genomic selection can be implemented by a multi-step procedure, which requires a response variable and a statistical method. For pure-bred pigs, it was hypothesised that deregressed estimated breeding values (EBV) with the parent average removed as the response variable generate higher reliabilities of genomic breeding values than EBV, and that the normal, thick-tailed and mixture-distribution models yield similar reliabilities.</p> <p>Methods</p> <p>Reliabilities of genomic breeding values were estimated with EBV and deregressed EBV as response variables and under the three statistical methods, genomic BLUP, Bayesian Lasso and MIXTURE. The methods were examined by splitting data into a reference data set of 1375 genotyped animals that were performance tested before October 2008, and 536 genotyped validation animals that were performance tested after October 2008. The traits examined were daily gain and feed conversion ratio.</p> <p>Results</p> <p>Using deregressed EBV as the response variable yielded 18 to 39% higher reliabilities of the genomic breeding values than using EBV as the response variable. For daily gain, the increase in reliability due to deregression was significant and approximately 35%, whereas for feed conversion ratio it ranged between 18 and 39% and was significant only when MIXTURE was used. Genomic BLUP, Bayesian Lasso and MIXTURE had similar reliabilities.</p> <p>Conclusions</p> <p>Deregressed EBV is the preferred response variable, whereas the choice of statistical method is less critical for pure-bred pigs. The increase of 18 to 39% in reliability is worthwhile, since the reliabilities of the genomic breeding values directly affect the returns from genomic selection.</p

    Great Salt Lake Data and Insights Summary: A Synthesized Resource Document for the 2024 General Legislative Session

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    In 2023, Great Salt Lake rose from the record-low elevation reached in 2022, aided by record-high winter snowfall and the adaptive management berm. Economic activity, public health, and the lake\u27s ecosystems continue to be adversely impacted by low water levels. This summary synthesizes essential data and insights so decision-makers have the information they need to improve water management, increase water deliveries to the lake, mitigate adverse impacts, and recover the lake to a healthy range

    Great Salt Lake Data and Insights Summary: A Synthesized Resource Document for the 2025 General Legislative Session

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    In 2024, Great Salt Lake continued to rise from the record-low elevation reached in 2022, aided by two years of above-average precipitation and the adaptive management berm. Economic activity, public health, and the lake\u27s ecosystems continue to be adversely impacted by low water levels. This summary synthesizes essential data and insights so decision-makers have the information they need to improve water management, increase water deliveries to the lake, mitigate adverse impacts, and recover the lake to a healthy range

    The ASH1 HOMOLOG 2 (ASHH2) Histone H3 Methyltransferase Is Required for Ovule and Anther Development in Arabidopsis

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    BACKGROUND:SET-domain proteins are histone lysine (K) methyltransferases (HMTase) implicated in defining transcriptionally permissive or repressive chromatin. The Arabidopsis ASH1 HOMOLOG 2 (ASHH2) protein (also called SDG8, EFS and CCR1) has been suggested to methylate H3K4 and/or H3K36 and is similar to Drosophila ASH1, a positive maintainer of gene expression, and yeast Set2, a H3K36 HMTase. Mutation of the ASHH2 gene has pleiotropic developmental effects. Here we focus on the role of ASHH2 in plant reproduction. METHODOLOGY/PRINCIPAL FINDINGS:A slightly reduced transmission of the ashh2 allele in reciprocal crosses implied involvement in gametogenesis or gamete function. However, the main requirement of ASHH2 is sporophytic. On the female side, close to 80% of mature ovules lack embryo sac. On the male side, anthers frequently develop without pollen sacs or with specific defects in the tapetum layer, resulting in reduction in the number of functional pollen per anther by up to approximately 90%. In consistence with the phenotypic findings, an ASHH2 promoter-reporter gene was expressed at the site of megaspore mother cell formation as well as tapetum layers and pollen. ashh2 mutations also result in homeotic changes in floral organ identity. Transcriptional profiling identified more than 300 up-regulated and 600 down-regulated genes in ashh2 mutant inflorescences, whereof the latter included genes involved in determination of floral organ identity, embryo sac and anther/pollen development. This was confirmed by real-time PCR. In the chromatin of such genes (AP1, AtDMC1 and MYB99) we observed a reduction of H3K36 trimethylation (me3), but not H3K4me3 or H3K36me2. CONCLUSIONS/SIGNIFICANCE:The severe distortion of reproductive organ development in ashh2 mutants, argues that ASHH2 is required for the correct expression of genes essential to reproductive development. The reduction in the ashh2 mutant of H3K36me3 on down-regulated genes relevant to the observed defects, implicates ASHH2 in regulation of gene expression via H3K36 trimethylation in chromatin of Arabidopsis inflorescences
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