74 research outputs found
Thermodynamics of Accelerating Black Holes
We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermo- dynamics, with the usual identification of entropy proportional to the area of the event horizon — even though the event horizon contains a conical singularity. We show how to generalise this result, formulating thermodynamics for black holes with varying conical deficits. We derive a new potential for the varying tension defects: the thermodynamic length, both for accelerating and static black holes. We discuss possible physical processes in which the tension of a string ending on a black hole might vary, and also map out the thermodynamic phase space of accelerating black holes and explore their critical phenomena. We then revisit the critical limit in which asymptotically-AdS black holes develop maximal conical deficits, first for a stationary rotating black hole, and then for an accelerated black hole, by taking various upper bounds for the parameters in the spacetimes presented. We explore the thermodynamics of these geometries and evaluate the reverse isoperimetric inequal- ity, and argue that the ultra-spinning black hole only violates this condition when it is nonaccelerating. Finally, we return to some of our earlier findings and adjust them in light of new results; a new expression for the mass is obtained by computing the dual stress-energy tensor for the spacetime and finding that it corresponds to a relativistic fluid with a nontrivial viscous shear tensor. We compare the holographic computation with the method of conformal completion showing it yields the same result for the mass
Wheat functional genomics and engineering crop improvement
Genetic mapping and determination of the organization of the wheat genome are changing the wheat-breeding process. New initiatives to analyze the expressed portion of the wheat genome and structural analysis of the genomes of Arabidopsis and rice are increasing our knowledge of the genes that are linked to key agronomically important traits
Black hole thermodynamics with conical defects
Recently we have shown [1] how to formulate a thermodynamic first law for a single (charged) accelerated black hole in AdS space by fixing the conical deficit angles present in the spacetime. Here we show how to generalise this result, formulating thermodynamics for black holes with varying conical deficits. We derive a new potential for the varying tension defects: the thermodynamic length, both for accelerating and static black holes. We discuss possible physical processes in which the tension of a string ending on a black hole might vary, and also map out the thermodynamic phase space of accelerating black holes and explore their critical phenomena
Shifting the limits in wheat research and breeding using a fully annotated reference genome
Introduction:
Wheat (Triticum aestivum L.) is the most widely cultivated crop on Earth, contributing about a fifth of the total calories consumed by humans. Consequently, wheat yields and production affect the global economy, and failed harvests can lead to social unrest. Breeders continuously strive to develop improved varieties by fine-tuning genetically complex yield and end-use quality parameters while maintaining stable yields and adapting the crop to regionally specific biotic and abiotic stresses.
Rationale:
Breeding efforts are limited by insufficient knowledge and understanding of wheat biology and the molecular basis of central agronomic traits. To meet the demands of human population growth, there is an urgent need for wheat research and breeding to accelerate genetic gain as well as to increase and protect wheat yield and quality traits. In other plant and animal species, access to a fully annotated and ordered genome sequence, including regulatory sequences and genome-diversity information, has promoted the development of systematic and more time-efficient approaches for the selection and understanding of important traits. Wheat has lagged behind, primarily owing to the challenges of assembling a genome that is more than five times as large as the human genome, polyploid, and complex, containing more than 85% repetitive DNA. To provide a foundation for improvement through molecular breeding, in 2005, the International Wheat Genome Sequencing Consortium set out to deliver a high-quality annotated reference genome sequence of bread wheat.
Results:
An annotated reference sequence representing the hexaploid bread wheat genome in the form of 21 chromosome-like sequence assemblies has now been delivered, giving access to 107,891 high-confidence genes, including their genomic context of regulatory sequences. This assembly enabled the discovery of tissue- and developmental stage–related gene coexpression networks using a transcriptome atlas representing all stages of wheat development. The dynamics of change in complex gene families involved in environmental adaptation and end-use quality were revealed at subgenome resolution and contextualized to known agronomic single-gene or quantitative trait loci. Aspects of the future value of the annotated assembly for molecular breeding and research were exemplarily illustrated by resolving the genetic basis of a quantitative trait locus conferring resistance to abiotic stress and insect damage as well as by serving as the basis for genome editing of the flowering-time trait.
Conclusion:
This annotated reference sequence of wheat is a resource that can now drive disruptive innovation in wheat improvement, as this community resource establishes the foundation for accelerating wheat research and application through improved understanding of wheat biology and genomics-assisted breeding. Importantly, the bioinformatics capacity developed for model-organism genomes will facilitate a better understanding of the wheat genome as a result of the high-quality chromosome-based genome assembly. By necessity, breeders work with the genome at the whole chromosome level, as each new cross involves the modification of genome-wide gene networks that control the expression of complex traits such as yield. With the annotated and ordered reference genome sequence in place, researchers and breeders can now easily access sequence-level information to precisely define the necessary changes in the genomes for breeding programs. This will be realized through the implementation of new DNA marker platforms and targeted breeding technologies, including genome editing
Supplementary File for Capturing wheat phenotypes at the genome level
Supplementary S1: Yield and related traits in bread wheat.
Table S1: Examples of genomic regions, candidate and cloned genes for yield and related traits in bread wheat.
Supplementary S2: Drought tolerance.
Table S2: Examples of genomic regions and candidate genes for drought tolerance.
Supplementary S3: Heat tolerance.
Table S3. Examples of genomic regions and candidate genes for heat tolerance.
Supplementary S4: salinity tolerance in bread wheat.
Table S4. Examples of genomic regions and candidate genes for salinity tolerance in bread wheat.
Supplementary S5: Frost tolerance.
Supplementary S6: Disease resistance.
Table S5. Examples of genomic regions, candidate and cloned genes mapped for disease resistance in wheat species.
Supplementary S7 insect and mite resistance.
Table S6. Examples of genomic regions and candidate genes mapped for insect and mite resistance.
Supplementary S8: Quality traits.
Table S7. Examples of genomic regions, candidate and cloned genes for quality traits.Recent technological advances in next-generation sequencing (NGS) technologies have dramatically reduced the cost of DNA sequencing, allowing species with large and complex genomes to be sequenced. Although bread wheat (Triticum aestivum L.) is one of the world’s most important food crops, efficient exploitation of molecular marker-assisted breeding approaches has lagged behind that achieved in other crop species, due to its large polyploid genome. However, an international public–private effort spanning 9 years reported over 65% draft genome of bread wheat in 2014, and finally, after more than a decade culminated in the release of a gold-standard, fully annotated reference wheat-genome assembly in 2018. Shortly thereafter, in 2020, the genome of assemblies of additional 15 global wheat accessions was released. As a result, wheat has now entered into the pan-genomic era, where basic resources can be efficiently exploited. Wheat genotyping with a few hundred markers has been replaced by genotyping arrays, capable of characterizing hundreds of wheat lines, using thousands of markers, providing fast, relatively inexpensive, and reliable data for exploitation in wheat breeding. These advances have opened up new opportunities for marker-assisted selection (MAS) and genomic selection (GS) in wheat. Herein, we review the advances and perspectives in wheat genetics and genomics, with a focus on key traits, including grain yield, yield-related traits, end-use quality, and resistance to biotic and abiotic stresses. We also focus on reported candidate genes cloned and linked to traits of interest. Furthermore, we report on the improvement in the aforementioned quantitative traits, through the use of (i) clustered regularly interspaced short-palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated gene-editing and (ii) positional cloning methods, and of genomic selection. Finally, we examine the utilization of genomics for the next-generation wheat breeding, providing a practical example of using in silico bioinformatics tools that are based on the wheat reference-genome sequence.Peer reviewe
Psychophysiology of type A behavior pattern: A critical analysis
Based on an analysis of 45 studies recently reported in the literature and data from a psychophysiological investigation, the hypothesized physiological mechanisms underlying Type A behavior and the methods used to determine Type A behavior (e.g., Structured Interview, SI, and the Jenkins Activity Survey, JAS) are tested. After determining behavior type with both the SI and JAS, subjects (N = 58 physical-education students) participated in a laboratory/field experiment with two replications consisting of the following conditions: (1) rest, (2) mental arithmetic, (3) reaction time test, (4) preparing and giving a speech, (5) Cold Pressor Test, (6) bicycle ergometric exercise, and (7) 1000 m run. Blood pressure, heart rate, stroke volume, cardiac output, ventricular ejection time, pulse volume amplitude, pulse transit time, pulse wave velocity, electrodermal activity, respiratory volume, oxygen uptake, and uric catecholamine levels were measured. Results of the analysis of the literature indicate that, with the exception of change scores on systolic blood pressure, mean differences on the physiological measures exhibited by Type A and B men are primarily not significant. The Structured Interview shows only a modest inter-rater reliability. The Jenkins Activity Survey demonstrates relatively low stability upon retest and fails to show sufficient internal consistency. Correlations between these measures are low. No consistent differences on physiological measures could be found in our subjects based on behavior type (according to SI or JAS criteria), although the challenging conditions were selected to elicit Type A behavior. For our data, differences between Types A and B were also not found for systolic blood pressure, regardless of which behavioral assessment method was employed
A moral foundations perspective on CEO political ideology and moral behavior
As an integral component of their value system, CEOs’ political ideology has come to be regarded a major determinant for (ir)responsible behaviors. Yet, prior work remains inconclusive on whether it is a more liberal or a more conservative ideological leaning that leads CEOs to engage in more or less (ir)responsible behavior. We argue that this is, at least partly, due to a reliance on the theory of political ideology as motivated cognition rather than the consideration of ideological differences from the perspective of moral psychology. Integrating moral foundations theory into the upper echelons perspective, we theorize that what distinguishes the (ir)responsibility of liberal versus conservative-leaning CEOs may at times be its nature rather than its degree and depend on individual and contextual characteristics. Correspondingly, we show that higher degrees of liberalism and conservatism induce CEOs to increasingly engage in higher degrees of responsible behavior (CSR). In the domain of irresponsible behavior, we likewise observe comparability in CEOs’ degree of earnings management and demonstrate that liberal and conservative-leaning CEOs’ ways of managing earnings follow their ideological reliance on differential moral foundations. As such, we offer a new vantage on CEOs’ political ideologies and their organizational ramifications in (ir)responsibly laden contexts
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