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Evolutionary and ecological genomics of non-model plants

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Journal of Systematics and Evolution 2011年第1期49卷 17-24页

作者： thomas MITCHELL-OLDS Institute for Genome Sciences and Policy Department of Biology Duke University

Dissecting evolutionary dynamics of ecologically important traits is a long-term challenge for biologists. Attempts to understand natural variation and molecular mechanisms have motivated a move from laboratory model systems to non-model systems in diverse natural environments. Next generation sequencing methods, along with an expansion of genomic resources and tools, have fostered new links between diverse disciplines, including molecular biology, evolution, ecology, and genomics. Great progress has been made in a few non-model wild plants, such as Arabidopsis relatives, monkey flowers, and wild sunflowers. Until recently, the lack of comprehensive genomic information has limited evolutionary and ecological studies to larger QTL (quantitative trait locus) regions rather than single gene resolution, and has hindered recognition of general patterns of natural variation and local adaptation. Further efforts in accumulating genomic data and developing bioinformatic and biostatistical tools are now poised to move this field forward. Integrative national and international collaborations and research communities are needed to facilitate development in the field of evolutionary and ecological genomics.

关键词： candidate genes ecological genomics fitness natural selection population genomics QTL.

Observing quantum coherence from photons scattered in free-space

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Light(Science & Applications) 2021年第7期10卷 1304-1312页

作者： Shihan Sajeed thomas Jennewein Institute for Quantum Computing University of WaterlooWaterlooON N2L 3G1Canada Department of Physics and Astronomy University of WaterlooWaterlooON N2L 3G1Canada

Quantum channels in free-space,an essential prerequisite for fundamental tests of quantum mechanics and quantum technologies in open space,have so far been based on direct line-of-sight because the predominant approaches for photon-encoding,including polarization and spatial modes,are not compatible with randomly scattered *** we demonstrate a novel approach to transfer and recover quantum coherence from scattered,non-line-of-sight photons analyzed in a multimode and imaging interferometer for time-bins,combined with photon detection based on a 8×8 *** observed time-bin visibility for scattered photons remained at a high 95%over a wide scattering angle range of−45^(0) to+45^(0),while the individual pixels in the detector array resolve or track an image in its field of view of ca.0.5°.Using our method,we demonstrate the viability of two novel ***,using scattered photons as an indirect channel for quantum communication thereby enabling non-line-of-sight quantum communication with background suppression,and secondly,using the combined arrival time and quantum coherence to enhance the contrast of low-light imaging and laser ranging under high background *** believe our method will instigate new lines for research and development on applying photon coherence from scattered signals to quantum sensing,imaging,and communication in free-space environments.

关键词： scattered quantum photons

An overview of cryptographic primitives for possible use in 5G and beyond

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Science China(Information Sciences) 2020年第12期63卷 5-26页

作者： Jing YANG thomas JOHANSSON Department of Electrical and Information Technology Lund University

This survey overviews the potential use of cryptographic primitives in the fifth-generation mobile communications system(aka 5G) and beyond. It discusses the new security challenges that come with 5G and presents the upcoming security architecture. It shows the use of current cryptographic algorithms and discusses new algorithms or modifications of existing ones, that can be relevant. It also discusses the need for lightweight algorithms to meet the new use cases as well as the general demand for algorithms secure even when large quantum computers are available.

关键词： 5G cryptographic primitives lightweight cryptography post-quantum cryptography

The reliability of age measurements for Young Stellar Objects from Hertzsprung-Russell or color-magnitude diagrams

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Research in Astronomy and Astrophysics 2012年第1期12卷 1-25页

作者： thomas Preibisch Universitts-Sternwarte Mnchen Ludwig-Maximilians-Universitt

The possibility to estimate ages and masses of Young Stellar Objects （YSOs） from their location in the Hertzsprnng-Russell diagram （HRD） or a color- magnitude diagram provides a very important tool for the investigation of fundamen- tal questions related to the processes of star formation and early stellar evolution. Age estimates are essential for studies of the temporal evolution of circumstellar material around YSOs and the conditions for planet formation. The characterization of the age distribution of the YSOs in a star forming region allows researchers to reconstruct the star formation history and provides important information on the fundamental ques- tion of whether star formation is a slow or a fast process. However, the reliability of these age measurements and the ability to detect possible age spreads in the stellar population of star forming regions are fundamentally limited by several factors. The variability of YSOs, unresolved binary components, and uncertainties in the calibra- tions of the stellar parameters cause uncertainties in the derived luminosities that are usually much larger than the typical photometry errors. Furthermore, the pre-main se- quence evolution track of a YSO depends to some degree on the initial conditions and the details of its individual accretion history. I discuss how these observational and model uncertainties affect the derived isochronal ages, and demonstrate how neglect- ing or underestimating these uncertainties can easily lead to severe misinterpretations, gross overestimates of the age spread, and ill-based conclusions about the star for- marion history. These effects are illustrated by means of Monte-Carlo simulations of observed star clusters with realistic observational uncertainties. The most important points are as follows. First, the observed scatter in the HRD must not be confused with a genuine age spread, but is always just an upper limit to the true age spread. Second, histograms of isochronal ages natural

关键词： stars: ages -- stars: pre-main sequence -- stars: formation --Hertzsprung-Russell diagram

On Markov Chains Induced by Partitioned Transition Probability Matrices

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Acta Mathematica Sinica,English Series 2011年第3期27卷 441-476页

作者： thomas KAIJSER Department of Mathematics and Information Coding Group Linkoping University S-581 83 LinkSping Sweden

Let S be a denumerable state space and let P be a transition probability matrix on S. If a denumerable set M of nonnegative matrices is such that the sum of the matrices is equal to P, then we call M a partition of P. Let K denote the set of probability vectors on S. With every partition M of P we can associate a transition probability function PM on K defined in such a way that if p ∈ K and M ∈M are such that ｜｜pM｜｜〉 0, then, with probability ｜｜pM｜｜ the vector p is transferred to the vector pM/｜｜pM｜｜. Here ｜｜·｜｜ denotes the/1-norm. In this paper we investigate the convergence in distribution for Markov chains generated by transition probability functions induced by partitions of transition probability matrices. The main motivation for this investigation is the application of the convergence results obtained to filtering processes of partially observed Markov chains with denumerable state space.

关键词： Markov chains on nonlocally compact spaces filtering processes hidden Markov chains Kantorovich metric barycenter

Phenylpropanoid Biosynthesis

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Molecular Plant 2010年第1期3卷 2-20页

作者： thomas Vogt Leibniz-lnstitute of Plant Biochemistry Department of Secondary Metabolism Weinberg 3 D-06120 Halle (Saale) Germany

The general phenylpropanoid metabolism generates an enormous array of secondary metabolites based on the few intermediates of the shikimate pathway as the core unit. The resulting hydroxycinnamic acids and esters are am- plified in several cascades by a combination of reductases, oxygenases, and transferases to result in an organ and devel- opmentally specific pattern of metabolites, characteristic for each plant species. During the last decade, methodology driven targeted and non-targeted approaches in several plant species have enabled the identification of the participating enzymes of this complex biosynthetic machinery, and revealed numerous genes, enzymes, and metabolites essential for regulation and compartmentation. Considerable success in structural and computational biology, combined with the an- alytical sensitivity to detect even trace compounds and smallest changes in the metabolite, transcript, or enzyme pattern, has facilitated progress towards a comprehensive view of the plant response to its biotic and abiotic environment. Trans- genic approaches have been used to reveal insights into an apparently redundant gene and enzyme pattern required for functional integrity and plasticity of the various phenylpropanoid biosynthetic pathways. Nevertheless, the function and impact of all members of a gene family remain to be completely established. This review aims to give an update on the various facets of the general phenylpropanoid pathway, which is not only restricted to common lignin or flavonoid biosynthesis, but feeds into a variety of other aromatic metabolites like coumarins, phenolic volatiles, or hydrolyzable tannins.

关键词： Phenylpropanoid biosynthetic pathway flavonoid anthocyanin tannin coumarin volatiles lignin.

What would a US green hydrogen energy economy look like?

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Clean Energy 2023年第5期7卷 1148-1172页

作者： thomas Tonon Independent researcher Ph.D.Aerospace and Mechanical SciencesPrinceton University1971.11 Bolfmar AvenuePrinceton JunctionNJ 08550USA

Detailed description is given for a hypothetical US hydrogen economy with solar and wind energy supplying virtually all current energy needs and with electrolytic hydrogen the energy carrier and storage *** fuels provide nonfuel products(plastics,chemicals,cement and asphalt).Only current technologies are considered and hydrogen storage accommodates generation intermit-tency and variability,using pit storage of high-pressure vessels in open air,yielding daily storage round-trip energy installation costs of 722 and 538$/kWh for electric and thermal,respectively;and for power,2351 and 2240$/kW for electric and thermal,*** long-duration storage,the costs are 94.1 and 23.8$/kWh and 937 and 845$/kW,*** energy generation 20%over baseline accommodates low-season generation,obviates much required storage and ensures that reserves are topped off;96%of US 2022 total energy consumption is provided *** the default scenario(demand energy portions:half photovoltaic,quarter on-shore wind and quarter offshore wind),the surface area for the farms(including offshore surface)requires~4.6%of the US 48-state land *** 350 pit storage sites provide both daily and long-duration storage,with the latter accounting for complete loss of generation for 4 days over a quarter of the *** pipelines and a renewed electric grid transmit and distribute *** installation cost of the public infrastructure is~$27.8 trillion for the default *** scenarios show significant in-frastructure and cost savings when batteries are used for transportation and/or utility storage,provided current insufficiencies can be ***,cost levels in money,surface and infrastructure are within existing levels already achieved in historical events and modern living.

关键词： hydrogen economy renewable energy hydrogen storage hydrogen pipelines sustainable net zero

Injector Quantum Dot Molecule Infrared Photodetector:A Concept for Efficient Carrier Injection

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Nano-Micro Letters 2011年第2期3卷 121-128页

作者： thomas Gebhard thomas Gebhard Photonics InstituteVienna University of Technology

Quantum dot infrared photodetectors are expected to be a competitive technology at high oper ation temperatures in the long and very long wavelength infrared spectral *** the fact that they already achieved notable success,the performance suffers from the thermionic emission of electrons from the quantum dots at elevated temperatures resulting in a decreasing *** order to provide an efficient carrier injection at high temperatures,quantum dot infrared photodetectors can be separated into two parts:an injection part and a detection part,so that each part can be separately *** order to integrate such functionality into a device,a new class of quantum dot infrared photodetectors using quantum dot molecules will be *** addition to a general discussion simulation results suggest a possibility to realize such a device.

关键词： Quantum dot infrared photodetector Injection Quantum dot molecule High temperature operation Responsivity

Recent result from the A2 real photon facility at MAMI

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Chinese Physics C 2009年第12期33卷 1120-1126页

作者： Andreas thomas Institut fr Kernphysik University Mainz J.-J. Becherweg 45 D-55099 Mainz Germany

The upgraded MAMI C accelerator is delivering electrons with an energy of 1558 MeV routinely. The A2 collaboration is doing experiments with energy marked polarised real photons produced via ＂Bremsstrahlung＂. Recent results from the GDH-experiment using a longitudinal polarised frozen spin target in combination with the DAPHNE detector and from the Crystal Ball experiment at MAMI are presented.

关键词： photonuclear reactions polarization phenomena in reactions polarized and other targets leptoninduced reactions