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Multicellular Systems Biology: Quantifying Cellular Patterning and Function in Plant Organs Using Network Science

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Molecular Plant 2019年第6期12卷 731-742页

作者： george W.Bassel School of Biosciences University of Birmingham Birmingham B15 2TT UK

Organ function is at least partially shaped and constrained by the organization of their constituent cells. Extensive investigation has revealed mechanisms explaining how these patterns are generated, with less being known about their functional relevance. In this paper, a methodology to discretize and quantitatively analyze cellular patterning is described. By performing global organ-scale cellular interaction mapping, the organization of cells can be extracted and analyzed using network science. This provides a means to take the developmental analysis of cellular organization in complex organisms beyond qualitative descriptions and provides data-driven approaches to inferring cellular function. The bridging of a structure- function relationship in hypocotyl epidermal cell patterning through global topological analysis provides support for this approach. The analysis of cellular topologies from patterning mutants further enables the contribution of gene activity toward the organizational properties of tissues to be linked, bridging molecular and tissue scales. This systems-based approach to investigate multicellular complexity paves the way to uncovering the principles of complex organ design and achieving predictive genotypephenotype mapping.

关键词： organ network connectivity transport tissue topology connectome

The crossed phrenic phenomenon

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Neural Regeneration Research 2017年第6期12卷 845-864页

作者： Michael george Zaki Ghali Department of Neurobiology & Anatomy Drexel University College of Medicine

The cervical spine is the most common site of traumatic vertebral column injuries. Respiratory insufficiency constitutes a significant proportion of the morbidity burden and is the most common cause of mortality in these patients. In seeking to enhance our capacity to treat specifically the respiratory dysfunction following spinal cord injury, investigators have studied the “crossed phrenic phenomenon”, wherein contraction of a hemidiaphragm paralyzed by a complete hemisection of the ipsilateral cervical spinal cord above the phrenic nucleus can be induced by respiratory stressors and recovers spontaneously over time. Strengthening of latent contralateral projections to the phrenic nucleus and sprouting of new descending axons have been proposed as mechanisms contributing to the observed recovery. We have recently demonstrated recovery of spontaneous crossed phrenic activity occurring over minutes to hours in C_1-hemisected unanesthetized decerebrate rats. The specific neurochemical and molecular pathways underlying crossed phrenic activity following injury require further clarification. A thorough understanding of these is necessary in order to develop targeted therapies for respiratory neurorehabilitation following spinal trauma. Animal studies provide preliminary evidence for the utility of neuropharmacological manipulation of serotonergic and adenosinergic pathways, nerve grafts, olfactory ensheathing cells, intraspinal microstimulation and a possible role for dorsal rhizotomy in recovering phrenic activity following spinal cord injury.

关键词： crossed traumatic spontaneously olfactory diaphragm descending vertebral spine sprouting minutes

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The Villafranchian carnivoran guild of Greece:implications for the fauna,biochronology and paleoecology

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Integrative Zoology 2014年第4期9卷 444-460页

作者： george D.KOUFOS Department of Geology Aristotle University of ThessalonikiThessalonikiGreece

Knowledge on the Villafranchian faunas of Greece was limited for a long time,but over the past 3 decades several new fossiliferous sites have been discovered and new material has been *** carnivores constitute a remarkable part of this material and their study has provided useful information for the taxonomy,chronology and *** Villafranchian carnivoran guild includes numerous taxa belonging to various *** of them are interesting as they are differentiated from the other Eurasian *** cover the entire Villafranchian but the mass is known from the Middle to the Epi-Villafranchian(EVC).Despite the discontinuous data,they provide useful biochronological *** coexistence of Pliocrocuta perrieri and Pachycrocuta brevirostris in the locality of Gerakarou 1 is strong evidence for the Middle Villafranchian(MVC)/Late Villafranchian(LVC)*** composition of the Villafranchian carnivores suggests that the canids predominate,while the felids,hyenids and mustelids are well represented;the ursids are represented by a single taxon,the well-known Ursus etruscus,which seems to be common during the entire *** carnivoran guild structure and the multivariate analysis of the Greek Villafranchian carnivoran assemblages(MVC,LVC and EVC)in comparison with modern assembalges from open and closed environments indicate a relatively open landscape,which is in agreement with previous results for the Villafranchian of *** the EVC there is a faunal renewal that is related to a more open and dry environment,like savannah bushland/grassland.

关键词： biochronology carnivore Greece paleoecology Villafranchian

Capital injections with negative surplus and delays: models and analysis

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Control Theory and Technology 2014年第2期12卷 163-172页

作者： Zhuo JIN george YIN Centre for Actuarial Studies Department of Economics The University of Melbourne VIC 3010 Australia Department of Mathematics Wayne State University Detroit Michigan 48202 U.S.A.

This work develops a new model to deal with the scenario that some companies can still run business even the surplus falls below zero temporarily. With such a scenario in mind, we allow the surplus process to continue in this negative-surplus period, during which capital injections will be ordered to assist in the stabilization of financial structure, until the financial status becomes severe enough to file bankruptcy. The capital injections will be modeled as impulse controls. By introducing the capital injections with time delays, optimal dividend payment and capital injection policies are considered. Using the dynamic programming approach, the value function obeys a quasi-variational inequality. With delays in capital injections, the company will be exposed to the risk of bankruptcy during the delay period. In addition, the optimal dividend payment and capital injection strategies should balance the expected cost of the possible capital injections and the time value of the delay periods. This gives rise to a stochastic control problem with mixed singular and delayed impulse controls. Under general assumptions, the lower capital injection barrier is determined, where bankruptcy occurs. The closed-form solution to the value function and corresponding optimal policies are obtained.

关键词： Stochastic control Capital injection Dividend policy Delayed impulse control Singular contro

Gravitational wave research using pulsar timing arrays

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National Science Review 2017年第5期4卷 707-717页

作者： george Hobbs Shi Dai Australia Telescope National Facility CSIRO

A pulsar timing array(PTA) refers to a program of regular, high-precision timing observations of a widely distributed array of millisecond pulsars. Here we review the status of the three primary PTA projects and the joint International Pulsar Timing Array project. We discuss current results related to ultra-low-frequency gravitational wave searches and highlight opportunities for the near future.

关键词： pulsars gravitational waves radio astronomy

Time derivative of earthquake acceleration

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Earthquake Engineering and Engineering Vibration 2005年第1期4卷 1-16页

作者： george C. Lee Multidisciplinary Center for Earthquake Engineering Research University at Buffalo Buffalo NY 14261-0025 USAProfessor

Unlike acceleration, velocity, and displacement, the time derivative ofacceleration (TDoA) of ground motion has not been extensively studied. In this paper, the basiccharacteristics of TDoA are evaluated based on records from the 1999 Chi-Chi, earthquake (Mw 7.6)and one of its aftershocks (Mw 6.2). It is found that the maximum TDoA at a free-field station wasover 31,200 cm/s3 (31.8 g/s); and the duration of 'strong' TDoA, between the first and the last timepoints exceeding 2,000 cm/s3 (2 g/s), was almost one minute near the epicenter area. Since groundTDoA sensors are not commonly available, the time series are calculated by direct numericaldifferentiation of acceleration time series. Relative error analysis shows that the error isnon-transitive and total error is within 4%. The density function of TDoA amplitude, frequencycontent and spatial distribution of peak ground jerk (PGJ) are evaluated. The study also includesexamination of some TDoA responses from a seven-story building and comparison of ground TDoA withthe limit TDoA used in the transportation industry for ride comfort. Some potential impacts of TDoAon humans have also been reviewed.

关键词： time derivation of acceleration peak ground jerk acceleration time series earthquake ground motion earthquake effect on human activities

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Partitions with Initial Repetitions

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Acta Mathematica Sinica,English Series 2009年第9期25卷 1437-1442页

作者： george E.ANDREWS The Pennsylvania State University University Park

A variety of interesting connections with modular forms, mock theta functions and Rogers- Ramanujan type identities arise in consideration of partitions in which the smaller integers are repeated as summands more often than the larger summands. In particular, this concept leads to new interpretations of the Rogers Selberg identities and Bailey＇s modulus 9 identities.

关键词： partitions without gaps initial k-repetitions Glaisher's theorem Rogers-Selberg identities Bailey's modulus 9 identities

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Habitat fragmentation, vole population fluctuations, and the ROMPA hypothesis: An experimental test using model landscapes

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Integrative Zoology 2016年第6期11卷 469-482页

作者： george O.BATZLI Department of Animal Biology University of IllinoisChampaignIllinoisUSA

Increased habitat fragmentation leads to smaller size of habitat patches and to greater distance between patch*** ROMPA hypothesis(ratio of optimal to marginal patch area)uniquely links vole population fluctuations to the composition of the *** states that as ROMPA decreases(fragmentation increases),vole population fluctuations will increase(including the tendency to display multi-annual cycles in abundance)because decreased proportions of optimal habitat result in greater population declines and longer recovery time after a harsh *** date,only comparative observations in the field have supported the *** paper reports the results of the first experimental test.I used prairie voles,Microtus ochrogaster,and mowed grassland to create model landscapes with 3 levels of ROMPA(high with 25%mowed,medium with 50%mowed and low with 75%mowed).As ROMPA decreased,distances between patches of favorable habitat(high cover)increased owing to a greater proportion of unfavorable(mowed)*** from the first year with intensive live trapping indicated that the preconditions for operation of the hypothesis existed(inversely density dependent emigration and,as ROMPA decreased,increased per capita mortality and decreased per capita movement between optimal patches).Nevertheless,contrary to the prediction of the hypothesis that populations in landscapes with high ROMPA should have the lowest variability,5 years of trapping indicated that variability was lowest with medium *** design of field experiments may never be perfect,but these results indicate that the ROMPA hypothesis needs further rigorous testing.

关键词： experimental landscapes habitat fragmentation Microtus ochrogaster ROMPA hypothesis vole population fluctuations

Two uncommon manifestations of leptospirosis:Sweet's syndrome and central nervous system vasculitis

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Asian Pacific Journal of Tropical Medicine 2011年第1期4卷 83-84页

作者： Peter george Department of Medicine Yenepoya Medical CollegeMangaloreS India

To leptospirosis is the commonest spirocheatal infection in the tropical and temperate countries of Indian sub-continent and Africa and the most common zoonosis *** protean manifestation of this infectious disease is a challenge for practising clinicians across the world. In poor developing countries,at most clinical suspicion it is essential in the diagnosis of this *** this report,we are able to document two uncommon manifestations of leptospirosis, namely Sweet’s syndrome and central nervous system vasculitis.

关键词： Leptospirosis Sweet’s syndrome Central nervous system vasculitis