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International Journal of Agricultural and Biological Engineering 2014年第4期7卷 86-98页

作者： Srinivas Reddy Kamireddy Evguenii I.Kozliak Melvin tucker Yun Ji Department of Chemical Engineering University of North DakotaGrand ForksND 58202USA Department of Chemistry University of North DakotaGrand ForksND 58202USA National Bioenergy Center National Renewable Energy LaboratoryGoldenCO 80401USA

A kinetic study of acid pretreatment was conducted for sorghum non-brown mid rib(SNBMR)(Sorghum bicolor L Moench),sorghum-brown mid rib(SBMR),sunn hemp(Crotalaria juncea L)and kenaf(Gossypiumhirsutum L),focusing on rates of xylose monomer and furfural *** kinetics was investigated using two independent variables,reaction temperature(150°C and 160°C)and acid concentration(1 and 2 wt%),with a constant dry biomass loading of 10 wt%and a treatment time up to 20 min while sampling the mixture every 2 *** experimental data were fitted using a two-step kinetic model based on irreversible pseudo first order kinetics at each *** kinetic orders on the acid concentration,ranging from 0.2 to>3,were observed for both xylose and furfural formation,the values depending on the *** crystallinity index of raw biomass was shown to be a major factor influencing the rate of both xylose and furfural formation.A positive correlation was observed between the activation energy and biomass crystallinity index for xylose formation.

关键词： acid pretreatment sunn hemp sorghum brown-mid rib(BMR) sorghum non brown-mid rib(SNBMR) kenaf reaction kinetics activation energy reaction order

Changshanian Maximum Flooding Event in China and Its Global Correlation

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Acta Geologica Sinica(English Edition) 1996年第4期70卷 341-355,451页

作者： M.E.tucker U niverSity of Durhnm.U.K.

Various orders of condensed sections are recognized in the Cambrian of North China Carbonate Platform. Study of comparative sedimentology proves that CS4-CS5 in the Changshanian age is the maximum sea flooding sediments in the Cambrian, regardless of the distribution, thickness, internal structure of the condensed section series and K2O abundance. It is a two-layered composite condensed section series, characterized by the enrichment of such elements as K, P, Mn, Ti, Co, V, Cr, Cu, Zr, Ni, Li, Th, La, Ce, Nd, Dy, Y, Sc and Be. The Changshanian maximum flooding event can be correlated on a global scale, and the corresponding sedimentary records are discovered in 26 intercontinental sections in N. Europe, N. America, and Tarim and the Yangtze Platform of China. Through detailed sedimentological research, meter-scale cycle analysis and Fischer plots, it is concluded that the Changshanian maximum flooding was a composite effect of the second-order eustacy superimposed by the third-and fourth-order eustacy, which lasted for 1.2-3 Ma. An intercontinental model of the Changshanian maximum flooding is proposed at the end of this paper.

关键词： Changshanian age maximum flooding event condensed section global correlation Cambrian

Milankovitch-driven cycles in the Precambrian of China:The Wumishan Formation

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Journal of Palaeogeography 2013年第4期2卷 369-389页

作者： Mei Mingxiang Maurice E. tucker State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences (Beijing) Department of Earth Sciences University of Durham

Carbonate strata of the Mesoproterozoic Wumishan Formation in the Jixian area near Tianjin are ~3300 m thick and were deposited over some 100 million years(from ~1310±20 Ma to ~1207±10 Ma).Metre-scale cycles(parasequences) dominate the *** are generally of the peritidal carbonate type,and mostly show an approximately symmetrical lithofacies succession with thick stromatolite biostromes and small thromboliteoncolite bioherms constituting the central part and tidal-flat dolomites forming the upper and lower ***-supratidal dolomitic shales with palaeosol caps make up the topmost *** boundaries of the Wumishan cycles are typically exposure surfaces,and there is abundant evidence for fresh-water *** 1:4 stacking patterns indicate that the individual Wumishan cycles are sixthorder parasequences,with 4 parasequences constituting one fifth-order parasequence ***,5-8 beds or couplets,can be discerned in some of the *** regular vertical stacking pattern of beds within the sixth-order parasequences,forming the fifth-order parasequence sets,are interpreted as the result of environmental fluctuations controlled by Milankovitch rhythms,namely the superimposition of precession,and short and *** widespread 1:4 stacking pattern in the cyclic succession,as well as the local 1:5-8 stacking patterns of the beds within the cycles,suggest that the Milankovitch rhythms had similar ratios in the Mesoproterozoic as in the *** on the cycle stacking patterns,26 thirdorder sequences can be distinguished and these group into 6 second-order,transgressiveregressive megasequences(or sequence sets),all reflecting a composite,hierarchical succession of relative sea-level changes.

关键词： peritidal carbonate cycles Milankovitch rhythms Wumishan Formation Mesoproterozoic Tianjin North China

Facies-succession and architecture of the third-order sequences and their stratigraphic framework of the Devonian in Yunnan-Guizhou-Guangxi area,South China

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Journal of Palaeogeography 2013年第1期2卷 93-108页

作者： Mei Mingxiang Maurice E.tucker School of Earth Science and Mineral Resources China University of Geosciences (Beijing) Department of Geological Sciences University of Durham

The Caledonian orogeny at the end of the Silurian resulted in great changes in the palaeogeography in the Yunnan-Guizhou-Guangxi area of South China; the continental area of the Early Paleozoic evolved into the extensive Dian-Qian-Gui Sea in the Late Paleo-zoic. Early in the Devonian, as a result of a major transgression, seawater encroached gradually from the south to the north and clastic facies were deposited. Carbonate deposition was then established in the Yunnan-Guizhou-Guangxi area, with a palaeogeography marked by attached platforms, isolated platforms and narrow basins. As a result of the Ziyun movement towards the end of the Devonian, the Upper Devonian strata are regressive and thin out from the open-sea to the land areas. A study of the nature and distribution of sedimentary facies in space and time recognises 13 third-order sequences in the Devonian strata in Yunnan-Guizhou-Guangxi area, and these form two second-order sequences. The strata of the Lower Devonian comprise 5 third-order sequences (SQ1 to SQ5 ), which are dominated by transgressive clastics. 4 third-order sequences (SQ6 to SQ9 ) in the Middle Devonian are characterized by alternations of transgressive clastics and highstand carbonates. In the Upper Devonian, carbonates constitute 4 third-order sequences (SQ10 to SQ13 ), which are generally marked by the transgressive limestones and highstand dolomites. On the basis of earlier biostratigraphic studies, sea-level changes represented by the third-order sequences with their different facies successions are explored, and the sequence stratigraphic framework is established. There-fore, the Devonian strata in the study area provide an example for further understanding of depositional trends within the sequence-stratigraphic framework.

关键词： sequence stratigraphy Devonian Yunnan-Guizhou-Guangxi area South China

The importance of large-diameter trees to the creation of snag and deadwood biomass

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Ecological Processes 2021年第1期10卷 380-393页

作者： James A.Lutz Soren Struckman Sara J.Germain tucker J.Furniss Department of Wildland Resources S.J.and Jessie E.Quinney College of Natural ResourcesUtah State University5230 Old Main HillLoganUT 84322-5230USA

Background:Baseline levels of tree mortality can,over time,contribute to high snag densities and high levels of deadwood(down woody debris)if fire is infrequent and decomposition is *** can be important for tree recruitment,and it plays a major role in terrestrial carbon cycling,but deadwood is rarely examined in a spatially explicit ***:Between 2011 and 2019,we annually tracked all trees and snags≥1 cm in diameter and mapped all pieces of deadwood≥10 cm diameter and≥1 m in length in 25.6 ha of Tsuga heterophylla/Pseudotsuga menziesii *** analyzed the amount,biomass,and spatial distribution of deadwood,and we assessed how various causes of mortality that contributed uniquely to deadwood ***:Compared to aboveground woody live biomass of 481 Mg ha^(−1)(from trees≥10 cm diameter),snag biomass was 74 Mg ha^(−1) and deadwood biomass was 109 Mg ha^(−1)(from boles≥10 cm diameter).Biomass from large-diameter trees(≥60 cm)accounted for 85%,88%,and 58%,of trees,snags,and deadwood,*** aboveground woody live and dead biomass was 668 Mg ha^(−1).The annual production of downed wood(≥10 cm diameter)from tree boles averaged 4 Mg ha^(−1) yr^(−1).Woody debris was spatially heterogeneous,varying more than two orders of magnitude from 4 to 587 Mg ha^(−1) at the scale of 20 m×20 m *** all causes of deadwood creation varied in importance between large-diameter trees and small-diameter *** of standing stems and deadwood had weak inverse distributions,reflecting the long period of time required for trees to reach large diameters following antecedent tree mortalities and the centennial scale time required for deadwood ***:Old-growth forests contain large stores of biomass in living trees,as well as in snag and deadwood biomass pools that are stable long after tree *** biomass(or carbon)in deadwood pools can lead to substantial underestimations of sequestration and stability.

关键词： Carbon sequestration Old-growth forest Pseudotsuga menziesii Tree mortality Tsuga heterophylla Wind River Forest Dynamics Plot

Demonstrating mate choice copying in spiders requires further research

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Current Zoology 2020年第2期66卷 215-216页

作者： R.tucker GILMAN Kasey FOWLER-FINN Eileen A.HEBETS School of Earth and Environmental Sciences The University of ManchesterManchesterUK Department of Biology Saint Louis UniversitySt.LouisUSA School of Biological Sciences University of Nebraska-LincolnLincolnNEUSA

Mate choice copying-when individuals learn to prefer mates or mate types that have been chosen by others-can influence trait evo-lution and speciation(Varela et al.2018;Dion et al.2019).Most examples of mate choice copying are from fish,birds,and mammals including humans(Varela et al.2018).However,2 invertebrate examples-fruit flies and wolf spiders-have been used to argue that the phenomenon may be phylogenetically widespread,and perhaps the rule rather than the exception in nature(Varela et al.2018).Here,we revisit the evidence for mate choice copying in wolf spiders(Fowler-Fimn et al.2015)in light of new data(Gilman et al.2018).Then,we discuss why mate choice copying is a phenomenon that is likely to occur in wolf spiders,and why this deserves attention.

关键词： invertebrates mate choice copying Schizocosa sexual selection speciation spiders

Targeting MYCN and ALK in resistant and relapsing neuroblastoma

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Cancer Drug Resistance 2019年第3期2卷 803-812页

作者： Elizabeth R tucker Evon Poon Louis Chesler Division of Clinical Studies The Institute of Cancer ResearchSuttonSM25NGUK

Neuroblastoma, a tumor of peripheral nerve, is the most common solid tumor of young children. In high-risk disease, which comprises approximately half of patients, death from chemotherapy-resistant, metastatic relapse is very frequent. Children who relapse exhibit clonal enrichment of two genomic alterations: high-level amplification of the MYCN oncogene, and kinase domain mutations of the anaplastic lymphoma kinase (ALK) gene. Overall survival in this patient cohort is less than 15% at 3 years, and there are few options for rationally targeted therapy. Neuroblastoma patients exhibit de novo resistance to many existing ALK inhibitors, and no clinical therapeutics to target MYCN have yet been developed. This review outlines the international efforts to uncover mechanisms of oncogenic action that are therapeutically targetable using small-molecule inhibitors. We describe a mechanistic interaction in which ALK upregulates MYCN transcription, and discuss clinical trials emerging to develop transcriptional inhibitors of MYCN, and to identify effective inhibitors of ALK in neuroblastoma patients.

关键词： Neuroblastoma anaplastic lymphoma kinase MYCN therapeutics

Habitual physical activity levels and sedentary time of children in different childcare arrangements from a nationally representative sample of Canadian preschoolers

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Journal of Sport and Health Science 2020年第6期9卷 657-663页

作者： Julie Statler Piotr Wilk Brian W.Timmons Rachel Colley Patricia tucker Faculty of Health Sciences University of Western OntarioLondonOntarioN6A 3K7Canada Schulich School of Medicine&Dentistry University of Western OntarioLondonOntarioN6A 3K7Canada Department of Pediatrics McMaster UniversityHamiltonOntarioL8S 4L8Canada Division of Health Analysis Statistics CanadaOttawaOntarioK1A 0T6Canada School of Occupational Therapy University of Western OntarioLondonOntarioN6A 3K7Canada

Background:Children spend substantial time in childcare,and the reasons parents choose a particular childcare type may differ by ***,little is known about how childcare type influences habitual(full day)activity levels among ***,exploring patterns between childcare type and habitual physical activity(PA)(i.e.,light,moderate-to-vigorous PA(MVPA),and total PA)and sedentary time(ST)in young Canadian children is ***:A nationally representative sample of preschoolers from Cycles 3 and 4 of the Canadian Health Measures Survey was used in this cross-sectional *** type(e.g.,center-based childcare,home-based childcare,home with parent,kindergarten)was reported by *** wore an Actical accelerometer for 7 *** and population-spcific cut-points were applied to delineate PA intensities and *** means and sample totals were calculated to examine average daily and hourly rates of ***:Preschoolers’rates of MVPA and total PA from the 4 childcare arrangements ranged from 65.99 min/day to 74.62 min/day(5.48-6.18 min/h)and 274.20 min/day to 281.66 min/day (22.69-23.21 min/h),respectively,while ST ranged from 443.13 min/day to 460.57 min/day(36.80-37.31 min/h).No significant differences were observed in daily or hourly rates of ***:This study provides a snapshot of the levels of PA and ST among preschoolers in various childcare settings at a national level,with no differences observed in habitual activity levels based on childcare *** research is needed to clarify the relationship between young children’s PA and childcare type,with consideration given to the quality of the childcare settings.

关键词： Early learning environment Motor activity Preschool Screen time

Dose-Dependent AGO1-Mediated Inhibition of the miRNA165/166 Pathway Modulates Stem Cell Maintenance in Arabidopsis Shoot Apical Meristem

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Plant Communications 2020年第1期1卷 179-189页

作者： Fei Du Wen Gong Sonia Bosca Matthew tucker Herve Vaucheret Thomas Laux Signalling Research Centres BIOSS and CIBSS Faculty of BiologyUniversity of FreiburgSchanzlestrasse 179104 FreiburgGermany Institut Jean-Pierre Bourgin INRAAgroParisTechCNRSUniversite Paris-Saclay78000 VersaillesFrance Sino-German Joint Research Center on Agricultural Biology Shandong Agricultural UniversityTai’anShandongChina State Key Laboratory of Plant Genomics Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China School of Agriculture Food and WineUniversity of AdelaideWaite CampusUrrbraeSAAustralia

Pluripotent stem cells localized in proliferating growth centers, the meristems, are the origin of life-long organ formation and growth in higher plants. In the shoot apical meristem of Arabidopsis thaliana, the closelyrelated ARGONAUTE proteins AGO1 and ZLL/AGO10 bind miR165/166 species to regulate mRNAs of HDZIP III transcription factors that are essential to maintaining stem cells. Several genetic studies showed thatAGO1 and ZLL/AGO10 act redundantly to maintain stem cells. By contrast, the reported biochemical datasuggested antagonistic functions: AGO1 utilizes miR165/166 to slice HD-ZIP III mRNAs, whereas ZLL/AGO10 promotes degradation of miR165/166 and thus stabilizes HD-ZIP III mRNAs. How these differentfunctions are balanced in stem cell regulation has remained enigmatic. Here, we show that autorepressionof AGO1 through miR168-mediated slicing of its own RNA is required to maintain the ability of AGO1 to suppress HD-ZIP III mRNAs. Increased AGO1 expression, either in the miR168a-2 mutant or by transgenicexpression, inhibits this ability despite the presence of high levels of miR165/166, effectively uncouplingHD-ZIP III and miR165/166 expression. AGO1 activity can be restored, however, by increasing the levelsof chaperones SQN and HSP90, which promote assembly of RNA-induced silencing complex (RISC). Thissuggests that cellular abundance of SQN and HSP chaperones limits AGO1-mediated RNA interferencein shoot meristem stem cell regulation. Localized misexpression of AGO1 indicates that the cells surrounding the shoot meristem primordium play a crucial role in stem cell development. Taken together, our studyprovides a framework that reconciles biochemical and genetic data, showing that restriction of AGO1 levelsby miR168-mediated autorepression is key to RISC homeostasis and the function of AGO1 in stem cellregulation.

关键词： Arabidopsis ARGONAUTE1 ZWILLE(ARGONAUTE10) HD-ZIP III stem cell shoot meristem

SOME DYNAMIC BEHAVIOURS OF TaS3 AND ITS POSSIBLE ELECTRONIC APPLICATIONS

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Science China Mathematics 1986年第10期29卷 1085-1095页

作者：陈倜嵘,朱维乐,P.D.COLEMAN,J.tucker Chengdu Institute of Radio Engineering Chengdu Institute of Radio Engineering University of Illinois U.S.A. University of Illinois U.S.A.

Some dynamic behaviours of quasi-1-dimensional conductor TaS3under charge density waves （CDW's） state have been carefully examined. The presence of hysteresis and phase shift in the response of CDW's to ac signals has been revealed for the first time. It has been demonstrated that the strong nonlinear electrical properties of CDW's can be used in electronic circuit to perform a number of nonlinear transformations, such as frequency conversion, modulation and heterodyne detection. This makes the 1-dimensional conductor a very attractive material for the bulk effect electronic device.A circuit model has been proposed to explain phenomenologically the observed effects.

关键词： SOME DYNAMIC BEHAVIOURS OF TaS3 AND ITS POSSIBLE ELECTRONIC APPLICATIONS CDW MHz 卜尸 TTF