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Aggregated seed arrival alters plant diversity in grassland communities

Journal of Plant Ecology 2014年第1期7卷 51-58页

作者： gregory R.Houseman Department of Biological Sciences Wichita State University1845 FairmountWichitaKS 67260USA

Aims Species aggregation is commonly seen in plant communities and may increase diversity by causing intraspecific competition to exceed interspecific *** potential source of this spatial aggregation is seed dispersal but it is unclear to what extent aggregated seed distributions affect plant diversity in real *** a field experiment,I tested whether uniform or aggregated seed arrival alters community structure and whether these effects vary with sowing *** The experiment consisted of two spatial seeding treatments(uniform and aggregated)that were fully crossed with three seed density ***,3×4-m plots were arrayed in a low-diversity grassland located in Kansas,*** plot was divided into fortyeight,0.5×0.5-m *** aggregated seeding treatments,each of the 15 species was sown into three randomly selected patches within the plot(3×15=45).To create a uniform species arrival but control for the seed addition method,all 15 species were sown into 45 individual patches(with three patches remaining unsown)within each *** mass for each species was held constant at the plot scale between uniform or aggregated treatments within a given level of the sowing density *** two growing seasons,plant density was quantified for all sown species in 15 randomly selected patches from each *** Findings I found evidence for shifts in community structure in response to the different spatial seeding *** evenness of added species was higher under aggregated than uniform sowing *** was no detectable effect of aggregated seed sowing on species richness at 3.75 m^(2) ***,when species richness was extrapolated to larger scales(11.25 m^(2)),aggregated sowing was predicted to have greater richness than uniform *** of seed aggregation on community structure were apparent only at moderate to high sowing rates,yet the latter are within the range of measured seed dispersal in s

关键词： clumped colonization rank-abundance distributions seed dispersal seed sowing

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The Emeishan large igneous province:A synthesis

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Geoscience Frontiers 2014年第3期5卷 369-394页

作者： J.gregory Shellnutt National Taiwan Normal University Department of Earth Science

The late Permian Emeishan large igneous province （EL1P） covers -0.3× 10-6 kmL of the western margin of the Yangtze Block and Tibetan Plateau with displaced, correlative units in northern Vietnam （Song Da zone）. The ELIP is of particular interest because it contains numerous world-class base metal deposits and is contemporaneous with the late Capitanian （-260 Ma） mass extinction. The flood basalts are the signature feature of the ELIP but there are also ultramafic and silicic volcanic rocks and layered mafic- ultramafic and silicic plutonic rocks exposed. The EL1P is divided into three nearly concentric zones （i.e. inner, middle and outer） which correspond to progressively thicker crust from the inner to the outer zone. The eruptive age of the ELIP is constrained by geological, paleomagnetic and geochronological evidence to an interval of 〈3 Ma. The presence of picritic rocks and thick piles of flood basalts testifies to high temperature thermal regime however there is uncertainty as to whether these magmas were derived from the subcontinental lithospheric mantle or sub-lithospheric mantle （i.e. asthenosphere or mantle plume） sources or both. The range of Sr （Isr ≈ 0.7040-0.7132）, Nd （ENd（t） ≈ -14 tO ＋8）, Pb （206-pb/204-pb1 ≈ 17.9-20.6） and Os （Yos ≈ -5 to ＋11） isotope values of the ultramafic and mafic rocks does not permit a conclusive answer to ultimate source origin of the primitive rocks but it is clear that some rocks were affected by crustal contamination and the presence of near-depleted isotope compo- sitions suggests that there is a sub-lithospheric mantle component in the system. The silicic rocks are derived by basaltic magmas/rocks through fractional crystallization or partial melting, crustal melting or by interactions between mafic and crustal melts. The formation of the Fe-Ti-V oxide-ore deposits is probably due to a combination of fractional crystallization of Ti-rich basalt and fluxing of C02-rich fluids whereas the Ni-Cu-（PGE） deposits are related

关键词： Late Permian Mantle plume Large igneous province Flood basalts Mineral deposits Uplift and doming

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Beyond the SDG 15.3.1 Good Practice Guidance 1.0 using the Google Earth Engine platform: developing a self-adjusting algorithm to detect significant changes in water use efficiency and net primary production

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Big Earth Data 2023年第1期7卷 59-80页

作者： Andrea Markos Neil Sims gregory Giuliani Foundation for the Conservation of the Chiquitano Forest Santa CruzBolivia Bolivian National Academy of Sciences La PazBolivia Centre for Earth Observation Space&AstronomyCSIROClaytonAustralia GEO LDN Initiative Institute for Environmental Sciences EnviroSPACE LabUniversity of GenevaGenevaSwitzerland Institute for Environmental Sciences GRID-GenevaUniversity of GenevaGenevaSwitzerland

Monitoring changes in Annual Net Primary Productivity(ANPP)is required for reporting on UN Sustainable Development Goal(SDG)Indicator 15.3.1:the proportion of land that is degraded over the total land *** time-series observations of ANPP to derive Water Use Efficiency(WUE;a measure of ANPP per unit of evapotranspiration)can minimize the influence of climate factors on ANPP observations and highlight the influence of non-climatic drivers of degradation such as land use *** the ANPP and WUE time series may be useful for identifying the primary drivers of land degradation,which could be used to support the Land Degradation Neutrality objectives of the UN Convention to Combat Desertification(UNCCD).This paper presents an algorithm for the Google Earth Engine(freely and openly available upon request-http://***/10.5281/zenodo.4429773)to calculate and compare ANPP and WUE time series for Santa Cruz,Bolivia,which has recently experienced an intensification in its land *** code builds on the Good Practice Guidance document(ver-sion 1)for monitoring SDG Indicator *** use the MODIS 16-day average,250 m resolution to demonstrate that the Enhanced Vegetation Index(EVI)responds faster to changes in water avail-ability than the Normalized Difference Vegetation Index(NDVI).We also consider the relationships between ANPP and *** and concordant trends may highlight good agricultural practices or increased resilience in ecosystem structure and productivity when they are positive or reducing resilience and functional integrity if *** sign and significance of the correlation between ANPP and WUE may also diverge over *** further analysis,it may be possible to interpret this relationship in terms of the drivers of change in plant productivity and ecosystem resilience.

关键词： Land degradation land productivity water use efficiency Google Earth Engine MODIS Good Practice Guidance SDG 15.3.1

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Peripheral nerve allograft:how innovation has changed surgical practice

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Plastic and Aesthetic Research 2022年第1期9卷 154-170页

作者： gregory Buncke The Buncke Clinic San FranciscoCA 94114USA

The landscape of available technology and surgical technique has changed over the last several decades,thus leading to changes in the peripheral nerve repair surgical *** is a common procedure;however,it is well recognized that nerve repair should be performed tensionless,thus preventing the ability to perform direct repair with a nerve ***,nerve gaps were repaired with ***,autograft surgery has been associated with complications such as numbness and chronic pain,which left surgeons searching for *** allografts were first utilized in the 1800s but failed due to the immune *** the modern era,they were again utilized in the 1980s,but did not gain popularity because of the need for the use of *** was evident through the 1990s that continued innovation in peripheral nerve repair was needed,as studies showed that only approximately 50% of patients with nerve gap repair achieved good or excellent *** the 2000s,the advent of an engineered nerve allograft(Avance■Nerve Graft)changed the landscape of peripheral nerve *** clinical evaluation of Avance showed that adequate sensation was able to be achieved in nerve gaps up to 30 mm,providing an alternative to *** engineered nerve allograft use became more conventional,studies showed 87.3% meaningful recovery in nerve gaps up to 50 ***,recent studies have shown that gaps between 50-70 mm have shown 69% meaningful *** technology and surgical technique continue to improve,these results are promising for large nerve gap repair.

关键词： Peripheral nerve repair nerve autograft nerve allograft nerve conduit

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Homogalacturonan MethyI-Esterification and Plant Development

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Molecular Plant 2009年第5期2卷 851-860页

作者： Sebastian Wolf gregory Mouille Jerome Pelloux Heidelberg Institute for Plant Science Im Neuenheimer Feld 360 69120 Heidelberg Germany Laboratoire de Biologie Cellulaire Institut Jean-Pierre Bourgin INRA Centre de Versailles-Grignon Route de St Cyr 78026 Versailles France EA3900-BioPI Biologie des Plantes et contrble des Insectes ravageurs Universite de Picardie 33 Rue St Leu 80039 Amiens France

The ability of a plant cell to expand is largely defined by the physical constraints imposed by its cell wall. Accordingly, cell wall properties have to be regulated during development. The pectic polysaccharide homogalacturonan is a major component of the plant primary walls. Biosynthesis and in muro modification of homogalacturonan have recently emerged as key determinants of plant development, controlling cell adhesion, organ development, and phyllotactic patterning. This review will focus on recent findings regarding impact of homogalacturonan content and methylesterification status of this polymer on plant life. Demethyl-esterification of homogalacturonan occurs through the action of the ubiquitous enzyme ＇pectin methyl-esterase＇. We here describe various strategies developed by the plant to finely tune the methyl-esterification status of homogalacturonan along key events of the plant lifecycle.

关键词： Carbohydrate metabolism cell walls Arabidopsis Pectin.

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Primary cilia as a novel horizon between neuron and environment

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Neural Regeneration Research 2017年第8期12卷 1225-1230页

作者： gregory W.Kirschen Qiaojie Xiong Medical Scientist Training Program Stony Brook University Stony Brook NY USA Department of Neurobiology & Behavior Stony Brook University Stony Brook NY USA

The primary cilium, a hair-like sensory organelle found on most mammalian cells, has gained recent attention within the field of neuroscience. Although neural primary cilia have been known to play a role in embryonic central nervous system patterning, we are just beginning to appreciate their importance in the mature organism. After several decades of investigation and controversy, the neural primary cilium is emerging as an important regulator of neuroplasticity in the healthy adult central nervous system. Further, primary cilia have recently been implicated in disease states such as cancer and epilepsy. Intriguingly, while primary cilia are expressed throughout the central nervous system, their structure, receptors, and signaling pathways vary by anatomical region and neural cell type. These differences likely bear relevance to both their homeostatic and neuropathological functions, although much remains to be uncovered. In this review, we provide a brief historical overview of neural primary cilia and highlight several key advances in the field over the past few decades. We then set forth a proposed research agenda to fill in the gaps in our knowledge regarding how the primary cilium functions and malfunctions in nervous tissue, with the ultimate goal of targeting this sensory structure for neural repair following injury.

关键词： G protein-coupled receptor sonic hedgehog seizure stroke stem cell neurogenesis plasticity

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3D tissue engineering,an emerging technique for pharmaceutical research

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Acta Pharmaceutica Sinica B 2018年第5期8卷 756-766页

作者： gregory Jensen Christian Morrill Yu Huang Department of Biological Engineering Utah State University

Tissue engineering and the tissue engineering model have shown promise in improving methods of drug delivery, drug action, and drug discovery in pharmaceutical research for the attenuation of the central nervous system inflammatory response. Such inflammation contributes to the lack of regenerative ability of neural cells, as well as the temporary and permanent loss of function associated with neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and traumatic brain injury. This review is focused specifically on the recent advances in the tissue engineering model made by altering scaffold biophysical and biochemical properties for use in the treatment of neurodegenerative diseases. A portion of this article will also be spent on the review of recent progress made in extracellular matrix decellularization as a new and innovative scaffold for disease treatment.

关键词： Tissue engineering Decellularization Neurodegenerative disease Drug screening Neuroinflammation 3D cell culture

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Sieve element occlusion provides resistance against Aphis gossypii in TGR-1551 melons

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Insect Science 2020年第1期27卷 33-48页

作者： Hsuan-Chieh Peng gregory P.Walker Department of Microbiology and Plant Pathology University of CaliforniaRiversideCaliforniaUSA Department of Entomology University of CaliforniaRiversideCaliforniaUSA

Feeding behavior and plant response to feeding were studied for the aphid Aphis gossypii Glover on susceptible and resistant melons(*** and TGR-1551,respectively).Average phloem phase bout duration on TGR-1551 was<7% of the duration on ***-seven percent of aphids on TGR-1551 never produced a phloem phase that attained ingestion(EPG waveform E2)in contrast to only 7% of aphids on *** bout duration of waveform E2(scored as zero if phloem phase did not attain E2)on TGR-1551 was<3% of the duration on ***,average bout duration of EPG waveform El(sieve element salivation)was 2.8 times greater on TGR-1551 than on *** a second experiment,liquid nitrogen was used to rapidly cryofix leaves and aphids within a few minutes after the aphids penetrated a sieve *** near the penetration site was then examined by confocal laser scanning ***-six percent of penetrated sieve elements were occluded by protein in TGR-1551 in contrast to only 28% in *** in TGR-1551,occlusion was also observed in nearby nonpenetrated sieve ***,a calcium channel blocker,trivalent lanthanum,was used to prevent phloem occlusion in TGR-1551,and *** feeding behavior and the plants phloem response were compared between lanthanum-treated and control *** treatment eliminated the sieve element protein occlusion response and the aphids readily ingested phloem sap from treated *** study provides strong evidence that phloem occlusion is a mechanism for resistance against *** in TGR-1551.

关键词： aphid feeding behavior Aphis gossypii Cucumis melo insect-plant resistance phloem occlusion sieve element occlusion proteins

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The enduring link between forest cover and rainfall： a historical perspective on science and policy discussions

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Forest Ecosystems 2018年第1期5卷 53-61页

作者： Brett M. Bennett gregory A. Barton School of Humanities and Communication Arts Western Sydney UniversityLocked Bag 1797PenrithNSW 2751Australia Department of Historical Studies Faculty of HumanitiesUniversity of JohannesburgC-Ring 2-Orange Block(Kingsway Campus)Corner Kingsway and University RoadAuckland ParkSouth Africa

Background： This article traces the history of scientific ideas connecting forest cover with rainfall to inform ongoing debates about whether forests are net users or producers of water in the hydrological cycle. Scholars of the supply-side school argue that forests are net producers and magnifiers that increase rainfall at regional scales. Supply-side scholars seek to challenge the dominance of demand-side thinking. The demand-side school emphasizes that trees are net users of water within a catchment that decrease overall water available for other users. This scientific debate has significant implications for the development of policies to manage forests and water. Results： Scientists have debated the question of whether forests improve or worsen water balance for over two hundred years. Connections between forests and rainfall gained prominence in scientific circles during the second half of the nineteenth century and again during the past three decades. The popularity of forest- rainfall connections has paralleled societal and scientific interest in anthropogenic climate change and deforestation. Theories connecting forests with rainfall peaked in popularity in the 1850s to 1880s, a period when scientists expressed alarm that deforestation caused regional declines in precipitation. Forests were understood to create rain within a locality and region. Scientific consensus shifted by the early twentieth century to the view that forests did not play a significant role in determining rainfall. The forest-rainfall connection reemerged in the 1980s alongside advances in climate modelling and growing fears of anthropogenic global warming and tropical deforestation. Using new data and theories, supply-side advocates have once again placed a strong forest-rainfall connection into scientific prominence. Conclusion： Supply-side management policies have a checkered history that should elicit caution, while demand-side policies, which are based on almost a century of hydrolog

关键词： Climate change Environmental history Forests Hydrology Rain Water

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Dynamic Modeling, Testing, and Stability Analysis of an Ornithoptic Blimp

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Journal of Bionic Engineering 2011年第4期8卷 375-386页

作者： John Dietl Thomas Herrmann gregory Reich Ephrahim Garcia Sibley School of Mechanical and Aerospace Engineering Cornell University Ithaca New York USA Air Force Research Laboratory Wright-Patterson AFB OH 45433-7542 USA

In order to study omithopter flight and to improve a dynamic model of flapping propulsion, a series 0f tests are conducted on a flapping-wing blimp. The blimp is designed and constructed from mylar plastic and balsa wood as a test platform for aerodynamics and flight dynamics. The blimp, 2.3 meters long and 420 gram mass, is propelled by its flapping wings. Due to buoyancy the wings have no lift requirement so that the distinction between lift and propulsion can be analyzed in a flight platform at low flight speeds. The blimp is tested using a Vicon motion tracking system and various initial conditions are tested including accelerating flight from standstill, decelerating from an initial speed higher than its steady state, and from its steady-state speed but disturbed in pitch angle. Test results are used to estimate parameters in a coupled quasi-steady aerodynamics/Newtonian flight dynamics model. This model is then analyzed using Floquet theory to determine local dynamic modes and stability. It is concluded that the dynamic model adequately describes the vehicle＇s nonlinear behavior near the steady-state velocity and that the vehicle＇s linearized modes are akin to those of a fixed-wing aircraft.

关键词： omithopter blimp flight dynamics stability analysis

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