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Acacia mangium Willd: benefits and threats associated with its increasing use around the world

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Forest Ecosystems 2019年第1期6卷 13-25页

作者： Lydie-Stella Koutika david m.Richardson CRDPI Centre de Recherche sur la Durabilité et la Productivité des Plantations Industrielles Centre for Invasion Biology Department of Botany & Zoology Stellenbosch University

Background: Acacia mangium, a fast-growing tree native to parts of Indonesia, Papua New Guinea and Australia,has been cultivated outside its native environment and introduced into humid tropical lowland regions of Asia,South America and Africa over the last few decades. It is a multipurpose tree used in agroforestry, forestry and for restoration of degraded lands. It is also highly invasive in many regions where it has been introduced outside its native range. This paper reviews evidence of its obvious benefits and its negative impacts on ***: A literature review on Australian acacias and especially on A. mangium was undertaken to highlight both benefits and threats associated with their increasing worldwide use outside their native ***: Through N_2 fixed from the atmosphere, A. mangium improves soil fertility, especially by increasing N status and soil C accretion when introduced to N-limited areas; it thus has the potential to restore nutrient cycling in degraded systems. No studies have, however, been done to assess the effectiveness of A. mangium in restoring biodiversity of degraded lands. most Australian acacias have traits that facilitate invasiveness, and 23 species have been recorded as invasive to date. A. mangium has been reported as invasive in Asia, Indonesia, Pacific Islands,Indian Ocean Islands, southern Africa and Brazil. Research on other invasive Australian acacias in several parts of the world has elucidated the types of impacts that are likely in different types of ecosystems and key options for mitigating ***: A. mangium has the potential to restore nutrient cycling in degraded systems, but is highly invasive wherever it is planted. many parts of the world have a large invasion debt for this species. Experience with other invasive acacias around the world suggests a suite of interventions that could be used to reduce invasions and mitigate impacts. Careful risk assessments should be undertaken prior to

关键词： Biodiversity Biological invasions C sequestration Soil N status Tree invasions

CD40 interacts directly with RAG1 and RAG2 in autoaggressive T cells and Fas prevents CD40-induced RAG expression

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Cellular & molecular Immunology 2013年第6期10卷 483-489页

作者： Gisela m Vaitaitis david H Wagner Jr Department of medicine and Webb-Waring Center University of Colorado Denver Aurora CO USA

CD4＋ T cells expressing CD40 （Th40 cells） constitute a pathogenic T-cell subset that is necessary and sufficient to transfer autoimmune disease. We have previously demonstrated that CD40 signals peripheral Th40 cells to induce RAG1 and RAG2 expression, proteins necessary for the expression of T-cell receptor （TCR）, leading to TCR revision. The dependency of TCR expression in the thymus on RAG proteins has long been known. However, despite numerous publications, there is controversy as to whether TCR expression can be altered in the periphery, post-thymic selective pressures. Therefore, a better understanding of TCR expression in primary peripheral cells is needed. We now show that the CD40 protein itself interacts with RAG1 and RAG2 as well as with Ku70 and translocates to the nucleus in Th40 cells. This indicates that the CD40 molecule is closely involved in the mechanism of TCR expression in the periphery. In addition, Fas signals act as a silencing mechanism for CD40-induced RAGs and prevent CD40 translocation to the nucleus. It will be important to further understand the involvement of CD40 in peripheral TCR expression and how TCR revision impacts auto-antigen recognition in order to effectively target and tolerize autoaggressive T cells in autoimmune disease.

关键词： autoimmunity CD40 Fas RAG T-cell receptor

Province-scale commonalities of some world-class gold deposits:Implications for mineral exploration

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Geoscience Frontiers 2015年第3期6卷 389-399页

作者： david I.Groves m.Santosh Centre for Exploration Targeting UWA State Key Laboratory of Geological Processes and mineral Resources China University of Geosciences Centre for Tectonics Resources and Exploration Dept.of Earth SciencesUniversity of Adelaide Division of Interdisciplinary Science Faculty of ScienceKochi University

Discovery rates for all metals, including gold, are declining, the cost per significant discovery is increasing sharply, and the economic situation of the industry is one of low base rate. The current hierarchical structure of the exploration and mining industry makes this situation difficult to redress. Economic geologists can do little to influence the required changes to the overall structure and philosophy of an industry driven by business rather than geological principles, However, it should be possible to follow the lead of the oil industry and improve the success rate of greenfield exploration, necessary for the next group of lower-exploration-spend significant mineral deposit discoveries. Here we promote the concept that mineral explorers need to carefully consider the scale at which their exploration targets are viewed. It is necessary to carefully assess the potential of drill targets in terms of terrane to province to district scale, rather than deposit scale, where most current economic geology research and conceptual thinking is concentrated. If orogenic, IRGD, Carlin-style and IOCG gold-rich systems are viewed at the deposit scale, they appear quite different in terms of conventionally adop- ted research parameters. However, recent models for these deposit styles show increasingly similar source-region parameters when viewed at the lithosphere scale, suggesting common tectonic settings. It is only by assessing individual targets in their tectonic context that they can be more reliably ranked in terms of potential to provide a significant drill discovery. Targets adjacent to craton margins, other lithosphere boundaries, and suture zones are clearly favoured for all of these gold deposit styles, and such exploration could lead to incidental discovery of major deposits of other metals sited along the same tectonic boundaries.

关键词： mineral exploration Gold deposits Tectonic settings mining industry Discovery rate

Contemporary and Historic Population Structure of Abies spectabilis at Treeline in Barun Valley,Eastern Nepal Himalaya

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Journal of mountain Science 2015年第3期12卷 558-570页

作者： Parveen Kumar CHHETRI david m.CAIRNS Department of Geography Texas A&M UniversityCollege Station

Treeline ecotone dynamics of Abies spectabilis （D. Don） mirb. in the Barun valley, makalu Barun National Park, eastern Nepal Himalaya were studied by establishing seven plots （20 m x variable length） from the foresfline to the tree species limit： three plots on the south- and north-facing slopes each （S1-S3, N1-N3）, and one plot on the east- facing slope （E） in the relatively undisturbed forests. A dendroecological method was used to study treeline advance rate and recruitment pattern. In all the plots, most trees established in the early 20th century, and establishment in the second half of the 20th century was confined to the foresfline area. Treeline position has not advanced substantially in the Barun valley, with 0nly 22 m average elevational shift in the last 13o years, and with average current shifting rate of 14 cm/yr. moreover, no significant relationship was found between tree age and elevation on the south-, north-, and east-facing slopes. The number of seedlings and saplings in near the treeline area was negligible compared to that near the foresfline area. Therefore, A. spectabilis treeline response to the temperature change was slow, despite the increasing temperature trend in the region. Beside the temperature change, factors such as high inter-annual variability in temperature, dense shrub cover, and local topography also play an important role in treeline advance and controlling recruitment pattern above the treeline.

关键词： Climate change Treeline ecotone Treeline advance Recruitment pattern

The giant Jiaodong gold province： The key to a unified model for orogenic gold deposits？

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Geoscience Frontiers 2016年第3期7卷 409-417页

作者： david I.Groves m.Santosh Centre for Exploration Targeting UWA Cmwley 6009 WA Australia Centre for Tectonics Resources and Exploration Department of Earth Sciences University of Adelaicle SA 5005 Australia State Key Laboratory of Geological Processes and mineral Resources China University of Geosciences Beijing 100083 China Division of Interdisciplinary Science Faculty of Science Kochi University Kochi 780-8520 Japan

Although the term orogenic gold deposit has been widely accepted for all gold-only lode-gold deposits,with the exception of Carlin-type deposits and rare intrusion-related gold systems,there has been continuing debate on their *** syngenetic models and hydrothermal models dominated by meteoric fluids are now clearly ***-hydrothermal models fail to explain the genesis of orogenic gold deposits because of the lack of consistent spatially- associated granitic intrusions and inconsistent temporal *** most plausible,and widely accepted,models involve metamorphic fluids,but the source of these fluids is hotly *** within deeper segments of the supracrustal successions hosting the deposits,the underlying continental crust,and subducted oceanic lithosphere and its overlying sediment wedge all have their *** orogenic gold deposits of the giant Jiaodong gold province of China,in the delaminated North China Craton,contain ca.120 ma gold deposits in Precambrian crust that was metamorphosed over 2000 million years prior to gold *** only realistic source of fluid and gold is a subducted oceanic slab with its overlying sulfide-rich sedimentary package,or the associated mantle *** could be viewed as an exception to a general metamorphic model where orogenic gold has been derived during greenschist- to amphibolite-facies metamorphism of supracrustal rocks：basaltic rocks in the Precambrian and sedimentary rocks in the ***,if a holistic view is taken,Jiaodong can be considered the key orogenic gold province for a unified model in which gold is derived from late-orogenic metamorphic devolatilization of stalled subduction slabs and oceanic sediments throughout Earth *** latter model satisfies all geological,geochronological,isotopic and geochemical constraints but the precise mechanisms of auriferous fluid release,like many other subduction-related processes,are model-driv

关键词： Jiaodong province Orogenic gold metamorphic fluids Subduction zones Tectonics

Dendroclimatic response of Abies spectabilis at treeline ecotone of Barun Valley, eastern Nepal Himalaya

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Journal of Forestry Research 2016年第5期27卷 1163-1170页

作者： Parveen Kumar Chhetri david m.Cairns Department of Geography Texas A&M UniversityCollege StationTX 77843-3147USA

A dendroclimatic study was conducted in the treeline ecotone of Barun Valley, eastern Nepal, to determine the tree-ring climate response and ring width trend of Abies spectabilis. A 160-year-old chronology, from 1850 to 2010, was developed from 38 tree-ring samples. No higher growth in recent decades was observed in tree-ring width in this area. The mean temperature of the current year in February and in the combined winter months of December, January, and February showed significant positive correlation with tree-ring width, although no significant correlation was found between tree-ring width and the precipitation pattern of the region. This tree-ring climate response result is different from that in other studies in Nepal, which could be attributed to location and elevation.

关键词： spectabilis Dendroclimatology Treeline ecotone Abies Climate response Tree-ring width

Dynamic Bubble Behaviour during microscale Subcooled Boiling

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Chinese Physics Letters 2005年第11期22卷 2881-2884页

作者：王昊彭晓峰 david m. Christopher Laboratory of Phase-Change and Interracial Transport Phenomena Department of Thermal Engineering Tsinghua University Beijing 100084

Bubble cycles, including initiation, growth and departure, are the physical basis of nucleate boiling. The present investigation, however, reveals unusual bubble motions during subcooled nucleate boiling on microwires 25 or 100μm in diameter. Two types of bubble motions, bubble sweeping and bubble return, are observed in the experiments. Bubble sweeping describes a bubble moving back and forth along the wire, which is motion parallel to the wire. Bubble return is the bubble moving back to the wire after it has detached or leaping above the wire. Theoretical analyses and numerical simulations are conducted to investigate the driving mechanisms for both bubble sweeping and return. marangoni flow from warm to cool regions along the bubble interface is found to produce the shear stresses needed to drive these unusual bubble movements.

关键词： Dynamic Bubble Behaviour during microscale Subcooled Boiling

Genomic organization and evolution of ruminant lysozyme c genes

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Zoological Research 2015年第1期36卷 1-17页

作者： david m.IRWIN Department of Laboratory medicine and Pathobiology University of Toronto Banting and Best Diabetes Centre University of Toronto

Ruminant stomach lysozyme is a long established model of adaptive gene evolution. Evolution of stomach lysozyme function required changes in the site of expression of the lysozyme c gene and changes in the enzymatic properties of the enzyme. In ruminant mammals, these changes were associated with a change in the size of the lysozyme c gene family. The recent release of near complete genome sequences from several ruminant species allows a more complete examination of the evolution and diversification of the lysozyme c gene family. Here we characterize the size of the lysozyme c gene family in extant ruminants and demonstrate that their pecoran ruminant ancestor had a family of at least 10 lysozyme c genes, which included at least two pseudogenes. Evolutionary analysis of the ruminant lysozyme c gene sequences demonstrate that each of the four exons of the lysozyme c gene has a unique evolutionary history, indicating that they participated independently in concerted evolution. These analyses also show that episodic changes in the evolutionary constraints on the protein sequences occurred, with lysozyme c genes expressed in the abomasum of the stomach of extant ruminant species showing the greatest levels of selective constraints.

关键词： lysozyme ruminant evolutionary Genomic extant stomach genomic constraints Ailuropoda duplication

Communication,Computation,and Governance:A multiscalar Vantage on the Prehispanic mesoamerican World

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Journal of Social Computing 2022年第1期3卷 91-118页

作者： Gary m.Feinman david m.Carballo the Negaunee Integrative Research Center Field Museum of Natural HistoryChicagoIL 60605USA Anthropology Archaeologyand Latin American StudiesBoston UniversityBostonMA 02215USA

Writing has often been put forth as one indicator of *** correspondence dovetails with the even broader cross-species expectation that the degrees of social complexity and levels of computational communication should closely *** in a general sense across human cooperative arrangements,a basic relationship between these variables undoubtedly exists,more detailed and fine-grained analyses indicate important axes of ***,our focus is on prehispanic mesoamerica and the means of computation and communication employed over more than three millennia(ca.1500 BCE-1520 CE).We take a multiscalar and diachronic analytical frame,in which we look at 30 central places,six macroregions,and mesoamerica as *** unraveling elements of“social complexity”,and decoupling computation from communication,we illustrate that institutional differences in governance had a marked effect on the specific modes and technologies through which prehispanic mesoamerican peoples communicated across time and *** and spatial scale,though relevant,do not alone determine time/space diversity in media of computational *** article is part of the theme issue“Evolution of Collective Computational Abilities of(Pre)Historic Societies”.

关键词： mesoamerica archaeology communication computation writing polity scale calendrics maya Aztec