Invasion of winter moth in New England: Effects of defoliation and site quality on tree mortality.

Abstract Widespread and prolonged defoliation by the European winter moth, Operophtera brumata L., has occurred in forests of eastern Massachusetts for more than a decade and populations of winter moth continue to invade new areas of New England. This study characterized the forests of eastern Massachusetts invaded by winter moth and related the duration of winter moth defoliation estimated using dendrochronology to observed levels of tree mortality and understory woody plant density. Quercus basal area mortality in mixed Quercus and mixed Quercus-Pinus strobus forests in eastern Massachusetts ranged from 0-30%; mortality of Quercus in these forests was related to site quality and the number of winter moth defoliation events. In addition, winter moth defoliation events lead to a subsequent increase in understory woody plant density. Our results indicate that winter moth defoliation has been an important disturbance in New England forests that may have lasting impacts

Characterisation of five GH16 glycanase and transglycanase activities and of their hemicellulosic substrates

Plant primary cell walls are hydrated extracellular complexes composed largely of polysaccharides: cellulose, hemicellulose and pectin. Cell wall constituents and composition vary in cell-, environment-, and species-dependent manners. For example, within land plant hemicelluloses xyloglucan is ubiquitous while mixedlinkage (1→3),(1→4)-β-D-glucan (MLG) is found only in the Poales and Equisetum. Glycosyl hydrolase 16 (GH16) enzyme family members include numerous enzymes with pertinence to the understanding of the ‘lives’ of cell wall hemicelluloses. However, despite this, the details of the interactions between GH16 enzymes and their substrates have often not been elucidated. Likewise, the true preferences of many of these enzymes and the range of substrates which they can utilise remain to be fully explored. By providing a greater wealth of information for the correlation of enzyme structure with reaction catalysed, such an understanding would enable better predictions of the activities of novel enzymes. Crucially, this would also allow better identification of roles performed by these enzymes in planta as well as of the potential applications of these enzymes. This work sought to further our understanding of the interactions between GH16 enzymes and their substrates by the study of five activities exhibited by GH16 enzymes – xyloglucan endotransglucosylase (XET), xyloglucan endoglucanase/hydrolase (XEG/XEH), mixed-linkage glucan : xyloglucan endotransglucosylase (MXE), lichenase and cellulose : xyloglucan endotransglucosylase (CXE). All of the analysed activities act on xyloglucan and/or MLG. Of particular focus is the novel enzyme MXE from the evolutionarily isolated genus Equisetum (horsetail), which acts on both. Notable findings include: identification of MXE/CXE gene; determination of the substrate specificity of MXE; defining of the sites of attack of lichenase, XEG, XET and MXE; discovery of novel xyloglucan structures and discrepancies between the xyloglucan present in different barley organs

The Impact of Driving Knowledge on Motor Vehicle Fatalities

This paper analyzes the influence of driving knowledge on highway safety by estimating regression models on U.S. state-level data over six years (2005 through 2010). The models incorporate a representative set of motor vehicle fatality determinants. Driving knowledge—as measured by performance on the GMAC Insurance National Drivers Test—has a statistically significant life-saving effect. Negatively related to the motor vehicle death rate and statistically significant are: real per capita income, precipitation, seat belt use, and a linear trend. Statistically significant positive associations with the rate are found for: the ratio of rural to urban driving, temperature, the percentage of young drivers, the percentage of old drivers, and alcohol consumption

Unproceedings of the Fourth .Astronomy Conference (.Astronomy 4), Heidelberg, Germany, July 9-11 2012

The goal of the .Astronomy conference series is to bring together astronomers, educators, developers and others interested in using the Internet as a medium for astronomy. Attendance at the event is limited to approximately 50 participants, and days are split into mornings of scheduled talks, followed by 'unconference' afternoons, where sessions are defined by participants during the course of the event. Participants in unconference sessions are discouraged from formal presentations, with discussion, workshop-style formats or informal practical tutorials encouraged. The conference also designates one day as a 'hack day', in which attendees collaborate in groups on day-long projects for presentation the following morning. These hacks are often a way of concentrating effort, learning new skills, and exploring ideas in a practical fashion. The emphasis on informal, focused interaction makes recording proceedings more difficult than for a normal meeting. While the first .Astronomy conference is preserved formally in a book, more recent iterations are not documented. We therefore, in the spirit of .Astronomy, report 'unproceedings' from .Astronomy 4, which was held in Heidelberg in July 2012.Comment: 11 pages, 1 figure, .Astronomy 4, #dotastr

Effects of accidental microconstriction on the quantized conductance in long wires

We have investigated the conductance of long quantum wires formed in GaAs/AlGaAs heterostructures. Using realistic fluctuation potentials from donor layers we have simulated numerically the conductance of four different kinds of wires. While ideal wires show perfect quantization, potential fluctuations from random donors may give rise to strong conductance oscillations and degradation of the quantization plateaux. Statistically there is always the possibility of having large fluctuations in a sample that may effectively act as a microconstriction. We therefore introduce microconstrictions in the wires by occasional clustering of donors. These microconstrictions are found to restore the quantized plateaux. A similar effect is found for accidental lithographic inaccuracies.Comment: 4 pages, 2 figures, paper for NANO2002 symposium, will appear in SPIE proceeding

Effects of Invasive Winter Moth Defoliation on Tree Radial Growth in Eastern Massachusetts, USA

Winter moth, Operophtera brumata L. (Lepidoptera: Geometridae), has been defoliating hardwood trees in eastern Massachusetts since the 1990s. Native to Europe, winter moth has also been detected in Rhode Island, Connecticut, eastern Long Island (NY), New Hampshire, and Maine. Individual tree impacts of winter moth defoliation in New England are currently unknown. Using dendroecological techniques, this study related annual radial growth of individual host (Quercus spp. and Acer spp.) trees to detailed defoliation estimates. Winter moth defoliation was associated with up to a 47% reduction in annual radial growth of Quercus trees. Latewood production of Quercus was reduced by up to 67% in the same year as defoliation, while earlywood production was reduced by up to 24% in the year following defoliation. Winter moth defoliation was not a strong predictor of radial growth in Acer species. This study is the first to document impacts of novel invasions of winter moth into New England

Folding Of Xylan Onto Cellulose Fibrils In Plant Cell Walls Revealed By Solid-state Nmr

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Exploitation of plant lignocellulosic biomass is hampered by our ignorance of the molecular basis for its properties such as strength and digestibility. Xylan, the most prevalent non-cellulosic polysaccharide, binds to cellulose microfibrils. The nature of this interaction remains unclear, despite its importance. Here we show that the majority of xylan, which forms a threefold helical screw in solution, flattens into a twofold helical screw ribbon to bind intimately to cellulose microfibrils in the cell wall. C-13 solid-state magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, supported by in silico predictions of chemical shifts, shows both two-and threefold screw xylan conformations are present in fresh Arabidopsis stems. The twofold screw xylan is spatially close to cellulose, and has similar rigidity to the cellulose microfibrils, but reverts to the threefold screw conformation in the cellulose-deficient irx3 mutant. The discovery that induced polysaccharide conformation underlies cell wall assembly provides new principles to understand biomass properties.7BBSRC Grant via BBSRC Sustainable Bioenergy Cell Wall Sugars Programme [BB/G016240/1]CNPq [159341/2011-6, 206278/2014-4]Royal SocietyLeverhulme Trust grant for the Centre for Natural Material InnovationEPSRCBBSRCUniversity of WarwickBirmingham Science City Advanced Materials ProjectsAdvantage West Midlands (AWM)European Regional Development Fund (ERDF)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq