Ecological and evolutionary processes at expanding range margins

Many animals are regarded as relatively sedentary and specialized in marginal parts of their geographical distributions. They are expected to be slow at colonizing new habitats. Despite this, the cool margins of many species' distributions have expanded rapidly in association with recent climate warming. We examined four insect species that have expanded their geographical ranges in Britain over the past 20 years. Here we report that two butterfly species have increased the variety of habitat types that they can colonize, and that two bush cricket species show increased fractions of longer-winged (dispersive) individuals in recently founded populations. Both ecological and evolutionary processes are probably responsible for these changes. Increased habitat breadth and dispersal tendencies have resulted in about 3- to 15-fold increases in expansion rates, allowing these insects to cross habitat disjunctions that would have represented major or complete barriers to dispersal before the expansions started. The emergence of dispersive phenotypes will increase the speed at which species invade new environments, and probably underlies the responses of many species to both past and future climate change

Geochemical-geophysical investigations, Fairbanks district

Trace element distribution in a subarctic valley in the Cleary Hill area of the Fairbanks gold district has been studied. Zinc and arsenic have been found excellent pathfinder elements for auriferous deposits. Methods of analysis for copper, lead, zinc, molybdenum, silver and arsenic as well as heavy metals are discussed. The University of Alaska method #2 has been improved, Terrain, slope, and frozen ground have little effect upon the distribution of trace elements associated with the Cleary H i l l vein. A new method for the determination of zinc using dilute acid is proposed. Analysis of geochemical data by trend surface procedures proved effective for localization of anomalies

Phenomena exposure from the large scale gas injection test (Lasgit) dataset using a bespoke data analysis toolkit

The Large Scale Gas Injection Test (Lasgit) is a field-scale experiment designed to study the impact of gas buildup and subsequent migration through an engineered barrier system. Lasgit has a substantial experimental dataset containing in excess of 21 million datum points. The dataset is anticipated to contain a wealth of information, ranging from long-term trends and system behaviours to small-scale or ‘second-order’ features. In order to interrogate the Lasgit dataset, a bespoke computational toolkit, designed to expose difficult to observe phenomena, has been developed and applied to the dataset. The preliminary application of the toolkit, presented here, has resulted in a large number of phenomena being indicated/quantified, including highlighting of second-order events (small gas flows, perturbations in stress/pore-water sensors, etc.) and quantification of temperature record frequency content. Localized system behaviour has been shown to occur along with systematic aberrant behaviours that remain unexplained

The California coastal wave monitoring and prediction system

AbstractA decade-long effort to estimate nearshore (20m depth) wave conditions based on offshore buoy observations along the California coast is described. Offshore, deep water directional wave buoys are used to initialize a non-stationary, linear, spectral refraction wave model. Model hindcasts of spectral parameters commonly used in nearshore process studies and engineering design are validated against nearshore buoy observations seaward of the surfzone. The buoy-driven wave model shows significant skill at most validation sites, but prediction errors for individual swell or sea events can be large. Model skill is high in north San Diego County, and low in the Santa Barbara Channel and along the southern Monterey Bay coast. Overall, the buoy-driven model hindcasts have relatively low bias and therefore are best suited for quantifying mean (e.g. monthly or annual) nearshore wave climate conditions rather than extreme or individual wave events. Model error correlation with the incident offshore wave energy, and between neighboring validation sites, may be useful in identifying sources of regional modeling errors

Application of PCR to a clinical and environmental investigation of a case of equine botulism

PCR for the detection of botulinum neurotoxin gene types A to E was used in the investigation of a case of equine botulism. Samples from a foal diagnosed with toxicoinfectious botulism in 1985 were reanalyzed by PCR and the mouse bioassay in conjunction with an environmental survey. Neurotoxin B was detected by mouse bioassay in culture enrichments of serum, spleen, feces, and intestinal contents. PCR results compared well with mouse bioassay results, detecting type B neurotoxin genes in these samples and also in a liver sample. Other neurotoxin types were not detected by either test. Clostridium botulinum type B was shown to be prevalent in soils collected from the area in which the foal was raised. Four methods were used to test for the presence of botulinum neurotoxin-producing organisms in 66 soil samples taken within a 5-km radius: PCR and agarose gel electrophoresis (types A to E), PCR and an enzyme-linked assay (type B), hybridization of crude alkaline cell lysates with a type B-specific probe, and the mouse bioassay (all types). Fewer soil samples were positive for C. botulinum type B by the mouse bioassay (15%) than by any of the DNA-based detection systems. Hybridization of a type B-specific probe to DNA dot blots (26% of the samples were positive) and PCR-enzyme-linked assay (77% of the samples were positive) were used for the rapid analysis of large numbers of samples, with sensitivity limits of 3 x 10(6) and 3,000 cells, respectively. Conventional detection of PCR products by gel electrophoresis was the most sensitive method (300-cell limit), and in the present environmental survey, neurotoxin B genes only were detected in 94% of the samples

The chronology and kinematics of late Palaeozoic deformation in the NW contact metamorphic aureole of the Land's End Granite

A structural investigation of coastal exposures between Cape Cornwall and Pendeen Watch, in the NW contact metamorphic aureole of the Land’s End Granite, has confirmed a similar deformation chronology as in a reference section around Porthleven. D1 deformation is represented by an ubiquitous bedding-parallel S1 cleavage although F1 folds have not been recognised. D2 deformation is more localised and characterised by open F2 folds that verge WSW to NW and are associated with an ENE to SE dipping S2 crenulation cleavage. These structures are commonly obscured by later deformation and contact metamorphism and have not been described previously. A set of steeply inclined NNW-SSE trending, and subordinate set of moderately SE dipping, post-D2 metamorphic quartz veins formed coevally during an episode of strike-slip deformation prior to, or during, the early stages of D3 deformation. D3 deformation is widespread and represented by F3 folds and a WNW to NW dipping S3 crenulation cleavage; it has been recorded previously as D2 deformation. Two orders of F3 folds are developed; first order folds have a wavelength of up to 50 m, verge ESE, and result in vertical or steeply inclined bedding and S1 cleavage on their short limbs. Second order folds usually have a wavelength of 1 m or less and usually verge ESE, unless on the short limb of first order folds, where they verge WNW. Previously published data, indicating a dominant NW to WNW vergence of F3 folds on the northern flank of the Land’s End Granite are incorrect. D3 structures are consistent with formation during the extensional reactivation of large-scale thrust faults. Granite emplacement post-dates all three episodes of ductile deformation but granites and their host rocks are deformed by a late brittle expression of D3 deformation. The Land’s End pluton has been accommodated, at the current exposure level, primarily by roof uplift that has resulted in the tilting of D3 and earlier structures to the NW by 40-50º; this may have been accompanied by differential vertical axis rotations of the host rock. The last significant Palaeozoic deformation episode formed F4 folds and S4 cleavage and was a consequence of Mid- to Late Permian ENE-WSW shortening

Applications of Solid Freeform Fabrication at the Naval Research Laboratory

Solid Freeform Fabrication (SFF) and related techniques are used at the Naval Research Laboratory (NRL) for a variety of materials related investigations. Research and applications conducted over the past few years are described including: Helisys Laminated Object Manufacturing System (LOMS) fabrication of: ceramic piezoelectric actuators, tooling for multifunctional materials, and anatomical prototypes for surgical visualization; fabrication of mesoscale electronic and sensor components using a laser forward transfer direct write technique; and visualization of complex, 3-D microstructures using a Stratasys Fused-Deposition Modeler. The paper closes with a brief overview of future SFF related work at the NRL.Support for this work from DARPA, Office of Naval Research, and the Naval Research Laboratory Core Research Program is gratefully acknowledged.Mechanical Engineerin