Natural and anthropogenic stressors, including parasites and pesticides, may induce oxidative stress in animals. Measuring oxidative stress responses in sentinel species that are particularly responsive to environmental perturbations not only provides insight into host physiology but is also a useful readout of ecosystem health. Newly metamorphosed northern leopard frogs (Lithobates pipiens), a sentinel species, were collected from agricultural and non-agricultural wetlands exposed to varying concentrations of the herbicide atrazine. Significant effects of certain parasites' abundance and their interaction with atrazine exposure on frog oxidative stress were identified. Specifically, increased protein levels were detected in frogs infected with echinostome metacercariae. In addition, the nematode Oswaldocruzia sp. was significantly associated with increased thiol concentration and catalase activity. Significant parasite × atrazine interactions were observed for atrazine exposure and the abundance of Oswaldocruzia sp. on thiol, as thiol concentrations increased with parasite abundance at low atrazine localities and decreased in high atrazine wetlands. In addition, a significant interaction between the abundances of Oswaldocruzia sp. and gorgoderid trematodes on thiol concentrations was observed. These findings demonstrate that studies of oxidative stress on animals in natural ecosystems should account for the confounding effects of parasitism, particularly for amphibians in agricultural landscapes.

A total of 38 long-term care facilities within a region participated in a 3-month quality improvement initiative focused on environmental cleaning and disinfection. Significant improvements in daily and discharge cleaning were observed during the project period. Further study of the sustainability and clinical impact of this type of initiative is warranted.

Annually dated tree-rings of 509 live and deadwood limber pine (Pinus flexilis) samples from the semi-arid Wassuk Range, Nevada, yielded a 3996-yr record extending from 1983 BC to AD 2013. Correlations of radial growth with climate were positive for water relations and negative for summer temperatures. Long-term trends of ring-width corresponded to climate variability documented from other proxies, including low growth during the Late Holocene Dry Period and Medieval Climate Anomaly (MCA) and elevated growth during cool, wet periods of the Neoglacial and Little Ice Age. Spline fit of the data indicated that growth decrease in the last 20 years was second lowest on record, surpassed by lowest growth at 20 BC—AD 150. Demographics of limber pine by aspect and elevation were not strongly related to long-term climate dynamics, except in the case of extirpations on all but north aspects at the end of the MCA. Pines occurred persistently on north aspects, where a continuous record existed to present. Elevation shifts were not obvious on any aspect, and no evidence existed for migration above current treeline. Non-climatic factors appear to interact with climate to make north slopes refugial for upland pines in semi-arid regions across four millennia.

It has been an underlying assumption in many studies that near-surface layers imaged by ground-penetrating radar (GPR) can be interpreted as depositional markers or isochrones. It has been shown that GPR layers can be approximately reproduced from the measured electrical properties of ice, but these material layers are generally narrower and more closely spaced than can be resolved by typical GPR systems operating in the range 50−400 MHz. Thus GPR layers should be interpreted as interference patterns produced from closely spaced and potentially discontinuous material layers, and should not be assumed to be interpretable as precise markers of isochrones. We present 100 MHz GPR data from Lyddan Ice Rise, Antarctica, in which near-surface (<50 m deep) layers are clearly imaged. The growth of the undulations in these layers with depth is approximately linear, implying that, rather than resulting from a pattern of vertical strain rate, they do correspond to some pattern of snowfall variation. Furthermore, comparison of the GPR layers with snow-stake measurements suggests that around 80% of the rms variability in mean annual accumulation is present in the GPR layers. The observations suggest that, at least in this case, the GPR layers do approximate isochrones, and that patterns of snow accumulation over Lyddan Ice Rise are dominated by extremely persistent spatial variations with only a small residual spatial variability. If this condition is shown to be widely applicable it may reduce the period required for measurements of surface elevation change to be taken as significant indications of mass imbalance.

Ground-penetrating radar (GPR) is becoming a commonly applied technique in geomorphology. However, its use in the study of subglacial bedforms has yet to be fully explored and exploited. This paper presents the results of a GPR feasibility study conducted on a drumlinized terrain in Cumbria, UK, where five drumlins were investigated using multiple radar antenna frequencies. The site was selected for the presence of nearby bedrock outcrops, suggesting a shallow drumlinized diamict–bedrock contact and a permeable lithology. Despite the clayey sediment and unfavourable weather conditions, a considerable penetration depth of ~12 m was achieved when using a 50 MHz antenna, with a separation of 1 m, trace spacing of 1 m and 128-fold vertical stack. Results indicate that the drumlinized diamict is in direct erosional contact with the bedrock. While the internal drumlin geometry is generally chaotic on the stoss side, evidence of layering dipping downflow at an angle greater than the drumlin surface profile was found on the lee side. The inter-drumlin areas comprise ~4 m of infill sediment that masks part of the original drumlin profile. Overall, this study indicates that GPR can be deployed successfully in the study of glacial bedform sedimentary architecture.

Introduced accidentally from South America, deeproot sedge is rapidly expanding in a variety of habitats throughout the southeastern United States. Of particular concern is its rapid expansion, naturalization, and formation of monocultures in Texas coastal prairie, one of the most imperiled temperate ecoregions in North America. The objective of this research was to examine how deeproot sedge responds to prescribed fire, to the herbicide imazapic, and to treatment combinations of both. Combinations of prescribed fire and imazapic treatments and imazapic-only treatments effectively reduced deeproot sedge cover and frequency. However, plots exposed to dormant season fires (with no imazapic) had greater deeproot sedge cover after burn treatments were applied, indicating that coastal prairie management using only dormant season prescribed fire will not work toward reduction or management of this exotic invasive species. Although deeproot sedge cover was often reduced in fire–imazapic treatment combinations, it was still present in treatment plots. Moreover, desirable functional plant groups (i.e., native bunchgrasses) did not respond positively to the fire–imazapic treatments, but in some instances, woody plant coverage increased. Repeated, long-term approaches using integrated and coordinated efforts with multiple treatment options will be necessary to restore community structure to desired compositional levels. Such integrated approaches should be effective in reducing deeproot sedge frequency, cover, and extent to more manageable levels throughout its introduced geographic range.

Native to temperate South America, deeproot sedge has naturalized throughout the southeastern United States. Often forming dense, homogenous stands, deeproot sedge has become widespread, invasive, and potentially harmful ecologically throughout the coastal prairie ecoregion of Texas. Possessing characteristics (rapid growth, generalized habitat requirements) of other weedy congeners (purple nutsedge and yellow nutsedge), its relatively recent expansion highlights the critical need to develop effective control techniques and strategies for this species throughout this endangered ecoregion. Research was performed to delineate total nonstructural carbohydrate (TNC) trends in deeproot sedge rhizomes for development of a phenologically based schedule for herbicide applications and mechanical treatments. Overall, TNC levels were greatest in May to August and lowest from October to January, regardless of study area. Apparently, deeproot sedge exerts little energy into seed production because TNC levels were continually replenished throughout the growing season. As such, foliar-herbicide application throughout the growing season should achieve total plant kill. Conversely, deeproot sedge rhizome TNC levels never fell below 30%, even during winter, which indicates that winter mechanical treatments or winter prescribed fires will not be effective because substantial rhizome reserves are present to support resprouting during the next growing season. Beyond a priori prevention, sequential herbicide applications combined with integrated, sequential, prescribed fire and herbicide treatments will be needed for long-term deeproot sedge control throughout its geographic range.

Hand-held hyperspectral reflectance data were collected in the summers of 2002, 2003, and 2004 to differentiate unique spectral characteristics of common turfgrass and weed species. Turfgrass species evaluated were: bermudagrass, ‘Tifway 419’; zoysiagrass, ‘Meyer’; St. Augustinegrass, ‘Raleigh’; common centipedegrass; and creeping bentgrass, ‘Crenshaw’. Weed species evaluated were: dallisgrass, southern crabgrass, eclipta, and Virginia buttonweed. Reflectance data were collected from greenhouse and field locations. An overall classification accuracy of 85% was achieved for all species in the field. A total of 21 spectral bands between 378 and 1,000 nm that were consistent over the three data collection periods were used for analysis. Only centipedegrass, zoysiagrass, and dallisgrass were correctly classified less than 80% of the time. An overall classification accuracy of 69% was achieved for the greenhouse species. Spectral bands used in this analysis ranged from 353 to 799 nm. Creeping bentgrass and Virginia buttonweed were classified correctly at 96 and 92%, respectively.

The Kulshan caldera formed at ∼1.15 Ma on the present-day site of Mt. Baker, Washington State, northwest USA and erupted a compositionally zoned (dacite-rhyolite) magma and a correlative eruptive, the Lake Tapps tephra. This tephra has previously been described, but only from the Puget Lowland of NW Washington. Here an occurrence of a Kulshan caldera correlative tephra is described from the Quaternary Palouse loess at the Washtucna site (WA-3). Site WA-3 is located in east-central Washington, ∼340 km southeast of the Kulshan caldera and ∼300 km east-southeast of the Lake Tapps occurrence in the Puget Lowland. Major- and trace element chemistry and location of the deposit at Washtucna within reversed polarity sediments indicates that it is not correlative with the Mesa Falls, Rockland, Bishop Ash, Lava Creek B or Huckleberry Ridge tephras. Instead the Washtucna deposit is related to the Lake Tapps tephra by fractional crystallisation, but is chemically distinct, a consequence of its eruption from a compositionally zoned magma chamber. The correlation of the Washtucna occurrence to the Kulshan caldera-forming eruption indicates that it had an eruptive volume exceeding 100 km3, and that its tephra could provide a valuable early-Pleistocene chronostratigraphic marker in the Pacific Northwest.

The collective response of electrons in an ultrathin foil target irradiated by an ultraintense (${\sim}6\times 10^{20}~\text{W}~\text{cm}^{-2}$) laser pulse is investigated experimentally and via 3D particle-in-cell simulations. It is shown that if the target is sufficiently thin that the laser induces significant radiation pressure, but not thin enough to become relativistically transparent to the laser light, the resulting relativistic electron beam is elliptical, with the major axis of the ellipse directed along the laser polarization axis. When the target thickness is decreased such that it becomes relativistically transparent early in the interaction with the laser pulse, diffraction of the transmitted laser light occurs through a so called ‘relativistic plasma aperture’, inducing structure in the spatial-intensity profile of the beam of energetic electrons. It is shown that the electron beam profile can be modified by variation of the target thickness and degree of ellipticity in the laser polarization.

White matter disruptions have been identified in individuals with congenital heart disease (CHD). However, no specific theory-driven relationships between microstructural white matter disruptions and cognition have been established in CHD. We conducted a two-part study. First, we identified significant differences in fractional anisotropy (FA) of emerging adults with CHD using Tract-Based Spatial Statistics (TBSS). TBSS analyses between 22 participants with CHD and 18 demographically similar controls identified five regions of normal appearing white matter with significantly lower FA in CHD, and two higher. Next, two regions of lower FA in CHD were selected to examine theory-driven differential relationships with cognition: voxels along the left uncinate fasciculus (UF; a tract theorized to contribute to verbal memory) and voxels along the right middle cerebellar peduncle (MCP; a tract previously linked to attention). In CHD, a significant positive correlation between UF FA and memory was found, r(20)=.42, p=.049 (uncorrected). There was no correlation between UF and auditory attention span. A positive correlation between MCP FA and auditory attention span was found, r(20)=.47, p=.027 (uncorrected). There was no correlation between MCP and memory. In controls, no significant relationships were identified. These results are consistent with previous literature demonstrating lower FA in younger CHD samples, and provide novel evidence for disrupted white matter integrity in emerging adults with CHD. Furthermore, a correlational double dissociation established distinct white matter circuitry (UF and MCP) and differential cognitive correlates (memory and attention span, respectively) in young adults with CHD. (JINS, 2015, 21, 22–33)