Effects of Leafy Spurge (Euphorbia esula) Infestation on Breeding Birds of the Sheyenne National Grassland, ND

Leafy spurge (Euphorbia esula) is an exotic invasive weed in the northern Great Plains. We examined the effects of leafy spurge infestation on densities and nest success of breeding birds in grasslands on the Sheyenne National Grassland (SNG), ND. We categorized spurge-infested grasslands into three levels of infestation, based on the area covered by spurge patches: (a) low (0-20%), (b) medium (20-60%) and, (c) high (\u3e 60%). We surveyed 60 100-m radius circular plots (20 in each category), and searched for nests in three 16-ha plots (one in each category). There were no statistically significant differences in mean species richness or mean species diversity among the three types of survey points. Of the eight most abundant grassland birds, only Upland Sandpiper (Bartramia longicauda) densities were significantly different among spurge categories, with highest mean density (13.5 ± 4.1 birds/100 ha) occurring on medium-spurge points. However, none of these species occurred in highest densities on high-spurge points. Le Conte\u27s Sparrows (Ammodramus leconteii) and Savannah Sparrows (Passerculus sandwichensis) were significantly negatively correlated with spurge infestation (-0.23 and -0.24, respectively). Spurge infestation was not correlated with grazing intensity (number of stems/m2: rs = -0.01; % cover: rs= -0.03). Le Conte\u27s Sparrows were negatively correlated (-0.34) with grazing intensity; whereas Savannah Sparrows were positively correlated with this factor (0.28). The low-spurge plot contained the most nests (n = 24), but nests on the high-spurge plot (n = 11) experienced the highest nest success (0.745, χ2 = 13.2, df = 2, P \u3c 0.01). There were no significant differences between successful and unsuccessful nests or between nests and nearby paired sites with respect to number of spurge stems/m2 or percent cover of spurge. However there were significant differences for other measured vegetational features. Thus, based on these data, most birds appeared to show little response to leafy spurge per se. Birds may choose microhabitats based more on characteristics of vegetation structure (e.g. ground cover, vegetation height, vertical density, litter depth) than on particular plant species. Circumstantial evidence suggests that spurge may even provide benefits for certain species through foraging opportunities and nest protection. Assuming spurge can alter vegetation structure to the detriment of grassland birds, infestation may not be high enough over much of the SNG to show a strong negative effect on bird community parameters. Other factors may obscure relationships between bird densities and spurge infestation including strong avian preferences for other vegetation characteristics, cattle grazing intensity, and habitat productivity. We surveyed the breeding bird communities of the five major habitat types (grassland, sedge meadow, wetland, savanna, and woodland) of the SNG. Grasslands contained the greatest number of total species (47), but species richness/point and species diversity/point were not significantly different among habitat types (F = 1.33, P = 0.29; F = 0.65, P 0.63, respectively). The most abundant species on grassland survey points was the Western Meadowlark (47.5 birds/100 ha). The Red-winged Blackbird was the most abundant species on sedge meadow and wetland survey points (88.5 and 382.2 birds/100 ha, respectively). Ground foragers were the most abundant guild on savanna and woodland points (236.6 and 229.3 birds/100 ha, respectively). The complex interspersion among habitat patches, combined with the relatively broad range of habitat preferences and flexibility displayed by many bird species probably lead to the observed patterns of species overlap among communities

Optimizing cardiovascular and chemopreventive benefits of aspirin: what role for the proton-pump inhibitors?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75584/1/j.1365-2036.2004.02347.x.pd

Out-Life Characteristics of IM7/977-3 Composites

The capability to manufacture large structures leads to weight savings and reduced risk relative to joining smaller components. However, manufacture of increasingly large composite components is pushing the out-time limits of epoxy/ carbon fiber prepreg. IM7/977-3 is an autoclave processable prepreg material, commonly used in aerospace structures. The out-time limit is reported as 30 days by the manufacturer. The purpose of this work was to evaluate the material processability and composite properties of 977-3 resin and IM7/977-3 prepreg that had been aged at room temperature for up to 60 days. The effects of room temperature aging on the thermal and visco-elastic properties of the materials were investigated. Neat resin was evaluated by differential scanning calorimetry to characterize thermal properties and change in activation energy of cure. Neat resin was also evaluated by rheometry to characterize its processability in composite fabrication. IM7/977-3 prepreg was evaluated by dynamic mechanical analysis to characterize the curing behavior. Prepreg tack was also evaluated over 60 days. The overall test results suggested that IM7/977-3 was a robust material that offered quality laminates throughout this aging process when processed by autoclave

Low-melt Viscosity Polyimide Resins for Resin Transfer Molding (RTM) II

A series of polyimide resins with low-melt viscosities in the range of 10-30 poise and high glass transition temperatures (Tg s) of 330-370 C were developed for resin transfer molding (RTM) applications. These polyimide resins were formulated from 2,3,3 ,4 -biphenyltetracarboxylic dianhydride (a-BPDA) with 4-phenylethynylphthalic anhydride endcaps along with either 3,4 - oxyaniline (3,4 -ODA), 3,4 -methylenedianiline, (3,4 -MDA) or 3,3 -methylenedianiline (3,3 -MDA). These polyimides had pot lives of 30-60 minutes at 260-280 C, enabling the successful fabrication of T650-35 carbon fiber reinforced composites via RTM process. The viscosity profiles of the polyimide resins and the mechanical properties of the polyimide carbon fiber composites will be discussed

GaAs Photovoltaics on Polycrystalline Ge Substrates

High efficiency III-V multijunction solar cells deposited on metal foil or even polymer substrates can provide tremendous advantages in mass and stowage, particularly for planetary missions. As a first step towards that goal, poly-crystalline p/i/n GaAs solar cells are under development on polycrystalline Ge substrates. Organo Metallic Vapor Phase Epitaxy (OMVPE) parameters for pre-growth bake, nucleation and deposition have been examined. Single junction p/i/n GaAs photovoltaic devices, incorporating InGaP front and back window layers, have been grown and processed. Device performance has shown a dependence upon the thickness of a GaAs buffer layer deposited between the Ge substrate and the active device structure. A thick (2 m) GaAs buffer provides for both increased average device performance as well as reduced sensitivity to variations in grain size and orientation. Illumination under IR light (lambda > 1 micron), the cells showed a Voc, demonstrating the presence of an unintended photoactive junction at the GaAs/Ge interface. The presence of this junction limited the efficiency to approx.13% (estimated with an anti-refection coating) due to the current mismatch and lack of tunnel junction interconnect

Randomised controlled trial of video clips and interactive games to improve vision in children with amblyopia using the I-BiT system

Background Traditional treatment of amblyopia involves either wearing a patch or atropine penalisation of the better eye. A new treatment is being developed on the basis of virtual reality technology allowing either DVD footage or computer games which present a common background to both eyes and the foreground, containing the imagery of interest, only to the amblyopic eye. Methods A randomised control trial was performed on patients with amblyopia aged 4–8 years with three arms. All three arms had dichoptic stimulation using shutter glass technology. One arm had DVD footage shown to the amblyopic eye and common background to both, the second used a modified shooter game, Nux, with sprite and targets presented to the amblyopic eye (and background to both) while the third arm had both background and foreground presented to both eyes (non-interactive binocular treatment (non-I-BiT) games). Results Seventy-five patients were randomised; 67 were residual amblyopes and 70 had an associated strabismus. The visual acuity improved in all three arms by approximately 0.07 logMAR in the amblyopic eye at 6 weeks. There was no difference between I-BiT DVD and non-I-BiT games compared with I-BiT games (stated primary outcome) in terms of gain in vision. Conclusions There was a modest vision improvement in all three arms. Treatment was well tolerated and safe. There was no difference between the three treatments in terms of primary stated outcomes but treatment duration was short and the high proportion of previously treated amblyopia and strabismic amblyopia disadvantaged dichoptic stimulation treatment

The Cystic Duct Remnant: An Unusual Case of a Biliary Intraluminal Filling Defect

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72892/1/j.1572-0241.1988.tb06086.x.pd

Visual function, traumatic brain injury, and posttraumatic stress disorder

Traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD) are signature injuries of the Iraq and Afghanistan conflicts. The conditions can be comorbid and have overlapping signs and symptoms, making it difficult to diagnose and treat each. TBI is associated with numerous changes in vision function, but vision problems secondary to PTSD have not been documented. To address this shortcoming, we reviewed the medical records of 100 patients with a history of TBI, noting PTSD diagnoses, visual symptoms, vision function abnormalities, and medications with visual side effects. Forty-one patients had PTSD and 59 did not. High rates of binocular vision and oculomotor function deficits were measured in patients with a history of TBI, but no significant differences between patients with or without PTSD were evident. However, compared to patients without PTSD, patients with PTSD had more self-reported visual symptoms in all four assessments and the complaint rates were significantly higher for light sensitivity and reading problems. Together, these findings may be beneficial in understanding vision problems in patients with TBI and PTSD as comorbid conditions compared with those with TBI alone