37 research outputs found
Comparing bird communities within shrubby transmission line rights-of-way managed by mowing or by selective herbicide application in Maine and New Hampshire
In the northeastern U.S., thousands of miles of shrub-dominated transmission line rights-of-way (ROW) extend across the landscape and provide some of the largest and most stable shrubland habitats in the region. These ROW are used as nesting and post-fledging habitat by the regionâs entire community of shrubland-dependent songbirds, but evidence for how ROW are used by songbirds that require other habitats for nesting is lacking. Mist-netting surveys conducted in regenerating clearcuts indicate that adult and fledgling mature-forest songbirds comprise a large proportion of the bird community in clearcuts during the post-fledging portion of the breeding season, a time when juvenile birds and molting adults require dense cover to avoid predators and abundant food resources to prepare for migration. In 2017, we began the first comprehensive mist-netting survey ever conducted in shrubby ROW in southern Maine and New Hampshire to inventory the entire community of songbirds using ROW during the nesting and post-fledging periods. In this preliminary year of our study, we investigated whether differences in the height, density, and species composition of plants between three ROW maintained by mowing and three ROW maintained with selective herbicide treatment resulted in differences in the community of shrubland-dependent or other-habitat-dependent songbirds. We conducted six mist net surveys in each ROW from late May-late August and captured 1,153 individual birds of 44 unique species. There was no difference in the richness or diversity of âShrubland Species,â âOther Species,â or the entire songbird community between the different ROW types
Familial influences of anxiety in youngsters
This study sought to determine the degree to which various family factors correlate with child anxiety. Fifty-nine subjects, aged 12 through 18, completed the Revised Children\u27s Manifest Anxiety Scale. Parents of these children completed the Family Environment Scale, the Locke-Wallace Marital Adjustment Test, and the State-Trait Anxiety Inventory for Adults. Results indicated that maternal level of anxiety was the only familial factor that was significantly correlated with child anxiety. There was a non-significant but noteworthy negative correlation between child anxiety and the independence subscale of the Family Environment Scale. Based on these findings, recommendations for prevention, assessment, and treatment are made. Limitations of this study and suggestions for future research are outlined
Computational mechanical analysis of composite bondlines under environmental moisture loads
AbstractA combined moisture diffusion and mechanical computational analysis methodology was developed as part of an independent research program at Lockheed to enhance our understanding of nonlinear and coupled physical processes in materials. The physical behavior of interest is the mechanical response of composite material systems to environmental conditions which can change the materials' moisture content. In particular, it is desirable to know what set of environmental conditions will affect the integrity of a partial adhesive bondline when a bondline gap (no adhesive) is present. The Lockheed proprietary finite element analysis code DIAL was modified to analyze this phenomena in two stages. First, the temporal moisture partial pressures in the materials are calculated from initial and environmental boundary conditions and second, these partial pressures are then passed to a quasi-static mechanical analysis where the moisture data at each time step is treated as a dilatation (swelling) load. The resulting stress and strain state is then calculated, as well as gap closure, if any.Demonstration of this methodology was on a relatively simple 2-dimensional axisymmetric example problem. The results show primarily compressive stresses caused by the positive dilatation (swelling) induced by moisture intrusion of the structure. The stresses concentrate at adhesive bondlines, and bondline gap behavior (i.e., the absence of a contiguous adhesive bond at material interfaces) is correctly simulated. It should be noted that the behavior of the gap and any resultant stress/strains due to a change in moisture is problem dependent, and this example problem is meant as a demonstration of methodology
Ground-state ammonia and water in absorption towards Sgr B2
We have used the Odin submillimetre-wave satellite telescope to observe the
ground state transitions of ortho-ammonia and ortho-water, including their 15N,
18O, and 17O isotopologues, towards Sgr B2. The extensive simultaneous velocity
coverage of the observations, >500 km/s, ensures that we can probe the
conditions of both the warm, dense gas of the molecular cloud Sgr B2 near the
Galactic centre, and the more diffuse gas in the Galactic disk clouds along the
line-of-sight. We present ground-state NH3 absorption in seven distinct
velocity features along the line-of-sight towards Sgr B2. We find a nearly
linear correlation between the column densities of NH3 and CS, and a
square-root relation to N2H+. The ammonia abundance in these diffuse Galactic
disk clouds is estimated to be about (0.5-1)e-8, similar to that observed for
diffuse clouds in the outer Galaxy. On the basis of the detection of H218O
absorption in the 3 kpc arm, and the absence of such a feature in the H217O
spectrum, we conclude that the water abundance is around 1e-7, compared to
~1e-8 for NH3. The Sgr B2 molecular cloud itself is seen in absorption in NH3,
15NH3, H2O, H218O, and H217O, with emission superimposed on the absorption in
the main isotopologues. The non-LTE excitation of NH3 in the environment of Sgr
B2 can be explained without invoking an unusually hot (500 K) molecular layer.
A hot layer is similarly not required to explain the line profiles of the
1_{1,0}-1_{0,1} transition from H2O and its isotopologues. The relatively weak
15NH3 absorption in the Sgr B2 molecular cloud indicates a high [14N/15N]
isotopic ratio >600. The abundance ratio of H218O and H217O is found to be
relatively low, 2.5--3. These results together indicate that the dominant
nucleosynthesis process in the Galactic centre is CNO hydrogen burning.Comment: 10 pages, 5 figure
âWhat shall these bowes do?â : the gift and its violence in A Gest of Robyn Hode
This essay proposes that gift exchange in Middle English tales of outlawry serves to negotiate problems of violence and social conflict endemic to late medieval England. Repeated scenes of giving reaffirm âfellowshipâ as an oft-noted ideal of this literature, but gifts also work as a form of symbolic violence, suggesting that coercion is the not-so-hidden basis of community here. Seemingly part and parcel of the outlaw heroâs rebellious appeal, his generosity turns out to serve a surprisingly conservative function. Yet this conservative message is not strictly a matter of feudal nostalgia. In fact, reading the logic of the gift in these tales allows us to move beyond the long-standing debate over their economic ideology. Neither purely feudal nor mercantile in their function, the outlawâs gifts constitute a form of violence whose appeal lies precisely in its forceful resolution of conflicting economic and social interests. The relatively popular A Gest of Robyn Hode (after 1450) provides the clearest example of how generosity intersects in outlaw literature with anxieties about violence and social order. Like its analogues, the Gest testifies to the survival of the gift as a fantasy of order in an emergently modern world
Application of the finite-element method to the diffusion and reaction of chemical species in multilayered polymeric bodies
Ab initio study of the interaction of polyoxymethylene with polyoxymethylene, ammonium perchlorate, and the aluminum (100) surface
Self-consistent restricted and unrestricted Hartree-Fock calculations have been performed for the microscopic interactions in particle-filled polymeric suspensions. First, we have investigated the elongation and the torsion potential of a single infinite polyoxymethylene chain. It is found that the 9/5 helix is 4.5 kcal/mol lower in energy than the planar zigzag conformation. A Youngs modulus of 8020 GPa is obtained for the chain-direction deformation. The potential-energy curve for the van der Waals interaction between two 2/1 helical polyoxymethylene chains has a minimum for a chain separation of 4.3 A with a binding energy of 1.3 kcal per (CH2O)2 translational unit. For the chain-direction slip of two polyoxymethylene chains a barrier of 5.1 kcal is calculated. To study polymer-particle interactions, cluster calculations for the interaction of polyoxymethylene fragments with ammonium perchlorate and the aluminum (100) surface have been performed. The oxygen in the polyoxymethylene backbone forms a hydrogen bond with ammonium perchlorate. For an O-H distance of 1.62 A a binding energy of 23.7 kcal is obtained. This strong coordination of the ammonium ion with the oxygen in the polyether backbone is in agreement with the experimentally observed increase in viscosity of polyether lacquers upon dissolution of ammonium perchlorate. The potential energy curve for the bonding of a H3C-O-CH2-O-CH2-O-CH3 fragment at the on-top sites of an Al5 cluster has a minimum for an O-Al separation of 2.3 A with a binding energy of 17.1 kcal (8.55 kcal per O-Al bonding). This binding energy is of the same order of magnitude as the energy of 4.5 kcal per CH2O unit needed to stretch the polyoxymethylene 9/5 helix to a helix whose next-nearest oxygen atoms are commensurate with the aluminum lattice constant of 4.05 A. Therefore the coating of aluminum particles with polyoxymethylene polymers is possible. The quantum-mechanical results of these microscopic static-model studies provide an estimate for polymer-particle forces needed for a macroscopic dynamic model of particle-filled polymeric suspensions. © 1988 The American Physical Society
A Microsoft Fortran 77 Program For Testing The Differences Among Independent First-Order Partial Correlations
A Microsoft FORTRAN 77 program is presented that computes a global test and the subsequent multiple range procedure for testing differences among independent first-order partial correlations. © 1995, Sage Publications. All rights reserved
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