Vibration and Instability of Plate-Assemblies including Shear and Anisotropy (VIPASA) user's guide, addendum

Extensions developed at Langley Research Center to the VIPASA computer program are described including a procedure for simple thermal stress analysis and options for graphical display of output. Input requirements for operation of the modified program are given in detail

Fabrication and characterizations of proton-exchanged LiNbO3 waveguides fabricated by inductively coupled plasma technique

This Letter reports the use of an inductively coupled plasma technique for fabrication of proton-exchanged (PE) LiNbO3 (LN) waveguides. Planar and stripe waveguides have been formed in Y-cut LN which are difficult to obtain with the conventional molten acid method due to the occurrence of surface damage. Secondary ion mass spectrometry, scanning electron microscopy, and infrared absorption spectrum characterization results revealed that a uniform vertical PE profile with a single low order crystal phase has been directly obtained as a result of this unique process. X-ray photoelectron spectroscopy characterization of the treated surface revealed the existence of NbO as the cause for a sometimes darkened surface and confirms the ability to completely restore the surface to LN by oxygen plasma treatment. Atomic force microscopy measurement confirms that good surface quality has been maintained after regeneration of the surface to LN

Precalving Distribution and Abundance of Barren-Ground Caribou on the Northeastern Mainland of the Northwest Territories

An aerial survey with about 5% coverage of the northeastern mainland, Northwest Territories (342,000 sq. km.) was conducted 5-10 May 1983. We estimated there were 120,000 ± 13,900 caribou (0.35 ± 0.041 caribou/sq km) in the study area. Mean caribou group size ranged from 6 to 11 among nine strata and was correlated (r = 0.81) with stratum caribou density. We found four regions of high caribou density. Three regions coincided with the calving grounds of previously defined herds, the Melville, Wager, and Lorillard, and the fourth suggests a discrete population in the previously unsurveyed area south of the Queen Maud Gulf.Key words: caribou, aerial survey, Rangifer, distribution, abundance, northeastern Northwest TerritoriesMots clés: caribou, inventaire aérien, Rangifer, distribution, abondance, nord-est des Territoires du Nord-Oues

First Report of the Alfalfa Blotch Leafminer (Diptera: Agromyzidae), and Selected Parasites (Hymenoptera: Eulophidae) in Minnesota and Wisconsin, USA

Alfalfa blotch leafminer, Agromyza frontella, has been a serious pest of alfalfa, Medicago sativa, in the northeastern U.S. and in eastern Ontario, Canada. Until recently, the western edge of the A. frontella distribution in the U.S. was limited to eastern Ohio. We document for the first time, the occurrence of A. frontella in Minnesota and Wisconsin. Alfalfa stems damaged by A. frontella, based on adult feeding punctures, obvious blotched leafmining or the presence of larvae, were first found in 3 northern Minnesota coun­ties during October, 1994. Infested counties included Lake of the Woods, Cook and Lake, all bordering western Ontario, Canada. In 1995, A. frontella was again found in Cook and Lake counties, where 99-100% of the stems, and 18-35% of the trifoliates/stem, contained larvae or exhibited obvious feeding damage. In 1996, following a more expanded survey, a total of 11 and 5 counties, in Minnesota and Wisconsin, respectively, showed some level of A. frontella feeding damage (stem samples ranged from \u3c5 to 100% infested). Based on additional counties surveyed 11 October, 1996, where A. frontella was not found, we now have a reasonable estimate of the southern edge of the distribution in Minnesota and Wisconsin. A total of 2 and 6 A. frontella adults were identified from sweep-net samples taken from fields with obvious feeding damage during 1995 (Lake Co.) and 1996 (Cook Co,), respectively. Three eulophid (Hymenoptera) parasites were reared from A. frontella-infested alfalfa stems collected during October, 1994 in Cook Co., Minn., including: Diglyphus begini, D. pulchripes, and Diglyphus sp., prob. isaea, all of which are new records. Our hypothesis is that A. frontella moved into Minnesota from Ontario Canada, via alfalfa hay purchased by northern Minnesota growers

One-year clinical results of restorations using a novel self-adhesive resin-based bulk-fill restorative.

This prospective study assessed the dual-curing self-adhesive bulk-fill restorative Surefil one. The restorations were placed and reviewed by dental practitioners who are members of a practice-based research network in the United States. Seven practitioners filled 60 cavities (20 class I, 19 class II and 21 class V) in 41 patients with Surefil one without adhesive, according to the manufacturer's instructions. The restorations were evaluated using modified USPHS criteria at baseline, 3 months, and 1 year. Patients were also contacted to report postoperative hypersensitivity one to four weeks after placement. The only patient that showed moderate hypersensitivity after 1 year had previously reported symptoms that were unlikely associated to the class I molar restoration. One class II restoration in a fractured maxillary molar was partially lost. The remaining restorations were found to be in clinically acceptable condition resulting in an annual failure rate of 2%. Color match showed the lowest number of acceptable scores (88%) revealing significant changes over time (P = 0.0002). No significant differences were found for the other criteria (P > 0.05). The novel self-adhesive bulk-fill restorative showed clinically acceptable results in stress-bearing class I and II as well as non-retentive class V cavities at 1-year recall

Mental health and wellbeing of postgraduate researchers: exploring the relationship between mental health literacy, help-seeking behaviour, psychological distress, and wellbeing.

Studies of Postgraduate Researchers (PGRs) have highlighted that the population may be at risk of developing symptoms of common mental health problems. Early intervention and preventative measures may reduce this risk, such as improving mental health literacy (MHL). However, it is unclear what the relationship is between MHL and outcomes such as help-seeking behaviour, psychological distress and wellbeing, in PGRs. Therefore, the current study aimed to explore this relationship. A secondary aim of this study was to compare data collected from PGRs with undergraduate students. Two hundred and forty-one PGRs from two universities in England completed an anonymous online quantitative survey, with PGRs reporting on their MHL, help-seeking behaviour, psychological distress, and wellbeing, in addition to demographic and academic characteristics. Results indicated that 70% of PGRs were experiencing symptoms categorised as mild to severe psychological distress. Stepwise multiple regressions revealed that lower levels of wellbeing predicted higher levels of distress and lower levels of help-seeking behaviour. Compared with undergraduate students, PGRs in this study reported higher levels of psychological distress compared to undergraduate students, after adjusting for age, sex, and previous diagnosis of a mental health problem, as well as MHL, after adjusting for sex and previous diagnosis (p 0.05). Study findings suggest that PGRs, at the start of the academic year, are distressed and may not be seeking appropriate help for their concerns. Further studies should explore the environmental factors that may exacerbate mental health concerns beyond that associated with a challenging degree, within the PGR population

Mobile work station concept for assembly of large space structures (zero gravity simulation tests)

The concept presented is intended to enhance astronaut assembly of truss structure that is either too large or complex to fold for efficient Shuttle delivery to orbit. The potential of augmented astronaut assembly is illustrated by applying the result of the tests to a barebones assembly of a truss structure. If this structure were assembled from the same nestable struts that were used in the Mobile Work Station assembly tests, the spacecraft would be 55 meters in diameter and consist of about 500 struts. The struts could be packaged in less than 1/2% of the Shuttle cargo bay volume and would take up approximately 3% of the mass lift capability. They could be assembled in approximately four hours. This assembly concept for erectable structures is not only feasible, but could be used to significant economic advantage by permitting the superior packaging feature of erectable structures to be exploited and thereby reduce expensive Shuttle delivery flights

Cosmology with positive and negative exponential potentials

We present a phase-plane analysis of cosmologies containing a scalar field $\phi$ with an exponential potential $V \propto \exp(-\lambda \kappa \phi)$ where $\kappa^2 = 8\pi G$ and $V$ may be positive or negative. We show that power-law kinetic-potential scaling solutions only exist for sufficiently flat ($\lambda^26$) negative potentials. The latter correspond to a class of ever-expanding cosmologies with negative potential. However we show that these expanding solutions with a negative potential are to unstable in the presence of ordinary matter, spatial curvature or anisotropic shear, and generic solutions always recollapse to a singularity. Power-law kinetic-potential scaling solutions are the late-time attractor in a collapsing universe for steep negative potentials (the ekpyrotic scenario) and stable against matter, curvature or shear perturbations. Otherwise kinetic-dominated solutions are the attractor during collapse (the pre big bang scenario) and are only marginally stable with respect to anisotropic shear.Comment: 8 pages, latex with revtex, 9 figure

Prioritisation of weed species relevant to Australian livestock industries for biological control

Classical biological control is the only realistic option for managing many of the most serious weeds affecting livestock industries in Australia. This project developed and applied a framework, based on a matrix assessment system, to prioritise biocontrol efforts using new agents against 79 weed taxa. These taxa were identified in a concurrent project as priorities for Research, Development and Extension to address weed problems of Australian livestock industries. The framework considered the current and potential impacts of the weeds versus prospects for biocontrol. The latter combined assessments of feasibility of undertaking a biocontrol program that would yield host-specific agents, and the likelihood that agents would be successful in mitigating the impacts of the weeds once released in Australia. Each categorisation was supported with a written rationale that explained the ranking assigned and captured uncertainties. Key investment areas for future actions to address biocontrol knowledge gaps for each weed were identified. Twenty-one weeds with the highest combined rankings for biocontrol prospects and current and/or potential impacts were shortlisted as priority taxa for future investment. Results provide the best available information for funding agencies responsible for RD&E for livestock industries to make investment decisions across their weed biocontrol portfolio