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A new species of Chingia, known only from Vanikoro in the Solomon Islands, is described and illustrated. It is distinctive in having flat, thickened, tortuous stipe scales. It is most closely related to an accession of Chingia clavipilosa from Mount Kinabalu, from which it is distinguished by its lack of hyaline acicular hairs on the abaxial laminar axes. Other Chingia species in the Solomon Islands are distinguished by having abundant stiff, terete stipe scales.

Males often broadcast conspicuous signals from within mixed-species aggregations to attract mates. In addition to attracting females, however, these displays expose signalers to eavesdropping preda...

Deworming horses with anthelmintics that have activity against encysted small strongyle larvae (L(3) and L(4)) is a common practice in parasite control programs. The two drugs currently available for this use are moxidectin (MOX) administered in a single dose of 0.4 mg/kg and fenbendazole (FBZ) given at the larvicidal dose (10mg/kg for 5 days). Here, we report the efficacy of MOX and the larvicidal dose of FBZ for reducing counts of strongyle-type eggs per gram of feces in naturally infected horses. Fecal egg counts (FECs) of 15 yearlings were observed following deworming. On day 0, 6 of the 15 yearlings were administered a larvicidal dose of FBZ; 14 days later, all 15 yearlings received MOX at a single dose of 0.4 mg/kg. Feces were collected on day 0 for pre-treatment egg counts. Feces were collected at weekly intervals thereafter during FEC observation periods. FECs of FBZ-treated horses were compared at day 0 and 14 days post-treatment. The difference in means pre- and post-treatment with FBZ was not statistically significant (p=0.65). On days 0 and 42 of the MOX treatment observation period the mean FEC of the yearlings that had not received the FBZ treatment did not differ significantly from that of the FBZ-treated yearlings. MOX was effective in reducing fecal egg counts to 0 EPG for 21 days. At day 35 all but 2 of the yearlings had some eggs present (range=4-361 EPG) and at day 42 all but 1 yearling had eggs present (range=3-432 EPG). At day 42 the group mean FEC reduction had fallen from 100% to 67%. Results of this study do not support the use of the larvicidal dose of FBZ for small strongyle control. Larger field studies will be needed to investigate whether egg reappearance periods are shortening for MOX-treated horses.

In this paper, results from an experimental study of the natural and forced evolution of a pair of counter rotating wing-tip vortices are reported. The vortices were generated using a pair of opposed wing-tips in a wind tunnel and measurements made up to 77 tip-spacings downstream of the models at a chord Reynolds number of 1.3 × 105. The wake was interrogated using 2D particle image velocimetry and the long-wave Crow instability observed. Velocity data were recorded throughout the lifetime of the instability from initial growth through linking, formation of vortex rings and their subsequent decay. Forcing was achieved using pulsed air jets blowing in the span-wise direction from the wing tip and imparting spatially periodic perturbations to the vortices. Forcing at a frequency within the range amplified by the Crow instability was found to enhance the instability growth rate whereas forcing at a frequency outside the amplified range was found to inhibit instability growth. In the latter case the imparted wavelength was observed to die out with a preferred wavelength growing in its place.

Naturally occurring instabilities such as the long wave Crow instability are one of the mechanisms that can bring about the break-up of aircraft wake vortex pairs. Encouraging the early onset of such instabilities by active or passive means offers the possibility of accelerating wake break-up and dissipation with favourable consequences in terms of safe aircraft separation and airport capacity. This paper describes an experimental investigation of the evolution of the Crow instability in a counter rotating vortex pair perturbed by a pulsed air sheet. Flow measurements were made using two-dimensional particle image velocimetry and two methods devised to detect wake break-up from the two-dimensional data. Pulsed excitation at a wavelength within the range amplified by the Crow instability resulted in wake break-up and the formation of vortex rings at a downstream distance reduced by up to 37% compared to the baseline case. For excitation at a wavelength outside the excited range early break-up was also observed but the extent of the accelerated break-up was reduced as the amplitude of the excitation was increased.

The vortex wake hazard associated with transport aircraft is well known. One strategy for its alleviation is to alter the near field wake topology to distribute circulation over an increased area and reduce the consequent rolling moment on a following aircraft encountering the wake. The paper describes the results of an experimental investigation of the use of supplementary vortex generators to modify the tip vortex shed from a half-span airfoil. The experiments were conducted in a small low speed wind tunnel at a chord Reynolds number of 2.2 × 10 5 and the flow was characterised by measurement of the instantaneous and mean cross-stream flow field using particle image velocimetry. The results show that when the vortex generator is configured to produce a vortex that is co-rotating with respect to the wing-tip vortex, the two merge within five chord-lengths of the trailing edge resulting in a vortex with increased size relative to that of the baseline wake. Various vortex generator geometries were tested. A semi-circular generator produced an increase in core radius by a factor of five but the best shape was deemed triangular since generators of this shape produced substantial vortex enlargement with relatively low lift penalty. Low slenderness ratio generators were also deemed preferable since for a high slenderness generator it was shown that merging failed due to a negative vorticity buffer constrained to the region between the tip and generator vortex by the proximity of the generator vortex to the wing surface. Increasing the generator angle of attack was shown to increase the effectiveness of circulation redistribution. At the highest angles of attack increases occurred despite a decrease in VG vortex strength due to stalling. Unsteadiness in the stalled VG flow appears to enhance vorticity diffusion and it is hypothesised that it may also initiate cooperative instabilities in multiple vortex systems.

The separation distance required between transport aircraft to avoid wake vortices remains a limiting factor on airport capacity. The dissipation of the wake can be accelerated by perturbing co-operative instabilities between multiple pairs of vortices. This paper presents the results of a preliminary experimental investigation into the use of pulsed span-wise air jets in the wing tip to perturb a single tip vortex in the very near field. Velocity measurements were made using PIV and hot-wire anemometry. The results demonstrate that the vortex position can be modulated at frequencies up to 50 Hz and, as such, the method shows promise for forcing instability in multiple vortex wakes.

Cryogenic air separation technology has been successfully employed for many years to supply oxygen for the gasification of a wide range of hydrocarbon feedstocks to generate synthesis gas for the production of fuels, chemicals and other valuable products. Examples include the conversion of liquid and solid refinery waste streams into hydrogen for use within the refinery along with the coproduction of electricity, and the growing interest in gas-to-liquids (GTL) processes which convert natural gas into synthetic crude oil, waxes and fuels. Recently, increased attention has been focused on methods of integrating the oxygen production process with the downstream hydrocarbon processing units to reduce facility cost or increase efficiency. A review of traditional and developing processes to generate oxygen is presented, along with integration schemes to improve the economics of these facilities.

The article is a collection of reminiscences that capture some of the spirit of the past days of computer graphics.

We present an overview of the Long Duration Exposure Facility (LDEF) induced activation measurements. The LDEF, which was gravity-gradient stabilized, was exposed to the low Earth orbit (LEO) radiation environment over a 5.8 year period. Retrieved activation samples and structural components from the spacecraft were analyzed with low and ultra-low background HPGe gamma spectrometry at several national facilities. This allowed a very sensitive measurement of long-lived radionuclides produced by proton- and neutron-induced reactions in the time-dependent, non-isotropic LEO environment. A summary of major findings from this study is given that consists of directionally dependent activation, depth profiles, thermal neutron activation, and surface beryllium-7 deposition from the upper atmosphere. We also describe a database of these measurements that has been prepared for use in testing radiation environmental models and spacecraft design.

Introduction I N wind-tunnel-based experimental aerodynamic projects a substantial proportion of project resources in terms of both time and cost is consumed by the design and manufacture of wind-tunnel models. This can limit the scope of experiments and cause long lead times. Thus, methods that can expedite the model-building process are highly beneficial. The manufacture of wind-tunnel models has traditionally been a highly skilled and time-consuming process.1 By their nature aerodynamic bodies can have complex three-dimensional curvature and often the experiment requires internal details such as the provision for surface-pressure tappings. Thus, wind-tunnel models are often constructed from a number of parts, which require accurate fitting and hand finishing to obtain the necessary high surface finish. Ideally, the wind-tunnel experiment is an integral part of the design process, which may call for a prescribed range of model configurations to be tested, or alternatively for the iterative optimization of a particular feature of the model. In the former case the range of configurations that can be tested is limited by the cost of each model and in the latter case by the speed at which a model feature can be changed. A number of studies2−5 have demonstrated the advantages of rapid prototyping techniques for building wind-tunnel models in speed and cost relative to traditional techniques. Dimensional tolerances and surface finish may be inferior, which in turn increases experimental uncertainty, but nevertheless the method is quite adequate for preliminary studies. In this Note we outline the use of rapid prototyping for producing wind-tunnel models with internal features. A most advantageous aspect of the rapid-prototyping method is the ability to produce internal forms, that would be difficult to design and manufacture by traditional techniques. Rapid-prototyping technology is reviewed briefly in context and two case studies from the work of the authors are presented.

The Northeast Proton Therapy Center (NPTC) is currently being designed and is scheduled for completion in 1998. The goal of the project is to provide the northeast region of the United States with a first class proton therapy facility which has the capabilities needed for the conduct of innovative research, and proven treatments using proton therapy. The NPTC will be built on the Massachusetts General Hospital (MGH) campus. MGH has contracted Bechtel Corporation to coordinate the design and building of the civil construction. Ion Beam Applications (IBA) who is teamed with General Atomics, is responsible for the equipment. The specifications for the facility are written in terms of the clinical performance requirements and will be presented. Aspects of the facility design, status and plans will also be presented.

Rye House power station near Hoddesdon in Hertfordshire, the second of PowerGen's combined-cycle gas turbine plants built by Siemens, was officially opened in April 1994. This article takes a brief look at this increasingly important power generating technology and its application at Rye House. The authors discuss many of the technical aspects of Rye House. These include fuel supplies, heat recovery, steam turboset, steam condensing system, generation system, electrical system, power station control, thermal performance and environmental considerations. Project management aspects are also discussed.

Aging is the single largest risk factor for cardiovascular diseases, which in turn are the leading cause of death of individuals over the age of 65 years. In part, this risk is due to a profound loss of vasomotor function of the major conduit arteries, primarily because of lower levels of endothelial-derived nitric oxide. The mechanisms involved in vascular dysfunction are not entirely understood, but age-related alterations in eNOS (endothelial nitric oxide synthase) activity appear to be a likely source of the aging lesion. However, age-related changes in cell signalling that ultimately affect eNOS phosphorylation and its activity have not been explored. Results in our laboratory indicate that levels of eNOS phosphorylation in aortas from aged F344×BN rats (28–30 months old) are almost 50% lower than in aortas from young animals (3 months old). Lower eNOS phosphorylation is directly attributable to loss of constitutive Akt/protein kinase B activity. The decline in eNOS phosphorylation can be partially restored by treating old rats with (R)-α-lipoic acid. These results thus suggest that age-related changes in eNOS phosphorylation may be a significant factor in the overall loss of vasomotor function in the elderly.

(1993). Mental Health Services in New Zealand. International Journal of Mental Health: Vol. 22, Mental Health Care in the Western Pacific Region, pp. 87-100.

In 1991-92, Neisseria meningitidis group C was isolated from the blood of eight students in Urbana, Illinois, USA, and from the cerebrospinal fluid of one student from a nearby community, Decatur, Illinois. These and other bacterial species were analysed by PCR fingerprinting using primers selected from the ribosomal (r)DNA loci. A rDNA primer pairs spanning a region within the 16S rDNA amplified a predicted 280 base pair (bp) DNA fragment from Neisseria spp. and fragments of different sizes for other genera. This primer pair specifically detected a carrier of N. meningitidis in a small clinical battery. Identify of the fragment was confirmed by restriction endonuclease analysis. A 600 bp fragment was also amplified from the 16S-23S internal transcribed spacer (ITS) of N. meningitidis ; amplification from six other genera yielded different-sized fragments. Digestion of the ITS fragment from N. meningitidis with Alu I revealed three patterns; pattern I was found only for serogroup C isolates, and it was the dominant pattern among recent isolates with the exception of the one from Decatur. The isolate from Decatur yielded pattern III which suggested a non-clonal relationship to the seven isolates from Urbana. Patterns II and III were more prevalent in isolates from the 1960's and 1980's. PCR-based analysis of these loci can complement the techniques which are currently used for the detection and typing of these and other eubacteria.

A study was conducted to 1) determine differences in the inflammatory response following bacterial challenge between normal mares and mares with chronic endometritis and 2) to determine if enzyme activity in uterine fluid can be used to evaluate degree of inflammation in the equine uterus. Six normal mares (Group 1) and four mares with chronic endometritis (Group 2) received an intrauterine infusion of β-hemolytic streptococci on the second day of estrus. Neutrophil concentration as well as lysozyme and alkaline phosphatase activity were determined in uterine secretions obtained by placing tampons in the uterus of mares. All mares had a similar inflammatory response following bacterial challenge of the uterus, as indicated by a neutrophil response of the same magnitude. Neutrophil numbers, lysozyme and alkaline phosphatase concentrations were all increased 12 h postinoculation and declined rapidly to normal preinoculation values by 48 h after inoculation. In spite of the similarity of the clinical signs, neutrophil concentrations and enzyme activity, mares in group 1 demonstrated a markedly higher ability to eliminate the infection than mares in group 2. It is concluded that factors other than neutrophil numbers, lysozyme and alkaline phosphatase activity account for the inability of the mare to eliminate uterine infections.

Purpose : Treatment planning has been defined differently at various institutions to encompass tasks ranging from the initial evaluation of the patient to the delivery of the treatment as well as a more narrow view, focused primarily on isodose computation. To evaluate the impact of much of the new treatment-planning technology that has become available, it is necessary to define and develop recommended guidelines for the treatment-planning process. Methods and Materials : The 1989 Patterns of Care Study (PCS) included questionnaires to access treatment planning practices currently in use for the entire census of oncology facilities in the United States. These questionnaires were developed by a consensus committee consisting of both physicists and radiation oncologists whose charge was to formulate a description of current treatment-planning practices. The description was based on the committee's experience and knowledge of the treatment-planning process considered to be widely available and in general use, as well as a review of the literature. From the description of the treatment-planning process, a set of guidelines for treatment planning was developed for prostate as well as each of the other disease sites included in the PCS. Data from the study defined the general structure, methodology, process, and tools used by each institution involved in the Patterns of Care Survey Study. National averages for all of the variables were calculated with weighted averages, with the weights reflecting the sample design and number of patients in the different types of facilities. The data were stratified according to academic, hospital, or free-standing facility and were compared with the Consensus Guidelines for Treatment Planning of the Prostate. Discussion : Based on the consensus statement, the treatment-planning process was separated into the following categories : (a) Treatment-Planning Workup, (b) Treatment Plan Implementation, (c) Treatment Delivery, (d) Treatment Verification, and (e) Quality Assurance. The results from the survey were summarized for each category and compared with the consensus statement. Conclusions : Although there is an increasing trend toward using computed tomography (CT) information to acquire individualized patient data, volume definition and localization are often completed in the simulator without the direct use of CT information (47%). As more sophisticated beam arrangements and blocking are used, one needs to look at the full three-dimensional (3D) volume to ensure that there are no marginal misses due to blocking and beam arrangement. Improved and more widespread use of immobilization devices is also required with conformal treatments and reduced margins. The results of the survey helped to identify and establish the standard of practice for treatment planning of the prostate as well as to provide documentation for better defining a complete description of the treatment planning process. Well-documented guidelines will provide more consistent treatment of patients, which should have an impact on outcome.

In recent years, thermal poling of silica-based glasses has been shown to create permanent second-order nonlinearities (SON) of the order of 1 pm/V in bulk glass [1] and 0.2 pm/V in thermally poled optical fibre [2]. Despite the reproducibility and stability of the effect, the underlying mechanism has still not been fully elucidated.

Glass is a dominant material in fibre-optics technology. Recently, the discovery that dopants such as Ge and Ce render silica glass photosensitive has made possible the routine fabrication of important passive components such as fibre Bragg gratings. The absence of a second-order nonlinearity in glass however makes impossible the fabrication of active components such as modulators, switches, parametric frequency converters and frequency doublers. Thus, when efficient photoinduced second-harmonic generation was first discovered in fused silica fibres, wide-ranging studies ensued into the mechanism and properties of this unexpected phenomenon. Nonetheless, until fairly recently second harmonic generation in specially treated glasses and glass fibres has been of more scientific than practical interest, owing to levels of nonlinearity that were typically 3-4 orders of magnitude less than in the best nonlinear crystals1-3.

A survey of the gamma radiation background from terrestrial sources was conducted at the CEBAF site, Newport News, Virginia, on November 12--16, 1990, to provide a gamma radiation baseline for the site prior to the startup of the accelerator. The concentrations and distributions of the natural radioelements in exposed soil were measured, and the results of the measurements were converted into gamma-ray exposure rates. Concurrently, samples were collected for laboratory gamma spectral analyses.

Hydro-geochemical processes must be understood if the movement of radionuclides away from a breached radioactive waste canister is to be modeled and predicted. In this respect, occurrences of uranium and thorium in hydrothermal systems are under investigation in tuff and in rhyolitic tuff that was heated to simulate the effects of introduction of radioactive waste. In these studies, high-resolution gamma spectrometry and fission-track radiography are coupled with observations of alteration mineralogy and thermal history to deduce the evidence of, or potential for movement of, U and Th in response to the thermal environment. Observations to date suggest that U was mobile in the vicinity of the heater but that localized reducing environments provided by Fe-Ti-Mn-oxide minerals concentrated U and thus attenuated its migration.

Flooding or soil waterlogging inhibits gaseous exchange between the soil and atmosphere. Flooded soils rapidly become oxygen deficient, whilst the products of plant and microbial respiration such as CO2 accumulate. Plants require metabolic and/or morphological adaptions to survive such conditions. Many of the latter are mediated by plant hormones, most notably ethylene. There is evidence of a causal relationship between the rate of ethylene biosynthesis, oxygen supply and physiological adaptions such as aerenchyma development. When maize roots are exposed to hypoxia or to exogenous ethylene, aerenchyma develops in the cortex. Jackson et al. (1982; 1985) reported enhanced ethylene production in nodal roots of maize and barley under low oxygen partial pressures (3–12.5 kPa), whilst a similar response was observed in the stems of deep water rice by Metraux and Kende (1983). This enhancement of biosynthesis is controversial, since ethylene biosynthesis requires molecular oxygen. The techniques used by Jackson and co-workers and Metraux and Kende (i.e. head space analysis of excised tissue enclosed in small incubation vials) may have resulted in artifacts, e.g. as a result of wound-ethylene production after excision. To overcome this, we employed a sensitive laser-driven photoacoustic technique (sensitivity limit: 0.041 pmol m −3) to measure ethylene production from individual roots of intact seedlings, thus minimising physical perturbations.