PubMed Health⌕ Search

Biomedical subjects

S McNeill

Publications and source records attributed to S McNeill.

6 recordsLinked to original sources
PubMed2001

Euseiusfinlandicus (Acari: Phytoseiidae) as a potential biocontrol agent against Tetranychus urticae (Acari: Tetranychidae): life history and feeding habits on three different types of food.

Life history and reproductive parameters of the generalist predatory mite Euseius (Amblyseius) finlandicus (Oudemans) were studied in the laboratory at 25 +/- 1 degrees C, with a 16L:8D photoperiod and 60 +/- 15% RH, to investigate its response to different food sources: an eriophyid mite Aceria sp., tulip pollen Tulipa gesnerana L., and two-spotted spider mite Tetranychus urticae Koch. Total developmental time of the immature stages was the shortest on eriophyid mites, followed by pollen, and then spider mites. Fecundity was highest on pollen (43.69 eggs; 1.63 eggs/female/day), then eriophyid mites (39.73 eggs; 1.37 eggs/female/day) and lowest on spider mites (18.16 eggs; 0.80 eggs/female/day). Intrinsic rate of increase (Rm), net reproductive rate (Ro) and finite rate of increase (lambda) followed the same pattern [pollen (0.168, 27.96 and 1.183, respectively), eriophyid mites (0.153, 20.81 and 1.167), spider mites (0.110, 9.44 and 1.119)]. Mean generation time (days) was the shortest on pollen (19.90), followed by eriophyid mites (20.02), and then spider mites (20.59). Average spider mite larvae consumed by E. finlandicus during immature stages were 9.18 for males and 11.85 for females. Adult E. finlandicus females consumed an average of 166.38 spider mite protonymphs during adult stage compared to an average of 66.55 by males. The number of prey protonymphs consumed per day by females was highest in the oviposition period, lower in the pre-oviposition period and the lowest in the post-oviposition period. The eriophyid mite as a prey recorded the shortest developmental time, while pollen as food recorded the highest oviposition rate in E. finlandicus. The potential of this predator as a biocontrol agent against T. urticae is discussed.

Animals↗
PubMed1996

Evidence that plant varieties respond differently to NO2 pollution as indicated by resistance to insect herbivores.

The effects of NO(2) pollution on the performance of aphids feeding on different bean varieties were investigated by fumigation experiments. The susceptibility of the different genotypes dramatically changed as the concentration of atmospheric pollutant was increased. The direction of change was not constant between varieties. Our data suggest that resistance or susceptibility of a plant variety to insect herbivory can be significantly altered when subjected to pollutant stress, thus indicating that it may be difficult to predict the susceptibility of host plants in a polluted atmosphere.

Journal Article↗
PubMed1992

Understanding the Medicare Fee Schedule and its impact on physicians under the final rule.

On January 1, 1992, the Medicare program unveiled a new method for paying physicians known as the Medicare Fee Schedule (MFS). The new fee schedule is a complex system of administrative pricing based on the resource inputs used in producing physician services. The MFS consists of three parts: 1) a Relative Value Scale, which assigns to each medical service a value relative to all other services; 2) a conversion factor, which converts the relative values into dollars; and 3) a geographic adjustment factor, which adjusts payments based on geographic differences in the cost of producing physician services. In this article, the following are addressed: how the relative values were determined; how the geographic adjustment factor was constructed; and how the conversion factor was calculated. In addition, balance billing limits and the Medicare Volume Performance Standards (MVPS) are described. Computer simulations of the impact of the MFS on payments to physicians are presented. The authors found that the MFS will 1) redistribute payments away from surgeons, radiologists, and other procedure-based specialties toward the primary care specialties; 2) redistribute payments away from urban areas toward rural areas; and 3) redistribute payments away from invasive procedures and diagnostic tests toward evaluation and management services. The authors conclude with a discussion of the future refinements of the MFS, its applicability to other payers, and whether it will accomplish its intended purposes.

Economics, Medical↗
PubMed1991

Air pollution and agricultural aphid pests. II chamber filtration experiments.

The responses of four major aphid pest species feeding on three major crops were studied in a series of experimental chambers on the roof of Imperial College in South Kensington, London. The experimental chambers were continually circulated with air which had been subjected to a variety of filtration treatments. In the first series of experiments there were three chambers subject to ambient air, charcoal-filtered air, and charcoal plus 'Purafil'-filtered air; in the subsequent experiments there were four chambers, a charcoal plus 'Purafil' plus charcoal treatment being added. These treatments provided a range of concentrations and mixtures of the ambient gases present at the site. The growth rate of aphids was measured both during filtration and post-filtration, the plants being exposed from sowing for either 42 or 84 days. In all cases there were significant effects on aphid performance which seemed to be most strongly linked to absolute and relative NO concentrations. The pattern of responses by the aphids accorded extremely well with those observed in closed-chamber fumigation experiments with stimulation of performance in relatively polluted air in all cases except Acyrthosiphon pisum (Harris) feeding on Vicia faba L. where the opposite effect was recorded.

Journal Article↗
PubMedDate not supplied

Botulinum toxin A compared with stretching casts in the treatment of spastic equinus: a randomised prospective trial.

Conservative therapies for equinus in cerebral palsy may help to postpone calf surgery in younger children. This study reports a prospective randomised trial of intramuscular botulinum toxin A (BtA) as an alternative to serial casting in 20 children with a dynamic component to calf equinus. Outcome was assessed in the short term to show the effect of one treatment cycle. Assessments were by clinical examination, video gait analysis, and three-dimensional gait analysis. BtA was of efficacy similar to that of serial casting. Tone reduction in the BtA group allowed a more prolonged improvement in passive dorsiflexion, which may allow more opportunity for increase in muscle length. Gait analysis showed an improved mean ankle kinematic pattern in a subsection of both groups, which was maintained at 12 weeks in the BtA group, whereas the cast group relapsed. There were fewer side effects in the BtA group. Median time to reintervention was similar.

Botulinum Toxins, Type A↗