9 results
Contributors
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- By Keith Allan, Mira Ariel, Jay David Atlas, Johan van der Auwera, Kent Bach, Emma Borg, Berit (Brit) Brogaard, Robyn Carston, Anita Fetzer, Luna Filipović, Rachel Giora, Jeanette K. Gundel, Michael Haugh, Laurence R Horn, Kasia M. Jaszczolt, Andreas H. Jucker, Napoleon Katsos, Istvan Kecskes, Ruth Kempson, Mikhail Kissine, Caterina Mauri, Jaroslav Peregrin, François Recanati, Rob van der Sandt, Louis de Saussure, Arthur Sullivan, Marina Terkourafi, Elizabeth Closs Traugott, Tim Wharton, Henk Zeevat
- Edited by Keith Allan, Monash University, Victoria, Kasia M. Jaszczolt, University of Cambridge
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- Book:
- The Cambridge Handbook of Pragmatics
- Published online:
- 05 June 2012
- Print publication:
- 12 January 2012, pp viii-ix
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Time-resolved X-ray spectroscopy of deeply buried tracer layers as a density and temperature diagnostic for the fast ignitor
- J. A. Koch, C. A. Back, C. Brown, K. Estabrook, B. A. Hammel, S. P. Hatchett, M. H. Key, J. D. Kilkenny, O. L. Landen, R. W. Lee, J. D. Moody, A. A. Offenberger, D. Pennington, M. D. Perry, M. Tabak, V. Yanovsky, R. J. Wallace, K. B. Wharton, S. C. Wilks
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- Journal:
- Laser and Particle Beams / Volume 16 / Issue 1 / March 1998
- Published online by Cambridge University Press:
- 16 October 2009, pp. 225-232
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The fast ignitor concept for inertial confinement fusion relies on the generation of hot electrons, produced by a short-pulse ultrahigh intensity laser, which propagate through high-density plasma to deposit their energy in the compressed fuel core and heat it to ignition. In preliminary experiments designed to investigate deep heating of high-density matter, we used a 20 joule, 0.5–30 ps laser to heat solid targets, and used emission spectroscopy to measure plasma temperatures and densities achieved at large depths (2–20 microns) away from the initial target surface. The targets consisted of an Al tracer layer buried within a massive CH slab; H-like and He-like line emission was then used to diagnose plasma conditions. We observe spectra from tracer layers buried up to 20 microns deep, measure emission durations of up to 200 ps, measure plasma temperatures up to Te=650 eV, and measure electron densities above 1023 cm−3. Analysis is in progress, but the data are in reasonable agreement with heating simulations when space-charge induced inhibition is included in hot-electron transport, and this supports the conclusion that the deep heating is initiated by hot electrons.
Contributors
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- By Farook Al-Azzawi, Wita Angrianni, Sanjay Asthana, Stephan Bandelow, Kathryn J. Bryan, Cynthia M. Carlsson, Jenna C. Carroll, Gemma Casadesus, Monique M. Cherrier, Laura H. Coker, María M. Corrada, Vita Priantina Dewi, Roberta Diaz Brinton, Mark A. Espeland, Mirjam I. Geerlings, Robert B. Gibbs, Carey E. Gleason, Victor W. Henderson, Patricia E. Hogan, Eef Hogervorst, Claudia H. Kawas, Anna Khaylis, Philip Kreager, Linda Kushandy, Donald Lehmann, Jin Li, Mary E. McAsey, Pauline M. Maki, Ralph N. Martins, Scott D. Moffat, Majon Muller, Theresia Ninuk, Annlia Paganini-Hill, George Perry, Christian J. Pike, Bevin N. Powers, Tri Budi W. Rahardjo, Natalie L. Rasgon, Susan M. Resnick, Emily R. Rosario, Sabarinah, Tony Sadjimim, Barbara B. Sherwin, Sally A. Shumaker, Mark A. Smith, Robert G. Struble, Chris Talbot, Wulf H. Utian, Giuseppe Verdile, Robert B. Wallace, Whitney Wharton, Katherine E. Williams, Oliver T. Wolf, Tonita E. Wroolie, Amina Yesufu, Yudarini, Liqin Zhao
- Edited by Eef Hogervorst, Loughborough University, Victor W. Henderson, Stanford University, California, Robert B. Gibbs, University of Pittsburgh, Roberta Diaz Brinton, University of Southern California
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- Book:
- Hormones, Cognition and Dementia
- Published online:
- 06 July 2010
- Print publication:
- 24 September 2009, pp vii-x
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Two new species of Digonogastra Viereck (Hymenoptera: Braconidae) parasitic on Neotropical pyralid borers (Lepidoptera) in maize, sorghum and surgane
- R. A. Wharton, J. W. Smith, Jr., D. L. J. Quicke, H. W. Browning
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- Journal:
- Bulletin of Entomological Research / Volume 79 / Issue 3 / September 1989
- Published online by Cambridge University Press:
- 10 July 2009, pp. 401-410
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Digonogastra kimballi sp. n. and D. solitaria Wharton & Quicke sp. n. are described from Texas and Mexico. They attack stalk-boring pyralids in a variety of gramineous plants, including maize, sorghum and sugarcane. Known hosts are Eoreuma loftini (Dyar) and five species of Diatraea.
The Susceptibility of various Species of Mosquitos to DDT, Dieldrin and BHC
- R. H. Wharton
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- Journal:
- Bulletin of Entomological Research / Volume 46 / Issue 2 / August 1955
- Published online by Cambridge University Press:
- 10 July 2009, pp. 301-309
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The susceptibility of various mosquitos to DDT, dieldrin and BHC has been studied. Adult females were exposed in small tubes lined with filter papers impregnated with insecticide-oil solutions. Larvae were exposed to insecticideacetone suspensions in water.
Adult mosquitos tested in London showed no striking differences in susceptibility to DDT, though the median lethal concentration (MLC) of Culex pipiens molestus Forsk. (1·6 per cent.) was greater than the MLC of Aëdes aegypti (L.) (0·9), Anopheles maculipennis var. atroparvusvan Thiel (1·0), or A. quadrimaculatus Say (·7). C. p. molestus and Aë. aegypti showed the same order of susceptibility to dieldrin and BHC, with Anopheles m. atroparvus more susceptible to both insecticides.
Trials of residual Insecticides in Window-trap Huts against Malayan Mosquitos*
- J. A. Reid, R. H. Wharton
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- Journal:
- Bulletin of Entomological Research / Volume 47 / Issue 3 / October 1956
- Published online by Cambridge University Press:
- 10 July 2009, pp. 433-468
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Trials are described with window-trap huts to test residual insecticides against vector mosquitos in Malaya. DDT, BHC and dieldrin were tested as wettable powders against Anopheles maculatus Theo., A. sundaicus (Ednw.) and Culex pipiens fatigans Wied. Some results were also obtained with Anopheles barbirostris Wulp, A. letifer Sandosham and A. umbrosus (Theo.), with species of Culex other than C. p. fatigans, with species of Mansonia, and with Aëdes albopictus (Skuse) and Aë. butleri Theo. All these mosquitos, except C. p. fatigans, are essentially outdoor species which enter houses only to bite, and which feed freely on animals as well as on man.
The validity of the window-trap hut method is discussed. It is concluded that although some mosquitos escape through the entrance louvres, and a treated hut is not quite the same as a treated and occupied room, the kills recorded are a good guide to the kills that may be expected in treated houses.
It is shown that there is usually some reduction, seldom sufficient to be important, in the number of mosquitos entering the huts in the first few weeks after treatment. This is probably due to air-borne particles of insecticide drifting through the louvres and acting on mosquitos waiting to enter.
The effect of treatment on the biting and resting behaviour of the mosquitos varied widely, being due to a combination of the properties of the particular insecticide and the habits and susceptibilities of the different species. Broadly speaking, all three insecticides tended to reduce the proportion of mosquitos obtaining a blood-meal, and the proportion remaining in the hut in the morning. But these tendencies might be modified or quite obscured by particular characteristics of the mosquito species or of the insecticide. Thus, for example, the percentage of A. maculatus obtaining a blood-meal was only reduced by 11 per cent, in the first month after treatment with DDT, compared with a 60 per cent, reduction in C. p. fatigans. It is suggested that perhaps A. maculatus did not touch the treated walls before biting and C. p. fatigans did. This difference applies to other species of Anopheles and Culex, and the average reductions in biting rate for the two genera were 19 and 62 per cent.
As another example, before treatment rather more than half of the C. p. fatigans, an indoor-resting species, remained in the hut; after treatment with DDT, which does not easily kill C. p. fatigans, over 80 per cent, were found in the window trap. By contrast, in the outdoor-resting species, A. maculatus, which is easily killed by DDT, over 90 per cent, were in the window trap before treatment, and fewer after treatment. The effect of DDT (and BHC) was to kill some of the A. maculatus before they could leave the hut, thereby reducing the proportion reaching the window trap to about 70 per cent. There was no reduction in the percentage of A. maculatus reaching the window trap with the slow-acting dieldrin.
Judged chiefly by the effect upon C. p. fatigans, DDT influenced mosquito behaviour mainly by its irritant effect, which persisted after the insecticide was no longer killing. The effect of BHC upon behaviour was due to a combination of irritance and rapid lethal action, but this did not last as long as the effect of DDT. Dieldrin has no irritant effect and it influenced behaviour only by lethal action for a short time while it was fresh; it continued to kill after it was no longer doing so rapidly enough to affect behaviour.
The most important finding was the wide range of susceptibility to the insecticides among the ten species or groups of species tested, and the fact that only two (Anopheles maculatus and A. umbrosus) seemed susceptible enough to be effectively controlled in practice by the fairly heavy doses used (200 mg. DDT, 40 mg. γ BHC or 40 mg. dieldrin) per sq. ft. With A. maculatus (and probably A. umbrosus) the 24-hour kill remained above 50 per cent, for about six months or more. With A. sundaicus (and probably A. barbirostris, A. letifer, Mansonia and Aë. butleri) the 24-hour kill fell below 50 per cent, in from one to four months. With C. p. fatigans (and probably Culex spp. and Aë. albopictus) the kill never reached 50 per cent, with DDT, and was only above 50 per cent, for one to two months with BHC and dieldrin.
A. maculatus was the most susceptible species to all three insecticides and C. p. fatigans the least; the latter was particularly insusceptible to DDT.
Heavier doses of dieldrin might be effective against the less susceptible species, and a dose of 100 mg. per sq. ft. has been found to remain effective for six months against Mansonia.
Except for the trial with light doses, dieldrin gave the best results against all species. When fresh it gave kills as high as or higher than those of BHC, and it remained effective longer than DDT or BHC.
Dieldrin and BHC when fresh gave complete or nearly complete kills of all species, but the rate of decline in the kills with time varied widely, and was quickest with the least susceptible species. With DDT, on the other hand, the rate of decline in the kill seemed to be roughly the same with all species, and it was the initial kill which varied. For the least susceptible group of species this was well under 50 per cent, in the first month, and was only 5 per cent, with one strain of C. p. fatigans; with the most susceptible it was between 80 and j 90 per cent.; it never reached 100 per cent.
Few mosquitos were found dead in treated huts, the great majority escaped into the window traps, especially with the slow-acting dieldrin. With A. maculatus in the first four months after treatment with DDT, only 25 per cent, of those dying in 24 hours were found dead in the hut. With BHC and dieldrin the corresponding figures were 14 and 2 per cent. The immediate kill (total found dead in the hut and window trap in the morning) was commonly less than half of the 24-hour kill. These results clearly show the importance of using window traps and holding mosquitos, if possible for 24 hours, if a reliable estimate of the effect of the insecticides is required.
Light doses (100 mg. DDT, 10 mg. γ BHC or 10 mg. dieldrin per sq. ft.) were tried against A. maculatus; DDT and BHC remained effective for three months, but dieldrin only for one month.
The performance of the insecticides at the higher doses can be characterised by saying that DDT is irritant and persistent, but not toxic enough except to the most susceptible of the species tested. BHC is irritant when fresh, though it kills at the same time; it is very toxic to all species, but does not remain effective long enough except against the most susceptible ones. Dieldrin is slower acting than DDT and BHC, but is non-irritant, very toxic, and remains effective longer; against less susceptible species higher doses than 40 mg. per sq. ft. will be needed. In countries where vector species rest indoors by day, dieldrin may prove particularly lasting because mosquitos will rest on treated surfaces for long periods.
The probable relation is discussed between the kills recorded in our windowtrap huts, and the degree of malaria control that may be expected when houses are sprayed. The kill necessary to control malaria depends to a large extent on how much contact the vector has with the insecticide. If its habits bring it into frequent contact with treated surfaces, a comparatively low kill on each occasion of contact may greatly reduce the population of the vector and suffice to control malaria. But if contact is infrequent, as may be expected with species of Anopheles such as those studied, which rest outdoors and feed only to a limited extent on man, then a high kill on each occasion of entry into treated houses is needed to control malaria, and there may be very little effect on the population of the vector. In these circumstances a 24-hour kill of 50 per cent., which is here considered the lower limit of effectiveness, seems a reasonable figure to adopt.
The mosquito factors which affect the degree of control achieved with residual insecticides can be thought of under three headings: (a) susceptibility to the insecticide, which largely determines the kill on each occasion of contact, and which we have shown may vary widely with different species, and is often quite low; (b) frequency of contact, which depends on habits, as these determine frequency of entry into treated shelters; (c) duration of contact on each occasion of entry, which is important when the insecticide deposit is no longer fresh, and depends mainly on whether the mosquito rests indoors by day and whether it is irritated by the insecticide.
The Behaviour and Mortality of Anopheles maculatus and Culex fatigans in experimental Huts treated with DDT and BHC*
- R. H. Wharton
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- Journal:
- Bulletin of Entomological Research / Volume 42 / Issue 1 / September 1951
- Published online by Cambridge University Press:
- 10 July 2009, pp. 1-20
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Experimental huts fitted with window traps, of the same basic design as those described by Thomson (1948), modified for Malayan conditions, were used in studying the behaviour and mortality of A. maculatus in relation to DDT and BHC. Other species of Anophelines formed a large proportion of the human bait trap catch but rarely entered the huts.
In untreated huts, A. maculatus fed at all hours of the night with a peak between 9 p.m. and midnight. The large majority left before 8 a.m. in search of outdoor resting places, at least 50 per cent. before dawn. It appeared that attraction to light was the strongest, but not the only factor influencing exit from the huts.
Large numbers of Culicines (mostly Culex fatigans) were recovered. In untreated huts about 80 per cent. were blood fed ; 28 per cent. were in the window traps.
DDT (33 per cent.) and BHC (“ Gammexane P530 and P520 ”) water dispersible powders were tested.
An application of 100 mg. DDT and 20 mg. γ BHC (P530) per sq. ft. was unsuccessful, due in part to the small numbers of mosquitos recovered. No conclusions are drawn from the results.
DDT at 200 mg. and BHC (P520) at 40 mg. γ isomer per sq. ft. were both effective for at least 12 to 16 weeks against A. maculatus. With DDT, 63 per cent. initial, and 83 per cent. 24-hour corrected mortalities were recorded over 16 weeks. With BHC, though the initial mortality dropped from 100 per cent. in weeks 1–4 to 19 per cent. in weeks 12–16, the 24-hour mortality, almost 100 per cent. for weeks 1–10, was still 88 per cent. for weeks 12–16.
DDT apparently had little effect on the feeding of A. maculatus ; with BHC there was a reduction in the percentage fed.
DDT was relatively non-lethal to C. fatigans, but had a marked irritant effect driving them into the light trap and the biting rate was reduce to 45 per cent. BHC killed all C. fatigans which entered for 2 weeks but most of its toxic effects were lost by the eighth week. The biting rate was reduced to 27 per cent. for weeks 1 to 8 and the majority of mosquitos were recovered in the light trap.
Ants, cockroaches, spiders, etc., were found to affect the number of mosquitos recovered and special precautions had to be taken against losses.
The results suggested that BHC when freshly applied acts as a repellent to mosquitos.
Mansonia uniformis was shown to be susceptible to both DDT and BHC residual deposits.
Anomalous Results from an Experimental Infection of Man with Brugia malayi (Brug, 1927)
- J. J. C. Buckley, R. H. Wharton
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- Journal:
- Journal of Helminthology / Volume 35 / Issue S1 / April 1961
- Published online by Cambridge University Press:
- 05 June 2009, pp. 17-24
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A volunteer who had been previously exposed to infection with filarial infections from naturally infected animals, i.e., Brugia malayi from Macaca irus and B. pahangi from a domestic cat, was exposed to infection with B. malayi from man. He developed signs and symptoms of tropical pulmonary eosinophilia and transitory swellings of the lower limbs, possibly of filarial origin. Up to the time of treatment with Banocide no microfilariae were found in his blood.
Persistent Isolation of an Unusual Pseudomonas Species From a Phenolic Disinfectant System
- Kathryn A. Newman, James H. Tenney, Harry A. Oken, Marcia R. Moody, Raynor Wharton, Stephen C. Schimpff
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- Journal:
- Infection Control / Volume 5 / Issue 5 / May 1984
- Published online by Cambridge University Press:
- 02 January 2015, pp. 219-222
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- May 1984
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A well-characterized unusual Pseudomonas species contaminated the piped disinfectant system of a newly-opened laminar air flow intensive care facility. This organism was frequently isolated (104-106 cfu/ml) from phenolic diluted 1:256 in the system, and could also be recovered (0.01-0.2 cfu/ml) from undiluted phenolic. During the 20-month period when this unusual Pseudomonas was present, none of the severely compromised, granulocytopenic oncology patients treated in the intensive care facility were either colonized or infected with this Pseudomonas sp. Eradication of the organism from the system proved difficult and was accomplished by removing a contaminated reservoir of diluted phenolic disinfectant followed by transient cleansing of the system with very high concentrations (84,000 ppm) of chlorine. This experience demonstrates that phenolics should be added to the list of disinfectants which can harbor Pseudomonas spp. in the clinical setting.