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A First Mass Production Of Gas Electron Multipliers, P. S. Barbeau, J. I. Collar, J. D. Geissinger, J. Miyamoto, I. Shipsey, R. Yang Jan 2003

A First Mass Production Of Gas Electron Multipliers, P. S. Barbeau, J. I. Collar, J. D. Geissinger, J. Miyamoto, I. Shipsey, R. Yang

Department of Physics and Astronomy Faculty Publications

We report on the manufacture of a first batch of approximately 2000 Gas Electron Multipliers (GEMs) using 3M's fully automated roll-to-roll flexible circuit production line. This process allows low-cost, reproducible fabrication of a high volume of GEMs of dimensions up to 30 x 30 cm(2). First tests indicate that the resulting GEMs have optimal properties as radiation detectors. Production techniques and preliminary measurements of GEM performance are described. This now demonstrated industrial capability should help further establish the prominence of micropattern gas detectors in accelerator-based and non-accelerator particle physics, imaging and photodetection. (C) 2003 Elsevier B.V. All rights reserved.

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An Aging Study Of A Micromegas With Gem Preamplification, S. Kane, J. May, J. Miyamoto, I. Shipsey Jan 2003

An Aging Study Of A Micromegas With Gem Preamplification, S. Kane, J. May, J. Miyamoto, I. Shipsey

Department of Physics and Astronomy Faculty Publications

We have conducted the first study of the aging behavior of a MICROMEGAS detector with gas electron multiplier (GEM) preamplification. Because a MICROMEGAS is constructed with minimal insulation and because the electric field is parallel to the amplification gap, superior radiation hardness was previously reported in an Ar-Isobutane gas mixture in a stand-alone device. The MICROMEGAS is expected to tolerate an even larger accumulated charge in a cleaner gas mixture, such as Ar-CO2. However, using a MICROMEGAS as a stand-alone device in this mixture could increase discharge probability and lead to faster degradation in detector performance. We show that this …

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Evaluation Of Zno(Ga) Coatings As Alpha Particle Transducers Within A Neutron Generator, J. C. Cooper, D. S. Koltick, J. T. Mihalczo, J. S. Neal Jan 2003

Evaluation Of Zno(Ga) Coatings As Alpha Particle Transducers Within A Neutron Generator, J. C. Cooper, D. S. Koltick, J. T. Mihalczo, J. S. Neal

Department of Physics and Astronomy Faculty Publications

Neutrons generated by the deuterium-tritium reaction (D-2 + T-3 --> n + alpha) are correlated to the alpha particle by energy and momentum conservation to lie along trajectories 180degrees with respect to one another. An associated particle neutron generator uses this spatial correlation to infer the neutron trajectory by detecting the alpha particle. This technique can be used to suppress backgrounds and in building three-dimensional images using the return excitation gamma-ray energy due to the neutron interactions. The critical-performance component of the system is the alpha detection element, which is embedded within the neutron generator accelerator head. This element must …

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A Study Of A Micromegas Detector With A New Readout Scheme, S. Kane, J. May, J. Miyamoto, I. Shipsey Jan 2003

A Study Of A Micromegas Detector With A New Readout Scheme, S. Kane, J. May, J. Miyamoto, I. Shipsey

Department of Physics and Astronomy Faculty Publications

A new MICROMEGAS detector readout scheme that protects the readout electronics from damage caused by discharge initiated by large gas amplification has been studied. In the new method, the signal is produced by a readout plane placed below the MICROMEGAS detector anodes. The ratio of the signal amplitude on the readout plane was more than 65% of the signal amplitude on the cathode of the MICROMEGAS. (C) 2003 Elsevier Science B.V. All rights reserved.

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Status Of The Cleo Iii Silicon Tracker, E. Von Toerne, M. S. Alam, J. P. Alexander, A. Anastassov, K. Arndte, A. Bean, F. Blanc, G. Boyd, G. W. Brandenburg, J. W. Cherwinka, J. E. Duboscq, E. Eckhart, A. Ershov, J. Fast, A. D. Foland, P. I. Hopman, K. K. Gan, Y. Gao, H. P. Kagan, S. Kane, L. Kazkaz, R. Kass, D. Kim, J. Lee, A. J. Magerkurth, D. Miller, J. Miyamoto, M. Neustadt, J. Oliver, V. Pavlunin, C. Rush, T. Selby, H. Severini, M. Shepherd, I. Shipsey, P. Skubic, T. Smith, P. Sterner, S. Timm, D. Tournear, C. W. Ward, M. Weinberger, Q. Zhang, X. Zhao, M. M. Zoeller Jan 2003

Status Of The Cleo Iii Silicon Tracker, E. Von Toerne, M. S. Alam, J. P. Alexander, A. Anastassov, K. Arndte, A. Bean, F. Blanc, G. Boyd, G. W. Brandenburg, J. W. Cherwinka, J. E. Duboscq, E. Eckhart, A. Ershov, J. Fast, A. D. Foland, P. I. Hopman, K. K. Gan, Y. Gao, H. P. Kagan, S. Kane, L. Kazkaz, R. Kass, D. Kim, J. Lee, A. J. Magerkurth, D. Miller, J. Miyamoto, M. Neustadt, J. Oliver, V. Pavlunin, C. Rush, T. Selby, H. Severini, M. Shepherd, I. Shipsey, P. Skubic, T. Smith, P. Sterner, S. Timm, D. Tournear, C. W. Ward, M. Weinberger, Q. Zhang, X. Zhao, M. M. Zoeller

Department of Physics and Astronomy Faculty Publications

The CLEO-III silicon vertex detector is a 4-layer device with double-sided silicon sensors arranged in a barrel design, covering 93% of the solid angle. After initially meeting its design goals of signal-to-noise performance and spatial resolution, the signal efficiency deteriorated on the rphi sensor side in the two innermost layers due to radiation induced sensor effects. Operation of the two outermost layers and the z-coordinate readout in all layers is stable. (C) 2003 Published by Elsevier Science B.V.

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High-Speed Depth-Sectioned Wide-Field Imaging Using Low-Coherence Photorefractive Holographic Microscopy, C. Dunsby, Y. Gu, Z. Ansari, P. M. W. French, L. Peng, P. Yu, M. R. Melloch, D. D. Nolte Jan 2003

High-Speed Depth-Sectioned Wide-Field Imaging Using Low-Coherence Photorefractive Holographic Microscopy, C. Dunsby, Y. Gu, Z. Ansari, P. M. W. French, L. Peng, P. Yu, M. R. Melloch, D. D. Nolte

Department of Physics and Astronomy Faculty Publications

Low-coherence photorefractive holography has the potential to acquire wide-field coherence-gated images at frame rates approaching 1000 frames/s, including through scattering media. We present a quantitative analysis of the system optimization and limits of performance for coherence-gated imaging through scattering media using photorefractive holography and compare this performance to direct CCD detection. We show that, for high optical quality recording photorefractive multiple quantum well devices, photorefractive holography has the potential to provide a higher dynamic range than is possible with direct CCD-based detection. (C) 2003 Elsevier Science B.V. All rights reserved.

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Accelerator Search For Cosmic Simps, V. Teplitz, D. Javorsek, E. Fischbach, R. Mohapatra Jan 2003

Accelerator Search For Cosmic Simps, V. Teplitz, D. Javorsek, E. Fischbach, R. Mohapatra

Department of Physics and Astronomy Faculty Publications

We give limits on the contribution to the cosmic dark matter density of neutral, stable, strongly interacting massive particles (SIMPs). The limits axe inferred from an accelerator mass spectrometry (AMS) experiment at the Purdue Rare Isotope Measurement Laboratory (PRIME Lab). The experiment accelerated nuclei of both gold and iron. The "SIMP signal" would be discovery of nuclei of these elements with anomalous masses. Since no such signal was observed for SIMP masses up to over 1 TeV, cosmic SIMP density limits may be given. Determining the minimum time of exposure to SIMPs trapped in the galaxy is a crucial element …

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Structure And Diffusion Time Scales Of Disordered Clusters, E. Cuansing, H. Nakanishi Jan 2003

Structure And Diffusion Time Scales Of Disordered Clusters, E. Cuansing, H. Nakanishi

Department of Physics and Astronomy Faculty Publications

The eigenvalue spectra of the transition probability matrix for random walks traversing critically disordered clusters in three different types of percolation problems show that the random walker sees a developing Euclidean signature for short time scales as the local, full-coordination constraint is iteratively applied. (C) 2002 Elsevier Science B.V. All rights reserved.

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Ams Dating Of Early Shellmounds Of The Southeastern Brazilian Coast, T. A. Lima, K. D. Macario, R. M. Anjos, P. R. S. Gomes, M. M. Coimbra, D. Elmore Jan 2003

Ams Dating Of Early Shellmounds Of The Southeastern Brazilian Coast, T. A. Lima, K. D. Macario, R. M. Anjos, P. R. S. Gomes, M. M. Coimbra, D. Elmore

Department of Physics and Astronomy Faculty Publications

This paper discusses the chronology of prehistoric settlements of the central-south Brazilian coast. A charcoal sample from a coastal shellmound of Rio de Janeiro State was dated by C-14-AMS to 7,860+/-80 years BP as part of an interdisciplinary project between physicists and archaeologists. This is an unexpected result that reinforces two similar previous early dates for the same region, which were questioned by Brazilian archaeologists because they implied in putting back by some two thousand years the antiquity consensually accepted for the settlement of that region.

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Composition Of The First Bulk Melt Sample From A Volcanic Region Of Mars: Queen Alexandra Range 94201, D. A. Kring, J. D. Gleason, T. D. Swindle, K. Nishiizumi, M. W. Caffee, D. H. Hill, A. J. T. Jull, W. V. Boynton Jan 2003

Composition Of The First Bulk Melt Sample From A Volcanic Region Of Mars: Queen Alexandra Range 94201, D. A. Kring, J. D. Gleason, T. D. Swindle, K. Nishiizumi, M. W. Caffee, D. H. Hill, A. J. T. Jull, W. V. Boynton

Department of Physics and Astronomy Faculty Publications

Antarctic meteorite Queen Alexandra Range (QUE) 94201 is a 12 g basaltic achondrite dominated by plagioclase (now maskelynite) and zoned low- and high-Ca pyroxene. Petrologic, geochemical, and isotopic analyses indicate that it is related to previously described basaltic and lherzolitic shergottites, which are a group of igneous meteorites that are believed to be from Mars. Unlike previous shergottites, however, QUE 94201 represents a bulk melt rather than a cumulate fraction, meaning it can be used to infer magmatic source regions and the compositions of other melts on Mars. This melt has much more Fe and P than basaltic melts produced …

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Ultrasound Detection Through Turbid Media, P. Yu, L. Peng, D. D. Nolte, M. R. Melloch Jan 2003

Ultrasound Detection Through Turbid Media, P. Yu, L. Peng, D. D. Nolte, M. R. Melloch

Department of Physics and Astronomy Faculty Publications

Optical coherence-domain reflectometry and laser-based ultrasound detection have been combined with the use of adaptive optics to detect ultrasound through turbid media. The dynamic hologram in a photorefractive quantum-well device performs as a coherence gate that eliminates multiply scattered background. Quadrature homodyne detection conditions are selected by the choice of center wavelength of the pulse spectrum, requiring no active stabilization or feedback. A depth resolution of 30 mum was achieved, with a pulse duration of nominally 120 fs for ultrasound detection through turbid media up to optical thicknesses of 11 mean free scattering lengths. (C) 2003 Optical Society of America.

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Chandra Observations Of The Guitar Nebula, D. S. Wong, J. M. Cordes, S. Chatterjee, E. G. Zweibel, J. P. Finley, R. W. Romani, M. P. Ulmer Jan 2003

Chandra Observations Of The Guitar Nebula, D. S. Wong, J. M. Cordes, S. Chatterjee, E. G. Zweibel, J. P. Finley, R. W. Romani, M. P. Ulmer

Department of Physics and Astronomy Faculty Publications

As part of a multi-wavelength study, we report on a 50 ks Chandra/ACIS observation of the Guitar Nebula, a bow shock nebula associated with the radio pulsar B2224+65. We see a "hot spot" at the tip of the bow shock. We also notice a "jet" of X-ray emission at position angle (PA) -69degrees. However, the proper motion of the pulsar and the axis of optical emission is at PA 52.degrees1. We discuss the resulting interpretations of the relativistic pulsar wind and the surrounding ISM.

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Illegality And Public Policy, Boon Leong, Andrew Phang Jan 2003

Illegality And Public Policy, Boon Leong, Andrew Phang

Research Collection Yong Pung How School Of Law

No abstract provided.

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The Law Of Guarantees In Singapore & Malaysia, Kee Yang Low Jan 2003

The Law Of Guarantees In Singapore & Malaysia, Kee Yang Low

Research Collection Yong Pung How School Of Law

No abstract provided.

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Pisa 2003 Australia Student, Achievement And School Data [Sas] [Data Set], Sue Thomson, Lisa De Bortoli, John Cresswell Jan 2003

Pisa 2003 Australia Student, Achievement And School Data [Sas] [Data Set], Sue Thomson, Lisa De Bortoli, John Cresswell

OECD Programme for International Student Assessment (PISA) Australia

No abstract provided.

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Maintain Hydraulic Control Using Deep Rooted Tree Systems, A. Ferro, M. Gefell, Roger Kjelgren, D. S. Lipson, N. Zollinger, S. Jackson Jan 2003

Maintain Hydraulic Control Using Deep Rooted Tree Systems, A. Ferro, M. Gefell, Roger Kjelgren, D. S. Lipson, N. Zollinger, S. Jackson

Plants, Soils, and Climate Faculty Publications

Groundwater phytotechnology systems are currently being used to control the migration of contaminant plumes and remove groundwater that flows into containment areas. Trees in such systems function by reducing recharge and using groundwater via transpiration. A stand of deep-rooted trees can act as a biological "pump", removing a substantial amount of water from the saturated zone. Depth to groundwater compared to rooting depth is an important consideration Many useful tree species are not naturally deep-rooted, but various cultural practices can produce trees with roots that are deep enough to tap into the water table. Hydraulic control can be calculated or …

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Integrated Arthropod Pest Management Systems For Human Health Improvement In Africa, Johann Baumgärtner, Fritz Schulthess, Yunlong Xia Jan 2003

Integrated Arthropod Pest Management Systems For Human Health Improvement In Africa, Johann Baumgärtner, Fritz Schulthess, Yunlong Xia

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In a sub-Saharan African context, limited natural resources, infectious diseases, including those transmitted by arthropod vectors, and chronic exposure to food contaminated with mycotoxin-producing fungi which, among others, are vectored by insects, are among the major constraints to human health. Thus, pest control should be an important component in human health improvement projects. It appears that the advantages of preventive over curative methods are rarely recognised in Africa, with more emphasis being given to the search for the 'silver bullet' than to integrated control approaches. Integrated pest management (IPM) systems can be assigned to different decision-making levels as well as …

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Ring A-Seco Mosquito Larvicidal Limonoids From Turraea Wakefieldii, Mary Ndung'u, Ahmed Hassanali, Antony M. Hooper, Sumesh Chhabra, Thomas A. Miller, Rowena L. Paul, Baldwyn Torto Jan 2003

Ring A-Seco Mosquito Larvicidal Limonoids From Turraea Wakefieldii, Mary Ndung'u, Ahmed Hassanali, Antony M. Hooper, Sumesh Chhabra, Thomas A. Miller, Rowena L. Paul, Baldwyn Torto

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Five novel limonoids, 1-5, were isolated from the root bark of Turraea wakefieldii and were characterized as tecleaninoid derivatives. This is the first report of the natural occurrence of tecleanin-type limonoids with a five-membered-ring A-seco structure for which we propose the name neotecleanins. The relative stereochemical structures of compounds 1-5 were established on the basis of NMR spectroscopy. The absolute stereochemical structure of 5 was confirmed by X-ray diffraction methods. In mosquito larvicidal assays, compounds 1, 2 and 4 showed dose-dependent larvicidal activity against larvae of Anopheles gambiae s.s. © 2003 Elsevier Ltd. All rights reserved.

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Desert Reading, Desert Listening (Audio), Joel B. Green Jan 2003

Desert Reading, Desert Listening (Audio), Joel B. Green

ATS Chapel Services

No abstract provided.

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Effects Of Different Neem Formulations On The Twospotted Spider Mite, Tetranychus Urticae Koch, On Tomato (Lycopersicon Esculentum Mill.), Markus Knapp, Sophia Shaban Kashenge Jan 2003

Effects Of Different Neem Formulations On The Twospotted Spider Mite, Tetranychus Urticae Koch, On Tomato (Lycopersicon Esculentum Mill.), Markus Knapp, Sophia Shaban Kashenge

All Peer-Reviewed Publications

The effects of four different neem formulations (Neemros®, Neemroc EC®, Neemroc Combi and Saroneem) and a combination of Neemros® with a synthetic acaricide (Mitac®) on the twospotted spider mite (Tetranychus urticae Koch) were compared with Mitac® on tomato (Lycopersicon esculentum Mill.) leaf discs in the laboratory. The following LC50 were determined: Neemroc EC® 12.9 ml/l, Saroneem 5.8 ml/l, Neemroc Combi 1.0 ml/l and Mitac® + Neemros® 1 ml/l + 17.6 g/l. No LC50 was determined for Neemros® since the highest mortality observed was 11.4%. The combination of Mitac® and Neemros® resulted in the highest mortality after 24 hours (83.3%), followed …

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Screening Tomato (Lycopersicon Esculentum Mill.) Accessions For Resistance To The Twospotted Spider Mite Tetranychus Urticae Koch: Population Growth Studies, Markus Knapp, Debora Apiyo Mugada, Stephen Gaya Agong Jan 2003

Screening Tomato (Lycopersicon Esculentum Mill.) Accessions For Resistance To The Twospotted Spider Mite Tetranychus Urticae Koch: Population Growth Studies, Markus Knapp, Debora Apiyo Mugada, Stephen Gaya Agong

All Peer-Reviewed Publications

The resistance of 63 tomato (Lycopersicon esculentum Mill.) accessions to the twospotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae), was investigated in screen house experiments and compared to Money Maker, a T. urticae-susceptible variety widely grown in Kenya. The number of motile mite stages 12 days after inoculation with 5 adult female mites was significantly lower than in the control variety (Money Maker) in seven accessions (Marglobe, Roma-VF, 94 RT 330, Continental Michel, Early Pearson, ARP 366-4 and 94 RT 316). Egg numbers were significantly lower than in the control in 14 accessions (Marglobe, Cal-J-VF, Roma-VF, Beauty, 95 RT 315, …

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Evidence For The Involvement Of A Tsetse Midgut Lectin-Trypsin Complex In Differentiation Of Bloodstream-Form Trypanosomes, L. U. Abubakar, G. Zimba, C. Wells, F. Mulaa, E. O. Osir Jan 2003

Evidence For The Involvement Of A Tsetse Midgut Lectin-Trypsin Complex In Differentiation Of Bloodstream-Form Trypanosomes, L. U. Abubakar, G. Zimba, C. Wells, F. Mulaa, E. O. Osir

All Peer-Reviewed Publications

We have previously described a bloodmeal-induced molecule (lectin-trypsin complex) from the midgut of the tsetse fly, Glossina longipennis, with both lectin and trypsin activities (Osir et al., 1995). In this paper, we report on the isolation of a similar molecule from the midguts of Glossina fuscipes fuscipes and provide direct evidence for its involvement in the development of African trypanosomes. The molecule (native Mr ∼65,700) has two non-covalently linked subunits, Mr ∼28,800 and Mr ∼35,700. The native molecule was found to be capable of inducing differentiation of bloodstream-form trypanosomes into procyclic (midgut forms) in vitro. In the assays, specific antibodies …

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High Seasonal Variation In Entomologic Inoculation Rates In Eritrea, A Semi-Arid Region Of Unstable Malaria In Africa, Josephat Shililu, Tewolde Ghebremeskel, Solomon Mengistu, Helen Fekadu, Mehari Zerom, Charles Mbogo, John Githure, Robert Novak, Eugene Brantly, John C. Beier Jan 2003

High Seasonal Variation In Entomologic Inoculation Rates In Eritrea, A Semi-Arid Region Of Unstable Malaria In Africa, Josephat Shililu, Tewolde Ghebremeskel, Solomon Mengistu, Helen Fekadu, Mehari Zerom, Charles Mbogo, John Githure, Robert Novak, Eugene Brantly, John C. Beier

All Peer-Reviewed Publications

Entomologic studies were conducted in eight villages to investigate the patterns of malaria transmission in different ecologic zones in Eritrea. Mosquito collections were conducted for 24 months between September 1999 and January 2002. The biting rates of Anopheles arabiensis were highly seasonal, with activity concentrated in the wet season between June and October in the highlands and western lowlands, and between December and March in the coastal region. The biting rates in the western lowlands were twice as high as in the western escarpment and 20 times higher than in the coastal region. Sporozoite rates were not significantly different among …

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Geographic Differences In Host Acceptance And Suitability Of Two Cotesia Sesamiae Populations In Zimbabwe, P. Chinwada, W. A. Overholt, C. O. Omwega, J. M. Mueke Jan 2003

Geographic Differences In Host Acceptance And Suitability Of Two Cotesia Sesamiae Populations In Zimbabwe, P. Chinwada, W. A. Overholt, C. O. Omwega, J. M. Mueke

All Peer-Reviewed Publications

Three lepidopteran stemborers, Busseola fusca Fuller (Noctuidae), Sesamia calamistis Hampson (Noctuidae), and Chilo partellus (Swinhoe) (Crambidae), were evaluated for their acceptability for oviposition and suitability for development by two populations of the larval endoparasitoid Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae) occurring in the highveld (>1200m) and lowveld (<600 m) regions of Zimbabwe. Mating studies were also conducted to determine reproductive compatibility between the populations. Both C. sesamiae populations preferred the noctuids to C. partellus for oviposition. possibly reflecting differences in evolutionary history. Although B. fusca was partially suitable for development of lowveld C. sesamiae, all three hosts were suitable for development of the highveld population. Crosses between highveld and lowveld C. sesamiae were compatible, and were generally not different from the intra-population crosses in developmental time, % adult emergence and sex ratio. However, broods were much larger when highveld males were used in the mating combinations. We conclude that although there is host overlap and probably a considerable degree of outbreeding between the two C. sesamiae populations, there are still significant genetic differences between them. Within Zimbabwe, it is unlikely that the deliberate introduction of either population outside its region of occurrence will give meaningful stemborer control. © 2003 Elsevier Science (USA). All rights reserved.

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Olfactory Responses Of Cotesia Flavipes (Hymenoptera: Braconidae) To Target And Non-Target Lepidoptera And Their Host Plants, Bekele Jembere, Adele J. Ngi-Song, W. Overholt Jan 2003

Olfactory Responses Of Cotesia Flavipes (Hymenoptera: Braconidae) To Target And Non-Target Lepidoptera And Their Host Plants, Bekele Jembere, Adele J. Ngi-Song, W. Overholt

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The attraction of Cotesia flavipes Cameron to volatiles from a range of non-target lepidopteran larvae and their host plants (grasses and trees) or food substrate (honeycomb) was evaluated using a Y-tube olfactometer. The non-target host larvae used in the study included Galleria mellonella (L.), Charaxes cithaeron Felder, Bombyx mori L., and Eldana saccharina Walker. The target insects, Chilo partellus (Swinhoe) and Chilo orichalcociliellus (Strand), were used as controls. Host plants included Afzelia quanzensis Welw., Morus alba L., Cyperus papyrus L., Pennisetum purpureum Schumach, and Zea mays L. The response of C. flavipes to volatiles from the non-target larvae and their …

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Host Specificity Of Psyttalia Cosyrae (Hymenoptera: Braconidae) And The Effect Of Different Host Species On Parasitoid Fitness, Samira A. Mohamed, William A. Overholt, Robert A. Wharton, Slawomir A. Lux, Elameen M. Eltoum Jan 2003

Host Specificity Of Psyttalia Cosyrae (Hymenoptera: Braconidae) And The Effect Of Different Host Species On Parasitoid Fitness, Samira A. Mohamed, William A. Overholt, Robert A. Wharton, Slawomir A. Lux, Elameen M. Eltoum

All Peer-Reviewed Publications

Psyttalia cosyrae (Wilkinson) (Hymenoptera: Braconidae) is a synovigenic, koinobiont larval-pupal parasitoid of Ceratitis cosyra (Walker) (Diptera: Tephritidae), and possibly other tephritid fruit flies. Host acceptance and suitability of medfly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), mango fruit fly, Ceratitis cosyra, Natal fruit fly, Ceratitis rosa Karsch, Ceratitis fasciventris (Bezzi), Ceratitis anonae Graham, and melon fruit fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), for oviposition and development of this parasitoid were investigated. The effect of different host species on traits widely used to assess parasitoid fitness was also evaluated. Psyttalia cosyrae accepted all host species tested, but acceptance varied. In no choice tests, …

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Isoflavanones From The Allelopathic Aqueous Root Exudate Of Desmodium Uncinatum, Muniru K. Tsanuo, Ahmed Hassanali, Antony M. Hooper, Zeyaur Khan, Festus Kaberia, John A. Pickett, Lester J. Wadhams Jan 2003

Isoflavanones From The Allelopathic Aqueous Root Exudate Of Desmodium Uncinatum, Muniru K. Tsanuo, Ahmed Hassanali, Antony M. Hooper, Zeyaur Khan, Festus Kaberia, John A. Pickett, Lester J. Wadhams

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Three isoflavanones, 5,7,2′,4′ -tetrahydroxy-6-(3-methylbut-2-enyl)isoflavanone (1), 4″,5″ -dihydro-5,2′,4′-trihydroxy-5″-isopropenylfurano-(2″, 3″;7,6)-isoflavanone (2) and 4″,5″-dihydro-2′ -methoxy-5,4′-dihydroxy-5″-isopropenylfurano-(2″,3″;7,6) -isoflavanone (3) and a previously known isoflavone 5,7,4′ -trihydroxyisoflavone [genistein (4)] were isolated and characterised spectroscopically from the root exudate of the legume Desmodium uncinatum (Jacq.) DC. We propose the names uncinanone A, B, and C for compounds 1, 2 and 3, respectively. Isolated fractions containing uncinanone B (2) induced germination of seeds from the parasitic weed Striga hermonthica (Del.) Benth. and fractions containing uncinanone C (3) moderately inhibited radical growth, the first example of a newly identified potential allelopathic mechanism to prevent S. hermonthica parasitism. © 2003 …

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Spatial And Temporal Heterogeneity Of Anopheles Mosquitoes And Plasmodium Falciparum Transmission Along The Kenyan Coast, Charles M. Mbogo, Joseph M. Mwangangi, Joseph G. Nzovu, Weidong Gu, Guiyan Yan, James T. Gunter, Chris Swalm, Joseph Keating, James L. Regens, Josephat I. Shililu, John I. Githure, John C. Beier Jan 2003

Spatial And Temporal Heterogeneity Of Anopheles Mosquitoes And Plasmodium Falciparum Transmission Along The Kenyan Coast, Charles M. Mbogo, Joseph M. Mwangangi, Joseph G. Nzovu, Weidong Gu, Guiyan Yan, James T. Gunter, Chris Swalm, Joseph Keating, James L. Regens, Josephat I. Shililu, John I. Githure, John C. Beier

All Peer-Reviewed Publications

The seasonal dynamics and spatial distributions of Anopheles mosquitoes and Plasmodium falciparum parasites were studied for one year at 30 villages in Malindi, Kilifi, and Kwale Districts along the coast of Kenya. Anopheline mosquitoes were sampled inside houses at each site once every two months and malaria parasite prevalence in local school children was determined at the end of the entomologic survey. A total of 5,476 Anopheles gambiae s.l. and 3,461 An. funestus were collected. Species in the An. gambiae complex, identified by a polymerase chain reaction, included 81.9% An. gambiae s.s., 12.8% An. arabiensis, and 5.3% An. merus. Anopheles …

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Malariasphere: A Greenhouse-Enclosed Simulation Of A Natural Anophelesgambiae (Diptera: Culicidae) Ecosystem In Western Kenya, Bart G.J. Knols, Basilio N. Njiru, Evan M. Mathenge, Wolfgang R. Mukabana, John C. Beier, Gerry F. Killeen Dec 2002

Malariasphere: A Greenhouse-Enclosed Simulation Of A Natural Anophelesgambiae (Diptera: Culicidae) Ecosystem In Western Kenya, Bart G.J. Knols, Basilio N. Njiru, Evan M. Mathenge, Wolfgang R. Mukabana, John C. Beier, Gerry F. Killeen

All Peer-Reviewed Publications

Background: The development and implementation of innovative vector control strategies for malaria control in Africa requires in-depth ecological studies in contained semi-field environments. This particularly applies to the development and release of genetically-engineered vectors that are refractory to Plasmodium infection. Here we describe a modified greenhouse, designed to simulate a natural Anopheles gambiae Giles ecosystem, and the first successful trials to complete the life-cycle of this mosquito vector therein. Methods: We constructed a local house, planted crops and created breeding sites to simulate the natural ecosystem of this vector in a screen-walled greenhouse, exposed to ambient climate conditions, in western …

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Characterization Of Protective Antigens From The Midgut Of Amblyomma Variegatum Ticks, J. K. Kinyua, E. O. Osir, D. O. Ogoyi, E. K. Nguu Dec 2002

Characterization Of Protective Antigens From The Midgut Of Amblyomma Variegatum Ticks, J. K. Kinyua, E. O. Osir, D. O. Ogoyi, E. K. Nguu

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Separation of midgut membrane proteins from the tick, Ambylomma variegatum, using a non-ionic detergent (Triton X-114), resulted in two protein fractions, namely DET (detergent) and AQ (aqueous). In immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (Mr ∼ 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (Mr ∼ 54,000 and 67,000) were detected in the DET and AQ fractions, respectively. Three of the DET fraction proteins Mr ∼ 27,000, 67,000 and 95,000 were glycosylated since they bound to the lectin, concanavalin A. In 2-dimensional gel electrophoresis, the AQ and DET fraction proteins were found to be acidic in …

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