Attempts to Locate Culex Tarsalis Larvae In Traditional Mosquito - Breeding Habitats from Brookings County, South Dakota

A total of 33 potential mosquito breeding sites were identified and selected during the early spring of 2003. These mosquito habitats were selected from both natural and urban settings within Brookings County, Sd, and represented the various classifications of habitats potentially used by various mosquito species for larval development including: flowing streams, ponded streams, lake edges, swamps and marshes, shallow-permanent ponds, shallow-temporary pools, intermittent- ephemeral puddles, natural containers and artificial containers. These sites were monitored weekly during the summer for the condition of the water and sampled for the presence of mosquito larvae. A standard collection of 10 “dips” using a 13 cm mosquito dipper was made from each location. Collected larvae were preserved (70% ethanol), dehydrated in an ethanol series, mounted on glass slides, identified and enumerated. Focus was given to Culex larvae because Culex tarsalis is a primary vector for West Nile Virus in South Dakota. Moderate numbers of larvae were recovered from many of the sites during the summer, but by August 6 only 21 of the sites contained water, and therefore, still able to support larval development. Culex tarsalis larvae were not found in any natural site; the only sites they where they could be found were 6 artificial containers possessing these larvae only after August 5. Culex tarsalis larvae were found in 2 locations that were not part of the original study sites. These included larvae found during early summer in an artificial barrel mesocosm within Oak Lake, and larvae found in a water-filled, shallow tire-imprint located in a hayfield in Minnehaha County, South Dakota

Mosquito Populations from Eastern South Dakota During 2001 and 2002

In 2001, the South Dakota Department of Health initiated a program to monitor mosquitoes in South Dakota for the presence of the West Nile Virus. During the first year (2001), a pilot survey was conducted near Brookings, SD. To collect mosquitoes, CDC miniture light traps were used without carbondioxide baiting, beginning on July 3 and ending on August 2, 2001. Results from this small study (total of 2,042 mosquitoes during 10 collection days) showed that the most common mosquotes were Aedes vexans (88.2%), Culex tarsalis, (5.2%), and Aedes dorsalis (4.9%). An additional survey was conducted during the summer of 2002 focusing on 8 different sites (Brandon, Brookings, Huron, North Sioux City, Oak Lake Field Station, Watertown, Waubay and Yankton) in eastern South Dakota. Mosquitoes were collected with the same traps used for 2001, however, the traps were baited with carbon diaoxide (dry ice). Trapping began on June 1 and ended on September 1, 2002. A total of 18,971 mosquitoes were collected from the 8 sites during the 127 trapping days of this survey. From this population, 21 different mosquito species from 8 different genera were identified. The vast majority of mosquitoes were Aedes vexans (86.3%), but Culex tarsalis was also present in significant numbers (7.2%). Aedes vexans populations varied to a greater degree during the summer than did Culex tarsalis. The public’s perceptions of the danger of West Nile Virus transmission is probably more determined by Aedes population than by Culex populations even though Aedes likely plays little or no role in the transmission of this disease

Preliminary Solar Sail Design and Fabrication Assessment: Spinning Sail Blade, Square Sail Sheet

Blade design aspects most affecting producibility and means of measurement and control of length, scallop, fullness and straightness requirements and tolerances were extensively considered. Alternate designs of the panel seams and edge reinforcing members are believed to offer advantages of seam integrity, producibility, reliability, cost and weight. Approaches to and requirements for highly specialized metalizing methods, processes and equipment were studied and identified. Alternate methods of sail blade fabrication and related special machinery, tooling, fixtures and trade offs were examined. A preferred and recommended approach is also described. Quality control plans, inspection procedures, flow charts and special test equipment associated with the preferred manufacturing method were analyzed and are discussed

Calibration of centre-of-mass energies at LEP 2 for a precise measurement of the W boson mass

The determination of the centre-of-mass energies for all LEP 2 running is presented. Accurate knowledge of these energies is of primary importance to set the absolute energy scale for the measurement of the W boson mass. The beam energy between 80 and 104 GeV is derived from continuous measurements of the magnetic bending field by 16 NMR probes situated in a number of the LEP dipoles. The relationship between the fields measured by the probes and the beam energy is defined in the NMR model, which is calibrated against precise measurements of the average beam energy between 41 and 61 GeV made using the resonant depolarisation technique. The validity of the NMR model is verified by three independent methods: the flux-loop, which is sensitive to the bending field of all the dipoles of LEP; the spectrometer, which determines the energy through measurements of the deflection of the beam in a magnet of known integrated field; and an analysis of the variation of the synchrotron tune with the total RF voltage. To obtain the centre-of-mass energies, corrections are then applied to account for sources of bending field external to the dipoles, and variations in the local beam energy at each interaction point. The relative error on the centre-of-mass energy determination for the majority of LEP 2 running is 1.2 x 10^{-4}, which is sufficiently precise so as not to introduce a dominant uncertainty on the W mass measurement.Comment: 79 pages, 45 figures, submitted to EPJ

High Resolution Hybrid Pixel Sensors for the e+e- TESLA Linear Collider Vertex Tracker

In order to fully exploit the physics potential of a future high energy e+e- linear collider, a Vertex Tracker, providing high resolution track reconstruction, is required. Hybrid Silicon pixel sensors are an attractive option, for the sensor technology, due to their read-out speed and radiation hardness, favoured in the high rate environment of the TESLA e+e- linear collider design but have been so far limited by the achievable single point space resolution. In this paper, a conceptual design of the TESLA Vertex Tracker, based on a novel layout of hybrid pixel sensors with interleaved cells to improve their spatial resolution, is presented.Comment: 12 pages, 5 figures, to appear in the Proceedings of the Vertex99 Workshop, Texel (The Netherlands), June 199

Evaluation of the LEP Centre-of-Mass Energy Above the W-Pair Production Threshold

Knowledge of the centre-of-mass energy at LEP2 is of primary importance to set the absolute energy scale for the measurement of the W-boson mass. The beam energy above 80 GeV is derived from continuous measurements of the magnetic bending field by 16 NMR probes situated in a number of the LEP dipoles. The relationship between the fields measured by the probes and the beam energy is calibrated against precise measurements of the average beam energy between 41 and 55 GeV made using the resonant depolarisation technique. The linearity of the relationship is tested by comparing the fields measured by the probes with the total bending field measured by a flux loop. This test results in the largest contribution to the systematic uncertainty. Several further corrections are applied to derive the the centre-of-mass energies at each interaction point. In addition the centre-of-mass energy spread is evaluated. The beam energy has been determined with a precision of 25 MeV for the data taken in 1997, corresponding to a relative precision of 2.7x10^{-4}. This is small in comparison to the present uncertainty on the W mass measurement at LEP. However, the ultimate statistical precision on the W mass with the full LEP2 data sample should be around 25 MeV, and a smaller uncertainty on the beam energy is desirable. Prospects for improvements are outlined.Comment: 24 pages, 10 figures, Latex, epsfig; replaced by version accepted by European Physical Journal

Vocational knowledge in motion: rethinking vocational knowledge through vocational teachers' professional development

The paper presents empirical data to consider some of the current debates concerning the nature of vocational knowledge taught in Further Education colleges to students following craft, vocational and occupational courses. The concept of ‘knowledge in motion’ and workplace learning theories are employed as a conceptual framework to examine the continuing professional development (CPD) activities of vocational teachers. This is used to shed light on the ways in which teachers use CPD as a means of accessing and transporting vocational knowledge from occupations to classrooms. Empirical data were gathered through questionnaire, in-depth interviews and participant observation. The findings are presented around five themes: (1) the range of CPD engaged with by vocational teachers; (2) the limitations of propositional, explicit knowledge; (3) engaging with and capturing tacit knowledge; (4) managing the temporality of vocational knowledge; and (5) networking within and to the occupation. Findings suggests that vocational knowledge is distributed and networked and this conceptualisation makes visible some of the ways teachers are able, through CPD activity, to transport vocational knowledge from occupations to classrooms

Recent Results on Energy Calibration at LEP

The determination of the centre-of-mass energy at the four experiments installed on the CERN Large Electron Positron (LEP) collider is one of the major ingredients in the Standard Model investigations being carried on in the context of the experimental programme. Several depolarising effects at beam energies beyond 60 GeV limit the application of the Resonant Depolarisation (RD) method, which provi des an energy uncertainty of about ±1 MeV at the Z0 resonance. Extrapolation techniques from magnetic field measurements are used to obtain beam energies in the W-pair region, aiming at a total energy error £15 MeV. Consistency checks over a large range of precisely calibrated energies are mandatory to contain systematic errors from extrapolation. Progress obtained in extending the polarisable ener gy range in the 1997 LEP Run and the preliminary extrapolation errors are reported