Design, Operation, and Calibration of the Canal A Submerged Rectangular Measuring Flume

The D.M.A.D. dam and reservoir are located on the Servier River northeast of Delta, utah, and serve as a stroage reservoir for the winter and spring flows of the Sevier River below Sevier Bridge Reservoir. The D.M.A.D. dam has been constructed with two outlet works, one for feeding Canal A , which serves the Delta and Melville Irrigation Companies, while the other canal serves the Abraham and Desert Irrigation Companies. A gaging station located along Canal A has been used for many years to obtain flow measurements. The gaging station measurements appeared to be very inconsistent, and consequently, in 1963 a study was made to evaluate the accuracy of the station. The results of the study (Figure 1) showed that for a constant depth of flow, the flow rate might vary more than a foot. The flows conveyed by this canal range from 15 to 500 cfs. Canal A is five miles in length and has a total drop in grade of five feet, the average slope therefore being one foot per mile. Regulation of the end of the canal will cause backwater effects over the entire length of the canal. The backwater effects will result in increased seepage losses. The installation of a Parshall flume was contemplated for measuring the flows conveyed by Canal A but it would be necessary to place the floor of the flume 2.75 feet above the canal grade to insure free flow over the entire flow range. The use of such a flume would significantly increase the seepage losses between the measuring station adn the dam for all flows below the design discharge of 500 cfs. Since the D.M.A.D. reservoir is used primarily for regulation, increasing the water levels in Canal A would reduce the regulating head and the usefulness of the lower storage levels in the reservoir for the Delta and Melville Irrigation Companies

Remarkable transmission of microwaves through a wall of long metallic bricks

Copyright © 2001 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 79 (2001) and may be found at http://link.aip.org/link/?APPLAB/79/2844/1The transmitted intensity of a microwave beam through a thick continuous metal wall will be effectively zero due to the almost complete exclusion of the electric field from the metal. However, it is shown here that by removing less than 20% of the wall material to produce a regular array of bricks, up to 90% of the radiation is transmitted, despite the gaps between the bricks being less than 5% of the incident wavelength. This result is attributed to the excitation of a set of resonant waves along the cavity length through the coupling together of surface–plasmon modes across its width

Large-scale structure in a new deep IRAS galaxy redshift survey

We present here the first results from two recently completed, fully sampled redshift surveys comprising 3703 IRAS Faint Source Survey (FSS) galaxies. An unbiased counts-in-cells analysis finds a clustering strength in broad agreement with other recent redshift surveys and at odds with the standard cold dark matter model. We combine our data with those from the QDOT and 1.2 Jy surveys, producing a single estimate of the IRAS galaxy clustering strength. We compare the data with the power spectrum derived from a mixed dark matter universe. Direct comparison of the clustering strength seen in the IRAS samples with that seen in the APM-Stromlo survey suggests b_O/b_I=1.20+/-0.05 assuming a linear, scale independent biasing. We also perform a cell by cell comparison of our FSS-z sample with galaxies from the first CfA slice, testing the viability of a linear-biasing scheme linking the two. We are able to rule out models in which the FSS-z galaxies identically trace the CfA galaxies on scales 5-20h^{-1}Mpc. On scales of 5 and 10h^{-1}Mpc no linear-biasing model can be found relating the two samples. We argue that this result is expected since the CfA sample includes more elliptical galaxies which have different clustering properties from spirals. On scales of 20h^{-1}Mpc no linear-biasing model with b_O/b_I < 1.70 is acceptable. When comparing the FSS-z galaxies to the CfA spirals, however, the two populations trace the same structures within our uncertaintie

HST Imaging Polarimetry of the Gravitational Lens FSC10214+4724

We present imaging polarimetry of the extremely luminous, redshift 2.3 IRAS source FSC10214+4724. The observations were obtained with HST's Faint Object Camera in the F437M filter, which is free of strong emission lines. The 0.7 arcsec long arc is unresolved to 0.04 arcsec FWHM in the transverse direction, and has an integrated polarization of 28 +/- 3 percent, in good agreement with ground-based observations. The polarization position angle varies along the arc by up to 35 deg. The overall position angle is 62 +/- 3 deg east of north. No counterimage is detected to B = 27.5 mag ($3\sigma$), giving an observed arc to counterimage flux ratio greater than 250, considerably greater than the flux ratio of 100 measured previously in the I-band. This implies that the configuration of the object in the source plane at the B-band is different from that at I-band, and/or that the lensing galaxy is dusty.Comment: 17 pages, 3 figures. Accepted for publication in Astronomical Journal, February 199

The SCUBA 8-mJy survey - I: Sub-millimetre maps, sources and number counts

We present maps, source lists, and number counts from the largest, unbiassed, extragalactic sub-mm survey so far undertaken with the SCUBA camera on the JCMT. Our maps cover 260 sq. arcmin, to a noise level S(850)=2.5 mJy/beam. We have reduced the data using both SURF, and our own pipeline which produces zero-footprint maps and noise images. The uncorrelated noise maps produced by the latter approach have allowed application of a maximum-likelihood method to measure the statistical significance of each peak, leading to properly quantified flux-density errors for all potential sources. We detect 19 sources with S/N > 4, 38 with S/N > 3.5, and 72 with S/N > 3. To assess completeness and the impact of source confusion we have applied our source extraction algorithm to a series of simulated images. The result is a new estimate of the sub-mm source counts in the flux-density range S(850)=5-15mJy, which we compare with other estimates, and with model predictions. Our estimate of the cumulative source count at S(850) > 8 mJy is 320 (+80,-100) per square degree. Assuming that the majority of sources have z > 1.5, the co-moving number density of high-z galaxies forming stars at a rate >1000 solar masses per year is 10^-5 per Mpc^3, with only a weak dependence on the precise redshift distribution. This number density corresponds to that of massive ellipticals with L > 3-4 L* at low redshift and is also the same as the co-moving number density of comparably massive, passively-evolving objects in the redshift band 1<z<2 inferred from recent surveys of extremely red objects. Thus the bright sub-mm sources can plausibly account for the formation of all present-day massive ellipticals. Improved z constraints, and a proper measurement of sub-mm clustering can refine or refute this picture.Comment: Minor revisions. 27 pages, 13 figures. Higher resolution versions of Figs 5,6,7 and 8 are available from the autho

A Deep VLA survey at 20cm of the ISO ELAIS survey regions

We have used the Very Large Array(VLA) in C configuration to carry out a sensitive 20cm radio survey of regions of sky that have been surveyed in the Far Infra-Red over the wavelength range 5-200 microns with ISO as part of the European Large Area ISO Survey(ELAIS). As usual in surveys based on a relatively small number of overlapping VLA pointings the flux limit varies over the area surveyed. The survey has a flux limit that varies from a 5$\sigma$ limit of 0.135mJy over an area of 0.12deg$^2$ to a 5$\sigma$ limit of 1.15mJy or better over the whole region covered of 4.22 deg$^2$. In this paper we present the radio catalogue of 867 sources. These regions of sky have previously been surveyed to shallow flux limits at 20cm with the VLA as part of the VLA D configuration NVSS(FWHM=45 arcsec) and VLA B configuration FIRST(FWHM=5 arcsec) surveys. We have carried out a a detailed comparison of the reliability of our own survey and these two independent surveys in order to assess the reliability and completeness of each survey.Comment: 19 pages, 24 figures, submitted to MNRAS, also available in http://www.ast.cam.ac.uk/~ciliegi/elais/paper

The ELAIS deep X-ray survey - I. Chandra source catalogue and first results

We present an analysis of two deep (75 ks) Chandra observations of the European Large Area Infrared Space Observatory (ISO) Survey (ELAIS) fields N1 and N2 as the first results from the ELAIS deep X-ray survey. This survey is being conducted in well-studied regions with extensive multiwavelength coverage. Here we present the Chandra source catalogues along with an analysis of source counts, hardness ratios and optical classifications. A total of 233 X-ray point sources are detected in addition to two soft extended sources, which are found to be associated with galaxy clusters. An overdensity of sources is found in N1 with 30 per cent more sources than N2, which we attribute to large-scale structure. A similar variance is seen between other deep Chandra surveys. The source count statistics reveal an increasing fraction of hard sources at fainter fluxes. The number of galaxy-like counterparts also increases dramatically towards fainter fluxes, consistent with the emergence of a large population of obscured sources

Adolescent dietary patterns are associated with lifestyle family psycho-social factors

Background/ Objectives: Dietary intake during adolescence contributes to lifelong eating habits and the development of early risk factors for disease in adulthood. Few studies have examined the dietary patterns of adolescents and the social and environmental factors that may affect them during this life stage. The present study describes dietary patterns in a cohort of adolescents and examines their associations with socioeconomic factors, as well as parental and adolescent risk factor behaviours. Design: A semi quantitative FFQ was used to assess study adolescents’ usual dietary intake over the previous year. Information was collected on family functioning and various socio economic and risk factor variables via questionnaire. Adolescents visited the clinic for anthropometric measurements. Setting: The Western Australian Pregnancy Cohort Study (Raine Study), Perth, Western Australia. Subjects: Adolescents (n 1631) aged 14 years from a pregnancy cohort study. Results: Factor analysis identified two distinct dietary patterns that differed predominantly in fat and sugar intakes. The ‘Western’ pattern consisted of high intakes of take away foods, soft drinks, confectionery, French fries, refined grains, full fat dairy products and processed meats. The ‘Healthy’’ pattern included high intakes of whole grains, fruit, vegetables, legumes and fish. ANOVA showed that the ‘Western’ dietary pattern was positively associated with greater television viewing and having a parent that smoked, and was inversely associated with family income. The ‘Healthy’’ pattern was positively associated with female gender, greater maternal education, better family functioning and being in a two parent family, and was inversely associated with television viewing. Conclusions: This study suggests that both lifestyle factors and family psycho social environment are related to eating patterns in Australian adolescents