422 research outputs found
A new approach to the investigation of allergenic respirable particles using a modified Anderson Impactor
Pollen allergens have been shown to occur in fine particles much smaller than pollen grains. As such allergenic particles have a high probability of entering the lower human airways, it is important to further investigate their origin and their biological and immunological properties. Accordingly, we have modified the particle collection surface of an Andersen Impactor using adhesive coated microscope slides to enable identification by high resolution microscopic analysis and immunodetection of allergenic particulates.<br /
Crawford Crossing: A Park Concept Plan
85 pagesTurner, Oregon is growing. A new residential development will soon increase the city’s housing stock by about a third, presenting new opportunities for community and economic development in Turner. Among these opportunities is the chance to develop 40 acres around Crawford Lake into a beautiful lakeside park with access to fishing, boating, hiking, picnicking, and outdoor enjoyment. This document outlines a vision and concept for this new park, based on extensive input from Turner area residents both young and old. The City of Turner and interested community groups can use the park design concept and resources presented here as a guide for building out the park over the coming years.
About the Concept Plan
Crawford Lake, located in northern Turner, began its life as a quarry excavated by Riverbend Sand and Gravel. The quarry was retired in 2008 and has gradually filled with water to form what is now the 70- acre Crawford Lake. After almost a decade, the land around the lake is being developed, adding 203 new single family homes and 131 apartment units to the Turner residential community.
The “Crawford Crossing” development offers more than the promise of residential growth: as part of the project, the City of Turner is receiving 40 acres of donated land on the southern end of Crawford Lake to develop as a public park. As Turner grows, the new Crawford Crossing Park will enhance residents’ quality of life by offering access to the lake’s recreational amenities and increasing the availability of natural areas and open spaces for public use.City of Turner, OR; Community Service Cente
Irrigation area, efficiency and water storage mediate the drought resilience of irrigated agriculture in a semi-arid catchment
We examined the effects of hydrological variables such as irrigation area, irrigation efficiency and water storage on the resilience of (mostly commercial) irrigated agriculture to drought in a semi-arid catchment in South Africa. We formulated a conceptual framework termed ‘Water, Efficiency, Resilience, Drought’ (WERD) and an accompanying spreadsheet model. These allow the resilience of irrigated agriculture to drought to be analysed via water accounts and a key resilience indicator termed Days to Day Zero (DDZ). This represents the number of days that a pre- and within-drought supply of catchment water available to irrigation is withdrawn down to zero in the face of a prolonged drought. A higher DDZ (e.g. >300 days) indicates greater resilience whilst a lower DDZ (e.g. <150 days) signals lower resilience. Drought resilience arises through land and water management decisions underpinned by four types of resilience capacities; absorptive, adaptive, anticipative and transformative. For the case study, analyses showed that irrigators, with currently approximately 23,000 ha under irrigation, have historically absorbed and adapted to drought events through construction of water storage and adoption of more efficient irrigation practices resulting in a DDZ of 260 days. However, by not fully anticipating future climate and water-related risks, irrigators are arguably on a maladaptive pathway resulting in water supply gains, efficiency and other practices being used to increase irrigation command areas to 28,000 ha or more, decreasing their capacity to absorb future droughts. This areal growth increases water withdrawals and consumption, further stresses the catchment and reduces future DDZs to approximately 130 days indicating much lower drought resilience. Our approach, supported by supplementary material, allows stakeholders to better understand the resilience consequences of future drought in order to; reconcile competition between rising water demands, consider new water storage; improve agricultural and irrigation planning; and enhance catchment governance
Dynamical Dark Energy or Simply Cosmic Curvature?
We show that the assumption of a flat universe induces critically large
errors in reconstructing the dark energy equation of state at z>~0.9 even if
the true cosmic curvature is very small, O(1%) or less. The spuriously
reconstructed w(z) shows a range of unusual behaviour, including crossing of
the phantom divide and mimicking of standard tracking quintessence models. For
1% curvature and LCDM, the error in w grows rapidly above z~0.9 reaching
(50%,100%) by redshifts of (2.5,2.9) respectively, due to the long cosmological
lever arm. Interestingly, the w(z) reconstructed from distance data and Hubble
rate measurements have opposite trends due to the asymmetric influence of the
curved geodesics. These results show that including curvature as a free
parameter is imperative in any future analyses attempting to pin down the
dynamics of dark energy, especially at moderate or high redshifts.Comment: 5 pages, 2 figures. To appear in JCA
Spectral Energy Distribution of Radio Sources in Nearby Clusters of Galaxies: Implications for Sunyaev-Zel'dovich Effect Surveys
To explore the high frequency radio spectra of galaxies in clusters, we used
NRAO's Very Large Array at four frequencies, 4.9-43 GHz, to observe 139
galaxies in low redshift (z<0.25), X-ray detected, clusters. The clusters were
selected from the survey conducted by Ledlow & Owen, who provided redshifts and
1.4 GHz flux densities for all the radio sources. We find that more than half
of the observed sources have steep microwave spectra as generally expected
(alpha<-0.5, in the convention S \propto nu^alpha). However, 60-70% of the
unresolved or barely resolved sources have flat or inverted spectra. Most of
these show an upward turn in flux at nu>22 GHz, implying a higher flux than
would be expected from an extrapolation of the lower frequency flux
measurements. Our results quantify the need for careful source subtraction in
increasingly sensitive measurements of the Sunyaev-Zel'dovich effect in
clusters of galaxies (as currently being conducted by, for instance, the
Atacama Cosmology Telescope and South Pole Telescope groups).Comment: 16 pages, 10 figures, 5 tables; version published in ApJ; forecast
for SZE surveys changed with respect to previous versio
Observing the Evolution of the Universe
How did the universe evolve? The fine angular scale (l>1000) temperature and
polarization anisotropies in the CMB are a Rosetta stone for understanding the
evolution of the universe. Through detailed measurements one may address
everything from the physics of the birth of the universe to the history of star
formation and the process by which galaxies formed. One may in addition track
the evolution of the dark energy and discover the net neutrino mass.
We are at the dawn of a new era in which hundreds of square degrees of sky
can be mapped with arcminute resolution and sensitivities measured in
microKelvin. Acquiring these data requires the use of special purpose
telescopes such as the Atacama Cosmology Telescope (ACT), located in Chile, and
the South Pole Telescope (SPT). These new telescopes are outfitted with a new
generation of custom mm-wave kilo-pixel arrays. Additional instruments are in
the planning stages.Comment: Science White Paper submitted to the US Astro2010 Decadal Survey.
Full list of 177 author available at http://cmbpol.uchicago.ed
Cosmological parameters from SDSS and WMAP
We measure cosmological parameters using the three-dimensional power spectrum
P(k) from over 200,000 galaxies in the Sloan Digital Sky Survey (SDSS) in
combination with WMAP and other data. Our results are consistent with a
``vanilla'' flat adiabatic Lambda-CDM model without tilt (n=1), running tilt,
tensor modes or massive neutrinos. Adding SDSS information more than halves the
WMAP-only error bars on some parameters, tightening 1 sigma constraints on the
Hubble parameter from h~0.74+0.18-0.07 to h~0.70+0.04-0.03, on the matter
density from Omega_m~0.25+/-0.10 to Omega_m~0.30+/-0.04 (1 sigma) and on
neutrino masses from <11 eV to <0.6 eV (95%). SDSS helps even more when
dropping prior assumptions about curvature, neutrinos, tensor modes and the
equation of state. Our results are in substantial agreement with the joint
analysis of WMAP and the 2dF Galaxy Redshift Survey, which is an impressive
consistency check with independent redshift survey data and analysis
techniques. In this paper, we place particular emphasis on clarifying the
physical origin of the constraints, i.e., what we do and do not know when using
different data sets and prior assumptions. For instance, dropping the
assumption that space is perfectly flat, the WMAP-only constraint on the
measured age of the Universe tightens from t0~16.3+2.3-1.8 Gyr to
t0~14.1+1.0-0.9 Gyr by adding SDSS and SN Ia data. Including tensors, running
tilt, neutrino mass and equation of state in the list of free parameters, many
constraints are still quite weak, but future cosmological measurements from
SDSS and other sources should allow these to be substantially tightened.Comment: Minor revisions to match accepted PRD version. SDSS data and ppt
figures available at http://www.hep.upenn.edu/~max/sdsspars.htm
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