17,919 research outputs found
Development of an image converter of radical design
A long term investigation of thin film sensors, monolithic photo-field effect transistors, and epitaxially diffused phototransistors and photodiodes to meet requirements to produce acceptable all solid state, electronically scanned imaging system, led to the production of an advanced engineering model camera which employs a 200,000 element phototransistor array (organized in a matrix of 400 rows by 500 columns) to secure resolution comparable to commercial television. The full investigation is described for the period July 1962 through July 1972, and covers the following broad topics in detail: (1) sensor monoliths; (2) fabrication technology; (3) functional theory; (4) system methodology; and (5) deployment profile. A summary of the work and conclusions are given, along with extensive schematic diagrams of the final solid state imaging system product
The APM Survey for Cool Carbon Stars in the Galactic Halo - II The Search for Dwarf Carbon Stars
We present proper motion measurements for carbon stars found during the APM
Survey for Cool Carbon Stars in the Galactic Halo (Totten & Irwin, 1998).
Measurements are obtained using a combination of POSSI, POSSII and UKST survey
plates supplemented where necessary by CCD frames taken at the Isaac Newton
Telescope. We find no significant proper motion for any of the new APM
colour-selected carbon stars and so conclude that there are no dwarf carbon
stars present within this sample. We also present proper motion measurements
for three previously known dwarf carbon stars and demonstrate that these
measurements agree favourably with those previously quoted in the literature,
verifying our method of determining proper motions. Results from a
complimentary program of JHK photometry obtained at the South African
Astronomical Observatory are also presented. Dwarf carbon stars are believed to
have anomalous near-infrared colours, and this feature is used for further
investigation of the nature of the APM carbon stars. Our results support the
use of JHK photomtery as a dwarf/giant discriminator and also reinforce the
conclusion that none of the new APM-selected carbon stars are dwarfs. Finally,
proper motion measurements combined with extant JHK photometry are presented
for a sample of previously known Halo carbon stars, suggesting that one of
these stars, CLS29, is likely to be a previously unrecognised dwarf carbon
star.Comment: 13 pages, 5 figures, accepted for publication in MNRAS, Also
available at http://www.astro.keele.ac.uk/~ejt/publications.htm
Using Regression Discontinuity Design to Identify the Effect of Zoning
We test the effect of minimum lot zoning on rural-to-urban land use conversion using Regression Discontinuity Design (RDD), a technique that exploits natural discontinuities in the data to identify causal effects. Observations are drawn from either size of a discontinuous minimum lot size zoning boundary. Using these selected sub-samples, a binary discrete choice model of residential land use change is estimated using parcel-level data and other spatially explicit data from an exurban county that lies on the fringes of Cleveland, Ohio. Results show that controlling for unobserved correlation in the data clearly identifies a negative and significant effect of larger minimum lot size zoning on the probability of conversion to a residential use.Land Economics/Use,
THE VALUE OF CLEAN DAIRY AIR: ACCOUNTING FOR ENDOGENEITY AND SPATIALLY CORRELATED ERRORS IN A HEDONIC ANALYSES OF THE IMPACT OF ANIMAL OPERATIONS ON LOCAL PROPERTY VALUES
We study the effect of livestock operations on property values using a hedonic analysis in five Ohio townships. Unlike previous studies, we account for endogenous livestock location variables and spatially correlated errors. Results suggest failure to correct for these problems results in biased estimates of livestock impacts on property values.Land Economics/Use,
Recommended from our members
Are our children terrorist targets?
Are U.S. children potential terror targets? While such a notion is almost impossible to contemplate, evidence increasingly suggests that U.S. intelligence efforts must be alert to this horrific possibility and that schools and first-responders should have appropriate emergency plans
Recommended from our members
Population Vulnerabilities, Preconditions, and the Consequences of Disasters
In a perfect illustration of our nation's proclivity for postevent crisis response and our resistance to longer term planning and system investment, the nation put a rush order on developing a massive bureaucracy designed to fast track new systems for preventing and responding to terrorism and large scale natural disasters. FEMA and many other agencies were incorporated into the new Department of Homeland Security, billions of dollars were appropriated and, seemingly, a substantial focus on disaster prevention and management was emerging in the aftermath of the attacks on the World Trade Center in New York City. What actually materialized, however, in the frantic push to create new systems, has, so far, failed to provide credible, cost-effective, evidence-based systems of disaster preparedness and response. Overall, I suspect that the government efforts spurred on by the attacks of 9/11 represent not only an extraordinary level of spending, but also a lack of accountability that is virtually unprecedented in recent US history. In fact, after watching—and working among—the efforts to respond effectively to the disasters precipitated by Hurricanes Katrina and Rita, and the subsequent flooding of New Orleans, it is clear that much needs to be done in all aspects of this field. But perhaps no challenge is more pressing than coming to grips with the realities facing families whose "disaster risk profile" is exacerbated by vulnerabilities that include long-term income fragility, social marginalization, or chronic illness
THE PRIVATE SECTOR APPROACH TO GRAIN MARKETING: THE CASE OF AGRICULTURAL MARKET ADVISORY SERVICES
The purpose of this paper is to investigate the pricing performance and behavior of market advisory services in corn and soybeans. Data on corn and soybean net price received for advisory services, as reported by the AgMAS Project, are available for the 1995, 1996 and 1997 marketing years. Performance test results suggest that, on average, market advisory services exhibit a small ability to "beat the market". This conclusion is somewhat sensitive to the type of performance test and market benchmark considered. The predictability results provide little evidence that future advisory service pricing performance can be predicted from past performance. Marketing profiles identify three marketing "styles": i) "scale-up" sales, ii) selective hedging and iii) "speculative" hedging. Advisory services tend to follow the same approach across crop years.Agribusiness,
Recommended from our members
Are We Ready Yet to Deal with Large-Scale Disasters?
What seems to be abundantly clear, however, is that the United States is still not where it should be in terms of the general response capacity following major disasters, whatever their cause. Part of the problem is unchanged from last year. We will have not defined what we mean by "prepared" whether we are speaking of this concept on a national or local level. Not that this is in any way easy. The concept of preparedness or readiness is understood to be arbitrarily determined, so that it is always possible to under or over-prepare for future disasters. No two major events are exactly the same and the consequences can encompass a relatively wide range. That is precisely why it is essential for appropriate officials - particularly on the federal level - to establish criteria for what it means for the nation and for communities to be sufficiently prepared. That definition should take into account the major threats that the U. S. faces, guidelines for appropriate planning on a regional basis and, ultimately, an arbitrary decision with respect to much will be spent on preparing
Chandra Observations of Low Mass X-ray Binaries and Diffuse Gas in the Early-Type Galaxies NGC 4365 and NGC 4382 (M85)
(Abridged) We used the Chandra X-ray Observatory ACIS S3 to image the X-ray
faint elliptical galaxy NGC 4365 and lenticular galaxy NGC 4382. The
observations resolve much of the X-ray emission into 99 and 58 sources,
respectively, most of which are low-mass X-ray binaries (LMXBs) associated with
each of the galaxies. We identify 18 out of the 37 X-ray sources in a central
field in NGC 4365 with globular clusters. The luminosity functions of the
resolved sources for both galaxies are best fit with cutoff power-laws whose
cutoff luminosity is ergs s. These
luminosities are much larger than those previously measured for similar
galaxies; we do not find evidence for a break in the luminosity function at the
Eddington luminosity of a 1.4 neutron star. The spatial distributions
of the resolved sources for both galaxies are broader than the distribution of
optical stars. In both galaxies, a hard power-law model fits the summed
spectrum of all of the sources. The unresolved emission is best fit by the sum
of a soft mekal model representing emission from diffuse gas, and a hard
power-law, presumed to be from unresolved LMXBs. A standard beta model fits the
radial distribution of the diffuse gas in both galaxies. In the elliptical NGC
4365, the best-fit core radius is very small, while the S0 galaxy NGC 4382 has
a larger core radius. This may indicate that the gas in NGC 4382 is rotating
significantly.Comment: Astrophysical Journal, accepted: 38 pages with 20 embedded reduced
resolution Postscript figure
1995 PRICING PERFORMANCE OF MARKET ADVISORY SERVICES FOR CORN AND SOYBEANS
The purpose of this research report is to present an evaluation of advisory service pricing performance in 1995 for corn and soybeans. Specifically, the average price received by a subscriber to an advisory service is calculated for corn and soybean crops harvested in 1995. The average net advisory price across all 25 corn programs is 2.34 per bushel and a maximum of 6.61 per bushel. As with corn, the range of net advisory prices for soybeans is substantial, with a minimum of 7.92 per bushel.Agricultural Market Advisory Service (AgMAS) Project, D4, D7, D8, G1, G2, H4, H8, Q1, Z1, Marketing,
- …
