8,565 research outputs found
Illinois occultation summary, 1. 1977 - 1978
Instrumentation and data acquisition techniques used to record lunar occultations at the University of Illinois Prairie Observatory are described. Tables and graphs summarize data from 64 events which include 30 observations of stars brighter than 7th magnitude, 40 reappearances, 4 angular diameter measurements, 8 observations of binary stars, and 6 observations which may indicate multiplicity
Assisting Whole-Farm Decision-Making through Stochastic Budgeting
Stochastic budgeting is used to simulate the business and financial risk and the performance over a six-year planning horizon on a Norwegian dairy farm. A major difficulty with stochastic whole-farm budgeting lies in identifying and measuring dependency relationships between stochastic variables. Some methods to account for these stochastic dependencies are illustrated. The financial feasibility of different investment and management strategies is evaluated. In contrast with earlier studies with stochastic farm budgeting, the option aspect is included in the analysis.Farm Management,
Radio Supernovae in the Great Survey Era
Radio properties of supernova outbursts remain poorly understood despite
longstanding campaigns following events discovered at other wavelengths. After
~ 30 years of observations, only ~ 50 supernovae have been detected at radio
wavelengths, none of which are Type Ia. Even the most radio-loud events are ~
10^4 fainter in the radio than in the optical; to date, such intrinsically dim
objects have only been visible in the very local universe. The detection and
study of radio supernovae (RSNe) will be fundamentally altered and dramatically
improved as the next generation of radio telescopes comes online, including
EVLA, ASKAP, and MeerKAT, and culminating in the Square Kilometer Array (SKA);
the latter should be > 50 times more sensitive than present facilities. SKA can
repeatedly scan large (> 1 deg^2) areas of the sky, and thus will discover RSNe
and other transient sources in a new, automatic, untargeted, and unbiased way.
We estimate SKA will be able to detect core-collapse RSNe out to redshift z ~
5, with an all-redshift rate ~ 620 events yr^-1 deg^-2, assuming a survey
sensitivity of 50 nJy and radio lightcurves like those of SN 1993J. Hence SKA
should provide a complete core-collapse RSN sample that is sufficient for
statistical studies of radio properties of core-collapse supernovae. EVLA
should find ~ 160 events yr^-1 deg^-2 out to redshift z ~ 3, and other SKA
precursors should have similar detection rates. We also provided
recommendations of the survey strategy to maximize the RSN detections of SKA.
This new radio core-collapse supernovae sample will complement the detections
from the optical searches, such as the LSST, and together provide crucial
information on massive star evolution, supernova physics, and the circumstellar
medium, out to high redshift. Additionally, SKA may yield the first radio Type
Ia detection via follow-up of nearby events discovered at other wavelengths.Comment: 21 pages, 5 figures, accepted for publication in Ap
A structure marker study for Pd_2Si formation: Pd moves in epitaxial Pd_2Si
A sample with the configuration Si (111)/single crystalline Pd_2Si/polycrystalline Pd_2Si/Pd is used to study the dominant moving species during subsequent Pd_2Si formation by annealing at 275 °C. The interface between monocrystalline and polycrystalline Pd_2Si is used as a marker to monitor the dominant moving species. The result shows that Pd is the dominant moving species in the monocrystal
A Comparison of Risk Exposure in Aquaculture and Agricultural Businesses
Agriculture and aquaculture have common features associated with their biological nature affecting risk exposure of the businesses. The aim of this paper is to compare risk exposure in salmon farming and agricultural enterprises in Norway by using an implicit error component model to examine the risk structure of yields, prices and economic returns at the farm level. Results indicate a higher farm-level year-to-year variability in yields, prices and economic returns in salmon farming than in agricultural enterprises. The variability in livestock enterprises was generally lower than for crop enterprises. Return on assets was highest in salmon farming with an average annual return of 9.2%. All of the agricultural farm types exhibited a negative average return on assets on average. Stochastic dominance tests of the distribution of economic returns from aquaculture and agricultural farm types showed salmon farming to be the most risk efficient alternative and salmon farming was most attractive from an investor’s perspective.Risk analysis, variability, Norway, Risk and Uncertainty,
Econometric Analysis of the Effects of Subsidies on Farm Production in Case of Endogenous Input Quantities
Replaced with revised version of paper 07/29/09.panel data, subsidies, household model, endogeneity, Norwegian grain farming, Agricultural and Food Policy, Consumer/Household Economics, Production Economics,
Evaluation of a pulsed quasi-steady MPD thruster and associated subsystems
The performance of quasi-steady magnetoplasmadynamic (MPD) thrusters at high power levels is discussed. An axisymmetric configuration is used for the MPD thruster, with various cathode and anode sizes, over a wide range of experimental conditions. Thrust is determined from impulse measurements with current waveforms, while instantaneous measurements are made for all other variables. It is demonstrated that the thrust produced has a predominately self-magnetic origin and is directly proportional to the square of the current. The complete set of impulse measurement data is presented
Stochastic Utility-Efficient Programming of Organic Dairy Farms
Opportunities to make sequential decisions and adjust activities as a season progresses and more information becomes available characterize the farm management process. In this paper, we present a discrete stochastic two-stage utility efficient programming model of organic dairy farms, which includes risk aversion in the decision maker's objective function as well as both embedded risk (stochastic programming with resource) and non-embedded risk (stochastic programming without recourse). Historical farm accountancy data and subjective judgments were combined to assess the nature of the uncertainty that affects the possible consequences of the decisions. The programming model was used within a stochastic dominance framework to examine optimal strategies in organic dairy systems in Norway.agriculture, risk analysis, stochastic programming, stochastic dominance, organic farming, Livestock Production/Industries, Q12, C61,
Life and work on small-scale farms in Norway: an outlook based on survey results linked to financial data
This paper studies what causes (small-scale) farmers to leave their farms and typically move to urban areas. A data set is constructed by linking survey results with financial data, and the data set is analyzed by multivariate statistical techniques. Our results indicate that, while existence and size of future farm production is important, there is also a difference between farmers who primarily have financial objectives for their farming, and those who have more lifestyle oriented objectives. The latter group is, everything else being equal, more likely to stay on the farm. This could imply that, if preventing migration from rural to urban areas is a policy objective, production support schemes will be effective for some groups, but will be less effective for the group with lifestyle objectives. If this group is to be encouraged to stay on the countryside, policies directed at improving the general living conditions in the local community are likely to be more effective than specific support schemes related to agricultural production.migration, farmer objectives, agricultural policy, structural equation modelling, Agricultural and Food Policy, Research Methods/ Statistical Methods,
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