Some Constraints On the Effects of Age and Metallicity on the Low Mass X-ray Binary Formation Rate

We have studied the low mass X-ray binary (LMXB) populations within and outside globular clusters (GC) in NGC 4365 and NGC 3115. Using published age and metallicity constraints from optical and IR observations of their GCs, we do not find any evidence for an increase in the LMXB formation rate in the intermediate age cluster population of NGC 4365, as has been proposed in some scenarios of dynamical LMXB formation in GCs. The old, metal-rich, red population of GCs in NGC 3115 on the other hand is {\it at least} three times as efficient at creating LMXBs as the old, metal-poor, blue clusters. These data suggest that the higher formation efficiency of LMXBs in the red GC subsystems of many galaxies is largely a consequence of their higher metallicity. A comparison of the densities of field LMXBs in different galaxies does not reveal an obvious correlation with the age of the field stars as predicted by models in which the LMXB formation rate in the field drops monotonically with time after an initial burst. This suggests that either a significant fraction of the field LMXBs are created in GCs and subsequently injected into the field, or the LMXB formation rate has a more complex time evolution pattern.Comment: Accepted for publication in ApJ Letters. 7 pages including 5 figure

Range-resolved signal processing for fibre segment interferometry applied to dynamic long-gauge length strain sensing

A range-resolved interferometric signal processing technique using sinusoidal optical frequency modulation is applied to fibre segment interferometry. Here, six optical fibre segments of gauge length 12.5 cm are used as interferometric strain sensors and are formed between seven weak, broadband fibre Bragg gratings, acting as in-fibre partial reflectors. In a very simple and cost-effective optical setup using injection current modulation of a laser diode source, interferometric measurement of acoustic wave propagation in a metal rod is used to demonstrate the capabilities of the technique

EVALUATION OF ALTERNATIVE RISK SPECIFICATIONS IN FARM PROGRAMMING MODELS

The use of alternative probability density functions to specify risk in farm programming models is explored and compared to a traditional specification using historical data. A method is described that compares risk efficient crop mixes using stochastic dominance techniques to examine impacts of different risk specifications on farm plans. Results indicate that a traditional method using historical farm data is as efficient for risk averse producers as two other methods of incorporating risk in farm programming models when evaluated using second degree stochastic dominance. Stochastic dominance with respect to a function further discriminates among the distributions, indicating that a density function based on the historic forecasting accuracy of the futures market results in a more risk-efficient crop mix for highly risk averse producers. Results also illustrate the need to validate alternative risk specifications perceived as improvements to traditional methods.Risk and Uncertainty,

Economic Evaluation of Wind Energy as an Alternative to Natural Gas Powered Irrigation

High natural gas prices have agricultural producers searching for alternative energy sources for irrigation. The economic feasibility of electric and hybrid (electric/wind) systems are evaluated as alternatives to natural gas powered irrigation. Texas Panhandle and Southern Kansas farms are assessed with a quarter-mile sprinkler system, three crops, and two pumping lifts. Breakeven points identify the price at which conversion from a natural gas irrigation system to an electric or hybrid system is cost effective. Results indicate electricity is a more feasible energy source for irrigation and policy changes such as net metering are necessary to make hybrid systems viable.electricity, irrigation, natural gas, wind energy, Agribusiness, Community/Rural/Urban Development, Environmental Economics and Policy, Farm Management, International Development, Land Economics/Use, Research and Development/Tech Change/Emerging Technologies, Resource /Energy Economics and Policy, Q12, Q20, Q42,

Economic Analysis of Manure Harvesting Equipment in Feedyards for Dust Control

This study concentrated on one method of dust control which is harvesting manure with equipment. An economic analysis including hourly fixed and operational costs were performed on the following: tractor-pulled box scraper, front-end loader, dump truck, spreader truck, elevating scraper and tractor-pulled end dump. The purpose of this study was to generate cost data for feedyard owners/operators to reference when making manure management and equipment purchasing decisions.manure harvesting equipment, tractor-pulled box scraper, front-end loader, dump truck, spreader truck, tractor-pulled end dump, Agribusiness, Environmental Economics and Policy,

Teleseismic mechanism of the May 02, 1983 Coalinga, California, earthquake from long-period P-waves

Teleseismic, long-period P-waveforms are modeled to obtain estimates of the source parameters for the May 2, 1983 Coalinga earthquake. The best fitting focal mechanism is: strike = 297 ± 5°, dip = 64 ± 1°, rake = 70 ± 10°. The moment is estimated to be 3.8 ± 1.5 X 10^(25) dyne-cm with a slip duration of 5 ± 1 sec. The depth is estimated at 12 ± 2 km

Simultaneous laser vibrometry on multiple surfaces with a single beam system using range-resolved interferometry

A novel range-resolved interferometric signal processing technique that uses sinusoidal optical frequency modulation is applied to multi-surface vibrometry, demonstrating simultaneous optical measurements of vibrations on two surfaces using a single, collimated laser beam, with a minimum permissible distance of 3.5 cm between surfaces. The current system, using a cost-effective laser diode and a fibre-coupled, downlead insensitive setup, allows an interferometric fringe rate of up to 180 kHz to be resolved with typical displacement noise levels of 8 pm Hz-0.5. In this paper, the system is applied to vibrometry measurements of a table-top cryostat, with concurrent measurements of the optical widow and the sample holder inside. This allows the separation of common-mode vibrations of the whole cryostat from differential vibrations between the window and the sample holder.EPSR

Rupture history of the 1984 Morgan Hill, California, earthquake from the inversion of strong motion records

Near-source strong motion velocity records and teleseismic short-period P waveforms are modeled to obtain the spatial and temporal distribution of slip for the 1984 Morgan Hill earthquake. Both forward modeling and constrained, least-squares inversion techniques are used to interpret the strong motion velocity waveforms in the frequency range of approximately 0.2 to 2.0 Hz. These data support a nearly unilateral rupture to the southeast with a rupture propagation velocity of nine-tenths of the local S-wave velocity. The majority of the slip occurs over a fault length of 25 km and to a first approximation can be interpreted as two main source regions, each with an extent of about 5 km with their centers separated by about 12 km. However, each of the sources has detailed structure of its own, and a simple two-point-source model is not an accurate representation of the Morgan Hill earthquake. The second source occurs about 4.5 sec after the first and is approximately 3 times larger. The maximum dislocation on the fault plane is about 1 m. The total moment of the earthquake is estimated to be 2.1 × 10^(25) dyne-cm. The Morgan Hill earthquake offers convincing evidence for very inhomogeneous slip and stress distributions on shallow strike-slip faults

Failure of self-similarity for large (M_w > 8 1/4) earthquakes

We compare teleseismic P-wave records for earthquakes in the magnitude range from 6.0 to 9.5 with synthetics for a self-similar, ω^2 source model and conclude that the energy radiated by very large earthquakes (M_w > 8 1/4) is not self-similar to that radiated from smaller earthquakes (M_w < 8 1/4). Furthermore, in the period band from 2 sec to several tens of seconds, we conclude that large subduction earthquakes have an average spectral decay rate of ω^(-1.5). This spectral decay rate is consistent with a previously noted tendency of the ω^2 model to overestimate Ms for large earthquakes

Economic Analysis of a Water Truck for Feedyard Dust Suppression

Dust created in feedyards can adversely affect cattle performance. Dust suppression can be accomplished by moistening pen surfaces with traveling gun(s) sprinklers, solid-set sprinklers, and water trucks. This study specifically addresses the fixed and operational costs associated with a water truck for various sized feedyards.water truck, dust suppression, fixed costs, operational costs, Farm Management, Livestock Production/Industries,