QUARTERLY PREDICTION MODELS FOR LIVE HOG PRICES

Demand and Price Analysis,

U. S. labor supply in the twenty-first century

The American labor force will be transformed as the twenty-first century unfolds, a change that will confront policymakers and business firms with new challenges and new opportunities. The impending slowdown of labor force growth that will accompany the retirement of the baby boom generation already is playing a central role in national debates over the future solvency of Social Security and Medicare, as well as U.S. immigration policies. But labor supply changes will be influenced by other dimensions as well. In the coming decades, American workers are likely to be, on average, older and better educated than today’s labor force. The globalization of labor markets is already opening new employment opportunities for some Americans and changing the wage rates paid to others. The production technologies and personnel policies adopted by tomorrow’s firms will undoubtedly reflect the numbers and types of workers available for employment.Labor supply ; Baby boom generation

Depth-dependent target strengths of gadoids by the boundary-element method

Author Posting. © Acoustical Society of America, 2003. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 114 (2003): 3136-3146, doi:10.1121/1.1619982.The depth dependence of fish target strength has mostly eluded experimental investigation because of the need to distinguish it from depth-dependent behavioral effects, which may change the orientation distribution. The boundary-element method (BEM) offers an avenue of approach. Based on detailed morphometric data on 15 gadoid swimbladders, the BEM has been exercised to determine how the orientation dependence of target strength changes with pressure under the assumption that the fish swimbladder remains constant in shape and volume. The backscattering cross section has been computed at a nominal frequency of 38 kHz as a function of orientation for each of three pressures: 1, 11, and 51 atm. Increased variability in target strength and more abundant and stronger resonances are both observed with increasing depth. The respective backscattering cross sections have been averaged with respect to each of four normal distributions of tilt angle, and the corresponding target strengths have been regressed on the logarithm of fish length. The tilt-angle-averaged backscattering cross sections at the highest pressure have also been averaged with respect to frequency over a 2-kHz band for representative conditions of insonification. For all averaging methods, the mean target strength changes only slightly with depth.This work began with sponsorship by the European Commission through its RTD-program, Contract No. MAS3-CT95-0031 (BASS), and was completed with support by the Office of Naval Research, Contract No. N000140310368

Development of probability of detection data for structural health monitoring damage detection techniques based on acoustic emission

Structural Health Monitoring (SHM) techniques have been developed as a cost effective alternative to currently adopted Non-Destructive Testing (NDT) methods which have well understood levels of performance. Quantitative performance assessment, as used in NDT, needs to be applied to SHM techniques to establish their performance levels as a basis for technique comparison and also as a requirement for practical aerospace application according to set regulations. One such measurand is Probability of Detection (POD). This paper reports experiments conducted to investigate the location accuracy of the Acoustic Emission (AE) system in monitoring events from HsuNielson and fatigue crack AE sources as a route to establish the POD of AE in SHM. It was found that fatigue crack tips could be located at 90% POD within 10 mm accuracy

Estrogen Receptor and Signal Transducer and Activator of Transcription 3 Expression in Equine Mammary Tumors.

Equine mammary tumors are uncommon, and relatively sparse histopathologic and molecular data exist. The present study describes the histopathologic features of 7 such tumors, which exhibited infiltrative growth, intermediate to high mitotic rates, and focally extensive necrosis. The tumors exhibited variably strong staining for vimentin and cytokeratin 14, as well as frequently weak cytoplasmic staining for pan-cytokeratin. E-cadherin expression was strong. Interestingly, a subgroup of the tumors exhibited strong nuclear staining for estrogen receptor α. Three of 7 tumors exhibited nuclear expression of the transcription factor STAT3, suggesting that STAT3 was transcriptionally active. Rare to absent nuclear STAT3 expression was observed in carcinomas exhibiting moderate to intense staining for cytokeratin 14. This investigation confirms previous investigators' assertions that equine mammary tumors have a malignant phenotype. A subset of the equine mammary tumors exhibited estrogen receptor α expression, suggesting that these tumors may potentially have similar molecular characteristics to their feline and canine counterparts.This is the author accepted manuscript. The final version is available from Sage via http://dx.doi.org/10.1177/030098581455940

Calibration of broadband active acoustic systems using a single standard spherical target

Author Posting. © Acoustical Society of America, 2008. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 124 (2008): 128-136, doi:10.1121/1.2917387.When calibrating a broadband active acoustic system with a single standard target such as a sphere, the inherent resonances associated with the scattering by the sphere pose a significant challenge. In this paper, a method is developed which completely eliminates the source of resonances through isolating and exploiting the echo from the front interface of a sphere. This echo is relatively insensitive to frequency over a wide range of frequencies, lacking resonances, and is relatively insensitive to small changes in material properties and, in the case of spherical shells, shell thickness. The research builds upon the concept of using this echo for calibration in the work of Dragonette et al. [J. Acoust. Soc. Am. 69, 1186–1189 (1981)]. This current work generalizes that of Dragonette by (1) incorporating a pulse compression technique to significantly improve the ability to resolve the echo, and (2) rigorously accounting for the scattering physics of the echo so that the technique is applicable over a wide range of frequencies and material properties of the sphere. The utility of the new approach is illustrated through application to data collected at sea with an air-filled aluminum spherical shell and long broadband chirp signals (30–105 kHz).This work was supported by the U.S. Office of Naval Research Grant Nos. N00014-04-1-0475 and N00014- 04-1-0440 and the J. Seward Johnson Chair at WHOI

Review of Non-destructive Testing (NDT) Techniques and their applicability to thick walled composites

A tier 1 automotive supplier has developed a novel and unique kinetic energy recovery storage system for both retro-fitting and OEM application for public transport systems where periodic stop start behaviour is paramount. A major component of the system is a composite flywheel spinning at up to 36,000 rpm (600 Hz). Material soundness is an essential requirement of the flywheel to ensure failure does not occur. The component is particularly thick for a composite being up to 30 mm cross section in some places. The geometry, scale and material make-up pose some challenges for conventional NDT systems. Damage can arise in composite materials during material processing, fabrication of the component or in-service activities among which delamination, cracks and porosity are the most common defects. A number of non-destructive testing (NDT) techniques are effective in testing components for defects without damaging the component. NDT techniques like Ultrasonic Testing, X-Ray, Radiography, Thermography, Eddy current and Acoustic Emission are current techniques for various testing applications. Each of these techniques uses different principles to look into the material for defects. However, the geometry, physical and material properties of the component being tested are important factors in the applicability of a technique. This paper reviews these NDT techniques and compares them in terms of characteristics and applicability to composite parts

Protocols for calibrating multibeam sonar

Author Posting. © Acoustical Society of America, 2005. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 117 (2005): 2013-2027, doi:10.1121/1.1869073.Development of protocols for calibrating multibeam sonar by means of the standard-target method is documented. Particular systems used in the development work included three that provide the water-column signals, namely the SIMRAD SM2000/90- and 200-kHz sonars and RESON SeaBat 8101 sonar, with operating frequency of 240 kHz. Two facilities were instrumented specifically for the work: a sea well at the Woods Hole Oceanographic Institution and a large, indoor freshwater tank at the University of New Hampshire. Methods for measuring the transfer characteristics of each sonar, with transducers attached, are described and illustrated with measurement results. The principal results, however, are the protocols themselves. These are elaborated for positioning the target, choosing the receiver gain function, quantifying the system stability, mapping the directionality in the plane of the receiving array and in the plane normal to the central axis, measuring the directionality of individual beams, and measuring the nearfield response. General preparations for calibrating multibeam sonars and a method for measuring the receiver response electronically are outlined. Advantages of multibeam sonar calibration and outstanding problems, such as that of validation of the performance of multibeam sonars as configured for use, are mentioned.Support by the National Science Foundation through Award No. OCE-0002664, NOAA through Grant No. NA97OG0241, and the Cooperative Institute for Climate and Ocean Research (CICOR) through NOAA Contract No. NA17RJ1223 is acknowledged

Characterisation of cardiac function and RUNX expression in two separate models of heart disease

No abstract available