Strategic Alliances in the U.S. Beef Supply Chain

This study analyzes vertical-coordination practices in the U.S. beef supply chain focusing on strategic alliances. We present results from a survey of beef alliances describing their organizational structure, the nature of participantsÂ’' involvement, contractual requirements, information-sharing practices, services offered to alliance participants, and marketing strategies. Survey results provide a detailed description of 13 beef alliances and are intended to inform potential participants about vertical-coordination alternatives. In addition, the study provides relevant information for future economic research on the formation, organization, and functioning of beef alliances.Livestock Production/Industries, Marketing,

Dissolution experiments of commercial PWR (52 MWd/kgU) and BWR (53 MWd/kgU) spent nuclear fuel cladded segments in bicarbonate water under oxidizing conditions. Experimental determination of matrix and instant release fraction

The denominated instant release fraction (IRF) is considered in performance assessment (PA) exercises to govern the dose that could arise from the repository. A conservative definition of IRF comprises the total inventory of radionuclides located in the gap, fractures, and the grain boundaries and, if present, in the high burn-up structure (HBS). The values calculated from this theoretical approach correspond to an upper limit that likely does not correspond to what it will be expected to be instantaneously released in the real system. Trying to ascertain this IRF from an experimental point of view, static leaching experiments have been carried out with two commercial UO2 spent nuclear fuels (SNF): one from a pressurized water reactor (PWR), labelled PWR, with an average burn-up (BU) of 52 MWd/kgU and fission gas release (FGR) of 23.1%, and one from a boiling water reactor (BWR), labelled BWR, with an average BU of and 53 MWd/kgU and FGR of 3.9%.; One sample of each SNF, consisting of fuel and cladding, has been leached in bicarbonate water during one year under oxidizing conditions at room temperature (25 +/- 5) degrees C. The behaviour of the concentration measured in solution can be divided in two according to the release rate. All radionuclides presented an initial release rate that after some days levels down to a slower second one, which remains constant until the end of the experiment. Cumulative fraction of inventory in aqueous phase (FIAPc) values has been calculated. Results show faster release in the case of the PWR SNF. In both cases Np, Pu, Am, Cm, Y, Tc, La and Nd dissolve congruently with U, while dissolution of Zr, Ru and Rh is slower. Rb, Sr, Cs and Mo, dissolve faster than U. The IRF of Cs at 10 and 200 days has been calculated, being (3.10 +/- 0.62) and (3.66 +/- 0.73) for PWR fuel, and (035 +/- 0.07) and (0.51 +/- 0.10) for BWR fuel. (C) 2015 Elsevier B.V. All rights reserved.Peer ReviewedPostprint (author's final draft

Herschel/PACS photometry of transiting-planet host stars with candidate warm debris disks

Dust in debris disks is produced by colliding or evaporating planetesimals, remnants of the planet formation process. Warm dust disks, known by their emission at < 24 micron, are rare (4% of FGK main sequence stars) and especially interesting because they trace material in the region likely to host terrestrial planets, where the dust has a very short dynamical lifetime. Statistical analyses of the source counts of excesses as found with the mid-IR Wide Field Infrared Survey Explorer (WISE) suggest that warm-dust candidates found for the Kepler transiting-planet host-star candidates can be explained by extragalactic or galactic background emission aligned by chance with the target stars. These statistical analyses do not exclude the possibility that a given WISE excess could be due to a transient dust population associated with the target. Here we report Herschel/PACS 100 and 160 micron follow-up observations of a sample of Kepler and non-Kepler transiting-planet candidates' host stars, with candidate WISE warm debris disks, aimed at detecting a possible cold debris disk in any of them. No clear detections were found in any one of the objects at either wavelength. Our upper limits confirm that most objects in the sample do not have a massive debris disk like that in beta Pic. We also show that the planet-hosting star WASP-33 does not have a debris disk comparable to the one around eta Crv. Although the data cannot be used to rule out rare warm disks around the Kepler planet-hosting candidates, the lack of detections and the characteristics of neighboring emission found at far-IR wavelengths support an earlier result suggesting that most of the WISE-selected IR excesses around Kepler candidate host stars are likely due to either chance alignment with background IR-bright galaxies and/or to interstellar emission.Comment: 8 pages, 3 figures, accepted for publication at Astronomy & Astrophysics on 4 August 201

Stellar proper motion and the timing of planetary transits

Duration and period of transits in extrasolar planetary systems can exhibit long-term variations for a variety of reasons. Here we investigate how systemic proper motion, which steadily re-orients planetary orbit with respect to our line of sight, affects the timing of transits. We find that in a typical system with a period of several days proper motion at the level of 100 mas/yr makes transit duration vary at a rate ~10-100 ms/yr. In some isolated systems this variation is at the measurable level (can be as high as 0.6 s/yr for GJ436) and may exceed all other transit timing contributions (due to the general relativity, stellar quadrupole, etc.). In addition, proper motion causes evolution of the observed orbital period via the Shklovskii effect at a rate $\gtrsim 10$ $\mu$s/yr for the nearby transiting systems (0.26 ms/yr in GJ436), which in some cases exceeds all other contributions to $\dot P$. Earth's motion around the Sun gives rise to additional periodic timing signal (even for systems with zero intrinsic proper motion) allowing a full determination of the spatial orientation of the planetary orbit. Unlike most other timing effects the proper motion signatures persist even in systems with zero eccentricity and get stronger as the planetary period increases. They should be the dominant cause of transit timing variations in isolated wide separation (periods of months) systems that will be sought by Kepler.Comment: 7 pages, 2 tables, submitted to Ap

Improving Students\u27 Speaking Skill Using Sign And Notice Pictures AS Media

This Classroom Action Research is conducted to improve students\u27 speaking skill using sign and notice pictures. The subject of this research was 6th grader of SDS Budi Baik Pontianak in academic year 2014/2015 in class A consisted of 22 students. This research was done in 3 cycles. To obtain the data, the writer administered speaking practice test in every cycle to know students\u27 improvement. The writer used observation checklist and field notes to collect the data and reflection of each cycle. The research finding showed that the use of sign and notice pictures as media improved students\u27 speaking skill, as shown in the mean score in each cycle. In Cycle 1, their mean score was 59.54 which categorized as “Poor to Average”, then in Cycle 2 their mean score was 74.78 which categorized as “Average to Good” and in Cycle 3 their mean score was 87.59 which categorized as “Good to Excellent”. Observation checklist and field note also showed improvement in teaching learning activity. In conclusion, the use of sign and notice pictures in as media improved speaking skill of 6th grade students in SDS Budi Baik Pontianak in academic year 2014/2015