Determination of Chilling Requirement of Arkansas Thornless Blackberry Cultivars

Little research has been done to determine the chilling requirement for blackberry cultivars. However, field observations from areas where fewer hours of chilling occur indicate that ‘Navaho’ requires more hours of chilling than does ‘Arapaho’. The objective of our study was to determine a method for measuring the chilling requirement using whole plants of two blackberry cultivars, Arapaho and Navaho. One-year old, bare-root plants were field-dug on 26 October 1999 and placed in a cold chamber at 3ºC. Ten single-plant replications of each cultivar were removed at 100-hour intervals up to 1000 hours. The plants were potted and placed in a greenhouse (daily minimum temperature 15ºC), and plants were arranged on benches in a completely randomized design. Budbreak was recorded on a weekly basis. Data for budbreak were analyzed as a two-factor factorial (2 cultivars and 10 chilling treatments) by SAS and means were separated by least significant difference (P = 0.05). Data indicated that the chilling requirement for Arapaho is between 400 and 500 hours. For Navaho, the data indicated the chilling requirement was between 800 and 900 hours. These data support previous observations and indicate that the method used was successful in determining the chilling requirement for blackberries

Alfalfa Products as Roughage and Protein Sources for Corn and Corn Stover Beef Diets

New feeds are continually being developed, especially from by-products of an industrial process which produces a product already in demand. For example, soybean oil meal was initially a by-product of an extraction process for soybean oil, a product in great demand at the time as the base material of paints. As the demand for the oil subsided, the by-product, soybean oil meal, assumed the major role as a protein supplement for livestock. Alfalfa, on the other hand, has always been an important feedstuff, as well as many of its related products such as alfalfa leaf meal and dehydrated alfalfa. The continuous demand for high quality protein sources in human and animal diets has caused an intensive search for protein from many plant sources, including alfalfa. It has been found that, if the soluble alfalfa leaf proteins are removed (Pro-Xan process) for use in poultry diets or for preparation of milk replacers, a rather high protein by-product still remains. This by-product, press cake, could be a valuable feed supplement for lower grade feedstuffs. An explanation of this protein extraction process may be helpful in estimating the feeding value of the alfalfa plant components. Pro-Xan is a leaf protein concentrate extracted from freshly cut alfalfa. In this process, the material is macerated and compressed to remove the soluble (green) juices. The fibrous by-product is termed press cake. The soluble (green) juices undergo further processing to remove the high protein fraction, Pro-Xan. The remaining (brown) juices may or may not be added back into the press cake fraction. The more fibrous by-product, press cake, might be a suitable feedstuff for ruminants, either as a roughage source or as a low level protein source. Numerous studies have already been conducted on the benefits of the Pro-Xan fraction. Press cake, the by-product of the Pro-Xan process, has been studied very little and has no established market as the feed value has yet to be established. The experiments reported here were designed to determine the feeding value of press cake in relation to alfalfa hay and dehydrated alfalfa as protein and roughage sources for ruminants. With the advent of the large packaging systems, corn stover can be transported easily from the field to the feedlot, thus providing the opportunity to also establish the feeding value of corn stover in winter growing rations as well as to compare the two methods of handling corn stover, stacked or ensiled. Growing steers were utilized in this experiment, as their requirements for protein were much higher than with animals in later stages of growth. When feeding high-concentrate rations, as in the second experiment, the roughage portion need not be of high quality, since the digestibility of fiber decreases rapidly as the concentrate portion of the diet exceeds 30%. This provides an opportunity to use a variety of fibrous materials to replace more expensive choices of roughages such as dehydrated alfalfa or high-quality alfalfa hay as long as the protein values are similar. Because corn is normally considered adequate in protein for finishing steers, the protein content of the alfalfa products was not as critical to this experiment as the roughage additions. In this study, press cake was compared to dehydrated alfalfa and alfalfa hay

Three-dimensional simulations of the orientation and structure of reconnection X-lines

This work employs Hall magnetohydrodynamic (MHD) simulations to study the X-lines formed during the reconnection of magnetic fields with differing strengths and orientations embedded in plasmas of differing densities. Although random initial perturbations trigger the growth of X-lines with many orientations, at late time a few robust X-lines sharing an orientation reasonably consistent with the direction that maximizes the outflow speed, as predicted by Swisdak and Drake [Geophys. Res. Lett., 34, L11106, (2007)], dominate the system. The existence of reconnection in the geometry examined here contradicts the suggestion of Sonnerup [J. Geophys. Res., 79, 1546 (1974)] that reconnection occurs in a plane normal to the equilibrium current. At late time the growth of the X-lines stagnates, leaving them shorter than the simulation domain.Comment: Accepted by Physics of Plasma

Diamond degradation in hadron fields

The energy dependence of the concentration of primary displacements induced by protons and pions in diamond has been calculated in the energy range 50 MeV - 50 GeV, in the frame of the Lindhard theory. The concentrations of primary displacements induced by protons and pions have completely different energy dependencies: the proton degradation is very important at low energies, and is higher than the pion one in the whole energy range investigated, with the exception of the delta33 resonance region. Diamond has been found, theoretically, to be one order of magnitude more resistant to proton and pion irradiation in respect to silicon.Comment: 7 pages, 3 figure

The different origins of magnetic fields and activity in the Hertzsprung gap stars, OU Andromedae and 31 Comae

Context: When crossing the Hertzsprung gap, intermediate-mass stars develop a convective envelope. Fast rotators on the main sequence, or Ap star descendants, are expected to become magnetic active subgiants during this evolutionary phase. Aims: We compare the surface magnetic fields and activity indicators of two active, fast rotating red giants with similar masses and spectral class but diferent rotation rates - OU And (Prot=24.2 d) and 31 Com (Prot=6.8 d) - to address the question of the origin of their magnetism and high activity. Methods: Observations were carried out with the Narval spectropolarimeter in 2008 and 2013.We used the least squares deconvolution technique to extract Stokes V and I profiles to detect Zeeman signatures of the magnetic field of the stars. We provide Zeeman-Doppler imaging, activity indicator monitoring, and a precise estimation of stellar parameters. We use stellar evolutionary models to infer the evolutionary status and the initial rotation velocity on the main sequence. Results: The detected magnetic field of OU And is a strong one. Its longitudinal component Bl reaches 40 G and presents an about sinusoidal variation with reversal of the polarity. The magnetic topology of OU And is dominated by large scale elements and is mainly poloidal with an important dipole component, and a significant toroidal component. The detected magnetic field of 31 Com is weaker, with a magnetic map showing a more complex field geometry, and poloidal and toroidal components of equal contributions. The evolutionary models show that the progenitors of OU And and 31 Com must have been rotat Conclusions: OU And appears to be the probable descendant of a magnetic Ap star, and 31 Com the descendant of a relatively fast rotator on the main sequence.Comment: 16 pages, 12 figure

Some Pattern Recognition Challenges in Data-Intensive Astronomy

We review some of the recent developments and challenges posed by the data analysis in modern digital sky surveys, which are representative of the information-rich astronomy in the context of Virtual Observatory. Illustrative examples include the problems of an automated star-galaxy classification in complex and heterogeneous panoramic imaging data sets, and an automated, iterative, dynamical classification of transient events detected in synoptic sky surveys. These problems offer good opportunities for productive collaborations between astronomers and applied computer scientists and statisticians, and are representative of the kind of challenges now present in all data-intensive fields. We discuss briefly some emergent types of scalable scientific data analysis systems with a broad applicability.Comment: 8 pages, compressed pdf file, figures downgraded in quality in order to match the arXiv size limi

The application of airborne imaging radars (L and X-band) to earth resources problems

For abstract, see N75-24064

Exploring the Time Domain With Synoptic Sky Surveys

Synoptic sky surveys are becoming the largest data generators in astronomy, and they are opening a new research frontier, that touches essentially every field of astronomy. Opening of the time domain to a systematic exploration will strengthen our understanding of a number of interesting known phenomena, and may lead to the discoveries of as yet unknown ones. We describe some lessons learned over the past decade, and offer some ideas that may guide strategic considerations in planning and execution of the future synoptic sky surveys.Comment: Invited talk, to appear in proc. IAU SYmp. 285, "New Horizons in Time Domain Astronomy", eds. E. Griffin et al., Cambridge Univ. Press (2012). Latex file, 6 pages, style files include