Annual and seasonal changes in mineral contents (Ca, Mg, P, K and Na) of grazed clover-grass mixtures in organic farming

A grazed field experiment was established in 1995 to evaluate alsike clover (Trifoliun hybridum L.), red clover (Trifolium pratense L.) and white clover (Trifolium repens L.) in clover-grass mixtures under organic farming practices. In this study the effect of seed mixture (alsike clover, red clover, white clover, white and alsike clover or grass mixture), year (1997, 1998) and grazing period (5 per grazing season) on the herbage calcium (Ca), magnesium (Mg), potassium (K) phosphorous (P) and sodium (Na) contents was assessed and the relationships between botanical proportions and herbage mineral contents were studied. Herbage Ca and Na contents varied between the seed mixtures, Ca, Mg, P and Na contents between the years and all measured minerals, except Na, between the grazing periods. The white clover mixture resulted in higher Ca and Na contents. The contents of Ca and Mg were positively related with the proportions of clovers and weeds and were higher in 1997. The contents of P and K were higher in the rainy summer of 1998. The seed mixtures resulted in similar mean K/(Ca + Mg) equivalent ratios, but the Ca/P ratio was higher for the white clover mixture. Mineral rations varied between and within grazing seasons. Under organic practices the supply of minerals in the pasture herbage varied temporally and according to the botanical contents and was unable to meet fully the requirements of dairy cows. Additional mineral feeding is recommended for organic farming systems to balance the dietary mineral contents for grazing cows

\u3ci\u3eUrophora Quadrifasciata\u3c/i\u3e (Diptera: Tephritidae), An Introduced Seedhead Fly New to Midwestern North America

The Old World tephritid Urophora quadrifasciata, a gall-inducing seed- head fly, was released in western and eastern North America for the biological control of knapweeds, Centaurea spp. (Asteraceae). Its establishment in the West (BC, CA, ID, MT, OR, WA) and in the East (CT, MA, MD, NH, NJ, NY, PA, RI, VA, VT, WV) has been previously reported. Collections from eastern Minnesota and western Michigan in 1995 are the first for the Northcentral region of North America

Neutral-ionic phase transition : a thorough ab-initio study of TTF-CA

The prototype compound for the neutral-ionic phase transition, namely TTF-CA, is theoretically investigated by first-principles density functional theory calculations. The study is based on three neutron diffraction structures collected at 40, 90 and 300 K (Le Cointe et al., Phys. Rev. B 51, 3374 (1995)). By means of a topological analysis of the total charge densities, we provide a very precise picture of intra and inter-chain interactions. Moreover, our calculations reveal that the thermal lattice contraction reduces the indirect band gap of this organic semi-conductor in the neutral phase, and nearly closes it in the vicinity of the transition temperature. A possible mechanism of the neutral-ionic phase transition is discussed. The charge transfer from TTF to CA is also derived by using three different technics.Comment: 11 pages, 9 figures, 7 table

Recent OPAL measurements in non-perturbative QCD

Using multihadronic Z0 decays recorded in 1991-1995 by the OPAL detector in e+e- collisions at LEP1, experimental analyses were made of the following subjects: (a) Bose-Einstein correlations; (b) Intermittency and correlations; (c) rho and omega spin alignments; (d) A search for the tensor glueball candidate fj(2200).Comment: 6 pages, 5 Encapsulated Postscript figures, uses APS revtex.sty To be published in the proceedings of American Physical Society (APS) Meeting of the Division of Particles and Fields (DPF99), Los Angeles, CA, 5-9 Jan 199

Wee partons in large nuclei: from virtual dream to hard reality

We construct a weak coupling, many body theory to compute parton distributions in large nuclei for $x\ll A^{-1/3}$. The wee partons are highly coherent, non--Abelian Weizs\"{a}cker--Williams fields. Radiative corrections to the classical results are discussed. The parton distributions for a single nucleus provide the initial conditions for the dynamical evolution of matter formed in ultrarelativistic nuclear collisions.Comment: Plenary talk at Quark Matter '95, Monterey, CA, Jan 1995; LaTex file 16 pages, uses espcrc2.sty; 1 separate uuencoded figure file which uses epsf.st

Higgs Boson And WLWLW_L W_L Scattering At e−e−e^-e^- Colliders

We discuss the Standard-Model Higgs boson production in the channels $e^-e^-\to e^-e^- H$, $e^-\nu W^- H$, and $e^-e^- ZH We also illustrate the enhancements in the$W^-W^-$cross section that would result from a strongly-interacting Higgs sector or from a$H^{--}$resonance in a doublet + triplet scalar field model.Comment: Contribution to the Proceedings of$e^-e^-$ Workshop, Santa Cruz, CA, Sept. 4--5, 1995. 13 pages, 5 figs, LaTeX; postscript file available via anonymous ftp at ftp://ucdhep.ucdavis.edu/han/sews/emem_sc.p