Effects of forage supplements on milk production and chemical properties, in vivo digestibility, rumen fermentation and N excretion in dairy cows offered red clover silage and corn silage or dry ground corn

peer-reviewedThis study concerned the effects of partial substitution of clover silage with high starch forages on milk production and chemical composition, in vivo digestibility, rumen fermentation pattern and nitrogen excretion of dairy cows. Sixteen dairy cows were separated into two groups and were assigned to treatments in a two-period crossover design. Two forage supplements were used: corn silage (CS) and dry ground corn (DG). All animals received 4.5 kg of concentrate dry matter per day. Results showed no significant difference between the forage supplements for milk production, while significant differences (P<0.01) were observed for milk fat, milk protein and nitrogen utilisation efficiency (42 v. 4.0 g/kg, 3.5 v. 3.3 g/kg and 222 v. 188 g/kg, respectively, for DG and CS). Faecal N excretion did not differ between forage supplements, but urinary N excretion was higher for CS (P<0.05). No significant differences were observed between treatments for rumen fluid pH or for rumen fluid concentrations of ammonium nitrogen or of acetic, propionic or butyric acids. Dry matter intake and the in vivo digestibility of dry matter, organic matter, acid detergent fibre and neutral detergent fibre were all higher for CS compared with DG.The authors are grateful to the Environmental Office of the Cantabrian Government for funding the project 05-640.02-2174

The evolution of the bi-modal colour distribution of galaxies in SDSS groups

We analyse $u-r$ colour distributions for several samples of galaxies in groups drawn from the Fourth Data Release of the Sloan Digital Sky Survey. For all luminosity ranges and environments considered the colour distributions are well described by the sum of two Gaussian functions. We find that the fraction of galaxies in the red sequence is an increasing function of group virial mass. We also study the evolution of the galaxy colour distributions at low redshift, $z\le0.18$ in the field and in groups for galaxies brighter than $M_r-5\log(h)=-20$, finding significant evidence of recent evolution in the population of galaxies in groups. The fraction of red galaxies monotonically increases with decreasing redshift, this effect implies a much stronger evolution of galaxies in groups than in the field.Comment: 7 pages, 6 figures, submited to MNRAS after minor revisio

Classical Analog of Electromagnetically Induced Transparency

We present a classical analog for Electromagnetically Induced Transparency (EIT). In a system of just two coupled harmonic oscillators subject to a harmonic driving force we can reproduce the phenomenology observed in EIT. We describe a simple experiment performed with two linearly coupled RLC circuits which can be taught in an undergraduate laboratory class.Comment: 6 pages, two-column, 6 figures, submitted to the Am. J. Phy

Gamma-Ray Bursts Black hole accretion disks as a site for the vp-process

We study proton rich nucleosynthesis in windlike outflows from gamma-ray bursts accretion disks with the aim to determine if such outflows are a site of the vp-process. The efficacy of this vp-process depends on thermodynamic and hydrodynamic factors. We discuss the importance of the entropy of the material, the outflow rate, the initial ejection point and accretion rate of the disk. In some cases the vp-process pushes the nucleosynthesis out to A~100 and produces light p-nuclei. However, even when these nuclei are not produced, neutrino induced interactions can significantly alter the abundance pattern and cannot be neglected.Comment: 9 pages, 16 figures, accepted for publication in Phys. Rev.

A strategy for the design of skyrmion racetrack memories

Magnetic storage based on racetrack memory is very promising for the design of ultra-dense, low-cost and low-power storage technology. Information can be coded in a magnetic region between two domain walls or, as predicted recently, in topological magnetic objects known as skyrmions. Here, we show the technological advantages and limitations of using Bloch and Neel skyrmions manipulated by spin current generated within the ferromagnet or via the spin-Hall effect arising from a non-magnetic heavy metal underlayer. We found that the Neel skyrmion moved by the spin-Hall effect is a very promising strategy for technological implementation of the next generation of skyrmion racetrack memories (zero field, high thermal stability, and ultra-dense storage). We employed micromagnetics reinforced with an analytical formulation of skyrmion dynamics that we developed from the Thiele equation. We identified that the excitation, at high currents, of a breathing mode of the skyrmion limits the maximal velocity of the memory

Developing Capacity, Skills, and Tobacco Control Networks to address Tobacco-related Disparities: Leadership and Advocacy Institute to Advance Minnesota’s Parity for Priority Populations (LAAMPP)

Priority populations disproportionately experience tobacco-related disparities, despite population level declines in tobacco use. The Leadership and Advocacy Institute to Advance Minnesota’s Parity for Priority Populations (LAAMPP) recruits and trains African immigrants/African Americans, Asian Americans/Pacific Islanders, American Indians, Chicano/Latinos, and LGBTQ community members to develop leaders to address tobacco harms in their communities. This paper describes and evaluates the LAAMPP Institute, and discusses lessons learned through the Institute and future directions for community-based tobacco-control efforts. The mixed-methods evaluation included qualitative key informant interviews with LAAMPP Fellows and community and project contacts, a Skills Assessment Tool, project case studies, and a social network analysis of the Fellows’ tobacco-control social networks at baseline and follow-up. At follow-up, Fellows’ tobacco control networks were larger, more extensive and diverse, and included more actors perceived to be influential in tobacco control. Fellows’ skills increased in core competencies (tobacco control, advocacy, facilitation, collaboration, cultural/community competence) and Fellows used tobacco, advocacy and cultural/community competencies more frequently. Four of five cohorts successfully passed policies. The results of LAAMPP suggest that a cross-cultural leadership institute contributes to the successful development of capacity and leadership skills among priority populations and may be a useful model for others working toward health equity

Landau level spectroscopy of ultrathin graphite layers

Far infrared transmission experiments are performed on ultrathin epitaxial graphite samples in a magnetic field. The observed cyclotron resonance-like and electron-positron-like transitions are in excellent agreement with the expectations of a single-particle model of Dirac fermions in graphene, with an effective velocity of c* = 1.03 x 10^6 m/s.Comment: 4 pages 4 figures Slight revisions following referees' comments. One figure modifie