Use of Native Grassland in Small-Scale Dairy Systems in the Highlands of Central Mexico. A Case Study

Small-scale dairy systems in Mexico comprise 78% of specialized dairy farms and provide 37% of national production. They are small farms with herds 3-35 cows plus replacements, and rely on family labour (Posadas-Domínguez et al., 2014). In the highlands, many farms have native grasslands, grazed during the rainy season, and supplemented with other feeds as maize straw, maize grain and maize ears. Native grasslands have not been studied in this context. This is a case study on the use of native grassland in a small-scale dairy farm. The objective was to determine how native grasslands are integrated in feeding milking dairy cows, and the feeding costs involved

Effect of Supplementation of Dairy Cows under Cut and Carry or Grazing of Irrigated Cultivated Pastures in Small Scale Dairy Systems in the Highlands of Central Mexico

Small-scale dairy systems in Mexico represent over 78% of dairy farms and produce 37% of the nation’s milk, and have an important role in reducing rural poverty. Small-scale dairy systems are defined by having herds of 3 to 35 cows plus replacements, and rely mostly on the family for labour. In the central highlands, many small-scale dairy farms base the feeding of herds on irrigated cultivated pastures of ryegrass (Lolium multiflorum, L. perenne) – white clover (Trifolium repens), mostly under cut-and-carry by hand with scythes, straws, and large amounts of commercial compound concentrates that result in high feeding costs and low economic sustainability (Fadul-Pacheco et al., 2013). One option to optimize the use of resources in these systems is to change the use of grasslands to intensive grazing that result in lower feeding costs when compared to cut-and-carry strategies. Also, the high protein content of pasture may meet requirements for moderate yields by dairy cows, so that commercial concentrates may be substituted by lower protein, lower cost supplements like ground maize grain and remove the straws of the diets

Comparative proteomic analysis of spermatozoa isolated by swim-up or density gradient centrifugation

Abstract BACKGROUND: Reports about the morphologic and functional characteristics of spermatozoa prepared by density gradient centrifugation (DC) or swim-up (SU) have produced discordant results. We have performed a proteomic comparison of cells prepared by DC and SU providing a molecular insight into the differences between these two methods of sperm cell isolation. METHODS: Protein maps were obtained by 2-dimensional (2-D) separations consisting of isoelectrofocusing (IEF) from pI 3 to 11 followed by SDS-polyacrylamide gel electrophoresis. 2-D gels were stained with Sypro Ruby. Map images of DC and SU spermatozoa were compared using dedicated software. Intensities of a given spot were considered different between DC and SU when their group mean differed by >1.5-fold (p<0.05, Anova). RESULTS: No differences were observed for 853 spots, indicating a 98.7% similarity between DC and SU. Five spots were DC>SU and 1 was SU>DC. Proteins present in 3 of the differential spots could be identified. One DC>SU spot contained lactate dehydrogenase C and gamma-glutamylhydrolase, a second DC>SU spot contained fumarate hydratase and glyceraldehyde-3-phosphate dehydrogenase-2, and a SU>DC spot contained pyruvate kinase M1/M2. CONCLUSIONS: The differences in protein levels found on comparison of DC with SU spermatozoa indicate possible dissimilarities in their glycolytic metabolism and DNA methylation and suggest that DC cells may have a better capacitation potential

Physiological roles of macrophages

Macrophages are present in mammals from midgestation, contributing to physiologic homeostasis throughout life. Macrophages arise from yolk sac and foetal liver progenitors during embryonic development in the mouse and persist in different organs as heterogeneous, self-renewing tissue-resident populations. Bone marrow-derived blood monocytes are recruited after birth to replenish tissue-resident populations and to meet further demands during inflammation, infection and metabolic perturbations. Macrophages of mixed origin and different locations vary in replication and turnover, but are all active in mRNA and protein synthesis, fulfilling organ-specific and systemic trophic functions, in addition to host defence. In this review we emphasise selected properties and non-immune functions of tissue macrophages which contribute to physiologic homeostasis

The atypical iron-coordination geometry of cytochrome f remains unchanged upon binding to plastocyanin, as inferred by XAS

The transient complex between cytochrome f and plastocyanin from the cyanobacterium Nostoc sp. PCC 7119 has been analysed by X-ray Absorption Spectroscopy in solution, using both proteins in their oxidized and reduced states. Fe K-edge data mainly shows that the atypical metal coordination geometry of cytochrome f, in which the N-terminal amino acid acts as an axial ligand of the heme group, remains unaltered upon binding to its redox partner, plastocyanin. This fact suggests that cytochrome f provides a stable binding site for plastocyanin and minimizes the reorganization energy required in the transient complex formation, which could facilitate the electron transfer between the two redox partners

Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the Tevatron

The combination of searches performed by the CDF and D0 collaborations at the Fermilab Tevatron Collider for neutral Higgs bosons produced in association with b quarks is reported. The data, corresponding to 2.6 fb-1 of integrated luminosity at CDF and 5.2 fb-1 at D0, have been collected in final states containing three or more b jets. Upper limits are set on the cross section multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson. Significant enhancements to the production of Higgs bosons can be found in theories beyond the standard model, for example in supersymmetry. The results are interpreted as upper limits in the parameter space of the minimal supersymmetric standard model in a benchmark scenario favoring this decay mode.Comment: 10 pages, 2 figure

Journal Staff

We present the first measurements of the differential cross section d sigma/dp(T)(gamma) for the production of an isolated photon in association with at least two b-quark jets. The measurements consider photons with rapidities vertical bar y(gamma)vertical bar &lt; 1.0 and transverse momenta 30 &lt; p(T)(gamma) &lt; 200 GeV. The b-quark jets are required to have p(T)(jet) &gt; 15 GeVand vertical bar y(jet)vertical bar &lt; 1.5. The ratio of differential production cross sections for gamma + 2 b-jets to gamma + b-jet as a function of p(T)(gamma) is also presented. The results are based on the proton-antiproton collision data at root s = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. The measured cross sections and their ratios are compared to the next- to- leading order perturbative QCD calculations as well as predictions based on the k(T)- factorization approach and those from the sherpa and pythia Monte Carlo event generators

Search for first generation leptoquark pair production in the electron + missing energy + jets final state

We present a search for the pair production of first generation scalar leptoquarks (LQ) in data corresponding to an integrated luminosity of 5.4 fb$^{-1}$ collected with the D0 detector at the Fermilab Tevatron Collider in ppbar collisions at $\sqrt{s}=1.96$ TeV. In the channel $LQ \bar{LQ} \rightarrow e\nu_e qq'$, where q, q' are u or d quarks, no significant excess of data over background is observed, and we set a 95% C.L. lower limit of 326 GeV on the leptoquark mass, assuming equal probabilities of leptoquark decays to eq and $\nu_e q'$.Comment: 7 pages, 6 figures, submitted to PRD-R

Search for the standard model and a fermiophobic Higgs boson in diphoton final states

We present a search for the standard model Higgs boson and a fermiophobic Higgs boson in the diphoton final states based on 8.2 fb-1 of ppbar collisions collected with the D0 detector at the Fermilab Tevatron Collider. No excess of data above background predictions is observed and upper limits at the 95% C.L. on the cross section multiplied by the branching fraction are set which are the most restrictive to date. A fermiophobic Higgs boson with a mass below 112.9 GeV is excluded at the 95% C.L.Comment: 12 pages, 21 figures, submitted to PR

A search for charged massive long-lived particles

We report on a search for charged massive long-lived particles (CMLLPs), based on 5.2 fb$^{-1}$ of integrated luminosity collected with the D0 detector at the Fermilab Tevatron $p\bar{p}$ collider. We search for events in which one or more particles are reconstructed as muons but have speed and ionization energy loss $(dE/dx)$ inconsistent with muons produced in beam collisions. CMLLPs are predicted in several theories of physics beyond the standard model. We exclude pair-produced long-lived gaugino-like charginos below 267 GeV and higgsino-like charginos below 217 GeV at 95% C.L., as well as long-lived scalar top quarks with mass below 285 GeV.Comment: submitted to Phys. Rev. Letter