1,329 research outputs found
Alien Registration- Drost, Burnes H. (Caribou, Aroostook County)
https://digitalmaine.com/alien_docs/22644/thumbnail.jp
Kwaliteit van de arbeid in pluimveehouderijsystemen als alternatief voor de legbatterij
Doel van het project is het beoordelen van de kwaliteit van de arbeid in de belangrijkste momenteel bekende huisvestingssystemen voor leghennen (inclusief de batterijhuisvesting). Op basis van deze integrale beoordeling van de arbeidskwaliteit zullen de gezondheidskundige implicaties voor de werkende mensen in elk van die huisvestingssystemen worden aangegeve
Becoming a selfish clan : recombination associated to reverse - transcription in LTR retrotransposons
Drost, Hajk Georg. University of Cambridge. The Sainsbury Laboratory. United Kingdom.Sánchez, Diego H. Universidad de Buenos Aires. Facultad de AgronomÃa. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA). Buenos Aires, Argentina.3382–3392Transposable elements (TEs) are parasitic DNA bits capable of mobilization and mutagenesis, typically suppressed by host’s epigenetic silencing. Since the selfish DNA concept, it is appreciated that genomes are also molded by arms-races against natural TE inhabitants. However, our understanding of evolutionary processes shaping TEs adaptive populations is scarce. Here, we review the events of recombination associated toreverse-transcription in LTR retrotransposons, a process shuffling their genetic variants during replicative mobilization. Current evidence may suggest that recombinogenic retrotransposons could beneficially exploit host suppression, where clan behavior facilitates their speciation and diversification. Novel refinements to retrotransposons life-cycle and evolution models thus emerge
Preliminary Results on Chemical Thinning of Apple Blossoms with Ammonium Thiosulphate, NAA, and Ethephon
Preliminary tests were carried out using ammonium thiosulphate as a chemical thinning agent for apple ('Cox's Orange Pippin' and 'Braeburn') blossoms. Ethephon and NAA (1-napthylacetic acid) were included for comparison. Whole tree sprays of 37g/l ammonium thiosulphate over-thinned 'Cox's Orange Pippin' blossoms and severely scorched blossoms, foliage, and apical meristems. Ethephon at 0.35 g/l also over-thinned, and NAA thinned to an intermediate extent when compared with the controls. When the lower concentration of 3.7 g/l ammonium thiosulphate was directly applied to stamens and styles of 'Braeburn' blossoms by brush, initial fruit set was only 30% that of untreated blossoms. When 0.35 g/I ethephon was directly applied by brush to spur leaves or petals of 'Braeburn' blossoms at pink bud, initial fruit set was only 23% that of untreated blossoms. lt is concluded that ammonium thiosulphate has the potential to thin apple blossoms. Further experiments to define optimum concentrations and spray volumes are needed
Fossil biomass preserved as graphitic carbon in a late paleoproterozoic banded iron formation metamorphosed at more than 550°C
Metamorphism is thought to destroy microfossils, partly through devolatilization and graphitization of biogenic organic matter. However, the extent to which there is a loss of molecular, elemental and isotope signatures from biomass during high-temperature metamorphism is not clearly established. We report on graphitic structures inside and coating apatite grains from the c. 1850 Ma Michigamme silicate banded iron formation from Michigan, metamorphosed above 550°C. Traces of N, S, O, H, Ca and Fe are preserved in this graphitic carbon and X-ray spectra show traces of aliphatic groups. Graphitic carbon has an expanded lattice around 3.6 Å, forms microscopic concentrically-layered and radiating polygonal flakes and has homogeneous δ13C values around −22‰, identical to bulk analyses. Graphitic carbon inside apatite is associated with nanometre-size ammoniated phyllosilicate. Precursors of these metamorphic minerals and graphitic carbon originated from ferruginous clayrich sediments with biomass. We conclude that graphite coatings and inclusions in apatite grains indicate fluid remobilization during amphibolite-facies metamorphism of precursor biomass. This new evidence fills in observational gaps of metamorphosed biomass into graphite and supports the existence of biosignatures in the highly metamorphosed iron formation from the Eoarchean Akilia Association, which dates from the beginning of the sedimentary rock record
Grashoogtemeter, toegepast in onderzoek
Om bij beweidingsproeven een goede schatting van de grasopname te kunnen maken moeten veel waarnemingen gedaan worden. De grashoogtemeter kan daarbij een nuttig instrument zijn
Effecten van het vernevelen van vloeistoffen ter verlaging van de stofconcentratie in pluimveestallen
Het Praktijkonderzoek Pluimveehouderij 'Het Spelderholt' (PP) en het Instituut voor Milieu-en Agritechniek (IMAG-DLO) hebben gezamenlijk onderzoek opgestart naar verlaging van de stofconcentratie in pluimveestallen. Dit heeft geresulteerd in het project 'Effecten van het vernevelen van vloeistoffen ter verlaging van de stofconcentratie in pluimveestallen'. Op basis van een literatuurstudie is binnen dit project gekozen om het terugdringen van de stofconcentratie in pluimveestallen door middel van hetvernevelen van vloeistoffen nader te bekijken
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