2,056 research outputs found
Manganese carbonyl-mediated reactions of azabutadienes with phenylacetylene, methyl acrylate and other unsaturated molecules
Reaction of PhCH₂Mn(CO)₅ with l,4-di-aryl-1-aza-1,3-butadienes gave substituted pyrrolinonyl rings which were η⁴-coordinated to a Mn(CO)₃ group. These are formed by intramolecular CO insertion into a (non-isolated) cyclomanganated intermediate, followed by cyclisation. Other unsaturated reagents (PhC≡CH, CH2=CHCOOMe, PhNCO) gave products arising from insertion of these, including a structurally characterised tri-aryl-η⁵-azacyclohexadienyl-Mn(CO)₃ complex from the reaction with the alkyne.
PhCH₂Mn(CO)₅ reacts with l,4-di-aryl-1-aza-1,3-butadienes in the presence of unsaturated substrates to give products based on a cyclomanganated intermediate
Expression profiles of genes regulating dairy cow fertility: recent findings, ongoing activities and future possibilities
Subfertility has negative effects for dairy farm profitability, animal welfare and sustainability of animal production. Increasing herd sizes and economic pressures restrict the amount of time that farmers can spend on counteractive management Genetic improvement will become increasingly important to restore reproductive performance. Complementary to traditional breeding value estimation procedures, genomic selection based on genome-wide information will become more widely applied. Functional genomics, including transcriptomics (gene expression profiling), produces the information to understand the consequences of selection as it helps to unravel physiological mechanisms underlying female fertility traits. Insight into the latter is needed to develop new effective management strategies to combat subfertility. Here, the importance of functional genomics for dairy cow reproduction so far and in the near future is evaluated. Recent gene profiling studies in the field of dairy cow fertility are reviewed and new data are presented on genes that are expressed in the brains of dairy cows and that are involved in dairy cow oestrus (behaviour). Fast-developing new research areas in the field of functional genomics, such as epigenetics, RNA interference, variable copy numbers and nutrigenomics are discussed including their promising future value for dairy cow fertility
The Horseshoe Estimator: Posterior Concentration around Nearly Black Vectors
We consider the horseshoe estimator due to Carvalho, Polson and Scott (2010)
for the multivariate normal mean model in the situation that the mean vector is
sparse in the nearly black sense. We assume the frequentist framework where the
data is generated according to a fixed mean vector. We show that if the number
of nonzero parameters of the mean vector is known, the horseshoe estimator
attains the minimax risk, possibly up to a multiplicative constant. We
provide conditions under which the horseshoe estimator combined with an
empirical Bayes estimate of the number of nonzero means still yields the
minimax risk. We furthermore prove an upper bound on the rate of contraction of
the posterior distribution around the horseshoe estimator, and a lower bound on
the posterior variance. These bounds indicate that the posterior distribution
of the horseshoe prior may be more informative than that of other one-component
priors, including the Lasso.Comment: This version differs from the final published version in pagination
and typographical detail; Available at
http://projecteuclid.org/euclid.ejs/141813426
Efficient all-optical production of large Li quantum gases using D gray-molasses cooling
We use a gray molasses operating on the D atomic transition to produce
degenerate quantum gases of Li with a large number of atoms. This
sub-Doppler cooling phase allows us to lower the initial temperature of 10
atoms from 500 to 40 K in 2 ms. We observe that D cooling remains
effective into a high-intensity infrared dipole trap where two-state mixtures
are evaporated to reach the degenerate regime. We produce molecular
Bose-Einstein condensates of up to 510 molecules and
weakly-interacting degenerate Fermi gases of 10 atoms at
with a typical experimental duty cycle of 11 seconds.Comment: 5 pages, 3 figure
De overheid als 'Change Agent' voor ISA
Onaangepaste en hoge snelheden zijn belangrijke factoren aangaande verkeersonveiligheid en leefbaarheid. Diverse maatregelen, zoals aanpassingen aan de infrastructuur, informatiecampagnes en handhaving worden reeds toegepast. Er wordt daarentegen nog nauwelijks gebruik gemaakt van in-car maatregelen zoals Intelligente Snelheids Aanpassing (ISA) voor het terugdringen van snelheid. De effecten van ISA blijken positief maar nog steeds is er weinig sprake van een coherente implementatie. Aangezien de effecten zich voornamelijk op het maatschappelijke vlak voordoen en veranderingen in de bestaande processen teweeg brengen is de overheid de meest aangewezen partij om als “Change Agent” op te treden in het realiseren van een gerichte implementatie. Stappen die de overheid zou moeten nemen zijn het creëren van de noodzakelijke voorwaarden, het onder de aandacht brengen van de positieve effecten van ISA bij de direct betrokkenen, en het bepalen van de wijze van implementatie
Microstructure and Rheology of Lamellar Liquid Crystalline Phases
We have investigated the microstructure and rheological properties of ternary surfactant mixtures in a salt solution. The surfactants were 6% sodium 4-dodecylbenzenesulfonate, 3% C13-15 ethoxylated alcohol with seven ethylene oxide (EO) units and 1% C13-15 ethoxylated alcohol with 2, 4, 7, 9, 11, 14, 20, or 25 EO units. The salt solution was 10% nitrilotriacetate·H2O. Microstructural investigations (electron microscopy, light microscopy, confocal laser microscopy, conductivity measurements, and centrifugation) show that at rest the samples containing the surfactant with 2 EO to 9 EO units are dispersions of lamellar droplets (curved surfactant bilayers). The samples containing the surfactant with 11 EO to 25 EO units show a continuous lamellar structure (sheets of surfactant bilayers) with a small amount of lamellar droplets present. The change in several rheological parameters reflects this change in microstructure. The power law index from flow experiments at low shear rates changes from 0.1 for the lamellar dispersions to 0.4 for the continuous lamellar phases. Similar changes are observed in shear modulus and in the limiting strain for linear viscoelastic behavior. The continuous lamellar phase is converted to droplets by shearing at rates above 1 s-1. The continuous lamellar structures will recover in about a week when the samples are allowed to relax. The nature of the droplets is highly dynamic. Confocal laser microscopy shows small fluctuations in droplet shape on a time scale of about 100 s. This time coincides with a characteristic time of around 100 s pertaining to a (shallow) peak in G''
The miniJPAS survey : A preview of the Universe in 56 colors
The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) will scan thousands of square degrees of the northern sky with a unique set of 56 filters using the dedicated 2.55 m Javalambre Survey Telescope (JST) at the Javalambre Astrophysical Observatory. Prior to the installation of the main camera (4.2 deg(2) field-of-view with 1.2 Gpixels), the JST was equipped with the JPAS-Pathfinder, a one CCD camera with a 0.3 deg(2) field-of-view and plate scale of 0.23 arcsec pixel(-1). To demonstrate the scientific potential of J-PAS, the JPAS-Pathfinder camera was used to perform miniJPAS, a similar to 1 deg(2) survey of the AEGIS field (along the Extended Groth Strip). The field was observed with the 56 J-PAS filters, which include 54 narrow band (FWHM similar to 145 angstrom) and two broader filters extending to the UV and the near-infrared, complemented by the u, g, r, i SDSS broad band filters. In this miniJPAS survey overview paper, we present the miniJPAS data set (images and catalogs), as we highlight key aspects and applications of these unique spectro-photometric data and describe how to access the public data products. The data parameters reach depths of mag(AB) similar or equal to 22-23.5 in the 54 narrow band filters and up to 24 in the broader filters (5 sigma in a 3 '' aperture). The miniJPAS primary catalog contains more than 64 000 sources detected in the r band and with matched photometry in all other bands. This catalog is 99% complete at r = 23.6 (r = 22.7) mag for point-like (extended) sources. We show that our photometric redshifts have an accuracy better than 1% for all sources up to r = 22.5, and a precision of 2. The miniJPAS survey demonstrates the capability of the J-PAS filter system to accurately characterize a broad variety of sources and paves the way for the upcoming arrival of J-PAS, which will multiply this data by three orders of magnitude.Peer reviewe
- …