Strategieën precisiebemesting op gras

In het project Grass4Farming is de afgelopen twee jaar op Dairy Campus en bij maatschap Kroes gewerkt aan een proof of concept voor strategieën (King John en Robin Hood) voor precisiebemesting binnen percelen voor grasland op basis van met sensoren gemeten plaats- en tijdspecifieke bodem- en gewasinformatie.Variabele bemesting in de akkerbouw op basis van bodem- en gewasinformatie wordt gezien als een belangrijke toepassing en het gebruik ervan bij granen en aardappels wordt gestimuleerd. De laatste paar jaar is er steeds meer aandacht voor het gewas gras, om ook daar principes uit de precisielandbouw toe te passen. Bemesting van grasland is complex omdat een melkveehouder binnen een jaar te maken heeft met meerdere oogsten, meerdere percelen, verschillende soorten mest, met en zonder beweiding en een beperkte plaatsingsruimte. De ontwikkelde PerceelVerdeler (http://webapplicaties.wur.nl/software/perceelverdeler) is een handig hulpmiddel om meststoffen zo goed mogelijk te verdelen

Electronic structure and optical properties of lightweight metal hydrides

We study the electronic structures and dielectric functions of the simple hydrides LiH, NaH, MgH2 and AlH3, and the complex hydrides Li3AlH6, Na3AlH6, LiAlH4, NaAlH4 and Mg(AlH4)2, using first principles density functional theory and GW calculations. All these compounds are large gap insulators with GW single particle band gaps varying from 3.5 eV in AlH3 to 6.5 eV in the MAlH4 compounds. The valence bands are dominated by the hydrogen atoms, whereas the conduction bands have mixed contributions from the hydrogens and the metal cations. The electronic structure of the aluminium compounds is determined mainly by aluminium hydride complexes and their mutual interactions. Despite considerable differences between the band structures and the band gaps of the various compounds, their optical responses are qualitatively similar. In most of the spectra the optical absorption rises sharply above 6 eV and has a strong peak around 8 eV. The quantitative differences in the optical spectra are interpreted in terms of the structure and the electronic structure of the compounds.Comment: 13 pages, 10 figure

“The Neuroscience of Responsibility”—Workshop Report

This is a report on the 3-day workshop “The Neuroscience of Responsibility” that was held in the Philosophy Department at Delft University of Technology in The Netherlands during February 11th–13th, 2010. The workshop had 25 participants from The Netherlands, Germany, Italy, UK, USA, Canada and Australia, with expertise in philosophy, neuroscience, psychology, psychiatry and law. Its aim was to identify current trends in neurolaw research related specifically to the topic of responsibility, and to foster international collaborative research on this topic. The workshop agenda was constructed by the participants at the start of each day by surveying the topics of greatest interest and relevance to participants. In what follows, we summarize (1) the questions which participants identified as most important for future research in this field, (2) the most prominent themes that emerged from the discussions, and (3) the two main international collaborative research project plans that came out of this meeting

The Maybe Stream: A Possible Cold Stellar Stream in the Ultra-Diffuse Galaxy NGC1052-DF2

We report tentative evidence for a cold stellar stream in the ultra-diffuse galaxy NGC1052-DF2. If confirmed, this stream (which we refer to as "The Maybe Stream") would be the first cold stellar stream detected outside of the Local Group. The candidate stream is very narrow and has an unusual and highly curved shape.Comment: Accepted for publication in RNAA

A galaxy lacking dark matter

Studies of galaxy surveys in the context of the cold dark matter paradigm have shown that the mass of the dark matter halo and the total stellar mass are coupled through a function that varies smoothly with mass. Their average ratio M_{halo}/M_{stars} has a minimum of about 30 for galaxies with stellar masses near that of the Milky Way (approximately 5x10^{10} solar masses) and increases both towards lower masses and towards higher masses. The scatter in this relation is not well known; it is generally thought to be less than a factor of two for massive galaxies but much larger for dwarf galaxies. Here we report the radial velocities of ten luminous globular-cluster-like objects in the ultra-diffuse galaxy NGC1052-DF2, which has a stellar mass of approximately 2x10^8 solar masses. We infer that its velocity dispersion is less than 10.5 kilometers per second with 90 per cent confidence, and we determine from this that its total mass within a radius of 7.6 kiloparsecs is less than 3.4x10^8 solar masses. This implies that the ratio M_{halo}/M_{stars} is of order unity (and consistent with zero), a factor of at least 400 lower than expected. NGC1052-DF2 demonstrates that dark matter is not always coupled with baryonic matter on galactic scales.Comment: To appear in the 29 March issue of Natur

Hematopoietic Stem Cell Transplantation after Reduced Intensity Conditioning in Acute Myelogenous Leukemia Patients Older Than 40 Years

AbstractReduced intensity conditioning (RIC) protocols are increasingly used for allogeneic hematopoietic stem cell transplantation (HSCT) in elderly patients. We analyzed the outcome of RIC HSCT in acute myelogenous leukemia (AML) patients over the age of 40 years. Forty-three AML or high-risk myelodysplastic syndrome (MDS) patients were treated with a fludarabine and low-dose total-body irradiation (TBI)-based pretransplantation regimen. Donors were HLA-compatible sibling (68%) or unrelated volunteers (34%). All but 2 AML patients were in complete remission (CR) at the time of transplantation. Seventy-six percent of patients had a poor risk profile. Hematologic recovery was fast, and primary graft failure occurred in 1 patient. Two patients with active disease at the time of HSCT experienced ongoing relapse. Infections were diagnosed in 9 patients (21%), and 6 patients (14%) were treated for cytomegalovirus (CMV) reactivation. Sixty percent of patients developed acute graft-versus-host disease (aGVHD), which was grade II in 40% and grade III in 12%. The cumulative incidence of chronic graft-versus-host disease (cGVHD) was 33% at 1 and at 2 years. Treatment-related mortality (TRM) was low (9%), total nonrelapse mortality (NRM) was 19%. After a median follow-up of 571 days, 16 patients (37%) experienced relapse. Median disease-free and overall survival (DFS; OS) were 24 and 31 months, respectively. There were no differences in complications and outcome between recipients of sibling and unrelated grafts. In conclusion, fludarabine plus low-dose TBI-based RIC HSCT is effective in AML patients over the age of 40 years without active disease at the time of transplant and is associated with low TRM

A Revised Velocity for the Globular Cluster GC-98 in the Ultra Diffuse Galaxy NGC1052-DF2

We recently published velocity measurements of luminous globular clusters in the galaxy NGC1052-DF2, concluding that it lies far off the canonical stellar mass - halo mass relation. Here we present a revised velocity for one of the globular clusters, GC-98, and a revised velocity dispersion measurement for the galaxy. We find that the intrinsic dispersion $\sigma=5.6^{+5.2}_{-3.8}$ km/s using Approximate Bayesian Computation, or $\sigma=7.8^{+5.2}_{-2.2}$ km/s using the likelihood. The expected dispersion from the stars alone is ~7 km/s. Responding to a request from the Editors of ApJ Letters and RNAAS, we also briefly comment on the recent analysis of our measurements by Martin et al. (2018).Comment: Published in the Research Notes of the AAS. 2 pages, 1 figur