258 research outputs found
4MOST Consortium Survey 3: Milky Way Disc and Bulge Low-Resolution Survey (4MIDABLE-LR)
The mechanisms of the formation and evolution of the Milky Way are encoded in
the orbits, chemistry and ages of its stars. With the 4MOST MIlky way Disk And
BuLgE Low-Resolution Survey (4MIDABLE-LR) we aim to study kinematic and
chemical substructures in the Milky Way disc and bulge region with samples of
unprecedented size out to larger distances and greater precision than
conceivable with Gaia alone or any other ongoing or planned survey. Gaia gives
us the unique opportunity for target selection based almost entirely on
parallax and magnitude range, hence increasing the efficiency in sampling
larger Milky Way volumes with well-defined and effective selection functions.
Our main goal is to provide a detailed chrono-chemo-kinematical extended map of
our Galaxy and the largest Gaia follow-up down to magnitudes (Vega).
The complex nature of the disc components (for example, large target densities
and highly structured extinction distribution in the Milky Way bulge and disc
area), prompted us to develop a survey strategy with five main sub-surveys that
are tailored to answer the still open questions about the assembly and
evolution of our Galaxy, while taking full advantage of the Gaia data.Comment: Part of the 4MOST issue of The Messenger, published in preparation of
4MOST Community Workshop, see http://www.eso.org/sci/meetings/2019/4MOST.htm
The sintering behavior of close-packed spheres
The sintering behavior and microstructural evolution of a powder compact is influenced strongly by initial properties, such as the relative density, the particle and pore size distribution, and the powder packing. While the influence of the former parameters on the microstructural evolution has been investigated in some detail, the impact of the initial packing of the powder has been mostly overlooked. However, research has shown that the sintering behavior of a powder can be significantly improved if the powder is regularly packed.
This has been shown for monodisperse spherical TiO2 particles [1], which sintered 10 times faster and exhibited almost no grain growth compared to ordinary TiO2. Similar observations has been made for homogeneously packed Al2O3 [2], SiO2 [3], as well as a number of other materials [4]. Monodispersed spherical TiO2 particles have been shown to order in face-centered cubic (fcc) arrays, while the SiO2 powder forms stacked planes of hexagonal close-packed (hcp) particles. Close packing of monodispersed silica has also been observed [5]. Sintering of two-dimensional close packing cylinders has also been demonstrated experimentally [6–8] and numerically modeled [9,10], and the sintering of particle clusters in three dimensions has also been studied [11]
Synthesis of CdS and CdSe nanocrystallites using a novel single-molecule precursors approach
The synthesis of CdS and CdSe nanocrystallites using the thermolysis of several dithioor
diselenocarbamato complexes of cadmium in trioctylphosphine oxide (TOPO) is reported.
The nanodispersed materials obtained show quantum size effects in their optical spectra
and exhibit near band-edge luminescence. The influence of experimental parameters on
the properties of the nanocrystallites is discussed. HRTEM images of these materials show
well-defined, crystalline nanosized particles. Standard size fractionation procedures can
be performed in order to narrow the size dispersion of the samples. The TOPO-capped CdS
and CdSe nanocrystallites and simple organic bridging ligands, such as 2,2¢-bipyrimidine,
are used as the starting materials for the preparation of novel nanocomposites. The optical
properties shown by these new nanocomposites are compared with those of the starting
nanodispersed materials
Alternative and complementary therapies in osteoarthritis and cartilage repair
Osteoarthritis (OA) is the most common joint condition and, with a burgeoning ageing population, is due to increase in prevalence. Beyond conventional medical and surgical interventions, there are an increasing number of ‘alternative’ therapies. These alternative therapies may have a limited evidence base and, for this reason, are often only afforded brief reference (or completely excluded) from current OA guidelines. Thus, the aim of this review was to synthesize the current evidence regarding autologous chondrocyte implantation (ACI), mesenchymal stem cell (MSC) therapy, platelet-rich plasma (PRP), vitamin D and other alternative therapies. The majority of studies were in knee OA or chondral defects. Matrix-assisted ACI has demonstrated exceedingly limited, symptomatic improvements in the treatment of cartilage defects of the knee and is not supported for the treatment of knee OA. There is some evidence to suggest symptomatic improvement with MSC injection in knee OA, with the suggestion of minimal structural improvement demonstrated on MRI and there are positive signals that PRP may also lead to symptomatic improvement, though variation in preparation makes inter-study comparison difficult. There is variability in findings with vitamin D supplementation in OA, and the only recommendation which can be made, at this time, is for replacement when vitamin D is deplete. Other alternative therapies reviewed have some evidence (though from small, poor-quality studies) to support improvement in symptoms and again there is often a wide variation in dosage and regimens. For all these therapeutic modalities, although controlled studies have been undertaken to evaluate effectiveness in OA, these have often been of small size, limited statistical power, uncertain blindness and using various methodologies. These deficiencies must leave the question as to whether they have been validated as effective therapies in OA (or chondral defects). The conclusions of this review are that all alternative interventions definitely require clinical trials with robust methodology, to assess their efficacy and safety in the treatment of OA beyond contextual and placebo effects
Rock size‐frequency distributions on Mars and implications for Mars Exploration Rover landing safety and operations
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95449/1/jgre1686.pd
Kepler Eclipsing Binary Stars. Vii. The Catalog Of Eclipsing Binaries Found In The Entire Kepler Data Set
The Kepler mission has provided unprecedented, nearly continuous photometric data of ~200,000 objects in the ~105 deg2 field of view (FOV) from the beginning of science operations in May of 2009 until the loss of the second reaction wheel in May of 2013. The Kepler Eclipsing Binary Catalog contains information including but not limited to ephemerides, stellar parameters, and analytical approximation fits for every known eclipsing binary system in the Kepler FOV. Using target pixel level data collected from Kepler in conjunction with the Kepler Eclipsing Binary Catalog, we identify false positives among eclipsing binaries, i.e., targets that are not eclipsing binaries themselves, but are instead contaminated by eclipsing binary sources nearby on the sky and show eclipsing binary signatures in their light curves. We present methods for identifying these false positives and for extracting new light curves for the true source of the observed binary signal. For each source, we extract three separate light curves for each quarter of available data by optimizing the signal-to-noise ratio, the relative percent eclipse depth, and the flux eclipse depth. We present 289 new eclipsing binaries in the Kepler FOV that were not targets for observation, and these have been added to the catalog
Preparation and bactericidal effect of composites based on crosslinked copolymers containing silver nanoparticles
Meeting of the Ecosystem Approach Correspondence Group on on Pollution Monitoring (CorMon Pollution)
In accordance with the UNEP/MAP Programme of Work adopted by COP 21 for the biennium 2020-2021, the United Nations Environment Programme/Mediterranean Action Plan-Barcelona Convention Secretariat (UNEP/MAP) and its Programme for the Assessment and Control of Marine Pollution in the Mediterranean (MED POL) organized the Meeting of the Ecosystem Approach Correspondence Group on Pollution Monitoring (CorMon on Pollution Monitoring). The Meeting was held via videoconference on 26-27 April 2021.
2. The main objectives of the Meeting were to:
a) Review the Monitoring Guidelines/Protocols for IMAP Common Indicator 18, as well as the Monitoring Guidelines/Protocols for Analytical Quality Assurance and Reporting of Monitoring Data for IMAP Common Indicators 13, 14, 17, 18 and 20;
b) Take stock of the state of play of inter-laboratory testing and good laboratory practice related to IMAP Ecological Objectives 5 and 9;
c) Analyze the proposal for the integration and aggregation rules for IMAP Ecological Objectives 5, 9 and 10 and assessment criteria for contaminants and nutrients;
d) Recommend the ways and means to strengthen implementation of IMAP Pollution Cluster towards preparation of the 2023 MED Quality Status Report
4MOST Scientific Operations
The 4MOST instrument is a multi-object spectrograph that will address
Galactic and extragalactic science cases simultaneously by observing targets
from a large number of different surveys within each science exposure. This
parallel mode of operation and the survey nature of 4MOST require some distinct
4MOST-specific operational features within the overall operations model of ESO.
The main feature is that the 4MOST Consortium will deliver, not only the
instrument, but also contractual services to the user community, which is why
4MOST is also described as a facility. This white paper concentrates on
information particularly useful to answering the forthcoming Call for Letters
of Intent.Comment: Part of the 4MOST issue of The Messenger, published in preparation of
4MOST Community Workshop, see http://www.eso.org/sci/meetings/2019/4MOST.htm
Structures and Properties of Newton Black Films Characterized Using Molecular Dynamics Simulations
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