We analyse deep images from the VISTA survey of the Magellanic Clouds in the
$YJ{K_{\rm s}}$
filters, covering 14 deg2 (10 tiles), split into 120 subregions, and comprising the main body and Wing of ...the Small Magellanic Cloud (SMC). We apply a colour–magnitude diagram reconstruction method that returns their best-fitting star formation rate SFR(t), age–metallicity relation (AMR), distance and mean reddening, together with 68 per cent confidence intervals. The distance data can be approximated by a plane tilted in the East–West direction with a mean inclination of 39°, although deviations of up to ±3 kpc suggest a distorted and warped disc. After assigning to every observed star a probability of belonging to a given age–metallicity interval, we build high-resolution population maps. These dramatically reveal the flocculent nature of the young star-forming regions and the nearly smooth features traced by older stellar generations. They document the formation of the SMC Wing at ages <0.2 Gyr and the peak of star formation in the SMC Bar at ∼40 Myr. We clearly detect periods of enhanced star formation at 1.5 and 5 Gyr. The former is possibly related to a new feature found in the AMR, which suggests ingestion of metal-poor gas at ages slightly larger than 1 Gyr. The latter constitutes a major period of stellar mass formation. We confirm that the SFR(t) was moderately low at even older ages.
An algorithm of satellite formation flying control in the Low-Earth Orbit using the aerodynamic force is considered. A simple model of the aerodynamic force that takes into account the lift component ...of the force is proposed. It allows us to calculate the satellite attitude relative to the incoming flow that provides the required aerodynamic force. For the given model parameters the acceptable control region is obtained. The relative motion control algorithm based on the Linear-Quadratic Regulator is considered. The technique for the algorithm parameters determination is suggested. Numerical study of the controlled motion is carried out. The simulation takes into account the second harmonic of the Earth gravitational field and the inaccuracy of the atmospheric density model.
•An algorithm of formation flying control using differential lift and drag is studied.•At given parameters of the force model the acceptable control region is obtained.•An algorithm parameters adjustment technique is proposed.•A numerical study taking into account disturbances and uncertainties is carried out.
The World Health Organization (WHO) and the International Labour Organization (ILO) are developing a joint methodology for estimating the national and global work-related burden of disease and injury ...(WHO/ILO joint methodology), with contributions from a large network of experts. Here, we present the protocol for two systematic reviews of parameters for estimating the number of disability-adjusted life years of cataracts from occupational exposure to solar ultraviolet radiation, to inform the development of the WHO/ILO joint methodology.
We aim to systematically review studies on occupational exposure to solar ultraviolet radiation (Systematic Review 1) and systematically review and meta-analyse estimates of the effect of occupational exposure to solar ultraviolet radiation on the development of cataract (Systematic Review 2), applying the Navigation Guide systematic review methodology as an organizing framework and conducting both systematic reviews in tandem and in a harmonized way.
Separately for Systematic Reviews 1 and 2, we will search electronic academic databases for potentially relevant records from published and unpublished studies, including Ovid Medline, PubMed, EMBASE, and Web of Sciences. We will also search electronic grey literature databases, Internet search engines and organizational websites; hand search reference list of previous systematic reviews and included study records; and consult additional experts.
We will include working-age (≥15 years) workers in WHO and/or ILO Member States, but exclude children (<15 years) and unpaid domestic workers. For Systematic Review 1, we will include quantitative studies on the prevalence of relevant levels of occupational exposure to solar ultraviolet radiation and of the total working time spent outdoors from 1960 to 2018, stratified by sex, age, country and industrial sector or occupation. For Systematic Review 2, we will include randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies with an estimate of the effect of any occupational exposure to solar ultraviolet radiation (i.e. ≥30 Jm−2/day of occupational solar UV exposure at the surface of the eye) on the prevalence or incidence of cataract, compared with the theoretical minimum risk exposure level (i.e. <30 Jm−2/day of occupational solar UV exposure at the surface of the eye).
At least two review authors will independently screen titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. At least two review authors will assess risk of bias and the quality of evidence, using the most suited tools currently available. For Systematic Review 2, if feasible, we will combine relative risks using meta-analysis. We will report results using the guidelines for accurate and transparent health estimates reporting (GATHER) for Systematic Review 1 and the preferred reporting items for systematic reviews and meta-analyses guidelines (PRISMA) for Systematic Review 2.
PROSPERO registration: CRD42018098897.
•WHO and ILO are developing a joint methodology for estimating the national and global work-related burden of disease and injury.•This article presents a protocol for two systematic reviews for the development of this WHO/ILO joint methodology.•Prevalence studies on occupational exposure to solar ultraviolet radiation will be systematically reviewed.•Studies on effects of occupational exposure to solar ultraviolet radiation on cataract will be systematically reviewed and meta-analysed.
The thermal shock resistance of alumina ceramics with a fine-crystalline structure (crystal size 5 – 40 μm) and with a layered-granular structure, as well as
t
-ZrO
2
–Cr
(40 vol. %)
cermet, was ...studied. Layered-granular ceramics consisted of randomly oriented layered granules, including alternating dense fine-crystalline layers and porous layers made of corundum microballoons. The cermet structure is represented by two interpenetrating continuous skeletons formed from chromium grains and
t
-ZrO
2
grains. To assess the thermal shock resistance, in addition to the known criteria
R
0
,
R
1
it is proposed to use new criteria
R
0
*
,
R
1
*
and the kinetic characteristic of fracture γ
F
/γ
I
. These criteria were compared with the thermal shock resistance determined by the number of thermal cycles to failure
N
of samples and by the method of local thermal shock, which determines the relative loss of crack resistance of the sample after a single thermal cycle
R
T
. Layered-granular Al
2
O
3
-ceramics exhibit the best thermal shock resistance due to the discrete and high-energy destruction mechanism. The use of chromium in the composition of cermet made it possible to significantly increase its thermal shock resistance in comparison with the thermal shock resistance of the ceramic component due to the presence of a heat-conducting metal component. It is shown that the application of the new criteria
R
0
*
and
R
1
*
makes it possible to reliably predict the thermal shock resistance of the studied materials from the indicators
N
and
R
T
.
The possibility of material surfaces restructuring on the nanoscale due to ultrashort laser pulses has recently found a number of practical applications. It was found experimentally that under ...spatial confinement due to a liquid layer atop the surface, one can achieve even finer and cleaner structures as compared to that in air or in vacuum. The mechanism of the materials restructuring under the liquid confinement, however, is not clear and its experimental study is limited by the extreme conditions realized during the intense and localized laser energy deposition that takes place on nanometer spatial and picosecond time-scales. In this theoretical work, we suggest a molecular dynamics-based approach that is capable of simulating the processes of periodic nanostructuring with ultrashort UV laser pulse on metals. The theoretical results of the simulations are directly compared with the experimental data on the same spatial and temporal scales.
Here we present a theoretical work on short pulse laser interaction with metal targets. With the help of Two Temperature Model we consider in detail the interplay of two competitive mechanism of the ...laser deposited energy dissipation: the fast electron heat conduction and the electron–phonon interaction processes. For a range of pulse durations the modelling included a complex description of these processes as the functions of the electron and phonon temperatures. It was shown that for transitional type of metals the maximum surface temperature determined for a range of pulse durations at fixed fluence exhibits peak behavior and the corresponding pulse duration is close to the electron–phonon relaxation time. In contrast, having complex deviation of heat conductivity from its linear growth with the electronic temperature, the group of noble metals shows different behavior in maximum surface temperature depending on the fluence regime. Based on the results, an experimental approach in measuring the electron–phonon relaxation time is suggested and a general tendency of photo-mechanical versus photo-thermal damage of metal targets is deduced.
Damage in textile composites is closely connected with the internal micro- and meso-geometry of the reinforcement, and reveals features, which are not present in the damage processes in classical ...laminates. This paper proposes a test sequence intended to characterise damage in textile composites – its initiation and development different scale levels: (1) Tensile tests on samples cut in characteristic directions of the textile reinforcement (machine, cross and bias), accompanied with acoustic emission (AE) registration and full-field strain measurement on the surface. The test produces stress–strain diagrams and identifies characteristic strain levels for post-mortem investigation: just after first damage
ε
1; well-developed damage
ε
2; just before the final fracture of the sample
ε
3. Full-field strain measurement highlights the relation between strain concentrations (linked with the damage initiation) and the reinforcement structure. (2) Samples loaded up to
ε
1…3 are examined with CT and X-ray. This reveals the damage pattern and allows quantitative characterising of the damage development. (3) Optical and SEM examination of cross-sections through the damage sites, determined with X-ray, identifies local damage modes. The same strain levels are further used for setting up fatigue tests. The experimental protocol is applied for triaxial braided and quasi-UD composites.
A small number of rare, recurrent genomic copy number variants (CNVs) are known to substantially increase susceptibility to schizophrenia. As a consequence of the low fecundity in people with ...schizophrenia and other neurodevelopmental phenotypes to which these CNVs contribute, CNVs with large effects on risk are likely to be rapidly removed from the population by natural selection. Accordingly, such CNVs must frequently occur as recurrent de novo mutations. In a sample of 662 schizophrenia proband-parent trios, we found that rare de novo CNV mutations were significantly more frequent in cases (5.1% all cases, 5.5% family history negative) compared with 2.2% among 2623 controls, confirming the involvement of de novo CNVs in the pathogenesis of schizophrenia. Eight de novo CNVs occurred at four known schizophrenia loci (3q29, 15q11.2, 15q13.3 and 16p11.2). De novo CNVs of known pathogenic significance in other genomic disorders were also observed, including deletion at the TAR (thrombocytopenia absent radius) region on 1q21.1 and duplication at the WBS (Williams-Beuren syndrome) region at 7q11.23. Multiple de novos spanned genes encoding members of the DLG (discs large) family of membrane-associated guanylate kinases (MAGUKs) that are components of the postsynaptic density (PSD). Two de novos also affected EHMT1, a histone methyl transferase known to directly regulate DLG family members. Using a systems biology approach and merging novel CNV and proteomics data sets, systematic analysis of synaptic protein complexes showed that, compared with control CNVs, case de novos were significantly enriched for the PSD proteome (P=1.72 × 10⁻⁶. This was largely explained by enrichment for members of the N-methyl-D-aspartate receptor (NMDAR) (P=4.24 × 10⁻⁶) and neuronal activity-regulated cytoskeleton-associated protein (ARC) (P=3.78 × 10⁻⁸) postsynaptic signalling complexes. In an analysis of 18 492 subjects (7907 cases and 10 585 controls), case CNVs were enriched for members of the NMDAR complex (P=0.0015) but not ARC (P=0.14). Our data indicate that defects in NMDAR postsynaptic signalling and, possibly, ARC complexes, which are known to be important in synaptic plasticity and cognition, play a significant role in the pathogenesis of schizophrenia.
Dynamic supply chain scheduling Ivanov, D.; Sokolov, B.
Journal of scheduling,
04/2012, Volume:
15, Issue:
2
Journal Article
Peer reviewed
Open access
Based on a combination of fundamental results of modern optimal program control theory and operations research, an original approach to supply chain scheduling is developed in order to answer the ...challenges of dynamics, uncertainty, and adaptivity. Both supply chain schedule generation and execution control are represented as an optimal program control problem in combination with mathematical programming and interpreted as a dynamic process of operations control within an adaptive framework. Hence, the problems and models of planning, scheduling, and adaptation can be consistently integrated on a unified mathematical axiomatic of modern control theory. In addition, operations control and flow control models are integrated and applicable for both discrete and continuous processes. The application of optimal control for supply chain scheduling becomes possible by formulating the scheduling model as a linear non-stationary finite-dimensional controlled differential system with the convex area of admissible control and a reconfigurable structure. For this model class, theorems of optimal control existence can be used regarding supply chain scheduling. The essential structural property of this model are the linear right parts of differential equations. This allows applying methods of discrete optimization for optimal control calculation. The calculation procedure is based on applying Pontryagin’s maximum principle and the resulting essential reduction of problem dimensionality that is under solution at each instant of time. The gained insights contribute to supply chain scheduling theory, providing advanced insights into dynamics of the whole supply chains (and not any dyadic relations in them) and transition from a partial “one-way” schedule optimization to the feedback loop-based dynamic and adaptive supply chain planning and scheduling.
The authors of our journal repeatedly expressed concern about the large number of accidents (electrical breakdowns) occurring at electrical, diagnostic, and cryogenic inputs into forcibly cooled ...superconducting magnets of fusion installations. However, the need for efficient measures for improving the reliability of the electrical insulation of these inputs, at least until last year, was ignored. In 2021, during the launch tests of Japanese-European tokamak JT-60SA, another accident occurred with an electrical breakdown at the electrical and diagnostic input into the tokamak, which, according to the project managers, would delay the launch of the tokamak by about 15 months.
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