488 research outputs found
Rebellion against Reason? A Study of Expressive Choice and Strikes
In this paper we challenge the conventional view that strikes are caused by asymmetric
information regarding rm profitability such that union members are uninformed. Instead,
we build an expressive model of strikes where the perception of unfairness provides the
expressive benefi t of voting for a strike. The model predicts that larger union size increases both wage offers and the incidence of strikes. Furthermore, while asymmetric information is still important in causing strikes, we find that it is the employer who is not fully informed about the level of emotionality within the union, thereby contributing to strike incidence.
An empirical test using UK data provides support for the predictions. In particular, union size has a positive effect on the incidence of strikes and other industrial actions even when asymmetric information regarding profitability is controlled for
Atomic diffraction from nanostructured optical potentials
We develop a versatile theoretical approach to the study of cold-atom
diffractive scattering from light-field gratings by combining calculations of
the optical near-field, generated by evanescent waves close to the surface of
periodic nanostructured arrays, together with advanced atom wavepacket
propagation on this optical potential.Comment: 8 figures, 10 pages, submitted to Phys. Rev.
Superradiance from an ultrathin film of three-level V-type atoms: Interplay between splitting, quantum coherence and local-field effects
We carry out a theoretical study of the collective spontaneous emission
(superradiance) from an ultrathin film comprised of three-level atoms with
-configuration of the operating transitions. As the thickness of the system
is small compared to the emission wavelength inside the film, the local-field
correction to the averaged Maxwell field is relevant. We show that the
interplay between the low-frequency quantum coherence within the subspace of
the upper doublet states and the local-field correction may drastically affect
the branching ratio of the operating transitions. This effect may be used for
controlling the emission process by varying the doublet splitting and the
amount of low-frequency coherence.Comment: 15 pages, 5 figure
Design of smart garments for sports and rehabilitation
Physical exercise has proved benefits for general health [1] and can reduce the number
of sports injuries to one third [2]. However, an athlete that has been injured during sports practice
may omit this out of fear of discrimination, and worsen the injury in the weight room, during
strength training [5]. Monitoring physiological status of an athlete or rehabilitation patients
during training may thus help the person to get an earlier intervention, preventing injuries from
getting worse. With this in mind, we propose a set of compression garments – shirt and leggings
– with textile sensors to continually monitor heart and muscle activity, breathing rate and
temperature. This paper reports the design of the garments and production of the shirt, which
comprised a 3-lead ECG system, sEMG (Surface Electromiography) electrodes and a breathing
sensor. The ECG (Electrocardiography) system was tested and presented some good results, in
particular for very even movements, but the system still needs to be improved, in order to get a
better signal, when it comes to movements with a considerable amplitude.This work is financed by Project “Deus ex Machina”, NORTE-01-0145-FEDER-000026, funded by CCDRN, through Sistema de Apoio à Investigação Cientifica e Tecnológica (Projetos Estruturados I&D&I) of Programa Operacional Regional do Norte, from Portugal 2020 and by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007136.info:eu-repo/semantics/publishedVersio
Melting of tantalum at high pressure determined by angle dispersive x-ray diffraction in a double-sided laser-heated diamond-anvil cell
The high pressure and high temperature phase diagram of Ta has been studied
in a laser-heated diamond-anvil cell (DAC) using x-ray diffraction measurements
up to 52 GPa and 3800 K. The melting was observed at nine different pressures,
being the melting temperature in good agreement with previous laser-heated DAC
experiments, but in contradiction with several theoretical calculations and
previous piston-cylinder apparatus experiments. A small slope for the melting
curve of Ta is estimated (dTm/dP = 24 K/GPa at 1 bar) and a possible
explanation for this behaviour is given. Finally, a P-V-T equation of states is
obtained, being the temperature dependence of the thermal expansion coefficient
and the bulk modulus estimated.Comment: 31 pages, 8 figures, to appear in J.Phys.:Cond.Matte
Refined high-content imaging-based phenotypic drug screening in zebrafish xenografts
Zebrafish xenotransplantation models are increasingly applied for phenotypic drug screening to identify small compounds for precision oncology. Larval zebrafish xenografts offer the opportunity to perform drug screens at high-throughput in a complex in vivo environment. However, the full potential of the larval zebrafish xenograft model has not yet been realized and several steps of the drug screening workflow still await automation to increase throughput. Here, we present a robust workflow for drug screening in zebrafish xenografts using high-content imaging. We established embedding methods for high-content imaging of xenografts in 96-well format over consecutive days. In addition, we provide strategies for automated imaging and analysis of zebrafish xenografts including automated tumor cell detection and tumor size analysis over time. We also compared commonly used injection sites and cell labeling dyes and show specific site requirements for tumor cells from different entities. We demonstrate that our setup allows us to investigate proliferation and response to small compounds in several zebrafish xenografts ranging from pediatric sarcomas and neuroblastoma to glioblastoma and leukemia. This fast and cost-efficient assay enables the quantification of anti-tumor efficacy of small compounds in large cohorts of a vertebrate model system in vivo. Our assay may aid in prioritizing compounds or compound combinations for further preclinical and clinical investigations
Establishment of Histone Modifications after Chromatin Assembly
Every cell has to duplicate its entire genome during S-phase of the cell cycle. After replication, the newly synthesized DNA is rapidly assembled into chromatin. The newly assembled chromatin ‘matures’ and adopts a variety of different conformations. This differential packaging of DNA plays an important role for the maintenance of gene expression patterns and has to be reliably copied in each cell division. Posttranslational histone modifications are prime candidates for the regulation of the chromatin structure. In order to understand the maintenance of chromatin structures, it is crucial to understand the replication of histone modification patterns. To study the kinetics of histone modifications in vivo, we have pulse-labeled synchronized cells with an isotopically labeled arginine (15N4) that is 4 Da heavier than the naturally occurring 14N4 isoform. As most of the histone synthesis is coupled with replication, the cells were arrested at the G1/S boundary, released into S-phase and simultaneously incubated in the medium containing heavy arginine, thus labeling all newly synthesized proteins. This method allows a comparison of modification patterns on parental versus newly deposited histones. Experiments using various pulse/chase times show that particular modifications have considerably different kinetics until they have acquired a modification pattern indistinguishable from the parental histones
Growth accounting in economic history:Findings, lessons and new directions
There is now a large volume of growth accounting estimates covering the long run experience of advanced countries. However, most of the studies in economic history are not based on state-of-the-art methods. There is a trade-off between maintaining international comparability and achieving the best results for individual countries. A one-size-fits-all approach will not always do justice to the variety of historical experiences since the conventional assumptions may sometimes be inappropriate. Nevertheless, growth-accounting studies have produced some eye-catching results which provide food for thought both for economic historians and for growth economists. These include (1) the finding that TFP growth was comparatively slow during the First Industrial Revolution, (2) Solow's famous conclusion that TFP growth accounted for 7/8ths of American labour-productivity growth was atypical, (3) the impact of new general-purpose technologies on growth typically takes a long time to materialize, ICT being the notable exception and (4) that capital-deepening was much more important relative to TFP growth in east Asian than in western European catch-up growth. Growth accounting is undoubtedly a valuable item in the cliometrician's toolkit. Nonetheless, we anticipate the introduction of more sophisticated methods and look forward to progress in understanding what explains marked differences in TFP performance
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