706 research outputs found
Wavepacket Dynamics in Yang-Mills Theory
We discuss the results of numerical simulations of colliding wavepackets in
Yang--Mills theory. We investigate their behavior as a function of
amplitude and momentum distribution. We find regions in our parameter space in
which initial wave packets scatter into final configurations with dramatically
different momentum distributions. These results constitute new classical
trajectories with multiparticle boundary conditions. We explain their relevance
for the calculation of scattering amplitudes in the semiclassical
approximation. Finally, we give directions for future work.Comment: 11 pgs. text, 11 optional figs using PiCTeX and epsf, new version
contains improved discussion of scaling properties of results and one
additional figure
Protocol for fast scRNA-seq raw data processing using scKB and non-arbitrary quality control with COPILOT
We describe a protocol to perform fast and non-arbitrary quality control of single-cell RNA sequencing (scRNA-seq) raw data using scKB and COPILOT. scKB is a wrapper script of kallisto and bustools for accelerated alignment and transcript count matrix generation, which runs significantly faster than the popular tool Cell Ranger. COPILOT then offers non-arbitrary background noise removal by comparing distributions of low-quality and high-quality cells. Together, this protocol streamlines the processing workflow and provides an easy entry for new scRNA-seq users. For complete details on the use and execution of this protocol, please refer to Shahan etĀ al. (2022)
Synthesis, structural and physical properties of -FeSe
We report on synthesis, structural characterization, resistivity, magnetic
and thermal expansion measurements on the as yet unexplored -phase of
FeSe, here synthesized under ambient- (AP) and high-pressure (HP)
conditions. We show that in contrast to -FeSe, monophasic
superconducting -FeSe can be obtained in off-stoichiometric
samples with excess Fe atoms preferentially residing in the van der Waals gap
between the FeSe layers. The AP -FeSe sample studied here
( 8.5\,K) possesses an unprecedented residual resistivity ratio
RRR 16. Thermal expansion data reveal a small feature around
90\,K, which resembles the anomaly observed at the structural and
magnetic transitions for other Fe-based superconductors, suggesting that some
kind of "magnetic state" is formed also in FeSe. %indicative of a fluctuating
magnetic ordering. For HP samples (RRR 3), the disorder within the
FeSe layers is enhanced through the introduction of vacancies, the saturated
magnetic moment of Fe is reduced and only spurious superconductivity is
observed.Comment: 7 pages, 8 figures, published versio
WHO-ISG collaboration on assistive technologies for healthy ageing-in-place:A round table discussion
Assistive Technology (AT) is used at various points in the lifespan by those coping with either short-term or long-term impairments, which can involve living with chronic conditions and/or comorbidities. In the case of older adults, AT can support or compensate for the functional or cognitive declines that they are likely to face in later life. AT can be integrated as part of smart homes (see Figure 1 from van Dijken et al, 2006); and should be safe to use, effective, easy to access, affordable, and not seen as stigmatising. In addition, AT should support older adults to have a meaningful life while building self-esteem, and autonomy and promoting social participation and community engagement. For this roundtable discussion, we present and discuss a WHO-ISG collaborative project focused on Assistive Technology for Healthy Ageing. For this project, we consider applications and use AT not only from a medical standpoint but also situated within a social perspective in the context of Gerontechnology. Results and propositions according to the WHO-UNICEF global report on assistive technology were applied as a starting point for this project (WHO, 2022), prioritising the potential benefits to individuals, their communities, and society and with a focus on identifying potential barriers that may occur and how to mitigate them
Stationary distributions for diffusions with inert drift
Consider reflecting Brownian motion in a bounded domain in that acquires drift in proportion to the amount of local time spent on the boundary of the domain. We show that the stationary distribution for the joint law of the position of the reflecting Brownian motion and the value of the drift vector has a product form. Moreover, the first component is uniformly distributed on the domain, and the second component has a Gaussian distribution. We also consider more general reflecting diffusions with inert drift as well as processes where the drift is given in terms of the gradient of a potential
Physical properties of FeSeTe single crystals grown under different conditions
We report on structural, magnetic, conductivity, and thermodynamic studies of
FeSeTe single crystals grown by self-flux and Bridgman methods.
The samples were prepared from starting materials of different purity at
various temperatures and cooling rates. The lowest values of the susceptibility
in the normal state, the highest transition temperature of 14.5 K, and
the largest heat-capacity anomaly at were obtained for pure (oxygen-free)
samples. The critical current density of A/cm (at 2
K) achieved in pure samples is attributed to intrinsic inhomogeneity due to
disorder at the cation and anion sites. The impure samples show increased
up to A/cm due to additional pinning centers of
FeO. The upper critical field of kOe is estimated
from the resistivity study in magnetic fields parallel to the \emph{c}-axis.
The anisotropy of the upper critical field reaches a value at . Extremely low values of the residual Sommerfeld coefficient for pure
samples indicate a high volume fraction of the superconducting phase (up to
97%). The electronic contribution to the specific heat in the superconducting
state is well described within a single-band BCS model with a temperature
dependent gap K. A broad cusp-like anomaly in the electronic
specific heat of samples with suppressed bulk superconductivity is ascribed to
a splitting of the ground state of the interstitial Fe ions. This
contribution is fully suppressed in the ordered state in samples with bulk
superconductivity.Comment: 11 pages, 11 figures, 3 table
Forecasting movements of health-care stock prices based on different categories of news articles using multiple kernel learning
āThe market state changes when a new piece of information arrives. It affects decisions made by investors and is considered to be an important data source that can be used for financial forecasting. Recently information derived from news articles has become a part of financial predictive systems. The usage of news articles and their forecasting potential have been extensively researched.
However, so far no attempts have been made to utilise different categories of news articles simultaneously. This paper studies how the concurrent, and appropriately weighted, usage of news articles, having different degrees of relevance to the target stock, can improve the performance of financial forecasting and support the decision-making process of investors and traders. Stock price movements are predicted using the multiple kernel learning technique which integrates information extracted from multiple news categories while separate kernels are utilised to analyse each category. News articles are partitioned according to their relevance to the target stock, its sub industry, industry, group industry and sector. The experiments are run on stocks from the Health Care sector and show that increasing the number of relevant news categories used as data sources for financial forecasting improves the performance of the predictive system in comparison with approaches based on a lower number of categories
Competing Orders in Coupled Luttinger Liquids
We consider the problem of two coupled Luttinger liquids both at half filling
and at low doping levels, to investigate the problem of competing orders in
quasi-one-dimensional strongly correlated systems. We use bosonization and
renormalization group equations to investigate the phase diagrams, to determine
the allowed phases and to establish approximate boundaries among them. Because
of the chiral translation and reflection symmetry in the charge mode away from
half filling, orders of charge density wave (CDW) and spin-Peierls (SP)
diagonal current (DC) and -density wave (DDW) form two doublets and thus can
be at most quasi-long range ordered. At half-filling, umklapp terms break this
symmetry down to a discrete group and thus Ising-type ordered phases appear as
a result of spontaneous breaking of the residual symmetries. Quantum disordered
Haldane phases are also found, with finite amplitudes of pairing orders and
triplet counterparts of CDW, SP, DC and DDW. Relations with recent numerical
results and implications to similar problems in two dimensions are discussed.Comment: 16 pages, 5 figures, 4 tables. Revised manuscript; a misprint in Eq.
B3 has been corrected. The paper is already in print in PR
A single-cell Arabidopsis root atlas reveals developmental trajectories in wild-type and cell identity mutants
In all multicellular organisms, transcriptional networks orchestrate organ development. The Arabidopsis root, with its simple structure and indeterminate growth, is an ideal model for investigating the spatiotemporal transcriptional signatures underlying developmental trajectories. To map gene expression dynamics across root cell types and developmental time, we built a comprehensive, organ-scale atlas at single-cell resolution. In addition to estimating developmental progressions in pseudotime, we employed the mathematical concept of optimal transport to infer developmental trajectories and identify their underlying regulators. To demonstrate the utility of the atlas to interpret new datasets, we profiled mutants for two key transcriptional regulators at single-cell resolution, shortroot and scarecrow. We report transcriptomic and in vivo evidence for tissue trans-differentiation underlying a mixed cell identity phenotype in scarecrow. Our results support the atlas as a rich community resource for unraveling the transcriptional programs that specify and maintain cell identity to regulate spatiotemporal organ development
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