3,506 research outputs found
Concepts in Light Microscopy of Viruses
Viruses threaten humans, livestock, and plants, and are difficult to combat. Imaging of viruses by light microscopy is key to uncover the nature of known and emerging viruses in the quest for finding new ways to treat viral disease and deepening the understanding of virus–host interactions. Here, we provide an overview of recent technology for imaging cells and viruses by light microscopy, in particular fluorescence microscopy in static and live-cell modes. The review lays out guidelines for how novel fluorescent chemical probes and proteins can be used in light microscopy to illuminate cells, and how they can be used to study virus infections. We discuss advantages and opportunities of confocal and multi-photon microscopy, selective plane illumination microscopy, and super-resolution microscopy. We emphasize the prevalent concepts in image processing and data analyses, and provide an outlook into label-free digital holographic microscopy for virus research
Feasibility and first results of a group program to increase the frequency of cognitively stimulating leisure activities in people with mild cognitive impairment (AKTIVA–MCI)
AKTIVA-MCI is a program for patients with mild cognitive impairment (MCI) that aims to enhance participation in cognitively stimulating leisure activities. Participation in cognitively stimulating activities seems to be a potential strategy for people with MCI delaying cognitive decline for a while. In total, 35 MCI patients were enrolled in the pilot study of whom 29 completed the whole program (16 female, 71.1±7.5 years; Mini Mental Status Examination score: 28±2.2). Daily activity protocols were used to measure the frequency of participation in cognitively stimulating activities during the program (12 sessions). Additional standardized psychometric tests and questionnaires were used to assess cognition, mood, and subjective memory decline. Analyses of the daily activity protocols showed that during the intervention participants increased the frequency of several cognitively stimulating leisure activities. Comparison of pre-post data indicates no changes in cognitive status, mood, and subjective memory decline. These findings indicate that the program is suitable for patients with MCI
{\bf -Function Evaluation of Gap Probabilities in Orthogonal and Symplectic Matrix Ensembles}
It has recently been emphasized that all known exact evaluations of gap
probabilities for classical unitary matrix ensembles are in fact
-functions for certain Painlev\'e systems. We show that all exact
evaluations of gap probabilities for classical orthogonal matrix ensembles,
either known or derivable from the existing literature, are likewise
-functions for certain Painlev\'e systems. In the case of symplectic
matrix ensembles all exact evaluations, either known or derivable from the
existing literature, are identified as the mean of two -functions, both
of which correspond to Hamiltonians satisfying the same differential equation,
differing only in the boundary condition. Furthermore the product of these two
-functions gives the gap probability in the corresponding unitary
symmetry case, while one of those -functions is the gap probability in
the corresponding orthogonal symmetry case.Comment: AMS-Late
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Responding to Climate Change: The Economy and Economics - Part of the Problem and Solution
The Climate Change Starter’s Guide provides an introduction and overview for education planners and practitioners on the wide range of issues relating to climate change and climate change education, including causes, impacts, mitigation and adaptation strategies, as well as some broad political and economic principles.
The aim of this guide is to serve as a starting point for mainstreaming climate change education into school curricula. It has been created to enable education planners and practitioners to understand the issues at hand, to review and analyse their relevance to particular national and local contexts, and to facilitate the development of education policies, curricula, programmes and lesson plans.
The guide covers four major thematic areas:
1. the science of climate change, which explains the causes and observed changes;
2. the social and human aspects of climate change including gender, health, migration, poverty and ethics;
3. policy responses to climate change including measures for mitigation and adaptation; and
4. education approaches including education for sustainable development, disaster reduction and sustainable lifestyles.
A selection of key resources in the form of publication titles or websites for further reading is provided after each of the thematic sections
Random Matrix Theory and the Sixth Painlev\'e Equation
A feature of certain ensembles of random matrices is that the corresponding
measure is invariant under conjugation by unitary matrices. Study of such
ensembles realised by matrices with Gaussian entries leads to statistical
quantities related to the eigenspectrum, such as the distribution of the
largest eigenvalue, which can be expressed as multidimensional integrals or
equivalently as determinants. These distributions are well known to be
-functions for Painlev\'e systems, allowing for the former to be
characterised as the solution of certain nonlinear equations. We consider the
random matrix ensembles for which the nonlinear equation is the form
of \PVI. Known results are reviewed, as is their implication by way of series
expansions for the distributions. New results are given for the boundary
conditions in the neighbourhood of the fixed singularities at of
\PVI displayed by a generalisation of the generating function for the
distributions. The structure of these expansions is related to Jimbo's general
expansions for the -function of \PVI in the neighbourhood of its
fixed singularities, and this theory is itself put in its context of the linear
isomonodromy problem relating to \PVI.Comment: Dedicated to the centenary of the publication of the Painlev\'e VI
equation in the Comptes Rendus de l'Academie des Sciences de Paris by Richard
Fuchs in 190
Interacting Binaries with Eccentric Orbits. Secular Orbital Evolution Due To Conservative Mass Transfer
We investigate the secular evolution of the orbital semi-major axis and
eccentricity due to mass transfer in eccentric binaries, assuming conservation
of total system mass and orbital angular momentum. Assuming a delta function
mass transfer rate centered at periastron, we find rates of secular change of
the orbital semi-major axis and eccentricity which are linearly proportional to
the magnitude of the mass transfer rate at periastron. The rates can be
positive as well as negative, so that the semi-major axis and eccentricity can
increase as well as decrease in time. Adopting a delta-function mass-transfer
rate of 10^{-9} M_\sun {\rm yr}^{-1} at periastron yields orbital evolution
timescales ranging from a few Myr to a Hubble time or more, depending on the
binary mass ratio and orbital eccentricity. Comparison with orbital evolution
timescales due to dissipative tides furthermore shows that tides cannot, in all
cases, circularize the orbit rapidly enough to justify the often adopted
assumption of instantaneous circularization at the onset of mass transfer. The
formalism presented can be incorporated in binary evolution and population
synthesis codes to create a self-consistent treatment of mass transfer in
eccentric binaries.Comment: 16 pages, 8 figures, Accepted by The Astrophysical Journa
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