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Editorial.
Welcome to the third issue of our journal . We are delighted to feature in this issue two peer-reviewed papers looking in detail at some of the outcomes of the ring-fenced money used for researcher development in the UK under the guise of Roberts funding. In her paper looking at impact of the training provided by this funding on late stage doctoral student researchers, Walsh and colleagues draw our attention to detailed analysis of impact via a variety of evaluation approaches. She also alerts us to the question of whether such development programmes should run alongside the traditional apprenticeship style training of such students. The second paper by Heading and colleagues provides a detailed example of a development programme event in information management and provides further evidence for impact of such training.
Bai and Hudson move the focus to the research –teaching nexus and highlight the difficulty for TEFL staff in Chinese HEIs to develop a research strand in their careers. The importance in developing research capacity, providing support and mentoring to such staff is shown to be pivotal in their development.
Finally conceptions of research from a variety of viewpoints are analyzed by Pitcher. Pitcher considers how the PhD itself, alongwith how the knowledge and outcomes of PhD research are perceived. In a preliminary survey of students on these matters, Pitcher highlights the importance of alignment with these concepts between student and supervisor thus avoiding difficulties between apprentice and supervisor as the research progresses which might inhibit development
FLOWERING LOCUS C -dependent and -independent regulation of the circadian clock by the autonomous and vernalization pathways
Background
The circadian system drives pervasive biological rhythms in plants. Circadian clocks integrate endogenous timing information with environmental signals, in order to match rhythmic outputs to the local day/night cycle. Multiple signaling pathways affect the circadian system, in ways that are likely to be adaptively significant. Our previous studies of natural genetic variation in Arabidopsis thaliana accessions implicated FLOWERING LOCUS C (FLC) as a circadian-clock regulator. The MADS-box transcription factor FLC is best known as a regulator of flowering time. Its activity is regulated by many regulatory genes in the "autonomous" and vernalization-dependent flowering pathways. We tested whether these same pathways affect the circadian system.
Results
Genes in the autonomous flowering pathway, including FLC, were found to regulate circadian period in Arabidopsis. The mechanisms involved are similar, but not identical, to the control of flowering time. By mutant analyses, we demonstrate a graded effect of FLC expression upon circadian period. Related MADS-box genes had less effect on clock function. We also reveal an unexpected vernalization-dependent alteration of periodicity.
Conclusion
This study has aided in the understanding of FLC's role in the clock, as it reveals that the network affecting circadian timing is partially overlapping with the floral-regulatory network. We also show a link between vernalization and circadian period. This finding may be of ecological relevance for developmental programing in other plant species
Low Vision in Older Adults
Educational Objectives
1. Understand the epidemiology of visual impairments of older adults.
2. Understand the symptoms of functional loss secondary to visual impairments.
3. Understand the rehabilitative options available for those with vision loss.
4. Understand the multi-disciplinary approach in low vision rehabilitation.
5. Understand the impact of low vision rehabilitation services
ATXR5 and ATXR6 are H3K27 monomethyltransferases required for chromatin structure and gene silencing.
Constitutive heterochromatin in Arabidopsis thaliana is marked by repressive chromatin modifications, including DNA methylation, histone H3 dimethylation at Lys9 (H3K9me2) and monomethylation at Lys27 (H3K27me1). The enzymes catalyzing DNA methylation and H3K9me2 have been identified; alterations in these proteins lead to reactivation of silenced heterochromatic elements. The enzymes responsible for heterochromatic H3K27me1, in contrast, remain unknown. Here we show that the divergent SET-domain proteins ARABIDOPSIS TRITHORAX-RELATED PROTEIN 5 (ATXR5) and ATXR6 have H3K27 monomethyltransferase activity, and atxr5 atxr6 double mutants have reduced H3K27me1 in vivo and show partial heterochromatin decondensation. Mutations in atxr5 and atxr6 also lead to transcriptional activation of repressed heterochromatic elements. Notably, H3K9me2 and DNA methylation are unaffected in double mutants. These results indicate that ATXR5 and ATXR6 form a new class of H3K27 methyltransferases and that H3K27me1 represents a previously uncharacterized pathway required for transcriptional repression in Arabidopsis
Engineering Electromagnetic Properties of Periodic Nanostructures Using Electrostatic Resonances
Electromagnetic properties of periodic two-dimensional sub-wavelength
structures consisting of closely-packed inclusions of materials with negative
dielectric permittivity in a dielectric host with positive
can be engineered using the concept of multiple electrostatic
resonances. Fully electromagnetic solutions of Maxwell's equations reveal
multiple wave propagation bands, with the wavelengths much longer than the
nanostructure period. It is shown that some of these bands are described using
the quasi-static theory of the effective dielectric permittivity
, and are independent of the nanostructure period. Those bands
exhibit multiple cutoffs and resonances which are found to be related to each
other through a duality condition. An additional propagation band characterized
by a negative magnetic permeability develops when a magnetic moment is induced
in a given nano-particle by its neighbors. Imaging with sub-wavelength
resolution in that band is demonstrated
Pleiotropy of FRIGIDA enhances the potential for multivariate adaptation.
An evolutionary response to selection requires genetic variation; however, even if it exists, then the genetic details of the variation can constrain adaptation. In the simplest case, unlinked loci and uncorrelated phenotypes respond directly to multivariate selection and permit unrestricted paths to adaptive peaks. By contrast, 'antagonistic' pleiotropic loci may constrain adaptation by affecting variation of many traits and limiting the direction of trait correlations to vectors that are not favoured by selection. However, certain pleiotropic configurations may improve the conditions for adaptive evolution. Here, we present evidence that the Arabidopsis thaliana gene FRI (FRIGIDA) exhibits 'adaptive' pleiotropy, producing trait correlations along an axis that results in two adaptive strategies. Derived, low expression FRI alleles confer a 'drought escape' strategy owing to fast growth, low water use efficiency and early flowering. By contrast, a dehydration avoidance strategy is conferred by the ancestral phenotype of late flowering, slow growth and efficient water use during photosynthesis. The dehydration avoidant phenotype was recovered when genotypes with null FRI alleles were transformed with functional alleles. Our findings indicate that the well-documented effects of FRI on phenology result from differences in physiology, not only a simple developmental switch
A high-finesse Fabry-Perot cavity with a frequency-doubled green laser for precision Compton polarimetry at Jefferson Lab
A high-finesse Fabry-Perot cavity with a frequency-doubled continuous wave
green laser (532~nm) has been built and installed in Hall A of Jefferson Lab
for high precision Compton polarimetry. The infrared (1064~nm) beam from a
ytterbium-doped fiber amplifier seeded by a Nd:YAG nonplanar ring oscillator
laser is frequency doubled in a single-pass periodically poled MgO:LiNbO
crystal. The maximum achieved green power at 5 W IR pump power is 1.74 W with a
total conversion efficiency of 34.8\%. The green beam is injected into the
optical resonant cavity and enhanced up to 3.7~kW with a corresponding
enhancement of 3800. The polarization transfer function has been measured in
order to determine the intra-cavity circular laser polarization within a
measurement uncertainty of 0.7\%. The PREx experiment at Jefferson Lab used
this system for the first time and achieved 1.0\% precision in polarization
measurements of an electron beam with energy and current of 1.0~GeV and
50~A.Comment: 20 pages, 22 figures, revised version of arXiv:1601.00251v1,
submitted to NIM
One-dimensional lattice of oscillators coupled through power-law interactions: Continuum limit and dynamics of spatial Fourier modes
We study synchronization in a system of phase-only oscillators residing on
the sites of a one-dimensional periodic lattice. The oscillators interact with
a strength that decays as a power law of the separation along the lattice
length and is normalized by a size-dependent constant. The exponent of
the power law is taken in the range . The oscillator frequency
distribution is symmetric about its mean (taken to be zero), and is
non-increasing on . In the continuum limit, the local density of
oscillators evolves in time following the continuity equation that expresses
the conservation of the number of oscillators of each frequency under the
dynamics. This equation admits as a stationary solution the unsynchronized
state uniform both in phase and over the space of the lattice. We perform a
linear stability analysis of this state to show that when it is unstable,
different spatial Fourier modes of fluctuations have different stability
thresholds beyond which they grow exponentially in time with rates that depend
on the Fourier modes. However, numerical simulations show that at long times,
all the non-zero Fourier modes decay in time, while only the zero Fourier mode
(i.e., the "mean-field" mode) grows in time, thereby dominating the instability
process and driving the system to a synchronized state. Our theoretical
analysis is supported by extensive numerical simulations.Comment: 7 pages, 4 figures. v2: new simulation results added, close to the
published versio
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