1,319 research outputs found
PR-10, defensin and cold dehydrin genes are among those over expressed in Oxytropis (Fabaceae) species adapted to the arctic
In many studied plants, typical responses to cold treatment include up-regulating the hydrophilic COR/LEA genes and down-regulating photosynthesis-related genes, carbohydrate metabolism, GDSL-motif lipase, hormone metabolism and oxidative regulation genes. However, next to nothing is known about gene expression in arctic plants, which are actually adapted to a harsh, cold environment. The molecular mechanisms behind the many specific adaptations of arctic plants, such as slow growth, well-developed root systems and short stature, are not well understood. In this study, we examine whole plantlet transcriptome differences between two arctic and two temperate Oxytropis (Fabaceae) species, grown under their respective controlled environmental conditions. Gene expression differences are analyzed using cDNA library subtraction followed by expressed sequence tags sequencing and annotation. Sequences from a total of nearly 2,000 clones cluster into 121 and 368 unique genes from the arctic and from the temperate plants, respectively. The predominant biological process for genes from the arctic-enriched library is “response to stimulus”. A concurrent overexpression of pathogenesis-related class 10 proteins (PR-10), plant defensin and cold dehydrin genes is a novel feature for species adapted to stressful growth environment. The temperate-enriched genes are involved in photosynthesis, translation and nucleosome assembly. Interestingly, both arctic and temperate-enriched libraries also contain genes involved in ribosome biogenesis and assembly, however of different types. Real-time reverse transcription PCR of cold dehydrin and two PR-10 genes, as well as the light harvesting complex b1 genes demonstrates that the gene expression is dependent on species and growth conditions
Electric Dipole Moments of Leptons in the Presence of Majorana Neutrinos
We calculate the two-loop diagrams that give a non-zero contribution to the
electric dipole moment d_l of a charged lepton l due to possible Majorana
masses of neutrinos. Using the example with one generation of the Standard
Model leptons and two heavy right-handed neutrinos, we demonstrate that the
non-vanishing result for d_l first appears in order O(m_l m_\nu^2 G_F^2), where
m_\nu is the mass of the light neutrino and the see-saw type relation is
imposed. This effect is beyond the reach of presently planned experiments.Comment: 13 page
Liberal use of platelet transfusions in the acute phase of trauma resuscitation: a systematic review
Regulation of gene expression in human tendinopathy
<p>Abstract</p> <p>Background</p> <p>Chronic tendon injuries, also known as tendinopathies, are common among professional and recreational athletes. These injuries result in a significant amount of morbidity and health care expenditure, yet little is known about the molecular mechanisms leading to tendinopathy.</p> <p>Methods</p> <p>We have used histological evaluation and molecular profiling to determine gene expression changes in 23 human patients undergoing surgical procedures for the treatment of chronic tendinopathy.</p> <p>Results</p> <p>Diseased tendons exhibit altered extracellular matrix, fiber disorientation, increased cellular content and vasculature, and the absence of inflammatory cells. Global gene expression profiling identified 983 transcripts with significantly different expression patterns in the diseased tendons. Global pathway analysis further suggested altered expression of extracellular matrix proteins and the lack of an appreciable inflammatory response.</p> <p>Conclusions</p> <p>Identification of the pathways and genes that are differentially regulated in tendinopathy samples will contribute to our understanding of the disease and the development of novel therapeutics.</p
Constraints on Low-Mass WIMP Interactions on 19F from PICASSO
Recent results from the PICASSO dark matter search experiment at SNOLAB are
reported. These results were obtained using a subset of 10 detectors with a
total target mass of 0.72 kg of 19F and an exposure of 114 kgd. The low
backgrounds in PICASSO allow recoil energy thresholds as low as 1.7 keV to be
obtained which results in an increased sensitivity to interactions from Weakly
Interacting Massive Particles (WIMPs) with masses below 10 GeV/c^2. No dark
matter signal was found. Best exclusion limits in the spin dependent sector
were obtained for WIMP masses of 20 GeV/c^2 with a cross section on protons of
sigma_p^SD = 0.032 pb (90% C.L.). In the spin independent sector close to the
low mass region of 7 GeV/c2 favoured by CoGeNT and DAMA/LIBRA, cross sections
larger than sigma_p^SI = 1.41x10^-4 pb (90% C.L.) are excluded.Comment: 23 pages, 7 figures, to be published in Phys. Lett.
Hamiltonian Dynamics and the Phase Transition of the XY Model
A Hamiltonian dynamics is defined for the XY model by adding a kinetic energy
term. Thermodynamical properties (total energy, magnetization, vorticity)
derived from microcanonical simulations of this model are found to be in
agreement with canonical Monte-Carlo results in the explored temperature
region. The behavior of the magnetization and the energy as functions of the
temperature are thoroughly investigated, taking into account finite size
effects. By representing the spin field as a superposition of random phased
waves, we derive a nonlinear dispersion relation whose solutions allow the
computation of thermodynamical quantities, which agree quantitatively with
those obtained in numerical experiments, up to temperatures close to the
transition. At low temperatures the propagation of phonons is the dominant
phenomenon, while above the phase transition the system splits into ordered
domains separated by interfaces populated by topological defects. In the high
temperature phase, spins rotate, and an analogy with an Ising-like system can
be established, leading to a theoretical prediction of the critical temperature
.Comment: 10 figures, Revte
Co-creation of information leaflets to meet the support needs of people living with Complex Regional Pain Syndrome (CRPS) through innovative use of wiki technology
Objective: People living with Complex Regional Pain Syndrome (CRPS) experience frustration with the lack of knowledge and understanding of CRPS as a pain condition. We report on our attempt to address this issue.
Method: People living with CRPS taking part in a larger study were invited to co-construct a CRPS wiki page that addressed the areas in which they had experienced the most difficulty. A blank wiki page was set up for participants to populate with issues they felt needed to be raised and addressed.
Results: Participants failed to engage with the wiki technology. We modified our procedure and completed an inductive analysis of a sister-forum which participants were using as part of the larger study. Six issues of importance were identified. We used the discussion forum threads to populate the themes. Due to a continued lack of engagement with the wiki technology, the team decided to create a suite of leaflets which were piloted with delegates at a CRPS patient conference.
Conclusions: Future work should be mindful of the extent to which patients are able and willing to share their experiences through such technology. Striking the balance between patient-endorsed and researcher-driven co-creation of such material is imperative
Quasi-long-range ordering in a finite-size 2D Heisenberg model
We analyse the low-temperature behaviour of the Heisenberg model on a
two-dimensional lattice of finite size. Presence of a residual magnetisation in
a finite-size system enables us to use the spin wave approximation, which is
known to give reliable results for the XY model at low temperatures T. For the
system considered, we find that the spin-spin correlation function decays as
1/r^eta(T) for large separations r bringing about presence of a
quasi-long-range ordering. We give analytic estimates for the exponent eta(T)
in different regimes and support our findings by Monte Carlo simulations of the
model on lattices of different sizes at different temperatures.Comment: 9 pages, 3 postscript figs, style files include
Temperature dependent fluctuations in the two-dimensional XY model
We present a detailed investigation of the probability density function (PDF)
of order parameter fluctuations in the finite two-dimensional XY (2dXY) model.
In the low temperature critical phase of this model, the PDF approaches a
universal non-Gaussian limit distribution in the limit T-->0. Our analysis
resolves the question of temperature dependence of the PDF in this regime, for
which conflicting results have been reported. We show analytically that a weak
temperature dependence results from the inclusion of multiple loop graphs in a
previously-derived graphical expansion. This is confirmed by numerical
simulations on two controlled approximations to the 2dXY model: the Harmonic
and ``Harmonic XY'' models. The Harmonic model has no
Kosterlitz-Thouless-Berezinskii (KTB) transition and the PDF becomes
progressively less skewed with increasing temperature until it closely
approximates a Gaussian function above T ~ 4\pi. Near to that temperature we
find some evidence of a phase transition, although our observations appear to
exclude a thermodynamic singularity.Comment: 15 pages, 5 figures and 1 tabl
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