496 research outputs found
Cucumber mosaic virus infection transiently breaks dsRNA-induced transgenic immunity to Potato virus Y in tobacco
Post-transcriptional gene silencing (PTGS), an intrinsic plant defense mechanism, can be efficiently triggered by double stranded (ds)RNA-producing transgenes and can provide high level virus resistance by specific targeting of cognate viral RNA. The discovery of virus-encoded suppressors of PTGS led to concerns about the stability of such resistance.
Here, we show that Cucumber mosaic virus (CMV) is able to suppress dsRNA-induced PTGS and the associated Potato virus Y (PVY) immunity in tobacco. CMV suppression supported only a transient PVY accumulation and did not prevent recovery of the transgenic plants from PVY infection. CMV inoculation resulted in strongly increased transgene mRNA levels due to suppression of PTGS, but accumulation of PVY-specific small interfering (si)RNA was unaffected.
However, PVY accumulation in previously immune plants resulted in increased PVY siRNA levels and transgene mRNA was no longer detected, despite the presence of CMV. Transgene mRNA returned to high levels once PVY was no longer detected in CMVinfected plants. Recovered and chronically CMV-infected tissues were immune to further PVY infection
Stigma experienced by family members of people with intellectual and developmental disabilities: multidimensional construct
Background:
There is a lack of good-quality instruments measuring stigma experienced by family members of stigmatised people. //
Aims:
To develop a self-report measure of stigma among families of people with intellectual and developmental disabilities and examine associations between family stigma and other variables. //
Method:
The new Family Stigma Instrument (FAMSI) was tested with 407 family carers, 53% of whose offspring had an autism spectrum disorder in addition to intellectual disability. They also completed measures of subjective well-being, caregiver burden, self-esteem and social support. //
Results:
The FAMSI yielded a five-factor structure and had good reliability. Perceived family stigma, caregiver burden and subjective well-being were the strongest predictors of family stigma. //
Conclusions:
This instrument can advance our understanding of the impact of stigma on family members. It can also help us understand sociodemographic, psychosocial and contextual variables of both the carer and cared for person that may influence family members' experiences. //
Declaration of interest: None
Completeness of Wilson loop functionals on the moduli space of and -connections
The structure of the moduli spaces \M := \A/\G of (all, not just flat)
and connections on a n-manifold is analysed. For any
topology on the corresponding spaces \A of all connections which satisfies
the weak requirement of compatibility with the affine structure of \A, the
moduli space \M is shown to be non-Hausdorff. It is then shown that the
Wilson loop functionals --i.e., the traces of holonomies of connections around
closed loops-- are complete in the sense that they suffice to separate all
separable points of \M. The methods are general enough to allow the
underlying n-manifold to be topologically non-trivial and for connections to be
defined on non-trivial bundles. The results have implications for canonical
quantum general relativity in 4 and 3 dimensions.Comment: Plain TeX, 7 pages, SU-GP-93/4-
Laser photon merging in proton-laser collisions
The quantum electrodynamical vacuum polarization effects arising in the
collision of a high-energy proton beam and a strong, linearly polarized laser
field are investigated. The probability that laser photons merge into one
photon by interacting with the proton`s electromagnetic field is calculated
taking into account the laser field exactly. Asymptotics of the probability are
then derived according to different experimental setups suitable for detecting
perturbative and nonperturbative vacuum polarization effects. The
experimentally most feasible setup involves the use of a strong optical laser
field. It is shown that in this case measurements of the polarization of the
outgoing photon and and of its angular distribution provide promising tools to
detect these effects for the first time.Comment: 38 pages, 9 figure
Silica Vesicle Nanovaccine Formulations Stimulate Long-Term Immune Responses to the Bovine Viral Diarrhoea Virus E2 Protein
Bovine Viral Diarrhoea Virus (BVDV) is one of the most serious pathogen, which causes tremendous economic loss to the cattle industry worldwide, meriting the development of improved subunit vaccines. Structural glycoprotein E2 is reported to be a major immunogenic determinant of BVDV virion. We have developed a novel hollow silica vesicles (SV) based platform to administer BVDV-1 Escherichia coli-expressed optimised E2 (oE2) antigen as a nanovaccine formulation. The SV-140 vesicles (diameter 50 nm, wall thickness 6 nm, perforated by pores of entrance size 16 nm and total pore volume of 0.934 cm(3)g(-1)) have proven to be ideal candidates to load oE2 antigen and generate immune response. The current study for the first time demonstrates the ability of freeze-dried (FD) as well as non-FD oE2/SV140 nanovaccine formulation to induce long-term balanced antibody and cell mediated memory responses for at least 6 months with a shortened dosing regimen of two doses in small animal model. The in vivo ability of oE2 (100 mu g)/SV-140 (500 mu g) and FD oE2 (100 mu g)/SV-140 (500 mu g) to induce long-term immunity was compared to immunisation with oE2 (100 mu g) together with the conventional adjuvant Quil-A from the Quillaja saponira (10 mu g) in mice. The oE2/SV-140 as well as the FD oE2/SV-140 nanovaccine generated oE2-specific antibody and cell mediated responses for up to six months post the final second immunisation. Significantly, the cell-mediated responses were consistently high in mice immunised with oE2/SV-140 (1,500 SFU/million cells) at the six-month time point. Histopathology studies showed no morphological changes at the site of injection or in the different organs harvested from the mice immunised with 500 mu g SV-140 nanovaccine compared to the unimmunised control. The platform has the potential for developing single dose vaccines without the requirement of cold chain storage for veterinary and human applications
Guiding cities under increased droughts: The limits to sustainable urban futures
Climate change is likely to increase droughts. The vulnerability of cities to droughts is increasing worldwide. Policy responses from cities to droughts lack consideration of long-term climatic and socio-economic scenarios, and focus on short-term emergency actions that disregard sustainability in the connected regional and river basin systems. We aim to explore the dynamics of the water-energy-land nexus in urban systems suffering increased climate change-related droughts, and their implications for sustainability. We complement a case study with a literature review providing cross-regional insights, and detail pervasive knowledge, policy and ambition gaps in the interaction between cities and droughts. We show that water availability with low emissions, without compromising ecosystems and with low costs to society, poses a local-scale limit to sustainable urban growth, a new concept delineating the limits to growth in cities. We conclude that urban and river basin planners need to institutionalize transparency and cross-sectoral integration in multi-sector partnerships, to consider long-term land use planning together with water and energy, and to apply integrated climate services to cities. Our study reveals the importance of including land, water and energy in long-term urban planning, and to connect them with the county, region, river basin and global scales. © 2021 The Author(s)The authors would like to express their gratitude for limited contributions, comments and discussions that helped to improve the manuscript to Muhamad Bahri, Jörg Cortekar, Mirabela Marin, Serban Octavian Davidescu, Iñaki Torres Cobián, and to two anonymous reviewers that helped to substantially improve the manuscript. Valuable feedback obtained in two conference sessions co‑lead by some of the authors (at Adaptation Futures 2018 in Cape Town, and at the 4th European Climate Change Adaptation conference, in Lisbon in 2019) is acknowledged. The authors acknowledge financial support from the project CLISWELN funded by ERA4CS. ERA4CS is an ERA-NET initiated by JPI Climate, and CLISWELN is funded by BMBF (DE), UEFISCDI (RO), BMBWF and FFG (AT), and MINECO (ES), with co-funding from the European Union (Grant 690462 ). This paper and the content included in it do not represent the opinion of the European Union, and the European Union is not responsible for any use that might be made of its content. Marta OlazabalThe authors would like to express their gratitude for limited contributions, comments and discussions that helped to improve the manuscript to Muhamad Bahri, Jörg Cortekar, Mirabela Marin, Serban Octavian Davidescu, Iñaki Torres Cobián, and to two anonymous reviewers that helped to substantially improve the manuscript. Valuable feedback obtained in two conference sessions co‑lead by some of the authors (at Adaptation Futures 2018 in Cape Town, and at the 4th European Climate Change Adaptation conference, in Lisbon in 2019) is acknowledged. The authors acknowledge financial support from the project CLISWELN funded by ERA4CS. ERA4CS is an ERA-NET initiated by JPI Climate, and CLISWELN is funded by BMBF (DE), UEFISCDI (RO), BMBWF and FFG (AT), and MINECO (ES), with co-funding from the European Union (Grant 690462 ). This paper and the content included in it do not represent the opinion of the European Union, and the European Union is not responsible for any use that might be made of its content. Marta Olazaba
Dependent coordinates in path integral measure factorization
The transformation of the path integral measure under the reduction procedure
in the dynamical systems with a symmetry is considered. The investigation is
carried out in the case of the Wiener--type path integrals that are used for
description of the diffusion on a smooth compact Riemannian manifold with the
given free isometric action of the compact semisimple unimodular Lie group. The
transformation of the path integral, which factorizes the path integral
measure, is based on the application of the optimal nonlinear filtering
equation from the stochastic theory. The integral relation between the kernels
of the original and reduced semigroup are obtained.Comment: LaTeX2e, 28 page
Confinement in Covariant Gauges
We examine the weak coupling limit of Euclidean SU(n) gauge theory in
covariant gauges. Following an earlier suggestion, an equivariant
BRST-construction is used to define the continuum theory on a finite torus. The
equivariant gauge fixing introduces constant ghost fields as moduli of the
model. We study the parameter- and moduli- space perturbatively. For quark flavors, the moduli flow to a non-trivial fixed point in certain
critical covariant gauges and the one-loop effective potential indicates that
the global SU(n) color symmetry of the gauge fixed model is spontaneously
broken to . Ward identities and renormalization group arguments
imply that the longitudinal gauge boson propagator at long range is dominated
by Goldstone bosons in these critical covariant gauges. In the large
limit, we derive a nonlinear integral equation for the expectation value of
large Wilson loops assuming that the exchange of Goldstone bosons dominates the
interaction at long range in critical covariant gauges. We find numerically
that the expectation value of large circular Wilson loops decreases
exponentially with the enclosed area in the absence of dynamical fermions. The
gauge invariance of this mechanism for confinement in critical covariant gauges
is discussed.Comment: 45 pages, Latex, uses psfig.sty and epsfig.sty to include
postscript-figure
One-loop Beta Functions for the Orientable Non-commutative Gross-Neveu Model
We compute at the one-loop order the beta-functions for a renormalisable
non-commutative analog of the Gross Neveu model defined on the Moyal plane. The
calculation is performed within the so called x-space formalism. We find that
this non-commutative field theory exhibits asymptotic freedom for any number of
colors. The beta-function for the non-commutative counterpart of the Thirring
model is found to be non vanishing.Comment: 16 pages, 9 figure
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