732 research outputs found
COBRA: a new European research project for organic plant breeding
Development of organic plant breeding and seed production will have a valuable impact on organic plant production. Breeding of plant material adapted for organic agriculture is crucial in order to cope with stresses such as climate change, weeds and seed borne diseases. Conventional varieties may not meet the specific needs of organic agriculture. The use of plant material adapted to conditions of organic agriculture will have a positive effect on the productivity and sustainability of organic crop production
Outskirts of Distant Galaxies In Absorption
QSO absorption spectroscopy provides a sensitive probe of both the neutral
medium and diffuse ionized gas in the distant Universe. It extends 21cm maps of
gaseous structures around low-redshift galaxies both to lower gas column
densities and to higher redshifts. Combining galaxy surveys with
absorption-line observations of gas around galaxies enables comprehensive
studies of baryon cycles in galaxy outskirts over cosmic time. This Chapter
presents a review of the empirical understanding of the cosmic neutral gas
reservoir from studies of damped Lya absorbers (DLAs). It describes the
constraints on the star formation relation and chemical enrichment history in
the outskirts of distant galaxies from DLA studies. A brief discussion of
available constraints on the ionized circumgalactic gas from studies of lower
column density Lya absorbers and associated ionic absorption transitions is
presented at the end.Comment: 45 pages, 7 figures, invited review, Book chapter in "Outskirts of
Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and
Space Science Library, Springer, in pres
Extraction of arbitrarily shaped objects using stochastic multiple birth-and-death dynamics and active contours
We extend the marked point process models that have been used for object extraction from images to arbitrarily shaped objects, without greatly increasing the computational complexity of sampling and estimation. The approach can be viewed as an extension of the active contour methodology to an a priori unknown number of objects. Sampling and estimation are based on a stochastic birth-and-death process defined in a space of multiple, arbitrarily shaped objects, where the objects are defined by the image data and prior information. The performance of the approach is demonstrated via experimental results on synthetic and real data
Phase I/II trial of concurrent extracranial palliative radiation therapy with Dabrafenib and Trametinib in metastatic BRAF V600E/K mutation-positive cutaneous Melanoma
Background: Concurrent treatment with BRAF inhibitors and palliative radiation therapy (RT) could be associated with increased toxicity, especially skin toxicity. Current Eastern Cooperative Oncology Group (ECOG) consensus guideline recommend ceasing BRAF inhibitors during RT. There is a lack of data regarding concurrent RT with combined BRAF and MEK inhibitors. This single-arm phase I/II trial was designed to assess the safety and tolerability of palliative RT with concurrent Dabrafenib and Trametinib in patients with BRAF-mutant metastatic melanoma. Materials and methods: Patients received Dabrafenib and Trametinib before and during palliative RT to soft tissue, nodal or bony metastases. The RT dose was escalated stepwise during the study period. Toxicity data including clinical photographs of the irradiated area was collected for up to 12 months following completion of RT. Results: Between June 2016 to October 2019, ten patients were enrolled before the study was stopped early due to low accrual rate. Six patients were treated at level 1 (20 Gy in 5 fractions, any location) and 4 patients at level 2a (30 Gy in 10 fractions with no abdominal viscera exposed). All alive patients completed one year of post-RT follow-up. Of the 82 adverse events (AEs) documented, the majority (90%) were grade 1 and 2. Eight grade 3 events (10%) occurred in five patients, only one was treatment-related (grade 3 fever due to Dabrafenib and Trametinib). No patients experienced grade 3 or 4 RT related toxicities, including skin toxicities. One serious AE was documented in relation to a grade 3 fever due to Dabrafenib and Trametinib requiring hospitalisation. Conclusions: The lack of grade 3 and 4 RT-related toxicities in our study suggests that Dabrafenib and Trametinib may be continued concurrently during fractionated non-visceral palliative RT to extracranial sites
Magnetized cosmological perturbations
A large-scale cosmic magnetic field affects not only the growth of density
perturbations, but also rotational instabilities and anisotropic deformation in
the density distribution. We give a fully relativistic treatment of all these
effects, incorporating the magneto-curvature coupling that arises in a
relativistic approach. We show that this coupling produces a small enhancement
of the growing mode on superhorizon scales. The magnetic field generates new
nonadiabatic constant and decaying modes, as well as nonadiabatic corrections
to the standard growing and decaying modes. Magnetized isocurvature
perturbations are purely decaying on superhorizon scales. On subhorizon scales
before recombination, magnetized density perturbations propagate as
magneto-sonic waves, leading to a small decrease in the spacing of acoustic
peaks. Fluctuations in the field direction induce scale-dependent vorticity,
and generate precession in the rotational vector. On small scales, magnetized
density vortices propagate as Alfv\'{e}n waves during the radiation era. After
recombination, they decay slower than non-magnetized vortices. Magnetic
fluctuations are also an active source of anisotropic distortion in the density
distribution. We derive the evolution equations for this distortion, and find a
particular growing solution.Comment: Revised version, typos corrected, to appear in Phys. Rev.
Plane-symmetric inhomogeneous magnetized viscous fluid universe with a variable
The behavior of magnetic field in plane symmetric inhomogeneous cosmological
models for bulk viscous distribution is investigated. The coefficient of bulk
viscosity is assumed to be a power function of mass density . The values of cosmological constant for these models are
found to be small and positive which are supported by the results from recent
supernovae Ia observations. Some physical and geometric aspects of the models
are also discussed.Comment: 18 pages, LaTex, no figur
Assessment of the Socio-Economic Impact of Late Blight and State of the Art of Management in European Organic Potato Production Systems
In Europe, late blight, caused by Phytophthora infestans, is the most devastating disease affecting organic (and conventional) potato production. Under suitable environmental conditions the disease can spread rapidly and it can cause complete crop loss. The extent of damage due to late blight depends on several factors: in organic production systems these factors include climate, choice of variety, soil management and use of crop protection agents such as copper. Therefore, the extent of economic damage varies between European regions.
Council Regulation (EEC) No 2092/91, amended by Commission Regulation (EC) No 473/2002 of 15 March 2002 regulates the use of copper in organic agriculture. Copper has been the single most important control agent in organic late blight control. Therefore, the reduction or an eventual phasing out of copper use will have varying impacts in different regions.
This report presents the results of a detailed survey that has been conducted in 7 European countries in the year 2001. It is a subproject of the EU-funded project Blight-MOP (QLRT 31065). The survey investigates legislative, socio-economic and production parameters. The aim of this study was: (i) to obtain an inventory of the current organic potato production techniques, (ii) to assess the impact of a potential ban of copper on yields and viability of organic potato production and (iii) to identify alternative plant protection strategies that are used by organic farmers.
This report includes:
(i) statistics on yields, farm gate prices, and production techniques,
(ii) an analysis offarmer observations and experiences on the extent and impact of late blight epidemics,
(iii) an analysis of the farmer’s motivations, expectations and their assessment of the potential impact of a copper ban. Using multiple linear regression we identified production factors which appear to consistently contribute to production success
From thermal rectifiers to thermoelectric devices
We discuss thermal rectification and thermoelectric energy conversion from
the perspective of nonequilibrium statistical mechanics and dynamical systems
theory. After preliminary considerations on the dynamical foundations of the
phenomenological Fourier law in classical and quantum mechanics, we illustrate
ways to control the phononic heat flow and design thermal diodes. Finally, we
consider the coupled transport of heat and charge and discuss several general
mechanisms for optimizing the figure of merit of thermoelectric efficiency.Comment: 42 pages, 22 figures, review paper, to appear in the Springer Lecture
Notes in Physics volume "Thermal transport in low dimensions: from
statistical physics to nanoscale heat transfer" (S. Lepri ed.
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