489 research outputs found
Cosmic ray anisotropies at high energies
The directional anisotropies of the energetic cosmic ray gas due to the relative motion between the observers frame and the one where the relativistic gas can be assumed isotropic is analyzed. The radiation fluxes formula in the former frame must follow as the Lorentz invariance of dp/E, where p, E are the 4-vector momentum-energy components; dp is the 3-volume element in the momentum space. The anisotropic flux shows in such a case an amplitude, in a rotating earth, smaller than the experimental measurements from say, EAS-arrays for primary particle energies larger than 1.E(14) eV. Further, it is shown that two consecutive Lorentz transformations among three inertial frames exhibit the violation of dp/E invariance between the first and the third systems of reference, due to the Wigner rotation. A discussion of this result in the context of the experimental anisotropic fluxes and its current interpretation is given
Statistical multi-moment bifurcations in random delay coupled swarms
We study the effects of discrete, randomly distributed time delays on the
dynamics of a coupled system of self-propelling particles. Bifurcation analysis
on a mean field approximation of the system reveals that the system possesses
patterns with certain universal characteristics that depend on distinguished
moments of the time delay distribution. Specifically, we show both
theoretically and numerically that although bifurcations of simple patterns,
such as translations, change stability only as a function of the first moment
of the time delay distribution, more complex patterns arising from Hopf
bifurcations depend on all of the moments
Tailoring magnetic anisotropy in epitaxial half metallic La0.7Sr0.3MnO3 thin films
We present a detailed study on the magnetic properties, including anisotropy,
reversal fields, and magnetization reversal processes, of well characterized
half-metallic epitaxial La0.7Sr0.3MnO3 (LSMO) thin films grown onto SrTiO3
(STO) substrates with three different surface orientations, i.e. (001), (110)
and (1-18). The latter shows step edges oriented parallel to the [110]
(in-plane) crystallographic direction. Room temperature high resolution
vectorial Kerr magnetometry measurements have been performed at different
applied magnetic field directions in the whole angular range. In general, the
magnetic properties of the LSMO films can be interpreted with just the uniaxial
term with the anisotropy axis given by the film morphology, whereas the
strength of this anisotropy depends on both structure and film thickness. In
particular, LSMO films grown on nominally flat (110)-oriented STO substrates
presents a well defined uniaxial anisotropy originated from the existence of
elongated in-plane [001]-oriented structures, whereas LSMO films grown on
nominally flat (001)-oriented STO substrates show a weak uniaxial magnetic
anisotropy with the easy axis direction aligned parallel to residual substrate
step edges. Elongated structures are also found for LSMO films grown on vicinal
STO(001) substrates. These films present a well-defined uniaxial magnetic
anisotropy with the easy axis lying along the step edges and its strength
increases with the LSMO thickness. It is remarkable that this step-induced
uniaxial anisotropy has been found for LSMO films up to 120 nm thickness. Our
results are promising for engineering novel half-metallic magnetic devices that
exploit tailored magnetic anisotropy.Comment: 10 pages, 10 figures, 1 tabl
A severe case of erythrodermic psoriasis associated with advanced nail and joint manifestations: a case report
<p>Abstract</p> <p>Introduction</p> <p>Erythrodermic psoriasis is a rare generalized clinical presentation of psoriasis in children and adults. Its systemic involvement and a diverse range of clinical findings in the joint and nails are commonly described. A high index of suspicion and an exhaustive differential diagnosis involving other causes of erythroderma should be initially considered.</p> <p>Case presentation</p> <p>We present the case of a 9-year-old native Hispanic girl with severe erythrodermic psoriasis associated with uncommon advanced nail and joint manifestations. Our patient showed an excellent response to methotrexate medication.</p> <p>Conclusion</p> <p>This case shows clinical features not commonly described or reported in severe cases of erythrodermic psoriasis, including severe and rare nail and arthritic findings in a pediatric scenario.</p
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Halving Food Loss and Waste in the EU by 2030: the major steps needed to accelerate progress
Unsustainable production and consumption of food constitutes one of the biggest environmental threats to our planet. Eliminating food loss and waste to the largest extent possible – at all stages from producer to final consumer – stands out as an urgent and indispensable step towards more sustainable food systems. The EU’s recent adoption of the Circular Economy Package, including the revision of its Waste Framework Directive in 2018 and a new Delegated Act on the measurement of food waste in 2019, opens a limited time period where Member States will have to integrate these policies into their national law. In 2020, the first EU-wide national measurement of food waste will be undertaken. This will be reported back to the EU mid2022 and will provide comparative baseline measures for all Member States. The publication of this baseline data in 2023 will provide the opportunity to consider the feasibility of establishing Union-wide food waste reduction targets to be met by 2025 and 2030. For this reason, 2020–2023 will provide crucial moments of opportunity for EU Member States’ food waste policy and EU-wide food waste reduction. Indeed, changes in the regulatory framework were necessary but need to be accompanied by further action to effectively accelerate food waste reductions. Through a rapid review of food waste literature and interviews with Member State representatives, this report identifies and provides case studies of the food waste reduction actions that have the largest evidence bases and largest potential for accelerating progress towards SDG target 12.3 (halving food waste by 2030 and reducing food losses), but which have been insufficiently applied in the EU until now: Food waste measurement; Valorisation; and Voluntary Agreements. Some of these actions are already partly developed in the EU (valorisation), while others have only recently been piloted across several Member States (voluntary agreements) or still need to be deployed coherently (food waste measurement). This report also highlights other interventions that show less evidence of their potential to date, but which are expected to hold high potential for effective food waste reduction: Changes to the Common Agricultural Policy; Stronger Regulation; and National Food Waste Strategies. Due to the interconnected nature of food waste, and of the EU and Member State policies, all food waste reduction areas proposed are interlinked and related. Together they offer a suite of actions that can be deployed over a range of time scales, from 12 months through to 5 years; and at a range of sizes, from individual companies or specific industry sectors, through to government-led deployment on a national scale. These actions will all benefit from close collaboration between the stakeholders, who can jointly deliver the urgently needed acceleration in food waste reduction
Stability of trions in strongly spin-polarized two-dimensional electron gases
Low-temperature magneto-photoluminescence studies of negatively charged
excitons (X- trions) are reported for n-type modulation-doped ZnSe/Zn(Cd,Mn)Se
quantum wells over a wide range of Fermi energy and spin-splitting. The
magnetic composition is chosen such that these magnetic two-dimensional
electron gases (2DEGs) are highly spin-polarized even at low magnetic fields,
throughout the entire range of electron densities studied (5e10 to 6.5e11
cm^-2). This spin polarization has a pronounced effect on the formation and
energy of X-, with the striking result that the trion ionization energy (the
energy separating X- from the neutral exciton) follows the temperature- and
magnetic field-tunable Fermi energy. The large Zeeman energy destabilizes X- at
the nu=1 quantum limit, beyond which a new PL peak appears and persists to 60
Tesla, suggesting the formation of spin-triplet charged excitons.Comment: 5 pages (RevTex), 4 embedded EPS figs. Submitted to PRB-R
Identification of rare-disease genes using blood transcriptome sequencing and large control cohorts.
It is estimated that 350 million individuals worldwide suffer from rare diseases, which are predominantly caused by mutation in a single gene1. The current molecular diagnostic rate is estimated at 50%, with whole-exome sequencing (WES) among the most successful approaches2-5. For patients in whom WES is uninformative, RNA sequencing (RNA-seq) has shown diagnostic utility in specific tissues and diseases6-8. This includes muscle biopsies from patients with undiagnosed rare muscle disorders6,9, and cultured fibroblasts from patients with mitochondrial disorders7. However, for many individuals, biopsies are not performed for clinical care, and tissues are difficult to access. We sought to assess the utility of RNA-seq from blood as a diagnostic tool for rare diseases of different pathophysiologies. We generated whole-blood RNA-seq from 94 individuals with undiagnosed rare diseases spanning 16 diverse disease categories. We developed a robust approach to compare data from these individuals with large sets of RNA-seq data for controls (n = 1,594 unrelated controls and n = 49 family members) and demonstrated the impacts of expression, splicing, gene and variant filtering strategies on disease gene identification. Across our cohort, we observed that RNA-seq yields a 7.5% diagnostic rate, and an additional 16.7% with improved candidate gene resolution
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