2,728 research outputs found

    Electrodynamics in an LTB scenario

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    In this article we analyze the electrodynamics in curved space-time in LTB metric. We calculate the most general scale factor in this inhomogeneous Universe. We also study the presence of electromagnetic field bubbles in the Universe.Comment: 9 pages, Accepted for publication in the EPJ

    Cosmic acceleration and f(R)f(R) theory: perturbed solution in a matter FLRW model

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    In the present paper we consider f(R)f(R) gravity theories in the metric approach and we derive the equations of motion, focusing also on the boundary conditions. In such a way we apply the general equations to a first order perturbation expansion of the Lagrangian. We present a model able to fit supernovae data without introducing dark energy.Comment: 10 pages, 1 figur

    IRAS asteroid families

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    The Infrared Astronomical Satellite (IRAS) sampled the entire asteroid population at wavelengths from 12 to 100 microns during its 1983 all sky survey. The IRAS Minor Planet Survey (IMPS) includes updated results for more recently numbered as well as other additional asteroids with reliable orbital elements. Albedos and diameters were derived from the observed thermal emission and assumed absolute visual magnitudes and then entered into the IMPS database at the Infrared Processing and Analysis Center (IPAC) for members of the Themis, Eos, Koronis and Maria asteroid families and compared with their visual colors. The IMPS results for the small (down to about 20 km) asteroids within these major families confirm trends previously noted for their larger members. Each of these dynamical families which are defined by their similar proper elements appears to have homogeneous physical properties

    Generation of two genomic-integration-free DMD iPSC lines with mutations affecting all dystrophin isoforms and potentially amenable to exon-skipping

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    Duchenne muscular dystrophy (DMD) is the most common paediatric muscular dystrophy and is caused by mutations in the DYSTROPHIN gene. We generated two induced pluripotent stem cell (iPSC) lines from DMD patients with nonsense mutations in exons 68 (UCLi011-A) or 70 (UCLi012-A) by transfecting reprogramming mRNAs. Both mutations affect expression of all dystrophin isoforms. iPSCs expressed pluripotency-associated markers, differentiated into cells of the three germ layers in vitro and had normal karyotypes. The selected mutations are potentially amenable to read-through therapies, exon-skipping and gene-editing. These new iPSCs are also relevant to study DYSTROPHIN role in tissues other than skeletal muscle

    The impact of main belt asteroids on infrared--submillimetre photometry and source counts

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    > Among the components of the infrared and submillimetre sky background, the closest layer is the thermal emission of dust particles and minor bodies in the Solar System. This contribution is especially important for current and future infrared and submillimetre space instruments --like those of Spitzer, Akari and Herschel -- and must be characterised by a reliable statistical model. > We describe the impact of the thermal emission of main belt asteroids on the 5...1000um photometry and source counts, for the current and future spaceborne and ground-based instruments, in general, as well as for specific dates and sky positions. > We used the statistical asteroid model (SAM) to calculate the positions of main belt asteroids down to a size of 1km, and calculated their infrared and submillimetre brightness using the standard thermal model. Fluctuation powers, confusion noise values and number counts were derived from the fluxes of individual asteroids. > We have constructed a large database of infrared and submillimetre fluxes for SAM asteroids with a temporal resolution of 5 days, covering the time span January 1, 2000 -- December 31, 2012. Asteroid fluctuation powers and number counts derived from this database can be obtained for a specific observation setup via our public web-interface. > Current space instruments working in the mid-infrared regime (Akari and Spitzer Space Telescopes) are affected by asteroid confusion noise in some specific areas of the sky, while the photometry of space infrared and submillimetre instruments in the near future (e.g. Herschel and Planck Space Observatories) will not be affected by asteroids. Faint main belt asteroids might also be responsible for most of the zodiacal emission fluctuations near the ecliptic.Comment: accepted for publication in Astronomy & Astrophysics; Additional material (appendices) and the related web-interface can be found at: "http://kisag.konkoly.hu/solarsystem/irsam.html

    Cellular dynamics of myogenic cell migration: molecular mechanisms and implications for skeletal muscle cell therapies

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    Directional cell migration is a critical process underlying morphogenesis and post‐natal tissue regeneration. During embryonic myogenesis, migration of skeletal myogenic progenitors is essential to generate the anlagen of limbs, diaphragm and tongue, whereas in post‐natal skeletal muscles, migration of muscle satellite (stem) cells towards regions of injury is necessary for repair and regeneration of muscle fibres. Additionally, safe and efficient migration of transplanted cells is critical in cell therapies, both allogeneic and autologous. Although administration of various myogenic cell types has been done intramuscularly or intravascularly, functional restoration has not been achieved yet in patients with degenerative diseases affecting multiple large muscle. One of the key reasons for this negative outcome is the limited migration of donor cells, which hinders the overall cell engraftment potential. Here, we review mechanisms of myogenic stem/progenitor cell migration during skeletal muscle development and post‐natal regeneration. Furthermore, strategies utilised to improve migratory capacity of myogenic cells are examined in order to identify potential treatments that may be applied to future transplantation protocols

    Wall proteins of Vitis vinifera pollen II. Influence of environment and rootstock on the electrophoretic pattern

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    Soluble wall proteins from Vitis vinifera pollen are genotypically determined and their expression, if not the extent of their expression, is independent from external factors. After we had previously observed that the time of sample collection does not influence their electrophoretic pattern, we demonstrate in the present work that this is true also for environment where the vine is growing and for the rootstock on which the scion is grafted

    A SIMPLE STOCHASTIC MODEL FOR THE SARS-COV-2 EPIDEMIC CURVE

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    An epidemic curve is a graphic depiction of the number of outbreak cases by date of illness onset, ordinarily constructed after the disease outbreak is over. However, a good estimate of the epidemic curve early in an outbreak would be invaluable to health care officials. On the other hand, from the end of February, the SARS-CoV-2 epidemic in Brazil seems to not following the Europe, or in particular, Italy or Spain. Even if less tests have been applied, there are less deaths occurring in Brazil than in both cited countries. However, due to the few applied tests, there is no certain planning on the real number of active cases. To estimate the number of future cases, epidemiologists make an educated guess as to how many people might become affected. We have proposed a simple fitting model using a simulated annealing technique, testing it with the South Korea data. We have tested and discussed the uncertainties of the model. We also have analyzed the trends in the confirmed cases using this model for the five most affected countries plus Brazil along several epidemic weeks
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