Experimental Models of Duchenne Muscular Dystrophy: Relationship with Cardiovascular Disease

Almost every boy that has Duchenne Muscular Dystrophy (DMD) will develop cardiac problems. Whereas, it used to be respiratory problems that was the main cause of death in these DMD boys; with the advent of better respiratory care it is now the cardiac involvement that is becoming the most common cause of their death. Once the heart is affected, there is progressive deterioration in the function of the heart over time. The main problem is the death of the cardiomyocytes. The cause of the cardiomyocyte death is due to the loss of dystrophin, this makes the sarcolemma more susceptible to damage, and leads to a cascade of calcium influx, calcium activated proteases and ultimately the death of the cardiomyocyte. The dead cardiomyocytes are replaced by fibrotic tissue, which results in a dilated cardiomyopathy (DCM) developing, which begins in the base of the left ventricle and progresses to involve the entire left ventricle. The treatments used for the DMD cardiomyopathy are based on ones designed for other forms of cardiac weakness and include ACE-inhibitors and β-blockers. New therapies based around the pathophysiology in DMD are now being introduced. This review will look at the pathophysiology of the cardiac problems in DMD and how the various animal models that are available can be used to design new treatment options for DMD boys

Abelian symmetries in multi-Higgs-doublet models

N-Higgs doublet models (NHDM) are a popular framework to construct electroweak symmetry breaking mechanisms beyond the Standard model. Usually, one builds an NHDM scalar sector which is invariant under a certain symmetry group. Although several such groups have been used, no general analysis of symmetries possible in the NHDM scalar sector exists. Here, we make the first step towards this goal by classifying the elementary building blocks, namely the abelian symmetry groups, with a special emphasis on finite groups. We describe a strategy that identifies all abelian groups which are realizable as symmetry groups of the NHDM Higgs potential. We consider both the groups of Higgs-family transformations only and the groups which also contain generalized CP transformations. We illustrate this strategy with the examples of 3HDM and 4HDM and prove several statements for arbitrary N.Comment: 33 pages, 2 figures; v2: conjecture 3 is proved and becomes theorem 3, more explanations of the main strategy are added, matches the published versio

Mode selection and phase locking of sidelobe-emitting semiconductor laser arrays via reflection coupling from an external narrow-bandwidth grating

A phase locked array design, utilizing direct reflection feedback between adjacent cavities by an external grating, is analyzed and proposed. The narrow grating reflection bandwidth causes longitudinal mode selection, while the array geometry causes transverse wavenumber selection through the coupling strength. As a result, only one among the free running cavity eigenmodes can couple effectively into a phase locked collective eigenmode. The coupled array mode is experiencing the high reflectivity of the grating and surpasses the low gain of the free running modes, that experience only a much lower reflectivity from the cavity edge antireflective coating. These results suggest that in-phase locking and single mode operation can be achieved simultaneously through the use of an external narrow-bandwidth grating

Identifying Birds' Collision Risk with Wind Turbines Using a Multidimensional Utilization Distribution Method

Renewable energy plays a key role in reducing greenhouse gas emissions. However, the expansion of wind farms has raised concerns about risks for bird collisions. We tested different methods used to understand whether birds' flight occurs over wind turbines and found kernel density estimators outperform other methods. Previous studies using kernel utilization distribution (KUD) have considered only the 2 horizontal dimensions (2D). However, if altitude is ignored, an unrealistic depiction of the situation may result because birds move in 3 dimensions (3D). We quantified the 3D space use of the Griffon vulture (Gyps fulvus) in El Estrecho natural park in Tarifa (southern Spain, on the northern shore of the Strait of Gibraltar) during 2012-2013, and, for the first time, their risk of collision with wind turbines in an area in the south of Spain. The 2D KUD showed a substantial overlap of the birds' flight paths with the wind turbines in the study area, whereas the 3D kernel estimate did not show such overlap. Our aim was to develop a new approach using 3D kernel estimation to understand the space use of soaring birds; these are killed by collision with wind turbines more often than any other bird types in southern Spain. We determined the probability of bird collision with an obstacle within its range. Other potential application areas include airfields, plane flight paths, and tall buildings. (c) 2020 The Authors. Wildlife Society Bulletin published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.Peer reviewe

Model-Independent Semileptonic Form Factors Using Dispersion Relations

We present a method for parametrizing heavy meson semileptonic form factors using dispersion relations, and from it produce a two-parameter description of the B -> B elastic form factor. We use heavy quark symmetry to relate this function to B -> D* l nu form factors, and extract |V_cb|=0.0355^{+0.0029}_{-0.0025} from experimental data with a least squares fit. Our method eliminates model-dependent uncertainties inherent in choosing a parametrization for the extrapolation of the differential decay rate to threshold.Comment: uses lanlmac(harvmac) and epsf, 12 pages, 1 eps figure included (Talk by BG at the 6-th International Symposium on Heavy Flavour Physics, Pisa, Italy, 6--10 June, 1995

Clustered star formation toward Berkeley 87/ON2 - I. Multiwavelength census and the population overlap problem

Context. Disentangling line-of-sight alignments of young stellar populations is crucial for observational studies of star-forming complexes. This task is particularly problematic in a Cygnus-X subregion where several components, located at different distances, overlap: the Berkeley 87 young massive cluster, the poorly known [DB2001] Cl05 embedded cluster, and the ON2 star-forming complex, which in turn is composed of several H II regions. Aims. We provide a methodology for building an exhaustive census of young objects that can consistently treat large differences in extinction and distance. Methods. OMEGA2000 near-infrared observations of the Berkeley 87/ON2 field were merged with archival data from Gaia, Chandra, Spitzer, and Herschel and with cross-identifications from the literature. To address the incompleteness effects and selection biases that arise from the line-of-sight overlap, we adapted existing methods for extinction estimation and young object classification. We also defined the intrinsic reddening index, Rint, a new tool for separating intrinsically red sources from those whose infrared color excess is caused by extinction. Finally, we introduce a new method for finding young stellar objects based on Rint. Results. We find 571 objects whose classification is related to recent or ongoing star formation. Together with other point sources with individual estimates of distance or extinction, we compile a catalog of 3005 objects to be used for further membership work. A new distance for Berkeley 87, (1673 ± 17) pc, is estimated as a median of 13 spectroscopic members with accurate Gaia EDR3 parallaxes. Conclusions. The flexibility of our approach, especially regarding the Rint definition, allows overcoming photometric biases caused by large variations in extinction and distance in order to obtain homogeneous catalogs of young sources. The multiwavelength census that results from applying our methods to the Berkeley 87/ON2 field will serve as a basis for disentangling the overlapped populations.D.dF. acknowledges the UNAM-DGAPA postdoctoral grant, the Generalitat Valenciana APOSTD/220/228 fellowship, and the Spanish Government AYA2015-68012-C2-2-P project. D.dF. and M.G. have received financial support from Spanish Government project ESP2017-86582-C4-1-R. C.R.-Z. acknowledges support from CONACYT project CB2017-2018 A1-S-9754. C.R.-Z. and E.J.B. acknowledge support from Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica, UNAM-DGAPA, grants IN108117 and IN109217, respectively