276 research outputs found
Inhibition of Transport of a Bose-Einstein Condensate in a Random Potential
We observe the suppression of the 1D transport of an interacting elongated
Bose-Einstein condensate in a random potential with a standard deviation small
compared to the typical energy per atom, dominated by the interaction energy.
Numerical solutions of the Gross-Pitaevskii equation reproduce well our
observations. We propose a scenario for disorder-induced trapping of the
condensate in agreement with our observations.Comment: Proceedings of the 17th International Conference on Laser
Spectroscopy (ICOLS 05), Cairngorms National Park, Scotland, 19-24 June 200
Galaxyâgalaxy lensing in the outskirts of CLASH clusters: constraints on local shear and testing massâluminosity scaling relation
We present a selection of 24 candidate galaxyâgalaxy lensing (GGL) identified from Hubble images in the outskirts of the massive galaxy clusters from the Cluster Lensing And Supernova survey with Hubble (CLASH) . These GGLs provide insights into the mass distributions at larger scales than the strong-lensing region in the cluster cores. We built parametric mass models for three of these GGLs showing simple lensing configurations, in order to assess the properties of their lens and its environment. We show that the local shear estimated from the GGLs traces the gravitational potential of the clusters at a radial distance of 1â2 arcmin, allowing us to derive their velocity dispersion. We also find a good agreement between the strength of the shear measured at the GGL positions through strong-lensing modelling and the value derived independently from a weak-lensing analysis of the background sources. Overall, we show the advantages of using single GGL events in the outskirts of clusters to robustly constrain the local shear, even when only photometric redshift estimates are known for the source. We argue that the massâluminosity scaling relation of cluster members can be tested by modelling the GGLs found around them, and show that the mass parameters can vary up to âŒ30âperâcent between the cluster and GGL models assuming this scaling relation
Une nouvelle approche pour comprendre la robustesse de lâos et de la dentine chez les NĂ©andertaliens : lâĂ©tude de la covariation entre lâos cortical et la dentine
Des Ă©tudes ont mis en Ă©vidence une plus grande robustesse du squelette infra-crĂąnien et des volumes de dentine proportionnellement plus Ă©levĂ©s chez les NĂ©andertaliens que chez les humains modernes. Lâorigine de ces diffĂ©rences est encore mal comprise. Cependant, lâos cortical et la dentine sont sous lâinfluence de gĂšnes similaires, partagent la mĂȘme origine embryonnaire, ont la mĂȘme composition organique et sont sensibles Ă des facteurs systĂ©miques semblables. Nous testons donc ici lâhypothĂš..
Myeloid-Epithelial-Reproductive Receptor Tyrosine Kinase and Milk Fat Globule Epidermal Growth Factor 8 Coordinately Improve Remodeling After Myocardial Infarction via Local Delivery of Vascular Endothelial Growth Factor.
BACKGROUND: In infarcted heart, improper clearance of dying cells by activated neighboring phagocytes may precipitate the transition to heart failure. We analyzed the coordinated role of 2 major mediators of efferocytosis, the myeloid-epithelial-reproductive protein tyrosine kinase (Mertk) and the milk fat globule epidermal growth factor (Mfge8), in directing cardiac remodeling by skewing the inflammatory response after myocardial infarction. METHODS AND RESULTS: We generated double-deficient mice for Mertk and Mfge8 (Mertk(-/-)/Mfge8(-/-)) and challenged them with acute coronary ligature. Compared with wild-type, Mertk-deficient (Mertk(-/-)), or Mfge8-deficient (Mfge8(-/-)) animals, Mertk(-/-)/Mfge8(-/-) mice displayed greater alteration in cardiac function and remodeling. Mertk and Mfge8 were expressed mainly by cardiac Ly6C(High and Low) monocytes and macrophages. In parallel, Mertk(-/-)/Mfge8(-/-) bone marrow chimeras manifested increased accumulation of apoptotic cells, enhanced fibrotic area, and larger infarct size, as well as reduced angiogenesis. We found that the abrogation of efferocytosis affected neither the ability of circulating monocytes to infiltrate cardiac tissue nor the number of resident Ly6C(High) and Ly6C(How) monocytes/macrophages populating the infarcted milieu. In contrast, combined Mertk and Mfge8 deficiency in Ly6C(High)/Ly6C(Low) monocytes/macrophages either obtained from in vitro differentiation of bone marrow cells or isolated from infarcted hearts altered their capacity of efferocytosis and subsequently blunted vascular endothelial growth factor A (VEGFA) release. Using LysMCre(+)/VEGFA(fl/fl) mice, we further identified an important role for myeloid-derived VEGFA in improving cardiac function and angiogenesis. CONCLUSIONS: After myocardial infarction, Mertk- and Mfge8-expressing monocyte/macrophages synergistically engage the clearance of injured cardiomyocytes, favoring the secretion of VEGFA to locally repair the dysfunctional heart
Spinocerebellar ataxia 27B: episodic symptoms and acetazolamide response in 34 patients
Ashton C et al report a retrospective multi-centre cohort of 34 patients from Canada, France, Austria and Australia with spinocerebellar ataxia 27B, describing the common feature of episodic ataxia and other episodic features, as well as the inefficacy of acetazolamide in these patients
Precision modeling of JWST's first cluster lens SMACSJ0723.3-7327
Exploiting the fundamentally achromatic nature of gravitational lensing, we
present a lens model for the massive galaxy cluster SMACSJ0723.3-7323 (SMACS
J0723, z=0.388) that significantly improves upon earlier work. Building on
strong-lensing constraints identified in prior Hubble Space Telescope (HST)
observations, the mass model utilizes 21 multiple-image systems, 16 of which
were newly discovered in Early Release Observation (ERO) data from the James
Webb Space Telescope (JWST). The resulting lens model maps the cluster mass
distribution to an RMS spatial precision of 1.08'' and is publicly available at
https://www.dropbox.com/sh/3iatmz5k4hafzqf/AAAh0JvLgpBVoLp6qsxYZkFGa?dl=0 .
Consistent with previous analyses, our study shows SMACSJ0723.3-7323 to be well
described by a single large-scale component centered on the location of the
brightest cluster galaxy, however JWST data point to the need for two
additional diffuse components west of the cluster, which in turn accounts for
all the currently identified multiply imaged systems. A comparison of the
galaxy distribution, the mass distribution, and gas distribution in the core of
SMACS0723 based on HST, JWST, and Chandra data reveals a fairly concentrated
regular elliptical profile along with tell-tale signs of recent merger
activity, possibly proceeding aligned closely to our line of sight. The
exquisite sensitivity of JWST's NIRCAM reveals in spectacular fashion both the
extended intra-cluster-light distribution and numerous star-forming clumps in
magnified background galaxies. The high-precision lens model derived here for
SMACSJ0723-7323 demonstrates impressively the power of combining HST and JWST
data for unprecedented studies of structure formation and evolution in the
distant Universe.Comment: Updated to match the version submitted to ApJ - analysis, results and
conclusions are unchanged. Link to the lensing outputs:
https://www.dropbox.com/sh/3iatmz5k4hafzqf/AAAh0JvLgpBVoLp6qsxYZkFGa?dl=
Evaluation of age, sex, and ancestry-related variation in cortical bone and dentine volumes in modern humans, and a preliminary assessment of cortical bone-dentine covariation in later Homo.
Cortical bone and dentine share similarities in their embryological origin, development, and genetic background. Few analyses have combined the study of cortical bone and dentine to quantify their covariation relative to endogenous and exogenous factors. However, knowing how these tissues relate in individuals is of great importance to decipher the factors acting on their evolution, and ultimately to understand the mechanisms responsible for the different patterns of tissue proportions shown in hominins. The aims of this study are to examine age-, sex-, and ancestry-related variation in cortical bone and dentine volumes, and to preliminary assess the possible covariation between these tissues in modern humans and in five composite Neandertals. The modern analytical sample includes 12 immature individuals from France and 49 adults from France and South Africa. Three-dimensional tissue proportions were assessed from microtomographic records of radii and permanent maxillary canines. Results suggest ontogenic differences and a strong sexual dimorphism in cortical bone and dentine developments. The developmental pattern of dentine also seems to vary according to individual's ancestry. We measure a stronger covariation signal between cortical bone and dentine volumes than with any other dental tissue. A more complex covariation pattern is shown when splitting the modern sample by age, sex, and ancestry, as no signal is found in some subsamples while others show a covariation between cortical bone and either crown or radicular dentine. Finally, no difference in cortical bone volume is noticed between the modern young adults and the five young adult composite Neandertals from Marine Isotopic Stages (MIS) 5 and 3. Greater dentine Cortical bone and dentine (co)variation volumes are measured in the MIS 5 chimeric Neandertals whereas a strong interpopulation variation in dentine thickness is noticed in the MIS 3 chimeric Neandertals. Further research on the cortical bonedentine covariation will increase understanding of the impact of endogenous and exogenous factors on the development of the mineralized tissues
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