3,960 research outputs found

    Dermal fin rays and scales derive from mesoderm, not neural crest

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    SummaryNeural crest cells disperse throughout the embryonic head to generate diverse cell types of two classes: non-ectomesenchymal (including melanocytes, peripheral neurons and glia) and ectomesenchymal (skeletogenic, odontogenic, cartilaginous and connective tissue cell fates). In contrast to cranial neural crest, trunk neural crest of amniotes generates only non-ectomesenchymal cell types. Anamniote trunk neural crest, however, has been assumed to generate derivatives of both classes, including osteoblasts of dermal skeletal elements, which includes scales and fin rays. Through genetic lineage tracing in zebrafish, we present the first test of this assumption and find that trunk neural crest does not generate fin osteoblasts; rather, these derive from a late emerging population of paraxial mesoderm. Similarly we show that the mineralising cells of the scales are mesodermally derived, with no contribution from neural crest. Our data suggest that trunk/tail exoskeletal structures evolved through deployment of mesodermally derived mesenchyme, rather than neural crest

    Temporal and spatial analyses on seismo-electric anomalies associated with the 27 February 2010 M = 8.8 Chile earthquake observed by DEMETER satellite

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    International audienceThis paper studies seismo-electromagnetic anomalies observed by the French satellite DEMETER (Detection of ElectroMagnetic Emissions Transmitted from Earthquake Regions) during the 27 February 2010 M = 8.8 Chile earthquake. The nighttime electron density (N e), electron temperature (T e), ion density (N i), ion temperature (T i) and whistler counts (C w) are investigated. A statistical analysis of the box-and-whisker method is applied to see if data of two or more groups under study are significantly different. A cross-examination of temporal variations before and after shows that N e and N i (C w) increases (decreases) appear 10–20 days before the earthquake. A comparison of data over the epicenter and those over its reference area can be employed to discriminate the earthquake-related anomalies from global effects. Results prove that anomalous enhancements of N e , N i , and T i occur specifically around the epicenter area. The intersection of the temporal and spatial results confirms that N e and N i are useful and sensitive detecting anomalous related to the 2010 M = 8.8 Chile earthquake

    A proposed integrated approach for the preclinical evaluation of phage therapy in Pseudomonas infections

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    Bacteriophage therapy is currently resurging as a potential complement/alternative to antibiotic treatment. However, preclinical evaluation lacks streamlined approaches. We here focus on preclinical approaches which have been implemented to assess bacteriophage efficacy against Pseudomonas biofilms and infections. Laser interferometry and profilometry were applied to measure biofilm matrix permeability and surface geometry changes, respectively. These biophysical approaches were combined with an advanced Airway Surface Liquid infection model, which mimics in vitro the normal and CF lung environments, and an in vivo Galleria larvae model. These assays have been implemented to analyze KTN4 (279,593 bp dsDNA genome), a type-IV pili dependent, giant phage resembling phiKZ. Upon contact, KTN4 immediately disrupts the P. aeruginosa PAO1 biofilm and reduces pyocyanin and siderophore production. The gentamicin exclusion assay on NuLi-1 and CuFi-1 cell lines revealed the decrease of extracellular bacterial load between 4 and 7 logs and successfully prevents wild-type Pseudomonas internalization into CF epithelial cells. These properties and the significant rescue of Galleria larvae indicate that giant KTN4 phage is a suitable candidate for in vivo phage therapy evaluation for lung infection applications

    The prognosis of allocentric and egocentric neglect : evidence from clinical scans

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    We contrasted the neuroanatomical substrates of sub-acute and chronic visuospatial deficits associated with different aspects of unilateral neglect using computed tomography scans acquired as part of routine clinical diagnosis. Voxel-wise statistical analyses were conducted on a group of 160 stroke patients scanned at a sub-acute stage. Lesion-deficit relationships were assessed across the whole brain, separately for grey and white matter. We assessed lesions that were associated with behavioural performance (i) at a sub-acute stage (within 3 months of the stroke) and (ii) at a chronic stage (after 9 months post stroke). Allocentric and egocentric neglect symptoms at the sub-acute stage were associated with lesions to dissociated regions within the frontal lobe, amongst other regions. However the frontal lesions were not associated with neglect at the chronic stage. On the other hand, lesions in the angular gyrus were associated with persistent allocentric neglect. In contrast, lesions within the superior temporal gyrus extending into the supramarginal gyrus, as well as lesions within the basal ganglia and insula, were associated with persistent egocentric neglect. Damage within the temporo-parietal junction was associated with both types of neglect at the sub-acute stage and 9 months later. Furthermore, white matter disconnections resulting from damage along the superior longitudinal fasciculus were associated with both types of neglect and critically related to both sub-acute and chronic deficits. Finally, there was a significant difference in the lesion volume between patients who recovered from neglect and patients with chronic deficits. The findings presented provide evidence that (i) the lesion location and lesion size can be used to successfully predict the outcome of neglect based on clinical CT scans, (ii) lesion location alone can serve as a critical predictor for persistent neglect symptoms, (iii) wide spread lesions are associated with neglect symptoms at the sub-acute stage but only some of these are critical for predicting whether neglect will become a chronic disorder and (iv) the severity of behavioural symptoms can be a useful predictor of recovery in the absence of neuroimaging findings on clinical scans. We discuss the implications for understanding the symptoms of the neglect syndrome, the recovery of function and the use of clinical scans to predict outcome

    The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: tomographic BAO analysis of DR12 combined sample in configuration space

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    We perform a tomographic baryon acoustic oscillations analysis using the two-point galaxy correlation function measured from the combined sample of BOSS DR12, which covers the redshift range of 0.2<z<0.750.2<z<0.75. Splitting the sample into multiple overlapping redshift slices to extract the redshift information of galaxy clustering, we obtain a measurement of DA(z)/rdD_A(z)/r_d and H(z)rdH(z)r_d at nine effective redshifts with the full covariance matrix calibrated using MultiDark-Patchy mock catalogues. Using the reconstructed galaxy catalogues, we obtain the precision of 1.3%2.2%1.3\%-2.2\% for DA(z)/rdD_A(z)/r_d and 2.1%6.0%2.1\%-6.0\% for H(z)rdH(z)r_d. To quantify the gain from the tomographic information, we compare the constraints on the cosmological parameters using our 9-bin BAO measurements, the consensus 3-bin BAO and RSD measurements at three effective redshifts in \citet{Alam2016}, and the non-tomographic (1-bin) BAO measurement at a single effective redshift. Comparing the 9-bin with 1-bin constraint result, it can improve the dark energy Figure of Merit by a factor of 1.24 for the Chevallier-Polarski-Linder parametrisation for equation of state parameter wDEw_{\rm DE}. The errors of w0w_0 and waw_a from 9-bin constraints are slightly improved when compared to the 3-bin constraint result.Comment: 14 pages, 21 figures, 7 Tables. Submitted to MNRA

    The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: single-probe measurements from CMASS anisotropic galaxy clustering

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    With the largest spectroscopic galaxy survey volume drawn from the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), we can extract cosmological constraints from the measurements of redshift and geometric distortions at quasi-linear scales (e.g. above 50 h1h^{-1}Mpc). We analyze the broad-range shape of the monopole and quadrupole correlation functions of the BOSS Data Release 12 (DR12) CMASS galaxy sample, at the effective redshift z=0.59z=0.59, to obtain constraints on the Hubble expansion rate H(z)H(z), the angular-diameter distance DA(z)D_A(z), the normalized growth rate f(z)σ8(z)f(z)\sigma_8(z), and the physical matter density Ωmh2\Omega_mh^2. We obtain robust measurements by including a polynomial as the model for the systematic errors, and find it works very well against the systematic effects, e.g., ones induced by stars and seeing. We provide accurate measurements {DA(0.59)rs,fid/rs\{D_A(0.59)r_{s,fid}/r_s Mpc\rm Mpc, H(0.59)rs/rs,fidH(0.59)r_s/r_{s,fid} kms1Mpc1km s^{-1} Mpc^{-1}, f(0.59)σ8(0.59)f(0.59)\sigma_8(0.59), Ωmh2}\Omega_m h^2\} = {1427±26\{1427\pm26, 97.3±3.397.3\pm3.3, 0.488±0.0600.488 \pm 0.060, 0.135±0.016}0.135\pm0.016\}, where rsr_s is the comoving sound horizon at the drag epoch and rs,fid=147.66r_{s,fid}=147.66 Mpc is the sound scale of the fiducial cosmology used in this study. The parameters which are not well constrained by our galaxy clustering analysis are marginalized over with wide flat priors. Since no priors from other data sets, e.g., cosmic microwave background (CMB), are adopted and no dark energy models are assumed, our results from BOSS CMASS galaxy clustering alone may be combined with other data sets, i.e., CMB, SNe, lensing or other galaxy clustering data to constrain the parameters of a given cosmological model. The uncertainty on the dark energy equation of state parameter, ww, from CMB+CMASS is about 8 per cent. The uncertainty on the curvature fraction, Ωk\Omega_k, is 0.3 per cent. We do not find deviation from flat Λ\LambdaCDM.Comment: 15 pages, 11 figures. The latest version matches and the accepted version by MNRAS. A bug in the first version has been identified and fixed in the new version. We have redone the analysis with newest data (BOSS DR12

    Effect of chronic octreotide treatment on intestinal absorption in patients with acromegaly

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    The adverse gastrointestinal effects of octreotide, a synthetic analog of somatostatin, have not been fully elucidated. Low-dose octreotide frequently causes adverse gastrointestinal symptoms in normal individuals. We investigated the adverse gastrointestinal effects of high-dose octreotide, which is required for the normalization of growth hormone hypersecretion in some patients with acromegaly. Patients with acromegaly ( N =8) were treated with octreotide, 450 μg/day, then 1500 μg/day for two months at each dosage. Carbohydrate absorption was assessed using the d -xylose test, and fat absorption using fecal fat excretion and serum carotene concentrations, at baseline, at each dosage of octreotide, and after one month of washout. Ultrasonography was used to monitor for cholelithiasis. Growth hormone and insulin-like growth factor-I concentrations were significantly suppressed at both dosages. Adverse gastrointestinal symptoms were mild and transient. d -Xylose absorption remained normal at each dosage and after one month of washout. Fecal fat excretion increased from 7±2 to 12±2 g/24 hr ( P <0.05) after the higher dosage and resumed baseline levels after the washout. Mean fasting serum carotene levels remained normal, and carotene loading test (15,000 units three times a day for three days) was unreliable in identifying patients with high fecal fat. No new cholelithiasis was detected by ultrasonography. One of two patients with preexisting cholelithiasis developed biliary colic several days after the treatment period. Although steatorrhea was common, small intestinal absorptive capacity was otherwise unchanged by four months of high-dose octreotide treatment, which significantly suppressed growth hormone secretion in acromegalic patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44417/1/10620_2005_Article_BF01307549.pd

    Exact Multifractality for Disordered N-Flavour Dirac Fermions in Two Dimensions

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    We present a nonperturbative calculation of all multifractal scaling exponents at strong disorder for critical wavefunctions of Dirac fermions interacting with a non-Abelian random vector potential in two dimensions. The results, valid for an arbitrary number of fermionic flavours, are obtained by deriving from Conformal Field Theory an effective Gaussian model for the wavefunction amplitudes and mapping to the thermodynamics of a single particle in a random potential. Our spectrum confirms that the wavefunctions remain delocalized in the presence of strong disorder.Comment: 4 pages, no figue

    Credibility and adjustment: gold standards versus currency boards

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    It is often maintained that currency boards (CBs) and gold standards (GSs) are alike in that they are stringent monetary rules, the two basic features of which are high credibility of monetary authorities and the existence of automatic adjustment (non discretionary) mechanism. This article includes a comparative analysis of these two types of regimes both from the perspective of the sources and mechanisms of generating confidence and credibility, and the elements of operation of the automatic adjustment mechanism. Confidence under the GS is endogenously driven, whereas it is exogenously determined under the CB. CB is a much more asymmetric regime than GS (the adjustment is much to the detriment of peripheral countries) although asymmetry is a typical feature of any monetary regime. The lack of credibility is typical for peripheral countries and cannot be overcome completely even by “hard” monetary regimes.http://deepblue.lib.umich.edu/bitstream/2027.42/40078/3/wp692.pd

    Heterosubtype Neutralizing Responses to Influenza A (H5N1) Viruses Are Mediated by Antibodies to Virus Haemagglutinin

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    Background: It is increasingly clear that influenza A infection induces cross-subtype neutralizing antibodies that may potentially confer protection against zoonotic infections. It is unclear whether this is mediated by antibodies to the neuraminidase (NA) or haemagglutinin (HA). We use pseudoviral particles (H5pp) coated with H5 haemagglutinin but not N1 neuraminidase to address this question. In this study, we investigate whether cross-neutralizing antibodies in persons unexposed to H5N1 is reactive to the H5 haemagglutinin. Methodology/Principal Findings: We measured H5-neutralization antibody titers pre- and post-vaccination using the H5N1 micro-neutralization test (MN) and H5pp tests in subjects given seasonal vaccines and in selected sera from European elderly volunteers in a H5N1 vaccine trial who had detectable pre-vaccination H5N1 MN antibody titers. We found detectable (titer ≥20) H5N1 neutralizing antibodies in a minority of pre-seasonal vaccine sera and evidence of a serological response to H5N1 in others after seasonal influenza vaccination. There was excellent correlation in the antibody titers between the H5N1 MN and H5pp tests. Similar correlations were found between MN and H5pp in the pre-vaccine sera from the cohort of H5N1 vaccine trial recipients. Conclusions/Significance: Heterosubtype neutralizing antibody to H5N1 in healthy volunteers unexposed to H5N1 is mediated by cross-reaction to the H5 haemagglutinin. Copyright: © 2009 Garcia et al.published_or_final_versio
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