188 research outputs found
Mass dependent Evolution of Field Early-Type Galaxies Since z=1
We present the Fundamental Plane (FP) of field early-type galaxies at
0.5<z<1.0. Our project is a continuation of our efforts to understand the
formation and evolution of early-type galaxies in different environments. The
target galaxies were selected from the comprehensive and homogeneous data set
of the Gemini/HST Galaxy Cluster Project. The distant field early-type galaxies
follow a steeper FP relation compared to the local FP. The change in the slope
of the FP can be interpreted as a mass-dependent evolution. Similar results
have been found for cluster early-type galaxies in high redshift galaxy
clusters at 0.8<z<1. Therefore, the slope change of the FP appears to be
independent of the environment of the galaxies.Comment: 2 pages, 1 figure, to appear in the proceedings of the IAU Symposium
no. 262, "Stellar Populations - Planning for the Next Decade", eds. G. R.
Bruzual and S. Charlo
Spiders can be recognized by counting their legs
Spiders are arthropods that can be distinguished from their closest
relatives, the insects, by counting their legs. Spiders have 8, insects just 6.
Spider graphs are a very restricted class of graphs that naturally appear in
the context of cograph editing. The vertex set of a spider (or its complement)
is naturally partitioned into a clique (the body), an independent set (the
legs), and a rest (serving as the head). Here we show that spiders can be
recognized directly from their degree sequences through the number of their
legs (vertices with degree 1). Furthermore, we completely characterize the
degree sequences of spiders
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Closely related bird species demonstrate flexibility between beak morphology and underlying developmental programs
The astonishing variation in the shape and size of bird beaks reflects a wide range of dietary specializations that played an important role in avian diversification. Among Darwin's finches, ground finches (Geospiza spp.) have beaks that represent scaling variations of the same shape, which are generated by alterations in the signaling pathways that regulate growth of the two skeletal components of the beak: the prenasal cartilage (pnc) and the premaxillary bone (pmx). Whether this developmental mechanism is responsible for variation within groups of other closely related bird species, however, has remained unknown. Here, we report that the Caribbean bullfinches (Loxigilla spp.), which are closely related to Darwin's finches, have independently evolved beaks of a novel shape, different from Geospiza, but also varying from each other only in scaling. However, despite sharing the same beak shape, the signaling pathways and tissues patterning Loxigilla beaks differ among the three species. In Loxigilla noctis, as in Geospiza, the pnc develops first, shaped by Bmp4 and CaM signaling, followed by the development of the pmx, regulated by TGFβIIr, β-catenin, and Dkk3 signaling. In contrast, beak morphogenesis in Loxigilla violacea and Loxigilla portoricensis is generated almost exclusively by the pmx through a mechanism in which Ihh and Bmp4 synergize to promote expansion of bone tissue. Together, our results demonstrate high flexibility in the relationship between morphology and underlying developmental causes, where different developmental programs can generate identical shapes, and similar developmental programs can pattern different shapes.Organismic and Evolutionary Biolog
Functional phage display of leech-derived tryptase inhibitor (LDTI): construction of a library and selection of thrombin inhibitors
The recombinant phage antibody system pCANTAB 5E has been used to display functionally active leech-derived tryptase inhibitor (LDTI) on the tip of the filamentous M13 phage, A limited combinatorial library of 5.2 x 10(4) mutants was created with a synthetic LDTI gene, using a degenerated oligonucleotide and the pCANTAB 5E phagemid. the mutations were restricted to the P1-P4' positions of the reactive site. Fusion phages and appropriate host strains containing the phagemids were selected after binding to thrombin and DNA sequencing. the variants LDTI-2T (K8R, I9V, S10, K11W, P12A), LDTI-5T (K8R, I9V, S10, K11S, P12L) and LDTI-10T (K8R, I9L, S10, K11D, P12I) were produced with a Saccharomyces cerevisiae expression system. the new inhibitors, LDTI-2T and -5T, prolong the blood clotting time, inhibit thrombin (Ki 302 nM and 28 nM) and trypsin (K-i 6.4 nM and 2.1 nM) but not factor Xa, plasma kallikrein or neutrophil elastase, the variant LDTI-10T binds to thrombin but does not inhibit it, the relevant reactive site sequences of the thrombin inhibiting variants showed a strong preference for arginine in position P1 (K8R) and for valine in P1' (I9V), the data indicate further that LDTI-5T might be a model candidate for generation of active-site directed thrombin inhibitors and that LDTI in general may be useful to generate specific inhibitors suitable for a better understanding of enzyme-inhibitor interactions. (C) 1999 Federation of European Biochemical Societies.UNIFESP, Dept Bioquim, EPM, BR-04044020 São Paulo, BrazilUniv Munich, Klinikum Innenstadt, Chirurg Klin & Poliklin, Klin Chem & Klin Biochem Abt, D-8000 Munich, GermanyUNIFESP, Dept Med, Disciplina Hematol, EPM, BR-04044020 São Paulo, BrazilUNIFESP, Dept Bioquim, EPM, BR-04044020 São Paulo, BrazilUNIFESP, Dept Med, Disciplina Hematol, EPM, BR-04044020 São Paulo, BrazilWeb of Scienc
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High-precision 14C measurements of parenchyma-rich Hymenolobium petraeum tree species confirm bomb-peak atmospheric levels and reveal local fossil-fuel CO2 emissions in the Central Amazon
Ionized gas discs in elliptical and S0 galaxies at z < 1
We analyse the extended, ionized-gas emission of 24 early-type galaxies (ETGs) at 0 < z < 1 from the ESO Distant Cluster Survey (EDisCS). We discuss different possible sources of ionization and favour star formation as the main cause of the observed emission. 10 galaxies have disturbed gas kinematics, while 14 have rotating gas discs. In addition, 15 galaxies are in the field, while 9 are in the infall regions of clusters. This implies that, if the gas has an internal origin, this is likely stripped as the galaxies get closer to the cluster centre. If the gas instead comes from an external source, then our results suggest that this is more likely acquired outside the cluster environment, where galaxy–galaxy interactions more commonly take place. We analyse the Tully–Fisher relation of the ETGs with gas discs, and compare them to EDisCS spirals. Taking a matched range of redshifts, MB < −20, and excluding galaxies with large velocity uncertainties, we find that, at fixed rotational velocity, ETGs are 1.7 mag fainter in MB than spirals. At fixed stellar mass, we also find that ETGs have systematically lower specific star formation rates than spirals. This study constitutes an important step forward towards the understanding of the evolution of the complex ISM in ETGs by significantly extending the look-back-time baseline explored so far
Frontal and insular input to the dorsolateral temporal pole in primates: Implications for auditory memory
The temporal pole (TP) has been involved in multiple functions from emotional and
social behavior, semantic processing,memory, language in humans and epilepsy surgery,
to the fronto-temporal neurodegenerative disorder (semantic) dementia. However, the
role of the TP subdivisions is still unclear, in part due to the lack of quantitative data
about TP connectivity. This study focuses in the dorsolateral subdivision of the TP:
area 38DL. Area 38DL main input originates in the auditory processing areas of the
rostral superior temporal gyrus. Among other connections, area 38DL conveys this
auditory highly processed information to the entorhinal, rostral perirhinal, and posterior
parahippocampal cortices, presumably for storage in long-term memory (Muñoz-López
et al., 2015). However, the connections of the TP with cortical areas beyond the temporal
cortex suggest that this area is part of a wider network. With the aim to quantitatively
determine the topographical, laminar pattern and weighting of the lateral TP afferents
from the frontal and insular cortices, we placed a total of 11 tracer injections of the
fluorescent retrograde neuronal tracers Fast Blue and Diamidino Yellow at different levels
of the lateral TP in rhesus monkeys. The results showed that circa 50% of the total
cortical input to area 38DL originates in medial frontal areas 14, 25, 32, and 24 (25%);
orbitofrontal areas Pro and PAll (15%); and the agranular, parainsular and disgranular
insula (10%). This study sets the anatomical bases to better understand the function of
the dorsolateral division of the TP. More specifically, these results suggest that area 38DL
forms part of the wider limbic circuit that might contribute, among other functions, with
an auditory component to multimodal memory processing
Plasma extracellular vesicle tau and TDP-43 as diagnostic biomarkers in FTD and ALS
Minimally invasive biomarkers are urgently needed to detect molecular pathology in frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Here, we show that plasma extracellular vesicles (EVs) contain quantifiable amounts of TDP-43 and full-length tau, which allow the quantification of 3-repeat (3R) and 4-repeat (4R) tau isoforms. Plasma EV TDP-43 levels and EV 3R/4R tau ratios were determined in a cohort of 704 patients, including 37 genetically and 31 neuropathologically proven cases. Diagnostic groups comprised patients with TDP-43 proteinopathy ALS, 4R tauopathy progressive supranuclear palsy, behavior variant FTD (bvFTD) as a group with either tau or TDP-43 pathology, and healthy controls. EV tau ratios were low in progressive supranuclear palsy and high in bvFTD with tau pathology. EV TDP-43 levels were high in ALS and in bvFTD with TDP-43 pathology. Both markers discriminated between the diagnostic groups with area under the curve values >0.9, and between TDP-43 and tau pathology in bvFTD. Both markers strongly correlated with neurodegeneration, and clinical and neuropsychological markers of disease severity. Findings were replicated in an independent validation cohort of 292 patients including 34 genetically confirmed cases. Taken together, the combination of EV TDP-43 levels and EV 3R/4R tau ratios may aid the molecular diagnosis of FTD, FTD spectrum disorders and ALS, providing a potential biomarker to monitor disease progression and target engagement in clinical trials.</p
Integrated Heart - Coupling multiscale and multiphysics models for the simulation of the cardiac function
Mathematical modelling of the human heart and its function can expand our understanding of various cardiac
diseases, which remain the most common cause of death in the developed world. Like other physiological
systems, the heart can be understood as a complex multiscale system involving interacting phenomena at the
molecular, cellular, tissue, and organ levels. This article addresses the numerical modelling of many aspects
of heart function, including the interaction of the cardiac electrophysiology system with contractile muscle
tissue, the sub-cellular activation-contraction mechanisms, as well as the hemodynamics inside the heart
chambers. Resolution of each of these sub-systems requires separate mathematical analysis and specially
developed numerical algorithms, which we review in detail. By using specific sub-systems as examples, we
also look at systemic stability, and explain for example how physiological concepts such as microscopic force
generation in cardiac muscle cells, translate to coupled systems of differential equations, and how their stability
properties influence the choice of numerical coupling algorithms. Several numerical examples illustrate
three fundamental challenges of developing multiphysics and multiscale numerical models for simulating
heart function, namely: (i) the correct upscaling from single-cell models to the entire cardiac muscle, (ii) the
proper coupling of electrophysiology and tissue mechanics to simulate electromechanical feedback, and (iii)
the stable simulation of ventricular hemodynamics during rapid valve opening and closure
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