152 research outputs found
KP line solitons and Tamari lattices
The KP-II equation possesses a class of line soliton solutions which can be
qualitatively described via a tropical approximation as a chain of rooted
binary trees, except at "critical" events where a transition to a different
rooted binary tree takes place. We prove that these correspond to maximal
chains in Tamari lattices (which are poset structures on associahedra). We
further derive results that allow to compute details of the evolution,
including the critical events. Moreover, we present some insights into the
structure of the more general line soliton solutions. All this yields a
characterization of possible evolutions of line soliton patterns on a shallow
fluid surface (provided that the KP-II approximation applies).Comment: 49 pages, 36 figures, second version: section 4 expande
One Year Clinical Outcomes of Renal Artery Stenting: The Results of ODORI Registry
The safety, efficacy and long term clinical benefits of renal artery revascularization by stenting are still a matter of debate. The aim of our study was to define the safety and efficacy of renal artery stenting with the Tsunami peripheral stent (Terumo Corporation, Tokyo, Japan). The ODORI was a prospective, multicentre registry which enrolled 251 consecutive patients, (276 renal arteries) in 36 centres across Europe. The primary endpoint was acute procedural success defined as <30% residual stenosis after stent placement. Secondary endpoints included major adverse events, blood pressure control, serum creatinine level, and target lesion revascularization (TLR) at 6 and 12 months. Patients were 70 ± 10 years old, 59% were male, 33% had diabetes, and 96% hypertension. The main indications for renal stent implantation were hypertension in 83% and renal salvage in 39%. Direct stent implantation was performed in 76% of the cases. Acute success rate was 100% with residual stenosis of 2.5 ± 5.4%. Systolic/diastolic blood pressure decreased from a mean of 171/89 at baseline to 142/78 mmHg at 6 months (p < 0.0001 vs. baseline), and 141/80 mmHg at 12 months (p < 0.0001 vs. baseline). Mean serum creatinine concentration did not change significantly in the total population. However, there was significant improvement in the highest tercile (from 283 μmol/l at baseline to 205 and 209 μmol/l at 6 and 12 months respectively). At 12-months, rates of restenosis and TLR were 6.6 and 0.8% respectively. The 12 month cumulative rate of all major clinical adverse events was 6.4% while the rate of device or procedure related events was 2.4%. In hypertensive patients with atherosclerotic renal artery stenosis Tsunami peripheral balloon-expandable stent provides a safe revascularization strategy, with a potential beneficial impact on hypertension control and renal function in the highest risk patients
Microstructure and mechanical effects of spark plasma sintering in alumina monolithic ceramics
The specific effects of spark plasma sintering (SPS) on the creep behavior, microstructure and mechanical properties of alumina monolithic ceramic were investigated. SPS introduces strains that concentrate at grain boundaries and inhibit crack growth, resulting in an improvement in the flexural strength and fracture toughness. However, creep blocks grain boundary movements and decreases the reliability of the material. These strains can be removed by a post-sintering thermal treatment, which plays an important role in the distribution of dislocations. Crown Copyright (c) 2012 Published by Elsevier Ltd. on behalf of Acta Materialia Inc. All rights reserved.The authors would like to acknowledge the help of the EU for the financial support received under the IP-NANOKER NMP3-CT-2005-515784. A.B. acknowledges the Spanish Ministry of Science and Innovation for her Juan de la Cierva Contract (JCI-2011-10498). The authors are grateful to the Central Support Service in Experimental Research (SCSIE), University of Valencia for providing the HR-TEM facility.Alvarez-Clemares, I.; Borrell Tomás, MA.; Agouram, S.; Torrecillas, R.; Fernandez, A. (2013). Microstructure and mechanical effects of spark plasma sintering in alumina monolithic ceramics. Scripta Materialia. 68(8):603-606. https://doi.org/10.1016/j.scriptamat.2012.12.016S60360668
Many non-equivalent realizations of the associahedron
Hohlweg and Lange (2007) and Santos (2004, unpublished) have found two
different ways of constructing exponential families of realizations of the
n-dimensional associahedron with normal vectors in {0,1,-1}^n, generalizing the
constructions of Loday (2004) and Chapoton-Fomin-Zelevinsky (2002). We classify
the associahedra obtained by these constructions modulo linear equivalence of
their normal fans and show, in particular, that the only realization that can
be obtained with both methods is the Chapoton-Fomin-Zelevinsky (2002)
associahedron.
For the Hohlweg-Lange associahedra our classification is a priori coarser
than the classification up to isometry of normal fans, by
Bergeron-Hohlweg-Lange-Thomas (2009). However, both yield the same classes. As
a consequence, we get that two Hohlweg-Lange associahedra have linearly
equivalent normal fans if and only if they are isometric.
The Santos construction, which produces an even larger family of
associahedra, appears here in print for the first time. Apart of describing it
in detail we relate it with the c-cluster complexes and the denominator fans in
cluster algebras of type A.
A third classical construction of the associahedron, as the secondary
polytope of a convex n-gon (Gelfand-Kapranov-Zelevinsky, 1990), is shown to
never produce a normal fan linearly equivalent to any of the other two
constructions.Comment: 30 pages, 13 figure
Sustained proliferation in cancer: mechanisms and novel therapeutic targets
Proliferation is an important part of cancer development and progression. This is manifest by altered expression and/or activity of cell cycle related proteins. Constitutive activation of many signal transduction pathways also stimulates cell growth. Early steps in tumor development are associated with a fibrogenic response and the development of a hypoxic environment which favors the survival and proliferation of cancer stem cells. Part of the survival strategy of cancer stem cells may manifested by alterations in cell metabolism. Once tumors appear, growth and metastasis may be supported by overproduction of appropriate hormones (in hormonally dependent cancers), by promoting angiogenesis, by undergoing epithelial to mesenchymal transition, by triggering autophagy, and by taking cues from surrounding stromal cells. A number of natural compounds (e.g., curcumin, resveratrol, indole-3-carbinol, brassinin, sulforaphane, epigallocatechin-3-gallate, genistein, ellagitannins, lycopene and quercetin) have been found to inhibit one or more pathways that contribute to proliferation (e.g., hypoxia inducible factor 1, nuclear factor kappa B, phosphoinositide 3 kinase/Akt, insulin-like growth factor receptor 1, Wnt, cell cycle associated proteins, as well as androgen and estrogen receptor signaling). These data, in combination with bioinformatics analyses, will be very important for identifying signaling pathways and molecular targets that may provide early diagnostic markers and/or critical targets for the development of new drugs or drug combinations that block tumor formation and progression
Tissue-Specific Features of the T Cell Repertoire After Allogeneic Hematopoietic Cell Transplantation in Human and Mouse
T cells are the central drivers of many inflammatory diseases, but the repertoire of tissue-resident T cells at sites of pathology in human organs remains poorly understood. We examined the site-specificity of T cell receptor (TCR) repertoires across tissues (5 to 18 tissues per patient) in prospectively collected autopsies of patients with and without graft-versus-host disease (GVHD), a potentially lethal tissue-targeting complication of allogeneic hematopoietic cell transplantation, and in mouse models of GVHD. Anatomic similarity between tissues was a key determinant of TCR repertoire composition within patients, independent of disease or transplant status. The T cells recovered from peripheral blood and spleens in patients and mice captured a limited portion of the TCR repertoire detected in tissues. Whereas few T cell clones were shared across patients, motif-based clustering revealed shared repertoire signatures across patients in a tissue-specific fashion. T cells at disease sites had a tissue-resident phenotype and were of donor origin based on single-cell chimerism analysis. These data demonstrate the complex composition of T cell populations that persist in human tissues at the end stage of an inflammatory disorder after lymphocyte-directed therapy. These findings also underscore the importance of studying T cell in tissues rather than blood for tissue-based pathologies and suggest the tissue-specific nature of both the endogenous and posttransplant T cell landscape
Beyond African orality: digital preservation of Mandinka ʿAjamī archives of Casamance
This article focuses on the digital preservation of African sources written in Mandinka ʿAjamī, i.e. the enriched form of the Arabic script used to write the Mandinka language for centuries. ʿAjamī writing has been utilized to document intellectual traditions, histories, belief systems, and cultures of non-Arab Muslims around the world. ʿAjamī texts have played critical roles in the spread of Islam in Africa and continue to be used for both religious and non-religious writings. However, African ʿAjamī texts such as those of the Mandinka people of Casamance in southern Senegal are not well known beyond local communities. ʿAjamī texts in Mandinka and other Mande languages are among the least documented. Only a few Mande ʿAjamī texts are available to scholars. Thanks to the British Library’s Endangered Archives Programme (EAP), Africa’s rich written heritage in ʿAjamī and other scripts previously unavailable to academics is being preserved and made universally accessible.EAP1042 - Endangered Archives Programme, British LibraryAccepted manuscrip
Multi-ancestry genome-wide association study of 21,000 cases and 95,000 controls identifies new risk loci for atopic dermatitis
Genetic association studies have identified 21 loci associated with atopic dermatitis risk predominantly in populations of European ancestry. To identify further susceptibility loci for this common, complex skin disease, we performed a meta-analysis of >15 million genetic variants in 21,399 cases and 95,464 controls from populations of European, African, Japanese and Latino ancestry, followed by replication in 32,059 cases and 228,628 controls from 18 studies. We identified ten new risk loci, bringing the total number of known atopic dermatitis risk loci to 31 (with new secondary signals at four of these loci). Notably, the new loci include candidate genes with roles in the regulation of innate host defenses and T cell function, underscoring the important contribution of (auto)immune mechanisms to atopic dermatitis pathogenesis
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