803 research outputs found
Greece’s Three-Act Tragedy:A Simple Model of Grexit vs. Staying Afloat inside the Single Currency Area
Against the backdrop of the Greek three-act tragedy, we present a theoretical framework for studying Greece’s recent debt and currency crisis. The model is built on two essential blocks: first, erratic macroeconomic policymaking in Greece is described using a stochastic regimeswitching model; second, the euro area governments’ responses to uncertain macroeconomic policies in Greece are considered. The model’s mechanism and assumptions allow either for a Grexit from the euro area or, conversely, the avoidance of Greece’s default against its creditors. The model also offers useful guidance to understand key drivers of the long-winded negotiations between the Syiza government and the euro area governments
Experimental evidence of three-dimensional acoustic propagation caused by nonlinear internal waves
Author Posting. © Acoustical Society of America, 2005. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 118 (2005): 723-734, doi:10.1121/1.1942428.The 1995 SWARM experiment collected high quality environmental and acoustic data. One goal was to investigate nonlinear internal wave effects on acoustic signals. This study continues an investigation of broadband airgun data from the two southwest propagation tracks. One notable feature of the experiment is that a packet of nonlinear internal waves crossed these tracks at two different incidence angles. Observed variations for the lower angle track were modeled using two-dimensional parabolic equation calculations in a previous study. The higher incidence angle is close to critical for total internal reflection, suggesting that acoustic horizontal refraction occurs as nonlinear internal waves traverse this track. Three-dimensional adiabatic mode parabolic equation calculations reproduce principal features of observed acoustic intensity variations. The correspondence between data and simulation results provides strong evidence of the actual occurrence of horizontal refraction due to nonlinear internal waves.This work was supported by an ONR Ocean Acoustics Graduate Traineeship Award and by ONR grants to Rensselaer, the University of Delaware, and the Woods Hole Oceanographic Institution
On Effective Superpotentials and Compactification to Three Dimensions
We study four dimensional N=2 SO/SP supersymmetric gauge theory on R^3\times
S^1 deformed by a tree level superpotential. We will show that the exact
superpotential can be obtained by making use of the Lax matrix of the
corresponding integrable model which is the periodic Toda lattice. The
connection between vacua of SO(2N) and SO(2kN-2k+2) can also be seen in this
framework. Similar analysis can also be applied for SO(2N+1) and SP(2N).Comment: 18 pages, latex file, v2: typos corrected, refs adde
Unraveling the antifungal activity of a South American rattlesnake toxin crotamine
Crotamine is a highly basic peptide from the venom of Crotalus durissus terrificus rattlesnake. Its common gene ancestry and structural similarity with the beta-defensins, mainly due to an identical disulfide bond pattern, stimulated us to assess the antimicrobial properties of native, recombinant, and chemically synthesized crotamine. Antimicrobial activities against standard strains and clinical isolates were analyzed by the colorimetric microdilution method showing a weak antibacterial activity against both Gram-positive and Gram-negative bacteria [MIC (Minimum Inhibitory Concentration) of 50->200 mu g/mL], with the exception of Micrococcus luteus [MIC ranging from 1 to 2 mu g/mL]. No detectable activity was observed for the filamentous fungus Aspergillus fumigatus and Trichophyton rubrum at concentrations up to 125 mu g/mL. However, a pronounced antifungal activity against Candida spp., Trichosporon spp., and Cryptococcus neoformans [12.5-50.0 mu g/mL] was observed. Chemically produced synthetic crotamine in general displayed MIC values similar to those observed for native crotamine, whereas recombinant crotamine was overridingly more potent in most assays. On the other hand, derived short linear peptides were not very effective apart from a few exceptions. Pronounced ultrastructure alteration in Candida albicans elicited by crotamine was observed by electron microscopy analyses. the peculiar specificity for highly proliferating cells was confirmed here showing potential low cytotoxic effect of crotamine against nontumoral mammal cell lines (HEK293, PC12, and primary culture astrocyte cells) compared to tumoral B16F10 cells, and no hemolytic activity was observed. Taken together these results suggest that, at low concentration, crotamine is a potentially valuable anti-yeast or candicidal agent, with low harmful effects on normal mammal cells, justifying further studies on its mechanisms of action aiming medical and industrial applications. (C) 2012 Elsevier Masson SAS. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)University of Maryland Baltimore County Designated Research Initiative FundUniversidade Federal de São Paulo UNIFESP, Dept Farmacol, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Med, BR-04044020 São Paulo, BrazilUniv São Paulo, Dept Bioquim & Imunol, BR-14049 Ribeirao Preto, BrazilUniv Maryland, Sch Med, Inst Human Virol, Baltimore, MD 21201 USAUniv Maryland, Dept Biochem & Mol Biol, Baltimore, MD 21201 USAUniversidade Federal de São Paulo UNIFESP, Dept Bioquim, BR-04044020 São Paulo, BrazilInst Butantan, Lab Bioquim & Biofis, BR-05503900 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Ginecol, BR-04044020 São Paulo, BrazilCBA, Lab Bioquim & Biol Mol, Manaus, Amazonas, BrazilUniv Maryland Baltimore Cty, Dept Chem & Biochem, Baltimore, MD 21250 USAInst Butantan, Ctr Toxinol Aplicada CAT CEPID, BR-05503900 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Farmacol, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Med, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Bioquim, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Ginecol, BR-04044020 São Paulo, BrazilWeb of Scienc
Plastin 3 is upregulated in iPSC-derived motoneurons from asymptomatic SMN1-deleted individuals
Spinal muscular atrophy (SMA) is a devastating motoneuron (MN) disorder caused by homozygous loss of SMN1. Rarely, SMN1-deleted individuals are fully asymptomatic despite carrying identical SMN2 copies as their SMA III-affected siblings suggesting protection by genetic modifiers other than SMN2. High plastin 3 (PLS3) expression has previously been found in lymphoblastoid cells but not in fibroblasts of asymptomatic compared to symptomatic siblings. To find out whether PLS3 is also upregulated in MNs of asymptomatic individuals and thus a convincing SMA protective modifier, we generated induced pluripotent stem cells (iPSCs) from fibroblasts of three asymptomatic and three SMA III-affected siblings from two families and compared these to iPSCs from a SMA I patient and control individuals. MNs were differentiated from iPSC-derived small molecule neural precursor cells (smNPCs). All four genotype classes showed similar capacity to differentiate into MNs at day 8. However, SMA I-derived MN survival was significantly decreased while SMA III- and asymptomatic-derived MN survival was moderately reduced compared to controls at day 27. SMN expression levels and concomitant gem
numbers broadly matched SMN2 copy number distribution; SMA I presented the lowest levels, whereas SMA III and asymptomatic showed similar levels. In contrast, PLS3 was significantly upregulated in mixed MN cultures from asymptomatic individuals pinpointing a tissue-specific regulation. Evidence for strong PLS3 accumulation in shaft and rim of growth cones in MN cultures from asymptomatic individuals implies an important role in neuromuscular synapse formation and maintenance. These findings provide strong evidence that PLS3 is a genuine SMA protective modifier
On the exactness of the cavity method for Weighted b-Matchings on Arbitrary Graphs and its Relation to Linear Programs
We consider the general problem of finding the minimum weight b-matching on
arbitrary graphs. We prove that, whenever the linear programming relaxation of
the problem has no fractional solutions, then the cavity or belief propagation
equations converge to the correct solution both for synchronous and
asynchronous updating
Branes in Time-Dependent Backgrounds and AdS/CFT Correspondence
We study supergravity solutions of Dp-branes in the time-dependent orbifold
background. We show that worldvolume theories decouple from the bulk gravity
for p less than six. Along AdS/CFT correspondence, these solutions could
provide the gravity description of noncommutative field theory with
time-dependent noncommutative parameter. Type II NS5-brane (M5-brane) in the
presence of RR n-form for n=0,..., 4 (C field) in this time-dependent
background have also been studied.Comment: 15 pages, latex file, v2: typos corrected, ref added, v3: references
added, minor change
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Multi-ancestry study of blood lipid levels identifies four loci interacting with physical activity.
Many genetic loci affect circulating lipid levels, but it remains unknown whether lifestyle factors, such as physical activity, modify these genetic effects. To identify lipid loci interacting with physical activity, we performed genome-wide analyses of circulating HDL cholesterol, LDL cholesterol, and triglyceride levels in up to 120,979 individuals of European, African, Asian, Hispanic, and Brazilian ancestry, with follow-up of suggestive associations in an additional 131,012 individuals. We find four loci, in/near CLASP1, LHX1, SNTA1, and CNTNAP2, that are associated with circulating lipid levels through interaction with physical activity; higher levels of physical activity enhance the HDL cholesterol-increasing effects of the CLASP1, LHX1, and SNTA1 loci and attenuate the LDL cholesterol-increasing effect of the CNTNAP2 locus. The CLASP1, LHX1, and SNTA1 regions harbor genes linked to muscle function and lipid metabolism. Our results elucidate the role of physical activity interactions in the genetic contribution to blood lipid levels
Anti-cancer effects and mechanism of actions of aspirin analogues in the treatment of glioma cancer
INTRODUCTION: In the past 25 years only modest advancements in glioma treatment have been made, with patient prognosis and median survival time following diagnosis only increasing from 3 to 7 months. A substantial body of clinical and preclinical evidence has suggested a role for aspirin in the treatment of cancer with multiple mechanisms of action proposed including COX 2 inhibition, down regulation of EGFR expression, and NF-κB signaling affecting Bcl-2 expression. However, with serious side effects such as stroke and gastrointestinal bleeding, aspirin analogues with improved potency and side effect profiles are being developed. METHOD: Effects on cell viability following 24 hr incubation of four aspirin derivatives (PN508, 517, 526 and 529) were compared to cisplatin, aspirin and di-aspirin in four glioma cell lines (U87 MG, SVG P12, GOS – 3, and 1321N1), using the PrestoBlue assay, establishing IC50 and examining the time course of drug effects. RESULTS: All compounds were found to decrease cell viability in a concentration and time dependant manner. Significantly, the analogue PN517 (IC50 2mM) showed approximately a twofold increase in potency when compared to aspirin (3.7mM) and cisplatin (4.3mM) in U87 cells, with similar increased potency in SVG P12 cells. Other analogues demonstrated similar potency to aspirin and cisplatin. CONCLUSION: These results support the further development and characterization of novel NSAID derivatives for the treatment of glioma
Sustainable environmental geotechnics practices for a green economy
The revitalisation of the global economy after the Covid-19 era presents environmental geotechnics with the opportunity to reinforce the need for a change in paradigm towards a green, circular economy and to promote aggressively the use and development of sustainable technologies and management practices. This paper aims to assist in this effort by concentrating on several thematic areas where sustainability solutions and future improvements are sought. These include the re-entry of construction and demolition of wastes, excavated materials, industrial wastes and marine sediments into the production cycle and the reuse of existing foundations. Despite the recent trend in advanced countries towards recycling and waste-to-energy thermal treatment, landfills still constitute the most common municipal solid waste management practice, especially in low-and-middle-income countries, and technological solutions to improve their environmental footprint are hereby presented. At the same time, remediation solutions are required to address the multitude of contaminated sites worldwide. Advanced developments that incorporate environmental, economic and social dimensions are expounded by the authors, together with sustainable ground improvement solutions for infrastructure projects conducted in soft and weak soils. The topic of thermo-active geostructures concludes this paper, where, apart from their infrastructure utility, these structures have the potential to contribute to the renewable energy source.Published versionThe second author would like to acknowledge the support of the Office of the Associate Provost for Research and Academic Development at Abu Dhabi University, UAE through grant19300540
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