2,159 research outputs found

    Interior regularity criteria for suitable weak solutions of the Navier-Stokes equations

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    We present new interior regularity criteria for suitable weak solutions of the 3-D Navier-Stokes equations: a suitable weak solution is regular near an interior point zz if either the scaled Lx,tp,qL^{p,q}_{x,t}-norm of the velocity with 3/p+2/q23/p+2/q\leq 2, 1q1\leq q\leq \infty, or the Lx,tp,qL^{p,q}_{x,t}-norm of the vorticity with 3/p+2/q33/p+2/q\leq 3, 1q<1 \leq q < \infty, or the Lx,tp,qL^{p,q}_{x,t}-norm of the gradient of the vorticity with 3/p+2/q43/p+2/q\leq 4, 1q1 \leq q, 1p1 \leq p, is sufficiently small near zz

    Analysis of the impact of financial crises on Ouro Scheffer's jewelry sales

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    This article studies financial crises and their impact on the main types of financial investment. Specifically, the objective of this study is to analyze the impact that financial crises generated in purchase of jewelry at Ouro Scheffer. It was therefore necessary to first revise the concept of main types of investment in variable income and fixed income, as well as a history of gold, and to analyze the main financial crises. Applied and quantitative research was then carried out with an analysis of three temporal series: gold, Ibovespa and Ouro Scheffer''s jewelry sales revenue. The results found that the main financial crises of 1999 and 2008 had an impact on the jewelry sales temporal series. It was also possible to determine that these crises generated an impact on the gold and Ibovespa temporal series

    Tubular structures of GaS

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    In this Brief Report we demonstrate, using density-functional tight-binding theory, that gallium sulfide (GaS) tubular nanostructures are stable and energetically viable. The GaS-based nanotubes have a semiconducting direct gap which grows towards the value of two-dimensional hexagonal GaS sheet and is in contrast to carbon nanotubes largely independent of chirality. We further report on the mechanical properties of the GaS-based nanotubes

    Acquired resistance of human T cells to sulfasalazine: stability of the resistant phenotype and sensitivity to non-related DMARDs.

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    2.5 weeks) resumption of SSZ resistance and ABCG2 expression as in the original CEM/SSZ cells. CEM/SSZ cells displayed diminished sensitivity to the DMARDs leflunomide (5.1-fold) and methotrexate (1.8-fold), were moderately more sensitive (1.6-2.0 fold) to cyclosporin A and chloroquine, and markedly more sensitive (13-fold) to the glucocorticoid dexamethasone as compared with parental CEM cells. CONCLUSION: The drug efflux pump ABCG2 has a major role in conferring resistance to SSZ. The collateral sensitivity of SSZ resistant cells for some other (non-related) DMARDs may provide a further rationale for sequential mono- or combination therapies with distinct DMARDs upon decreased efficacy of SSZ

    A Cognitive Model of an Epistemic Community: Mapping the Dynamics of Shallow Lake Ecosystems

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    We used fuzzy cognitive mapping (FCM) to develop a generic shallow lake ecosystem model by augmenting the individual cognitive maps drawn by 8 scientists working in the area of shallow lake ecology. We calculated graph theoretical indices of the individual cognitive maps and the collective cognitive map produced by augmentation. The graph theoretical indices revealed internal cycles showing non-linear dynamics in the shallow lake ecosystem. The ecological processes were organized democratically without a top-down hierarchical structure. The steady state condition of the generic model was a characteristic turbid shallow lake ecosystem since there were no dynamic environmental changes that could cause shifts between a turbid and a clearwater state, and the generic model indicated that only a dynamic disturbance regime could maintain the clearwater state. The model developed herein captured the empirical behavior of shallow lakes, and contained the basic model of the Alternative Stable States Theory. In addition, our model expanded the basic model by quantifying the relative effects of connections and by extending it. In our expanded model we ran 4 simulations: harvesting submerged plants, nutrient reduction, fish removal without nutrient reduction, and biomanipulation. Only biomanipulation, which included fish removal and nutrient reduction, had the potential to shift the turbid state into clearwater state. The structure and relationships in the generic model as well as the outcomes of the management simulations were supported by actual field studies in shallow lake ecosystems. Thus, fuzzy cognitive mapping methodology enabled us to understand the complex structure of shallow lake ecosystems as a whole and obtain a valid generic model based on tacit knowledge of experts in the field.Comment: 24 pages, 5 Figure

    In Vivo Downregulation of Innate and Adaptive Immune Responses in Corneal Allograft Rejection by HC-HA/PTX3 Complex Purified From Amniotic Membrane

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    Citation: He H, Tan Y, Duffort S, Perez VL, Tseng SCG. In vivo downregulation of innate and adaptive immune responses in corneal allograft rejection by HC-HA/PTX3 complex purified from amniotic membrane. Invest Ophthalmol Vis Sci. 2014;55:164755: -165655: . DOI:10.1167 PURPOSE. Heavy chain-hyaluronic acid (HC-HA)/PTX3 purified from human amniotic membrane (AM) was previously observed to suppress inflammatory responses in vitro. We now examine whether HC-HA/PTX3 is able to exert a similar effect in vivo, using murine models for keratitis and corneal allograft rejection. METHODS. The in vitro effect of HC-HA/PTX3 was tested using OTII ovalbumin (OVA) transgenic, purified CD4 þ T cells, or IFN-c/lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Cytokine production was measured by ELISA, while cell surface markers and cell proliferation were determined by flow cytometry. In vivo effects of HC-HA/PTX3 were analyzed by quantifying the recruitment of enhanced green fluorescence-labeled macrophages and by measuring the expression of arginase 1 (Arg-1), IL-10, and IL-12 in LPS-induced keratitis in the macrophage Fas-induced apoptosis (Mafia) mouse. The effect of corneal allograft survival in a complete major histocompatibility complex (MHC) mismatched mouse model was assessed by grading corneal opacification. RESULTS. In vitro studies demonstrated that HC-HA/PTX3 significantly enhanced the expansion of FOXP3 T cells and suppressed cell proliferation and protein expression of IFN-c, IL-2, CD25, and CD69 in activated CD4 þ T cells. Furthermore, immobilized HC-HA/PTX3 significantly upregulated IL-10 gene expression but downregulated that of IL-12 and IL-23 in activated RAW264.7 cells. Finally, in vivo subconjunctival injection of HC-HA/PTX3 significantly prolonged corneal allograft survival, suppressed macrophage infiltration, and promoted M2 polarization by upregulating Arg-1 and IL-10 but downregulating IL-12. CONCLUSIONS. HC-HA/PTX3 can suppress inflammatory responses in vivo by modulating both innate and adaptive immunity of macrophages and CD4 þ T cells

    Modeling resilience and sustainability in ancient agricultural systems

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    The reasons why people adopt unsustainable agricultural practices, and the ultimate environmental implications of those practices, remain incompletely understood in the present world. Archaeology, however, offers unique datasets on coincident cultural and ecological change, and their social and environmental effects. This article applies concepts derived from ecological resilience thinking to assess the sustainability of agricultural practices as a result of long-term interactions between political, economic, and environmental systems. Using the urban center of Gordion, in central Turkey, as a case study, it is possible to identify mismatched social and ecological processes on temporal, spatial, and organizational scales, which help to resolve thresholds of resilience. Results of this analysis implicate temporal and spatial mismatches as a cause for local environmental degradation, and increasing extralocal economic pressures as an ultimate cause for the adoption of unsustainable land-use practices. This analysis suggests that a research approach that integrates environmental archaeology with a resilience perspective has considerable potential for explicating regional patterns of agricultural change and environmental degradation in the past

    Navier and stokes meet the wavelet

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    We work in the space ℱ = ℱ ε of divergence-free measurable vector fields on R 3 complete in the norm ‖ ‖′, where for some fixed ε>0. B(x, R) is the ball of radius R centered at x . Given an initial velocity distribution (0) in ℱ, we find ( x,t ) for 0≦ t ≦ T = T (‖ v (0)‖'), T >0, such that ( x,t ) is the unique strong solution of the Navier-Stokes equations, in a suitable sense.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46484/1/220_2005_Article_BF02097391.pd

    Dietary polyunsaturated fat intake is associated with low-density lipoprotein size, but not with susceptibility to oxidation in subjects with impaired glucose metabolism and type II diabetes: the Hoorn study

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    OBJECTIVE: A high monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) intake is associated with lower plasma low-density lipoprotein (LDL)-cholesterol. However, PUFA may increase the susceptibility of LDL to undergo oxidative modifications. The aim of this study was to analyze the association of habitual dietary fat intake with LDL size and oxidizability. DESIGN: Cross-sectional. SETTING: Cohort study. SUBJECTS: Seven hundred and fifty-eight subjects with normal, impaired glucose metabolism and type II diabetes. INTERVENTIONS: Mean LDL size was measured by high-performance gel-filtration chromatography. In vitro oxidizability of LDL was determined by measuring lag time, reflecting the resistance of LDL to copper-induced oxidation. Information about dietary fat intake was obtained by a validated food frequency questionnaire. RESULTS: PUFA intake (energy percent) was significantly and negatively associated with LDL size in subjects with type II diabetes (standardized beta (95% confidence interval) -0.17 (-0.28;-0.06)) and impaired glucose metabolism - although not statistically significant - (-0.09 (-0.24;0.05)), but not in subjects with normal glucose metabolism (0.01 (-0.10;0.12)) (P-value for interaction=0.02). No significant associations were observed for total, saturated fat and MUFA intake with LDL size. Intake of fat was associated with lag time; however, the small magnitude of the associations suggested that the composition of dietary fat is not a major factor affecting lag time. The same association with lag time was observed in all three glucose metabolism categories. CONCLUSIONS: In individuals with abnormal glucose metabolism, higher PUFA intake is associated with smaller LDL particle size, but does not alter the susceptibility of LDL to in vitro oxidation. SPONSORSHIP: Dutch Diabetes Research Foundation, and the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)
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