2,735 research outputs found

    The Bohr radius of the nn-dimensional polydisk is equivalent to lognn\sqrt{\frac{\log n}{n}}

    Get PDF
    We show that the Bohr radius of the polydisk Dn\mathbb D^n behaves asymptotically as (logn)/n\sqrt{(\log n)/n}. Our argument is based on a new interpolative approach to the Bohnenblust--Hille inequalities which allows us to prove that the polynomial Bohnenblust--Hille inequality is subexponential.Comment: The introduction was expanded and some misprints correcte

    Role of Membrane GM1 on Early Neuronal Membrane Actions of Aβ During Onset of Alzheimer\u27s Disease

    Get PDF
    The ability of beta-amyloid peptide (Aβ) to disrupt the plasma membrane through formation of pores and membrane breakage has been previously described. However, the molecular determinants for these effects are largely unknown. In this study, we examined if the association and subsequent membrane perforation induced by Aβ was dependent on GM1levels. Pretreatment of hippocampal neurons with D-PDMP decreased GM1 and Aβ clustering at the membrane (Aβ fluorescent-punctas/20 μm, control = 16.2 ± 1.1 vs. D-PDMP = 6.4 ± 0.4, p \u3c 0.001). Interestingly, membrane perforation with Aβ occurred with a slower time course when the GM1 content was diminished (time to establish perforated configuration (TEPC) (min): control = 7.8 ± 2 vs. low GM1 = 12.1 ± 0.5, p \u3c 0.01), suggesting that the presence of GM1 in the membrane can modulate the distribution and the membrane perforation by Aβ. On the other hand, increasing GM1 facilitated the membrane perforation (TEPC: control = 7.8 ± 2 vs. GM1 = 6.2 ± 1 min, p \u3c 0.05). Additionally, using Cholera Toxin Subunit-B (CTB) to block the interaction of Aβ with GM1 attenuated membrane perforation significantly. Furthermore, pretreatment with CTB decreased the membrane association of Aβ (fluorescent-punctas/20 μm, Aβ: control = 14.8 ± 2.5 vs. CTB = 8 ± 1.4, p \u3c 0.05), suggesting that GM1 also plays a role in both association of Aβ with the membrane and in perforation. In addition, blockade of the Aβ association with CTB inhibited synaptotoxicity. Taken together, our results strongly suggest that membrane lipid composition can affect the ability of Aβ to associate and subsequently perforate the plasma membrane thereby modulating its neurotoxicity in hippocampal neurons

    Separation of bitumen from Utah tar sands by a hot water digestion-flotation technique

    Get PDF
    Journal ArticleTar sand deposits in the state of Utah contain more than 25 billion bbl of in-place bitumen. Although 30 times smaller than the well-known Athabasca tar sands, Utah tar sands do represent a significant domestic energy resource comparable to the national crude oil reserves (31.3 billion bbl). Based upon a detailed analysis of the physical and chemical properties of both the bitumen and the sand, a hot-water separation process for Utah tar sands is currently being developed in our laboratories at the University of Utah. This process involves intense agitation of the tar sand in a hot caustic solution and subsequent separation of the bitumen by a modified froth flotation technique. Experimental results with an Asphalt Ridge, Utah, tar sand sample indicated that percent solids and caustic concentration were the two most important variables controlling the performance of the digestion stage. These variables were identified by means of an experimental factorial design, in which coefficients of separation greater than 0.90 were realized. Although preliminary in nature, the experimental evidence gathered in this investigation seems to indicate that a hot-water separation process for Utah tar sands would allow for the efficient utilization of this important energy resource

    Preferencias hacia carne de cordero en supermercados de Temuco, región de la Araucanía, Chile

    Get PDF
    Lobos, G (Lobos, German). Univ Talca, Escuela Ingn Comercial, Talca, ChileThe low levels of consumption of lamb meat in Chile suggest the need for studies on consumer preferences in order to orient production. A study with this object was carried out to evaluate preferences for various cuts, breeds, state (fresh or frozen) and price of lamb's meat among supermarket buyers in Temuco, Chile, and the existence of different market segments, through a survey of 400 persons. Using a fractional factorial design for conjoint analysis, it was determined that the state of the meat was more important than the cut, the price and the breed, with a preference for meat in half carcasses and quarters, Araucano lamb, fresh, at a medium price level. Four consumer segments were distinguished by analysis of hierarchic conglomerates. The majority group (47.7%) was sensitive to the state and the cut, with preference for meat in quarters, fresh, Texel breed. The second group (25.3%) was sensitive to the breed, presenting the strongest preferences for meat in whole carcass, fresh, Araucano lamb. The third group (14.3%) was sensitive to the price, preferred meat in quarters, fresh, Araucano lamb. The minority group (12.7%) was sensitive to the state and price, preferring meat in quarters, Texel breed, and was the only group which preferred frozen meat and would pay a higher price. The segments were distinguished by age, ethnic origin and satisfaction with food-related life. Thus the commercialisation strategy for lamb in supermarkets in Temuco should concentrate principally on the sale of fresh meat cut in quarter

    Understanding the links between diversity and creativity as assessed in the boroughs of London

    Get PDF
    This paper analyses the links between creativity and diversity in the different boroughs of London. Based on rich data from the UK Census of Population of 2011 and other sources, we specifically analysed the correlations between creativity and diversity within the London boroughs. The main results of this study indicate that there is no direct correlation between creativity and diversity. Some significant correlations have been observed, however, between variables that shape such indices. Namely, the “creative class” tend to live in more diverse, more heterogeneous neighbourhoods (alongside people from many different countries) and they are more prepared to tolerate such diverse environments. The study also shows that diversity of geographical origin (measured by country of origin) is a more relevant factor for boosting creativity than variables such as religious diversity. This article contributes to the theoretical field of research exploring the impact of diversity on creative people and cities

    Evolving Marketization, Societal Trends, and Indicators in Chile and the Andean Region

    Get PDF
    The effects of marketization on Chile and the broader Andean Region are profound and systemic. Key indicators reveal trends toward economic growth, improved social conditions, and sustainable development. The marketization of the Andean Region, however, is a complex and evolving process. We report on recent developments, which necessitate some reflection on trends and prognoses. In particular, while marketization has led to better education, increased social mobility, and enhanced well-being, one of the most important challenges facing countries in the region is ensuring that the benefits of marketization are shared equitably among all members of society. Priorities include further improvements in access to education and other social services for those who have been traditionally marginalized, and creating systemic changes to enhance sustainable development. Inclusive, collaborative, and pragmatic leadership by catalytic institutions, that transcend political posturing, is paramount going forward, and will require constructive engagement with all stakeholders of the region
    corecore