3,986 research outputs found

    How Does Buzz Build Brands? Investigating the Link between Word of Mouth and Brand Performance

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    To aid in resolving some of the ambiguity in the literature about the impact of different forms of WOM on brand performance, this dissertation investigates how WOM influences three consumer responses to WOM: purchase, WOM retransmission, and additional information search. The author investigates these questions by analyzing a database comprising more than three years of detailed WOM data from a unique, nationally representative panel merged with other secondary sources that provide various measures of brand strength (the American Consumer Satisfaction Index and Harris Interactiveā€™s Equitrend). Using a series of hierarchical regression models, the results from this study reveal numerous insights into the contextual factors that moderate the impact of a WOM episode. For example, negative WOM about a brand has a larger absolute effect on consumer purchase intentions than positive WOM, but positive WOM has a larger positive effect on WOM retransmission than the positive effect of negative WOM. Offline WOM tends to exacerbate the effect of positive and negative brand sentiment on purchase intentions. WOM between stronger social ties tends to have greater impact on brand-related responses than WOM between weak ties, except in the case of motivating additional information search. The results also indicate that strong brands (those with higher levels of brand equity) tend to reap greater benefits from WOM. For example, negative, mixed, or neutral WOM has greater influence on purchase, and WOM from weak social ties about strong brands motivates higher levels of information search than when WOM from weak ties is about weaker brands

    Gene Therapy for Cardiovascular Disease

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    The last decade has seen substantial advances in the development of gene therapy strategies and vector technology for the treatment of a diverse number of diseases, with a view to translating the successes observed in animal models into the clinic. Perhaps the overwhelming drive for the increase in vascular gene transfer studies is the current lack of successful long-term pharmacological treatments for complex cardiovascular diseases. The increase in cardiovascular disease to epidemic proportions has also led many to conclude that drug therapy may have reached a plateau in its efficacy and that gene therapy may represent a realistic solution to a long-term problem. Here, we discuss gene delivery approaches and target diseases

    Age, growth, mortality, and radiometric age validation of gray snapper (Lutjanus griseus) from Louisiana

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    The gray snapper (Lutjanus griseus) is a temperate and tropical reef fish that is found along the Gulf of Mexico and Atlantic coasts of the southeastern United States. The recreational fishery for gray snapper has developed rapidly in south Louisiana with the advent of harvest and seasonal restrictions on the established red snapper (L. campechanus) fishery. We examined the age and growth of gray snapper in Louisiana with the use of cross-sectioned sagittae. A total of 833 specimens, (441 males, 387 females, and 5 of unknown sex) were opportunistically sampled from the recreational fishery from August 1998 to August 2002. Males ranged in size from 222 to 732 mm total length (TL) and from 280 g to 5700 g total weight (TW) and females ranged from 254 to 756 mm TL and from 340 g to 5800 g TW. Both edge analysis and bomb radiocarbon analyses were used to validate otolith-based age estimates. Ages were estimated for 718 individuals; both males and females ranged from 1 to 28 years. The von Bertalanffy growth models derived from TL at age were Lt = 655.4{1ā€“e[ā€“0.23(t)]} for males, Lt = 657.3{1ā€“e[ā€“ 0.21(t)]} for females, and L t = 656.4{1ā€“e[ā€“ 0.22 (t)]} for all specimens of known sex. Catch curves were used to produce a total mortality (Z) estimate of 0.17. Estimates of M calculated with various methods ranged from 0.15 to 0.50; however we felt that M= 0.15 was the most appropriate estimate based on our estimate of Z. Full recruitment to the gray snapper recreational fishery began at age 4, was completed by age 8, and there was no discernible peak in the catch curve dome

    miR-34a-/- mice are susceptible to diet-induced obesity

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    Objective: MicroRNA (miR)āˆ’34a regulates inflammatory pathways, and increased transcripts have been observed in serum and subcutaneous adipose of subjects who have obesity and type 2 diabetes. Therefore, the role of miR-34a in adipose tissue inflammation and lipid metabolism in murine diet-induced obesity was investigated. Methods: Wild-type (WT) and miR-34aāˆ’/āˆ’ mice were fed chow or high-fat diet (HFD) for 24 weeks. WT and miR-34aāˆ’/āˆ’ bone marrow-derived macrophages were cultured in vitro with macrophage colony-stimulating factor (M-CSF). Brown and white preadipocytes were cultured from the stromal vascular fraction (SVF) of intrascapular brown and epididymal white adipose tissue (eWAT), with rosiglitazone. Results: HFD-fed miR-34aāˆ’/āˆ’ mice were significantly heavier with a greater increase in eWAT weight than WT. miR-34aāˆ’/āˆ’ eWAT had a smaller adipocyte area, which significantly increased with HFD. miR-34aāˆ’/āˆ’ eWAT showed basal increases in Cd36, Hmgcr, LxrĪ±, Pgc1Ī±, and Fasn. miR-34aāˆ’/āˆ’ intrascapular brown adipose tissue had basal reductions in c/ebpĪ± and c/ebpĪ², with in vitro miR-34aāˆ’/āˆ’ white adipocytes showing increased lipid content. An F4/80high macrophage population was present in HFD miR-34aāˆ’/āˆ’ eWAT, with increased IL-10 transcripts and serum IL-5 protein. Finally, miR-34aāˆ’/āˆ’ bone marrow-derived macrophages showed an ablated CXCL1 response to tumor necrosis factor-Ī±. Conclusions: These findings suggest a multifactorial role of miR-34a in controlling susceptibility to obesity, by regulating inflammatory and metabolic pathways

    Phylogenetic diversity (PD) and biodiversity conservation: some bioinformatics challenges

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    Biodiversity conservation addresses information challenges through estimations encapsulated in measures of diversity. A quantitative measure of phylogenetic diversity, ā€œPDā€, has been defined as the minimum total length of all the phylogenetic branches required to span a given set of taxa on the phylogenetic tree (Faith 1992a). While a recent paper incorrectly characterizes PD as not including information about deeper phylogenetic branches, PD applications over the past decade document the proper incorporation of shared deep branches when assessing the total PD of a set of taxa. Current PD applications to macroinvertebrate taxa in streams of New South Wales, Australia illustrate the practical importance of this definition. Phylogenetic lineages, often corresponding to new, ā€œcrypticā€, taxa, are restricted to a small number of stream localities. A recent case of human impact causing loss of taxa in one locality implies a higher PD value for another locality, because it now uniquely represents a deeper branch. This molecular-based phylogenetic pattern supports the use of DNA barcoding programs for biodiversity conservation planning. Here, PD assessments side-step the contentious use of barcoding-based ā€œspeciesā€ designations. Bio-informatics challenges include combining different phylogenetic evidence, optimization problems for conservation planning, and effective integration of phylogenetic information with environmental and socio-economic data

    Topological Andr\'e-Quillen homology for cellular commutative SS-algebras

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    Topological Andr\'e-Quillen homology for commutative SS-algebras was introduced by Basterra following work of Kriz, and has been intensively studied by several authors. In this paper we discuss it as a homology theory on CW SS-algebras and apply it to obtain results on minimal atomic pp-local SS-algebras which generalise those of Baker and May for pp-local spectra and simply connected spaces. We exhibit some new examples of minimal atomic SS-algebras.Comment: Final revision, a version will appear in Abhandlungen aus dem Mathematischen Seminar der Universitaet Hambur

    Images in cardiovascular medicine : multiphoton microscopy for three-dimensional imaging of lymphocyte recruitment into apolipoprotein-E-deficient mouse carotid artery

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    Two recent elegant studies have shown that in apolipoprotein-Eā€“ deficient mice, the lamina adventitia is a major site of arterial wall inflammation associated with lymphocyte infiltration into atherosclerotic arteries and with formation of adventitial lymphoid-like tissues.1,2 These results suggest that lymphocyte responses in the lamina adventitia may play a crucial role in atherosclerosis development.1,

    Improved gene delivery to human saphenous vein cells and tissue using a peptide-modified adenoviral vector

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    The establishment of efficient gene delivery to target human tissue is a major obstacle for transition of gene therapy from the pre-clinical phases to the clinic. The poor long-term patency rates for coronary artery bypass grafting (CABG) is a major clinical problem that lacks an effective and proven pharmacological intervention. Late vein graft failure occurs due to neointima formation and accelerated atherosclerosis. Since CABG allows a clinical window of opportunity to genetically modify vein ex vivo prior to grafting it represents an ideal opportunity to develop gene-based therapies. Adenoviral vectors have been frequently used for gene delivery to vein ex vivo and pre-clinical studies have shown effective blockade in neointima development by overexpression of candidate therapeutic genes. However, high titers of adenovirus are required to achieve sufficient gene delivery to provide therapeutic benefit. Improvement in the uptake of adenovirus into the vessel wall would therefore be of benefit. Here we determined the ability of an adenovirus serotype 5 vector genetically-engineered with the RGD-4C integrin targeting peptide inserted into the HI loop (Ad-RGD) to improve the transduction of human saphenous vein smooth muscle cells (HSVSMC), endothelial cells (HSVEC) and intact saphenous vein compared to a non-modified virus (Ad-CTL). We exposed each cell type to virus for 10, 30 or 60 mins and measured transgene at 24 h post infection. For both HSVSMC and HSVEC Ad-RGD mediated increased transduction, with the largest increases observed in HSVSMC. When the experiments were repeated with intact human saphenous vein (the ultimate clinical target for gene therapy), again Ad-RGD mediated higher levels of transduction, at all clinically relevant exposures times (10, 30 and 60 mins tissue:virus exposure). Our study demonstrates the ability of peptide-modified Ad vectors to improve transduction to human vein graft cells and tissue and has important implications for gene therapy for CABG

    Galois theory and Lubin-Tate cochains on classifying spaces

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    We consider brave new cochain extensions F(BG +,R) ā†’ F(EG +,R), where R is either a Lubin-Tate spectrum E n or the related 2-periodic Morava K-theory K n , and G is a finite group. When R is an Eilenberg-Mac Lane spectrum, in some good cases such an extension is a G-Galois extension in the sense of John Rognes, but not always faithful. We prove that for E n and K n these extensions are always faithful in the K n local category. However, for a cyclic p-group C p r, the cochain extension F(BC p r +,E n ) ā†’ F(EC p r +, E n ) is not a Galois extension because it ramifies. As a consequence, it follows that the E n -theory Eilenberg-Moore spectral sequence for G and BG does not always converge to its expected target

    The Temperature and Pressure Dependence of Nickel Partitioning between Olivine and Silicate Melt

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    We measured Ni partitioning between olivine and melt, D^(ol/liq)_(Ni), in experiments on mid-ocean ridge basalt (MORB) encapsulated in olivine at pressures from 1 atm to 3Ā·0 GPa and temperatures from 1400 to 1550Ā°C. We present a series of experiments where the temperature (T) at each pressure (P) was selected so that the liquid composition remained approximately constant over the entire Pā€“T range. This approach allowed us to investigate the effects of T and P on D^(ol/liq)_(Ni), independent of substantial changes in liquid composition. Our experiments show that for a liquid with āˆ¼18 wt% MgO, D^(ol/liq)_(Ni) decreases from 5Ā·0 to 3Ā·8 as the temperature increases from 1400 to 1550Ā°C. Fitting our experimental results and literature data to thermodynamic expressions for D^(ol/liq)_(Ni) as a function of both temperature and liquid composition shows that the small variations in liquid composition in our experiments account for little of the observed variation of D^(ol/liq)_(Ni). Because the changes in volume and heat capacity of the exchange reaction MgSi_(0-5)O^(ol)_2 + D^(ol/liq)_(Ni) ā†” NiSi_(0-5)O^(ol)_2 + MgO^(liq) are small, D^(molar)_(Ni), the Ni partition coefficient on a molar basis, is well described by In(D^(molar)_(Ni))=-^(Ī”_rHo_(T_(ref)),P_(ref)/_(RT) + ^Ī”_rSo_(T_(ref),P_(ref))/_R - In (X^(liq)_(MgO)/X^(ol)_(MgSi)_(0-5)O_2) with Ī”_rH^o_T_(ref),_P_(ref)/_R = 4375 K and Ī”_rSo_T_(ref),_P_(ref)/_R = ā€“2Ā·023 for our data (Ī”_rH^o_T_(ref),_P_(ref)/_R = 4338 K and Ī”_rSo_T_(ref),_P_(ref)/_R = ā€“1Ā·956 for our experiments combined with a compilation of literature data). This expression is easy to use and applicable to a wide range of pressures, temperatures, and phase compositions. Based on our results and data from the literature, the temperature dependence of D^(ol/liq)_(Ni) leads to the prediction that when a deep partial melt from a peridotitic mantle source is brought to low pressure and cooled, the first Mg-rich olivines to crystallize can have significantly higher NiO contents than those in the residual source from which the melt was extracted. This enrichment in Ni is driven by the difference between the temperature of low-pressure crystallization and the temperature of melt extraction from the residue. The average observed enrichment of Ni in forsteritic olivine phenocrysts from Hawaiiā€”relative to the typical olivines from mantle peridotitesā€”is consistent with a simple scenario of high-temperature partial melting of an olivine-bearing source at the base of the lithosphere followed by low-temperature crystallization of olivine. The most extreme enrichments of Ni in Hawaiian olivine phenocrysts and the lower Ni contents of some olivines can also be explained by the known variability of Ni contents of olivines from mantle peridotites via the same simple scenario. Although we cannot rule out alternative hypotheses for producing the high-Ni olivines observed in Hawaii and elsewhere, these processes or materials are unnecessary to account for NiO enrichments in olivine. The absolute temperature, in addition to the difference between the temperature of melt segregation from the residue and the temperature of low-pressure crystallization, is a significant factor in determining the degree of Ni enrichment in olivine phenocrysts relative to the olivines in the mantle source. The moderate Ni enrichment observed in most komatiitic olivines compared with those of Hawaii may result from the higher absolute temperatures required to generate MgO-rich komatiitic melts. Observed NiO enrichments in early crystallizing komatiitic olivine are consistent with their high temperatures of crystallization and with a deep origin for the komatiite parental melts
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