1,619 research outputs found
Determinants of Effectiveness and Success for EBay Auctions
This research investigates eBay auction properties that influence auction outcomes: effectiveness (ability to attract bidders) and success (whether the item was actually sold in the auction). Hundreds of auctions (1,273) for three popular financial calculators—the HP 12c, the HP 10b and BA II plus—were examined to assess the impact of these auction properties. Findings show that utilization of certain auction features influence both outcomes. These features include starting price and reserve price for both calculators. Other features impact only auction effectiveness: wear and the presence of a picture for the HP10 and BA II plus; and wear and ability to pay with credit cards for the HP 12c. Further, others auction factors influence only auction success: abnormally high first bids and whether the seller is a recognized company rather than an individual for the HP 10b and BA II plus; and the length of time the seller has been selling on eBay, the presence of a picture, and whether the seller was a recognized company rather than an individual for the HP12c
Toxicity and Positivity Across Genders: Feminine, Masculine, and Androgynous Consumer Characteristics
A research model is designed to assess toxic and positive consumer behavior based on masculinity, femininity, and androgyny. New definitions of androgyny are developed, resulting in two types of consumer androgyny – hypo-androgyny and hyper-androgyny. Also, the hypotheses of the research model are assessed using a snowball sample beginning with young consumers enrolled in upper-division marketing classes at a large U.S. university. Results show important insights on the toxicity of certain consumer characteristics not only in individuals who measure high in masculinity, but also those others included in this study who are more feminine or androgynous. Results also offer findings indicating positive consumer characteristics for all consumer classifications of this research
Oxygen Glucose Deprivation in Rat Hippocampal Slice Cultures Results in Alterations in Carnitine Homeostasis and Mitochondrial Dysfunction
Mitochondrial dysfunction characterized by depolarization of mitochondrial membranes and the initiation of mitochondrial-mediated apoptosis are pathological responses to hypoxia-ischemia (HI) in the neonatal brain. Carnitine metabolism directly supports mitochondrial metabolism by shuttling long chain fatty acids across the inner mitochondrial membrane for beta-oxidation. Our previous studies have shown that HI disrupts carnitine homeostasis in neonatal rats and that L-carnitine can be neuroprotective. Thus, this study was undertaken to elucidate the molecular mechanisms by which HI alters carnitine metabolism and to begin to elucidate the mechanism underlying the neuroprotective effect of L-carnitine (LCAR) supplementation. Utilizing neonatal rat hippocampal slice cultures we found that oxygen glucose deprivation (OGD) decreased the levels of free carnitines (FC) and increased the acylcarnitine (AC): FC ratio. These changes in carnitine homeostasis correlated with decreases in the protein levels of carnitine palmitoyl transferase (CPT) 1 and 2. LCAR supplementation prevented the decrease in CPT1 and CPT2, enhanced both FC and the AC: FC ratio and increased slice culture metabolic viability, the mitochondrial membrane potential prior to OGD and prevented the subsequent loss of neurons during later stages of reperfusion through a reduction in apoptotic cell death. Finally, we found that LCAR supplementation preserved the structural integrity and synaptic transmission within the hippocampus after OGD. Thus, we conclude that LCAR supplementation preserves the key enzymes responsible for maintaining carnitine homeostasis and preserves both cell viability and synaptic transmission after OGD
Validation of weighed records and other methods of dietary assessment using the 24 h urine nitrogen technique and other biological markers
Blood Meal Analysis to Identify Reservoir Hosts for Amblyomma americanum Ticks
Blood meal analysis identified white-tailed deer as hosts for ticks that carry zoonotic pathogens
Telomere disruption results in non-random formation of de novo dicentric chromosomes involving acrocentric human chromosomes
Copyright: © 2010 Stimpson et al.Genome rearrangement often produces chromosomes with two centromeres (dicentrics) that are inherently unstable because of bridge formation and breakage during cell division. However, mammalian dicentrics, and particularly those in humans, can be quite stable, usually because one centromere is functionally silenced. Molecular mechanisms of centromere inactivation are poorly understood since there are few systems to experimentally create dicentric human chromosomes. Here, we describe a human cell culture model that enriches for de novo dicentrics. We demonstrate that transient disruption of human telomere structure non-randomly produces dicentric fusions involving acrocentric chromosomes. The induced dicentrics vary in structure near fusion breakpoints and like naturally-occurring dicentrics, exhibit various inter-centromeric distances. Many functional dicentrics persist for months after formation. Even those with distantly spaced centromeres remain functionally dicentric for 20 cell generations. Other dicentrics within the population reflect centromere inactivation. In some cases, centromere inactivation occurs by an apparently epigenetic mechanism. In other dicentrics, the size of the alpha-satellite DNA array associated with CENP-A is reduced compared to the same array before dicentric formation. Extrachromosomal fragments that contained CENP-A often appear in the same cells as dicentrics. Some of these fragments are derived from the same alpha-satellite DNA array as inactivated centromeres. Our results indicate that dicentric human chromosomes undergo alternative fates after formation. Many retain two active centromeres and are stable through multiple cell divisions. Others undergo centromere inactivation. This event occurs within a broad temporal window and can involve deletion of chromatin that marks the locus as a site for CENP-A maintenance/replenishment.This work was supported by the Tumorzentrum Heidelberg/Mannheim grant (D.10026941)and by March of Dimes Research Foundation grant #1-FY06-377 and NIH R01 GM069514
Cryptosporidium Priming Is More Effective than Vaccine for Protection against Cryptosporidiosis in a Murine Protein Malnutrition Model
Cryptosporidium is a major cause of severe diarrhea, especially in malnourished children. Using a murine model of C. parvum oocyst challenge that recapitulates clinical features of severe cryptosporidiosis during malnutrition, we interrogated the effect of protein malnutrition (PM) on primary and secondary responses to C. parvum challenge, and tested the differential ability of mucosal priming strategies to overcome the PM-induced susceptibility. We determined that while PM fundamentally alters systemic and mucosal primary immune responses to Cryptosporidium, priming with C. parvum (106 oocysts) provides robust protective immunity against re-challenge despite ongoing PM. C. parvum priming restores mucosal Th1-type effectors (CD3+CD8+CD103+ T-cells) and cytokines (IFNγ, and IL12p40) that otherwise decrease with ongoing PM. Vaccination strategies with Cryptosporidium antigens expressed in the S. Typhi vector 908htr, however, do not enhance Th1-type responses to C. parvum challenge during PM, even though vaccination strongly boosts immunity in challenged fully nourished hosts. Remote non-specific exposures to the attenuated S. Typhi vector alone or the TLR9 agonist CpG ODN-1668 can partially attenuate C. parvum severity during PM, but neither as effectively as viable C. parvum priming. We conclude that although PM interferes with basal and vaccine-boosted immune responses to C. parvum, sustained reductions in disease severity are possible through mucosal activators of host defenses, and specifically C. parvum priming can elicit impressively robust Th1-type protective immunity despite ongoing protein malnutrition. These findings add insight into potential correlates of Cryptosporidium immunity and future vaccine strategies in malnourished children
Visual arguments in film
Nuestro objetivo es señalar algunas diferencias entre los argumentos verbales y visuales, y promover la perspectiva retórica de la argumentación, yendo más allá de la relevancia de la lógica y de la pragmática. En nuestra opinión, si ha de ser racional y aceptable como argumentación (visual), un film debe dirigirse a espectadores que tienen creencias informadas sobre el tema visto en la pantalla y sobre las limitaciones y las convenciones del medio. En nuestras reflexiones, aplicamos el análisis retórico al cine como un acto simbólico, humano y comunicativo que a veces puede entenderse como un argumento trazado visualmente. Como mezcla de estímulos visuales, auditivos y verbales, el film exige una interpretación y una (re)construcción activas y complejas. Nuestra sugerencia es concentrarse en cinco elementos diferentes, pero relacionados entre sí. La reconstrucción y la evaluación del argumento visual se basarán en esos elementos, y todo el proceso constituirá una argumentación visual.Our aim is to point out some differences between verbal and visual
arguments, promoting the rhetorical perspective of argumentation beyond the relevance
of logic and pragmatics. In our view, if it is to be rational and successful,
film as (visual) argumentation must be addressed to spectators who hold informed
beliefs about the theme watched on the screen and the medium’s constraints and
conventions. In our reflections to follow, we apply rhetorical analysis to film as a
symbolic, human, and communicative act that may sometimes be understood as a
visually laid out argument. As a mixture of visual, auditory, and verbal stimuli, film
demands active and complex interpretation and (re)construction. Our suggestion is
to focus on five different but interrelated elements. The reconstruction and evaluation
of the visual argument will be based on those elements, and the whole process
will be one of visual argumentation
- …