901 resultados para Null-Prep phenomenon
Resumo:
LCC Market Development - In 1996 low cost airlines (LCCs) accounted for only 1.4% of intra-European Union capacity. By the end of 2002, low cost airlines had captured 12% of all intra-EU capacity - Currently LCCs have a 30% market share of scheduled European point-to-point passengers. According to AEA forecasts, the LC market is expected to increase to 43% of European traffic by 2011. - In 2006 140 million passengers were carried by LCCs. - Low-fare airlines have increased their presence from 13% of city pairs in 2003 to 26% in 2007. 96% of new city-pairs between 2005 and 2007 were added by LCCs. - The United Kingdom still sees the highest number of low-cost flights, followed by Spain, which has been making up a lot of ground over the last year. This is followed by Italy and Germany with slightly fewer flights. These four countries contribute to roughly three quarters of low-cost departures. France is fifth in this list with only 5% of LC flights. - easyJet and Ryanair continue to be the biggest players in the European LCC market accounting for about 40% of all LCC capacity. The top two are followed by Airberlin, which contributes another 10% leaving three carriers in control of half the European low-cost market.
Resumo:
Most current research into therapeutic approaches to muscle diseases involves the use of the mouse as an experimental model. Furthermore, a major strategy to alleviate myopathic symptoms through enhancing muscle growth and regeneration is to inhibit the action of myostatin (Mstn), a transforming growth factor-beta (TGF-beta) family member that inhibits muscle growth. Presently, however, no study has expanded the morphological analysis of mouse skeletal muscle beyond a few individual muscles of the distal hindlimb, through which broad conclusions have been based. Therefore, we have initially undertaken an expansive analysis of the skeletal musculature of the mouse forelimb and highlighted the species-specific differences between equivalent muscles of the rat, another prominently used experimental model. Subsequently, we examined the musculature of the forelimb in both young and old adult wild-type (mstn(+/+)) and myostatin null (mstn(-/-)) mice and assessed the potential beneficial and detrimental effects of myostatin deletion on muscle morphology and composition during the aging process. We showed that: (1) the forelimb muscles of the mouse display a more glycolytic phenotype than those of the rat; (2) in the absence of myostatin, the induced myofiber hyperplasia, hypertrophy, and glycolytic conversion all occur in a muscle-specific manner; and, importantly, (3) the loss of myostatin significantly alters the dynamics of postnatal muscle growth and impairs age-related oxidative myofiber conversion.
Resumo:
When Campylobacter jejuni cultures that had been grown in broth at 39degreesC were subcultured into fresh medium at 30degreesC, there was a transient period of growth followed by a decline in viable-cell numbers before growth resumed once more. We propose that this complex behavior is the net effect of the growth of inoculum cells followed by a loss of viability due to oxidative stress and the subsequent emergence of a spontaneously arising mutant population that takes over the culture.
Resumo:
Emotion processing deficits can cause catastrophic damage to a person's ability to interact socially. While it is known that older adults have difficulty identifying facial emotions, it is still not clear whether this difficulty extends to identification of the emotion conveyed by prosody. This study investigated whether the ability of older adults to decode emotional prosody falls below that of young adults after controlling for loss of hearing sensitivity and key features of cognitive ageing. Apart from frontal lobe load, only verbal IQ was associated with the age-related reduction in performance displayed by older participants, but a notable deficit existed after controlling for its effects. It is concluded that older adults may indeed have difficulty deducing the emotion conveyed by prosody, and that while this difficulty can be exaggerated by some aspects of cognitive ageing, it is primary in origin.
Resumo:
High-span individuals (as measured by the operation span [CSPAN] technique) are less likely than low-span individuals to notice their own names in an unattended auditory stream (A. R. A. Conway, N. Cowan, & M F. Bunting, 2001). The possibility that OSPAN accounts for individual differences in auditory distraction on an immediate recall test was examined. There was no evidence that high-OSPAN participants were more resistant to the disruption caused by irrelevant speech in serial or in free recall. Low-OSPAN participants did, however, make more semantically related intrusion errors from the irrelevant sound stream in a free recall test (Experiment 4). Results suggest that OSPAN mediates semantic components of auditory distraction dissociable from other aspects of the irrelevant sound effect.
Resumo:
The THz water content index of a sample is defined and advantages in using such metric in estimating a sample's relative water content are discussed. The errors from reflectance measurements performed at two different THz frequencies using a quasi-optical null-balance reflectometer are propagated to the errors in estimating the sample water content index.
Resumo:
We consider a quantity κ(Ω)—the distance to the origin from the null variety of the Fourier transform of the characteristic function of Ω. We conjecture, firstly, that κ(Ω) is maximised, among all convex balanced domains of a fixed volume, by a ball, and also that κ(Ω) is bounded above by the square root of the second Dirichlet eigenvalue of Ω. We prove some weaker versions of these conjectures in dimension two, as well as their validity for domains asymptotically close to a disk, and also discuss further links between κ(Ω) and the eigenvalues of the Laplacians.
Resumo:
The precision of quasioptical null-balanced bridge instruments for transmission and reflection coefficient measurements at millimeter and submillimeter wavelengths is analyzed. A Jones matrix analysis is used to describe the amount of power reaching the detector as a function of grid angle orientation, sample transmittance/reflectance and phase delay. An analysis is performed of the errors involved in determining the complex transmission and reflection coefficient after taking into account the quantization error in the grid angle and micrometer readings, the transmission or reflection coefficient of the sample, the noise equivalent power of the detector, the source power and the post-detection bandwidth. For a system fitted with a rotating grid with resolution of 0.017 rad and a micrometer quantization error of 1 μm, a 1 mW source, and a detector with a noise equivalent power 5×10−9 W Hz−1/2, the maximum errors at an amplitude transmission or reflection coefficient of 0.5 are below ±0.025.
Resumo:
Myostatin is a potent inhibitor of muscle development. Genetic deletion of myostatin in mice results in muscle mass increase, with muscles often weighing three times their normal values. Contracting muscle transfers tension to skeletal elements through an elaborate connective tissue network. Therefore, the connective tissue of skeletal muscle is an integral component of the contractile apparatus. Here we examine the connective tissue architecture in myostatin null muscle. We show that the hypertrophic muscle has decreased connective tissue content compared with wild-type muscle. Secondly, we show that the hypertrophic muscle fails to show the normal increase in muscle connective tissue content during ageing. Therefore, genetic deletion of myostatin results in an increase in contractile elements but a decrease in connective tissue content. We propose a model based on the contractile profile of muscle fibres that reconciles this apparent incompatible tissue composition phenotype.
Resumo:
Food restriction has a great impact on skeletal muscle mass by inducing muscle protein breakdown to provide substrates for energy production through gluconeogenesis. Genetic models of hyper-muscularity interfere with the normal balance between protein synthesis and breakdown which eventually results in extreme muscle growth. Mutations or deletions in the myostatin gene result in extreme muscle mass. Here we evaluated the impact of food restriction for a period of 5 weeks on skeletal muscle size (i.e., fibre cross-sectional area), fibre type composition and contractile properties (i.e., tetanic and specific force) in myostatin null mice. We found that this hyper-muscular model was more susceptible to catabolic processes than wild type mice. The mechanism of skeletal muscle mass loss was examined and our data shows that the myostatin null mice placed on a low calorie diet maintained the activity of molecules involved in protein synthesis and did not up-regulate the expression of genes pivotal in ubiquitin-mediated protein degradation. However, we did find an increase in the expression of genes associated with autophagy. Surprisingly, the reduction on muscle size was followed by improved tetanic and specific force in the null mice compared to wild type mice. These data provide evidence that food restriction may revert the hyper-muscular phenotype of the myostatin null mouse restoring muscle function.