10 resultados para ECHO AMPLITUDES
em Brock University, Canada
Resumo:
This thesis is intended to contribute to critical discussion of the American male hero in mainstream American war and action films post September 11, 2001 . The thesis investigates how these heroes' behaviour echoes a patriotic, conservative construction of the modern American as created through speeches given by George W. Bush in the wake of the events of September 11, 2001 . The thesis examines the hero in six primary sources: the war films We Were Soldiers, Behind Enemy Lines and The Great Raid and the action films Collateral Damage, Man on Fire and The Punisher. By analyzing the ideological subtext, political content, visual strategies and generic implications of the films, as well as the binary constructions of a selection of Bush speeches, and by reviewing historical representations of American male heroes on film produced in the wake of political events, the thesis concludes that the six films mobilize the USA's conservative viewpoint towards war and military action, and in concert with the speeches, contribute to an ongoing militarization of visual culture. Both systems echo a dangerous ideological fantasy of American history, life and patriotism.
Resumo:
The objective of this study was to examine the association between body
composition and arterial stiffuess in peri-pubescent boys and girls. Differences in arterial
distensibility were measured in 68 children (45 normal weight, 12 overweight, and 11
obese) between the ages of9 to 12 years. Weight classification was based on age and
gender-specific body mass index cut-offs, while pubertal maturation was self-reported
using Tanner staging. Distensibility was determined using two-dimensional, B-Mode
echo Doppler ultrasound to measure changes at the right common carotid artery (CCA)
diameter changes, while carotid pulse pressure (cPP) was measured at the left CCA by
applanation tonometry. One-way ANOV A analysis revealed significant differences
(p<0.001) in all anthropometric measures between the normal weight and overweight
children, as well as the normal weight and obese children. Body stature was only higher
in obese children compared to normal weight children (p<0.01). No significant
differences were found between groups regarding age or Tanner stage. Common carotid
artery distensibility showed a significant difference (p<0.01) between normal weight
children (0.008 ± 0.002 mmHg-1
) compared to obese children (0.005 ± 0.002 mmHg-1
),
with a borderline significant difference between the normal and overweight subjects
(p=0.06). There was no significant effect for gender between males and females across
all independent variables. The strongest determinants of distensibility in children were
cPP (r= -0.52, p
Resumo:
In studies of cognitive processing, the allocation of attention has been consistently linked to subtle, phasic adjustments in autonomic control. Both autonomic control of heart rate and control of the allocation of attention are known to decline with age. It is not known, however, whether characteristic individual differences in autonomic control and the ability to control attention are closely linked. To test this, a measure of parasympathetic function, vagal tone (VT) was computed from cardiac recordings from older and younger adults taken before and during performance of two attentiondemanding tasks - the Eriksen visual flanker task and the source memory task. Both tasks elicited event-related potentials (ERPs) that accompany errors, i.e., error-related negativities (ERNs) and error positivities (Pe's). The ERN is a negative deflection in the ERP signal, time-locked to responses made on incorrect trials, likely generated in the anterior cingulate. It is followed immediately by the Pe, a broad, positive deflection which may reflect conscious awareness of having committed an error. Age-attenuation ofERN amplitude has previously been found in paradigms with simple stimulus-response mappings, such as the flanker task, but has rarely been examined in more complex, conceptual tasks. Until now, there have been no reports of its being investigated in a source monitoring task. Age-attenuation of the ERN component was observed in both tasks. Results also indicated that the ERNs generated in these two tasks were generally comparable for young adults. For older adults, however, the ERN from the source monitoring task was not only shallower, but incorporated more frontal processing, apparently reflecting task demands. The error positivities elicited by 3 the two tasks were not comparable, however, and age-attenuation of the Pe was seen only in the more perceptual flanker task. For younger adults, it was Pe scalp topography that seemed to reflect task demands, being maximal over central parietal areas in the flanker task, but over very frontal areas in the source monitoring task. With respect to vagal tone, in the flanker task, neither the number of errors nor ERP amplitudes were predicted by baseline or on-task vagal tone measures. However, in the more difficult source memory task, lower VT was marginally associated with greater numbers of source memory errors in the older group. Thus, for older adults, relatively low levels of parasympathetic control over cardiac response coincided with poorer source memory discrimination. In both groups, lower levels of baseline VT were associated with larger amplitude ERNs, and smaller amplitude Pe's. Thus, low VT was associated in a conceptual task with a greater "emergency response" to errors, and at the same time, reduced awareness of having made them. The efficiency of an individual's complex cognitive processing was therefore associated with the flexibility of parasympathetic control of heart rate, in response to a cognitively challenging task.
Resumo:
:ofiedian lethal temperatures ( LT50' s ) were determined for rainbow trout, Salmo gairdnerii, acclimated for a minimum of 21 days at 5 c onstant temperatures between 4 and 20 0 C. and 2 diel temperature fluctuations ( sinewave curves of amplitudes ± 4 and ± 7 0 C. about a mean temperature of 12 0 C. ) . Twenty-four-, 48-, and 96-hour LT50 estimates were c alculated f ollowing standard flow-through aquatic bioassay techniques and probi t transformation of mortality data. The phenomenon of delayed thermal mortality was also investigated. Shifts in upper incipient lethal temperature occurred as a result of previous thermal conditioning. It was shown that increases in constant acclimation temperature result in proportional l inear increases in thermal tolerances. The increase i n estimated 96-hour LT50's was approximately 0.13 0 c. X 1 0 C:1 between 8 and 20 0 C. The effect of acclimation to both cyclic temperature regimes was an increase in LT50 to values between the mean and maximum constant equivalent daily temperatures of the cycles. Twenty-four-, 48-, and 96-hour LT50 estimates of both cycles corresponded approximately to the LT50 values of the 16 0 C. c onstant temperature equivalent . This increase i n thermal tolerance was further demonstrated by the delayed thermal mortality experiments . Cycle amplitudes appeared to i nfluence thermal resistance through alterations in initi al mortality since mortality patterns characteristic of base temperature acclimations re-appeared after approximately 68 hours exposure to test temperatures for the 12 + 4 0 C. group, whereas mortality patterns stabilized and remained constant for a period greater than 192 hours with the larger therma l cycle ( 12 + 7 0 C. ). NO s ignificant corre lations between s pecimen weight and time-to-death was apparent. Data are discussed in relation to the establishment of thermal criteria for important commercial and sport fishes , such as the salmonids , as is the question whether previously reported values on lethal temperature s may have been under estimated.
Resumo:
Daytime napping improves well-being and performance for young adults. The benefits of napping in older adults should be investigated because they have fragmented nocturnal sleep, cognitive declines, and more opportunity to nap. In addition, experience with napping might influence the benefits of napping. Study 1 examined the role of experience with napping in young adults. Habitual (n = 23) and non-habitual nappers (n = 16) were randomly assigned to a 20-minute nap or a 20- minute reading condition. Both groups slept the same according to macro architecture. However, microarchitecture showed greater theta, alpha, and beta power during Stage 1, and greater delta, alpha, and sigma power during Stage 2 for habitual nappers, for the most part indicating better sleep. Both groups felt less sleepy after the nap. P2 latency, reflecting information processing, decreased after the nap for habitual nappers, and after the control condition for non-habitual nappers. In sum, both groups who slept felt better, but only the habitual nappers who napped gained a benefit in terms of information processing. Based on this outcome, experience with napping was investigated in Study 2. Study 2 examined the extent to which daytime napping enhanced cognition in older adults, especially frontal lobe function. Cognitive deficits in older adults may be due to sleep loss and age-related decline in brain functioning. Longer naps were expected to provide greater improvement, particularly for older adults, by reducing sleep pressure. Thirty-two adults, aged 24-70 years, participated in a repeated measures dose-response manipulation of sleep pressure. Twenty- and sixty-minute naps were compared to a no-nap condition in three age groups. Mood, subjective sleepiness, reaction time, working memory, 11 novelty detection, and waking electro physiological measures were taken before and after each condition. EEG was also recorded during each nap or rest condition. Napping reduced subjective sleepiness, improved working memory (serial addition / subtraction task), and improved attention (reduced P2 amplitude). Physiological sleepiness (i.e., waking theta power) increased following the control condition, and decreased after the longer nap. Increased beta power after the short nap, and seen with older adults overall, may have reflected increased mental effort. Older adults had longer latencies and smaller amplitudes for several event-related potential components, and higher beta and gamma power. Following the longer nap, gamma power decreased for older adults, but increased for young adults. Beta and gamma power may represent enhanced alertness or mental effort. In addition, Nl amplitude showed that benefits depend on the preceding nap length as well as age. Since the middle group had smaller Nl amplitudes following the short nap and rest condition, it is possible that they needed a longer nap to maintain alertness. Older adults did not show improvements to Nl amplitude following any condition; they may have needed a nap longer than 60 minutes to gain benefits to attention or early information processing. Sleep characteristics were not related to benefits of napping. Experience with napping was also investigated. Subjective data confirmed habitual nappers were happier to nap, while non-habitual nappers were happier to stay awake, reflecting self-identified napping habits. Non-habitual nappers were sleepier after a nap, and had faster brain activity (i.e., heightened vigilance) at sleep onset. These reasons may explain why non-habitual nappers choose not to nap.
Resumo:
Event-related potentials were recorded from 10-year-old children and young adults in order to examine the developmental dififerences in two frontal lobe functions: detection of novel stimuli during an auditory novelty oddball task, and error detection during a visual flanker task. All participants showed a parietally-maximal P3 in response to auditory stimuli. In children, novel stimuli generated higher P3 amplitudes at the frontal site compared with target stimuli, whereas target stimuli generated higher P3 amplitudes at the parietal site compared with novel stimuli. Adults, however, had higher P3 amplitude to novel tones compared with target tones at each site. Children also had greater P3 amplitude at more parietal sites than adults during the novelty oddball and flanker tasks. Furthermore, children and adults did not show a significant reduction in P3 amplitude from the first to second novel stimulus presentation. No age differences were found with respect to P3 latency to novel and target stimuli. These findings suggest that the detection of novel and target stimuli is mature in 10-year-olds. Error trials typically elicit a negative ERP deflection (the ERN) with a frontal-central scalp distribution that may reflect response monitoring. There is also evidence of a positive ERP peak (the Pe) with a posterior scalp distribution which may reflect subjective recognition of a response. Both children and adults showed an ERN and Pe maximal at frontal-central sites. Children committed more errors, had smaller ERN across sites, and had a larger Pe at the parietal site than adults. This suggests that response monitoring is still immature in 10-year-olds whereas recognition of and emotional responses to errors may be similar in children and adults.
Resumo:
Imaging studies have shown reduced frontal lobe resources following total sleep deprivation (TSD). The anterior cingulate cortex (ACC) in the frontal region plays a role in performance monitoring and cognitive control; both error detection and response inhibition are impaired following sleep loss. Event-related potentials (ERPs) are an electrophysiological tool used to index the brain's response to stimuli and information processing. In the Flanker task, the error-related negativity (ERN) and error positivity (Pe) ERPs are elicited after erroneous button presses. In a Go/NoGo task, NoGo-N2 and NoGo-P3 ERPs are elicited during high conflict stimulus processing. Research investigating the impact of sleep loss on ERPs during performance monitoring is equivocal, possibly due to task differences, sample size differences and varying degrees of sleep loss. Based on the effects of sleep loss on frontal function and prior research, it was expected that the sleep deprivation group would have lower accuracy, slower reaction time and impaired remediation on performance monitoring tasks, along with attenuated and delayed stimulus- and response-locked ERPs. In the current study, 49 young adults (24 male) were screened to be healthy good sleepers and then randomly assigned to a sleep deprived (n = 24) or rested control (n = 25) group. Participants slept in the laboratory on a baseline night, followed by a second night of sleep or wake. Flanker and Go/NoGo tasks were administered in a battery at 1O:30am (i.e., 27 hours awake for the sleep deprivation group) to measure performance monitoring. On the Flanker task, the sleep deprivation group was significantly slower than controls (p's <.05), but groups did not differ on accuracy. No group differences were observed in post-error slowing, but a trend was observed for less remedial accuracy in the sleep deprived group compared to controls (p = .09), suggesting impairment in the ability to take remedial action following TSD. Delayed P300s were observed in the sleep deprived group on congruent and incongruent Flanker trials combined (p = .001). On the Go/NoGo task, the hit rate (i.e., Go accuracy) was significantly lower in the sleep deprived group compared to controls (p <.001), but no differences were found on false alarm rates (i.e., NoGo Accuracy). For the sleep deprived group, the Go-P3 was significantly smaller (p = .045) and there was a trend for a smaller NoGo-N2 compared to controls (p = .08). The ERN amplitude was reduced in the TSD group compared to controls in both the Flanker and Go/NoGo tasks. Error rate was significantly correlated with the amplitude of response-locked ERNs in control (r = -.55, p=.005) and sleep deprived groups (r = -.46, p = .021); error rate was also correlated with Pe amplitude in controls (r = .46, p=.022) and a trend was found in the sleep deprived participants (r = .39, p =. 052). An exploratory analysis showed significantly larger Pe mean amplitudes (p = .025) in the sleep deprived group compared to controls for participants who made more than 40+ errors on the Flanker task. Altered stimulus processing as indexed by delayed P3 latency during the Flanker task and smaller amplitude Go-P3s during the Go/NoGo task indicate impairment in stimulus evaluation and / or context updating during frontal lobe tasks. ERN and NoGoN2 reductions in the sleep deprived group confirm impairments in the monitoring system. These data add to a body of evidence showing that the frontal brain region is particularly vulnerable to sleep loss. Understanding the neural basis of these deficits in performance monitoring abilities is particularly important for our increasingly sleep deprived society and for safety and productivity in situations like driving and sustained operations.
Resumo:
Donald J. P. Ziraldo, C.M., BSc., LLD was born in St. Catharines, Ontario on October 13, 1948 to Fredrick and Irma (Schiratti) Ziraldo. He graduated Denis Morris High School in St. Catharines in 1967, and received his B.Sc. in Agriculture at the University of Guelph in 1971. In 1974, Ziraldo was running Ziraldo Nurseries when he met Austrian born schoolteacher, chemist and winemaker Karl J. Kaiser. They realized that there was a gap in the premium varietal wine market and decided to plant a premium traditional European variety of grape vine species, the Vitis vinifera. This was an innovation in the Niagara region because the current wine producers were not using premium European grapes at the time. Ziraldo and Kaiser founded and then formally incorporated Inniskillin Wines Inc. in Niagara-on-the-Lake, Ontario on July 31, 1975. Ziraldo successfully lobbied General George Kitching, CEO of the LCBO, for a winery license. In 1975, Kitching granted him a winery license, the first in Ontario since Prohibition ended. From the beginning, there was a division of labour where Kaiser focused on the winemaking and Ziraldo focused on the marketing and promotion of the wines. Ziraldo also became president of the company. Ziraldo and Kaiser worked on improving their winemaking techniques and promoting their products and company. Ziraldo has been called ‘one of the founding fathers of the Canadian wine industry’, and it is widely acknowledged that both men played a large role in the success and growth of the Canadian wine industry. Together they pioneered the estate winery movement in Canada. A major turning point Inniskillin came in 1984 when Karl Kaiser successfully harvested the first Icewine crop from frozen grapes on the vine and bottled Eiswein Vidal (Icewine). In 1990, Inniskillin received worldwide recognition for this Icewine when their 1989 Vidal Icewine won the most prestigious award in the wine world, the Grand Prix d’Honneur, given at Vinexpo in France. This victory has been called ‘the award heard round the world’ and it launched Inniskillin into the international wine arena. At the same time, this helped lift the profile of Canadian wines in general. Inniskillin not only became Canada’s leading producer of Icewine, but it also became known for producing ‘one of the world’s great wines’. After the 1990 award, Ziraldo began a major public relations campaign to promote Inniskillin and build Icewine into a worldwide brand. He travelled broadly every year to promote the brand and products and networked extensively with politicians, celebrities, chefs, sommeliers, etc. To ensure worldwide and long-term success, Ziraldo introduced Icewine to Asia and the United States which were new markets. He developed a new Icewine glass with George Riedel. Tony Aspler has called Ziraldo ‘Canada’s Wine Ambassador’. Ziraldo was President of Inniskillin Wines Inc. (Niagara) from 1975 to 2006. In 1992, Inniskillin merged with Cartier Wines, and in 1993 Cartier Inniskillin Vintners Inc. merged with T.G. Bright & Co. Limited, forming the new company Vincor International Inc. Inniskillin wines was now a subsidiary of Vincor. Ziraldo became a Director at Vincor International Inc. from 1993 to 2004. From 1989 to the mid 1990s, Ziraldo also became President of Inniskillin Napa, in Napa Valley, California. Inniskillin purchased Napa Valley vineyards and produced wines under the Terra label. In 1994, Ziraldo set up a subsidiary estate winery of Inniskillin in Oliver, British Columbia which was called Inniskillin Okanagan Vineyards Inc. He became President of the winery. This started as a partnership between Inniskillin and the local Inkameep Indian Band in the Okanagan. In 2006, Ziraldo left Inniskillin and since that time he has been involved in other Icewine related ventures such as running Ziraldo Estate Winery and producing Ziraldo Riesling Icewine 2007. He also is in partnership with the Niagara based Equifera Estate Winery to produce Equifera Icewine. His most recent projects include planting Picolit grapes in his parent’s hometown, in a project called Picolit Di Fagagna and becoming Managing Director of the Senhora Do Convento Port Winery in Portugal. Donald Ziraldo was instrumental in the creation of the Vintners Quality Alliance (VQA) in Ontario and was its founding Chair from 1988-1995. The VQA was established as a regulatory and appellation system which secured the quality and origin of Canadian wines made under this system. The VQA designation and bottle label gave the consumer confidence that the wines they were purchasing were 100% local products. The VQA system was set up first in Ontario and then in British Columbia.
Resumo:
Two time-resolved EPR techniques, have been used to study the light induced electron transfer(ET) in Type I photosynthetic reaction centers(RCs). First, pulsed EPR was used to compare PsaA-M688H and PsaB-M668H mutants of Chlamydomonas reinhardtii and Synechosystis sp. PCC 6803.The out-of-phase echo modulation curves combined with other EPR and optical data show that the effect of the mutations is species dependent. Second, transient and pulsed EPR data are presented which show that PsaA-A660N and PsaB-A640N mutations in C. reinhardtii alter the relative quantum yield of ET in the A- and B-branches of PS I. Third, transient EPR studies on RCs from Heliobacillus mobilis that have been exposed to oxygen show partial inhibition of ET. In the RCs in which ET still occurs, the ET kinetics and EPR spectra show evidence of oxidation of some but not all of the, BChl g and BChl g' to Chl a.
Resumo:
Self-regulation is considered a powerful predictor of behavioral and mental health outcomes during adolescence and emerging adulthood. In this dissertation I address some electrophysiological and genetic correlates of this important skill set in a series of four studies. Across all studies event-related potentials (ERPs) were recorded as participants responded to tones presented in attended and unattended channels in an auditory selective attention task. In Study 1, examining these ERPs in relation to parental reports on the Behavior Rating Inventory of Executive Function (BRIEF) revealed that an early frontal positivity (EFP) elicited by to-be-ignored/unattended tones was larger in those with poorer self-regulation. As is traditionally found, N1 amplitudes were more negative for the to-be-attended rather than unattended tones. Additionally, N1 latencies to unattended tones correlated with parent-ratings on the BRIEF, where shorter latencies predicted better self-regulation. In Study 2 I tested a model of the associations between selfregulation scores and allelic variations in monoamine neurotransmitter genes, and their concurrent links to ERP markers of attentional control. Allelic variations in dopaminerelated genes predicted both my ERP markers and self-regulatory variables, and played a moderating role in the association between the two. In Study 3 I examined whether training in Integra Mindfulness Martial Arts, an intervention program which trains elements of self-regulation, would lead to improvement in ERP markers of attentional control and parent-report BRIEF scores in a group of adolescents with self-regulatory difficulties. I found that those in the treatment group amplified their processing of attended relative to unattended stimuli over time, and reduced their levels of problematic behaviour whereas those in the waitlist control group showed little to no change on both of these metrics. In Study 4 I examined potential associations between self-regulation and attentional control in a group of emerging adults. Both event-related spectral perturbations (ERSPs) and intertrial coherence (ITC) in the alpha and theta range predicted individual differences in self-regulation. Across the four studies I was able to conclude that real-world self-regulation is indeed associated with the neural markers of attentional control. Targeted interventions focusing on attentional control may improve self-regulation in those experiencing difficulties in this regard.