The tumor suppressor p53 acts as a master transcription factor that controls hundreds of effecter genes in response to various cellular stresses. The flexibility of p53 to regulate its target genes with distinct functions (growth arrest, DNA repair, apoptosis etc.) is largely conferred by extensive and dynamic posttranslational modifications of the protein, including phosphorylation, acetylation, methylation, ubiquitination, sumoylation, neddylation and ADP-ribosylation. Recent evidence suggests that acetylation is indispensable for p53 activation. A major regulator of p53 acetylation, and hence p53 function, is a group of Class III histone deacetylases known as Sirtuins (SIRTs), that utilize nicotinamide adenine dinucleotide (NAD+) as substrate to catalyze the removal of acetyl groups from p53, resulting in the “silencing” of p53 activity. In an effort to determine whether a feedback loop exists whereby p53 is involved in the regulation of NAD+ metabolism, nicotinamide adenylyltransferase 2 (Nmnat2), a key NAD+ synthetase, was identified to be a novel target gene of p53, from which two transcript variants are expressed in human (TV1 and TV2). Two putative p53 response elements within the first intronic region of human Nmnat2 gene were also identified that can actively drive the expression of luciferase reporter gene in a p53-dependent manner. Most importantly, data suggests that Nmnat2, like SIRTs, is involved in the regulation of p53-mediated apoptosis and protein acetylation upon DNA damage. Furthermore, Nmnat2 isoforms exert opposite functions on SIRT-mediated deacetylation of p53. Specifically, ectopic expression of Nmnat2 TV2 isoform promotes p53 acetylation after DNA damage, whereas ectopic expression of Nmnat2-TV1 isoform suppresses it. Manipulation of SIRT activities by either RNA interference or specific inhibitors modifies p53 acetylation status the same way Nmnat2-TV2 isoform does. Collectively, the results suggest the existence of a p53-Nmnat2 feedback loop, whereby p53 can regulate its own activity positively or negatively, depending on the nature and extent of DNA damage.

No description available.

No description available.

No description available.

The goal of the current research was to improve on previous studies by more directly examining the relationship between perfectionism and actual procrastination behaviour. In Study 1, participants (N = 167) were given five minutes to prepare for a verbal analogy test during which time they could complete practice materials or play a computer game. After the first test, participants were randomly assigned to receive positive feedback, negative feedback, or no feedback. They then had a second chance to study or play the computer game before they completed another verbal analogy test. Adaptive perfectionism was a significant predictor of less procrastination behaviour on the initial test although feedback on the first test did not change the subsequent behaviour of adaptive perfectionists. Maladaptive perfectionism was not a significant predictor of procrastination behaviour on the initial task. However, for women who were higher in maladaptive perfectionism, the more upset they were from receiving negative feedback on the first task, the more they increased their procrastination on the second task. The purpose of Study 2 was to examine two potential mechanisms, low performance expectations or mood repair, which may have been responsible for the increase in procrastination behaviour seen in women who were higher in maladaptive perfectionism and upset about receiving negative feedback. Participants (N = 138) all received negative feedback on the first test, which was followed by an optimism prime, positive mood prime, or neutral prime. Participants then were given a second chance to study or play the computer game before they completed another verbal analogy test. The positive mood prime did not have a significant effect on procrastination behaviour. Among women who were lower in adaptive perfectionism, the optimism prime resulted in a decrease in procrastination behaviour for women higher in maladaptive perfectionism and an increase in procrastination behaviour for women lower in maladaptive perfectionism. These findings are discussed in terms of their relevance for the academic outcomes of adaptive and maladaptive perfectionists. / Thesis (Master, Psychology) -- Queen's University, 2011-09-27 17:57:45.647

Formativ bedömning är den process där bedömningar används för att fatta beslut och forma undervisningen. Att som lärare använda formativ bedömning i praktiken har visat sig ha goda effekter på elevers lärande och resultat. Syftet med studien är att få fördjupad förståelse för elevers erfarenheter av de metoder som används inom formativ bedömning och elevernas förmåga att uppfatta och värdera sitt eget lärande i matematikundervisningen. Jag vill undersöka vilka elevernas erfarenheter är av metoderna som baseras på de nyckelstrategier som finns inom formativ bedömning samt jämföra om det är någon skillnad på grupper som arbetat med lärare som utbildats i formativ bedömning och de elever som inte arbetat med en lärare som har fått samma utbildning inom formativ bedömning. För att göra detta kommer jag använda mig av en enkätundersökning. Resultaten i min undersökning visade att elever som undervisas av lärare med utbildning i formativ bedömning har större erfarenhet av metoderna inom nyckelstrategierna. Resultaten visade också att dessa elever i större utsträckning kunde värdera sitt lärande och undervisningen på ett sätt som gynnar deras utveckling.

No description available.

No description available.

No description available.

Despite the shift from dualism to materialism, philosophy of mind and cognitive science still face the challenge of explaining the interaction of the physical and the mental. The language of thought hypothesis, combined with advances in computing offers a promising explanation of the aforementioned interaction by capitalizing on the parallels between the syntax and semantics of language. Unfortunately, the language of thought hypothesis is vulnerable to arguments and objections that stem from syntactic ambiguity, semantic poverty, and semantic causation, all of which stand in the way of creating a working theory of mind. I will claim that these problems can be avoided by incorporating feedback to regulate the semantic content in chains of thoughts. The regulation of semantic content would allow the operations performed by the psychological machinery responsible for the process of thinking to be causally sensitive to the semantic content of thoughts. The causal influence of the feedback would be heuristic, rather than algorithmic, avoiding the explanatory pitfalls traditionally encountered in attempts to integrate semantic content into strict, syntax manipulating mechanisms. The inclusion of consciousness feedback also answers a solipsistic worry, the syntactic zombie, as well as fitting more closely with our experience of cognition.