Physical modelling of dynamic recrystallization of the cyclic peak type

Dynamic re-crystallization is a process of discontinuous crystallization during hot-working. This is a very interesting process that has been modeled in several ways. In this project I’ve tried to model the birth, increment, and extinction of crystallites by using only the Avrami equation. The Avrami equation is quite simple to write. It describes the occurrence of newborn crystallites during nucleation and growth processes. The equation establishes that the ratio of the real volume and the extended volume is equal to the fraction of free space. We will get more in detail in the chapter 2. While in a crystallization process the free space is simply the uncrystallized space, in re- crystallization processes it must be redefined as the space available for growth, regardless if it was previously crystallized. The project consisted in write the adequate model and a code to check its validity. I then made several tests with the final code, with variations on each parameters, and I gathered it in the chapter 3

The influence of proficiency and language combination on bilingual lexical access

The present study examines the nature of bilingual lexical access using category fluency across five language combinations using 109 healthy speakers of Hindi-English, Kannada-English, Mandarin-English, Spanish-English, and Turkish-English. Participants completed a category fluency task in each of their languages in three main categories (animals, clothing, food), each with two subcategories, as well as a language use questionnaire assessing their proficiency in each of their languages. Multivariate analyses of variance revealed that the average number of correct items named in the category fluency task across the three main categories varied across the different groups for English items only. A series of repeated-measures analyses of covariance revealed that the exposure component that had been extracted from the language use questionnaire using a principal component analysis significantly affected the average number of items named across the three main categories. When the effect of exposure was controlled, the effect of language combination was no longer significant. A regression analysis showed that the relative amount of exposure participants had to each of their languages predicted participants’ relative performance in each language. Additional multivariate analyses of variance found significant differences in the number of correct items named in each main category and subcategory in both English and participants’ other language based on language combination. Overall, these results demonstrate the effects of particular language combinations on bilingual lexical access and provide important insights into the role of proficiency on access

MS 093 Guide to Marvin A. Kastenbaum, Ph.D., Papers (1950-1997)

The Marvin A. Kastenbaum, PhD, papers, MS 93, 1950-1997, contains materials related to the Atomic Bomb Casualty Commission (ABCC), including audio-visual materials, photographs, artifacts, personal cards, clippings, and statistical analyses compilied by the ABCC. Kastenbaum worked for 17 months as a statistician with the ABCC. Kastenbaum\u27s first contribution to the archive in March 1994 was a set of photographs of ABCC employees. See more at MS 093

Discrete Pearson distributions

These distributions are generated by a first order recursive scheme which equates the ratio of successive probabilities to the ratio of two corresponding quadratics. The use of a linearized form of this model will produce equations in the unknowns matched by an appropriate set of moments (assumed to exist). Given the moments we may find valid solutions. These are two cases; (1) distributions defined on the non-negative integers (finite or infinite) and (2) distributions defined on negative integers as well. For (1), given the first four moments, it is possible to set this up as equations of finite or infinite degree in the probability of a zero occurrence, the sth component being a product of s ratios of linear forms in this probability in general. For (2) the equation for the zero probability is purely linear but may involve slowly converging series; here a particular case is the discrete normal. Regions of validity are being studied. 11 refs

Alternative methods to evaluate the protective ability of sunscreen against photo-genotoxicity

Numerous epidemiological investigations show that sunlight is carcinogenic to humans and that the use of sunscreen may be effective in decreasing the risk of skin cancer. The biological activity of a sunscreen is evaluated by its ability to protect human skin from erythema as represented by a Sun Protection Factor (SPF). We propose that the sunscreen's protective effect against sunlight-induced genotoxicity, including mutation, should also be taken into account. In this study we examined the protective ability of sunscreens against natural sunlight and UV-induced genotoxicity in Drosophila somatic cells. We prepared three kinds of sunscreen samples, each with an SPF value of 20, 40 or 60 and compared their protective activities with commercial sunscreens. When a sunscreen of SPF 20, 40 or 60 was pasted on the plastic cover of a petri dish in which Drosophila larvae were exposed to the sun or UV lamps, genotoxicity decreased as the SPF of the sunscreen increased, relative to levels of genotoxicity observed in samples without sunscreen. However, the protective abilities of sunscreens were unexpectedly not so different from each other. To reveal the relationship between the protective activity of sunscreen and the wavelength of light with which larvae were irradiated through the sunscreen, we measured the transmittance of light through the petri dish cover on which the sunscreen was pasted. Effective protection was demonstrated by removing components of light whose wavelengths were below 315 nm. We suggest, that the measurement of anti-genotoxic activity and the determination of the wavelengths of light transmitted through the sunscreen should be an alternative method for evaluating the effectiveness of a sunscreen.</p

Thoughts of Death Modulate Psychophysical and Cortical Responses to Threatening Stimuli

Existential social psychology studies show that awareness of one's eventual death profoundly influences human cognition and behaviour by inducing defensive reactions against end-of-life related anxiety. Much less is known about the impact of reminders of mortality on brain activity. Therefore we explored whether reminders of mortality influence subjective ratings of intensity and threat of auditory and painful thermal stimuli and the associated electroencephalographic activity. Moreover, we explored whether personality and demographics modulate psychophysical and neural changes related to mortality salience (MS). Following MS induction, a specific increase in ratings of intensity and threat was found for both nociceptive and auditory stimuli. While MS did not have any specific effect on nociceptive and auditory evoked potentials, larger amplitude of theta oscillatory activity related to thermal nociceptive activity was found after thoughts of death were induced. MS thus exerted a top-down modulation on theta electroencephalographic oscillatory amplitude, specifically for brain activity triggered by painful thermal stimuli. This effect was higher in participants reporting higher threat perception, suggesting that inducing a death-related mind-set may have an influence on body-defence related somatosensory representations