PHYTOCHROME KINASE SUBSTRATE4 modulates phytochrome-mediated control of hypocotyl growth orientation

Gravity and light are major factors shaping plant growth. Light perceived by phytochromes leads to seedling deetiolation, which includes the deviation from vertical hypocotyl growth and promotes hypocotyl phototropism. These light responses enhance survival of young seedlings during their emergence from the soil. The PHYTOCHROME KINASE SUBSTRATE (PKS) family is composed of four members in Arabidopsis (Arabidopsis thaliana): PKS1 to PKS4. Here we show that PKS4 is a negative regulator of both phytochrome A- and B-mediated inhibition of hypocotyl growth and promotion of cotyledon unfolding. Most prominently, pks4 mutants show abnormal phytochrome-modulated hypocotyl growth orientation. In dark-grown seedlings hypocotyls change from the original orientation defined by seed position to the upright orientation defined by gravity and light reduces the magnitude of this shift. In older seedlings with the hypocotyls already oriented by gravity, light promotes the deviation from vertical orientation. Based on the characterization of pks4 mutants we propose that PKS4 inhibits changes in growth orientation under red or far-red light. Our data suggest that in these light conditions PKS4 acts as an inhibitor of asymmetric growth. This hypothesis is supported by the phenotype of PKS4 overexpressers. Together with previous findings, these results indicate that the PKS family plays important functions during light-regulated tropic growth responses

Construire sa vie (Life designing): Un paradigme pour l'orientation au 21e siècle

La nouvelle organisation sociale du travail du début du 21e siècle pose une série de questions et lance de nombreux défis aux spécialistes de l'accompagnement en orientation professionnelle. Compte tenu de la mondialisation du conseil en orientation, c'est dans un cadre international que nous avons décidé d'aborder ces questions, puis de formuler des réponses potentiellement innovantes. Cette approche permet d'éviter les difficultés que soulève la création de modèles et de méthodes dans un pays donné en tentant ensuite de les exporter dans d'autres, où ils doivent être adaptés pour être utilisés. Cet article présente le premier résultat tangible de cette collaboration : un modèle et des méthodes d'accompagnement des personnes. Le modèle « Construire sa vie », destiné à des interventions d'accompagnement en orientation se fonde sur cinq présupposés concernant les personnes et leur vie professionnelle : des possibilités liées aux contextes, des processus dynamiques, une progression non linéaire, des perspectives multiples et des configurations individuelles. En partant de ces présupposés, nous avons bâti un modèle en contexte, se réclamant de l'épistémologie du constructionnisme social, reconnaissant en particulier que les connaissances et l'identité d'un individu sont le produit d'interactions sociales et que le sens est co-construit, via la médiation du discours. Le cadre général « construire sa vie » s'appuie sur les théories de la construction de soi (Guichard, 2005) et de la construction des parcours professionnels (Savickas, 2005), qui décrivent les conduites d'orientation et leurs développements. Ce cadre concerne toute la vie, il est holiste, tient compte des contextes et est préventif.

Orientation of Non-Native 2-Monosubstituted and 2,3-Disubstituted 1,4-Naphthoquinones in the A1 binding site of PSI and the effect on the rate of electron transfer : an electron paramagnetic resonance spectroscopy study

The proce-ss ofoxygenic photosynthesis is vital to life on Earth. the central event in photosynthesis is light induced electron transfer that converts light into energy for growth. Ofparticular significance is the membrane bound multisubunit protein known as Photosystem I (PSI). PSI is a reaction centre that is responsible for the transfer of electrons across the membrane to reduce NADP+ to NADPH. The recent publication ofa high resolution X-ray structure of PSI has shown new information about the structure, in particular the electron transfer cofactors, which allows us to study it in more detail. In PSI, the secondary acceptor is crucial for forward electron transfer. In this thesis, the effect of removing the native acceptor phylloquinone and replacing it with a series of structurally related quinones was investigated via transient electron paramagnetic resonance (EPR) experiments. The orientation of non native quinones in the binding site and their ability to function in the electron transfer process was determined. It was found that PSI will readily accept alkyl naphthoquinones and anthraquinone. Q band EPR experiments revealed that the non-native quinones are incorporated into the binding site with the same orientation of the headgroup as in the native system. X band EPR spectra and deuteration experiments indicate that monosubstituted naphthoquinones are bound to the Al site with their side group in the position occupied by the methyl group in native PSI (meta to the hydrogen bonded carbonyl oxygen). X band EPR experiments show that 2, 3- disubstituted methyl naphthoquinones are also incorporated into the Al site in the same orientation as phylloquinone, even with the presence of a halogen- or sulfur-containing side chain in the position normally occupied by the phytyl tail ofphylloquinone. The exception to this is 2-bromo-3-methyl --.- _. -. - -- - - 4 _._ _ _ - _ _ naphthoquinone which has a poorly resolved spectrum, making determination of the orientation difficuh. All of the non-native quinones studied act as efficient electron acceptors. However, forward electron transfer past the quinone could only be demonstrated for anthraquinone, which has a more negative midpoint potential than phylloquinone. In the case of anthraquinone, an increased rate of forward electron transfer compared to native PSI was found. From these results we can conclude that the rate ofelectron transfer from Al to Fx in native PSI lies in the normal region ofthe Marcus Curve.

Pigment orientation changes detected by low temperature linear dichroism spectroscopy: cold-hardening transition in phycobilisome-containing organisms

Low temperature (77K) linear dichroism spectroscopy was used to characterize pigment orientation changes accompanying the light state transition in the cyanobacterium, Synechococcus sp. pee 6301, and cold-hardening in winter rye (Secale cereale L. cv. Puma). Samples were oriented for spectroscopy using the gel squeezing method (Abdourakhmanov et aI., 1979) and brought to 77K in liquid nitrogen. The linear dichroism (LD) spectra of Synechococcus 6301 phycobilisome/thylakoid membrane fragments cross-linked in light state 1 and light state 2 with glutaraldehyde showed differences in both chlorophyll a and phycobilin orientation. A decrease in the relative amplitude of the 681nm chlorophyll a positive LD peak was observed in membrane fragments in state 2. Reorientation of the phycobilisome (PBS) during the transition to state 2 resulted in an increase in core allophycocyanin absorption parallel to the membrane, and a decrease in rod phycocyanin parallel absorption. This result supports the "spillover" and "PBS detachment" models of the light state transition in PBS-containing organisms, but not the "mobile PBS" model. A model was proposed for PBS reorientation upon transition to state 2, consisting of a tilt in the antenna complex with respect to the membrane plane. Linear dichroism spectra of PBS/thylakoid fragments from the red alga, Porphyridium cruentum, grown in green light (containing relatively more PSI) and red light (containing relatively more PSll) were compared to identify chlorophyll a absorption bands associated with each photosystem. Spectra from red light - grown samples had a larger positive LD signal on the short wavelength side of the 686nm chlorophyll a peak than those from green light - grown fragments. These results support the identification of the difference in linear dichroism seen at 681nm in Synechococcus spectra as a reorientation of PSll chromophores. Linear dichroism spectra were taken of thylakoid membranes isolated from winter rye grown at 20°C (non-hardened) and 5°C (cold-hardened). Differences were seen in the orientation of chlorophyll b relative to chlorophyll a. An increase in parallel absorption was identified at the long-wavelength chlorophyll a absorption peak, along with a decrease in parallel absorption from chlorophyll b chromophores. The same changes in relative pigment orientation were seen in the LD of isolated hardened and non-hardened light-harvesting antenna complexes (LHCII). It was concluded that orientational differences in LHCII pigments were responsible for thylakoid LD differences. Changes in pigment orientation, along with differences observed in long-wavelength absorption and in the overall magnitude of LD in hardened and non-hardened complexes, could be explained by the higher LHCII monomer:oligomer ratio in hardened rye (Huner et ai., 1987) if differences in this ratio affect differential light scattering properties, or fluctuation of chromophore orientation in the isolated LHCII sample.

Developing a numerical inverse-theory-based extraction of orientation-dependent relaxation rates from partially- relaxed spectra

Second-rank tensor interactions, such as quadrupolar interactions between the spin- 1 deuterium nuclei and the electric field gradients created by chemical bonds, are affected by rapid random molecular motions that modulate the orientation of the molecule with respect to the external magnetic field. In biological and model membrane systems, where a distribution of dynamically averaged anisotropies (quadrupolar splittings, chemical shift anisotropies, etc.) is present and where, in addition, various parts of the sample may undergo a partial magnetic alignment, the numerical analysis of the resulting Nuclear Magnetic Resonance (NMR) spectra is a mathematically ill-posed problem. However, numerical methods (de-Pakeing, Tikhonov regularization) exist that allow for a simultaneous determination of both the anisotropy and orientational distributions. An additional complication arises when relaxation is taken into account. This work presents a method of obtaining the orientation dependence of the relaxation rates that can be used for the analysis of the molecular motions on a broad range of time scales. An arbitrary set of exponential decay rates is described by a three-term truncated Legendre polynomial expansion in the orientation dependence, as appropriate for a second-rank tensor interaction, and a linear approximation to the individual decay rates is made. Thus a severe numerical instability caused by the presence of noise in the experimental data is avoided. At the same time, enough flexibility in the inversion algorithm is retained to achieve a meaningful mapping from raw experimental data to a set of intermediate, model-free

Self concept, acculturation, and fashion orientation

The research begins with a discussion of the worldwide and the Canadian market. The research profiles the examination of the relationship between a person's self concept (as defined by Malhotra) and fashion orientation (as defined by Gutman and Mills), and to understand how these factors are influenced by acculturation, focusing in-depth on their managerial implications. To study these relationships; a random sample of 196 ChineseCanadian female university students living in Canada was given a survey based on Malhotra's self-concept scale, and the SLASIA acculturation scale. Based on multiple regression analysis, findings suggest that the adoption of language and social interaction dimensions of acculturation constructs have significant effects on the relationship between self concept and fashion orientation. This research contributes significantly to both marketing theory and practice. Theoretically, this research develops new insights on the dimensionality of fashion orientation, identifies various moderating effects of acculturation on the relationship of self concept and fashion orientation dimensions, and provides a framework to examine these effects, where results can be generalized across different culture. Practically, marketers can use available findings to improve their understanding of the fashion needs of Chinese-Canadian consumers, and target them based on these findings. The findings provide valuable implications for companies to formulate their fashion marketing strategies for enhance fashion orientation in terms of different dimensions, based on different levels of acculturation.

Investigation of the Relationship between Sexual Orientation and Objective Height, along with Predictors of Height Distortion

Studies that have used mostly self-reported height have found that men with a same-sex orientation and women with an other-sex orientation are shorter, on average, than men with an other-sex orientation and women with a same-sex orientation, respectively. This thesis examined whether an objective height difference exists or whether a psychosocial account (e.g., distortion of self-reports) may explain these putative height differences. Also, this thesis examined whether certain individual differences (e.g, gender roles and socially desirable responding) predict height distortion. Eight hundred and thirteen participants, recruited at Brock University, the Niagara Community and through surrounding LGBT events, completed self-reported height, measures of gender roles and socially desirable responding, and had their height measured. Using hierarchical linear regressions, it was found that Same-Sex/Both-Sex Oriented men were shorter, on average, than predominantly Other-Sex Oriented men; however, there was no difference in objective height between Same-Sex/Both-Sex Oriented women and predominantly Other-Sex Oriented women. These findings contribute to existing biological theories of men's sexual orientation development and do not contribute to biological theories of women's sexual orientation development. Height distortion was not related to sexual orientation and only marginally related to sex. Predictors of height distortion were Impression Management, in both men and women, and Unmitigated Agency, in men. These findings highlight the complexity of sexual orientation development in men and women. These findings also highlight the role of certain psychosocial factors in how people perceive their bodies and/or how they want their bodies to be perceived by others.

The Impact of Personal Trainer’s Leadership Style on Self-Presentational Concerns, Enjoyment, Task Self-Efficacy and Intention to Exercise in an Introductory Weight Training Orientation

The purpose of the present study was to examine two leadership styles of personal trainers (bland versus enriched) to evaluate their effects on exercise-related outcomes. Participants were 103 university women with no previous experience weight training. Participants were randomly assigned to one of the two leadership style conditions. They completed primary measures prior to being introduced to the personal trainer. Next, participants completed an introductory weight training session, followed by post-manipulation measures. The leadership styles were successfully manipulated. Participants in the enriched leadership style condition reported significantly higher levels of enjoyment and intention to exercise. Participants in the bland leadership style condition reported significantly higher levels of social anxiety; no differences were found for task self-efficacy, self-presentational efficacy, social physique anxiety, or handgrip performance between groups. Thus, an enriched leadership style of personal trainers can increase positive psychological outcomes.

The Impact of Directed Mirror Focus and Technique Cues on Psychological, Cognitive and Emotional Exercise Correlates in an Introductory Weight Training Orientation

The purpose of the study was to investigate whether teaching inactive and low active women to use mirrors for form and technique purposes could lessen the negative impact of mirrors on self-presentational concerns, affect, and self-efficacy. Eligible women (N = 82) underwent a one-on-one weight training orientation with a personal trainer. Participants were randomized into one of four experimental groups, each unique in the type of feedback (general or technique-specific) and the degree of focus on the mirror for technique reinforcement. Questionnaires assessed study outcomes pre- and post-orientation. Results indicated groups did not significantly differ on any post-condition variables, when controlling for pre-condition values (all p’s >.05). All groups showed outcome improvements following the orientation. This suggests that during a complex task, a personal trainer who emphasizes form and technique can facilitate improvements to psychological outcomes in novice exercisers, independent of the presence of mirrors or directional cues provided.

QUANTIFICATION AND EXTRACTION OF SURFACE FEATURES FROM DIGITAL TERRAIN MODELS

Digital Terrain Models (DTMs) are important in geology and geomorphology, since elevation data contains a lot of information pertaining to geomorphological processes that influence the topography. The first derivative of topography is attitude; the second is curvature. GIS tools were developed for derivation of strike, dip, curvature and curvature orientation from Digital Elevation Models (DEMs). A method for displaying both strike and dip simultaneously as colour-coded visualization (AVA) was implemented. A plug-in for calculating strike and dip via Least Squares Regression was created first using VB.NET. Further research produced a more computationally efficient solution, convolution filtering, which was implemented as Python scripts. These scripts were also used for calculation of curvature and curvature orientation. The application of these tools was demonstrated by performing morphometric studies on datasets from Earth and Mars. The tools show promise, however more work is needed to explore their full potential and possible uses.

The Trouble with Inversion: an Examination of Science Sexual Orientation

Although some are excited about the possibility of using current scientific research into the biological causes of sexual orientation to ground rights claims, I argue that basing rights claims on this research is unwise because this research, specifically the hormonal, genetic, and structural research, is organized around the inversion assumption, a conceptual scheme within which some aspect of the biology of gay men and lesbians is thought to be inverted along sex lines.While there are many reasons to worry about the use of the inversion assumption, I focus on problems that arise from a further set of claims that must be assumed in order to make the use of the inversion assumption coherent. This further set of assumptions includes the claims (1) that heterosexuality is the standard state and that (2) this standard state is sexually-dimorphic and (3) deterministic. I argue that this set of assumptions is problematic because it results in ideological consequences that are both sexist and heterosexist.