Sensory imagery in individuals who are blind and sighted: examining unimodal and multimodal forms

Introduction: Previous research has suggested that visual images are more easily generated, more vivid and more memorable than other sensory modalities. This research examined whether or not imagery is experienced in similar ways by people with and without sight. Specifically, the imabeability of visual, auditory and tactile cue words was compared. The degree to which images were multimodal or unimodal was also examined. Method: Twelve participants totally blind from early infancy and 12 sighted participants generated images in response to 53 sensory and non sensory words, rating imageability and the sensory modality, and describing images. From these 53 items, 4 subgroups of words, which stimulated images that were predominantly visual, tactile, auditory and low-imagery, respectively, were created. Results: T-tests comparing imageability ratings from blind and sighted participants found no differences for auditory and tactile words (both p>.1). Nevertheless, whilst participants without sight found auditory and tactile images equally imageable, sighted participants found images in response to tactile cue words harder to generate than visual cue words (mean difference: -0.51, p=.025). Participants with sight were also more likely to develop multisensory images than were participants without sight (both U≥15.0, N1=12, N2=12, p≤.008). Discussion: For both the blind and sighted, auditory and tactile images were rich and varied and similar language was used. Sighted participants were more likely to generate multimodal images. This was particularly the case for tactile words. Nevertheless, cue words that resulted in multisensory images were not necessarily rated as more imageable. The discussion considers whether or not multimodal imagery represent a method of compensating for impoverished unimodal imagery. Implications for Practitioners: Imagery is important not only as a mnemonic in memory rehabilitation, but also everyday uses for things such as autobiographical memory. This research emphasises both the importance of not only auditory and tactile sensory imagery, but also spatial imagery for people without sight.

An efficient method for optimal location and sizing of fixed and switched shunt capacitors in large distribution systems

This paper proposes a computationally efficient methodology for the optimal location and sizing of static and switched shunt capacitors in large distribution systems. The problem is formulated as the maximization of the savings produced by the reduction in energy losses and the avoided costs due to investment deferral in the expansion of the network. The proposed method selects the nodes to be compensated, as well as the optimal capacitor ratings and their operational characteristics, i.e. fixed or switched. After an appropriate linearization, the optimization problem was formulated as a large-scale mixed-integer linear problem, suitable for being solved by means of a widespread commercial package. Results of the proposed optimizing method are compared with another recent methodology reported in the literature using two test cases: a 15-bus and a 33-bus distribution network. For the both cases tested, the proposed methodology delivers better solutions indicated by higher loss savings, which are achieved with lower amounts of capacitive compensation. The proposed method has also been applied for compensating to an actual large distribution network served by AES-Venezuela in the metropolitan area of Caracas. A convergence time of about 4 seconds after 22298 iterations demonstrates the ability of the proposed methodology for efficiently handling large-scale compensation problems.

Tipologia, instalação, funcionamento e manutenção dos diversos tipos de aparelhos de apoio em obras de arte

Trabalho Final para a obtenção do grau de Mestre em Engenharia Civil

Inefficient commuting in a city with spillovers

A Masters Thesis, presented as part of the requirements for the award of a Research Masters Degree in Economics from NOVA – School of Business and Economics

Is low worker mobility evidence for monopsony power?

Major in Competition and Regulation

On the labor share the long-run equilibrium and its adjustment process

This research computes an Equilibrium Labor Share using a VECM for a panel of 19 countries, analyzes what determines the speed at which the labor share adjusts towards that equilibrium and decomposes this adjustment in terms of real wages and employment. Results suggest that the speed at which a country adjusts decreases with employment protection legislation and labor taxes. Most countries’ labor shares adjustment is made through real wages changes instead of changing employment, suggesting that wage moderation policies may play an important role on the adjustment process without harming employment. Keywords: Equilibrium

On the labor share the long-run equilibrium and its adjustment process

This research computes an Equilibrium Labor Share using a VECM for a panel of 19 countries, analyzes what determines the speed at which the labor share adjusts towards that equilibrium and decomposes this adjustment in terms of real wages and employment. Results suggest that the speed at which a country adjusts decreases with employment protection legislation and labor taxes. Most countries’ labor shares adjustment is made through real wages changes instead of changing employment, suggesting that wage moderation policies may play an important role on the adjustment process without harming employment.

Assessing the role of social networks on migrant labor market outcomes: Evidence from a representative immigrant survey

What role do social networks play in determining migrant labor market outcomes? We examine this question using data from a random sample of 1500 immigrants living in Ireland. We propose a theoretical model formally predicting that immigrants with more contacts have additional access to job offers, and are therefore better able to become employed and choose higher paid jobs. Our empirical analysis confirms these findings, while focusing more generally on the relationship between migrants’ social networks and a variety of labor market outcomes (namely wages, employment, occupational choice and job security), contrary to the literature. We find evidence that having one more contact in the network is associated with an increase of 11pp in the probability of being employed and with an increase of about 100 euros in the average salary. However, our data is not suggestive of a network size effect on occupational choice and job security. Our findings are robust to sample selection and other endogeneity concerns.

Firing and training costs and labour market segmentation

This dissertation consists of three essays on the labour market impact of firing and training costs. The modelling framework resorts to the search and matching literature. The first chapter introduces firing costs, both liner and non-linear, in a new Keynesian model, analysing business cycle effects for different wage rigidity degrees. The second chapter adds training costs in a model of a segmented labour market, accessing the interaction between these two features and the skill composition of the labour force. Finally, the third chapter analyses empirically some of the issues raised in the second chapter.

Change in individual growth rate and its link to gill-net fishing in two sympatric whitefish species

Size-selective fishing is expected to affect traits such as individual growth rate, but the relationship between the fishery-linked selection differentials and the corresponding phenotypic changes is not well understood. We analysed a 25-year monitoring survey of sympatric populations of the two Alpine whitefish Coregonus albellus and C. fatioi. We determined the fishing-induced selection differentials on growth rates, the actual change of growth rates over time, and potential indicators of reproductive strategies that may change over time. We found marked declines in adult growth rate and significant selection differentials that may partly explain the observed declines. However, when comparing the two sympatric species, the selection differentials on adult growth were stronger in C. albellus while the decline in adult growth rate seemed more pronounced in C. fatioi. Moreover, the selection differential on juvenile growth was significant in C. albellus but not in C. fatioi, while a significant reduction in juvenile growth over the last 25 years was only found in C. fatioi. Our results suggest that size-selective fishing affects the genetics for individual growth in these whitefish, and that the link between selection differentials and phenotypic changes is influenced by species-specific factors.

Snapshot gradient-recalled echo-planar images of rat brains at long echo time at 9.4 T.

With improved B 0 homogeneity along with satisfactory gradient performance at high magnetic fields, snapshot gradient-recalled echo-planar imaging (GRE-EPI) would perform at long echo times (TEs) on the order of T2*, which intrinsically allows obtaining strongly T2*-weighted images with embedded substantial anatomical details in ultrashort time. The aim of this study was to investigate the feasibility and quality of long TE snapshot GRE-EPI images of rat brain at 9.4 T. When compensating for B 0 inhomogeneities, especially second-order shim terms, a 200 x 200 microm2 in-plane resolution image was reproducibly obtained at long TE (>25 ms). The resulting coronal images at 30 ms had diminished geometric distortions and, thus, embedded substantial anatomical details. Concurrently with the very consistent stability, such GRE-EPI images should permit to resolve functional data not only with high specificity but also with substantial anatomical details, therefore allowing coregistration of the acquired functional data on the same image data set.

Production under glass : working conditions and class-consciousness of the Niagara greenhouse workers

This study applies a Marxist theoretical paradigm to examine the working conditions of greenhouse workers in the Niagara Region, and the range of factors that bear upon the formation of their class-consciousness. The Niagara greenhouse industry represents one of the most developed horticultural regions in Canada and plays a prominent role in the local economy. The industry generates substantial revenues and employs a significant number of people, yet the greenhouse workers are paid one of the lowest rates in the region. Being classified as agricultural workers, the greenhouse employees are exempted from many provisions of federal and provincial labour regulations. Under the current provincial statutes, agricultural workers in Ontario are denied the right to organize and bargain collectively. Except for a few technical and managerial positions, the greenhouse industry employs mostly low-skilled workers who are subjected to poor working conditions that stem from the employer's attempts to adapt to larger structural imperatives of the capitalist economy. While subjected to these poor working conditions, the greenhouse workers are also affected by objectively alienated social relations and by ruling class ideological domination and hegemony. These two sets of factors arise from the inherent conflict of interests between wage-labour and capital but also militate against the development of class-consciousness. Semi-structured interviews were conducted with 12 greenhouse workers to examine the role played by their material circumstances in the formulation of their social and political views as well as the extent to which they are aware of their class location and class interests. The hegemonic notions of 'common sense' acted as impediments to formation of classconsciousness. The greenhouse workers have virtually no opportunities to access alternative perspectives that would address the issues associated with exploitation in production and offer solutions leading to 'social justice'. Fonnidable challenges confront any organized political body seeking to improve the conditions of the working people.

Can low domain knowledge be compensated for when using the internet? /

Previous researchers have found that learners do not benefit fi-om using the Internet when domain knowledge is low. The purpose of the current study was to investigate possible methods to compensate for low domain knowledge. Specifically, the presence of notes, more time to search the Internet, and high levels of motivation to use the Internet were examined as possible compensating factors. Sixty Political Science and Kinesiology undergraduate students were randomly assigned to one of three conditions. Students searched the Internet for an hour prior to vmting an essay with notes present, searched the Internet for an hour prior to writing an essay without notes present, or did not search the Internet prior to completing an essay. Each participant completed the same two essays, one corresponding to a high knowledge domain and another corresponding to a low knowledge domain. First, the presence of notes did not significantly improve essay scores in comparison to the absence of notes. Second, learners did benefit fi-om using the Internet for 1 hour in comparison to their peers who were not exposed to the Internet, regardless of level of domain knowledge. Third, high levels of motivation did not affect essay performance. A discussion of why time may have compensated for low domain knowledge while notes and motivation did not is included. In addition, methods that may compensate for low domain knowledge when time is restricted are suggested.

From protest to powerlessness : a Marxist analysis of the Ontario NDP /

Using Marxist state theory as an analytical framework, this thesis explains the problems faced by the Ontario New Democratic Party government (1990-1995) in implementing a social democratic agenda. Not only was the government constrained in its ability to implement progressive policy, but it was also pushed to implement a Social Contract (involving legislated wage cuts to public sector employees) that alienated the party's base of support, making it more difficult for the party to organize in the future. Although this study relies predominantly on a reinterpretation of existing research on the topic, some primary research is used in the analysis, including interviews with members of the labour movement and former MPPs and analysis of the news media's treatment of the party/ government. Historical and class analytical perspectives are used to explain the evolution of the ONDP's structure and policies, as well as to assess the relative strength of the working class and its ability to support a social democratic political agenda. It was found that the ONDP' s unwillingness to develop a long term plan for social democracy, and its inability to act as a mass party or to build a strong working class movement, made it more difficult for the party to succeed when it formed the government. Moreover, the class nature of the capitalist state, along with pressure exerted by a well mobilized capitalist class, worked to limit the government' s options.

Effect of age on female choice in the field cricket, Gryllus interger

Female choice is an important element of sexual selection that may vary among females of the same species. Few researchers have investigated the causes of variation in selectivity with respect to potential mates and overall level of motivation toward a stimulus source representative of a mate. This study demonstrates that female age may be one cause of variation in female choice. Females of different ages may have different mate preferences. As females age, they have less time left to reproduce, and their residual reproductive value decreases. This should correspond to a higher reproductive effort which may be represented as increased motivation and/or decreased selectivity. The effect of age on mate choice in Gryllus integer was investigated by using a non-compensating treadmill, called the Kugel, to measure female phonotaxis. Artificially generated male calling songs of varying pulse rates were broadcast in either a singlestimulus or a three-stimulus experimental design. The pulse rates used in the calling song stimuli were 70, 64, 76, 55 and 85 pulses per second. These corresponded to the documented mean pulse rate for the species at the experimental temperature, one standard deviation below and above the mean, and 2.5 standard deviations below and above the mean, respectively. Test females were either 11-14 days or 25-28 days post-ecdysis. Trials usually were conducted two to seven hours into the scotophase. In the single-stimulus experiment, females were presented with stimuli with only one pulse rate. Older females achieved higher vector scores than younger females, indicating that older females are more motivated to mate. Both groups showed little phonotactic response towards 55 or 85 pIs, both of which lie outside the natural range of G. integer calling song at the experimental temperature. Neither group discriminated among the three pulse rates that fell within the natural range of calling song. In the three-stimulus experiment, females were presented with stimuli with one of three pulse rates, 64, 70 or 76 pIs, In alternation. Both age groups had reduced responsiveness in this experiment, perhaps due to an increase in perceived male density. Additionally, younger females responded significantly more to 64 and 70 pIs than to the higher pulse rate, indicating that they are selective with respect to mate choice. Older females did not discriminate among the three pulse rates. Therefore, it was concluded that selectivity decreases with age. A further study was conducted to determine that these effects were due to age and not due to the differing periods without a mating between the two age groups. Again, stimuli were presented in a three-stimulus experimental design. Age was held constant at 28 days and time since last mating varied from 11 to 25 days. Females varyIng in time since last mating did not differ in their responses to the calling song pulse rates. This indicated that the increased motivation and decreased selectivity exhibited In the initial experiments were due to age and not to time without a mating. Neither time of trial nor female weight had an effect upon female phonotaxis. Data are discussed in terms of mate choice, residual reproductive value, and costs of choice.