The use of cues to convergence and accommodation in naive, uninstructed participants

A remote haploscopic video refractor was used to assess vergence and accommodation responses in a group of 32 emmetropic, orthophoric, symptom free, young adults naïve to vision experiments in a minimally instructed setting. Picture targets were presented at four positions between 2 m and 33 cm. Blur, disparity and looming cues were presented in combination or separately to asses their contributions to the total near response in a within-subjects design. Response gain for both vergence and accommodation reduced markedly whenever disparity was excluded, with much smaller effects when blur and proximity were excluded. Despite the clinical homogeneity of the participant group there were also some individual differences

Unemployment insurance savings accounts in Latin America : overview and assessment

The unemployment protection systems that exist in most Latin American economies are generally considered inadequate in terms of providing insurance to workers and are prone to generate stratified labor markets. Recently, research effort and policy interest has turned to Unemployment Insurance Savings Accounts (UISAs) as an alternative to traditional systems of unemployment insurance. UISAs are schemes of individual mandatory savings that smooth income over an individual's life cycle time rather than pooling unemployment risk over the total working population at a point in time. Although this form of unemployment insurance diminishes the moral hazard problems associated with traditional insurance methods, it presents problems of its own. First, it is questionable that these systems provide adequate protectionagainst unemployment risk. Additionally, their effects on the promotion of informal labor markets and their administrative costs are yet to be determined. Finally, the effectiveness as a form of unemployment insurance depends critically upon the performance and credibility of the financial institutions managing the funds. This paper examines the experience of Latin American countries that use UISAs, with the hope of highlighting the problems of the system and identifying areas for future theoretical and empirical work. In conclusion, the overall effect of UISAs depends on a vast array of specific country characteristics and program parameters. The way the system is implemented, existing labor regulation, the extent of the informal economy and the scope for collusive behavior greatly influence the success of these programs. This calls for a more extensive research effort in the area.Labor Markets,,Labor Policies,Access to Finance,Banks&Banking Reform

Independent and reciprocal accommodation in anisometropic amblyopia

Accommodation is considered to be a symmetrical response and to be driven by the least ametropic and nonamblyopic eye in anisometropia. We report the case of a 4-year-old child with anisometropic amblyopia who accommodates asymmetrically, reliably demonstrating normal accommodation in the nonamblyopic eye and antiaccommodation of the amblyopic eye to near targets. The abnormal accommodation of the amblyopic eye remained largely unchanged during 7 subsequent testing sessions undertaken over the course of therapy. We suggest that a congenital dysinnervation syndrome may result in relaxation of accommodation in relation to near cues and might be a hitherto unconsidered additional etiological factor in anisometropic amblyopia

Wages, Skills, and Technology in the United States and Canada

Wages for more- and less-educated workers have followed strikingly different paths in the U.S. and Canada. During the 1980's and 1990's, the ratio of earnings of university graduates to high school graduates increased sharply in the U.S. but fell slightly in Canada. Katz and Murphy (1992) found that for the U.S. a simple supply-demand model fit the pattern of variation in the premium over time. We find that the same model and parameter estimates explain the variation between the U.S. and Canada. In both instances, the relative demand for more-educated labor shifts out at the same, consistent rate. Both over time and between countries, the variation in rate of growth of relative wages can be explained by variation in the relative supply of more-educated workers. Many economists suspect that technological change is causing the steady increases in the relative demand for more-educated labor. If so, these data provide independent evidence on the spatial and temporal variation in the pattern of technological change. Whatever is causing this increased demand for skill, the evidence from Canada suggest that increases in educational attainment and skills can reduce the rate at which relative wages diverge.

Emulating Evolutionary Principles For Agriculture: Designing a Biomimetic Vertical Garden by Mimicking Tracheophyte Evolution

Biodiversity, particularly in the world’s equatorial regions, is under threat from human industry. Among the most daunting problems facing these biomes is that of the food industry’s continual expansion into what was once rainforest. Expansive monoculture (large cultivated swaths of a single crop species) are the primary threat to tropical biodiversity. This method of agriculture is harmful because it requires the clearing of land that once supported thousands of species in order to replace it with rows of a single crop. If more plants could be grown in a smaller horizontal square footage, farms need not rely so heavily on the clearing of undisturbed land. The objective of this project is to create a novel vertical housing unit for a model crop species, garden strawberries (Fragaria x ananassa), utilizing biomimetic principles in order to maximize plant growth while minimizing horizontal expansion. The creation of the vertical garden design involved analysis into recent applications of biomimicry in agriculture, particularly those employed in highly developed urban areas. After reviewing sources related to biomimesis and vertical garden projects, a 3D model was constructed utilizing CAD software. Design elements from Grant Associates’ biomimetic Supertrees were modified to incorporate hanging planters for stolon-producing strawberries. An aluminum chassis based on the 3D model was welded together, and finally, bare-root strawberries were placed within the tower

An analysis of personal problems reported by 163 Canadian nursing students

Thesis (M.S.)--Boston University, 1951. This item was digitized by the Internet Archive

The development of direct payments in the UK: implications for social justice

Direct payments have been heralded by the disability movement as an important means to achieving independent living and hence greater social justice for disabled people through enhanced recognition as well as financial redistribution. Drawing on data from the ESRC funded project Disabled People and Direct Payments: A UK Comparative Perspective, this paper presents an analysis of policy and official statistics on use of direct payments across the UK. It is argued that the potential of direct payments has only partly been realised as a result of very low and uneven uptake within and between different parts of the UK. This is accounted for in part by resistance from some Labour-controlled local authorities, which regard direct payments as a threat to public sector jobs. In addition, access to direct payments has been uneven across impairment groups. However, from a very low base there has been a rapid expansion in the use of direct payments over the past three years. The extent to which direct payments are able to facilitate the ultimate goal of independent living for disabled people requires careful monitoring

Biological motion cues aid identification of self-motion from optic flow but not heading detection

© 2017 The Authors. When we move through the world, a pattern of expanding optic flow is generated on the retina. In completely rigid environments, this pattern signals one's direction of heading and is an important source of information for navigation. When we walk towards an oncoming person, the optic environment is not rigid, as the motion vectors generated by the other person represent a composite of that person's movement, his or her limb motion, and the observer's self-motion. Though this biological motion obfuscates the optic flow pattern, it also provides cues about the movement of other actors in the environment. It may be the case that the visual system takes advantage of these cues to simplify the decomposition of optic flow in the presence of other moving people. The current study sought to probe this possibility. In four experiments self-motion was simulated through an environment that was empty except for a single, walking point-light biological motion stimulus. We found that by using biological motion cues, observers were able to identify the presence of selfmotion despite the lack of stable scene information. However, when estimating heading based on these stimuli, the pattern of observer heading estimates could be approximately reproduced by computing the vector sum of the walker's translation and the stimulated selfmotion. This suggests that though biological motion can be used to disentangle self-motion in ambiguous situations, optic flow analysis does not use this information to derive heading estimates

Receding and disparity cues aid relaxation of accommodation

Purpose. Accommodation can mask hyperopia and reduce the accuracy of non-cycloplegic refraction. It is, therefore, important to minimize accommodation to obtain a measure of hyperopia as accurate as possible. To characterize the parameters required to measure the maximally hyperopic error using photorefraction, we used different target types and distances to determine which target was most likely to maximally relax accommodation and thus more accurately detect hyperopia in an individual. Methods. A PlusoptiX SO4 infra-red photorefractor was mounted in a remote haploscope which presented the targets. All participants were tested with targets at four fixation distances between 0.3 and 2 m containing all combinations of blur, disparity, and proximity/looming cues. Thirty-eight infants (6 to 44 weeks) were studied longitudinally, and 104 children [4 to 15 years (mean 6.4)] and 85 adults, with a range of refractive errors and binocular vision status, were tested once. Cycloplegic refraction data were available for a sub-set of 59 participants spread across the age range. Results. The maximally hyperopic refraction (MHR) found at any time in the session was most frequently found when fixating the most distant targets and those containing disparity and dynamic proximity/looming cues. Presence or absence of blur was less significant, and targets in which only single cues to depth were present were also less likely to produce MHR. MHR correlated closely with cycloplegic refraction (r = 0.93, mean difference 0.07 D, p = n.s., 95% confidence interval +/-<0.25 D) after correction by a calibration factor. Conclusions. Maximum relaxation of accommodation occurred for binocular targets receding into the distance. Proximal and disparity cues aid relaxation of accommodation to a greater extent than blur, and thus non-cycloplegic refraction targets should incorporate these cues. This is especially important in screening contexts with a brief opportunity to test for significant hyperopia. MHR in our laboratory was found to be a reliable estimation of cycloplegic refraction. (Optom Vis Sci 2009;86:1276-1286