Giant ultrafast Kerr effect in type-II superconductors

We study the ultrafast Kerr effect and high-harmonic generation in type-II superconductors by formulating a new model for a time-varying electromagnetic pulse normally incident on a thin-film superconductor. It is found that type-II superconductors exhibit exceptionally large $\chi^{(3)}$ due to the progressive destruction of Cooper pairs, and display high-harmonic generation at low incident intensities, and the highest nonlinear susceptibility of all known materials in the THz regime. Our theory opens up new avenues for accessible analytical and numerical studies of the ultrafast dynamics of superconductors

Adaptive Optical Devices in Vision Science

In this thesis we investigate the use of adaptive optical devices in three different areas of vision science. These areas are defocus perception, retinal imaging and severe vision loss. Birefringent material has been utilised to produce optical components that can control the angle of refraction of incident light. Using a ferroelectric liquid crystal (FLC) the orientation of linear polarised light can be controlled. This provides us with the ability to switch between the two refractive indices of birefringent materials at very high speeds. A focus switchable lens (FSL) has been made from barium borate (BBO), and a ferroelectric liquid crystal to switch between equal and opposite defocus levels to determine the optimum focus correction by making use of the human eye's sensitivity to flicker. Flicker simulation result indicate that there is a high dependence of flicker sensitivity to the flicker frequency. High spatial frequencies also increased the ability to perceive small defocus shifts. Promising results have been obtained showing a person is able to find a point of equal defocus using flicker more accurately than they would be able to find perfect focus. The same focus switching lens system has the ability to produce fast focus switching cameras. Its potential has been analysed for the use in retinal cameras to ease the process of obtaining good quality images of the optic nerve and providing such cameras with the ability to switch focus within the depth of the optic nerve head at high speeds. Simulation results showed that two FSLs positioned within the zoom system of the imaging arm are able to create focal point shifts of very small amounts. Finally, collaborative research has been conducted in the use of a birefringent prism in conjunction with an FLC to create image jitter that can enhance visual performance in people with severe visual impairment. Image jitter created on-screen and via an optical system was tested. Patients were able to increase their reading speed and improve their ability to discriminate between happy and sad faces

Cotton movement and fluctuation

[8 unnumbered pages], 156 pages : illustrations ; 22 c

A Comparative Anatomical Study of Mandibular Structure in Bees

Volume: 51Start Page: 463End Page: 48

On the auditory identifiability of Asian American identity in speech: The role of listener background, sociolinguistic awareness, and language ideologies

The current study examined the auditory identifiability of Asian American ethnoracial identity, including the role of listener characteristics and ideologies. Results of an identification experiment showed that the overall accuracy of ethnoracial identification on (East and Southeast) Asian talkers was low, but not the lowest among talker groups and not significantly different from accuracy on Black talkers. There were also significant effects of listeners' ethnoracial identity, gender, and linguistic chauvinism (i.e., disfavoring linguistic diversity in the US). In particular, being Asian or a woman was associated with a higher likelihood of accuracy, whereas greater linguistic chauvinism was, to an extent, associated with a lower likelihood of accuracy. Results of a discrimination experiment additionally showed an effect of listeners' awareness of ethnoracially-based language variation: having this awareness was associated with a higher likelihood of accuracy on discrimination trials with one or more Asian talkers. Taken together, these findings converge with previous results showing an effect of the listener's background on ethnoracial perception and further implicate the listener's sociolinguistic awareness and ideologies

Convergent adaptations: bitter manioc cultivation systems in fertile anthropogenic dark earths and floodplain soils in central Amazonia

Shifting cultivation in the humid tropics is incredibly diverse, yet research tends to focus on one type: long-fallow shifting cultivation. While it is a typical adaptation to the highly-weathered nutrient-poor soils of the Amazonian terra firme, fertile environments in the region offer opportunities for agricultural intensification. We hypothesized that Amazonian people have developed divergent bitter manioc cultivation systems as adaptations to the properties of different soils. We compared bitter manioc cultivation in two nutrient-rich and two nutrient-poor soils, along the middle Madeira River in Central Amazonia. We interviewed 249 farmers in 6 localities, sampled their manioc fields, and carried out genetic analysis of bitter manioc landraces. While cultivation in the two richer soils at different localities was characterized by fast-maturing, low-starch manioc landraces, with shorter cropping periods and shorter fallows, the predominant manioc landraces in these soils were generally not genetically similar. Rather, predominant landraces in each of these two fertile soils have emerged from separate selective trajectories which produced landraces that converged for fast-maturing low-starch traits adapted to intensified swidden systems in fertile soils. This contrasts with the more extensive cultivation systems found in the two poorer soils at different localities, characterized by the prevalence of slow-maturing high-starch landraces, longer cropping periods and longer fallows, typical of previous studies. Farmers plant different assemblages of bitter manioc landraces in different soils and the most popular landraces were shown to exhibit significantly different yields when planted in different soils. Farmers have selected different sets of landraces with different perceived agronomic characteristics, along with different fallow lengths, as adaptations to the specific properties of each agroecological micro-environment. These findings open up new avenues for research and debate concerning the origins, evolution, history and contemporary cultivation of bitter manioc in Amazonia and beyond

Reporting methodological search filter performance comparisons : a literature review

© 2014 The authors. Health Information and Libraries Journal © 2014 Health Libraries Journal.Peer reviewedPostprin