Response of Saddled Prominent (Lepidoptera: Notodontidae) Pupae to Desiccation, Cold Treatment, and Post-Cold Treatment Incubation Temperature

Saddled prominent, Heterocampa guttivitta, pupae were placed at 1.5oC for 50 to 200 days, then incubated at one of four post-cold temperatures ranging from 10° to 26.7°C. Adults emerged from pupae exposed to all cold treatment periods. A few adults also emerged from pupae that were not exposed to cold. The time required for adult emergence following cold treatment declined with longer periods of cold treatment and higher post-cold incubation temperature. The interaction between these two main effects was also significant. Adult morphogenesis begins immediately after pupation, and continues until interrupted by cold temperature. When pupae were subjected to desiccating conditions prior to cold treatment, weight loss due to desiccation was accompanied by increased mortality. Desiccation occurred faster at IS.6° than at 18.0°C. Our results identify a physical factor which might contribute to pupal overwintering mortality: prolonged excessive drought conditions between time of pupation and the onset of cold

Vision and Reading Difficulties Part 5: Clinical protocol and the role of the eye-care practitioner

This series of articles has described various aspects of visual characteristics of reading difficulties and the background behind techniques such as the use of coloured filters in helping to reduce the difficulties that are experienced. The present article, which is the last in series, aims to describe a clinical protocol that can be used by the busy eye care practitioner for the investigation and management of such patients. It also describes the testing techniques that can be used for the various assessments. Warning: DO NOT LOOK AT FIGURE 7 IF YOU HAVE MIGRAINE OR EPILEPSY

Vision and Reading Difficulties Part 4: Coloured filters - how do they work?

This article is the fourth in a series of five about vision and reading difficulties. The first article provided a general overview and the second covered conventional optometric correlates of reading difficulties (e.g. binocular vision problems). The present article continues on from the third article by describing the use of coloured filters in treating a condition now known as visual stress. Visual stress is often associated with reading difficulties, but also a variety of other neurological conditions. This article concentrates on the possible mechanisms for the benefit from coloured filters, beginning with obvious peripheral factors. The terminology for this condition has changed over the years (e.g. Scotopic Sensitivity Syndrome, and Meares-Irlen Syndrome) and the issue of terminology is discussed at the end of this article. Warning: DO NOT LOOK AT FIGURE 6 ON PAGE 33 IF YOU HAVE A MIGRAINE OR EPILEPSY

Vision and Reading Difficulties Part 1: Specific learning difficulties and vision

This article is the first in a series of five about vision and reading difficulties, and provides an introduction and an overview of learning disabilities and specific learning difficulties. It outlines the role of the optometrist in helping people with such problems; it describes the symptoms that optometrists should look for and it provides an introduction of the evidence-based approach. The second article in this series will cover the optometric and orthoptic correlates of reading difficulties. Articles three and four will describe the use of coloured filters, including background, techniques, evidence, and mechanism. The final article will draw together the themes in the series of articles and discuss the clinical protocol and the role of the eye care practitioner in managing visual factors associated with reading difficulties

Vision and Reading Difficulties Part 3: Coloured filters - do they work?

This is the third article in a series of five on Vision and Reading Difficulties. The first article provided a general overview of learning disabilities and specific learning difficulties (SpLD). It outlined the role of the optometrist in helping people with SpLD. The second article covered conventional optometric correlates of reading difficulties (e.g. binocular vision problems) This article and the next will describe the use of coloured filters to treat a condition now know as "visual stress", which is often associated with reading difficulties; the symptoms of visual stress were described in Part 1. The terminology for this condition has changed over the years (e.g. Scotopic Sensitivity syndrome, Meares-Irlen syndrome). Terminology is discussed more in Part 4

Vision and Reading Difficulties Part 2: Optometric correlates of reading difficulties

In this second article of the series on vision and reading difficulties, the optometric factors (for example refractive error and orthoptic function) that may be associated with reading problems are discussed in detail. The first article of this series introduced the correlates of, and interventions for, reading difficulties that have been supported by evidence-based research. This present article describes the optometric correlates more specifically, providing details of the aspects of visual function that ought to be considered for further investigation

Excess Electron Localization Sites in Neutral Water Clusters

We present approximate pseudopotential quantum mechanical calculations of the excess electron states of equilibrated neutral water clusters sampled by classical molecular dynamics simulations. The internal energy of the clusters are representative of those present at temperatures of 200 K and 300 K. Correlated electronic structure calculations are used to validate the pseudopotential for this purpose. We find that the neutral clusters support localized, bound excess electron ground states in about 50 % of the configurations for the smallest cluster size studied (n=20), and in almost all configurations for larger clusters (n>66). The state is always exterior to the molecular frame, forming typically a diffuse surface state. Both cluster size and temperature dependence of energetic and structural properties of the clusters and the electron distribution are explored. We show that the stabilization of the electron is strongly correlated with the pre-existing instantaneous dipole moment of the neutral clusters, and its ground state energy is reflected in the electronic radius. The findings are consistent with electron attachment via an initial surface state. The hypothetical spectral dynamics following such attachment is also discussed

Pattern-Related Visual Stress, Chromaticity, and Accommodation

PURPOSE. To investigate the impact of colored overlays on the accommodative response of individuals, with and without pattern- related visual stress (PRVS), a condition in which individuals manifest symptoms of perceptual distortion and discomfort when viewing a 3-cyc/deg square-wave grating. METHODS. Under double-masked conditions, 11 individuals who reported PRVS selected an overlay with a color individually chosen to reduce perceptual distortion of text and maximize comfort (PRVS group). Two groups of control subjects individually matched for age, sex, and refractive error were recruited. Control group 1 similarly chose an overlay to maximize comfort. Control group 2 used the same overlays as the paired PRVS participant. The overlay improved reading speed by 10% (P < 0.001), but only in the PRVS group. A remote eccentric photorefractor was used to record accommodative lag while participants viewed a cross on a background. The background was uniform or contained a grating and was either gray or had a chromaticity identical with that of the chosen overlay. There were therefore four backgrounds in all. RESULTS. Overall, the accommodative lag was 0.44 D greater in the participants with PRVS. When the background had the chosen chromaticity, the accommodative lag was reduced by an average of 0.16 D (P = 0.03) in the PRVS group, but not in the symptom-free groups: in control group 2 the colored background slightly increased the accommodative lag. CONCLUSIONS. Accommodative lag was greater in individuals susceptible to pattern-related visual stress and was reduced by a colored background. © Association for Research in Vision and Ophthalmology