1,879 research outputs found
Sampling Technique for Larvae of the Alfalfa Snout Beetle, \u3ci\u3eOtiorhynchus Ligustici\u3c/i\u3e (Coleoptera: Curculionidae)
This paper presents a sampling procedure for estimating larval populations of the alfalfa snout beetle, Otiorhynchus ligustici. The method is based on counts of the larvae taken in 16 x 16 cm quadrats of soil during early fall when the grubs are in their final two instars and feeding just below the crowns of the plant. Analysis of sampling variability showed that 200 quadrats per field are necessary to obtain adequate precision for intensive population studies but that 50 quadrats are sufficient for survey work. The pattern of counts was overdispersed but conformed to the negative binomial distribution
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'You've got dry macular degeneration, end of story': a qualitative study into the experience of living with non-neovascular age-related macular degeneration.
BACKGROUND/OBJECTIVES: To investigate the impact of non-neovascular (dry) age-related macular degeneration (AMD) on the person with respect to diagnosis, vision loss and coping strategies.
SUBJECTS/METHODS: Volunteers with dry AMD with a range of disease severity were given an eye examination and asked to describe aspects of their experience with dry AMD in a semi-structured interview. Interviews were audio-recorded, transcribed, and subjected to Framework analysis. Overarching themes were pre-defined, whilst subthemes were derived from the data. RESULTS: Twenty-seven participants (81% female), with early (nβ=β3), intermediate (nβ=β16) and advanced dry AMD (GA; nβ=β8) were interviewed. Median (interquartile range) age (years), logMAR binocular visual acuity and Pelli-Robson contrast sensitivity were 76 (71, 80), 0.2 (0.18, 0.40) and 1.65 (1.35, 1.93), respectively. Overarching themes (and subthemes) were: diagnosis (relationship with healthcare professional, psychological impact of diagnosis, and knowledge of AMD, both pre- and post-diagnosis), impact of visual loss (functional and psychological) and coping strategies (help from others and personal strategies). Many participants reported feelings of distress at the time of diagnosis and, particularly noteworthy, several reported a constant fear of their condition worsening.
CONCLUSIONS: Dry AMD, for which there is currently no treatment, can have a significant impact on individuals, even in its early stages, before significant functional vision loss is manifest, as well as in its intermediate and advanced stages. Results from this study offer important insight into the experience of living with dry AMD not previously explored. Moreover, the results have the potential to serve as an educational resource for eyecare professionals
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An Evaluation of a Battery of Functional and Structural Tests as Predictors of Likely Risk of Progression of Age-Related Macular Degeneration.
Purpose: To evaluate the ability of visual function and structural tests to identify the likely risk of progression from early/intermediate to advanced AMD, using the Age-Related Eye Disease Study (AREDS) simplified scale as a surrogate for risk of progression. The secondary aim was to determine the relationship between disease severity grade and the observed functional and structural deficits. Methods: A total of 100 participants whose AMD status varied from early to advanced were recruited. Visual function was assessed using cone dark adaptation, 14 Hz flicker and chromatic threshold tests and retinal structure was assessed by measuring drusen volume and macular thickness. The predictive value of the tests was estimated using ordinal regression analysis. Group comparisons were assessed using analysis of covariance. Results: Change in cone dark adaptation (cone Ο) and yellow-blue (YB) chromatic sensitivity were independent predictors for AMD progression risk (cone Ο, pseudo R2 = 0.35, P < 0.001; YB chromatic threshold, pseudo R2 = 0.16, P < 0.001). The only structural predictor was foveal thickness (R2 = 0.05, P = 0.047). Chromatic sensitivity and cone dark adaptation were also the best functional tests at distinguishing between severity groups. Drusen characteristics clearly differentiated between participants with early and advanced disease, but were not able to differentiate between those with early AMD and controls. Mean differences in retinal thickness existed between severity groups at the foveal (P = 0.040) and inner (P = 0.001) subfields. Conclusions: This study indicates that cone Ο, YB chromatic threshold and foveal thickness are independent predictors of likely risk of AMD progression
Germination responses of a dry sclerophyll forest soil-stored seedbank to fire related cues
Fire is an integral component of many ecosystems worldwide. Many plant species require fire-related cues, primarily heat and smoke, to trigger germination. Despite the importance of this process, the responses of many Australian species to these cues are unknown. Without this knowledge fire management strategies may be developed that are inappropriate for individual species and vegetation communities. In this study we examined the responses of a dry sclerophyll forest seed bank to heat and smoke germination cues. Analysis was possible for 48 taxa within the soil seedbank with 34 of these showing a response to one or both of the germination cues. 10 species responded to the heat treatment, 11 species responded to the smoke treatment and 13 species responded to both the heat and smoke treatments. Germination cues acted independently for all species considered. Results in this study were consistent with published reports for most species, although some differences were seen at the species and genus level. The study highlights the importance of fire-related cues in enhancing germination of a large proportion of the species occurring in dry sclerophyll forests
Breastfeeding in Saudi Arabia: A review
Background: Breastfeeding is viewed as the optimal method of infant feeding that provides many benefits to both the infant and the mother. The monitoring and reporting of breastfeeding indicators are essential for any country to plan and implement effective promotion programs for sustainable breastfeeding. The aim of this review is to examine the available studies and data on breastfeeding in Saudi Arabia, and determine the potential factors that affect breastfeeding practices and duration in this country. Methods: The databases of Web of Knowledge, Science Direct and PubMed were searched using the relevant key words. Only studies that reported breastfeeding practices, rates and indicators in Saudi Arabia were included. Standard WHO definitions for breastfeeding categories were used in this review.Results: Seventeen cross-sectional studies were identified and reviewed and five stated they used standard definitions. The self-administered questionnaire as a measurement tool was the predominant method of data collection. Infants' ages range from less than six months up to five years. Initiation rates were high (mostly above 90%), but a few studies reported low rates of timely initiation (within the first hour). The exclusive breastfeeding rate could not be accurately determined as rates range from 0.8% to 43.9% among studies due to the lack of clear definitions and the nature of study design. The partial (mixed) feeding method was common and the category of 'any breastfeeding' has generally high rates. The mean duration of breastfeeding has showed a progressive decline over time from 13.4 months in 1987 to 8.5 months in 2010. Factors associated with a high prevalence of breastfeeding and longer duration include increased maternal age, low educational levels, rural residence, low income, multiparity and avoiding contraceptives. The most common reason for breastfeeding cessation was insufficient breast milk. Other reasons include sickness, new pregnancy and breastfeeding problems. Conclusions: Breastfeeding indicators in Saudi Arabia could not be monitored or compared relying on the available data because no longitudinal studies have been conducted in this country. A cohort study design would be the most appropriate procedure to rigorously assess and report valid results on breastfeeding practices and patterns in the Saudi society
Can Changes in Eye Movement Scanning Alter the Age-Related Deficit in Recognition Memory?
Older adults typically exhibit poorer face recognition compared to younger adults. These recognition differences may be due to underlying age-related changes in eye movement scanning. We examined whether older adultsβ recognition could be improved by yoking their eye movements to those of younger adults. Participants studied younger and older faces, under free viewing conditions (bases), through a gaze-contingent moving window (own), or a moving window which replayed the eye movements of a base participant (yoked). During the recognition test, participants freely viewed the faces with no viewing restrictions. Own-age recognition biases were observed for older adults in all viewing conditions, suggesting that this effect occurs independently of scanning. Participants in the bases condition had the highest recognition accuracy, and participants in the yoked condition were more accurate than participants in the own condition. Among yoked participants, recognition did not depend on age of the base participant. These results suggest that successful encoding for all participants requires the bottom-up contribution of peripheral information, regardless of the locus of control of the viewer. Although altering the pattern of eye movements did not increase recognition, the amount of sampling of the face during encoding predicted subsequent recognition accuracy for all participants. Increased sampling may confer some advantages for subsequent recognition, particularly for people who have declining memory abilities
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Nutritional and smoking advice recalled by patients attending a UK age-related macular degeneration clinic
Background: Age-related macular degeneration (AMD) is responsible for half of registered visual impairment in the UK. The Royal College of Ophthalmologists recommends providing guidance to people with AMD regarding smoking, diet, and nutritional supplements. The aim of this study was to investigate lifestyle advice recalled by patients with neovascular AMD (nAMD). Methods: The study took place at a UK hospital outpatients' clinic. Eligible patients with unilateral nAMD were presented with a survey about lifestyle advice provision. Results: Of 248 respondents, only 39.9% remembered receiving advice regarding diet at the hospital. Only 24.2% of respondents recalled receiving advice regarding nutritional supplements, and only 19.8% of respondents started taking daily supplements as a result of their AMD. The most prevalent reason for not taking supplements amongst those advised to do so was lack of understanding of how it would help their eyes. Nearly 13% of the sample reported currently smoking, 53.1% of which reported that they were advised to stop smoking when diagnosed with AMD. Conclusion: The findings suggest that it would be beneficial to review the provision of lifestyle advice to patients attending AMD outpatients' clinics, and to consider whether advice is being provided in an optimal format for later recall
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Functional Imaging of the Outer Retinal Complex using High Fidelity Imaging Retinal Densitometry
We describe a new technique, high fidelity Imaging Retinal Densitometry (IRD), which probes the functional integrity of the outer retinal complex. We demonstrate the ability of the technique to map visual pigment optical density and synthesis rates in eyes with and without macular disease. A multispectral retinal imaging device obtained precise measurements of retinal reflectance over space and time. Data obtained from healthy controls and 5 patients with intermediate AMD, before and after photopigment bleaching, were used to quantify visual pigment metrics. Heat maps were plotted to summarise the topography of rod and cone pigment kinetics and descriptive statistics conducted to highlight differences between those with and without AMD. Rod and cone visual pigment synthesis rates in those with AMD (vβ=β0.043βSD 0.019βmin-1 and vβ=β0.119βSD 0.046βmin-1, respectively) were approximately half those observed in healthy controls (vβ=β0.079βSD 0.024βmin-1 for rods and vβ=β0.206βSD 0.069βmin-1 for cones). By mapping visual pigment kinetics across the central retina, high fidelity IRD provides a unique insight into outer retinal complex function. This new technique will improve the phenotypic characterisation, diagnosis and treatment monitoring of various ocular pathologies, including AMD
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The effect of non-neovascular age-related macular degeneration on face recognition performance
PURPOSE: There is a well-established research base surrounding face recognition in patients with age-related macular degeneration (AMD). However, much of this existing research does not differentiate between results obtained for 'wet' AMD and 'dry' AMD. Here, we test the hypothesis that face recognition performance is worse in patients with dry AMD compared with visually healthy peers. METHODS: Patients (>60Β years of age, logMAR binocular visual acuity 0.7 or better) with dry AMD of varying severity and visually healthy age-related peers (controls) completed a modified version of the Cambridge Face Memory Test (CFMT). Percentage of correctly identified faces was used as an outcome measure for performance for each participant. A 90% normative reference limit was generated from the distribution of CFMT scores recorded in the visually healthy controls. Scores for AMD participants were then specifically compared to this limit, and comparisons between average scores in the AMD severity groups were investigated. RESULTS: Thirty patients (median [interquartile range] age of 76 [70, 79] years) and 34 controls (median age of 70 [64, 75] years) were examined. Four, seventeen and nine patients were classified as having early, intermediate and late AMD (geographic atrophy) respectively. Five (17%) patients recorded a face recognition performance worse than the 90% limit (Fisher's exact test, pΒ =β0.46) set by controls; four of these had geographic atrophy. Patients with geographic atrophy identified fewer faces on average (Β±SD) (61%βΒ±β22%) than those with early and intermediate AMD (75βΒ±β11%) and controls (74%βΒ±β11%). CONCLUSIONS: People with dry AMD may not suffer from problems with face recognition until the disease is in its later stages; those with late AMD (geographic atrophy) are likely to have difficulty recognising faces. The results from this study should influence the management and expectations of patients with dry AMD in both community practice and hospital clinics
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