Young children's understanding of disabilities: the influence of development, context and cognition

Throughout Europe, educational support for children with disabilities has moved towards a model of inclusive education. Such policy changes mean that for all children there will be an increased likelihood of working with and encountering children with differing disabilities and difficulties. Previous research had indicated that children had poorly differentiated views of developmental differences. The present study investigated children?s representations of different disabilities. Seventy-nine 8-9 and 10-11 year old Greek children from an urban school and a rural school completed an attitudes toward school inclusion rating scale and a semi-structured interview. Responses to the attitude scale provided generally positive views of educational inclusion. However, children were less positive about activities that might directly reflect upon themselves. Children?s responses in the interviews indicated that they were developing rich representations of differences and diversities. Children had the greatest understanding of sensory and physical disabilities, followed by learning disabilities. There was limited knowledge of dyslexia and hyperactivity and no child was familiar with the term autism. Both groups of children identified a range of developmental difficulties, with older children being more aware of specific learning disabilities, their origin and impact. Results are discussed in terms of children?s developing knowledge systems and the implications for educational practices

Influence of the duration of anoxia on mortality.

<p>A, B. Male w¹¹¹⁸ flies were adapted for 2 days to a 1S1Y diet (A) or a 10S10Y diet (B), exposed to the indicated times of anoxia, reoxygenated, switched to a 10S10Y diet and survivorship curves were determined. Sample sizes are indicated in parentheses. Note that A/R stresses mainly reduce the short term mortality and have less effect on maximum longevities. C–E. Relationship between the duration of anoxia and the short term mortality for young male flies (C), young female flies (D) and 1 month old male flies (E). In panels D and E, the grey lines reproduce the curves obtained for young males (panel C). Sample sizes were 40–113. Aged males were maintained on a standard food medium for 1 month, switched either to a 1S1Y or a 10S10Y diet for two days and then A/R stressed. F. Norms of reaction of flies of different strains as indicated. Young male flies were used. Sample sizes (starved, fed) are indicated in parentheses. Differences between strains are not statistically significant.</p

Long A/R stresses induce a transient increase in mortality rates.

<p>A. Survivorship of A/R stressed flies. Male w¹¹¹⁸ flies were exposed to 2 h or 3.5 h of anoxia (∼1% O₂), reoxygenated and survivorships curves were determined. Demographic parameters were: median longevity (control, 32 days, 2 h A/R stress, 26 days, 3.5 h A/R stress, 3.5 days), maximum longevity (control, 50 days, 2 h A/R stress, 46 days, 3.5 h A/R stress, 38 days), sample sizes (control, 1021, 2 h A/R stress, 886, 3.5 h A/R stress, 862). B. Age specific mortalities were plotted against age using a log scale. The trajectory mortality of control flies (dotted black) is consistent with a Gompertz model. Three phases, labelled I, II and III, are distinguished (see text). A Cox regression analysis was performed. A 2 h A/R stress increased the relative risk of death 8.6 fold (95%CI: 6.0–12.3). A 3.5 h A/R stress increased the relative risk of death 20.1 fold (95% CI: 14.2–28.5). Sample sizes were: control, 1021, 2 h A/R stress, 886, 3.5 h A/R stress, 862. After 10 days of recovery, relative risks of death were 2.19 (95% CI: 1.85–2.60) and 1.79 (95% CI: 1.63–1.96) for 2 h A/R stressed flies and 3.5 h A/R stressed flies respectively. Sample sizes were: control, 987, 2 h A/R stress, 655, 3.5 h A/R stress, 388. After 30 days of recovery, relative risks of death were: 1.26 (95% CI: 1.11–1.44) and 1.22 (95% CI: 1.12–1.34 for 2 h A/R stressed flies and 3.5 h A/R stressed flies respectively. Sample sizes were: control, 725, 2 h A/R stress, 353, 3.5 h A/R stress, 159. C. Interpretation of the data. Two mortality components are defined. (i) An A/R stress induced mortality that reached a maximum 24 h after reoxygenation and that declines (blue) and (ii) the age associated exponential increase in mortality rate (yellow).</p

The sensitivity of mutants of the insulin signalling pathway to A/R stresses.

<p>Flies of different genotypes were adapted for 2 days to a 10S10Y diet (filled bars) or a 1S1Y diet (open bars), exposed to a 3.5 h A/R stress, reoxygenated and switched to a 10S10Y diet. Surviving flies were counted after 48 hours. Mean±sem are shown. The numbers of flies used are indicated in parentheses.</p

A severe dietary restriction protects flies against A/R injuries.

<p>A. Fed flies were anoxia sensitive. One day old flies were fed on a rich 10S10Y diet. After 2 days, flies were exposed to 3.5 hours of severe anoxia (<0.1% O₂) and reoxygenated. The survivorship curve (black) is compared to that of normoxic flies on the same diet (grey). Few flies (∼3%) recovered from the A/R stress. The largest mortality as compared to the experiments shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0005422#pone-0005422-g001" target="_blank">Figure 1</a> was due to the use of more severe anoxic conditions (0.1% O₂ versus 1% O₂). Sample sizes were 109 (controls) and 120 (A/R stressed flies). B. Dietary restricted flies were anoxia resistant. One day old flies were fed on a poor 1S1Y diet. After 2 days, flies were exposed to 3.5 hours of anoxia, reoxygenated and maintained on the same 1S1Y diet. The survivorship curve (black) is compared to that of normoxic flies maintained on a 1S1Y diet (grey). P = 0.0095 using the Log rank test. Mean longevities were 10.2±0.77 days (n = 98) and 8.43±0.50 days (n = 219) for control and A/R stressed flies respectively. C. An assay for the diet dependent tolerance to A/R stresses. Survivorship curves of three groups of flies are compared. Grey continuous curve: One day old flies were fed on a 1S1Y diet and switched after 2 days to a 10S10Y diet. Black curve. One day old flies were fed for 2 days on a 1S1Y diet, A/R stressed (3.5 h) and switched to a 10S10Y diet. The difference between the two curves documents the influence of the A/R stress on dietary restricted flies. An A/R stress mainly increased the short term mortality. The dotted grey line shows for comparison the survivorship curve of normoxic flies maintained on a 10S10Y diet. The difference with the continuous grey line documents the action of a 1S1Y to 10S10Y diet shift on longevity. The comparison shows that shifting flies from a 1S1Y diet to a 10S10Y diet rapidly restored low mortality rates. Arrows in panels A–C show maximum longevities. D. Influence of different protocols of dietary restriction on survival following an A/R stress. One day old flies were maintained on a 1S1Y diet (thin lines) or a 10S10Y diet (thick lines) for the times indicated and then exposed to a 3.5 h A/R stress. Surviving flies were scored after 48 hours. Five different experimental protocols are compared. Experiments #2 and #3 reproduced the data presented in panels A and C. Experiment #1 shows that a one day adaptation to a 1S1Y diet did not induce a maximum protection against A/R stresses. Experiment #4 shows that the protective action of a 1S1Y diet was completely lost when flies were shifted back to a 10S10Y diet for 24 hours.</p

Body composition of anoxia tolerant and sensitive flies.

<p>Male w¹¹¹⁸ flies were fed for 2 days either on a 1S1Y diet or a 10S10Y diet to produce anoxia tolerant or anoxia sensitive states. Flies were then killed (columns 2 and 3) or exposed to a 1 h anoxia (columns 4 and 5) and killed. Total levels of ATP, lactate, phosphate, glycogen, triglycerides and proteins were determined as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0005422#s4" target="_blank">Materials and Methods</a>. Means±sem and the number of independent experiments performed are indicated. AU: arbitrary units, ND: Not determined. §: p>0.05 as compared to starvation stressed flies after 1 h of anoxia. §§: p>0.05 as compared to starvation stressed flies. Other differences were statistically significant (p<0.01).</p

The sensitivity of sima⁰⁷⁶⁰⁷/⁰⁷³⁰⁷ flies to A/R stresses.

<p>A. Sima ⁰⁷⁶⁰⁷/⁰⁷³⁰⁷ flies were adapted for 2 days to 10S10Y (black) or a 1S1Y (grey) nutrient diet, exposed to a 3.5 h A/R stress, reoxygenated and switched to a 10S10Y diet. Survivorship curves were determined. Mean longevities were 17.1±1.3 days (n = 69) and 1.37±0.3 days (n = 66) for flies adapted to 10S10Y and 1S1Y diet respectively. B. Norms of reaction. Flies of different genotypes were adapted for 2 days to either a 10S10Y or a 1S1Y diet. They were exposed to a 3.5 h A/R stress, reoxygenated and surviving flies were counted after 48 hours. Sample sizes (starved, fed) are indicated in parentheses. Differences between genotypes were not statistically significant.</p

Pharmacological interventions.

<p>A. AICAR increases the tolerance of the <i>w¹¹¹⁸</i> flies to A/R stresses in a diet independent manner. Flies were maintained for 2 days on a 1S1Y or a 10S10Y diet supplemented with 100 mM AICAR, 100 mM 5(4)-Aminoimidazole-4(5) carboxamide or vehicle (phosphate buffered saline). They were exposed to a 3.5 h A/R stress, reoxygenated and switched to a 10S10Y diet. Survival was measured after 2 days. Sample sizes (starved, fed) are indicated in parentheses. § p<0.01 as compared to flies treated with the vehicle only and p<0.05 as compared to flies treated with the inactive compound. §§ p<0.01 as compared to the two other conditions. B. Rapamycin does not modify the anoxic tolerance. Flies were maintained for 2 days on a 1S1Y or a 10S10Y diet supplemented with 100 µM rapamycin or vehicle (1% ethanol). They were exposed to a 3.5 h A/R stress, reoxygenated and switched to a 10S10Y diet. Survival was measured after 2 days. Sample sizes (starved, fed) are indicated in parentheses. Mortalities of rapamycin treated flies were not different from those of controls. Low concentrations of ethanol (1%) reduced the survival of starved A/R stressed flies probably by providing calories to the flies and by reducing the strength of dietary restriction. C. Resveratrol does not modify the anoxic tolerance. Flies were maintained for 2 days on a 1S1Y or a 10S10Y diet supplemented with 100 µM resveratrol or vehicle (1% dimethylsulfoxide). They were exposed to a 3.5 h A/R stress, reoxygenated and switched to a 10S10Y diet. Survival was measured after 2 days. Sample sizes (starved, fed) are indicated in parentheses. Mortalities of resveratrol treated flies were not different from those of controls. Low concentrations of dimethylsulfoxide (1%) reduced the survival of starved A/R stressed flies for unknown reasons. D, E, F. Food intakes by flies fed on AICAR or 5(4)-Aminoimidazole-4(5) carboxamide (D), rapamycin (E) and resveratrol (F). Drugs were used at a concentration of 100 mM. Controls were performed using corresponding vehicles. All solutions were supplemented with 5% sucrose. Means±sem are indicated (n = 4–7). ** p<0.01 as compared to vehicle, ns: not statistically different.</p

Anoxia tolerance, locomotor activity and stupor recovery.

<p>A, B. Feeding flies on a poor diet increases their locomotor activity. A. Schematic representation of the locomotor activity assay (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0005422#s4" target="_blank">Material and Methods</a>). B. Escape rates. N = 100 under the two conditions. C. Development of anoxic stupor. Male w¹¹¹⁸ flies adapted for 2 days to a 1S1Y diet (red, n = 96) or a 10S10Y diet (blue, n = 102) were exposed to anoxia and the time required for each individual fly to fall into stupor was recorded. P = 0.0026 using the log rank test. The time required to decrease oxygen tension to <0.1% was 3 minutes. D. Recovery from anoxic stupor. Male w¹¹¹⁸ flies adapted for 2 days to a 1S1Y diet (red, n = 136) or a 10S10Y diet (blue, n = 133) were exposed to a 1 h anoxia and reoxygenated. The time required to resume a walking activity was measured. P = 0.04 using the log rank test.</p