To what extent does bilingualism affect children's performance on the NEPSY?

Twenty-seven monolingual and 27 bilingual children aged between 6 and 7 years were assessed using the core subtests of the NEPSY, a children's neuropsychological assessment. Bilingual children scored lower than monolingual children in the Language domain and their performance was comparable with the monolingual children in the domains of Attention/Executive Functioning, Sensorimotor, Visuospatial, and Memory. The NEPSY correlates well with measures of academic achievement. It is concluded that the NEPSY is relatively insensitive to cultural factors and appears to be insensitive to bilingualism in the neuropsychological assessment of bilingual children in the United Kingdom.

Ultrasound-induced physiological changes in cultured cells of Petunia hybrida.

Petunia hybrida cell suspension cultures were exposed to ultrasonic standing wave fields at 2.43 MHz for 40 min with mean sound pressures (within homogenous sound fields) varying from 0 (control) to ca. 1.1 MPa. Mean (+/- s.d.; n =6-9) cell viability was reduced to 87+/-10% at 0.6 MPa and to 59 +/- 23% at 1.1 MPa, compared to an initial control value of 92 +/- 6% (P <0.05). Mean (n = 3) cell alkaline phosphatase concentration increased linearly with sound pressure from a control value of 0.006+/-0.001 to 0.02+/-0.01 Sigma-Units microg(-1) protein at 1.1 MPa (P<0.05). Similarly, mean cell catalase activity increased from a control value of 0.020 +/- 0.003 to 0.026 +/- 0.008 arbitrary units at 1.1 MPa. In contrast, mean cellular lactate dehydrogenase concentration was unchanged. These observations indicate that cellular repair processes associated with increased alkaline phosphatase activity might be triggered by physical cell damage caused by ultrasound. The observed increase in catalase activity suggests increasing production of free radicals and other sonochemicals, which warrants further study. The absence of changes in lactate dehydrogenase indicates that there was no major damage to respiratory pathways or to overall cellular integrity.

Hemoglobin-stimulated growth and antioxidant activities in cultured cotton cells.

Changes in cellular reactive oxygen scavenging enzymes were assessed in suspension-derived cells of cotton (Gossypium herbaceum) cv. Dhumad following culture with a commercial bovine hemoglobin (Hb) solution (Erythrogen) at 1:100-1:1000 (v:v). Mean (+/- SEM) fresh (f.wt.) and dry weights (d.wt.) of cells after 25 d of culture were significantly (p <.05) greater in medium supplemented with 1:750 and 1:1000 (v:v) Erythrogen, compared to controls lacking Erythrogen. For example, with 1:750 (v:v) Erythrogen, mean cell f.wt. and d.wt. were increased by 45 and 31%, respectively. Total soluble cellular protein increased by 141, 176, and 191% with Erythrogen at 1:50, 1:750, and 1:1000 (v:v), respectively. Cellular catalase and glutathione reductase activities decreased significantly (p <.05) following addition of low concentrations (1:1000 and 1:750 v:v) of Erythrogen to culture medium. However, increasing the concentration of Erythrogen to a maximum of 1:100 (v:v), caused a concomitant increase in catalase to a maximum of 62% over control. Mean total superoxide dismutase activity increased linearly with increasing Erythrogen concentration, reaching a maximum mean value over 2-fold greater than control with 1:100 (v:v) Erythrogen. A similar trend was observed in cellular H2O2 content, which reached a maximum of 98% over control with 1:250 (v:v) Erythrogen. These results demonstrate that culture of cotton cells with Hb solution causes changes in cellular oxygenation sufficient to modify cellular antioxidant status.

Effects of P(SAG12)-IPT gene expression on development and senescence in transgenic lettuce.

An ipt gene under control of the senescence-specific SAG12 promoter from Arabidopsis (P(SAG12)-IPT) significantly delayed developmental and postharvest leaf senescence in mature heads of transgenic lettuce (Lactuca sativa L. cv Evola) homozygous for the transgene. Apart from retardation of leaf senescence, mature, 60-d-old plants exhibited normal morphology with no significant differences in head diameter or fresh weight of leaves and roots. Induction of senescence by nitrogen starvation rapidly reduced total nitrogen, nitrate, and growth of transgenic and azygous (control) plants, but chlorophyll was retained in the lower (outer) leaves of transgenic plants. Harvested P(SAG12)-IPT heads also retained chlorophyll in their lower leaves. During later development (bolting and preflowering) of transgenic plants, the decrease in chlorophyll, total protein, and Rubisco content in leaves was abolished, resulting in a uniform distribution of these components throughout the plants. Homozygous P(SAG12)-IPT lettuce plants showed a slight delay in bolting (4-6 d), a severe delay in flowering (4-8 weeks), and premature senescence of their upper leaves. These changes correlated with significantly elevated concentrations of cytokinin and hexoses in the upper leaves of transgenic plants during later stages of development, implicating a relationship between cytokinin and hexose concentrations in senescence.