Improvements in Spelling after QEEG-based Neurofeedback in Dyslexia: A Randomized Controlled Treatment Study

Phonological theories of dyslexia assume a specific deficit in representation, storage and recall of phonemes. Various brain imaging techniques, including qEEG, point to the importance of a range of areas, predominantly the left hemispheric temporal areas. This study attempted to reduce reading and spelling deficits in children who are dyslexic by means of neurofeedback training based on neurophysiological differences between the participants and gender and age matched controls. Nineteen children were randomized into an experimental group receiving qEEG based neurofeedback (n = 10) and a control group (n = 9). Both groups also received remedial teaching. The experimental group improved considerably in spelling (Cohen’s d = 3). No improvement was found in reading. An indepth study of the changes in the qEEG power and coherence protocols evidenced no fronto-central changes, which is in line with the absence of reading improvements. A significant increase of alpha coherence was found, which may be an indication that attentional processes account for the improvement in spelling. Consideration of subtypes of dyslexia may refine the results of future studies.     

The role of the conversion of IBA into IAA on root regeneration in apple: introduction of a test system

A test system for root regeneration was developed that consists of stem slices of apple shoots (ca. 0.5 mm thick; fresh weight ca. 1 mg). Roots regenerated synchronously without intervening callus formation and without interference with compounds originating from other parts of the plant. Supply of indolebutyric acid (IBA) or indoleacetic acid (IAA) induced maximally an average of 8 or 4.5 roots per slice, respectively. After uptake of IBA, a high degree of conjugation resulted in a recovery of 2.5% as internal free IBA (ca. 2 times the medium concentration). Due to conversion of absorbed IBA into IAA a fraction of 0.4% was recovered as (physiologically active) free IAA. After incubation on medium with IAA, 0.5% of the absorbed hormone was recovered in the free acid form. No conversion of IAA into IBA was observed. Equimolar contents of internal free IAA after incubation on IBA or IAA resulted for IBA in a higher number of roots than for IAA. This means that IBA may also act via internal free IBA or may synergistically modify the action or endogenous synthesis of IAA.Abbreviations BHT butyl hydroxy toluene - EtOH ethanol - FW fresh weight - HAc acetic acid - HPLC high performance liquid chromatography - IAA indoleacetic acid - IAA^int free (internal) IAA in the tissue derived from IBA or IAA uptake - IBA indolebutyric acid - IBA^int free (internal) IBA in the tissue derived from IBA or IAA uptake - MeOH methanol - PAR photosynthetic active radiation - SEM standard error of the mean - TLC thin layer chromatography - UV ultra violet     

Undertreatment of hypertension and the risk of stroke in the oldest old

The benefit of pharmacological treatment of hypertension in the prevention of cardiovascular diseases has been established mainly in subjects younger than 80 years of age. The consequences of undertreatment of hypertension with regard to the occurrence of stroke was studied in the Netherlands. About 33% of the hypertensives younger than 80 years and 55% of the hypertensives older than 80 years were not pharmacologically treated, although they were 'candidates' for pharmacological treatment of hypertension. About 19% (n = 1350) of all strokes that occurred in the Netherlands in 1994 among hypertensives younger than 80 years may be attributable to untreated hypertension. Among hypertensives older than 80 years this percentage was 32% (n = 1345). Although the benefit of pharmacological treatment of hypertension in persons older than 80 years has not been established experimentally, the results suggest that a considerable proportion of the strokes among this group of hypertensives may be prevented.     

Microelectronic detection of activity level and magnetic orientation of yellow European eel, <Emphasis Type="Italic">Anguilla anguilla</Emphasis> L., in a pond

Synopsis We studied the circadian and monthly activity, the distribution patterns, and orientation to the earths magnetic field, of yellow (non-migratory) female eels in a freshwater pond by means of microchips injected into their muscles. Detectors for microchips mounted in tubes were placed in the pond to detect if eels oriented themselves with respect to earths magnetic field. Based on the frequency of tube visits (search for shelter), the data indicated that the presence of eel in the tubes decreases gradually during the study period. We saw more activity during the night in the first months. There was a seasonal component in the orientation mechanism, with a significantly lower preference component in the summer compared to the fall. A preference for tubes oriented in a south-southwest direction (the direction of the Sargasso Sea) in fall suggests an orientation to the earths magnetic field.     

Breeding pelagic copepods

Summary A cultivation technique has been developed to breed marine pelagic copepods for experimental purposes. Heterotrophic dinoflagellates occurring in the copepod cultures prevent the cultures from fouling due to sedimentation of autotrophic algae, administered daily from continuous cultures. The dinoflagellates keep themselves well in suspension, consume any excess of algae and dead organic material, and, importantly, appear to be an excellent food for the copepods (KLEIN BRETELER, 1980).At presentPseudocalanus elongatus, Acartia clausi, Centropages hamatus andTemora longicornis have been bred through 10, 11, 33, and 35 filial generations, respectively, and are still breeding continuously. Growth rate and isochronal development were dependent on both the concentration of food and the presence of dinoflagellates.     

Selective grazing of Temora longicornis in different stages of a Phaeocystis globosa bloom—a mesocosm study

Selective grazing of a calanoid copepod Temora longicornis was measured during different stages of a Phaeocystis globosa bloom, in order to reveal (1) if T. longicornis feeds on single cells and/or colonies of P. globosa in the presence of alternative food sources, (2) if copepod food selection changes during the initiation, maintenance, collapse and decay of a P. globosa bloom and (3) if P. globosa dominated food assemblage provides a good diet for copepod egg production. Our results show low but constant feeding on small colonies of P. globosa, irrespective of the type or concentration of alternative food sources. In contrast, feeding on single cells was never significant, and the total contribution of P. globosa to carbon ingestion of T. longicornis was minor. T. longicornis fed most actively on the decaying colonies, whereas during the peak of the bloom copepods selected against P. globosa. Mostly, T. longicornis fed unselectively on different food particles: before the bloom, the major part of the diet consisted of diatoms, whereas during and after the bloom copepod diet was dominated by dinoflagellates and ciliates. Egg production was highest during the decay of the bloom, coinciding with highest proportional ingestion of heterotrophic organisms, but was not seriously reduced even during the peak of the bloom. We conclude that P. globosa blooms should not threaten survival of copepod populations, but the population recruitment may depend on the type (and concentration) of the dominant heterotrophs present during the blooms. Due to relatively unselective grazing, the impact of T. longicornis to the initiation of a Phaeocystis bloom is considered small, although grazing on decaying colonies may contribute to the faster termination of a bloom.     

A synopsis of <Emphasis Type="Italic">Casearia</Emphasis> Jacq. (<Emphasis Type="Italic">Samydeae – Salicaceae</Emphasis>) in West and Central Africa with a description of a new species from Eastern Congo (Kinshasa)

Summary  Sleumer’s (1971) revision of Casearia (formerly Flacourtiaceae, now Salicaceae) is reviewed to correct the specific delimitation, nomenclature and geography of some of the West and Central African species. As a result, Casearia inaequalis Hutch. & Dalz. and C. prismatocarpa Mast. are resurrected, the latter to replace C. calodendron Gilg ex Engl. Casearia michelsonii, from the mountains of East Congo (Kinshasa), is described as new. A revised key to the species of West and Central Africa is presented and their distributions are mapped.     

Influence of temperature and food concentration on body size,weight and lipid content of two Calanoid copepod species

Two species of Copepoda Temora longicornis (Müller) and Pseudocalanus elongatus (Boeck) were cultured continuously in the laboratory. Four and three generations, respectively, were raised at 16 different combinations of temperature and food concentration. Prosome length and ash-free dry weight were measured in the adult stage and in Pseudocalanus also in copepodite stage I, and the relation between length and weight was established. In Pseudocalanus also the relative amount of lipid was estimated.Prosome length and length-specific body weight (condition factor) were positively correlated with food concentration. Lipid content in Pseudocalanus was also strongly affected by the concentration of food.Prosome length was negatively correlated with temperature. However, length-specific body weight in Temora was positively correlated with temperature. Therefore, at higher temperature Temora was smaller, but heavier per unit body length. In Pseudocalanus a similar but less significant influence of temperature on length-specific weight was found; lipid content was not significantly influenced by the temperature.Females of Temora had larger length-specific weights than males. In Pseudocalanus the opposite was found, coinciding with a higher lipid content in males than in females.It is discussed that at natural concentrations of phytoplankton body size and weight of copepods are reduced in the North Sea during the major part of the growing-season.     

Colonization of the root zone ofAmmophila arenaria by harmful soil organisms

The role of harmful soil organisms in the degeneration ofAmmophila arenaria at coastal foredunes was examined by the growing of seedlings ofA. arenaria in soil samples collected from its root zone. Three sites, each representing a successive stage in foredune succession were examined: (1) a highly mobile dune (sand accretion of 80 cm year⁻¹) with vigorousA. arenaria, colonizing only the upper 30-cm of the annually deposited layer of sand, (2) a mobile dune with vigorousA. arenaria (sand accretion of 22 cm year⁻¹) and a 1-metre soil profile completely colonized by roots and (3) a stable dune (no sand accretion) with degeneratedA. arenaria and young roots mainly present in the upper 0–10 cm. In the upper part of the highly mobile site, the presence of harmful soil organisms was confined to the root layers and at the mobile site for all depth layers a significant growth reduction ofA. arenaria was observed due to the activity of harmful soil organisms. At the stable site, however, growth had only been reduced in some of the depth layers. At all sites newly formed roots ofA. arenaria had been colonized by harmful soil organisms within one year. If present in sand prior to root growth harmful soil organisms reduced root length and root hair formation severely and they enhanced branching of the roots. It is concluded that harmful soil organisms initiate degeneration ofA. arenaria in stable dunes by attack of the root system, which makes the plants suffer from abiotic stress.