Avoiding the potential pitfalls of using negative priming tasks in developmental studies: Assessing inhibitory control in children, adolescents, and adults.

Despite being ignored, visual distractors often produce traceable negative priming (NP) effects that can be used to investigate inhibitory processes. Robust NP effects are typically found with young adults, but not with children. Using 2 different NP tasks, the authors compared NP in 5 different age groups spanning 5 to 25 years of age. The 1st task revealed comparable NP between all age groups, but a linear decrease in NP through childhood to early adulthood. In the 2nd task, NP decreased linearly into adulthood, with children actually showing larger NP than adults. This Age Group ? NP interaction was eliminated, however, when reaction time data were log transformed to control for age differences in overall processing speed. When appropriately transformed data were used, both experiments showed that NP was intact and comparable between children, adolescents, and adults, and suggested that an inhibitory process is fully developed by early childhood. The results highlight how potential pitfalls might be avoided when comparing NP in children and adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Spatial Extension to the π Calculus

Spatial dynamics receive increasing attention in Systems Biology and require suitable modeling and simulation approaches. So far, modeling formalisms have focused on population-based approaches or place and move individuals relative to each other in space. SpacePi extends the π calculus by time and space. π processes are embedded into a vector space and move individually. Only processes that are sufficiently close can communicate. The operational semantics of SpacePi defines the interplay between movement, communication, and time-triggered events. A model describing the phototaxis of the Euglena micro-organism is presented as a practical example. The formalism's use and generality is discussed with respect to the modeling of molecular biological processes like diffusion, active transportation in cell signaling, and spatial structures.     

Influence of reactant characteristics on the microstructures of combustion-synthesized titanium carbide

The influence of reactant characteristics on morphological development through the stages of combustion synthesis was investigated using a titanium-carbon system. The effect of the characteristics of a variety of carbons (carbon blacks, graphites, and cokes) and a variety of titanium powders on the density and microstructure of combusted and uncombusted sample compacts was studied. The size of the titanium particles had a relatively small influence on the density of the final (TiC) product but had a significant effect on its microstructure. The structure of the carbon blacks (as judged by the n-dibutyl phthalate absorption number, DBP) had a direct influence on the density of the uncombusted and combusted samples: low-structure carbon blacks resulted in higher densities for both cases. Products made with natural graphites had higher densities than those made with synthetic graphites. The surface area of carbon and graphite reactant powders had less influence on the density of the product than on its network morphology. Cored structures in TiC products made from certain carbon and graphite powders were observed and are explained in terms of their ash (oxide) content.     

Zeitlicher Druckverlauf bei Explosionen als Grundlage zur Auslegung von Behältern und Apparaten

Time-dependent behaviour of pressure in cases of explosions: A basis for design of pressure vessels and apparatus . The knowledge of the maximum explosion pressure is important for design of pressure vessels subject to danger of explosion. Especially for non-spherical geometries or plant-internal pressure relief, the maximum explosion pressure has to be calculated from the time-dependent pressure caused by a chemical reaction in the vessel. Therefore, a set of ordinary differential equations was solved numerically by means of the method of differences. Examples are drawn from known experimental studies. Turbulence effects are also considered. As a result, an analytical relationship is derived which gives the necessary pressure relief area. Finally the results are compared with those of available formulas. Deviations are explained in detail.     

Formation and properties of magnesium–ammonium–phosphate hexahydrate biocements in the Ca–Mg–PO<Subscript>4</Subscript> system

Calcium substituted trimagnesium phosphate with the general formula Ca_xMg_(3−x)(PO₄)₂ (0 < x < 1.5) was synthesized by calcination of powder mixtures with the appropriate stoichiometry and reacted with 3.5 M diammonium hydrogenphosphate solution to form a cementitious matrix of magnesium ammonium phosphate hexahydrate (struvite). The degree of ionic substitution was shown to influence physical cement properties; clinically suitable cement formulations with setting times in the range 5–15 min and compressive strengths of >50 MPa were obtained for x ≤ 0.75 together with a grinding time ≥1 h and a powder to liquid ratio ≥2.5 g/ml. The cement cytocompatibility was investigated by culturing human osteoblast cell line MG63 on cement surfaces demonstrating pronounced cell growth during 13 days cultivation.     

Theoretical principles for the indirect determination of the total glucosinolate content in rapeseed and meal quantifying the sulphur concentration via X-ray fluorescence (X-RF method)

The introduction of double low oilseed rape cultivars into common crop production will require the development of methods for a precise, rapid and simple determination of the total glucosinolate content in rapeseed. Recent methods are often inappropriate for plant breeding work, and also for the trade and oil mills in separating parcels of seed according to their glucosinolate contents. In contrast to the methods commonly used (chromatography, enzymic and colorimetric tests) an indirect method is described here which is based on the very close correlation between the total sulphur and glucosinolate content in rapeseed. The sulphur content of the samples can be determined precisely and non-destructively by means of X-ray fluorescence spectroscopy (X-RF). This new method, which is suitable for rapeseed and meal, requires simple preparation of the seed samples by grinding and compressing. The whole analytical procedure (sample preparation and measurement) takes 2-4 min. If necessary, moist seed samples can be quickly dried by microwave heating, because the method does not require intact glucosinolates. The steps of the X-RF method are fairly insensitive to errors. The method shows an excellent repeatability (r = 1.9 μmol g^?1) and reproducibility (R = 3.8 μmol g^?1). The results obtained with this X-RF method correlate closely with the conventional reference methods (r² = 96-99%).     

Structural and functional characteristics of muscle fibres in pigs with different malignant hyperthermia susceptibility (MHS) and different meat quality

In pigs, intensive growth of the musculature is often accompanied by malignant hyperthermia susceptibility (MHS; n gene) and poorer meat quality. Using histological and histochemical methods, different fibre characteristics in the Longissimus muscle were found in Pietrain×German Landrace pigs with this gene defect. Compared to MHS homozygous negative pigs, groups with the n gene had increased diameters of the mean fibre types and increased glycolytic metabolic potential, as shown by a higher frequency of the fast twitch glycolytic type and a lower frequency of the slow twitch oxidative fibre type. Differences between the groups were also found in the number of angular and giant fibre types. Furthermore, a positive correlation was found between the frequency of oxidative fibres and the relative enzyme activity of NADH tetrazolium reductase. The changes correlated with lower pH and higher drip loss in meat from the MHS homozygous positive group. In conclusion, the different muscle fibre characteristics can be interpreted as endogenous factors which influence the physiological condition in the muscle of the live animal and meat quality post mortem.     

Acceptability of lamb meat from different producing systems and ageing time to German, Spanish and British consumers

In the present study German (DE), Spanish (ES) and British (UK) consumers' acceptance of lamb from their own country compared to lamb from Uruguay (UY) was evaluated. Two-hundred consumers in each country evaluated tenderness, flavour and overall acceptability of four types of lamb, two from UY (light and heavy lambs aged 20 d) and 2 local (with two ageing times, 7 and 20 d). In each country 1.5cm-thick slices of lamb were evaluated by previously selected consumers in controlled conditions. DE and UK consumers showed significantly (P<0.05) different acceptability scores between samples, the lamb from heavier animals and aged 20 d being the most appreciated. On the other hand the majority of the ES consumers significantly (P<0.05) preferred the meat from lighter lambs. Production systems, cultural aspects and consumption habits seem to affect the acceptability of the lamb to the consumers.     

Eating quality of beef, from different production systems, assessed by German, Spanish and British consumers

The acceptability of beef from Uruguay (UY), based on eating quality, was compared with beef produced in different European countries (Germany, DE, Spain, ES and United Kingdom, UK). Consumer tests were conducted in DE, ES and UK (each comprising 200 consumers) using 'Hall Tests'. In each country four samples were evaluated, two from Hereford steers from UY (finished at 2 and 3 years) and two from local meat (the same meat sample aged 7 or 20d). Consumers evaluated tenderness, flavour and overall acceptability using 8-point category scales. Hierarchical cluster analysis, highlighted the existence of different clusters of consumers. Two main clusters were identified in DE and UK. The main cluster identified in DE, was labelled as Prefer foreign-imported beef (n=128). These consumers preferred (P<0.05) the samples from UY_2y in terms of tenderness and overall acceptability. The other cluster was labelled as Prefer local beef in terms of flavour and overall acceptability (P<0.05) and comprised the majority of consumers from ES (n=176) and UK (n=153) and the cluster 2 from DE (n=69). UK, cluster 2 (n=33) that did not discriminate between origin and ageing time of beef. These results indicate that consumers did not prefer the same type of meat within the same country and it is possible that there are individual preferences that could lead to the concept of market segmentation being based on taste preferences. It would appear that Uruguayan beef would be very acceptable in Germany and to a lesser extent in Britain and Spain, although further studies are required that include labelling information.     

Polarization and phase control of remote surface-plasmon-mediated two-photon-induced emission and waveguiding

We report here on the control of remote surface-plasmon-mediated two-photon-induced luminescence of dendritic silver nanoparticle aggregates as observed by femtosecond laser microscopy. With a focal spot diameter approximately 1 microm, polarized remote emission has been observed 99 microm from the focal spot. We show control over the regions of emission by changing the polarization of the incident beam and by changing the spectral phase of the laser pulse.