Brain-potential evidence for the time course of access to biographical facts and names of familiar persons.

On seeing familiar persons, biographical (semantic) information is typically retrieved faster and more accurately than name information. Serial stage models explain this pattern by suggesting that access to the name follows the retrieval of semantic information. in contrast, interactive activation and competition (IAC) models hold that both processes start together but name retrieval is slower because of structural peculiarities. With a 2-choice go/no-go procedure based on a semantic and a name-related classification, the authors tested differential predictions of the 2 alternative models for reaction times (RTs) and lateralized readiness potentials (LRP). Both LRP (Experiment 1) and RT (Experiment 2) results are in line with IAC models of face identification and naming. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Detailed Structure–Function Correlations of Bacillus subtilis Acetolactate Synthase

Isobutanol is deemed to be a next‐generation biofuel and a renewable platform chemical. 1 Non‐natural biosynthetic pathways for isobutanol production have been implemented in cell‐based and in vitro systems with Bacillus subtilis acetolactate synthase (AlsS) as key biocatalyst. 2 – 6 AlsS catalyzes the condensation of two pyruvate molecules to acetolactate with thiamine diphosphate and Mg²⁺ as cofactors. AlsS also catalyzes the conversion of 2‐ketoisovalerate into isobutyraldehyde, the immediate precursor of isobutanol. Our phylogenetic analysis suggests that the ALS enzyme family forms a distinct subgroup of ThDP‐dependent enzymes. To unravel catalytically relevant structure‐function relationships, we solved the AlsS crystal structure at 2.3 Å in the presence of ThDP, Mg²⁺ and in a transition state with a 2‐lactyl moiety bound to ThDP. We supplemented our structural data by point mutations in the active site to identify catalytically important residues.     

Loss of nitrogen from urea applied to rainfed wheat in varying rainfall zones in northern Syria

Fertilizer-applied Nitrogen (N) may be lost from the soil by various mechanisms, i.e., runoff, leaching, denitrification, and volatilization. The latter process is of primary concern in calcareous soils of arid and semi-arid regions, especially when urea is used. In this field study from northern Syria, urea alone, urea with either an incorporated urease inhibitor, phenylphosphorodiamidate, or an experimental bran-wax coating were evaluated on wheat for two cropping seasons at two experimental stations with varying average seasonal rainfall (340 mm, 270 mm). Loss of N was assessed with ¹⁵N by mass balance, i.e., the amount of N applied minus the crop N uptake and N remaining in the soil. Crop yields and N uptake were related to seasonal rainfall. Losses of N, apparently as volatilized NH₃, were relatively low at both sites, i.e., 11–18%. However, compared to the unmodified urea, neither the incorporated urease inhibitor nor the bran-wax coating had any effect on yields, N uptake or N loss. While urea hydrolysis is normally rapid, it may be delayed by dry conditions at the soil surface; similarly, unusually cold periods may delay nitrification following hydrolysis. Thus, under the cool-season conditions of rainfed cropping in the Middle East, efficient use of urea is not likely to be achieved by modification of the urea but by conventional management practices that ensure pre-plant soil incorporation or topdressing during early spring rains.     

Structural invariance and age-related performance differences in face cognition.

Perceiving and memorizing faces swiftly and correctly are important social competencies. The organization of these interpersonal abilities and how they change across the life span are still poorly understood. We investigated changes in the mean and covariance structure of face cognition abilities across the adult life span. A sample of 448 participants, with age ranging from 18 to 88 years, completed a battery of 15 face cognition tasks. After establishing a measurement model of face cognition that distinguishes between face perception, face memory, and the speed of face cognition, we used multiple group models and age-weighted measurement models to explore age-related changes. The modeling showed that the loadings and intercepts of all measures are age invariant. The factor means showed substantial decrements with increasing age. Age-related decrements in performance were strongest for the speed of face cognition but were also salient for face perception and face memory. The onset of age decrements is apparent in the 60s for face perception, in the late 40s for face memory, and in the early 30s for speed of face cognition. Implications of these findings on a theoretical and methodological level are discussed, and potential consequences for applied settings are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do as your parents say?—Analyzing IT adoption influencing factors for full and under age applicants

The article suggests a model for examining the adoption of e-recruiting by individuals. The model is empirically evaluated using survey data from 323 full and under age applicants. The results explain substantial parts of the individual adoption decision. Interestingly, the relative importance of the adoption drivers varies with age, social environment and the level of education. While, as expected, overall Performance Expectancy is the major force behind adopting e-recruiting, the relative importance of the other factors differs a lot. Whereas Facilitating Conditions came out as an important driver for under age pupils, full age students by contrast are highly driven by the influence of their peer groups and the communication of the respective company they apply for. A major outcome is that the Subjective Norm of family and friends, teachers and professors has a weaker influence for under age pupils who mostly live with their parents than for the group of students who already left home to study at college. Consequentially we assume that the social influence of peer groups on an individual’s adoption differs with respect to age, social environment and level of education. This should be investigated more carefully in future adoption research as it might provide an answer for the varying significance of Subjective Norm in adoption research.     

Regelung nichtlinearer strecken mittels linearer parameterveränderlicher systeme

übersicht Es wird vorgeschlagen, den Reglerentwurf für nichtlineare Strecken auf die Synthese an Linearen parameterver?nderlichen Systemen (LPV-Systemen) zurückzuführen. Dies ist dann m?glich, wenn es gelingt ein nichtlineares Streckenmodell so umzuformen, da? es als LPV-System betrachtet werden kann. Diese Umformung geschieht hier mit Hilfe einer nichtlinearen Zustandstransformation. Als LPV-Entwurfsverfahren wird die Self-scheduled H _∞ -Regelung herangezogen. Die Demonstration der Strategie erfolgt an einem Beispiel.

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Contents We present a new approach to reduce the controller design for general nonlinear plants to Linear parameter-varying systems (LPV-systems). Therefore we model a class of nonlinear systems as LPV system via a nonlinear state-transformation. This practise allows us to use LPV-controller design methods. In this article we apply Self-scheduled H _∞ -control. The proposed conception will be demonstrated on an example.

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Eingegangen: 9. Juli 1999     

Lidocaine-loaded biodegradable nanospheres. I. Optimization Of the drug incorporation into the polymer matrix

Spherical nanoparticulate drug carriers made of poly(d,l-lactic acid) with controlled size were designed. A local anesthetic, lidocaine, a small hydrophobic molecule, was incorporated in the core with loadings varying from about 7 to 32% (w/w) and increasing with the particle size. Particles with sizes from about 250 to 820 nm and low polydispersity were prepared with good reproducibility; the polymer concentration (at constant surfactant concentration) governed the particle size. The large particles with a high loading ( approximately 30%) showed under in vitro conditions a slow release over 24-30 h, the medium sized carriers (loading of approximately 13%) released the drug over about 15 h, whereas the small particles with small loading ( approximately 7%) exhibited a rapid release over a couple of hours. It seems that the drug release rate is related to the state (crystallized or dispersed) of the drug incorporated in the polymer matrix.     

Teaching a CS introductory course: An active approach

Computer Science (CS) introductory courses that are offered by the Department of Information Systems at the University of Minho (UM), Portugal, seem to abound in non-motivated students. They are characterized by high failure and withdrawal rates and use mainly deductive teaching approaches. Deductive instruction begins with theories and progresses to applications of those theories. Active approaches to teaching are more inductive. Inductive instruction begins with the presentation of, for instance, a specific problem that introduces a topic, and theories are studied on a need-to-know basis. This pilot study describes how active learning techniques have been successfully applied to a CS introductory course, reducing its failure and withdrawal rates. The study portrays the changes in the course from teacher-centered education to a learner-centered approach, using two different editions of the same course, the first one being teacher-centered and the second learner-centered. The results in terms of success, failure, and dropout are given and the impact of a more student-centered approach on student involvement in learning is analyzed. The authors discuss implications of student-centered learning for the classroom and pay attention to some of the drawbacks of an implementation more focused on active learning.     

Effect of gamma-irradiation on flavour 5′-nucleotides,tyrosine, and phenylalanine in mushrooms (Agaricus bisporus)

The impact of gamma-irradiation on 5′-nucleotides and on the free amino acids tyrosine and phenylalanine in fresh mushrooms was studied. After irradiation the samples were freeze-dried to avoid enzyme induced chemical changes. Three 5′-nucleotides could be detected using HPLC–UV and LC–ESI-MS: adenosine 5′-monophosphate (AMP), guanosine 5′-monophosphate (GMP) and guanosine 5′-diphosphate (GDP). Irradiation significantly reduced (p = 0.05) the GDP concentration (22%). AMP showed a marked reduction (46%) only at 5 kGy. GMP, tyrosine, and phenylalanine were not affected by gamma-irradiation.