Study of the nutrient distribution in root tips of the tropical forage Brachiaria

A Brachiaria breeding project is being conducted at CIAT, Colombia to combine acid soil adaptation of B. decumbens with other favourable traits of Brachiaria species that are less adapted to acid soils. Micro-PIXE was applied to investigate nutrient uptake and distribution in root tips of different species grown in hydroponic culture under control and simulated acid soil stress conditions. Different sample measurement approaches were evaluated, including: (1) linear scans with single point measurements along the root axis; (2) mapping of whole root tips; and (3) mapping of root cross sections. Different tissue types could be distinguished on the base of differences in nutrient concentrations and/or Al stress. Al, if supplied under nutrient stress conditions, increased P accumulation in the central vascular tissue of the meristematic and elongation zone of B. decumbens and B. brizantha. Furthermore, a negative correlation was found between Al and Cl accumulation in the root cap of B. decumbens.     

Numerische Simulation der Faserbewegung beim Strangpressen kurzfaserverstärkter Glasschmelzen

Numerical Simulation of the Fibre-Motion during the Extrusion of Short-Fibre-Reinforced Glass-Melts Fibre-reinforced materials are characterized by an anisotropic behaviour of the mechanical properties, which is caused by the alignment of the embedded fibres. In the case of short-fibre-compounds this behaviour is strongly influenced by the mechanism of flow during the manufacturing process. Numerical simulation Methods are preferentially used to get informations about the orientation of the reinforced fibres at the end of the molding-process and to improve the properties of the compound. For that, a model is developed, which calculates the motion of the short-fibres in the area of flow, basing on a three-dimensional finite-element-computation. Thereby the interaction between the Particular fibres during the orientation process is considered by using an interaction coefficient. Examplified at the extrusion of short fibre reinforced glass-melts, the fibre orientation is determined at models with different geometries of the pressing tool and variable boundary conditions. This procedure allows to determine the influence of the process-parameters On the expected quality of the composite. The represented simulation-model can also be used for other molding- and extrusion-processes of fibre reinforced materials.     

Ermüdungsverhalten und Dauerfestigkeit von Graphit und Aluminium – infiltriertem Graphit

Fatigue behaviour and endurance limit of graphite and of aluminium‐infiltrated graphite Fatigue properties of polycrystalline, isotropic graphite FU2590 and of FU2590 infiltrated with AlSi7Mg (FU2590/AlSi7Mg) were investigated in reversed bending tests at 25 Hz at numbers of cycles below 10⁷ and in tension‐compression tests at 20 kHz below 10⁹ cycles. The open porosity of Graphite (10‐11 Vol.‐%) was infiltrated with the aluminium alloy using the squeeze casting infiltration method, which led to an increase of the bending strength by 50 %, increase of tensile strength by 30 % and increase of stiffness by 15 %. Fully reversed tension‐compression loading of FU2590 delivers a mean endurance limit at 10⁹ cycles at the normalized maximum stresses (i.e. maximum tension stress of a cycle divided by the static strength) of 0,65±0,03. Mean numbers of cycles to failure of 10⁴ were found in fully reversed bending tests at the normalized maximum stress of 0,78. The infiltrated material shows approximately 30 % higher cyclic strength in reversed bending tests, and the mean endurance limit under tension compression loading increases by 15 %. The increased endurance limit of the infiltrated material is caused by the increased stiffness. The increased toughness of graphite due to the infiltration with aluminium is of additional beneficial influence at the higher cyclic stresses investigated in reversed bending tests and in static tests.     

Reading epilepsy: report of five new cases and further considerations on the pathophysiology

Liposomes, microscopic lipid vesicles consisting of concentric phospholipid bilayers enclosing discrete aqueous spaces, have been investigated extensively as carries for drugs in attempts to achieve selective deposition and/or reduced toxicity. Liposomes radiolabeled with gamma emitters (67Ga, 111In and 99mTc) have been used for imaging purposes. Liposomes as formulated in the past, are rapidly taken up by cells of the mononuclear phagocyte system, primarily those located in liver and spleen. However, it has been shown during the last two decades that the in vivo behavior of liposomes can be modulated by modifying their formulation. The size and the lipid composition have a major influence on the blood clearance rate, hepatic uptake and splenic uptake of liposomes. The development of long circulating liposomes, in particular coating of the bilayer with polyethyleneglycol (PEG) resulted in liposomes that oppose recognition by the MPS, thus displaying even longer circulatory half-lives. By carefully adjusting the liposomal formulation, the in vivo characteristics of liposomes can be tailored such that they become suitable vehicles for imaging various pathological processes in vivo. Liposomes have been proposed for tumor imaging, for infection imaging and as blood pool markers. Here, the factors that determine the in vivo behavior of liposomes and the current status of liposome-based radiopharmaceuticals are reviewed.     

Cognitive consequences of making computer-based learning activities more game-like

Some students (base group) played the Circuit Game, a 10-level computer-based learning activity intended to help students learn how electrical circuits work. Other students (competition group) played the same game but with competition features added - including a score bar showing performance on each level, the opportunity to earn one ticket per level if a performance criterion is met, and the opportunity to win a prize based on the number of tickets earned. On a retention test given after the game, the competition group remembered significantly more than the base group (d = 0.47). On an embedded transfer test constituting the final level of the game, the groups did not differ significantly. However, on the transfer test there was a significant gender by group interaction in which men performed worse in the competition group than the base group (d = −0.54) and women performed better in the competition group than the base group (d = 0.24). Overall, adding game-like features to a computer-based learning activity caused students to pay attention to game details but did not motivate students - particularly men - to learn more deeply.     

A Discrepancy in Analyses of the MSCEIT--Resolving the Mystery and Understanding Its Implications: A Reply to Gignac (2005).

Replies to comments made by G. E. Gignac (see record 2005-06671-010) on the current authors' original article (see record 2003-02341-015). Gignac reanalyzed the factor structure of the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) and found results that differed from those the authors obtained initially. The authors tracked down the surprising sources of those discrepancies. G. E. Gignac's hierarchical model of emotional intelligence appears promising, and the authors anticipate that further investigations of the MSCEIT factor structure may yield additional information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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