Development of categorical representations for above and below spatial relations in 3- to 7-month-old infants.

A series of experiments examined the abilities of infants to form categorical representations for the spatial relations above and below. Exp 1 provided evidence that 3–4 mo olds can form categorical representations for above and below when a diamond shape was presented above or below a horizontal bar. Exps 2 and 3 showed that 3- and 4-mo olds did not form categorical representations for above and below when a number of discriminably different shapes (e.g., a diamond, a triangle, a dot) appeared above or below the bar. These more abstract categorical representations for above and below were formed by 6- to 7-mo olds (Exp 4). The findings suggest an experientially or maturationally based trend, from concrete to abstract, in the categorical representation of common spatial relations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Suboptimal exact model matching for multivariable systems withmeasurement noise

This paper describes a method for the design of discrete-time model matching control systems for a multivariable plant with measurement noise. This method uses a new parametrization for model matching controllers. Simulation results are presented which confirm the validity of the design method     

Biohydrogen production: Current perspectives and the way forward

Global research is moving forward in developing biological production of hydrogen (biohydrogen) as a renewable energy source to alleviate stresses due to carbon dioxide emissions and depleting fossil fuels resource. Biohydrogen has the potential to replace current hydrogen production technologies relying heavily on fossil fuels through electricity generation. While biohydrogen research is still immature, extensive work on laboratory- and pilot-scale systems with promising prospects has been reported. This work presents a review of advances in biohydrogen production focusing on production pathways, microbiology, as well as bioreactor configuration and operation. Challenges and prospects of biohydrogen production are also outlined.     

Healing of tibial fractures is not impaired after acute hindlimb ischemia in rats

The influence of transient circulatory arrest on the healing of closed tibial fractures was investigated in rats by the use of a hindlimb tourniquet technique. Twenty-four animals were randomly divided into three groups. In all animals, the left lower leg was fractured and fixed with an intramedullary nail system. In the ischemic group, complete acute transient ischemia for 4.5 h and neurapraxia of the sciatic and femoral nerves were induced prior to fracture. In the neurapraxia group, the sciatic and femoral nerves were crushed with forceps before fracture. In the control group, no other intervention than fracture was made. The rats of the control group ambulated normally 3-4 days after the operation. The animals of the ischemic and neurapraxia groups resumed normal weight-bearing after about 3 weeks. After 6 weeks, all animals were killed, and mechanical strength and bone mineral turnover of the healing tibia as well as blood flow of the bone and musculature were evaluated. The weight of the tibia and the corresponding anterior tibial muscle in the ischemic and neurapraxia animals were reduced compared with the control rats. Bone mineral turnover was found to be lower in the ischemic group. There were no differences between the groups in mechanical strength nor in blood circulation of bone and muscle. In conclusion, complete, acute hindlimb ischemia for 4.5 h in rats did not cause delayed healing of closed tibial fractures.     

Docosahexaenoic acid production from crude glycerol by <Emphasis Type="Italic">Schizochytrium limacinum</Emphasis> SR21

In our search for a substitute energy source, microalgal biodiesel has presented itself as a potential candidate. However, the development of biodiesel results in the overproduction of crude glycerol, which can cause undesirable environmental issues. The environmental harm can be minimized by converting crude glycerol into value-added products. One solution involves using a microalga Schizochytrium limacinum SR21 to convert crude glycerol into docosahexaenoic acid (DHA). DHA is an essential fatty acid, necessary for developing brain functions in infants and maintaining healthy brain activity in adults. In our study, the highest DHA productivity of 233.73 mg/g biomass was obtained using 3 % crude glycerol in Medium 2 at 20 °C under mixo/heterotrophic cultivation.     

Angular distribution of REC for Ar on C at 1 MeV/amu

The angular distribution of K-REC for 45.7 and 51.9 MeV Ar⁴⁺ + C has been measured and found to be consistent with sin²θ_lab.     

High drive current NMOS with Si-SiGe heterostructure low electric field channel

A drive-current enhancement in NMOS with a compressively strained SiGe structure, which had been a difficult challenge for CMOS integration with strained SiGe high-hole-mobility PMOS, was successfully achieved using a Si-SiGe heterostructure low electric field channel of optimum thickness. A 4-nm-thick Si low-field-channel NMOS with a 4-nm-thick Si/sub 0.8/Ge/sub 0.2/ layer improved drive current by 10% with a 20% reduction in gate leakage current compared with Si-control, while suppressing threshold-voltage rolloff characteristic degradation, and demonstrated excellent I/sub on/--I/sub off/ characteristics of I/sub on/ = 1 mA//spl mu/m for I/sub off/ = 100 nA//spl mu/m. These results are the best in ever reported NMOS with a compressively strained SiGe structure and indicate that a Si-SiGe heterostructure low-field-channel NMOS integrated with a compressively strained SiGe channel PMOS is a promising candidate for high-speed CMOS in 65-nm node logic technology.     

Identification of species in Aspergillus section Flavi based on sequencing of the mitochondrial cytochrome b gene.

The partial sequences of the mitochondrial (mt) cytochrome b gene (402 bp) were determined for species of Aspergillus section Flavi. On the basis of identities of DNA sequences, 77 strains were divided into seven DNA types, from D-1 to D-7. The type strains of A. sojae, A. parasiticus, A. flavus and A. oryzae together, A. tamarii, and A. nomius were placed in DNA types D-1. D-2, D-4, D-5 and D-7, respectively. These species could be differentiated from each other. Furthermore, two other DNA types, D-3 and D-6 were found. DNA type D-3 was closely related to A. parasiticus (D-2) and included one strain that deposited as A. flatus var. flavus and produced aflatoxins B and G. DNA types D-6 included one strain named A. flavus and closely related to A. tamarii. The observations of conidial wall texture by SEM (Scanning Electron Microscopy) supported the relationships derived from the cytochrome b gene. The production of aflatoxins was also examined. Using the DNA sequence of cytochrome b gene, several strains were reidentified. The derived amino acids sequences were all the same in the studied strains. The mt cytochrome b gene is useful and reliable in distinguishing and identifying the species in Aspergillus section Flavi.     

Effect of Cooling Rate on Microstructure and Mechanical Properties of Eutectoid Steel Under Cyclic Heat Treatment

A systematic study has been carried out to ascertain the effect of cooling rate on structure and mechanical properties of eutectoid steel subjected to a novel incomplete austenitization-based cyclic heat treatment process up to 4 cycles. Each cycle consists of a short-duration holding (6 min) at 775 °C (above A₁) followed by cooling at different rates (furnace cooling, forced air cooling and ice-brine quenching). Microstructure and properties are found to be strongly dependent on cooling rate. In pearlitic transformation regime, lamellar disintegration completes in 61 h and 48 min for cyclic furnace cooling. This leads to a spheroidized structure possessing a lower hardness and strength than that obtained in as-received annealed condition. On contrary, lamellar disintegration does not occur for cyclic forced air cooling with high air flow rate (78 m³ h^?1). Rather, a novel microstructure consisting of submicroscopic cementite particles in a ‘interweaved pearlite’ matrix is developed after 4 cycles. This provides an enhancement in hardness (395 HV), yield strength (473 MPa) and UTS (830 MPa) along with retention of a reasonable ductility (%Elongation = 19) as compared to as-received annealed condition (hardness = 222 HV, YS = 358 MPa, UTS = 740 MPa, %Elongation = 21).