Mechanical Properties of Simply Supported Prestressed Concrete Beams under Repeated Over-Loadings

Results of an experimental investigation on the mechanical behavior of simply supported prestressed concrete beams under repeated over-loading are described. This load was characterized by higher maximum load near the failure and the relatively slow loading velocity counting at most 100 cycles to the failure. Differences between the dynamic properties of grouted beams and of non-grouted beams under these loadings are also discussed. Test results give many interesting suggestions for the theoretical approach on the load-deformation relation of prestressed concrete baems subject to repeated over-loadings. It must be noticed that the deformation-dependent change of dissipated energy for the prestressed concrete beam is quite different from that for steel structure and of U-shaped curves

ラット大脳皮質における電位オシレーターを駆動するための状況に応じた戦略

Information integration in the brain requires functional connectivity between local neural networks. Here, we investigated the interregional coupling mechanism from the viewpoint of oscillations using optical recording methods. Low-frequency electrical stimulation of rat neocortical slices in a caffeine-containing medium induced oscillatory activity between the primary visual cortex (Oc1) and medial secondary visual cortex (Oc2M), in which the oscillation generator was located in the Oc2M and was triggered by a feedforward signal. During to-and-fro oscillatory activity, neural excitation was marked in layer II/III. When the upper layer was disrupted between Oc1 and Oc2M, feedforward signals could propagate through the deep layer and switch on the oscillator in the Oc2M. When the lower layer was disrupted between Oc1 and Oc2M, feedforward signals could propagate through the upper layer and switch on the oscillator in the Oc2M. In the backward direction, neither the upper layer cut nor the lower layer cut disrupted the propagation of the oscillations. In all cases, the horizontal and vertical pathways were used as needed. Fluctuations in the oscillatory waveforms of the local field potential at the upper and lower layers in the Oc2M were reversed, suggesting that the oscillation originated between the two layers. Thus, the neocortex may work as a safety device for interregional communications in an alternative way to drive voltage oscillators in the neocortex

Brain Activity Stimulated by Prism Adaptation Tasks Utilized for the Treatment of Unilateral Spatial Neglect: A Study with fNIRS

We investigated the neurological basis for efficacy of prism adaptation therapy, which is used for the treatment of poststroke unilateral spatial neglect (USN). Study subjects were 6 USN-positive (+), 6 USN-negative patients, and 6 healthy volunteer control subjects. USN was identified by the Behavioural Inattention Test (BIT). During the tasks, brain activity was assessed with fNIRS via changes in oxyHb concentration per unit length. There was no significant difference in the number of errors in the task between the 3 groups. However, in the USN(+) group there was a significantly greater reduction in oxyHb levels in the right parietal association cortex during the prism adaptation task than in the other 2 groups (P < 0.05). There was an immediate improvement in USN symptoms as well as a significant increase in oxyHb levels during the prism adaptation in the channels covering the right frontal and parietal lobes in 2 patients in the USN(+) group (P < 0.05). This result suggested that decreased activity in the right parietal association cortex, which is related to spatial perception, during the prism adaptation task and task-induced reorganization of the right frontal and parietal areas were involved in improvement in USN symptoms

The utilization of YAP Scintillation Detector for Soft Gamma Radiation Measurement in Backscatter Thickness Gauge

ABSTRACT Interesting properties of a YAP(Ce) scintillator make it an alternative solution for low energy gamma measurement in high counting rates that previously employed GM counter tubes and/or Nal(Tl) scintillators. Some characteristics of the YAP(Ce) crystal combined with a photomultiplier tube have been successfully demonstrated in a backscatter mode of thickness gauging with 241Am gamma-source.

Intermediate-Mass-Elements in Young Supernova Remnants Reveal Neutron Star Kicks by Asymmetric Explosions

The birth properties of neutron stars yield important information on the still debated physical processes that trigger the explosion and on intrinsic neutron-star physics. These properties include the high space velocities of young neutron stars with average values of several 100 km/s, whose underlying "kick" mechanism is not finally clarified. There are two competing possibilities that could accelerate NSs during their birth: anisotropic ejection of either stellar debris or neutrinos. We here present new evidence from X-ray measurements that chemical elements between silicon and calcium in six young gaseous supernova remnants are preferentially expelled opposite to the direction of neutron star motion. There is no correlation between the kick velocities and magnetic field strengths of these neutron stars. Our results support a hydrodynamic origin of neutron-star kicks connected to asymmetric explosive mass ejection, and they conflict with neutron-star acceleration scenarios that invoke anisotropic neutrino emission caused by particle and nuclear physics in combination with very strong neutron-star magnetic fields.Comment: 24 pages, 12 figures, accepted for publication in The Astrophysical Journa

Investigation of Electromagnetic Noise Transmission Characteristics from AC Mains Port to Telecommunication Port

A method of evaluating the isolation factor from an AC mains port to a telecommunication port was investigated. Telecommunication equipment was represented by a 4-port network consisting of a pair of wire and ground. The relationship between input and output signals of the network was represented by an F-matrix and the isolation factor (ratio of input to output signals) was derived from the matrix. We developed a method of measuring the parameters and the measured values for a resistance-network agree well with calculated ones. The evaluation results of the isolation factor for three types of telecommunication equipment show that isolation for differential-mode noise from AC mains to telecommunication ports is larger than that for common-mode noise.2003 IEEE Symposium on Electromagnetic Compatibility, August 18-22, 2003, Bosto

Detection of the reaction intermediates catalyzed by a copper amine oxidase

Consecutive temporal analyses of enzyme structure have been performed during reactions in order to clarify the structure-based reaction mechanism. Four intermediate structures have been determined