Cellular composition characterizing postnatal development and maturation of the mouse brain and spinal cord

The process of development, maturation, and regression in the central nervous system (CNS) are genetically programmed and influenced by environment. Hitherto, most research efforts have focused on either the early development of the CNS or the late changes associated with aging, whereas an important period corresponding to adolescence has been overlooked. In this study, we searched for age-dependent changes in the number of cells that compose the CNS (divided into isocortex, hippocampus, olfactory bulb, cerebellum, ‘rest of the brain’, and spinal cord) and the pituitary gland in 4–40-week-old C57BL6 mice, using the isotropic fractionator method in combination with neuronal nuclear protein as a marker for neuronal cells. We found that all CNS structures, except for the isocortex, increased in mass in the period of 4–15 weeks. Over the same period, the absolute number of neurons significantly increased in the olfactory bulb and cerebellum while non-neuronal cell numbers increased in the ‘rest of the brain’ and isocortex. Along with the gain in body length and weight, the pituitary gland also increased in mass and cell number, the latter correlating well with changes of the brain and spinal cord mass. The majority of the age-dependent alterations (e.g., somatic parameters, relative brain mass, number of pituitary cells, and cellular composition of the cerebellum, isocortex, rest of the brain, and spinal cord) occur rapidly between the 4th and 11th postnatal weeks. This period includes murine adolescence, underscoring the significance of this stage in the postnatal development of the mouse CNS

The Confidence Database

Understanding how people rate their confidence is critical for the characterization of a wide range of perceptual, memory, motor and cognitive processes. To enable the continued exploration of these processes, we created a large database of confidence studies spanning a broad set of paradigms, participant populations and fields of study. The data from each study are structured in a common, easy-to-use format that can be easily imported and analysed using multiple software packages. Each dataset is accompanied by an explanation regarding the nature of the collected data. At the time of publication, the Confidence Database (which is available at https://osf.io/s46pr/) contained 145 datasets with data from more than 8,700 participants and almost 4 million trials. The database will remain open for new submissions indefinitely and is expected to continue to grow. Here we show the usefulness of this large collection of datasets in four different analyses that provide precise estimations of several foundational confidence-related effects

Modeling and Calibration for Crack Detection in Circular Shafts Supported on Bearings Using Lateral and Torsional Vibration Measurements

In this paper the requisite foundational numerical and experimental investigations that are carried out, to model the “uncracked and cracked” shaft and to identify its bending and torsional vibration responses, are reported. The cylindrical shaft used in this experimental study is continuous over two spans (with a cantilever span carrying a propeller) with ball-bearing supports. During modal tests the backward end of shaft (away from the propeller end and connecting it to an electric motor, required for online monitoring) is fixed to one of the test frame supports; later on this backward end will be connected to an electric motor to carry out online modal monitoring for crack identification. In the numerical study, beam elements are used for modeling the bending and torsional vibrations of the rotating shaft. The paper describes in detail the numerical “linear spring” models developed for representing the effects of “ball bearings and the (experimental test) frame supports” on the vibration frequencies. Shaft response parameters are obtained using modal analysis software, LMS Test Lab, for bending vibrations monitored using accelerometers, and three “sets” of shear strain gages fixed at three different shaft locations measure the torsional vibrations. Effects of different crack depths on bending and torsional frequencies and mode shapes are investigated experimentally and numerically, and the results interpreted to give better comprehension of its vibratory behavior

CHARGE PUMPING IN SILICON ON INSULATOR STRUCTURES USING GATED P-I-N DIODES

Nous présentons une extension de la technique de pompage de charge sur des diodes P+IN+ à grille de contrôle, fabriquées sur silicium sur isolant. Cette méthode nous permet d'accéder aux propriétés des interfaces des structures SOS et SIMOX, tout en évitant l'utilisation de transistors MOS à 5 contacts. Les mesures effectuées sur SIMOX en pulsant la grille et/ou le substrat révèlent l'existence d'une forte densité d'états d'interface rapides et de pièges volumiques au voisinage de l'oxyde enterré.The extension of the charge pumping technique to gated P+IN+ diodes fabricated on silicon on insulator is analysed. This method allows us to evaluate the interface properties in SOS and SIMOX structures, without the need for 5-terminal MOS transistors. The experiment, performed on SIMOX films by pulsing both the gate and substrate, reveal the existence of a high density of fast interface states and bulk traps near the buried oxide

Modeling and Calibration for Crack Detection in Circular Shafts Supported on Bearings Using Lateral and Torsional Vibration Measurements

In this paper the requisite foundational numerical and experimental investigations that are carried out, to model the “uncracked and cracked” shaft and to identify its bending and torsional vibration responses, are reported. The cylindrical shaft used in this experimental study is continuous over two spans (with a cantilever span carrying a propeller) with ball-bearing supports. During modal tests the backward end of shaft (away from the propeller end and connecting it to an electric motor, required for online monitoring) is fixed to one of the test frame supports; later on this backward end will be connected to an electric motor to carry out online modal monitoring for crack identification. In the numerical study, beam elements are used for modeling the bending and torsional vibrations of the rotating shaft. The paper describes in detail the numerical “linear spring” models developed for representing the effects of “ball bearings and the (experimental test) frame supports” on the vibration frequencies. Shaft response parameters are obtained using modal analysis software, LMS Test Lab, for bending vibrations monitored using accelerometers, and three “sets” of shear strain gages fixed at three different shaft locations measure the torsional vibrations. Effects of different crack depths on bending and torsional frequencies and mode shapes are investigated experimentally and numerically, and the results interpreted to give better comprehension of its vibratory behavior

HOT ELECTRON RELIABILITY OF DEEP SUBMICRON MOS TRANSISTORS

Nous étudions la dégradation des performances des transistors MOS ultra-courts (0.3 µm - 0.6 µm) engendrée par l'injection de porteurs chauds. Ces dispositifs ont un canal N, une structure conventionnelle (non LDD) et ont été optimisés pour fonctionner à 3 V. Plusieurs types de contraintes out été analysés. Un suivi systématique des paramètres importants a été réalisé en cours de vieillissement, la dégradation étant ensuite évaluée par des méthodes de caractérisation fine. L'influence des tensions d'alimentation sur la durée de vie des dispositifs est étudiée. Ces résultats sont interprétés en tenant compte de l'extension de la zone de défauts et du taux de génération locale d'états d'interface.The hot electron induced degradation of fully optimized N-channel MOSFET's, having channel lengths in the range 0.3 µm - 0.6 µm, is systematically investigated. The created defects and their influence on the device performance are evaluated with very sensitive techniques and explained using 2D modelling. The device lifetime is analysed as a function of the biasing conditions. These results are interpreted by taking into consideration the extension of the defective region as well as the local generation rate of interface states

OMAE2004-51109 CRACK IDENTIFICATION ON A CROSS-STIFFENED PLATE PANEL

ABSTRACT Early identification of cracks in complex structures is desirable for the safety of operation and economy of maintenance of the structure. Monitoring of the vibration response of structures is a well-known technique for crack identification. As the complexity of the structure increases manual inspection becomes difficult and the use of on-line monitoring techniques for crack detection becomes more desirable. This paper discusses the use of a structure's vibration response in the early detection of cracks. Analytical and experimental studies of the effect of cracks on the vibration response of an 1/20 scale aluminum model of the stiffened side shell panel of a tanker were carried out. The model was carefully designed to obtain natural frequencies and mode shapes similar to those of the prototype structure. The results of the analytical study were used to determine the best locations to place the sensors on the experimental model. Results of the experimental and analytical studies are reported