Top-down inputs enhance orientation selectivity in neurons of the primary visual cortex during perceptual learning.

Perceptual learning has been used to probe the mechanisms of cortical plasticity in the adult brain. Feedback projections are ubiquitous in the cortex, but little is known about their role in cortical plasticity. Here we explore the hypothesis that learning visual orientation discrimination involves learning-dependent plasticity of top-down feedback inputs from higher cortical areas, serving a different function from plasticity due to changes in recurrent connections within a cortical area. In a Hodgkin-Huxley-based spiking neural network model of visual cortex, we show that modulation of feedback inputs to V1 from higher cortical areas results in shunting inhibition in V1 neurons, which changes the response properties of V1 neurons. The orientation selectivity of V1 neurons is enhanced without changing orientation preference, preserving the topographic organizations in V1. These results provide new insights to the mechanisms of plasticity in the adult brain, reconciling apparently inconsistent experiments and providing a new hypothesis for a functional role of the feedback connections

Yunus Emre kültür ve sanat haftası

Taha Toros Arşivi, Dosya No: 91/A-Yunus Emr

Atatürk'e hangi yüzle bakmak

Taha Toros Arşivi, Dosya No: 172-Niyazi-Mediha Berkes. Not: Gazetenin “Atatürk'ün Yöntemi ve Yönetimi” köşesinde yayımlanmıştır.İstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

Pat and Mary Zondervan Library, Rice Bell Tower (1986)

https://pillars.taylor.edu/campus-dedications/1028/thumbnail.jp

Synergism in the extraction of Fe(III) and Co(II) with anthranilic acid in the presence of organic bases

1073-1076The extraction of Fe(III) and Co(II) with anthranilic acid in benzene in the presence of nitrogen containing organic bases such as pyridine and β-picoline has been studied. The effect of various parameters affecting extractions has been investigated. The compositions of synergistic adducts extracted into the organic phase have been proposed on the basis of slope analysis method. Based on the extraction data, some separations of metal ions have also been achieved with fairly high separation factors

Parnassus 1991

The 1991 edition of the student literary journal, Parnassus, published by Taylor University in Upland, Indiana

Müsahabe:Ziya Gök Alp neler istiyordu:Türk inkilabı neler yaptı?

Taha Toros Arşivi, Dosya No: 36-Ziya Gökalp. Not: 15 Kanun-ı Sani - 1 Nisan 1933 tarihleri arasında yayımlanan dizi yazısıdır.İstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

Tribological study on tailored-formed axial bearing washers

To enhance tribological contacts under cyclic load, high performance materials are required. Utilizing the same high-strength material for the whole machine element is not resource-efficient. In order to manufacture machine elements with extended functionality and specific properties, a combination of different materials can be used in a single component for a more efficient material utilization. By combining different joining techniques with subsequent forming, multi-material or tailored components can be manufactured. To reduce material costs and energy consumption during the component service life, a less expensive lightweight material should be used for regions remote from the highly stressed zones. The scope is not only to obtain the desired shape and dimensions for the finishing process, but also to improve properties like the bond strength between different materials and the microscopic structure of the material. The multi-material approach can be applied to all components requiring different properties in separate component regions such as shafts, bearings or bushes. The current study exemplarily presents the process route for the production of an axial bearing washer by means of tailored forming technology. The bearing washers were chosen to fit axial roller bearings (type 81212). The manufacturing process starts with the laser wire cladding of a hard facing made of martensitic chromium silicon steel (1.4718) on a base substrate of S235 (1.0038) steel. Subsequently, the bearing washers are forged. After finishing, the surfaces of the bearing washers were tested in thrust bearings on an FE-8 test rig. The operational test of the bearings consists in a run-in phase at 250 rpm. A bearing failure is determined by a condition monitoring system. Before and after this, the bearings were inspected by optical and ultrasonic microscopy in order to examine whether the bond of the coat is resistant against rolling contact fatigue. The feasibility of the approach could be proven by endurance test. The joining zone was able to withstand the rolling contact stresses and the bearing failed due to material-induced fatigue with high cycle stability