Mjerenje frekvencijskog odziva slušnog pomagala pomoću složenog audio test signala

This paper describes the implementation of composed audio test signal (CATS) based test system for evaluation of electroacoustic performance of hearing aids. The system applies a frequency-shaped CATS sequence to a hearing aid as an acoustic stimulus and measures the acoustic response of the aid in IEC standard occluded-ear stimulator. The frequency response can then be found by taking the discrete Fourier Transform of the impulse response. This method has several advantages over traditional noise-based methods regard measurements in the absence or presence of the external interference noise.U članku je opisana primjena složenog audio test signala (CATS) pri određivanju elektroakustičkih svojstava slušnih pomagala. Test sustav primjenjuje frekvencijski ugođenu CATS sekvenciju kao akustičku pobudu za mjerenje akustičkog odziva slušnog pomagala u stimulatoru po IEC standardu. Frekvencijski odziv se dobiva iz impulsnog odziva pomoću diskretne Fourierove transformacije. Ta metoda (CATS) ima znatne prednosti spram uobičajene mjerne metode sa šumnim signalom, pri mjerenju u prisutnosti ili odsutnosti vanjskog interferirajućeg šuma

The neural EGF family member CALEB/NGC mediates dendritic tree and spine complexity

The development of dendritic arborizations and spines is essential for neuronal information processing, and abnormal dendritic structures and/or alterations in spine morphology are consistent features of neurons in patients with mental retardation. We identify the neural EGF family member CALEB/NGC as a critical mediator of dendritic tree complexity and spine formation. Overexpression of CALEB/NGC enhances dendritic branching and increases the complexity of dendritic spines and filopodia. Genetic and functional inactivation of CALEB/NGC impairs dendritic arborization and spine formation. Genetic manipulations of individual neurons in an otherwise unaffected microenvironment in the intact mouse cortex by in utero electroporation confirm these results. The EGF-like domain of CALEB/NGC drives both dendritic branching and spine morphogenesis. The phosphatidylinositide 3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) signaling pathway and protein kinase C (PKC) are important for CALEB/NGC-induced stimulation of dendritic branching. In contrast, CALEB/NGC-induced spine morphogenesis is independent of PI3K but depends on PKC. Thus, our findings reveal a novel switch of specificity in signaling leading to neuronal process differentiation in consecutive developmental events