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This paper introduces a directionally oriented 2-D filter bank with the property that the individual channels may be critically sampled without loss of information. The passband regions of the component filters are wedge shaped and thus provide directional information. It is shown that these filter bank outputs may be maximally decimated to achieve a(More)
In recent years, tree-structured analysis/reconstruction systems have been extensively studied for use in subband coders for speech. In such systems, it is imperative that the individual channel signals be decimated in such a way that the number of samples coded and transmitted do not exceed the number of samples in the original speech signal. Under this(More)
Ovarian steroids appear to alter neuronal function in women, but direct physiological evidence is lacking. In animals, estradiol enhances excitatory neurotransmission. Progesterone-derived neurosteroids increase GABAergic inhibition. The effect of weak transcranial magnetic stimulation of the motor cortex on the motor evoked potential (MEP) from(More)
OBJECTIVE To determine whether there are menstrual cycle-related effects on cortical excitability in normal women. BACKGROUND Ovarian steroid hormones affect neurotransmission in the brain. Data from animal experiments have shown that progesterone metabolites enhance the action of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the(More)
CONTEXT Alternative and over-the-counter medicines have become increasingly popular choices for many patients who prefer not to take traditional antidepressants. The adrenal androgen and neurosteroid dehydroepiandrosterone (DHEA) is available as over-the-counter hormonal therapy and previously has been reported to have antidepressant-like effects. (More)