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For collocated Multiple-Input Multiple-Output (MIMO) radar, we investigate the target detection problem in Gaussian clutter with an unknown but random covariance matrix. An inverse complex Wishart distribution is chosen as prior knowledge for the random covariance matrix. We propose two detectors in the Bayesian framework based on the criteria of the Generalized Likelihood Ratio Test. The two main advantages of the proposed Bayesian detectors are as follows: (1) no training data are required; and (2) a prior knowledge about the clutter is incorporated in the decision rules to achieve detection performance gains. Numerical simulations show that the proposed Bayesian detectors outperform the current commonly used non-Bayesian counterparts, particularly when the sample number of the transmitted waveform is small. In addition, the performance of the proposed detector will decline in parameter mismatched situation.

Objective To investigate the effect of inner mitochondrial membrane peptidase 2-like (IMMP2L) gene mutation on cerebral ischemic injury and its mechanism. Methods The cerebral ischemia/reperfusion (I/R) model was established in wild-type (WT) mice and mice with IMMP2L gene mutation (IMMP2L +/- ) by middle cerebral artery occlusion (MCAO), and cortical tissues were collected at 0, 1, 5 and 24 hours after reperfusion. Laser speckle contrast imaging (LSCI) was used to monitor the change in cerebral blood flow (CBF). Longa behavioral score was used to evaluate neurological function. triphenyltetrazolium chloride (TTC), HE staining was used to evaluate cerebral infarction and neuron injury, TUNEL was used to evaluate the neuronal apoptosis. The protein expression of cleaved caspase-3 and apoptosis-inducing factor (AIF)was analyzed by Western blotting. The changes of cerebral blood flow (CBF) were monitored by laser speckle contrast imaging (LSCI), neurological function was evaluated by longa behavioral score, and cerebral infarction area and neuronal injury were observed by TTC staining and HE staining respectively; the changes of neuronal apoptosis were analyzed by TUNEL, and the protein expressions of cleaved caspase-3 (c-caspase-3) and apoptosis inducing factor (AIF) were detected by Western blotting. Results The neurobehavioral score was significantly higher in the IMMP2L +/- versus WT mice. The volume of the infarcted region, the number of degenerated neurons, and the degree of cerebral edema all increased at 5 and 24 hours after reperfusion. The apoptotic neurons increased at 0, 1, 5 and 24 hours after reperfusion and the protein levels of c-caspase-3 and AIF were up-regulated at 5 and 24 hours after I/R. Conclusion IMMP2L mutation aggravates cerebral ischemic injury by activating the mitochondrial apoptosis pathway.