Development of contrast sensitivity and temporal-frequency selectivity in primate lateral geniculate nucleus

We studied the development of spatial contrast-sensitivity and temporal-frequency selectivity for neurons in the monkey lateral geniculate nucleus. During postnatal week 1, the spatial properties of P-cells and M-cells are hardly distinguishable, with low contrast-sensitivity, sluggish responses, and poor spatial resolution. The acuity of P-cells improves progressively until at least 8 months, but there is no obvious increase in their maximum contrast-sensitivity with age. The contrast sensitivity of M-cells is already clearly higher than that of P-cells by 2 months, and at 8 months of age this characteristic difference between M- and P-cells approaches the adult pattern. There is a major increase in responsiveness during the first 2 postnatal months, especially for M-cells, the peak firing rate of which rises fivefold, on average, between birth and 2 months. Many P-cells in the neonatal and 2-month-old animals did not give statistically reliable responses to achromatic gratings, even at the highest contrasts: this unresponsiveness of P-cells might result from low gain and/or chromatic opponency. The upper limit of temporal resolution in the neonate is low--about one-third of that in the adult. Among M-cells, the improvement in temporal resolution, like that in contrast sensitivity, is rapid over the first 2 months, followed by a slower change approaching the adult value by 8 months of age. The development of contrast sensitivity, responsiveness and temporal tuning are little affected, if at all, by binocular deprivation of pattern vision from birth for even a prolonged period.     

封装与测试——解决功率电子器件的热问题

纽约州立大学Buffalo分校电子封装实验室正在为美国海军开发新型的功率电子封装，在一些极端苛刻的工作条件下（比如在军舰和战机上）．它们能够解决大电流密度、高温和大的温度梯度所引起的种种问题。这类功率电子封装还有可能很快进入民用产品。     

Surface electronic structure of rare earth metals

Angle-resolved UV photoemission has been used to investigate the electronic structure of the (0001) surfaces of scandium, yttrium, praseodymium and gadolinium. Off-normal emission spectra were recorded with high angular resolution, enabling detailed mapping of the dispersion of valence band features. Yttrium and gadolinium show similar results to published data from Ho(0001), suggesting minimal 4f influence in the lanthanide bandstructures. Differences seen on praseodymium and scandium may be due to 4f derived states and surface states respectively.     

An improved system for the control of dissolved oxygen in freshwater aquaria

A system for the removal and control of dissolved oxygen (DO) from freshwater was designed and constructed with aquarium-type fish studies in mind. Degassed water was obtained using a partial vacuum of -14 psi, and DO regulated at an aquarium scale using electronically controlled aeration with timed partial water renewal. The degassing system was capable of producing water with approximately 1.7 mg L(-1) DO within 10 min of operation, and 0.55 mg L(-1) after 2h. The control system was capable of maintaining DO levels of ca 0.8 mg L(-1) over 48 h in the absence of aeration and further capable of precisely controlling DO levels as low as 1.16+/-0.002 mg L(-1) (mean+/-SEM) with aeration over a 48 h period.     

Principal axes and surface fitting methods for three-dimensional image registration

We evaluated the effect of the image acquisition parameters on the accuracy of the principal axes and surface-fitting techniques for three-dimensional image registration. Using two types of phantom objects, MR brain image and a mathematically defined ellipsoid, we simulated pairs of scans with known acquisition parameters, including longitudinal coverage, magnitude of mis-registration, number of sections and section thickness. Both methods are sensitive to the systematic deformation of contours. The principal axes method is also sensitive to incomplete scan coverage and to the x-axis and y-axis misangulation. Both methods are insensitive to the number of sections, section thickness and the number of points per section. Surface fitting performed well without user supervision. There is no need for routine inclusion of the scaling factors as search parameters. The results confirm the feasibility of three-dimensional multimodality registration of brain scans with accuracy 1-2 mm, with surface fitting being the method of choice.