Stereoscopic depth movement: two eyes less sensitive than one

Visual sensitivity to stimuli with sinusoidal movement was examined under a number of conditions of binocular stimulation. Sensitivity to stereoscopic movement in depth was reduced in comparison to that for monocular movement. The reduced sensitivity appeared to be due to the presence of stereoscopic depth movement, as opposed to stereoscopic stimulation, binocular movement, or fusion of the images.     

Microanalysis of individual mitochondrial granules with diameters less than 1000 angstroms

A scanning electron microscope was converted to an electron microprobe with high spatial resolution by the addition of a transmitted electron detector and a solid-state x-ray detector. Spectra obtained from mitochondrial granules of chondrocytes in situ confirm the suspected presence of calcium and phosphorus. Contamination during analysis can lead to false indications of silicon in living tissue.     

100以内素数之高精度对数的一个计算方法

本文利用指数丢番图方程的结果给出了 1 0 0以内素数之高精度对数的一个计算方法     

Time and spatial dependence of the concentration of less than 105 microelectrode-generated molecules

The time and spatial dependence of the concentration of as few as 40,000 electrogenerated, redox-active molecules has been determined. The distance between generator and detector microelectrodes in an array used in the study could be varied from 0.8 to 28 micrometers. Measurements of a sufficiently small ensemble of molecules allowed the experimental results to be compared with a quantitative simulation of the random movement of each member of the ensemble. The transit time of an electrogenerated species from the generator to a collector microelectrode was measured as a function of viscosity, diffusivity, and distance.     

Anomalous increase in carbon capacitance at pore sizes less than 1 nanometer

Carbon supercapacitors, which are energy storage devices that use ion adsorption on the surface of highly porous materials to store charge, have numerous advantages over other power-source technologies, but could realize further gains if their electrodes were properly optimized. Studying the effect of the pore size on capacitance could potentially improve performance by maximizing the electrode surface area accessible to electrolyte ions, but until recently, no studies had addressed the lower size limit of accessible pores. Using carbide-derived carbon, we generated pores with average sizes from 0.6 to 2.25 nanometer and studied double-layer capacitance in an organic electrolyte. The results challenge the long-held axiom that pores smaller than the size of solvated electrolyte ions are incapable of contributing to charge storage.     

Closed-shell molecules that ionize more readily than cesium

We report a class of molecules with extremely low ionization enthalpies, one member of which has been determined to have a gas-phase ionization energy (onset, 3.51 electron volts) lower than that of the cesium atom (which has the lowest gas-phase ionization energy of the elements) or of any other known closed-shell molecule or neutral transient species reported. The molecules are dimetal complexes with the general formula M2(hpp)4 (where M is Cr, Mo, or W, and hpp is the anion of 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine), structurally characterized in the solid state, spectroscopically characterized in the gas phase, and modeled with theoretical computations. The low-energy ionization of each molecule corresponds to the removal of an electron from the delta bonding orbital of the quadruple metal-metal bond, and a strong interaction of this orbital with a filled orbital on the hpp ligands largely accounts for the low ionization energies.     

Clinical trials. Enforcers halt NIH study called less risky than outdoor play

How much risk should healthy children face in a research experiment? The answer can land even the best clinicians in hot water, especially if they read the rules differently from the government officials who must enforce them.     

Extreme bendability of DNA less than 100 base pairs long revealed by single-molecule cyclization

The classical view of DNA posits that DNA must be stiff below the persistence length [<150 base pairs (bp)], but recent studies addressing this have yielded contradictory results. We developed a fluorescence-based, protein-free assay for studying the cyclization of single DNA molecules in real time. The assay samples the equilibrium population of a sharply bent, transient species that is entirely suppressed in single-molecule mechanical measurements and is biologically more relevant than the annealed species sampled in the traditional ligase-based assay. The looping rate has a weak length dependence between 67 and 106 bp that cannot be described by the worm-like chain model. Many biologically important protein-DNA interactions that involve looping and bending of DNA below 100 bp likely use this intrinsic bendability of DNA.     

More is less: signal processing and the data deluge

The data deluge is changing the operating environment of many sensing systems from data-poor to data-rich--so data-rich that we are in jeopardy of being overwhelmed. Managing and exploiting the data deluge require a reinvention of sensor system design and signal processing theory. The potential pay-offs are huge, as the resulting sensor systems will enable radically new information technologies and powerful new tools for scientific discovery.