Cochlear nucleus, inferior colliculus, and medial geniculate responses during the behavioral detection of threshold-level auditory stimuli in the rabbit

Rabbits were conditioned to respond behaviorally to auditory stimuli by pairing a white-noise conditioned stimulus (CS) with a corneal airpuff unconditioned stimulus (US). The conditioned response (CR) was movement of the nictitating membrane (NM). After the subjects were responding at better than the 90% correct level, the intensity of the auditory stimulus was reduced to behavioral threshold using a staircase procedure. Simultaneous measurements of neural unit activity and behavioral NM responses were then made in rabbits performing at behavioral threshold. After the experiment was completed neural unit responses during behavioral detection trials were compared to neural responses made during nondetection trials. Neural unit responses to a constant intensity, white-noise stimulus at behavioral threshold were well defined and essentially identical on behavioral detection and nondetection trials in the ventral cochlear nucleus, the ventrolateral division of the central nucleus of the inferior colliculus, and the ventral division of the medial geniculate body. This suggests that an auditory stimulus can be neuronally "detected" without being behaviorally detected, and that the neural "decision" to respond behaviorally is not made in these nuclei. Responses recorded from the dorsomedial division of the central nucleus of the inferior colliculus, the pericentral nucleus of the inferior colliculus, and less commonly in the medial division of the medial geniculate body were also clearly present and nearly identical during the onset of the auditory stimulus, but were sometimes consistently different for detection and nondetection conditions during the latter part of the auditory stimulus. These brain regions appear to receive both auditory and nonauditory inputs, and show responses which are more highly correlated with detection behavior.     

The Impact of Compaction and Sand Migration on Permeability and Non-Darcy Coefficient from Pore-Scale Simulations

Transport in Porous Media - Compaction and sand migration are important problems in loosely consolidated and unconsolidated high-rate gas reservoirs, and proppants in the hydraulic fractures. Their...     

One-Pot Synthesis of Chiral N-Arylamines by Combining Biocatalytic Aminations with Buchwald–Hartwig N-Arylation

The combination of biocatalysis and chemo-catalysis increasingly offers chemists access to more diverse chemical architectures. Here, we describe the combination of a toolbox of chiral-amine-producing biocatalysts with a Buchwald–Hartwig cross-coupling reaction, affording a variety of α-chiral aniline derivatives. The use of a surfactant allowed reactions to be performed sequentially in the same flask, preventing the palladium catalyst from being inhibited by the high concentrations of ammonia, salts, or buffers present in the aqueous media in most cases. The methodology was further extended by combining with a dual-enzyme biocatalytic hydrogen-borrowing cascade in one pot to allow for the conversion of a racemic alcohol to a chiral aniline.     

High frequency conductivity in the charge density wave semiconductor TaS3

We report the observation of frequency dependent conductivity σ (ω) in the charge density wave (CDW) semiconductor TaS₃. Based on σ (ω) and other evidences, we sugest that three different temperature regions occur in this compound: 1-D fluctuating CDW region above T_MI, a coherent CDW state below T_MI, and a CDW glass state at low temperatures.     

An economic model for investing in sulfur oxide control technology development

The model estimates, subject to restrictions, the functional relationship between national sulfur dioxide discharges and investment in control technology development. Estimates may be made for different product demands, allowed cost increases, and clean fuel availabilities. Control technology development may be accelerated by increased investment. Both optimal and sub-optimal solutions are calculated for an example problem. A general computing method is provided.The model was presented at the Industrial Process Design for Pollution Control Workshop, Chicago, Illinois, Oct. 1973; copyright released by the American Institute of Chemical Engineers for publication for the first time in the monographNormative Analysis in Policy Decisions: Public and Private.     

A combined 14N/27Al nuclear magnetic resonance and powder X-ray diffraction study of impurity phases in beta-sialon ceramics

Beta-sialons are ceramic phases occurring in the SiO(2)-Si(3)N(4)-AlN-Al(2)O(3) system. A series of samples with differing compositions has been investigated by magic-angle spinning nuclear magnetic resonance (NMR) spectroscopy and powder X-ray diffraction (XRD). Although the constituent nitrogen nuclei occupy positions of low symmetry in the beta-sialon structure, 14N NMR spectra could be recorded for the samples examined. The origin of the 14N signal could be traced to the presence of an aluminium nitride (AlN) impurity phase with the help of 27Al NMR and XRD results. Similarly, the existence of Al(2)O(3) grains could be readily detected for a number of samples. Thus, the combination of 14N and 27Al NMR is shown to be an especially effective tool in identifying and characterizing impurity phases in sialon ceramics, complementing the results obtained from standard XRD analysis.     

On involutions with middle-dimensional fixed-point locus and holomorphic-symplectic manifolds

Let $g$ be an involution of a compact closed manifold $X$ such that the fixed-point set $X^{g}$ is middle dimensional. Under the assumption that the normal bundle of the fixed-point set is either the tangent or co-tangent bundle conditions on the equivariant invariants of $X$ arise. In particular if $X$ is a holomorphic-symplectic manifold and $g$ an anti holomorphic-symplectic involution one arrives at a generalisation of Beauville’s result that for $X$ a hyper-Kähler manifold the $\hat{A}$ genus of $X^{g}$ is one.     

Synthesis of 5-aminothiazoles as building blocks for library synthesis

A convenient route to 4-phenyl-5-aminothiazoles is described, which offers control over substitution at the 2-position. 2-N-Acylglycinamides were dithionated and a subsequent TFAA-mediated cyclisation step was followed by removal of the 5-N-trifluoroacetyl group providing the free amines. Though applicable generally the method was found to be most effective when introducing aromatic substituents at the 2-position, whereupon moderate overall yields of the 5-amino compounds were obtained.     

What exactly is uncertainty?

Uncertainty is defined in VIM3 as a ‘parameter’ but that, in my view, is a mistake that detracts from the clarity of the concept. Trying to overcome the resulting difficulties while retaining ‘parameter’ has brought about progressive amendments to the definition, and an increasing list of footnotes that have failed to resolve the issue. Surely the uncertainty of a result is the density function (or mass function) that best describes the probability of possible values of the measurand.