A Functional Role for Neural Columns: Resolving F2 Transition Variability in Stop Place Categorization

Documented examples from neuroethology have revealed species-specific neural encoding mechanisms capable of mapping highly variable, but lawful, visual and auditory inputs within neural columns. By virtue of the entire column being the functional unit of both representation and processing, signal variation is collectively ‘absorbed’, and hence normalized, to help form natural categories possessing an underlying physically-based commonality. Stimulus-specific ‘tolerance ranges’ define the limits of signal variation, effectively shaping the functionality of the columnar-based processing. A conceptualization for an analogous human model utilizing this evolutionarily conserved neural encoding strategy for signal variability absorption is described for the non-invariance issue in stop place perception

Why the Left Hemisphere Is Dominant for Speech Production: Connecting the Dots

Evidence from seemingly disparate areas of speech/language research is reviewed to form a unified theoretical account for why the left hemisphere is specialized for speech production. Research findings from studies investigating hemispheric lateralization of infant babbling, the primacy of the syllable in phonological structure, rhyming performance in split-brain patients, rhyming ability and phonetic categorization in children diagnosed with developmental apraxia of speech, rules governing exchange errors in spoonerisms, organizational principles of neocortical control of learned motor behaviors, and multi-electrode recordings of human neuronal responses to speech sounds are described and common threads highlighted. It is suggested that the emergence, in developmental neurogenesis, of a hard-wired, syllabically-organized, neural substrate representing the phonemic sound elements of one’s language, particularly the vocalic nucleus, is the crucial factor underlying the left hemisphere’s dominance for speech production

“A Shorthand of Stars”: From John to Thomas Pynchon

The June 1888 issue of the Phonographic World magazine presented John Pynchon, an ancestor of Thomas, as “The First American Shorthand Reporter”. While most biographical criticism to date of Thomas Pynchon has focused on the cameo appearance of a thinly veiled William Pynchon in Gravity’s Rainbow, we here set out further historical information on John alongside an appraisal of shorthand in the novels of Thomas

Time-resolved photoelectron imaging of excited state relaxation dynamics in phenol, catechol, resorcinol and hydroquinone

Time-resolved photoelectron imaging was used to investigate the dynamical evolution of the initially prepared S1 (\u3c0\u3c0*) excited state of phenol (hydroxybenzene), catechol (1,2-dihydroxybenzene), resorcinol (1,3-dihydroxybenzene), and hydroquinone (1,4-dihydroxybenzene) following excitation at 267 nm. Our analysis was supported by ab initio calculations at the coupled-cluster and CASSCF levels of theory. In all cases, we observe rapid (<1 ps) intramolecular vibrational redistribution on the S1potential surface. In catechol, the overall S1 state lifetime was observed to be 12.1 ps, which is 1\u20132 orders of magnitude shorter than in the other three molecules studied. This may be attributed to differences in the H atom tunnelling rate under the barrier formed by a conical intersection between the S1 state and the close lying S2 (\u3c0\u3c3*) state, which is dissociative along the O\u2013H stretching coordinate. Further evidence of this S1/S2 interaction is also seen in the time-dependent anisotropy of the photoelectron angular distributions we have observed. Our data analysis was assisted by a matrix inversion method for processing photoelectron images that is significantly faster than most other previously reported approaches and is extremely quick and easy to implement.Peer reviewed: YesNRC publication: Ye

Why the Left Hemisphere Is Dominant for Speech Production: Connecting the Dots

Evidence from seemingly disparate areas of speech/language research is reviewed to form a unified theoretical account for why the left hemisphere is specialized for speech production. Research findings from studies investigating hemispheric lateralization of infant babbling, the primacy of the syllable in phonological structure, rhyming performance in split-brain patients, rhyming ability and phonetic categorization in children diagnosed with developmental apraxia of speech, rules governing exchange errors in spoonerisms, organizational principles of neocortical control of learned motor behaviors, and multi-electrode recordings of human neuronal responses to speech sounds are described and common threads highlighted. It is suggested that the emergence, in developmental neurogenesis, of a hard-wired, syllabically-organized, neural substrate representing the phonemic sound elements of one’s language, particularly the vocalic nucleus, is the crucial factor underlying the left hemisphere’s dominance for speech production

A simple multigrid scheme for solving the Poisson equation with arbitrary domain boundaries

We present a new multigrid scheme for solving the Poisson equation with Dirichlet boundary conditions on a Cartesian grid with irregular domain boundaries. This scheme was developed in the context of the Adaptive Mesh Refinement (AMR) schemes based on a graded-octree data structure. The Poisson equation is solved on a level-by-level basis, using a "one-way interface" scheme in which boundary conditions are interpolated from the previous coarser level solution. Such a scheme is particularly well suited for self-gravitating astrophysical flows requiring an adaptive time stepping strategy. By constructing a multigrid hierarchy covering the active cells of each AMR level, we have designed a memory-efficient algorithm that can benefit fully from the multigrid acceleration. We present a simple method for capturing the boundary conditions across the multigrid hierarchy, based on a second-order accurate reconstruction of the boundaries of the multigrid levels. In case of very complex boundaries, small scale features become smaller than the discretization cell size of coarse multigrid levels and convergence problems arise. We propose a simple solution to address these issues. Using our scheme, the convergence rate usually depends on the grid size for complex grids, but good linear convergence is maintained. The proposed method was successfully implemented on distributed memory architectures in the RAMSES code, for which we present and discuss convergence and accuracy properties as well as timing performances.Comment: 33 pages, 15 figures, accepted for publication in Journal of Computational Physic

Joint consensus statement and guideline on transcatheter aortic valve implantation (TAVI) in South Africa

The South African Heart Association (SA Heart) together with its major special interest groups, SASCI and SCTSSA represent the scientific, educational, socio-economic, ethical and professional interest of cardiac specialists, with a combined membership of over 200 members: We are the only national organisations exclusively representing practicing cardiologists and cardiothoracic surgeons. We are dedicated to maintain the highest standards of practice for our specialists and the highest quality of care for patients who require our care. As a result, we seek to serve as a knowledge resource for patients and funders in matters related to new technology used in our disciplines

Drug, nicotine, and alcohol use among exercisers: does substance addiction co-occur with exercise addiction?

Background: Scholastic works suggest that those at risk for exercise addiction are also often addicted to illicit drugs, nicotine, and/or alcohol, but empirical evidence is lacking. Aims: The aim of the present work was to examine the co-occurrence of illicit drug, nicotine, and alcohol use frequency (prevalence of users) and severity (level of problem in users) among exercisers classified at three levels of risk for exercise addiction: (i) asymptomatic, (ii) symptomatic, and (iii) at-risk. Methods: A sample of 538 regular exercisers were surveyed via the Qualtrics research platform. They completed the (i) Drug Use Disorder Identification Test, (ii) Fagerström Test for Nicotine Dependence, (iii) Alcohol Use Disorder Identification Test, and (iv) Exercise Addition Inventory. Results: A large proportion (n = 59; 10.97%) of the sample was found to be at risk for exercise addiction. The proportion of drug and alcohol users among these participants did not differ from the rest of the sample. However, the incidence of nicotine consumption was lowest among them. The severity of problematic substance use did not differ across the groups. Conclusions: These findings suggest that substance addiction and the risk for exercise addiction are unrelated. In fact, those at risk for exercise addiction exhibited the healthiest profile related to the prevalence of smoking