An Infrasonic Missing Fundamental Rises at 18.5Hz

The Missing Fundamental (MF) phenomenon is an auditory processing artifact which arises from the perception of a harmonically-structured complex sound in the absence of the complex sound’s fundamental frequency (f0). Constructive interference occurring between constituent waveforms of the harmonic series may elicit a perceptible tone at the f0’s pitch. A related illusion, known as binaural auditory beats (BAB), may also generate nonexistent perceptible pitches through a shared mechanism. A harmonic series suggesting to an infrasonic f0 (1/f) noise and broken MF conditions. This data suggests that an infrasonic MF tone is generated, despite the normally imperceptible nature of the sound. The computational phenomenon reported here may also occur throughout the cortex, where it could influence or induce different conscious states. The practical implications of altering cortical activity is relevant in understanding processing disorders such as Attention Deficit Hyperactivity Disorder and Schizophrenia

Northern Monterey Bay upwelling shadow front : observations of a coastally and surface-trapped buoyant plume

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): C12013, doi:10.1029/2009JC005623.During the upwelling season in central California, northwesterly winds along the coast produce a strong upwelling jet that originates at Point Año Nuevo and flows southward across the mouth of Monterey Bay. A convergent front with a mean temperature change of 3.77 ± 0.29°C develops between the warm interior waters and the cold offshore upwelling jet. To examine the forcing mechanisms driving the location and movement of the upwelling shadow front and its effects on biological communities in northern Monterey Bay, oceanographic conditions were monitored using cross-shelf mooring arrays, drifters, and hydrographic surveys along a 20 km stretch of coast extending northwestward from Santa Cruz, California, during the upwelling season of 2007 (May–September). The alongshore location of the upwelling shadow front at the northern edge of the bay was driven by: regional wind forcing, through an alongshore pressure gradient; buoyancy forces due to the temperature change across the front; and local wind forcing (the diurnal sea breeze). The upwelling shadow front behaved as a surface-trapped buoyant current, which is superimposed on a poleward barotropic current, moving up and down the coast up to several kilometers each day. We surmise that the front is advected poleward by a preexisting northward barotropic current of 0.10 m s−1 that arises due to an alongshore pressure gradient caused by focused upwelling at Point Año Nuevo. The frontal circulation (onshore surface currents) breaks the typical two-dimensional wind-driven, cross-shelf circulation (offshore surface currents) and introduces another way for water, and the material it contains (e.g., pollutants, larvae), to go across the shelf toward shore.Funded primarily by the Gordon and Betty Moore Foundation and the David and Lucile Packard Foundation

Picturing the nation : The Celtic periphery as discursive other in the archaeological displays of the museum of Scotland

Using the archaeological displays at the Museum of Scotland in Edinburgh, this paper examines the exhibition as a site of identity creation through the negotiations between categories of same and Other. Through an analysis of the poetics of display, the paper argues that the exhibition constructs a particular relationship between the Celtic Fringe and Scottish National identity that draws upon the historical discourses of the Highlands and Islands of Scotland as a place and a time \u27apart\u27. This will be shown to have implications for the display of archaeological material in museums but also for contemporary understandings of Scottish National identity. <br /

Genetic Structure Among 50 Species of the Northeastern Pacific Rocky Intertidal Community

Comparing many species' population genetic patterns across the same seascape can identify species with different levels of structure, and suggest hypotheses about the processes that cause such variation for species in the same ecosystem. This comparative approach helps focus on geographic barriers and selective or demographic processes that define genetic connectivity on an ecosystem scale, the understanding of which is particularly important for large-scale management efforts. Moreover, a multispecies dataset has great statistical advantages over single-species studies, lending explanatory power in an effort to uncover the mechanisms driving population structure. Here, we analyze a 50-species dataset of Pacific nearshore invertebrates with the aim of discovering the most influential structuring factors along the Pacific coast of North America. We collected cytochrome c oxidase I (COI) mtDNA data from populations of 34 species of marine invertebrates sampled coarsely at four coastal locations in California, Oregon, and Alaska, and added published data from 16 additional species. All nine species with non-pelagic development have strong genetic structure. For the 41 species with pelagic development, 13 show significant genetic differentiation, nine of which show striking FST levels of 0.1–0.6. Finer scale geographic investigations show unexpected regional patterns of genetic change near Cape Mendocino in northern California for five of the six species tested. The region between Oregon and Alaska is a second focus of intraspecific genetic change, showing differentiation in half the species tested. Across regions, strong genetic subdivision occurs more often than expected in mid-to-high intertidal species, a result that may reflect reduced gene flow due to natural selection along coastal environmental gradients. Finally, the results highlight the importance of making primary research accessible to policymakers, as unexpected barriers to marine dispersal break the coast into separate demographic zones that may require their own management plans

A c-di-GMP Effector System Controls Cell Adhesion by Inside-Out Signaling and Surface Protein Cleavage

In Pseudomonas fluorescens Pf0-1 the availability of inorganic phosphate (Pi) is an environmental signal that controls biofilm formation through a cyclic dimeric GMP (c-di-GMP) signaling pathway. In low Pi conditions, a c-di-GMP phosphodiesterase (PDE) RapA is expressed, depleting cellular c-di-GMP and causing the loss of a critical outer-membrane adhesin LapA from the cell surface. This response involves an inner membrane protein LapD, which binds c-di-GMP in the cytoplasm and exerts a periplasmic output promoting LapA maintenance on the cell surface. Here we report how LapD differentially controls maintenance and release of LapA: c-di-GMP binding to LapD promotes interaction with and inhibition of the periplasmic protease LapG, which targets the N-terminus of LapA. We identify conserved amino acids in LapA required for cleavage by LapG. Mutating these residues in chromosomal lapA inhibits LapG activity in vivo, leading to retention of the adhesin on the cell surface. Mutations with defined effects on LapD's ability to control LapA localization in vivo show concomitant effects on c-di-GMP-dependent LapG inhibition in vitro. To establish the physiological importance of the LapD-LapG effector system, we track cell attachment and LapA protein localization during Pi starvation. Under this condition, the LapA adhesin is released from the surface of cells and biofilms detach from the substratum. This response requires c-di-GMP depletion by RapA, signaling through LapD, and proteolytic cleavage of LapA by LapG. These data, in combination with the companion study by Navarro et al. presenting a structural analysis of LapD's signaling mechanism, give a detailed description of a complete c-di-GMP control circuit—from environmental signal to molecular output. They describe a novel paradigm in bacterial signal transduction: regulation of a periplasmic enzyme by an inner membrane signaling protein that binds a cytoplasmic second messenger

The effects of adolescent ADHD medication on adult addiction susceptibility

During adolescence, the dopaminergic areas of the brain undergo continued development. These areas are often considered to be responsible for incentive-motivated and risk-taking behaviors [1]. Amphetamine (AMPH) increases dopamine (DA) in the synapse both by blocking the monoamine transporters and by releasing DA from synaptic stores and the nerve terminal [2]. Prescription AMPH, such as Adderall®, is one of the most common prescription drugs abused by students and it is possible that adolescent abuse of AMPH could lead to increased substance abuse in adulthood [3]. Because of the similarities between AMPH and Methamphetamine (METH), early AMPH abuse could create neurological changes during adolescent development that prime for METH abuse in adulthood [4]. Expanding on the findings of previous studies in this lab, the current study hypothesized that mice exposed to small, clinically relevant doses of AMPH during adolescence will show behavioral cross- sensitization to a sub-acute dose of METH during adulthood, and that males will demonstrate a higher response when compared to females. Such a response would indicate that AMPH abuse during this adolescent developmental window resulted in long lasting, sexually dimorphic neurological change

The effect of methamphetamine and amphetamine on the activity of matrix metalloproteinase-2 and 9 in BV2 microglia cells.

Methamphetamine (METH) and amphetamine (AMPH) are psychostimulants that are indirect agonists resulting in excess dopamine release within the brain leading to drug-induced neurodegeneration. Microglia cells respond to this neural damage and release matrix metalloproteinase (MMPs) that play an important role in tissue remodeling and potentially a breakdown of the blood brain barrier. Since MMP-2 and 9 enzyme activity can be measured by gelatin zymography, we stimulated a microglia cell line, BV2, exposed to different concentrations of lipopolysaccharide (LPS), to determine the maximum activity of MMP-2 and 9 under stimulatory conditions. This will model microglia exposure to a neurodegenerative environment. The concentration of LPS with the most activity will then be used in conjunction with a dilution series of METH and AMPH. The MMP activity levels from those treated cells will be assessed through gelatin zymographic techniques. Due to tissue damage and BBB remodeling that occurs after abusing psychostimulants, we hypothesize that the activity of MMP-2 and 9 will be up regulated when exposed to METH and AMPH in the presence of LPS stimulation. The upregulation of MMP activity may be linked to the neurodegeneration that occurs in the brain due to misuse of psychostimulants