A protocol for sound localization testing with young and aging normal hearing subjects

An important aspect of processing auditory stimulus is the ability to localize the source of a sound within the environment. Localization has been defined as the ability to determine the direction of sound (Tonning, 1975; Cranford, Boose, & Moore, 1990; Middlebrooks & Green, 1991; Cranford Andres, Piatz, & Reissig, 1993; Lorenzi Gatehouse, & Lever, 1999; Abel, Giguere, Consoli, & Papsin, 2000). Previous researchers have used a variety of test stimuli, test environments, loudspeaker arrays, and ages and numbers of subjects to measure the ability to localize sounds. Despite the obvious need for individuals to identify the specific location of a sound source, the variety of approaches suggests that there is no standard process for measuring localization abilities. As there is no gold standard for localization assessment, it is difficult to compare previous studies of localization. Therefore, a standardized protocol for measuring localization abilities would attenuate the need to vary testing procedures while determining an individual\u27s ability to identify sound sources as part of a complete audiological assessment. Forty male and 40 female adults, ages 21 to 60 years with normal hearing sensitivity and normal temporal processing abilities, will be used as subjects in this study. A protocol for localization testing developed by the primary investigator will be used to measure the subjects\u27 localization abilities. All testing will be completed in an IAC sound treated room, using eight sound field speakers. Each speaker will be arranged symmetrically on the wall, positioned within the horizontal plane with 45 degree intervals between each. The Central Institute for the Deaf Everyday Sentences (Alpiner & Schow, 2000; Healy & Montgomery, 2006) will be used as test stimuli. Five test conditions, one quiet and four noisy listening conditions, will be used to identify elicit localization. Of particular interest is the direction at which a subject can localize a speech stimulus accurately in the presence of background noise

Analysis of debris from Spacelab Space Life Sciences-1

Airborne microbiological and particulate contamination generated aboard Spacelab modules is a potential safety hazard. In order to shed light on the characteristics of these contaminants, microbial and chemical/particulate analyses were performed on debris vacuumed from cabin and avionics air filters in the Space Life Sciences-1 (SLS-1) module of the Space Transportation System 40 (STS-40) mission 1 month after landing. The debris was sorted into categories (e.g., metal, nonmetal, hair/fur, synthetic fibers, food particles, insect fragments, etc.). Elemental analysis of particles was done by energy dispersive analysis of x rays (metals) and Fourier transform infrared spectroscopy (nonmetals). Scanning electron micrographs were done of most particles. Microbiological samples were grown on R2A culture medium and identified. Clothing fibers dominated the debris by volume. Other particles, all attributed to the crew, resulted from abrasions and impacts during missions operations (e.g., paint chips, plastic, electronic scraps and clothing fibers). All bacterial species identified are commonly found in the atmosphere or on the human body. Bacillus sp. was the most frequently seen bacterium. One of the bacterial species, Enterobacter agglomerans, could cause illness in crew members with depressed immune systems

Defining Moments

Reflections on the people and events that have forged Furman\u27s identity through the university\u27s 175-year history

New solutions of relativistic wave equations in magnetic fields and longitudinal fields

We demonstrate how one can describe explicitly the present arbitrariness in solutions of relativistic wave equations in external electromagnetic fields of special form. This arbitrariness is connected to the existence of a transformation, which reduces effectively the number of variables in the initial equations. Then we use the corresponding representations to construct new sets of exact solutions, which may have a physical interest. Namely, we present new sets of stationary and nonstationary solutions in magnetic field and in some superpositions of electric and magnetic fields.Comment: 25 pages, LaTex fil

The appearance of "forbidden lines" in spectra

A rough calculation shows that the quadrupole term in the radiation of a forbidden line is usually larger than the dipole produced by an external electric field. This is not true, however, when there is an intermediate state, with which both initial and final states combine, and which lies close to one of them. If the J selection rule is violated, and the Laporte rule is obeyed, the radiation cannot be due to the quadrupole term and must be ascribed to the octopole. Hg 2270 is such a line. An octopole transition will have a Zeeman effect distinctively different from that of a dipole or quadrupole

Methane selective oxidation on metal oxide catalysts at low temperatures with O₂ using an NO/NO₂ oxygen atom shuttle

Methane oxidation using O2 over transition metal oxides often requires severe conditions ( >500 °C) to achieve detectable conversion. In this study, NO was used to transfer oxygen atoms from O2, through the facile gas-phase formation of NO2 at moderate conditions (0.1 MPa and 300–400 °C), to oxidize methane over silica-supported transition metal oxides (VOx, CrOx, MnOx, NbOx, MoOx, and WOx). In situ infrared spectroscopy measurements indicated that the reaction likely proceeded by the formation of surface monodentate nitrate intermediates. These nitrate species were formed by the interaction between adsorbed NO2 and the supported metal oxides. During the reaction, the oxides of vanadium, molybdenum, and tungsten formed formaldehyde and CO2, whereas the oxides of chromium, manganese, and niobium produced only CO2. These results are consistent with the known hydrocarbon oxidation chemistry of the metal oxides. Contact time measurements on VOx/SiO2 indicated that formaldehyde was a primary product and CO2 was the final product; conversely, analogous measurements on MnOx/SiO2 showed that CO2 was the sole product. The formaldehyde production rate on VOx/SiO2, MoOx/SiO2, and WOx/SiO2, based on surface sites measured by high temperature oxygen chemisorption, compared favorably to oxygenate production rates for stronger oxidants (N2O and H2O2) reported in the literature