A two-microphone noise reduction system for cochlear implant users with nearby microphones. Part II: Performance Evaluation

Users of cochlear implants (auditory aids, which stimulate the auditory nerve electrically at the inner ear) often suffer from poor speech understanding in noise. We evaluate a small (intermicrophone distance 7 mm) and computationally inexpensive adaptive noise reduction system suitable for behind-the-ear cochlear implant speech processors. The system is evaluated in simulated and real, anechoic and reverberant environments. Results from simulations show improvements of 3.4 to 9.3 dB in signal to noise ratio for rooms with realistic reverberation and more than 18 dB under anechoic conditions. Speech understanding in noise is measured in 6 adult cochlear implant users in a reverberant room, showing average improvements of 7.9–9.6 dB, when compared to a single omnidirectional microphone or 1.3–5.6 dB, when compared to a simple directional two-microphone device. Subjective evaluation in a cafeteria at lunchtime shows a preference of the cochlear implant users for the evaluated device in terms of speech understanding and sound quality.

Radiocarbon impact in a nearby tree of a light-water VVER type nuclear power plant, Paks, Hungary

Tree-ring series were collected for radiocarbon analyses from the vicinity of Paks nuclear power plant (NPP) and a background area (Dunaföldvár) for a 10-yr period (2000–2009). Samples of holocellulose were prepared from the wood and converted to graphite for accelerator mass spectrometry (AMS) 14C measurement using the MICADAS at ETH Zürich. The 14C concentration data from these tree rings was compared to the background tree rings for each year. The global decreasing trend of atmospheric 14C activity concentration was observed in the annual tree rings both in the background area and in the area of the NPP. As an average of the past 10 yr, the excess 14C emitted by the pressurized-water reactor (PWR) NPP to the atmosphere shows only a slight systematic excess (~6‰) 14C in the annual rings. The highest 14C excess was 13‰ (in 2006); however, years with the same 14C level as the background were quite frequent in the tree-ring series.

A nearby M Star with tree Transitting Supter-Earths Discovered by K2

Small, cool planets represent the typical end-products of planetary formation. Studying the architectures of these systems, measuring planet masses and radii, and observing these planets' atmospheres during transit directly informs theories of planet assembly, migration, and evolution. Here we report the discovery of three small planets orbiting a bright (K-s = 8.6 mag) M0 dwarf using data collected as part of K2, the new ecliptic survey using the repurposed Kepler spacecraft. Stellar spectroscopy and K2 photometry indicate that the system hosts three transiting planets with radii 1.5-2.1 R-circle plus, straddling the transition region between rocky and increasingly volatile-dominated compositions. With orbital periods of 10-45 days the planets receive just 1.5-10x the flux incident on Earth, making these some of the coolest small planets known orbiting a nearby star; planet d is located near the inner edge of the system's habitable zone. The bright, low-mass star makes this system an excellent laboratory to determine the planets' masses via Doppler spectroscopy and to constrain their atmospheric compositions via transit spectroscopy. This discovery demonstrates the ability of K2 and future space-based transit searches to find many fascinating objects of interest.

Trace element profiles of the sea anemone Anemonia viridis living nearby a natural CO2 vent

Ocean acidification (OA) is not an isolated threat, but acts in concert with other impacts on ecosystems and species. Coastal marine invertebrates will have to face the synergistic interactions of OA with other global and local stressors. One local factor, common in coastal environments, is trace element contamination. CO2 vent sites are extensively studied in the context of OA and are often considered analogous to the oceans in the next few decades. The CO2 vent found at Levante Bay (Vulcano, NE Sicily, Italy) also releases high concentrations of trace elements to its surrounding seawater, and is therefore a unique site to examine the effects of long-term exposure of nearby organisms to high pCO2 and trace element enrichment in situ. The sea anemone Anemonia viridis is prevalent next to the Vulcano vent and does not show signs of trace element poisoning/stress. The aim of our study was to compare A. viridis trace element profiles and compartmentalization between high pCO2 and control environments. Rather than examining whole anemone tissue, we analyzed two different body compartments-the pedal disc and the tentacles, and also examined the distribution of trace elements in the tentacles between the animal and the symbiotic algae. We found dramatic changes in trace element tissue concentrations between the high pCO2/high trace element and control sites, with strong accumulation of iron, lead, copper and cobalt, but decreased concentrations of cadmium, zinc and arsenic proximate to the vent. The pedal disc contained substantially more trace elements than the anemone's tentacles, suggesting the pedal disc may serve as a detoxification/storage site for excess trace elements. Within the tentacles, the various trace elements displayed different partitioning patterns between animal tissue and algal symbionts. At both sites iron was found primarily in the algae, whereas cadmium, zinc and arsenic were primarily found in the animal tissue. Our data suggests that A. viridis regulates its internal trace element concentrations by compartmentalization and excretion and that these features contribute to its resilience and potential success at the trace element-rich high pCO2 vent.

Chemical and isotopic compositions of samples from the Haakon Mosby mud volcano and nearby

Authigenic carbonates in the caldera of an Arctic (72°N) submarine mud volcano with active methane-bearing fluid discharge are formed at the bottom surface during anaerobic microbial methane oxidation. The microbial community consists of specific methane-producing bacteria, which act as methanotrophic ones in conditions of excess methane, and sulfate reducers developing on hydrogen, which is an intermediate product of microbial CH4 oxidation. Isotopically light carbon (aver. d13C = -28.9 per mil) of CO2 produced during CH4 oxidation is the main carbonate carbon source. Heavy oxygen isotope ratio (aver. d18O = 5 per mil) in carbonates is inherited from seawater sulfate. Rapid sulfate reduction (up to 12 mg S/dm**3/day) results in total exhausting of sulfate ion in the upper sediment layer (10 cm). Because of this carbonates can only be formed in surface sediments near the water-bottom interface. Salinity as well as CO3/Ca and Mg/Ca ratios correspond to the field of non-magnesian calcium carbonate precipitation. Calcite is the dominant carbonate mineral in the methane seep caldera, where it occurs in the paragenetic association with barite. Radiocarbon age of carbonates is about 10 Ka.

Discovery of a low-mass brown dwarf companion of the young nearby star G196-3.

A substellar-mass object in orbit at about 300 astronomical units from the young low-mass star G 196-3 was detected by direct imaging. Optical and infrared photometry and low- and intermediate-resolution spectroscopy of the faint companion, hereafter referred to as G 196-3B, confirm its cool atmosphere ?15 Jupiter masses. The separation and allow its mass to be estimated at 25?10 between the objects and their mass ratio suggest the fragmentation of a collapsing cloud as the most likely origin for G 196-3B, but alternatively it could have originated from a protoplanetary disc that has been dissipated. Whatever the formation process was, the young age of the primary star (about 100 million years) demonstrates that substellar companions can form on short time scales.

Volume, Surface, Connectivity and Size Distribution of Soil Pore Space in CT Images: Comparison of Samples at Different Depths from Nearby Natural and Tillage Areas

The study of soil structure, i.e., the pores, is of vital importance in different fields of science and technology. Total pore volume (porosity), pore surface, pore connectivity and pore size distribution are some (probably the most important) of the geometric measurements of pore space. The technology of X-ray computed tomography allows us to obtain 3D images of the inside of a soil sample enabling study of the pores without disturbing the samples. In this work we performed a set of geometrical measures, some of them from mathematical morphology, to assess and quantify any possible difference that tillage may have caused on the soil. We compared samples from tilled soil with samples from a soil with natural vegetation taken in a very close area. Our results show that the main differences between these two groups of samples are total surface area and pore connectivity per unit pore volume.

Is redshift-dependent evolution of galaxies a theoretical artifact?

The physical validity of the hypothesis of (redshift-dependent) luminosity evolution in galaxies is tested by statistical analysis of an intensively studied complete high-redshift sample of normal galaxies. The necessity of the evolution hypothesis in the frame of big-bang cosmology is confirmed at a high level of statistical significance; however, this evolution is quantitatively just as predicted by chronometric cosmology, in which there is no such evolution. Since there is no direct observational means to establish the evolution postulated in big-bang studies of higher-redshift galaxies, and the chronometric predictions involve no adjustable parameters (in contrast to the two in big-bang cosmology), the hypothesized evolution appears from the standpoint of conservative scientific methodology as a possible theoretical artifact.

Galaxies and large scale structure at high redshifts

It is now straightforward to assemble large samples of very high redshift (z ∼ 3) field galaxies selected by their pronounced spectral discontinuity at the rest frame Lyman limit of hydrogen (at 912 Å). This makes possible both statistical analyses of the properties of the galaxies and the first direct glimpse of the progression of the growth of their large-scale distribution at such an early epoch. Here I present a summary of the progress made in these areas to date and some preliminary results of and future plans for a targeted redshift survey at z = 2.7–3.4. Also discussed is how the same discovery method may be used to obtain a “census” of star formation in the high redshift Universe, and the current implications for the history of galaxy formation as a function of cosmic epoch.

X-ray emission from clusters and groups of galaxies

Recent major advances in x-ray imaging and spectroscopy of clusters have allowed the determination of their mass and mass profile out to ≈1/2 the virial radius. In rich clusters, most of the baryonic mass is in the gas phase, and the ratio of mass in gas/stars varies by a factor of 2–4. The baryonic fractions vary by a factor of ≈3 from cluster to cluster and almost always exceed 0.09 h50−[3/2] and thus are in fundamental conflict with the assumption of Ω = 1 and the results of big bang nucleosynthesis. The derived Fe abundances are 0.2–0.45 solar, and the abundances of O and Si for low redshift systems are 0.6–1.0 solar. This distribution is consistent with an origin in pure type II supernova. The amount of light and energy produced by these supernovae is very large, indicating their importance in influencing the formation of clusters and galaxies. The lack of evolution of Fe to a redshift of z ≈ 0.4 argues for very early enrichment of the cluster gas. Groups show a wide range of abundances, 0.1–0.5 solar. The results of an x-ray survey indicate that the contribution of groups to the mass density of the universe is likely to be larger than 0.1 h50−2. Many of the very poor groups have large x-ray halos and are filled with small galaxies whose velocity dispersion is a good match to the x-ray temperatures.