Spatial eye–hand coordination during bimanual reaching is not systematically coded in either LIP or PRR

Significance When we reach for something, we also look at it. If we reach for two objects at once, one with each hand, we look first at one and then the other. It is not known which brain areas underlie this coordination. We studied two parietal areas known to be involved in eye and arm movements. Neither area was sensitive to the order in which the targets were looked at. This implies that coordinated saccades are driven by downstream areas and not by the parietal cortex as is commonly assumed.</jats:p

Phonon engineering through crystal chemistry

Mitigation of the global energy crisis requires tailoring the thermal conductivity of materials. Low thermal conductivity is critical in a broad range of energy conversion technologies, including thermoelectrics and thermal barrier coatings. Here, we review the chemical trends and explore the origins of low thermal conductivity in crystalline materials. A unifying feature in the latest materials is the incorporation of structural complexity to decrease the phonon velocity and increase scattering. With this understanding, strategies for combining these mechanisms can be formulated for designing new materials with exceptionally low thermal conductivity

A Musical Analysis of Donald Byrd\u27s Electric Byrd

A Musical Analysis of Donald Byrd\u27s Electric Byr

Aquatic Ecosystem Response to Storm Water Abatement Measures in the Ravines of the GVSU Allendale Campus: Establishment of Base-line Biological Condition

The ravine tributary streams surrounding Grand Valley State Universities Allendale campus represent unique and understudied ecosystems, worthy of significant restoration efforts and of long-lasting protection. They are variously affected by storm water runoff, representing a spectrum from severely impacted to relatively pristine. Quantitative macroinvertebrate samples taken from six streams in late June 2007, indicated that insect diversity was positively correlated to ammonium (p=0.057), while total abundance was negatively correlated to phosphate and chlorophyll-a concentration (n.s.). In addition, phosphate, nitrate, sulfate and iron concentrations were elevated in streams that experience significant storm-water runoff and these streams also tended to have lower macroinvertebrate abundance, diversity and richness. These elevated nutrients, phosphorus in particular, were rapidly taken up by the benthic algae as evidenced by declining nutrients, and increased algal pigment and organic matter concentration from up to down-stream (n.s.). Biological uptake did not translate into increased macroinvertebrate abundance, likely because of the flashy discharge regime. Combination of non EPT (Ephemeroptera, Plecoptera, and Trichoptera) metrics indicated that the Shire and Junkyard ravines were in better condition than sites at Isengard and Fangorn—patterns which strongly suggest that extent of storm-water runoff has negatively impacted the macroinvertebrate communities. The fish community assessment indicated that blacknose dace (Rhinichthys atratulus), a species known to prefer cold, clean water, was most abundant in the Shire—the most pristine ravine stream sampled. Comparing length/weight data in the sampled streams to state standards indicated that these dace are not as fit as typically found in other water bodies whereas other taxa, namely the white sucker (Catostomus commersonii) and creek chub (Somotillus atromaculatus) are indistinguishable from state fitness standards. We were successful establishing biological base-line conditions prior to the initiation of a campus wide storm-water abatement program and can use these benchmarks to gage the long-term efficacy of restoration using physicochemical, population, community and ecosystem functional attributes measured in these unique ecosystems

SatNOGS Website Project

The SatNOGS Website project aims to create a web interface for the SatNOGS, or Satellite Network Open Ground Stations, project. The intent of the ongoing project is to make the main SatNOGS project more accessible by creating a web-based software system that contains many of the necessary features needed to run a ground station, and do it in a way that is visually appealing and human-friendly, and to also provide an extension to the main client for control and information presentation needs. A large feature that the application will offer is displaying much of the information that the transmitter is receiving, such as where in the sky the satellite that is being observed is at, whether the ground station is currently on the network, whether it is able to receive information, and even more data on the satellite it is looking at, including possibly a picture and the raw data the satellite is transmitting. This work is being done in collaboration with the ECE Department at Valparaiso University, which is working on aspects of the physical and electronic components. This project, in addition to contributing to this international effort, also provides a laboratory for experiencing and learning the technology and processes for large-scale software system construction

Zintl Chemistry for Designing High Efficiency Thermoelectric Materials

Zintl phases and related compounds are promising thermoelectric materials; for instance, high zT has been found in Yb_(14)MnSb_(11), clathrates, and the filled skutterudites. The rich solid-state chemistry of Zintl phases enables numerous possibilities for chemical substitutions and structural modifications that allow the fundamental transport parameters (carrier concentration, mobility, effective mass, and lattice thermal conductivity) to be modified for improved thermoelectric performance. For example, free carrier concentration is determined by the valence imbalance using Zintl chemistry, thereby enabling the rational optimization of zT. The low thermal conductivity values obtained in Zintl thermoelectrics arise from a diverse range of sources, including point defect scattering and the low velocity of optical phonon modes. Despite their complex structures and chemistry, the transport properties of many modern thermoelectrics can be understood using traditional models for heavily doped semiconductors

Transport properties of the layered Zintl compound SrZnSb_2

Transport properties of the layered Zintl compound SrZnSb_2 have been characterized from room temperature to 725 K on polycrystalline samples. SrZnSb_2 samples were found to be p-type with a Hall carrier concentration of 5×10^(20) cm^(−3) at room temperature, and a small Seebeck coefficient and electrical resistivity are observed. A single band model predicts that, even with optimal doping, significant thermoelectric performance will not be achieved in SrZnSb_2. A relatively low lattice thermal conductivity is observed, κ_L~1.2 W m^(−1) K^(−1), at room temperature. The thermal transport of SrZnSb_2 is compared to that of the layered Zintl compounds AZn2Sb_2 (A=Ca,Yb,Sr,Eu), which have smaller unit cells and larger lattice thermal conductivity, κ_L~2 W m^(−1) K^(−1), at 300K. Ultrasonic measurements, in combination with kinetic theory and the estimated κ_L values, suggest that the lower κ_L of SrZnSb_2 is primarily the result of a reduction in the volumetric specific heat of the acoustic phonons due to the increased number of atoms per unit cell. Therefore, this work recommends that unit cell size should be considered when selecting Zintl compounds for potential thermoelectric application

A high temperature apparatus for measurement of the Seebeck coefficient

A high temperature Seebeck coefficient measurement apparatus with various features to minimize typical sources of error is designed and built. Common sources of temperature and voltage measurement error are described and principles to overcome these are proposed. With these guiding principles, a high temperature Seebeck measurement apparatus with a uniaxial 4-point contact geometry is designed to operate from room temperature to over 1200 K. This instrument design is simple to operate, and suitable for bulk samples with a broad range of physical types and shapes