Role of soil health in maintaining environmental sustainability of surface coal mining

Mountaintop coal mining (MCM) in the Southern Appalachian forest region greatly impacts both soil and aquatic ecosystems. Policy and practice currently in place emphasize water quality and soil stability but do not consider upland soil health. Here we report soil organic carbon (SOC) measurements and other soil quality indicators for reclaimed soils in the Southern Appalachian forest region to quantify the health of the soil ecosystem. The SOC sequestration rate of the MCM soils was 1.3 MgC ha(-1) yr(-1) and stocks ranged from 1.3 ± 0.9 to 20.9 ± 5.9 Mg ha(-1) and contained only 11% of the SOC of surrounding forest soils. Comparable reclaimed mining soils reported in the literature that are supportive of soil ecosystem health had SOC stocks 2.5-5 times greater than the MCM soils and sequestration rates were also 1.6-3 times greater. The high compaction associated with reclamation in this region greatly reduces both the vegetative rooting depth and infiltration of the soil and increases surface runoff, thus bypassing the ability of soil to naturally filter groundwater. In the context of environmental sustainability of MCM, it is proposed that the entire watershed ecosystem be assessed and that a revision of current policy be conducted to reflect the health of both water and soil.     

Prediction of breakpoint distance in microcellular environments

Experimental studies of path loss distance dependency in line-of-sight microcellular propagation almost always show a dual-slope behaviour. However, there is disagreement in the literature over the best way to predict the breakpoint distance that delineates the change in path loss distance dependency. A new breakpoint equation is presented, the predictions of which are in excellent agreement with breakpoint distances observed in various propagation studies     

Lack of biological effects of water accommodated fractions of chemically- and physically-dispersed oil on molecular, physiological, and behavioral traits of juvenile snapping turtles following embryonic exposure

Snapping turtle (Chelydra serpentina) eggs were exposed to two concentrations of chemically- or physically-dispersed water accommodated fractions of weathered Arabian light crude oil (Low = 0.5 and High = 10 g oil/L water). Solutions were passed through nest substrate to simulate alterations in composition during percolation to egg depth. Hatchlings were raised for 13 months during which numerous endpoints were measured. Prior to percolation, total PAH (“tPAH”; the sum of 52 PAHs measured) in physically-dispersed oil fractions were similar (High, 43; Low 67 mg/L). Following percolation, tPAH was also similar in physically-dispersed fractions (High, 14; Low 24 mg/L). Addition of dispersant increased tPAH prior to percolation in the High treatment (302 mg/L) relative to Low (13 mg/L), but percolation resulted in nearly equal concentrations in both treatments (High, 30; Low, 22 mg/L) due to physical trapping of dispersed oil by the nest substrate. In both chemically- and physically-dispersed fractions, percolation reduced low molecular weight (MW) compounds such that embryos were exposed to primarily mid- to high MW compounds. Total PAH in eggs differed 15-fold between the chemically-dispersed High and physically-dispersed High treatments (560 and 36 µg/kg respectively), the former characterized by higher MW compounds than the latter. While eggs accumulated up to 560 µg/kg tPAH, we observed no effects on hatching success or hatchling/juvenile traits (DNA integrity, survival, growth, metabolism, energy storage, or behavior), our results demonstrate that PAH profiles are altered during percolation, suggesting that experiments with subsurface organisms should be designed to account for compositional changes that occur as the solutions percolate through the substrate.     

Experimental investigation of contact behaviour in grinding

The nature of the wheel and workpiece contact in grinding has a strong effect on the temperature, force and surface integrity as well as wheel wear in grinding. An applied power source method was used to measure the real contact length. The interpretation of contact length measurements is discussed. Experimental measurements of contact length in grinding show that the contact length is much larger than the geometrical contact length. This difference is most significant in fine grinding and in the sparkout stage of plunge grinding. The difference also increases when the table speed is increased. The contact length in wet grinding is longer than the contact length in dry grinding. The contact length when grinding cast iron is shorter than the contact length when grinding mild steel. It is found that grinding geometry, grinding force and the roughness of the grinding wheel have independent effects on the contact length. The newly developed contact length model by the authors describes these effects quantitatively. These results also show the importance of the roughness factor, R_r, for analysis of the contact behaviour in grinding processes.     

Theory development should begin (but not end) with good empirical fits: A comment on Roberts and Pashler (2000).

S. Roberts and H. Pashler (2000) argued against using goodness of fit as evidence to support theories. The authors agree with their suggestions for how to go beyond good fits but disagree with their starting point. In this comment, the authors argue that good fits are part and parcel of theory development, that they are part and parcel of the processes suggested by S. Roberts and H. Pashler, and that they must be the starting point (though far from the ending point) in theoretical development. The authors discuss historical examples of scientific theory development, recent examples of psychological theory development, and development of a particular theory (social contagion theory; J. L. Rodgers & D. C. Rowe, 1993) that S. Roberts and H. Pashler criticized. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integratable wide-band dual polarized antennas with rear field cancellation

Two variations of an integratable coplanar waveguide fed aperture stacked patch antenna are presented, which are capable of generating wideband dual polarized radiation. One of the antennas displays the desired characteristics for reducing polarization loss between an antenna remote unit (ARU) and mobile units at arbitrary angles. The other has a dual input structure and low cross-polarization useful for polarization diversity applications, or it can also produce circular polarization with the addition of a 90/spl deg/ hybrid. Back radiation concerns are addressed with the use of reflector patch elements. Results indicate that the rear directed radiation of the two slot coupled printed antennas mounted on small ground planes can be reduced across a wide bandwidth with the addition of a reflector element.     

CVT-313, a specific and potent inhibitor of CDK2 that prevents neointimal proliferation

The activity of cyclin-dependent kinase 2 (CDK2) is essential for progression of cells from G1 to the S phase of the mammalian cell cycle. CVT-313 is a potent CDK2 inhibitor, which was identified from a purine analog library with an IC50 of 0.5 microM in vitro. Inhibition was competitive with respect to ATP (Ki = 95 nM), and selective CVT-313 had no effect on other, nonrelated ATP-dependent serine/threonine kinases. When added to CDK1 or CDK4, a 8.5- and 430-fold higher concentration of CVT-313 was required for half-maximal inhibition of the enzyme activity. In cells exposed to CVT-313, hyperphosphorylation of the retinoblastoma gene product was inhibited, and progression through the cell cycle was arrested at the G1/S boundary. The growth of mouse, rat, and human cells in culture was also inhibited by CVT-313 with the IC50 for growth arrest ranging from 1.25 to 20 microM. To evaluate the effects of CVT-313 in vivo, we tested this agent in a rat carotid artery model of restenosis. A brief intraluminal exposure of CVT-313 to a denuded rat carotid artery resulted in more than 80% inhibition of neointima formation. These observations suggest that CVT-313 is a promising candidate for evaluation in other disease models related to aberrant cell proliferation.     

Use of C-SAM acoustical microscopy in package evaluations and failure analysis

Acoustical microscopy is gaining wide acceptance in the microelectronic packaging community. C-mode scanning acoustical microscopy, C-SAM, is widely used in package evaluations and for failure analysis. This paper discusses several specific topics. These include: (1) popcorn cracking in SMDs; (2) an evaluation of solder die attach in power packages; (3) an instance of top of die delamination which resulted in electrical failures; and (4) moisture sensitivity of other surface mount power packages and how it resulted in ball bond degradation during a new product qualification.