bluuebunny/crossref_metadata_2025 huggingface dataset:
Radial Corrugations of Multi-Walled Carbon Nanotubes Driven by Inter-Wall Nonbonding Interactions
Authors: Huang Xu , Liang Wentao , Zhang Sulin
Published: September 2010

We perform large-scale quasi-continuum simulations to determine the stable cross-sectional configurations of free-standing multi-walled carbon nanotubes (MWCNTs). We show that at an inter-wall spacing larger than the equilibrium distance set by the inter-wall van der Waals (vdW) interactions, the initial circular cross-sections of the MWCNTs are transformed into symmetric polygonal shapes or asymmetric water-drop-like shapes. Our simulations also show that removing several innermost walls causes even more drastic cross-sectional polygonization of the MWCNTs. The predicted cross-sectional configurations agree with prior experimental observations. We attribute the radial corrugations to the compressive stresses induced by the excessive inter-wall vdW energy release of the MWCNTs. The stable cross-sectional configurations provide fundamental guidance to the design of single MWCNT-based devices and shed lights on the mechanical control of electrical properties.
The Microscopic Origin of Residual Stress for Flat Self-Actuating Piezoelectric Cantilevers
Authors: Lee Jeong Hoon , Hwang Kyo Seon , Kim Tae Song
Published: September 2010

In this study, flat piezoelectric microcantilevers were fabricated under low-stress Pb(Zr0.52Ti0.48)O3 (PZT) film conditions. They were analyzed using the Raman spectrum and wafer curvature methods. Based on the residual stress analysis, we found that a thickness of 1 μm was critical, since stress relaxation starts to occur at greater thicknesses, due to surface roughening. The (111) preferred orientation started to decrease when the film thickness was greater than 1 μm. The d33 value was closely related to the stress relaxation associated with the preferred orientation changes. We examined the harmonic response at different PZT cantilever lengths and obtained a 9.4-μm tip displacement at 3 Vp-p at 1 kHz. These analyses can provide a platform for the reliable operation of piezoelectric microdevices, potentially nanodevice when one needs to have simultaneous control of the residual stress and the piezoelectric properties.
Physical and Chemical Processes to Enhance Oil Recovery from Condensed Corn Distillers Solubles
Authors: Majoni Sandra , Wang Tong , Johnson Lawrence A.
Published: September 2010

Oil recovery from corn fermentation co‐products can provide feedstock for biodiesel production. The effects of physical and chemical processes on oil recovery from condensed corn distillers solubles (CCDS) were investigated. Heating disrupted physical interactions in the CCDS and increased oil recovery by 2.5‐fold when temperature was increased from 25 to 59 °C. Oil recovery at acidic pH conditions was significantly greater than at alkaline pH. Oil recovery at alkaline pH was increased by heating and addition of the reducing agent, sodium metabisulfite. Oil extraction using polar solvents isopropanol and butanol achieved greater than 80% oil recovery. When oil was co‐extracted with zein using hexane and ethanol as co‐solvents, the greatest total oil recovery was achieved, 89%. Churning CCDS at pH 3.5, 50 °C for 3 h achieved up to 80% oil recovery. This study provides data for designing further effective methods for oil separation from corn ethanol co‐products.
States and the Making of the “Service” Party: The Case of the Postwar Ohio Republican Party
Authors: CONLEY BRIAN M.
Published: September 2010

During the second half of the twentieth century, at a time when most observers thought they were in decline, parties were in fact transformed in the US. At the center of this change, scholars argue, was the development, at the national level, of a more centralized and professionally oriented “service” model of party organization within the Republican Party. What the emphasis on the national level obscures, however, is the important role that state parties played in the development of a service style of party organization prior to the 1960s. Nowhere was this more evident than in Ohio, where the postwar Republican Party, led by Ray Bliss, had a significant impact on the development of this new, more centralized “service” approach to party organization. The Bliss model represented one of the most fully developed examples to date, at any level, of the service party, as demonstrated by its organizational continuity over time, and its influence on the subsequent institutionalization of a similar structure within the Republican Party nationally in the 1960s and 1970s.
“SAMO© as an Escape Clause”: Jean-Michel Basquiat's Engagement with a Commodified American Africanism
Authors: RODRIGUES LAURIE A.
Published: September 2010

Heir to the racist configuration of the American art exchange and the delimiting appraisals of blackness in the American mainstream media, Jean-Michel Basquiat appeared on the late 1970s New York City street art scene – then he called himself “SAMO.” Not long thereafter, Basquiat grew into one of the most influential artists of an international movement that began around 1980, marked by a return to figurative painting. Given its rough, seemingly untrained and extreme, conceptual nature, Basquiat's high-art oeuvre might not look so sophisticated to the uninformed viewer. However, Basquiat's work reveals a powerful poetic and visual gift, “heady enough to confound academics and hip enough to capture the attention span of the hip hop nation,” as Greg Tate has remarked. As noted by Richard Marshall, Basquiat's aesthetic strength actually comes from his striving “to achieve a balance between the visual and intellectual attributes” of his artwork. Like Marshall, Tate, and others, I will connect with Basquiat's unique, self-reflexively experimental visual practices of signifying and examine anew Basquiat's active contribution to his self-alienation, as Hebdige has called it. Basquiat's aesthetic makes of his paintings economies of accumulation, building a productive play of contingency from the mainstream's constructions of race. This aesthetic move speaks to a need for escape from the perceived epistemic necessities of blackness. Through these economies of accumulation we see, as Tate has pointed out, Basquiat's “intellectual obsession” with issues such as ancestry/modernity, personhood/property and originality/origins of knowledge, driven by his tireless need to problematize mainstream media's discourses surrounding race – in other words, a commodified American Africanism.
The harmonisation of longitudinal data: a case study using data from cohort studies in The Netherlands and the United Kingdom
Authors: BATH PETER A. , DEEG DORLY , POPPELAARS JAN
Published: September 2010

This paper presents a case study of the challenges and requirements associated with harmonising data from two independently-conceived datasets from The Netherlands and the United Kingdom: the Longitudinal Aging Study Amsterdam (LASA) and the Nottingham Longitudinal Study of Activity and Ageing (NLSAA). The objectives were to create equivalent samples and variables, and to identify the methodological differences that affect the comparability of the samples. Data are available from the two studies' 1992–93 surveys for respondents born during 1908–20, and the common data set had 1,768 records and enabled the creation of 26 harmonised variables in the following domains: demographic composition and personal finances, physical health, mental health and loneliness, contacts with health services, physical activity, religious attendance and pet ownership. The ways in which the methodological differences between the two studies and their different selective attrition might lead to sample differences were carefully considered. It was concluded that the challenges of conducting cross-national comparative research using independent datasets include differences in sampling, study design, measurement instruments, response rates and selective attrition. To reach conclusions from any comparative study about substantive socio-cultural differences, these challenges must first be identified and addressed.
The contribution of new technology to economic growth: lessons from economic history
Authors: Crafts Nicholas
Published: September 2010

This paper reviews the analysis of technological change by cliometricians. It focuses on lessons about total factor productivity (TFP) from growth accounting and on aspects of social capability that are conducive to the effective assimilation of new technology. Key messages are that when TFP growth is very rapid this typically involves reductions in inefficiency not just technological advance and that even really important new technologies have small initial effects on aggregate productivity. Incentive structures matter greatly for the adoption of new technology, but social capability is not independent of the technological epoch as the information and communications technology (ICT) era has emphasized to Europeans.
A Party for the Mezzogiorno: The Christian Democratic Party, Agrarian Reform and the Government of Italy
Authors: FORLENZA ROSARIO
Published: September 2010

In the 1950s the Christian Democratic party turned its attention to agrarian reform projects and development funding for southern Italy. Its social and economic objectives were the destruction of latifundia, the creation of a class of small landowners, industrial and commercial development and the reduction of territorial inequalities. The ultimate goal, however, was political: to gain loyalty, allegiance and electoral consensus. To manage the economy and direct change, the party had to strengthen the organisation, form a ruling class, lay down territorial roots and widen the scope of its propaganda beyond anti-communism. Elections became the testing ground for the party's new reform strategies.
Development of a grazing-incidence insertion device X-ray beam position monitor at the Advanced Photon Source
Authors: Lee S. H. , Den Hartog P. , Yang B. X. , Decker G.
Published: September 2010

Beam stability is always a concern in synchrotron light source facilities, and accurate and stable X-ray beam position monitors (XBPM) are key elements in obtaining desired user beam stability. Currently, Advanced Photon Source is preparing to upgrade its facility to increase productivity and to provide better beam stability. For better beam stability, a grazing-incidence insertion device X-ray beam position monitor (GRID-XBPM) is proposed for the insertion device beamline front ends instead of the current photoemission-based XBPM. The design and development of the GRID-XBPM are summarized in this paper including the thermal simulation results of the GRID-XBPM. Thermal and stress analyses show that it withstands the 21 kW total beam power and the peak heat flux of 1684 W mm−2 at a grazing incidence angle of 0.80° using a heat transfer coefficient of 0.010 Wmm−2 °C−1.
Calcium isotope ratios in the world's largest rivers: A constraint on the maximum imbalance of oceanic calcium fluxes
Authors: Tipper E. T. , Gaillardet J. , Galy A. , Louvat P. , Bickle M. J. , Capmas F.
Published: September 2010

The oceanic mass balance of calcium (Ca) is defined by a balance between the inputs (rivers and hydrothermal) and outputs (bulk carbonate) of Ca. Large rivers were analyzed for Ca isotope ratios (44Ca/42Ca, expressed as Ca) to investigate the source and cycling of riverine Ca, and to add an isotopic mass balance constraint to the oceanic budget of Ca. The new data account for approximately one‐third of the total Ca supplied to the oceans by rivers. Inter‐sample and seasonal variability was assessed by analyzing more than one sample for many rivers. The range in the Ca of large rivers at high water stand is extremely narrow at 0.27‰. Variations in Ca do not correlate with proxies for carbonate, silicate or evaporite derived Ca, and are more likely related either to inherent variability in the lithological sources of Ca or to process related fractionation. The spread in riverine Ca overlaps with the spread in marine limestone Ca consistent with most riverine Ca coming from the recycling of limestones. The Ca isotope composition of continental runoff has an average Ca value of 0.38 ± 0.04‰, identical to recent (5 M.yr) bulk carbonate ooze (0.33 ± 0.13‰, 2S.D.). Isotopic mass balance constrains that the input and output fluxes of Ca to and from the oceans, are balanced to within 15% over time‐scales similar to the residence time of Ca in the oceans (1 M.yr). A greater imbalance between the fluxes would result in a detectable difference between the Ca value of bulk carbonate and the riverine input at the current level of uncertainty. The input and output fluxes could be imbalanced over much shorter time‐scales (such as glacial‐interglacial cycles), in which case the ocean‐carbonate system will not yet have responded, because of the long residence time of Ca. The maximum current flux imbalance of 15% would be sufficient to account for the total variations in Ca concentration over the Tertiary. Such an interpretation is not unique, but is the simplest interpretation given the similarity between the input and output isotopic compositions, and rules out hypotheses of extreme imbalance in the recent global biogeochemical cycle of Ca.
Tree ring evidence for limited direct CO2 fertilization of forests over the 20th century
Authors: Gedalof Ze'ev , Berg Aaron A.
Published: September 2010

The effect that rising atmospheric CO2 levels will have on forest productivity and water use efficiency remains uncertain, yet it has critical implications for future rates of carbon sequestration and forest distributions. Efforts to understand the effect that rising CO2 will have on forests are largely based on growth chamber studies of seedlings, and the relatively small number of FACE sites. Inferences from these studies are limited by their generally short durations, artificial growing conditions, unnatural step‐increases in CO2 concentrations, and poor replication. Here we analyze the global record of annual radial tree growth, derived from the International Tree ring Data Bank (ITRDB), for evidence of increasing growth rates that cannot be explained by climatic change alone, and for evidence of decreasing sensitivity to drought. We find that approximately 20 percent of sites globally exhibit increasing trends in growth that cannot be attributed to climatic causes, nitrogen deposition, elevation, or latitude, which we attribute to a direct CO2 fertilization effect. No differences were found between species in their likelihood to exhibit growth increases attributable to CO2 fertilization, although Douglas‐fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa), the two most commonly sampled species in the ITRDB, exhibit a CO2 fertilization signal at frequencies very near their upper and lower confidence limits respectively. Overall these results suggest that CO2 fertilization of forests will not counteract emissions or slow warming in any substantial fashion, but do suggest that future forest dynamics may differ from those seen today depending on site conditions and individual species' responses to elevated CO2.
Long‐term carbon loss and recovery following selective logging in Amazon forests
Authors: Huang Maoyi , Asner Gregory P.
Published: September 2010

Amazon deforestation contributes significantly to global carbon (C) emissions. In comparison, the contribution from selective logging to atmospheric CO2 emissions, and its impact on regional C dynamics, is highly uncertain. Using a new geographically based modeling approach in combination with high resolution remote sensing data from 1999 to 2002, we estimate that C emissions were 0.04–0.05 Pg C yr−1 due to selective logging from a ∼2,664,960 km2 region of the Brazilian Amazon. Selective logging was responsible for 15–19% higher carbon emissions than reported from deforestation (clear‐cutting) alone. Our simulations indicated that forest carbon lost via selective logging lasts two to three decades following harvest, and that the original live biomass takes up to a century to recover, if the forests are not subsequently cleared. The two‐ to three‐decade loss of carbon results from the biomass damaged by logging activities, including leaves, wood, and roots, estimated to be 89.1 Tg C yr−1 from 1999 to 2002 over the study region, leaving 70.0 Tg C yr−1 and 7.9 Tg C yr−1 to accumulate as coarse woody debris and soil C, respectively. While avoided deforestation is central to crediting rain forest nations for reduced carbon emissions, the extent and intensity of selective logging are also critical to determining carbon emissions in the context of Reduced Emissions from Deforestation and Forest Degradation (REDD). We show that a combination of automated high‐resolution satellite monitoring and detailed forest C modeling can yield spatially explicit estimates of harvest‐related C losses and subsequent recovery in support of REDD and other international carbon market mechanisms.
Pore pressure evolution in deforming granular material: A general formulation and the infinitely stiff approximation
Authors: Goren L. , Aharonov E. , Sparks D. , Toussaint R.
Published: September 2010

The physics of deformation of fluid‐filled granular media controls many geophysical systems, ranging from shear on geological faults to landslides and soil liquefaction. Its great complexity is rooted in the mechanical coupling between two deforming phases: the solid granular network and the fluid‐filled pore network. Often deformation of the granular network leads to pore fluid pressure (PP) changes. If the PP rises enough, the fluid‐filled granular media may transition from a stress‐supporting grain network to a flowing grain‐fluid slurry, with an accompanying catastrophic loss of shear strength. Despite its great importance, the mechanisms and parameters controlling PP evolution by granular shear are not well understood. A formulation describing the general physics of pore fluid response to granular media deformation is developed and used to study simple scenarios that lead to PP changes. We focus on the infinitely stiff end‐member scenario, where granular deformation is prescribed, and the PP responds to this deformation. This end‐member scenario illustrates the two possible modes of pore fluid pressurization: (1) via rapid fluid flow when fluid drainage is good and (2) via pore volume compaction when drainage is poor. In the former case the rate of deformation controls PP evolution, while in the latter case, fluid compressibility is found to be an important parameter and the amount of pressurization is controlled by the overall compaction. The newly suggested fluid‐induced mechanism (mechanism 1) may help explain observations of liquefaction of initially compact soils and shear zones.
Normalized radar cross section of the sea for backscatter: 2. Modulation by internal waves
Authors: Plant William J. , Keller William C. , Hayes Kenneth , Chatham Gene , Lederer Nicholas
Published: September 2010

We report measurements of microwave surface signatures of internal waves with dual‐polarized, coherent, X band radars mounted on three ships and an airplane. In shipboard measurements in the South China Sea, internal waves generally increased the backscattering cross section near the peaks of the internal waves with little detectable decrease afterward. The peak of the cross‐section signature shifted its location relative to the internal wave crest depending on the maximum strain rate of the internal wave. We show that a similar shift is produced in the modulation of short‐gravity waves by internal waves. We suggest that this modulation of “intermediate‐scale” waves causes small‐scale radar scatterers to maximize at this location. In shipboard measurements off the New Jersey coast, the range resolution of the radar was sufficiently small to allow us to detect significant modulation of gravity waves on the order of 15–30 m long by the internal waves. At the high incidence angles of the shipboard measurements, the cross section for horizontally polarized transmit and receive signals, σo(HH), regularly exceeded that for vertically polarized transmit and receive signals, σo(VV), near the internal wave crest by 5–10 dB. At the more moderate incidence angles observed from the aircraft, maximum values of σo(HH) and σo(VV) are more nearly equal, with σo(HH) often being comparable to σo(VV) and only occasionally exceeding it. These observations suggest that roughness due to breaking short‐gravity waves plays a significant role in producing microwave signatures of internal waves, even at moderate incidence angles where it competes with the modulation of wind‐generated waves. The intensity of modulation of the cross section caused by internal waves observed from the plane depended little on the direction of observation. Internal wave surface signatures from the aircraft became less visible with increasing wind speed, being very difficult to observe at 9 m/s.
Coupling mantle convection and tidal dissipation: Applications to Enceladus and Earth‐like planets
Authors: Běhounková Marie , Tobie Gabriel , Choblet Gaël , Čadek Ondřej
Published: September 2010

Anelastic dissipation of tidal forces likely contributes to the thermal budget of several satellites of giant planets and Earth‐like planets closely orbiting other stars. In order to address how tidal heating influences the thermal evolution of such bodies, we describe here a new numerical tool that solves simultaneously mantle convection and tidal dissipation in a three‐dimensional spherical geometry. Since the two processes occur at different timescales, tidal dissipation averaged over a forcing period is included as a volumetric heat source for mantle dynamics. For the long‐term flow, a purely viscous material is considered, whereas a Maxwell‐like formalism is employed for the tidal viscoelastic problem. Due to the strongly temperature dependent rheological properties of both mechanisms, the coupling is achieved via the temperature field. The model is applied to two examples: Enceladus and an Earth‐like planet. For Enceladus, our new 3‐D method shows that the tidal strain rates are strongly enhanced in hot upwellings when compared with classical methods. Moreover, the heat flux at the base of Enceladus' ice shell is strongly reduced at the poles, thus favoring the preservation of a liquid reservoir at depth. For Earth‐like planets, tidal dissipation patterns are predicted for different orbital configuration. Thermal runaway is observed for orbital periods smaller than a critical value (e.g., 30 days for an eccentricity of 0.2 and 3:2 resonance). This is likely to promote large‐scale melting of the mantle and Io‐like volcanism.
Drought legacies influence the long‐term carbon balance of a freshwater marsh
Authors: Rocha Adrian V. , Goulden Michael L.
Published: September 2010

Experimental manipulations provide a powerful tool for understanding an ecosystem's response to environmental perturbation. We combined paired eddy covariance towers with an experimental manipulation of water availability to determine the response of marsh carbon balance to drought. We monitored the Net Ecosystem Exchange of CO2 (NEE) in two ponds from 2004 to 2009 at the San Joaquin Freshwater Marsh (SJFM), and subjected one of the ponds to a yearlong drought treatment in 2007. The two ponds experienced similar flooding and environmental regimes before and after the drought, ensuring that differences between ponds were largely attributable to the 2007 drought. Drought substantially reduced surface greenness, as measured by the Enhanced Vegetation Index (EVI) and photosynthetic carbon sequestration, primarily by inhibiting leaf area development. Respiratory carbon losses were less influenced by drought than photosynthetic carbon gains. The effect of the drought lasted several years, with delayed leaf area development and peak carbon uptake rates during the subsequent year, and reduced leaf area for a couple of years. The combined effect of the drought and legacy effects created an overall loss of carbon that was equivalent to 4 years of the maximum annual carbon sequestration observed over a decade. Our results indicate that drought can have long‐term impacts on ecosystem carbon balance and that future projected drought increases in Southern California will have a negative impact on marsh carbon sequestration.
Effects of irrigated agroecosystems: 2. Quality of soil water and groundwater in the southern High Plains, Texas
Authors: Scanlon B. R. , Gates J. B. , Reedy R. C. , Jackson W. A. , Bordovsky J. P.
Published: September 2010

Trade‐offs between water‐resource depletion and salinization need to be understood when promoting water‐conservative irrigation practices. This companion paper assesses impacts of groundwater‐fed irrigation on soil water and groundwater quality using data from the southern High Plains (SHP). Unsaturated zone soil samples from 13 boreholes beneath irrigated agroecosystems were analyzed for water‐extractable anions. Salt accumulation in soils varies with irrigation water quality, which ranges from low salinity in the north (median Cl: 21 mg/L) to higher salinity in the south (median Cl: 180 mg/L). Large Cl bulges under irrigated agroecosystems in the south are similar to those under natural ecosystems, but they accumulated over decades rather than millennia typical of natural ecosystems. Profile peak Cl concentrations (1200–6400 mg/L) correspond to irrigation efficiencies of 92–98% with respect to drainage and are attributed to deficit irrigation with minimal flushing. Perchlorate (ClO4) also accumulates under irrigated agroecosystems, primarily from irrigation water, and behaves similarly to Cl. Most NO3‐N accumulation is below the root zone. Groundwater total dissolved solids (TDS) have increased by ≤960 mg/L and NO3‐N by ≤9.4 mg/L since the early 1960s. Mobilization of salts that have accumulated under irrigated agroecosystems is projected to degrade groundwater much more in the future because of the essentially closed‐basin status of the aquifer, with discharge occurring primarily through irrigation pumpage. TDS are projected to increase by an additional 2200 mg/L (median), ClO4 by 21 μg/L, and NO3‐N by 52 mg/L. Water and salt balances should be considered in irrigation management in order to minimize salinization issues.
Nostradamus: The radar that wanted to be a seismometer
Authors: Occhipinti Giovanni , Dorey Philippe , Farges Thomas , Lognonné Philippe
Published: September 2010

Surface waves emitted after large earthquakes are known to induce, by dynamic coupling, atmospheric infrasonic waves propagating upward through the neutral and ionized atmosphere. Those waves have been detected in the past at ionospheric heights using a variety of techniques, such as HF Doppler sounding or GPS receivers. The HF Doppler technique, particularly sensitive to the ionospheric signature of Rayleigh waves is used here to show ionospheric perturbations consistent with the propagation of Rayleigh wave phases R1 and R2 following the Sumatra earthquake on the 28 March 2005 (M = 8.6). This is in our knowledge the first time that the phase R2 is detected by ionospheric sounding. In addition, we prove here that the ionospheric signature of R2 is also observed by over‐the‐horizon (OTH) Radar. The latter was never used before to detect seismic signature in the ionosphere. Adding the OTH Radar to the list of the “ionospheric seismometers” we discuss and compare the performances of the three different instruments mentioned above, namely HF Doppler sounding, GPS receivers and OTH radar.
Interannual variability of the Korea Strait Bottom Cold Water and its relationship with the upper water temperatures and atmospheric forcing in the Sea of Japan (East Sea)
Authors: Na Hanna , Kim Kwang‐Yul , Chang Kyung‐Il , Kim Kuh , Yun Jae‐Yul , Minobe Shoshiro
Published: September 2010

A 35 yearlong temperature data set is analyzed to investigate the long‐term temperature variability in the Korea Strait and its relationship with the temperature variability in the upper layer of the Sea of Japan (East Sea). The second cyclostationary empirical orthogonal function mode of the vertical temperature section in the Korea Strait describes the interannual variability of the Korea Strait Bottom Cold Water (KSBCW). According to the corresponding principal component time series, the strength of the KSBCW fluctuates yearly with a major spectral peak around 3 years. Multiple regression analysis shows that the interannual KSBCW variability is closely linked with the temperature variability in the southwestern region of the Sea of Japan (East Sea) at about 50–100 m depth. Along 40°N, the source of the KSBCW is traced at about 50 m, extending eastward from the east coast of Korea to about 135°E. At 37°N, the source is traced at a deeper level (about 50–100 m), confined more toward the east coast of Korea with a hint of double core characteristics. The interannual KSBCW variability is also related to the southward wind stress along the east coast of Korea. It appears that strong cooling/warming of upper water temperature induced by the basin‐scale wind stress results in the interannual KSBCW variability. This connection is verified by showing a reasonable interannual covariability between the KSBCW and the basin‐scale wind stress.
Gusev Crater, Mars: Observations of three dust devil seasons
Authors: Greeley Ronald , Waller Devin A. , Cabrol Nathalie A. , Landis Geoffrey A. , Lemmon Mark T. , Neakrase Lynn D. V. , Pendleton Hoffer Mary , Thompson Shane D. , Whelley Patrick L.
Published: September 2010

Spirit began operations in Gusev Crater in January 2004 and has returned data on three seasons of dust devil (DD) activity. Total DDs observed were 533 in season one, 101 in season two, and 127 in season three. Their general characteristics are the same within factors of 2 among the seasons, with median diameters of 19 m in season one, 24 m in season two, and 39 m in season three, and dust flux values for individual vortices ranging from 4.0 × 10−9 to 4.6 × 10−4 kg m−2 s−1 in season one, 5.2 × 10−7 to 6.2 × 10−5 kg m−2 s−1 in season two, and 1.5 × 10−7 to 1.6 × 10−4 kg m−2 s−1 in season three. All three seasons were initiated with the onset of southern Martian spring within 14 sols of the same Ls (181°) and their frequency increased to the period corresponding to late southern spring. The occurrences decreased monotonically in seasons one and three but apparently ended abruptly in season two when a large dust storm occurred; although the dusty atmosphere might have precluded the detection of active DDs, the abrupt cessation could result from conditions such as thermal stability of the atmosphere due to the presence of dust which could halt DD formation. Dust devils can contribute significant quantities of dust to the atmosphere, although it is unclear as to whether this dust stays locally or is injected into higher‐altitude winds and is distributed elsewhere. In the three DD seasons observed through Spirit, DDs in Gusev Crater injected a minimum average of ∼18 × 106 kg of material into the atmosphere each season.
Spirit Mars Rover Mission: Overview and selected results from the northern Home Plate Winter Haven to the side of Scamander crater
Authors: Arvidson R. E. , Bell J. F. , Bellutta P. , Cabrol N. A. , Catalano J. G. , Cohen J. , Crumpler L. S. , Des Marais D. J. , Estlin T. A. , Farrand W. H. , Gellert R. , Grant J. A. , Greenberger R. N. , Guinness E. A. , Herkenhoff K. E. , Herman J. A. , Iagnemma K. D. , Johnson J. R. , Klingelhöfer G. , Li R. , Lichtenberg K. A. , Maxwell S. A. , Ming D. W. , Morris R. V. , Rice M. S. , Ruff S. W. , Shaw A. , Siebach K. L. , de Souza P. A. , Stroupe A. W. , Squyres S. W. , Sullivan R. J. , Talley K. P. , Townsend J. A. , Wang A. , Wright J. R. , Yen A. S.
Published: September 2010

This paper summarizes Spirit Rover operations in the Columbia Hills, Gusev crater, from sol 1410 (start of the third winter campaign) to sol 2169 (when extrication attempts from Troy stopped to winterize the vehicle) and provides an overview of key scientific results. The third winter campaign took advantage of parking on the northern slope of Home Plate to tilt the vehicle to track the sun and thus survive the winter season. With the onset of the spring season, Spirit began circumnavigating Home Plate on the way to volcanic constructs located to the south. Silica‐rich nodular rocks were discovered in the valley to the north of Home Plate. The inoperative right front wheel drive actuator made climbing soil‐covered slopes problematical and led to high slip conditions and extensive excavation of subsurface soils. This situation led to embedding of Spirit on the side of a shallow, 8 m wide crater in Troy, located in the valley to the west of Home Plate. Examination of the materials exposed during embedding showed that Spirit broke through a thin sulfate‐rich soil crust and became embedded in an underlying mix of sulfate and basaltic sands. The nature of the crust is consistent with dissolution and precipitation in the presence of soil water within a few centimeters of the surface. The observation that sulfate‐rich deposits in Troy and elsewhere in the Columbia Hills are just beneath the surface implies that these processes have operated on a continuing basis on Mars as landforms have been shaped by erosion and deposition.
Alpha-Synuclein Aggregation Induced by Brief Ischemia Negatively Impacts Neuronal Survival in vivo: A Study in [A30P]alpha-Synuclein Transgenic Mouse
Authors: Unal-Cevik Isin , Gursoy-Ozdemir Yasemin , Yemisci Muge , Lule Sevda , Gurer Gunfer , Can Alp , Müller Veronica , Kahle Philip J , Dalkara Turgay
Published: September 2010

Alpha-synuclein oligomerization and aggregation are considered to have a role in the pathogenesis of neurodegenerative diseases. However, despite numerous in vitro studies, the impact of aggregates in the intact brain is unclear. In vitro, oxidative/nitrative stress and acidity induce α-synuclein oligomerization. These conditions favoring α-synuclein fibrillization are present in the ischemic brain, which may serve as an in vivo model to study α-synuclein aggregation. In this study, we show that 30-minute proximal middle cerebral artery (MCA) occlusion and 72 hours reperfusion induce oligomerization of wild-type α-synuclein in the ischemic mouse brain. The nonamyloidogenic isoform β-synuclein did not form oligomers. Alpha-synuclein aggregates were confined to neurons and colocalized with ubiquitin immunoreactivity. We also found that 30 minutes proximal MCA occlusion and 24 hours reperfusion induced larger infarcts in C57BL/6(Thy1)-h[A30P]alphaSYN transgenic mice, which have an increased tendency to form synuclein fibrils. Trangenics also developed more selective neuronal necrosis when subjected to 20 minutes distal MCA occlusion and 72 hours reperfusion. Enhanced 3-nitrotyrosine immunoreactivity in transgenic mice suggests that oxidative/nitrative stress may be one of the mechanisms mediating aggregate toxicity. Thus, the increased vulnerability of transgenic mice to ischemia suggests that α-synuclein aggregates not only form during ischemia but also negatively impact neuronal survival, supporting the idea that α-synuclein misfolding may be neurotoxic.
Silent Cortical Neuronal Damage in Atherosclerotic Disease of the Major Cerebral Arteries
Authors: Yamauchi Hiroshi , Nishii Ryuichi , Higashi Tatsuya , Kagawa Shinya , Fukuyama Hidenao
Published: September 2010

In atherosclerotic internal carotid artery (ICA) or middle cerebral artery (MCA) disease, hemodynamic compromise may cause selective neuronal damage manifested as loss of central benzodiazepine receptors (BZRs) in the normal-appearing cerebral cortex, without overt episode of stroke. To investigate the association of decreases in cortical BZRs with hemodynamic compromise and the effect of angiotensin receptor blockers (ARBs) on these receptors in patients whose atherosclerotic ICA or MCA disease is asymptomatic, we measured BZRs using positron emission tomography and 11C-flumazenil in 79 patients with asymptomatic atherosclerotic ICA or MCA disease and no cortical infarction. Three-dimensional stereotactic surface projections were used to calculate the BZR index, a measure of abnormally decreased BZRs in the cerebral cortex within the MCA distribution. Multiple regression analysis showed this index to be positively correlated with the value of oxygen extraction fraction, with the presence of silent subcortical infarcts, and with the presence of ischemic heart disease, whereas it was negatively correlated with the treatment of hypertension with ARBs. In asymptomatic atherosclerotic ICA or MCA disease, hemodynamic compromise is associated with selective neuronal damage manifested as decreases in cortical BZRs in the noninfarcted cerebral cortex, whereas ARBs are associated with preservation of cortical BZRs.
A nuclear glutathione cycle within the cell cycle
Authors: Diaz Vivancos Pedro , Wolff Tonja , Markovic Jelena , Pallardó Federico V. , Foyer Christine H.
Published: September 2010

The complex antioxidant network of plant and animal cells has the thiol tripeptide GSH at its centre to buffer ROS (reactive oxygen species) and facilitate cellular redox signalling which controls growth, development and defence. GSH is found in nearly every compartment of the cell, including the nucleus. Transport between the different intracellular compartments is pivotal to the regulation of cell proliferation. GSH co-localizes with nuclear DNA at the early stages of proliferation in plant and animal cells. Moreover, GSH recruitment and sequestration in the nucleus during the G1- and S-phases of the cell cycle has a profound impact on cellular redox homoeostasis and on gene expression. For example, the abundance of transcripts encoding stress and defence proteins is decreased when GSH is sequestered in the nucleus. The functions of GSHn (nuclear GSH) are considered in the present review in the context of whole-cell redox homoeostasis and signalling, as well as potential mechanisms for GSH transport into the nucleus. We also discuss the possible role of GSHn as a regulator of nuclear proteins such as histones and PARP [poly(ADP-ribose) polymerase] that control genetic and epigenetic events. In this way, a high level of GSH in the nucleus may not only have an immediate effect on gene expression patterns, but also contribute to how cells retain a memory of the cellular redox environment that is transferred through generations.
QHWM of the orthogonal type Lie subalgebra of the Lie algebra of matrix differential operators on the circle
Authors: Boyallian Carina , Meinardi Vanesa
Published: September 2010

In this paper we classify the irreducible quasifinite highest weight modules of the orthogonal Lie subalgebra of the Lie algebra of matrix differential operators on the circle. We also realize them in terms of the representation theory of the complex Lie algebra gℓ∞[m] of infinite matrices with a finite number of nonzero diagonals with entries in the algebra of truncated polynomials and the corresponding subalgebras of type B and D.
On the solution of the integral equation of scattering for finite range potentials
Authors: Cacciari Ilaria , Lantieri Marco , Moretti Paolo
Published: September 2010

In the problem of the scattering of a particle in the presence of a finite range central potential, the integral equation for the lth partial wave is studied. By using a matrix method, the exact external solutions are expressed in terms of the Fredholm determinant Δ, and the phase of Δ turns out to be equal to the phase shift. As an example, an array of delta-shell potentials is considered.
Experimental evaluation of the pressure and temperature dependence of ion-induced nucleation
Authors: Munir Muhammad Miftahul , Suhendi Asep , Ogi Takashi , Iskandar Ferry , Okuyama Kikuo
Published: September 2010

An experimental system for the study of ion-induced nucleation in a SO2/H2O/N2 gas mixture was developed, employing a soft x-ray at different pressure and temperature levels. The difficulties associated with these experiments included the changes in physical properties of the gas mixture when temperature and pressure were varied. Changes in the relative humidity (RH) as a function of pressure and temperature also had a significant effect on the different behaviors of the mobility distributions of particles. In order to accomplish reliable measurement and minimize uncertainties, an integrated on-line control system was utilized. As the pressure decreased in a range of 500–980 hPa, the peak concentration of both ions and nanometer-sized particles decreased, which suggests that higher pressure tended to enhance the growth of particles nucleated by ion-induced nucleation. Moreover, the modal diameters of the measured particle size distributions showed a systematic shift to larger sizes with increasing pressure. However, in the temperature range of 5–20 °C, temperature increases had no significant effects on the mobility distribution of particles. The effects of residence time, RH (7%–70%), and SO2 concentration (0.08–6.7 ppm) on ion-induced nucleation were also systematically investigated. The results show that the nucleation and growth were significantly dependent on the residence time, RH, and SO2 concentration, which is in agreement with both a previous model and previous observations. This research will be inevitable for a better understanding of the role of ions in an atmospheric nucleation mechanism.
A study of eukaryotic response mechanisms to atmospheric pressure cold plasma by using Saccharomyces cerevisiae single gene mutants
Authors: Feng Hongqing , Wang Ruixue , Sun Peng , Wu Haiyan , Liu Qi , Fang Jing , Zhu Weidong , Li Fangting , Zhang Jue
Published: September 2010

The mechanisms of eukaryotic cell response to cold plasma are studied. A series of single gene mutants of eukaryotic model organism Saccharomyces cerevisiae are used to compare their sensitivity to plasma treatment with the wild type. We examined 12 mutants in the oxidative stress pathway and the cell cycle pathway, in which 8 are found to be hypersensitive to plasma processing. The mutated genes’ roles in the two pathways are analyzed to understand the biological response mechanisms of plasma treatment. The results demonstrate that genes from both pathways are needed for the eukaryotic cells to survive the complex plasma treatment.
Effect of blend layer morphology on performance of ZnPc:C60-based photovoltaic cells
Authors: Zeng Wenjin , Yong Kian Soon , Kam Zhi Ming , Zhu Furong , Li Yuning
Published: September 2010

Zinc phthalocyanine (ZnPc): fullerene-C60 (C60)-based organic photovoltaic (OPV) with high power conversion efficiency (PCE) are fabricated. Homogeneously distributed grains of ∼40–50 nm are observed for the ZnPc:C60 blend layer deposited on bare indium-tin oxide (ITO) substrates. In contrast, the blend layer form grains of smaller lateral extensions (∼20–30 nm) on 3, 4-polyethylenedioxythiophene: polystyrenesulfonate modified ITO substrates. OPV fabricated on the former substrates show PCE of up to 3.9% that is about twice the PCE (1.9%) obtained for the devices on the latter substrates. This effect can be explained by better transport properties and reduced charge recombination of the blend layer on the bare ITO.
Phase changes of CO2 hydrate under high pressure and low temperature
Authors: Hirai Hisako , Komatsu Kazuki , Honda Mizuho , Kawamura Taro , Yamamoto Yoshitaka , Yagi Takehiko
Published: September 2010

High pressure and low temperature experiments with CO2 hydrate were performed using diamond anvil cells and a helium-refrigeration cryostat in the pressure and temperature range of 0.2–3.0 GPa and 280–80 K, respectively. In situ x-ray diffractometry revealed that the phase boundary between CO2 hydrate and water+CO2 extended below the 280 K reported previously, toward a higher pressure and low temperature region. The results also showed the existence of a new high pressure phase above approximately 0.6 GPa and below 1.0 GPa at which the hydrate decomposed to dry ice and ice VI. In addition, in the lower temperature region of structure I, a small and abrupt lattice expansion was observed at approximately 210 K with decreasing temperature under fixed pressures. The expansion was accompanied by a release of water content from the sI structure as ice Ih, which indicates an increased cage occupancy. A similar lattice expansion was also described in another clathrate, SiO2 clathrate, under high pressure. Such expansion with increasing cage occupancy might be a common manner to stabilize the clathrate structures under high pressure and low temperature.
On the infimum of bounded quantum observables
Authors: Xu Xiao-Ming , Du Hong-Ke , Fang Xiaochun
Published: September 2010

The set of all bounded observables corresponding to a quantum system is usually represented by S(H), the set of all bounded linear self-adjoint operators on a Hilbert space H. In 2006, Gudder introduced a logic order on S(H). Given A, B∊S(H), let A∧B be the greatest lower bound (infimum) of A and B with respect to the Gudder order. In this paper, we characterize A∧B using the invariant subspaces of A and B.
Straining of SiGe ultrathin films with mesoporous Si substrates
Authors: Boucherif A. , Blanchard N. P. , Marty O. , Regreny P. , Guillot G. , Grenet G. , Lysenko V.
Published: September 2010

We report on the fabrication and characterization of ultrathin (down to 50 nm) tensile strained SiGe films on mesoporous Si substrates. Low temperature oxidation of the porous substrate relaxes the compressive strain in the as grown monocrystalline (mc) SiGe. Applying this method to a 50 nm thick mc-Si0.72Ge0.28 film, a tensile strain >0.78% can be achieved without compromising crystalline quality and up to 1.45 % without the appearance of cracks.
A tunable universal terahertz filter using artificial dielectrics based on parallel-plate waveguides
Authors: Mendis Rajind , Nag Abhishek , Chen Frank , Mittleman Daniel M.
Published: September 2010

Using parallel-plate waveguides (PPWGs) that mimic artificial dielectrics, we demonstrate a universal filter that provides low-pass, high-pass, band-pass, and band-stop (or notch) filtering functionalities in the terahertz (THz) frequency regime. The device essentially consists of two PPWGs in a complementary geometry. The filtering functionality is achieved by positioning an appropriate amplitude mask in the path of the spatially chirped THz beam between the two waveguides. By varying the position of the mask, we experimentally and theoretically demonstrate continuous tunability of the respective 3 dB cutoff frequencies within the frequency range from about 0.3 to 0.7 THz.
Surface states induced high P-type conductivity in nanostructured thin film composed of Ge nanocrystals in SiO2 matrix
Authors: Zhang B. , Shrestha S. , Green M. A. , Conibeer G.
Published: September 2010

Highly conductive thin films composed of Ge nanocrystals (Ge-NCs) embedded in SiO2 matrix were prepared using a low thermal budget process. P-type behavior in the undoped films was attributed to the hole accumulation caused by acceptor-like surface states. Quantitative analysis has demonstrated that the density of surface states was sufficient to cause the measured electrical conductivity. The charge transport mechanism was identified as thermally activated charge hopping from one NC to its nearest neighbor. Postgrowth rapid thermal annealing dramatically increased the conductivities and this was tentatively explained by the modification of Ge-NCs’ surface structure and reduction in defects in SiO2 matrix.
Experimental measurement of the mobilities of atomic and dimer Ar, Kr, and Xe ions in their parent gases
Authors: Neves P. N. B. , Conde C. A. N. , Távora L. M. N.
Published: September 2010

A new experimental technique for measuring the mobilities of positive ions in their parent gases is presented. The technique was applied to the rare gases, Ar, Kr, and Xe, and, for pressures typically below 10 Torr, two different types of positive ions were observed. The reduced mobilities of these ions in their parent gases were measured as a function of E/N, the ratio of the electric field strength to the gas number density, at a temperature of 300±1 K. The results were compared with others available in the literature and the two ions were identified as being the atomic and the dimer rare gas ions. The results are in good agreement with those from other authors. Space charge and impurities effects are discussed.