bluuebunny/crossref_metadata_2025 huggingface dataset:
Spaces of Performance in the New Moscow: the Case of Theatre Square
Authors: SIEMENS ELENA
Published: November 2005

Combining critical analysis, personal accounts, and original photography, this essay discusses Theatre Square, Moscow's most prominent theatrical destination, and examines the dramatic changes it underwent in the Soviet era, as well as after the demise of the Soviet Union. In following Yury Lotman's notion of the ‘ensemble’, I argue that the recent reconstruction of the garden in front of the Bolshoi Theatre created a particular set of conditions under which the difference between the ‘diversely encoded’ landmarks of Theatre Square became less relevant. The article also looks into whether the new and newly reconstructed gardens and parks of post-Soviet Moscow detract from, as some critics have suggested, or on the contrary contribute to, the act of remembering the past.
The Values of a Festival – the Swedish Theatre Biennale 2003
Authors: SAUTER WILLMAR
Published: November 2005

The Swedish Theatre Biennale is a peculiar festival in the sense that it lacks a public audience. More than a thousand theatre professionals gather for four days to present and watch the most exciting productions of the last two years in between lectures, debates, master classes and coffee breaks. There is hardly any room for local visitors to see a performance. Nevertheless, the hosting city sponsors the festival, newspapers report on it and the citizens look amazed at the crowd of known and unknown artists. What are the values of such a festival? Why is it held every two years and who benefits from it? These questions are pursued in this article according to a model of the theatrical event as presented in the introduction of the International Federation for Theatre Research (IFTR) book publication Theatrical Events –; Borders, Dynamics, Frames (2004). Politics, management, environment and experiences are juxtaposed as equally important elements of the festival as a theatrical event. The article is concluded by an expanded model pointing out some of the values at stake.
Community Building within a Festival Frame: Working-Class Celebrations in Germany, 1918–1933
Authors: WARSTAT MATTHIAS
Published: November 2005

The concept of festival can help to understand the framework within which political community building took place in Germany in the late nineteenth and early twentieth century and the methods employed in doing so. Political communities were established within different kinds of cultural performances such as gatherings, demonstrations, party conventions, and – most frequently – political celebrations, which obtained a festival-like structure. Referring to examples from the labour movement, this article examines different techniques of creating communities and discusses the impact of theatrical strategies and certain types of theatre in this crucial field of modern politics.
The Israeli National Community Theatre Festival: the Real and the Imagined
Authors: LEV-ALADGEM SHULAMITH
Published: November 2005

This article focuses on the National Community Theatre in Israel in order to demonstrate what happens when co-communities (marginal communities) appropriate the concept and the rules of the game of festival to their own benefit. Community theatre in Israel is a means of self-representation within co-communities that usually exist on the geographical, social, political and artistic margins of the public sphere. The National Community Theatre Festival is thus a subversive tactic by which the powerless groups present their move from the margins to the centre and transform themselves to visible social agents. This Festival then celebrates the latent potential for social activism that these groups have when they are coming together and imagine themselves powerful, united and prestigious.
Implementing clarification dialogues in open domain question answering
Authors: DE BONI MARCO , MANANDHAR SURESH
Published: November 2005

We examine the implementation of clarification dialogues, a mechanism for ensuring that question answering systems take into account user goals by allowing them to ask series of related questions either by refining or expanding on previous questions with follow-up questions, in the context of open domain Question Answering systems. We develop an algorithm for clarification dialogue recognition through the analysis of collected data on clarification dialogues and examine the importance of clarification dialogue recognition for question answering. The algorithm is evaluated and shown to successfully recognize the start and continuation of clarification dialogues in 94% of cases. We then show the usefulness of the algorithm by demonstrating how the recognition of clarification dialogues can simplify the task of answer retrieval.
Segmenting documents by stylistic character
Authors: GRAHAM NEIL , HIRST GRAEME , MARTHI BHASKARA
Published: November 2005

As part of a larger project to develop an aid for writers that would help to eliminate stylistic inconsistencies within a document, we experimented with neural networks to find the points in a text at which its stylistic character changes. Our best results, well above baseline, were achieved with time-delay networks that used features related to the author's syntactic preferences, whereas low-level and vocabulary-based features were not found to be useful. An alternative approach with character bigrams was not successful.
Longitudinal structure of the equatorial anomaly in the nighttime ionosphere observed by IMAGE/FUV
Authors: Sagawa E. , Immel T. J. , Frey H. U. , Mende S. B.
Published: November 2005

The Far Ultraviolet Imager (FUV) on board the IMAGE satellite provides an instantaneous global view of the OI 135.6‐nm nightglow with 2 min time resolution. Because the OI 135.6‐nm emission from the nighttime ionosphere is determined by the line‐of‐sight integrated plasma density, the nightglow images are useful for studying the nighttime low‐latitude ionosphere globally. With the IMAGE/FUV 135.6‐nm observations from March to June 2002, we have examined the global characteristics of the nighttime equatorial anomaly (EA) by constructing a constant local time map (LT map), in which pixels within an assigned local time range are extracted from the IMAGE/FUV nightglow images obtained over an observation period of 3 days or more and are put together to compose a global distribution map of emission intensities at that local time. These LT maps show that the development of the EA has a significant longitudinal structure, in which peaks and dips of the crest emission intensity and the crest latitude have about 90° longitudinal separation in the longitude range from 0° to 250°. Although there is not enough data over the American sector, this result suggests that the EA longitudinal structure has a prominent zonal component of the wave number 4. The observed longitudinal structure of the nighttime EA could not be fully explained by factors such as the empirical electric field and neutral wind models, the geomagnetic declination angle, or the displacement of the geomagnetic equator from the geographic equator. To explain the observed longitudinal structure of the EA, in particular, the wave number 4 feature, we may need to consider other forcing, for example, nonmigrating tide originated from the lower atmosphere.
Revised time‐of‐flight calculations for high‐latitude geomagnetic pulsations using a realistic magnetospheric magnetic field model
Authors: Wild J. A. , Yeoman T. K. , Waters C. L.
Published: November 2005

We present a simple time‐of‐flight analysis of Alfvén pulsations standing on closed terrestrial magnetic field lines. The technique employed in this study in order to calculate the characteristic period of such oscillations builds upon earlier time‐of‐flight estimates via the implementation of a more recent magnetospheric magnetic field model. In this case the model employed is the Tsyganenko (1996) field model, which includes realistic magnetospheric currents and the consequences of the partial penetration of the interplanetary magnetic field into the dayside magnetopause. By employing a simple description of magnetospheric plasma density, we are therefore able to estimate the period of standing Alfvén waves on geomagnetic field lines over a significantly wider range of latitudes and magnetic local times than in previous studies. Furthermore, we investigate the influence of changing season and upstream interplanetary conditions upon the period of such pulsations. Finally, the eigenfrequencies of magnetic field lines computed by the time‐of‐flight technique are compared with corresponding numerical solutions to the wave equation and experimentally observed pulsations on geomagnetic field lines.
Mesoscale circulations and atmospheric CO2 variations in the Tapajós Region, Pará, Brazil
Authors: Lu Lixin , Denning A. Scott , da Silva‐Dias Maria Assuncao , da Silva‐Dias Pedro , Longo Marcos , Freitas Saulo R. , Saatchi Sassan
Published: November 2005

We have investigated mesoscale circulations and atmospheric CO2 variations over a heterogeneous landscape of forests, pastures, and large rivers during the Santarém Mesoscale Campaign (SMC) of August 2001. The atmospheric CO2 concentration variations were simulated using the Colorado State University Regional Atmospheric Modeling System with four nested grids that included a 1‐km finest grid centered on the Tapajós National Forest. Surface CO2 fluxes were prescribed using idealized diurnal cycles over forest and pasture that derived from flux tower observations; while surface water CO2 efflux was prescribed using a value suggested by in situ measurements in the Amazon region. Our simulation ran from 1 August through 15 August 2001, which was concurrent with the SMC. Evaluation against flux tower observations and Belterra meteorological tower measurements showed that the model captured the observed 2‐m temperatures and 10‐m winds reasonably well. At 57 m the model reproduced the daytime CO2 concentration better than the nighttime concentration but missed the observed early morning CO2 maxima, in part because of the difficulties of simulating stable nocturnal boundary conditions and subgrid‐scale intracanopy processes. The results also suggested that the topography, the differences in roughness length between water and land, the “T” shape juxtaposition of Amazon and Tapajós Rivers, and the resulting horizontal and vertical wind shears all facilitated the generation of local mesoscale circulations. Possible mechanisms producing a low‐level convergence (LLC) line near the east bank of the Tapajós River were explored. Under strong trade wind conditions, mechanical forcing is more important than thermal forcing in LLC formation. Persistent clouds near the east side of the Tapajós River may have a significant impact on observed ecosystem carbon flux and should be taken into account if tower fluxes are to be generalized to a larger region.
Contrasts in the effects on climate of anthropogenic sulfate aerosols between the 20th and the 21st century
Authors: Dufresne J.‐L. , Quaas J. , Boucher O. , Denvil S. , Fairhead L.
Published: November 2005

In this study, we examine the time evolution of the relative contribution of sulfate aerosols and greenhouse gases to anthropogenic climate change. We use the new IPSL‐CM4 coupled climate model for which the first indirect effect of sulfate aerosols has been calibrated using POLDER satellite data. For the recent historical period the sulfate aerosols play a key role on the temperature increase with a cooling effect of 0.5 K, to be compared to the 1.4 K warming due to greenhouse gas increase. In contrast, the projected temperature change for the 21st century is remarkably independent of the effects of anthropogenic sulfate aerosols for the SRES‐A2 scenario. Those results are interpreted comparing the different radiative forcings, and can be extended to other scenarios. We also highlight that the first indirect effect of aerosol strongly depends on the land surface model by changing the cloud cover.
Overview of the ICESat Mission
Authors: Schutz B. E. , Zwally H. J. , Shuman C. A. , Hancock D. , DiMarzio J. P.
Published: November 2005

The Geoscience Laser Altimeter System (GLAS) on the NASA Ice, Cloud and land Elevation Satellite (ICESat) has provided a view of the Earth in three dimensions with unprecedented accuracy. Although the primary objectives focus on polar ice sheet mass balance, the GLAS measurements, distributed in 15 science data products, have interdisciplinary application to land topography, hydrology, vegetation canopy heights, cloud heights and atmospheric aerosol distributions. Early laser life issues have been mitigated with the adoption of 33‐day operation periods, three times per year, designed to document intra‐ and inter‐annual polar ice changes in accordance with mission requirements. A variety of calibration/validation experiments have been executed which show that the elevation products, when fully calibrated, have an accuracy that meets the science requirements. The series of papers in this special ICESat issue demonstrate the utility and quality of the ICESat data.
Updated regional precipitation and temperature changes for the 21st century from ensembles of recent AOGCM simulations
Authors: Giorgi F. , Bi X.
Published: November 2005

We present an analysis of regional precipitation and temperature changes for different 20‐year periods (20 yrp) of the 21st century from the latest ensemble of global model simulations (20 models) over 26 land regions worldwide and 3 IPCC emission scenarios (A1B, A2, B1). We find that regional warming enhancements and precipitation changes are mostly in agreement with previous generation models (with some notable exceptions). A high level of agreement of weighted ensemble average regional changes is found across scenarios and across different periods within the 21st century. Overall, both for temperature and precipitation, the dry seasons appear generally more responsive to GHG forcing than the wet seasons. Our results indicate that the precipitation and temperature change projections produced by ensembles of current global model simulations show increasingly consistent regional patterns.
Clues to variability in Arctic minimum sea ice extent
Authors: Francis Jennifer A. , Hunter Elias , Key Jeffrey R. , Wang Xuanji
Published: November 2005

Perennial sea ice is a primary indicator of Arctic climate change. Since 1980 it has decreased in extent by about 15%. Analysis of new satellite‐derived fields of winds, radiative forcing, and advected heat reveals distinct regional differences in the relative roles of these parameters in explaining variability in the northernmost ice edge position. In all six peripheral seas studied, downwelling longwave flux anomalies explain the most variability – approximately 40% – while northward wind anomalies are important in areas north of Siberia, particularly earlier in the melt season. Anomalies in insolation are negatively correlated with perennial ice retreat in all regions, suggesting that the effect of solar flux anomalies is overwhelmed by the longwave influence on ice edge position.
Late Quaternary aeolian activity in the Mu Us and Otindag dune fields (north China) and lagged response to insolation forcing
Authors: Lu Huayu , Miao Xiaodong , Zhou Yali , Mason Joseph , Swinehart James , Zhang Jiafu , Zhou Liping , Yi Shuangwen
Published: November 2005

Dune fields in parts of northern China contain important stratigraphic records of late Quaternary change in the East Asian monsoon. In this study, 33 new optically stimulated luminescence (OSL) ages and other measurements from aeolian sediment sections are used to reconstruct the timing of wet‐dry climate variation in the Mu Us and Otindag dune fields of north China. The results indicate dune activity and dry climate in the last few hundred years, 14 ka to about 7–8 ka, and 50 ka to 60 ka. The dunes were mainly stable, implying a wetter climate, between about 7–8 ka and 2.4 ka. These results imply a lag of several thousand years between peak summer insolation at 10–11 ka and high summer monsoon rainfall after 7–8 ka. In the investigated regions, the monsoon climate may not respond directly to orbital forcing over millennial time scales. Land surface feedbacks may account for lagged dune field response.
Three‐dimensional estimation of electron density over Japan using the GEONET GPS network combined with SAC‐C data and ionosonde measurements
Authors: Garcia‐Fernandez M. , Saito A. , Juan J. M. , Tsuda T.
Published: November 2005

The work presented here proposes a local tomographic approach to obtain a three‐dimensional description of the ionospheric electron density over Japan. To do this, a combination of GPS and ionosonde data is used in order to take advantage of the strong points of each data type. The GPS data is composed of ground and SAC‐C Low Earth Orbiter observations. The ground observations correspond to measurements of 99 receivers (out of about 1000) from the dense Japanese GPS network (GEONET). SAC‐C GPS limb sounding observations are processed to obtain vertical profiles of electron density. For this purpose, an improved approach of Abel inversion that considers Vertical Total Electron Content data has been used to overcome the assumption of spherical symmetry. The resulting profiles have been averaged to build a set of background profiles, which are rescaled with the ionospheric NmF2 values sounded by the Japanese network of four ionosondes and used by the tomographic algorithm to provide with vertical description of electron density. For the validation of this tomographic approach, the hourly values of NmF2 given by the four Japanese ionosondes and the vertical profiles of electron density measured by the MU Radar in Shigaraki (during the sounding campaign of November 2002) have been used. This validation with independent data shows relative discrepancies about 25% and, moreover, it shows that the use of the profiles obtained from SAC‐C data offers an improvement on the dawn, dusk, and nighttime bottomside and topside estimations of the electron density with respect to the case of using the IRI model.
Multiple spacecraft observations of energetic ions during a high solar wind pressure event
Authors: Chen Jiasheng , Fritz Theodore A. , Sheldon Robert B.
Published: November 2005

On 28 June 1999 the Wind spacecraft (near the forward libration point) observed a large solar wind pressure spike from 0445 UT to 0600 UT. The Polar satellite at 7 hours magnetic local time detected an energetic particle event in the high‐altitude region associated with turbulent diamagnetic cavities from 0512 UT to 0627 UT. The particles and cavities are very similar to those that were previously found in the high‐altitude dayside cusp region. They are independent of both the solar wind velocity and the interplanetary magnetic field (IMF) vectors. The enhancements of the magnetic field fluctuations in the ultra‐low frequency range measured by the Wind were also observed by the Polar. Most of the time, during the event period, the IMF had a duskward component, suggesting that cusp diamagnetic cavities also existed in the postnoon sector in the Northern Hemisphere. Energetic ions of both ionospheric origin and solar wind origin were observed by the Polar spacecraft during this event period. The He++/H+ ratio in the diamagnetic cavities was a factor of four higher than in the quasi‐trapping region before the event onset, while the He+/He++ ratio in the cavities was more than one order of the magnitude lower. In this event, the measured cusp ions had energies up to 4 MeV. No clear relationship between the cusp energetic ion flux and the IMF cone angle was found. The Interball 1 spacecraft located just upstream of the bow shock in the prenoon sector measured an upstream ion event from about 0516 UT to 0600 UT. The onset of the energetic ions observed by Interball 1 in the upstream event was the same for different energies; the ion energy spectra were independent of the solar wind velocity and their intensities were independent of the bow shock geometry and the solar wind density. The energetic ion event onset was first detected in the cusp by Polar at 0512 UT, then near the bow shock in the prenoon by Interball 1 at 0516 UT, and then in the far upstream by Wind at 0523 UT. The measured energetic ion intensity decreased with increasing distance from the cusp diamagnetic cavities. These observational facts together with the IMF directions suggest that (1) this large solar wind pressure event produced an extremely large diamagnetic cavity (>10 RE) within the magnetosphere, (2) the bow shock was not the main source of both the cusp and upstream energetic ions, and (3) the upstream energetic ions most likely came from the cusp.
A three‐dimensional analysis of global propagation of magnetohydrodynamic (MHD) waves in a structured solar atmosphere
Authors: Wu S. T. , Li B. , Wang S. , Zheng Huinan
Published: November 2005

A three‐dimensional compressible magnetohydrodynamic (MHD) simulation in the spherical coordinates is presented for the propagation of MHD waves in a structured solar atmosphere by using the fractional step method. An initial magnetic field profile that has the characteristics of the open configuration at the pole and closed configuration at the equator is used. The initial state of the solar atmosphere consists of the chromosphere and corona; thus the transition region from the photosphere is approximated. The purpose of this study is to understand the nature of propagation MHD waves in a two‐layer solar atmosphere. Thus a pressure pulse is added at the bottom of the chromosphere (i.e., r = 1 Rs). We compare the response of this case with one in which we introduce the pulse at the bottom of the corona (i.e., r = 1.018 Rs). We find that (1) where the disturbance is initiated at the bottom of the chromosphere, a pair of fast mode waves and a slow mode MHD wave are generated. The pair of fast mode MHD waves are expansion waves and their propagation speeds increase with increasing height, (2) if the disturbance is initiated at the bottom of the corona, (r = 1.018 Rs), we observed a pair of fast and slow mode MHD waves propagating upward to the corona and another pair propagating downward toward the photosphere, respectively. We suggest that the model has the potential to be used to show the correspondence between observed flare initiation Moreton waves of the chromosphere and Extreme Ultraviolet Imaging Telescope waves in the low corona.
East‐west asymmetries of the equatorial electrojet 8.3 m type‐2 echoes observed over Trivandrum and a possible explanation
Authors: Patra A. K. , Tiwari D. , Devasia C. V. , Pant T. K. , Sridharan R.
Published: November 2005

The east‐west asymmetries in the spectral parameters of the type‐2 echoes from the equatorial electrojet plasma irregularities observed using a 18 MHz radar from Trivandrum are presented. Observations show that the difference in signal strength, velocity, and spectral width of the type‐2 echoes observed in the west and east beam are as high as 15 dB, 60 m s−1, and 70 m s−1, respectively. Further, the asymmetry in velocity increases with height, while the asymmetries in signal strength and spectral width decrease with height. While the velocity asymmetry is consistent with the past results, the asymmetries in signal strength and spectral width of the type‐2 echoes are significant new results, not reported earlier. Finite vertical drift velocities of the irregularities, associated with the primary wave structures, are found to be responsible for the observed east‐west velocity asymmetry. The asymmetries in signal strength and spectral width are attributed to the orientation of kilometer‐scale plasma waves present in the equatorial electrojet. Finally, a unified picture is presented to show that the properties of the kilometer‐scale waves are the ones that are responsible for all three asymmetries observed in the spectral parameters of the type‐2 echoes.
Reply to the comment by P. Song et al. on “Steady state slow shock inside the Earth's magnetosheath: To be or not to be? 1. The original observations revisited” by D. Hubert and A. Samsonov
Authors: Hubert D. , Samsonov A.
Published: November 2005

Among the 18 supposed slow mode transition (SMT) cases identified by Song et al. [1990, 1992], Hubert and Samsonov [2004, see section 3] concluded that ten cases needed to be rejected. From the remaining eight candidates for SMT events, it was shown that temporal variations of the interplanetary magnetic field (IMF) play a key role in the origin and nature of the density enhancement in the supposed SMT. The exogenous origin of the supposed SMT was therefore established. Hubert and Samsonov [2004] explained how only two cases could be simulated. Song et al. (SRGTE hereafter) elected to dispute three of the eight cases which have been analyzed in great detail by Hubert and Samsonov [2004] and/or simulated in a three‐dimensional (3‐D) MHD model [Samsonov and Hubert, 2004].
A simple axisymmetric model of magnetosphere‐ionosphere coupling currents in Jupiter's polar ionosphere
Authors: Cowley S. W. H. , Alexeev I. I. , Belenkaya E. S. , Bunce E. J. , Cottis C. E. , Kalegaev V. V. , Nichols J. D. , Prangé R. , Wilson F. J.
Published: November 2005

We propose a simple illustrative axisymmetric model of the plasma flow and currents in Jupiter's polar ionosphere which are due both to internal magnetospheric plasma processes and the solar wind interaction. The plasma flow in the model is specified using a combination of observations, previous modeling, and theory, and the ionospheric and field‐aligned currents are then calculated. With increasing latitude, the model represents conditions in the inner, middle, and outer magnetosphere on closed field lines and on open field lines mapping to the tail lobes. The model allows us to address three important topics, concerned with the closure of the upward field‐aligned currents flowing in the middle magnetosphere region, the energy transfers from planetary rotation to polar upper atmosphere heating and to the magnetosphere, and the relative significance of auroral processes associated with the boundary of open field lines (and hence with the solar wind interaction) and with the middle magnetosphere. It is shown in particular that the energy transfers to the polar upper atmosphere and magnetosphere are of order hundreds of TW each and that discrete auroral precipitation is expected both at the boundary of open field lines and in the middle magnetosphere, though being dominated by the latter. While the initial calculations assume for simplicity a constant ionospheric conductance, we also present a development of the model in which the conductance is self‐consistently increased in regions of upward field‐aligned current by the precipitation of accelerated electrons. It is shown that this feedback acts to spread the upward current in the region equatorward of the open field line boundary, thus reducing the energy flux and total power of precipitating auroral electrons in this region. At the same time it concentrates the upward current in the equatorward part of the middle magnetosphere, thereby increasing the energy flux and total power of precipitating electrons in this region.
Solar wind‐magnetosphere coupling leading to relativistic electron energization during high‐speed streams
Authors: Lyons L. R. , Lee D.‐Y. , Thorne R. M. , Horne R. B. , Smith A. J.
Published: November 2005

Enhancements in relativistic electron fluxes in the outer radiation belt often occur following magnetic storms and have been suggested to result from resonant interactions with enhanced whistler‐mode chorus emissions observed on the dawnside. Using observations during a period of persistent high‐speed, corotating, solar wind streams, we investigate the aspects of solar wind‐magnetosphere coupling that lead to these enhanced chorus emissions. We find that relativistic electron energization occurs in association with large‐amplitude Alfvén waves within the high‐speed streams. These waves last for multiday periods and cause multiday intervals having intermittent periods of significantly enhanced convection. The enhanced convection periods are followed by repetitive substorm onsets caused by the Alfvén wave related repetitive reductions in convection. We use these substorm onsets, identified using geosynchronous particles and midlatitude H components, as indicators of preceding periods of enhanced convection and of reductions in convection. We use ground‐based chorus observations from the Halley station VLF/ELF Logger Experiment (VELOX) instrument to indicate magnetospheric chorus intensities. These data give evidence that the periods of enhanced convection that precede substorm expansions lead to the enhanced dawnside chorus wave. We also see that the enhanced solar wind densities nsw ahead of high‐speed streams are associated with significant energetic electron loss at geosynchronous orbit and that the subsequent flux increases appear to not begin until nsw drops below ∼5 cm−3 even if the solar wind speed increases earlier. The sequence of loss during the leading interval of high nsw, followed by energization during high‐speed streams, occurs whether or not the high nsw interval leads to a magnetic storm.
Extinction of UV‐visible radiation in wet midlatitude (maritime) snow: Implications for increased NOx emission
Authors: Fisher F. N. , King M. D. , Lee‐Taylor J.
Published: November 2005

A field and modeling study of the optical properties of wet midlatitude (maritime) mountainous snowpack is presented. The snowpacks were found to have greater UV penetration depths than polar (tundra) snowpacks and consequently may release more NO2 gas to the atmosphere during the photolytic destruction of nitrate anions in the snowpack for a given spherical irradiance. Fluxes of NO2 to the troposphere as a result of NO3− photolysis were calculated for different measured e‐folding depths using tropospheric ultraviolet‐visible (TUV)–modeled actinic flux data assuming all the NO2 can leave the snowpack and the photolysis of nitrate is the rate‐limiting step. These calculated fluxes ranged from 3.3 to 7.6 kg km−2 yr−1 (assuming 150 days of snow cover a year), significantly more than polar snowpacks by a factor of 4–10. The fieldwork measured liquid equivalent e‐folding depths of 3.74–14.66 cm (e‐folding depths of 7.25–32.4 cm−1) at four sites in the Cairngorm mountain range, Scotland (57°07′N, 3°40′W), during the winter of 2003. The wavelength range studied was 300–450 nm. The snowpacks consisted predominantly of windblown rounded grains ranging from 0.1 to 1.5 mm in diameter. The liquid water content of the snowpacks varied between the sites, which were visited up to three times to observe temporal changes in the physical composition and optical properties of the snowpack. The snowpack was modeled using the TUV radiative‐transfer model, calculating scattering cross sections (σscatt) between 1 and 5 m2 kg−1. The absorption coefficient due to impurities (σabs+) was also modeled and was found to be approximately 1.0 cm2 kg−1. Three optically different snowpack categories are suggested: cold, dry polar (tundra) snowpacks, σscatt = 20–30 m2 kg−1; warmer polar coastal (maritime) snowpacks, σscatt = 6–13 m2 kg−1; and melting midlatitude mountainous (maritime) snow, σscatt = 1–5 m2 kg−1. Thus for midlatitude wet snow, 85% of photochemistry is likely to occur in the top 15–60 cm.
Forest fire aerosol over the Mediterranean basin during summer 2003
Authors: Pace G. , Meloni D. , di Sarra A.
Published: November 2005

Observations at Lampedusa show that long‐lasting intense episodes of fine (Ångström exponent, α, > 1.5) light absorbing aerosol occurred in the central Mediterranean during summer 2003, along with exceptionally hot and dry conditions throughout continental Europe and the Mediterranean basin. The absorbing particles appear to be produced mostly by large‐scale intense forest fires in southern Europe. In this paper Moderate Resolution Imaging Spectroradiometer (MODIS) observations are used to determine the spatial and temporal extent of the summer 2003 forest fire aerosol episode over the Mediterranean sea. MODIS observations are first compared to measurements obtained with a multifilter rotating shadowband radiometer, MFRSR, at Lampedusa in July and August 2003. Values of the optical depth, τ, at 550 nm show a good agreement (linear correlation coefficient of 0.67, slope of 0.85). Ångström exponents retrieved from MODIS are larger than those from MFRSR at low values of α and are smaller than those from MFRSR at high values of α. In addition to Lampedusa, five other open sea locations representative of different sectors of the Mediterranean basin were chosen to study the evolution of the aerosol properties during July and August 2003. MODIS observations reveal that particles displaying α > 1.3 and relatively large aerosol optical depth are present at four out of the six locations for an extended period (11–16 days) in August. Trajectories ending at the four locations show that in all cases, air masses overpass active fires in southern Europe. MODIS observations between 2000 and 2004 show that the summer 2003 forest fire aerosol episode was the longest lasting and covered the largest area. Normally, summertime episodes lasted about 4–6 days and only covered two locations at a time. The aerosol optical properties observed at Lampedusa are used as input to a radiative transfer model to estimate the absorbing aerosol radiative effects. Aerosol radiative forcing in the 300–800 nm range and atmospheric heating rates are calculated assuming different aerosol vertical distributions. It is estimated that forest fire particles produce an increase in heating rate as large as 2.8 K/day at 20° solar zenith angle at the altitude of the aerosol layer. This large heating may have increased the atmospheric stability that helped to maintain the anomalously hot and dry conditions during summer 2003.
Simultaneously retrieving cloud optical depth and effective radius for optically thin clouds
Authors: Min Qilong , Duan Minzheng
Published: November 2005

A new technique for simultaneously retrieving cloud optical depth and effective radius has been proposed. This approach is based on the angular distribution of scattered light in the forward scattering lobe of cloud drops. The angular distributions can be observed by multiple shadowband scans. Radiative transfer modeling simulations demonstrate that accuracies for cloud optical depth, effective radius, and liquid water path are 2%, 10%, and 2 gm−2, respectively, for given possible instrument noise and uncertainties. Further, we have tested different measurement strategies and achieved consistent accuracies. This technique will provide an approach to deal with the issue of “CLOWD (cloud with low optical (water) depth).”
Mechanical unfolding of ubiquitin molecules
Authors: Cieplak Marek , Marszalek Piotr E.
Published: November 2005

Mechanical stretching of ubiquitin and of its several repeats are studied through molecular-dynamics simulations. A Go-type model [H. Abe and N. Go, Biopolymers 20, 1013 (1981)] with a realistic contact map and with Lennard-Jones contact interactions is used. The model qualitatively reproduces the experimentally observed differences between force-extension patterns obtained on polyubiquitins stretched by various linkages. The terminal-to-terminal stretching of polyubiquitin results in peak forces similar to those measured for titin-based polyproteins and of a magnitude that matches measurements. Consistent with the experimental measurements, the simulated peak forces depend on the pulling speed logarithmically when thermal fluctuations are explicitly introduced. These results validate the application of topology-based models in the study of the mechanical stretching of proteins.
Uniform and high-quality submicrometer tubes of GaS layered crystals
Authors: Hu J. Q. , Bando Y. , Zhan J. H. , Liu Z. W. , Golberg D.
Published: November 2005

GaS, group III–VI semiconductor compound, is known to possess a layered structure. In this letter, uniform and high-quality GaS submicrometer tubes have been synthesized via a simple high-temperature thermal reaction route. Each GaS tube is uniform in size, and has length up to tens of microns and outer diameter of ∼200–900nm; some of the tubes are partially filled with liquid metallic Ga “rods.” Photoluminescence spectrum reveals that the GaS tubes have two strong emission bands centered at ∼585 and ∼615nm. Possible reaction processes and a rolling-up growth mechanism of as-grown GaS tubes were briefly discussed.
Metallic tip probe providing high intensity and small spot size with a small background light in near-field optics
Authors: Tanaka Kazuo , Tanaka Masahiro , Sugiyama Tatsuhiko
Published: November 2005

A metallic tip probe that gives high optical intensity and small spot size with a small background light is proposed and simulated. The proposed tip probe provides advantages of both the aperture probe and the apertureless probe currently used in the scanning near-field optical microscope. The tip probe is illuminated by surface plasmon polaritons transmitted through the I-shaped aperture in a pyramidal structure on a thick metallic screen. Scattering of optical waves by this structure is solved numerically using a volume integral equation by generalized conjugate residual iteration and fast Fourier transformation. The proposed tip probe is shown to simultaneously provide both high near-field intensity and small spot size with a small background light.
Improvement of the current-voltage characteristics of a tunneling dielectric by adopting a Si3N4∕SiO2∕Si3N4 multilayer for flash memory application
Authors: Hong Sug Hun , Jang Jae Hyuck , Park Tae Joo , Jeong Doo Seok , Kim Miyoung , Hwang Cheol Seong , Won Jeong Yeon
Published: November 2005

Superior characteristics of an atomic-layer-deposited (ALD) Si3N4 layer and Si3N4∕SiO2∕Si3N4 stacked layers as a tunneling gate dielectric for nonvolatile flash memory application are reported. Compared to a single layer of SiO2 electric field-sensitive characteristics were obtained by barrier profile engineering with a stacked layer; a lower leakage current at a low field and a higher leakage current at a high field. The stacked dielectric layer showed Fowler–Nordheim tunneling. However, the interfacial potential barrier profile was somewhat smoothed by chemical interaction between the individual layers. The interfacial trap density of this dielectric with an ALD Si3N4 bottom layer was as low as 4×10−10∕cm2eV near the mid-gap energy state, but the reoxidation process degraded the interface quality. The degradation mechanism was studied.
Rectification and intrinsic photocurrent of GaAs∕Si photodiodes formed with pulsed-laser deposition at 1064nm
Authors: Ullrich B. , Erlacher A.
Published: November 2005

With a rate of 1nmperminute, thin-film p-GaAs has been deposited on n-Si with nanosecond laser pulses at 1064nm. The samples revealed rectification with an uncommon power dependence on the forward bias. Furthermore, we noticed that the intrinsic photocurrent spectra sensitively depend on the deposition time. Increasing this duration from one to three hours shifts the maximum of the spectral device response from GaAs to Si. The result stresses the flexibility of pulsed-laser deposition to alter device properties in extremely simple ways.
Effective channel length measurement of metal-oxide-semiconductor transistors with pocket implant using the subthreshold current-voltage characteristics based on remote Coulomb scattering
Authors: Eng C. W. , Lau W. S. , Vigar D. , Tan S. S. , Chan L.
Published: November 2005

For deep submicron metal-oxide-semiconductor (MOS) transistors with pocket implant, the electron mobility of the short channel transistor is always smaller than that of the long channel transistor in the above-threshold regime, resulting in serious error in effective channel length (Leff) measurement based on the assumption that the mobility is independent of gate length. Our theory predicts that when the gate oxide is very thin the electron mobility is approximately equal for short and long channel MOS transistors in the subthreshold regime. Thus it is possible to perform Leff measurement in the subthreshold region of MOS transistors with ultrathin gate oxide.
Ultra-high-Q microcavity operation in H2O and D2O
Authors: Armani A. M. , Armani D. K. , Min B. , Vahala K. J. , Spillane S. M.
Published: November 2005

Optical microcavities provide a possible method for boosting the detection sensitivity of biomolecules. Silica-based microcavities are important because they are readily functionalized, which enables unlabeled detection. While silica resonators have been characterized in air, nearly all molecular detections are performed in solution. Therefore, it is important to determine their performance limits in an aqueous environment. In this letter, planar microtoroid resonators are used to measure the relationship between quality factor and toroid diameter at wavelengths ranging from visible to near-IR in both H2O and D2O, and results are then compared to predictions of a numerical model. Quality factors (Q) in excess of 108, a factor of 100 higher than previous measurements in an aqueous environment, are observed in both H2O and D2O.
Enhancement of solar cell performance by employing planar spectral converters
Authors: van Sark W. G. J. H. M.
Published: November 2005

The effect on solar cell performance of planar converters containing quantum dots (QDs) as wavelength-shifting entities on top of multicrystalline silicon cells was investigated by means of model studies with varying incident spectra. These included global, direct, and diffuse spectra with Air Mass (AM) values ranging from 1 to 10. In case of AM1.5, a planar converter with QDs emitting at 603nm yields a short-circuit current increase of 6.3%, 9.6%, and 28.6% for direct, global, and diffuse irradiation, respectively, as a result of the larger blue/green content of diffuse spectra with respect to direct and global ones. For other AM values, similar results are calculated, with a lower increase toward high AM values.
Overcoming entropic barrier with coupled sampling at dual resolutions
Authors: Lwin Thur Zar , Luo Ray
Published: November 2005

An enhanced sampling method is proposed for ab initio protein folding simulations. The new method couples a high-resolution model for accuracy and a low-resolution model for efficiency. It aims to overcome the entropic barrier found in the exponentially large protein conformational space when a high-resolution model, such as an all-atom molecular mechanics force field, is used. The proposed method is designed to satisfy the detailed balance condition so that the Boltzmann distribution can be generated in all sampling trajectories in both high and low resolutions. The method was tested on model analytical energy functions and ab initio folding simulations of a β-hairpin peptide. It was found to be more efficient than replica-exchange method that is used as its building block. Analysis with the analytical energy functions shows that the number of energy calculations required to find global minima and to converge mean potential energies is much fewer with the new method. Ergodic measure shows that the new method explores the conformational space more rapidly. We also studied imperfect low-resolution energy models and found that the introduction of errors in low-resolution models does decrease its sampling efficiency. However, a reasonable increase in efficiency is still observed when the global minima of the low-resolution models are in the vicinity of the global minimum basin of the high-resolution model. Finally, our ab initio folding simulation of the tested peptide shows that the new method is able to fold the peptide in a very short simulation time. The structural distribution generated by the new method at the equilibrium portion of the trajectory resembles that in the equilibrium simulation starting from the crystal structure.
Subregional slicing method to increase three-dimensional nanofabrication efficiency in two-photon polymerization
Authors: Park Sang Hu , Lee Sang Ho , Yang Dong-Yol , Kong Hong Jin , Lee Kwang-Sup
Published: November 2005

A subregional slicing method (SSM) is proposed to increase the nanofabrication efficiency of a nanostereolithography (NSL) process based on two-photon polymerization (TPP). The NSL process can be used to fabricate three-dimensional (3D) microstructures via the accumulation of layers of uniform thickness; hence, the precision of the final 3D microstructure depends on the layer thickness. The use of a uniform layer thickness means that, to fabricate a precise microstructure, a large number of thin slices is inevitably required, leading to long processing times. In the SSM proposed here, however, the 3D microstructure is divided into several subregions on the basis of the geometric slope, and then each of these subregions is uniformly sliced with a layer thickness determined by the geometric slope characteristics of each subregion. Subregions with gentle slopes are sliced with thin layer thicknesses, whereas subregions with steep slopes are sliced with thick layer thicknesses. Here, we describe the procedure of the SSM based on TPP, and discuss the fabrication efficiency of the method through the fabrication of a 3D microstructure.
Effects of microbial loading and sporulation temperature on atmospheric plasma inactivation of Bacillus subtilis spores
Authors: Deng X. T. , Shi J. J. , Shama G. , Kong M. G.
Published: November 2005

Current inactivation studies of Bacillus subtilis spores using atmospheric-pressure glow discharges (APGD) do not consider two important factors, namely microbial loading at the surface of a substrate and sporulation temperature. Yet these are known to affect significantly microbial resistance to heat and hydrogen peroxide. This letter investigates effects of microbial loading and sporulation temperature on spore resistance to APGD. It is shown that microbial loading can lead to a stacking structure as a protective shield against APGD treatment and that high sporulation temperature increases spore resistance by altering core water content and cross-linked muramic acid content of B. subtilis spores.
Spin-preserving ultrafast carrier capture and relaxation in InGaAs quantum dots
Authors: Trumm S. , Wesseli M. , Krenner H. J. , Schuh D. , Bichler M. , Finley J. J. , Betz M.
Published: November 2005

Carrier capture into self-organized InGaAs∕GaAs quantum dots with an electronic level spacing close to optical phonon energies is studied in a two-color femtosecond transmission experiment. After resonant generation of carriers in the wetting layer, we analyze the population of both the band edge of the wetting layer and the excited states of the quantum dots. Most strikingly, the carrier capture time of 3 ps is found to be independent of the carrier density, providing that it remains small compared to the number of available electronic states in the quantum dots. Moreover, we find that the capture process is predominantly spin preserving in nature. These results suggest that phonon-mediated scattering governs the quantum dot filling.
Double-gate organic field-effect transistor
Authors: Morana M. , Bret G. , Brabec C.
Published: November 2005

We present a novel double-gate structure for polymeric field-effect transistors produced from a solution of [9,9]-dioctylfluorene-co-bithiophene copolymer (F8T2) as the p-type organic semiconductor. The double-gate geometry adapts to different bias configurations and shows improved performances and higher flexibility of operation with respect to single-gate devices. The device characteristics show an increased on/off ratio and demonstrate the possibility to control the threshold voltage as well as the off current. The maximum hole mobility of 8×10−2cm2∕Vs measured for the F8T2 layer, in combination with the features of the double-gate structure, suggest the possibility to produce optimized devices with very high performances.