bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of the Covid Pandemic on the Economic Vulnerability of Italian Society.
Authors:   University of Milano-Bicocca, Fattore Marco , Rimoldi Stefania M.L. ,   University of Milano-Bicocca
Published: January 2024

This paper provides some insights on the effects of the Covid pandemic, on the economic vulnerability of Italian society. Data come from the first 5 waves of a special social survey, held by Bank of Italy, to monitor the economic consequences of the Covid emergency. Economic vulnerability is assessed through a set of four ordinal variables, then condensed into a synthetic measure, by using tools from Partial Order Theory; social groups are identified based on profiling socio-economic variables. Results reveal the heavy economic impact of the pandemic and the risk of increased polarization of the Italian society.
Economic Insecurity and Health
Authors:   University of Luxembourg, D’Ambrosio Conchita , Clark Andrew E. ,   Paris School of Ecomonics-CNRS and University of Luxembourg
Published: January 2024

We here show that individual-level economic insecurity, based on the time profile of economic resources, is detrimental to both physical and mental health in long-run Australian panel data. This relationship is found in panel data, comparing an individual’s change in economic security over time to the changes in her health. A heterogeneity analysis reveals that economic insecurity is particularly detrimental to the health of the most-deprived, those over the age of 30, and men rather than women.
Youths’ Employment Vulnerability amidst a Lingering Crisis: Evidence from the Middle East
Authors:   Santa Clara University, Alazzawi Shireen , Hlasny Vladimir ,   Ecomonic affairs officer UN ESCWA
Published: January 2024

This study estimates the impacts of the lingering COVID crisis on workers’ outcomes in four Middle East and North African (MENA) countries –Egypt, Jordan, Morocco and Tunisia– using panel microdata from ERF COVID-19 MENA Monitors (February ‘20-September ‘21). Workers’ employment statuses were assessed using transition matrices and multinomial logistic models with quasi fixed effects. We confirm that strict COVID regulatory regimes have negative effects on employment outcomes of most groups of workers, but the effects cannot be consistently ranked between age cohorts and genders across the four countries. In 2021, men’s employment prospects gradually improved, but women remained largely excluded from work opportunities. Youths trailed non-youths throughout the pandemic, perpetuating existing inequalities along sex and age dimensions, but also vis-à-vis workers’ socioeconomic status represented by their education and employment type.
Exploring the Role of Robotic Automation in Climate Vulnerability Mitigation: Towards Sustainable Horticulture
Authors: Sharma Anwesha , Kumar Shivam , Singh Anand , Kumar Sunil , Saurabh  , Yadav Harish Chandra , Hazarika Sanjay , Hasan Rokibul
Published: January 2024

This paper investigates the potential of robotic automation in addressing climate vulnerability within the context of horticulture. As climate change intensifies, horticultural systems face increasing challenges, impacting crop yields, resource management, and environmental sustainability. The paper delves into the concept of leveraging robotic automation as an innovative solution to mitigate climate vulnerabilities in horticulture. It explores the benefits and challenges associated with the integration of robotic technologies in agricultural practices. By examining case studies and emerging trends, the paper highlights how robotic automation can contribute to sustainable horticulture practices. Ultimately, the study emphasizes the importance of aligning technological advancements with environmental resilience, paving the way for a more resilient and sustainable future for horticulture.
Revolutionizing Guava Food Processing: A Fresh Perspective
Authors: Vikram Balaji , Gautam Dharmendra Kumar , Tondihal Manjunath Sharanappa , Chaturvedi Shweta , Verma Sameer , Yadav Harish Chandra , Sonkar Abhishek , Nayak Tekchand
Published: January 2024

This study investigates the contemporary shift in guava processing paradigms, capitalizing on technological advancements, sustainable practices and value addition. Exploring novel methods, the research aims to revolutionize traditional guava processing by enhancing efficiency, quality and sustainability. Through the integration of cutting-edge techniques, the article envisions a transformative era in guava processing, fostering advancements in production and product utilization. This innovative approach responds to consumer demands for healthier, sustainable choices, promising a future in guava processing that aligns with dynamic global culinary preferences.
Glyphosate‐based pesticides affect cell cycle regulation
Authors: Marc Julie , Mulner‐Lorillon Odile , Bellé Robert
Published: February 2004

Summry— Cell‐cycle dysregulation is a hallmark of tumor cells and human cancers. Failure in the cell‐cycle checkpoints leads to genomic instability and subsequent development of cancers from the initial affected cell. A worldwide used product Roundup 3plus, based on glyphosate as the active herbicide, was suggested to be of human health concern since it induced cell cycle dysfunction as judged from analysis of the first cell division of sea urchin embryos, a recognized model for cell cycle studies.

Several glyphosate‐based pesticides from different manufacturers were assayed in comparison with Roundup 3plus for their ability to interfere with the cell cycle regulation. All the tested products, Amega, Cargly, Cosmic, and Roundup Biovert induced cell cycle dysfunction. The threshold concentration for induction of cell cycle dysfunction was evaluated for each product and suggests high risk by inhalation for people in the vicinity of the pesticide handling sprayed at 500 to 4000 times higher dose than the cell‐cycle adverse concentration.
More than G1 or G2 arrest: Useful starfish oocyte system for investigating skillful MAP kinase
Authors: Kishimoto Takeo
Published: February 2004

Summry— During the meiotic cycles in starfish oocytes, MAP kinase (MAPK) is involved in the meta‐I arrest, the meiosis I to II transition, and the arrest at pronucleus stage (G1 and/or G2 phase). The eventual fate, either development or death, of mature eggs is also under the control of MAPK. Starfish oocytes are thus a useful model system to study multiple functions of skillful MAPK.
Crustal fabric in the Tibetan Plateau based on waveform inversions for seismic anisotropy parameters
Authors: Sherrington Heather Folsom , Zandt George , Frederiksen Andrew
Published: February 2004

The Tibetan Plateau has the thickest continental crust on Earth, and fabrics within the crust that are anisotropic to seismic waves may provide clues to how it reached such extreme proportions and how it is currently deforming. Waveform modeling using a global minimization inversion technique applied to receiver functions computed from 11 stations spanning the north‐south length of the eastern plateau has yielded a suite of crustal models that include anisotropy. These models suggest that the Tibetan crust contains 4–14% anisotropy at different depths that is likely a result of both fossil fabrics and more recent deformation. All models contain anisotropy in the surface layer, and for most stations the alignment of the slow symmetry axis suggests a relationship with crustal fabrics associated with E‐W trending thrust faults or sutures. Middle to lower crustal anisotropy is present at most stations with a fast axis trending N‐S to NW‐SE in the south, nearly E‐W in the central plateau, and N‐S to NE‐SW in the northern plateau. This pattern appears consistent with recent ductile deformation due to both topographically induced flow and to boundary forces from subducting lithosphere at the northern and southern margins of the plateau. The orientations of crustal anisotropy determined for most stations in this study are significantly different from shear wave splitting fast polarization directions, implying distinct deformation in the crust and mantle.
Development of a physics‐based reduced state Kalman filter for the ionosphere
Authors: Scherliess L. , Schunk R. W. , Sojka J. J. , Thompson D. C.
Published: February 2004

A physics‐based data assimilation model of the ionosphere is under development as the central part of a Department of Defense/Multidisciplinary University Research Initiative (MURI)‐funded program called Global Assimilation of Ionospheric Measurements (GAIM). With the significant increase in the number of ionospheric observations that will become available over the next decade, this model will provide a powerful tool toward an improved specification and forecasting of the global ionosphere, with an unprecedented accuracy and reliability. The goal of this effort will be specifications and forecasts on spatial grids that can be global, regional, or local (25 km × 25 km). The specification/forecast will be in the form of three‐dimensional electron density distributions from 90 km to geosynchronous altitudes (35,000 km). The main data assimilation in GAIM will be performed by a Kalman filter. In this paper we present a practical method for the implementation of a Kalman filter using a new physics‐based ionosphere/plasmasphere model (IPM). This model currently includes 5 ion species (O2+, N2+, NO+, O+, and H+) and covers the low and middle latitudes from 90 km to about 20,000 km altitude. A Kalman filter based on approximations of the state error covariance matrix is developed, employing a reduction of the model dimension and a linearization of the physical model. These approximations lead to a dramatic reduction in the computational requirements. To develop and evaluate the performance of the algorithm, we have used an Observation System Simulation Experiment. In this paper, we will initially present the physics‐based IPM used in GAIM and demonstrate its use in the reduced state Kalman filter. Initial results of the filter in the South American sector using synthetic measurements are very encouraging and demonstrate the proper performance of the technique.
Data assimilation of ground GPS total electron content into a physics‐based ionospheric model by use of the Kalman filter
Authors: Hajj G. A. , Wilson B. D. , Wang C. , Pi X. , Rosen I. G.
Published: February 2004

A three‐dimensional (3‐D) Global Assimilative Ionospheric Model (GAIM) is currently being developed by a joint University of Southern California and Jet Propulsion Laboratory (JPL) team. To estimate the electron density on a global grid, GAIM uses a first‐principles ionospheric physics model and the Kalman filter as one of its possible estimation techniques. Because of the large dimension of the state (i.e., electron density on a global 3‐D grid), implementation of a full Kalman filter is not computationally feasible. Of the possible suboptimal implementations of the Kalman filter, we have chosen a band‐limited Kalman filter where a full time propagation of the state error covariance is performed, but it is always kept sparse and banded. The effectiveness of ground GPS data for specifying the ionosphere is assessed by assimilating slant total electron content (TEC) data from 98 sites into the GAIM Kalman filter and validating the electron density field against independent measurements. A series of GAIM analyses are presented and validated by comparisons to JPL's global ionospheric maps (GIM) of vertical TEC (VTEC) and measurements from TOPEX. A statistical evaluation of GAIM and GIM against TOPEX VTEC indicates that GAIM accuracy is comparable or superior to GIM.
Cathodoluminescence characteristics of Archean volcanogenic massive sulfide related quartz: Noranda, Ben Nevis and Matagami districts, Abitibi Subprovince, Canada
Authors: Ioannou S. E. , Götze J. , Weiershäuser L. , Zubowski S. M. , Spooner E. T. C.
Published: February 2004

The cathodoluminescence (CL) of quartz from ore, stockwork, veins, and interstitial fillings between lava pillows from the ∼2.7 Ga Noranda, Ben Nevis and Matagami volcanogenic massive sulfide (VMS) districts, Abitibi greenstone belt, has been investigated using the “hot cathode” technique (HC1‐LM system) to assess the potential of these various sample types to host primary, seafloor VMS‐related fluids trapped as inclusions in minerals with primary depositional morphologies. The CL responses indicate that the various quartz types are of hydrothermal origin, and are therefore a potential host for primary hydrothermal fluid inclusions. Most notable is a transient (t < 120 s) blue CL, characteristic of hydrothermal quartz, observed in most samples. CL characteristics are similar over ∼250 km indicating coherent, nonrandom behavior. Furthermore, in ore and stockwork material from the Matagami and Noranda districts respectively, CL reveals primary concentric growth zoned quartz that predates pulses of sulfide deposition–clear evidence that the quartz is undeformed and directly related to VMS mineralization. These growth zones are not apparent in transmitted light. In addition, ore and stockwork quartz commonly show a very unstable (t < 30 s) yellow CL coincident with microfractures and grain boundaries, defining areas affected by secondary hydrothermal activity. In ore from Matagami, local zones of nontransient brown CL may reflect strain zones associated with the deformation and recrystallization of the massive sulfide mound and indicate that such modifications can be recognized and are minor in the investigated cases. CL clearly reveals pseudo‐hexagonal, apparently zoned structures in sulfide‐mineralized breccia pipe quartz from the Ben Nevis area. These structures and their host quartz, characterized by a very unstable (t < 20 s) bright yellow CL, are interpreted as recrystallized quartz that has undergone rapid growth from a strongly supersaturated solution and noncrystalline precursor. The CL also clearly reveals colloform/crustiform textures indicative of open‐space filling; these textures are not visible optically.
Satellite monitoring of vegetation dynamics: Sensitivity enhancement by the wide dynamic range vegetation index
Authors: Viña Andrés , Henebry Geoffrey M. , Gitelson Anatoly A.
Published: February 2004

Synoptic monitoring of vegetation dynamics relies on satellite observations of the distinctive spectral contrast between red and near infrared reflectance that photosynthetically active green vegetation exhibits. It has long been recognized that the Normalized Difference Vegetation Index (NDVI) suffers a rapid decrease of sensitivity at moderate‐to‐high densities of photosynthetic green biomass. This decrease can conceal detection of vegetation change in croplands, woodlands, and productive grasslands. We applied a recent, straightforward modification of the NDVI, the Wide Dynamic Range Vegetation Index (WDRVI), to a standard AVHRR dataset to assess its sensitivity to variability within ecoregions and across years, relative to NDVI. In productive ecoregions, the sensitivity increased within a single year by up to 47% and the sensitivity to interannual variability increased by up to 100%. The WDRVI exhibited no increase in sensitivity in ecoregions with sparse vegetation. These findings have significant implications for diverse applications of vegetation monitoring products.
Validity of the fluid description of critical β and Alfvén time scale of ballooning instability onset in the near‐Earth collisionless high‐β plasma
Authors: Miura Akira
Published: February 2004

For a realistic, highly stretched, two‐dimensional tail configuration, in which the pressure gradient force is balanced with the curved field line tension force at the equator, the growth rates and the real frequencies of the ideal magnetohydrodynamic (MHD) and two component fluid (nonideal MHD) ballooning modes, in which the phrase “two component fluid” means that the Hall and the electron pressure gradient terms are included in the generalized Ohm's law, the ion bounce frequency ωbi, the ion magnetic drift frequency ωdi, the ion diamagnetic drift frequency ω*i, and the ion cyclotron frequency ωci are calculated numerically at the equator as a function of X from the near‐Earth tail (X = −15 RE) to the midtail (X = −30 RE). Contrary to the well‐known dipole field case, in which the bounce frequency decreases with increasing ∣X∣, the ion bounce frequency increases with ∣X∣ for the tail configuration. The ion magnetic drift frequency dominated by the curvature drift frequency also increases with increasing ∣X∣. The exact growth rates of the ideal and nonideal ballooning modes, γe and γne, which are nearly equal, are given by 1.22VA/Rc, where VA is the Alfvén velocity and Rc is the field line curvature radius at the equator, and satisfy ωbi, ωdi, ω*i < γe < ωci on average in the near‐Earth tail at X ∼ −15 RE. Also, the ion motion remains adiabatic in the near‐Earth tail at X ∼ −15 RE. Therefore it is a posteriori verified that the fluid or MHD description of the linear stability of the ballooning instability is valid, and the critical β and the Alfvén time scale τA ∼ Rc/VA of the ballooning instability onset obtained by the fluid theory are validated in the near‐Earth tail as close as 15 RE from the Earth. Despite the plasma being collisionless and high‐β in the near‐Earth tail, the subtle collisionless kinetic effects due to the field line curvature in high‐β collisionless plasma are not significant enough to invalidate the fluid description in the near‐Earth tail. The Alfvén time scale of an e‐folding growth of the Alfvén wave trapped within Rc in the equatorial region is of the order of a few tens of seconds or less in the near‐Earth tail. It is faster than the bounce time of the bulk of ions and can explain the observed rapid time scale of a substorm onset. There is excellent agreement between the critical β and the Alfvén time scale obtained analytically for the two component fluid plasma and those obtained by a three‐dimensional particle simulation.
Magnetospheric electric fields and plasma sheet injection to low L‐shells during the 4–5 June 1991 magnetic storm: Comparison between the Rice Convection Model and observations
Authors: Garner T. W. , Wolf R. A. , Spiro R. W. , Burke W. J. , Fejer B. G. , Sazykin S. , Roeder J. L. , Hairston M. R.
Published: February 2004

The major magnetic storm of 4–5 June 1991 was well observed with the Combined Release and Radiation Experiment (CRRES) satellite in the duskside inner magnetosphere and with three Defense Meteorological Satellite Program (DMSP) spacecraft in the polar ionosphere. These observations are compared to results from the Rice Convection Model (RCM), which calculates the inner magnetospheric electric field and particle distribution self‐consistently. This case study, which uses the most complete RCM runs to date, demonstrates two significant features of magnetospheric storms, the development of subauroral polarization streams (SAPS) and plasma‐sheet particle injection deep into the inner magnetosphere. In particular, the RCM predicts the electric field peak near L = 4 that is observed by the CRRES satellite during the second injection. The RCM calculations and DMSP data both show SAPS events with similar general characteristics, though there is no detailed point‐by‐point agreement. In the simulation, SAPS are generated by the deep penetration of plasma sheet protons to L < 4 and Earthward of the plasma sheet electrons. Similarly, the vast majority of the ions that make up the storm‐time ring current came from the plasma sheet; most of the particles that made up the prestorm quiet‐time ring current escaped through the dayside magnetopause during ring current injection. The RCM demonstrates the capability of plasma sheet ions to reach all ring current orbits and predicts the location of the injected particles (both ions and electrons) reasonably well. However, it overpredicts the ion flux in the inner magnetosphere.
Thin current sheets and loss of equilibrium: Three‐dimensional theory and simulations
Authors: Birn J. , Dorelli J. C. , Hesse M. , Schindler K.
Published: February 2004

Using quasi‐static equilibrium theory and three‐dimensional MHD simulations, we confirm earlier two‐dimensional results that finite boundary deformations of magnetotail equilibria can lead to large local current density enhancements, that is, the formation of thin current sheets. Equilibrium configurations that satisfy flux, entropy, and topology conservation cease to exist when the boundary deformations exceed critical limits. This provides a strong argument for onset of instability or the loss of equilibrium, regardless of the dissipation mechanism. Catastrophe points can be reached for relatively modest perturbations of the boundary. The most important internal property that influences the critical limit is the variation of the lobe magnetic field strength with distance from the Earth, related to the overall tail flaring. Stronger flaring, corresponding to a more rapid decrease of the lobe field with distance downtail, tends to stabilize the tail. That means such configurations require stronger perturbations to reach the critical limit or show less significant thinning and current density intensification for a given perturbation. Due to the nonlinearity of the tail response to the perturbations, the current intensification tends to be more localized than the perturbation.
Creep, dike intrusion, and magma chamber deflation model for the 2000 Miyake eruption and the Izu islands earthquakes
Authors: Ozawa S. , Miyazaki S. , Nishimura T. , Murakami M. , Kaidzu M. , Imakiire T. , Ji X.
Published: February 2004

Analysis of Global Positioning System data shows shrinkage of Miyake Island and the widening between Nijima and Kozu Islands during the period of the Miyake island volcanic activity and the ensuing Izu islands earthquakes in 2000. The estimated time evolution of a model consisting of a dike, creeping faults, and a Mogi source suggests that a crack opening on Miyake Island occurred immediately after the start of the seismic activities on 26 June and ended within several days at the west coast of Miyake Island. After the seabed eruption on 27 June, magma migrated from Miyake Island to Kozu and Nijima Islands within several days. The estimated volume of intruded magma totals around 1.2 × 109 m3. Associated with the magma intrusion between Miyake and Kozu Islands, left‐lateral and right‐lateral creep motions occurred in regions off the west coast of Miyake Island and near Kozu Island. The accumulated moment energy is equivalent to an earthquake of Mw 6.6 and 6.6 for right‐lateral and left‐lateral creeping faults, respectively. The estimated magma chamber continued deflation beneath the southwestern part of Miyake Island from 26 June, totaling around 0.12 × 109 m3 in volume change, in addition to the collapse volume of 0.6 × 109 m3 at the summit of Mount Oyama on Miyake Island. The volume change on Miyake Island can be compensated by the migrated magma toward Kozu Island from the deflation source beneath Miyake Island. The deflation speed of the magma chamber beneath Miyake Island decreased and increased before and after the eruption of 14–15 July and 18 August, suggesting a change in balance of mass influx and draining out rate of the magma chamber.
Interannual long equatorial waves in the tropical Atlantic from a high‐resolution ocean general circulation model experiment in 1981–2000
Authors: Illig S. , Dewitte B. , Ayoub N. , du Penhoat Y. , Reverdin G. , De Mey P. , Bonjean F. , Lagerloef G. S. E.
Published: February 2004

We investigate the tropical Atlantic vertical structure variability (1981–2000) based on the CLIPPER ocean general circulation model (OGCM). We aim at determining to what extent the observed interannual variability can be explained by the low‐frequency wave dynamics. The linear vertical modes of the OGCM climatological stratification are estimated along the equator. The baroclinic mode contributions to surface zonal current and sea level anomalies are calculated and analyzed at interannual timescales. The second baroclinic mode is the most energetic. The first (third) mode exhibits a variability peak in the west (east). The summed‐up contribution of the high‐order baroclinic modes (4–6) is as energetic as the gravest modes and is largest in the east. Wave components are then derived by projection onto the associated meridional structures. The effect of longitudinal boundaries near the equator is taken into consideration. Equatorial Kelvin and Rossby waves propagations, with phases speed close to the theory, are identified for the first three baroclinic modes. The comparison with a multimode linear simulation corroborates the propagating properties of the OGCM waves coefficients. An estimation of the meridional boundary reflection efficiency indicates that wave reflections take place at both boundaries. A 65% reflection efficiency is found at the eastern boundary. Our study suggests that low‐frequency wave dynamics is to a large extent at work in the tropical Atlantic. On the basis of what is known on the Pacific El Niño‐Southern Oscillation mode this may provide a guidance for investigating ocean‐atmosphere mechanisms that can lead to the Atlantic zonal equatorial mode.
Meridional transport of North Pacific Intermediate Water across 37°N based on an objective analysis of lowered acoustic Doppler current profiler data
Authors: Yoshinari Hiroshi , Yasuda Ichiro , Ikeda Motoyoshi
Published: February 2004

Meridional transport and origin of North Pacific Intermediate Water (NPIW) in the Kuroshio‐Oyashio interfrontal zone (K/O zone) are examined using hydrographic and lowered acoustic Doppler current profiler (LADCP) velocity data along 37°N obtained in July 1998. An optimal interpolation method was applied to objectively derive transports and their spatial‐interpolation errors. A statistically significant northward transport of 12.0 ± 4.6 Sv was observed in the density interval 26.6–27.5σθ between the coast (141°E) and the Shatsky Rise (157°E). In the upper part of NPIW (26.6–27.0σθ), the total transport was 4.1 ± 1.2 Sv, of which the Kuroshio component was 3.0 ± 0.7 Sv and Oyashio was 1.1 ± 0.5 Sv. In the lower NPIW (27.0–27.5σθ), the total transport was 7.9 ± 3.4 Sv, comprising 4.7 ± 1.9 Sv of Kuroshio water and 3.2 ± 1.5 Sv of Oyashio water. A southward transport of 4.4 ± 3.6 Sv was observed between the Shatsky Rise and 179.5°E in the density interval 26.6–27.5σθ. In the region west of the Shatsky Rise, the Oyashio mixing ratio derived from temperature and salinity in the K/O zone is larger than the ratio of Oyashio to Kuroshio transport, implying southward transport of 1 Sv of Oyashio water across the Oyashio Front in the upper NPIW. Mixing and transport ratios are almost the same in the lower NPIW, suggesting that this region is maintained only by the northward transport of NPIW formed near the Kuroshio Extension.
Analysis of flow at the gate of Taiwan Strait
Authors: Wang Yu‐Huai , Chiao Ling‐Yun , Lwiza Kamazima M. M. , Wang Dong‐Ping
Published: February 2004

A field survey with ship‐borne acoustic Doppler current profiler was carried out across the Penghu Channel, the gate of Taiwan Strait, from 17 to 20 of May 1999. A new method of least‐squares interpolation is used to separate the mean flow from tidal currents. The technique uses Gaussian interpolation functions with local support which also take into consideration the anisotropic nature of the flow structure. Optimal solution is obtained by determining the tradeoff between the misfit and the model order. The analysis indicates that the currents in the Penghu Channel are essentially barotropic and characterized by strong semidiurnal tides and mean flow. The along‐channel averaged tidal velocity amplitudes are 1.2 m s−1 and 0.32 m s−1 for semidiurnal and diurnal tides, respectively. The mean current is uniform with an average northward velocity of 0.73 m s−1. The total transport is about 1.6 Sv, which represents a significant mass and material flux into the East China Sea.
Constraining climatic controls on hillslope dynamics using a coupled model for the transport of soil and tracers: Application to loess‐mantled hillslopes, South Island, New Zealand
Authors: Roering Joshua J. , Almond Peter , Tonkin Philip , McKean James
Published: February 2004

Landscapes reflect a legacy of tectonic and climatic forcing as modulated by surface processes. Because the morphologic characteristics of landscapes often do not allow us to uniquely define the relative roles of tectonic deformation and climate, additional constraints are required to interpret and predict landscape dynamics. Here we describe a coupled model for the transport of soil and tracer particles at the hillslope scale. To illustrate the utility of this methodology, we modeled the evolution of two synthetic hillslopes with identical initial and boundary conditions but different histories of climate‐induced changes in the efficiency of soil transport. While one hillslope experienced an initial phase of rapid transport followed by a period of retarded transport, the other hillslope experienced the opposite sequence. Both model hillslopes contain a subsurface layer of tracer particles that becomes exhumed and incorporated into the soil due to transport and mixing processes. Whereas the morphology of the two model hillslopes cannot be easily distinguished at the simulation conclusion, the spatial distribution of tracer particles along the slope is distinctive for the two cases. We applied the coupled model to our study site along the Charwell River, South Island, New Zealand, where tephra deposits within loess‐dominated soils have been exhumed and incorporated into an upper layer of bioturbated and mobile soil. We reconstructed the late Pleistocene hillslope geometry using soil stratigraphic data gathered along the study transect. Because bioturbation appears to be the predominant transport mechanism, the efficiency of soil transport likely varies with time, reflecting the influence of climate‐related changes in the dominant floral or faunal community. The modeled evolution of hillslope form and tephra concentration along the study transect is consistent with observations obtained from topographic surveys and laboratory analysis of tephra concentrations in continuous‐core soil samples. Low transport rates are apparently associated with grass/shrub‐dominated slopes during the late Pleistocene, whereas forest colonization during the Holocene increased flux rates, transforming flat, locally incised slopes into broadly convex ones. Our results attest to the utility of coupled models for tasks such as deciphering landscape history and predicting the downslope flux of soil organic carbon.
Radar signal simulation: Surface modeling with the Facet Method
Authors: Nouvel J.‐F. , Herique A. , Kofman W. , Safaeinili A.
Published: February 2004

A major finding in exploration of Mars is the indication that a large quantity of water has been present on Mars. To discover the distribution of this quantity of water, the Mars Express spacecraft is carrying a spaceborne radar sounder, called Mars Advance Radar for Subsurface and Ionospheric Sounding (MARSIS), in order to map Mars subsurface dielectric characteristics. The returned radar echoes from Mars will contain both surface and subsurface reflection components, but the part of the signal we are interested in is the reflected signal from subsurface layers. To retrieve these weak deep echoes from the radar signal, a signal processing algorithm needs to be developed. In this paper, we present a computationally efficient radar signal simulation based on the use of the Facet Method as a surface modeling scheme. This simulator will be used to validate the MARSIS ground processing software and to support the interpretation of MARSIS data. The first step in the simulation algorithm definition is to model the Mars surface. Many surface modeling methods have been developed and can be found in the literature, but considering the fact that Mars surface is very smooth, the modeling algorithm we have developed uses the Facet Method. In this paper, we show that the Facet Method is an efficient scheme for modeling a relatively smooth surface, such as the Mars' surface. The instrument simulation we define makes strict reference to the MARSIS radar parameters; however, it may be used to model any radar sounder.
The São Luís 30 MHz coherent scatter ionospheric radar: System description and initial results
Authors: de Paula Eurico R. , Hysell David L.
Published: February 2004

A new 30 MHz coherent scatter ionospheric radar has been operating at the equatorial station at São Luís (2.33°S, 44°W, dip latitude 1.3°S), Brazil, since December 2000. This VHF radar has a peak power of only 8 kW but uses long coded pulses and a high PRF with coherent integration to achieve good sensitivity. Two side‐by‐side square antenna arrays composed of 16 5‐element Yagi antennas directed vertically are used for transmission and reception. This radar measures the backscattered signals from E and F region ionospheric irregularities. In the standard operational mode, the irregularity intensity, as well as the vertical and zonal velocities using Doppler analysis and interferometry, respectively, are determined. We initially present a brief description of the radar system, signal characteristics and data processing, followed by some of the initial observations. Electrojet echoes ranged from about 94 to 108 km in altitude with the strongest echoes coming from about 104 km and with an uplift to about 110 km occurring in the late afternoon. Echoes from the valley region (150 km echoes) were strong, quasi‐periodic with periods of about 10 to 15 minutes, and had the necklace shape observed at others sites. F region bottom‐type, bottomside, and topside (plumes) spread F layers were observed at night. The large‐scale topside F region plumes, moving eastward and upward, reached altitudes of about 1,400 km and were preceded by bottom‐type layers around 400 km altitude that were moving westward. The characteristics of the echoes were similar to those observed by the JULIA radar at Jicamaca, Peru. However, some differences in the behavior of the echoes between the two sites were noted.
Groundwater nitrate monitoring network optimization with missing data
Authors: Nunes L. M. , Paralta E. , Cunha M. C. , Ribeiro L.
Published: February 2004

A method for designing groundwater monitoring networks to define the extent of agricultural contamination is proposed. The method is particularly well suited to reducing existing networks where data are missing from time series records. A simulated annealing optimization algorithm is used to minimize the variance of the estimation error obtained by kriging in combinatorial problems, created by selecting an optimal subset of stations from the original set. Optimization is performed for several measuring times, obtaining an equal number of optimized small‐dimension networks; stations that repeat more often in these networks are selected to make part of the final network. A compliance groundwater nitrate monitoring network in the south of Portugal is used to illustrate the method. The original 89‐station network was converted into 16 stations. Results show that considerable reductions in operating costs (about 80%) are compatible with a cost‐effective network capable of detecting noncompliance with national and European norms.
Solubility of hydrogen and ferric iron in rutile and TiO2 (II): Implications for phase assemblages during ultrahigh‐pressure metamorphism and for the stability of silica polymorphs in the lower mantle
Authors: Bromiley Geoffrey , Hilaret Nadège , McCammon Catherine
Published: February 2004

The solubility of hydrogen in Fe2O3‐doped rutile and TiO2 (II) at 1100°C has been experimentally determined. H incorporation in rutile is coupled to substitution of Fe3+ onto the octahedral Ti4+ site. In contrast, TiO2 (II) contains no structurally‐incorporated hydrogen. The dominant Fe3+ incorporation mechanism in both phases is unrelated to H content, and involves substitution of Fe3+ onto octahedral Ti4+ sites, charge‐balanced by oxygen vacancies. Substitution of Fe2O3 into TiO2 (II) stabilizes the structure to much lower pressures than in the pure TiO2 system. Results indicate that Al‐bearing stishovite could act as an important carrier of water in subducting oceanic crust, but that formation of the post‐stishovite phase with the α‐PbO2 structure would represent a significant dehydration event at the base of the lower mantle.
Simulation of reflectometry density changes using a 2D full-wave code
Authors: da Silva F. , Manso M. , Silva A. ,   ASDEX Upgrade Team
Published: February 2004

Broadband reflectometry is used to obtain density profiles in fusion plasmas using waves reflected at different plasma layers. The reflected signal can be severely affected by plasma fluctuations and/or fast density changes. In order to understand the plasma response, a finite difference time domain two-dimensional full wave code was developed. The code was used to study typical situations of fusion plasmas where important profile movements occur: when a rotating magnetic island is present and during an ELM. The numerical results are in good agreement with experimental results obtained in ASDEX and ASDEX Upgrade in the situations above. Our study demonstrates that contributions from the plasma movements are important and should be taken into account to obtain accurate profile measurements.
Doppler reflectometry for the investigation of propagating density perturbations
Authors: Hirsch M. , Holzhauer E. , Baldzuhn J. , Kurzan B.
Published: February 2004

In a Doppler reflectometry experiment the line of sight is chosen to be nonperpendicular with respect to the reflecting layer. This type of diagnostic is able to probe density perturbations with the wave number in the reflecting layer selected by the tilt angle. The propagation velocity of the perturbations is calculated from the Doppler shift of the returning microwave signal whereas its intensity contains information about the perturbation amplitude. The diagnostic capability of Doppler reflectometry is demonstrated at the W7-AS stellarator using an antenna system with variable tilt angle. The measured values of the propagation velocity of density perturbations and its radial dependence are in good agreement with the E×B velocity of the plasma obtained from spectroscopy. Transient states can be followed with a temporal resolution less than 50 μs. Therefore Doppler reflectometry allows one to test the interdependence of sheared flow and turbulence on that timescale.
Measurement of cross-polarization scattering using ultrashort pulse microwaves
Authors: Kogi Y. , Mase A. , Hojo H. , Itakura A. , Ichimura M. , Tamano T.
Published: February 2004

A numerical simulation of cross-polarization scattering (CPS) was performed by using frequency dependent finite difference time domain [(FD)2TD] method. In the CPS process, an incident ordinary (extraordinary) wave is converted to an extraordinary (ordinary) wave by magnetic fluctuations in a plasma. It is confirmed in the simulation that an incident wave propagates in an anisotropic dispersive media properly. The relation between scattered electric field and magnetic fluctuations is also obtained.
New ECE diagnostics for the TEXTOR-94 tokamak
Authors: Udintsev V. S. , van de Pol M. J. , Donné A. J. H. , Oosterbeek J. W. , Krämer-Flecken A.
Published: February 2004

To aid the scientific research program on the Toroidal Experiment for Technology Oriented Research (TEXTOR)-94 tokamak, the existing electron cyclotron emission (ECE) diagnostics for the electron temperature studies are being extended with new systems that feature a good temporal and radial resolution. Using the possibility of obtaining the data on a fast time scale, ECE systems allow one to study fast phenomena like the dynamics of small-scale structures such as magnetic islands and transport barriers and microscopic temperature fluctuations throughout the plasma. The quantitative information about nonthermal electron populations can be obtained from the comparison of the second and third harmonic emission. A new 16-channel frequency tunable radiometer and a four-channel second harmonic system were recently installed at TEXTOR-94. The detailed description of the new TEXTOR-94 ECE systems and the recent results will be given and discussed in this article.
Application of millimeter-wave imaging system to LHD
Authors: Mase A. , Ohashi M. , Yamamoto A. , Negishi H. , Oyama N. , Nagayama Y. , Kawahata K. , Watabe K. , Mizuno K. , Matsuura H. , Uchida K. , Miura A.
Published: February 2004

Millimeter-wave imaging systems in the frequency range of 70–140 GHz have been developed for diagnostics of magnetically confined plasmas. The 70 GHz imaging system successfully measures time evolutions of both radial and axial profiles of line density and electron cyclotron emission (ECE) in a tandem mirror. The imaging system is being installed in Large Helical Device (LHD) at the National Institute for Fusion Science. In order to cover the frequency range of the second harmonic ECE on LHD, a new detector using monolithic microwave integrated circuit technology has been designed and fabricated. The detector consists of the integration of a receiving antenna, a down-converting mixer diode, and an intermediate frequency amplifier on a GaAs substrate chip. The heterodyne response up to 10 GHz was confirmed at 70–140 GHz. The optical system consisting of an ellipsoidal mirror and a flat mirror was designed by using a ray-tracing code and evaluated experimentally at 140 GHz.
Extreme broadband multichannel ECE radiometer with “zoom” device
Authors: Fuchs Ch. , Hartfuss H. J.
Published: February 2004

A new radiometer has been built up for the W7-AS stellarator which consists of a frontend with an extreme broadband mixer, two intermediate frequency (IF) parts with 16 channels each and a novel additional 16 filter section with variable IF. The system was designed with the future W7-X in mind. All settings can therefore be remotely changed. This “W7-X” system is integrated into the electron cyclotron emission (ECE) systems at W7-AS. EC radiation is collected using elliptical mirrors in Gaussian optics. W7-AS results will be shown. The “zoom” device is installed at DIII-D at the moment; first results are also shown.
The 14-channel grating polychromator for ECE measurements in LHD
Authors: Kawahata K. , deVries P. C. , Nagayama Y. , Inagaki S. , Tokuzawa T. , Tanaka K. , Sasao H.
Published: February 2004

A 14-channel grating polychromator for the purpose of measuring the electron cyclotron emission (ECE) spectrum has been developed and installed on the large helical device (LHD). The grating polychromator has a Czerny–Turner setup. The main advantage of the grating polychromator is that it has a broad spectral range. Hence, it can be utilized at different magnetic field strengths. Changing the angle or replacing the grating can do this. Gratings with a grid constant of d=2.3, 3, and 5 mm and a blaze angle of 20° can be applied and the scattered spectrum is directed to 14-liquid He cooled InSb detectors. Standard operation is performed with d=3 mm, frange=148–105 GHz. This is second harmonic ECE for B=2.75 T. Each channel has a spectral resolution of Δf (full width at half maximum)=2.6 GHz or f/Δf=60 at f=150 GHz. The properties of the instrument and first experimental results of LHD ECE will be described in this article.
Axial profile measurement of Alfvén ion cyclotron eigenmodes
Authors: Nakamura M. , Ichimura M. , Ohta Y. , Oikawa M. , Tanaka S. , Kogi Y. , Shima Y. , Saosaki S. , Kadoya K. , Kawabata T. , Kano H. , Itakura A. , Hojo H. , Mase A. , Yatsu K.
Published: February 2004

In the GAMMA10 tandem mirror, a strong ion cyclotron range of frequency heating is performed. As a result of the heating, the Alfvén ion cyclotron (AIC) modes are spontaneously excited due to the strong temperature anisotropy. The AIC modes in the GAMMA10 are excited as the axial eigenmodes and detected at the whole of the device. In the recent experiments, the clear standing wave structure is observed with the magnetic probe measurements. Characteristics of the AIC modes and the measurement of the axial profile are presented.
MAST magnetic diagnostics
Authors: Edlington T. , Martin R. , Pinfold T.
Published: February 2004

The mega-ampere spherical tokamak (MAST) experiment is a new, large, low aspect ratio device (R=0.7–0.8 m, a=0.5–0.65 m, maximum BT∼0.63 T at R=0.7 m) operating its first experimental physics campaign. Designed to study a wide variety of plasma shapes with up to 2 MA of plasma current with an aspect ratio down to 1.3, the poloidal field (PF) coils used for plasma formation, equilibrium and shaping are inside the main vacuum vessel. For plasma control and to investigate a wide range of plasma phenomena, an extensive set of magnetic diagnostics have been installed inside the vacuum vessel. More than 600 vacuum compatible, bakeable diagnostic coils are configured in a number of discrete arrays close to the plasma edge with about half the coils installed behind the graphite armour tiles covering the center column. The coil arrays measure the toroidal and poloidal variation in the equilibrium field and its high frequency fluctuating components. Internal coils also measure currents in the PF coils, plasma current, stored energy and induced currents in the mechanical support structures of the coils and graphite armour tiles. The latter measurements are particularly important when halo currents are induced following a plasma termination, for example, when the plasma becomes vertically unstable. The article describes the MAST magnetic diagnostic coil set and their calibration. The way in which coil signals are used to control the plasma equilibrium is described and data from the first MAST experimental campaign presented. These coil data are used as input to the code EFIT [L. Lao et al., Nucl. Fusion 25, 1611 (1985)], for measurement of halo currents in the vacuum vessel structure and for measurements of the structure of magnetic field fluctuations near the plasma edge.
Magnetic diagnostics for Korea superconducting tokamak advanced research
Authors: Lee S. G. , Bak J. G.
Published: February 2004

Magnetic diagnostics are essential tools for operation and control of the Korea Superconducting Tokamak Advanced Research (KSTAR) device and for understanding the plasma behavior. For this purpose, a concept and preliminary engineering design for the KSTAR magnetic diagnostics have been prepared. An overview and engineering design of the KSTAR magnetic diagnostics are presented.
Fast electron temperature diagnostic based on Langmuir probe current harmonic detection on DIII-D
Authors: Rudakov D. L. , Boedo J. A. , Moyer R. A. , Lehmer R. D. , Gunner G. , Watkins J. G.
Published: February 2004

A method for the measurement of electron temperature with high spatial and temporal resolution was recently implemented on a fast reciprocating probe on the DIII-D tokamak. The technique, previously used on the Torus Experiment for Technology Oriented Research, is based on detection of harmonics generated in the current spectrum of a single Langmuir probe driven by high-frequency sinusoidal voltage. The method was implemented on DIII-D with a drive frequency of 400 kHz and with improvements such as fully digital processing and active voltage feedback, thus allowing temperature measurements with a bandwidth of up to 200 kHz. Probe voltage and current were recorded at the sampling rate of 5 MHz and the amplitudes of the first (400 kHz) and the second (800 kHz) current harmonics were extracted by digital filtering. Digital processing does not introduce any phase delays (as analog detection does), making the technique suitable for correlation measurements. Electron temperatures obtained from the harmonic diagnostic are in reasonable agreement with swept double probe and Thomson scattering data. First measurements of the conductive turbulent heat flux in DIII-D have been performed. The measured values of the heat flux are consistent with the power balance.