bluuebunny/crossref_metadata_2025 huggingface dataset:
PROPRIETARY CLAIMS AND HUMAN RIGHTS—A “RESERVOIR OF ENTITLEMENT”?
Authors: Goymour Amy
Published: November 2006

TWO important decisions have recently considered the effect of human rights law on domestic property law: Kay v. Lambeth L.B.C.; Leeds C.C. v. Price, and J.A. Pye (Oxford) Ltd. v. United Kingdom. In each case, the claimant brought a domestic proprietary claim, one successfully, the other unsuccessfully, against a defendant. The aggrieved party argued that the domestic legal outcome conflicted with his rights under the European Convention on Human Rights. In each case, the court had to decide whether the Convention had indeed been infringed by the bringing of a proprietary claim and, if so, what the consequences of that infringement might be.
Understanding submucosal electrosurgery for the treatment of nasal turbinate enlargement
Authors: Farmer S E J , Eccles R
Published: November 2006

The surgical management of inferior turbinate enlargement is controversial. Submucosal electrosurgical techniques for turbinate reduction include conventional diathermy, radiofrequency tissue reduction and coblation. All electrosurgical techniques use radiofrequency electricity to damage turbinate tissue but differ in the control and delivery of energy. This review will examine the history of submucosal electrosurgery and clarify the various techniques. This review will also examine the evidence for the efficacy and safety of electrosurgery for the treatment of nasal turbinate enlargement, and will make a case that no progress will be made in clinical trials on the safety and efficacy unless there is standardisation of equipment and techniques in nasal electrosurgery.
Diagnostic adequacy and accuracy of fine needle aspiration cytology in neck lump assessment: results from a regional cancer network over a one year period
Authors: Howlett D C , Harper B , Quante M , Berresford A , Morley M , Grant J , Ramesar K , Barnes S
Published: November 2006

Aim: To establish the diagnostic accuracy and adequacy of fine needle aspiration cytology (FNAC) within a regional cancer network, and to determine what service improvements may be required to allow successful implementation of an FNAC-based, ‘one-stop’ head and neck clinic, as proposed by the current National Institute for Clinical Excellence guidelines.

Materials and methods: The Sussex cancer network serves a population of 1 200 000 and contains five hospitals within three acute trusts. In 2004, an audit was undertaken retrospectively to examine the diagnostic adequacy and accuracy of head and neck FNAC across the network. Comparisons were then made with the results of subsequent relevant surgery. For the purposes of the audit, FNAC was subdivided into three main groups: salivary gland, thyroid gland and neck node. As part of the data analysis, we also noted the clinical source of the FNAC and whether it was performed blind or under image guidance.

Results: In 2004, 712 FNAC procedures were undertaken in 647 patients, 276 of whom underwent subsequent surgery. Fine needle aspiration cytology was non-diagnostic in 52 per cent of patients in the neck node group, in 50 per cent in the salivary gland group and in 30 per cent in the thyroid group. With these non-diagnostic results removed, statistical analysis was performed on data from those patients who had undergone both FNAC and subsequent surgery. This gave a sensitivity of 89 per cent and a specificity of 57 per cent in the neck node group, a sensitivity of 64 per cent and specificity of 100 per cent in the salivary gland group, and a sensitivity of 62 per cent and specificity of 86 per cent in the thyroid group. Diagnostic problems with FNAC were noted, particularly in the differentiation of reactive nodal hyperplasia from lymphoma and in diagnosing follicular thyroid lesions. Ultrasound guidance was used in 50 per cent of the thyroid FNAC procedures but in only a minority of patients in the neck node and salivary gland groups.

Conclusion: This audit demonstrated widespread diagnostic difficulties associated with head and neck FNAC in a large patient sample. It is likely that these problems will be mirrored in other cancer networks. In order for one-stop head and neck clinics to succeed, the non-diagnostic rate of FNAC in particular must be minimised. There are strategies to enable this, depending on local resources, including increased access to cytologists or cytology technicians, diagnostic ultrasound, image guidance for FNAC and the use of ultrasound-guided core biopsy.
Designing robot grippers: optimal edge contacts for part alignment
Authors: Zhang Mike Tao , Goldberg Ken
Published: November 2006

Although parallel-jaw grippers play a vital role in automated manufacturing, gripper surfaces are still designed by trial-and-error. This paper presents an algorithmic approach to designing gripper jaws that mechanically align parts in the vertical (gravitational) plane. We consider optimal edge contacts, based on modular trapezoidal segments that maximize contact between the gripper and the part at its desired final orientation. Given then-sided 2D projection of an extruded convex polygonal part, mechanical properties such as friction and center of mass, and initial and desired final orientations, we present anO(n3logn) numerical algorithm to design optimal gripper jaws. We also present anO(nlogn) algorithm to compute tolerance classes for these jaws, and report on an online implemented version of the algorithm and physical experiments with the jaws it designed. This paper extends earlier results that generated optimal point contacts [M. T. Zhang and K. Goldberg, “Gripper point contacts for part alignment,”IEEE Trans. Robot. Autom.18(6), 902–910 (2002)].
Survey on the occurrence ofBrachyspiraspecies andLawsonia intracellularisin children living on pig farms
Authors: JACOBSON M. , RÅSBÄCK T. , FLÖISTRUP H. , BENZ M. , BRAUN-FAHRLÄNDER C. , RIEDLER J. , SCHRAM-BIJKERK D. , FELLSTRÖM C.
Published: November 2006

The occurrence ofBrachyspiraspecies andLawsonia intracellulariswas investigated by PCR analyses of faeces from 60 children living on European pig farms. In addition, 60 other children were included as controls. Two samples were positive forB. aalborgibutB. pilosicoliandL. intracellulariswere not demonstrated.
RESOLVING THE LIQUIDITY PUZZLE
Authors: SERLETIS APOSTOLOS , CHWEE VICTOR
Published: November 2006

This paper considers a nonborrowed-monetary-base VAR and a targets
and instrument framework favored by the monetarists to resolve the
puzzles thrown up by monetary VAR studies. The results show that
nonborrowed-monetary-base shocks produce responses consistent with a
priori expectations about the effects of monetary policy on interest
rates, prices, and output.
The use of a laser scanning digitiser to assess the accuracy of immobilisation masks
Authors: Cowley I. R. , Thomas S. J.
Published: November 2006

The accuracy of a range of immobilisation systems for head and neck radiotherapy has been measured. Two types of vacuum-formed shells, and eight thermoplastic systems have been evaluated. For each system, a mask was made for the same volunteer. A non-invasive optical system, using a scanning laser digitiser, was used to measure the displacement of a fiducial marker. The volunteer was asked to move a maximum comfortable distance in each of the superior, inferior, left and right directions, and a scan was taken at each location. Standard deviations, calculated from the maximum range of movements, were in the range of 1.7–2.9mm in the right–left direction, and 0.9–3.0mm in the superior–inferior direction. The smallest movements were measured for the Medtec S-frame, with nine-point fixation. A laser-scanning camera can assess the movement potential for a subject inside an immobilisation device with good accuracy and precision. Because ionising radiation is not used as part of the imaging process, the same subject can be used for several mask systems to assess which is the best one.
An observer study: comparison of computed radiography to electronic and film portal imaging
Authors: Roberts N. , Stanley S.
Published: November 2006

Introduction: Computed radiography (CR) is an imaging facility that does not require the use of hard copy film, digital images are obtained with a photostimulable phosphor plate, which replaces film, in a cassette. As the first UK radiotherapy site to trial CR, we are collecting data to assess the feasibility of using CR in radiotherapy treatment verification.

Method: From 30 patients undergoing radical radiotherapy, 10 were consecutively accrued to three sites: pelvis, thorax and head and neck. Treatment verification images were taken using current protocols, but substituting standard imaging for CR images on one fraction. Four independent observers were used: two clinical oncologists and two therapy radiographers. Observers rated CR, electronic portal imaging (EPI) and enhanced contrast (EC) films of the three sites for both landmark visibility and ease of verification decision, using a numerical scoring system.

Results: Ratings for visibility of landmarks and for verification decision were similar for CR and film/EPI images for most landmarks. However, CR images rated poorly compared to EC film in the head and neck region with landmarks such as thyroid cartilage and cricoid cartilage rating as ‘not clear’. CR images rated better than EPI images for both visibility and verification decision on the majority of landmarks in the pelvis region.

Conclusion: Results gathered from a relatively small sample size have provided the following conclusion. The visibility of landmarks in CR images is comparable to that in film and EPI. Verification of treatment images based on CR is comparable to that of the current imaging media in the department.
Primary anal adenocarcinoma: a caution for conservative treatment
Authors: Martin J. , Ngan S. Y. K. , Leong T.
Published: November 2006

There is evidence that a conservative approach with chemoradiotherapy can achieve long-term local control in patients with anal adenocarcinoma. Identification of suitable patients for this approach remains a problem. We describe a patient with a clinically staged T2N0 tumour, who achieved a complete clinical response on magnetic resonance imaging and positron emission tomography after chemoradiotherapy, but was noted to have residual disease with evidence of lymph node metastasis on pathological examination in the abdominoperineal resection specimen. A complete clinical response does not necessarily equate to pathological response.
Die Krankengeschichte, die sich nicht erzählen liess
Authors: Candinas
Published: November 2006

Durch den Mahnfinger eines Chefredaktors animiert, macht sich ein Arzt, der auf die Mitte seines Lebens zusteuert, Gedanken über Struktur seiner Beziehung zu Patienten und entdeckt das Prinzip der Zwiebelschale. Eine nur teilweise ernst zu nehmende Geschichte mit persönlicher Note in Essayform.
Somnolenz unklarer Provenienz – krankheits- oder medikamentös bedingt?
Authors: Hug
Published: November 2006

Eine 64-jährige Patientin mit bekannter Temporallappenepilepsie wurde zur weiteren Abklärung bei einer Somnolenz unklarer Ätiologie auf die Notfallstation (NFS) zugewiesen. Die Differentialdiagnose blieb eine Herausforderung auch nach Ausschluss einer kraniellen Raumforderung und eines Status epilepticus. Einerseits sind bei Patienten mit bekannter Temporallappenepilepsie psychiatrische Veränderungen mit Dämmerzuständen bekannt und andererseits sind diese Patienten oft wie unsere Patientin polymediziert. Die Medikamentenanamnese kann hier zentral und wegweisend sein, wie auch die Messung von Medikamentenspiegeln im Serum. Medikationsfehler respektive Adverse Drug Events (ADE) sind ein wichtiger Faktor auf NFS: rund 5% der Patienten sind betroffen und rund 3% der Spitaleinweisungen finden aufgrund eines ADE statt. Dies obwohl rund drei Viertel der ADEs verhinderbar wären.
Diagnostic Assessment of Learning Disabilities: From Assessment of Performance To Assessment of Competence
Authors: Grégoire Jacques
Published: November 2006

Models underlying diagnostic assessment of learning disabilities are seldom explained and discussed. More often too, those assessments are offered without empirical support. The goal of the current paper is to reflect on the diagnostic assessment of learning disabilities. A distinction can be made between assessments which focus on performance and those which focus on competence. Competence-based diagnostic assessments provide more useful information to practitioners to understand learning disabilities and to organize special education. Historically, the Piagetian theory opened the way to assessments of competence. But the assessments based on Piagetian theory suffer from methodological shortcomings. In this paper, significant changes for diagnostic assessments which are due to the recent development of cognitive psychology are emphasized.
Test Use Among School Psychologists: Past, Current, and Emerging Practices
Authors: Oakland Thomas
Published: November 2006

Current test use with children and youth, principally by school or educational psychologists, is reviewed. Issues discussed include the status of the specialty of school psychology, a brief history of educational and psychological testing, traditional purposes of and common problems associated with test use, and emerging trends. Emphasis is placed on conditions within Europe when possible.
Towards an Integrated Testing Service System
Authors: Glas C. A. W.
Published: November 2006

In a testing service system (TSS) the activities that play a role in educational and psychological assessment are integrated and, as far as possible, computerized. Such systems will be the basis for test design, administration, analysis, and reporting in the next century. The main activities in a Testing Service System are item banking, item construction, test assembly, test administration, test analysis, and calibration. Testing service systems exist in various forms, ranging from general-purpose software packages to systems especially developed to support specific organizations and the administration of specific tests. With the advent of Windows technology, both individual professionals and testing organizations are more and more in a position to create a tailor-made TSS by linking existing software elements that have the functionality suited to the demands of the situation. In this paper, a number of the considerations that play a role in designing a TSS are described.
Providing Data for Educational Policy in an International Context: The Third International Mathematics and Science Study (TIMSS)
Authors: Beaton Albert E. , Martin Michael O. , Mullis Ina V.S.
Published: November 2006

Policy-makers in many nations of the world are involved in educational reforms. In order to make effective educational decisions for the 21st century, policy-makers need information of a wide variety of kinds, for example, comparative performance data and curriculum information from other nations. National assessments can be valuable, but international surveys provide a broader base of information and allow countries to view their current status and planning within an international perspective. The purpose of this paper is to describe the goals of the Third International Mathematics and Science Study and the steps being followed to insure that the results from the study will meet the diverse informational needs of policy-makers.
New primary production and nitrification in the western subtropical North Atlantic: A modeling study
Authors: Martin A. P. , Pondaven P.
Published: November 2006

The original definition of new primary production rests on the assumption that nitrogenous substrate taken up to fuel algal growth is coming into contact with phytoplankton for the first time that year. Therefore, should the generation of nitrate from ammonium by nitrification turn out to be significant in surface waters then nitrate uptake can no longer be simply ascribed to new production. A modeling study is presented centered on the Bermuda Atlantic Time‐series Station, in the oligotrophic subtropical North Atlantic. We quantify the role of nitrification in providing nitrate to fuel primary production through a full annual cycle for the first time. The results confirm previous limited observations suggesting that a major fraction of nitrate uptake in oligotrophic regions (where nitrification will be most influential), previously ascribed to new production, may actually involve “recycled” nitrate.
Strontium to calcium ratios in the marine gastropod Conus ermineus: Growth rate effects and temperature calibration
Authors: Sosdian Sindia , Gentry D. Keith , Lear Caroline H. , Grossman Ethan L. , Hicks David , Rosenthal Yair
Published: November 2006

Here we investigate the potential of Sr/Ca ratios in the marine gastropod Conus ermineus for reconstructing seawater temperatures. We present annually resolved records of Sr/Ca and δ18O for four shells collected alive from the Flower Garden Banks National Marine Sanctuary in the Gulf of Mexico. Our results show that variations in Sr/Ca and δ18O covary with the in situ seasonal temperature cycle. Sr/Ca and temperature are positively correlated, in contrast with the inverse relationship found in inorganically precipitated aragonite. The seasonal Sr/Ca variability is superimposed on a long‐term trend of increasing Sr/Ca with age. Both the seasonal and long‐term ontogenetic changes in Sr/Ca are associated with variations in growth rate, defined here as the shell linear extension rate (LER); the seasonal variability in LER is superimposed on a long‐term decrease with ontogeny. Thus the covariance of Sr/Ca ratios with temperature and LER suggests that Sr incorporation is likely driven by temperature influence on growth rate, rather than by thermodynamic effects. Unlike the seasonal variability, the ontogenetic effect is characterized by inverse covariation between Sr/Ca and LER, suggesting that Sr/Ca variability is not controlled by growth rate alone, but probably by two different biomineralization mechanisms, one related to temperature and the other related to age. We use the seasonal Sr/Ca signal of four shells to construct a temperature calibration. To minimize the ontogenetic effects, we separate the records into juvenile and adult growth stages and calculate the Sr/Ca‐temperature (T) relationships: Juvenile: Sr/Ca (mmol mol−1) = 0.042 (±0.008) * T (°C) + 0.24 (±0.21) (R2 = 0.66) Adult: Sr/Ca(mmol mol−1) = 0.072 (±0.014) * T (°C) − 0.05 (±0.34) (R2 = 0.68) Applying the calibration to a single specimen provides mean annual temperature estimates within ±1°C of the in situ temperature record but resolves the seasonal variability only within ±3.5°C. The large error in the seasonal estimates reflects the high variability among specimens. To reduce the uncertainty on seasonal temperatures, we propose combining records from multiple shells to generate an average temperature record. The potential of this approach needs, however, to be validated in other locations.
Miocene rifting of Fuerteventura (Canary Islands)
Authors: Fernández Carlos , Casillas Ramón , García Navarro Encarnación , Gutiérrez Margarita , Camacho Manuel A. , Ahijado Agustina
Published: November 2006

The older geological units of the volcanic island of Fuerteventura (Canary Islands), i.e., the so‐called basal complex and the lower part of the subaerial volcanic rocks, show abundant structures indicative of a long‐lived period of Miocene tectonic activity. These structures include faults, dike swarms, kilometer‐scale folds, tilted sequences, and fissural and central volcanic edifices. A detailed structural study, based on geological mapping and the use of fault slip inversion techniques and statistical analysis of dike orientation, has allowed the identification of three separated Miocene deformation phases: M‐D1, M‐D2, and M‐D3. The average extension directions determined for these phases are NW‐SE, NNE‐SSW, and ENE‐WSW, respectively. A model of oceanic lithosphere rifting is proposed to account for this deformation history. A buoyant, anomalous sublithosphere mantle triggered the extension in the lithosphere beneath Fuerteventura, isolating it during the early and middle Miocene from the plate‐scale collision regime predominant in the NW corner of the African plate.
New drought frequency index: Definition and comparative performance analysis
Authors: González Javier , Valdés Juan B.
Published: November 2006

Drought periods appear as extreme events whose characterization encompasses several issues. Many issues are related to the multiple natures that a drought may have: meteorological, hydrological, agricultural, or socioeconomical. There are also issues related to the complexity of the phenomena, which may be characterized by many magnitudes, such as duration, severity, or intensity. None of them alone may be used as a general drought characterization criterion. Others arise from the kind of methodologies that are available for their significance evaluation, which focus on different aspects for specific objectives. However, most have a common aspect: the extreme persistent realization of a random hydroclimatic variable. For the goal of general drought analysis, in this paper a new index for drought characterization is presented: the drought frequency index (DFI). The index focuses on this common aspect of the drought origins, with a purely probabilistic treatment. Because droughts are persistent phenomena, the index is based on the stochastic characterization of extreme persistent deviation sequences using a novel probabilistic criterion. In this way, the DFI is related to the mean frequency of recurrence of extreme persistent events. Therefore the mean frequency of recurrence is adopted as the scale for drought significance evaluation. The index performance is analyzed and compared with respect to the different issues that result from applying other methodologies: magnitude selection, univariate versus multivariate, threshold selection (related to the run theory), and timescale issues (related with the standard precipitation index (SPI) application). Furthermore, to apply runs theory for any magnitude number, an original generalization of drought multivariate recurrence models is presented. Finally, the spatial comparability of the indexes is analyzed. Results reveal the ability of the DFI to reduce the sensitivity to practical issues. The DFI provides a consistent index for spatial comparisons and for application to general drought characterization goals.
Optimal reservoir operation considering the water quality issues: A stochastic conflict resolution approach
Authors: Kerachian Reza , Karamouz Mohammad
Published: November 2006

In this study, an algorithm combining a water quality simulation model and a deterministic/stochastic conflict resolution technique is developed for determining optimal reservoir operating rules. As different decision makers and stakeholders are involved in reservoir operation, the Nash bargaining theory is used to resolve the existing conflict of interests. The utility functions of the proposed models are developed on the basis of the reliability of the water supply to downstream demands, water storage, and the quality of the withdrawn water. The expected value on the Nash product is considered as the objective function of the stochastic model, which can incorporate the inherent uncertainty of reservoir inflow. A water quality simulation model is also developed to simulate the thermal stratification cycle and the reservoir discharge quality through a selective withdrawal structure. The optimization models are solved using a new version of genetic algorithms called varying chromosome length genetic algorithm (VLGA). In this algorithm the chromosome length is sequentially increased to provide a good initial solution for the final traditional GA‐based optimization model. The proposed stochastic optimization model can also reduce the computational burden of the previously proposed models such as stochastic dynamic programming (SDP) by reducing the number of state transitions in each stage. The proposed models which are called VLGAQ and SVLGAQ are applied to the 15‐Khordad Reservoir in the central part of Iran. The results show that the proposed models can reduce the salinity of allocated water to different water demands as well as the salinity buildup in the reservoir.
Comparative impact of climatic and nonclimatic factors on global terrestrial carbon and water cycles
Authors: Müller Christoph , Bondeau Alberte , Lotze‐Campen Hermann , Cramer Wolfgang , Lucht Wolfgang
Published: November 2006

The coupled global carbon and water cycles are influenced by multiple factors of human activity such as fossil‐fuel emissions and land use change. We used the LPJmL Dynamic Global Vegetation Model (DGVM) to quantify the potential influences of human demography, diet, and land allocation, and compare these to the effects of fossil‐fuel emissions and corresponding climate change. For this purpose, we generate 12 land use patterns in which these factors are analyzed in a comparative static setting, providing information on their relative importance and the range of potential impacts on the terrestrial carbon and water balance. We show that these aspects of human interference are equally important to climate change and historic fossil‐fuel emissions for global carbon stocks but less important for net primary production (NPP). Demand for agricultural area and thus the magnitude of impacts on the carbon and water cycles are mainly determined by constraints on localizing agricultural production and modulated by total demand for agricultural products.
Cloudless aerosol forcing efficiency in the UV region from AERONET and WOUDC databases
Authors: García O. E. , Díaz A. M. , Expósito F. J. , Díaz J. P. , Gröbner J. , Fioletov V. E.
Published: November 2006

Aerosol Robotic Network (AERONET) and World Ozone and Ultraviolet Data Center (WOUDC) combined information have been used to calculate the aerosol forcing efficiency under cloud‐free conditions, ΔFe, in the ultraviolet region (290–325 nm) at surface. The stations of these global networks have been collocated spatial and temporarily, resulting three common stations: two in Canada, representative of background conditions (Bratt's Lake and Saturna Island) and one in Italy, characterized by rural and industrial aerosols (Ispra). The monthly ΔFe was calculated during spring and summer time in the common period, 1999 to 2004, and for the Cimel wavelengths 500, 440, 380 and 340 nm. The ΔFe values range from −0.65 ± 0.07 Wm−2/τ500 to −0.36 ± 0.03 Wm−2/τ340 for Ispra, whereas for the Canadian observatories the interval varies from −2.07 ± 0.62 Wm−2/τ500 to −0.16 ± 0.23 Wm−2/τ340. No significant annual or seasonal trends for the ΔFe were found in any station.
Does kinematic advection by superimposed waves provide an explanation for quasi‐universal gravity‐wave spectra?
Authors: Klaassen G. P. , Sonmor L. J.
Published: November 2006

Earlier work has indicated that kinematic advection associated with a linear superposition of standing sinusoidal Lagrangian gravity waves generates, at sufficiently high amplitudes, nonsinusoidal Eulerian perturbations and broadened vertical wavenumber spectra. We find that those same Lagrangian waves also produce singularities in the Eulerian fields. Even at the lowest wave amplitudes consistent with observations of saturated atmospheric waves, we find that kinematic parcel compressions are still far too large compared to adiabatic constraints, while the spectral broadening is far weaker than that indicated by atmospheric measurements. These results demonstrate that kinematic advection by linear Lagrangian waves cannot provide a suitable basis for understanding at least some saturated wave spectra.
Uranium in the Earth's lower mantle
Authors: Gautron Laurent , Greaux Steeve , Andrault Denis , Bolfan‐Casanova Nathalie , Guignot Nicolas , Bouhifd M. Ali
Published: November 2006

The distribution of the radiogenic heat sources strongly influences the geodynamics and thermal behaviour of the Earth. About 11 TW is produced by the radioactive decay of uranium (25% of the total heat flux at Earth surface), and 55% of this energy comes from the lower mantle. Here we report the first experimental evidence that aluminous CaSiO3 perovskite is the major, or even the only, host of uranium in the Earth lower mantle, since such a phase is able to incorporate up to 35 wt% UO2 (or 4 at% of U). The aluminous Ca‐perovskite could be the main U‐bearing constituent of a dense and radiogenic reservoir proposed in a recent model and located in the bottom half of the lower mantle.
Runaway breakdown in the Jovian atmospheres
Authors: Dwyer J. R. , Coleman L. M. , Lopez R. , Saleh Z. , Concha D. , Brown M. , Rassoul H. K.
Published: November 2006

Using detailed Monte Carlo calculations, the properties of runaway breakdown in the atmospheres of the four gas giant planets in our solar system are investigated, and the runaway avalanche lengths and average runaway electron kinetic energies are presented as a function of atmospheric electric field strengths. The runaway breakdown threshold field for the Jovian atmospheres is found to be 10 times smaller than the conventional breakdown field when hydrometeors are present, compared to 3 times smaller for Earth's atmosphere, indicating that runaway breakdown processes may be much more efficient in the gas giants than on Earth. In the Earth's atmosphere, runaway breakdown is known to produce large bursts of x‐rays and gamma‐rays from thunderstorms, such as terrestrial gamma‐ray flashes, and may play a role in lightning initiation. These results suggest that runaway breakdown may play an important role in thunderstorm and lightning processes on the Jovian planets as well.
Sulfur cycle at Last Glacial Maximum: Model results versus Antarctic ice core data
Authors: Castebrunet H. , Genthon C. , Martinerie P.
Published: November 2006

For the first time, an atmospheric general circulation and sulfur chemistry model is used to simulate sulfur deposition in Antarctica at the Last Glacial Maximum (LGM). Dimethylsulfide (DMS), emitted by phytoplankton, is the dominant source of atmospheric sulfur in Antarctica. Once in the atmosphere, it is oxidized into sulfur aerosols which are measured in ice cores. Such measurements allow for validating climate and chemistry models for glacial‐interglacial changes. Our glacial simulations test the effect of a recent re‐evaluation of glacial sea‐ice coverage on DMS sources and sulfur aerosol deposition. Using the present‐day oceanic concentrations of DMS, the model reproduces observed glacial and interglacial sulfur concentrations in the ice. This result suggests that climate change at the LGM did not greatly impact on DMS production in the oceanic sectors where sulfur aerosols deposited in central East Antarctica originate from.
On the mechanism of blue jet formation and propagation
Authors: Raizer Y. P. , Milikh G. M. , Shneider M. N.
Published: November 2006

A new model of blue jets is proposed. A blue jet consists of an upward propagating leader whose top part is seen on photos as a “trunk of a tree”, and is capped at the top side of the leader by its streamer zone. The latter is shown as tall and narrow branches of “the tree”. It is shown that blue jet streamers can be sustained by relatively moderate cloud charges due to upward transfer of the high thundercloud potential by the leader. The streamer length is estimated along with the height at which the streamers can reach the ionosphere. The propagation of a streamer in the atmosphere of exponentially falling density N is computed. It is found that the critical external field ES required for unlimited streamer growth satisfies the similarity law ES/N ∼ const. Shortcomings of the existing blue jet models are discussed.
Solar Mass Ejection Imager (SMEI) observations of coronal mass ejections (CMEs) in the heliosphere
Authors: Webb D. F. , Mizuno D. R. , Buffington A. , Cooke M. P. , Eyles C. J. , Fry C. D. , Gentile L. C. , Hick P. P. , Holladay P. E. , Howard T. A. , Hewitt J. G. , Jackson B. V. , Johnston J. C. , Kuchar T. A. , Mozer J. B. , Price S. , Radick R. R. , Simnett G. M. , Tappin S. J.
Published: November 2006

The Solar Mass Ejection Imager (SMEI) on the Coriolis spacecraft has been obtaining white light images of nearly the full sky every 102 minutes for three years. We present statistical results of analysis of the SMEI observations of coronal mass ejections (CMEs) traveling through the inner heliosphere; 139 CMEs were observed during the first 1.5 years of operations. At least 30 of these CMEs were observed by SMEI to propagate out to 1 AU and beyond and were associated with major geomagnetic storms at Earth. Most of these were observed as frontside halo events by the SOHO LASCO coronagraphs.
Phase space density distributions of energetic electrons in the outer radiation belt during two Geospace Environment Modeling Inner Magnetosphere/Storms selected storms
Authors: Chen Y. , Friedel R. H. W. , Reeves G. D.
Published: November 2006

The phase space density distributions of energetic electrons during two storm periods, including the two storms on 21–23 October 2001 and 4–9 September 2002 selected by Geospace Environment Modeling Inner Magnetosphere/Storms campaign as the radiation belt assessment challenge in 2004 workshop, are presented in this paper. Electron data from the Synchronous Orbit Particle Analysis instrument aboard three Los Alamos National Laboratory geosynchronous satellites as well as the Comprehensive Energetic Particle and Pitch Angle Distribution instrument aboard Polar are used. The Tsyganenko 2001 storm model is chosen for the storm time magnetic field presentation, compared to the best‐fitting magnetic model achieved in a previous study. By tracing the temporally evolving radial distributions, we conclude that while the dropout of electron phase space density during storm main phases appears to be energy‐independent, the enhancement in recovery phases shows an energy‐dependent pattern. The average outwardly decreasing radial gradients of phase space density obtained during the recovery phases of the two storm periods strongly suggest the in situ acceleration is most likely the main source of new energetic electrons, along with a possible contribution from an external source.
Mean and gravity wave structures and variability in the Mars upper atmosphere inferred from Mars Global Surveyor and Mars Odyssey aerobraking densities
Authors: Fritts David C. , Wang Ling , Tolson Robert H.
Published: November 2006

We have used density measurements obtained during aerobraking (AB) on Mars Global Surveyor and Mars Odyssey to examine mean densities and the characteristics and variability of gravity waves (GWs) in the upper atmosphere of Mars. Mean densities exhibit variability with latitude and season and in response to variable forcing and filtering from below. These data also reveal significant variability of GWs, both spatially and temporally. In general, GW amplitudes increase, while apparent horizontal scales remain the same, with increasing altitude. The dominant spatial scales at the lower AB altitudes are typically ∼20–200 km and density fluctuations vary from ∼5 to 50%, though even larger values are occasionally observed. GW amplitudes also vary significantly with season, being generally larger in winter and at middle and high latitudes, and apparently reflecting mean source and filtering conditions. Amplitudes also appear to vary with longitude and time and may provide clues to variability of, and interactions with, larger‐scale motions.
Climatologies of nighttime upper thermospheric winds measured by ground‐based Fabry‐Perot interferometers during geomagnetically quiet conditions: 1. Local time, latitudinal, seasonal, and solar cycle dependence
Authors: Emmert J. T. , Faivre M. L. , Hernandez G. , Jarvis M. J. , Meriwether J. W. , Niciejewski R. J. , Sipler D. P. , Tepley C. A.
Published: November 2006

We analyze ground‐based Fabry‐Perot interferometer observations of upper thermospheric (∼250 km) horizontal neutral winds derived from Doppler shifts in the 630.0 nm (red line) nightglow. The winds were measured over the following locations: South Pole (90°S), Halley (76°S, 27°W), Arequipa (17°S, 72°W), Arecibo (18°N, 67°W), Millstone Hill (43°N, 72°W), Søndre Strømfjord (67°N, 51°W), and Thule (77°N, 68°W). We derive climatological quiet time (Kp < 3) wind patterns as a function of local time, solar cycle, day of year, and the interplanetary magnetic field (IMF), and provide parameterized representations of these patterns. At the high‐latitude stations, and at Arequipa near the geomagnetic equator, wind speeds tend to increase with increasing solar extreme ultraviolet (EUV) irradiance. Over Millstone Hill and Arecibo, solar EUV has a negative effect on wind magnitudes. As represented by the 10.7 cm radio flux proxy, the solar EUV dependence of the winds at all latitudes is characterized by a saturation or weakening of the effect above moderate values (F10.7 > 150). The seasonal dependence of the winds is generally annual, but there are isolated cases in which a semiannual variation is observed. Within the austral winter, winds measured from the South Pole show a substantial intraseasonal variation only along longitudes directed toward the magnetic pole. IMF effects are described in a companion paper.
Differences between transmitter precipitation peaks and storm injection peaks in low‐altitude energetic electron spectra
Authors: Datlowe Dayton
Published: November 2006

Peaks in the energy spectrum of energetic radiation belt electrons (100 keV to 1 MeV) are evidence of pitch angle scattering by wave‐particle interactions. Low‐altitude satellites in the inner magnetosphere have reported two types of spectral peaks, corresponding to two different scattering mechanisms. However, previously published reports have focused on either on one type or on the other type of peak. We present here a side‐by‐side comparison of the two kinds of spectral phenomena in order to make clear the differences between them.
X rays and solar wind composition in four comets observed with Chandra X‐Ray Observatory
Authors: Krasnopolsky Vladimir A.
Published: November 2006

X‐ray spectra of four comets measured with Chandra X‐Ray Observatory (CXO) have been uniformly processed and analyzed. Some tools have been developed that make it possible to extract abundances of C+5, C+6, O+7, O+8, and Ne+9 in the solar wind around comets from their X‐ray spectra. Despite the low resolving power E/δE ≈ 5, quantitative spectroscopic analysis has been successfully applied to the CXO spectra of comets. The retrieved C+5 and O+7 abundances are corrected for contributions of the secondary ions produced by charge exchange of C+6 and O+8, respectively. The data from four comets reveal significant variability of the flow, chemical composition, and charge state in the solar wind. The C+6/C+5 ratios correlate with those of O+8/O+7 and indicate that the solar wind was slow near comet T1, fast near comets Q4 and Encke, and medium near comet S4. The mean temperature of Ne extracted from the Ne+9 abundances agrees with those from the O+8/O+7 ratios. The heavy ion flow in the solar wind varies from comet Q4 to comet T1 by a factor of 12 being near the mean value in comet Encke that was observed for a long exposure time. Coincidence of the O+8/O+7 ratios extracted independently from two line pairs and the excellent correlation between C+6/C+5 and O+8/O+7 demonstrate the high accuracy of the method. X‐ray spectroscopy of comets may be used for diagnostics of the solar wind at large distances from the Earth.
Multivectorial paleointensity determination by the Thellier method
Authors: Shcherbakov V. P. , Zhidkov G. V.
Published: November 2006

Theoretical and experimental study of shape of the Arai‐Nagata diagrams for the natural remanent magnetization (NRM) consisting of two low‐ and high‐temperature partial thermal remanent magnetization vectors directed at angle θ to each other is considered. Assuming that the NRM is carried by single‐domain and/or small pseudosingle‐domain grains, that is, the Thellier laws of additivity and independence are valid, a theoretical consideration showed that the low‐temperature portion of the diagram has a hyperbolic shape. A striking feature of the diagram is that at obtuse angle θ and strong enough low‐temperature component it exhibits a minimum. The theoretical conclusions were examined experimentally; the results of the experiments are in a good agreement with the theoretical predictions. The shape of the low‐temperature portion is predetermined by the angle θ, the relative intensity of low‐temperature component, and the field h in which this component was imparted. These three parameters can be found from the results of Thellier experiments by the least squares method. It opens a way to determine the paleofield h and the angle θ which are characteristics of the low‐temperature (presumably secondary) remanent magnetization. A few examples of such the determinations on samples from Proterozoic collections are reported.
A global inventory of stratospheric chlorine in 2004
Authors: Nassar R. , Bernath P. F. , Boone C. D. , Clerbaux C. , Coheur P. F. , Dufour G. , Froidevaux L. , Mahieu E. , McConnell J. C. , McLeod S. D. , Murtagh D. P. , Rinsland C. P. , Semeniuk K. , Skelton R. , Walker K. A. , Zander R.
Published: November 2006

Total chlorine (ClTOT) in the stratosphere has been determined using the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE‐FTS) measurements of HCl, ClONO2, CH3Cl, CCl4, CCl3F (CFC‐11), CCl2F2 (CFC‐12), CHClF2 (HCFC‐22), CCl2FCClF2 (CFC‐113), CH3CClF2 (HCFC‐142b), COClF, and ClO supplemented by data from several other sources, including both measurements and models. Separate chlorine inventories were carried out in five latitude zones (60°–82°N, 30°–60°N, 30°S–30°N, 30°–60°S, and 60°–82°S), averaging the period of February 2004 to January 2005 inclusive, when possible, to deal with seasonal variations. The effect of diurnal variation was avoided by only using measurements taken at local sunset. Mean stratospheric ClTOT values of 3.65 ppbv were determined for both the northern and southern midlatitudes (with an estimated 1σ accuracy of ±0.13 ppbv and a precision of ±0.09 ppbv), accompanied by a slightly lower value in the tropics and slightly higher values at high latitudes. Stratospheric ClTOT profiles in all five latitude zones are nearly linear with a slight positive slope in ppbv/km. Both the observed slopes and pattern of latitudinal variation can be interpreted as evidence of the beginning of a decline in global stratospheric chlorine, which is qualitatively consistent with the mean stratospheric circulation pattern and time lag necessary for transport.
Observation of daytime N2O5 in the marine boundary layer during New England Air Quality Study–Intercontinental Transport and Chemical Transformation 2004
Authors: Osthoff Hans D. , Sommariva Roberto , Baynard Tahllee , Pettersson Anders , Williams Eric J. , Lerner Brian M. , Roberts James M. , Stark Harald , Goldan Paul D. , Kuster William C. , Bates Timothy S. , Coffman Derek , Ravishankara A. R. , Brown Steven S.
Published: November 2006

The nitrate radical, NO3, and dinitrogen pentoxide, N2O5, are key reactive nocturnal nitrogen oxides in the troposphere. The daytime impact of NO3 and N2O5, however, is restricted by photochemical recycling of NO3 to NO2 and O3. In this paper, we report daytime measurements of N2O5 on board the NOAA research vessel Ronald H. Brown in the Gulf of Maine during the New England Air Quality Study–Intercontinental Transport and Chemical Transformation (NEAQS‐ITCT) campaign in the summer of 2004. Daytime N2O5 mixing ratios of up to 4 pptv were observed, consistent with predictions from a steady state analysis. Predicted and observed NO3 mixing ratios were below the instrumental detection limit of ∼1 pptv; the average calculated concentration was 0.09 pptv. Important impacts of daytime NO3 and N2O5 in the marine boundary layer included increased rates of VOC oxidation (in particular dimethyl sulfide) and enhanced NOx to HNO3 conversion, both of which scaled with the available NOx. Smaller effects of daytime NO3 and N2O5 included chemical destruction of O3 and a shift of the NO2:NO ratio. Because the rates of heterogeneous conversion of N2O5 and NO3 to HNO3 scale with the surface area available for uptake, the importance of daytime fog is discussed.
On the use of MODIS EVI to assess gross primary productivity of North American ecosystems
Authors: Sims Daniel A. , Rahman Abdullah F. , Cordova Vicente D. , El‐Masri Bassil Z. , Baldocchi Dennis D. , Flanagan Lawrence B. , Goldstein Allen H. , Hollinger David Y. , Misson Laurent , Monson Russell K. , Oechel Walter C. , Schmid Hans P. , Wofsy Steven C. , Xu Liukang
Published: November 2006

Carbon flux models based on light use efficiency (LUE), such as the MOD17 algorithm, have proved difficult to parameterize because of uncertainties in the LUE term, which is usually estimated from meteorological variables available only at large spatial scales. In search of simpler models based entirely on remote‐sensing data, we examined direct relationships between the enhanced vegetation index (EVI) and gross primary productivity (GPP) measured at nine eddy covariance flux tower sites across North America. When data from the winter period of inactive photosynthesis were excluded, the overall relationship between EVI and tower GPP was better than that between MOD17 GPP and tower GPP. However, the EVI/GPP relationships vary between sites. Correlations between EVI and GPP were generally greater for deciduous than for evergreen sites. However, this correlation declined substantially only for sites with the smallest seasonal variation in EVI, suggesting that this relationship can be used for all but the most evergreen sites. Within sites dominated by either evergreen or deciduous species, seasonal variation in EVI was best explained by the severity of summer drought. Our results demonstrate that EVI alone can provide estimates of GPP that are as good as, if not better than, current versions of the MOD17 algorithm for many sites during the active period of photosynthesis. Preliminary data suggest that inclusion of other remote‐sensing products in addition to EVI, such as the MODIS land surface temperature (LST), may result in more robust models of carbon balance based entirely on remote‐sensing data.