bluuebunny/crossref_metadata_2025 huggingface dataset:
Cost and health status analysis after autologous chondrocyte implantation and mosaicplasty: A retrospective comparison
Authors: Derrett Sarah , Stokes Elizabeth A. , James Marilyn , Bartlett William , Bentley George
Published: April 2008

Objectives:Chondral defects of the knee cartilage are prevalent. Autologous chondrocyte implantation (ACI) and mosaicplasty are increasingly used to treat symptomatic knee defects. This study assessed the costs and health status outcomes after ACI and mosaicplasty.

Methods:Patients were eligible to participate in this cross-sectional study if they received ACI or mosaicplasty at the Royal National Orthopaedic Hospital between 1997 and 2001 or were on a waiting list for ACI. Secondary-care resource use was collected to 2 years postoperatively using a resource collection proforma. Participants responded to postal questions about sociodemographic characteristics and knee-related (Modified Cincinnati Knee Rating System) and general health status (EQ-5D).

Results:Fifty-three ACI, twenty mosaicplasty, and twenty-two patients waiting for ACI participated. The average cost per patient was higher for ACI (£10,600: 95 percent confidence interval [CI], £10,036–£11,214) than mosaicplasty (£7,948: 95 percent CI, £6,957–£9,243). Postoperatively, ACI and mosaicplasty patients (combined) experienced better health status than those waiting for ACI. ACI patients tended to have better health status outcomes than mosaicplasty patients (not statistically significant). Estimated average EQ-5D social tariff improvements for quality-adjusted life year (QALY) calculations were 0.23 (ACI) and 0.06 (mosaicplasty). Average costs per QALY were £23,043 (ACI) and £66,233 (mosaicplasty). The incremental cost effectiveness ratio (ICER) for providing ACI over mosaicplasty was £16,349.

Conclusions:Average costs were higher for ACI than mosaicplasty. However, both the estimated cost per QALY and ICER for providing ACI over mosaicplasty fell beneath an implicit English funding threshold of £30,000 per QALY. Prospective studies should include measures of utility to confirm the estimated cost utility ratios of ACI and mosaicplasty.
Diagnosis of appendicitis in adults by ultrasonography or computed tomography: A systematic review and meta-analysis
Authors: Weston Adèle R. , Jackson Terri J. , Blamey Stephen
Published: April 2008

Objectives:The use of ultrasonography and computed tomography (CT) in the diagnosis of appendicitis in adult patients was compared.

Methods:Systematic review and meta-analysis of current evidence in two clinical situations: unselected nonpregnant, adult patients with symptoms of appendicitis, and more selective use in only those patients who still have an equivocal diagnosis subsequent to routine clinical investigations.

Results:Meta-analysis of eligible studies shows CT to have better sensitivity and specificity than ultrasound in both clinical situations.

Conclusions:Application of these findings in clinical practice and/or policy would need to evaluate the better diagnostic performance of CT against its cost and availability. In addition, it is imperative that future studies be conducted in patient populations that are well-defined with respect to prior investigations. Sequelae of false-negative and false-positive diagnoses should also be evaluated.
Effects of continuing medical education on improving physician clinical care and patient health: A review of systematic reviews
Authors: Bloom Bernard S.
Published: April 2008

Objectives:The objective of physician continuing medical education (CME) is to help them keep abreast of advances in patient care, to accept new more-beneficial care, and discontinue use of existing lower-benefit diagnostic and therapeutic interventions. The goal of this review was to examine effectiveness of current CME tools and techniques in changing physician clinical practices and improving patient health outcomes.

Methods:Results of published systematic reviews were examined to determine the spectrum from most- to least-effective CME techniques. We searched multiple databases, from 1 January 1984 to 30 October 2004, for English-language, peer-reviewed meta-analyses and other systematic reviews of CME programs that alter physician behavior and/or patient outcomes.

Results:Twenty-six reviews met inclusion criteria, that is, were either formal meta-analyses or other systematic reviews. Interactive techniques (audit/feedback, academic detailing/outreach, and reminders) are the most effective at simultaneously changing physician care and patient outcomes. Clinical practice guidelines and opinion leaders are less effective. Didactic presentations and distributing printed information only have little or no beneficial effect in changing physician practice.

Conclusions:Even though the most-effective CME techniques have been proven, use of least-effective ones predominates. Such use of ineffective CME likely reduces patient care quality and raises costs for all, the worst of both worlds.
Decision making in general practice: The availability and use of a specific laboratory analysis
Authors: Fauli Siri , Thue Geir
Published: April 2008

Objectives:The aim of this investigation was to study the effect of general practitioners' (GP's) characteristics on two decisions: whether to have theHelicobacter pylorirapid test (HPRT) in the office laboratory and whether to use this test or a similar hospital-based serological test in a typical clinical situation described in a vignette.

Methods:Discrete choice analysis with binary logit models were used to predict the probability that a general practice has the HPRT, as well as the GP's probability of using the HPRT or a similar test in this clinical situation.

Results:We found that the number of consultations per week has a positive effect on the probability of having the HPRT, indicating that the size of the practice affects the decision to have such a test in the repertoire. Furthermore, four variables significantly increased the probability of using one of the lab tests: more if located in urban practices, more by solo practitioners, more when the GP stated a high probability forH. pyloriassociated disease, and more when the GP had the rapid test available in the practice. In our analysis, the remuneration system is endogenous and does not have a significant effect on the two decisions.

Conclusions:Our study demonstrates that characteristics of the GP affect the availability and use of a specific laboratory analysis.
Cluster randomized trials: Another problem for cost-effectiveness ratios
Authors: Flynn Terry N. , Peters Tim J.
Published: April 2008

Objectives:This work has investigated under what conditions cost-effectiveness data from a cluster randomized trial (CRT) are suitable for analysis using a cluster-adjusted nonparametric bootstrap. The bootstrap's main advantages are in dealing with skewed data and its ability to take correlations between costs and effects into account. However, there are known theoretical problems with a commonly used cluster bootstrap procedure, and the practical implications of these require investigation.

Methods:Simulations were used to estimate the coverage of confidence intervals around incremental cost-effectiveness ratios from CRTs using two bootstrap methods.

Results:The bootstrap gave excessively narrow confidence intervals, but there was evidence to suggest that, when the number of clusters per treatment arm exceeded 24, it might give acceptable results. The method that resampled individuals as well as clusters did not perform well when cost and effectiveness data were correlated.

Conclusions:If economic data from such trials are to be analyzed adequately, then there is a need for further investigations of more complex bootstrap procedures. Similarly, further research is required on methods such as the net benefit approach.
Validity of original studies in health technology assessment reports: Significance of standardized assessment and reporting
Authors: Porzsolt Franz , Kajnar Hana , Awa Aziz , Fässler Margrit , Herzberger Barbara
Published: April 2008

Objectives:As health technology assessments (HTA) may have considerable impact on health-care decisions, it is essential to guarantee the expected quality of these assessments. Variations in the methods used or lack of transparency can affect the important role of HTA reports.

Methods:In our study, we analyzed the methods used in two corresponding HTA reports to assess the validity of two key papers, which were included in both reports. Also the discussions and the final conclusions of both reports were compared.

Results:The authors of the two HTA reports used different instruments to assess the validity of the original studies. A minor problem is differences that were found in the assessments of identical validity aspects of the included studies and in the information provided in the HTA reports. A more serious problem was found in both HTA reports which identified the weakness of the key papers and expressed these limitations in the discussions (read mainly by scientists) but not in the conclusions (read mainly by policy-makers).

Conclusions:The results of this study may be important for any institution that prepares recommendations for policy-makers. In the case of HTA reports, no new checklists are necessary as the checklist offered by the INAHTA contains the needed information. It may be necessary, however, to consider an “intramural quality board,” which helps the member organizations guarantee both the transparency of the original studies included in HTA reports and the transparency of the HTA report itself.
“Soul Is But Harmony”: David Josef Bach and the Workers' Symphony Concert Association, 1905–1918
Authors: Koehler Jonathan
Published: April 2008

Ifhigh culture, asTheodorAdornoonce proposed, promises a reality that does not exist, why, at the fin de siècle, did it hold such great attraction for Central Europe's populist politicians who were most attuned to the realities of everyday life? The answer, at least for imperial Austria, is that those politicians believed high culture to possess an integrative social function, which forced them to reconcile notions of “high” culture with “mass” culture. This was particularly true in Vienna, where the city's public performance venues for art, music, stage theater, and visual art stood as monuments to the values that the liberal middle classes had enshrined in the 1867 Constitution. A literate knowledge of this cultural system—its canon of symphonic music; the literature of tragedy, drama, and farce; and classical and contemporary genres of painting—was essential for civic participation in an era of liberal political and cultural hegemony. This article examines one cultural association that attempted to exploit the interaction between German high culture and two spheres, which are commonly thought to stand at odds with elite, high culture: popular culture and mass politics. Rather than a simple, cultural divide, this relationship created a contested “terrain of political and social conflict” in the decades preceding World War I. This terrain was of enormous consequence for Viennese of every social class.
N3Logic: A logical framework for the World Wide Web
Authors: BERNERS-LEE TIM , CONNOLLY DAN , KAGAL LALANA , SCHARF YOSI , HENDLER JIM
Published: April 2008

The Semantic Web drives toward the use of the Web for interacting with logically interconnected data. Through knowledge models such as Resource Description Framework (RDF), the Semantic Web provides a unifying representation of richly structured data. Adding logic to the Web implies the use of rules to make inferences, choose courses of action, and answer questions. This logic must be powerful enough to describe complex properties of objects but not so powerful that agents can be tricked by being asked to consider a paradox. The Web has several characteristics that can lead to problems when existing logics are used, in particular, the inconsistencies that inevitably arise due to the openness of the Web, where anyone can assert anything. N3Logic is a logic that allows rules to be expressed in a Web environment. It extends RDF with syntax for nested graphs and quantified variables and with predicates for implication and accessing resources on the Web, and functions including cryptographic, string, math. The main goal of N3Logic is to be a minimal extension to the RDF data model such that the same language can be used for logic and data. In this paper, we describe N3Logic and illustrate through examples why it is an appropriate logic for the Web.
Introduction to the Special Issue on Logic Programming and the Web
Authors: MARCHIORI MASSIMO
Published: April 2008

The World Wide Web is nowadays the most famous and widespread information system. Its success is witnessed by its enormous size and rate of growth: however, the same success of the Web has brought to a situation where more sophisticated techniques are urgently needed to properly handle this mass of information. In this sense, the more ambitious plan for an evolution of a Web is the so called Semantic Web, envisioned by the inventor of the Web itself, Tim Berners-Lee. In this architectural vision, there is the need for further layers of semantics, properly enriching the data that now overflow the classic Web: ontologies, rules, logic, proofs, trust are all ingredients of this ambitious picture. Given these premises, it should not come as a surprise the fact that this evolution is bringing the Web closer and closer to another field, that since quite some time has been facing similar problems of logical organization of knowledge: logic programming. Early examples, like the Metalog system in the World Wide Web Consortium (W3C), had shown that connecting logic programming and the Semantic Web was quite a natural and fruitful step: and in fact, the burst of research in Semantic Web developments has eventually started to touch, connect and reinterprete many topics that were and are mainstream of the logic programming area. We feel this is a necessary progression, as the Semantic Web, and more generally the Web of the future, has a lot to learn from research in the logic programming area. And, conversely, in these new scenarios there are lot of new applied problems that can be challenging and rewarding from a logic programming perspective. This calls for a tighter interaction between the Web and logic programming, which was the reason to motivate this special issue as well: gathering together a selection of the best contributions that could showcase the potential of the cross-breeding.
Family Violence, Immigration Law, and the Rorschach 1Adapted from a paper in the symposium “Trauma and the Rorschach” at the XVII International Rorschach Congress, Rome, Italy, September 13, 2002.
Authors: Evans F. Barton
Published: April 2008

Dans cet article, nous examinons le cas de Mme A., une citoyenne américaine d'origine pakistanaise dont le mari, selon les termes de son visa, devait retourner pour deux ans au Pakistan. Mme A. demandait aux Services de l'Immigration d'accorder une dérogation à son mari afin qu'il reste aux États-Unis, au motif qu'elle ne supporterait pas d'être séparée de lui pendant deux ans. Nous présentons brièvement les principes de l'évaluation psychologique dans les procédures d'immigration, un domaine nouveau d'expertise psycholégale, ainsi qu'une biographie de Mme A. Celle-ci met en évidence les dangers qu'elle encourrerait au Pakistan et les multiples violences dont elle a été victime. Nous présentons l'examen psychologique de Mme A. en insistant sur l'apport du Rorschach (SI) dans l'évaluation de l'impact et de l'étendue de son traumatisme psychologique. Nous mettons en lumière la pertinence du Rorschach dans l'évaluation du traumatisme dans des contextes psycholégaux.
Comparison Between the Original Rorschach Plates and the Parisi-Pes Parallel Series in Argentina
Authors: Passalacqua Alicia Martha , Pestana Lelia Sandra
Published: April 2008

Le texte présenté est la synthèse serrée d'une étude menée par le Département du Rorschach de la Faculté de Psychologie de l'université de Buenos Aires et d'autres universités en Argentine. Nous y soulignons l'importance de valider une série parallèle de planches de Rorschach dans notre environnement, afin de disposer d'une série alternative en cas de besoin. Cette nécessité vient de la grande diffusion de la technique dans les champs de la psychologie communautaire qui pourrait produire un effet d'apprentissage et gêner l'utilisation psychodiagnostique de cet instrument.

Le Rorschach lui-même s'est montré un instrument d'évaluation particulièrement pertinent et valide, ce qui en a rendu l'usage indispensable dans différents secteurs de la pratique, tels qu'en psychologie légale, psychologie du travail, clinique et en éducation. La série parallèle de Parisi-Pes pourrait constituer une alternative, et il est donc nécessaire d'en établir l'équivalence sur la population locale.

Notre analyse s'est centrée sur les indicateurs du fonctionnement du moi (adaptation, jugement et testing de la réalité), en raison de leur importance dans le diagnostic différentiel, ainsi que sur les réponses réputées banales en Italie. Nous avons aussi mené une étude pilote sur le fonctionnement affectif et l'influence du sexe.
Are the Relationships Between NEO PI-R and Rorschach Markers of Openness to Experience Dependent on the Patient’s Test-Taking Attitude?
Authors: Petot Jean-Michel
Published: April 2008

The low correlations reported between self-report measures and the Rorschach raise questions about the validity of both kinds of instruments. Meyer (1996) suggested that these low correlations are an artefact, due to the failure to control response style. Correlations would be high and positive when subjects have the same response style on both methods, and high and negative when they have divergent response styles. But response style is assessed according to criteria strongly connected with distress, and the enhancement of correlations may be tautologically limited to distress scales. The objective of this research is to verify whether the response style hypothesis applies to Openness to Experience, a dimension unrelated with distress. Correlations were computed between on the one hand Openness and Neuroticism, and on the second one several selected Rorschach variables. Analyses were conducted on the whole sample (n = 96) and on separate subgroups of patients with convergent (n = 29) or divergent (n = 22) test-taking attitude. The findings establish Openness is related to Rorschach low L, high blends, morbid responses, and combinatory special scores. They also establish that response style moderates correlations between Neuroticism and the Rorschach, but not between Openness and the Rorschach. These results seem to confirm the tautological nature of the present formulation of the response style hypothesis, but further refinement in the analysis of test-taking attitude could help reconsider things.
Correlation Between the Rorschach Test Coded and Interpreted According to the Comprehensive Exner System and the Eysenck Personality Inventory
Authors: De Carolis Antonella , Ferracuti Stefano
Published: April 2008

The relationships between the Rorschach test and the self-reported personality questionnaires are an important and unresolved issue in confirming structural and clinical hypotheses. In a sample of healthy volunteers (n = 47) we conducted a study to investigate the correlation between the Italian version of the Eysenck Personality Questionnaire (Eysenck Personality Inventory, EPI) and some selected Rorschach variables defined according to the Exner Comprehensive System. The results showed that the Extroversion Scale of the EPI corresponds with the calculated difference between the Human Movement responses and the Weighted Sum of the Color response (M-WSumC, r = –.42, p < .01), the Weighted Sum of Color responses (WSumC, r = .40, p < .01) as a single variable, and the Sum of Shading responses (SumShd, r = .29, p < .05), but had no relationship with the Human Movement responses. None of the hypothesized Rorschach variables showed a significant correlation with the Neuroticism scale of the EPI. Furthermore, the Psychoticism scale of the EPI was negatively correlated with the Rorschach index Zsum (r –.33, p < .05). Finally, the comparison between the subgroups defined by the Erlebnistypus categories showed that Rorschach Extratensive subjects scored higher on the Extroversion scale of the EPI than Introversive (Mann-Whitney U = 30.5, p < .01) or Ambitent subjects (Mann-Whitney U = 76, p < .01). These results indicate that Rorschach’s concept of Erlebnistypus as a holistic dimension and Eysenck’s construct of Extroversion-Introversion are sufficiently homogeneous for psychometric assessment, but the single determinants of Rorschach responses have no correspondence with the EPI scores.
Maternal Resilience and Chronic Depression in Mourning for a Child: A Preliminary Case-Based Analysis
Authors: de Tychey Claude , Dollander Marianne
Published: April 2008

This article reports a retrospective comparative study of 10 mothers whose loss of a child caused chronic major depression despite medication followed by psychotherapy. The mothers were compared to 10 other mothers who participated in a longitudinal study conducted over the time period between the occurrence of the tragedy and complete recovery. The mothers were compared on the basis of life-event data, a semidirective interview, and a projective inquiry using the Rorschach Test. Some important differences were found between the two groups of mothers, from the standpoint of the support offered by their therapist, the elaboration of guilt feelings following the loss, their ability to mentally represent the trauma as assessed by the Rorschach Test, and their capacity to disinvest the lost object. Two factors that were not considered at the beginning of the research seem to fulfill a crucial function from the preventive standpoint: (1) the possibility of offering mourning mothers psychological support in addition to medication immediately after the loss, and (2) the possibility for the mother of freeing herself from a strong oedipal link with the deceased child.
Cerebral Metabolism and Personality in Patients with Epilepsy of the Temporal Lobe
Authors: de Felipe-Oroquieta J. , Ortega F. , Maldonado A. , Pozo M. A. , Sola R. G.
Published: April 2008

Extratension and introversion are stable personality styles in adult subjects. Mental functioning of the former is especially influenced by the emotions and of the latter by ideation. The aim of the present work is to analyze, using positron emission tomography with [18F]fluorodeoxyglucose (18FDG-PET), possible differences in cerebral metabolism in patients with intractable temporal lobe epilepsy (TLE) in relation to different personality styles assessed with the Rorschach test.

Twenty-eight drug-resistant TLE patients with complex partial seizures were assessed by means of FDG-PET and the Rorschach test. According to location of the epileptogenic area in the dominant hemisphere and the personality style of the subject, a table of contingencies was drawn up (χ² and contingency coefficient). Finally, an analysis was made of the personality changes in patients that had received neurosurgical treatment.

The results show a clear differentiation with FDG-PET as regards location of the temporal lobe affected. In 80% of subjects personality style coincided with a cerebral metabolic pattern: introversives had predominant hypometabolism in the left hemisphere and extratensives in the right. The tendency toward introversion or extratension in ambitents showed this metabolic pattern only in 38% of subjects, with 54% presenting the opposite pattern. The Rorschach test was carried out for a second time after surgical temporal resection (n = 13), and it was observed that some patients maintained their personality style while others modified it.

These results suggest the existence of different hemispheric metabolic patterns in the personality styles assessed by the Rorschach test in TLE patients.
Comparative Approach to Separation Anxiety Using the Baby Bird Tale
Authors: Lighezzolo Joëlle , de Tychey Claude , Thiebaut Eric
Published: April 2008

Authors present a new tool: the baby bird tale, taken from Tales Test ( Royer, 1978 ), which can be used to diagnose separation anxiety disorder. They compared the responses of a control group of 120 children divided into three subgroups (4–6, 6–11, and 11–13 years of age), with the responses of a clinical group of 80 children suffering from separation anxiety disorder, matched for age, sex and parental socioeconomic status. Results show the discriminating value of the instrument and confirm the existence of an insecure attachment and of the inability to mentally elaborate separation anxiety among children from the clinical subgroup.
An integrated study of microstructural, geochemical, and seismic properties of the lithospheric mantle above the Kerguelen plume (Indian Ocean)
Authors: Bascou J. , Delpech G. , Vauchez A. , Moine B. N. , Cottin J. Y. , Barruol G.
Published: April 2008

Peridotite xenoliths brought up to the surface by the volcanism of the Kerguelen Islands represent a mantle that has been affected by a high degree of partial melting followed by intense melt percolation above the Kerguelen plume. These xenoliths are therefore particularly suitable to investigate effects of melt‐rock interaction on crystallographic fabrics (lattice‐preferred orientation (LPO)) of peridotite minerals and on the LPO‐induced seismic properties of peridotites above a mantle plume. We have studied a suite of 16 ultramafic samples representative of different degrees of partial melting and magma‐rock interaction among which the protogranular harzburgites are the least metasomatised xenoliths and dunites are the ultimate stage of metasomatism. Olivine LPO is characterized by high concentration of [010] axes perpendicular to the foliation and [100] axes close to the lineation or distributed in the foliation plane in harzburgites, whereas the high concentration of [100] axes is parallel to the lineation and [010] axes is perpendicular to the assumed foliation in dunites. Olivine LPO in harzburgites is interpreted as being due to a deformation regime in axial compression or transpression. The fabric strength of olivine decreases progressively from protogranular to poikilitic harzburgites and finally to dunites, for which it remains nevertheless significant (J index 3.8). Seismic properties calculated from LPO of minerals indicate that metasomatism at higher melt/rock ratio lowers the P wave velocities. The most significant difference between harzburgites and dunites corresponds to the distribution of S wave anisotropy. Harzburgites display the maximum of anisotropy within the foliation plane and the minimum of anisotropy perpendicular to the foliation plane, whereas the lowest anisotropy is parallel to the lineation for dunites. These modifications of seismic properties as a result of metasomatic processes may induce seismic heterogeneities in the mantle above the Kerguelen plume. In addition, assuming a lithospheric mantle primarily harzburgitic and structured with a horizontal foliation, the seismic properties calculated for the Kerguelen xenoliths reconcile the rather high anisotropy evidenced by the horizontally propagating surface waves with the apparent isotropy revealed by the absence of splitting of vertically propagating teleseismic SKS waves recorded by the GEOSCOPE Kerguelen station.
Simulated heat storage in a perennially ice‐covered high Arctic lake: Sensitivity to climate change
Authors: Vincent Aaron C. , Mueller Derek R. , Vincent Warwick F.
Published: April 2008

Perennially ice‐covered, meromictic lakes occur along the northern coast of Ellesmere Island in the Canadian high Arctic and have distinctive conductivity and temperature profiles. They are salinity stratified and have deep thermal maxima that persist throughout the year at temperatures up to 60°C above the winter minimum in the overlying atmosphere. Heat transfer in one of these lakes (Lake A, latitude 83.0°N, longitude 75.4°W) was simulated using a high spatial resolution model based on a one‐dimensional heat diffusion and radiative transfer equation, which was solved through numerical integration. Boundary conditions were forced using climate data from an automated weather station installed next to the lake. There was a good fit between simulated and observed water column temperatures, including the midwater temperature maximum of 8.5°C, after 63 years of heating (RMSE = 0.10°C). This suggests that Lake A became ice‐free in the 1940s, a known period of intense warming of the circumpolar Arctic. The model was sensitive to forcing by photosynthetically active radiation (PAR, 400–700 nm), in addition to optically related parameters such as surface reflectance, snow and ice cover, and the PAR diffuse attenuation coefficient. The unusual thermal structure is affected by stratified layers of pigmented microbial communities, which enhance the absorption of solar radiation. Simulation of ice‐free summers revealed that the lake's thermal profile would lose its characteristic shape over several decades and that ongoing climate change could reduce the thermal maximum from 8.5° to 4°C within 50 years.
A comparison of infrasound signals refracted from stratospheric and thermospheric altitudes
Authors: Whitaker Rodney W. , Mutschlecner J. Paul
Published: April 2008

Over the last several years, a large number of ground‐based infrasound arrays have been established for explosion monitoring as part of the International Monitoring System of the Comprehensive Nuclear Test Ban Treaty Organization. Results from these arrays have become valuable in understanding long‐range infrasound propagation in the atmosphere and complement earlier data. Two types of signals are often observed for a given source: those refracted at stratospheric heights and at thermospheric heights. In this contribution we compare several characteristics of these two signal types including observed pressure amplitude, average travel velocity, bearing, and signal duration. For this study we use archival data from atmospheric nuclear explosions, high explosive chemical explosions on the surface, earthquakes with previously detected stratospheric signals, and earthquakes for which stratospheric signals were not detected. We show that the combination of stratospheric and thermospheric signals may provide independent estimates of wind propagation conditions and source characteristics. The observations of both signal types may increase the confidence level of an infrasound signal detection.
Aerodynamic roughness lengths over movable beds: Comparison of wind tunnel and field data
Authors: Sherman Douglas J. , Farrell Eugene J.
Published: April 2008

We evaluate the increase in apparent roughness length during aeolian saltation. Using a data set comprising 291 wind profiles measured in wind tunnels or in the field, we tested the Charnock (1955), modified Charnock (Sherman, 1992), and Raupach (1991) relationships for the entire data set and for segregated wind tunnel and field data sets. We assessed the abilities of the models to predict enhanced roughness and investigated scaling differences between wind tunnels and field environments. For the entire data set, the Charnock relationship worked best, with an r2 of 0.25. For the segregated data sets, the Charnock relationship also worked best, with an average r2 of 0.675, as opposed to 0.66 for the modified Charnock and 0.61 for the Raupach model. For conditions with shear velocity ≤1.0 ms−1, the comparable, average values of r2 are 0.54, 0.625, and 0.645, respectively. There was an order of magnitude difference in the roughness length responses for wind tunnel and field data for each model evaluated, convincing evidence of a fundamental scaling constraint in the wind tunnel data. The scaling differences are attributed to conceptual and bias errors that include the use of the law of the wall versus the wake‐defect law or differences in turbulence characteristics, especially regarding the role of large coherent structures. Raupach's (1991) A was found to be an extremely volatile constant, making the modified Charnock relationship most suitable for predicting aerodynamic roughness lengths over movable sand beds.
Focal waveforms for various source waveforms driving a prolate‐spheroidal impulse radiating antenna (IRA)
Authors: Altunc Serhat , Baum Carl E. , Christodoulou Christos G. , Schamiloglu Edl , Buchenauer C. Jerald
Published: April 2008

Impulse radiating antennas (IRAs) are designed to radiate very fast pulses in a narrow beam with low dispersion and high field amplitude. For this reason they have been used in a variety of applications. IRAs have been developed for use in the transient far‐field region using parabolic reflectors. However, in this paper we focus in the near field region and develop the field waveform at the second focus of a prolate‐spheroidal IRA. Certain skin cancers can be killed by the application of a high‐amplitude electric field pulse. This can be accomplished by either inserting electrodes near the skin cancer or by applying fast, high‐electric field pulses without direct contact. We investigate a new manifestation of an IRA, in which we use a prolate spheroid as a reflector instead of a parabolic reflector and focus in the near‐field region instead of the far‐field region. This technique minimizes skin damage associated with inserting electrodes near the tumor. Analytical and experimental behaviors for the focal waveforms of two and four‐feed arm prolate‐spheroidal IRAs are explored. With appropriate choice of the driving waveform we maximize the impulse field at the second focus. The focal waveform of a prolate‐spheroidal IRA has been explained theoretically and verified experimentally.
Impact of stratospheric ozone hole recovery on Antarctic climate
Authors: Perlwitz Judith , Pawson Steven , Fogt Ryan L. , Nielsen J. Eric , Neff William D.
Published: April 2008

Model experiments have revealed that stratospheric polar ozone depletion and anthropogenic increase of greenhouse gases (GHG) have both contributed to the observed increase of summertime tropospheric westerlies in the Southern Hemisphere (SH) with the ozone influence dominating. As the stratospheric halogen loading decreases in the future, ozone is expected to return to higher values, with the disappearance of the Antarctic ozone hole. The impact of this ozone recovery on SH climate is investigated using 21st century simulations with a chemistry climate model (CCM). The model response to the ozone recovery by 2100 shows that tropospheric circulation changes during austral summer caused by ozone depletion between 1970 and 2000 almost reverse, despite increasing GHG concentrations. Comparison of the CCM results with multi‐model scenario experiments from the Fourth Assessment Report (AR4) by the Intergovernmental Panel on Climate Change (IPCC) emphasize the importance of stratospheric ozone recovery for Antarctic climate.
Characterization of MJO‐related upper tropospheric hydrological processes using MLS
Authors: Schwartz Michael J. , Waliser Duane E. , Tian Baijun , Wu Dong L. , Jiang Jonathan H. , Read William G.
Published: April 2008

This study quantifies Madden‐Julian Oscillation (MJO)‐related hydrological variability in the upper troposphere/lower stratosphere (UT/LS) using Aura Microwave Limb Sounder (MLS) cloud ice water content (IWC) and water vapor (H2O). In a composite of six boreal‐winter MJO events, the UT/LS IWC anomaly is strongly positively correlated with the convection (TRMM rainfall) anomaly. IWC anomalies range from ±2 mg/m3 at 215 hPa to ±0.08 mg/m3 at 100 hPa. The UT/LS H2O anomaly has an eastward‐tilting structure similar to the previous‐documented temperature structure, but the H2O maximum lags the temperature maximum by about a week. The H2O anomaly is positively correlated with the convection anomaly in the UT (261 hPa) and LS (68 hPa) but negatively correlated with the convection anomaly near the tropopause (100 hPa). This analysis provides a multi‐parameter construct useful in validating and improving the parameterization of convection, clouds and cloud microphysics in MJO modeling.
Methane emission from rice cultivation: Geographic and seasonal distribution of cultivated areas and emissions
Authors: Matthews Elaine , Fung Inez , Lerner Jean
Published: April 2008

We present high‐resolution global data bases on the geographic and seasonal distribution of rice cultivation and associated methane emission. The data bases were developed by integrating extensive and eclectic information on the cultivation of rice in all 103 rice‐producing countries of the world. The geographic distribution of rice‐growing locations was developed by combining a 1° resolution land‐use data base identifying rice‐farming regimes, a 1° resolution data base of countries of the world, and country statistics on areas of annual rice harvest available from the U. N. Food and Agriculture Organization. The seasonal distribution of cultivated rice areas was derived via the integration of the data base on rice‐growing locations with information on cultivation activities and rice cropping practices for each rice‐producing country of the world; this information included seasonal rice‐cropping calendars for individual countries and statistics or estimates of the seasonal distribution of annual harvest areas in each crop cycle. Since the causes of the variability in methane fluxes from flooded rice fields have yet to be quantified, we did not attempt a new estimate of the role of rice cultivation in the global emission of methane. We evaluate, instead, the temporal and spatial distribution of emissions from a hypothetical annual source of 100 Tg methane. In 1984, 1475 × 109m2 of rice was harvested in 103 countries. Although rice cultivation extends from about 50°N to 50°S, 48% of the harvest area is confined to a narrow subtropical zone from 30°N to 20°N, while another 35% is harvested in the 10° zones directly to the north and south. Globally, about 60% of the harvested rice area is managed under a triple rice crop system, ∼15% is double cropped, and 25% is harvested from fields planted for rice once a year. In China and India, which together account for 52% of the world's harvest area, rice is harvested predominantly under a triple‐crop system. These patterns suggest that much of the potential for multiple rice cropping is currently exploited. In this analysis, methane emission is proportional to the area and duration of each harvest so that the seasonal, zonal and country patterns of annual methane emission mimic the distribution of rice‐harvest areas. Although rice is grown throughout the year, the close coupling of rice cultivation with climate results in the concentration of about 55% of the annual methane emission into four months from July through October and almost half the total emission in latitudes between 30°N and 20°N.
Microscopic circular polarizabilities (rotabilities) and the macroscopic properties of chiral media
Authors: Varadan Vasundara V. , Lakhtakia Akhlesh , Varadan Vijay K.
Published: April 2008

The concepts of canonical sources and canonical circular polarizabilities, which are referred to as “rotabilities” in this paper, appropriate for a chiral medium are used to describe circularly polarized fields in a medium containing a distribution of chiral (handed) particles. Due to the introduction of different rotabilities for right and left handed particles, we avoid mode conversion between left and right circularly polarized fields at the microscopic level which is also absent at the macroscopic level in an infinite homogeneous chiral medium. The transition from the microscopic to the macroscopic picture is hence smooth and involves just an ensemble average of the microscopic fields and the introduction of macroscopic constitutive equations, but does not involve the use of any extinction theorems. Extinction theorems are needed in other models that permit mode conversion in the microscopic picture but not in the macroscopic medium. Explicit relations are obtained between macroscopic material properties and microscopic polarizabilities in the long wavelength limit. These are similar to the Clausius‐Mossotti relations between the dielectric permittivity and the electric polarizability, but are not a trivial generalization for chiral media.
Transient analysis of vector potential in three‐dimensional space by spatial network
Authors: Yoshida Norinobu
Published: April 2008

Recently, for many kinds of complex engineering problems, numerical analysis methods have become very useful with the remarkable development of the digital computer, especially the super computer. I have recently proposed a new method for the vector analysis of the electromagnetic field, which is called as the spatial network method (SNM). This method is based on both the three‐dimensional spatial lattice network of Maxwell's equations and the formulation by the Bergeron method in the time domain. For the analysis of some problems involving sources such as currents or charges it is known that the formulation by the vector potential is effective. This paper describes that the SNM can be easily applied to the vector potential fields with the gauge condition in that the divergence of the vector potential is zero. The formulation is performed in the same spatial lattice network as that for Maxwell's equation, and both the magnetic and electric vector potential variables are introduced. Therefore the proposed method succeeds the advantages of SNM for analyses of electromagnetic fields. For examining the fundamental characteristics and the validity of the formulation the electromagnetic field distributions around a line current and a small loop current are computed.
Higher‐order mode field distribution in asymmetric transverse electromagnetic cells
Authors: Wilson P. F.
Published: April 2008

The higher‐order modes in asymmetric transverse electromagnetic (TEM) cells are considered; in particular, field expressions are developed and catalogued. These may be used to examine scattering and reflection from test objects and discontinuities. The results are applied to the termination reflection in a large tapered cell. Experiment and theory agree well and aid in understanding perturbations to the desired TEM mode field distribution.
Packets of cyclotron waves induced by electron beam injection from the space shuttle 2. Nonlinear theory
Authors: Mourenas D. , Béghin C.
Published: April 2008

During the Spacelab 1 space shuttle mission, electron beam injection in the ionosphere produced a variety of radio waves. The most unusual kind of spectrum consisted of packets of cyclotron waves occurring at successive harmonics of a frequency F0 close to the upper hybrid ƒuh. A linear treatment of the generation mechanism has been proposed in a companion paper [Mourenas and Béghin, this issue]. It was shown that the emissions consist of the well‐known electronic Bernstein modes, which are excited by an interaction between the neutralization return current and the ambient ionospheric plasma. The observed amplitude modulation of the cyclotron emissions around the fundamental wave at F0 = nƒce closest to ƒuh has been explained in the frame of a model which shows that some of the generated waves packets can escort the space‐borne receiver. However, the observation of successive harmonic packets around pF0 remained to be interpreted. To this end, a two‐dimensional single‐wave model of the nonlinear interaction between a finite size ring beam and an infinite homogeneous magnetized plasma is presented. A system of scaled equations is developed and solved analytically for the initial evolution and shows a good agreement with the linear theory. The system is then solved numerically. The solution shows that the single F0 wave considered grows exponentially at the linear growth rate; then the wave potential saturates due to beam electron trapping, producing a power law spectrum of the higher pF0 harmonics of the electric field very similar to what was observed experimentally.
Electromagnetic fields of a nonprecessing and processing, spinning, permanent magnet, conducting sphere
Authors: Mueller R. S.
Published: April 2008

The electromagnetic fields inside and outside a steadily rotating, magnetized, conducting sphere are determined for the cases of nonprecession and precession. In both cases the spin rotational axis is aligned with the magnetic axis of the sphere. The field expressions are those measured in the laboratory reference frame. For a nonprecessing sphere the magnetic fields are identical to the fields of a stationary sphere, but in addition there is an induced induction of order υ2/c2 whose lines of force radiate in loops above and below the equator. The electric and magnetic induction field expressions were derived in the laboratory frame when the sphere precesses in an external magnetic field. They can be divided into static and dynamic parts. The amplitudes of these parts were plotted as functions of the angle of inclination of the polar axis. The dynamic parts are circularly and elliptically polarized. The pivot point of the precessing sphere was chosen off center. The only two stable positions are at θ = 0° and 180° for a center pivot.
Fading reduction in microwave IOS links using antenna beam tilting techniques
Authors: Prasad M. V. S. N. , Dutta H. N. , Sarkar S. K. , Reddy B. M.
Published: April 2008

Microwave field strength measurements are conducted on a round the clock basis on an operational communication link in northern India. In winter and premonsoon months, nighttime signal exhibits deep fades with fall in median signal level. The investigations revealed that nighttime fading is due to the refraction of signal from ground‐based layers. To minimise the amount of energy refracted by the ground‐based layers, the antennae were tilted upward. The tilting of antennae has decreased the fade depths, and an improvement in the performance of the link is obtained.
An algorithm for the removal of radio frequency interference in ionospheric backscatter sounding
Authors: Earl G. F.
Published: April 2008

In common with all wideband ionospheric sounding systems the backscatter technique is susceptible to contamination by radio frequency interference. The eradication of such interference is imperative in systems required to automatically interrogate the backscatter sounder data base. This paper presents the results of the development of an algorithm designed for that purpose. The philosophy guiding the design is presented, together with the results of a computer simulation designed to simultaneously validate the proposed approach and derive an appropriate threshold. Details of the implementation are provided together with data demonstrating the effectiveness. The algorithm is capable of being implemented in any backscatter sounder system featuring an adequate digital signal processing capability.