bluuebunny/crossref_metadata_2025 huggingface dataset:
A simple and general change‐point identifier
Authors: Riffenburgh R. H. , Cummins K. M.
Published: December 2005

In a not‐necessarily‐stationary time‐series, a Moving F statistic can identify points of change in the nature of the series model (the estimate of the underlying data‐generating process), in its parameters, in residual variability, or in any combination of these. In addition, it can uncover changes masked by a reduction in residual variability. Patterns in the forces giving rise to the data may often be perceived. To form the Moving F, a theory of the process or a regression method on a baseline sample estimates the series model and the residual mean square about it is calculated. This series model is extended past the baseline with residuals assumed to be normally distributed. The Moving F is calculated as the moving average of squared deviations about the series model in ratio to the baseline mean square. The Moving F crossing the critical F identifies a change in the series model, i.e. signals its presence and location. In our experience, this Moving F method is easier to use than other commonly employed change‐point identifiers (CUSUM, EWMA, data‐based bandwidth selection, MCMC) and has been found to work in several situations where some other identifiers fail. (MCMC is more general, but requires advanced statistical ability.) Examples given are monitored prostate specific antigen in a post‐treatment prostate cancer patient and detection of Harold Shipman's medical murders. Moving F is ‘simple and general’ in the sense of both simultaneously; we have not found another relatively simple method to be as general. Published in 2005 by John Wiley & Sons, Ltd.
ROC analysis for markers with mass at zero
Authors: Schisterman Enrique F. , Reiser Benjamin , Faraggi David
Published: December 2005

The receiver operating characteristic (ROC) curve and in particular the area under the curve (AUC) is commonly used to examine the discriminatory ability of diagnostic markers. Certain markers while basically continuous and non‐negative have a positive probability mass (spike) at the value zero. We discuss a flexible modelling approach to such data and contrast it with the standard non‐parametric approach. We show how the modelling approach can be extended to take account of the effect of explanatory variables. We motivate this problem and illustrate the modelling approach using data on the coronary calcium score, measured by electron beam tomography, which is a marker for atherosclerosis. Copyright © 2005 John Wiley & Sons, Ltd.
A modified test for small‐study effects in meta‐analyses of controlled trials with binary endpoints
Authors: Harbord Roger M. , Egger Matthias , Sterne Jonathan A. C.
Published: December 2005

Publication bias and related bias in meta‐analysis is often examined by visually checking for asymmetry in funnel plots of treatment effect against its standard error. Formal statistical tests of funnel plot asymmetry have been proposed, but when applied to binary outcome data these can give false‐positive rates that are higher than the nominal level in some situations (large treatment effects, or few events per trial, or all trials of similar sizes). We develop a modified linear regression test for funnel plot asymmetry based on the efficient score and its variance, Fisher's information. The performance of this test is compared to the other proposed tests in simulation analyses based on the characteristics of published controlled trials. When there is little or no between‐trial heterogeneity, this modified test has a false‐positive rate close to the nominal level while maintaining similar power to the original linear regression test (‘Egger’ test). When the degree of between‐trial heterogeneity is large, none of the tests that have been proposed has uniformly good properties. Copyright © 2005 John Wiley & Sons, Ltd.
A Bayesian determination of threshold for identifying differentially expressed genes in microarray experiments
Authors: Chen Jie , Sarkar Sanat K.
Published: December 2005

The original definitions of false discovery rate (FDR) and false non‐discovery rate (FNR) can be understood as the frequentist risks of false rejections and false non‐rejections, respectively, conditional on the unknown parameter, while the Bayesian posterior FDR and posterior FNR are conditioned on the data. From a Bayesian point of view, it seems natural to take into account the uncertainties in both the parameter and the data. In this spirit, we propose averaging out the frequentist risks of false rejections and false non‐rejections with respect to some prior distribution of the parameters to obtain the average FDR (AFDR) and average FNR (AFNR), respectively. A linear combination of the AFDR and AFNR, called the average Bayes error rate (ABER), is considered as an overall risk. Some useful formulas for the AFDR, AFNR and ABER are developed for normal samples with hierarchical mixture priors. The idea of finding threshold values by minimizing the ABER or controlling the AFDR is illustrated using a gene expression data set. Simulation studies show that the proposed approaches are more powerful and robust than the widely used FDR method. Copyright © 2005 John Wiley & Sons, Ltd.
Repeated events survival models: the conditional frailty model
Authors: Box‐Steffensmeier Janet M. , De Boef Suzanna
Published: December 2005

Repeated events processes are ubiquitous across a great range of important health, medical, and public policy applications, but models for these processes have serious limitations. Alternative estimators often produce different inferences concerning treatment effects due to bias and inefficiency. We recommend a robust strategy for the estimation of effects in medical treatments, social conditions, individual behaviours, and public policy programs in repeated events survival models under three common conditions: heterogeneity across individuals, dependence across the number of events, and both heterogeneity and event dependence. We compare several models for analysing recurrent event data that exhibit both heterogeneity and event dependence. The conditional frailty model best accounts for the various conditions of heterogeneity and event dependence by using a frailty term, stratification, and gap time formulation of the risk set. We examine the performance of recurrent event models that are commonly used in applied work using Monte Carlo simulations, and apply the findings to data on chronic granulomatous disease and cystic fibrosis. Copyright © 2005 John Wiley & Sons, Ltd.
Cumulative effects of air pollution on public health
Authors: Xia Yingcun , Tong Howell
Published: December 2005

Cumulative effect is an important way through which the pollutants affect public health. However, few existing dynamical models are well enough understood and documented to detect or quantify the cumulative effects and to answer pertinent questions posed by the World Health Organization (WHO): ‘Is there a threshold below which no effects of the pollutants on health are expected to occur in all people?’ and ‘What averaging period (time pattern) is the most relevant from the point of view of health?’. Using a new semi‐parametric time series modelling approach, which incorporates non‐linearity and latent cumulative variables, we show that the cumulative effects on health due to continual exposure to environmental pollutants can be very serious even at levels below the national ambient air quality standards of America (NAAQS). The situation is especially worrying for chronic sufferers. Our study suggests that different pollutants may require different cumulative periods (on average) to impact on health but they share a similar functional form in respect of their impact. We also suggest some possible revision of the ambient air quality standards. Copyright © 2005 John Wiley & Sons, Ltd.
The analysis of contingency tables with ordinal data: an application to monitoring antibiotic resistance
Authors: Bonetto C. , Giannerini S. , Giovagnoli A.
Published: December 2005

Rationalization of antibiotic therapy in the management of infectious diseases is helped by a knowledge of the patterns of sensitivity and resistance of bacteria to antibiotics and their possible changes both in time and from one hospital unit to another. In this paper we present the results regarding the sensitivities of several groups of bacteria and different Units of the S.Orsola‐Malpighi Hospital of Bologna in the period 1995–1997. We apply recent methods of analysis of ordinal contingency tables that rely on stochastic ordering of the rows to test the assumption that a decrease (or increase) in sensitivity of bacteria to specific antibiotics has taken place against the alternative that no such thing has happened. In most cases the results seem to indicate an increase in sensitivity rather than what was expected, namely the opposite. Copyright © 2005 John Wiley & Sons, Ltd.
Survival analysis using auxiliary variables via non‐parametric multiple imputation
Authors: Hsu Chiu‐Hsieh , Taylor Jeremy M. G. , Murray Susan , Commenges Daniel
Published: December 2005

We develop an approach, based on multiple imputation, that estimates the marginal survival distribution in survival analysis using auxiliary variables to recover information for censored observations. To conduct the imputation, we use two working survival models to define a nearest neighbour imputing risk set. One model is for the event times and the other for the censoring times. Based on the imputing risk set, two non‐parametric multiple imputation methods are considered: risk set imputation, and Kaplan–Meier imputation. For both methods a future event or censoring time is imputed for each censored observation. With a categorical auxiliary variable, we show that with a large number of imputes the estimates from the Kaplan–Meier imputation method correspond to the weighted Kaplan–Meier estimator. We also show that the Kaplan–Meier imputation method is robust to mis‐specification of either one of the two working models. In a simulation study with time independent and time‐dependent auxiliary variables, we compare the multiple imputation approaches with an inverse probability of censoring weighted method. We show that all approaches can reduce bias due to dependent censoring and improve the efficiency. We apply the approaches to AIDS clinical trial data comparing ZDV and placebo, in which CD4 count is the time‐dependent auxiliary variable. Copyright © 2005 John Wiley & Sons, Ltd.
Bias reduction in effectiveness analyses of longitudinal ordinal doses with a mixed‐effects propensity adjustment
Authors: Leon Andrew C. , Hedeker Donald , Teres Jedediah J.
Published: December 2005

A mixed‐effects propensity adjustment is described that can reduce bias in longitudinal studies involving non‐equivalent comparison groups. There are two stages in this data analytic strategy. First, a model of propensity for treatment intensity examines variables that distinguish among subjects who receive various ordered doses of treatment across time using mixed‐effects ordinal logistic regression. Second, the effectiveness model examines multiple times until recurrence to compare the ordered doses using a mixed‐effects grouped‐time survival model. Effectiveness analyses are initially stratified by propensity quintile. Then the quintile‐specific results are pooled, assuming that there is not a propensity × treatment interaction. A Monte Carlo simulation study compares bias reduction in fully specified propensity model relative to misspecified models. In addition, type I error rate and statistical power are examined. The approach is illustrated by applying it to a longitudinal, observational study of maintenance treatment of major depression. Copyright © 2005 John Wiley & Sons, Ltd.
Maillard reaction product‐rich food impair cell proliferation and induce cell death in vitro
Authors: Bartling Babett , Rehbein Grit , Somoza Veronika , Silber Rolf‐Edgar , Simm Andreas
Published: December 2005

Maillard reaction products (MRPs) and advanced glycation end‐products (AGEs) correspond to modified protein derivatives that are initially generated by non‐enzymatic glycation between amino acids and reducing sugars in heat‐treated foods and in vivo, respectively. Because lung tissue highly expresses the receptor for advanced glycation end‐products (RAGE), we studied the impact of MRP/AGE‐rich foods like bread crust (BC) and coffee extract (CE) on the proliferation and cell death induction using lung epithelial (H358) cells. Here, we showed that CE impairs the proliferation and viability of H358 cells at much higher extent than BC does. Particularly cell death induced by CE showed a concentration‐dependent shift from apoptotic to necrotic features as estimated by caspase activation, phosphatidylserine exposure, leakage of the outer membrane, mitochondrial dysfunction and stress kinase activation. Moreover, CE at higher dose triggered the generation of reactive oxygen species thereby mediating caspase inhibition. Non‐toxic concentrations of both foods only impaired the proliferation associated with an increased amount of cells in the S/G2 phase of the cell cycle, which did not depend on the over‐expression of RAGE. From our data we conclude that MRP/AGE‐rich foods mediate antiproliferative effects at moderate concentrations that might be important in physiological conditions like cancer prevention but contributes to cell death at higher levels in vitro.
NFκB: cell survival or cell death?
Authors: Strozyk Elwira , Kulms Dagmar
Published: December 2005

The present review outlines that the different pathways and components that may influence NFκB, to convert it from an inhibitor of apoptosis into a promoter of apoptosis, are quite versatile. As a consequence inhibition of the NFκB as a global concept to fight cancer should be reconsidered, although of course it seems reasonable for many incidences. Conclusively, cancer therapy can not be generalized but requires individual treatment.
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Efficient Designs for Powering Microscale Devices with Nanoscale Biomolecular Motors
Authors: Lin Chih‐Ting , Kao Ming‐Tse , Kurabayashi Katsuo , Meyhöfer Edgar
Published: December 2005

Current MEMS and microfluidic designs require external power sources and actuators, which principally limit such technology. To overcome these limitations, we have developed a number of microfluidic systems into which we can seamlessly integrate a biomolecular motor, kinesin, that transports microtubules by extracting chemical energy from its aqueous working environment. Here we establish that our microfabricated structures, the self‐assembly of the bio‐derived transducer, and guided, unidirectional transport of microtubules are ideally suited to create engineered arrays for efficiently powering nano‐ and microscale devices.
Nanostructures of Sn and Their Enhanced, Shape‐Dependent Superconducting Properties
Authors: Hsu Yung‐Jung , Lu Shih‐Yuan , Lin Yi‐Feng
Published: December 2005

A noncatalytic and template‐free vapor transport process was developed to make possible simultaneous growth of single‐crystalline tin nanowires, nanosquares, nanodisks, and polycrystalline nanoparticles. The formation of such a rich variety of morphologies in a single growth experiment can be attributed to variations in the growth rate among different crystallographic planes when employing the vapor–solid growth mechanism. Structural characterization with high‐resolution transmission electron microscopy reveals a preferential growth direction of [100] in Sn nanowires, nanosquares, and nanodisks. Shape‐dependent superconducting properties are observed. These four types of Sn nanostructures all show typical diamagnetic behavior in magnetization measurements, with the three anisotropically shaped nanostructures (nanowires, nanosquares, and nanodisks) showing one order of magnitude enhancement in the working magnetic field ranges for superconductivity, compared to bulk Sn and Sn nanoparticles. The magnetic field range is broadest for nanowires, followed by nanodisks, nanosquares, and nanoparticles.
Golden face: Cultural reciprocity in the articulation of mainland Chinese social structure
Authors: Lewis Hugh M.
Published: December 2005

The informal Chinese system of “face,” or dynamic, open‐ended networks of reciprocal social relations and transactions, is at the core of the everyday construction of contemporary Chinese social realities. Implicit rules guiding behavior in these networks regulate social relations and provide a familial sense of symbolic order and behavioral purpose to the Chinese world. If one is to endeavor any long‐term venture in China, for whatever constructive purposes, one must eventually come to terms with and even learn to negotiate this system of face with whomever one deals. © 2006 Wiley Periodicals, Inc.
Life and times of a Danish entrepreneur: Lessons for today's Russian market
Authors: Holden Nigel
Published: December 2005

Harald Schou‐Kjeldsen first went to Russia as a young Danish diplomat from 1915 to 1919 and lived there again—there being, of course, Soviet Russia by that point— from 1922 to 1934. During this time, he ran various import‐export businesses and notably set up a button factory, employing at its peak some 350 workers. Schou‐Kjeldsen's life in the early Soviet Union provides a remarkable picture of how Stalinism stifled his business activities. Schou‐Kjeldsen, a resourceful entrepreneur in an adversarial business environment, has a special claim as a role model for foreign businesspeople operating in the not entirely dissimilar conditions of post‐Soviet Russia today. © 2006 Wiley Periodicals, Inc.
History and HRM in the central Asian states
Authors: Harry Wes
Published: December 2005

This article identifies the influence of history and economic, political, and social systems on human resource practices in five independent central Asian states, or “Stans,” that were formerly part of the Soviet Union. This is a fascinating region undergoing rapid change, not always smoothly, in an area of strategic importance to Asia and beyond. The period since independence has been a time of declining well‐being, especially in education, health care, and economic prosperity, for most of the people in the region, but there is hope that the future will be better. These rapid changes have influenced human resource practices, and the article highlights current and desired practices and provides foreign academics, businesspeople, and expatriates with knowledge about human resource management (HRM) issues in central Asia. © 2006 Wiley Periodicals, Inc.
Resources and equity ownership in IJVs in Turkey
Authors: Demirbag Mehmet , Weir David
Published: December 2005

Partners' resources are an important conceptual dimension of joint ventures (JVs), which may further expand our existing knowledge of determinants of equity control and partners' influence on JV strategy. This article builds on prior research by providing a comprehensive account of partners' resources in JVs and their impact on both ownership composition and partners' relative influence on JV strategy. Our findings provide relatively strong support to the resource‐based explanation of strategic alliances in emerging markets and indicate the further utility of a knowledge‐management perspective. © 2006 Wiley Periodicals, Inc.
Islam and business
Authors: Wilson Rodney
Published: December 2005

The underdevelopment of many of the Muslim economies along the Silk Road is often ascribed to the negative effects of Islam. Yet historically, the Muslim cities along the Road were thriving centers of commerce, and since the collapse of the Soviet Union, there appears to be a revival of business as central Asia is opened up to the global economy. Islam has its own distinctive code of business ethics, and the trust this fosters can lower transaction costs and increase management efficiency. There is no inherent conflict between Islam and capitalism; indeed, it is possible to identify the emergence of a distinctive Islamic type where capital accumulation is based on noninterest forms of financing. © 2006 Wiley Periodicals, Inc.
Islam and management: What can be learned?
Authors: Abuznaid Samir
Published: December 2005

Religion has a major impact on human behavior, social interactions, and social relations. This research article discusses the impact of Islam on managers' behavior. The impact is exerted from the five pillars of Islam: faith, prayer, alms, fasting, and pilgrimage. From the article, it is evident that such pillars have a direct effect on Moslems' behavior. Besides that, the article shows the significant impact of Allah supreme names on managers' behavior and style. Allah names have a direct interrelationship with management functions like planning, organizing, and directing. A Moslem manager, in fact, can use Allah supreme names as a guide to his management style and action. Finally, the article sheds light on major Islamic management principles and their effect on managers' behavior and perception. © 2006 Wiley Periodicals, Inc.
Guanxi and Wasta: A comparison
Authors: Hutchings Kate , Weir David
Published: December 2005

China has a business culture based on strong family connections secured in guanxi networks, while the Arab World's is based on strong family connections secured in wasta networks. This article compares guanxi, wasta, and the role of trust, family, and favors in underpinning these traditional modes of interpersonal connections and networks and considers the continued relevance of these practices as these regions of the world internationalize and modernize. The article provides insights for Western managers in their subsidiary operations in China and the Arab World. © 2006 Wiley Periodicals, Inc.
Possible indicators for biomass burning in a small Swedish city as studied by energy dispersive x‐ray fluorescence (EDXRF) spectrometry
Authors: Selin Lindgren E. , Henriksson D. , Lundin M. , Therning P. , Laursen J. , Pind N.
Published: December 2005

Biomass is increasingly used in energy plants of different size and sophistication in Sweden. Biomass is also available in Sweden owing to its large forest‐covered areas. Incineration of biomass in an environmentally friendly manner is one of the key issues in Swedish policy for sustainable development. Hence there is ongoing research on the effects of biomass burning on the air quality in Swedish cities. The relative contributions of anthropogenic sources to pollution in the urban environment are usually difficult to evaluate owing to the complexity of the ambient aerosol. In order to investigate the contribution of biomass incineration to air quality, energy‐dispersive x‐ray fluorescence (EDXRF) analysis was performed on aerosol particles sampled in the centre of the small city of Växjö. PM2.5 and PM2.5–10 fractions were sampled with the special aim of determining the contribution of biomass burning to particulate air pollution. In order to identify typical indicators for biomass burning, principle component analysis was performed on data on elemental contents and black carbon. Analysis suggests that the K/Zn ratio will be useful as an indicator for biomass incineration. Copyright © 2005 John Wiley & Sons, Ltd.
Are there any Early Fragments of the So-Called Gospel of Peter?
Authors: FOSTER PAUL
Published: December 2005

The first text in the Akhmîm codex discovered in Upper Egypt in 1886–87 was confidently identified as the Gospel of Peter, mentioned by Eusebius in his description of the activities of the second-century bishop Serapion. Although the Akhmîm text is dated palaeographically between the seventh and ninth centuries, it is seen as being a witness to a text that dates from at least as early as the second century. This position appeared to have been strengthened by the identification of a number of early papyrus fragments as belonging to the Gospel of Peter. This paper calls into question such identifications, and consequently suggests caution should be exercised before too quickly making the conclusion that the text from Akhmîm is to be identified with the second-century Gospel of Peter.
Decrees and Drachmas at Thessalonica: An Illegal Assembly in Jason's House (Acts 17.1–10a)
Authors: HARDIN JUSTIN K.
Published: December 2005

Those who have identified the specific charges of the judicial proceedings in Thessalonica according to Acts 17.6–9 have generally taken one of two routes. The traditional view is that Paul and Silas were accused of treason (maiestas). Just over three decades ago, however, E. A. Judge put forth an alternative hypothesis that the decrees of Caesar in Acts 17.7 referred to imperial laws against predicting the change of ruler. After challenging these two explanations, this essay puts forward a fresh proposal – that both the charges and the seizure of payment in this judicial episode relate to the imperial laws repressing Graeco-Roman voluntary associations.
Living Rewards for Dead Apostles: ‘Baptised for the Dead’ in 1 Corinthians 15.29
Authors: PATRICK JAMES E.
Published: December 2005

Baptism in the Corinthian church was an expression of allegiance to honour not only Christ but also the ‘patron’ apostle in whose testimony the convert had believed (1 Cor 1.12–17). Some apostles known to the Corinthians had died (cf. 15.6), yet their testimony lived on and bore fruit in Corinth, resulting in baptism for the honouring of the dead apostles. In the context of 15.20–34 Paul uses this practice to expose the hypocrisy of those who deny the resurrection and yet seek to honour apostles who depend on the resurrection for receiving honour, as do Christ and God the Father.
Galatians 2.20 in Context
Authors: SHAUF SCOTT
Published: December 2005

When interpreted in its context in the argument of Galatians, Gal 2.20 is an important part of Paul's discussion of justification by faith. It functions as a depiction of justification apart from any consideration of Jew or Gentile status. This conclusion is based on an examination of the flow of Gal 2.15–21, a consideration of 2.15–21 in its larger context, and a study of 2.20 itself. This role of Gal 2.20 has frequently been overlooked due to inherent difficulties in interpreting the passage and to specific features about the way scholars have interpreted the verse and the larger passage.
Paul's Allegory of the Two Covenants (Gal 4.21-31) in Light of First-Century Hellenistic Rhetoric and Jewish Hermeneutics
Authors: DI MATTEI STEVEN
Published: December 2005

Galatians 4.21-31 opens with a brief allusion to events recounted in Genesis 16-17, to which Paul aptly appends the following comment: ατινα εστιν αλληγορουμενα (4.24). Through a re-evaluation of the meaning of the verb αλληγορεω in the context of Hellenistic rhetoric and by setting Paul's own hermeneutic in the context of Jewish hermeneutical norms of the first century, this paper argues that Paul's allegory of the two covenants is more reflective of Jewish reading practices which sought to eschatologize the Torah, such as Paul's reading of Gen 16.1 through its haftarah, Isa 54.1, rather than Christian typology.
Stability of sea ice dynamics models: Viscous‐plastic rheology, replacement closure, and tensile cutoff
Authors: Pritchard Robert S.
Published: December 2005

To ensure model stability, the momentum balance, constitutive law, and hardening law must all be considered. In addition to a constitutive law that dissipates energy during all deformations, stability requires that infinitesimal perturbations to the model solutions decay. Their growth would imply that solutions are sensitive to small changes in initial conditions. Perturbation equations are introduced, linearized, and solved using normal modes. If a mode can grow, it can generate spurious motions from small initial perturbations. This stability analysis improves our understanding of the behavior of an isotropic viscous‐plastic model. The analysis shows that it has unstable opening and closing deformation states.
Quantitative interpretation of atmospheric carbon records over the last glacial termination
Authors: Köhler Peter , Fischer Hubertus , Munhoven Guy , Zeebe Richard E.
Published: December 2005

The glacial/interglacial rise in atmospheric pCO2 is one of the best known changes in paleoclimate research, yet the cause for it is still unknown. Forcing the coupled ocean‐atmosphere‐biosphere box model of the global carbon cycle BICYCLE with proxy data over the last glacial termination, we are able to quantitatively reproduce transient variations in pCO2 and its isotopic signatures (δ13C, Δ14C) observed in natural climate archives. The sensitivity of the Box model of the Isotopic Carbon cYCLE (BICYCLE) to high or low latitudinal changes is comparable to other multibox models or more complex ocean carbon cycle models, respectively. The processes considered here ranked by their contribution to the glacial/interglacial rise in pCO2 in decreasing order are: the rise in Southern Ocean vertical mixing rates (>30 ppmv), decreases in alkalinity and carbon inventories (>30 ppmv), the reduction of the biological pump (∼20 ppmv), the rise in ocean temperatures (15–20 ppmv), the resumption of ocean circulation (15–20 ppmv), and coral reef growth (<5 ppmv). The regrowth of the terrestrial biosphere, sea level rise and the increase in gas exchange through reduced sea ice cover operate in the opposite direction, decreasing pCO2 during Termination I by ∼30 ppmv. According to our model the sequence of events during Termination I might have been the following: a reduction of aeolian iron fertilization in the Southern Ocean together with a breakdown in Southern Ocean stratification, the latter caused by rapid sea ice retreat, trigger the onset of the pCO2 increase. After these events the reduced North Atlantic Deep Water (NADW) formation during the Heinrich 1 event and the subsequent resumption of ocean circulation at the beginning of the Bølling‐Allerød warm interval are the main processes determining the atmospheric carbon records in the subsequent time period of Termination I. We further deduce that a complete shutdown of the NADW formation during the Younger Dryas was very unlikely. Changes in ocean temperature and the terrestrial carbon storage are the dominant processes explaining atmospheric δ13C after the Bølling‐Allerød warm interval.
Sudden commencement event of 17 April 2002: Aspects of the geomagnetic response at low latitudes
Authors: Villante U. , Piersanti M. , Di Giuseppe P. , Vellante M. , Zhang T. L. , Magnes W.
Published: December 2005

An analysis of a sudden commencement (SC) manifestation reveals a significant contribution of the polar current system which influences the long‐term behavior of the H component at low‐latitude ground stations located in the subsolar sector. A transition between “morning” and “afternoon” characteristics of the geomagnetic response occurs at ≈1300 MLT. “Morning” events are characterized by a positive then negative variation (P/N) preceding the longer‐term variation and show a gentle latitudinal decrease of the asymptotic response; conversely, “afternoon” events, which are characterized by a N/P structure, show a steep latitudinal gradient. PPI and PRI structures are observed on opposite sides of the ≈1300 MLT boundary. The PPI consists of three dominant fluctuations at well‐defined frequencies and the small differences in the signal manifestation at nearby stations can be imputed to the occurrence of local resonance phenomena. Large‐amplitude pulsations appear soon after the SC occurrence at subauroral latitudes.
Amundsen Sea ice production and transport
Authors: Assmann Karen M. , Hellmer Hartmut H. , Jacobs Stanley S.
Published: December 2005

Drift and variability of sea ice in the Amundsen Sea are investigated with ice buoys deployed in March 2000 and a coupled ice‐ocean model. The Bremerhaven Regional Ice Ocean Simulations (BRIOS) model results are compared with in situ ocean, atmosphere, and sea ice measurements; satellite observations; and 8–19 months of buoy drift data. We identify a zone of coastal westward drift and a band of faster eastward drift, separated by a broad transition region characterized by variable ice motions. The model represents drift events at scales approaching its resolution but is limited at smaller scales and by deficiencies in the National Centers for Environmental Prediction forcing. Two thirds of the modeled ice production in the southern Amundsen moves westward near the coast, its transport modulated by meridional wind strength, damping sea ice formation in the eastern Ross Sea. Half of the ice exported from the Ross moves eastward into the northern Amundsen Sea, a net sea ice sink that also receives more than one third of the ice generated to its south. A low rate of exchange occurs with the Bellingshausen Sea, which must have a more independent ice regime. Snow ice formation resulting from high precipitation accounts for one quarter of the ice volume in the Amundsen Sea, aiding the formation of thick ice in a region with generally divergent ice drift. Freshwater extraction by sea ice formation is roughly balanced by precipitation and ice shelf melting, but a positive trend in the surface flux is consistent with an Amundsen source for reported freshening in the Ross Sea.
Suspended sand transport in surf zones
Authors: Kobayashi Nobuhisa , Zhao Haoyu , Tega Yukiko
Published: December 2005

Three tests were conducted in a wave flume to investigate time‐averaged suspended sediment transport processes under irregular breaking waves on equilibrium beaches consisting of fine sand. Free surface elevations were measured at ten locations for each test. Velocities and concentrations were measured in the vicinity of the bottom at 94 elevations along 17 vertical lines. The relations among the three turbulent velocity variances are found to be similar to those for the boundary layer flow. The vertical variation of the mean velocity, which causes offshore transport, is fitted by a parabolic profile fairly well. The vertical variation of the mean concentration is fitted by the exponential and power‐form distributions equally well. The ratio between the concentration standard deviation σC and the mean varies little vertically. The correlation coefficient γUC between the horizontal velocity and concentration, which results in onshore transport, is of the order of 0.1 and decreases upward linearly. The offshore and onshore transport rates of suspended sediment are estimated and expressed in terms of the suspended sediment volume per unit area. A time‐averaged numerical model is developed to predict as well as the mean and standard deviation of the free surface elevation and horizontal velocity. The bottom slope effect on the wave energy dissipation rate DB due to wave breaking is included in the model. The computation can be made well above the still water shoreline with no numerical difficulty. Reflected waves from the shoreline are estimated from the wave energy flux remaining at the shoreline. The numerical model is in agreement with the statistical data except that the undertow current is difficult to predict accurately. The measured turbulent velocities are found to be more related to the turbulent velocity estimated from the energy dissipation rate Df due to bottom friction. The suspended sediment volume expressed in terms of DB and Df can be predicted only within a factor of about 2. The roller effect represented by the roller volume flux does not necessarily improve the agreement for the three tests.
Characterization of Mg/Ca distributions in planktonic foraminifera species by electron microprobe mapping
Authors: Sadekov Aleksey Yu. , Eggins Stephen M. , De Deckker Patrick
Published: December 2005

The distribution of Mg/Ca within the tests of eight modern planktonic foraminifer species has been characterized using electron microprobe mapping. Species include several that are commonly used for estimation of past seawater temperatures (Globigerinoides ruber, G. sacculifer, Neogloboquadrina incompta (synonym of N. pachyderma dex.), N. dutertrei, and G. truncatulinoides). Each of the investigated species displays large variations in Mg/Ca composition within individual tests. However, the pattern of Mg/Ca variation is notably different between symbiont‐bearing and symbiont‐free species. In symbiotic species, cyclic Mg/Ca compositional banding occurs that is characterized by narrow (<1–3 μm), high‐Mg/Ca (typically 8–11 mmol/mol) bands, intercalated between broader low Mg/Ca (typically 1–5 mmol/mol) bands. This factor of 2–3 difference equates to an apparent calcification temperature change of 10°C or more. Such temperature changes are considered highly improbable and suggest vital effects significantly modify the incorporation of Mg/Ca into the tests of symbiont‐bearing species. These vital effects remain poorly understood and demand further careful evaluation as they may need to be accounted for when making reliable reconstructions of past oceanic temperatures. Symbiont‐free species typically have fewer and broader compositional bands that may reflect more closely changes in calcification temperature as these species migrate within a water column.
Relationship between bend‐faulting at trenches and intermediate‐depth seismicity
Authors: Ranero César R. , Villaseñor Antonio , Phipps Morgan Jason , Weinrebe Wilhelm
Published: December 2005

We have studied faulting associated with bending of the incoming oceanic plate along segments of Middle America and Chile subduction zones and its relationship to intermediate‐depth intraslab seismicity and slab geometry. Multibeam bathymetry shows that bending‐related faulting forms patterns made of sets of faults with orientations ranging from parallel to almost perpendicular to the trench axis. These fault patterns may change along a single subduction zone within along‐strike distances of several hundred kilometers or less. Where available, near‐trench intraplate earthquakes show normal‐fault focal mechanisms consistent with mapped bending‐related normal faults. The strike of bending‐related faults in the incoming oceanic plate is remarkably similar to the strike of the nodal planes of intermediate‐depth earthquakes for each segment of the study areas. This similarity in strike is observed even for faults oriented very oblique to the trench and slab strikes. Thus, in the studied subduction zones, results strongly support that many intraslab earthquakes do not occur along the planes of maximum shear within the slab and that much intermediate‐depth seismicity occurs by reactivation of faults formed by plate bending near the trench. Furthermore, a qualitative relationship between trench faulting and intraslab seismicity is indicated by segments of the incoming plate with pervasive bend‐faulting that correspond to segments of the slabs with higher intermediate‐depth seismicity.
HF‐induced airglow at magnetic zenith: Thermal and parametric instabilities near electron gyroharmonics
Authors: Mishin E. V. , Kosch M. J. , Pedersen T. R. , Burke W. J.
Published: December 2005

We analyze airglow induced by intense radio waves at the High‐frequency Active Auroral Research Program (HAARP) facility for pump frequencies f0 near the second and third electron gyroharmonic (fc). While passing through the double resonance in the weakening ionosphere during heating at f0 ∼ 2fc, airglow intensities rose abruptly and remained elevated during four consecutive pulses. During this period both the thermal and parametric instabilities coexisted. Subsequently, the thermal parametric instability was hampered. The effectiveness of heating near the second gyroharmonic is ascribed to specific dispersion characteristics near the double resonance. The observations suggest that Langmuir waves participate in cyclotron acceleration when the local plasma and second gyroharmonic frequencies match. With f0 ∼ 3fc the airglow terminated due to the suppression of cyclotron acceleration and parametric decay instability.
Bimodality of the North Atlantic Oscillation in simulations with greenhouse gas forcing
Authors: Coppola E. , Kucharski F. , Giorgi F. , Molteni F.
Published: December 2005

Using high‐resolution global “time‐slice” climate change simulations, we show the existence of a bimodal NAO distribution in future climate conditions under the IPCC A2 scenario forcing. The current climate exhibits a unimodal NAO distribution. The second “regime” in the future climate experiment is located in the positive region of the NAO phase space at about one standard deviation from the maximum, which is located near zero or at slightly negative NAO values. This additional regime grows at the expense of negative NAO occurrences. The change in the NAO distribution is physically related to negative PNA‐like change occurring in the Pacific region. The interpretation of the occurrence of the second NAO maximum in the future climate simulation is that large positive NAO events will occur more frequently in future climate conditions, while the rest of the NAO frequency distribution shows only small changes. This implies that European winter climate is expected to show higher variability and increased occurrence of extreme climate conditions associated with the positive NAO phase.
The 2004 Mw6.0 Parkfield, California, earthquake: Inversion of near‐source ground motion using multiple data sets
Authors: Custódio Susana , Liu Pengcheng , Archuleta Ralph J.
Published: December 2005

On 28 September 2004, the Mw6.0 Parkfield earthquake became the most densely recorded earthquake for near‐source ground‐motion. To infer the kinematic nature of this event we invert the strong‐motion data. The non‐linear global inversion yields slip amplitude, slip rake, average rupture velocity, and rise time over the fault. By using subsets of the data, we study the dependence of the kinematic solutions on data input. The inversions reveal that the slip amplitude was less than 0.65 m and outline two major areas of slip; one that laterally surrounds the hypocenter, preferentially extending to its SE; the other 10 to 20 km NW of the hypocenter, at a depth between 2 and 8 km. The slip amplitude we obtain for each point on the fault varies less than 0.15 m depending on data set used; the rake angle variability is less than 40°.
Solid and grid sphere current collection in view of the tethered satellite system TSS 1 and TSS 1R mission results
Authors: Khazanov G. V. , Krivorutsky E. , Sheldon R. B.
Published: December 2005

Passive end body plasma contactors have been operationally validated in space and have been shown to provide a simple, effective, and robust means of current collection at the positive terminal of an electrodynamic tether system. A grid sphere has been suggested as a possible end body since it potentially has distinct advantages compared to a solid sphere, including a lower neutral dynamic drag and a higher current‐to‐mass ratio. This paper estimates the maximum current collected by a grid sphere, taking into account its orbital motion and ion production inside the grid sphere. We first review the data from the tethered satellite system (TSS 1) and the TSS 1R flights, formulate a model for current collection by a solid sphere, and suggest how to incorporate it into the grid sphere current collection estimate. Then we calculate the potential distribution inside the grid sphere and the potential distribution outside the solid sphere for the same system parameters. Finally, we estimate the maximum current collected by a grid sphere depending on its transparency.
Dynamical consequences of two modes of centrifugal instability in Jupiter's outer magnetosphere
Authors: Kivelson M. G. , Southwood D. J.
Published: December 2005

Important global‐scale properties of the middle and outer portions of the Jovian magnetosphere can be interpreted in terms of plasma experiencing either marginal or explosive centrifugal instability as a response to rotational stresses. The process accounts for characteristics of the plasmasheet, particularly a strong dawn‐dusk asymmetry, inferred from magnetic field data. Confining forces externally imposed at the magnetopause are critical to this analysis. Because of the vast length of magnetospheric flux tubes, most plasma‐disk ions do not bounce between mirror points as a flux tube rotates through local time sectors. Rotational stresses can lead to irreversible heating and increase plasma anisotropy, creating the conditions for firehose instability. The outer edge of the plasma disk appears marginally stable prenoon, but there is weak loss of plasma from its outer edge. The plasma disk thickens further postnoon as it assimilates the empty flux tubes of the outer magnetosphere where small perpendicular scale instability enables Bohm diffusion of plasma to refill depleted flux tubes. On the nightside, the plasmasheet becomes strongly unstable, material flows out down tail, the plasma disk thins, and its outer portions can break off leaving depleted closed flux tubes behind. This outflow must dominate solar wind‐controlled reconnection in the magnetotail. The depleted flux tubes at large radial distance on the morningside form a distinct low‐density plasma/magnetic regime that overlays a thin plasma disk. The dawn‐dusk asymmetry in the UV aurora is likely associated with the larger tapping of the ionospheric flywheel in the afternoon sector to drive the heating and instability that the model proposes.
The IDV index: Its derivation and use in inferring long‐term variations of the interplanetary magnetic field strength
Authors: Svalgaard Leif , Cliver Edward W.
Published: December 2005

On the basis of a consideration of Bartels' historical u index of geomagnetic activity, we devise an equivalent index that we refer to as the interdiurnal variability (IDV). The IDV index has the interesting and useful property of being highly correlated with the strength of the interplanetary magnetic field (B; R2 = 0.75) and essentially unaffected by the solar wind speed (V; R2 = 0.01) as measured by spacecraft. This enables us to obtain the variation of B from 1872 to the present, providing an independent check on previously reported results for the evolution of this parameter. We find that solar cycle average B increased by ∼25% from the 1900s to the 1950s and has been lower since. If predictions for a small solar cycle 24 bear out, solar cycle average B will return to levels of ∼100 years ago during the coming cycle(s).
Spatial patterns and mechanisms of the quasi‐biennial oscillation–annual beat of ozone
Authors: Jiang Xun , Jones Dylan B. A. , Shia Runlie , Waliser Duane E. , Yung Yuk L.
Published: December 2005

An idealized two‐dimensional chemistry and transport model is used to investigate the spatial patterns of, and mechanism for, the quasi‐biennial oscillation–annual beat (QBO‐AB) signal in ozone in the tropics and subtropics. Principal component analysis is applied to the detrended, deseasonalized, and filtered total column ozone anomaly from the standard model. The first two empirical orthogonal functions (EOFs) capture over 98.5% of the total variance. The first EOF, accounting for 70.3% of the variance, displays a structure attributable to the approximately symmetric QBO with a period of 28 months. The second EOF, capturing 28.2% of the variance, is related to the QBO‐AB around 20 months. An extended EOF analysis reveals the characteristic pattern of the downward propagation of QBO and upward propagation of QBO‐AB. The model results are compared to those from the merged ozone data. Sensitivity experiments indicate that the QBO‐AB is produced primarily as a result of the dynamical QBO‐AB in the mean meridional circulation and by the interaction between the QBO and the annual cycle in transport, each contributing roughly equally to the forcing of QBO‐AB. The interaction between the QBO in the transport fields and the annual cycle in chemistry plays a minor role.