bluuebunny/crossref_metadata_2025 huggingface dataset:
A simulation study of odds ratio estimation for binary outcomes from cluster randomized trials
Authors: Ukoumunne Obioha C. , Carlin John B. , Gulliford Martin C.
Published: December 2006

We used simulation to compare accuracy of estimation and confidence interval coverage of several methods for analysing binary outcomes from cluster randomized trials. The following methods were used to estimate the population‐averaged intervention effect on the log‐odds scale: marginal logistic regression models using generalized estimating equations with information sandwich estimates of standard error (GEE); unweighted cluster‐level mean difference (CL/U); weighted cluster‐level mean difference (CL/W) and cluster‐level random effects linear regression (CL/RE). Methods were compared across trials simulated with different numbers of clusters per trial arm, numbers of subjects per cluster, intraclass correlation coefficients (ρ), and intervention versus control arm proportions. Two thousand data sets were generated for each combination of design parameter values. The results showed that the GEE method has generally acceptable properties, including close to nominal levels of confidence interval coverage, when a simple adjustment is made for data with relatively few clusters. CL/U and CL/W have good properties for trials where the number of subjects per cluster is sufficiently large and ρ is sufficiently small. CL/RE also has good properties in this situation provided a t‐distribution multiplier is used for confidence interval calculation in studies with small numbers of clusters. For studies where the number of subjects per cluster is small and ρ is large all cluster‐level methods may perform poorly for studies with between 10 and 50 clusters per trial arm. Copyright © 2006 John Wiley & Sons, Ltd.
The impact of technology on the enactment of “inquiry” in a technology enthusiast's sixth grade science classroom
Authors: Waight Noemi , Abd‐El‐Khalick Fouad
Published: December 2006

This study investigated the impact of the use of computer technology on the enactment of “inquiry” in a sixth grade science classroom. Participants were 42 students (38% female) enrolled in two sections of the classroom and taught by a technology‐enthusiast instructor. Data were collected over the course of 4 months during which several “inquiry” activities were completed, some of which were supported with the use of technology. Non‐participant observation, classroom videotaping, and semi‐structured and critical‐incident interviews were used to collect data. The results indicated that the technology in use worked to restrict rather than promote “inquiry” in the participant classroom. In the presence of computers, group activities became more structured with a focus on sharing tasks and accounting for individual responsibility, and less time was dedicated to group discourse with a marked decrease in critical, meaning‐making discourse. The views and beliefs of teachers and students in relation to their specific contexts moderate the potential of technology in supporting inquiry teaching and learning and should be factored both in teacher training and attempts to integrate technology in science teaching. © 2006 Wiley Periodicals, Inc. J Res Sci Teach
Exploring teachers' informal formative assessment practices and students' understanding in the context of scientific inquiry
Authors: Ruiz‐Primo Maria Araceli , Furtak Erin Marie
Published: December 2006

This study explores teachers' informal formative assessment practices in three middle school science classrooms. We present a model for examining these practices based on three components of formative assessment (eliciting,recognizing, andusing information) and the three domains linked to scientific inquiry (epistemic frameworks, conceptual structures, and social processes). We describe the informal assessment practices as ESRU cycles—the teacherElicits a question; theStudent responds; the teacherRecognizes the student's response; and thenUses the information collected to support student learning. By tracking the strategies teachers used in terms of ESRU cycles, we were able to capture differences in assessment practices across the three teachers during the implementation of four investigations of a physical science unit on buoyancy. Furthermore, based on information collected in a three‐question embedded assessment administered to assess students' learning, we linked students' level of performance to the teachers' informal assessment practices. We found that the teacher who more frequently used complete ESRU cycles had students with higher performance on the embedded assessment as compared with the other two teachers. We conclude that the ESRU model is a useful way of capturing differences in teachers' informal assessment practices. Furthermore, the study suggests that effective informal formative assessment practices may be associated with student learning in scientific inquiry classrooms. © 2006 Wiley Periodicals, Inc. J Res Sci Teach
The effects of a history‐based instructional material on the students' understanding of field lines
Authors: Pocoví M. Cecilia
Published: December 2006

Many students in physics courses fail to achieve a desired conceptual change because they assign an incorrect ontology to the to‐be‐learned concept. This situation has been detected in previous research for the case of field lines: many college students assign material properties to the lines and describe them, for example, as tubes that contain or transport charges. The historical evolution of this concept shows that early scientists like Faraday assigned material properties to these lines in some occasions. In the present work a history‐based instructional material was designed to foster the analysis of the ontology of field lines to help students at an Argentinean university achieve conceptual change. The predicates used by the students to describe physical situations were used as evidence of the assigned ontological status. Conceptual change was measured by the change in the proportion of geometrical predicates that students used when referring to the lines in a written questionnaire. This change was significantly higher for the students learning with the history‐based material compared to those that learned in the regular class. Some characteristics of the material and geometrical ideas that students hold about the field lines were determined through an oral interview. © 2006 Wiley Periodicals, Inc. J Res Sci Teach
Criterion for surface contact deformation of metals
Authors: Jamari J. , Schipper D.J.
Published: December 2006

In most engineering applications, bulk plastic deformation of the surface is avoided. There is, however, no criterion for determining whether or not bulk plastic deformation occurs during the contact between rough surfaces. This paper presents a criterion for predicting the deformation behaviour of the contact between a real rough surface against a curved body. In order to verify the proposed criterion, experimental investigations were carried out for three different materials. It was found that the experimental results confirmed the proposed criterion very well. For a given operational contact condition, a contact system where bulk deformation does not occur can be designed using this criterion. If the criterion value Cm is less than 0.52 plastic deformation occurs on asperity level only and there is no bulk deformation, but if Cm is greater than 0.52 there are two possible deformation modes, i.e. plastic deformation of the bulk and plastic deformation in both the asperity and the bulk. Copyright © 2006 John Wiley & Sons, Ltd.
Experimental evaluation of friction between contacting discs for the simulation of gear contact
Authors: Kleemola J. , Lehtovaara A.
Published: December 2006

Instant gear contact can be simulated with contacting discs, which provides steady operating conditions and eliminates most of the dynamics and manufacturing tolerances involved in real gears, resulting in an accurately controlled contact condition. A high‐pressure twin‐disc test device was developed, where loading and rolling velocity can be varied continuously. It is equipped with disc bulk temperature, mean contact resistance and friction moment measurements. The test discs were grinded transversal to the disc rolling direction with proper crowning corresponding to the real gear flank properties. The test device was applied by studying the friction behaviour against the slide‐to‐roll ratio at different contact pressures, rolling velocities and surface roughness. The measurements were performed using mineral base oil in the range of operation conditions often used in industrial gears. In general, the measured friction coefficient behaviour correlates with earlier published results and is logical with measured bulk temperature and mean contact resistance. The limiting shear stress of the lubricant has an essential role in friction behaviour. Copyright © 2006 John Wiley & Sons, Ltd.
Reliability of a machine service life prediction in thermal diagnostic test
Authors: Burstein L.
Published: December 2006

Reliability of the machine service life determined in a thermal diagnostic test is estimated in this investigation. The time dependence of a thermal diagnostic parameter, and the residual service life (RSL) predicted on its basis, are examined here with the aid of the Monte‐Carlo simulation procedure. The relationships involved are derived from the machine heat balance under two approaches – short term (starting stage) and long term (service time). The diagnostic parameter considered is the temperature change rate during the short‐term period. The constants in its expression are determined from experimental data obtained as an example on the gearboxes of three heavy portal cranes with different service times. The diagnostic parameter–time graph (long‐term approach) derived from the data is used as reference for prediction of the RSL. The reference dependence obtained from theoretical values of the diagnostic parameter, and the RSL calculated from this dependence, were repeatedly varied, with a view to estimating the reliability of the prediction. The uniform and Weibull distributions were used for generating, respectively, the random fluctuations of the reference gearbox temperature and of the diagnostic parameter of the tested one. It is shown that in 95% of the cases the thermal method entails a two‐sided error of at most 3.6%, and for the tested gearbox the discrepancy between the deterministic and simulated averages does not exceed 1.1%. Copyright © 2006 John Wiley & Sons, Ltd.
Interaction of rice dwarf virus outer capsid P8 protein with rice glycolate oxidase mediates relocalization of P8
Authors: Zhou Feng , Wu Gang , Deng Wulan , Pu Yingying , Wei Chunhong , Li Yi
Published: December 2006

Yeast two‐hybrid and coimmunoprecipitation assays indicated that P8, an outer capsid protein of Rice dwarf phytoreovirus (RDV), interacts with rice glycolate oxidase (GOX), a typical enzyme of peroxisomes. Confocal immunofluorescence microscopy revealed that P8 was colocalized with GOX in peroxisomes. Time course analysis demonstrated that the localization of P8 in Spodoptera frugiperda cells changed from diffuse to discrete, punctuate inclusions during expression from 24 to 48 h post inoculation. Coexpression of GOX with P8 may target P8 into peroxisomes, which serve as replication sites for a number of viruses. Therefore, we conclude that the interaction of P8 with the GOX of host cells leads to translocation of P8 into peroxisomes and we further propose that the interaction between P8 and GOX may play important roles in RDV targeting into the replication site of host cells. Our findings have broad significance in studying the mechanisms whereby viruses target appropriate replication sites and begin their replication.
Unilateral facial nerve paralysis after electrocution injury
Authors: Ahmed I , Farhan W , Durham L
Published: December 2006

We present a case of acute, unilateral facial nerve paralysis in a patient who had received a low voltage electrical current. This is an extremely rare cause of this neurological condition. The patient regained complete neurological function approximately three months after the incident. Unilateral facial nerve paralysis most commonly occurs due to infection or blunt or penetrating trauma; it has not been previously reported as a result of low voltage electrical injury.
The unified theory of repression
Authors: Erdelyi Matthew Hugh
Published: December 2006

Repression has become an empirical fact that is at once obvious and problematic. Fragmented clinical and laboratory traditions and disputed terminology have resulted in a Babel of misunderstandings in which false distinctions are imposed (e.g., between repression and suppression) and necessary distinctions not drawn (e.g., between the mechanism and the use to which it is put, defense being just one). “Repression” was introduced by Herbart to designate the (nondefensive) inhibition of ideas by other ideas in their struggle for consciousness. Freud adapted repression to the defensive inhibition of “unbearable” mental contents. Substantial experimental literatures on attentional biases, thought avoidance, interference, and intentional forgetting exist, the oldest prototype being the work of Ebbinghaus, who showed that intentional avoidance of memories results in their progressive forgetting over time. It has now become clear, as clinicians had claimed, that the inaccessible materials are often available and emerge indirectly (e.g., procedurally, implicitly). It is also now established that the Ebbinghaus retention function can be partly reversed, with resulting increases of conscious memory over time (hypermnesia). Freud's clinical experience revealed early on that exclusion from consciousness was effected not just by simple repression (inhibition) but also by a variety of distorting techniques, some deployed to degrade latent contents (denial), all eventually subsumed under the rubric of defense mechanisms (“repression in the widest sense”). Freudian and Bartlettian distortions are essentially the same, even in name, except for motive (cognitive vs. emotional), and experimentally induced false memories and other “memory illusions” are laboratory analogs of self-induced distortions.
Simulation constraints, afterlife beliefs, and common-sense dualism
Authors: Antony Michael V.
Published: December 2006

Simulation constraints cannot help in explaining afterlife beliefs in general because belief in an afterlife is a precondition for running a simulation. Instead, an explanation may be found by examining more deeply our common-sense dualistic conception of the mind or soul.
Social cognition of religion
Authors: Bainbridge William Sims
Published: December 2006

Research on religion can advance understanding of social cognition by building connections to sociology, a field in which much cognitively oriented work has been done. Among the schools of sociological thought that address religious cognition are: structural functionalism, symbolic interactionism, conflict theory, phenomenology, and, most recently, exchange theory. The gulf between sociology and cognitive science is an unfortunate historical accident.
Can repression become a conscious process?
Authors: Boag Simon
Published: December 2006

A major weakness in Erdelyi's account concerns the claim that repression can become conscious. A relational account of cognition demonstrates that if repression is successful, then the repressive act cannot become known. Additionally, “resistance” further distinguishes “repression” from “suppression.” Rather than blurring the distinction between these processes, it is possible to recognise a series of defences. Suggestions are provided for alternative research avenues.
Motive and consequence in repression
Authors: Boden Joseph M.
Published: December 2006

Erdelyi's unified theory of repression offers a significant advance in understanding the disparate findings related to repression. However, the theory de-emphasizes the role of motive in repression, and it is argued here that motive is critical to the understanding of repression as it occurs in the mental life of individuals.
Prosocial aspects of afterlife beliefs: Maybe another by-product
Authors: Boyer Pascal
Published: December 2006

Bering argues that belief in posthumous intentional agency may confer added fitness via the inhibition of opportunistic behavior. This is true only if these agents are interested parties in our moral choices, a feature which does not result from Bering's imaginative constraint hypothesis and extends to supernatural agents other than dead people's souls. A by-product model might handle this better.
What Erdelyi has repressed
Authors: Crews Frederick
Published: December 2006

Erdelyi's “unified theory of repression” attempts to rehabilitate psychoanalytic doctrine by exaggerating its compatibility with the findings of cognitive science. In addition, Erdelyi treats Freud's writings as holy writ, any portion of which can be quoted to prove a point. He also relies on a long-discredited account of Freud's “seduction theory” and ignores important links between Freudian assumptions and our recent recovered memory movement.
Freud did not anticipate modern reconstructive memory processes
Authors: Esterson Allen , Ceci Stephen J.
Published: December 2006

In this commentary, we challenge the claim that Freud's thinking anticipated Bartlettian reconstructive theories of remembering. Erdelyi has ignored important divergences that demonstrate it is not the case that “The constructions and reconstructions of Freud and Bartlett are the same but for motive” (target article, sect. 5).
Culture and development matter to understanding souls, no matter what our evolutionary design
Authors: Ferrari Michel
Published: December 2006

For Bering, appreciating that people are objects is a developmental accomplishment. Baldwin and Piaget agree. However, for Piaget, an immanent conception of the divine is more developed than a separate transcendent God. Culture also matters. In Plato's Phaedo, Socrates' belief in immortality was a reasoned conclusion – not “built in” – for reasons similar to those still held by modern scientists.
Reduced autobiographical memory specificity, avoidance, and repression
Authors: Hermans Dirk , Raes Filip , Iberico Carlos , Williams J. Mark G.
Published: December 2006

Recent empirical work indicates that reduced autobiographical memory specificity can act as an avoidant processing style. By truncating the memory search before specific elements of traumatic memories are accessed, one can ward off the affective impact of negative reminiscences. This avoidant processing style can be viewed as an instance of what Erdelyi describes as the “subtractive” class of repressive processes.
Repression and the unconscious
Authors: Langnickel Robert , Markowitsch Hans
Published: December 2006

We argue that repression is primarily an unconscious process and that the position of Erdelyi is not coherent with Freud's views on the matter. Repression of ideas is a process that takes place without the knowledge of the subject. In this respect, it is essentially different from suppression, where ideas are acted upon by a conscious will.
Learning that there is life after death
Authors: Harris Paul L. , Astuti Rita
Published: December 2006

Bering's argument that human beings are endowed with a cognitive system dedicated to forming illusory representations of psychological immortality relies on the claim that children's beliefs in the afterlife are not the result of religious teaching. We suggest four reasons why this claim is unsatisfactory.
Folk psychology meets folk Darwinism
Authors: Hegdé Jay , Johnson Norman A.
Published: December 2006

The fact that beliefs in the supernatural are useful to people who hold them does not necessarily mean that these beliefs confer an evolutionary advantage to those who hold them. An evolutionary explanation for any biological phenomenon must meet rigorous criteria, but the facts in this case, even when taken at their face value, fall well short of these criteria.
Natural selection and religiosity: Validity issues in the empirical examination of afterlife cognitions
Authors: Hughes Brian M.
Published: December 2006

Bering's target article proposes that the tendency to believe in an afterlife emerged (in evolutionary history) in response to selective pressures unique to human societies. However, the empirical evidence presented fails to account for the broader social context that impinges upon researcher–participant interactions, and so fails to displace the more parsimonious explanation that it is childhood credulity that underlies the acquisition of afterlife beliefs through cultural exposure.
Learning from repression: Emotional memory and emotional numbing
Authors: Medford Nick , David Anthony S.
Published: December 2006

Erdelyi argues persuasively for his unified theory of repression. Beyond this, what can studying repression bring to our understanding of other aspects of emotional function? Here we consider ways in which work on repression might inform the study of, on one hand, emotional memory, and on the other, the emotional numbing seen in patients with chronic persistent depersonalization symptoms.
The United States of Repression
Authors: Najmi Sadia , Wegner Daniel M.
Published: December 2006

Erdelyi's account of thought suppression, which he equates with the Freudian construct of repression, is that it is mostly successful, and that it undermines memory for the suppressed material. Erdelyi has neglected to consider evidence from two decades of research on suppression which renders both these claims invalid. Contrary to Erdelyi's thesis, suppression often enhances the accessibility of unwanted material.
Cultural adaptation and evolved, general-purpose cognitive mechanisms are sufficient to explain belief in souls
Authors: Livingston Kenneth R.
Published: December 2006

It is suggested that general-purpose cognitive modules are the proper endophenotypes on which evolution has operated, not special purpose belief modules. These general-purpose modules operate to extract adaptive cultural patterns. Belief in souls may be adaptive and based in evolved systems without requiring that a specific cognitive system has evolved to support just such beliefs.
Beliefs in afterlife as a by-product of persistence judgments
Authors: Newman George E. , Blok Sergey V. , Rips Lance J.
Published: December 2006

We agree that supernatural beliefs are pervasive. However, we propose a more general account rooted in how people trace ordinary objects over time. Tracking identity involves attending to the causal history of an object, a process that may implicate hidden mechanisms. We discuss experiments in which participants exhibit the same “supernatural” beliefs when reasoning about the fates of cups and automobiles as those exhibited by Bering's participants when reasoning about spirits.
The Godfather of soul
Authors: Preston Jesse , Gray Kurt , Wegner Daniel M.
Published: December 2006

An important component of souls is the capacity for free will, as the origin of agency within an individual. Belief in souls arises in part from the experience of conscious will, a compelling feeling of personal causation that accompanies almost every action we take, and suggests that an immaterial self is in charge of the physical body.
The mnemic neglect model: Experimental demonstrations of inhibitory repression in normal adults
Authors: Sedikides Constantine , Green Jeffrey D.
Published: December 2006

Normal adults recall poorly social feedback that refers to them, is negative, and pertains to core self-aspects. This phenomenon, dubbed the mnemic neglect effect, is equivalent to inhibitory repression. It is instigated under conditions of high self-threat, it implicates not-thinking during encoding, and it involves memories that are recoverable with such techniques as recognition accuracy.
The return of the repressed
Authors: Erdelyi Matthew Hugh
Published: December 2006

Repression continues to be controversial. One insight crystallized by the commentaries is that there is a serious semantic problem, partly resulting from a long silence in psychology on repression. In this response, narrow views (e.g., that repression needs always be unconscious, must yield total amnesia) are challenged. Broader conceptions of repression, both biological and social, are considered, with a special stress on repression of meanings (denial). Several issues – generilizability, falsifiability, personality factors, the interaction of repression with cognitive channel (e.g., recall vs. dreams), and false-memory as repression – are discussed.
Total electron content (TEC) variability at Los Alamos, New Mexico: A comparative study: 2. Comparisons with other TEC sources
Authors: Huang Zhen , Roussel‐Dupré Robert
Published: December 2006

In this study, the Fast On‐Orbit Recording of Transient Events (FORTE) derived TEC variabilities on a diurnal cycle, seasonal cycle, 11‐year solar cycle, and 27‐day solar cycle are compared with the TEC estimates from the Los Alamos ionospheric transfer function implemented with the International Reference Ionosphere model, the GPS‐derived TEC maps from NOAA, the GPS measurements made at Los Alamos, and the ionosonde critical frequency data at the closest station, Boulder, Colorado. The results show good agreement on average (monthly, annual, or multiyear means) in TEC variability at Los Alamos between the various data sources with relative RMS errors of about 5–10%. The results also show RMS errors larger than 30% for point‐to‐point comparisons, with the most significant errors found during high solar activity years, during summer seasons, and during strong geomagnetic storm conditions. This comparative study suggests that the FORTE‐derived TECs combined with other TEC sources can help to better understand the TEC variability at Los Alamos in providing more accurate time‐dependent site TECs than those derived from a single source or extrapolated from global model predictions.
Tectonic stress and magma chamber size as controls on dike propagation: Constraints from the 1975–1984 Krafla rifting episode
Authors: Buck W. Roger , Einarsson Páll , Brandsdóttir Bryndís
Published: December 2006

The best‐studied dike intrusion events on a divergent plate boundary occurred along the Krafla segment of the northern rift zone in Iceland from 1975–1984. Seismic and geodetic measurements there showed that a central magma chamber fed dikes that propagated laterally many times the thickness of the lithosphere. The patterns of dike length, dike width, caldera subsidence, and lava extrusion strongly suggest that dike propagation is affected by tectonic stresses that change with each dike intrusion event and that magma pressures are linked to the dike opening. These observations have inspired us to develop a quantitative model for the lateral propagation of basaltic dikes away from a magma chamber. We assume dikes propagate as long as there is sufficient driving pressure, defined as the difference between magma pressure and tectonic stress at the dike tip. The opening dike and the magma chamber are treated as a closed system for a given dike intrusion event. During an event, magma pressure is reduced linearly with the magma volume withdrawn from the chamber. Relative tectonic tension in the lithosphere is reduced linearly as the dike width increases. A dike begins propagation when the driving pressure equals the “breakout” pressure needed to force the magma out of the chamber. It stops when the driving pressure reaches a minimum value. Generally, the dike width is proportional to this “stopping” pressure, and a reasonable value gives a width of 1 m. Besides the breakout and stopping pressures, the propagation distance depends on the initial distribution of tectonic stress and the thickness of the lithosphere cut by a dike. The intrusion of a dike changes the tectonic stress distribution so that subsequent dikes may propagate different distances and directions than the first dike. After a period of magma chamber refilling, a new dike can initiate if the breakout pressure is reached. For an idealized spreading segment the tectonic stress field evolves to produce a sequence of dikes propagating in one direction followed by a sequence of dikes propagating in the opposite direction. The first dike in each sequence should be the longest followed by successively shorter dikes. When tectonic stresses close to a magma chamber have been largely relieved, then extrusion of magma may start. The model pattern of dike propagation and extrusion is consistent with data from the Krafla episode. Magma chamber size should have a major effect on magmatic systems in other tectonic settings with larger magma chambers producing longer characteristic dikes.
On the bottom density plume on coastal zone off Gargano (Italy) in the southern Adriatic Sea and its interannual variability
Authors: Wang X. H. , Oddo P. , Pinardi N.
Published: December 2006

The Adriatic Sea general circulation model (AIM) was implemented to study a bottom density plume found in coastal zone off Gargano (hereafter Gargano bottom density plume) in the southern Adriatic Sea (SAS), Italy, and its interannual variability. The model has been run with realistic wind stress, surface heat flux, and river runoff forcings continuously for a period from 1 January 1999 to 31 December 2002. The study found that the Gargano bottom density plume, typically as found in spring 2000, is a bottom density current driven by a perturbation in density as a result of successive bora cooling events in the northern Adriatic Sea (NAS) from previous autumn and winter. The density current advects cold and less saline Northern Adriatic Deep Water (NADDW) from the NAS to the SAS, and the propagation speed of the plume can reach 0.1 m s−1 with a downslope component on the order of 0.05 m s−1. The southward mass and heat transport by the Gargano plume can be calculated to be 0.08 Sv and −30 W m−2 at a transect near Gargano Peninsula. These results suggest that about 15% of the NADDW and NAS heat content change produced over previous winter was transported to the SAS by the Gargano plume. One of the most important findings of this paper is that there is a connection between the intensity of Gargano bottom density plume in the SAS and the NADDW production rates in the NAS. The numerical study demonstrated that a continuous heat loss of 175 W m−2 from November to January is required to produce adequate volume of NADDW, so that a density perturbation is formed which is large enough to drive a density current that reaches the Gargano Peninsula in the spring. This minimum requirement of heat loss equates to eight consecutive strong bora events in this period. In addition to the autumn and winter surface cooling, summer preconditioning of the NAS density by the lower Po River runoff is another important factor in the Gargano plume generation. A wet summer results in large Po River runoff and decreases the NAS density. Thus additional heat loss is required for adequate NADDW production in the following winter. Finally, the study also demonstrated that total heat budget of the NAS during the winter season was negative, as the amount of heat lost at the air‐sea interface during that period was much larger than the amount of heat gained by horizontal advection. As a result, the NAS during the winter season experienced a strong heat content decrease.
February 2003 marine atmospheric conditions and the bora over the northern Adriatic
Authors: Dorman C. E. , Carniel S. , Cavaleri L. , Sclavo M. , Chiggiato J. , Doyle J. , Haack T. , Pullen J. , Grbec B. , Vilibić I. , Janeković I. , Lee C. , Malačič V. , Orlić M. , Paschini E. , Russo A. , Signell R. P.
Published: December 2006

A winter oceanographic field experiment provided an opportunity to examine the atmospheric marine conditions over the northern Adriatic. Mean February winds are from a northeasterly direction over most of the Adriatic and a more northerly direction along the western coast. Wind speeds are fastest in jets over the NE coast during bora events and weakest in the mid‐northwestern Adriatic. Diurnal air temperature cycles are smallest on the NE coast and largest in the midwestern Adriatic. The maximum sea‐air difference is +10°C on the eastern coast and near zero on the midwestern Adriatic. Boras are northeasterly (from) wind events that sweep off Croatia and Slovenia, bringing slightly colder and drier air over the northern Adriatic. The main bora season is December to March. Winter 2002–2003 was normal for bora events. Synoptic‐scale temporal variations are correlated over the northern Adriatic. Fastest Bora winds and highest wind stress over the northern Adriatic is concentrated in four topographically controlled jets. The strongest is the Senj Jet, while the Trieste Jet extends across the entire northern Adriatic. Between each two jets is a weak wind zone. The greatest mean net heat loss is in bora jets in the NE Adriatic, where it was −438 W m−2 and is weakest in the midwestern northern Adriatic, where it was near zero. Wind stress is concentrated over the NE half of Adriatic in four bora jets, while wind stress is weak in the NW Adriatic. There is significant variation in wind stress mean and standard deviation structure over the northern Adriatic with each bora event.
Physical control on the seasonal cycle of surface pCO2 in the equatorial Pacific
Authors: Jiang Mingshun , Chai Fei
Published: December 2006

The controlling mechanism of the seasonal cycle of surface partial pressure of CO2 (pCO2) in the central/eastern equatorial Pacific is studied using a coupled physical‐biogeochemical model. The model results indicate that the individual components of physical transport of total CO2 (TCO2) in the Niño3 area are out of phase with each other such that the net TCO2 transport is an order smaller. This net transport is further nearly balanced by the biological drawdown and air‐sea CO2 flux combined, resulting in a weak seasonality of surface TCO2. As a consequence, the seasonal cycle of sea surface temperature (SST) controls the surface pCO2 cycle with a maximum in boreal spring‐summer and a minimum in boreal fall‐winter. In turn, the seasonality of air‐sea CO2 flux is largely controlled by SST and surface winds via the piston velocity of gas exchange. Perturbations to the subtle balance of TCO2 transport by dynamical processes on other timescales such as El Niño, La Niña and tropical instability waves, could induce significant change to the surface pCO2, in addition to the change due to SST variability.
Timing of global warming in IPCC AR4 AOGCM simulations
Authors: Kattsov Vladimir M. , Sporyshev Petr V.
Published: December 2006

Spatio‐temporal features are considered of statistically significant stable change of surface air temperature obtained from 20th and 21st century simulations using a 17‐member ensemble of global climate models forced with evolving green house gas and sulfate aerosol atmospheric concentrations. The analysis shows that the tropical Indian Ocean and western Pacific, on the one hand, and the northern North Atlantic and Southern Ocean, on the other hand, stand out as the most contrasting features of the ensemble mean timing distribution. The former are characterized by the earliest warming, while the latter demonstrate latest or not achieved stable changes of the temperature. Qualitative agreement between the model‐ and observationally derived global pictures of the stable change timing offers an opportunity to test model performance in reproducing the forced climate evolution. An illustration is given of the model performance evaluation based on the test application.
Carbon isotope ratios of organic compound fractions in oceanic suspended particles
Authors: Hwang Jeomshik , Druffel Ellen R. M.
Published: December 2006

To study cycling of organic fractions in the ocean, relative abundances and radio‐ and stable‐carbon isotope measurements of total lipid extract, acid‐soluble, and acid‐insoluble fractions of suspended particulate organic carbon (POC) were made. Changes in relative abundances occurred mostly in the upper 1000 m of the water column, with a decrease in total lipid extract and the acid‐soluble fraction and an increase in the acid‐insoluble fraction with increasing depth. We found lower Δ14C values for total lipid extract and the acid‐insoluble fraction than for the acid‐soluble fraction, which is consistent with the previous suggestion of incorporation of dissolved organic carbon and/or resuspended sediment to POC (Druffel and Williams, 1990; Sherrell et al., 1998). The Δ14C values of these fractions in a given organic carbon pool must be understood in terms of acquisition of 14C‐depleted carbon from other carbon pools in addition to aging within the reservoir.
Effect of climate and CO2 changes on the greening of the Northern Hemisphere over the past two decades
Authors: Piao Shilong , Friedlingstein Pierre , Ciais Philippe , Zhou Liming , Chen Anping
Published: December 2006

Study of the effect of current climate changes on vegetation growth, and their spatial patterns improves our understanding of the interactions between terrestrial ecosystems and climatic systems. This paper explores the spatial patterns of vegetation growth responding to climate variability over Northern Hemisphere (>25°N) from 1980 to 2000 using a mechanistic terrestrial carbon model. The results indicate that changes in climate and atmospheric CO2 likely function as dominant controllers for the greening trend during the study period. At the continental scale, atmospheric CO2, temperature, and precipitation account for 49%, 31%, and 13% of the increase in growing season LAI, respectively, but their relative role is not constant across the study area. The increase in vegetation activity in most of Siberia is associated with warming, while that in central North America is primarily explained by the precipitation change. The model simulation also suggests that the regression slope of LAI to temperature increases with soil moisture, but decreases with temperature. This implies that the contribution of rising temperature to the current enhanced greening trend will weaken or even disappear under continued global warming. We also find that the effects of both vegetation precipitation use efficiency and atmospheric CO2 fertilization on the greening trend increase as soil moisture becomes limiting.
Three‐dimensional micromagnetic modeling of randomly oriented magnetite grains (0.03–0.3 μm)
Authors: Fukuma Koji , Dunlop David J.
Published: December 2006

We report three‐dimensional micromagnetic structures obtained for magnetite cubes with 〈100〉 edges in the size range 0.03–0.3 μm around the single‐domain threshold size. We employed the Metropolis algorithm to find equilibrium micromagnetic structures starting from uniformly magnetized initial states. Directions of initial magnetizations were randomly set so as to mimic a randomly oriented assemblage. Small grains (<0.07 μm) exhibit single‐domain equilibrium structures parallel to a magnetic easy axis 〈111〉 irrespective of initial magnetization directions. Vortex structures emerge for small pseudosingle‐domain grains above 0.07 μm. Axes of the vortices are parallel to 〈100〉 in the threshold size range but become randomly oriented with increasing grain size. Neither lamellar domain structures nor multiple vortex structures were found for grains smaller than 0.3 μm. Reduced saturation remanent magnetization decreased down to ∼0.1 with increasing grain size over a relatively narrow grain size range (0.07–0.15 μm). The grain size variation of reduced magnetization depends on microscopic magnetization structures inside a single grain and the degree of randomness of grain magnetization directions in an assemblage.
Quantifying transdomain transitions in three dimensions and the limits of classical and metastable single‐domain behavior using field‐impressed magnetic anisotropy
Authors: Potter David K.
Published: December 2006

Some domain imaging studies have been used as evidence for transdomain transitions and metastable single‐domain states in particles larger than theoretical single‐domain (SD) size. Domain imaging has certain limitations since observations are made of a two‐dimensional surface, which is generally polished and may introduce stress effects, and usually a relatively small number of particles are analyzed. The present paper shows how field‐impressed anisotropy of magnetic susceptibility provides independent quantitative support in three dimensions for transdomain transitions and metastable SD states. In particular, changes from positive to negative impressed anisotropy (prolate to oblate impressed ellipsoids) in a direct field (DF) of increasing strength are consistent with some small multidomain (MD) particles undergoing transitions to metastable SD states. The results suggest that DF treatment can quantify the particle size limits of metastable SD behavior. In contrast, an alternating field (AF) should not produce a metastable SD state in particles greater than theoretical SD size and experimentally produces positive impressed anisotropy in MD particles and negative values only in intrinsic SD particles. Consequently, AF treatment can be used to determine the particle size limits of theoretical classical (not metastable) SD behavior. Consistent results were obtained for particle size fractions of magnetite, titanomagnetite, pyrrhotite, and hematite. The results may also help to explain recent observations concerning the low‐field variation of AC susceptibility of various minerals. Field‐impressed anisotropy is a quantitative, rapid, three‐dimensional technique, requiring no extra sample preparation (thus not introducing stress effects), and representative of a statistically large number of particles.
Introduction to the special section on Fundamental and Frontier Research in Rock Magnetism
Authors: Jackson Michael J. , Williams Wyn , Smirnov Alexei
Published: December 2006

Many of the papers in this special section were first presented in the session “Rock Magnetism: Fundamentals and Frontiers” at the 2005 Fall AGU meeting. Collectively, they represent the leading edge of research in mineral magnetism and its applications to Earth and planetary sciences, as well as a tribute to Professor D. J. Dunlop, who has made profound contributions to the field.
Tides on Europa, and the thickness of Europa's icy shell
Authors: Wahr J. M. , Zuber M. T. , Smith D. E. , Lunine J. I.
Published: December 2006

It has been shown previously that measurements of tides on Jupiter's moon Europa can be used to determine whether there is a liquid ocean beneath this moon's icy outer shell. In this paper we examine the further possibility of constraining the thickness of the icy shell in the case where a liquid ocean exists, by combining measurements of tidal gravity obtained from tracking an orbiting spacecraft with measurements of vertical tidal surface displacements obtained from a precise onboard altimeter. By simulating a 1‐month Europa mapping mission we demonstrate that this combination of tidal measurements would provide a much better estimate of ice thickness than could be obtained using either tracking or altimeter measurements alone. The thickness value inferred from the combined data would also require an estimate of the shear modulus of Europa's icy shell. This introduces an additional uncertainty in the thickness estimate that is approximately proportional to the uncertainty in the inverse of the shear modulus.
Multispecies stable isotopes of benthic foraminifers reveal past changes of organic matter decomposition and deepwater oxygenation in the Arabian Sea
Authors: Schmiedl Gerhard , Mackensen Andreas
Published: December 2006

The stable isotope composition of one epifaunal and three infaunal benthic foraminiferal species of a sediment core from 1800 m water depth of the western Arabian Sea was determined to evaluate deepwater oxygenation, organic matter remineralization, and early diagenetic processes during the past 190,000 years. The δ18O records reveal species‐specific metabolic effects, susceptibility to changes in carbonate ion concentration, and supralysoclinal calcite dissolution. The foraminiferal δ13C records reveal changes in the stable carbon isotope gradients of pore water dissolved inorganic carbon (δ13CDIC) and in the microhabitat depth of infaunal species. Maximum δ13CDIC offsets between bottom and pore waters ranged between mean values of 0.8 and 1.2‰ corresponding to estimates of deepwater oxygen concentration between approximately 1 and 2.7 mL L−1. Intervals of improved deepwater oxygenation coincided with high benthic foraminiferal diversity and indicate the admixture of well‐oxygenated deepwater masses during interglacials. During interglacial maxima the δ13C difference between epifauna and shallow infauna indicates highest organic matter remineralization rates at times of maximum organic matter fluxes.
Novel c‐MYC target genes mediate differential effects on cell proliferation and migration
Authors: Cappellen David , Schlange Thomas , Bauer Matthieu , Maurer Francisca , Hynes Nancy E
Published: December 2006

The developmental and oncogenic roles of MYC proteins are well established, but the transcriptional targets mediating their functions remain elusive. Using small interfering RNA‐mediated knockdown in breast and cervix carcinoma cell lines, which overexpress c‐MYC, we show that c‐MYC independently controls metabolism and cell proliferation, and can, depending on the cells, promote or inhibit migration. We identified new c‐MYC target genes in these cell lines, and show that selective regulation of some targets correlates with the phenotypic responses of these different cell lines to c‐MYC depletion. Notably, we show that a positive regulation of the WNT signalling pathway contributes to c‐MYC pro‐mitogenic effects in breast and cervix carcinoma cells. We also show that repression of CCL5/RANTES accounts for c‐MYC anti‐migratory effects in specific breast cancer cells. Our combined genomic and phenotypic analysis indicates that c‐MYC functions are cellular‐context‐dependent and that selectively regulated genes are responsible for its differential properties.
Pin1 stabilizes Emi1 during G2 phase by preventing its association with SCFβtrcp
Authors: Bernis Cyril , Vigneron Suzanne , Burgess Andrew , Labbé Jean‐Claude , Fesquet Didier , Castro Anna , Lorca Thierry
Published: December 2006

The anaphase‐promoting complex (APC) early mitotic inhibitor 1 (Emi1) is required to induce S‐ and M‐phase entries by stimulating the accumulation of cyclin A and cyclin B through APCCdh1/cdc20 inhibition. In this report, we show that Emi1 proteolysis can be induced by cyclin A/cdk (cdk for cyclin‐dependent kinase). Paradoxically, Emi1 is stable during G2 phase, when cyclin A/cdk, Plx1 and SCFβtrcp (SCF for Skp1‐Cul1‐Fbox protein)—which play a role in its degradation—are active. Here, we identify Pin1 as a new regulator of Emi1 that induces Emi1 stabilization by preventing its association with SCFβtrcp. We show that Pin1 binds to Emi1 and prevents its association with βtrcp in an isomerization‐dependent pathway. We also show that Emi1–Pin1 binding is present in vivo in XL2 cells during G2 phase and that this association protects Emi1 from being degraded during this phase of the cell cycle. We propose that S‐ and M‐phase entries are mediated by the accumulation of cyclin A and cyclin B through a Pin1‐dependent stabilization of Emi1 during G2.