bluuebunny/crossref_metadata_2025 huggingface dataset:
Optical Diagnostics of Micro Discharge Jets
Authors: Schulz‐von der Gathen V. , Buck V. , Gans T. , Knake N. , Niemi K. , Reuter St. , Schaper L. , Winter J.
Published: November 2007

Micro plasmas operated at ambient pressure with dimensions of the confining geometry in the order of a few ten micrometers to a millimeter are actually in the focus of interest due to the broad regime of applicability they offer and due to a similarly broad range of open physical questions. Here we present optical measurements within the discharge core and the effluent region of an especially developed micro discharge jet. To get an understanding of the complex system of this discharge it is important to analyse transport phenomena of energy and particles within both parts of the discharge by various highly sophisticated diagnostics. As a consequence of the limited access and the dimensions of the micro discharge most of these diagnostics are optical. Here we present diagnostics applied to determine spatially resolved absolute atomic oxygen densities as the most reactive constituent of the effluent, density maps of ozone as final reaction product of the gas chemical chain induced by the discharge and phase resolved optical emission spectroscopy yielding insight into the excitation dynamics of the discharge. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thiazolidinediones as anti‐inflammatory and anti‐atherogenic agents
Authors: Ceriello Antonio
Published: November 2007

In the last few years, there has been increasing focus on the impact of interventions on cardiovascular outcomes in patients with type 2 diabetes. Insulin resistance and hyperglycaemia often co‐exist with a cluster of risk factors for coronary artery disease, but the underlying mechanisms leading to the development of such vascular complications are complex. The over‐production of free radicals in patients suffering from diabetes results in a state of oxidative stress, which leads to endothelial dysfunction and a greater risk of atherosclerosis. Moreover, inflammatory factors which play a critical role in atherothrombosis and plaque rupture are often found to be at elevated levels in this patient population.

Thiazolidinediones (TZDs) are now routinely used to manage glucose levels, and have been suggested to influence other cardiovascular risk factors and therefore the pathways leading to macrovascular events. Consequently, recent studies have investigated the anti‐inflammatory and anti‐atherogenic properties of TZDs. The data available up to the present time, in the context of the emerging cardiovascular outcome profiles of rosiglitazone and pioglitazone, will be discussed here. Copyright © 2007 John Wiley & Sons, Ltd.
Stereomanipulation of (η5‐1‐Arylcyclohexadienyl)iron Complexes
Authors: Anson Christopher E. , Malkov Andrei V. , Roe Caroline , Sandoe Elizabeth J. , Stephenson G. Richard
Published: November 2007

A crystallographic investigation comparing five 1‐aryl‐substituted tricarbonyl[(1–5‐η)‐cyclohexadienyl]iron(1+) salts demonstrates that introducing additional electron density on the aromatic ring increases π overlap between the arene and the cyclohexadienyl ligand, thus flattening the structures sufficiently to make available a conformation in which nucleophiles can approach the site of substitution, despite the steric blockade of o‐benzyl substituents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Proteome‐ and microarray‐based expression analysis of lymphoma cell lines identifies a p53‐centered cluster of differentially expressed proteins in mantle cell and follicular lymphoma
Authors: Weinkauf Marc , Christopeit Maximilian , Hiddemann Wolfgang , Dreyling Martin
Published: November 2007

We used a standardized electrophoresis protocol to identify differentially expressed proteins based on a sample pooling approach comparing three follicular lymphoma and three mantle cell lymphoma‐derived cell lines. One hundred and seventy‐five consistently differentially expressed proteins were identified out of more than 1600 protein spots per gel. Of these 175 protein spots, 38 of the 41 most highly expressed proteins were identified by MS analysis (MALDI‐TOF), involving different cellular programs such as DNA repair (Rad50), cell cycle control (Mad1L1), transcription (SAFB), and apoptosis (Luca‐15 protein). Expression data were confirmed by Western blot analysis of identified proteins and 2‐D gel hybridization of proteins with known overexpression (G1/S‐specific cyclin‐D1, apoptosis regulator Bcl‐2). Comparison of proteome analysis to RNA expression array data revealed only a modest correlation of RNA and protein level emphasizing the relevance of post‐translational regulation in lymphomagenesis (p = 0.36). Most interestingly, additional data bank search identified 13 out of 17 referenced proteins (76%) as members of a TP53‐dependent network of cell regulation.
The environment –A route to better management?
Authors: Dennis John
Published: November 2007

Increasing environmental awareness on the part of society as a whole has, in recent years, led to increased scrutiny of the impact of industrial and commercial activities upon the environment. Arising from the general feeling that it is ‘right’ to conserve, re‐use and recycle resources, the concept of environmental management has come increasingly to the fore. The relatively recent successes achieved during well‐known waste minimization projects such as Aire and Calder and Project Catalyst have increased the fervour with which such a management approach has been lauded, because for the first time it has become clear that ‘the environment’ does not have to be a costly ‘bolt on’ extra, but can lead to genuine financial savings and efficiency improvements. But is environmental management the cure for all ills, or is it simply part of an overall picture that needs to be set in the right context? Copyright © 1995 John Wiley & Sons, Ltd and ERP Environment.
Orthogonality‐embedded space‐time codes
Authors: Đào Dũng Ngoc , Tellambura Chintha
Published: November 2007

We present a unified construction of full‐diversity space‐time block codes (STBC) called orthogonality‐embedded space‐time (OEST) codes. Other existing STBC, including orthogonal, quasi‐orthogonal and rate‐one linear threaded algebraic space‐time (LTAST) codes, can also be derived from OEST codes. The new OEST construction is of the form${\sum} (A_k\otimes C_k + B_k\otimes C_k^{\rm H})$, whereAkandBkare linear‐dispersion matrices of orthogonal STBC andCks are circulant matrices. The circulant matrices encode the data vectors, which can be completely separately detected at the receiver, greatly reducing the decoding complexity. For the same number of transmit antennas, several variants of OEST codes can be constructed allowing a tradeoff among the rate, performance and decoding complexity. A new rate‐one STBC derived from OEST codes, called semi‐orthogonal algebraic space‐time codes, is shown to achieve near capacity of multi‐input single‐output channels and performs better than several existing STBC. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of adobe wall composition at the Chaves‐Hummingbird Site, New Mexico, by diffuse reflectance spectrophotometry
Authors: Balsam William , Deaton Bobby , Adler Michael
Published: November 2007

This article investigates adobe wall construction materials utilized by prehistoric inhabitants of Chaves‐Hummingbird Pueblo, an ancestral Pueblo village located ˜20 miles west of Albuquerque, New Mexico. The walls were constructed with native clay‐rich soils some time between approximately 1275–1450 A.D. Samples were analyzed with a diffuse reflectance spectrophotometer from the near ultraviolet (NUV) through the visible (VIS) and into the near infrared (NIR) region of the electromagnetic spectrum. Cluster analysis of samples from 275 adobe walls and 36 soil locations surrounding the pueblo room blocks indicates four clusters. Comparison of typical samples from the four clusters indicates that they are very similar and are distinguished by minor variations in the three primary spectrally determined components, Na‐Ca montmorillonite, bentonite, and goethite. In general, clusters correspond with room construction episodes that are discernible through patterns of wall bonding and abutment recorded during the archaeological investigation of the site. This suggests that during different phases of construction the source of the wall adobe changed. Many of the soil samples are included in wall clusters and therefore reveal a potential source of material used for adobe, adjacent soils. However, not all the soil surrounding the pueblo grouped with wall clusters indicating a preference for certain soil types and that some soils were probably unsuitable for making adobe. Therefore, diversity in spectrally identified construction materials provides insights into source locations and possible construction preferences of the site inhabitants. © 2007 Wiley Periodicals, Inc.
Visual target modulation of functional connectivity networks revealed by self‐organizing group ICA
Authors: van de Ven Vincent , Bledowski Christoph , Prvulovic David , Goebel Rainer , Formisano Elia , Di Salle Francesco , Linden David E.J. , Esposito Fabrizio
Published: November 2007

We applied a data‐driven analysis based on self‐organizing group independent component analysis (sogICA) to fMRI data from a three‐stimulus visual oddball task. SogICA is particularly suited to the investigation of the underlying functional connectivity and does not rely on a predefined model of the experiment, which overcomes some of the limitations of hypothesis‐driven analysis. Unlike most previous applications of ICA in functional imaging, our approach allows the analysis of the data at the group level, which is of particular interest in high order cognitive studies. SogICA is based on the hierarchical clustering of spatially similar independent components, derived from single subject decompositions. We identified four main clusters of components, centered on the posterior cingulate, bilateral insula, bilateral prefrontal cortex, and right posterior parietal and prefrontal cortex, consistently across all participants. Post hoc comparison of time courses revealed that insula, prefrontal cortex and right fronto‐parietal components showed higher activity for targets than for distractors. Activation for distractors was higher in the posterior cingulate cortex, where deactivation was observed for targets. While our results conform to previous neuroimaging studies, they also complement conventional results by showing functional connectivity networks with unique contributions to the task that were consistent across subjects. SogICA can thus be used to probe functional networks of active cognitive tasks at the group‐level and can provide additional insights to generate new hypotheses for further study. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.
Discrete dynamic Bayesian network analysis of fMRI data
Authors: Burge John , Lane Terran , Link Hamilton , Qiu Shibin , Clark Vincent P.
Published: November 2007

We examine the efficacy of using discrete Dynamic Bayesian Networks (dDBNs), a data‐driven modeling technique employed in machine learning, to identify functional correlations among neuroanatomical regions of interest. Unlike many neuroimaging analysis techniques, this method is not limited by linear and/or Gaussian noise assumptions. It achieves this by modeling the time series of neuroanatomical regions as discrete, as opposed to continuous, random variables with multinomial distributions. We demonstrated this method using an fMRI dataset collected from healthy and demented elderly subjects (Buckner, et al., 2000: J Cogn Neurosci 12:24‐34) and identify correlates based on a diagnosis of dementia. The results are validated in three ways. First, the elicited correlates are shown to be robust over leave‐one‐out cross‐validation and, via a Fourier bootstrapping method, that they were not likely due to random chance. Second, the dDBNs identified correlates that would be expected given the experimental paradigm. Third, the dDBN's ability to predict dementia is competitive with two commonly employed machine‐learning classifiers: the support vector machine and the Gaussian naïve Bayesian network. We also verify that the dDBN selects correlates based on non‐linear criteria. Finally, we provide a brief analysis of the correlates elicited from Buckner et al.'s data that suggests that demented elderly subjects have reduced involvement of entorhinal and occipital cortex and greater involvement of the parietal lobe and amygdala in brain activity compared with healthy elderly (as measured via functional correlations among BOLD measurements). Limitations and extensions to the dDBN method are discussed. Hum Brain Mapp, 2009. © 2007 Wiley‐Liss, Inc.
The influence of ageing on complex brain networks: A graph theoretical analysis
Authors: Micheloyannis Sifis , Vourkas Michael , Tsirka Vassiliki , Karakonstantaki Eleni , Kanatsouli Kassia , Stam Cornelis J.
Published: November 2007

Objective:

To determine the functional connectivity of different EEG bands at the “baseline” situation (rest) and during mathematical thinking in children and young adults to study the maturation effect on brain networks at rest and during a cognitive task.

Methods:

Twenty children (8–12 years) and twenty students (21–26 years) were studied. The synchronization likelihood was used to evaluate the interregional synchronization of different EEG frequency bands in children and adults, at rest and during math. Then, graphs were constructed and characterized in terms of local structure (clustering coefficient) and overall integration (path length) and the “optimal” organization of the connectivity i.e., the small world network (SWN).

Results:

The main findings were: (i) Enhanced synchronization for theta band during math more prominent in adults. (ii) Decrease of the optimal SWN organization of the alpha2 band during math. (iii) The beta and especially gamma bands showed lower synchronization and signs of lower SWN organization in both situations in adults.

Conclusion:

There are interesting findings related to the two age groups and the two situations. The theta band showed higher synchronization during math in adults as a result of higher capacity of the working memory in this age group. The alpha2 band showed some SWN disorganization during math, a process analog to the known desynchronization. In adults, a dramatic reduction of the connections in gray matter occurs. Although this maturation process is probably related to higher efficiency, reduced connectivity is expressed by lower synchronization and lower mean values of the graph parameters in adults. Hum Brain Mapp 2009. © 2007 Wiley‐Liss, Inc.
Do nutrition labels improve dietary outcomes?
Authors: Variyam Jayachandran N.
Published: November 2007

The disclosure of nutritional characteristics of most packaged foods became mandatory in the United States with the implementation of the Nutrition Labeling and Education Act (NLEA) in 1994. Under the NLEA regulations, a ‘Nutrition Facts’ panel displays information on nutrients such as calories, total and saturated fats, cholesterol, and sodium in a standardized format. By providing nutrition information in a credible, distinctive, and easy‐to‐read format, the new label was expected to help consumers choose healthier, more nutritious diets. This paper examines whether the disclosure of nutrition information through the mandatory labels impacted consumer diets. Assessing the dietary effects of labeling is problematic due to the confounding of the label effect with unobserved label user characteristics. This self‐selection problem is addressed by exploiting the fact that the NLEA exempts away‐from‐home foods from mandatory labeling. Difference‐in‐differences models that account for zero away‐from‐home intakes suggest that the labels increase fiber and iron intakes of label users compared with label nonusers. In comparison, a model that does not account for self‐selection implies significant label effects for all but two of the 13 nutrients that are listed on the label. Published in 2007 by John Wiley & Sons, Ltd.
Lack of functional erythropoietin receptors of cancer cell lines
Authors: Laugsch Magdalena , Metzen Eric , Svensson Tanja , Depping Reinhard , Jelkmann Wolfgang
Published: November 2007

Erythropoietin (Epo) therapy reduces red cell transfusion requirements and improves the quality of life of anemic cancer patients receiving chemotherapy. However, there is concern that Epo may promote tumor growth. We investigated by real‐time RT‐PCR, immunofluorescence microscopy, Western blotting and cell growth analysis whether human cancer cell lines (SH‐SY5Y, MCF7, HepG2, U2‐OS, HeLa, HEK293T, RCC4, HCT116, 7860wt and SW480) possess functional Epo receptors (EpoR). We detected EpoR mRNA in all cell lines. Neither hypoxia nor Epo treatment altered the level of EpoR mRNA expression. Four commonly used commercial antibodies proved to be unsuitable for immunoblot procedures because they cross‐reacted with several proteins unrelated with EpoR. Depending on the antibody used, EpoR was localized to the plasma membrane, the cytoplasm or the nucleus. Experiments with small interfering RNA showed that EpoR protein was not expressed by the tumor cells except by UT7/Epo leukemia cells, which served as an EpoR positive control line, and by cells transfected with the human EpoR gene. Apart from UT7/Epo, none of the tumor cell lines responded to Epo treatment with phosphorylation of signaling molecules or with cell proliferation. © 2007 Wiley‐Liss, Inc.
Trends in oesophageal cancer incidence and mortality in Europe
Authors: Bosetti Cristina , Levi Fabio , Ferlay Jacques , Garavello Werner , Lucchini Franca , Bertuccio Paola , Negri Eva , Vecchia Carlo La
Published: November 2007

To monitor recent trends in mortality from oesophageal cancer in 33 European countries, we analyzed the data provided by the World Health Organization over the last 2 decades, using also joinpoint regression. For selected European cancer registration areas, we also analyzed incidence rates for different histological types. For men in the European Union (EU), age‐standardized (world population) mortality rates were stable around 6/100,000 between the early 1980s and the early 1990s, and slightly declined in the last decade (5.4/100,000 in the early 2000s, annual percent change, APC = −1.1%). In several western European countries, male rates have started to level off or decline during the last decade (APC = −3.4% in France, and −3.0% in Italy). Also in Spain and the UK, which showed upward trends in the 1990s, the rates tended to level off in most recent years. A levelling of rates was observed only more recently in countries of central and eastern Europe, which had had substantial rises up to the late 1990s. Oesophageal cancer mortality rates remained comparatively low in European women, and overall EU female rates were stable around 1.1–1.2/100,000 over the last 2 decades (APC = −0.1%). In northern Europe a clear upward trend was observed in the incidence of oesophageal adenocarcinoma, and in Denmark and Scotland incidence of adenocarcinoma in men is now higher than that of squamous‐cell carcinoma. Squamous‐cell carcinoma remained the prevalent histological type in southern Europe. Changes in smoking habits and alcohol drinking for men, and perhaps nutrition, diet and physical activity for both sexes, can partly or largely explain these trends. © 2007 Wiley‐Liss, Inc.
The interactive relationship of competitive climate and trait competitiveness with workplace attitudes, stress, and performance
Authors: Fletcher Thomas D. , Major Debra A. , Davis Donald D.
Published: November 2007

There has been a considerable debate about the individual and organizational benefits of competition. Adopting a person–environment fit perspective, this research examined the influence of competition as an interaction between trait competitiveness and competitive climate. Using a sample of information technology workers, competitive climate was considered as both an individual level variable and a workgroup variable. Results show that the effect of competitive climate depended on trait competitiveness and the level at which climate was assessed for four of the outcomes assessed: job satisfaction, organizational commitment, job dedication, and supervisor‐rated task performance. In general, the effect of competitive climate was more negative for individuals lower in trait competitiveness. Competitive psychological climate was associated with greater stress regardless of the level of trait competitiveness but was not directly related to self‐rated task performance. Findings suggest that managers should be cautious in encouraging competitive climate. Copyright © 2007 John Wiley & Sons, Ltd.
Toward a unified theory of consumer acceptance technology
Authors: Kulviwat Songpol , Bruner II Gordon C. , Kumar Anand , Nasco Suzanne A. , Clark Terry
Published: November 2007

In the last few decades, scholars and practitioners have increasingly tried to understand the factors that influence technology acceptance. Theories and models developed by scholars have tended to focus on the role of cognition and have rarely included affect. The few studies that have incorporated affect have tended to measure a single emotion rather than modeling it comprehensively. This research addresses that inadequacy in our understanding of technology adoption by merging two previously unrelated models: TAM (the Technology Acceptance Model) and PAD (the Pleasure, Arousal, and Dominance paradigm of affect). This study also examines an enhanced view of cognition. The product of this unified theoretical framework is referred to as the Consumer Acceptance of Technology (CAT) model. The results of a test using structural equation modeling provide empirical support for the model. Overall, the CAT model explains over 50% of the variance in consumer adoption intentions, a considerable increase compared to TAM. These findings suggest that substantial improvement in the prediction of technology adoption decisions is possible by use of this model with its integration of affect and cognition. © 2007 Wiley Periodicals, Inc.
Tissue and organ donation for research in forensic pathology: the MRC Sudden Death Brain and Tissue Bank
Authors: Millar T , Walker R , Arango J‐C , Ironside JW , Harrison DJ , MacIntyre DJ , Blackwood D , Smith C , Bell JE
Published: November 2007

Novel methodological approaches to the investigation of brain and non‐central nervous system disorders have led to increased demand for well‐characterized, high quality human tissue samples, particularly from control cases. In the setting of the new Human Tissue legislation, we sought to determine whether relatives who have been suddenly bereaved are willing to grant authorization for research use of post mortem tissue samples and organs in sufficient numbers to support the establishment of a brain and tissue bank based in the forensic service. Research authorization was sought from families on the day prior to forensic post mortem examination followed up by written confirmation. We have to date selected individuals who have died suddenly (age range 1–89 years) and who were likely to have normal brains or who had displayed symptoms of a CNS disorder of interest to researchers, including psychiatric disorders. One hundred and eleven families have been approached during the first 2 years of this project. Research use of tissue samples was authorized by 96% of families and 17% agreed to whole brain donation. Audit of families' experience does not suggest that they are further distressed by being approached. Respondents expressed a clear view that the opportunity for research donation should be open to all bereaved families. Despite the sometimes long post mortem intervals, the quality of tissue samples is good, as assessed by a range of markers including Agilent BioAnalyzer quantification of RNA integrity (mean value 6.4). We conclude that the vast majority of families are willing to support research use of post mortem tissues even in the context of sudden bereavement and despite previous adverse publicity. The potential for acquisition of normal CNS and non‐CNS tissues and of various hard‐to‐get CNS disorders suggests that efforts to access the forensic post mortem service for research material are eminently worthwhile. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Digit ratio (2D:4D) and Cattell's personality traits
Authors: Lindová Jitka , Hrušková Martina , Pivoňková Věra , Kuběna Aleš , Flegr Jaroslav
Published: November 2007

The ratio between second and fourth finger (2D:4D) is sexually dimorphic; it is lower in men than in women. Studies using broad personality domains yielded correlations of 2D:4D with neuroticism, extraversion or agreeableness, but the obtained results have been inconsistent. We correlated 2D:4D of 184 women and 101 men with their scores in Cattell's 16 Personality Factor (16PF) Questionnaire. We found women with a higher (more ‘feminine’) right hand 2D:4D to score lower in emotional stability and social boldness and higher in privateness. Mediator analysis showed emotional stability to be probably primarily correlated with 2D:4D and to act as a mediator between 2D:4D and social boldness. Privateness appears to be mediated by an even more complex path. We discuss the usefulness of primary‐level personality questionnaires and mediator analyses in the investigation of psycho‐morphological associations. Copyright © 2007 John Wiley & Sons, Ltd.
Scaling‐up technique for net ecosystem productivity of deciduous broadleaved forests in Japan using MODIS data
Authors: Yamaji Takehiko , Sakai Toru , Endo Takahiro , Baruah Pranab J. , Akiyama Tsuyoshi , Saigusa Nobuko , Nakai Yuichiro , Kitamura Kenzo , Ishizuka Moriyoshi , Yasuoka Yoshifumi
Published: November 2007

We attempted to obtain carbon sequestration maps of deciduous forests in Japan using detectable parameters from the Moderate Resolution Imaging Spectrometer (MODIS) sensor and to determine how the spatial pattern of carbon sequestration differs within the same forest ecosystem type. For this investigation, we firstly parameterized the MODIS algorithm at one flux tower site, Takayama, for the years 2002–2003. The MODIS algorithm could link flux‐based net ecosystem productivity (NEP) with simple functions controlled by a thermal infrared band and a vegetation index. Second, the performance of the MODIS algorithm was validated through comparisons with the flux‐based NEP at another flux tower site, Hitsujigaoka. The MODIS‐based NEP at Hitsujigaoka was also within an accuracy of a flux‐based NEP with R2 of 0.879 and root mean square error of 1.64 gC m−2 day−1, regardless of canopy structure and age. The MODIS algorithm was noteworthy for its general applicability in different locations. Finally, we used the MODIS algorithm for the same forest ecosystem type in Japan for regional extrapolation of NEP. The MODIS‐based NEP of deciduous forests in Japan showed great variance with 347 ± 288 gC m−2 year−1 in 2002, according to the stand structure and climatic condition of the year. Studies for quantification of ecosystem carbon balance need to consider variance, frequency and spatial distributions of NEP. Satellite remote sensing demonstrated the potential for the large‐scale mapping of NEP.
Solar wind dynamic pressure forced oscillation of the magnetosphere‐ionosphere coupling system: A numerical simulation of directly pressure‐forced geomagnetic pulsations
Authors: Motoba Tetsuo , Fujita Shigeru , Kikuchi Takashi , Tanaka Takashi
Published: November 2007

We have investigated dynamical effects of an oscillating solar wind dynamic pressure (Psw) on the magnetosphere‐ionosphere (M‐I) system using a global magnetohydrodynamic (MHD) numerical simulation. We find that a directly Psw‐forced pulsation on the ground is strongly controlled by the Psw‐induced plasma convection patterns in the M‐I system and the associated three‐dimensional current system. When a sinusoidal Psw oscillation with 10‐min period is applied over the magnetosphere, it forces the magnetosphere to oscillate in the same manner. As the magnetosphere undergoes gradual compressed (expanded) state, a twin‐vortex flow with clockwise (counterclockwise) in the morning and counterclockwise (clockwise) in the afternoon is excited well inside the dayside magnetosphere and then develops into large‐scale vortices with a slow tailward motion. Each developed twin‐vortex flow pattern in the magnetosphere is mapped to the polar ionosphere via a pair of field‐aligned currents (FACs), one flowing into (out of) the morning ionosphere and the other out of (into) the afternoon. Spatial and temporal variations of the oscillating ionospheric twin‐vortex flows result in a global geomagnetic pulsation activity with a latitude‐independent period at high latitudes. The major period of the global geomagnetic pulsation period matches that of the Psw oscillation. In either state, the main dynamo (J · E < 0) supplying the electromagnetic energy to the ionosphere via FACs is found to be driven by Psw‐induced plasma flows across high‐pressure regions around the magnetospheric cusp and in the dawnside/duskside equatorial plane. Our simulation indicates that, the ionospheric flow and FAC patterns in the compressed and expanded states of the magnetosphere are nearly mirror images of each other, while the dynamo regions and the three‐dimensional current configurations in the magnetosphere do not always appear as mirror images.
El Niño Modoki and its possible teleconnection
Authors: Ashok Karumuri , Behera Swadhin K. , Rao Suryachandra A. , Weng Hengyi , Yamagata Toshio
Published: November 2007

Using observed data sets mainly for the period 1979–2005, we find that anomalous warming events different from conventional El Niño events occur in the central equatorial Pacific. This unique warming in the central equatorial Pacific associated with a horseshoe pattern is flanked by a colder sea surface temperature anomaly (SSTA) on both sides along the equator. empirical orthogonal function (EOF) analysis of monthly tropical Pacific SSTA shows that these events are represented by the second mode that explains 12% of the variance. Since a majority of such events are not part of El Niño evolution, the phenomenon is named as El Niño Modoki (pseudo‐El Niño) (“Modoki” is a classical Japanese word, which means “a similar but different thing”). The El Niño Modoki involves ocean‐atmosphere coupled processes which include a unique tripolar sea level pressure pattern during the evolution, analogous to the Southern Oscillation in the case of El Niño. Hence the total entity is named as El Niño–Southern Oscillation (ENSO) Modoki. The ENSO Modoki events significantly influence the temperature and precipitation over many parts of the globe. Depending on the season, the impacts over regions such as the Far East including Japan, New Zealand, western coast of United States, etc., are opposite to those of the conventional ENSO. The difference maps between the two periods of 1979–2004 and 1958–1978 for various oceanic/atmospheric variables suggest that the recent weakening of equatorial easterlies related to weakened zonal sea surface temperature gradient led to more flattening of the thermocline. This appears to be a cause of more frequent and persistent occurrence of the ENSO Modoki event during recent decades.
A variable and decreasing sink for atmospheric CO2 in the North Atlantic
Authors: Schuster Ute , Watson Andrew J.
Published: November 2007

A time series of observations from merchant ships between the U.K. and the Caribbean is used to establish the variability of sea surface pCO2 and air‐to‐sea flux from the mid‐1990s to early 2000s. We show that the sink for atmospheric CO2 exhibits important interannual variability, which is in phase across large regions from year to year. Additionally, there has been an interdecadal decline, evident throughout the study region but especially significant in the northeast of the area covered, with the sink reducing >50% from the mid‐1990s to the period 2002–2005. A review of available observations suggests a large region of decrease covering much of the North Atlantic but excluding the western subtropical areas. We estimate that the uptake of the region between 20°N and 65°N declined by ∼0.24 Pg C a−1 from 1994/1995 to 2002–2005. Declining rates of wintertime mixing and ventilation between surface and subsurface waters due to increasing stratification, linked to variation in the North Atlantic Oscillation, are suggested as the main cause of the change. These are exacerbated by a contribution from the changing buffer capacity of the ocean water, as the carbon content of surface waters increases.
Dicarboxylic acids, ketocarboxylic acids, and dicarbonyls in the urban atmosphere of China
Authors: Ho K. F. , Cao J. J. , Lee S. C. , Kawamura Kimitaka , Zhang R. J. , Chow Judith C. , Watson John G.
Published: November 2007

PM2.5 samples from 14 Chinese cities during winter and summer of 2003 were analyzed for 29 water‐soluble organic species including diacids, ketoacids and dicarbonyls using a capillary GC and GC/MS. Homologous series of α,ω‐dicarboxylic acids (C2–C12) and ω‐oxocarboxylic acids (C2–C9) were detected as well as aromatic (phthalic) acid, α‐ketoacid (pyruvic acid) and α‐dicarbonyls (C2–C3). Molecular distributions of diacids demonstrated that oxalic (C2) acid was the most abundant species followed by C3 or C4 diacids. Higher carbon number diacids were less abundant. C2 diacid constituted 42–74% of total diacids (211–2162 ng m−3), corresponding to 0.15–2.83% of PM2.5 mass. In winter, the highest concentrations were observed in the southern city of Guangzhou (1886 ng m−3), while the lowest concentrations were observed in the northwest city of Jinchang (388 ng m−3). In summer, the highest concentrations were found in the northern city of Beijing (1598 ng m−3), whereas the lowest concentrations were found in Jinchang (223 ng m−3). Spatial variations of water‐soluble diacids were characterized by higher concentrations in the south and lower concentrations in the north during winter whereas highest concentrations were observed in the north and midwest during summer. These spatial and seasonal distributions are consistent with photochemical production and the subsequent accumulation under different meteorological conditions.
Recent changes in nitrate and dissolved organic carbon export from the upper Kuparuk River, North Slope, Alaska
Authors: McClelland J. W. , Stieglitz M. , Pan Feifei , Holmes R. M. , Peterson B. J.
Published: November 2007

Export of nitrate and dissolved organic carbon (DOC) from the upper Kuparuk River between the late 1970s and early 2000s was evaluated using long‐term ecological research (LTER) data in combination with solute flux and catchment hydrology models. The USGS Load Estimator (LOADEST) was used to calculate June–August export from 1978 forward. LOADEST was then coupled with a catchment‐based land surface model (CLSM) to estimate total annual export from 1991 to 2001. Simulations using the LOADEST/CLSM combination indicate that annual nitrate export from the upper Kuparuk River increased by ∼5 fold and annual DOC export decreased by about one half from 1991 to 2001. The decrease in DOC export was focused in May and was primarily attributed to a decrease in river discharge. In contrast, increased nitrate export was evident from May to September and was primarily attributed to increased nitrate concentrations. Increased nitrate concentrations are evident across a wide range of discharge conditions, indicating that higher values do not simply reflect lower discharge in recent years but a significant shift to higher concentration per unit discharge. Nitrate concentrations remained elevated after 2001. However, extraordinarily low discharge during June 2004 and June–August 2005 outweighed the influence of higher concentrations in determining export during these years. The mechanism responsible for the recent increase in nitrate concentrations is uncertain but may relate to changes in soils and vegetation associated with regional warming. While changes in nitrate and DOC export from arctic rivers reflect changes in terrestrial ecosystems, they also have significant implications for Arctic Ocean ecosystems.
Coupling of millennial‐scale changes in sea surface temperature and precipitation off northeastern Brazil with high‐latitude climate shifts during the last glacial period
Authors: Jaeschke Andrea , Rühlemann Carsten , Arz Helge , Heil Gerrit , Lohmann Gerrit
Published: November 2007

High‐resolution records of alkenone‐derived sea surface temperatures and elemental Ti/Ca ratios from a sediment core retrieved off northeastern Brazil (4°S) reveal short‐term climate variability throughout the past 63,000 a. Large pulses of terrigenous sediment discharge, caused by increased precipitation in the Brazilian hinterland, coincide with Heinrich events and the Younger Dryas period. Terrigenous input maxima related to Heinrich events H6–H2 are characterized by rapid cooling of surface water ranging between 0.5° and 2°C. This signature is consistent with a climate model experiment where a reduction of the Atlantic meridional overturning circulation (AMOC) and related North Atlantic cooling causes intensification of NE trade winds and a southward movement of the Intertropical Convergence Zone, resulting in enhanced precipitation off northeastern Brazil. During deglaciation the surface temperature evolution at the core site predominantly followed the Antarctic warming trend, including a cooling, prior to the Younger Dryas period. An abrupt temperature rise preceding the onset of the Bølling/Allerød transition agrees with model experiments suggesting a Southern Hemisphere origin for the abrupt resumption of the AMOC during deglaciation caused by Southern Ocean warming and associated with northward flow anomalies of the South Atlantic western boundary current.
Viscous relaxation on early Mars: A study of ancient impact basins
Authors: Mohit P. Surdas , Phillips Roger J.
Published: November 2007

The improved resolution of recent global models of the gravity field of Mars enables an investigation of the crustal structure of large Martian impact basins. The results reveal that almost all basins between 275–1000 km in diameter show very shallow depths and limited crustal thinning for their size. We also show evidence that Martian basins once had lunar mascon‐like gravity highs. We demonstrate that it is unlikely that surface processes alone are responsible for the current state of Martian basins and propose that viscous relaxation of relief by lower crustal flow was the dominant process in modifying Martian basins early in the planet's history. Viscoelastic modeling suggests that the current surface topography and crustal structure of these basins are consistent with this hypothesis. The heat flows required to produce relaxation (>47–55 mW m−2) are in good agreement with previous geophysical constraints on early Martian thermal evolution.
Radar‐derived bed roughness characterization of Institute and Möller ice streams, West Antarctica, and comparison with Siple Coast ice streams
Authors: Bingham Robert G. , Siegert Martin J.
Published: November 2007

Subglacial bed conditions exert a significant control on ice stream behavior and evolution, and can be characterized by determining bed roughness from FFT analysis of radar‐imaged basal reflectors. Here we assess bed roughness across Institute and Möller ice streams, West Antarctica, and compare our findings with bed roughness determined across the Siple Coast ice streams. We find that variations in bed roughness are spatially organized, and attribute this to the varying efficacy of subglacial erosion and deposition, with rougher (inland, slow‐flowing) regions largely manifesting preglacial topography, and smoother (downstream, fast‐flowing) regions evincing significant postglacial modification to the subglacial landscape. The observed similarities between bed roughness characteristics of IIS/MIS and the Siple ice streams suggest that IIS and MIS are largely underlain by wet, poorly consolidated sediments, and may therefore be vulnerable to the types of dynamical instabilities experienced by the Siple ice streams.
Effect of mineral dust aerosols on the photolysis rates in the clean and polluted marine environments
Authors: Jeong Gill‐Ran , Sokolik Irina N.
Published: November 2007

This study examines the importance of spectral optical properties of mineral dust in calculations of photolysis rates in clean and polluted marine environments. A set of optical characteristics was computed with Mie theory using data on the size distribution and composition of mineral dust from recent experimental and modeling studies. These models were incorporated into the National Center for Atmospheric Research tropospheric ultraviolet‐visible radiation transfer code. The 13 analyzed photolysis reactions were classified into three groups according to their photolytic wavelengths and the vertical profile of J values in the aerosol‐free atmosphere. The photolysis reactions of O3(O1D), NO2, and NO3(NO) were selected as representative of groups I, II, and III, respectively. We find that depending on its properties, dust causes either a decrease or an increase in the spectral actinic fluxes relative to the aerosol‐free condition. The wavelength range in which the changes in actinic fluxes are negative becomes broader as the amount of dust load increases, a dust size distribution is shifted to coarse size mode, and the iron oxide content in dust aggregates increases. Changes in actinic fluxes also depend on the sun position (time of the day) and an altitude considered. As a result, dust exerts the differing impact on J values of the three photolytic groups. The diurnal cycle of dust‐affected J values of a given group is similar among the differing size distribution and dust compositions, but changes in J values vary by a factor of 1.5–2. For a given content of iron oxide, the largest changes are caused by the size distributions that are shifted to the fine size mode. A change in J values of groups I and II caused by the varying amount of iron oxide in dust aggregates (from 1% to 10%) is negative in and below the dust layer. In contrast, J values of group III increase in the presence of low absorbing dust (with 1% of iron oxide), but they decrease with increasing dust absorption. Our results indicate that the dust composition not only will be needed to accurately model a decrease in J values of groups I and II but also to determine a correct sign and value of changes of J values of group III. In the case of dust mixed with pollution, we find that the external mixing of dust and black carbon causes somewhat larger changes in J values compared to the internal mixing of these species. We conclude that regional differences in size and composition of mineral dust as well as related changes in the vertical profile and diurnal cycle of actinic fluxes and J values should be taken into account if more realistic assessments of the dust impact on photochemistry through photolysis are to be achieved.
Steady‐state plasma transition in the Venus ionosheath
Authors: Pérez‐de‐Tejada H. , Intriligator D. S. , Strangeway R. J.
Published: November 2007

The results of an extended analysis of the plasma and electric field data of the Pioneer Venus Orbiter (PVO) are presented. We report the persistent presence of a plasma transition embedded in the flanks of the Venus ionosheath between the bow shock and the ionopause. This transition is identified by the repeated presence of characteristic bursts in the 30 kHz channel of the electric field detector of the PVO. The observed electric field signals coincide with the onset of different plasma conditions in the inner ionosheath where more rarified plasma fluxes are measured. The repeated identification of this intermediate ionosheath transition in the PVO data indicates that it is present as a steady state feature of the Venus plasma environment. The distribution of PVO orbits in which the transition is observed suggests that it is more favourably detected in the vicinity of and downstream from the terminator.
Prolactin stimulates cell proliferation through a long form of prolactin receptor and K+ channel activation
Authors: VAN COPPENOLLE Fabien , SKRYMA Roman , OUADID-AHIDOUCH Halima , SLOMIANNY Christian , ROUDBARAKI Morad , DELCOURT Philippe , DEWAILLY Etienne , HUMEZ Sandrine , CRÉPIN Alexandre , GOURDOU Isabelle , DJIANE Jean , BONNAL Jean-Louis , MAUROY Brigitte , PREVARSKAYA Natalia
Published: November 2007

PRL (prolactin) has been implicated in the proliferation and differentiation of numerous tissues, including the prostate gland. However, the PRL-R (PRL receptor) signal transduction pathway, leading to the stimulation of cell proliferation, remains unclear and has yet to be mapped. The present study was undertaken to develop a clear understanding of the mechanisms involved in this pathway and, in particular, to determine the role of K+ channels. We used androgen-sensitive prostate cancer (LNCaP) cells whose proliferation is known to be stimulated by PRL. Reverse transcriptase PCR analysis showed that LNCaP cells express a long form of PRL-R, but do not produce its intermediate isoform. Patch-clamp techniques showed that the application of 5 nM PRL increased both the macroscopic K+ current amplitude and the single K+-channel open probability. This single-channel activity increase was reduced by the tyrosine kinase inhibitors genistein, herbimycin A and lavandustine A, thereby indicating that tyrosine kinase phosphorylation is required in PRL-induced K+ channel stimulation. PRL enhances p59fyn phosphorylation by a factor of 2 after a 10 min application in culture. In addition, where an antip59fyn antibody is present in the patch pipette, PRL no longer increases K+ current amplitude. Furthermore, the PRL-stimulated proliferation is inhibited by the K+ channel inhibitors α-dendrotoxin and tetraethylammonium. Thus, as K+ channels are known to be involved in LNCaP cell proliferation, we suggest that K+ channel modulation by PRL, via p59fyn pathway, is the primary ionic event in PRL signal transduction, triggering cell proliferation.
Functional reconstitution, gene isolation and topology modelling of porins from Burkholderia pseudomallei and Burkholderia thailandensis
Authors: SIRITAPETAWEE Jaruwan , PRINZ Heino , SAMOSORNSUK Worada , ASHLEY Richard H. , SUGINTA Wipa
Published: November 2007

The intracellular pathogen Burkholderia pseudomallei is the causative agent of tropical melioidosis, and Burkholderia thailandensis is a closely-related Gram-negative bacterium that does not cause serious disease. Like other bacteria, the major outer membrane (OM) porins of Burkholderia strains, BpsOmp38 and BthOmp38 may have roles in antibiotic resistance and immunity. We purified both proteins and found them to be immunologically related, SDS-resistant, heat-sensitive trimers with Mr of approx. 110000. In functional liposome-swelling assays, both proteins showed similar permeabilities for small sugar molecules, compatible with a pore diameter of between 1.2 and 1.6 nm. Secondary structure analysis by FTIR (Fourier-transform infrared) spectroscopy revealed almost identical spectra with predominantly β-sheet structures, typical of bacterial porins. MALDI–TOF (matrix-assisted laser-desorption ionization–time of flight) MS and ESI/MS (electrospray ionization MS) analysis of each protein showed extensive sequence similarities to the OpcP1 porin from Burkholderia cepacia (later found to be 76.5% identical). Based on information from the incomplete B. pseudomallei genome-sequencing project, the genes encoding Omp38 were identified and amplified by PCR from B. pseudomallei and B. thailandensis genomic DNA. The nucleotide sequences are 99.7% identical, and the predicted processed proteins are 100% identical. Topology prediction and molecular modelling suggest that this newly-isolated and cloned porin is a 16-stranded β-barrel and the external loops of the protein could be important determinants of the immune response to infection.