bluuebunny/crossref_metadata_2025 huggingface dataset:
Genome‐wide DNA methylation profiling
Authors: Bibikova Marina , Fan Jian‐Bing
Published: September 2009

DNA methylation plays a critical role in the regulation of gene expression. The ability to access the methylation status for a large number of genes or the entire genome should greatly facilitate the understanding of the nature of gene regulation in cells, and epigenetic mechanism of interactions between cells and environment. Microarray and sequencing‐based DNA methylation profiling technologies have been developed to meet this goal. These methods can be categorized into three main classes based on how the methylation status is interrogated: discrimination of bisulfite induced C to T transition; cleavage of genomic DNA by methylation‐sensitive restriction enzymes; and immunoprecipitation with methyl‐binding protein or antibodies against methylated cytosines. With the development of next‐generation sequencing technologies, genome‐wide bisulfite sequencing has become a reality. Either whole‐ or reduced‐genome approaches have been used to get the most comprehensive DNA methylation profiles in organisms of various genome sizes. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Laboratory Methods and Technologies > Genetic/Genomic Methods
Toward a VPH/Physiome ToolKit
Authors: Garny Alan , Cooper Jonathan , Hunter Peter J.
Published: September 2009

The Physiome Project was officially launched in 1997 and has since brought together teams from around the world to work on the development of a computational framework for the modeling of the human body. At the European level, this effort is focused around patient‐specific solutions and is known as the Virtual Physiological Human (VPH) Initiative.

Such modeling is both multiscale (in space and time) and multiphysics. This, therefore, requires careful interaction and collaboration between the teams involved in the VPH/Physiome effort, if we are to produce computer models that are not only quantitative, but also integrative and predictive.

In that context, several technologies and solutions are already available, developed both by groups involved in the VPH/Physiome effort, and by others. They address areas such as data handling/fusion, markup languages, model repositories, ontologies, tools (for simulation, imaging, data fitting, etc.), as well as grid, middleware, and workflow.

Here, we provide an overview of resources that should be considered for inclusion in the VPH/Physiome ToolKit (i.e., the set of tools that addresses the needs and requirements of the Physiome Project and VPH Initiative) and discuss some of the challenges that we are still facing. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Analytical and Computational Methods > Dynamical Methods

Models of Systems Properties and Processes > Organismal Models

Physiology > Physiology of Model Organisms

Translational, Genomic, and Systems Medicine > Translational Medicine
Complement and Neutrophil Function Changes After Liver Resection in Humans
Authors: Strey Christoph Werner , Siegmund Britta , Rosenblum Saskia , Marquez‐Pinilla Rosa Maria , Oppermann Elsie , Huber‐Lang Markus , Lambris John D. , Bechstein Wolf O.
Published: September 2009

Background

Complement activation contributes to the regulation of liver regeneration after liver resection (LR) in mice.

Methods

We hypothesized that complement activation and changes in C5a‐receptors (C5aR, C5L2) on polymorphonuclear cells (PMN) and monocytes are important in clinical LR. Anaphylatoxin and C5b9 plasma levels were measured (bead‐array, ELISA) (25 patients) and receptor expression was assessed after LR (19 patients) (FACS). In vitro PMN C5a‐dependent chemotactic response (7 patients) as well as l‐selectin shedding and Mac‐1 expression (3 patients) was determined.

Results

C3a increased after LR (31.1 ± 4 before LR vs. 41.6 ± 5 ng/ml, 30 min after LR, P < 0.01), as did C5b9 (12.7 ± 1 before LR vs. 26.9 ± 3 ng/ml, 60 min after LR, P < 0.001). C4a and C5a decreased after LR, by 25% 24 h after LR and 30% 2 h after LR, respectively (P < 0.01). C5L2 expression decreased at 4 h, rising at 24 h after LR (PMN: 6.3 ± 1 before LR, 3.1 ± 1, 4 h, 8.3 ± 2, 24 h; P < 0.01). The receptor‐related changes accompanied a diminished C5a‐dependent chemotactic response by PMN (42.1 ± 17 before LR vs. 2.1 ± 3 4 h after LR; P < 0.01) and a reduction of activation upon C5a‐R stimulation as measured by l‐selectin shedding and Mac‐1 expression on PMN. Changes in C5L2 expression on monocytes paralleled postoperative impairment of liver function.

Conclusions

These results indicate that complement components are released after clinical LR and subsequently PMN display altered C5a‐dependent functional responses.
Assessment of Frey procedures: Japanese experience
Authors: Egawa Shinichi , Motoi Fuyuhiko , Sakata Naoaki , Kitamura Yo , Nakagawa Kei , Ohtsuka Hideo , Hayashi Hiroki , Morikawa Takanori , Omura Noriyuki , Ottomo Shigeru , Yoshida Hiroshi , Onogawa Toru , Yamamoto Kuniharu , Akada Masanori , Rikiyama Toshiki , Katayose Yu , Matsuno Seiki , Unno Michiaki
Published: September 2009

Background/Purpose

The Frey procedure, the coring out of the pancreatic head and longitudinal pancreaticojejunostomy, is a safe, easy, and reliable method to solve most of the problems associated with chronic pancreatitis. During long‐term follow up, unexpected relapse in the pancreatic tail was encountered. The pattern of failure and the rationale for a new procedure to treat or prevent such relapse were investigated.

Methods

From 1992 to 2008, 71 patients with chronic pancreatitis underwent the Frey procedure at Tohoku University Hospital. The etiology was alcoholic in 92.6% of them, followed in incidence by idiopathic and hereditary chronic pancreatitis. In the primary operation, besides the Frey procedure, combined resection of the pancreatic tail was performed in three patients, and choledochoduodenostomy was performed in one patient. The follow‐up rate was 92.9%, with a median period of 46 months.

Results

The incidence of early postoperative complications was 18.4%, with one reoperation for gastrointestinal bleeding from the splenic artery. Pain control was achieved in all patients and there was no operative mortality. During the long‐term follow up of 62 patients with the Frey procedure, eight patients had relapse of inflammation and required reoperation. Five of these eight patients had a pseudocyst in the pancreatic tail and underwent distal pancreatectomy (DP).

Conclusions

Relapse occurred in alcoholic middle‐aged male patients, and in the patients with hereditary and idiopathic pancreatitis. Frey‐DP and Frey‐spleen‐preserving DP (SPDP) procedures can be performed safely and effectively to treat the relapse and to prevent relapse in the pancreatic tail.
Lymph node navigation for pancreatic and biliary malignancy by NOTES
Authors: Yasuda Kazuhiro , Kitano Seigo
Published: September 2009

Background

Lymph node navigation and accurate staging of liver or peritoneal metastasis leads to better selection of the optimal treatment for patients with pancreatic and biliary malignancy. Less invasive techniques of detecting lymph node metastasis and distant metastasis would be valuable. Natural orifice translumenal endoscopic surgery (NOTES) is a new, evolving concept of minimally invasive surgery that may be useful for the staging of intraabdominal cancers.

Methods

Review of the literature regarding peritoneoscopy and lymph node mapping and biopsy by NOTES.

Results

NOTES peritoneoscopy for accurate diagnosis and staging of intraabdominal cancers is already in clinical use, and two case reports have shown the safety and feasibility of this technique. Previous experimental studies have also shown that lymph node mapping by NOTES is technically feasible with the currently available devices.

Conclusions

With the continued development of the techniques and technology of NOTES, peritoneoscopy and lymph node mapping by NOTES may become an alternative method for preoperative staging for patients with pancreatic and biliary malignancy.
Responses to precipitation treatment for Haloxylon ammodendron growing on contrasting textured soils
Authors: Zou Ting , Li Yan , Xu Hao , Xu Gui‐Qing
Published: September 2009

The responses to precipitation of Haloxylon ammodendron (C.A. Mey.) Bunge (Chenopodiaceae), a small xerophilous tree growing on contrasting textured soils, were evaluated under no, natural, and double precipitation treatments during the entire growing season of 2006. The contrasting textured soils are sandy and heavy textured, and both are the original habitat of H. ammodendron at the south edge of Gubantonggute Desert, Central Asia. Photosynthesis, leaf water potential, transpiration, water use efficiency and leaf biomass production were monitored throughout the growing season. Root distribution of H. ammodendron was evaluated at the end of the experiment. Overall, this small tree did not show significant response to a large summer precipitation pulse or precipitation treatments, in terms of photosynthetic carbon assimilation on either soil. The leaf water potential, transpiration, and water use efficiency appeared to be highly sensitive to a large precipitation pulse and precipitation treatments in sandy soil; and leaf biomass production was also much higher for plants in sandy than that of heavy‐textured soil. In sandy soil, defoliation occurred when pre‐dawn leaf water potential dropped below −3.0 MPa, while in heavy‐textured soil, defoliation occurred when pre‐dawn leaf water potential dropped below −3.75 MPa. For similar above‐ground parts, the small trees at the sandy site developed much deeper root systems and had nearly double the surface area of feeder roots compared to those at the heavy‐textured site. Partially owning to the deeper and larger root system, H. ammodendron growing at coarse‐textured site was in better water conditions than those at heavy‐textured site under the same climatic conditions.
Total Synthesis and Antileishmanial Activity of the Natural Occurring Acetylenic Fatty Acids 6‐Heptadecynoic Acid and 6‐Icosynoic Acid
Authors: Carballeira Néstor M. , Cartagena Michelle M. , Prada Christopher Fernández , Rubio Celia Fernández , Balaña‐Fouce Rafael
Published: September 2009

The first total syntheses of the naturally occurring acetylenic fatty acids—6‐heptadecynoic acid (59% overall yield) and 6‐icosynoic acid (34% overall yield)—was accomplished in four steps. Using the same synthetic sequence the naturally occurring fatty acids (6Z)‐heptadecenoic acid (46% overall yield) and (6Z)‐icosenoic acid (27% overall yield) were also synthesized. The Δ6 acetylenic fatty acids displayed good antiprotozoal activity towards Leishmania donovani promastigotes (EC50 = 1–6 µg/mL), but the 6‐icosynoic acid was the most effective in the series. In addition, the (6Z)‐icosenoic acid was a much better antiprotozoal compound (EC50 = 5–6 µg/mL) than the (6Z)‐heptadecenoic acid (EC50 > 25 µg/mL). The saturated fatty acids n‐heptadecanoic acid and n‐eicosanoic acid were not effective towards L. donovani, indicating that the Δ6 unsaturation in these fatty acids is necessary for leishmanicidal activity. In addition, both the 6‐icosynoic acid and the (6Z)‐icosenoic acid were inhibitors of the Leishmania DNA topoisomerase IB enzyme (EC50's = 36–49 µM), a possible intracellular target for these compounds. This is the first study assessing fatty acids as inhibitors of the Leishmania DNA topoisomerase IB enzyme.
Efficacy of a teat dip containing the bacteriocin lacticin 3147 to eliminate Gram-positive pathogens associated with bovine mastitis
Authors: Klostermann Katja , Crispie Fiona , Flynn Jim , Meaney William J , Paul Ross R , Hill Colin
Published: September 2009

On most dairy farms teat dips are applied to the teats of cows either before or after milking in order to prevent pathogens from gaining access to the mammary gland via the teat canal. In the present experiments, a natural teat dip was developed using a fermentate containing the live bacteriumLactococcus lactisDPC 3251. This bacterium produces lacticin 3147, a two-component lantibiotic which was previously shown to effectively kill Gram-positive mastitis pathogens. Lacticin 3147 activity in the fermentate was retained at 53% of its original level following storage for 3 weeks at 4°C. In the initial experiments in vitro, 105colony-forming units/ml (cfu/ml) of eitherStaphylococcus aureus,Streptococcus dysgalactiaeorStreptococcus uberiswere introduced into the lacticin-containing fermentate. NeitherStaph. aureusnorStr. dysgalactiaecould be detected after 30 min or 15 min, respectively, whileStr. uberiswas reduced approximately 100-fold after 15 min. Following these trials, preliminary experiments were performed in vivo on teats of lactating dairy cows. In these experiments, teats were coated with each of the challenge organisms and then dipped with the lacticin-containing fermented teat dip. Following a dip contact time of 10 min, staphylococci were reduced by 80% when compared with the undipped control teat. Streptococcal challenges were reduced by 97% forStr. dysgalactiaeand by 90% forStr. uberis. These trials showed that the teat dip is able to reduce mastitis pathogens on the teats of lactating cows.
Equilibrium and travelling-wave solutions of plane Couette flow
Authors: GIBSON J. F. , HALCROW J. , CVITANOVIĆ P.
Published: September 2009

We present 10 new equilibrium solutions to plane Couette flow in small periodic cells at low Reynolds numberReand two new travelling-wave solutions. The solutions are continued under changes ofReand spanwise period. We provide a partial classification of the isotropy groups of plane Couette flow and show which kinds of solutions are allowed by each isotropy group. We find two complementary visualizations particularly revealing. Suitably chosen sections of their three-dimensional physical space velocity fields are helpful in developing physical intuition about coherent structures observed in low-Returbulence. Projections of these solutions and their unstable manifolds from their ∞-dimensional state space on to suitably chosen two- or three-dimensional subspaces reveal their interrelations and the role they play in organizing turbulence in wall-bounded shear flows.
Hearing loss in patients with Behçet's disease: an audiological and transient evoked otoacoustic emission study
Authors: Aslan S , Serarslan G , Savas N , Teksoz E , Dagli S
Published: September 2009

Objective:

To investigate hearing loss in patients with Behçet's disease.

Materials and methods:

Twenty-four consecutive cases of Behçet's disease and 24 sex- and age-matched controls were included in this study. Pure tone and high frequency audiometric tests were performed and pure tone average hearing thresholds calculated for both groups. Transient evoked otoacoustic emission testing was also performed.

Results:

Pure tone audiometry showed a sensorineural hearing loss in 15 of the Behçet's disease ears. Hearing thresholds were significantly higher in the study group than in the control group, on both pure tone frequency (except 0.5 kHz) and high frequency audiometry. Significant reductions in transient evoked otoacoustic emission amplitude were found at 1.4 and 2 kHz in the Behçet's disease patients. There were no significant differences in reproducibility, stimulus intensity or stability, comparing the Behçet's disease patients and controls.

Conclusion:

Significantly lower mid-frequency amplitudes were found in Behçet's patients on transient evoked otoacoustic emission testing.
The Kiwi hoop for Boyle–Davies gag suspension during tonsillectomy
Authors: Ahsan F , Stevenson S
Published: September 2009

We describe an alternative method of suspending the Boyle–Davis gag during tonsillectomy. Use of the traditional Draffin's bipod for positioning patients during tonsillectomy is associated with a number of difficulties. These include limited height adjustment and problems with slipping during operation. We describe an alternative arrangement for suspension of the Boyle-Davis gag. This arrangement has been successfully used for many years, and offers advantages because of its stability and adjustability.
Internal carotid artery dissection following canalith repositioning procedure
Authors: Bergin M , Bird P , Wright A
Published: September 2009

Objective:

To highlight the possibility of internal carotid artery dissection following canalith repositioning procedures.

Case report:

A 52-year-old woman with right posterior canal benign paroxysmal positional vertigo sustained a right carotid artery dissection following a canalith repositioning procedure. The patient also had profound mixed hearing loss associated with otosclerosis, so underwent simultaneous cochlear implantation and occlusion of her posterior semicircular canal, following completion of anticoagulation therapy for her dissection.

Conclusion:

While internal carotid artery trauma is a rare adverse outcome following canalith repositioning procedures, clinicians should be aware of this possibility if patients report unusual symptoms following such procedures.
Multiple long-distance scrambling: Syntax as reflections of processing
Authors: KEMPSON RUTH , KIAER JIEUN
Published: September 2009

This paper argues that, with syntax defined as progressive projection of semantic representations along the left-to-right dimension provided by the sequence of words (Cann, Kempson & Marten 2005), explanations for local and (multiple) nonlocal scrambling of NPs in Japanese and Korean follow from general principles of tree growth, allowing differences between the languages while nevertheless retaining an integrated account of scrambling itself. This formalism is similar to the parsing mechanism of Miyamoto (2002), but goes further in using this as the base grammar formalism, with all concepts of movement replaced by progressive articulation of structural underspecification and tree growth starting from the left periphery. The account extends the analysis of Japanese scrambling of Cann et al. to encompass multiple long-distance scrambling, capturing both the attendant relative locality restriction on the constituents moved, and interaction of this restriction with scope-construal effects. Scope-construal variability is expressible as interaction between individual lexical specifications for the two languages and general constraints on scope construal; and the relative locality constraint on the construal of the expressions involved in multiple long-distance scrambling is an immediate consequence of the general dynamics of the framework. The resulting account extends Hawkins' (2004) program of defining grammars relative to performance considerations.
Externalizing disorders: Cluster 5 of the proposed meta-structure for DSM-V and ICD-11
Authors: Krueger R. F. , South S. C.
Published: October 2009

Background

The extant major psychiatric classifications DSM-IV and ICD-10 are purportedly atheoretical and largely descriptive. Although this achieves good reliability, the validity of a medical diagnosis is greatly enhanced by an understanding of the etiology. In an attempt to group mental disorders on the basis of etiology, five clusters have been proposed. We consider the validity of the fifth cluster, externalizing disorders, within this proposal.

Method

We reviewed the literature in relation to 11 validating criteria proposed by the Study Group of the DSM-V Task Force, in terms of the extent to which these criteria support the idea of a coherent externalizing spectrum of disorders.

Results

This cluster distinguishes itself by the central role of disinhibitory personality in mental disorders spread throughout sections of the current classifications, including substance dependence, antisocial personality disorder and conduct disorder. Shared biomarkers, co-morbidity and course offer additional evidence for a valid cluster of externalizing disorders.

Conclusion

Externalizing disorders meet many of the salient criteria proposed by the Study Group of the DSM-V Task Force to suggest a classification cluster.
Bullying victimization in youths and mental health problems: ‘Much ado about nothing’?
Authors: Arseneault L. , Bowes L. , Shakoor S.
Published: September 2009

Bullying victimization is a topic of concern for youths, parents, school staff and mental health practitioners. Children and adolescents who are victimized by bullies show signs of distress and adjustment problems. However, it is not clear whether bullying is the source of these difficulties. This paper reviews empirical evidence to determine whether bullying victimization is a significant risk factor for psychopathology and should be the target of intervention and prevention strategies. Research indicates that being the victim of bullying (1) is not a random event and can be predicted by individual characteristics and family factors; (2) can be stable across ages; (3) is associated with severe symptoms of mental health problems, including self-harm, violent behaviour and psychotic symptoms; (4) has long-lasting effects that can persist until late adolescence; and (5) contributes independently to children's mental health problems. This body of evidence suggests that efforts aimed at reducing bullying victimization in childhood and adolescence should be strongly supported. In addition, research on explanatory mechanisms involved in the development of mental health problems in bullied youths is needed.
Thinking with Animals in Upper Palaeolithic Rock Art
Authors: Sauvet Georges , Layton Robert , Lenssen-Erz Tilman , Taçon Paul , Wlodarczyk André
Published: October 2009

This article develops a novel method for assessing the cultural context of rock art, and applies it to the rock art of the Upper Palaeolithic of France and Spain. The article relies on a generative approach, assuming that artists have the potential to choose which motifs to select from the repertoire or vocabulary of their artistic system, but that appropriate choices at any place are guided by the location of that site within the culturally-mediated geography of the region. Ethnographic studies of rock art depicting animal species produced in the contexts of totemism, shamanism and everyday life are used as reference points in an analytical framework, which is then applied to a number of ancient traditions.
‘Work and Don't Lose Hope’: Republican Forced Labour Camps during the Spanish Civil War
Authors: RUIZ JULIUS
Published: September 2009

This article examines the use of forced labour in Republican Spain during the civil war. Although much has recently been written on Francoist camps, very little research has been undertaken on their Republican counterparts. As a consequence the significance of Republican camps has not been recognised. Although some historians argue that the Republicans used forced labour only in a desperate attempt to avoid military defeat, this article demonstrates that labour camps were an integral aspect of Republican ‘popular justice’. Work, it was argued, would redeem ‘fascists’ by allowing them to contribute to the economic reconstruction and transformation of Spain.
Liberal Internationalism 3.0: America and the Dilemmas of Liberal World Order
Authors: Ikenberry G. John
Published: September 2009

Liberal international order—both its ideas and real-world political formations—is not embodied in a fixed set of principles or practices. Open markets, international institutions, cooperative security, democratic community, progressive change, collective problem solving, the rule of law—these are aspects of the liberal vision that have made appearances in various combinations and changing ways over the last century. I argue that it is possible to identify three versions or models of liberal international order—versions 1.0, 2.0, and 3.0. The first is associated with the ideas of Woodrow Wilson, the second is the Cold War liberal internationalism of the post-1945 decades, and the third version is a sort of post-hegemonic liberal internationalism that has only partially appeared and whose full shape and logic is still uncertain. I develop a set of dimensions that allow for identifying different logics of liberal international order and identify variables that will shape the movement from liberal internationalism 2.0 to 3.0.
Integration of NG2-glia (synantocytes) into the neuroglial network
Authors: Wigley Rebekah , Butt Arthur M.
Published: September 2009

NG2-glia are a distinct class of CNS glial cells that are generally classed as oligodendrocyte progenitor cells. However, in the adult CNS a large fraction of NG2 cells does not appear to divide or generate oligodendrocytes. The functions of these adult NG2-glia, which we have termed synantocytes, are unknown. NG2-glia (synantocytes) form interactive domains with astrocytes and neurons. Within their domains, NG2-glia and astrocytes contact the same neurons, form multiple heterologous contacts with each other, and contact pericytes which regulate cerebral blood flow. NG2-glia receive presynaptic input from neurons and respond to neurotransmitters released at synapses. In addition, NG2-glia are intimately associated with astroglia and respond to astroglial signals, a hitherto neglected aspect of NG2-glial cell physiology. The non-overlapping domain organisation of astrocytes is believed to be important in isolating and integrating activity at the synapses and blood vessels within their domains. The domains of NG2-glia overlap with astrocytes, suggesting they could play a role in integrating non-overlapping astrocyte domains.
Is activity regulation of late myelination a plastic mechanism in the human nervous system?
Authors: Ullén Fredrik
Published: September 2009

Studies on various animal models have established that neuronal activity can influence the myelination process. Are such mechanisms present in humans, and do they mediate experience-driven white matter plasticity not only during early development but also in adolescents and adults? While there is as yet no direct evidence for this, a number of findings – reviewed here – are consistent with this idea. First, postmortem and neuroimaging studies show that the human white matter development is a protracted process that continues well into adulthood. Second, developmental changes and individual differences in white matter structure are related to differences in neural activity and behavior. Finally, studies on effects of long-term training, in particular in musicians, show strong relations between training and white matter structure. I conclude by briefly discussing possible types of white matter plasticity that could underlie these findings, emphasizing a distinction between indirect myelination plasticity, where the myelin sheath grows in parallel with the axon itself, and direct myelination plasticity, where the myelin sheath thickness is modulated independently of axonal diameter.
Selbstkontrollanforderunge nals spezifische Belastungsquelle bei der Arbeit
Authors: Schmidt Klaus-Helmut , Neubach Barbara
Published: September 2009

Zusammenfassung. In Anlehnung an neuere theoretische Entwicklungen und empirische Befunde aus der sozial- und kognitionspsychologischen Grundlagenforschung ging die vorliegende Studie der Frage nach, ob Selbstkontrollanforderungen bei der Arbeit bedeutsame Einflüsse auf Indikatoren der Arbeitsbeanspruchung ausüben. Zur Beantwortung dieser Frage wurden drei Formen von Selbstkontrollanforderungen bei der Arbeit (Impulskontrolle, Ablenkungen widerstehen, Überwinden innerer Widerstände) in Kombination mit traditionellen Belastungsformen und Ressourcen in ihren Beanspruchungswirkungen untersucht. Die bei 518 Beschäftigten einer großen Landesverwaltung erhobenen Daten belegen, dass die berücksichtigten Selbstkontrollanforderungen signifikante zusätzliche Varianzanteile in verschiedenen Indikatoren der psychischen Beanspruchung aufklären. Von den Selbstkontrollanforderungen gehen zudem einige eigenständige Einflüsse auf die Beanspruchung aus. Muskuloskelettale Beschwerden spiegeln als Indikator physischer Beanspruchung dagegen keine vergleichbar starken Einflüsse der Selbstkontrollanforderungen wider.
Was wollen jüngere und ältere Erwerbstätige erreichen?
Authors: Zacher Hannes , Degner Manuela , Seevaldt Robert , Frese Michael , Lüdde Jörg
Published: September 2009

Zusammenfassung. Angesichts des demografischen Wandels wird es für Unternehmen immer wichtiger, jüngere Mitarbeiter zu binden und ältere Mitarbeiter durch Arbeitsgestaltung zu motivieren. Bei der Bewältigung dieser Herausforderungen sollten altersbezogene Unterschiede in beruflichen Zielen berücksichtigt werden. In dieser Studie untersuchen wir die Inhalte und Merkmale beruflicher Ziele von Erwerbstätigen unterschiedlichen Alters. Wir befragten 150 Erwerbstätige aus verschiedenen Dienstleistungsberufen (mittleres Alter = 44 Jahre, Altersspanne 19 bis 60 Jahre) zu ihren wichtigsten beruflichen Zielen. Erwerbstätige, die Ziele im Bereich betriebliches Engagement nannten, waren signifikant älter als Personen mit anderen Zielen. Erwerbstätige, d ie Ziele in den Bereichen Weiterbildung und Bezahlung/Karriere nannten, waren signifikant jünger als Personen mit anderen Zielen. Nachdem für Geschlecht, Bildung und Arbeitsmerkmale kontrolliert wurde, zeigten sich keine altersbezogenen Unterschiede in den Bereichen Zusammenarbeit, Beschäftigungssicherheit, Arbeitszeit, Wohlbefinden und neue Herausforderungen. Außerdem bestanden keine Zusammenhänge zwischen Alter und den Zielmerkmalen Spezifität, Planungsintensität sowie positive und negative Zielemotionen. Wir empfehlen Unternehmen, älteren Mitarbeitern mehr betriebliches Engagement zu ermöglichen und jüngere Mitarbeiter durch Entwicklungsmöglichkeiten und angemessene Bezahlung zu binden.
Observations of He+ concentrations in the topside ionosphere under equinox conditions near solar maximum: Morningside morphology
Authors: West K. H.
Published: September 2009

Average He+ concentrations are examined for solar maximum conditions at equinox using data from Defense Meteorological Satellite Program (DMSP) flights F13 and F15. The DMSP spacecraft have Sun‐synchronous orbits at 800 km altitude. F13 data were taken under presunrise conditions, while F15 data were taken at midmorning local times. Data are averaged for 31 days centered on the northern spring and fall equinoxes between ±40° magnetic latitude. Both the He+ concentration and He+ fraction show significant longitudinal and latitudinal variation, which can be accounted for by neutral wind induced ion drag. The He+ fraction can reach as much as 40% of the total plasma density in the presunrise hours, but 10% or less of the total plasma density at midmorning. While the He+ concentrations before sunrise and at midmorning have comparable magnitudes, the midmorning values of the He+ fraction are much more uniform than in the presunrise data. Examination of the F10.7 cm solar flux and geomagnetic activity implies solar flux has a much greater influence on He+ concentrations. The level of solar flux as well as the amount of variability in the solar flux appear to influence the average He+ concentrations and fractions.
Simulation of the Argo observing system in an ocean general circulation model
Authors: Kamenkovich Igor , Cheng Wei , Sarachik E. S. , Harrison D. E.
Published: September 2009

The main goal of this study is to determine how well large‐scale temperature, salinity, upper ocean heat content (UOHC), and surface mixed layer fields and their variability can be reconstructed from the Argo observing system. The approach is to sample and reconstruct these oceanic fields from a coarse‐resolution ocean general circulation model (OGCM), quantify the errors in the reconstructed fields, and analyze the factors controlling these errors. In particular, this study analyzes the effects of float movements on the spatial coverage and reconstruction of temporal variability. Overall performance of the simulated Argo array is good, and the reconstructed climatological means of such key quantities as the temperature, salinity, UOHC, and mixed layer depth are very close to the actual OGCM‐simulated values in most of the global ocean. However, the differences between the reconstructed and actual fields (“reconstruction errors”) are more significant in several regions with strong currents, such as the Antarctic Circumpolar Current (ACC). The results also suggest that the detection of the year‐to‐year changes in UOHC in the ACC, in high‐latitude North Atlantic, and near the coasts can be particularly problematic. As illustrated by sensitivity experiments, the main effect of float movements is to increase reconstruction errors. This adverse effect of float movements is the main cause of large errors in the UOHC interannual difference in the ACC. When the spatial sampling coverage is improved, for example, by increasing the number of floats, the accuracy of reconstruction improves substantially.
Mixing state of nonvolatile aerosol particle fractions and comparison with light absorption in the polluted Beijing region
Authors: Wehner B. , Berghof M. , Cheng Y. F. , Achtert P. , Birmili W. , Nowak A. , Wiedensohler A. , Garland R. M. , Pöschl U. , Hu M. , Zhu T.
Published: September 2009

In Chinese megacities the problems of air pollution are frequently obvious as hazy layers covering large areas combined with low visibility. To estimate the aerosol effect on regional and global climate, the knowledge of light‐absorbing and light‐scattering compounds as well as their mixing state is essential. A Volatility Tandem DMA (VTDMA) was used to measure nonvolatile fractions (at 300°C) of submicrometer aerosol particles. The remaining size distributions were divided into three fractions, corresponding to particles with a low‐volatile, medium‐volatile, and high‐volatile fraction. The particles with a low‐volatile fraction are equivalent with externally mixed nonvolatile (refractory) material; in the observed size range, this fraction is assumed to consist mainly of soot. Combined with number size distributions, the number and volume concentrations of externally and internally mixed nonvolatile particles were calculated. In a parallel study by Cheng et al. (2009) the results were used in a Mie model and compared with measured absorption coefficients showing a good agreement. During Campaigns of Air Quality Research in Beijing and Surrounding Region 2006 (CAREBeijing‐2006), large variations in the mixing state were found, especially between new particle formation and heavily polluted days. The fraction of externally mixed soot decreased from ∼37% during clean to 18% during heavily polluted periods, parallel to an increase in particle mass concentration mainly caused by the production of secondary aerosol material. In the nucleation mode, high particle number fractions with high‐volatile fractions were found (∼64% in contrast to ∼24% on a nonevent day); that is, refractory material is produced during nucleation and growth.
Importance of wind conditions, fetch, and water levels on wave‐generated shear stresses in shallow intertidal basins
Authors: Fagherazzi S. , Wiberg P. L.
Published: September 2009

Wave‐generated shear stresses are the main mechanism responsible for sediment erosion on tidal flats and regulate both sediment concentrations in the water column and, together with tidal currents, sediment export to salt marshes and to the ocean. We present herein a simple method to estimate sediment erosion potential in shallow tidal basins caused by wind wave events. The method determines the aggregate response of the entire basin, combining in a simple framework the contribution from different landscape units. The method is applied to a system of shallow tidal basins along the Eastern Shore of Virginia, USA. Our analysis unravels the interplay of basin morphology, tidal elevation, and wind direction on water depth, fetch, and the resulting wave‐generated shear stresses. We identify four bottom shear stress regimes as a function of water elevation produced by wind waves in shallow micromesotidal systems. For water elevations below mean lower low water (MLLW), an increase in fetch is counteracted by an increase in depth, so that the average bottom shear stress and erosion potential is maintained constant. For elevations between MLLW and mean sea level (MSL), the increase in water depth dominates the increase in wave height, thus reducing the bottom shear stresses. For elevations between MSL and mean higher high water (MHHW), the range associated with stable salt marsh platforms, flooding of salt marshes increases fetch, wave height, and bottom shear stresses, producing the largest resuspension events in the bay. For elevations above MHHW, the increase in depth once again dominates increases in wave height, thereby reducing average bottom shear stresses and potential erosion.
Grain size dependency in sandbank modeling for the case of uniform sediment
Authors: Idier D. , van der Veen H. H. , Hulscher S. J. M. H.
Published: September 2009

A 2‐D depth‐integrated stability analysis designed for marine tidal sandbanks is developed to investigate the relative influence of the grain size–dependent parameters on the simulated dynamics of the sandbanks for the case of uniform sediment. The model is applied to a real case in the North Sea. Assuming that the model is valid mainly in an area where bed load is the dominant sediment transport mode, the model taking into account the grain size dependencies gives a better prediction of sandbank occurrence than models neglecting these dependencies. All the grain size–dependent parameters are investigated separately. Focusing on the morphological time and wavelength of the sandbanks, this paper demonstrates that neglecting the grain size dependencies, especially the transport threshold, has a drastic influence on the dynamics of modeled sandbanks, especially on the sandbanks growth rate. The influence on the geometrical properties (wavelength and orientation) is less pronounced.
Metamorphism of stratified firn at Dome Fuji, Antarctica: A mechanism for local insolation modulation of gas transport conditions during bubble close off
Authors: Fujita Shuji , Okuyama Junichi , Hori Akira , Hondoh Takeo
Published: September 2009

The evolution of the structure of a 112.59 m long firn core recovered at Dome Fuji, East Antarctica, was investigated in order to improve understanding of firn densification and bubble formation processes, which are important for interpreting local insolation proxies used for astronomical dating of deep ice cores. Using selected samples, we measured physical properties including (1) the relative dielectric permittivities in both the vertical and horizontal planes, (2) the bulk density at a resolution of millimeters, (3) the three‐dimensional geometric structure of pore space, and (4) crystal orientation fabrics. We found that the firn at Dome Fuji contains horizontal strata with thicknesses of several centimeters. Near the surface of the ice sheet, these strata are characterized by contrasting bulk density. Earlier field studies suggest that summer insolation causes densification of surface firn. Down to ∼30 m, density maxima exhibited a clear positive correlation with the strength of structural anisotropy and c axis clustering around the vertical. In contrast, the correlation is negative in deeper firn, confirming previous findings that initially less dense firn became denser than initially dense firn. In addition, numerous examples of textures indicating that deformation preferentially occurred in weaker layers were found. Moreover, the initially dense firn layers were more permeable for air near the bottom of firn. We propose a model linking firn properties with conditions for the gas transport processes near the bottom of firn. The model explains how stronger insolation can lead to bulk ice with a lower O2/N2 ratio and smaller total gas content.
Ionospheric dynamics and drivers obtained from a physics‐based data assimilation model
Authors: Scherliess Ludger , Thompson Donald C. , Schunk Robert W.
Published: September 2009

The ionosphere‐plasmasphere system at low and middle latitudes is strongly coupled, and therefore, a study of ionospheric dynamics must take into account the interaction between the two domains. As shown by meteorologists and oceanographers, a powerful way of modeling dynamic systems is with the use of data assimilation models. At Utah State University, we have developed two data assimilation models with different complexity, and both provide global and regional specifications of the three‐dimensional (3‐D) ionosphere‐plasmasphere densities. One of these models is a Full Physics‐Based Kalman filter data assimilation model, which is based on a physics‐based model for the ionosphere‐plasmasphere system, a diverse array of data sources, and an ensemble Kalman filter data assimilation technique. This model covers the ionosphere‐plasmasphere system from 90 to 30,000 km altitude and includes six ion species (NO+, N2+, O2+, O+, He+, H+). The strength of this model is that in addition to the global and regional 3‐D ionosphere electron density distribution it also self‐consistently determines the corresponding ionospheric drivers, including the thermospheric neutral winds and the low‐latitude electric fields. The model can assimilate a variety of different data types, including GPS/total electron content from hundreds of ground‐based receivers, in situ Ne from several DMSP satellites, bottomside Ne profiles from tens of ionosondes, and occultation data from the six COSMIC satellites. In this study, the model was used to specify the low‐latitude and midlatitude ionosphere together with the ionospheric driving forces and their temporal and spatial variability.
A 750 year ice core record of past biogenic emissions from Siberian boreal forests
Authors: Eichler Anja , Brütsch Sabina , Olivier Susanne , Papina Tatyana , Schwikowski Margit
Published: September 2009

Emissions from forests represent an important source of gaseous precursors of aerosols that can significantly alter the regional radiation balance. Long‐term records of biogenic emissions are available for Northern America and the Amazon Basin, whereas the historical development of emissions from Siberian forests, comprising about 20% of the world's forested area, is unknown so far. Here we investigate ice core ammonium and formate records for the last 750 years, representing biogenic emissions from boreal Siberian forests in the pre‐industrial era. Biogenic emissions were found to be closely related to changes in temperature following variations in solar activity. In addition, anthropogenic emissions have caused a strong increase of the ammonium concentrations and a drop of the formate concentrations in the last 60 years.
Benefits, risks, and costs of stratospheric geoengineering
Authors: Robock Alan , Marquardt Allison , Kravitz Ben , Stenchikov Georgiy
Published: October 2009

Injecting sulfate aerosol precursors into the stratosphere has been suggested as a means of geoengineering to cool the planet and reduce global warming. The decision to implement such a scheme would require a comparison of its benefits, dangers, and costs to those of other responses to global warming, including doing nothing. Here we evaluate those factors for stratospheric geoengineering with sulfate aerosols. Using existing U.S. military fighter and tanker planes, the annual costs of injecting aerosol precursors into the lower stratosphere would be several billion dollars. Using artillery or balloons to loft the gas would be much more expensive. We do not have enough information to evaluate more exotic techniques, such as pumping the gas up through a hose attached to a tower or balloon system. Anthropogenic stratospheric aerosol injection would cool the planet, stop the melting of sea ice and land‐based glaciers, slow sea level rise, and increase the terrestrial carbon sink, but produce regional drought, ozone depletion, less sunlight for solar power, and make skies less blue. Furthermore it would hamper Earth‐based optical astronomy, do nothing to stop ocean acidification, and present many ethical and moral issues. Further work is needed to quantify many of these factors to allow informed decision‐making.
A multiparameter approach to volcano monitoring based on 4D analyses of seismo‐volcanic and acoustic signals: The 2008 Mt. Etna eruption
Authors: Di Grazia G. , Cannata A. , Montalto P. , Patanè D. , Privitera E. , Zuccarello L. , Boschi E.
Published: September 2009

Volcanic tremor and low frequency events, together with infrasound signals, can represent important precursory phenomena of eruptive activity because of their strict relationship with eruptive mechanisms and with fluid flows through the volcano's feeding system. Important variations of these seismo‐volcanic and infrasound signals, recorded at Mt. Etna volcano, occurred both in the medium‐ and short‐term before the eruption, that took place on 13 May 2008. The most significant changes were observed in the frequency content and location of LP events, as well as in volcanic tremor location, that allowed us to track the magma pathway feeding the 2008 eruptive activity. The infrasound showed three different families of events linked to the activity of the three active vents: North‐East Crater, South‐East crater and the eruptive fissure. The seismic and infrasonic variations reported, corroborated by ground deformations variations, help to develop a quantitative prediction and early‐warning system for effusive and/or explosive eruptions.
The 2009 L'Aquila (central Italy) MW6.3 earthquake: Main shock and aftershocks
Authors: Chiarabba C. , Amato A. , Anselmi M. , Baccheschi P. , Bianchi I. , Cattaneo M. , Cecere G. , Chiaraluce L. , Ciaccio M. G. , De Gori P. , De Luca G. , Di Bona M. , Di Stefano R. , Faenza L. , Govoni A. , Improta L. , Lucente F. P. , Marchetti A. , Margheriti L. , Mele F. , Michelini A. , Monachesi G. , Moretti M. , Pastori M. , Piana Agostinetti N. , Piccinini D. , Roselli P. , Seccia D. , Valoroso L.
Published: September 2009

A MW 6.3 earthquake struck on April 6, 2009 the Abruzzi region (central Italy) producing vast damage in the L'Aquila town and surroundings. In this paper we present the location and geometry of the fault system as obtained by the analysis of main shock and aftershocks recorded by permanent and temporary networks. The distribution of aftershocks, 712 selected events with ML ≥ 2.3 and 20 with ML ≥ 4.0, defines a complex, 40 km long, NW trending extensional structure. The main shock fault segment extends for 15–18 km and dips at 45° to the SW, between 10 and 2 km depth. The extent of aftershocks coincides with the surface trace of the Paganica fault, a poorly known normal fault that, after the event, has been quoted to accommodate the extension of the area. We observe a migration of seismicity to the north on an echelon fault that can rupture in future large earthquakes.
Estimating mixing rates from seismic images of oceanic structure
Authors: Sheen K. L. , White N. J. , Hobbs R. W.
Published: September 2009

An improved understanding of the spatial distribution of diapycnal mixing in the oceans is the key to elucidating how meridional overturning circulation is closed. The challenge is to develop techniques which can be used to determine the variation of diapycnal mixing as a function of space and time throughout the oceanic volume. One promising approach exploits seismic reflection imaging of thermohaline structure. We have applied spectral analysis techniques to fine‐structure undulations observed on a seismic transect close to the Subantarctic Front in the South Atlantic Ocean. 91 horizontal spectra were fitted using a linear combination of a Garrett‐Munk tow spectrum for internal waves and a Batchelor model for turbulence. The fit between theory and observation is excellent and enables us to deduce the spatial variability and context of diapycnal mixing rates, which range from 10−5 to 10−3.5m2s−1.