bluuebunny/crossref_metadata_2025 huggingface dataset:
Jupiter – friend or foe? I: The asteroids
Authors: Horner J. , Jones B.W.
Published: July 2008

The asteroids are a major source of potential impactors on the Earth today. It has long been assumed that the giant planet Jupiter acts as a shield, significantly lowering the impact rate on the Earth from both cometary and asteroidal bodies. Such shielding, it is claimed, enabled the development and evolution of life in a collisional environment, which is not overly hostile. The reduced frequency of impacts, and of related mass extinctions, would have allowed life the time to thrive, where it would otherwise have been suppressed. However, in the past, little work has been carried out to examine the validity of this idea. In the first of several papers, we examine the degree to which the impact risk resulting from a population representative of the asteroids is enhanced or reduced by the presence of a giant planet, in an attempt to understand fully the impact regime under which life on Earth developed. Our results show that the situation is far less clear cut that has previously been assumed, that is, the presence of a giant planet can act toenhancethe impact rate of asteroids on the Earth significantly.
Intoxikation mit einem unbekannten Sedativum
Authors: Bodmer M. , Bodmer M. , Liechti M.E. , Christ A.
Published: July 2008

Wir beschreiben einen 64-jährigen Patienten, der in komatösem Zustand auf die medizinische Notfallstation zugewiesen wird. Bei Vorliegen eines sedativen Toxidroms wird die Verdachtsdiagnose einer Intoxikation mit unbekanntem Sedativum gestellt. Im Blut wird Phenobarbital nachgewiesen. Die Dekontaminationsmassnahmen und die Therapie einer Intoxikation mit Phenobarbital werden diskutiert.
Nierenkolik bei einem jungen Mann
Authors: Zobrist M. , Kneubühl, A. , Pfammatter Th. , Pfiffner R. , Keusch G.
Published: July 2008

Eine Nierenkolik bei einem jungen Mann entpuppte sich als Niereninfarkt am Unterpol der linken Niere infolge Dissektion einer akzessorischen linken Nierenarterie bei fibromuskulärer Dysplasie. In der Folge entwickelte sich eine arterielle Hypertonie. Eine transarterielle Ethanolablation und ein Coiling der akzessorischen linken Nierenarterie führte zu einer erfolgreichen Therapie der arteriellen Hypertonie.
Gesundheitsrisiken bei Unternehmern
Authors: Rau Renate , Hoffmann Katja , Metz Ulrike , Richter Peter Georg , Rösler Ulrike , Stephan Ute
Published: July 2008

An einer Studie zum Zusammenhang zwischen der Gesundheit von Unternehmern, deren Arbeitsmerkmalen und deren Erfolg nahmen 53 klein- und mittelständische Unternehmer teil. Erfasste Arbeitsmerkmale waren: Handlungs-/Entscheidungsspielraum, Arbeitsintensität, Arbeitszeit, Konkurrenzdruck und Prognose über die Auftragsentwicklung. Der Unternehmenserfolg wurde über das Mitarbeiterwachstum, die Möglichkeit des Unternehmers, von seiner Firma abwesend zu sein (Urlaubstage), und dem erlebten Unternehmenserfolg operationalisiert. Gesundheitsindikatoren waren Depression, Angst, vitale Erschöpfung, Schlafstörungen und Bluthochdruck. Im Vergleich zur Gesamtbevölkerung wiesen die Unternehmer in allen untersuchten Gesundheitsvariablen häufiger Beeinträchtigungen auf. Regressionsanalysen ergaben, dass lange Arbeitszeiten und Konkurrenzdruck mit einer verzögerten Rückstellung des systolischen Blutdrucks (SBD) in der Freizeit und Nacht einhergingen. Alle untersuchten Erfolgsmerkmale waren für die Gesundheit prädiktiv. So war Mitarbeiterwachstum negativ mit dem SBD während der Arbeit sowie Schlafstörungen assoziiert. Je mehr Unternehmenserfolg erlebt wurde, desto geringer waren die Werte für vitale Erschöpfung und Depression. Die Urlaubsdauer war negativ mit Angst und vitaler Erschöpfung korreliert. Insgesamt hatte von den Arbeitsmerkmalen nur die Dauer der Arbeitszeit einen Effekt auf die Gesundheit von Unternehmern. Daneben existieren aber offensichtlich weitere Faktoren, die mit der Unternehmergesundheit in Beziehung stehen. Dies sind neben dem Konkurrenzdruck am Markt insbesondere Indikatoren des Unternehmenserfolgs.
Commitment und Identifikation in Organisationen
Authors: Franke Franziska , Felfe Jörg
Published: July 2008

Die arbeits- und organisationspsychologische Bindungsforschung beschäftigt sich aktuell mit der Integration der Konzepte Commitment und Identifikation. Fragen, die es dabei empirisch zu klären gilt, sind a) wie unterschiedlich die Multifacettenmodelle beider Konzepte tatsächlich sind und b) inwieweit sich Unterschiede in der Vorhersage von Outcomes zeigen. In einer Stichprobe mit 349 Personen werden die Bindung an die Organisation, das Team und die eigene Karriere parallel mit Commitment- und Identifikationsmaßen erhoben. In einer Multitrait-Multimethod-Analyse zeigen beide Instrumente konvergente Validität. Auch lässt sich in konfirmatorischen Faktorenanalysen die Differenzierbarkeit von Commitment und Identifikation nachweisen. Daraus resultierend zeigen Regressionsanalysen moderate unabhängige Varianzerklärungen von Commitment und Identifikation bei der Vorhersage von Arbeitszufriedenheit und Kündigungsabsichten. Bei der Vorhersage von Organizational Citizenship Behavior leistet Identifikation keinen bzw. nur einen geringen zusätzlichen Beitrag.
Ist die Wirkung fragenbasierten reflexiven Auseinandersetzens mit Entwurfslösungen aufgabenabhängig?
Authors: Winkelmann Constance , Melzer Marlen , Hacker Winfried
Published: July 2008

In dieser experimentellen Studie (N = 153) wird untersucht, ob und in welchem Maße der lösungsverbessernde Effekt einer fragenbasierten reflexiven Auseinandersetzung mit der eigenen Lösung auch für eine konstruktive Entwurfsaufgabe nachgewiesen werden kann, die sich bei vergleichbarer Schwierigkeit inhaltlich von dem bisher untersuchten Mechanikproblem unterscheidet. Damit soll für die Wirksamkeit der eingesetzten Frage-Antwort-Technik ein aufgabenspezifischer bzw. Inhaltseffekt ( Wason, 1966 ) ausgeschlossen werden. Die Ergebnisse zeigen signifikante Lösungsgüteverbesserungen nach Einsatz der Fragetechnik in gleichem Umfang auch bei der inhaltlich andersartigen Entwurfsaufgabe, wodurch die Übertragbarkeit dieser Unterstützungsmöglichkeit des Design Problem Solving nachgewiesen werden konnte.
Entwicklung des Schlafverhaltens im Säuglingsalter
Authors: Heitkamp Andreas , Pauli-Pott Ursula
Published: July 2008

In der vorliegenden Arbeit werden Beziehungen zwischen dem Geburtsgewicht, der kindlichen Gewichtsentwicklung, der positiven und negativen Reaktivität des Kindes und der mütterlichen Depressionsneigung/Ängstlichkeit mit der Entwicklung von Schlafverhaltensmerkmalen am Ende des ersten Lebensjahres untersucht. An der Längsschnittstudie nahmen insgesamt 101 Bezugspersonen-Kind-Paare teil. Alle Kinder waren gesunde Erstgeborene mit einem Geburtsgewicht über 2500 g. Untersuchungen fanden im Alter der Kinder von vier, acht und 12 Monaten statt. Zur Erfassung des kindlichen Schlafverhaltens, der Reaktivität des Kindes und der Depressivität/Ängstlichkeit der Bezugsperson wurden strukturierte Interviews mit der Bezugsperson, Fragebogen und standardisierte Verhaltensbeobachtungen eingesetzt. Die Daten zur Gewichtsentwicklung wurden den Vorsorgeuntersuchungsheften entnommen. Es konnte gezeigt werden, dass Kinder, die im Alter von 12 Monaten nachts häufig aufwachten, ein relativ geringes Körpergewicht, Phasen exzessiven Schreiens noch im Alter von vier Monaten, eine geringe positive und hohe negative Reaktivität zeigten. Die Mütter dieser Kinder beschrieben sich als depressiv und ängstlich.
Elternbezogene Förderung der phonologischen Bewusstheit im Kindergartenalter
Authors: Koglin Ute , Fröhlich Linda P. , Metz Dorothee , Petermann Franz
Published: July 2008

Im vorliegenden Beitrag wird ein Elternprogramm zur Förderung der phonologischen Bewusstheit für Kinder im Vorschulalter, „Lobo vom Globo“, vorgestellt. Das Training richtet sich gezielt an Eltern und erstreckt sich über einen Zeitraum von fünf Wochen. Die Bedeutung der phonologischen Bewusstheit und ihrer vorschulischen Förderung für das Erlernen des Lesens und Rechtschreibens ist inzwischen umfangreich dokumentiert. Es wird untersucht, ob und inwiefern Vorschulkinder von dem Training zur phonologischen Bewusstheit „Lobo vom Globo“ profitieren. Es wurde ein Elterntraining zur Förderung der phonologischen Bewusstheit eingesetzt. Berichtet werden die Ergebnisse von insgesamt 70 Kindern im letzten bzw. vorletzten Kindergartenjahr, bei denen unmittelbar vor und nach dem Training die phonologischen Fertigkeiten erfasst wurden (Interventionsgruppe: n = 35). Signifikante Effekte zeigen sich vor allem im Bereich der phonologischen Bewusstheit im weiteren Sinne. Besonders deutliche Effekte konnten für die älteren Kinder (5 Jahre und älter) verzeichnet werden.
Irrationale Kognitionen als Korrelate emotionaler Kompetenzen aus dem Kontext emotionaler Intelligenz und individueller Zufriedenheit am Arbeitsplatz
Authors: Spörrle Matthias , Welpe Isabell M. , Ringenberg Iris , Försterling (†) Friedrich
Published: July 2008

Zusammenfassung Der Zusammenhang zwischen irrationalen Kognitionen, emotionalen Kompetenzen aus dem Kontext emotionaler Intelligenz sowie Lebens- und Arbeitszufriedenheit wird aus Perspektive der Rational-Emotiven Verhaltenstherapie (REVT; Ellis, 1962 , 1994 ) untersucht. Diese postuliert, dass rationale besser als irrationale Kognitionen zur Bewältigung emotionsrelevanter Situationen sowie zur Emotionskontrolle geeignet sind und somit als eine Determinante emotionaler Intelligenz und Zufriedenheit am Arbeitsplatz anzusehen sind. Zwei Untersuchungen prüfen, ob Irrationalität invers mit emotionaler Intelligenz korreliert und wie beide Konstrukte mit Lebens- und Arbeitszufriedenheit verbunden sind. Studie 1 (N = 136) bestätigt an Studierenden die inverse Beziehung zwischen irrationalen Kognitionen und emotionalen Kompetenzen auf Basis von Selbsteinschätzungsskalen. Studie 2 (N = 115) repliziert dies an Vollzeitberufstätigen. Auch belegen beide Studien, dass emotionale Kompetenzen und in stärkerer Weise rationale Einstellungen mit erhöhter individueller Arbeits- und Lebenszufriedenheit verbunden sind. Dies spricht dafür, irrationales Denken als kognitive Variable im Kontext emotionaler Kompetenzen in der Personalforschung zu berücksichtigen.
Interannual variability of the global carbon cycle (1992–2005) inferred by inversion of atmospheric CO2 and δ13CO2 measurements
Authors: Rayner P. J. , Law R. M. , Allison C. E. , Francey R. J. , Trudinger C. M. , Pickett‐Heaps C.
Published: July 2008

We present estimates of the surface sources and sinks of CO2 for 1992–2005 deduced from atmospheric inversions. We use atmospheric CO2 records from 67 sites and 10 δ13CO2 records. We use two atmospheric models to increase the robustness of the results. The results suggest that interannual variability is dominated by the tropical land. Statistically significant variability in the tropical Pacific supports recent ocean modeling studies in that region. The northern land also shows significant variability. In particular, there is a large positive anomaly in 2003 in north Asia, which we associate with anomalous biomass burning. Results using δ13CO2 and CO2 are statistically consistent with those using only CO2, suggesting that it is valid to use both types of data together. An objective analysis of residuals suggests that our treatment of uncertainties in CO2 is conservative, while those for δ13CO2 are optimistic, highlighting problems in our simple isotope model. Finally, δ13CO2 measurements offer a good constraint to nearby land regions, suggesting an ongoing value in these measurements for studies of interannual variability.
A new international geostationary electron model: IGE‐2006, from 1 keV to 5.2 MeV
Authors: Sicard‐Piet A. , Bourdarie S. , Boscher D. , Friedel R. H. W. , Thomsen M. , Goka T. , Matsumoto H. , Koshiishi H.
Published: July 2008

Département Environnement Spatial, Office National d'Etudes et de Recherches Aérospatiales (ONERA) has been developing a model for the geostationary electron environment since 2003. Until now, this model was called Particle ONERA‐LANL Environment (POLE), and it is valid from 30 keV up to 5.2 MeV. POLE is based on the full complement of Los Alamos National Laboratory geostationary satellites, covers the period 1976–2005, and takes into account the solar cycle variation. Over the period 1976 to present, four different detectors were flown: charged particle analyzer (CPA), synchronous orbit particle analyzer (SOPA), energetic spectra for particles (ESP), and magnetospheric plasma analyzer (MPA). Only the first three were used to develop the POLE model. Here we extend the energy coverage of the model to low energies using MPA measurements. We further include the data from the Japanese geostationary spacecraft, Data Relay Test Satellite (DRTS). These data are now combined into an extended geostationary electron model which we call IGE‐2006.
Use of crop simulation models to evaluate limited irrigation management options for corn in a semiarid environment
Authors: Saseendran S. A. , Ahuja L. R. , Nielsen D. C. , Trout T. J. , Ma L.
Published: July 2008

Increasing competition for land and water resources due to increasing demands from rapid population growth calls for increasing water use efficiency of irrigated crops. It is important to develop location‐specific agronomic practices to maximize water use efficiency (WUE). Adequately calibrated and validated agricultural systems models provide a systems approach and a fast alternative method for developing and evaluating agronomic practices that can utilize technological advances in limited irrigation agriculture. The objectives of this study were to (1) calibrate and validate the CERES‐maize model under both dryland and irrigated corn (Zea mays L.) production in northeastern Colorado and (2) use the model with a long‐term weather record to determine (1) optimum allocation of limited irrigation between vegetative and reproductive growth stages and (2) optimum soil water depletion level for initiating limited irrigation. The soil series was a Rago silt loam, and the initial water content on 1 January of each year was equal to field capacity in the upper 300 mm and half of the field capacity below this depth. Optimum production and WUE with minimum nitrogen (N) losses were found when (1) a water allocation ratio of 40:60 or 50:50 (uniform) between vegetative and reproductive stages for irrigations up to 100 mm, and a ratio of 20:80 for irrigations above 100 mm was used; and (2) irrigation was initiated at 20% plant‐available water (PAW) (80% depletion). When available water for irrigation is limited to 100 mm, irrigating 50% of the area with 200 mm of water at 20:80 split irrigations between the vegetative and reproductive stages produced greater yield than irrigating 100% of the area with 100 mm water. Concepts developed in the study can potentially be adapted to other locations, climates, and crops. However, precise site‐specific recommendations need to be developed for each soil‐climate zone using the validated system model.
Seismic Tomography Experiment at Italy's Stromboli Volcano
Authors: Castellano Mario , Augusti Vincenzo , De Cesare Walter , Favali Paolo , Frugoni Francesco , Montuori Caterina , Sgroi Tiziana , De Gori Pasquale , Govoni Aladino , Moretti Milena , Patanè Domenico , Cocina Ornella , Zuccarello Luciano , Marsella Ennio , Aiello Gemma , Di Fiore Vincenzo , Ligi Marco , Bortoluzzi Giovanni , Ferrante Valentina , Marchetti Emanuele , Lacanna Giorgio , Ulivieri Giacomo
Published: July 2008

Stromboli Island, located in the southern Tyrrhenian Sea, is the emerged part (about 900 meters above sea level) of an approximately 3‐kilometer‐high stratovolcano. Its persistent Strombolian activity, documented for more than 2000 years, is sometimes interrupted by lava effusions or major explosions. Despite the number of recently published geophysical studies aimed at clarifying the volcano's eruption dynamics, the spatial extent and geometrical characteristics of its plumbing system remain poorly understood. In fact, knowledge of the inner structure and the zones of magma storage is limited to the upper few hundred meters of the volcanic edifice [Chouet et al., 2003; Mattia et al., 2004], and P and S wave velocity models are available only in restricted areas [Petrosino et al., 2002].
Earth Systems Science Agency Proposed
Authors: Showstack Randy
Published: July 2008

Seven former senior U.S. federal officials have called for the establishment of an independent Earth Systems Science Agency (ESSA) and for the next U.S. president and Congress to realign federal Earth sciences research and development programs.

The former officials—who include former heads of the U.S. National Oceanic and Atmospheric Administration (NOAA) and the U.S. Geological Survey (USGS)—issued their proposal for merging those two agencies into the ESSA, convening a commission to guide this realignment, and other measures, in a 4 July article in Science.
Geothermal inversion of Canadian Arctic ground temperatures and effect of permafrost aggradation at emergent shorelines
Authors: Taylor Alan E. , Wang Kelin
Published: July 2008

We apply traditional geothermal spectrum inversion to precision temperature logs and thermal conductivity from 10 wells in the Canadian Arctic Archipelago (75° to 81°N). Sites lie beyond the Holocene marine limit, and no effect of deep permafrost dynamics is expected. Ground surface temperature (GST) changes correlate with the Little Ice Age and Little Climatic Optimum with average amplitudes relative to 1980 of −2.7 K and +1.6 K, respectively. Results correlate broadly with similar reconstructions for this area and Greenland ice cap holes GRIP and Dye‐3 to the southeast. An offshore site in 244 m water yields a Little Ice Age seabed temperature amplitude of −0.7 K, suggesting a moderated climate impact on regional ocean temperatures. Nearshore boreholes where permafrost is aggrading owing to glacioisostatic emergence are excluded; we demonstrate that traditional inversion codes without latent heat of phase change predict the magnitude of the emergence signal but a timing far too recent.
Structural and biological characterization of a novel acutobin‐like enzyme isolated from the venom of the sharp‐nosed pit viper (Deinagkistrodon acutus)
Authors: Xin Yu , Dong Dexian , Chen Dezhao , Li Rongxiu
Published: July 2008

We previously reported the purification of a serine proteinase from the venom of the sharp‐nosed pit viper (Deinagkistrodon acutus) using a combination of affinity chromatography and ion‐exchange chromatography [Xin, Dong, Wang and Li, R. (2007) J. Chromatogr. B 859, 111–118]. The high fibrinogen‐clotting activity [2025 NIH (National Institutes of Health) units/mg] of this protein indicated that it may have great potential as a drug for treating thrombolysis. In order to systemically determine the purified protein's structure and activity, it was characterized using the following methods: MS, isoelectric focusing, deglycosylation analysis, amino acid composition analysis, peptide mass fingerprinting, N‐terminal amino acid sequencing, CD, hydrophobic‐site analysis and bioactivity assays. In addition, a fluorescence probe was synthesized and conjugated to the protein in order to analyse its active site. The results indicated that the protein is a novel acutobin‐like enzyme (designated acutobin II) with strong clotting and esterase activities and is composed of a 28 kDa peptide chain plus approx. 6 kDa of O‐linked glycan chains. The protein contains 249 amino acids and, remarkably, no tryptophan residues. The pI of the protein is 4.8±0.2. The protein's secondary structure is dominated by β‐sheets (49%) and random coils (43%), and its tertiary structure does not contain any metal ions or disulfide bonds and possesses only one hydrophobic pocket. Analysis revealed that the hydrophobic pocket is most likely the enzymatic active site.
High strength Ni–Zr binary ultrafine eutectic-dendrite composite with large plastic deformability
Authors: Park Jin Man , Kim Tae Eung , Sohn Sung Woo , Kim Do Hyang , Kim Ki Buem , Kim Won Tae , Eckert Jürgen
Published: July 2008

A Ni–8Zr high strength ultrafine eutectic-dendrite composite with large plasticity has been developed in the Ni–Zr binary eutectic system. The excellent mechanical properties are attributed to the specific heterogeneous microstructure with distinctly different length scales, i.e., micrometer-size ductile dendrites combined with an ultrafine eutectic matrix. The plastic deformation mainly proceeds through a shear banding mechanism. However, there is no significant shear localization due to the constraint effect of ductile solid solution Ni phases including dendrites and/or alternating lamellar layers. Furthermore, excessive shear stress and accumulated shear strain can be effectively released and accommodated by delocalization and multiplication of shear bands.
Community structure of a rhodolith bed from cold-temperate waters (southern Australia)
Authors: Harvey A. S. , Bird F. L.
Published: July 2008

Rhodolith beds are aggregations of free-living non-geniculate coralline red algae (Corallinales, Rhodophyta), with a high biodiversity of associated organisms. This is the first detailed study of a rhodolith-bed community from the cold-temperate waters of southern Australia. This bed, located at 1–4-m depth in Western Port, Victoria, is composed of four rhodolith-forming species (Hydrolithon rupestre (Foslie) Penrose, Lithothamnion superpositum Foslie, Mesophyllum engelhartii (Foslie) Adey and Neogoniolithon brassica-florida (Harvey) Setchell & Mason). M. engelhartii has a foliose growth form and the other three species have fruticose growth forms. Detailed descriptions are provided for all species, allowing reliable identification. Comparisons with other rhodolith beds and reported rhodolith-forming species, both in Australia and worldwide, are also provided. The invertebrate cryptofaunal community was quantified for two rhodolith-forming species. The density of cryptofauna inhabiting foliose and fruticose rhodolith growth forms did not differ significantly and neither did abundance of individual phyla. Mean density of fauna was 0.4 invertebrates cm–3, the majority of which were polychaete worms. Comparisons of fauna associated with other rhodolith beds are also provided. A study of the vitality of the rhodolith bed showed dead rhodoliths are more abundant than live rhodoliths. Possible reasons for reduced bed vitality are explored.
Short Communication. Some wild bamboo clumps contain more than one genet
Authors: Franklin Donald C. , Kaneko Shingo , Yamasaki Nozomi , Isagi Yuji
Published: July 2008

In clumping clonal plants, the often discrete nature of clumps may be enhanced by competition among genets. We examined the genetic composition of clumps of Bambusa arnhemica F.Muell., a bamboo from northern Australia, by analysis of microsatellites. Three of ten clumps were demonstrably multiclonal, containing a minimum of two, four and five genets, respectively. This raises intriguing questions about the development of clumps and suggests that intergenet competition may at times be overwhelmed by the benefits of coloniality in B. arnhemica.
Amazon River enhances diazotrophy and carbon sequestration in the tropical North Atlantic Ocean
Authors: Subramaniam A. , Yager P. L. , Carpenter E. J. , Mahaffey C. , Björkman K. , Cooley S. , Kustka A. B. , Montoya J. P. , Sañudo-Wilhelmy S. A. , Shipe R. , Capone D. G.
Published: July 2008

The fresh water discharged by large rivers such as the Amazon is transported hundreds to thousands of kilometers away from the coast by surface plumes. The nutrients delivered by these river plumes contribute to enhanced primary production in the ocean, and the sinking flux of this new production results in carbon sequestration. Here, we report that the Amazon River plume supports N
2
fixation far from the mouth and provides important pathways for sequestration of atmospheric CO
2
in the western tropical North Atlantic (WTNA). We calculate that the sinking of carbon fixed by diazotrophs in the plume sequesters 1.7 Tmol of C annually, in addition to the sequestration of 0.6 Tmol of C yr
−1
of the new production supported by NO
3
delivered by the river. These processes revise our current understanding that the tropical North Atlantic is a source of 2.5 Tmol of C to the atmosphere [Mikaloff-Fletcher SE,
et al.
(2007) Inverse estimates of the oceanic sources and sinks of natural CO
2
and the implied oceanic carbon transport.
Global Biogeochem Cycles
21, doi:10.1029/2006GB002751]. The enhancement of N
2
fixation and consequent C sequestration by tropical rivers appears to be a global phenomenon that is likely to be influenced by anthropogenic activity and climate change.
Environmental regulation in a network of simulated microbial ecosystems
Authors: Williams Hywel T. P. , Lenton Timothy M.
Published: July 2008

The Earth possesses a number of regulatory feedback mechanisms involving life. In the absence of a population of competing biospheres, it has proved hard to find a robust evolutionary mechanism that would generate environmental regulation. It has been suggested that regulation must require altruistic environmental alterations by organisms and, therefore, would be evolutionarily unstable. This need not be the case if organisms alter the environment as a selectively neutral by-product of their metabolism, as in the majority of biogeochemical reactions, but a question then arises: Why should the combined by-product effects of the biota have a stabilizing, rather than destabilizing, influence on the environment? Under certain conditions, selection acting above the level of the individual can be an effective adaptive force. Here we present an evolutionary simulation model in which environmental regulation involving higher-level selection robustly emerges in a network of interconnected microbial ecosystems. Spatial structure creates conditions for a limited form of higher-level selection to act on the collective environment-altering properties of local communities. Local communities that improve their environmental conditions achieve larger populations and are better colonizers of available space, whereas local communities that degrade their environment shrink and become susceptible to invasion. The spread of environment-improving communities alters the global environment toward the optimal conditions for growth and tends to regulate against external perturbations. This work suggests a mechanism for environmental regulation that is consistent with evolutionary theory.
A γ-secretase inhibitor and quinacrine reduce prions and prevent dendritic degeneration in murine brains
Authors: Spilman Patricia , Lessard Pierre , Sattavat Mamta , Bush Clarissa , Tousseyn Thomas , Huang Eric J. , Giles Kurt , Golde Todd , Das Pritam , Fauq Abdul , Prusiner Stanley B. , DeArmond Stephen J.
Published: July 2008

In prion-infected mice, both the Notch-1 intracellular domain transcription factor (NICD) and the disease-causing prion protein (PrP
Sc
) increase in the brain preceding dendritic atrophy and loss. Because the drug LY411575 inhibits the γ-secretase-catalyzed cleavage of Notch-1 that produces NICD, we asked whether this γ-secretase inhibitor (GSI) might prevent dendritic degeneration in mice with scrapie. At 50 d postinoculation with Rocky Mountain Laboratory (RML) prions, mice were given GSI orally for 43–60 d. Because we did not expect GSI to produce a reduction of PrP
Sc
levels in brain, we added quinacrine (Qa) to the treatment regimen. Qa inhibits PrP
Sc
formation in cultured cells. The combination of GSI and Qa reduced PrP
Sc
by ≈95% in the neocortex and hippocampus but only ≈50% in the thalamus at the site of prion inoculation. The GSI plus Qa combination prevented dendritic atrophy and loss, but GSI alone did not. Even though GSI reduced NICD levels to a greater extent than GSI plus Qa, it was unable to prevent dendritic degeneration. Whether a balance between NICD and dendrite growth-stimulating factors was achieved with GSI plus Qa but not GSI alone remains to be determined. Although the combination of GSI and Qa diminished PrP
Sc
in the brains of RML-infected mice, GSI toxicity prevented us from being able to assess the effect the GSI plus Qa combination on incubation times. Whether less toxic GSIs can be used in place of LY411575 to prolong survival remains to be determined.
ATP negatively regulates the initiator protein of
Vibrio cholerae
chromosome II replication
Authors: Duigou Stéphane , Yamaichi Yoshiharu , Waldor Matthew K.
Published: July 2008

Vibrio cholerae
, the agent of cholera, has two circular chromosomes. In bacteria that contain a single chromosome, initiation of chromosome DNA replication is mediated by DnaA, a AAA+ ATPase that unwinds the origin of replication. There is little knowledge regarding initiation of chromosome replication in bacteria with more than one chromosome. Here, we purified
V. cholerae
DnaA and RctB, which have been implicated in the replication of
V. cholerae
chromosome II, and characterized their activities
in vitro
. We found that RctB has origin-specific unwinding activity and can melt the origin of chromosome II (
oriCIIvc
) but not the origin of chromosome I (
oriCIvc
); conversely, DnaA promoted the unwinding of
oriCIvc
and not
oriCIIvc
. The activity of DnaA and several plasmid initiator proteins is stimulated by ATP binding. We found that RctB bound and hydrolyzed ATP even though RctB lacks any apparent ATP-binding motifs. However, we unexpectedly found that ATP inhibited the
oriCIIvc
binding activity of RctB, suggesting that the ATP-bound form of RctB cannot initiate replication of chromosome II. Supporting this idea, we identified an RctB mutant that does not bind ATP and found that expression of this ATP-blind RctB mutant in
V. cholerae
leads to significant overinitiation of chromosome II and marked inhibition of
V. cholerae
growth. These observations suggest that the rules that license the replication of the two
V. cholerae
chromosomes differ.
S-nitrosylation/activation of COX-2 mediates NMDA neurotoxicity
Authors: Tian Jing , Kim Sangwon F. , Hester Lynda , Snyder Solomon H.
Published: July 2008

Glutamate/N-methyl-d-aspartate (NMDA) receptor-mediated neurotoxicity involves cyclooxygenase (COX)-2. We demonstrate that this neurotoxicity reflects activation of COX-2 byS-nitrosylation after selective binding of neuronal nitric oxide synthase (nNOS) to COX-2. nNOS, via its PDZ domain, binds COX-2 with the generated NOS-nitrosylating and activating the enzyme. Selective disruption of nNOS—COX-2 binding prevents NMDA neurotoxicity.
Anomalous arterial supply to the gallbladder from the superior mesenteric artery: angiography and computed tomography findings in two cases
Authors: Katada Y. , Kishino M. , Ishihara K. , Takeguchi T. , Shibuya H.
Published: July 2008

The arterial supply of the gallbladder usually arises from the right hepatic artery. Other origins include the left, proper, and common hepatic arteries. We report cases of the cystic artery arising from the superior mesenteric artery and arising from the dorsal pancreatic artery originating in turn from the superior mesenteric artery, as demonstrated by angiography and computed tomography.
Correlation between depth of myocardial bridging and coronary angiography findings
Authors: Elmali M. , Soylu K. , Gulel O. , Bayrak I. K. , Koprulu D. , Diren H. B. , Celenk C.
Published: July 2008

Background: Myocardial bridging (MB) is a congenital anomaly in which a segment of coronary artery is surrounded by myocardium.

Purpose: To investigate the correlation between muscle thickness over the tunneled coronary artery (depth) in MB and the presence of milking effect (ME) and systolic narrowing ratio in catheter angiography (CA).

Material and Methods: The records of 36 patients who underwent a coronary computed tomography angiography (CTA) and following CA examination for suspicious ischemic coronary artery disease, between March 2005 and September 2007, were retrospectively evaluated. According to the depth of MB on CTA, patients were grouped into four groups: group 1, <1 mm; group 2, 1– <2 mm; group 3, 2– <4 mm; group 4, ≥4 mm. The presence of milking effect, systolic narrowing ratio, and atherosclerotic stenosis at CA were recorded. CTA and CA results were then compared to evaluate the correlation.

Results: In total, ME was found in 15 arteries at CA (42%). There was no ME in group 1; it was present in 11% of group 2, 67% of group 3, and 100% of group 4. Starting from group 3, the percentage of likelihood of seeing the milking effect was 77%, and the percentage of systolic narrowing was between 30 and 70%. There was a significant correlation between depth of MB and systolic narrowing ( P<0.01), while no significant correlation between length of MB and systolic narrowing was found ( P=0.32). In seven of the 36 patients (group 1, 0; group 2, 1; group 3, 3; group 4, 3), clinical findings were related to pure MB.

Conclusion: The depth of MB is positively related to coronary narrowing and clinical ischemic findings.
All-in-one magnetic resonance arthrography of the shoulder in a vertically open magnetic resonance unit
Authors: Vandevenne J. E. , Vanhoenacker F. , Beaulieu C. F. , Bergman A. G. , Butts Pauly K. , Dillingham M. F. , Lang P. K.
Published: July 2008

Background: Magnetic resonance (MR) arthrography frequently involves joint injection under imaging guidance followed by MR imaging in static positions.

Purpose: To evaluate if MR arthrography of the shoulder joint can be performed in a comprehensive fashion combining the MR-guided injection procedure, static MR imaging, and dynamic motion MR imaging in a single test.

Material and Methods: Twenty-three shoulder joints were injected with Gd-DTPA2- under MR guidance. Static MR imaging was performed and included a three-point Dixon method to achieve water-selective images. Dynamic motion MR imaging with and without applying pressure to the upper arm was used to evaluate glenohumeral joint instability. In 10 cases, surgical correlation was available.

Results: The all-in-one MR arthrography technique was successful in all patients, and took an average time of 65 min. All but one glenohumeral injection procedure were performed with a single needle pass, and no complications were observed. Out of eight labrum tears seen with static MR imaging, seven were confirmed at surgery. In 10 cases, dynamic motion MR imaging correlated well with the surgeon's intraoperative evaluation for presence and direction of instability.

Conclusion: MR arthrography of the shoulder joint using a vertically open magnet can be performed as a single comprehensive test, including the injection and the static and dynamic motion MR imaging. Good diagnostic accuracy for intraarticular lesions and glenohumeral instability was found in a small sample.
Role of shielding in modelling cryogenic deuterium pellet ablation
Authors: Gál K. , Belonohy É. , Kocsis G. , Lang P.T. , Veres G.
Published: July 2008

For the better characterization of pellet ablation, the numerical LLP code has been enhanced by combining two relevant shielding mechanisms: that of the spherically expanding neutral cloud surrounding the pellet and that of the field elongated ionized material forming a channel flow. In contrast to our expectation the presence of the channel flow can increase the ablation rate although it reduces the heat flux travelling through it. The contribution of the different shielding effect in the ablation process is analysed for several pellet and plasma parameters and an ablation rate scaling is presented based on simple regression in the ASDEX Upgrade pellet and plasma parameter range. Finally the simulated results are compared with experimental data from typical ASDEX Upgrade discharges.
Generation of multilayered structures for biomedical applications using a novel tri-needle coaxial device and electrohydrodynamic flow
Authors: Ahmad Z , Zhang H.B , Farook U , Edirisinghe M , Stride E , Colombo P
Published: July 2008

In this short communication, we describe the scope and flexibility of using a novel device containing three coaxially arranged needles to form a variety of novel morphologies. Different combinations of materials are subjected to controlled flow through the device under the influence of an applied electric field. The resulting electrohydrodynamic flow allows us to prepare double-layered bubbles, porous encapsulated threads and nanocapsules containing three layers. The ability to process such multilayered structures is very significant for biomedical engineering applications, for example, generating capsules for drug delivery, which can provide multistage controlled release.
Pain catastrophizing: a dimensional concept analysis
Authors: Martorella Géraldine , Côté José , Choinière Manon
Published: July 2008

Title.  Pain catastrophizing: a dimensional concept analysis.

Aim.  This paper is a report of a concept analysis of pain catastrophizing.

Background.  The importance of pain catastrophizing in the experience of pain and development of chronic pain has been demonstrated. It has been described as a tendency to have a fixation about pain and to feel unable to deal with pain.

Data sources.  Fifty‐one papers containing the keyword ‘pain catastrophizing’ were selected from the Medline, Embase and Psycinfo indexes between 1996 and 2008. Dimensional analysis methodology was used to make explicit the ways in which the concept is constructed and used. The themes of this approach seem to contribute to the understanding of both nurse and client perspectives.

Results.  The literature on ‘pain catastrophizing’ seems to reach a level of middle‐range explanatory theory. The focus is on specifying relationships between pain catastrophizing and two or more concepts, and on validating the theoretical hypotheses of ‘communal coping’ as opposed to ‘hypervigilance’. The predominance of correlational and cross‐sectional studies testifies to this. The concept’s definition includes the curative and preventive approaches. However, only the professional perspective seems to be reflected in the concept’s terminology.

Conclusion.  Nursing theories and qualitative research seem to be avenues for the comprehension of the phenomenon and the broadening of perspectives. They may bring not only a new but also a unique perspective. Nevertheless, the current state of knowledge on pain catastrophizing is important to nurses as they could influence greatly the timing of interventions and prevention of chronic pain.
Women’s positions during the second stage of labour: views of primary care midwives
Authors: De Jonge Ank , Teunissen Doreth A.M. , Van Diem Mariet Th. , Scheepers Peer L.H. , Lagro‐Janssen Antoine L.M.
Published: July 2008

Title.  Women’s positions during the second stage of labour: views of primary care midwives.

Aim.  This paper is a report of a study to explore the views of midwives on women’s positions during the second stage of labour.

Background.  Many authors recommend encouraging women to use positions that are most comfortable to them. Others advocate encouragement of non‐supine positions, because offering ‘choice’ is not enough to reverse the strong cultural norm of giving birth in the supine position. Midwives’ views on women’s positions have rarely been explored.

Method.  Six focus groups were conducted in 2006–2007 with a purposive sample of 31 midwives. The data were interpreted using Thachuk’s models of informed consent and informed choice.

Findings.  The models were useful in distinguishing between two different approaches of midwives to women’s positions during labour. When giving informed consent, midwives implicitly or explicitly ask a woman’s consent for what they themselves prefer. When offering informed choice, a woman’s preference is the starting point, but midwives will suggest other options if this is in the woman’s interest. Obstetric factors and working conditions are reasons to deviate from women’s preferences.

Conclusions.  To give women an informed choice about birthing positions, midwives need to give them information during pregnancy and discuss their position preferences. Women should be prepared for the unpredictability of their feelings in labour and for obstetric factors that may interfere with their choice of position. Equipment for non‐supine births should be more midwife‐friendly. In addition, midwives and students need to be able to gain experience in assisting births in non‐supine positions.
Presence of patients’ families during cardiopulmonary resuscitation: physicians’ and nurses’ opinions
Authors: Demir Fatma
Published: July 2008

Title.  Presence of patients’ families during cardiopulmonary resuscitation: physicians’ and nurses’ opinions.

Aim.  This paper is a report of a study to determine the opinions of physicians and nurses who work in a university hospital intensive care unit and emergency department about the presence of patients’ families during cardiopulmonary resuscitation in these units.

Background.  Healthcare professionals have conflicting opinions about the presence of patients’ families during cardiopulmonary resuscitation. Families who are allowed to be present have less fear and worry, feel they have supported their family member and are able to cope more easily.

Method.  The data for this descriptive questionnaire study were collected between November 2006 and January 2007. The respondents were 62 physicians and 82 nurses who worked in an emergency department or in cardiology or anaesthesia intensive care units in Turkey. The data were collected using a questionnaire and the responses summarized using frequencies and percentages. The chi‐squared test was performed to test for differences in the opinion by profession, educational level, or number of years of working experience in the profession.

Findings.  The response rate was 79%. Of the respondents, 82·6% did not think it was appropriate for patients’ families to be present during cardiopulmonary resuscitation. The most common concerns mentioned were that the family would interfere with the team’s activities (56·3%) and that resuscitation is a very traumatic procedure (43·6%).

Conclusion.  Policies need to be developed regarding this topic because the absence of policy can cause misunderstanding and differences in practice. Further research is needed to determine what public education is needed to facilitate implementation of such policies.
Quantitative determination of the reduction of phototoxicity and photobleaching by controlled light exposure microscopy
Authors: HOEBE R.A. , VAN DER VOORT H.T.M. , STAP J. , VAN NOORDEN C.J.F. , MANDERS E.M.M.
Published: July 2008

Phototoxicity and photobleaching are major limitations in live‐cell fluorescence microscopy. They are caused by fluorophores in an excited singlet or triplet state that generate singlet oxygen and other reactive oxygen species. The principle of controlled light exposure microscopy (CLEM) is based on non‐uniform illumination of the field of view to reduce the number of excited fluorophore molecules. This approach reduces phototoxicity and photobleaching 2‐ to 10‐fold without deteriorating image quality. Reduction of phototoxicity and photobleaching depends on the fluorophore distribution in the studied object, the optical properties of the microscope and settings of CLEM electronics. Here, we introduce the CLEM factor as a quantitative measure of reduction in phototoxicity and photobleaching. Finally, we give a guideline to optimize the effect of CLEM without compromising image quality.
Preservation of ultrastructure and immunoreactivity in cryosections of brain tissue stored in a sucrose‐gelatin solution at freezing temperatures
Authors: AKAGI T. , ISHIDA K. , TOHNO H. , HANASAKA T.
Published: July 2008

We evaluated the preservation of ultra‐structure and immunoreactivity in cryosections of central nervous system tissue mounted with and stored in a sucrose–gelatin solution for one month at −20°C or −80°C. The ultra‐structure of synaptic structure in these sections was well preserved and comparable to that of freshly cut cryosections. Quantitative analysis of mitochondrial ultra‐structure demonstrated gradually lower degrees of preservation in sections stored at −20°C and −80°C compared with that in freshly cut sections. We observed distinct metabotropic glutamate receptor 1 (mGluR1)‐immunogold labelling at peri‐synaptic sites in freshly cut sections and also in those stored at −20°C and −80°C. Quantitative analysis of mGluR1 immunoreactivity revealed that the total number of immunogold particles per synapse and the number of non‐specifically bound particles were similar under all three conditions. However, the percentage of gold particles bound to a specific synaptic region was greatest in freshly cut sections (79.0%) and progressively lower in sections stored at −20°C (76.1%), in which sections were not frozen, and in sections stored at −80°C (68.0%). These data indicate that ultra‐thin cryosections may be conveniently stored in a sucrose–gelatin solution at −20°C for cryoultramicrotomy‐immunolabelling.
Application of elemental microanalysis to elucidate the role of spherites in the digestive gland of the helicid snail Chilostoma lefeburiana
Authors: DELAKORDA S. LIPOVŠEK , LETOFSKY‐PAPST I. , NOVAK T. , GIOVANNELLI M. , HOFER F. , PABST M.A.
Published: July 2008

In this case study we present an application of different analytical electron microscopic methods in biology, to elucidate their usefulness in such investigations. Using analytical electron microscopy, spherites in the digestive gland cells of the helicid snail Chilostoma lefeburiana were examined at three stages: just before the non‐feeding period of over‐wintering in November, in the middle of over‐wintering in February and at its end in March. A detailed characterization of changes in the elemental composition of the spherites was characterized by a combination of transmission electron microscopy (TEM), energy dispersive x‐ray spectroscopy (EDXS), electron energy‐loss spectroscopy (EELS) and energy filtering TEM (EFTEM). During over‐wintering, the spherites passed the following changes. Before over‐wintering in November, they consisted of striking concentric layers of electron‐dense and electron‐lucent zones, while in February and March they showed clear empty zones between materials of different electron density. In November spherites, C, O, Ca, P, Cl, Fe, Si, Na, K, Mg and S were detected, whereas in February ones C, O, N, Cl, Si and S were found and only C, O, N, Si and Cl were detected in March spherites. It is suggested that the elements missing in February and March were used in different physiological processes during over‐wintering, like (1) the maintenance of the appropriate elemental composition of the internal environment, (2) accumulation of non‐toxic waste materials that cannot be metabolized and (3) avoiding potential intoxication by contamination with toxic metals.