bluuebunny/crossref_metadata_2025 huggingface dataset:
Plant stress proteins of the thaumatin‐like family discovered in animals
Authors: Brandazza Anna , Angeli Sergio , Tegoni Mariella , Cambillau Christian , Pelosi Paolo
Published: July 2004

Thaumatin‐like proteins (TLPs) are polypeptides of about 200 residues synthesized by plants in response to fungal infection. In addition to the exceptionally strong sweet taste exhibited by some members, they are also reported to be endowed with endo‐β‐1,3‐glucanase activity and α‐amylase inhibiting properties. However, the detailed mechanism of their antifungal action is not completely understood. So far, TLPs have only been described in plants, with several members of the family expressed in the same species. Here, for the first time in animals, we report the identification of two genes encoding members of the thaumatin‐like proteins family in the desert locust Schistocerca gregaria and show their expression in different parts of the body. Southern blot and Western blot experiments revealed the presence of orthologous genes and their expression products in the related species Locusta migratoria. A search through the available genomes yielded similar sequences in the nematode Caenorhabditis but not in Drosophila and other insects. A three‐dimensional model of S. gregaria TLP suggests a glucanase function. As in plants, TLPs could play a defense role in insects against pathogens.
Multiple terminal uridylyltransferases of trypanosomes
Authors: Aphasizhev Ruslan , Aphasizheva Inna , Simpson Larry
Published: July 2004

The transferase activities that add uridylyl residues to RNA have been reported in several unicellular and metazoan organisms. Thus far, the two terminal uridylyltransferases (TUTases) involved in uridine insertion/deletion mRNA editing in mitochondria of trypanosomes were the only known enzymes with confirmed UTP specificity. Here, we demonstrate that protein sequences of editing TUTases may be used to predict novel UTP‐specific enzymes by data mining. The highest‐scoring open reading frame from Trypanosoma brucei was expressed and recombinant protein purified. This enzyme catalyzes a processive UMP incorporation and is not localized to the mitochondria suggesting a non‐editing biological function.
Three distinct Arabidopsis hemoglobins exhibit peroxidase‐like activity and differentially mediate nitrite‐dependent protein nitration
Authors: Sakamoto Atsushi , Sakurao Sho-hei , Fukunaga Keiko , Matsubara Toshiyuki , Ueda-Hashimoto Manami , Tsukamoto Shigefumi , Takahashi Misa , Morikawa Hiromichi
Published: July 2004

All plants examined to date possess non‐symbiotic hemoglobin whose physiological role remains unclear. The present study explored the catalytic function of three representative classes of the plant hemoglobin from Arabidopsis thaliana: AtGLB1, AtGLB2, and AtGLB3. Purified recombinant proteins of these hemoglobins displayed hydrogen peroxide‐dependent oxidation of several peroxidase substrates that was sensitive to cyanide, revealing intrinsic peroxidase‐like activity. In the presence of nitrite and hydrogen peroxide, AtGLB1 was the most efficient at mediating tyrosine nitration of its own and other proteins via the formation of reactive nitrogen species as a result of nitrite oxidation. AtGLB1 mRNA significantly accumulated in Arabidopsis seedlings exposed to nitrite, supporting the physiological relevance of its function to nitrite and nitrite‐derived reactive nitrogen species.
Survival of reared and wild Atlantic salmon smolts: size matters more in bad years
Authors: Saloniemi I. , Jokikokko E. , Kallio-Nyberg I. , Jutila E. , Pasanen P.
Published: July 2004

We compared the marine survival of Carlin-tagged wild and hatchery-reared Atlantic salmon smolts of the Simojoki river, northern Baltic Sea. All the reared and released smolts were the offspring of native spawners returning to the river. Reared smolts were adipose-fin-clipped and released from the hatchery several weeks before tagging. The wild and reared smolts were simultaneously caught and tagged at a smolt trap located at the Simojoki river mouth. The study was conducted in two years, 1991 and 1993, when post-smolt survival in the Baltic Sea was different. Tags were returned by fishermen and return rates were used to estimate the survival of the smolt groups. We applied generalized linear models with survival as response variable and the year, origin, and smolt size as explanatory variables. On average, wild smolts had a 4.5 times higher survival rate than reared fish of the same smolt size. The difference in observed tag recovery rates as such was only about twofold or less, as the larger size of the reared smolts compared with the wild ones compensated for their lower survival rate. The better survival of wild than reared smolts was more pronounced in the low-survival year (1993 smolt year class) than in the high-survival year (1991 smolt year class).
Fear conditioning is impaired in adult rats by ethanol doses that do not affect periadolescents
Authors: Land Cantey , Spear Norman E.
Published: July 2004

Adolescent rats and humans exhibit physiological, behavioral, and cognitive differences compared to their adult counterparts. These differences are apparent also in reactions to psychoactive drugs, such as ethanol. Recent studies have shown that though less sensitive to several behavioral indices of intoxication by ethanol, adolescent rats are more sensitive to the cognition‐impairing effects of ethanol. Ethanol's effects, in the present experiment, were assessed in terms of a fear conditioning test not previously used in comparison of adult and adolescent Sprague–Dawley albino rats. Separate groups of both ages were given intraperitoneal (i.p.) ethanol before or after tone–shock conditioning. This task features a hippocampus‐independent component, learned freezing to a tone, and a hippocampus‐dependent component, learned freezing to context. Post‐training ethanol had no effect on retention in either age, but pre‐acquisition ethanol impaired adult learning more than adolescent learning, as indexed by the expression of fear at the test. Blood alcohol was equivalent in adolescents and adults at a dose that produced cognitive discrepancies. Unlike other reports, these experiments demonstrate that adolescents may not be more sensitive to ethanol's effects in all cases of learning.
Research on Competitive Dynamics: Recent Accomplishments and Future Challenges
Authors: Ketchen David J. , Snow Charles C. , Hoover Vera L.
Published: July 2004

Understanding the nature and consequences of the competitive dynamics among firms is a key objective of the strategic management field. We review recent developments in six research streams relevant to competitive dynamics: competitive action and response, first-mover advantage, co-opetition, multipoint competition, strategic groups, and regional clusters. As a first step toward filling gaps in knowledge identified in our review, we provide suggestions for future inquiry within each research stream. We also describe opportunities for conceptual integration across the streams that could significantly advance the understanding of competitive dynamics. © 2004 Elsevier Inc. All rights reserved.
Corporate Political Activity: A Review and Research Agenda
Authors: Hillman Amy J. , Keim Gerald D. , Schuler Douglas
Published: July 2004

Corporate political activities, or corporate attempts to shape government policy in ways favorable to the firm, are commonly employed by firms across countries. We review recent scholarly work from management, political science, economics and sociology in the area of corporate political activity (CPA), paying particular attention to the literature published since Shaffer’s [Shaffer, B. 1995. Firm-level responses to government regulation: Theoretical and research approaches. Journal of Management, 21: 495–514] review. To integrate this literature we provide a model of the antecedents of CPA, the different types of CPA, how firms organize to implement CPA and the outcomes of CPA both for public policy and firm performance. We conclude our review by proposing an agenda for future research in the area.
The Social Context of Performance Appraisal: A Review and Framework for the Future
Authors: Levy Paul E. , Williams Jane R.
Published: July 2004

Performance appraisal research over the last 10 years has begun to examine the effects of the social context on the appraisal process. Drawing from previous theoretical work, we developed a model of this process and conducted a systematic review of the relevant research. This review of over 300 articles suggests that as a field we have become much more cognizant of the importance of the social context within which the performance appraisal process operates. First, research has broadened the traditional conceptualization of performance appraisal effectiveness to include and emphasize ratee reactions. Second, the influence that the feedback environment or feedback culture has on performance appraisal outcomes is an especially recent focus that seems to have both theoretical and applied implications. Finally, there appears to be a reasonably large set of distal variables such as technology, HR strategies, and economic conditions that are potentially important for understanding the appraisal process, but which have received very little research attention. We believe that the focus of recent performance appraisal research has widespread implications ranging from theory development and enhancement to practical application.
Effekte aLtErNiErEnDeR Schreibung auf Benennungs- und lexikalische Entscheidungslatenzen im Deutschen
Authors: Huckauf Anke , Placke Lars , Heller Dieter
Published: July 2004

Zusammenfassung. Die Wirkung alternierender Schreibung auf Benennungen und lexikalische Entscheidungen wurde im Hinblick auf die Frage untersucht, inwieweit die Störungen alle Wörter gleichermaßen oder insbesondere seltene Wörter betreffen. Im Gegensatz zu der unklaren Befundlage in englischsprachigen Untersuchungen zeigte sich in der vorliegenden Versuchsserie mit reguläreren deutschen Wörtern, dass die Erkennbarkeit seltener Wörter in beiden Aufgaben stärker durch alternierende Schreibung beeinträchtigt wird als die häufiger Wörter. Innerhalb eines dual route-Ansatzes weist dies darauf hin, dass durch die alternierende Schreibung insbesondere auch Prozesse einer indirekten nichtlexikalischen Route beeinträchtigt sind. Um die generellen Ursachen für einen störenden Einfluss alternierender Schreibung auf die Wortverarbeitung zu untersuchen, wurden zusätzlich gezielte Buchstabengruppen farbig markiert. Diese Markierung verringerte den störenden Effekt der alternierenden Schreibung, was als Hinweis interpretiert wird, dass die Information über die Abfolge der Buchstaben durch alternierende Schreibung gestört wird. Dabei spielte es jedoch keine Rolle, ob die markierten Buchstabengruppen Silben oder zufälligen Einheiten entsprachen. Dies deutet darauf hin, dass die Silbe für die Wortverarbeitung im Deutschen von untergeordneter Bedeutung zu sein scheint.
Fantasie und Wirklichkeit - Erinnerungsqualitäten von erlebten und erfundenen Geschichten
Authors: Sporer Siegfried Ludwig , Küpper Beate
Published: July 2004

Zusammenfassung. Im Zentrum dieser Untersuchung steht die Frage, wodurch wir tatsächlich Erlebtes von lediglich Vorgestelltem, durch Gedanken oder unsere Fantasie Geschaffenem, unterscheiden können. Diese und ähnliche Fragestellungen werden im Rahmen des Realitätsüberwachungsansatzes untersucht, allerdings mit relativ einfachen Handlungssequenzen. Ziel dieser Untersuchung war, diesen Ansatz auf komplexere autobiografische Erlebnisse auszudehnen und seine Brauchbarkeit bei der Diskrimination von erlebten vs. erfundenen Erlebnissen zu überprüfen. Wir ließen 100 Studierende, Schüler und Auszubildende innerhalb einer Woche je eine auf einem tatsächlichen, “besonderen“ Erlebnis beruhende und eine frei erfundene Geschichte - in ausbalancierter Reihenfolge - niederschreiben. Im Anschluss daran sollten die Verfasser die Geschichten anhand des Selbstbeurteilungsbogens von Erinnerungsqualitäten (SBEQ) - einer adaptierten Fassung von Johnson, Foley, Suengas und Raye’s (1988) Memory Characteristics Questionnaire - einschätzen. Die Ratings wurden getrennt für erlebte und erfundene Geschichten Faktorenanalysen unterzogen. Auf Grund theoretischer Vorüberlegungen und dieser Faktorenanalysen wurden acht Skalen von Erinnerungsqualitäten gebildet, die sich als Klarheit und Lebendigkeit, Sensorische Informationen, Räumlichkeit, Zeitangaben, Emotionen und Gefühle, Rekonstruierbarkeit, Realitätsnähe und Kognitive Operationen interpretieren lassen. Eine multivariate Varianzanalyse mit Wahrheitsstatus, Vorbereitung der Erzählung und Gechlecht der TeilnehmerInnen diskriminierte hochsignifikant zwischen erlebten und erfundenen Geschichten auf 6 der 8 Skalen. Die Zeit zur Vorbereitung der Erzählung hatte nur bei 2 Skalen eine Bedeutung. Die Ergebnisse werden in die theoretische Diskussion um Realitätsüberwachungsprozesse eingebettet.
Verbalisierende Reflexion und Lösungsgüte beim Entwurfsdenken
Authors: Hacker Winfried , Wetzstein Annekatrin
Published: July 2004

Zusammenfassung. In drei Experimentalstudien (N1 = 71, N2 = 73, N3 = 60) wurde der Einfluss unterschiedlicher Arten fragengestützter verbalisierender Reflexion auf eine Verbesserung der Lösungsgüte im Entwurfsproblemlösen untersucht. Kontrollgruppen hatten bei gleichem Zeitbudget ihre Lösungen zu überdenken, oder sie pausierten mit anschließender Möglichkeit zur Weiterarbeit. Signifikante und effektstarke Verbesserungen der Lösungsgüte traten nur beim verbalisierenden Beschreiben und Begründen der erzielten Lösungen mit einem “naiven” Partner und im geringerem Ausmaße auch ohne diesen auf. Die Aufforderungen zum Überdenken und zum Pausieren ergaben nachfolgend keine signifikanten Verbesserungen. Nach verbalisierender Reflexion werden häufiger als ohne diese Modifikationen am Entwurf vorgenommen, die vor allem neue Aspekte zur Lösung beisteuern. Zur Erklärung werden Beziehungen zu in der Literatur berichteten Veränderungen im Vorgehen (“analytisch“ ( Merz, 1969 ); “dialogisch“ ( Bartl & Dörner, 1998 ; Bertau, 1999 ) diskutiert.
Die Wortstammlänge beeinflusst kontrollierte, nicht aber automatische Gedächtnisprozesse im Wortstammergänzungsparadigma
Authors: Cüpper Lutz , Erdfelder Edgar
Published: July 2004

Zusammenfassung. Manche Methoden zur Erfassung verschiedener Gedächtnisprozesse setzen voraus, dass sich die Stärke der an Rekognitionsaufgaben beteiligten bewussten Erinnerungsprozesse nicht von den an Reproduktionsaufgaben beteiligten unterscheidet. Diese Kommensurabilitätsannahme scheint zwar zweifelhaft, ist bis jetzt aber empirisch nicht überprüft worden (vgl. Clark, 1999 ). Die Autoren zeigen, dass die Verlängerung von Wortstämmen in der Wortstammergänzungsaufgabe neben Rateprozessen auch bewusste Erinnerungsprozesse fördert, während automatische Gedächtnisprozesse unbeeinflusst bleiben. Dieser Befund spricht gegen die Gültigkeit der Kommensurabilitätsannahme. Die Konsequenzen des Befunds für Theorien des Gedächtnisses werden diskutiert.
Love Lamentation in Pop Songs: Music for Unhappy Lovers?
Authors: Knobloch Silvia , Weisbach Kerstin , Zillmann Dolf
Published: July 2004

Abstract. The investigation builds on and extends demonstrations in the U.S. that romantically disenchanted men and women are attracted to love-lamenting music. The current focus is on preferences of young German adults (n = 52). Ascertainment of respondents’ romantic situation was followed by a period in which they could listen to top-chart love songs, with lyrics expressing either celebration of happy love or lamentation of unrequited/lost love. Songs were presented via computer in a private listening situation. For a restricted period, respondents freely sampled from available songs. Exposure to sad love music was unobtrusively recorded. Amorously frustrated men exposed themselves longer to love-lamenting music than did more content men. Romantically disenchanted women similarly favored such music more than more hopeful women did. However, women in happy relationships exhibited an unexpectedly strong preference for music denouncing love. Thus, regarding men, findings fully replicate earlier observations; regarding women, the replication was only partial.
Selbstdarsteller 1DieZeitschrift für Medienpsychologieverwendet grundsätzlich die weibliche und männliche Form. Im Fall des Beitragstitels haben wir uns jedoch aus Gründen der besseren Lesbarkeit für diese Ausnahme entschieden. oder Menschen wie du und ich?
Authors: Machilek Franz , Schütz Astrid , Marcus Bernd
Published: July 2004

Zusammenfassung. Auf Basis einer mit der Zielsetzung der Repräsentativität gezogenen Stichprobe privater Homepages und einer web-basierten Befragung von N = 266 Homepagebesitzer/inne/n wird vor dem Hintergrund psychologischer Theorien der Selbstdarstellung ein Überblick über Ziele und Zielgruppen von Homepagebesitzer/inne/n gegeben. Hinsichtlich erfasster Persönlichkeitsvariablen werden die Besitzer/innen mit Vergleichsgruppen kontrastiert. In sozialer Hinsicht dienen Homepages nach Aussagen der Besitzer/innen weniger dazu, mit Identitäten zu spielen als sich authentisch zu zeigen - und unterscheiden sich dadurch von anderen Internetnutzungsformen wie MUDs. Ein Teil der Besitzer/innen richtet sich vor allem an Verwandte und Bekannte, andere eher an ein anonymes, unbekanntes Publikum. Entgegen landläufigen Vermutungen sind Homepagebesitzer/innen weder besonders extravertiert noch besonders narzisstisch. Im Vergleich zu anderen sind sie interessiert an Technik und relativ offen für neue Erfahrungen und eher introvertiert.
A Comparison of the Reliabilities of Four Types of Difference Scores for Five Cognitive Assessment Batteries
Authors: Caruso John C.
Published: July 2004

Summary: In recent years, studies have been conducted comparing the reliability of simple difference scores to differences computed via reliable component analysis (RCA). For the five cognitive assessment batteries examined here, RCA difference scores have been superior to simple difference scores in this regard. In the present study, the five cognitive assessment batteries are considered again, including a comparison of two alternative methods of difference score construction, the residualized and base-free difference methods, in order to determine if RCA outperforms the other methods as well. Results indicated that the RCA difference scores were more reliable in 68/70 comparisons between the four methods. When difference scores are a central part of test interpretation, clinicians should use the RCA scoring method because of the high reliability of the difference scores.
Relationships Among Social Anxiety Measures and Their Invariance1
Authors: Olivares José , García-López Luis Joaquín , Hidalgo María Dolores , Caballo Vicente
Published: July 2004

Summary: Social phobia is becoming increasingly recognized as an important disorder among adolescents. The body of research on assessment measures in adolescents with social phobia has grown considerably. Unfortunately, little is known about the relationship among these measures and its invariance across clinical and community samples. The objective of the present study is to examine this issue. Results show that all of these measures are invariant among samples and assess a single higher-order factor, labeled as “social anxiety,” although each measure appears to tap a specific symptom (cognitive, behavioral, and somatic). Further, results do support the Social Phobia and Anxiety Inventory (SPAI) and the Social Anxiety Scale for Adolescents (SAS-A) as first-line assessment measures for adolescents' social anxiety.
Deriving in situ phytoplankton absorption for bio‐optical productivity models in turbid waters
Authors: Oliver Matthew J. , Schofield Oscar , Bergmann Trisha , Glenn Scott , Orrico Cristina , Moline Mark
Published: July 2004

As part of Hyperspectral Coupled Ocean Dynamics Experiment, a high‐resolution hydrographic and bio‐optical data set was collected from two cabled profilers at the Long‐Term Ecosystem Observatory (LEO). Upwelling‐ and downwelling‐favorable winds and a buoyant plume from the Hudson River induced large changes in hydrographic and optical structure of the water column. An absorption inversion model estimated the relative abundance of phytoplankton, colored dissolved organic matter (CDOM) and detritus, as well as the spectral exponential slopes of CDOM and detritus from in situ WET Labs nine‐wavelength absorption/attenuation meter (ac‐9) absorption data. Derived optical weights were proportional to the parameter concentrations and allowed for their absorptions to be calculated. Spectrally weighted phytoplankton absorption was estimated using modeled spectral irradiances and the phytoplankton absorption spectra inverted from an ac‐9. Derived mean spectral absorption of phytoplankton was used in a bio‐optical model estimating photosynthetic rates. Measured radiocarbon uptake productivity rates extrapolated with water mass analysis and the bio‐optical modeled results agreed within 20%. This approach is impacted by variability in the maximum quantum yield (ϕmax) and the irradiance light‐saturation parameter (Ek(PAR)). An analysis of available data shows that ϕmax variability is relatively constrained in temperate waters. The variability of Ek(PAR) is greater in temperate waters, but based on a sensitivity analysis, has an overall smaller impact on water‐column‐integrated productivity rates because of the exponential decay of light. This inversion approach illustrates the utility of bio‐optical models in turbid coastal waters given the measurements of the bulk inherent optical properties.
Coastal ocean wind fields gauged against the performance of an ocean circulation model
Authors: He Ruoying , Liu Yonggang , Weisberg Robert H.
Published: July 2004

Atmosphere model‐derived flux fields are used to force coastal ocean models. Coarse resolution and incomplete boundary layer dynamics limit the accuracy of these forcing fields and hence the performance of the ocean models. We address this limitation for the west Florida shelf using optimal interpolation to blend winds measured in situ with winds produced by model analyses. By improving the coastal wind field we improve the fidelity between currents modeled and currents observed. Comparisons between momentum analyses performed independently from the model and the data demonstrate the fidelity to be of a correct dynamical basis. We conclude that the primary limitation to coastal ocean model performance lies with the boundary conditions.
Average characteristics of triggered and nontriggered substorms
Authors: Hsu Tung‐Shin , McPherron Robert L.
Published: July 2004

Magnetic field data from ground stations, geosynchronous orbit, and magnetotail are examined to study the response to substorm activity with and without apparent interplanetary magnetic field (IMF) perturbations. Global substorms are identified using a sudden, persistent decrease in the AL index. The onset of this global expansion is taken to be the time of the Pi2 burst nearest to the beginning of the AL decrease. IMF triggers were identified subjectively through visual scanning of the data. Both northward turnings of the IMF Bz and decreases in the amplitude of the By component were considered as possible triggers. Two different solar wind monitors were used in the investigation: IMP 8 in a circular orbit with a distance between ∼12 and ∼35 RE from the Earth‐Sun line and ISEE 2 in an elliptical orbit with a distance of only ∼5–10 RE from the Earth‐Sun line. The results of superposed epoch analysis show that the temporal response from ground stations, geosynchronous orbit, and magnetotail are nearly identical for triggered (with apparent IMF perturbation) and nontriggered (without apparent IMF perturbation) substorms. It is therefore concluded that the nontriggered substorms are not a different form of activity than triggered substorms. However, we demonstrate that the magnitude of the response is different for the two types of substorms. By every measure considered, triggered substorms are systematically larger than nontriggered substorms. We interpret the fact that nearly 40% of all substorms cannot be associated with an IMF trigger as evidence that substorms are caused by an internal instability. However, the fact that so many appear to be triggered suggests that this internal instability is susceptible to external perturbations by the IMF. The fact that triggered substorms are larger than nontriggered substorms is counterintuitive, and we have no explanation for the observation.
Policy, politics, and water management in the Guadalquivir River Basin, Spain
Authors: Bhat Anjali , Blomquist William
Published: July 2004

Among countries with river basin organizations to manage their water resources, Spain's experience is one of the longest. One of the first basin agencies established in Spain was for the Guadalquivir River in the south. A case study of that river basin and its management indicates how basin management is shaped by political economy factors such as the historical path of the agency's evolution, the basin agency's relationships with central government and with regional or local governments, the patterns of water user representation within the agency, and developments in water law and policy external to the basin agency. The case raises questions about whether and how integrated water resources management at the river basin scale is implemented, even in locations where basin agencies already exist. It also suggests that the politics of management at the river basin level will affect the implementation of national water policies intended to promote integrated management.
In situ production of chromophoric dissolved organic matter in coastal environments
Authors: Yamashita Youhei , Tanoue Eiichiro
Published: July 2004

The horizontal and vertical distribution of marine humic‐like fluorophore, namely, chromophoric dissolved organic matter (CDOM) fluorescence, was surveyed in Ise Bay, Japan. The distribution patterns of salinity and marine humic‐like fluorescence intensity suggested that riverine humic‐like fluorophore conservatively distributed along with fresh‐sea water mixing in surface water at Ise Bay. However, analysis of mixing behavior of riverine CDOM implied that the 25.1 ± 10.6% in average of bulk marine humic‐like fluorescence intensity of Ise Bay surface waters was derived not from a terrestrial origin but an in situ production. A degradation experiment using natural plankton demonstrated the rapid production of marine humic‐like fluorophore within a day. The results consistently suggested that in situ production of marine humic‐like fluorophore plays an important role in the dynamics of CDOM in coastal environments.
A high resolution transect of dissolved barium in the Southern Ocean
Authors: Jacquet S. H. M. , Dehairs F. , Rintoul S.
Published: July 2004

The dissolved Barium (Bad) distribution in the whole water column was examined along the WOCE SR3 line in the Southern Ocean (Australian sector, late winter‐spring 2001). The high sampling resolution offered an excellent opportunity to relate the Bad distribution to frontal structures and the water masses. Such a high resolution was not achieved in previous Southern Ocean studies and showed the tight overprinting of the frontal zones by Bad gradients. Hydrodynamic control on Bad is evident in the case of Antarctic Bottom Water formation, westward flow of Tasman Sea waters and return flow of an eddy of the SubAntarctic Front. However biogeochemical processes are also acting, as witnessed by enhanced Bad contents in deep waters of the SubAntarctic Front zone and by a local mesopelagic minimum in the Inter Polar Front Zone. These features are respectively ascribed to the dissolution of Ba‐rich phases and Ba transfer from solution to particles.
Assessment of the SAGE II version 6.2 water vapor data set through intercomparison with ATMOS/ATLAS‐3 measurements
Authors: Chiou Er‐Woon , Thomason Larry W. , Burton Sharon P. , Michelsen Hope A.
Published: July 2004

Based on the intercomparisons with ATMOS/ATLAS‐3 measurements, the SAGE II (Stratospheric Aerosol and Gas Experiment II) version 6.2 water vapor profiles exhibit significant improvements over earlier versions of data products. A previously reported SAGE II dry bias in the lower stratosphere relative to ATMOS version 3 data set has been effectively eliminated. In the new version, the agreement between SAGE II and ATMOS is generally within 15% with no systematic biases throughout the entire altitude range of 12 km to 40 km. The only exception is the situation for which 1020‐nm aerosol extinctions exceed the recommended upper limit of 3 × 10−4 km−1. Based on the comparisons, the reported uncertainties for SAGE II water vapor mixing ratios appear to be over‐estimated by a factor of 2 to 3 for the lower stratosphere.
Periodic magnetospheric substorms during fluctuating interplanetary magnetic field Bz
Authors: Huang Chao‐Song , Le Guan , Reeves Geoff D.
Published: July 2004

We study the possible role played by sudden changes in the solar wind in triggering substorm onsets. We show that periodic substorms can occur when the IMF Bz is small and fluctuating between southward and northward. The period of the substorms during the fluctuating IMF is ∼3 hours, nearly the same as that during strongly and continuously southward IMF. We also show that large sudden changes in the solar wind do not necessarily trigger substorm onsets. For example, a northward IMF turning with a change of 31 nT in the IMF Bz after 1.2 hours of strongly southward IMF (between −12 and −18 nT) did not cause a substorm onset. The observations show that the period of substorms is not controlled either directly by variations in the solar wind or indirectly by the energy transferred to the magnetosphere from the solar wind. We suggest that a sudden change in the solar wind can trigger a substorm onset if and only if the magnetosphere has reached a state conducive to the generation of substorms. Substorms will occur every ∼3 hours, no matter whether the IMF is continuously southward or fluctuating between southward and northward.
The large‐scale dynamics of the mesosphere–lower thermosphere during the Southern Hemisphere stratospheric warming of 2002
Authors: Dowdy Andrew J. , Vincent Robert A. , Murphy Damian J. , Tsutsumi Masaki , Riggin Dennis M. , Jarvis Martin J.
Published: July 2004

An unprecedented major stratospheric warming occurred in the Antarctic winter of 2002. We present measurements of winds in the mesosphere‐lower thermosphere (MLT) made with MF radars located at Davis (69°S, 78°E), Syowa (69°S, 40°E) and Rothera (68°S, 68°W). The mesospheric wind field in 2002 was found to be considerably different to other years due to increased planetary wave activity throughout the winter. Zonal winds were weaker than usual during the 2002 winter and also during the transition to the summer circulation. The MLT zonal winds showed a reversal about one week earlier than the stratospheric reversal associated with the warming. Meridional winds showed oscillations consistent with the presence of traveling wave‐1 planetary waves with periods ∼14 days. The results are compared with similar mesospheric observations made during northern hemisphere stratospheric warmings. Some similarities between hemispheres were found, notably that the reversal in the mesospheric winds precedes the warming events.
The deformation field of the August 2003 eruption at Piton de la Fournaise, Reunion Island, mapped by ASAR interferometry
Authors: Froger J.‐L. , Fukushima Y. , Briole P. , Staudacher T. , Souriot T. , Villeneuve N.
Published: July 2004

Three independent ASAR interferograms spanning the August 2003 Piton de la Fournaise eruption, reveal a 3 by 3 km asymmetric pattern of range changes centred on the Dolomieu crater northern flank. It corresponds to 30 cm of displacement towards the satellite east of the eruptive fissures and 7 cm away from the satellite west of the fissures. Displacements are caused by dyke emplacement below fissures. We model the deformation using a 3D mixed boundary element method for elastic media. This consists of a dyke defined by six geometric parameters and an overpressure gradient. A neighbourhood algorithm was applied to explore this 7 dimensional parameter space. The best‐fit model is a 57° eastward dipping dyke with a base lying around 1520 m a.s.l. The model provides new evidence of the dyke intrusion – related seaward displacements of the volcano eastern flank.
Equatorial stratospheric response to variations in deterministic and stochastic gravity wave parameterizations
Authors: Piani C. , Norton W. A. , Stainforth D. A.
Published: July 2004

The sensitivity of the equatorial stratospheric climate to variations in the gravity wave parameterization is examined in the Unified Model. Particular emphasis is placed on the response of the annual cycle and quasi‐biennial oscillation of zonal winds. Two classes of variations are considered. The first consists of variations in the source strength of the classic deterministic formulation of a Doppler‐spread Doppler‐shifted gravity wave scheme. The second consists of variations in the probability density function of the source strength parameter in a stochastic formulation of the same scheme. The effects on stratospheric climate of variations in the source strength of a deterministic scheme can be predicted from theory. In such a scheme, when choosing the best possible value for the source strength, a trade‐off between a proper representation of the quasi‐biennial oscillation and the annual cycle is inevitable. Implementation of a stochastic source strength in the resident gravity wave scheme is justified by the need to better represent the intermittent nature of the convective generation of gravity waves. The most striking effect of the stochastic parameterization is the stabilization of the quasi‐biennial oscillation in multidecadal simulations. We suggest that this is due to the ability of the stochastic gravity wave parameterization to deposit a larger portion of gravity wave drag in the middle stratosphere.
Irbesartan inhibits human T‐lymphocyte activation through downregulation of activator protein‐1
Authors: Cheng Shu‐Meng , Yang Shih‐Ping , Ho Ling‐Jun , Tsao Tien‐Ping , Chang Deh‐Ming , Lai Jenn‐Haung
Published: July 2004

Irbesartan is a promising antihypertensive drug with beneficial effects on atherosclerotic processes. In the progression of atherosclerosis, human T‐lymphocytes play an important role, but it is not yet known how irbesartan modulates human T‐lymphocytes activation. To gain insight into the mechanisms by which irbesartan acts, we investigated its effects on human T‐lymphocytes.

Primary human T‐lymphocytes were isolated from whole blood. Cytokines were determined by ELISA. Activator protein‐1 (AP‐1) and related protein activities were determined by electrophoretic mobility shift assays, kinase assays, Western blotting and transfection assays.

Irbesartan inhibited the production of both tumor necrosis factor‐alpha and interferon‐gamma by activated T‐cells, especially at therapeutic concentrations. Further investigation at the molecular level indicated that the inhibition of activated human T‐lymphocytes specifically correlated with the downregulation of AP‐1 DNA‐binding activity. In the Jurkat T‐cell line, irbesartan also inhibited AP‐1 transcriptional activity. Finally, we revealed that irbesartan is unique in its ability to inhibit the activation of both c‐Jun NH2‐terminal protein kinase and p38 MAPK.

Our studies show that irbesartan may modulate inflammation‐based atherosclerotic diseases through a cell‐mediated mechanism involving suppression of human T‐lymphocytes activation via downregulation of AP‐1 activity.

British Journal of Pharmacology (2004) 142, 933–942. doi:10.1038/sj.bjp.0705785
Methylene ATP analogs as modulators of extracellular ATP metabolism and accumulation
Authors: Joseph Sheldon M , Pifer Matthew A , Przybylski Ronald J , Dubyak George R
Published: July 2004

Transient accumulation of extracellular ATP reflects both release of ATP from intracellular stores and altered rates of ATP metabolism by ecto‐enzymes. Ecto‐nucleoside triphosphate diphosphohydrolases (eNTPDases) and ecto‐nucleotide pyrophosphatases (eNPPs) degrade ATP, while ecto‐nucleotide diphosphokinases (eNDPKs) synthesize ATP from ambient ADP.

Although the methylene ATP analogs βγ‐meATP and αβ‐meATP are widely used as metabolically stable tools for the analysis of purinergic signaling, their specific effects on eNTPDase, eNPP, and eNDPK activities have not been defined. This study compared the actions of these analogs on extracellular ATP metabolism by human 1321N1 astrocytes, rat PC12 pheochomocytoma cells, and rat C6 glioma cells.

Both analogs significantly reduced clearance of extracellular ATP by 1321N1 cells that express both eNTPDases and eNPPs, as well as by C6 cells that exclusively express eNPPs. In contrast, both analogs were much less efficacious in inhibiting ATP clearance by PC12 cells that predominantly express eNTPDases. βγ‐meATP, but not αβ‐meATP, was effectively hydrolyzed by the 1321N1 and C6 cells; PC12 cells did not significantly degrade this analog.

αβ‐meATP, but not βγ‐meATP, acted as a substrate for purified yeast NDPK to generate ATP via trans‐phosphorylation of ADP. αβ‐meATP also acted as substrate for the eNDPK activities expressed by 1321N1, PC12, and C6 cells and thereby induced extracellular ATP accumulation in the presence of ambient or exogenously added ADP.

These results indicate that methylene ATP analogs exert complex and cell‐specific effects on extracellular ATP metabolism that can significantly modify interpretation of studies that use these reagents as probes of purinergic signal transduction in intact tissues.

British Journal of Pharmacology (2004) 142, 1002–1014. doi:10.1038/sj.bjp.0705865
Chelerythrine and other benzophenanthridine alkaloids block the human P2X7 receptor
Authors: Shemon Anne N , Sluyter Ronald , Conigrave Arthur D , Wiley James S
Published: July 2004

Extracellular ATP can activate a cation‐selective channel/pore on human B‐lymphocytes, known as the P2X7 receptor. Activation of this receptor is linked to PLD stimulation. We have used ATP‐induced 86Rb+ (K+) efflux to examine the effect of benzophenanthridine alkaloids on P2X7 channel/pore function in human B‐lymphocytes.

Both ATP and the nucleotide analogue 2′‐3′‐O‐(4‐benzoylbenzoyl)‐ATP (BzATP) induced an 86Rb+ efflux, which was completely inhibited by the isoquinoline derivative 1‐(N,O‐bis[5‐isoquinolinesulphonyl]‐N‐methyl‐L‐tyrosyl)‐4‐phenylpiperazine (KN‐62), a potent P2X7 receptor antagonist.

The benzophenanthridine alkaloid chelerythrine, a potent PKC inhibitor, inhibited the ATP‐induced 86Rb+ efflux by 73.4±3.5% and with an IC50 of 5.6±2.3 μM. Similarly, other members of this family of compounds, sanguinarine and berberine, blocked the ATP‐induced 86Rb+ efflux by 58.8±4.8 and 61.1±8.0%, respectively.

Concentration–effect curves to ATP estimated an EC50 value of 78 μM and in the presence of 5 and 10 μM chelerythrine this increased slightly to 110 and 150 μM, respectively, which fits a noncompetitive inhibitor profile for chelerythrine.

Chelerythrine at 10 μM was effective at inhibiting the ATP‐induced PLD stimulation in B‐lymphocytes by 94.2±21.9% and the phorbol 12‐myristate 13‐acetate‐induced PLD stimulation by 68.2±7.4%.

This study demonstrates that chelerythrine in addition to PKC inhibition has a noncompetitive inhibitory action on the P2X7 receptor itself.

British Journal of Pharmacology (2004) 142, 1015–1019. doi:10.1038/sj.bjp.0705868
Junctional and nonjunctional effects of heptanol and glycyrrhetinic acid derivates in rat mesenteric small arteries
Authors: Matchkov Vladimir V , Rahman Awahan , Peng Hongli , Nilsson Holger , Aalkjær Christian
Published: July 2004

Heptanol, 18α‐glycyrrhetinic acid (18αGA) and 18β‐glycyrrhetinic acid (18βGA) are known blockers of gap junctions, and are often used in vascular studies. However, actions unrelated to gap junction block have been repeatedly suggested in the literature for these compounds. We report here the findings from a comprehensive study of these compounds in the arterial wall.

Rat isolated mesenteric small arteries were studied with respect to isometric tension (myography), [Ca2+]i (Ca2+‐sensitive dyes), membrane potential and – as a measure of intercellular coupling – input resistance (sharp intracellular glass electrodes). Also, membrane currents (patch‐clamp) were measured in isolated smooth muscle cells (SMCs). Confocal imaging was used for visualisation of [Ca2+]i events in single SMCs in the arterial wall.

Heptanol (150 μM) activated potassium currents, hyperpolarised the membrane, inhibited the Ca2+ current, and reduced [Ca2+]i and tension, but had little effect on input resistance. Only at concentrations above 200 μM did heptanol elevate input resistance, desynchronise SMCs and abolish vasomotion.

18βGA (30 μM) not only increased input resistance and desynchronised SMCs but also had nonjunctional effects on membrane currents. 18αGA (100 μM) had no significant effects on tension, [Ca2+]i, total membrane current and synchronisation in vascular smooth muscle.

We conclude that in mesenteric small arteries, heptanol and 18βGA have important nonjunctional effects at concentrations where they have little or no effect on intercellular communication. Thus, the effects of heptanol and 18βGA on vascular function cannot be interpreted as being caused only by effects on gap junctions. 18αGA apparently does not block communication between SMCs in these arteries, although an effect on myoendothelial gap junctions cannot be excluded.

British Journal of Pharmacology (2004) 142, 961–972. doi:10.1038/sj.bjp.0705870
Hepatocytes from α1B‐adrenoceptor knockout mice reveal compensatory adrenoceptor subtype substitution
Authors: Deighan Clare , Woollhead Alison M , Colston Janet F , McGrath John C
Published: July 2004

α1‐Adrenoceptors (ARs) play an important functional role in the liver; yet little is known about their cellular location. We identified the subtypes present in wild‐type (WT) and α1B‐AR knockout (KO) mice livers at 3 and 4 months of age, and investigated their distribution in hepatocytes.

The fluorescent α1‐AR antagonist quinazolinyl piperazine borate‐dipyrromethene (QAPB) was used to visualise hepatic α1‐ARs and radioligand binding with [3H]‐prazosin was used to quantify the α1‐AR population.

QAPB and [3H]‐prazosin bound specifically to hepatic α1‐ARs with nanomolar affinity. The cellular distribution of α1‐ARs was similar in WT and α1B‐AR KO hepatocytes; QAPB binding was distributed diffusely throughout the cell with no binding evident on the plasma membrane. Radioligand binding produced Bmax values as follows: 3‐month WT – 76±3.3 fmol mg−1; 4‐month WT – 50±3.1 fmol mg−1; 3‐month α1B‐AR KO – 7.4±0.73 fmol mg−1; 4‐month α1B‐AR KO – 30±2.0 fmol mg−1.

In 3‐ and 4‐month WT liver, all antagonists acted competitively. RS100329 (α1A‐selective) and BMY7378 (α1D‐selective) bound with low affinities, indicating the presence of α1B‐ARs. In 4‐month α1B‐AR KO liver prazosin produced a biphasic curve, whereas RS100329 and BMY7378 produced monophasic curves of high and low affinity, respectively, indicating the presence of α1A‐ARs.

In conclusion, we have made the novel observation that α1‐ARs can compensate for one another in the absence of the endogenously expressed receptor; yet there appears to be no subtype‐specific subcellular location of α1‐ARs; the WT livers express α1B‐ARs, while α1B‐AR KO livers express α1A‐ARs. This study provides new insights into both hepatocyte and α1‐AR biology.

British Journal of Pharmacology (2004) 142, 1031–1037. doi:10.1038/sj.bjp.0705872
Shp1 and Ubx2 are adaptors of Cdc48 involved in ubiquitin‐dependent protein degradation
Authors: Schuberth Christian , Richly Holger , Rumpf Sebastian , Buchberger Alexander
Published: July 2004

Known activities of the ubiquitin‐selective AAA ATPase Cdc48 (p97) require one of the mutually exclusive cofactors Ufd1/Npl4 and Shp1 (p47). Whereas Ufd1/Npl4 recruits Cdc48 to ubiquitylated proteins destined for degradation by the 26S proteasome, the UBX domain protein p47 has so far been linked exclusively to nondegradative Cdc48 functions in membrane fusion processes. Here, we show that all seven UBX domain proteins of Saccharomyces cerevisiae bind to Cdc48, thus constituting an entire new family of Cdc48 cofactors. The two major yeast UBX domain proteins, Shp1 and Ubx2, possess a ubiquitin‐binding UBA domain and interact with ubiquitylated proteins in vivo. Δshp1 and Δubx2 strains display defects in the degradation of a ubiquitylated model substrate, are sensitive to various stress conditions and are genetically linked to the 26S proteasome. Our data suggest that Shp1 and Ubx2 are adaptors for Cdc48‐dependent protein degradation through the ubiquitin/proteasome pathway.
Dermatofibrosarcoma protuberans – An Update
Authors: Breuninger Helmut , Sebastian Günther , Garbe Claus
Published: July 2004

Dermatofibrosarcoma protuberans (DFSP) is a rare fibroblastic skin tumor of intermediate malignancy. Its pathogenesis has not yet been fully clarified. Recent basic genetic research has shown chromosomal translocations, generally termed “ring chromosomes”, in DFSP. These arise from a fusion of chromosome regions 17q22 and 22q13, the gene loci which code the alpha chain of type I collagen.

The diagnosis is made histologically. Differentiation from atypical dermatofibroma and dermatomyofibroma, as well as from malignant fibrous histiocytoma, whose prognosis is usually much less favorable, can be improved by immunostaining for CD 34 and Factor XIIIa. The extent of the tumors can be estimated by CT and more precisely with MRI. All these techniques fail to detect the fine tumor fascicles extending into the adjacent connective tissue and fat.

Surgery is the therapy of choice for DFSP. The locally infiltrative growth pattern features clinically inapparent extensions which often extend for long distances in a horizontal direction. These tumor extensions are best detected by uninterrupted histological check of all margins, including the base (3‐D‐histology), with paraffin sections. Re‐excision of tumor‐positive areas until tumor‐free margins are obtained (“histographic surgery”) insures a high cure rate (97 %) while preserving normal tissue.
What's in a View?
Authors: Bourassa Steven C , Hoesli Martin , Sun Jian
Published: July 2004

The impact of views on property values has not been the specific focus of as much research as has the impact of other externalities on property values. When the impact of views is assessed, it is usually done by adding a single dummy variable to a hedonic regression equation. This paper provides a detailed literature review as well as an empirical analysis of the impact of a view on residential property values with a very rich database of nearly 5000 sales in Auckland, New Zealand. Several dimensions of a view are analyzed: type of view, scope of view, distance to coast, appearance of immediately surrounding improvements, average quality of landscaping in the neighborhood, and average quality of structures in the neighborhood. It is found that wide views of water add an average of 59% to the value of a waterfront property but that this effect diminishes quite rapidly as the distance from the coast increases. Attractive buildings in the neighborhood of a property on average add 37% to value relative to properties in neighborhoods with only average-quality structures. Particularly attractive improvements in the immediate surroundings of a property add another 27% to value on average. In contrast, properties in neighborhoods with only poor-quality landscaping on average experience a – 51% impact on price. Our results lead to the conclusion that aesthetic externalities are multidimensional and can have a substantial impact on residential property values.