bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrogenation of fatty acid methyl esters to fatty alcohols at supercritical conditions
Authors: Hark Sander van den , Härröd Magnus , Møller Poul
Published: June 2007

Extremely rapid hydrogenation of fatty acid methyl esters (FAME) to fatty alcohols (FOH) occurs when the reaction is conducted in a substantially homogeneous supercritical phase, using propane as a solvent, over a solid catalyst. At these conditions, the limitations of hydrogen transport are eliminated. At temperatures above 240°C, complete conversion of the starting material was reached at residence times of 2 to 3 s, which is several orders of magnitude shorter than reported in the literature. Furthermore, formation of by‐products, i.e., hydrocarbons, could be prevented by choosing the right process settings. Hydrogen concentration turned out to be the key parameter for achieving the above two goals. As a result of the supercritical conditions, we could control the hydrogen concentration at the catalyst surface independently of the other process parameters. When methylated rapeseed oil was used as a substrate, the hydrogenation catalyst was deactivated rapidly. However, by using methylated sunflower oil, a catalyst life similar to that obtained in industrial processes was achieved. Our results showed that the hydrogenation of FAME to FOH at supercritical conditions is a much more efficient method than any other published process.
Effect of xanthan gum on enhancing the foaming properties of whey protein isolate
Authors: Mott C. L. , Hettiarachchy N. S. , Qi M.
Published: June 2007

The foaming properties of whey protein isolate (WPI) in the presence of xanthan gum (XG) were investigated. XG dispersion did not exhibit any foaming properties. The optimal foaming overrun (FO), or the amount of air incorporated into the dispersion, was obtained from the dispersion of 5% WPI and 0.05% XG at 949%. This WPI‐XG dispersion had a significantly higher overrun than that of WPI (868%) or egg white (879%) (P<0.05). Optimal foam stability (FS) of 216 min was obtained at 5% WPI and 0.2% XG; however, the overrun was reduced slightly (844%). XG increased stability to 15 times that of WPI alone. The overrun of 5% WPI plus 0.05% XG was further increased to 1343% when 1 M NaCl was added (P<0.05). However, FS (51 min) was significantly reduced. A significant increase in the FO of 5% WPI plus 0.05% XG (1081%) was observed when pH was adjusted to 5.0 with no significant change in FS (56 min) (P<0.05). The FO (1457%) was significantly increased (P<0.05) when the WPI‐XG was heat treated (55°C for 5 min). WPI‐XG dispersions at acidic pH and temperatures below 85°C have a variety of potential applications in products such as protein beverages, angel food cake, and unique infant formulas.
Ammonia channeling in bacterial glucosamine‐6‐phosphate synthase (Glms): Molecular dynamics simulations and kinetic studies of protein mutants
Authors: Floquet Nicolas , Mouilleron Stéphane , Daher Rasha , Maigret Bernard , Badet Bernard , Badet-Denisot Marie-Ange
Published: June 2007

Ammonia transfer from the glutamine site to the fructose‐6P site of bacterial glucosamine‐6‐phosphate synthase was studied by molecular dynamics simulations. The studies suggest a key role for Trp74, in the sealing of the hydrophobic channel connecting the two binding sites, as well as for the two Ala602 and Val605 residues, which form a narrow passage whose opening/closing constitutes an essential event in ammonia transfer. Kinetic analyses of the corresponding protein mutants confirmed our predictions. The efficiency of ammonia transfer which was close to zero in the W74A mutant was partially restored by increasing the size of the corresponding side‐chain; the simulations performed on the W74A mutant suggested the formation of a hole in the channel. In the case of A602L and V605L mutants, the efficiency of ammonia transfer decreased to ∼50% of the value of the native protein. None of the mutants were, however, able to use exogenous ammonia as a substrate.
Radiocarpal Arthrodesis in the Treatment of the Rheumatoid Wrist. A Prospective Midterm Follow-up
Authors: HONKANEN P. B. , MÄKELÄ S. , KONTTINEN Y. T. , LEHTO M. U. K.
Published: June 2007

This prospective study was performed to evaluate the clinical and radiological results of radiocarpal joint arthrodesis in the treatment of unstable Simmen group III and Larsen grade II or III rheumatoid wrists. Radiolunate arthrodesis was performed in 16 wrists and radioscapholunate arthrodesis in 7 wrists in 20 patients. When they were evaluated at a mean of 5.8 (range 3.5–9.8) years later, flexion was 29° and extension 34°, representing 67% and 92% of the preoperative values, respectively. Patient satisfaction was excellent, or good, for 20 wrists and satisfactory for 1 wrist. In two patients with poor satisfaction, arthritis progressed to the midcarpal joint and necessitated total arthrodesis of the wrist. Radiolunate joint arthrodesis, with inclusion of the scaphoid in the fusion if necessary, is a useful operation in the treatment of this degree of wrist disease as it produces a functional and pain-free wrist at the same time as preserving much of the mobility and bone stock.
Making Sense of Political Toleration
Authors: JONES PETER
Published: June 2007

This article argues that, in contemporary political circumstances, we should think of political toleration not as toleration that a government extends to those it rules but as a political ideal that governments can uphold and promote. We should substitute a conception of the tolerant society or the tolerant political order for that of the tolerant ruler. Toleration so conceived is consistent with the idea of a neutral state, although it need not entail a commitment to political neutrality. However, if we are to make sense of the idea of a tolerant society and, in particular, of the assumption that one political arrangement can be more tolerant than another, we need to place limits on what can count as toleration and intolerance. I use a distinction between agents, observers and patients to argue that point. I also argue that the presence of compossible options is a precondition of political toleration so that, if an issue requires a choice between incompossible options, it should not be conceived as an issue of toleration at all. The general message of the article is that, while we should reject claims that toleration has become obsolete as a political ideal, we need to revise our thinking on what constitutes political toleration if we are to apply that idea to liberal democratic arrangements ideally conceived.
Vetoing Co-operation: The Impact of Veto Players on Preferential Trading Arrangements
Authors: MANSFIELD EDWARD D. , MILNER HELEN V. , PEVEHOUSE JON C.
Published: June 2007

Since the Second World War, preferential trading arrangements (PTAs) have become increasingly pervasive features of the international economic system. A great deal of research has addressed the economic consequences of these arrangements, but far less effort has been made to identify the political factors leading states to enter them. In this article, the domestic political factors affecting whether countries enter PTAs are investigated, placing particular emphasis on the number of veto players within a state. It is argued that the probability of forming a PTA declines as the number of such players rises. The results, covering 194 countries from 1950 to 1999, strongly support this argument. Holding various political and economic factors constant, increasing the number of veto players within a country significantly reduces the probability of signing a PTA.
Reconsidering the Linkage between Public Assistance and Public Opinion in the American Welfare State
Authors: SCHNEIDER SAUNDRA K. , JACOBY WILLIAM G.
Published: June 2007

In an article published in this Journal, we have examined whether American welfare recipients possess beliefs and attitudes that differ from mainstream public opinion. Although our findings cast doubt on the existence of a widespread ‘culture of dependence’, we do show that programme beneficiaries exhibit self-interested support for government policies that provide assistance to needy segments of the population. However, our analysis – like most others on this topic – assumes that welfare participation affects opinions and not vice versa. This is problematic because there are theoretical reasons to believe that influences flow in the opposite direction, as well. Therefore, some important questions remain to be answered: is it really the case that welfare participation, itself, shapes the outlook of programme beneficiaries? Or do political attitudes affect reliance on public assistance in the first place?

In this Research Note, we examine the underlying structure of the relationship between welfare participation and attitudes towards government activity. Our analysis uses the 1992 Center for Political Studies (CPS) National Election Study, the same dataset employed in the earlier article. But, we test a statistical model that allows for reciprocal influences between welfare and public opinion. The empirical results reinforce the earlier conclusion that welfare participation has an impact on mass attitudes. Conversely, political attitudes have no effect on whether citizens use public aid. Mirroring our earlier work, we find that people who rely on governmental assistance take rational, self-interested positions on the public policy issues which operate to their own direct benefit.
The Influence of Response Lines on Response Behavior in the Context of Open-Question Formats
Authors: Spörrle Matthias , Gerber-Braun Beatrice , Försterling Friedrich
Published: June 2007

Research on questionnaire design has shown that respondents take a questionnaire’s formal aspects into account when formulating their answers to closed-ended questions (e.g., rating scales, multiple-choice questions). As similar research on open-response questions has been scanty, the objective of this study was to investigate the systematic influence of formal features of open-response questions on response behavior. Specifically, in two studies using different topics of opinion, we examined how the responses to open-ended questions vary as a function of the number of lines provided for the response. In both studies, increasing the number of response lines resulted in a constant increase in response length (quantity). It also resulted in an increase in the number of arguments in a response (quality) when only a few response lines were provided, which plateaued when many lines were provided. Overall, these results demonstrate that formal features of open-response questions implicitly communicate the expected quantity and quality of the answer.
The Effect of Reward Interdependence on Cooperation and Information-Sharing Intentions
Authors: Moser Karin S. , Wodzicki Katrin
Published: June 2007

Incentives are central to the reinforcement of behavior. In the context of group work, it is important to distinguish between individual and collective incentives as rewards. High reward interdependence should constitute an incentive for cooperation among group members (e.g., collective vs. individual financial rewards), but experimental studies provide no support for this assumption, whereas some field studies found an increase in information exchange and team productivity. In the two experimental studies presented here (N1 = 46, N2 = 28), high reward interdependence resulted in a higher willingness to share information with and to help other group members, stronger responses to the poor quality of others’ work, higher preference for a group layout, and less withdrawal as a response to the reluctant commitment of others. The findings suggest that high reward interdependence can indeed act as an incentive for cooperative behavior and information sharing in an experimental setting as well.
Assessing Empathy in Prisoners - A Shortened Version of the Interpersonal Reactivity Index
Authors: Lauterbach Oliver , Hosser Daniela
Published: June 2007

Davis’ Interpersonal Reactivity Index (IRI) was used to assess empathy in a sample of 839 male prisoners aged 15-28. Because recent studies have questioned the usability of the IRI with offenders, psychometric properties of the instrument were analyzed while taking intelligence and verbal skills into consideration as potential influencing factors. Results showed that offenders with a lower IQ and lower verbal skills had difficulties with negatively worded items. After negatively worded items had been eliminated, the component structure of the IRI was replicated. Reliabilities of the shortened version were sufficient and differential validity was found. The fantasy, perspective taking, and empathic concern subscales differentiated between violent and nonviolent offenders. Furthermore, in a logistic regression, the perspective taking subscale contributed significantly to the prediction of future violent offending within 24 months after release.
SSPS - Ein Fragebogen zur Erfassung der kognitiven Komponente von Redeangst
Authors: Gerlach Alexander L. , Heinrichs Nina , Bandl Claudia , Zimmermann Tanja
Published: June 2007

Zusammenfassung. Theoretischer Hintergrund: Angst vor öffentlichem Reden ist ein besonders wichtiger Aspekt der Sozialen Angststörung. Mit der deutschen Version der “Self Statements During Public Speaking Scale (SSPS) wird ein 10-Item Fragebogen zur Erfassung positiver und negativer Selbstaussagen in öffentlichen Sprechsituationen vorgestellt. Fragestellung: Es wurde die Faktorenstruktur, Reliabilität sowie Validität der deutschen Übersetzung der Skala untersucht. Methoden: Eine studentische deutsche Stichprobe von insgesamt 385 Personen sowie eine kleine klinische Stichprobe aus Panikpatienten und Sozialphobikern füllte die SSPS sowie eine Reihe weiterer Fragebögen zur Erfassung von Psychopathologie aus. Die Faktorenstruktur des englischen Instruments wurde mit Hilfe einer konfirmatorischen Faktorenanalyse überprüft. Ergebnisse: Die Faktorenstruktur der amerikanischen Version konnte weitestgehend bestätigt werden. Die internen Konsistenzen zeigten befriedigende bis gute Werte in der studentischen Stichprobe. Selbstberichtete Redeängstlichkeit konnte mit der Skala gut vorhergesagt werden. Schlussfolgerung: Mit der SSPS liegt folglich eine kurze, reliable und valide deutschsprachige Skala zur Erfassung des kognitiven Anteils von Redeangst vor.
Welche Auswirkungen hat Ehe- und Paarberatung auf die Sexualität und die sexuelle Zufriedenheit?
Authors: Kröger Christine , Hahlweg Kurt , Klann Notker
Published: June 2007

Zusammenfassung. Theoretischer Hintergrund: Die meisten Studien zur Wirksamkeit von Paartherapie basieren auf Veränderungen der globalen Partnerschaftszufriedenheit und informieren nicht darüber, welche Auswirkungen paartherapeutische Interventionen im Bereich der Sexualität haben. Fragestellung: Im Rahmen des vorliegenden Beitrags wird untersucht, welche Effekte Ehe- und Paarberatung auf die Sexualität und die sexuelle Zufriedenheit hat. Methode: Im Rahmen einer prospektiven Feldstudie wurde 293 Paaren, die sich auf Grund von Partnerschaftsproblemen an eine Eheberatungsstelle gewendet haben, zu Beratungsbeginn und -ende die Subskala “Sexuelle Zufriedenheit“ des Fragebogens zur Einschätzung von Partnerschaft und Familie (EPF) vorgelegt. Ergebnisse: Ehe- und Paarberatung bewirkt zumindest bei denjenigen Paaren, die in der Sexualität besonders belastet sind, eine signifikante Verbesserung der allgemeinen sexuellen Zufriedenheit. Schlussfolgerung: Paarberatung kann möglicherweise dazu beitragen, eine Chronifizierung sexueller Schwierigkeiten abzufangen.
Kritische Überprüfung der Faktorenstruktur und Konstruktvalidität des Whiteley-Index - einem etablierten Screening-Instrument zur Erfassung von Hypochondrie
Authors: Schwarz Daniela , Witthöft Michael , Bailer Josef
Published: June 2007

Zusammenfassung. Theoretischer Hintergrund: Der Whiteley-Index (WI) ist ein international etabliertes Screening-Instrument zur Erfassung von Hypochondrie. Trotz großer Verbreitung herrscht Unklarheit über die faktorielle Struktur und Konstruktvalidität. Fragestellung: Kritische Überprüfung der Faktorenstruktur des WI. Methode: An einer umfangreichen Stichprobe von Studierenden (N = 1302) wurden sechs konkurrierende Modelle zur Faktorenstruktur des WI mittels konfirmatorischer Faktorenanalyse überprüft. Ergebnisse: Eine gute Modellpassung erzielte lediglich eine 2-faktorielle Lösung mit radikal reduzierter Itemanzahl. Auf Grund explorativer Analysen wurde ein alternatives 2-faktorielles Modell mit 10 Items realisiert und an einer zweiten Stichprobe (N = 804) konfirmatorisch repliziert. Zusammenhänge mit konvergenten und diskriminanten Außenkriterien belegen insbesondere die Konstruktvalidität des ersten Faktors “Krankheitsangst“, während der zweite Faktor “Krankheitsüberzeugung und Beschwerden“ abbildet. Schlussfolgerungen: Implikationen der Ergebnisse für die Anwendung des WI werden diskutiert.
Die Diskriminationsleistung des Beck-Depressions-Inventars (BDI) hinsichtlich depressiver Störungen bei Patienten mit einer körperlichen Erkrankung
Authors: Barth Jürgen , Paul Juliane , Klesse Christian , Bengel Jürgen , Härter Martin
Published: June 2007

Zusammenfassung. Hintergrund: Depressive Störungen und koronare Herzkrankheit (KHK) treten häufig gemeinsam auf. Zur Erkennung depressiver Störungen bieten sich Screeningfragebögen an. Fragestellung: Die vorliegende Studie untersuchte die Diskriminationsleistung des Beck-Depressions-Inventars (BDI) und von vier theoretisch abgeleiteten BDI-Subskalen bei der Erkennung depressiver Störungen und depressiver Anpassungsstörungen bei KHK-Patienten. Methodik: 153 KHK-Patienten, die sich in der Hospital Anxiety and Depression Scale (HADS) als psychisch belastet beschrieben haben, wurden durch ein klinisches Interview diagnostiziert und füllten das BDI aus. Die Daten wurden in Receiver-Operating-Characteristics-Analysen ausgewertet. Ergebnisse: Bei 60 Patienten wurde eine affektive Störung bzw. eine depressive Anpassungsstörung diagnostiziert. In Reliabilitätsanalysen wies das BDI als Gesamtinstrument im Vergleich zu den vier BDI-Subskalen die höchste interne Konsistenz und die höchste Diskriminationsleistung auf. Von den Subskalen zeigte die BDI Short-Form von Beck und Steer (1993) die höchste Reliabilität und die beste Diskriminationsleistung. Für einen BDI-Gesamtwert von 12 als Cut-Off ergab sich eine hohe Sensitivität, bei einem Cut-Off von 15 dagegen ein ausgeglichenes Verhältnis zwischen Sensitivität, Spezifität und dem relativen Anteil an falsch klassifizierten Personen. Ein Cut-Off-Wert von 18 wies mit großer Wahrscheinlichkeit auf das Vorliegen einer affektiven Störung oder einer depressiven Anpassungsstörung hin. Für die BDI-Short Form ergaben sich entsprechend die Cut-Off-Werte 6, 8 und 10. Schlussfolgerung: Für die Erkennung depressiver Störungen bei KHK-Patienten sind das BDI und die BDI-Short Form gut geeignet. Der von Beck (1995) für das Gesamt-BDI vorgeschlagene Schwellenwert von 18 für die Erkennung klinisch relevanter Depression lässt sich auf KHK-Patienten übertragen.
Klassifikation von Verlaufskurven in der Depressionsbehandlung
Authors: Keller Ferdinand , Hautzinger Martin
Published: June 2007

Zusammenfassung. Theoretischer Hintergrund: Die Einteilung von Therapieverläufen depressiver Patienten in unterschiedliche Verlaufstypen ist von großem theoretischen und v.a. auch praktischen Wert, da eine frühzeitige Zuordnung therapeutische Konsequenzen nach sich ziehen könnte. Fragestellung: Ermöglichen neuere Ansätze aus der latenten Wachstumskurvenanalyse (“growth mixture modeling“ - GMM) eine Unterteilung in verschiedene Verlaufstypen? Ergeben sich Vorteile bei der Prädiktion der Entlasssymptomatik gegenüber einfachen klinischen Erfolgskriterien? Methode: Die Verlaufsdaten von n = 304 depressiven Patienten über acht Wochen hinweg werden mit zwei verschiedenen GMM-Ansätzen (semiparametrisch und parametrisch) in unterschiedliche Trajektorienklassen klassifiziert. Außerdem werden die Patienten nach einfachen klinischen Erfolgskriterien unterteilt. Ergebnisse: Im parametrischen Ansatz ergab sich eine Lösung mit vier Verlaufsklassen. Der semiparametrische Ansatz favorisierte eine analoge Lösung mit sieben Klassen, die z.T. parallel verliefen. Die Vorhersage der Entlasssymptomatik gelang mit GMM und dem klinischen Kriterium ähnlich gut. Schlussfolgerung: Die Klassifikation mit GMM erbrachte eine klinisch sinnvolle und gut zuordenbare Verlaufstypologie. Weitere klinische Möglichkeiten und Modellansätze werden diskutiert.
Die Identifikation früher Veränderungsmuster in der ambulanten Psychotherapie
Authors: Lutz Wolfgang , Stulz Niklaus , Smart David W. , Lambert Michael J.
Published: June 2007

Zusammenfassung. Theoretischer Hintergrund: Im Rahmen einer patientenorientierten Psychotherapieforschung werden Patientenausgangsmerkmale und Veränderungsmuster in einer frühen Therapiephase genutzt, um Behandlungsergebnisse und Behandlungsdauer vorherzusagen. Fragestellung: Lassen sich in frühen Therapiephasen verschiedene Muster der Veränderung (Verlaufscluster) identifizieren und durch Patientencharakteristika vorhersagen? Erlauben diese Verlaufscluster eine Vorhersage bezüglich Therapieergebnis und -dauer? Methode: Anhand des Growth Mixture Modeling Ansatzes wurden in einer Stichprobe von N = 2206 ambulanten Patienten einer US-amerikanischen Psychotherapieambulanz verschiedene latente Klassen des frühen Therapieverlaufs ermittelt und unter Berücksichtigung unterschiedlicher Patientenausgangscharakteristika als Prädiktoren der frühen Veränderungen mit dem Therapieergebnis und der Therapiedauer in Beziehung gesetzt. Ergebnisse: Für leicht, mittelschwer und schwer beeinträchtigte Patienten konnten je vier unterschiedliche Verlaufscluster mit jeweils spezifischen Prädiktoren identifiziert werden. Die Identifikation der frühen Verlaufsmuster ermöglichte weiterhin eine spezifische Vorhersage für die unterschiedlichen Verlaufscluster bezüglich des Therapieergebnisses und der Therapiedauer. Schlussfolgerungen: Frühe Psychotherapieverlaufsmuster können einen Beitrag zu einer frühzeitigen Identifikation günstiger sowie ungünstiger Therapieverläufe leisten.
Der Ecotainment-Index zur Messung der kognitiv-emotionalen Beteiligung an TV-Beiträgen
Authors: Schwender Clemens , Mocigemba Dennis , Otto Siegmar
Published: June 2007

Zusammenfassung. TV-Zuschauer/innen, die bislang Umwelt- und Nachhaltigkeits-Themen gegenüber resistent waren, sollen mithilfe des Ecotainment-Konzeptes erreicht werden. Dieses erfordert eine positive Auseinandersetzung auf kognitiv-emotionaler Ebene. Um TV-Beiträge zum Thema Nachhaltigkeit im Hinblick auf ihr kognitives und emotionales Wirkungspotenzial einschätzen zu können, wurde ein in der Praxis handhabbares Instrument entwickelt, das in der Lage ist, folgende wichtige Aspekte zu ermitteln: Werden Angebote für disperse Zuschauergruppen unterbreitet? Enthält der zu untersuchende Beitrag ausreichend Aspekte der Nachhaltigkeit? Wie reagieren Zuschauer/innen kognitiv und emotional auf die Beiträge?
Regional modeling of Saharan dust events using LM‐MUSCAT: Model description and case studies
Authors: Heinold B. , Helmert J. , Hellmuth O. , Wolke R. , Ansmann A. , Marticorena B. , Laurent B. , Tegen I.
Published: June 2007

A new regional model system was developed for simulation of emission, transport, deposition, and radiative effects of Saharan desert aerosol within the framework of the Saharan Mineral Dust Experiment (SAMUM). For this the mesoscale meteorological model LM, a dust emission scheme and a transport model were coupled. To test the model performance, two major Saharan dust outbreaks directed to Europe in August and October 2001 are simulated. Comparisons with sounding data and 10‐m wind speeds from north African sites show that the LM provides reliable meteorological fields to describe the emission and near‐source transport of dust. As shown by comparisons with satellite observations, lidar profiles, and Sun photometer measurements at selected stations, the spatiotemporal evolution of the dust plume is reasonably well reproduced by the model. The predicted dust interacts with the LM radiation at solar and thermal wavelengths. Saharan dust causes a negative effect on the net radiative budget at the top of the atmosphere in the source regions and accounts for a reduction in 10‐m wind speeds. Thus it is responsible for a reduction in the dust production of up to about 50% during the October 2001 event.
Comparison of water vapor measurements by airborne Sun photometer and near‐coincident in situ and satellite sensors during INTEX/ITCT 2004
Authors: Livingston J. , Schmid B. , Redemann J. , Russell P. B. , Ramirez S. A. , Eilers J. , Gore W. , Howard S. , Pommier J. , Fetzer E. J. , Seemann S. W. , Borbas E. , Wolfe D. E. , Thompson A. M.
Published: June 2007

We have retrieved columnar water vapor (CWV) from measurements acquired by the 14‐channel NASA Ames Airborne Tracking Sun photometer (AATS‐14) during 19 Jetstream 31 (J31) flights over the Gulf of Maine in summer 2004 in support of the Intercontinental Chemical Transport Experiment (INTEX)/Intercontinental Transport and Chemical Transformation (ITCT) experiments. In this paper we compare AATS‐14 water vapor retrievals during aircraft vertical profiles with measurements by an onboard Vaisala HMP243 humidity sensor and by ship radiosondes and with water vapor profiles retrieved from AIRS measurements during eight Aqua overpasses. We also compare AATS CWV and MODIS infrared CWV retrievals during five Aqua and five Terra overpasses. For 35 J31 vertical profiles, mean (bias) and RMS AATS‐minus‐Vaisala layer‐integrated water vapor (LWV) differences are −7.1% and 8.8%, respectively. For 22 aircraft profiles within 1 hour and 130 km of radiosonde soundings, AATS‐minus‐sonde bias and RMS LWV differences are −5.4% and 10.7%, respectively, and corresponding J31 Vaisala‐minus‐sonde differences are 2.3% and 8.4%, respectively. AIRS LWV retrievals within 80 km of J31 profiles yield lower bias and RMS differences compared to AATS or Vaisala retrievals than do AIRS retrievals within 150 km of the J31. In particular, for AIRS‐minus‐AATS LWV differences, the bias decreases from 8.8% to 5.8%, and the RMS difference decreases from 21.5% to 16.4%. Comparison of vertically resolved AIRS water vapor retrievals (LWVA) to AATS values in fixed pressure layers yields biases of −2% to +6% and RMS differences of ∼20% below 700 hPa. Variability and magnitude of these differences increase significantly above 700 hPa. MODIS IR retrievals of CWV in 205 grid cells (5 × 5 km at nadir) are biased wet by 10.4% compared to AATS over‐ocean near‐surface retrievals. The MODIS‐Aqua subset (79 grid cells) exhibits a wet bias of 5.1%, and the MODIS‐Terra subset (126 grid cells) yields a wet bias of 13.2%.
Characteristics of the double intertropical convergence zone over the tropical Indian Ocean
Authors: Meenu S. , Rajeev K. , Parameswaran K. , Suresh Raju C.
Published: June 2007

Investigations on the double intertropical convergence zone (DITCZ) over the Indian Ocean using the monthly mean surface wind divergence data obtained from scatterometers on board the ERS‐1/2 and QuikSCAT satellites (1991–2005) and the monthly mean cloud amount obtained from the International Satellite Cloud Climatology Project (1988–1989, 1998–2005) and the Advanced Very High Resolution Radiometer (AVHRR) data (1996–2003) reveal that its frequency of occurrence is considerably larger than that reported earlier, though the DITCZ feature in this region is rather diffused compared to Pacific. The 14‐year analysis of monthly mean surface wind divergence shows that DITCZ structure is clearly discernible in April (frequency of occurrence, f = 64%), November (f = 73%) and December (f = 60%) in the 50–85°E longitude band over the tropical Indian Ocean. Though less frequent, DITCZ occur during other months also, except the Asian summer monsoon season. Most preferred latitudes of the north and south bands of DITCZ are ∼6°N and ∼7°S, respectively, during November and December. The DITCZ structure is well manifested in the cloud amount also during November and December, while it is less prominent in April. A weak but clearly identifiable hemispherical asymmetry is observed in latitude of occurrence and amplitude of the DITCZ bands. Since the sea surface temperature (SST) at the equatorial region over the Indian Ocean is nearly uniform, the DITCZ appears to be generated mainly by the atmospheric dynamics. This provides a unique opportunity to investigate the structure of ITCZ created by the atmospheric dynamics alone, which is one of the important problems in ITCZ dynamics.
Observed emission rates in sprite streamer heads
Authors: Stenbaek‐Nielsen H. C. , McHarg M. G. , Kanmae T. , Sentman D. D.
Published: June 2007

Sprite observations at 10,000 fps have shown tendrils and branches to be formed by bright streamer heads moving at ∼107 m/s. The streamer heads typically brighten as they move up or down, often saturating the detector. We present here inferred emission rates. The streamer heads are presumably smaller than our 140 m spatial resolution and, therefore, they have to be treated as point sources. The optical emissions are assumed to be dominated by the N2 1P band and comparing with stars in the images we find total emission rates in individual streamer heads ranging from 4 1021 to 3 1024 photons/s. For a 25 m streamer head the range of average brightness would be 9 108–5 1011 R. Alternatively, using a volume emission rate of 8 1011 photons/cm3/s the size range would be 10 to 100 m.
Navier-Stokes equations with regularity in one direction
Authors: Kukavica Igor , Ziane Mohammed
Published: June 2007

We consider sufficient conditions for the regularity of Leray-Hopf solutions of the Navier-Stokes equations. We prove that if the third derivative of the velocity ∂u∕∂x3 belongs to the space Lts0Lxr0, where 2∕s0+3∕r0⩽2 and 9∕4⩽r0⩽3, then the solution is regular. This extends a result of Beirão da Veiga [Chin. Ann. Math., Ser. B 16, 407–412 (1995); C. R. Acad. Sci, Ser. I: Math. 321, 405–408 (1995)] by making a requirement only on one direction of the velocity instead of on the full gradient. The derivative ∂u∕∂x3 can be substituted with any directional derivative of u.
Effects of N incorporation on the structural and photoluminescence characteristics of GaSbN/GaSb single quantum wells
Authors: Iyer S. , Wu L. , Li J. , Potoczny S. , Matney K. , Kent P. R. C.
Published: June 2007

The structural and optical properties of GaSbN single quantum wells grown on GaSb substrates by solid source molecular beam epitaxy have been investigated for N concentrations up to 1.5%. The presence of well-resolved and pronounced Pendellosung fringes, dynamical diffraction rods seen in the corresponding reciprocal space map, and triple-axis x-ray full width at half maximum of 10–11 arcsec of the substrate and epilayer peak indicates epilayers of excellent quality with smooth interfaces. Low-temperature photoluminescence (PL) exhibited sharp and discrete N-related PL line features below the GaSb band edge. Their dependence on N concentration as well as measurement temperature and excitation intensity of the PL strongly suggests that these lines correspond to highly localized N pair/cluster states. No significant effect of in situ annealing in Sb ambient on the PL features was observed, while ex situ annealing in N ambient led to the annihilation of these features.
Metastable extension of the liquid-vapor phase equilibrium curve and surface tension
Authors: Baidakov V. G. , Protsenko S. P. , Kozlova Z. R. , Chernykh G. G.
Published: June 2007

The method of molecular dynamics has been used to calculate the parameters of liquid-vapor phase equilibrium and the surface tension in a two-phase system of 4096 Lennard-Jones particles. Calculations have been made in a range from the triple point to near-critical temperature and also at temperatures below the triple point corresponding to the metastable equilibrium of a supercooled liquid and supersaturated vapor. To determine the surface tension, along with a mechanical approach a thermodynamic one has been used as well. The latter was based on calculation of the excess internal energy of an interfacial layer. It has been shown that in accuracy the thermodynamic approach is as good as the more sophisticated mechanical one. Low-temperature asymptotics of the phase-equilibrium curve and also of liquid and vapor spinodals have been considered in the Lennard-Jones and the van der Waals models. The behavior of the surface tension and the excess internal energy of an interfacial layer at T→0 is discussed.
Photoabsorption spectra of boron nitride fullerenelike structures
Authors: Koponen Laura , Tunturivuori Lasse , Puska Martti J. , Nieminen Risto M.
Published: June 2007

Optical absorption spectra have been calculated for a series of boron nitride fullerenelike cage structures BnNn of sizes n=12–36. The method used is a real-time, real-space implementation of the time-dependent density-functional theory, involving the full time propagation of the time-dependent Kohn-Sham equations. The spectra are found to be a possible tool for distinguishing between different boron nitride fullerene species and isomers. The trends and differences in the spectra are found to be related to the general geometry of the molecules. Comparison between local-density and generalized-gradient approximations for electron exchange-correlation functionals shows that both of them produce essentially the same spectral characteristics.
Parallel Markov chain Monte Carlo simulations
Authors: Ren Ruichao , Orkoulas G.
Published: June 2007

With strict detailed balance, parallel Monte Carlo simulation through domain decomposition cannot be validated with conventional Markov chain theory, which describes an intrinsically serial stochastic process. In this work, the parallel version of Markov chain theory and its role in accelerating Monte Carlo simulations via cluster computing is explored. It is shown that sequential updating is the key to improving efficiency in parallel simulations through domain decomposition. A parallel scheme is proposed to reduce interprocessor communication or synchronization, which slows down parallel simulation with increasing number of processors. Parallel simulation results for the two-dimensional lattice gas model show substantial reduction of simulation time for systems of moderate and large size.
Modeling of structure and porosity in amorphous silicon systems using Monte Carlo methods
Authors: Opletal G. , Petersen T. C. , Snook I. K. , McCulloch D. G.
Published: June 2007

Porous solids are very important from a scientific point of view as they provide a medium in which to study the behavior of confined fluids. Although some porous solids have a well defined pore geometry such as zeolites, many porous solids lack crystalline order and are usually described as amorphous. The description of the pore geometry in such structures is very difficult. The authors develop a modeling approach using a Monte Carlo algorithm to simulate porosity within amorphous systems based on constraints for the internal volume and surface area. To illustrate this approach, a model of microporous amorphous silicon is presented. Structural aspects of the porous model are then compared against hybrid reverse Monte Carlo simulations of nonporous amorphous silicon and published results from the literature. It is found that coordination defects are predominately located at the pore surface walls.
Anomalous negative bias temperature instability behavior in p-channel metal-oxide-semiconductor field-effect transistors with HfSiON∕SiO2 gate stack
Authors: Chen Shih-Chang , Chien Chao-Hsin , Lou Jen-Chung
Published: June 2007

In this letter, the authors systematically investigated the behavior of negative bias temperature instability of p-channel metal-oxide-semiconductor field-effect transistors with HfSiON∕SiO2 gate stack. They found that typical linear extrapolation does not work well for the lifetime extraction at the normal operation conditions since the polarities of the net trapped charge inside the high-κ dielectrics are not the same at lower and higher stress voltage regimes. In other words, as ∣Vg∣<2.5V electron trapping dominated while hole trapping dominated when ∣Vg∣>2.5V. This phenomenon obviously contradicts the essence of the linear prediction in which the same degradation mechanism is assumed through the entire stress voltage range.
Micropumping of biofluids by alternating current electrothermal effects
Authors: Wu Jie , Lian Meng , Yang Kai
Published: June 2007

Electrokinetics is a preferred technique for microfluidic systems, but it is typically applied on fluids that are not too conductive (lower than 0.02S∕m), which excludes most biological applications. To solve this problem, this letter investigates microfluidic actuation by ac electrothermal (ACET) effect that was largely overlooked by the community. ACET originates from temperature gradients in the fluids, and it becomes more pronounced in more conductive fluids. This letter discusses two ACET pump designs, and pumping was demonstrated with biobuffers (e.g., lysogeny broth at 0.754S∕m).
Thermal energy exchange between carbon nanotube and air
Authors: Hu Ming , Shenogin Sergei , Keblinski Pawel , Raravikar Nachiket
Published: June 2007

Using molecular dynamics simulations the authors impose a heat flux between single-walled carbon nanotubes and air to study thermal interfacial conductance. They estimate that the nanotube-air interfacial thermal conductance is about 0.1MW∕m2K at room temperature and atmospheric pressure. The associated interfacial thermal resistance is equivalent to the resistance of 250nm thick layer of air. They also show that the interfacial resistance is a strong function of the interaction parameters between air atoms and carbon nanotubes.
Spectrally narrow emission from organic films under continuous-wave excitation
Authors: Nakanotani Hajime , Adachi Chihaya , Watanabe Sadayuki , Katoh Ryuzi
Published: June 2007

The authors observed a narrow emission from a 500-nm-thick codeposited organic thin film, 6wt% 4,4′-bis[(N-carbazole)styryl]-biphenyl (BSB-Cz) doped into a 4,4′-bis(N-carbazole)-biphenyl host, under continuous-wave excitation. Although they observed no clear threshold characteristics on the spectral narrowing, they found that the emission centered at a wavelength of λASE=462nm, corresponding to the zero to one transition of BSB-Cz, has a transverse electric mode with a narrow full width at half maximum of λFWHM=3.4nm, indicating the occurrence of amplified spontaneous emission. No excited state absorptions of singlet and triplet excited states of BSB-Cz are confirmed around λASE, leading to large net gain for the light amplification.
Electron holography of core-shell Co∕CoO spherical nanocrystals
Authors: Gao Youhui , Shindo Daisuke , Bao Yuping , Krishnan Kannan
Published: June 2007

Phase profiles of core-shell Co∕CoO nanocrystals are imaged using off-axis electron holography. Contributions of mean inner potential and magnetic induction to the phase shift are extracted, respectively, to quantitatively characterize the nanocrystal geometry and magnetic spin arrangement in a self-assembled nanocrystal chain. It is also found that the spin of 11nm diameter Co core encapsulated with 5-nm-thick CoO shell remains stable even at an elevated temperature of 200°C, indicating that the magnetically thermal stability of cobalt nanocrystals is remarkably improved due to the exchange coupling between the ferromagnetic core and antiferromagnetic shell.
Repeated sleep restriction in rats leads to homeostatic and allostatic responses during recovery sleep
Authors: Kim Youngsoo , Laposky Aaron D. , Bergmann Bernard M. , Turek Fred W.
Published: June 2007

Recent studies indicate that chronic sleep restriction can have negative consequences for brain function and peripheral physiology and can contribute to the allostatic load throughout the body. Interestingly, few studies have examined how the sleep–wake system itself responds to repeated sleep restriction. In this study, rats were subjected to a sleep-restriction protocol consisting of 20 h of sleep deprivation (SD) followed by a 4-h sleep opportunity each day for 5 consecutive days. In response to the first 20-h SD block on day 1, animals responded during the 4-h sleep opportunity with enhanced sleep intensity [i.e., nonrapid eye movement (NREM) delta power] and increased rapid eye movement sleep time compared with baseline. This sleep pattern is indicative of a homeostatic response to acute sleep loss. Remarkably, after the 20-h SD blocks on days 2–5, animals failed to exhibit a compensatory NREM delta power response during the 4-h sleep opportunities and failed to increase NREM and rapid eye movement sleep times, despite accumulating a sleep debt each consecutive day. After losing ≈35 h of sleep over 5 days of sleep restriction, animals regained virtually none of their lost sleep, even during a full 3-day recovery period. These data demonstrate that the compensatory/homeostatic sleep response to acute SD does not generalize to conditions of chronic partial sleep loss. We propose that the change in sleep–wake regulation in the context of repeated sleep restriction reflects an allostatic process, and that the allostatic load produced by SD has direct effects on the sleep–wake regulatory system.
nanos
gene control DNA mediates developmentally regulated transposition in the yellow fever mosquito
Aedes aegypti
Authors: Adelman Zach N. , Jasinskiene Nijole , Onal Sedef , Juhn Jennifer , Ashikyan Aurora , Salampessy Michael , MacCauley Todd , James Anthony A.
Published: June 2007

Transposable elements (TEs) are proposed as a basis for developing drive systems to spread pathogen resistance genes through vector mosquito populations. The use of transcriptional and translational control DNA elements from genes expressed specifically in the insect germ line to mediate transposition offers possibilities for mitigating some of the concerns about transgene behavior in the target vector species and eliminating effects on nontarget organisms. Here, we describe the successful use of the promoter and untranslated regions from the
nanos
(
nos
) orthologous gene of the yellow fever mosquito,
Aedes aegypti
, to control sex- and tissue-specific expression of exogenously derived
mariner
MosI transposase-encoding DNA. Transgenic mosquitoes expressed transposase mRNA in abundance near or equal to the endogenous
nos
transcript and exclusively in the female germ cells. In addition, MosI mRNA was deposited in developing oocytes and localized and maintained at the posterior pole during early embryonic development. Importantly, four of five transgenic lines examined were capable of mobilizing a second MosI transgene into the mosquito genome, indicating that functional transposase was being produced. Thus, the
nos
control sequences show promise as part of a TE-based gene drive system.
Herpes simplex virus glycoproteins gB and gH function in fusion between the virion envelope and the outer nuclear membrane
Authors: Farnsworth Aaron , Wisner Todd W. , Webb Michael , Roller Richard , Cohen Gary , Eisenberg Roselyn , Johnson David C.
Published: June 2007

Herpesviruses must traverse the nuclear envelope to gain access to the cytoplasm and, ultimately, to exit cells. It is believed that herpesvirus nucleocapsids enter the perinuclear space by budding through the inner nuclear membrane (NM). To reach the cytoplasm these enveloped particles must fuse with the outer NM and the unenveloped capsids then acquire a second envelope in the trans-Golgi network. Little is known about the process by which herpesviruses virions fuse with the outer NM. Here we show that a herpes simplex virus (HSV) mutant lacking both the two putative fusion glycoproteins gB and gH failed to cross the nuclear envelope. Enveloped virions accumulated in the perinuclear space or in membrane vesicles that bulged into the nucleoplasm (herniations). By contrast, mutants lacking just gB or gH showed only minor or no defects in nuclear egress. We concluded that either HSV gB or gH can promote fusion between the virion envelope and the outer NM. It is noteworthy that fusion associated with HSV entry requires the cooperative action of both gB and gH, suggesting that the two types of fusion (egress versus entry) are dissimilar processes.
Molecular dynamics using atomic-resolution structure reveal structural fluctuations that may lead to polymerization of human Cu–Zn superoxide dismutase
Authors: Strange Richard W. , Yong Chin W. , Smith William , Hasnain S. Samar
Published: June 2007

Mutations of the gene encoding Cu–Zn superoxide dismutase (SOD1) cause 20% of the familial cases of the progressive neurodegenerative disease ALS. A growing body of evidence suggests that in familial ALS (FALS) it is the molecular behavior of the metal-depleted SOD1 dimer that leads to a gain of toxic properties by misfolding, unfolding, and aggregation. Structural studies have so far provided static snapshots on the behavior of the wild-type enzyme and some of the FALS mutants. New approaches are required to map out the structural trajectories of the molecule. Here, using our 1.15-Å resolution structure of fully metallated human SOD1 and highly parallelized molecular dynamics code on a high-performance capability computer, we have undertaken molecular dynamics calculations to 4,000 ps to reveal the first stages of misfolding caused by metal deletion. Large spatial and temporal fluctuations of the “electrostatic” and “Zn-binding” loops adjacent to the metal-binding sites are observed in the apo-enzyme relative to the fully metallated dimer. These early misfolding events expose the β-barrels of the dimer to the external environment, allowing close interactions with adjacent molecules. Protection of the β-edge of the protein can be partially restored by incorporating a single Zn molecule per dimer. These calculations reveal an essential step in the formation of the experimentally observed self-aggregations of metal-depleted FALS mutant SOD1. This result also has implications for the role of demetallated wild-type SOD1 in sporadic cases of ALS, for which the molecular cause still remains undiscovered.
Bone morphogenetic protein 1 processes prolactin to a 17-kDa antiangiogenic factor
Authors: Ge Gaoxiang , Fernández Cecilia A. , Moses Marsha A. , Greenspan Daniel S.
Published: June 2007

In addition to classical expression patterns in pituitary and placenta and functions in growth and reproduction, members of the small family of hormones that includes prolactin (PRL), growth hormone (GH), and placental lactogen are expressed by endothelia and have angiogenic effects. In contrast, 16- to 17-kDa proteolytic fragments of these hormones have antiangiogenic effects. Here we show that PRL and GH are bound and processed by members of the bone morphogenetic protein 1 (BMP1) subgroup of extracellular metalloproteinases, previously shown to play key roles in forming extracellular matrix and in activating certain TGFβ superfamily members. BMP1 has previously been suggested to play roles in angiogenesis, as high throughput screens have found its mRNA to be one of those induced to highest levels in tumor-associated endothelia compared with resting endothelia. PRL and GH cleavage is shown to occur in each hormone at a single site typical of sites previously characterized in known substrates of BMP1-like proteinases, and the ≈17-kDa PRL N-terminal fragment so produced is demonstrated to have potent antiangiogenic activity. Mouse embryo fibroblasts are shown to produce both PRL and GH and to process them to ≈17-kDa forms, whereas GH and PRL processing activity is lost in mouse embryo fibroblasts doubly null for two genes encoding BMP1-like proteinases.