bluuebunny/crossref_metadata_2025 huggingface dataset:
Iso-surface mass flow density and its implications for turbulent mixing and combustion
Authors: KIM SEUNG HYUN , BILGER ROBERT W.
Published: October 2007

A new result is derived for the mass flow rate per unit volume through a scalar iso-surface – called here the ‘iso-surface mass flow density’. The relationship of the surface mass flow density to the local entrainment rate per unit volume in scalar mixing and to the local reaction rate in turbulent premixed combustion is considered. In inhomogeneous flows, integration of the surface mass flow density across the layer in the direction of the mean scalar inhomogeneity yields the mean entrainment velocity in scalar mixing and the turbulent burning velocity in premixed combustion. For non-premixed turbulent reacting flow, this new result is shown to be consistent with the classical result of Bilger (Combust. Sci. Technol. vol. 13, 1976, p. 155) for fast one-step irreversible chemical reactions. Direct numerical simulation data for conserved scalar mixing, isothermal reaction front propagation and turbulent premixed flames are analysed. It is found that the entrainment velocity in the conserved scalar mixing case is sensitive to a threshold value. This suggests that the entrainment velocity is not a well-defined concept in temporally developing mixing layers and that scaling laws for the viscous superlayer warrant further investigation. In the isothermal reaction fronts problem, the characteristics of iso-surface propagation in a low Damköhler number regime are investigated. In premixed flames, the effects of non-stationarity on the turbulent burning velocity are addressed. The difference from the existing methods for determining turbulent burning velocity, and the implications of the present results for flames with multi-dimensional complex geometry are discussed. It is also shown that the surface mass flow density is related to the turbulent scalar flux in statistically stationary one-dimensional premixed flames. Variations of the local propagation characteristics due to departure from an unstretched laminar flame structure are shown to decrease the tendency to counter-gradient transport in turbulent premixed flames.
A diffuse-interface model for electrowetting drops in a Hele-Shaw cell
Authors: LU H.-W. , GLASNER K. , BERTOZZI A. L. , KIM C.-J.
Published: October 2007

Electrowetting has recently been explored as a mechanism for moving small amounts of fluids in confined spaces. We propose a diffuse-interface model for drop motion, due to electrowetting, in a Hele-Shaw geometry. In the limit of small interface thickness, asymptotic analysis shows that the model is equivalent to Hele-Shaw flow with a voltage-modified Young–Laplace boundary condition on the free surface. We show that details of the contact angle significantly affect the time scale of motion in the model. We measure receding and advancing contact angles in the experiments and derive their influence through a reduced-order model. These measurements suggest a range of time scales in the Hele-Shaw model which include those observed in the experiment. The shape dynamics and topology changes in the model agree well with the experiment, down to the length scale of the diffuse-interface thickness.
Early Meiji Policies Towards the Ryukyus and the Taiwanese Aboriginal Territories
Authors: MIZUNO NORIHITO
Published: October 2007

This article focuses on Meiji Japan's policies towards the Ryukyus and the Taiwanese aboriginal territories in the early 1870s. The Meiji Government incorporated the Ryukyus by abolishing the kingdom in 1872 and sent expeditionary forces to the Taiwanese aboriginal territories on the pretext of the massacre of the shipwrecked Ryukyuans by the aboriginal tribes in 1874. Many Japanese and non-Japanese historians have argued that Japan started aggression on China by annexing its tributary state and invading its territories. In this article, I contend that the Ryukyu–Taiwan policies in the early Meiji period grew out of Japanese concerns over national security and prestige in a Western-dominated international environment but had no intention to secure Japan's independence and to aggrandise its national prestige by encroaching on China's territorial sovereignty.
Does an encouraging letter encourage attendance at psychiatric out-patient clinics? The Leeds PROMPTS randomized study
Authors: Kitcheman J. , Adams C. E. , Pervaiz A. , Kader I. , Mohandas D. , Brookes G.
Published: October 2007

Background

The aim was to reduce non-attendance for first-time consultations at psychiatric out-patient clinics.

Method

The study was a pragmatic randomized controlled trial; the setting was seven inner-city UK out-patient clinics in Leeds. The participants were 764 subjects of working age with an appointment to attend a psychiatric out-patient clinic for the first time. The intervention was an ‘orientation statement’ letter delivered 24–48 h before the first appointment compared with standard care. The primary outcome measure was attendance at the first appointment; secondary outcomes included hospitalization, transfer of care, continuing attendance, discharge, presentation at accident and emergency and death by 1 year.

Results

Follow-up was for 763 out of 764 subjects (>99%) for primary and for 755 out of 764 subjects (98.8%) of secondary outcome data. The orientation statement significantly reduced the numbers of people failing to attend [79 out of 388 v. 101 out of 376 subjects, relative risk 0.76, 95% confidence interval (CI) 0.59–0.98, number needed to treat 16, 95% CI 10–187].

Conclusions

Prompting people to go to psychiatric out-patient clinics for the first time encourages them to attend. Pragmatic trials within a busy working environment are possible and informative.
Urban residence, victimhood and the appraisal of personal safety in people with schizophrenia: results from the European Schizophrenia Cohort (EuroSC)
Authors: Schomerus G. , Heider D. , Angermeyer M. C. , Bebbington P. E. , Azorin J.-M. , Brugha T. , Toumi M.
Published: October 2007

Background

Patients with schizophrenia are at increased risk of being victims of violent and non-violent crimes. We have determined how the experience of crime and subjective feelings of safety differ between urban and rural residential areas.

Method

We analysed data from the European Schizophrenia Cohort (EuroSC), a 2-year follow-up study of 1208 patients in the UK, France and Germany. Subjective safety and a history of victimhood were elicited with Lehman's Quality of Life Inventory. Regression models adjusted the effects of living environment for country, education, employment, financial situation, drug and alcohol abuse, criminal arrests and the level of schizophrenic symptoms.

Results

Ten per cent of patients were victims of violent and 19% of non-violent crimes. There was no significant relationship between victim status and residential area. However, subjective safety was clearly worse in cities than in rural areas. Aspects of objective and subjective safety were related to different factors: being the victim of violence was most strongly associated with alcohol and drug abuse and with criminal arrests of the patients themselves, whereas impaired subjective safety was most strongly associated with poverty and victimhood experience.

Conclusions

Although urban living was not associated with increased objective threats to their security, patients did feel more threatened. Such stress and anxiety can be related to concepts of social capital, and may contribute unfavourably to the course of the illness, reflecting the putative role of appraisal in cognitive models of psychosis. Securing patients’ material needs may provide a way to improve subjective safety.
Differential criterion functioning of alcohol use symptomatology in major depressive disorder?
Authors: Lynskey M. T. , Agrawal A.
Published: October 2007

Background

Major depressive disorder (MDD) and alcohol use disorders (AUDs) are among the most prevalent psychiatric disorders and are frequently co-morbid. However, some component of this co-morbidity may be artifactual and arise from the influence of current mental state on self-reports of AUD.

Method

This study examined whether past-year MDD is associated with differential criterion functioning (DCF) in reports of AUD symptomatology in male and female participants in the National Epidemiological Survey on Alcohol and Related Conditions (NEASRC).

Results

Reports of past-year AUD symptomatology were adequately summarized by a single-factor model in which each of the 11 abuse and dependence criteria had high factor loadings (0.71–0.93) and did not vary between men and women after allowing for threshold differences. Co-morbid MDD was associated with higher AUD mean scores. There was some evidence for DCF with past-year MDD being associated with a lower endorsement of use in hazardous situations among men whereas women with MDD were more likely to endorse both social/interpersonal problems and emotional/physical problems.

Conclusions

Several items assessing AUD display DCF in the presence of MDD. While these findings highlight the need to consider the possibility that mental state can influence reporting of psychiatric symptoms and potentially inflate estimates of co-morbidity, they suggest that only a negligible component of the co-morbidity between MDD and AUDs can be attributed to over-reporting of alcohol symptomatology conditional on current MDD.
Psychotic-like experiences and other antecedents of schizophrenia in children aged 9–12 years: a comparison of ethnic and migrant groups in the United Kingdom
Authors: Laurens K. R. , West S. A. , Murray R. M. , Hodgins S.
Published: October 2007

Background

The incidence of schizophrenia and the prevalence of psychotic symptoms in the general adult population are elevated in migrant and ethnic minority groups relative to host populations. These increases are particularly prominent among African-Caribbean migrants to the UK. This study examined the associations of ethnicity and migrant status with a triad of putative antecedents of schizophrenia in a UK community sample of children aged 9–12 years. The antecedent triad comprised: (i) psychotic-like experiences; (ii) a speech and/or motor developmental delay or abnormality; and (iii) a social, emotional or behavioural problem.

Method

Children (n=595) and their primary caregivers, recruited via schools and general practitioners in southeast London, completed questionnaires. Four indices of risk were examined for associations with ethnicity and migrant status: (i) certain experience of at least one psychotic-like experience; (ii) severity of psychotic-like experiences (total psychotic-like experience score); (iii) experience of the antecedent triad; and (iv) severity of antecedent triad experiences (triad score).

Results

African-Caribbean children, as compared to white British children, experienced greater risk on all four indices. There were trends for South Asian and Oriental children to present lowered risk on several indices, relative to white British children. Migration status was unrelated to any risk index.

Conclusion

Prevalence of the putative antecedents of schizophrenia is greater among children of African-Caribbean origin living in the UK than among white British children. This parallels the increased incidence of schizophrenia and elevated prevalence of psychotic symptoms among adults of African-Caribbean origin.
Family study of subthreshold psychopathology in a community sample
Authors: Shankman S. A. , Klein D. N. , Lewinsohn P. M. , Seeley J. R. , Small J. W.
Published: October 2007

Background

There has been increasing interest in the validity and familial transmission of subthreshold psychiatric conditions and the relationship between subthreshold conditions and full syndrome (FS) disorders. However, most of these studies examined a single subthreshold condition and thus fail to take into account the high co-morbidity among subthreshold conditions and between subthreshold conditions and FS disorders.

Method

A family study of subthreshold psychiatric conditions was conducted with 739 community-drawn young adults and their 1744 relatives. We examined (1) whether relatives of probands with subthreshold major depression, bipolar disorder, anxiety disorders, alcohol use, substance use, and/or conduct disorder exhibited an increased rate of the corresponding (homotypic) FS disorder; (2) whether subthreshold disorders were associated with increased familial rates of other (heterotypic) FS disorders; (3) whether subthreshold and FS conditions are associated with similar familial liabilities; and (4) whether these homotypic and heterotypic associations persisted after controlling for co-morbidity.

Results

Significant homotypic associations were observed for subthreshold anxiety, alcohol, conduct, and a trend was observed for major depression. Only the homotypic association for alcohol and conduct remained after controlling for co-morbid subthreshold and FS conditions. Many heterotypic associations were observed and most remained after controlling for co-morbidity.

Conclusions

It is important to broaden the study of subthreshold psychopathology to multiple disorders. In particular cases, controlling for co-morbidity with other subthreshold and FS conditions altered the patterns of familial aggregation. Etiological processes that are common to particular disorders and subthreshold conditions are discussed.
The influence of an intense laser beam interaction with preformed plasma on the characteristics of emitted ion streams
Authors: Láska L. , Badziak J. , Gammino S. , Jungwirth K. , Kasperczuk A. , Krása J. , Krouský E. , Kubeš P. , Parys P. , Pfeifer M. , Pisarczyk T. , Rohlena K. , Rosinski M. , Ryc´ L. , Skála J. , Torrisi L. , Ullschmied J. , Velyhan A. , Wolowski J.
Published: October 2007

Intense laser-beam interactions with preformed plasma, preceding the laser-target interactions, significantly influence both the ion and X-ray generation. It is due to the laser pulse (its total length, the shape of the front edge, its background, the contrast, the radial homogeneity) as well as plasma (density, temperature) properties. Generation of the super fast (FF) ion groups is connected with a presence of non-linear processes. Saturated maximum of the charge states (independently on the laser intensity) is ascribed to the constant limit radius of the self-focused laser beam. Its longitudinal structure is considered as a possible explanation for the course of some experimental dependencies obtained.
Equation of state and optimum compression in inertial fusion energy
Authors: Eliezer S. , Murakami M. , Martinez Val J.M.
Published: October 2007

The inertial confinement fusion (ICF) philosophy is based on high compression. The reasoning is that (a) it is cheaper (energetically) to compress than to heat and (b) nuclear reactions are proportional to density square, therefore the more you compress the better you are in ICF. Of course the only limitations of compression are the hydrodynamic instabilities (like Rayleigh-Taylor, etc). Many of the references in the literature require extremely high compression and in particular the pB11 needs extremely huge compressions. In this paper it is shown that there is an optimum of compression, namely gain G is maximum for a definite compression. The value of this density (for a given fuel mass and particular ICF scheme) depends on the equation of state (EOS). We calculate this value for fast ignition (FI) schemes and compare it with the central spark ignition (CSI) model. The gain calculations are based on the ideal gas for the ions and the Fermi-Dirac EOS for the electrons with an effective alpha, as usually suggested from simulations. The “optimum compression” idea is easily understood from the following argument: From EOS data one needs an infinite energy to compress to an infinite density. Since the energy output is finite it is clear that G is zero for infinite compression. On the other hand for normal density with small fuel mass (~ few mg) the gain is also zero. Therefore a maximum should exist somewhere. For the deuterium-tritium fuel with a mass of few mg one gets an optimum at few hundred g/cc. If you compress more then the gain is going down. So there is a desired maximum compression fixed by EOS. Last but not least, bremsstrahlung losses in degenerate plasma are discussed and the clean fusion (i.e., without neutrons) of proton + B11 → 4α is analyzed.
Numerical simulations of the projectile ion charge difference in solid and gaseous stopping matter
Authors: Eisenbarth S. , Rosmej O.N. , Shevelko V.P. , Blazevic A. , Hoffmann D.H.H.
Published: October 2007

The dependence of calcium ion subshell populations on the target density during the ion stopping process was analyzed using a five charge-state collisional-radiative model. The model, which consists of the ground and three excited states for every ion charge, was successfully compared with the experiment. The gas-solid difference of calcium ion charge state distribution has been numerically demonstrated. For Ca projectiles with energies of 4–11 MeV/u, the increase of the mean ion charge in solid target is explained by the increase of the total ionization rate and by suppression of the bound electron capture process at high densities of the stopping medium.
Holistic Simulation for FIREX Project with FI3
Authors: Johzaki T. , Sakagami H. , Nagatomo H. , Mima K.
Published: October 2007

In fast ignition research, the clarification of core heating mechanism is one of the most critical issues. To understand and identify the crucial physics in fast heating, we developed the fast ignition integrated interconnecting code FI3 and carried out the core heating simulations for fast heating experiments with cone-guided targets. It was found that the scale length of the pre-plasma at the inner-surface of the cone and the density gap at the contact surface between the cone tip and the imploded core plasma strongly affect the efficiency of core heating. In the case of heating laser with intensity of 1020 W/cm2 and duration of 1 ps, the pre-plasma scale length of 1.5 µm is optimum for the core heating; the dense core is heated up to 0.86 keV. In the double scale length case (long scale of ~5 µm in underdense region and short scale of ~ 1 µm in overdense region), of which generation due to the pre-pulse irradiation of heating pulse is observed at the radiation–hydro simulations, the dense core is heated more efficiently than single short scale length cases. The contribution of fast ions to the core heating is also discussed.
Intense local plasma heating by stopping of ultrashort ultraintense laser pulse in dense plasma
Authors: Yu W. , Yu M. Y. , Xu H. , Tian Y. W. , Chen J. , Wong A. Y.
Published: October 2007

Self-trapping, stopping, and absorption of an ultrashort ultraintense linearly polarized laser pulse in a finite plasma slab of near-critical density is investigated by particle-in-cell simulation. As in the underdense plasma, an electron cavity is created by the pressure of the transmitted part of the light pulse and it traps the latter. Since the background plasma is at near-critical density, no wake plasma oscillation is created. The propagating self-trapped light rapidly comes to a stop inside the slab. Subsequent ion Coulomb explosion of the stopped cavity leads to explosive expulsion of its ions and formation of an extended channel having extremely low plasma density. The energetic Coulomb-exploded ions form shock layers of high density and temperature at the channel boundary. In contrast to a propagating pulse in a lower density plasma, here the energy of the trapped light is deposited onto a stationary and highly localized region of the plasma. This highly localized energy-deposition process can be relevant to the fast ignition scheme of inertial fusion.
Kinematic reductions for uncertain mechanical contact
Authors: Murphey Todd D.
Published: October 2007

This paper describes the methods applicable to the modeling and control of mechanical contact, particularly those systems that experience uncertain stick/slip phenomena. Geometric kinematic reductions are used to reduce a system's description from a second-order dynamic model with frictional disturbances coming from a function space to a first-order model with frictional disturbances coming from a space of finite automata over a finite set. As a result, modeling for purposes of control is made more straight-forward by getting rid of some dependencies on low-level mechanics (in particular, the details of friction modeling). Moreover, the online estimation of the uncertain, discrete-valued variables has reduced sensing requirements. The primary contributions of this paper are the introduction of a simplifying representation of friction and formal tests for kinematic reducibility. Results are illustrated using a slip-steered vehicle model and an actuator array model.
Influence of temperature and moisture availability on physical rock weathering along the Victoria Land coast, Antarctica
Authors: Elliott Christine
Published: October 2007

Rock weathering plays an important role in soil development. A better understanding of how different temperature and moisture regimes impact on the rates of rock breakdown can thus contribute to our knowledge of how rates of soil production might be affected by changes in climate. Laboratory simulations using two temperature cycles determined from field data and three moisture levels were carried out on samples of granite from three locations along the Victoria Land coast. Estimates of weathering rate from these experiments were of the same order of magnitude as some other more field based studies undertaken in similar environments. However, actual values for samples from the three locations varied depending on the specific characteristics of the rock, especially grain size, porosity and extent of micro-cracking. Moisture availability was found to be an important factor in determining weight loss in the samples from Gneiss Point but not in those from Terra Nova Bay or Teall Island with the moderate level of moisture application having the greatest impact. Spring/autumn temperature cycles had a different effect on the breakdown of the rock samples compared to summer cycles but the magnitude of the effect was dependent on moisture level and rock characteristics, especially quartz content and the ability to absorb heat and moisture. The samples of rock from Terra Nova Bay and Gneiss Point where no moisture had been applied had significantly higher rates of breakdown under spring/autumn cycles than summer ones. However, this effect was reversed in the Gneiss Point samples after moisture was added. A future climate scenario using the weathering rates found in this research where there was, for example, a 10% increase in summer temperature cycles and a corresponding decrease in spring/autumn cycles predicted that a reduction in weathering would occur in conditions of little or no precipitation at Terra Nova Bay and Gneiss Point but there would be limited effect under higher levels of moisture.
Factors affecting food choice in Greek primary-school students: ELPYDES study
Authors: Risvas Grigoris , Panagiotakos Demosthenes B , Zampelas Antonis
Published: October 2007

Objective

To measure factors affecting food choice in a sample of Greek schoolchildren attending 5th and 6th grade.

Design

Three self-administered questionnaires were distributed to the participants – one on nutritional knowledge, one on self-efficacy and social support for dietary change and a food-frequency questionnaire.

Setting

One hundred Greek primary schools from Attica and Thessaloniki regions.

Subjects

In total, 2439 students in 5th and 6th grades.

Results

Principal components analysis was applied to extract the main factors affecting food choice of our subjects. Six components were derived explaining 66% of the total variation in factors affecting food choice. The first component was characterised by readiness to make the healthier choice when competitive foods are considered (explained variation 29%); the second was characterised by the impact of parents, friends and advertisements on students’ choices and also the impact of taste, smell and cooking method on the consumption of vegetables (explained variation 11%); the third component was characterised by readiness to choose fresh foods instead of ready-to-eat, pre-packaged choices as a main meal and awareness of the health value of fruits and vegetables (explained variation 8%); the other components mainly expressed the interdependence of the main factors.

Conclusions

Nutrition education and health promotion programs in Greece must include family members and activities regarding food preparation, as well as education and environmental changes in schools. Public health measures must include regulation of advertising. Moreover, the categorisation of foods as ‘healthier but less tasty’ and ‘appealing but unhealthy’ needs to be challenged in the future, since balanced nutrition is founded in variety and norm.
Targeting the lipids LPA and S1P and their signalling pathways to inhibit tumour progression
Authors: Murph Mandi , Mills Gordon B.
Published: October 2007

The bioactive lipids lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P), the enzymes that generate and degrade them, and the receptors that receive their signals are all potential therapeutic targets in cancer. LPA and S1P signalling pathways can modulate a range of cellular processes that contribute to tumourigenesis, such as proliferation and motility, and components of the signalling pathways often show aberrant expression and altered activity upon malignant transformation. This article reviews LPA- and S1P-mediated activities that might contribute to the aetiology of cancer, and examines the potential of the many antagonists that have been developed to inhibit LPA and S1P signalling pathways. In addition, the outcomes of various clinical trials using LPA- and S1P-associated targets in cancer and other diseases are described, and future directions are discussed.
Pubertäres Timing bei Mädchen und Folgen in der späten Adoleszenz
Authors: Büttig Sabine , Weichold Karina , Silbereisen Rainer K.
Published: October 2007

Zusammenfassung. Der vorliegende Beitrag befasst sich mit den Folgen körperlicher Früh- und Spätentwicklung für die psychosoziale Entwicklung von Mädchen ausgangs der Adoleszenz. Es wurden 49 Mädchen im Alter zwischen 9 und 15 Jahren (M = 11.85, SD = 1.10) untersucht und im Abstand von sechs Jahren erneut befragt. Eingangs der Adoleszenz wurde das objektivierte Entwicklungstempo bestimmt und ausgangs der Adoleszenz retrospektiv die Konsistenz subjektiver Abweichungen im pubertären Timing erfasst. Zielvariablen waren depressive Verstimmung und Ängstlichkeit, die Individuation im familiären System sowie soziale Unterstützung innerhalb und außerhalb der Familie. Die Befunde zeigen, dass das pubertäre Entwicklungstempo in der vorliegenden Stichprobe nicht mit internalisierten Symptomen verbunden ist. Mädchen mit konsistent beschleunigtem Timing streben jedoch ausgangs der Adoleszenz verglichen mit gleichaltrigen Jugendlichen stärker nach Autonomie. Weiterhin erhalten Mädchen, die eingangs der Adoleszenz objektiviert frühpubertierend waren, ausgangs der Jugendzeit weniger soziale Unterstützung.
Schulleistungen monolingual und immersiv unterrichteter Kinder am Ende des ersten Schuljahres
Authors: Zaunbauer Anna C. M. , Möller Jens
Published: October 2007

Zusammenfassung. In der vorliegenden Studie werden die Effekte früher Teilimmersion (Englischsprachiger Unterricht in allen Fächern außer in Deutsch) auf den Erwerb des Lesens und Schreibens (in der Erstsprache) und des Rechnens im ersten Schuljahr untersucht. N = 139 Erstklässler, die entweder monolingual oder teilimmersiv unterrichtet werden, wurden zu zwei Zeitpunkten innerhalb des ersten Schuljahres getestet. In der ersten Hälfte des Schuljahres wurden neben familiären Hintergrundvariablen und vorschulischen Aktivitäten (Lesen/Schreiben, Rechnen) die Konzentrationsleistung, die nonverbale Intelligenz, das Verbalgedächtnis sowie das Interesse und das Selbstkonzept für die Schulfächer Deutsch (Lesen/Schreiben) und Mathematik erfasst. Gegen Ende des Schuljahres wurden deutschsprachige Tests in den Fächern Deutsch und Mathematik durchgeführt. Für die teilimmersiv unterrichteten Schüler ergaben sich keine Defizite im Lesen und Schreiben; ihre Mathematikleistungen waren denen der monolingual unterrichteten Schüler überlegen. Die Ergebnisse werden vor dem Hintergrund reflektiert, dass sich monolingual und immersiv unterrichtete Schüler hinsichtlich des familiären Bildungsniveaus sowie hinsichtlich der nonverbalen Intelligenztestleistungen sowie des Verbalgedächtnisses unterscheiden. Sie werden zudem mit Bezug zu J. Cummins’ Interdependenz-Hypothese (1979) diskutiert.
Ontogenetische Entwicklung im Kindesalter beim Richtungszeigen in vertrauter Umgebung
Authors: Neidhardt Eva
Published: October 2007

Zusammenfassung. In einer kombinierten Querschnitts- und Längsschnittstudie werden die Zeigeleistungen von Vorschul- und Grundschulkindern im vertrauten Gelände um Kindergarten oder Schule untersucht und in Bezug auf alters- und geschlechtsbezogene Effekte analysiert. Mit beiden Vergleichsdesigns kann auf einen leichten alterskorrelierten Leistungszuwachs geschlossen werden.
Seasonal circulation around Tasmania: An interface between eastern and western boundary dynamics
Authors: Ridgway K. R.
Published: October 2007

The seasonal circulation connecting the Pacific and Indian oceans around Tasmania is documented using seasonal maps from satellite altimetry and sea surface temperature (SST) and in situ mean fields from a high‐resolution climatology of the region (Commonwealth Scientific and Industrial Research Organisation (CSIRO) Atlas of Regional Seas (CARS)). In general, the surface variability displays a very different character off the east and west coasts. Off the east coast the variability is generated externally, being dominated by the western boundary dynamics of the East Australian Current (EAC). In the west it is weaker and arises from the seasonal rise and fall of the coastal sea level, which is due to the seasonal reversing wind patterns. A high‐variability tongue associated with the EAC stretches poleward off the east coast, tracing out a waveguide between the major topographic structures. It has a broad peak in power between 180 and 365 days (>0.08 m), which is a surface height expression of the energetic mesoscale eddy activity associated with the EAC. Distinctive summer and winter patterns of the surface circulation are described which are influenced by the EAC and the Zeehan Current (ZC), respectively. On the east coast in summer (January–March), there is a poleward advection of warm, saline water forced by an episodic coastal boundary flow. The cross‐shelf pressure gradient driving this flow is formed from the difference between the seasonal changes in coastal sea level and the offshore eddies. There is a seasonal reversal of this flow in winter with cool, fresh, modified subantarctic surface waters drawn up from the south. Off the west coast the Zeehan Current operates 180° out of phase with the EAC. It is strongest in winter when it projects warm, relatively saline waters down the western Tasmania coast and around the southern tip of Tasmania. There is a sharp division between the EAC and ZC influence adjacent to the Tasman Peninsula off southeast Tasmania.
Influence of savanna fire on Australian monsoon season precipitation and circulation as simulated using a distributed computing environment
Authors: Lynch Amanda H. , Abramson David , Görgen Klaus , Beringer Jason , Uotila Petteri
Published: October 2007

Fires in the Australian savanna have been hypothesized to affect monsoon evolution, but the hypothesis is controversial and the effects have not been quantified. A distributed computing approach allows the development of a challenging experimental design that permits simultaneous variation of all fire attributes. The climate model simulations are distributed around multiple independent computer clusters in six countries, an approach that has potential for a range of other large simulation applications in the earth sciences. The experiment clarifies that savanna burning can shape the monsoon through two mechanisms. Boundary‐layer circulation and large‐scale convergence is intensified monotonically through increasing fire intensity and area burned. However, thresholds of fire timing and area are evident in the consequent influence on monsoon rainfall. In the optimal band of late, high intensity fires with a somewhat limited extent, it is possible for the wet season to be significantly enhanced.
Initial soil moisture retrievals from the METOP‐A Advanced Scatterometer (ASCAT)
Authors: Bartalis Zoltan , Wagner Wolfgang , Naeimi Vahid , Hasenauer Stefan , Scipal Klaus , Bonekamp Hans , Figa Julia , Anderson Craig
Published: October 2007

This article presents first results of deriving relative surface soil moisture from the METOP‐A Advanced Scatterometer. Retrieval is based on a change detection approach which has originally been developed for the Active Microwave Instrument flown onboard the European satellites ERS‐1 and ERS‐2. Using model parameters derived from eight years of ERS scatterometer data, first global soil moisture maps have been produced from ASCAT data. The ASCAT data were distributed by EUMETSAT for validation purposes during the ASCAT product commissioning activities. Several recent cases of drought and excessive rainfall are clearly visible in the soil moisture data. The results confirm that seamless soil moisture time series can be expected from the series of two ERS and three METOP scatterometers, providing global coverage on decadal time scales (from 1991 to about 2021). Thereby, operational, near‐real‐time ASCAT soil moisture products will become available for weather prediction and hydrometeorological applications.
Meridional wind effect on anti‐solar activity correlation of equatorial density irregularity distribution
Authors: Su S.‐Y. , Chao C. K. , Liu C. H. , Ho H. H.
Published: October 2007

Contrasting longitudinal variation in equatorial spread‐F (ESF) density irregularity distribution has been observed by ROCSAT‐1 during high solar activity year of 2000 against moderate solar activity year of 2003. The monthly averaged solar flux intensity F10.7 was higher every month in 2000 than in 2003, but the irregularity occurrence rate did not always correlate with solar activity at every longitude in a season. For the equinox seasons, the occurrence rate was higher at every longitude in 2000 than in 2003. Higher occurrence rate was also observed in 2000 than in 2003 during a solstice season at longitudes of the so‐called ESF longitudes. On the other hand, higher occurrence rates were observed in 2003 at the so‐called low‐ESF longitudes from 230° to 10° during the June solstice season and from 90° to 260° during the December solstice season, where the magnetic flux tube makes a large‐angle alignment with the sunset terminator during the respective solstice season. Such anti‐solar activity correlation of ESF irregularity occurrences at these low‐ESF longitudes could be due to transequatorial meridional wind‐induced instability suppression agent which becomes more effective to offset the Rayleigh‐Taylor instability growth rate in a solstice season during a high solar activity period than during a low solar activity period.
Equatorial Ionospheric Electric Fields During the November 2004 Magnetic Storm
Authors: Fejer B. G. , Jensen J. W. , Kikuchi T. , Abdu M. A. , Chau J. L.
Published: October 2007

We use radar measurements from the Jicamarca Radio Observatory, magnetometer observations from the Pacific sector and ionosonde data from Brazil to study equatorial ionospheric electric fields during the November 2004 geomagnetic storm. Our data show very large eastward and westward daytime electrojet current perturbations with lifetimes of about an hour (indicative of undershielding and overshielding prompt penetration electric fields) in the Pacific equatorial region during the November 7 main phase of the storm, when the southward IMF, the solar wind and reconnection electric fields, and the polar cap potential drops had very large and nearly steady values. This result is inconsistent with the recent suggestion that solar wind electric fields penetrate without attenuation into the equatorial ionosphere for several hours during storm main phase. The largest daytime prompt penetration electric fields (about 3 mV/m) ever observed over Jicamarca occurred during the November 9 storm main phase, when large equatorial electrojet current and drift perturbations were also present in the Pacific and Brazilian equatorial regions. The rise and decay times of these equatorial electric fields were about 20 min longer than of the corresponding solar wind electric fields. The ratios of prompt penetration electric fields and corresponding solar wind electric field changes were highly variable even during the day, and had largest values near dawn. Also, the prompt penetration electric fields did not show polar cap potential drop saturation effects. Our results clearly highlight that the relationships of prompt penetration and solar wind electric fields, and polar cap potentials are far more complex than implied by simple proportionality factors.
Seismic scaling relations and aftershock activity from the sequences of the 2004 mid Niigata and the 2005 west off Fukuoka earthquakes (MW 6.6) in Japan
Authors: Tajima Reiko , Tajima Fumiko
Published: October 2007

We investigate seismic scaling relations and seismic activity using two Japanese earthquake sequences, the 2004 mid Niigata prefecture earthquake (MNPE) and the 2005 west off Fukuoka prefecture earthquake (WOFE) sequences. Although the mainshocks of the two sequences have the same MW of 6.6, the aftershock activities are different from each other in term of moment release. The MNPE produced a large number of aftershocks including six events with MW ≥ 5.5 over a period of about two weeks. On the other hand, the WOFE sequence did not produce aftershocks that exceeded MW 5.5. In the scaling relationship of seismic moment (M0) versus corner frequency (fc) obtained from the MNPE sequence, the fc's tend to decrease with decreasing M0 between MW 3.5 and 6.6 and the best fit line determined in a least squares sense is M0 ∝ fc−3.41. In the WOFE sequence, the best fit line is M0 ∝ fc−3.06 in the same MW range. The fc range of small aftershocks is lower in the MNPE sequence than in the WOFE sequence. Moreover, the M0 − fc relations for small events (3.5 ≤ MW ≤ 4.0) in the MNPE sequence are different between the events on the main faults (M0 ∝ fc−3.53) and the off‐main fault events (M0 ∝ fc−4.44). These results suggest that there is difference (or variation) in the scaling relation even in the same MW range, probably reflecting different tectonic or seismogenic conditions.
Imaging mantle discontinuities using least squares Radon transform
Authors: An Yuling , Gu Yu Jeffrey , Sacchi Mauricio D.
Published: October 2007

Differential traveltimes of SS precursors have been widely used to map large‐scale mantle structure and depths of discontinuities. Measurements are commonly made by stacking individual records to increase the signal‐to‐noise ratio pertaining to these mild reflections. However, ray parameters of the SS precursors are typically less well constrained and undesired seismic arrivals with vastly different slownesses (for example, scattered waves) could potentially contaminate the time domain stacks. To overcome these pitfalls, we introduce a processing scheme based on the Radon transform and well‐constrained inversions. Our method is particularly effective in suppressing background noise, constraining differential ray parameter and traveltime, and detecting weak reflected or converted phases. We apply the Radon‐based method to delineate the discontinuity structure beneath the northeastern Pacific Ocean and the northwestern Canada. An elevated 410‐km discontinuity and a thickened transition zone (252 km) are observed beneath the northern British Columbia, which may be caused by remnant oceanic lithosphere from the subduction of Kula‐Farallon plate under North America. A thin transition zone is identified beneath the northern Pacific Ocean and its presence is supported by a low shear‐velocity anomaly from recent tomographic models. The improved accuracy and resolution using the least squares Radon transform also offer clear evidence for a regional 520‐km discontinuity and several mild reflectors in the depth ranges of 250–330 km and 900–1200 km. We do not observe a 220‐km discontinuity beneath the study region.
The relationship between the occurrence rate of major stratospheric warmings and solar Lyman‐alpha flux
Authors: Sonnemann G. R. , Grygalashvyly M.
Published: October 2007

The statistical connection between major sudden stratospheric warmings (MSSWs) and solar activity was investigated using the Lyman‐alpha flux as a proxy. We subdivided the considered time period between winter 1950‐51 and winter 2006‐07, for which data about MSSWs is available in discrete time intervals of 4 months, and determined the mean Lyman‐alpha flux in them. For the statistical analysis, only those months between December and March, when MSSWs exclusively occurred, were used. Then the range of values of the Lyman‐alpha flux was subdivided into discrete bins of 0.25 × 1011 photons/cm2 s. Next we determined the frequency at which the mean flux values from the chosen months belonged to the subdivided flux intervals. After that we assigned the number of MSSW occurred under the conditions of a certain Lyman‐alpha flux value to the corresponding frequency of the flux values. Finally, we correlated the related MSSW occurrence rate with the discrete Lyman‐alpha flux values. The analysis revealed a significant positive correlation between the 11‐years solar activity and the occurrence rate of the related MSSWs.
Climate response to projected changes in short‐lived species under an A1B scenario from 2000–2050 in the GISS climate model
Authors: Shindell Drew T. , Faluvegi Greg , Bauer Susanne E. , Koch Dorothy M. , Unger Nadine , Menon Surabi , Miller Ron L. , Schmidt Gavin A. , Streets David G.
Published: October 2007

We investigate the climate forcing from and response to projected changes in short‐lived species and methane under an A1B scenario from 2000‐2050 in the GISS climate model. We present a meta‐analysis of new simulations of the full evolution of gas and aerosol species and other existing experiments with variations of the same model. The comparison highlights the importance of several physical processes in determining radiative forcing, especially the effect of climate change on stratosphere‐troposphere exchange, heterogeneous sulfate‐nitrate‐dust chemistry, and changes in methane oxidation and natural emissions. However, the impact of these fairly uncertain physical effects is substantially less than the difference between alternative emission scenarios for all short‐lived species. The net global mean annual average direct radiative forcing from the short‐lived species is .02 W/m2 or less in our projections, as substantial positive ozone forcing is largely offset by negative aerosol direct forcing. Since aerosol reductions also lead to a reduced indirect effect, the global mean surface temperature warms by ∼0.07°C by 2030 and ∼0.13°C by 2050, adding 19% and 17%, respectively, to the warming induced by long‐lived greenhouse gases. Regional direct forcings are large, up to 3.8 W/m2. The ensemble‐mean climate response shows little regional correlation with the spatial pattern of the forcing, however, suggesting that oceanic and atmospheric mixing generally overwhelms the effect of even large localized forcings. Exceptions are the polar regions, where ozone and aerosols may induce substantial seasonal climate changes.
Cardiovascular effects of a novel potent and highly selective azaindole‐based inhibitor of Rho‐kinase
Authors: Kast R , Schirok H , Figueroa‐Pérez S , Mittendorf J , Gnoth M J , Apeler H , Lenz J , Franz J K , Knorr A , Hütter J , Lobell M , Zimmermann K , Münter K , Augstein K H , Ehmke H , Stasch J P
Published: October 2007

Background and purpose:

Rho‐kinase (ROCK) has been implicated in the pathophysiology of altered vasoregulation leading to hypertension. Here we describe the pharmacological characterization of a potent, highly selective and orally active ROCK inhibitor, the derivative of a class of azaindoles, azaindole 1(6‐chloro‐N

4‐{3,5‐difluoro‐4‐[(3‐methyl‐1H‐pyrrolo[2,3‐b]pyridin‐4‐yl)oxy]‐phenyl}pyrimidine‐2,4‐diamine).

Experimental approach:

Pharmacological characterization of azaindole 1was performed with human recombinant ROCK in vitro. Vasodilator activity was determined using isolated vessels in vitro and different animal models in vivo.

Key results:

This compound inhibited the ROCK‐1 and ROCK‐2 isoenzymes with IC50 s of 0.6 and 1.1 nM in an ATP‐competitive manner. Although ATP‐competitive, azaindole 1was inactive against 89 kinases (IC50>10 μM) and showed only weak activity against an additional 21 different kinases (IC50=1 ‐ 10 μM). Only the kinases TRK und FLT3 were inhibited by azaindole 1in the sub‐micromolar range, albeit with IC50 values of 252 and 303 nM, respectively. In vivo, azaindole 1lowered blood pressure dose‐dependently after i.v. administration in anaesthetized normotensive rats. In conscious normotensive and spontaneously hypertensive rats azaindole 1induced a dose‐dependent decrease in blood pressure after oral administration without inducing a significant reflex increase in heart rate. In anaesthetized dogs, azaindole 1induced vasodilatation with a moderately elevated heart rate.

Conclusions and implications:

Azaindole 1is representative of a new class of selective and potent ROCK inhibitors and is a valuable tool for the elucidation of the role of ROCK in the cardiovascular system.

British Journal of Pharmacology (2007) 152, 1070–1080; doi:10.1038/sj.bjp.0707484; published online 15 October 2007
Evolving mechanisms of action of alverine citrate on phasic smooth muscles
Authors: Hayase M , Hashitani H , Suzuki H , Kohri K , Brading A F
Published: October 2007

Background and purpose:

We have investigated the mechanisms underlying the paradoxical ability of the antispasmodic, alverine, to enhance spontaneous activity in smooth muscles while suppressing evoked activity.

Experimental approach:

The effects of alverine on spontaneous and induced contractile activity were examined in preliminary experiments with various smooth muscles. More detailed effects were also investigated by recording membrane potential, intracellular Ca2+ concentration ([Ca2+]i) and tension from single‐bundle detrusor smooth muscle (DSM) of the guinea‐pig urinary bladder.

Key results:

Alverine (10 μM) increased the frequency and amplitude of spontaneous action potentials, transient increases in [Ca2+]i and associated contractions. Alverine also decreased action potential rate of decay, suggesting inhibition of L‐type Ca channel inactivation. Charybdotoxin (50 nM) but neither cyclopiazonic acid (10 μM) nor Bay K 8644 (10 μM) attenuated alverine‐induced enhancement of spontaneous contractions. Alverine suppressed contractions produced by high K (40 mM) or ACh (10 μM), without affecting electrical responses and with little suppression of increases in [Ca2+]i. This feature was very similar to that of the effects of the Rho kinase inhibitor Y‐27632 (10 μM).

Conclusions and implications:

Alverine may increase Ca influx during action potentials due to inhibition of the inactivation of L‐type Ca channels, but may also suppress evoked activity by inhibiting the sensitivity of contractile proteins to Ca2+. The proportional contribution of Ca‐dependent and Ca‐independent contractions in DSM may differ between spontaneous and evoked activity, necessitating further investigations into the interactions between these pathways for assessing the therapeutic potential of alverine to treat DSM dysfunction.

British Journal of Pharmacology (2007) 152, 1228–1238; doi:10.1038/sj.bjp.0707496; published online 15 October 2007