bluuebunny/crossref_metadata_2025 huggingface dataset:
On the flow of buoyant fluid injected into an aquifer with a background flow
Authors: Gunn Iain , Woods Andrew W.
Published: July 2012

We study the dispersal of a plume of incompressible buoyant fluid injected into a confined inclined aquifer in which there is a background flow. We assume that, to prevent pressure buildup in the system, there is an outflow from the aquifer, with flux equal to the injection flux, through a producing well. Using the method of characteristics, we identify that the trajectory of the plume of injected fluid depends on the magnitudes of both the injection flux ${Q}_{I} $ and the background aquifer flux ${Q}_{A} $ relative to the buoyancy-driven exchange flow of injected and original fluid within the aquifer ${Q}_{E} $, on the direction of the background aquifer flow, and on whether the producing well lies upslope or downslope from the injecting well. We find the values of the controlling parameters ${Q}_{I} / {Q}_{E} $ and ${Q}_{A} / {Q}_{E} $ for which all injected fluid flows up-dip, for which the injected fluid partitions into a component moving up-dip and a component moving down-dip, and for which all injected fluid flows down-dip. A key learning from the analysis is that there may be very different plume trajectories when a buoyant fluid is injected into a confined, inclined aquifer, and prediction of the trajectory depends on knowledge of the background flow as well as the injection rate and location of the producing wells. In the process of ${\mathrm{CO} }_{2} $ sequestration, this range of initial plume geometries can inform analysis of longer-term geological storage and assessment of the risk of activating different possible leakage pathways to the surface.
Disturbance energy transport and sound production in gaseous combustion
Authors: Brear Michael J. , Nicoud Frank , Talei Mohsen , Giauque Alexis , Hawkes Evatt R.
Published: July 2012

This paper presents an analysis of the energy transported by disturbances in gaseous combustion. It extends the previous work of Myers (J. Fluid Mech., vol. 226, 1991, 383–400) and so includes non-zero mean-flow quantities, large-amplitude disturbances, varying specific heats and chemical non-equilibrium. This extended form of Myers’ ‘disturbance energy’ then enables complete identification of the conditions under which the famous Rayleigh source term can be derived from the equations governing combusting gas motion. These are: small disturbances in an irrotational, homentropic, non-diffusive (in terms of species, momentum and energy) and stationary mean flow at chemical equilibrium. Under these assumptions, the Rayleigh source term becomes the sole source term in a conservation equation for the classical acoustic energy. It is also argued that the exact disturbance energy flux should become an acoustic energy flux in the far-field surrounding a (reacting or non-reacting) jet. In this case, the volume integral of the disturbance energy source terms are then directly related to the area-averaged far-field sound produced by the jet. This is demonstrated by closing the disturbance energy budget over a set of aeroacoustic, direct numerical simulations of a forced, low-Mach-number, laminar, premixed flame. These budgets show that several source terms are significant, including those involving the mean-flow and entropy fields. This demonstrates that the energetics of sound generation cannot be examined by considering the Rayleigh source term alone.
The mean electromotive force generated by elliptic instability
Authors: Mizerski K. A. , Bajer K. , Moffatt H. K.
Published: July 2012

The mean electromotive force (EMF) associated with exponentially growing perturbations of an Euler flow with elliptic streamlines in a rotating frame of reference is studied. We are motivated by the possibility of dynamo action triggered by tidal deformation of astrophysical objects such as accretion discs, stars or planets. Ellipticity of the flow models such tidal deformations in the simplest way. Using analytical techniques developed by Lebovitz & Zweibel (Astrophys. J., vol. 609, 2004, pp. 301–312) in the limit of small elliptic (tidal) deformations, we find the EMF associated with each resonant instability described by Mizerski & Bajer (J. Fluid Mech., vol. 632, 2009, pp. 401–430), and for arbitrary ellipticity the EMF associated with unstable horizontal modes. Mixed resonance between unstable hydrodynamic and magnetic modes and resonance between unstable and oscillatory horizontal modes both lead to a non-vanishing mean EMF which grows exponentially in time. The essential conclusion is that interactions between unstable eigenmodes with the same wave-vector $\mathbi{k}$ can lead to a non-vanishing mean EMF, without any need for viscous or magnetic dissipation. This applies generally (and not only to the elliptic instabilities considered here).
Nonlinear interaction of wind-driven oblique surface waves and parametric growth of lower frequency modes
Authors: Lee Sang Soo
Published: July 2012

Nonlinear interactions between free-surface waves of the same wave speed and wind are studied by extending the linear resonant theory of Miles (J. Fluid Mech., vol. 3, 1957, pp. 185–204). A nonlinear interaction can occur when the steepness of a primary three-dimensional wave, which propagates obliquely to the wind direction, becomes of the order of the cube of the density ratio of air to water. If a secondary wave of smaller amplitude is also an oblique wave, the nonlinear critical-layer interaction between the primary and secondary fluctuations in air generates a difference mode whose wavenumbers are equal to the differences between the primary and secondary values. In addition, the nonlinear interaction in the critical layer between the primary and difference modes induces a parametric-growth effect on the secondary surface wave, if the frequency of the primary wave is higher than that of the secondary wave. The primary wave remains linear during this ‘$2+ 1$ mode critical-layer interaction’ stage between two free-surface waves and a nonlinearly generated mode. The evolution of the secondary-wave amplitude is governed by an integro-differential equation and that of the difference mode is determined by an integral equation. Both inviscid and viscous numerical results show that the nonlinear growth rates become much larger than the linear growth rates. Effect of viscosity is shown to delay the onset of the nonlinear growth. The growth of the secondary and difference modes is more effectively enhanced when the signs of propagation angles of the primary and secondary waves are opposite than when they are equal. The $2+ 1$ mode interaction can occur when wave steepnesses are very small. The nonlinear interaction is entirely confined to a thin critical layer, and the perturbations outside the critical layer are governed by linear equations. It is shown that the initial nonlinear growth of a free-surface wave could be governed by a mode–mode interaction in air.
Nutritional intake and dietary patterns in pregnancy: a longitudinal study of women with lifetime eating disorders
Authors: Micali Nadia , Northstone Kate , Emmett Pauline , Naumann Ulrike , Treasure Janet L.
Published: July 2012

There is limited knowledge about dietary patterns and nutrient/food intake during pregnancy in women with lifetime eating disorders (ED). The objective of the present study was to determine patterns of food and nutrient intake in women with lifetime ED as part of an existing longitudinal population-based cohort: the Avon Longitudinal Study of Parents and Children. Women with singleton pregnancies and no lifetime psychiatric disorders other than ED (n 9723) were compared with women who reported lifetime (ever) ED: (anorexia nervosa (AN, n 151), bulimia nervosa (BN, n 186) or both (AN+BN, n 77)). Women reported usual food consumption using a FFQ at 32 weeks of gestation. Nutrient intakes, frequency of consumption of food groups and overall dietary patterns were examined. Women with lifetime ED were compared with control women using linear regression and logistic regression (as appropriate) after adjustment for relevant covariates, and for multiple comparisons. Women with lifetime ED scored higher on the ‘vegetarian’ dietary pattern; they had a lower intake of meat, which was compensated by a higher consumption of soya products and pulses compared with the controls. Lifetime AN increased the risk for a high ( ≥ 2500 g/week) caffeine consumption in pregnancy. No deficiencies in mineral and vitamin intake were evident across the groups, although small differences were observed in macronutrient intakes. In conclusion, despite some differences in food group consumption, women with lifetime ED had similar patterns of nutrient intake to healthy controls. Important differences in relation to meat eating and vegetarianism were highlighted, as well as high caffeine consumption. These differences might have an important impact on fetal development.
Effect of sex and gestational age on neonatal body composition
Authors: Simon Laure , Borrego Paula , Darmaun Dominique , Legrand Arnaud , Rozé Jean-Christophe , Chauty-Frondas Anne
Published: July 2012

To determine the effects of length of gestation and sex on infant body composition, air displacement plethysmography was performed in forty-six full-term neonates at 3 d of life and during the week prior to hospital discharge in 180 preterm neonates. Fat mass, as a percentage of body weight, was higher in preterm than in term infants (13·4 (sd4·2)v. 10·1 (sd3·7) %, respectively;P= 0·001). The absolute amount of fat mass did not differ between preterm and full-term newborns (323 (sd126)v. 335 (sd138) g;P= 0·58), whereas lean body mass was lower in preterm than in term infants (2055 (sd280)v. 2937 (sd259) g, respectively;P< 0·001). Among full-term infants, fat mass was higher in females than in males (11·1 (sd3·7)v. 9·0 (sd3·3) %, respectively;P= 0·047), whereas we did not observe any sex difference in preterm infants (13·5 (sd4·1)v. 13·4 (sd4·3) %;P= 0·89). Our data suggest that by the time they are discharged from hospital: (1) preterm infants have a higher percentage of body fat than term neonates and (2) this is presumably due to a lesser accretion in lean body mass in the first few weeks of extra-uterine life, particularly in boys.
Nasal sarcoidosis: a cause for a medical rhinoplasty?
Authors: van Griethuysen J , Kuchai R , Taghi A S , Saleh H A
Published: July 2012

Objective:

We report the use of triamcinolone injections to correct severe nasal deformity due to sarcoidosis, as an alternative to formal surgical rhinoplasty.

Case report:

A 30-year-old woman with a long-standing history of sarcoidosis presented to a tertiary referral rhinology clinic complaining of breathing difficulty and nasal deformity. Flexible nasoendoscopy revealed red nasal plaques typical of nasal sarcoidosis, together with significant widening of the nasal bridge. Triamcinolone, a long-acting corticosteroid, was injected both intralesionally and subcutaneously over the nasal dorsum, at zero, three and eight months, resulting in long-lasting improvement of the nasal shape.

Conclusion:

Sarcoidosis is a non-caseating, granulomatous, epithelioid inflammation. Otorhinolaryngological manifestations occur in approximately 10 per cent of patients; however, there is little published experience of nasal reconstruction in such patients. We describe a quick, simple and relatively cost-effective technique, with little or no co-morbidity, with which to improve the aesthetic and symptomatic outcomes of nasal sarcoidosis.
Cerebrospinal fluid rhinorrhoea as a complication of endoscopic endonasal reduction of blowout fractures
Authors: Lee D-G , Cho K-S , Kim H-J , Roh H-J
Published: July 2012

Background:

Unless the orbital contents are supported, the insertion of nasal packing material during endoscopic endonasal surgery may cause serious intracranial complications such as cerebrospinal fluid leakage.

Methods:

Case report and literature review.

Results:

We report a patient with iatrogenic cerebrospinal fluid rhinorrhoea caused by intracranial entry of a Silastic sheet inserted into the nasal cavity. This skull defect and the surrounding skull base were successfully reconstructed in a multilayer fashion via an endoscopic endonasal approach.

Conclusion:

This case highlights the need for caution when inserting nasal packing material. During endoscopic endonasal reduction of blowout fractures, great care must be taken to support the orbital contents, in order to avoid serious intracranial complications such as cerebrospinal fluid leakage.
Clinical feasibility of temporal bone magnetic resonance imaging as a prognostic tool in idiopathic acute facial palsy
Authors: Jun B C , Chang K H , Lee S J , Park Y S
Published: July 2012

Objective:

To assess the feasibility of temporal bone magnetic resonance imaging for evaluating the severity and prognosis of idiopathic acute facial nerve palsy.

Methods:

Forty-four patients with idiopathic acute facial nerve palsy who had undergone gadolinium-enhanced magnetic resonance imaging were selected retrospectively. The degree of radiological facial nerve enhancement was determined using quantitative analysis (with region-of-interest measurements for separate facial nerve segments) and using subjective visual analysis. The clinical severity of facial nerve palsy was then correlated with the degree of facial nerve enhancement.

Results:

The visually determined degree of facial nerve enhancement did not correlate significantly with the House–Brackmann grade at either the early or late stages (p > 0.05). Results using the region-of-interest system were similar (p > 0.05).

Conclusion:

Temporal bone magnetic resonance imaging is not essential for patients with acute facial nerve palsy.
Organised haematoma of the maxillary sinus in patients with chronic renal failure
Authors: Lee D H , Joo Y E , Lim S C
Published: July 2012

Objective:

Organised haematoma of the maxillary sinus may be present in chronic renal failure patients, because these patients are at high risk of haemorrhage.

Case reports:

We present two cases of organised haematoma of the maxillary sinus in patients with chronic renal failure.

Conclusion:

A diagnosis of organised haematoma of the maxillary sinus should be considered when a patient with a history of chronic renal failure develops unilateral, recurrent epistaxis and nasal obstruction.
Border monuments: memory, counter-memory, and (b)ordering practices along the US-Mexico border
Authors: AUCHTER JESSICA
Published: July 2012

Immigrant deaths have increased in recent years due to changes in border enforcement practices, yet less attention has been paid to the memorialisation of undocumented immigrants who die crossing the US-Mexico border. This article explores the ordering mechanisms of statecraft through an examination of how the dead bodies of undocumented migrants pose a resistance to these mechanisms. I first lay out my conception of statecraft and the bordering practices involved in this specific context, then address the memorialisation of undocumented immigrants who lost their lives crossing the border. The article embarks on a journey through anonymous desert gravesites and small desert cemeteries haunted by the spectres of immigration. It explores the contestation surrounding memorialisation of death through the monument, the narratives of anonymity surrounding the memorialisation of undocumented immigrants, and the counter-memory discourses that emerge in an effort to rewrite the meaning of these migrant deaths. These counter-memorial discourses, I argue, posit desert border monuments as a threat to statecraft because they cannot be situated within the (b)ordering mechanisms of the state.
Human rights, state wrongs, and social change: the theory and practice of emancipation
Authors: BLAKELEY RUTH
Published: July 2012

This article demonstrates the significance of human rights for challenging state violence and terrorism. It is intended to enhance understanding of the concept of emancipation. Critical Security Studies has tended to focus on the individual as the agent of her/his own liberation. Yet many victims of oppression are not able to free themselves. Drawing on historical materialism, it is argued that collective agency on behalf of the oppressed has a necessary role to play in emancipatory politics. Emancipation is contingent on the capacity of specific agents, located socially and historically, to identify practices that might bring about change, structures that might be transformed, and appropriate agents that are in the best position to facilitate such change. This article shows how such collective social action has forced a reversal of some of the Bush administration's repressive policies, and has partially succeeded in curtailing the arbitrary use of US state power. This has been achieved through the national and international human rights architecture. Therefore, Marxian claims that human rights should be eschewed are mistaken, since they fail to acknowledge the emancipatory potential of human rights, the opportunities they provide for collective social action, and the role they can play in transformative social change.
Adam Smith and ordoliberalism: on the political form of market liberty
Authors: BONEFELD WERNER
Published: July 2012

In the context of the contemporary crisis of neoliberal political economy, the politics of austerity has reasserted the liberal utility of the state as the political authority of market freedom. This article argues that economy has no independent existence, and that instead, economy is a political practice. It examines the political economy of Adam Smith and the German ordoliberal tradition to decipher the character of the political in political economy and its transformation from Smith's liberal theory into neoliberal theology. Ordoliberalism emerged in the late 1920s at a time of a manifest crisis of political economy, and its argument was fundamental for the development of the neoliberal conception that free economy is matter of strong state authority. The conclusion argues with Marx that the state is the concentrated force of free economy.
Nietzsche, Kant, the democratic state, and war
Authors: DROLET JEAN-FRANÇOIS
Published: July 2012

This article offers a reconstruction of Nietzsche's critique of Kant's scheme for perpetual peace distilled from his life-long confrontation with Kant's critical philosophy. Through this reading strategy, it sheds light on Nietzsche's controversial and yet surprisingly under-researched reflections on the problem of conflict and war in human affairs. Although Nietzsche embraced many of the basic premises of Kant's critical philosophical project, he considered the ethico-political conclusions Kant drew from these to be both irrational and nihilistic. From Nietzsche's perspective, Kant's thoughts on politics and International Relations rest on a fundamental misunderstanding of the phenomena of agency, statehood, and war that elides both the tragic relationship between politics and culture, and the violence which Nietzsche believes to be latent in all attempts at reconciling individual with collective autonomy. According to Nietzsche, Kant's influential association between liberal republicanism, freedom, and peace contributed unwittingly in ushering in the cult of the nation-state, which Nietzsche warned would engulf Europe into a wholly new kind of organised violence in the coming decades. Although clearly not without their uncritical assumptions and hubristic tendencies, Nietzsche's reflections on war and peace draw attention to some of the more insidious risks and difficulties attending liberal attempts at accommodating cosmopolitan values and principles within the framework of the modern nation state.
Global politics are domestic politics: a societal approach to divergence in the G20
Authors: SCHIRM STEFAN A.
Published: July 2012

Since 2008, the leaders of industrialised and emerging economies have engaged in steering the global economy through the G20. Divergent national positions were to be expected based upon the different stages of economic development and according to previously existing international groups. The actual controversies in the G20 did not reflect these patterns, however, but showed divergence both between industrialised countries and between emerging economies. In explaining this puzzle, I argue that the driving forces for global economic governance have ceased to be industrialised or emerging countries' alliances and levels of development. Rather, the causes for the positions of G20 members can be found in economic interests and ideas dominant in the domestic politics of countries. These societal influences shape governmental preference formation in both industrialised and emerging countries and consequently influence their behaviour in global governance. The resulting divergences weaken previously existing groups such as the G7 and the BRICs, and create a new pattern in world politics. This societal approach to explaining governmental positions in global economic governance is exemplified on the core G20 issues of stimulus/public debt and global imbalances/exchange rates.
Geographic and ecological analysis of the Bearded Wood PartridgeDendrortyx barbatus: some insights on its conservation status
Authors: MOTA-VARGAS CLAUDIO , ROJAS-SOTO OCTAVIO R. , LARA CARLOS , CASTILLO-GUEVARA CITLALLI , BALLESTEROS-BARRERA CLAUDIA
Published: July 2012

Delimiting the distribution of a species is a complex task because many determining factors are difficult to assess in the field. This is important because distribution is a key factor in the decision-making process for conservation. One example is the Bearded Wood PartridgeDendrortyx barbatus, a species endemic to the temperate forests of the Sierra Madre Oriental (SMO) mountain range in Mexico. Lack of knowledge of its distribution has generated confusion over the assignment of the correct risk category. With the aim of predicting the distribution area of the Bearded Wood Partridge and contributing to strategies for its conservation, we updated and extended the knowledge of its distribution by modelling its ecological niche using GARP and MaxEnt algorithms. We also analysed its environmental distribution using principal components analysis, and contrasted the two most important environmental variables with the species’s distribution based on vegetation type. We found that the area potentially occupied by this species covers 17,956 km2according to GARP and 12,974 km2according to MaxEnt. We suggest that there is a biogeographic barrier which limits the distribution of this species in the southern part of its range. The abiotic variables that best explain its distribution are average annual precipitation and elevation, both of which coincide well with the distribution of cloud forest. A redefinition of the current range as recognised by IUCN is proposed along with the need to change its national risk category.
Influence of selected (pre-)maturational parameters on in vitro development and sex distribution of bovine embryos
Authors: Abele Eva , Stinshoff Hanna , Hanstedt Ana , Wilkening Sandra , Meinecke-Tillmann S. , Wrenzycki Christine
Published: July 2012

The objectives of this research were to study the influence of a reduced oxygen concentration during in vitro maturation (IVM) and examine the effect of follicular glucose concentration on bovine in vitro development and sex distribution. In the first experiment, abattoir-derived cumulus–oocyte complexes (COC) were matured under 5% O2 or 20% O2. Secondly, COC were isolated and the glucose (G) concentration of each follicle was determined. COC were pooled in groups (G<1.1mMol or G≥1.1mMol) according to the glucose content before being subjected to in vitro production (IVP). Cleavage and development rates were assessed on days 3, 7 and 8 post insemination. Blastocysts of each group were sexed by polymerase chain reaction (PCR). Expanded blastocysts were stained to assess total cell numbers and live–dead cell ratio. Cleavage and development rates stayed similar after reducing the O2 concentration during IVM. The sex ratio of embryos generated from oocytes matured under 5% O2 was shifted in favour of the female (♀: 61.9%), whereas the sex ratio of embryos belonging to the IVM 20% O2 group did not differ significantly from the expected 50:50 ratio. Neither a ‘higher’ nor a ‘lower’ intrafollicular glucose concentration influenced cleavage and development rates, cell numbers or live–dead cell ratio. Eighty five per cent (G<1.1) and 63.6% (G≥1.1) of the analysed embryos were female. In summary, neither a reduced O2 concentration during IVM nor selection based on follicular glucose concentrations affected the morphological quality of embryos. Although the sex distribution was shifted in favour of female embryos in all three experimental groups, more male embryos could be seen in the G≥1.1 group compared with the G<1.1 group.
Food consumption of Sri Lankan adults: an appraisal of serving characteristics
Authors: Jayawardena Ranil , Byrne Nuala M , Soares Mario J , Katulanda Prasad , Hills Andrew P
Published: July 2012

Objective

The main aim of the present study was to identify food consumption in Sri Lankan adults based on serving characteristics.

Design

Cross-sectional study. Fruits, vegetables, starch, meat, pulses, dairy products and added sugars in the diet were assessed with portion sizes estimated using standard methods.

Setting

Twelve randomly selected clusters from the Sri Lanka Diabetes and Cardiovascular Study.

Subjects

Six hundred non-institutionalized adults.

Results

The daily intake of fruit (0·43), vegetable (1·73) and dairy (0·39) portions were well below national recommendations. Only 3·5 % of adults consumed the recommended 5 portions of fruits and vegetables/d; over a third of the population consumed no dairy products and fewer than 1 % of adults consumed 2 portions/d. In contrast, Sri Lankan adults consumed over 14 portions of starch and 3·5 portions of added sugars daily. Almost 70 % of those studied exceeded the upper limit of the recommendations for starch intake. The total daily number of meat and pulse portions was 2·78.

Conclusions

Dietary guidelines emphasize the importance of a balanced and varied diet; however, a substantial proportion of the Sri Lankan population studied failed to achieve such a recommendation. Nutrition-related diseases in the country may be closely correlated with unhealthy eating habits.
Social Policy, Cultural Integration and Faith: A Muslim Reflection
Authors: Hussain Dilwar
Published: July 2012

This article is a reflection on some of the discussions around faith and public life, within the context of Muslim communities and their interaction with public policy. It looks at the gap between popular debates on Muslims and the actual lived socio-economic reality of most people of Muslim background, and then goes on to look at aspects of identity formation and Muslim identity politics in the UK. It also considers the idea of integration and looks briefly at emerging Islamic discourses that are grappling with some of the challenges presented by modern British society. Finally, the article explores the role of faith in the public sphere and if it can help to build social capital and play a role in ideas such as the Big Society. The article concludes by emphasising the need to move beyond identity politics and communitarianism and asks where the real divides in society are – between religious and ideological groups or within them?
Schuleintritt als Risiko für Schulanfänger? 11Dieser Beitrag wurde unter der geschäftsführenden Herausgeberschaft von Jens Möller angenommen.
Authors: Faust Gabriele , Kratzmann Jens , Wehner Franziska
Published: July 2012

Zusammenfassung: Der Schuleintritt gilt als kritische Schwelle im Leben und in den Bildungskarrieren von Kindern. An Daten der BiKS-Längsschnittstudie 3–10 wurden auf der Basis von Eltern- und Lehrerangaben zu vier Messzeitpunkten jeweils neun und drei Monate vor und nach dem Schuleinstieg der Kinder (N = 554 aus 97 Kindergartengruppen in Bayern und Hessen) zwei Fragen überprüft: (1.) Werden psychosoziale Probleme im Zusammenhang mit dem Schuleintritt besser vom Transitionsansatz oder von der «paradoxen» Theorie Caspi und Moffits vorausgesagt? Mit Hilfe von Latent-Change-Modellen zeigt sich für die drei untersuchten Subskalen der Child Behavior Check List (CBCL), dass die Ausgangsmittelwerte sehr niedrig sind und sich kaum verändern. Dies spricht für bereits länger andauernde Verhaltens- und Persönlichkeitsprobleme bei den wenigen Kindern, bei denen der Übergang mit Problemen einhergeht, was die “paradoxe” Theorie Caspi und Moffitts bestätigt und möglichst frühe Interventionen in der Kindertageseinrichtung nahe legt. (2.) In einer zweiten Fragestellung wird regressionsanalytisch untersucht, inwieweit individuelle, familiäre und institutionelle Prädiktoren einen erfolgreichen Schuleintritt beeinflussen. Erwartet wird, dass Mädchen, Kinder mit besseren Vorkenntnissen und aus höher gebildeten Elternhäusern sowie ältere Kinder einen besseren Schulstart haben und dass Schulvorbereitung im Kindergarten und Kooperationsmaßnahmen von Kindergarten und Grundschule einen Schutz für Schulanfänger darstellen. Während die Hypothesen zu den individuellen Prädiktoren und zum familiären Bildungsniveau bestätigt werden, sind die institutionellen Prädiktoren weitgehend ohne Einfluss.
Erstsprachliche Leistungsentwicklung im Immersionsunterricht: Vorteile trotz Unterrichts in einer Fremdsprache?
Authors: Gebauer Sandra Kristina , Zaunbauer Anna C. M. , Möller Jens
Published: July 2012

Zusammenfassung: Immersionsunterricht stellt eine Integration von Sprach- und Fachunterricht (vgl. CLIL) dar, bei dem Schüler in einer Fremdsprache (z. B. Englisch) unterrichtet werden. In dieser Studie wurde die Entwicklung von Leseflüssigkeit und Rechtschreibleistung in den ersten vier Jahrgangsstufen von n = 351 immersiv und n = 306 konventionell unterrichteten Schülern verglichen. Latente Wachstumskurvenmodelle zeigten, dass die Schülergruppen in beiden Domänen dasselbe Ausgangsniveau aufwiesen. In der Leseflüssigkeit fand sich jedoch ein schnellerer Leistungszuwachs bei den immersiv unterrichteten Schülern, während sich die Rechtschreibleistung in beiden Gruppen ähnlich positiv entwickelte. Damit bestätigt sich, dass Immersionsschüler trotz Unterrichts in einer Fremdsprache mindestens keine Nachteile im L1-Lesen und Schreiben erleiden. Die Befunde werden in Hinblick auf positive Effekte des Immersionsunterrichts auf kognitive Funktionen und interlinguale Transferprozesse diskutiert.
Global nutrient limitation in terrestrial vegetation
Authors: Fisher Joshua B. , Badgley Grayson , Blyth Eleanor
Published: July 2012

Most vegetation is limited in productivity by nutrient availability, but the magnitude of limitation globally is not known. Nutrient limitation is directly relevant not only to ecology and agriculture, but also to the global carbon cycle by regulating how much atmospheric CO2the terrestrial biosphere can sequester. We attempt to identify total nutrient limitation in terrestrial plant productivity globally using ecophysiological theory and new developments in remote sensing for evapotranspiration and plant productivity. Our map of nutrient limitation qualitatively reproduces known regional nutrient gradients (e.g., across Amazonia), highlights differences in nutrient addition to croplands (e.g., between “developed” and “developing” countries), identifies the role of nutrients on the distribution of major biomes (e.g., tree line migration in boreal North America), and compares similarly to a ground‐based test along the Long Substrate Age Gradient in Hawaii, U.S.A. (e.g., foliar and soil nutrients, litter decomposition). Nonetheless, challenges in representing light and water use efficiencies, disturbance, and comparison to ground data with multiple interacting nutrients provide avenues for further progress on refining such a global map. Global average reduction in terrestrial plant productivity was within 16–28%, depending on treatment of disturbance; these values can be compared to global carbon cycle model estimates of carbon uptake reduction with nutrient cycle inclusion.
Analyzing the hemispheric asymmetry in the thermospheric density response to geomagnetic storms
Authors: A Ercha , Ridley Aaron J. , Zhang Donghe , Xiao Zuo
Published: July 2012

The thermospheric densities derived by CHAMP/STAR accelerometer within the time period from 01 May 2001 to 31 December 2007 are utilized to investigate the hemispheric asymmetry in response to strong storm driving conditions. The geomagnetic storms of 03–07 April 2004 are first studied since the storms occurred close to the vernal equinox, allowing the seasonal asymmetry to be eliminated to the greatest extent. The averaged density enhancements in the southern polar region were much larger than that in the northern polar region. The comparisons of density versus Dst and Apindex indicate a strong linear dependence with the slopes of the fitted lines in the southern hemisphere being 50% greater than that in the northern hemisphere. This effect can possibly be attributed to the non‐symmetric geomagnetic field. 102 storm events are used to conduct a statistical analysis. For each storm, a linear fit is made between the averaged mass density and theDst and Ap indices independently in each hemisphere. The seasonal variation of the intercepts and the slopes of the fitted lines are further explored. The baseline is strongly dependent on season, with the hemisphere receiving the larger amount of sunlight having larger density. The slopes showed considerable hemispheric differences around the vernal equinox yet no statistical differences around other seasons. It is speculated that competing mechanisms cancel each other during the solstices, while during the equinoxes, the lower magnetic field in the southern hemisphere may allow stronger ion flows, thereby causing more Joule heating. It is uncertain why the vernal equinox would be favored in this explanation though.
Time‐dependent MHD modeling of the global solar corona for year 2007: Driven by daily‐updated magnetic field synoptic data
Authors: Yang L. P. , Feng X. S. , Xiang C. Q. , Liu Yang , Zhao Xuepu , Wu S. T.
Published: July 2012

In this paper, we develop a time‐dependent MHD model driven by the daily‐updated synoptic magnetograms (MHD‐DUSM) to study the dynamic evolution of the global corona with the help of the 3D Solar‐Interplanetary (SIP) adaptive mesh refinement (AMR) space‐time conservation element and solution element (CESE) MHD model (SIP‐AMR‐CESE MHD Model). To accommodate the observations, the tangential component of the electric field at the lower boundary is specified to allow the flux evolution to match the observed changes of magnetic field. Meanwhile, the time‐dependent solar surface boundary conditions derived from the method of characteristics and the mass flux limit are incorporated to couple the observation and the 3D MHD model. The simulated evolution of the global coronal structure during 2007 is compared with solar observations and solar wind measurements from both Ulysses and spacecrafts near the Earth. The MHD‐DUSM model is also validated by comparisons with the standard potential field source surface (PFSS) model, the newly improved Wang‐Sheeley‐Arge (WSA) empirical formula, and the MHD simulation with a monthly synoptic magnetogram (MHD‐MSM). Comparisons show that the MHD‐DUSM results have good overall agreement with coronal and interplanetary structures, including the sizes and distributions of coronal holes, the positions and shapes of the streamer belts, and the transitions of the solar wind speeds and magnetic field polarities. The MHD‐DUSM results also display many features different from those of the PFSS, the WSA, and the MHD‐MSM models.
Formation of stratospheric nitric acid by a hydrated ion cluster reaction: Implications for the effect of energetic particle precipitation on the middle atmosphere
Authors: Kvissel O.‐K. , Orsolini Y. J. , Stordal F. , Isaksen I. S. A. , Santee M. L.
Published: July 2012

In order to improve our understanding of the effects of energetic particle precipitation on the middle atmosphere and in particular upon the nitrogen family and ozone, we have modeled the chemical and dynamical middle atmosphere response to the introduction of a chemical pathway that produces HNO3 by conversion of N2O5 upon hydrated water clusters H+·(H2O)n. We have used an ensemble of simulations with the National Center for Atmospheric Research (NCAR) Whole‐Atmosphere Community Climate Model (WACCM) chemistry‐climate model. The chemical pathway alters the internal partitioning of the NOy family during winter months in both hemispheres, and ultimately triggers statistically significant changes in the climatological distributions of constituents including: i) a cold season production and loss of HNO3 and N2O5, respectively, and ii) a cold season decrease and increase in NOx/NOy‐ratio and O3, respectively, in the polar regions of both hemispheres. We see an improved seasonal evolution of modeled HNO3 compared to satellite observations from Microwave Limb Sounder (MLS), albeit not enough HNO3 is produced at high altitudes. Through O3changes, both temperature and dynamics are affected, allowing for complex chemical‐dynamical feedbacks beyond the cold season when the pathway is active. Hence, we also find a NOxpolar increase in spring‐to‐summer in the southern hemisphere, and in spring in the northern hemisphere. The springtime NOxincrease arises from anomalously strong poleward transport associated with a weaker polar vortex. We argue that the weakening of zonal‐mean polar winds down to the lower stratosphere, which is statistically significant at the 0.90 level in spring months in the southern hemisphere, is caused by strengthened planetary waves induced by the middle and sub‐polar latitude zonal asymmetries in O3and short‐wave heating.
Numerical simulation of saltating particles in atmospheric boundary layer over flat bed and sand ripples
Authors: Tong Ding , Huang Ning
Published: July 2012

In this work, we numerically simulated the saltating particles in a turbulent boundary layer over flat bed and sand ripples. By using natural sand grains in a wind tunnel, we obtained the initial conditions for the simulation and also verified the correctness of the numerical model. We carefully analyzed the numerically simulated saltating particle movement over the two sand beds, and we found the following. (1) The aeolian sand transport is a dynamic equilibrium process on both sand beds, and it took longer to reach equilibration on the sand ripples than on the flat bed. (2) According to the mass flux profile at the trough of the sand ripples, there is a maximum mass flux at about 4 cm height in the leeward section. The mass flux increases with height below 4 cm and decreases with height above 4 cm. (3) The wind profile near the surface is modified by saltating particles on the two different sand beds, and the flow field characteristics of the sand ripples are more complex than that of the flat bed.
A new multiscale routing framework and its evaluation for land surface modeling applications
Authors: Wen Zhiqun , Liang Xu , Yang Shengtian
Published: July 2012

A new multiscale routing framework is developed and coupled with the Hydrologically based Three‐layer Variable Infiltration Capacity (VIC‐3L) land surface model (LSM). This new routing framework has a characteristic of reducing impacts of different scales (both in space and time) on the routing results. The new routing framework has been applied to three different river basins with six different spatial resolutions and two different temporal resolutions. Their results have also been compared to the D8‐based (eight direction based) routing scheme, whose flow network is generated from the widely used eight direction (D8) method, to evaluate the new framework's capability of reducing the impacts of spatial and temporal resolutions on the routing results. Results from the new routing framework show that they are significantly less affected by the spatial resolutions than those from the D8‐based routing scheme. Comparing the results at the basins' outlets to those obtained from the instantaneous unit hydrograph (IUH) method which has, in principle, the least spatial resolution impacts on the routing results, the new routing framework provides results similar to those by the IUH method. However, the new routing framework has an advantage over the IUH method of providing routing information within the interior locations of a basin and along the river channels, while the IUH method cannot. The new routing framework also reduces impacts of different temporal resolutions on the routing results. The problem of spiky hydrographs caused by a typical routing method, due to the impacts of different temporal resolutions, can be significantly reduced.
Application of high‐resolution, remotely sensed data for transient storage modeling parameter estimation
Authors: Bingham Q. G. , Neilson B. T. , Neale C. M. U. , Cardenas M. B.
Published: July 2012

This paper presents a method that uses high‐resolution multispectral and thermal infrared imagery from airborne remote sensing for estimating two model parameters within the two‐zone in‐stream temperature and solute (TZTS) model. Previous TZTS modeling efforts have provided accurate in‐stream temperature predictions; however, model parameter ranges resulting from the multiobjective calibrations were quite large. In addition to the data types previously required to populate and calibrate the TZTS model, high‐resolution, remotely sensed thermal infrared (TIR) and near‐infrared, red, and green (multispectral) band imagery were collected to help estimate two previously calibrated parameters: (1) average total channel width (BTOT) and (2) the fraction of the channel comprising surface transient storage zones (β). Multispectral imagery in combination with the TIR imagery provided high‐resolution estimates ofBTOT. In‐stream temperature distributions provided by the TIR imagery enabled the calculation of temperature thresholds at which main channel temperatures could be delineated from surface transient storage, permitting the estimation ofβ. It was found that an increase in the resolution and frequency at which BTOT and β were physically estimated resulted in similar objective functions in the main channel and transient storage zones, but the uncertainty associated with the estimated parameters decreased.
A slow slip event in the south central Alaska Subduction Zone and related seismicity anomaly
Authors: Wei Meng , McGuire Jeffrey J. , Richardson Eliza
Published: July 2012

We detected a slow slip event in the south central Alaska Subduction Zone by analyzing continuous GPS data from the Plate Boundary Observatory (PBO) network. The slow slip event started in early 2010 at a depth of 35 km beneath the Cook Inlet, near the down‐dip end of the locked zone, and is ongoing as of November 2011 with an accumulated magnitude ofMw 6.9. Analysis of the earthquake catalog in the same area using the stochastic Epidemic Type Aftershock Sequence model (ETAS) shows a small but detectable seismicity increase during the slow slip event. We also find a change in seismicity rate around 1998, that may suggest an earlier slow slip event in the same region. Slow slip events in Alaska appear more widespread than previously thought but have remained undetected due to their long durations, the time intervals between them, and the limited time records from the continuous GPS.
Lagrangian decomposition of the Hadley and Ferrel cells
Authors: Kjellsson J. , Döös K.
Published: July 2012

The meridional overturning circulation of the atmosphere between 45°S and 45°N is decomposed using simulated 3D Lagrangian trajectories for calculating the Lagrangian overturning streamfunctions. This permits an analysis of meridional mass transports which otherwise cancel in time‐averaged zonal‐mean Eulerian streamfunctions. Overturning circulations inferred from trajectories of no net meridional transport are qualitatively similar to the Eulerian mean, but yield half the Hadley cell amplitude, and twice that of the Ferrel cell. Cross‐equatorial transports of some 130 Sv result in two cells that account for the remainder of the Hadley cells. The overturning in midlatiudes is partly cancelled by large (>150 Sv) meridional transports approximately following isentropes. Changes and implications for various coordinate systems, e.g., isentropic, are also discussed.
Oceanic transports through the Solomon Sea: The bend of the New Guinea Coastal Undercurrent
Authors: Gasparin Florent , Ganachaud Alexandre , Maes Christophe , Marin Frédéric , Eldin Gérard
Published: July 2012

Thermocline waters of the tropical southwest Pacific can be traced back to the center of the South Pacific basin and have a potential influence on equatorial surface conditions and on the characteristics of the El Niño Southern Oscillation on decadal timescales. The Solomon Sea is traversed by this influential flow, and therefore is an optimal place for exploring this oceanic connection to the equator. From a high‐resolution hydrographic survey at which we applied an inverse box model, we describe the main pathways at the entrance of the Solomon Sea, and more particularly the extremely sharp bend of the western boundary current around the south‐east tip of Papua New Guinea. Of the 30 Sv subtropical waters transported into the Coral Sea from the east, above 1300 m, 29 ± 5 Sv makes its way through the Solomon Sea with a large part transported in a boundary current, at the entrance of the Solomon Sea. Around the south‐east tip of Papua New Guinea, the Gulf of Papua Current turns abruptly to the north, in a very sharp bend as it merges into the New Guinea Coastal Undercurrent, on its way, toward the equator. The warm currents transport large amounts of internal energy, with a total of 1.0 ± 0.3 1015W entering the Solomon Sea from the south.
Deep‐water seamount wakes on SEASAT SAR image in the Gulf Stream region
Authors: Zheng Quanan , Holt Benjamin , Li Xiaofeng , Liu Xinan , Zhao Qing , Yuan Yeli , Yang Xiaofeng
Published: July 2012

A SEASAT synthetic aperture radar (SAR) image taken over the Gulf Stream region shows streak‐like patterns. The physics of their generation and interaction with the Gulf Stream are disputed. This study seeks a convincing interpretation for the SAR imagery patterns. Bathymetric maps show that the sea floor area beneath the streaks is the northeast Hoyt Hills, where isolated seamounts with the heights of 20 to 140 m above the background sea floor are distributed. All the SAR imagery streaks originate from these seamounts and extend downstream. Thus the SAR imagery streaks are interpreted as surface roughness imprints of the seamount wakes. Hydrostatic flow dynamics of the generation of wakes on the lee side of a solid obstacle is used to explain the generation mechanism and internal structure of the seamount wakes. The analysis indicates that boundary conditions and hydrodynamic conditions are favorable for the generation and vertical propagation of the seamount wakes to the upper layer.
On the proportion of ballast versus non‐ballast associated carbon export in the surface ocean
Authors: Le Moigne Frédéric A. C. , Sanders Richard J. , Villa‐Alfageme María , Martin Adrian P. , Pabortsava Katsiaryna , Planquette Hélène , Morris Paul J. , Thomalla Sandy J.
Published: July 2012

The role of biominerals in driving carbon export from the surface ocean is unclear. We compiled surface particulate organic carbon (POC), and mineral ballast export fluxes from 55 different locations in the Atlantic and Southern Oceans. Substantial surface POC export accompanied by negligible mineral export was recorded implying that association with mineral phases is not a precondition for organic export to occur. The proportion of non‐mineral associated sinking POC ranged from 0 to 80% and was highest in areas previously shown to be dominated by diatoms. This is consistent with previous estimates showing that transfer efficiency in such regions is low. However we propose that, rather than the low transfer efficiency arising from diatom blooms being inherently characterized by poorly packaged aggregates which are efficiently exported but which disintegrate readily in mid water, it is due to such environments having very high levels of unballasted organic C export.