bluuebunny/crossref_metadata_2025 huggingface dataset:
‘Choice’: what we mean by it, and what that means for preventing childhood obesity
Authors: Porter Christine M
Published: March 2012

Objective

(i) To map how US adults value ‘choice’ in the context of obesity policy and (ii) to discuss implications for obesity prevention in children.

Design

Semi-structured interviews (n105) were conducted between 2006 and 2009 about causes of and solutions to childhood obesity. Quotes captured in field notes from community meetings (n6) on childhood obesity prevention were also analysed. Each use of the word ‘choice’ and its variants was identified in these texts. Content and discourse were analysed to identify the implied values and meaning in each use.

Setting

North-eastern USA.

Subjects

One hundred and five adults, some involved in childhood obesity prevention initiatives.

Results

Three distinct frames of ‘choice’ emerged: (i) having choices (choice as freedom), (ii) making choices (choice as responsibility) and (iii) influencing choices (contextual constraints and impacts on choice). Many speakers used more than one frame over the course of an interview. Most people using the third frame seemed to share the values behind the first two frames, but focused on conditions required to enable people to be accountable for their choices and to make truly free choices. A small subset thought outside the frame of individual choice, valuing, as one person put it, a ‘social contract’.

Conclusions

Public debate in the USA about responsibility for and solutions to rising obesity rates often hinges on notions of ‘choice’. These frames, and the values underlying them, are not mutually exclusive. Respecting the values behind each ‘choice’ frame when crafting obesity prevention policy and employing all three in public communications about such policy may facilitate greater consensus on prevention measures.
Microstructural Evaluation of Boron Free and Boron Containing Heat-Treated Ti-35Nb-7.2Zr-5.7Ta Alloy
Authors: Majumdar Pallab
Published: March 2012

The microstructure of Ti-35Nb-7.2Zr-5.7Ta (TNZT) and Ti-35Nb-7.2Zr-5.7Ta-0.5B (TNZTB) alloys under different heat treatment conditions has been analyzed. The solution-treated and water-quenched TNZT sample consists mainly of β phase with a very small amount of fine athermal ω precipitate. Precipitation of α can be observed when solution-treated samples are directly aged at 580°C for 8 h. The microstructure of the samples subjected to single-stage aging at 300°C or 400°C consists of ω precipitates in equiaxed β grains. Second stage aging at 580°C for 8 h after first stage of aging at 300°C or 400°C results in the replacement of ω precipitates by secondary α. In all of these samples, the amount of ω or α phase was very small, and therefore they could not be detected by X-ray diffraction studies. However, analysis of selected area diffraction patterns obtained from transmission electron microscopy studies confirms their presence. The addition of boron leads to the formation of dispersed precipitates of TiB in the β matrix of the TNZT alloy and also refines the β grains in the microstructure. However, other microstructural features of the TNZTB alloy are similar to those of the TNZT alloy.
Neonatal (+)-methamphetamine exposure in rats alters adult locomotor responses to dopamine D1 and D2 agonists and to a glutamate NMDA receptor antagonist, but not to serotonin agonists
Authors: Graham Devon L. , Amos-Kroohs Robyn M. , Braun Amanda A. , Grace Curtis E. , Schaefer Tori L. , Skelton Matthew R. , Williams Michael T. , Vorhees Charles V.
Published: March 2012

Neonatal exposure to (+)-methamphetamine (Meth) results in long-term behavioural abnormalities but its developmental mechanisms are unknown. In a series of experiments, rats were treated from post-natal days (PD) 11–20 (stage that approximates human development from the second to third trimester) with Meth or saline and assessed using locomotor activity as the readout following pharmacological challenge doses with dopamine, serotonin and glutamate agonists or antagonists during adulthood. Exposure to Meth early in life resulted in an exaggerated adult locomotor hyperactivity response to the dopamine D1 agonist SKF-82958 at multiple doses, a high dose only under-response activating effect of the D2 agonist quinpirole, and an exaggerated under-response to the activating effect of the N-methyl-d-aspartic acid (NMDA) receptor antagonist, MK-801. No change in locomotor response was seen following challenge with the 5-HT releaser p-chloroamphetamine or the 5-HT2/3 receptor agonist, quipazine. These are the first data to show that PD 11-20 Meth exposure induces long-lasting alterations to dopamine D1, D2 and glutamate NMDA receptor function and may suggest how developmental Meth exposure leads to many of its long-term adverse effects.
Religion and American Public Life
Authors: Elshtain Jean Bethke
Published: March 2012

In his 2000 best seller Bowling Alone: The Collapse and Revival of American Civic Community, Robert Putnam analyzed the links between social capital and civic engagement. Lamenting the decline of “civic America,” he called for a Tocquevillean renewal of voluntary association in the United States. In American Grace, Putnam and coauthor David Campbell—who also helped with the preparation of Bowling Alone—return to the analysis of American civil society, focusing their attention on America's changing religious landscape and its implications for democracy. Their basic argument is that while the United States is religiously diverse and pluralistic to a profound degree, and while in recent years it has witnessed growing religious polarization, it has also succeeded in muting religious tensions and hostilities. As they conclude: “How has America solved the puzzle of religious pluralism—the coexistence of religious diversity and devotion? And how has it done so in the wake of growing religious polarization? By creating a web of interlocking personal relationships among people of many different faiths. This is America's grace” (p. 550).

Given the importance of religion in American life and the influence of Putnam's broad agenda on much current social science research on social capital and civic engagement, we have decided to organize a symposium around the book, centered on three questions: 1) How is American Grace related to Putnam's earlier work, particularly Bowling Alone, and what are the implications of the continuities and/or discontinuities between these works? 2) What kind of a work of political science is American Grace, and how does it compare to other important recent work dealing with religion and politics in the United States? 3) What are the strengths and weaknesses of Putnam and Campbell's account of “how religion divides and unites us,” and what is the best way of thinking about the contemporary significance of religion and politics in the United States and about the ways that the religious landscape challenges U.S. politics and U.S. political science?
Occupations, Preoccupations, and Political Science
Authors: Isaac Jeffrey C.
Published: March 2012

In recent issues of Perspectives, we have sought to highlight the themes of inequality, exclusion, and the challenges facing democratic politics. We have done this because these themes resound throughout the current political world. Economist and Nobel laureate Joseph Stiglitz nicely summed up this state of affairs in a November 4, 2011 column circulated by Project Syndicate: “The protest movement that began in Tunisia in January, subsequently spreading to Egypt, and then to Spain, has now become global, with the protests engulfing Wall Street and cities across America. Globalization and modern technology now enable social movements to transcend borders as rapidly as ideas can. And social protest has found fertile ground everywhere: a sense that the ‘system’ has failed, and the conviction that even in a democracy, the electoral process will not set things right—at least not without strong pressure from the street.” The Occupy movement that spread like wildfire throughout the US, and that asserted itself on some major US university campuses, is simply the latest iteration of this diffusion of protest in which young people from Athens and Madrid to Cairo and Damascus seem to be playing a crucial role.
Response to Terrence Chapman's review of Paying Attention to Foreign Affairs: How Public Opinion Affects Presidential Decision Making.
Authors: Knecht Thomas
Published: March 2012

I want to thank Terrence Chapman for his insightful comments. The core of our respective arguments is similar: We both find that public opinion can shape international affairs in important, and perhaps unexpected, ways. Nevertheless, he offers some constructive criticism that has prompted me to think more deeply about my work.
Person-centred medicine and mental health
Authors: Salvador-Carulla L. , Mezzich J. E.
Published: March 2012

This paper discusses an integrated approach to person-centred medicine and its role in the future of mental health care. The origins and current status of this emerging field are revised with special attention to the contributions made from psychiatry and to the implications for psychiatric diagnosis and evaluation of the three pillars of the Person-centred Integrative Diagnosis (PID) model: its conceptual domains (health status, experiences and contributors to ill and good health), the related evaluative procedures, the partnerships needed and the existing links and differences with people-centred care and personalised medicine. In spite of their striking complementarities person-centred medicine and personalised medicine do not yet have substantial bridges built between them. Knowledge transfer and coordination should be established between these two models which will cast medical evaluation and care in the upcoming future.
People-centred care: new research needs and methods in doctor–patient communication. Challenges in mental health
Authors: Del Piccolo L. , Goss C.
Published: March 2012

Communication in psychiatry is nowadays called to create bridges between different levels of observation (biological, functional and relational levels) and therapeutic intervention (social and educational) with important implications for therapeutic practice and communication research in the mental health context. New research challenges and windows of opportunity for therapeutic practice will be addressed in this contribution, as they relate to the three main tasks that psychiatrists have to meet when talking with their patients: understanding patient's problems and concerns; establishing the therapeutic alliance by acknowledging and responding to patient's emotion; informing and involving patients and their families, when appropriate. Therapeutic decisions need the elaboration of valid strategies of shared decision-making, which still have to be implemented and adapted to psychiatric context. Moreover, in the research field, emerging biomarker research may contribute to better explain what makes the difference in an empathic relationship either in terms of psycho-physiological reactions and in brain changes. Finally, the influence of new technologies and of Internet has to be more and more considered during clinical consultations.
Hausaufgaben in der Psychotherapie
Authors: Helbig-Lang Sylvia , Petermann Franz
Published: March 2012

Zusammenfassung.Obwohl der Einsatz therapeutischer Hausaufgaben als Standardintervention in der Psychotherapie gilt und empirisch als wirksam belegt ist, erhalten Hausaufgaben bis heute sowohl von forschungstheoretischer als auch von praktischer Seite vergleichsweise wenig Aufmerksamkeit. So fehlen systematische Informationen darüber, welche Arten von Aufgaben und welche speziellen Strategien der Aufgabenvereinbarung zur Aufgabenerledigung durch den Patienten und damit zum Therapieerfolg beitragen. Das vorliegende Themenheft umfasst aktuelle Arbeiten zum gewinnbringenden Einsatz von Hausaufgaben in der Psychotherapie allgemein sowie in den speziellen Anwendungsbereichen der Kinder- und der Paartherapie. Dabei steht insbesondere die Ableitung von Empfehlungen für den praktischen Umgang mit Hausaufgaben im Fokus.
Hausaufgaben in der Kinderpsychotherapie
Authors: Petermann Ulrike , Petermann Franz , Röll Judith
Published: March 2012

Zusammenfassung.Hausaufgabenvereinbarungen stellen eine entscheidende Komponente in verschiedenen Psychotherapie-Ansätzen dar. Die Vergabe therapeutischer Aufgaben und deren Durchführung im Alltag beeinflussen den Therapieerfolg positiv. Es existieren zum Teil empirisch fundierte oder auf Erfahrung basierende Richtlinien zur Gestaltung und Entwicklung, Vergabe sowie Nachbesprechung derartiger Aufgaben. Entscheidend für einen positiven Nutzen der Hausaufgaben ist neben diesen Merkmalen die Akzeptanz und Bereitschaft der Patienten, diese zwischen den Therapiesitzungen zu erledigen. Oftmals mangelt es an einem systematischen Einsatz von Hausaufgaben in der Kinderpsychotherapie; darüber hinaus sind Kinder selten an Hausaufgaben interessiert, selbst wenn sie in keinem schulischen Kontext stehen, sodass sich spezifische Motivationsprobleme daraus ergeben. Aufgrund der geringen empirischen Befunde ist wenig über ein optimales therapeutisches Vorgehen zur Förderung dieser positiven Effekte bekannt. Darüber hinaus beschränken sich die Befunde und Überlegungen oft auf Psychotherapie im Erwachsenenalter. Doch auch in der Therapie mit Kindern und Jugendlichen scheint diese Form der Intervention erfolgversprechend. Es wird der bisherige Erkenntnisstand im Hinblick auf wesentliche Merkmale, Funktion und Nutzen von Hausaufgaben und den Prozess, der damit einhergeht, erläutert.
Hausaufgaben in der Psychotherapie: Was Therapeuten bei der Gestaltung beachten sollten
Authors: Breil Janine
Published: March 2012

Zusammenfassung.Hausaufgaben werden von einer Vielzahl von Therapeuten aus unterschiedlichen Therapierichtungen bei verschiedenen psychischen Störungen eingesetzt und die Vergabe von Hausaufgaben und ihre Durchführung hängen positiv mit dem Therapieerfolg zusammen. Trotzdem beruhen die Empfehlungen, die bislang zur optimalen Gestaltung von Hausaufgaben gemacht werden, vor allem auf klinischer Erfahrung und sind nicht empirisch untersucht. Mit der vorgestellten Studie soll ein erster Schritt gemacht werden, diese Lücke zu schließen. Untersucht wurden die Therapien von 303 Patienten, die von 31 Therapeuten behandelt wurden. Sowohl Therapeuten als auch Patienten beantworteten nach jeder Therapiesitzung Fragen zu den zur nächsten Sitzung vereinbarten Hausaufgaben und zur Vollständigkeit ihrer Durchführung. In schrittweisen, multiplen Regressionsanalysen zeigte sich, dass die Hausaufgabenmerkmale Zeitaufwand und Konkretheit für die Vollständigkeit der Durchführung nicht relevant sind, dass ein negativer Zusammenhang zwischen Schwierigkeit und Vollständigkeit und dass ein positiver Zusammenhang zwischen der Verbindlichkeit der Aufgabenformulierung sowie der Motivation auf der einen Seite und der Vollständigkeit auf der anderen Seite besteht.
Linkages among interannual variations of shoreline, wave and climate at Hasaki, Japan
Authors: Kuriyama Y. , Banno M. , Suzuki T.
Published: March 2012

The interannual shoreline variation during a 22‐year period from 1987 to 2008 at the Hasaki coast located in eastern Japan was found to be induced by the fluctuation of the deep water wave energy flux using an empirical shoreline prediction model. The correlation coefficients between the deep water wave energy flux and climate indices showed that the wave energy flux has a positive correlation with the Arctic Oscillation (AO) index during the period from January to April, and negative correlations with the Nino‐West Sea Surface Temperature (SST) anomaly and the Southern Oscillation Index (SOI) during the period from September to December. The shoreline prediction model using the correlations between the wave energy flux and climate indices indicated that the large‐scale variations in climate represented by the AO index, the SOI, and the Nino‐West SST anomaly accounted for 45% of the interannual shoreline variation.
Evidence of a partitioned dynamo reversal process from paleomagnetic recordings in Tahitian lavas
Authors: Hoffman Kenneth A. , Mochizuki Nobutatsu
Published: March 2012

Lavas erupted at the Society hotspot during the Matuyama‐Brunhes (M‐B) polarity reversal record transitional field behavior containing two tight paleodirectional groups that when averaged are antipodal at the 95% confidence level, and thus correlate to antipodal clustered virtual geomagnetic poles (VGPs). The occurrence of these observations––data obtained from two published records of the M‐B transition from distinct sections of a succession of flows on Tahiti––is associated with a time when the strength of the axial dipole was significantly reduced. One of the clusters was recorded by lavas that were not erupted in succession, suggesting that significant time had passed during this volcanic activity. Time spent during the formation of the antipodal cluster is unknown, although it resides in the same location as VGP clusters associated with four other transitional events obtained from Society hotspot lavas. Calculated VGPs at the Society hotspot for both “polarities” of the averaged historic field––less the axial dipole term––are found in the cluster locations. These findings offer strong evidence for a two‐tiered dynamo process in which nearly the entire axial dipole component undergoes both demise and regeneration quasi‐independently from that of the remainder of the field, the pattern of which is tied to long‐held physical conditions of the lower‐most mantle.
Atypical nighttime spread‐F structure observed near the southern crest of the ionospheric equatorial ionization anomaly
Authors: Fagundes P. R. , Bittencourt J. A. , de Abreu A. J. , Moor L. P. , Muella M. T. A. H. , Sahai Y. , Abalde J. R. , Pezzopane M. , Sobral J. H. A. , Abdu M. A. , Pimenta A. A. , Amorim D. C. M.
Published: March 2012

An atypical nighttime spread‐F structure is observed on ionograms at or above the F2 trace, near the crest of the ionospheric equatorial ionization anomaly (EIA) region. This ionospheric atypical spread‐F phenomenon was observed using two closed spaced (∼115 km) ionospheric soundings stations located in Sao Jose dos Campos (23.21°S, 45.97°W) and Cachoeira Paulista (22.70°S, 45.01°W), Brazil, in a low‐latitude station (near the southern crest of the EIA region), during nighttime, low solar activity, and quiet geomagnetic conditions. This structure, in the initial phase, appears in the ionogram as a faint spread‐F trace above or at the F2‐layer peak height. After a few minutes, it develops into a strong spread‐F trace, and afterwards, it moves to altitudes below the F2‐layer peak heights. Finally, the atypical nighttime F‐layer trace structure may remain for a while between the F‐layer bottom side and peak height or can move to an altitude above the F‐layer peak height, and then it disappears. In order to have a comprehensive view of the ionospheric environment characterizing the phenomenon under study, complementary data from six GPS station were used to investigate the ionosphere environment conditions, during both events. The six GPS stations used in this study are distributed from near the equatorial region to low latitudes and provide evidence that the atypical nighttime spread‐F structures are not related with large scale equatorial irregularities (plasma bubbles).
Equatorial longitude and local time variations of topside magnetic field‐aligned ion drifts at solar minimum
Authors: Burrell A. G. , Heelis R. A. , Stoneback R. A.
Published: March 2012

In the topside ionosphere, the high mobility of the plasma along the magnetic field allows field‐aligned ion drifts to occur readily as a result of field‐aligned gravitational forces, collisional forces, or pressure gradients. Therefore, variations in the field‐aligned ion drifts can be used to explore the influence of thermospheric, electrodynamic, and chemical processes on the ionosphere. Longitude and local time variations in the field‐aligned ion drifts near the magnetic equator are presented using observations from the Coupled Ion Neutral Dynamics Investigation on board the Communications/Navigation Outage Forecast System satellite. These observations were obtained during the period of extremely low solar activity present in 2008 and 2009, allowing the seasonal, local time, and longitudinal variations to reveal the relative importance of the processes responsible for topside field‐aligned plasma drifts during solar minimum. This investigation found that the low‐altitude winds and tides, the net ionization or loss, and the meridional E×B drift were all influential in creating longitudinal and local time variations in the field‐aligned drift, though the strength of the influence seen by each driver was found to vary with season, local time, and longitude.
Thin current sheets in the presence of a guiding magnetic field in Earth's magnetosphere
Authors: Malova H. V. , Popov V. Y. , Mingalev O. V. , Mingalev I. V. , Mel'nik M. N. , Artemyev A. V. , Petrukovich A. A. , Delcourt D. C. , Shen C. , Zelenyi L. M.
Published: March 2012

A self‐consistent theory of relatively thin anisotropic current sheets (TCS) in collisionless plasma is developed, taking into account the presence of a guiding field By (all notations are used in the GSM coordinate system). TCS configurations with a finite value of guiding field By are often observed in Earth's magnetotail and are typical for Earth's magnetopause. A characteristic signature of such configurations is the existence of a magnetic field component along the direction of TCS current. A general case is considered in this paper with global sheared magnetic field By = const. Analytical and numerical (particle‐in‐cell) models for such plasma equilibria are analyzed and compared with each other as well as with Cluster observations. It is shown that, in contrast to the case with By = 0, the character of “particle‐current sheet” interaction is drastically changed in the case of a global magnetic shear. Specifically, serpentine‐like parts of ion trajectories in the neutral plane become more tortuous, leading to a thicker current sheet. The reflection coefficient of particles coming from northern and southern sources also becomes asymmetric and depends upon the value of the By component. As a result, the degree of asymmetry of magnetic field, plasma, and current density profiles appears characteristic of current sheets with a constant By. In addition, in the presence of nonzero guiding field, the curvature current of electrons in the center of the current sheet decreases, yielding an effective thickening of the sheet. Implications of these results for current sheets in Earth's magnetosphere are discussed.
Robust determination of earthquake source parameters and mantle attenuation
Authors: Ko Yen‐Ting , Kuo Ban‐Yuan , Hung Shu‐Huei
Published: March 2012

An improved inversion technique is needed to effectively separate the frequency dependence of the source from the intrinsic attenuation of the medium. We developed a cluster‐event method (CEM) in which clusters of nearby events, instead of individual events, pair with stations to form the basis for measurements ofQ value and corner frequency (fc). We assume that the raypaths from one cluster to a station share an identical Q while each event in the same cluster is allowed for only one fcin the inversion process. This approach largely reduces the degrees of freedom to achieve a robust inversion. We use an optimization algorithm of simulated annealing to solve the nonlinear inverse problem. The CEM was applied to events at 70–150 km depths in the Japan subduction zone recorded by F‐net. We show that the method proposed here leads to better constraints on both source parameters and attenuation. The resultantQ's in the mantle wedge increase from lower than 300 beneath the arc and back‐arc to greater than 600 in the fore‐arc region. Thefc's satisfy a self‐similar scaling relationship with seismic moment ofM0 ∝ fc−3 with a best fit stress drop of 21.9 ± 6.9 MPa in Madariaga's form. This contrasts to the stress drop of 1.4 ± 1.1 MPa for a global data set composed of prior measurements for crustal events. The results of this study agree with results from previous studies, except with an upward deviation due to higher corner frequencies and stress drops.
The 3D numerical modeling of subduction dynamics: Plate stagnation and segmentation, and crustal advection in the wet mantle transition zone
Authors: Yoshida Masaki , Tajima Fumiko , Honda Satoru , Morishige Manabu
Published: March 2012

Water content in the mantle transition zone (MTZ) has been broadly debated in the Earth science community as a key issue for plate dynamics. In this study, a systematic series of three‐dimensional (3D) numerical simulation are performed in an attempt to verify a hypothesis regarding the behavior of subducted oceanic plate and the role of crust in the MTZ under wet conditions. This hypothesis is based on the seismic observations of structural variations associated with large‐scale flattened high velocity anomalies (i.e., stagnant slabs) in the MTZ. In our model, weak (low‐viscosity) fault zones (WFZs), which presumably correspond to the fault boundaries of large subduction earthquakes, are imposed on the top part of subducting plates. The phase transitions of olivine to wadsleyite and ringwoodite to perovskite+magnesiowüstite under both “dry” and “wet” conditions are considered based on recent high pressure experiments. The effect of viscosity reduction of wet garnet is also considered for oceanic crust in the MTZ. Results show that there is a substantial difference in the behaviors of subducting plate and the trace of crustal materials between the models under dry and wet conditions. Under wet conditions the subducting plate tends to stagnate with a maximum lateral extent of over 1000 km. The weaker and denser crustal material (garnet rich) is fed into the WFZs and is advected faster than the plate main body of peridotite (olivine rich). Thus, the viscosity and density contrast between the crustal materials and the peridotite permits the plate segmentation under a wet MTZ condition.
Seismic characterization of hydrates in faulted, fine‐grained sediments of Krishna‐Godavari basin: Unified imaging
Authors: Jaiswal P. , Dewangan P. , Ramprasad T. , Zelt C. A.
Published: March 2012

A combination of diffusion and advection in fine grained sediments can create a patchy Bottom Simulating Reflector (BSR) which has little to no apparent correlation with the overlying hydrate distribution. Using 2D seismic data from faulted, clay‐rich sediments in the Krishna‐Godavari (KG) basin, we show both the hydrate distribution and the BSR structure are fault controlled. Our demonstration hinges upon a kinematically accurate P wave velocity (VP) model which is estimated using a composite traveltime‐inversion, depth‐migration method in an iterative manner. The flexibility of the method allows simultaneous usage of traveltimes from multiple, discontinuous reflectors. The application begins with a simple VP model from time processing which is reflective of a diffusive, continuous, hydrate– and free gas–bearing system. The application converges in three iterations yielding a final VPmodel which is suggestive of a patchy distribution of hydrates and free gas possibly developing through a combined diffusive‐advective system. The depth image corresponding to the final VP model can be interpreted for faults that suggest ongoing tectonism. The BSR appears to be truncated at active faults zones. Both the final VP model and the corresponding depth image can be reconciled with the hydrate distribution and BSR depth at logging/coring sites located ∼250 m away from the line by projecting the sites along the strike direction of the regional faults.
Aerosol impact on the brightening in Japan
Authors: Kudo Rei , Uchiyama Akihiro , Ijima Osamu , Ohkawara Nozomu , Ohta Sachio
Published: March 2012

The long‐term changes in aerosol optical depth (AOD) and single scattering albedo (SSA) at 0.75 μm from the 1970s to the 2000s at 14 sites in Japan were estimated from the direct and diffuse irradiances measured by ground‐based broadband radiometers under clear‐sky conditions. Noticeable changes in AOD and SSA were seen: AOD decreased by 0.02, and SSA increased by 0.21. The ratio of surface solar irradiance to solar irradiance at the top of the atmosphere under clear‐sky conditions, calculated from the estimated AOD and SSA, showed apparent brightening of +0.05, of which +0.01 was attributed to a decrease of AOD and +0.04 to an increase of SSA. The cloud forcing of the surface solar irradiance, estimated as the difference between the surface solar irradiance measured under cloudy‐sky conditions and that under clear‐sky conditions, showed no significant trend. These findings suggest that the brightening in Japan has been caused by changes in aerosol optical properties, especially SSA, rather than by cloud changes.
The formation of Valles Marineris: 2. Stress focusing along the buried dichotomy boundary
Authors: Andrews‐Hanna Jeffrey C.
Published: March 2012

Although Valles Marineris is widely regarded as an extensional tectonic feature, the source of stress responsible for its formation remains unknown. This study argues that the tensile stresses that triggered Valles Marineris tectonism are a result of its location south of and subparallel to the buried crustal dichotomy boundary beneath Tharsis. The emplacement of the Tharsis volcanic load straddling the pre‐existing topographic step of the crustal dichotomy boundary would have resulted in an abrupt change in the thickness of the load, causing differential subsidence and extension across the boundary. Thin‐shell flexural models predict a narrow belt of focused tensile stresses south of the buried dichotomy boundary, coinciding with the location of present‐day Valles Marineris. The interaction of these boundary‐generated stresses with the competing stress fields associated with Tharsis loading can explain the formation of Noctis Labyrinthus in the west, and the deflection of the Valles Marineris troughs away from the buried boundary toward the east. Finite element models demonstrate that the magnitudes and vertical variations of stress at Valles Marineris are sensitive to the timing of loading and flexure in Tharsis. The incremental loading and flexure expected for a large volcanic rise results in the maximum tensile stress at Valles Marineris occurring at depth, with tensile stresses through the majority of the lithospheric column. Dikes forming within this tensile stress belt would propagate through the full vertical extent of the lithosphere due to the stress release associated with the dilation of the dikes, playing a crucial role in the formation of the Valles Marineris troughs.
Modeling methane emissions from the Alaskan Yukon River basin, 1986–2005, by coupling a large‐scale hydrological model and a process‐based methane model
Authors: Lu Xiaoliang , Zhuang Qianlai
Published: March 2012

Much progress has been made in methane modeling for the Arctic. However, there is still large uncertainty in emissions estimates due to the spatial variability in water table depth resulting from complex topographic gradients, and due to variations in methane production and oxidation due to complex freezing and thawing processes. Here we extended an extant methane emission module within a biogeochemistry model, the Terrestrial Ecosystem Model (TEM), to include a large‐scale hydrology model, the variable infiltration capacity (VIC) model. The VIC model provides the required inputs, including freezing and thawing fronts, soil temperature and moisture, to the methane module. The effect of topography on the redistribution of soil moisture and water table depth was explicitly modeled using the TOPMODEL approach. The coupled modeling framework was applied to the Yukon River basin at a spatial resolution of 1 km from 1986 to 2005. The simulations show that the average annual net emissions of CH4 from the region are 4.01 Tg CH4 yr−1. El Niño phenomena usually lead to positive emission anomalies, while decreases in net CH4 emissions may be associated with strong La Niña events. Precipitation was found to be more closely related to CH4 dynamics than to soil temperature and active layer depth during the study period. This study suggests that the effects of soil freezing and thawing processes and the effects of microtopography on hydrology should be considered in the quantification of CH4 emissions.
Widespread and synchronous change in deep‐ocean circulation in the North and South Atlantic during the Late Cretaceous
Authors: Robinson Stuart A. , Vance Derek
Published: March 2012

Modern thermohaline circulation plays a role in latitudinal heat transport and in deep‐ocean ventilation, yet ocean circulation may have functioned differently during past periods of extreme warmth, such as the Cretaceous. The Late Cretaceous (100–65 Ma) was an important period in the evolution of the North Atlantic Ocean, characterized by opening ocean gateways, long‐term climatic cooling and the cessation of intermittent periods of anoxia (oceanic anoxic events, OAEs). However, how these phenomena relate to deep‐water circulation is unclear. We use a proxy for deep‐water mass composition (neodymium isotopes; εNd) to show that, at North Atlantic ODP Site 1276, deep waters shifted in the early Campanian (∼78–83 Ma) from εNd values of ∼−7 to values of ∼−9, consistent with a change in the style of deep‐ocean circulation but >10 Myr after a change in bottom water oxygenation conditions. A similar, but more poorly dated, trend exists in εNd data from DSDP Site 386. The Campanian εNd transition observed in the North Atlantic records is also seen in the South Atlantic and proto‐Indian Ocean, implying a widespread and synchronous change in deep‐ocean circulation. Although a unique explanation does not exist for the change at present, we favor an interpretation that invokes Late Cretaceous climatic cooling as a driver for the formation of Southern Component Water, which flowed northward from the Southern Ocean and into the North Atlantic and proto‐Indian Oceans.
Excited spherical waves in unbounded cold magnetoplasma and applications in radio sounding
Authors: Huang Xueqin , Reinisch Bodo W.
Published: March 2012

The electromagnetic field excited by an arbitrary current source embedded in an unbounded uniform cold magnetoplasma is investigated in this paper. The Green's function method for solving the radiation equation is used, and the derived solution is valid for any cold plasma parameters. There are always two wave modes excited, and in the far field each mode has the form of a spherical wave. A refractive index for spherical waves is introduced to describe the propagation. The properties of these excited spherical waves are discussed in this paper in comparison with the plane wave representation. It is shown that the energy flow of the spherical wave is always in the radial direction, i.e., parallel to the wave normal.
Miocene exhumation of the Pamir revealed by detrital geothermochronology of Tajik rivers
Authors: Lukens C. E. , Carrapa B. , Singer B. S. , Gehrels G.
Published: March 2012

The Pamir mountains are the western continuation of the Tibetan‐Himalayan system, the largest and highest orogenic system on Earth. Detrital geothermochronology applied to modern river sands from the western Pamir of Tajikistan records the history of sediment source crystallization, cooling, and exhumation. This provides important information on the timing of tectonic processes, relief formation, and erosion during orogenesis. U‐Pb geochronology of detrital zircons and40Ar/39Ar thermochronology of white micas from five rivers draining distinct tectonic terranes in the western Pamir document Paleozoic through Cenozoic crystallization ages and a Miocene (13–21 Ma) cooling signal. Detrital zircon U‐Pb ages show Proterozoic through Cenozoic ages and affinity with Asian rocks in Tibet. The detrital40Ar/39Ar data set documents deep and regional exhumation of the Pamir mountains >30 Myr after Indo‐Asia collision, which is best explained with widespread erosion of metamorphic domes. This exhumation signal coincides with deposition of over 6 km of conglomerates in the adjacent foreland, documenting high subsidence, sedimentation, and regional exhumation in the region. Our data are consistent with a high relief landscape and orogen‐wide exhumation at ∼13–21 Ma and correlate with the timing of exhumation of the Pamir gneiss domes. This exhumation is younger in the Pamir than that observed in neighboring Tibet and is consistent with higher magnitude Cenozoic deformation and shortening in this part of the orogenic system.
Fore‐arc deformation at the transition between collision and subduction: Insights from 3‐D thermomechanical laboratory experiments
Authors: Boutelier D. , Oncken O. , Cruden A.
Published: March 2012

Three‐dimensional thermomechanical laboratory experiments of arc‐continent collision investigate the deformation of the fore arc at the transition between collision and subduction. The deformation of the plates in the collision area propagates into the subduction‐collision transition zone via along‐strike coupling of the neighboring segments of the plate boundary. In our experiments, the largest along‐strike gradient of trench‐perpendicular compression does not produce sufficiently localized shear strain in the transition zone to form a strike‐slip system because of the fast propagation of arc lithosphere failure. Deformation is continuous along‐strike, but the deformation mechanism is three‐dimensional. Progressive along‐strike structural variations arise because coupling between neighboring segments induces either advanced or delayed failure of the arc lithosphere and passive margin. The modeling results suggest that orogenic belts should experience deeper subduction of continental crust and hence higher‐pressure metamorphism where the two plates first collided than elsewhere along the plate boundary where collision subsequently propagated. Furthermore, during the initial stage of collision the accretionary wedge is partially subducted, which leads to lubrication of the interplate zone and a reduction of shear traction. Therefore, a large convergence obliquity angle does not produce a migrating fore‐arc sliver. Rather, the pressure force generated by subduction of the buoyant continental crust causes fore‐arc motion. It follows that convergence obliquity during collision does not yield trench‐parallel deformation of the fore arc and its influence on the collision process is limited. However, convergence obliquity may control the geometry of the active margin during the oceanic subduction stage prior to collision, and inherited structures may influence the propagation mechanism.
Wind‐induced resuspension in a shallow lake from Medium Resolution Imaging Spectrometer (MERIS) full‐resolution reflectances
Authors: Eleveld Marieke A.
Published: March 2012

A lack of empirical evidence impedes assessment of the spatial and temporal extent of critical conditions for recurring high turbidity in large wind‐exposed shallow lakes. Here spatiotemporal variation in total suspended matter (TSM) concentration was captured by processing 30 Envisat Medium Resolution Imaging Spectrometer (MERIS) images of a shallow lake (Markermeer) with a spectral matching algorithm. The TSM maps showed elevated downwind concentrations for moderate winds (from 4 to 9 m s−1), which occur 68% of the time. Regressions confirmed the relationship between hourly averaged wind speed and TSM. To explore critical conditions for resuspension, wind speed, linear fetch, and water depth were combined in a spatial model based on simplified linear wave equations. Remotely sensed TSM patterns matched predicted areas of resuspension from these wave equations. On average, over 70% of cells were true positive or negative, with elevated TSM matching the predicted resuspending bottom area and background TSM matching no resuspension. Images acquired during moderate winds register local resuspension. This implies that under these conditions, a critical shear stress threshold for resuspension is passed, followed by upward mixing over the few meters of water column. Images acquired during low wind speeds (≤3 m s−1) either do not show a TSM pattern or display settling because it takes several hours of low wind before all particles are removed from the visible top layer. Because of the good spatial matching, the resuspension model can also be used for future verification of the retrieval capacity of the spectral matching algorithm.
Experimental investigation of the thermal time‐series method for surface water‐groundwater interactions
Authors: Rau Gabriel C. , Andersen Martin S. , Acworth R. Ian
Published: March 2012

Diel temperature fluctuations have been used to quantify vertical water flow through saturated sediments with 1‐D analytical heat models. The underlying transport equation relies on assumptions that could be violated using field temperature records. To test the capability of this method a hydraulic laboratory experiment was designed. A mass of fully water‐saturated homogeneous sand was exposed to 19 different uniform pressure gradients inducing steady state Darcy velocities 0 < q < 25 m d−1. An areal heating grid generated steady sinusoidal thermal forcing. Multipoint sediment temperature responses demonstrated increasing spatial variability for increasing velocities. This introduced horizontal temperature gradients. Velocities calculated from heat tracing were compared to velocities independently obtained from solute slugs. Heat‐ and solute‐derived velocities agreed for q < 3 m d−1, but heat‐derived velocities were consistently larger at higher velocities. Temperature amplitude‐ and phase‐derived velocities revealed significant scatter when compared to solute velocities. This scatter reduced when amplitude‐ and phase‐derived velocities were compared for each sensor pair. The variability in heat‐derived velocities therefore represents a spatially variable flow field in the sand. However, amplitude‐ and phase‐derived velocities deviated from a 1:1 relationship at higher velocities. This can partly be explained by longitudinal thermal dispersivity, and partly by enhanced thermal spreading due to horizontal temperature gradients originating from nonuniform flow. This is surprising given the homogeneous sand and transition zone transport conditions (Pet < 0.7). These findings have implications for the quantification of velocities from field records because field conditions are likely more heterogeneous, which would exacerbate the effects found in this study.
Fiscal year 2013 energy department budget: Proposed investments in clean energy research
Authors: Balcerak Ernie
Published: March 2012

Energy and environmental research programs generally fared well in President Barack Obama's proposed budget for the Department of Energy (DOE) for fiscal year (FY) 2013. In his State of the Union address, Obama called for the United States to pursue an “all of the above” energy strategy that includes fossil fuels, as well as a variety of renewable sources of energy. The DOE budget request supports that strategy, Energy Secretary Steven Chu said in a 13 February press briefing announcing the budget proposal. The proposed budget gives DOE $27.2 billion overall, a 3.2% increase from the FY 2012 enacted budget (see Table 1). This budget “reflects some tough choices,” Chu said. The proposed budget would cut $4 billion in subsidies for oil and gas companies; many Republican members of Congress have already indicated that they oppose such cuts, suggesting that congressional approval of this budget may run into stumbling blocks. The budget would also cut funding for research and development projects that are already attracting private‐sector investment or that are not working, and would reduce some of the department's operational costs.
Observing noctilucent clouds from space and ground
Authors: Balcerak Ernie
Published: March 2012

Noctilucent clouds, which form from ice particles at high altitudes (about 83 kilometers) and enhance sky brightness after sunset, can be used to trace processes in the atmosphere—the wavy forms of the clouds can give clues about the dynamical processes in the area. Baumgarten et al. report the first observations of such clouds obtained simultaneously from the ground and from space. They measured the brightness and particle size distributions of noctilucent clouds above a research station in northern Norway on 5 August 2008 using ground‐based lidar (light detection and ranging) to observe the evolution of the clouds over time and satellite‐based instruments to observe the horizontal structure of the clouds. They demonstrate that coincident observations from lidar and satellite, combined with wind information, provide a useful way to study the evolution of noctilucent clouds on scales of minutes to hours and from 5 to 100 kilometers. (Geophysical Research Letters, doi:10.1029/2011GL049935, 2012)
Massive salp swarm tilts ocean's chemical balance
Authors: Schultz Colin
Published: March 2012

A surge of nutrients to the warm waters off the southeastern coast of Australia during the highly productive austral spring can spark an explosion in the phytoplankton population. Where phytoplankton bloom, so do the predators that feed on them. Some, like the globally prevalent salp Thalia democratica, excel at capitalizing on the transient nature of phytoplankton blooms. Salps are tiny gelatinous creatures that feed on plankton and other microorganisms by straining them from the ocean water with a fine mesh sieve. A rarity among multicellular animals, salps retain the ability to reproduce by asexual budding, with one salp spawning a clone of itself. This budding, combined with sexual reproduction, enables salp populations to grow by up to 250% per day.
Temporal and spatial evolution of dynamic support from river profiles: A framework for Madagascar
Authors: Roberts Gareth G. , Paul Jonathan D. , White Nicky , Winterbourne Jeffrey
Published: March 2012

We present a strategy for calculating uplift rates as a function of space and time from large sets of longitudinal river profiles. This strategy assumes that the shape of a river profile is controlled by the history of uplift rate and moderated by the erosional process. We assume that upstream drainage area is invariant. The algorithm was tested on a set of ∼100 river profiles which were extracted from a digital elevation model of Madagascar. This set of profiles was simultaneously inverted to obtain uplift rate as a smooth function of space and time. The fit between observed and calculated profiles is excellent and suggests that Madagascar was uplifted by 1–2 km at rates of 0.2–0.4 mm/yr during the last ∼15 Myrs. The location of Madagascar suggests that its topographic elevation is maintained by convective circulation of the sub‐lithospheric mantle. Residual depth anomalies of oceanic fragments encompassing the island show that the island straddles a dynamic topographic gradient which generates asymmetric Neogene uplift. Volcanism, warped peneplains and uplifted marine terraces corroborate the existence of youthful uplift. We suggest that sets of longitudinal river profiles contain useful information about the history of regional uplift which can be extracted by inverse modeling and calibrated by independent geologic observations.