bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship of obesity, Androgen receptor genotypes and biochemical failure after radical prostatectomy
Authors: Zeigler‐Johnson Charnita , Weber Anita , Spangler Elaine , Panossian Saarene , Rebbeck Timothy R. , Malkowicz S. Bruce
Published: October 2011

BACKGROUND

Obesity and androgen metabolism have been implicated in the progression of prostate cancer. Obesity has been associated with increased risk for advanced disease and biochemical failure after treatment. This association may be the result of changes in androgen metabolism that occur with obesity and are mediated by the androgen receptor (AR).

METHODS

To evaluate the effects of obesity and AR polymorphisms on biochemical failure, we conducted a study of 536 Caucasian prostate cancer cases. We determined the relationship between time to biochemical failure and obesity stratified by short and long AR‐CAG and AR‐GGN repeat sequence. The AR repeat groups were dichotomized at the median number of repeats for each polymorphism.

RESULTS

An association was found for obesity in the short CAG group (HR = 3.45, 95% CI = 1.00–11.96). Among obese patients diagnosed with localized disease (T1/T2), the risk of biochemical failure was significantly higher (HR = 7.05, 95% CI = 1.55–32.06). No difference was observed for high stage (T3/T4) obese patients. Additionally, no differences in biochemical failure were observed in obese and non‐obese men grouped by number of AR‐GGN repeats.

CONCLUSIONS

Obesity is significantly associated with increased risk of biochemical failure in men with the high‐risk short CAG sequence on the AR gene. This effect is not observed in men with long CAG repeats. Therefore, it appears that the relationship between biochemical failure and obesity may be modified by the AR‐CAG repeat pattern. The short AR‐CAG genotype may be more responsive to an altered hormonal milieu created by obesity. Prostate 72:984–990, 2012. © 2011 Wiley Periodicals, Inc.
Opposing roles of ERα and ERβ in the genesis and progression of adenocarcinoma in the rat ventral prostate
Authors: Attia D.M.A. , Ederveen A.G.H.
Published: October 2011

BACKGROUND

Prostate cancer is a common malignancy in men and although hormone ablation therapy is effective, men develop hormone resistance. There is need for therapies applicable earlier, such as treatment of prostatic intraepithelial neoplasia (PIN). Estrogens besides androgens play a role in prostate cancer pathogenesis via two receptors ERα and ERβ and both receptors are thought to play different, opposing, roles with ERα having proliferative properties and ERβ having anti‐proliferative properties. To differentiate between the roles both receptors play in prostate cancer an ERα and an ERβ agonist, ERA‐45 and ERB‐26, have been tested in a rodent model for prostate carcinogenesis.

METHODS

The influence of ERα on prostate cancer progression was studied in intact male rats treated with testosterone in combination with the ERα agonist, ERA‐45 for either a long‐term (20‐week) period or a shorter term (6‐week) period. The ERβ agonist was tested in the shorter term model in intact male rats treated with testosterone in combination with the ERα agonist, ERA‐45, followed by administration of the ERβ agonist, ERB‐26, during the last 2 weeks.

RESULTS

Treatment of rats with testosterone in combination with ERA‐45 induced mild PIN lesions at 6 weeks and severe precancerous PIN lesions at 20 weeks. The ERβ agonist prevented the onset of PIN lesions at 6 weeks. Moreover, prostate epithelial cell apoptosis was increased and proliferation was decreased.

CONCLUSION

These findings confirm the opposing roles ERα and ERβ play in prostate carcinogenesis and suggest a therapeutic opportunity of ERβ for treating precancerous PIN lesions. Prostate 72:1013–1022, 2012. © 2011 Wiley Periodicals, Inc.
Development of a needle insertion manipulator for central venous catheterization
Authors: Kobayashi Yo , Hong Jaesung , Hamano Ryutaro , Okada Kaoru , Fujie Masakatsu G. , Hashizume Makoto
Published: October 2011

Background

Central venous catheterization is a procedure in which a doctor inserts a catheter into a patient's vein for transfusions. Risks of this procedure include bleeding from the puncture of blood vessels and pneumothorax caused by pleural puncture. To avoid these and other risks, physicians are required to ensure that the needle is inserted securely and that it stops within the vein.

Methods

We propose a robotic system for assisting venous puncture that is capable of alleviating the difficulties encountered during the conventional procedure, as well as minimizing the risks of complications. This paper describes the design and results of experiments conducted using a needle insertion manipulator. First, we investigated the relation between insertion force and angle into the vein to determine the appropriate insertion angle in relation to the blood vessel under physical conditions. The results indicated that the reaction force can be used to gauge whether the needle has been inserted into the vein in cases where the insertion angle is in the range 10–20°. Based on this result, we determined the mechanisms of the puncture device, which comprises a small, compact configuration. Experiments for accuracy validation were performed on a phantom.

Results

We evaluated the positioning accuracy using ultrasound images, and the results indicated an accuracy of 1.0 mm or better, which is considered feasible for venous puncture. In the phantom experiments, we confirmed that our manipulator was capable of placing the needle within the vein.

Conclusions

The feasibility of this system was demonstrated in our experiments. Further studies, such as in vivo experiments, are required. Copyright © 2011 John Wiley & Sons, Ltd.
On absolute (robust) stability: slope restrictions andstability multipliers
Authors: Răsvan Vl. , Danciu Daniela , Popescu D.
Published: October 2011

Absolute stability for systems with several sector‐restricted and slope‐restricted nonlinearities is studied in this paper. A critical analysis of the multipliers is performed and the multipliers of Yakubovich type are chosen because the stability inequality is obtained with a minimum of technical assumptions. The main part of the paper is devoted to obtaining the Yakubovich‐type criterion in the unified context of stable, critical, and unstable cases for the linear part. The paper is motivated by the problem of pilot in‐the‐loop oscillations of the aircrafts where critical and unstable cases appear and the saturation nonlinearity is both sector and slope restricted. The paper contains some applications of the frequency domain inequalities. The conclusions show a ‘parsimony principle’: using as few free parameters as possible to obtain the largest possible domain of stability. The paper ends with conclusions and hints for further development. Copyright © 2011 John Wiley & Sons, Ltd.
Influence of nonstationary atomic mixing on depth resolution in sputter depth profiling
Authors: Wang J. Y. , Liu Y. , Hofmann S. , Kovac J.
Published: October 2011

Atomic mixing is an important parameter in the quantitative description of sputter depth profiles by the mixing‐roughness‐information depth model. By changing the atomic mixing length from zero to a stationary state value, it is possible to simulate the transient zone at the beginning of sputter depth profiling with noble gas ions, which is important for shallow depth profiles. Accordingly, the depth profile is gradually broadened and the depth resolution value increases with sputtered depth. Applications of changing the atomic mixing length in the mixing‐roughness‐information depth model are shown to yield excellent fits for measured AES depth profiles of N+ implantation in Co films. Copyright © 2011 John Wiley & Sons, Ltd.
An empirical study of learning by osmosis in global software engineering
Authors: Lago Patricia , Muccini Henry , Babar Muhammad Ali
Published: October 2011

To teach global software engineering, we devised a complementary distributed module with a shared project involving both local and international teams. In local teams, students are located at the same university and trained in one of the two complementary topics. In international teams, students are located at two different universities and trained in one of the two complementary topics. This study empirically investigates whether the students in the international teams can compensate the extra effort required to deal with communication, coordination, and collaboration issues that characterize global software engineering projects with learning by osmosis (i.e., by transferring knowledge among globally distributed teams trained on different topics). The results show that there was no statistically significant difference between the performance of local and international teams. We assert that the students in the international and local teams perform equally well, thanks to learning by osmosis. However, our analysis of the self‐reported questionnaire data revealed that most of the participants (i.e., 70%) would like to work in local teams in real‐life project, 74% of the participants thought international teams were less efficient, and 41% of the participants reported lack of trust in their international team members compared with their local team members. Copyright © 2011 John Wiley & Sons, Ltd.
Disequilibrium, Development and Resilience Through Adult Life
Authors: Henning Pamela Buckle
Published: October 2011

In the field of mental health, resilience is understood as a psychological characteristic intimately entwined with the experience of disequilibrium. Originally, the resilience literature focused on children. But psychological development can continue beyond childhood. Recently, psychologists have begun to examine the resilience that arises—or does not—through the vicissitudes of adult life as well. Psychologically, a human being can be considered a complex system of drives, conflicts, capacities, hopes and so on. The human life span can be conceptualized as repeated experiences of stability and disequilibrium for a person's psychological system. From that stability and disequilibrium come the emergence of new abilities and worldviews. One possible outcome of the experience of repeated psychological disequilibrium inherent to adult life is the development of psychological resilience. This paper examines the affective experience of psychological development through adult life and what it means to be actively receptive to development in a way that optimizes the growth of resilience throughout adulthood. This article aims to make several contributions to the systems sciences. First, it brings psychology back into conversation with the systems community after an absence, in the International Society for the Systems Sciences at least, of many years. Second, systems theorists have paid little attention to the affective experience of disequilibrium—a recognized systems process—in a human system like an adult person. Third, to the mental health community, this paper seeks to communicate that perhaps much of the suffering and negative affect people experience through adulthood can be reframed from psychopathology to developmental transition—to disequilibrium—and the vulnerability and challenges that go with it. Copyright © 2011 John Wiley & Sons, Ltd.
Plastic hinge length of reinforced concrete columns subjected to both far‐fault and near‐fault ground motions having forward directivity
Authors: Mortezaei Alireza , Ronagh Hamid Reza
Published: October 2011

In a strong earthquake, a standard reinforced concrete (RC) column may develop plastic deformations in regions often termed as plastic hinge regions. A plastic hinge is basically an energy dampening device that dampens energy through the plastic rotation of a rigid column connection, which triggers redistribution of bending moments. The formation of a plastic hinge in an RC column in regions that experience inelastic actions depends on the characteristics of the earthquakes as well as the column details. Recordings from recent earthquakes have provided evidence that ground motions in the near field of a rupturing fault can contain a large energy or ‘directivity’ pulse. A directivity pulse occurs when the propagation of the fault proceeds at nearly the same rate as the shear wave velocity. This pulse is seen in the forward direction of the rupture and can cause considerable damage during an earthquake, especially to structures with natural periods that are close to those of the pulse. In the present paper, 1316 inelastic time‐history analyses have been performed to predict the nonlinear behaviour of RC columns under both far‐fault and near‐fault ground motions. The effects of axial load, height over depth ratio and amount of longitudinal reinforcement, as well as different characteristics of earthquakes, were evaluated analytically by finite element methods and the results were compared with corresponding experimental data. Based on the results, simple expressions were proposed that can be used to estimate plastic hinge length of RC columns subjected to both far‐fault and near‐fault earthquakes that contain a forward‐directivity effect. Copyright © 2011 John Wiley & Sons, Ltd.
Dual‐mixed hp finite element model for elastic cylindrical shells
Authors: Tóth B.
Published: October 2011

A dimensionally reduced cylindrical shell model using a three‐field complementary energy‐based Hellinger–Reissner's variational principle of non‐symmetric stresses, rotations, and displacements is presented. An important property of the shell model is that the classical kinematical hypotheses regarding the deformation of the normal to the shell mid‐surface are not applied. A dual‐mixed hp finite element model with stable polynomial stress‐ and displacement interpolation and C0 continuous normal components of stresses is constructed and presented for the bending‐shearing problem, using unmodified three‐dimensional inverse stress‐strain relations for linearly elastic materials. It is shown through an example that the convergences in the energy norm as well as in the maximum norm of stresses and displacements are rapid for both h‐extension and p‐approximation, not only for thin but also for moderately thick shells loaded axisymmetrically, even if the Poisson ratio is close to the incompressibility limit of 0.5.
Antecedents to ambidexterity competency in high technology organizations⋆
Authors: Chandrasekaran Aravind , Linderman Kevin , Schroeder Roger
Published: October 2011

High tech organizations confront dual demands of exploring new products/processes and exploiting existing products/processes. Research shows that ambidextrous organizations can better manage these dual demands, but our understanding of the antecedents that lead to ambidexterity is still emerging. In addition, previous research has taken a piecemeal approach to understand ambidexterity and does not fully consider its multilevel nature. This research takes a multilevel perspective and argues that a competency in ambidexterity involves three capabilities at different organizational levels: decision risk (strategic level), structural differentiation (project level), and contextual alignment (meso level). After correcting for endogeneity we empirically examine the relationship between these antecedents and ambidexterity competency by collecting multi‐level data from 34 high tech business units and 110 exploration and exploitation R&D projects. The results indicate that decision risk and contextual alignment affect ambidexterity competency for high tech organizations. Structural differentiation does not affect ambidexterity competency but has mixed effects on R&D project performance.
Prandtl and Rayleigh number dependence of heat transport in high Rayleigh number thermal convection
Authors: Stevens Richard J. A. M. , Lohse Detlef , Verzicco Roberto
Published: October 2011

Results from direct numerical simulation for three-dimensional Rayleigh–Bénard convection in samples of aspect ratio $\Gamma = 0. 23$ and $\Gamma = 1/ 2$ up to Rayleigh number $\mathit{Ra}= 2\ensuremath{\times} 1{0}^{12} $ are presented. The broad range of Prandtl numbers $0. 5\lt \mathit{Pr}\lt 10$ is considered. In contrast to some experiments, we do not see any increase in $\mathit{Nu}/ {\mathit{Ra}}^{1/ 3} $ with increasing $\mathit{Ra}$, neither due to an increasing $\mathit{Pr}$, nor due to constant heat flux boundary conditions at the bottom plate instead of constant temperature boundary conditions. Even at these very high $\mathit{Ra}$, both the thermal and kinetic boundary layer thicknesses obey Prandtl–Blasius scaling.
Expertise and Scale of Conflict: Governments as Advocates in American Indian Politics
Authors: EVANS LAURA E.
Published: October 2011

How do American Indian tribal governments relate to nearby local governments? Do insights gleaned from these cases illuminate the constraints and opportunities that marginalized groups face within any system of federalism? What circumstances of marginalized governments help or hinder their effectiveness? Although some Native American tribes have transformed their fortunes with highly profitable casinos, most continue to face stark disadvantages. Some tribal governments, despite limited opportunities prevail locally by cultivating policy and political expertise. This analysis demonstrates that such expertise can be developed, even when resources are scarce.
Natural occurrence of lethal aspergillosis in the cattle tickRhipicephalus (Boophilus) microplus(Acari:Ixodidae)
Authors: MIRANDA-MIRANDA E. , COSSIO-BAYUGAR R. , MARTÍNEZ-IBAÑEZ F. , CASASANERO-ORDUÑA R. , FOLCH-MALLOL J.
Published: October 2011

The purpose of this study was to describe an unreported entomopathogenic fungus that naturally infects the cattle tickRhipicephalus (Boophilus) microplus(Acari: Ixodidae). Engorged female ticks, showed symptoms of fungal infection after controlled tick infestation of cattle. Infected ticks developed a distinctive dark colour, a pale mould grew over the cuticle and the ticks eventually died covered with fungal conidiophores. The responsible fungus was isolated and cultured on mycological medium and submitted to microscopic morphology, biochemical phenotyping and 18S rRNA ribotyping analyses, which identified it as aflatoxin-producingAspergillus flavus. Spores from the cultured fungus were experimentally sprayed over healthy engorged female ticks, obtaining an 80% prevalence of experimental infection of healthy ticks and their egg masses, the larval progeny after incubation under laboratory conditions was also infected. These results demonstrate thatA. flavusis the causative agent of the natural fungal disease of the cattle tickR. microplusdescribed here.
Communities of place and communities of interest? An exploration of their changing role in later life
Authors: MEANS ROBIN , EVANS SIMON
Published: October 2011

Social gerontologists have long grappled with the meaning of ‘community’ to older people. This paper lies within this tradition and focuses on the extent to which the past emphasis upon communities of place needs to be rebalanced or rethought in the light of emerging evidence for the growing engagement of older people in communities of interest linked to friendships, enthusiasms and their increasing spending power. This theoretical paper highlights the traditional emphasis on the role of community and place in later life and explores the emergence of a debate about communities of interest linked to such factors as the ‘discovery’ of ‘the Third Age’, marketisation, consumerism, the importance of social interaction in the lives of many older people, and the impact of the internet and virtual communities. This debate is placed in an international policy context in which numerous governments are concerned about the greying of the global population and the consequent desire to promote ‘ageing well’ to offset resultant health and social care costs. The paper argues for a reconceptualisation of community through a more sophisticated view of ‘place’ and ‘interest’ that avoids false dichotomies between the two and acknowledges the impact of social, economic and cultural change upon the lives of older people.
The Harmonious Unfortunate: new light on Catherine Tofts
Authors: Baldwin Olive , Wilson Thelma
Published: October 2011

Catherine Tofts, ‘the first English prima donna’, was the female lead in the all-sung operas in the Italian style performed on the London stage from1705, but little has previously been known about her early life or musical training. This article draws on various sources, including her father's will, a petition she wrote in 1704 and Delarivier Manley's Memoirs of Europe to show that her family background was Scottish and that she grew up in the household of Bishop Gilbert Burnet. It names possible singing teachers and lovers, and shows that she did not leave the stage in 1709 because of mental instability, as has been assumed, but because of debt and the consequent need to escape from her creditors. The end of her career shows the difficulties faced by a leading English singer when Italians, particularly the castrati, came to dominate the operatic scene in London.
Global shocks, economic growth and financial crises: 120 years of New Zealand experience
Authors: Bordo Michael , Hargreaves David , Kida Mizuho
Published: October 2011

We identify the timing of currency, banking crises and sudden stops in New Zealand from 1880 to 2008 using methodologies from the international literature and consider the extent to which the empirical models in that literature can explain New Zealand's crisis history. We find that the cross-country evidence on the determinants of crises fits New Zealand experience reasonably well. A number of the risk factors that correlate with crises internationally – such as domestic imbalances, external debt, and currency mismatches – were elevated for New Zealand when the country had more frequent crises and have improved in the recent (more stable) period. However, a time-series analysis of New Zealand growth over 120 years shows that global factors – such as the US growth rate and terms of trade – explain New Zealand growth fairly well, and that crisis-dummy variables do not have substantial additional explanatory power. This suggests that having sound institutions and policies may help avoid severe domestic crises, but will not be sufficient to avoid the domestic economic impact of the global business cycle.
BEYOND UNITY
Authors: Beltrán Cristina
Published: October 2011

Lawrie Balfour and Robert Gooding-Williams have given us powerful new works of scholarship on the political thought of W. E. B. Du Bois. Not only do these publications enrich the field of Du Bois scholarship, they exemplify the exciting possibilities at the intersection of political theory and race politics.
TOWARD A PROGRESSIVE DEMOCRATIC POLITICS OF RACE
Authors: Smith Rogers M.
Published: October 2011

The two books that have occasioned this symposium represent efforts to research thoroughly, think rigorously, and argue honestly about complex and significant issues of race and ethnicity in America. There is much to be learned from them on many topics. I read them chiefly for insights about whether and how a defensibly democratic politics of egalitarian change can be achieved by, for, and with racial minorities in a country whose majorities, like most majorities, have long been reluctant to pursue policies that did not predominantly benefit themselves. I raise some challenges to the perspectives offered in these books, but only as an effort, kindred in aim if not achievement, to carry forward the work they have thus far so nobly advanced.
ANTIFOUNDATIONALISM, LEADERSHIP, BLACK POLITICS
Authors: Gooding-Williams Robert
Published: October 2011

In the remarks that follow, I attempt to clarify and further to develop some of the key concepts and arguments that I set forth inIn the Shadow of Du Bois(2009). Specifically, I respond to issues that Rogers Smith and Tommie Shelby address with regard to the relationship between elite and democratic politics; to questions that Smith and Cristina Beltrán pose with regard to my “no-foundations” analysis of Black politics; and to a worry Smith presents with regard to my effort to reorient the critique of Black poverty from social theories framed by a technical interest in normalizing the behavior of the ghetto poor to an emancipatory interest in fostering the radical reform of an oppressive social order. I begin with Smith's criticisms and then turn to Shelby's and Beltrán's essays.
THE MOYNIHAN REPORT AND ITS AFTERMATHS
Authors: Gans Herbert J.
Published: October 2011

The Moynihan Report of 1965 will soon be fifty years old, and some social scientists now venerate it as a sterling application of social science data and analysis by the federal government. This author, who was directly involved in events connected with the release of the Report, does not agree; this article examines the shortcomings of the Report. I argue that Moynihan's analysis, which intended to investigate the ties between Black male unemployment and the Black family, actually devoted most of its attention to the high proportion of single-parent families in the poor Black population, treating it as one symptom of a “tangle of pathology” that stood in the way of this population's escape from joblessness and poverty. Today, the Report is being hailed as having predicted the current and still worsening state of the poor Black family. Moynihan's work is also being reinterpreted as an early application of cultural analysis, thereby further drawing attention away from the job-related issues which led Moynihan to undertake his study. Moynihan himself made significant contributions to antipoverty policy later in his career, but his Report does not deserve the worship it continues to receive.
POLITICAL HAIR
Authors: Johnson Kimberley S.
Published: October 2011

This article argues that African American hair is a political matter by examining the little-known role of state occupational licensing of African American hair care. By focusing on recent legal challenges and legislative battles over state regulation of hair-care provision for African Americans, the article traces state authorities' responses to struggles over market share between licensed, and often native-born, African American beauticians, and typically unlicensed, and often recent African immigrant, hair braiders. Hair braiders challenged state regulatory oversight by invoking racial deference claims, in which they argued that braiding was a “cultural practice” that should be exempt from state regulation. A statistical analysis of state regulatory decision making revealed that states varied widely in addressing the issue of African American hair care. While racial deference claims, in the form of legal cases, put pressure on states to exempt hair braiders from regulatory oversight, by and large, most states did not choose this path. For states that did choose to address the demands for market protection or market relief, the choices were mostly in the direction of enacting new regulations or actively incorporating hair braiders under existing regulations. Despite the invocation of racial deference claims, African American hair care was not freed from state oversight—state regulators became more flexible in their oversight of Black hair care rooted in their concerns over public safety as well as the demands from a variety of interest groups. The analysis reveals that when race/gender and state regulation intersect, traditional economic theories of occupational licensing are not sufficient; an intersectional approach can better explain policy outcomes.
“I Got That Something That Makes Me Want to Shout”: James Brown, Religion, and Gospel Music in Augusta, Georgia
Authors: ALLEN CARRIE
Published: October 2011

Using ethnographic and archival data, this article explores aspects of global superstar James Brown's participation in the black gospel music community of Augusta, Georgia, from the 1980s until his death in 2006. Using rare footage of Brown performing sacred music on a local gospel music television program, the article builds on scholars’ longtime recognition of Brown's engagement with black sacred song by engaging the singer's negotiation of sacred and secular musical and cultural boundaries from the perspective of his gospel performances. The article also examines Brown's personal relationships with local gospel musicians, ultimately arguing that his involvement with Augusta's gospel tradition near the end of his life provided Brown with an alternative social space for articulating a musical and personal identity somewhat separate from his mainstream media image.
Congress examines administration's coal research priorities
Authors: Showstack Randy
Published: October 2011

While the Obama administration has proposed a shift in coal research funding to further emphasize carbon capture and sequestration (CCS) programs in its fiscal year (FY) 2012 budget request, Republicans and several witnesses at a 13 October hearing of a subcommittee of the House of Representatives' Committee on Science, Space, and Technology questioned those priorities, called for additional federal funding for coal research, and defended the use of coal as a major part of the U.S. energy sector. The administration's FY 2012 budget requests $291.4 million to fund the Department of Energy's (DOE) CCS and power systems program while zeroing out funding for DOE's fuels and power systems program (which includes funding for coal research) and shifting some of its line items to the CCS program. The FY 2011 continuing resolution has funded the fuels and power systems program at $400.2 million, including $142 million for carbon sequestration, $64.8 million for innovations for existing plants, and funding for other subprograms such as advanced integrated gasification combined cycle ($52.9 million), fuel cells ($49.8 million), and advanced research ($47.6 million).
Constructing a database of terrestrial radiocarbon measurements
Authors: Trumbore Susan , Torn Margaret , Smith Lydia
Published: October 2011

Terrestrial Radiocarbon Database Workshop; Berkeley, California, 20–22 July 2011 Soils play a large role in the global carbon (C) cycle, but soil C stocks and dynamics remain highly uncertain. Radiocarbon (14C) observations provide critical information on the rates of exchange of soil C with the atmosphere and hydrosphere and how those rates vary with edaphic (soil‐related) factors and over a range of time scales. For example, the degree to which radio decay has affected 14C demonstrates the importance of short‐range‐order minerals for stabilizing organic C on millennial time scales in some soils. Time series that track the infiltration of “bomb” 14C help identify the components of soil C that cycle on decadal to centennial time scales.
Inaugural Climate Communications Prize winner announced
Authors: McEntee Chris , Fine Rana
Published: October 2011

In recognition of Gavin Schmidt's exceptional work as a climate communicator, AGU has selected him as the recipient of its inaugural Climate Communications Prize. Schmidt is a climate scientist at the NASA Goddard Institute for Space Studies and cofounder of the RealClimate.org blog. RealClimate.org covers areas of science related to climate—from present‐day measurements to paleoclimate proxies, from natural climate variation to anthropogenic change. Schmidt has also worked with photographers on a popular science book, on museum exhibits, and on online courses and has often appeared on TV and radio and in print.
Observing changes in atmospheric heat content
Authors: Balcerak Ernie
Published: October 2011

Globally, air temperatures near the surface over land have been rising in recent decades, and this has been presented as solid evidence of global warming. However, some scientists have argued that total heat content (energy), rather than temperature, should be used as a metric of warming trends. Surface air temperature is only one component of the energy content of the surface atmosphere—kinetic energy and latent heat also contribute. Peterson et al. present the first study to use observational data to estimate global changes in surface energy of the atmosphere over time. They include temperature, kinetic energy, and latent heat in their analysis. The authors found that total global surface atmospheric energy and heat content have increased since the 1970s, even though kinetic energy decreased slightly and in some regions latent heat declined while temperature increased.
Geomagnetic storms could alter near‐Earth radiation environment
Authors: Balcerak Ernie
Published: October 2011

Potentially hazardous space weather could affect satellites traversing the inner radiation zone, closer to Earth than previously thought, a new study shows. The Earth's radiation belts have a two‐layer structure, and it had been thought that most geomagnetic storms, which are triggered by solar activity, affected only the outer belt. However, simulations by Shprits et al. show that during a very large geomagnetic storm, electrons could actually be accelerated in the inner radiation belt layer. Changes in the near‐Earth radiation environment could then persist for several years after a large geomagnetic storm. High‐energy electrons can damage satellites, and the altered radiation environment near Earth could significantly reduce the lifetime of satellites in that zone. The authors suggest that a large geomagnetic storm that reached the inner radiation belt could have potentially devastating economic impacts. (Space Weather, doi:10.1029/2011SW000662, 2011)
Earthquake‐generated landslides: An important control of riverbed erosion
Authors: Schultz Colin
Published: October 2011

River erosion is a powerful shaper of topography, cutting through bedrock and over time converting smooth terrain to rolling hills or jagged cliffs. The rate of bedrock incision is influenced by the stream's slope and width, the water's flow rate, and the presence of sediment, among other factors. Researchers know sediment can play two conflicting roles: If the river's sediment load is low, it acts like sandpaper, increasing the rate of riverbed erosion. If there is plentiful sediment in the river, it forms a protective barrier along the riverbed, limiting erosion. What remains uncertain, however, is the influence of large, periodic inputs of sediment that enter rivers because of landslides or other extreme events.
“Great Calcite Belt” encircles Southern Ocean
Authors: Balcerak Ernie
Published: October 2011

Coccolithophores, a type of single‐celled phytoplankton, produce 2‐micrometer‐diameter carbonate shells known as coccoliths. The distribution of coccolithophores is influenced by nutrient availability and physical stratification of the ocean. Moreover, their ability to produce coccoliths could be affected by ocean acidification. The abundance and distribution of these plankton can provide important information about the marine carbon cycle and may be affected by future acidity of the oceans.
Why self-catalyzed nanowires are most suitable for large-scale hierarchical integrated designs of nanowire nanoelectronics
Authors: Noor Mohammad S.
Published: October 2011

Nanowires are grown by a variety of mechanisms, including vapor-liquid-solid, vapor-quasiliquid-solid or vapor-quasisolid-solid, oxide-assisted growth, and self-catalytic growth (SCG) mechanisms. A critical analysis of the suitability of self-catalyzed nanowires, as compared to other nanowires, for next-generation technology development has been carried out. Basic causes of superiority of self-catalyzed (SCG) nanowires over other nanowires have been described. Polytypism in nanowires has been studied, and a model for polytypism has been proposed. The model predicts polytypism in good agreement with available experiments. This model, together with various evidences, demonstrates lower defects, dislocations, and stacking faults in SCG nanowires, as compared to those in other nanowires. Calculations of carrier mobility due to dislocation scattering, ionized impurity scattering, and acoustic phonon scattering explain the impact of defects, dislocations, and stacking faults on carrier transports in SCG and other nanowires. Analyses of growth mechanisms for nanowire growth directions indicate SCG nanowires to exhibit the most controlled growth directions. In-depth investigation uncovers the fundamental physics underlying the control of growth direction by the SCG mechanism. Self-organization of nanowires in large hierarchical arrays is crucial for ultra large-scale integration (ULSI). Unique features and advantages of self-organized SCG nanowires, unlike other nanowires, for this ULSI have been discussed. Investigations of nanowire dimension indicate self-catalyzed nanowires to have better control of dimension, higher stability, and higher probability, even for thinner structures. Theoretical calculations show that self-catalyzed nanowires, unlike catalyst-mediated nanowires, can have higher growth rate and lower growth temperature. Nanowire and nanotube characteristics have been found also to dictate the performance of nanoelectromechanical systems. Defects, such as stacking faults, dislocations, and nanopipes, which are common in catalyst-mediated nanowires and nanotubes, adversely affect the efficiency of nanowire (nanotube) nanoelectro-mechanical devices. The influence of seed-to-seed distance and collection area radius on the self-catalyzed, self-aligned nanowire growths in large arrays of seeds has been examined. A hypothesis has been presented for this. The present results are in good agreement with experiments. These results suggest that the SCG nanowires are perhaps the best vehicles for revolutionary advancement of tomorrow’s nanotechnology.
Degenerate mixing of plasma waves on cold, magnetized single-species plasmas
Authors: Anderson M. W. , O’Neil T. M. , Dubin D. H. E. , Gould R. W.
Published: October 2011

In the cold-fluid dispersion relation ω=ωp/[1+(k⊥/kz)2]1/2 for Trivelpiece-Gould waves on an infinitely long magnetized plasma cylinder, the transverse and axial wavenumbers appear only in the combination k⊥/kz. As a result, for any frequency ω<ωp, there are infinitely many degenerate waves, all having the same value of k⊥/kz. On a cold finite-length plasma column, these degenerate waves reflect into one another at the ends; thus, each standing-wave normal mode of the bounded plasma is a mixture of many degenerate waves, not a single standing wave as is often assumed. A striking feature of the many-wave modes is that the short-wavelength waves often add constructively along resonance cones given by dz/dr=±(ωp2/ω2-1)1/2. Also, the presence of short wavelengths in the admixture for a predominantly long-wavelength mode enhances the viscous damping beyond what the single-wave approximation would predict. Here, numerical solutions are obtained for modes of a cylindrical plasma column with rounded ends. Exploiting the fact that the modes of a spheroidal plasma are known analytically (the Dubin modes), a perturbation analysis is used to investigate the mixing of low-order, nearly degenerate Dubin modes caused by small deformations of a plasma spheroid.
In-plane thermal conductivity determination through thermoreflectance analysis and measurements
Authors: Aubain Max S. , Bandaru Prabhakar R.
Published: October 2011

A scanning thermoreflectance (TR) technique through which the surface temperature profile of heated thin films may be ascertained and modeled to yield the in-plane thermal conductivity (κip) is discussed. The TR intensity is shown to be a sensitive function of the film thickness, its thermo-optic materials properties, and the substrate geometry. A reduction in the thermal conductivity of silicon thin films is then demonstrated deploying the technique. A comparison of the estimated conductivity values to those obtained using other methodologies supports the validity of our method and suggests that complete isolation of the thin film from the substrate may not be required for extracting κip.
Developmental mechanism for the resistance change effect in perovskite oxide-based resistive random access memory consisting of Bi2Sr2CaCu2O8+δ bulk single crystal
Authors: Hanada A. , Kinoshita K. , Matsubara K. , Fukuhara T. , Kishida S.
Published: October 2011

Resistive random access memory (ReRAM) structures of M/Bi2Sr2CaCu2O8+δ (Bi-2212) bulk single crystal/Pt (M = Al, Pt) were prepared and their memory characteristics and superconducting properties were evaluated. The resistance change effect developed only in the Al/Bi-2212/Pt structure and was enhanced with decreasing critical temperature by annealing in Ar atmosphere. Due to the large resistance anisotropy of bulk Bi-2212 single crystals, the resistance change effect was confirmed to occur at the interface between the Al electrode and the Bi-2212 single crystal. These results indicate that introduction of an oxygen-depleted layer to the Bi-2212 single crystal is required to develop the resistance change effect, which could be achieved by the deposition of electrodes with low Gibbs free energy and raising the temperature to exceed the activation energy for oxygen ions to move from Bi-2212 to the electrode. A model is proposed to explain the resistive switching of perovskite oxide-based ReRAM by generation/recovery of the oxygen-depleted layer. The resistance change effect developed also in the Pt/Bi-2212/Au structure annealed in hydrogen gas, in which an oxygen-depleted layer is formed with the assistance of catalytic effect of Pt on the surface of the Bi-2212 at the Pt/Bi-2212 interface, proving the validity of the model.
Softening of phonons by lattice defects and structural strain in heavy ion irradiated nanocrystalline zinc oxide films
Authors: Singh Fouran , Singh R. G. , Kumar Vinod , Khan S. A. , Pivin J. C.
Published: October 2011

Origin of the Raman mode in nanocrystalline zinc oxide in the vicinity of A1 (LO) phonon mode induced by energetic heavy ions is reported. The evolution of this mode in the irradiated films is ascribed to the effect of disorder and the high density of lattice defects induced by irradiation. The presence of such defects is confirmed by the reduction in the intensity of E2 (high) mode and band bending of the near band edge absorption. A softening of the evolved Raman mode with increasing in ion fluence is also observed. This softening cannot be attributed to spatial confinement of phonons, as the sizes of the crystallites are large. Therefore, it is explained in terms of the combined effects of phonon localization by lattice defects and the structural strain in the lattice induced by electronic energy loss transferred by energetic heavy ions.
Head-on collision of dust-ion-acoustic soliton in quantum pair-ion plasma
Authors: Chatterjee Prasanta , Ghorui Malay kr. , Wong C. S.
Published: October 2011

In this paper, we study the head-on collision between two dust ion acoustic solitons in quantum pair-ion plasma. Using the extended Poincare–Lighthill–Kuo method, we obtain the Korteweg–de Vries equation, the phase shifts, and the trajectories after the head-on collision of the two dust ion acoustic solitons. It is observed that the phase shifts are significantly affected by the values of the quantum parameter H, the ratio of the multiples of the charge state and density of positive ions to that of the negative ions β and the concentration of the negatively charged dust particles δ.
Anomalous skin effects in relativistic parallel propagating weakly magnetized electron plasma waves
Authors: Abbas Gohar , Bashir M. F. , Murtaza G.
Published: October 2011

Fully relativistic analysis of anomalous skin effects for parallel propagating waves in a weakly magnetized electron plasma is presented and general expressions for longitudinal and transverse permittivites are derived. It is found that the penetration depth for R- and L-waves increases as we move from non-relativistic to highly relativistic regime. The ambient magnetic field reduces/enhances the skin effects for R-wave/L-wave as the strength of the field is increased. In general, the weak magnetic field effects are pronounced for the weakly relativistic regime as compared with other relativistic cases. The results are also graphically illustrated. On switching off the magnetic field, previous results for field free case are retrieved [A. F. Alexandrov, A. S. Bogdankevich, and A. A. Rukhadze, Priniples of Plasma Electrodynamics (Springer-Verlag, Berlin, Heidelberg, 1984), Vol. 9, p. 106].
The internal waves and Rayleigh-Taylor instability in compressible quantum plasmas
Authors: Lu H. L. , Qiu X. M.
Published: October 2011

In this paper, we investigate the quantum effect on internal waves and Rayleigh-Taylor (RT) instability in compressible quantum plasmas. First of all, let us consider the case of the limit of short wavelength perturbations. In the case, the dispersion relation including quantum and compressibility effects and the RT instability growth rate can be derived using Wentzel-Kramers-Brillouin method. The results show that the internal waves can propagate along the transverse direction due to the quantum effect, which was first pointed out by Bychkov et al. [Phys. Lett. A 372, 3042 (2008)], and the coupling between it and compressibility effect, which is found out in this paper. Then, without making the approximation assumption of short wavelength limit, we examine the linearized perturbation equation following Qiu et al.’s solving process [Phys. Plasmas 10, 2956 (2003)]. It is found that the quantum effect always stabilizes the RT instability in either incompressible or compressible quantum plasmas. Moreover, in the latter case, the coupling between it and compressibility effect makes this stabilization further enhance.
Observation of the Plateau-Rayleigh capillary instability in multi-material optical fibers
Authors: Shabahang S. , Kaufman J. J. , Deng D. S. , Abouraddy A. F.
Published: October 2011

We report the observation of the Plateau-Rayleigh capillary instability during the tapering of a multi-material optical fiber. The fiber core is a glass, and the cladding is an amorphous polymer. The instability is manifested in the breakup of the core into a periodic string of size-tunable micro-scale droplets embedded along the fiber axis. The particle diameters may be tuned in the 1–20 μm range through control of the tapering speed and temperature. Extending this approach to the fabrication of polymer and glass nanoparticles appears feasible.
Analysis of energy transfer processes in Yb3+-Tb3+ co-doped, low-silica calcium aluminosilicate glasses
Authors: Terra I. A. A. , Borrero-González L. J. , Nunes L. A. O , Belançon M. P. , Rohling J. H. , Baesso M. L. , Malta O. L.
Published: October 2011

Energy transfer processes in Yb3+-Tb3+ co-doped, low-silica calcium aluminosilicate glasses were analyzed. Luminescence and time-resolved measurements were used to study upconversion processes, such as Yb-Tb cooperative sensitization, Yb-Yb cooperative luminescence, and Yb-Tb cross relaxation. The quantum cross relaxation efficiency was evaluated as a function on the Yb3+ concentration, and the maximum estimated value was approximately 51%. In addition, the intensity of the upconversion luminescence from the Tb3+:5D4 level decreased by two orders of magnitude comparing the value at room temperature with that at 123 K. As a consequence, Yb-Yb cooperative luminescence around 500 nm became comparable with the intensity of upconversion from the Tb3+:5D4 level. Furthermore, a dependence of the upconversion kinetics luminescence on temperature was observed. The upconversion rise time was constant and equal to 65 μs for temperatures between 296 to 473 K and decreased from 65 to 19 μs, without variation in the decay part, when the temperature was lowered from 296 to 123 K. These results were explained by a phonon-assisted cooperative sensitization process for the population of the Tb3+:5D4 level.