bluuebunny/crossref_metadata_2025 huggingface dataset:
Transient response of an annular interfacial crack between dissimilar piezoelectric layers under mechanical and electrical impacts
Authors: Ren J.H. , Wang W. , Li Y.S. , Cai Z.Y.
Published: February 2012

The dynamic response of an annular interfacial crack between dissimilar piezoelectric layers subjected to mechanical and electrical impact loadings is investigated. Laplace and Hankel transforms are employed to reduce the mixed boundary value problem to Cauchy singular integral equations. The integral equations are further reduced to a system of algebraic equations with the aid of Jacobi polynomials. The dynamic field intensity factors and dynamic energy release rates are determined. Numerical results reveal the effects of crack configuration, electrical impact loading on crack propagation, and growth.
Boundary layer separation of hydromagnetic flows
Authors: Núñez M.
Published: February 2012

The influence of the magnetic field on the boundary layer separation of a two‐dimensional incompressible flow of a conducting fluid subject to a non‐slip boundary condition is studied. It is found that the key factor differentiating this phenomenon from the hydrodynamic case is the angular velocity of the magnetic field at the boundary wall. The general equation governing the start of separation is illustrated by a class of flows generalizing the classical Hartmann one, where the physical meaning of the different terms is very clear.
Factorization of the Fourier transform of the pressure‐Poisson equation using finite differences in colocated grids
Authors: Mellado J.P. , Ansorge C.
Published: February 2012

The zero‐divergence constraint on the velocity field in the numerical simulation of incompressible flows can be reduced, in certain cases, to a set of one‐dimensional linear difference equations for the pressure. These equations involve the second‐order derivative δxδxp expressed in terms of twice the first‐order derivative. When implicit finite‐difference schemes are used, those equations lead to full linear systems, which are computationally prohibitive. Hence, it is a common practice to substitute δxδxp by a different discretization δxxp. However, it is well known that this step results in a non‐zero divergence in the velocity field. This paper presents a factorization of the original equation that allows to satisfy the discrete solenoidal constraint exactly while maintaining a linear relation between the number of operations and the grid size. As an example, the method is particularized to compact schemes often found in the literature.
Biocatalytic conversion of aloeresin A to aloesin
Authors: Steenkamp Lucia , Mathiba Kgama , Steenkamp Paul , Phehane Vuyisile , Mitra Robin , Heggie Steven , Brady Dean
Published: February 2012

Leaf exudates from Aloe species, such as the Southern African Aloe ferox, are used in traditional medicines for both humans and livestock. This includes aloesin, a skin bleaching product that inhibits the synthesis of melanin. Aloesin, (a C-glycoside-5-methylchromone) can be released from aloeresin A, an ester of aloesin, through hydrolysis. The objective of the current study was to identify an enzymatic hydrolysis method for converting aloeresin A to aloesin, resulting in increased concentrations of aloesin in the aloe bitters extract. More than 70 commercially available hydrolytic enzymes were screened for the conversion of aloeresin A. An esterase (ESL001-02) from Diversa, a lipase (Novozym 388) and a protease (Aspergillus oryzae) preparation were identified during screening as being capable of providing conversion of pure aloeresin A, with the protease giving the best conversion (~100%). It was found that a contaminating enzyme in Novo 388 was responsible for the conversion of aloeresin A to aloesin. This contaminating enzyme, possibly a protease, was able to give almost complete conversion using crude aloe bitters extract, doubling the concentration of aloesin in aloe bitters extract via the hydrolysis of aloeresin A.
A National Evaluation of Community‐Based Youth Cessation Programs: End of Program and Twelve‐Month Outcomes
Authors: Curry Susan J. , Mermelstein Robin J. , Emery Sherry L. , Sporer Amy K. , Berbaum Michael L. , Campbell Richard T. , Flay Brian , Warnecke Richard B.
Published: February 2012

Most youth cessation treatment research consists of efficacy studies in which treatments are evaluated under optimal conditions of delivery. Less is known about the effectiveness of youth cessation treatments delivered in real‐world, community based settings. A national sample of 41 community‐based youth cessation programs participated in a longitudinal evaluation to identify site, program, and participant characteristics associated with successful cessation. Validated quit rates were comparable to those in randomized controlled trials; 7‐day abstinence at the end of program averaged 14% and 30‐day abstinence at 12 months averaged 12%. Multivariate GEE models explored predictors of smoking cessation at the end of the programs and at 12 months. Results showed correlates of both short‐ and long‐term cessation. Findings point to the importance of both individual and community‐level variables, including motivation, opportunities for and encouragement to engage in activities outside of academics, having youth participate in treatment before they become highly dependent smokers, and community norms and ordinances that discourage youth purchase, use and possession of tobacco. Providing evidence‐based treatment to youth in community‐based settings results in successful cessation.
Investment and employment from large-scale photovoltaics up to 2050
Authors: Grossmann Wolf , Steininger Karl W. , Schmid Christoph , Grossmann Iris
Published: February 2012

Investments in renewable energy were at US$211 billion in 2010 and developing economies overtook developed ones for the first time in terms of new financial investments in renewable energy. Photovoltaics for generation of electricity from sunlight has the highest growth rate among the competing forms of renewable energy and has now begun to achieve grid parity in some regions. If these trends of investments continue, solar energy will play a major economic role. We analyze these developments and assess the ensuing amounts of investment and employment for a range of sizes of the sector of solar energy. We find that by 2050 electricity from photovoltaics could cover up to 90% of total global energy demand, with a then global capital investment in our main scenario in photovoltaic manufacturing capacity at 500 billion US$2010 by around 2030 and 1,500 billion by 2050. Employment in photovoltaic manufacturing is predicted to rise to 6 million by 2050. Sensitivity analysis with respect to the core parameters of assumptions is supplied.
On the reliability and availability of replicated and rejuvenating systems under stealth attacks and intrusions
Authors: Teixeira d’Aguiar Norton Brandão Luís , Neves Bessani Alysson
Published: February 2012

This paper considers the estimation of reliability and availability of intrusion-tolerant systems subject to non-detectable intrusions caused by stealth attacks. We observe that typical intrusion tolerance techniques may in certain circumstances worsen the dependability properties they were meant to improve. We model intrusions as a probabilistic effect of adversarial efforts and analyze different strategies of attack and rejuvenation. We compare several configurations of intrusion-tolerant replication and proactive rejuvenation, and varying mission times and expected times to node-intrusion. In doing so, we identify thresholds that distinguish between improvement and degradation of dependability, with a focus on security. We highlight the complementarity of replication and rejuvenation, showing improvements of resilience not attainable with any of the techniques alone, but possible when they are combined. We advocate the need for thorougher system models, by showing vulnerabilities arising from incomplete specifications.
Comparison Between Empirical Protein Force Fields for the Simulation of the Adsorption Behavior of Structured LK Peptides on Functionalized Surfaces
Authors: Collier Galen , Vellore Nadeem A. , Yancey Jeremy A. , Stuart Steven J. , Latour Robert A.
Published: February 2012

All-atom empirical molecular mechanics protein force fields, which have been developed to represent the energetics of peptide folding behavior in aqueous solution, have not been parameterized for protein interactions with solid material surfaces. As a result, their applicability for representing the adsorption behavior of proteins with functionalized material surfaces should not be assumed. To address this issue, we conducted replica-exchange molecular dynamics simulations of the adsorption behavior of structured peptides to functionalized surfaces using three protein force fields that are widely used for the simulation of peptide adsorption behavior: CHARMM22, AMBER94, and OPLS-AA. Simulation results for peptide structure both in solution and when adsorbed to the surfaces were compared to experimental results for similar peptide-surface systems to provide a means of evaluating and comparing the performance of these three force fields for this type of application. Substantial differences in both solution and adsorbed peptide conformations were found amongst these three force fields, with the CHARMM22 force field found to most closely match experimental results.
Petrogenesis and tectonic significance of the Late Permian–Middle Triassic calc-alkaline granites in the Balong region, eastern Kunlun Orogen, China
Authors: ZHANG JIN-YANG , MA CHANG-QIAN , XIONG FU-HAO , LIU BIN
Published: February 2012

Numerous calc-alkaline granitoid intrusions in the eastern Kunlun Orogen provide a valuable opportunity to constrain the evolution of the orogen. The age and genesis of these intrusions, however, remain poorly understood. The granitoid intrusions near the Balong region, eastern Kunlun Orogen, consist of granodiorite, diorite and syenogranite. The granodiorite contains crystallized segregations, abundant mafic microgranular enclaves (MMEs) and small quartz diorite stocks. In situ zircon U–Pb dating reveals that the granodiorites and quartz diorites were emplaced between 263 and 241 Ma, whereas the syenogranite was produced at c. 231 Ma. The granodiorite and quartz diorite have a calc-alkaline affinity and are metaluminous and Na-rich, with slightly enriched Sr–Nd isotope compositions. The granodiorite is characterized by fractionated REE patterns, whereas the quartz diorite displays a relatively flat REE pattern. The MMEs are consistent with the granodiorite in terms of incompatible elements and Sr–Nd isotope composition. Compared to the granodiorite and diorite, the syenogranite has higher SiO2, K, Rb, Th and Sr contents and a lower Rb/Sr ratio. The results presented here, when combined with regional geological data, indicate that the granodiorite and quartz diorite were derived from dehydration melting of mafic lower crustal rocks during the N-directed subduction of the Anyemaqen ocean lithosphere in Late Permian–Middle Triassic times, whereas the syenogranite was produced at a higher crustal level in a syn-collisional setting compared to the granodiorite.
Simulations of efficient laser wakefield accelerators from 1 to 100GeV
Authors: TZOUFRAS M. , HUANG C. , COOLEY J. H. , TSUNG F. S. , VIEIRA J. , MORI W. B.
Published: February 2012

Optimization of laser wakefield acceleration involves understanding and control of the laser evolution in tenuous plasmas, the response of the plasma medium, and its effect on the accelerating particles. We explore these phenomena in the weakly nonlinear regime, in which the laser power is similar to the critical power for self-focusing. Using Particle-In-Cell simulations with the code QuickPIC, we demonstrate that a laser pulse can remain focused in a plasma channel for hundreds of Rayleigh lengths and efficiently accelerate a high-quality electron beam to 100GeV (25GeV) in a single stage with average gradient 3.6GV/m (7.2GV/m).
The British Imperial Antarctic Expedition 1920–1922: Paradise Harbour, Antarctic Peninsula
Authors: Harrowfield David L.
Published: February 2012

On 12 January 1921 the British Imperial Antarctic Expedition 1920–1922 led by 27 year old Cambridge graduate John Lachlan Cope, arrived at Paradise Harbour situated west of Andvord Bay on the Danco Coast, Graham Land. The four-man party was landed by Norwegian whalers, on a small island with a promontory they named ‘Water-boat Point’ now Waterboat Point (64°49’S, 62°52’E), because of an abandoned water-boat there. Fortunately ready accommodation was available in the boat and to this were attached cases of provisions to form an improvised hut with an extension added before winter. Cope and Wilkins his deputy leader stayed just six weeks and after helping to build the hut, in effect abandoned the other two members of the expedition, Bagshawe and Lester. The two men voluntarily remained and in the belief that they would be paid, vigorously pursued a varied scientific programme. Although lacking essential items including certain scientific instruments, they were comparatively well off until relieved by Norwegian whalers in January 1922. The expedition that lasted one year and a day and was supported logistically by Norwegian whalers, became the smallest British expedition to overwinter in Antarctica and was the only expedition at that time. Bagshawe and Lester produced an impressive record of observations in meteorology, biology, oceanography, glaciology, botany and geology. In 1951 when Chile established Presidente González Videla Station, remains of the water-boat and hut were present, but today little evidence remains of the site destroyed by natural processes, human intervention and buried by guano. With exception of a few papers and chapters in books,Two men in the Antarctic(Bagshawe 1939) remains the definitive work on this generally forgotten expedition. For this paper primary resources have focused on original manuscripts. Although much material including financial records if indeed they existed, has been lost, surviving documents provide insights into the expedition. Reasons for the eventual loss of Bagshawe and Lester's field station are discussed.
Unequal Social Engagement for Older Adults: Constraints on Choice
Authors: Rozanova Julia , Keating Norah , Eales Jacquie
Published: February 2012

Bien que les associations positives entre l’engagement et le bien-être social dans la vie ultérieure ont été confirmées par certaines études, cette étude visait à comprendre pourquoi certaines personnes ainées ne peuvent pas être impliquées. Les auteurs ont analysé des expériences vécues de 89 ainés demeurant dans trois communautés rurales au Canada, raconté dans les entrevues demi-structuré, utilisant la méthode de comparaison constante. Cinq facteurs font des choix pour l’engagement social dans la vie ultérieure inégale parmi les personnes ainées qui diffèrent par le sexe, la classe, l’âge, et le statut de santé. L’engagement profond dans le travail de soin, l’altruisme obligatoire, les ressources personnelles, les occasions d’implication perçues objectivement et subjectivement disponibles, et les barrières ageistes autour des activités désirées comme le travail contraignent des choix pour les aînés qui manquent le privilège dans l’économie du marché, notamment pour les vieilles femmes à faibles revenus. Pour éviter nuire et stigmatiser les plus vieilles personnes vulnérables, les barrières sociales aux activités significatives doivent être abordées – par exemple, par la provision de sécurité de revenu ou renversant la discrimination en raison de l’âge dans l’accès au marché du travail.
A compiled implementation of normalisation by evaluation
Authors: AEHLIG KLAUS , HAFTMANN FLORIAN , NIPKOW TOBIAS
Published: February 2012

We present a novel compiled approach to Normalisation by Evaluation (NBE) for ML-like languages. It supports efficient normalisation of open λ-terms with respect to β-reduction and rewrite rules. We have implemented NBE and show both a detailed formal model of our implementation and its verification in Isabelle. Finally we discuss how NBE is turned into a proof rule in Isabelle.
The Concept of Autonomy and Its Role in Kantian Ethics
Authors: BRASSINGTON IAIN
Published: February 2012

Among bioethicists, and perhaps ethicists generally, the idea that we are obliged to respect autonomy is something of a shibboleth. Appeals to autonomy are commonly put to work to support legal and moral claims about the importance of consent, but they also feed a wider discourse in which the patient’s desires are granted a very high importance and medical paternalism is regarded as almost self-evidently indefensible.
What Is the Habermasian Perspective in Bioethics?
Authors: GUNSON DARRYL
Published: February 2012

The overarching question addressed in this article is whether there is something that might reasonably be called a Habermasian approach or perspective that bioethical enquiry might utilize.
Habermas, Human Agency, and Human Genetic Enhancement
Authors: HERISSONE-KELLY PETER
Published: February 2012

Recent developments in genomic science hold out the tantalizing prospect of soon being able to treat and prevent a wide variety of medical conditions through gene therapy. In time, it may be possible to use similar techniques not simply to combat disease but also to enhance, or improve on, normal human functioning.
On Moral Enhancement from a Habermasian Perspective
Authors: EHNI HANS-JOERG , AURENQUE DIANA
Published: February 2012

The human being’s mastery of itself, on which the self is founded, practically always involves the annihilation of the subject in whose service that mastery is maintained, because the substance which is mastered, suppressed, and disintegrated by self-preservation is nothing other than the living entity.
Professionalism Department
Authors: WICCLAIR MARK , BARNARD DAVID
Published: February 2012

In this issue of CQ, we are pleased to inaugurate a new Department, Professionalism, with an article by Jeffrey Blustein entitled “When Doctors Break the Rules: On the Ethics of Physician Noncompliance.” The article examines the ethical dilemmas physicians face when they believe that promoting the best interests of patients requires them to break one or more institutional rules.
Disgust in Bioethics
Authors: SALLES ARLEEN , DE MELO-MARTIN INMACULADA
Published: February 2012

“Dissecting Bioethics,” edited by Tuija Takala and Matti Häyry, welcomes contributions on the conceptual and theoretical dimensions of bioethics.

The section is dedicated to the idea that words defined by bioethicists and others should not be allowed to imprison people’s actual concerns, emotions, and thoughts. Papers that expose the many meanings of a concept, describe the different readings of a moral doctrine, or provide an alternative angle to seemingly self-evident issues are therefore particularly appreciated.

The themes covered in the section so far include dignity, naturalness, public interest, community, disability, autonomy, parity of reasoning, symbolic appeals, and toleration.

All submitted papers are peer reviewed. To submit a paper or to discuss a suitable topic, contact Tuija Takala attuija.takala@helsinki.fi.
The Case
Authors: MISHRA RUCHIKA
Published: February 2012

To submit a case that has been reviewed by an ethics committee or to submit papers on related topics in clinical ethics, readers are invited to contact Ruchika Mishra, editor of “Ethics Committees and Consultants at Work,” at: ruchika.mishra@gmail.com.
The Density Turán Problem
Authors: CSIKVÁRI PÉTER , NAGY ZOLTÁN LÓRÁNT
Published: February 2012

LetHbe a graph onnvertices and let the blow-up graphG[H] be defined as follows. We replace each vertexviofHby a clusterAiand connect some pairs of vertices ofAiandAjif (vi,vj) is an edge of the graphH. As usual, we define the edge density betweenAiandAjasWe study the following problem. Given densities γijfor each edge (i,j) ∈E(H), one has to decide whether there exists a blow-up graphG[H], with edge densities at least γij, such that one cannot choose a vertex from each cluster, so that the obtained graph is isomorphic toH,i.e., noHappears as a transversal inG[H]. We calldcrit(H) the maximal value for which there exists a blow-up graphG[H] with edge densitiesd(Ai,Aj)=dcrit(H) ((vi,vj) ∈E(H)) not containingHin the above sense. Our main goal is to determine the critical edge density and to characterize the extremal graphs.

First, in the case of treeTwe give an efficient algorithm to decide whether a given set of edge densities ensures the existence of a transversalTin the blow-up graph. Then we give general bounds ondcrit(H) in terms of the maximal degree. In connection with the extremal structure, the so-called star decomposition is proved to give the best construction forH-transversal-free blow-up graphs for several graph classes. Our approach applies algebraic graph-theoretical, combinatorial and probabilistic tools.
Associations of home food availability, dietary intake, screen time and physical activity with BMI in young American-Indian children
Authors: Arcan Chrisa , Hannan Peter J , Fulkerson Jayne A , Himes John H , Rock Bonnie Holy , Smyth Mary , Story Mary
Published: February 2012

Objective

To evaluate associations between home environmental factors and BMI of young American-Indian children.

Design

Cross-sectional and prospective study.

Setting

School-based obesity prevention trial (Bright Start) on a Northern Plains Indian reservation in South Dakota. Mixed model multivariable analysis was used to examine associations between child BMI categories (normal, overweight and obese) and home food availability, children's dietary intake and physical activity. Analyses were adjusted for age, gender, socio-economic status, parent BMI and school; prospective analyses also adjusted for study condition and baseline predictor and outcome variables.

Subjects

Kindergarten children (n 424, 51 % male; mean age = 5·8 years, 30 % overweight/obese) and parents/caregivers (89 % female; 86 % overweight/obese) had their height and weight measured and parents/caregivers completed surveys on home environmental factors (baseline and 2 years later).

Results

Higher fast-food intake and parent-perceived barriers to physical activity were marginally associated with higher probabilities of a child being overweight and obese. Vegetable availability was marginally associated with lower probabilities of being overweight and obese. The associations between home environmental factors and child weight status at follow-up were not significant.

Conclusions

Findings indicate that selected aspects of the home environment are associated with weight status of American-Indian children. Obesity interventions with this population should consider helping parents to engage and model healthful behaviours and to increase availability of healthful foods at home.
Fair Conditions and Fair Consequences? Exploring New Labour, Welfare Contractualism and Social Attitudes
Authors: Sage Daniel
Published: February 2012

This article explores the intention and effects of New Labour's ‘conditional’ welfare-to-work strategy. Conditionality has been the subject of substantive debate, with New Labour distinguishing its own contractualist welfare reforms from alternative strategies, often associated with ‘punitive’ US workfare. This article assesses whether New Labour's attempt to fashion what is described as ‘reciprocal responsibility’ in welfare arrangements avoided the commonly cited by-products of workfare. To achieve this, evidence is presented from the British Social Attitudes series, which shows a profound hardening of attitudes towards the unemployed. In light of these findings, the evidence supports arguments about the adverse effects that welfare contractualism can have for wider social relations.
Hot flow anomalies at Venus
Authors: Collinson G. A. , Sibeck D. G. , Masters A. , Shane N. , Slavin J. A. , Coates A. J. , Zhang T. L. , Sarantos M. , Boardsen S. , Moore T. E. , Barabash S.
Published: February 2012

We present a multi‐instrument study of a hot flow anomaly (HFA) observed by the Venus Express spacecraft in the Venusian foreshock, on 22 March 2008, incorporating both Venus Express Magnetometer and Analyzer of Space Plasmas and Energetic Atoms (ASPERA) plasma observations. Centered on an interplanetary magnetic field discontinuity with inward convective motional electric fields on both sides, with a decreased core field strength, ion observations consistent with a flow deflection, and bounded by compressive heated edges, the properties of this event are consistent with those of HFAs observed at other planets within the solar system.
Primary productivity, new productivity, and their relation to carbon flux during two Southern Ocean Gas Exchange tracer experiments
Authors: Lance Veronica P. , Strutton Peter G. , Vaillancourt Robert D. , Hargreaves Bruce R. , Zhang Jia‐Zhong , Marra John
Published: February 2012

Biological uptake rates of inorganic carbon and nitrate were measured during two sequential tracer release gas exchange experiments, together known as the Southern Ocean Gas Exchange Experiment (SO GasEx) in the southwest Atlantic sector of the Southern Ocean Antarctic Zone (51°N, 38°W). Primary productivity estimated from 14C incubations ranged from 26.7 to 47.2 mmol C m−2 d−1 in the first experiment (Patch 1) and 13.7 to 39.4 mmol C m−2 d−1 in the second experiment (Patch 2). Nitrate‐based productivity estimated from 15NO3 incubations ranged from 5.8 to 13.1 mmol C m−2 d−1 in Patch 1 and 1.9 to 7.1 mmol C m−2 d−1 in Patch 2. The average ratio of nitrate‐based productivity to primary productivity (approximating the f ratio) was 0.24 in Patch 1 and 0.15 in Patch 2. Chlorophyll concentrations for both patches were less than 1 mg m−3. Photochemical efficiency (Fv/Fm) was low (∼0.3) in Patch 1 and moderate (∼0.45) in Patch 2. Si(OH)4 concentrations were potentially limiting (<1 mmol m−3 for Patch 1 and ∼3 mmol m−3 for Patch 2), while NH4+ concentrations were elevated (∼1 mmol m−3 for Patch 1 and ∼2.2 mmol m−3 for Patch 2) compared with typical open ocean Antarctic Zone water. We hypothesize that Patch 1 productivity was regulated by the availability of Si(OH)4, while Patch 2 productivity was regulated by grazers. Primary production and nitrate‐based production (as a proxy for C export) determined here provide components for a mixed layer carbon budget from which the air‐sea flux of CO2 will be quantified.
Linking emissions of fossil fuel CO2 and other anthropogenic trace gases using atmospheric 14CO2
Authors: Miller John B. , Lehman Scott J. , Montzka Stephen A. , Sweeney Colm , Miller Benjamin R. , Karion Anna , Wolak Chad , Dlugokencky Ed J. , Southon John , Turnbull Jocelyn C. , Tans Pieter P.
Published: February 2012

Atmospheric CO2 gradients are usually dominated by the signal from net terrestrial biological fluxes, despite the fact that fossil fuel combustion fluxes are larger in the annual mean. Here, we use a six year long series of 14CO2 and CO2 measurements obtained from vertical profiles at two northeast U.S. aircraft sampling sites to partition lower troposphere CO2 enhancements (and depletions) into terrestrial biological and fossil fuel components (Cbio and Cff). Mean Cff is 1.5 ppm, and 2.4 ppm when we consider only planetary boundary layer samples. However, we find that the contribution of Cbio to CO2 enhancements is large throughout the year, and averages 60% in winter. Paired observations of Cff and the lower troposphere enhancements (Δgas) of 22 other anthropogenic gases (CH4, CO, halo‐ and hydrocarbons and others) measured in the same samples are used to determine apparent emission ratios for each gas. We then scale these ratios by the well known U.S. fossil fuel CO2 emissions to provide observationally based estimates of national emissions for each gas and compare these to “bottom up” estimates from inventories. Correlations of Δgas with Cff for almost all gases are statistically significant with median r2for winter, summer and the entire year of 0.59, 0.45, and 0.42, respectively. Many gases exhibit statistically significant winter:summer differences in ratios that indicate seasonality of emissions or chemical destruction. The variability of ratios in a given season is not readily attributable to meteorological or geographic variables and instead most likely reflects real, short‐term spatiotemporal variability of emissions.
Global contrail coverage simulated by CAM5 with the inventory of 2006 global aircraft emissions
Authors: Chen Chih‐Chieh , Gettelman Andrew , Craig Cheryl , Minnis Patrick , Duda David P.
Published: February 2012

This paper documents the incorporation of an inventory of the AEDT (Aviation Environmental Design Tool) global commercial aircraft emissions for the year of 2006 into the National Center for Atmospheric Research Community Earth System Model (CESM) version 1. The original dataset reports aircraft emission mass of ten species on an hourly basis which is converted to monthly emission mixing ratio tendencies as the released version of the dataset. We also describe how the released aircraft emission dataset is incorporated into CESM. A contrail parameterization is implemented in the CESM in which it is assumed that persistent contrails initially form when aircraft water vapor emissions experience a favorable atmospheric environment. Both aircraft emissions and ambient humidity are attributed to the formation of contrails. The ice water content of contrails is assumed to follow an empirical function of atmospheric temperature which determines the cloud fraction associated with contrails. Our modeling study indicates that the simulated global contrail coverage is sensitive to the vertical resolution of the GCMs in the upper troposphere and lower stratosphere because of model assumptions about the vertical overlap structure of clouds. Furthermore, the extent of global contrail coverage simulated by CESM exhibits a seasonal cycle which is in broad agreement with observations.
Radio Aurora Explorer: Mission science and radar system
Authors: Bahcivan H. , Cutler J. W.
Published: February 2012

The Radio Aurora Explorer (RAX) satellite is the first of several satellites funded under the NSF CubeSat‐based Space Weather and Atmospheric Research Program. RAX is a ground‐to‐space bi‐static radar remote sensing experiment designed to measure and understand the causes of meter‐scale ionospheric irregularities. Also known as field‐aligned irregularities (FAI), such non‐thermal, coherent fluctuations of electron density occur in response to strong ionospheric flows or plasma density gradients during geomagnetic disturbances and are considered a space weather concern due to disruption to communication and navigation signals. The RAX CubeSat was launched in November 2010 and conducted a single experiment in coordination with the Poker Flat Incoherent Scatter Radar. Due to geophysical inactivity, e.g., lack of strong ionospheric electric fields and low ionospheric densities, no FAI were expected or observed. However, the radar receiver payload operation was successfully demonstrated, including the capability to sense signals as low as −110 dBm, the capability of transmitter–receiver synchronization and accurate ranging, processing of 1.2 GB of raw radar data on board in less than 1 hour, and the downlink of the science results within three–four passes. Analysis of the payload data shows that the noise level is sufficiently low. Although the interference level is a concern, it does not appear to significantly limit the measurements. Toward the end of December 2010, the solar power system gradually degraded and the mission terminated in early February 2011 after prolonged loss of contact with the satellite. Meanwhile, RAX II was launched in October 2011 to a polar orbit. This paper describes the RAX science and radar system and presents the results from the first experiment conducted.
Parameter estimation by ensemble Kalman filters with transformed data: Approach and application to hydraulic tomography
Authors: Schöniger A. , Nowak W. , Hendricks Franssen H.‐J.
Published: February 2012

Ensemble Kalman filters (EnKFs) are a successful tool for estimating state variables in atmospheric and oceanic sciences. Recent research has prepared the EnKF for parameter estimation in groundwater applications. EnKFs are optimal in the sense of Bayesian updating only if all involved variables are multivariate Gaussian. Subsurface flow and transport state variables, however, generally do not show Gaussian dependence on hydraulic log conductivity and among each other, even if log conductivity is multi‐Gaussian. To improve EnKFs in this context, we apply nonlinear, monotonic transformations to the observed states, rendering them Gaussian (Gaussian anamorphosis, GA). Similar ideas have recently been presented by Béal et al. (2010) in the context of state estimation. Our work transfers and adapts this methodology to parameter estimation. Additionally, we address the treatment of measurement errors in the transformation and provide several multivariate analysis tools to evaluate the expected usefulness of GA beforehand. For illustration, we present a first‐time application of an EnKF to parameter estimation from 3‐D hydraulic tomography in multi‐Gaussian log conductivity fields. Results show that (1) GA achieves an implicit pseudolinearization of drawdown data as a function of log conductivity and (2) this makes both parameter identification and prediction of flow and transport more accurate. Combining EnKFs with GA yields a computationally efficient tool for nonlinear inversion of data with improved accuracy. This is an attractive benefit, given that linearization‐free methods such as particle filters are computationally extremely demanding.
Ground referencing GRACE satellite estimates of groundwater storage changes in the California Central Valley, USA
Authors: Scanlon B. R. , Longuevergne L. , Long D.
Published: February 2012

There is increasing interest in using Gravity Recovery and Climate Experiment (GRACE) satellite data to remotely monitor groundwater storage variations; however, comparisons with ground‐based well data are limited but necessary to validate satellite data processing, especially when the study area is close to or below the GRACE footprint. The Central Valley is a heavily irrigated region with large‐scale groundwater depletion during droughts. Here we compare updated estimates of groundwater storage changes in the California Central Valley using GRACE satellites with storage changes from groundwater level data. A new processing approach was applied that optimally uses available GRACE and water balance component data to extract changes in groundwater storage. GRACE satellites show that groundwater depletion totaled ∼31.0 ± 3.0 km3 for Groupe de Recherche de Geodesie Spatiale (GRGS) satellite data during the drought from October 2006 through March 2010. Groundwater storage changes from GRACE agreed with those from well data for the overlap period (April 2006 through September 2009) (27 km3 for both). General correspondence between GRACE and groundwater level data validates the methodology and increases confidence in use of GRACE satellites to monitor groundwater storage changes.
On the reported ionospheric precursor of the 1999 Hector Mine, California earthquake
Authors: Thomas J. N. , Love J. J. , Komjathy A. , Verkhoglyadova O. P. , Butala M. , Rivera N.
Published: February 2012

Using Global Positioning System (GPS) data from sites near the 16 Oct. 1999 Hector Mine, California earthquake, Pulinets et al. (2007) identified anomalous changes in the ionospheric total electron content (TEC) starting one week prior to the earthquake. Pulinets (2007) suggested that precursory phenomena of this type could be useful for predicting earthquakes. On the other hand, and in a separate analysis, Afraimovich et al. (2004) concluded that TEC variations near the epicenter were controlled by solar and geomagnetic activity that were unrelated to the earthquake. In an investigation of these very different results, we examine TEC time series of long duration from GPS stations near and far from the epicenter of the Hector Mine earthquake, and long before and long after the earthquake. While we can reproduce the essential time series results of Pulinets et al., we find that the signal they identified as being anomalous is not actually anomalous. Instead, it is just part of normal global‐scale TEC variation. We conclude that the TEC anomaly reported by Pulinets et al. is unrelated to the Hector Mine earthquake.
pH as a Biomarker of Neurodegeneration in Huntington's Disease: A Translational Rodent-Human MRS Study
Authors: Chaumeil Myriam M , Valette Julien , Baligand Céline , Brouillet Emmanuel , Hantraye Philippe , Bloch Gilles , Gaura Véronique , Rialland Amandine , Krystkowiak Pierre , Verny Christophe , Damier Philippe , Remy Philippe , Bachoud-Levi Anne-Catherine , Carlier Pierre , Lebon Vincent
Published: February 2012

Early diagnosis and follow-up of neurodegenerative diseases are often hampered by the lack of reliable biomarkers. Neuroimaging techniques like magnetic resonance spectroscopy (MRS) offer promising tools to detect biochemical alterations at early stages of degeneration. Intracellular pH, which can be measured noninvasively by 31P-MRS, has shown variations in several brain diseases. Our purpose has been to evaluate the potential of MRS-measured pH as a relevant biomarker of early degeneration in Huntington's disease (HD). We used a translational approach starting with a preclinical validation of our hypothesis before adapting the method to HD patients. 31P-MRS-derived cerebral pH was first measured in rodents during chronic intoxication with 3-nitropropionic acid (3NP). A significant pH increase was observed early into the intoxication protocol (pH = 7.17 ± 0.02 after 3 days) as compared with preintoxication (pH = 7.08 ± 0.03). Furthermore, pH changes correlated with the 3NP-induced inhibition of succinate dehydrogenase and preceded striatum lesions. Using a similar MRS approach implemented on a clinical MRI, we then showed that cerebral pH was significantly higher in HD patients ( n = 7) than in healthy controls ( n = 6) (7.05 ± 0.03 versus 7.02 ± 0.01, respectively, P = 0.026). Altogether, both preclinical and human data strongly argue in favor of MRS-measured pH being a promising biomarker for diagnosis and follow-up of HD.
Interruption, Reproduction and Genealogies of ‘Staying Put’ in Diaspora Space
Authors: Gedalof Irene
Published: February 2012

In her 1999 article ‘The Scent of Memory’, Avtar Brah maps the ways in which gendered, classed and racialised identities and subjectivities are produced in the diaspora space of Britain. ‘The Scent of Memory’ begins, repeatedly returns to and ends with the figure of a mother — Jean, a white English woman in the Southall of the 1970s and 1980s. One way of reading this article is as a series of interruptions, each of which allows us to see Jean differently, to replace her in what Brah has memorably termed the entanglement of genealogies of dispersion with those of staying put (Brah, 1996: 181). In this article, I stage my own set of speculative interruptions, through which recent feminist theorising of maternal subjectivities confronts the ways in which the maternal and the reproductive are conceptualised, metaphorised and mobilised in contemporary accounts of community cohesion, Britishness and belonging. At stake is our ability to challenge those still-dominant discourses that naturalise repetition and sameness as the necessary ground of belonging, obscuring and ignoring the gendered, racialised and other differences that mark Britishness, and which thereby reproduce the migrant and the minoritised as a problem for the stability of British identities. Following on from and extending Lisa Baraitser's claim that thinking about the relationship with the other ‘might just as well start with the mother’ (2009a: 153), I ask whether rethinking the reproductive can enable a more complex account of the ways in which ‘the native’ is transformed in diaspora spaces.
Working-Class Whiteness from within and Without: An Auto-Ethnographic Response to Avtar Bran's ‘The Scent of Memory’
Authors: Thomas Lyn
Published: February 2012

Inspired by and responding to Avtar Brah's ‘The Scent of Memory’, this piece attempts to reinscribe race into an auto-ethnographic narrative where previously whiteness was unmarked. It explores the dynamics of gender, race and class through the author's personal history as a white English woman and class migrant, and through discussion of the broader political and historical context of that trajectory. The discussion includes analysis of the impact of British Conservative politician Enoch Powell's infamous ‘rivers of blood’ speech in 1968 on the author's white English working-class culture of origin in Wolverhampton, where Powell was a Member of Parliament. The article considers the speech's continuing ramifications in the twenty-first century and in more middle-class contexts, as evidenced by the recent evocation of the speech by historian David Starkey in discussion of the ‘riots’ of August 2011 in British cities. The personal history is reconstructed through a series of memory scenes that trace and retrace the author's experience and understanding of race and its intersections with class and gender; this is attempted in full cognisance of the constructed nature of memory, and of the performance of identity that autobiography entails. The piece draws on the work of the class migrant white French writer Annie Ernaux, with whom the author has been in dialogue since 1997.
Racialisation, Relationality and Riots: Intersections and Interpellations
Authors: Phoenix Aisha , Phoenix Ann
Published: February 2012

This paper takes up Avtar Brah's (1999) invitation to write back to the issues she raises in her mapping of the production of gendered, classed and racialised subjectivities in west London. It addresses two topics that, together, illuminate racialised and gendered interpellation and psychosocial processes. The paper is divided into two main sections. The first draws on empirical research on the transition to motherhood conducted in east London to consider one mother's experience of giving birth in the local maternity hospital. The maternity ward constituted a site where racialised difference became salient, leading her to construct her maternal identity by asserting her difference from Bangladeshi mothers and so self-racialising, as well as ‘othering’ Bangladeshi mothers. The paper analyses the ways in which her biography may help to explain why her experience of the maternity hospital interpellates her into racialised positioning. The second section focuses on media responses to the riots in various English cities in August 2011. It examines the ways in which some media punditry racialised the riots and inclusion in the British postcolonial nation. The paper analyses three sets of commentaries and illuminates the ways in which they racialise the debate in essentialising ways, reproducing themes that were identified in the 1980s as ‘new racism’ and apportioning blame for the riots to ‘black gangster culture’. While these media pronouncements focus on racialisation, they are intersectional in implicitly also invoking gender and social class. The paper argues that the understanding of the mother's self-racialisation is deepened by a consideration of the racialised discourses that can be evoked (and are contested) in periods of social unrest. The paper thus draws on part of the methodology of ‘The Scent of Memory’ in layering media readings and biographical narratives to analyse the contemporary psychosocial space of racialisation.
Avtar Brah's Cartographies: Moment, Method, Meaning
Authors: Hall Stuart
Published: February 2012

The following draws out a few points that suggest an inner coherence in the midst of the rich diversity of questions Avtar Brah addresses. One critical factor is that Brah's work appears at a specific historical ‘moment’ — a simultaneously political, historical and theoretical conjuncture — the diasporic. The diaspora — as an emergent space and an interpretive frame — unpicks the claims made for the unities of culturally homogeneous, racially purified identities, and constitutes the moment of the problematic of the subject — when critical thought comes face to face with the perplexing interface between the social and the psychic. Brah confronts the necessarily complex and contradictory specificities of differentiated subjectivities in the diasporic frame within a distinct ‘methodology’ — analytic and interpretive. The very structures ‘out there’, which have so often been thought of as determining, are understood as themselves providing frameworks of meaning, as having an internal psychic and discursive dimension. Avtar Brah is one of the few who have begun to capture such a double inscription through ongoing research. Such is particularly evident in ‘The Scent of Memory’, and it is through a reading of that essay that Brah's distinct ‘methodology’ is presented — an approach which is sensitive to the always already contradictory condition of ‘reality’. What I suggest of Brah's ‘methodology’ is that it is a practice that has significant consequences for the meaning and value placed on social contexts, for the ‘presence’ and ‘absence’ of information and knowledge in interpretation and analysis, a practice that we might call diasporic reasoning.
Mediations on Making Aaj Kaal
Authors: Puwar Nirmal
Published: February 2012

This article excavates a discussion on the mediations that informed the making of the film Aaj Kaal by Asian elders, in a project directed by Avtar Brah and coordinated by Jasbir Panesar with the film trainer Vipin Kumar. It brings this largely unknown and inventive film to the foreground of current developments in participative media research practices. The discussion explores the coming together of the ethnographic imagination and performative pedagogies during the course of an adult education community project centred on South Asian elders making a film. Collaborative dialogic encounters illuminate post-war British front rooms, the seaside and public spheres from what is usually an unlikely vantage point of view in public accounts.
The Scent of Memory: Strangers, Our Own and Others
Authors: Brah Avtar
Published: February 2012

Using, as a point of departure, Tim Lott's recent autobiography where he attempts to make sense of his mother's suicide of 1988 through a reconstruction of his family genealogy, this article tries to map the production of gendered, classed, and racialized subjects and subjectivity in west London. It addresses the tension between Lott's discourse of his own white working-class boyhood during the 1970s where questions of ‘race’ are all but absent, and the racialized ‘commonsense’ that pervades the interviews with other local white contemporaries of Lott and his parents. These narratives are analysed in relation to the socio-economic context and the political activism of the period. Theoretically, it analyses the ‘diaspora space’ of London/Britain, interrogating essentialist ‘origin stories’ of belonging; reaching out to a glimmer on the horizon of emerging non-identical formations of kinship across boundaries of class, racism and ethnicity; and exploring the purchase of certain South Asian terms – ‘ajnabi’, ‘ghair’ and ‘apna/apni’ – in constructing a nonbinarized understanding of identification across ‘difference’.
Two-Dimensional Coordination Polymers in Rubidium and Caesium Complexes with Orthanilic Acid
Authors: Smith Graham
Published: February 2012

The crystal structures of the rubidium and caesium complexes with 2-aminobenzenesulfonic acid (orthanilic acid), [Rb4(C6H6NO3S)4(H2O)]n(1) and [Cs(C6H6NO3S)]n(2), have been determined at 200 K. Complex 1 has a repeating unit comprising four independent and different Rb coordination centres, (RbO8), (RbO7), (RbN2O4) and (RbO10), each having irregular stereochemistry and involving several bidentate chelate sulfonate-O,O′-metal and bridging interactions, giving a two-dimensional polymeric layered structure. Anhydrous complex 2 is also polymeric with the irregular (CsO7) coordination polyhedron comprising six sulfonate oxygen donors from three separate bidentate chelate sulfonate ligands and one monodentate bridging sulfonate oxygen, giving a two-dimensional layered structure.