bluuebunny/crossref_metadata_2025 huggingface dataset:
Extending methods for investigating the relationship between treatment effect and baseline risk from pairwise meta‐analysis to network meta‐analysis
Authors: Achana Felix A. , Cooper Nicola J. , Dias Sofia , Lu Guobing , Rice Stephen J. C. , Kendrick Denise , Sutton Alex J.
Published: August 2012

Baseline risk is a proxy for unmeasured but important patient‐level characteristics, which may be modifiers of treatment effect, and is a potential source of heterogeneity in meta‐analysis. Models adjusting for baseline risk have been developed for pairwise meta‐analysis using the observed event rate in the placebo arm and taking into account the measurement error in the covariate to ensure that an unbiased estimate of the relationship is obtained. Our objective is to extend these methods to network meta‐analysis where it is of interest to adjust for baseline imbalances in the non‐intervention group event rate to reduce both heterogeneity and possibly inconsistency. This objective is complicated in network meta‐analysis by this covariate being sometimes missing, because of the fact that not all studies in a network may have a non‐active intervention arm. A random‐effects meta‐regression model allowing for inclusion of multi‐arm trials and trials without a ‘non‐intervention’ arm is developed. Analyses are conducted within a Bayesian framework using the WinBUGS software. The method is illustrated using two examples: (i) interventions to promote functional smoke alarm ownership by households with children and (ii) analgesics to reduce post‐operative morphine consumption following a major surgery. The results showed no evidence of baseline effect in the smoke alarm example, but the analgesics example shows that the adjustment can greatly reduce heterogeneity and improve overall model fit. Copyright © 2012 John Wiley & Sons, Ltd.
Sample size planning for survival prediction with focus on high‐dimensional data
Authors: Götte Heiko , Zwiener Isabella
Published: August 2012

Sample size planning should reflect the primary objective of a trial. If the primary objective is prediction, the sample size determination should focus on prediction accuracy instead of power. We present formulas for the determination of training set sample size for survival prediction. Sample size is chosen to control the difference between optimal and expected prediction error. Prediction is carried out by Cox proportional hazards models. The general approach considers censoring as well as low‐dimensional and high‐dimensional explanatory variables. For dimension reduction in the high‐dimensional setting, a variable selection step is inserted. If not all informative variables are included in the final model, the effect estimates are biased towards zero. The bias affects the prediction error, and its magnitude is influenced by the sample size. For variable selection, we consider two approaches: least absolute shrinkage and selection operator (LASCO) and univariable selection. For univariable selection, we can calculate input parameters for the sample size formula. For the LASCO, supportive simulations are necessary to appropriately choose the input parameters. We investigate the performance of the proposed formulas with the use of simulations. Simulation results support the validity of the sample size formulas. An application of a real data example illustrates the practical implementation of the method. Copyright © 2012 John Wiley & Sons, Ltd.
Synergistic Targeting of Cancer and Associated Angiogenesis Using Triple‐Targeted Dual‐Drug Silica Nanoformulations for Theragnostics
Authors: Veeranarayanan Srivani , Poulose Aby Cheruvathoor , Mohamed M. Sheikh , Varghese Saino Hanna , Nagaoka Yutaka , Yoshida Yasuhiko , Maekawa Toru , Kumar D. Sakthi
Published: August 2012

The targeting and therapeutic efficacy of dye‐ and dual‐drug‐loaded silica nanoparticles, functionalized with triple targeting ligands specific towards cancer and neoangiogenesis simultaneously, are discussed. This synergized, high‐precision, multitarget concept culminates in an elevated uptake of nanoparticles by cancer and angiogenic cells with amplified proficiency, thereby imparting superior therapeutic efficacy against breast cancer cells and completely disabling the migration and angiogenic sprouting ability of activated endothelial cells. The exceptional multimodal efficiency achieved by this single therapeutic nanoformulation holds promise for the synergistic targeting and treatment of the yet elusive cancer and its related angiogenesis in a single, lethal shot.
Screening Conditions for Rationally Engineered Electrodeposition of Nanostructures (SCREEN): Electrodeposition and Applications of Polypyrrole Nanofibers using Microfluidic Gradients
Authors: Burgoyne Hayden A. , Kim Philseok , Kolle Mathias , Epstein Alexander K. , Aizenberg Joanna
Published: August 2012

A rapid screening method for optimizing electrochemical deposition conditions of polypyrrole (PPy) nanostructures is reported. An electrochemical cell is integrated within a low‐cost microfluidic system, in which electrochemical deposition is carried out across a linear concentration gradient of a reaction parameter. The protocol, refered to as the screening of conditions for rationally engineered electrodeposition of nanostructures (SCREEN), allows rapid screening of conditions for the production of specific morphologies by characterizing the electrodeposited samples produced within a chemical gradient. To demonstrate the utility of the SCREEN method, applications in tunable optical coatings and superhydrophobic surfaces are presented.
Disease Modeling Using Embryonic Stem Cells: MeCP2 Regulates Nuclear Size and RNA Synthesis in Neurons
Authors: Yazdani Morteza , Deogracias Rubén , Guy Jacky , Poot Raymond A. , Bird Adrian , Barde Yves-Alain
Published: August 2012

Mutations in the gene encoding the methyl-CpG-binding protein MECP2 are the major cause of Rett syndrome, an autism spectrum disorder mainly affecting young females. MeCP2 is an abundant chromatin-associated protein, but how and when its absence begins to alter brain function is still far from clear. Using a stem cell-based system allowing the synchronous differentiation of neuronal progenitors, we found that in the absence of MeCP2, the size of neuronal nuclei fails to increase at normal rates during differentiation. This is accompanied by a marked decrease in the rate of ribonucleotide incorporation, indicating an early role of MeCP2 in regulating total gene transcription, not restricted to selected mRNAs. We also found that the levels of brain-derived neurotrophic factor (BDNF) were decreased in mutant neurons, while those of the presynaptic protein synaptophysin increased at similar rates in wild-type and mutant neurons. By contrast, nuclear size, transcription rates, and BDNF levels remained unchanged in astrocytes lacking MeCP2. Re-expressing MeCP2 in mutant neurons rescued the nuclear size phenotype as well as BDNF levels. These results reveal a new role of MeCP2 in regulating overall RNA synthesis in neurons during the course of their maturation, in line with recent findings indicating a reduced nucleolar size in neurons of the developing brain of mice lacking Mecp2.
TBX3 Promotes Human Embryonic Stem Cell Proliferation and Neuroepithelial Differentiation in a Differentiation Stage-Dependent Manner
Authors: Esmailpour Taraneh , Huang Taosheng
Published: August 2012

T-box 3 (Tbx3) is a member of the T-box family of genes. Mutations that result in the haploinsufficiency of TBX3 cause ulnar mammary syndrome in humans characterized by mammary gland hypoplasia as well as other congenital defects. In mice, homozygous mutations are embryonic lethal, suggesting that Tbx3 is essential for embryo development. Studies in mice have shown that Tbx3 is essential in the maintenance of mouse embryonic stem cell (ESC) self-renewal and in their differentiation into extraembryonic endoderm (ExEn). The role TBX3 plays in regulating human ESCs (hESCs) has not been explored. Since mouse and hESCs are known to represent distinct pluripotent states, it is important to address the role of TBX3 in hESC self-renewal and differentiation. Using overexpression and knockdown strategies, we found that TBX3 overexpression promotes hESC proliferation possibly by repressing the expression of both NFκBIB and p14ARF, known cell cycle regulators. During differentiation, TBX3 knockdown resulted in decreased neural rosette formation and in decreased expression of neuroepithelial and neuroectoderm markers (PAX6, LHX2, FOXG1, and RAX). Taken together, our data suggest a role for TBX3 in hESC proliferation and reveal an unrecognized novel role of TBX3 in promoting neuroepithelial differentiation. Our results suggest that TBX3 plays distinct roles in regulating self-renewal and differentiation in both hESCs and mouse ESCs.
p‐TCOs für Transparente Elektronik
Authors: Schulz Christina , Ulrich Stephan , Szyszka Bernd
Published: August 2012

In diesem Artikel werden neue Arten von Halbleitermaterialien vorgestellt. Transparente leitfähige Schichten gibt es in unserem Alltag schon sehr lange, allerdings ist der bisherige Typ der sogenannten „TCOs”︁ von Elektronenleitung dominiert. Um transparente p‐n‐Übergänge und damit transparente Elektronik herzustellen, fehlt bisher der transparente p‐Halbleiter. Forscher haben verschiedenste Ansätze gefunden, um diese neue Generation von Materialien herzustellen. Auch am Fraunhofer Institut für Schicht‐ und Oberflächentechnik (IST) in Braunschweig können diese Dünnschichten nunmehr produziert werden.
Spatio‐temporal propagation of wind power prediction errors
Authors: Girard Robin , Allard Denis
Published: August 2012

The increasing concentration of wind farms in some parts of the world calls for a new descriptive framework of power fluctuation that can summarize spatio‐temporal characteristics of the wind power production process. In the mean time, this high number of measurement devices has great potential for informing or alerting about upcoming front or phase errors. In this paper, we shed light on the spatio‐temporal characteristics of wind power forecast errors. We justify and use two strategies for obtaining the main direction and the speed of propagation. The first of these relies on an analysis of the local maxima of the correlation structure, and the second builds upon a planar wave modeling. The connection is made with meteorological parameters. Our analysis is presented so as to be easily reproducible in other cases. Copyright © 2012 John Wiley & Sons, Ltd.
Graphene nanostructures toward clean energy technology applications
Authors: Zhang Xianfeng , Wang Bin , Sunarso Jaka , Liu Shaomin , Zhi Linjie
Published: August 2012

Graphene, a one‐atom‐layer‐thick carbon‐structured material, has attracted global research attention due to its unique two‐dimensional structure, high electrical conductivity, superior electron‐transfer properties and charge‐carrier charge‐carrier mobility, large specific surface area, high transparency, and good mechanical properties. After its successful isolation into the free standing form in 2004, various graphene nanostructures have been developed and incorporated as key components in supercapacitors, lithium‐ion batteries, solar cells, and fuel cells; the energy supporting devices which hold the key role to sustain our energy demand well into the future. Herein, we summarized the recent progress and performance of these graphene–nanostructure‐based devices.

This article is categorized under:

Energy Infrastructure > Science and Materials

Energy and Development > Science and Materials

Energy Research & Innovation > Science and Materials
Synthesis and Structures of Dinuclear Copper(I) and Silver(I) 1, 3‐Bis[(2‐chloro)benzene]triazenide Complexes
Authors: Cai Zhan‐Mao , Yu Gang , Lv Qi‐Ying , Jiang Wen‐Qing , Zhan Shu‐Zhong
Published: August 2012

In the presence of Et3N, the reaction of 1, 3‐bis[(2‐chloro)benzene]triazene (HL) with CuCl or AgNO3 gives the triazenide complexes {Cu2(L)2} (1) and {Ag2(L)2} (2), respectively. The X‐ray crystal structures of both complexes were obtained. The metal–metal distances (Cu···Cu and Ag···Ag) are 2.4974(5) and 2.7208(5) Å, respectively.
Copper(II) and Cadmium(II) Complexes Based on N,N‐Bis(3, 5‐dimethyl‐2‐hydroxybenzyl)‐N‐(2‐pyridylmethyl)amine Ligand: Syntheses, Structures, Magnetic, and Luminescent Properties
Authors: Yang Lijuan , Chen Wenqian , Chen Yanmei , Liu Wei , Lei Tao , Li Lei , Lin Miaoshui , Wu Jian , Cao Yanyuan , Li Wu , Li Yahong
Published: August 2012

The reaction of the aryl‐oxide ligand H2L [H2L = N,N‐bis(3, 5‐dimethyl‐2‐hydroxybenzyl)‐N‐(2‐pyridylmethyl)amine] with CuSO4·5H2O, CuCl2·2H2O, CuBr2, CdCl2·2.5H2O, and Cd(OAc)2·2H2O, respectively, under hydrothermal conditions gave the complexes [Cu(H2L1)2]·SO4·3CH3OH (1), [Cu2(H2L2)2Cl4] (2), [Cu2(H2L2)2Br4] (3), [Cd2(HL)2Cl2] (4), and [Cd2(L)2(CH3COOH)2]·H2L (5), where H2L1 [H2L1 = 2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenol] and H2L2 [H2L2 = 2‐(2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenoxy)‐4, 6‐dimethylphenol] were derived from the solvothermal in situ metal/ligand reactions. These complexes were characterized by IR spectroscopy, elementary analysis, and X‐ray diffraction. A low‐temperature magnetic susceptibility measurement for the solid sample of 2 revealed antiferromagnetic interactions between two central copper(II) atoms. The emission property studies for complexes 4 and 5 indicated strong luminescence emission.
Alleviating the non-ultralocality of coset σ-models through a generalized Faddeev-Reshetikhin procedure
Authors: Delduc F. , Magro M. , Vicedo B.
Published: August 2012

Abstract

The Faddeev-Reshetikhin procedure corresponds to a removal of the non-ultralocality of the classical SU(2) principal chiral model. It is realized by defining another field theory, which has the same Lax pair and equations of motion but a different Poisson structure and Hamiltonian. Following earlier work of M. Semenov-Tian-Shansky and A. Sevostyanov, we show how it is possible to alleviate in a similar way the non-ultralocality of symmetric space σ-models. The equivalence of the equations of motion holds only at the level of the Pohlmeyer reduction of these models, which corresponds to symmetric space sine-Gordon models. This work therefore shows indirectly that symmetric space sine-Gordon models, defined by a gauged Wess-Zumino-Witten action with an integrable potential, have a mild non-ultralocality. The first step needed to construct an integrable discretization of these models is performed by determining the discrete analogue of the Poisson algebra of their Lax matrices.
Surgical and Anesthesia Capacity in Bolivian Public Hospitals: Results from a National Hospital Survey
Authors: LeBrun Drake G. , Saavedra‐Pozo Iracema , Agreda‐Flores Fernando , Burdic MacKenzie L. , Notrica Michelle R. , McQueen K. A. Kelly
Published: August 2012

Background

Underdeveloped nations suffer from significant deficiencies in surgical and anesthesia care. Although surgical inequities are a pressing issue internationally, the extent of these inequities is unknown due to a lack of data. The aim of this study was to assess surgical and anesthesia capacity in Bolivia as part of a multinational study assessing surgical and anesthesia infrastructure in Africa, Latin America, and South Asia.

Methods

A standardized survey tool was used to obtain national‐level health‐care data at the Bolivian Ministry of Health. Hospital‐specific data were obtained through interviews with key administrators and providers at 18 public basic and general hospitals in Bolivia.

Results

There are 1,270 obstetrician/gynecologists and 1,807 surgeons in Bolivia. In contrast, there are 500 anesthesiologists, placing a large anesthesia burden on the country. Basic hospitals and general hospitals performed an average of 730 and 2,858 operations per year, respectively. One basic hospital was unable to perform any surgeries due to a lack of surgical manpower. All but two hospitals reported some lack of infrastructure, equipment, or pharmaceutical capacity. The ability to collect health outcomes was inconsistent in most hospitals.

Conclusions

Surgical capacity varies throughout Bolivia. There are relatively large numbers of surgery providers but an insufficient number of anesthesiologists, suggesting a specific need for further development in anesthesia. Though there are many areas of strength within the Bolivian public health‐care system, this survey identified several areas to which national policy and international collaboration can contribute in order to more adequately address major causes of surgical morbidity and mortality.
Using Community Surveys to Inform the Planning and Implementation of Environmental Change Strategies: Participatory Research in 12 Washington Communities
Authors: Gabriel Roy M. , Leichtling Gillian J. , Bolan Marc , Becker Linda G.
Published: August 2012

A number of studies have demonstrated the efficacy of environmental change strategies (ECS) in effecting community‐level change on attitudes and behaviors related to underage drinking (Treno and Lee in Alcohol Res Health 26:35–40, 2002; Birckmayer et al. in J Drug Educ 34(2):121–153, 2004). Primary data collection to inform the design of these strategies, however, can be resource intensive and exceed the capacity of community stakeholders. This study describes the participatory planning and implementation of community‐level surveys in 12 diverse communities in the state of Washington. These surveys were conducted through collaborations among community volunteers and evaluation experts assigned to each community. The surveys were driven by communities’ prevention planning needs and interests; constructed from collections of existing, field‐tested items and scales; implemented by community members; analyzed by evaluation staff; and used in the design of ECS by community‐level leaders and prevention practitioners. The communities varied in the content of their surveys, in their sampling approaches and in their data collection methods. Although these surveys were not conducted using traditional rigorous population survey methodology, they were done within limited resources, and the participatory nature of these activities strengthened the communities’ commitment to using their results in the planning of their environmental change strategies.
Neonatal nociception elevated baseline blood pressure and attenuated cardiovascular responsiveness to noxious stress in adult rats
Authors: Chu Ya‐Chun , Yang Cheryl C.H. , Lin Ho‐Tien , Chen Pin‐Tarng , Chang Kuang‐Yi , Yang Shun‐Chin , Kuo Terry B.J.
Published: August 2012

Neonatal nociception has significant long‐term effects on sensory perception in adult animals. Although neonatal adverse experience affect future responsiveness to stressors is documented, little is known about the involvement of early nociceptive experiences in the susceptibility to subsequent nociceptive stress exposure during adulthood. The aim of this study is to explore the developmental change in cardiovascular regulating activity in adult rats that had been subjected to neonatal nociceptive insults. To address this question, we treated neonatal rats with an intraplantar injection of saline (control) or carrageenan at postnatal day 1. The carrageenan‐treated rats exhibited generalized hypoalgesia at basal state, and localized hyperalgesia after re‐nociceptive challenge induced by intraplantar injections of complete Freund's adjuvant (CFA) as adults. Then we recorded baseline cardiovascular variables and 24‐h responsiveness to an injection of CFA in the free‐moving adult rats with telemetric technique.

The carrageenan‐treated rats showed significantly higher basal blood pressures (110.3 ± 3.16 vs. control 97.0 ± 4.28 mmHg). In control animals, baroreceptor reflex sensitivity (BRS) decreased, sympathetic vasomotor activity increased, and parasympathetic activity was inhibited after CFA injection. Blood pressure elevation was evident (107.0 ± 2.75 vs. pre‐injection 97.0 ± 4.28 mmHg). Comparatively, the carrageenan‐treated rats showed a higher BRS (BrrLF 1.03 ± 0.09 vs. control 0.70 ± 0.06 ms/mmHg) and higher parasympathetic activity [0.93 ± 0.17 vs. control 0.32 ± 0.02 ln(ms2)] after CFA injection. The change in blood pressure is negligible (111.9 ± 4.05 vs. pre‐injection 110.3 ± 3.16 mmHg). Our research has shown that neonatal nociception alters future pain sensation, raises basal blood pressure level, and attenuates cardiovascular responsiveness to nociceptive stress in adult rats.
A homopolymer polymorphism in the TOMM40 gene contributes to cognitive performance in aging
Authors: Hayden Kathleen M. , McEvoy Jill M. , Linnertz Colton , Attix Deborah , Kuchibhatla Maragatha , Saunders Ann M. , Lutz Michael W. , Welsh‐Bohmer Kathleen A. , Roses Allen D. , Chiba‐Falek Ornit
Published: August 2012

Introduction

A highly polymorphic T homopolymer was recently found to be associated with late‐onset Alzheimer's disease risk and age of onset.

Objective

To explore the effects of the polymorphic polyT tract (rs10524523, referred as ‘523’) on cognitive performance in cognitively healthy elderly individuals.

Methods

One hundred eighty‐one participants were recruited from local independent‐living retirement communities. Informed consent was obtained, and participants completed demographic questionnaires, a conventional paper‐and‐pencil neuropsychological battery, and the computerized Cambridge Neuropsychological Test Automated Battery (CANTAB). Saliva samples were collected for determination of the TOMM40 ‘523’ (S, L, VL) and the apolipoprotein E (APOE) (ε2, 3, 4) genotypes. From the initial sample of 181 individuals, 127 were eligible for the association analysis. Participants were divided into three groups based on ‘523’ genotypes (S/S, S/L‐S/VL, and L/L‐L/VL‐VL/VL). Generalized linear models were used to evaluate the association between the ‘523’ genotypes and neuropsychological test performance. Analyses were adjusted for age, sex, education, depression, and APOE ε4 status. A planned subanalysis was undertaken to evaluate the association between ‘523’ genotypes and test performance in a sample restricted to APOE ε3 homozygotes.

Results

The S homozygotes performed better, although not significantly, than the S/L‐S/VL and the VL/L‐L/VL‐VL/VL genotype groups on measures associated with memory (CANTAB Paired Associates Learning, Verbal Recognition Memory free recall) and executive function (CANTAB measures of Intra‐Extra Dimensional Set Shift). Follow‐up analysis of APOE ε3 homozygotes only showed that the S/S group performed significantly better than the S/VL group on measures of episodic memory (CANTAB Paired Associates Learning and Verbal Recognition Memory free recall), attention (CANTAB Rapid Visual Information Processing latency), and executive function (Digit Symbol Substitution). The S/S group performed marginally better than the VL/VL group on Intra‐Extra Dimensional Set Shift. None of the associations remained significant after applying a Bonferroni correction for multiple testing.

Conclusions

Results suggest important APOE‐independent associations between the TOMM40 ‘523’ polymorphism and specific cognitive domains of memory and executive control that are preferentially affected in early‐stage Alzheimer's disease.
Precipitation in the Yellow River drainage basin and East Asian monsoon strength on a decadal time scale
Authors: Zhou Xin , Sun Liguang , Huang Wen , Cheng Wenhan , Jia Nan
Published: August 2012

Paleomonsoon strength is difficult to reconstruct. The strength of the East Asian monsoon and precipitation over large areas correlate well on a decadal time scale. Thus, monsoon strength can be reconstructed through proxies of sediments originating from large areas. In the present study, we investigated the characteristics of a sediment core from the Northern Yellow Sea Mud. The results showed that sedimentary characteristics are mainly controlled by discharge changes of the Yellow River. The relationships between median grain size (MZ), magnetic susceptibility (MS) and the SiO2/Al2O3 ratio of sediments and spatially averaged precipitation around the Yellow River Drainage basin reveal that changes in MZ and MS are correlated with variation in precipitation. The agreement of temporal trends in MZ, MS and the monsoon strength index confirm that spatially averaged precipitation changes in the Yellow River Drainage basin on decadal time scale are driven by the monsoon strength. These characteristics of marine sediments from the Northern Yellow Sea Mud can thus be used as proxies for monsoon strength.
KNIGHTS, JESUITS, CARNIVAL, AND THE INQUISITION IN SEVENTEENTH-CENTURY MALTA
Authors: BUTTIGIEG EMANUEL
Published: August 2012

Between 1530 and 1798, Malta, the southernmost tip of Catholic Europe, was home to the military-religious Order of St John (of Malta). This organization traced its origins to the years just before the beginning of the crusades in late eleventh-century Palestine. From Malta, the Order sought to keep up its dual mission of hospitality (hence the appellative of hospitallers) and fighting the infidel Muslim at sea. From 1592 to 1768 the Society of Jesus was present in this Catholic outpost from where it supported the mission of the Order and sought to remould hospitaller piety. The relationship between these two organizations had ramifications that spread beyond tiny Malta, both because of the issues that arose between them, as well as because of the international composition of the Order and the Society. The Carnival of 1639 proved to be a defining moment in this relationship; though generally passed over as a ‘temporary disturbance’ this article emphasizes that it was more than this by looking at the dynamics of the links between hospitallers, Jesuits, the Inquisition, and Carnival. This article is based on a wider range of sources than previous studies, which will help to bring out the nuances of the subject under investigation.
PARTY, PARLIAMENT, AND CONQUEST IN NEWLY ASCRIBED BURKE MANUSCRIPTS
Authors: BOURKE RICHARD
Published: August 2012

This article presents four manuscript essays from the mid-1750s, three of which are attributed to Edmund Burke for the first time. In doing so, the article aims to reconstruct Burke's earliest political thought during a period often described as the ‘missing years’ of his biography. These essays cover themes that would later occupy places of central importance in Burke's thinking, and so form a bridge between his early intellectual development and his subsequent political career. After presenting the grounds for ascribing these writings to Burke, the article then sketches their main lines of argument and situates them in their political context. It also briefly establishes their significance with reference to their enlightenment intellectual milieu. Covering such themes as the nature of party, the functioning of the mixed constitution, and the terms on which Ireland was subjected to the English crown, these early essays address a set of political and constitutional issues that were major areas of controversy in British politics in the second half of the eighteenth century.
HAYEK, KEYNES, AND THE ORIGINS OF NEO-LIBERALISM: A REPLY TO FARRANT AND MCPHAIL
Authors: JACKSON BEN
Published: August 2012

In reply to the comment by Andrew Farrant and Edward McPhail on Ben Jackson's article ‘At the origins of neo-liberalism’, this communication briefly examines the development of the political thought of Friedrich Hayek in the 1940s. It argues that the chronology of Hayek's critical analysis of the ‘Keynesian welfare state’ is more complex than Farrant and McPhail suggest. Farrant and McPhail underestimate the extent to which neo-liberalism in the 1940s was a body of ideas in flux, trying to come to terms with a changing political context, but not yet achieving a mature and stable ideological statement.
ISLAM AND THE EUROPEAN EMPIRES
Authors: MOTADEL DAVID
Published: August 2012

This essay surveys literature on the engagement of different European empires, including the French, British, Dutch, Russian, and German, with Islam. While the history of Islam and empire has attracted the attention of scholars for decades, most of their studies have been written primarily as contributions to the historiography of a specific empire or a distinct geographic region and rarely refer to research on other imperial powers, even though the questions and themes raised are remarkably similar. The article brings together these studies, exploring the following topics: Islam and imperial rule and, in particular, the ways in which religious institutions were accommodated and controlled in the colonial state; Islam and anti-imperial resistance; and the relationship between Islam, information, and colonial knowledge. It assesses the dominant themes in the field and points to a number of questions that remain to be studied.
Sensitivity analysis identifies high influence sites for estimates of penguin krill consumption on the Antarctic Peninsula
Authors: Lynch Heather J. , Ratcliffe Norman , Passmore Jennifer , Foster Emma , Trathan Philip N.
Published: August 2012

Krill consumption by natural predators represents a critical link between surveys and models of standing krill biomass and the design of a sustainable krill fishery for the Scotia Sea. Antarctic krill (Euphausia superba) is a significant component of diet for penguins breeding in this region and, consequently, uncertainties regarding penguin population abundances contribute to uncertainties in krill predation estimates. We use a comprehensive database of Antarctic penguin abundances to identify 14 breeding colonies that contribute most significantly to uncertainty regarding the total number of pygoscelid penguins breeding in this region. We find that a high quality survey of Zavodovski Island alone would decrease uncertainty in total population by 24.8%, whereas high quality surveys of all 14 “high-influence” locations would decrease uncertainty by almost 72%. Updated population estimates at these sites should be considered top priority for future fieldwork in the region. Our results are based on a robust quantitative method for assessing data priorities in estimating krill consumption that is easily extended to other groups of krill predators.
On Sums of Generating Sets in ℤ2n
Authors: EVEN-ZOHAR CHAIM
Published: August 2012

LetAandBbe two affinely generating sets of ℤ2n. As usual, we denote their Minkowski sum byA+B. How small canA+Bbe, given the cardinalities of A andB? We give a tight answer to this question. Our bound is attained when bothAandBare unions of cosets of a certain subgroup of ℤ2n. These cosets are arranged as Hamming balls, the smaller of which has radius 1.

By similar methods, we re-prove the Freiman–Ruzsa theorem in ℤ2n, with an optimal upper bound. Denote byF(K)the maximal spanning constant |〈A〉|/|A| over all subsetsA⊆ ℤ2nwith doubling constant |A+A|/|A| ≤K. We explicitly calculateF(K), and in particular show that 4K/4K≤F(K)⋅(1+o(1)) ≤ 4K/2K. This improves the estimateF(K)= poly(K)4K, found recently by Green and Tao [17] and by Konyagin [23].
Neonatal rat microglia derived from different brain regions have distinct activation responses
Authors: Lai Aaron Y. , Dhami Kamaldeep S. , Dibal Comfort D. , Todd Kathryn G.
Published: August 2012

The regional heterogeneity of neuronal phenotypes is a well-known phenomenon. Whether or not glia derived from different brain regions are phenotypically and functionally distinct is less clear. Here, we show that microglia, the resident immune cells of the brain, display region-specific responses for activating agents including glutamate (GLU), lipopolysaccharide (LPS) and adenosine 5′-triphosphate (ATP). Primary microglial cultures were prepared from brainstem (Brs), cortex (Ctx), hippocampus (Hip), striatum (Str) and thalamus (Thl) of 1-day-old rats and were shown to upregulate the release of nitric oxide (NO) and brain-derived neurotrophic factor (BDNF) in a region- and activator-specific manner. With respect to ATP specifically, ATP-induced changes in microglial tumor necrosis factor-α (TNF-α) release, GLU uptake and purinergic receptor expression were also regionally different. When co-cultured with hypoxia (Hyp)-injured neurons, ATP-stimulated microglia from different regions induced different levels of neurotoxicity. These region-specific responses could be altered by pre-conditioning the microglia in a different neurochemical milieu, with taurine (TAU) being one of the key molecules involved. Together, our results demonstrate that microglia display a regional heterogeneity when activated, and this heterogeneity likely arises from differences in the environment surrounding the microglia. These findings present an additional mechanism that may help to explain the regional selectiveness of various brain pathologies.
Drivers of non‐Redfield nutrient utilization in the Atlantic sector of the Southern Ocean
Authors: Giddy Isabelle S. , Swart Sebastiaan , Tagliabue Alessandro
Published: August 2012

The canonical C/N/P ratio of 106/16/1 in phytoplankton has been instrumental in our understanding of ocean biogeochemical cycles and the development of numerical models as it couples the cycling of C to nutrients. However, this ratio can show marked variability and the processes driving these trends are still uncertain. There are, in particular, two main hypotheses to explain N/P ratios that deviate from 16/1. Firstly, it is postulated that species have specific, yet distinct, ratios that are averaged out over large spatial and temporal scales. Alternatively, varying optimal growth strategies resulting from physiological adaptation to environmental conditions could drive N/P variability, which simply averages out as 16/1 under current environmental conditions. To address these hypotheses, we examine seasonal changes in the NO3− to PO43− ratio (via the geochemical tracer N*) on a section between Cape Town and Antarctica, where macronutrients are not fully depleted. Overall, we find roles for both species composition and physiology in driving the seasonal changes in N* depending on the location. Both mechanisms could act in concert and physiology was generally more important in regions undergoing large changes in phytoplankton biomass. Better understanding the driving mechanisms behind changes in the Southern Ocean N/P ratio is important as its signal is exported to low latitudes, having major impacts on global biogeochemical cycles.
Roles of upper‐level processes in tropical cyclogenesis
Authors: Zhang Da‐Lin , Zhu Lin
Published: August 2012

Previous studies have focused mostly on the impact of lower‐level vorticity growth and other lower‐level processes on tropical cyclogenesis (TCG). In this study, the importance of upper‐level processes in TCG is studied in terms of the minimum sea‐level pressure (MSLP) changes with two cases exhibiting different warm‐core heights and vorticity structures due to their developments in the respective weak‐ and strong‐sheared environment. Results show that the upper‐level warming could account for more than 75% the MSLP changes in both cases. Widespread deep convection during the early TCG stage tends to warm the upper troposphere and induce meso‐α‐scale surface pressure falls. Upper‐level flow and vertical wind shear (VWS) will suppress the formation of a warm core due to the presence of weak inertial stability, whereas the development of upper‐level divergent outflows favors its formation. Results also show that TCG is triggered when the upper‐level warming amplitude and depth increase as a result of weak or significantly reduced ventilation and VWS aloft. Results suggest that both the upper‐ and low‐level processes be considered in the understanding and prediction of TCG.
Aerosol and gas re‐distribution by shallow cumulus clouds: An investigation using airborne measurements
Authors: Wonaschuetz Anna , Sorooshian Armin , Ervens Barbara , Chuang Patrick Y. , Feingold Graham , Murphy Shane M. , de Gouw Joost , Warneke Carsten , Jonsson Haflidi H.
Published: August 2012

Aircraft measurements during the 2006 Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) are used to examine the influence of shallow cumulus clouds on vertical profiles of aerosol chemical composition, size distributions, and secondary aerosol precursor gases. The data show signatures of convective transport of particles, gases and moisture from near the surface to higher altitudes, and of aqueous‐phase production of aerosol mass (sulfate and organics) in cloud droplets and aerosol water. In cloudy conditions, the average aerosol volume concentration at an altitude of 2850 m, above typical cloud top levels, was found to be 34% of that at 450 m; for clear conditions, the same ratio was 13%. Both organic and sulfate mass fractions were on average constant with altitude (around 50%); however, the ratio of oxalate to organic mass increased with altitude (from 1% at 450 m to almost 9% at 3450 m), indicative of the influence of in‐cloud production on the vertical abundance and characteristics of secondary organic aerosol (SOA) mass. A new metric termed “residual cloud fraction” is introduced as a way of quantifying the “cloud processing history” of an air parcel. Results of a parcel model simulating aqueous phase production of sulfate and organics reproduce observed trends and point at a potentially important role of SOA production, especially oligomers, in deliquesced aerosols. The observations emphasize the importance of shallow cumulus clouds in altering the vertical distribution of aerosol properties that influence both their direct and indirect effect on climate.
Functional comparison of Deinococcus radiodurans Dps proteins suggests distinct in vivo roles
Authors: Reon Brian J. , Nguyen Khoa H. , Bhattacharyya Gargi , Grove Anne
Published: August 2012

Deinococcus radiodurans exhibits extreme resistance to DNA damage and is one of only few bacteria that encode two Dps (DNA protection during starvation) proteins. Dps-1 was shown previously to bind DNA with high affinity and to localize to the D. radiodurans nucleoid. A unique feature of Dps-2 is its predicted signal peptide. In the present paper, we report that Dps-2 assembly into a dodecamer requires the C-terminal extension and, whereas Dps-2 binds DNA with low affinity, it protects against degradation by reactive oxygen species. Consistent with a role for Dps-2 in oxidative stress responses, the Dps-2 promoter is up-regulated by oxidative stress, whereas the Dps-1 promoter is not. Although DAPI (4′,6-diamidino-2-phenylindole) staining of Escherichia coli nucleoids shows that Dps-1 can compact genomic DNA, such nucleoid condensation is absent from cells expressing Dps-2. A fusion of EGFP (enhanced green fluorescent protein) to the Dps-2 signal peptide results in green fluorescence at the perimeter of D. radiodurans cells. The differential response of the Dps-1 and Dps-2 promoters to oxidative stress, the distinct cellular localization of the proteins and the differential ability of Dps-1 and Dps-2 to attenuate hydroxyl radical production suggest distinct functional roles; whereas Dps-1 may function in DNA metabolism, Dps-2 may protect against exogenously derived reactive oxygen species.
Soft x-ray images of the laser entrance hole of ignition hohlraums
Authors: Schneider M. B. , Meezan N. B. , Alvarez S. S. , Alameda J. , Baker S. , Bell P. M. , Bradley D. K. , Callahan D. A. , Celeste J. R. , Dewald E. L. , Dixit S. N. , Döppner T. , Eder D. C. , Edwards M. J. , Fernandez-Perea M. , Gullikson E. , Haugh M. J. , Hau-Riege S. , Hsing W. , Izumi N. , Jones O. S. , Kalantar D. H. , Kilkenny J. D. , Kline J. L. , Kyrala G. A. , Landen O. L. , London R. A. , MacGowan B. J. , MacKinnon A. J. , Mccarville T. J. , Milovich J. L. , Mirkarimi P. , Moody J. D. , Moore A. S. , Myers M. D. , Palma E. A. , Palmer N. , Pivovaroff M. J. , Ralph J. E. , Robinson J. , Soufli R. , Suter L. J. , Teruya A. T. , Thomas C. A. , Town R. P. , Vernon S. P. , Widmann K. , Young B. K.
Published: August 2012

Hohlraums are employed at the national ignition facility to convert laser energy into a thermal x-radiation drive, which implodes a fusion capsule, thus compressing the fuel. The x-radiation drive is measured with a low spectral resolution, time-resolved x-ray spectrometer, which views the region around the hohlraum's laser entrance hole. This measurement has no spatial resolution. To convert this to the drive inside the hohlraum, the size of the hohlraum's opening (“clear aperture”) and fraction of the measured x-radiation, which comes from this opening, must be known. The size of the clear aperture is measured with the time integrated static x-ray imager (SXI). A soft x-ray imaging channel has been added to the SXI to measure the fraction of x-radiation emitted from inside the clear aperture. A multilayer mirror plus filter selects an x-ray band centered at 870 eV, near the peak of the x-ray spectrum of a 300 eV blackbody. Results from this channel and corrections to the x-radiation drive are discussed.
The role of excess minority carriers in light induced degradation examined by photoluminescence imaging
Authors: Nærland Tine Uberg , Angelskår Hallvard , Kirkengen Martin , Søndenå Rune , Marstein Erik Stensrud
Published: August 2012

A new approach to investigate light induced degradation (LID) effects in boron-doped silicon has been developed. By studying spatial variations in LID resulting from localized carrier excitation (spot-LID), it is verified that the generation of the boron-oxygen complexes responsible for the degradation is directly related to the presence of excess minority carriers. Through the examination of the diffused minority carrier density distribution (during light exposure), from an exposed into an unexposed wafer area compared to the observed defect generation, we are able to monitor the generation of excess carrier induced defects over a range of carrier concentrations. The results show that very low concentrations of minority excess carrier densities are sufficient to generate the defects. For the investigated material carrier concentrations down to 1.7 ± 0.2 × 109 cm−3 are observed to cause lifetime degradation.
The atomic structure of protons and hydrides in Sm1.92Ca0.08Sn2O7−δ pyrochlore from DFT calculations and FTIR spectroscopy
Authors: Bork N. , Eurenius K. E. J. , Rossmeisl J. , Knee C. S. , Vegge T.
Published: August 2012

A combined density functional theory and Fourier transform infrared spectroscopy study of the structure and specific site preference of protons and hydrides in the pyrochlore Sm1.92Ca0.08Sn2O7−δ is presented. Two protonic sites of particular high stability are identified, both located on O(1) oxygen atoms closely associated with a Ca dopant. Further, the unexpected presence of HO hydride defects in undoped, oxygen deficient Sm2Sn2O7 is reported. Finally, the stretching frequencies and relative intensities for these and other sites are calculated. The main features of the Fourier transform infrared spectra are hereby resolved.
Photodissociation of van der Waals clusters of isoprene with oxygen, C5H8−O2, in the wavelength range 213–277 nm
Authors: Vidma Konstantin V. , Frederix Pim W. J. M. , Parker David H. , Baklanov Alexey V.
Published: August 2012

The speed and angular distribution of O atoms arising from the photofragmentation of C5H8−O2, the isoprene-oxygen van der Waals complex, in the wavelength region of 213–277 nm has been studied with the use of a two-color dissociation-probe method and the velocity map imaging technique. Dramatic enhancement in the O atoms photo-generation cross section in comparison with the photodissociation of individual O2 molecules has been observed. Velocity map images of these “enhanced” O atoms consisted of five channels, different in their kinetic energy, angular distribution, and wavelength dependence. Three channels are deduced to be due to the one-quantum excitation of the C5H8−O2 complex into the perturbed Herzberg III state (3Δu) of O2. This excitation results in the prompt dissociation of the complex giving rise to products C5H8+O+O when the energy of exciting quantum is higher than the complex photodissociation threshold, which is found to be 41740 ± 200 cm−1 (239.6±1.2 nm). This last threshold corresponds to the photodissociation giving rise to an unexcited isoprene molecule. The second channel, with threshold shifted to the blue by 1480 ± 280 cm−1, corresponds to dissociation with formation of rovibrationally excited isoprene. A third channel was observed at wavelengths up to 243 nm with excitation below the upper photodissociation threshold. This channel is attributed to dissociation with the formation of a bound O atom C5H8−O2 + hv → C5H8−O2(3Δu) → C5H8O + O and/or to dissociation of O2 with borrowing of the lacking energy from incompletely cooled complex internal degrees of freedom C5H8*−O2 + hv → C5H8*−O2(3Δu) → C5H8 + O + O. The kinetic energy of the O atoms arising in two other observed channels corresponds to O atoms produced by photodissociation of molecular oxygen in the excited a 1Δg and ${\rm b\,}^1 \Sigma _g^ +$b1Σg+ singlet states as the precursors. This indicates the formation of singlet oxygen O2(a 1Δg) and O2(${\rm b\, }^1 \Sigma _g^ +$b1Σg+) after excitation of the C5H8−O2 complex. Cooperative excitation of the complex with a simultaneous change of the spin of both partners 1X−3O2 + hν → 3X−1O2 → 3X + 1O2 is suggested as a source of singlet oxygen O2(a 1Δg) and O2(${\rm b \,}^1 \Sigma _g^ +$b1Σg+). This cooperative excitation is in agreement with little or no vibrational excitation of O2(a 1Δg), produced from the C5H8−O2 complex as studied in the current paper as well as from the C3H6−O2 and CH3I−O2 complexes reported in our previous paper [Baklanov et al., J. Chem. Phys. 126, 124316 (2007)]. The formation of O2(a 1Δg) from C5H8−O2 was observed at λpump = 213–277 nm with the yield going down towards the long wavelength edge of this interval. This spectral profile is interpreted as the red-side wing of the band of a cooperative transition 1X−3O2 + hν → 3X(T2)−1O2(a 1Δg) in the C5H8−O2 complex.
Ultrafast time resolved x-ray diffraction, extended x-ray absorption fine structure and x-ray absorption near edge structure
Authors: Oguz Er Ali , Chen Jie , Rentzepis Peter M.
Published: August 2012

Ultrafast time resolved x-ray absorption and x-ray diffraction have made it possible to measure, in real time, transient phenomena structures and processes induced by optical femtosecond pulses. To illustrate the power of these experimental methods, we present several representative examples from the literature. (I) Time resolved measurements of photon/electron coupling, electron/phonon interaction, pressure wave formation, melting and recrystallization by means of time resolved x-ray diffraction. (II) Ultrafast x-ray absorption, EXAFS, for the direct measurement of the structures and their kinetics, evolved during electron transfer within molecules in liquid phase. (III) XANES experiments that measure directly pathway for the population of high spin states and the study of the operating mechanism of dye activated TiO2 solar cell devices. The construction and use of novel polycapillary x-ray lenses that focus and collimate hard x-rays efficiently are described.
Note: Series and parallel tunable resonators based on a nematic liquid crystal cell as variable capacitance
Authors: Torres Juan C. , Marcos Carlos , Sánchez-Pena José M. , Pérez Isabel , Urruchi Virginia
Published: August 2012

In this work, tunable series and parallel resonators based on a nematic liquid crystal cell as variable capacitance are proposed and characterized. Tunable resonance frequencies in the range of kHz have been obtained for the combination of the inductance and the liquid crystal cell (capacitance) used in the proposed circuits. Tuning range in frequency obtained is around an octave.