bluuebunny/crossref_metadata_2025 huggingface dataset:
Molybdenum‐catalyzed epoxidations of oct‐1‐ene and cyclohexene with organic hydroperoxides: Steric effects of the alkyl substituents of the hydroperoxide on the reaction rate
Authors: Lempers H.E.B. , van Crey M.J. , Sheldon R.A.
Published: September 2010

A kinetic study of the epoxidation of oct‐1‐ene and cyclohexene with alkyl hydroperoxides is reported. The alkyl hydroperoxides were obtained in a moderate to high purity from the corresponding alcohols by acid‐catalyzed exchange with hydrogen peroxide. The reaction rates in pseudo first‐order experiments of these olefins with various alkyl hydroperoxides strongly depend on the structure of the alkyl group of the alkyl hydroperoxide. When one of the methyl groups in tert‐butyl hydroperoxide (TBHP, 4a) is substituted by an alkyl group, R, the reaction rate decreases in the order Et > Pr > Bu >1 BuCH2 > tBu. Substitution of two methyl groups of TBHP as in 1‐ethyl‐1‐methylpropyl hydroperoxide (5a) and 1‐ethyl‐1‐methylbutyl hydroperoxide (5b) showed a further decrease in reaction rate of epoxidation. When all three methyl groups are substituted by, for example, three ethyl groups as in 1,1‐diethylpropyl hydroperoxide (6a) a decrease of approximately 99% in reaction rate is observed. Introduction of a ring system in the hydroperoxide such as in cyclohexyl hydroperoxide (3), 1‐methyl‐cyclohexyl hydroperoxide (2) and pinane hydroperoxide (1) also showed a dramatic decrease in reaction rate of epoxidation.

An investigation of relative rates of epoxidation in competition experiments of cyclohexene and hex‐1‐ene with 1‐tert‐butylcyclohexene with different alkyl hydroperoxides also showed them to depend on the structure of the alkyl group of the alkyl hydroperoxide.

These results are rationalized on the basis of a mechanism involving nucleophilic attack of the olefin on an alkylperoxomolybdenum(VI) intermediate. Bulky substituents at the α‐position in the alkyl hydroperoxide can seriously impede the approach of the olefin to the O‐O bond.
A review on scale and siting of wind farms in China
Authors: Deng Yuanchang , Yu Zhi , Liu Sha
Published: September 2010

Using a wind power information system, which is based on the geographic information system (GIS), this paper presents a statistical analysis of built and approved wind farms to the end of 2008. The average capacity of wind turbine generators (WTGs) and the scale of wind farms are investigated. The geographical distribution of wind farms and the main factors affecting wind farm siting are analysed. The results show: (i) The average capacity of WTGs is increasing; MW scale WTGs have become the mainstream product in the China market. (ii) Because of the national wind project approval policy, most of the wind farms have installed capacities of just under 50 MW. (iii) When siting a wind farm, wind resource is still the predominant factor being considered, while grid connection is still the main constraint in this stage. (iv) Concerning land use, among the wind farms built by 2008, 40% use grasslands, 31% use agricultural land, 17% use desert or bare lands, while 12% use farmlands. (v) Statistics show 88.6% of the built wind farms have elevation change of less than 300 m, and 90% of the built wind farms have GIS slopes of less than 10°. (vi) The geographical distribution of wind farms reveals a highly concentrated deployment tendency, 58.7% of all the newly built wind farms in 2008 are within 10 km of existing wind farms. Copyright © 2010 John Wiley & Sons, Ltd.
Viral tRNAs and tRNA‐like structures
Authors: Dreher Theo W.
Published: September 2010

Viruses commonly exploit or modify some aspect of tRNA biology. Large DNA viruses, especially bacteriophages, phycodnaviruses, and mimiviruses, produce their own tRNAs, apparently to adjust translational capacity during infection. Retroviruses recruit specific host tRNAs for use in priming the reverse transcription of their genome. Certain positive‐strand RNA plant viral genomes possess 3′‐tRNA‐like structures (TLSs) that are built quite differently from authentic tRNAs, and yet efficiently recapitulate several properties of tRNAs. The structures and roles of these TLSs are discussed, emphasizing the variety in both structure and function. © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems

RNA Interactions with Proteins and Other Molecules > Protein–RNA Interactions: Functional Implications

Translation > Translation Regulation

RNA Processing > tRNA Processing
Quantitative analysis of phosphorylation‐based protein signaling networks in the immune system by mass spectrometry
Authors: Nita‐Lazar Aleksandra
Published: September 2010

Dynamic modification of cell proteins with phosphate is one of the key regulators of the cellular response to external stimuli. Phosphorylation‐based signaling networks mediate cell proliferation, differentiation, and migration, and their dysregulation is the basis of multiple diseases. However, the transient nature of the regulatory protein phosphorylation and low site occupancy mean that only a fraction of the protein is phosphorylated at a given time, and it is a challenge to measure the degree and dynamics of phosphorylation using traditional biochemical means. Technological advances in the field of mass spectrometry (MS) made it possible to generate large sets of phosphoproteomics data, probing the phosphoproteome with great depth, sensitivity, and accuracy. Therefore, quantitative phosphoproteomics emerged as one of the essential components of the systems biology approach for profiling of complex biological networks. Nowadays, the challenge lies in validation of the information and in its integration into the comprehensive models of cell decision processes. This article reviews the role of phosphoproteomics in systems biology, the MS‐based approach, and technical details of the methods. Recent examples of quantitative measurements and methodologies as well as applications to the studies of the immune system and infectious diseases are presented and discussed. WIREs Syst Biol Med 2011 3 368–376 DOI: 10.1002/wsbm.123

This article is categorized under:

Laboratory Methods and Technologies > Proteomics Methods
Zur Methodik der Absorptions‐ und Reflexionsspektroskopie extrem sauerstoffempfindlicher Verbindungen
Authors: König E. , Schläfer H. L. , Herzog S.
Published: September 2010

Die Möglichkeiten smr Aufnahme von Absorptions‐ und Reflexionsspektren extrem sauerstoffempfindlicher Verbindungen werden beschrieben. Außerdem werden die dazu notwendigen apparativen Hilfsmittel sowie geeignete Verfahren zur Lösungsmittelreinigung angegeben.
Kalorimetrie kristallin‐flüssiger Substanzen Kalorische Daten und molekulare Wechselwirkung in der Reihe der Dialkoxyazoxybenzole
Authors: Arnold H.
Published: September 2010

Im Hinblick auf die Besonderheiten der molekularen Ordnung in kristallinen Flüssigkeiten wird für die homologe Reihe der 4,4′‐Di‐n‐alkoxy‐azoxybenzole eine vergleichende Betrachtung der Molwärmen im kristallinfesten, smektischen, nematischen und isotrop‐flüssigen Zustand sowie der latenten Wärmen der Phasenübergänge vorgenommen. Eine Gegenüberstellung mit den Aussagen der molekularstatistischen Theorie vonMaierundSaupeüber die nematischen Phasen ergibt, daß der Anstieg der Molwärmen unterhalb der Klärpunktstemperatur als Auswirkung eines verstärkten Abbaus der kristallin‐flüssigen Ordnung gedeutet werden kann. Für die Umwandlungswärme am Klärpunkt zeigt sich beim Dimethoxyazoxybenzol eine größenordnungsmäßige Übereinstimmung, während der Gang der Werte beim Fortschreiten in der homologen Reihe durch die Theorie nicht befriedigend wiedergegeben wird.
Synthesen mit α‐Halogenäthern
Authors: Groβ Hans , Höft Eugen , Rieche A.
Published: September 2010

α‐Halogenäther sind seit langem in verschiedenen Arbeitskreisen untersucht worden. Dabei wurde gefunden, daß diese Verbindungsklasse auf Grund ihrer besonderen Reaktionsfähigkeit als präparative Hilfsmittel bzw. als Zwischenprodukte für eine ganze Reihe verschiedener Synthesen eingesetzt werden können. Die Chemie der α‐Halogenäther wurde mehrfach unter verschiedenen Gesichtspunkten zusammengefaßt, so z. B. von Summers [1], Baganz [2], Issaguljanz und Below [3] sowie von Groβ und Höft [4]. In neuerer Zeit wurden von mehreren Seiten interessante neue Anwendungsmöglichkeiten gefunden, so daß eine Zusammenfassung der Reaktionsmöglichkeit der α‐Halogenäther sowie in einigen Fällen auch der ganz analog reagierenden α‐Halogenester, α‐Halogencarbonate und α‐Halogenthioäther gerechtfertigt erscheint. In dem vorliegenden Überblick wurde besonderer Wert auf solche Reaktionen gelegt, die im organisch‐präparativen Maßstab von Interesse sind. Ältere Arbeiten konnten hier z. T. nicht berücksichtigt werden. Hierzu sei auf die nahezu vollständige Literaturübersicht der Arbeiten über α‐Halogenäther von Summers verwiesen (Literatur bis Anfang 1954). α‐Fluoräther zeigen allgemein gegenüber den anderen Halogenäthern ein abweichendes Reaktionsverhalten. Sie werden deshalb in dieser Zusammenfassung nicht berücksichtigt.
Über Substituenten‐Konstanten
Authors: Schott Günther
Published: September 2010

Es wird ein Überblick über die zahlreichen in der Literatur enthaltenen Varianten von σ‐Konstanten gegeben. Die verschiedenen σ‐Konstanten werden hinsichtlich ihrer Anwendungsbereiche verglichen und ihre gegenseitigen Beziehungen werden untersucht. Mit der vorliegenden Übersicht wird eine nachfolgende Veröffentlichung [1] vorbereitet, in der die Anwendbarkeit von σ‐Konstanten zur Beurteilung der Reaktionsfähigkeit von Organo‐Silicium‐Verbindungen behandelt wird.
Cetane Number Prediction of Biodiesel from the Composition of the Fatty Acid Methyl Esters
Authors: Tong Dongmei , Hu Changwei , Jiang Kanghua , Li Yuesong
Published: September 2010

In the present work, the measured cetane numbers (CN) of pure fatty acid methyl esters (FAME), as well as the FAME compositions and the reported CN of 59 kinds of biodiesels collected from literature were used to develop a simple model involving as more FAME component as possible for predicting CN of biodiesel from its FAME composition. Two different regression equations correlating the CN of pure FAME with the carbon number of fatty acid chain were obtained by regression analysis, which shows that the dependence of the CN on the carbon number varies with the unsaturated degree of fatty acid chain. The 59 biodiesels were divided into two categories and used, respectively to develop and test a multiple linear regression model (MLRM) correlating the CN of biodiesel with its FAME composition. A simple and convenient regression equation with a high accuracy and a good reproducibility (average absolute error of 0.49 CN for testing set and 1.52 CN for all data) were developed, showing excellent correlation (R2: 0.9904 for testing set). The model developed in the present work can be used conveniently to give a satisfactory predicted CN of biodiesel from the FAME composition.
Preliminary evaluation of implementing the Ponseti method for correction of clubfoot in Vietnam
Authors: Evans Angela Margaret
Published: September 2010

Purpose

To evaluate the short-term results of the non-surgical Ponseti method training programs run in Ho Chinh Minh City, Vietnam.

Methods

A questionnaire was developed and distributed to the 57 trainees who had completed one of the 3-day training courses.

Results

Of the 57 questionnaires distributed, 36 (63%) were completed and returned for evaluation. Most responders were continuing to use the Ponseti method for management of clubfoot. On average, each trainee had treated 16 babies with clubfoot, most of whom were less than 12 months of age, within 2 years of the initial training course and were achieving good clinical correction. The major problems identified were the inability to perform an Achilles tenotomy, lack of availability of the foot abduction splint, and parent compliance. The course materials were being used for reference and for dissemination of the Ponseti method to other clinical peers.

Conclusions

Evaluation of the Ponseti method training program for management of clubfoot in Vietnam revealed continued use of the technique at 12–24 months post-training. A longer term and more objective assessment of the babies/children treated and of the associated gait function and foot comfort would be beneficial.
DETERMINANTS OF INDUCED ABORTION: AN ANALYSIS OF INDIVIDUAL, HOUSEHOLD AND CONTEXTUAL FACTORS IN RAJASTHAN, INDIA
Authors: ELUL BATYA
Published: September 2010

In the developing world, little is known about the risk and precipitating factors for abortion, due to a dearth of community-based surveys. Most analyses of determinants of induced abortion consider only a small set of household and individual socio-demographic factors and treat abortion as an isolated outcome, which ignores its relationship with prior reproductive health behaviours and experiences. In this paper, data from a cross-sectional survey of abortion knowledge, attitudes and practices among 2571 currently married women of reproductive age in Rajasthan, India, were used to examine contextual-, household- and individual-level determinants of abortion. Bivariate probit models, which jointly determine the probability of pregnancy and the conditional probability of abortion, were used to reflect the probability of abortion as a result of interrelated and sequential events. Increased socioeconomic status and life-cycle factors were associated with both the probability of pregnancy and with the conditional likelihood of abortion. Women who reported personal networks were also more likely to terminate pregnancies, particularly if their network members purportedly had abortion experience. Community knowledge of sex-selective abortion also exerted a significant positive effect on the propensity to terminate a pregnancy. For rural women only, community beliefs regarding spousal consent requirements pre-abortion were also significantly associated with abortion.
Heterogeneity and Volatility Puzzles in International Finance
Authors: Li Tao , Muzere Mark L.
Published: September 2010

We develop an equilibrium model in a 2-country, 2-good, pure exchange economy in which investors with logarithmic utility functions have heterogeneous beliefs about exogenously given output or endowment processes. We obtain closed-form representations of real exchange rates and of stock prices. We show that heterogeneous beliefs together with heterogeneous preferences make the volatility of real exchange rates and of stocks exhibit some properties that have been well documented in the empirical literature. These properties include the high volatility of both real exchange rates and stocks compared with that of economic fundamentals, the high correlation of stocks during periods of volatile markets. The model can also generate the clustering of the volatility of foreign exchange rates and stocks if the differences of beliefs are clustering.
Validation of self-reported hearing loss using television volume
Authors: Ranganathan B , Counter P , Johnson I
Published: September 2010

Objective:

To assess the diagnostic utility of using television volume as a marker for hearing loss.

Study design:

Prospective study using a self-administered questionnaire.

Setting:

ENT and audiology out-patient departments in the north of England.

Participants:

One hundred and seventeen patients with a history of hearing loss, undergoing pure tone audiometry for the first time.

Main outcome measures:

sensitivity, specificity, diagnostic accuracy, and positive and negative predictive value of television volume as a marker of hearing loss.

Results:

The data indicated that if the patient (or their partner or parent) reported viewing television with an increased volume, then there was a 68 per cent chance of the patient having a hearing loss of 25 dB or more. Patients reporting increased television volume had a mean hearing loss of 35 dB. Increased television volume had a sensitivity of 81 per cent and a specificity of 52 per cent as a predictor of hearing loss. Patients who increased their television volume to watch news programmes had an average hearing loss of 41 dB; increased television volume for news programmes had a sensitivity of 75 per cent and a specificity of 71 per cent as a predictor of hearing loss.

Conclusions:

Television volume is a useful marker of hearing loss in situations where audiometry is unavailable, for instance in a primary care setting. However, it is not a very specific test.
Easily, At a Glance: Aristotle's Political Optics
Authors: Janssens David
Published: September 2010

In book VII of thePolitics, Aristotle requires that the best regime beeusunoptos, “easily taken in at a glance.” Throughout the history of political thought, the attendant ideal of thepolisas a compact and surveyable society was particularly influential. However, closer scrutiny of the way in which Aristotle useseusunoptossuggests that it designates aproblemrather than a solution, to wit, the problems of defining political unity and of attuning the individual and the common good. Exploring the different contexts in whicheusunoptosoccurs in Aristotle's works, this paper argues that it has political, rhetorical, and poetical meanings that cannot be entirely distinguished from each other. As such, the notion is shown to be germane to the general design of book VII, which constructs the best regime in order to bring to light the limits of politics.
Liberty, Equality, and the Boundaries of Ownership: Thomas Paine's Theory of Property Rights
Authors: Lamb Robert
Published: September 2010

Thomas Paine is customarily regarded as a pamphleteer, rhetorician, and polemicist rather than a significant political theorist. This article takes the philosophical content of Paine's thought seriously and argues that his account of property rights constitutes a distinct contribution to theoretical debates on the subject. Drawing on Paine'sAgrarian Justiceand other writings, this article shows that his theory of property defends a libertarian concern with private ownership that contains within its logic an egalitarian commitment to the redistribution of resources. Paine's justification of property is distinct from that of various other important figures in the history of ideas (including Grotius, Pufendorf, and Locke) and represents his simultaneous commitment to foundational liberal values of individual freedom and moral equality.
Architecture optimization of 4PUS+1PS parallel manipulator
Authors: Abbasnejad G. , Daniali H. M. , Fathi A.
Published: September 2010

The main goal of this paper is the design of 4PUS+1PS parallel manipulator, using an optimization problem that takes into accounts the characteristics of the workspace and dexterity. The optimization problem is formulated considering constraints on actuated and passive joint limits. A comparison between quantum particle swarm Optimization (QPSO) and PSO is developed. Two numerical examples are presented, which reveal the advantages of QPSO to PSO. Moreover, it is shown that by introducing the dexterity index as a quality measure throughout the workspace, the parallel manipulator is improved at the cost of a minor reduction in its workspace.
SPECIFICATION TESTING IN MODELS WITH MANY INSTRUMENTS
Authors: Anatolyev Stanislav , Gospodinov Nikolay
Published: September 2010

This paper studies the asymptotic validity of the Anderson–Rubin (AR) test and theJtest for overidentifying restrictions in linear models with many instruments. When the number of instruments increases at the same rate as the sample size, we establish that the conventionalARandJtests are asymptotically incorrect. Some versions of these tests, which are developed for situations with moderately many instruments, are also shown to be asymptotically invalid in this framework. We propose modifications of theARandJtests that deliver asymptotically correct sizes. Importantly, the corrected tests are robust to the numerosity of the moment conditions in the sense that they are valid for both few and many instruments. The simulation results illustrate the excellent properties of the proposed tests.
Natural discourse reference generation reduces cognitive load in spoken systems
Authors: CAMPANA E. , TANENHAUS M. K. , ALLEN J. F. , REMINGTON R.
Published: September 2010

The generation of referring expressions is a central topic in computational linguistics. Natural referring expressions – both definite references like ‘the baseball cap’ and pronouns like ‘it’ – are dependent on discourse context. We examine the practical implications of context-dependent referring expression generation for the design ofspoken systems. Currently, not all spoken systems have the goal of generating natural referring expressions. Many researchers believe that the context-dependency of natural referring expressions actually makes systemslessusable. Using the dual-task paradigm, we demonstrate that generating natural referring expressions that are dependent on discourse context reduces cognitive load. Somewhat surprisingly, we also demonstrate that practice does not improve cognitive load in systems that generate consistent (context-independent) referring expressions. We discuss practical implications for spoken systems as well as other areas of referring expression generation.
EXPRESSIBLE SEMANTICS FOR EXPRESSIBLE COUNTERFACTUALS
Authors: CHEMLA EMMANUEL
Published: September 2010

Lewis (1981) showed the equivalence between two dominant semantic frameworks for counterfactuals: ordering semantics, which relies on orders between possible worlds, and premise semantics, which relies on sets of propositions (so-called ordering sources). I define a natural, restricted version of premise semantics, expressible premise semantics, which is based on ordering sources containing only expressible propositions. First, I extend Lewis’ (1981) equivalence result to expressible premise semantics and some corresponding expressible version of ordering semantics. Second, I show that expressible semantics are strictly less powerful than their nonexpressible counterparts, even when attention is restricted to the truth values of expressible counterfactuals. Assuming that the expressibility constraint is natural for premise semantics, this result breaks the equivalence between ordering semantics and (expressible) premise semantics. Finally, I show that these results cast doubt on various desirable conjectures, and in particular on a particular defense of the so-called limit assumption.
Kinetics of parametric instabilities of Alfvén waves: Evolution of ion distribution functions
Authors: Matteini Lorenzo , Landi Simone , Velli Marco , Hellinger Petr
Published: September 2010

Using numerical simulations in a hybrid regime, we studied the evolution of large‐amplitude Alfvén waves subject to modulational and decay instabilities, including the effects of ion kinetics. We considered both a monochromatic and incoherent spectrum of waves, different wave polarizations and amplitudes, and different plasma regimes, ranging from β < 1 to β > 1. We found in all cases that ion dynamics affects the instability evolution and saturation; as a feedback, wave‐particle interactions provide a nonlinear trapping of resonant particles that importantly change the properties of the ion velocity distribution functions. In particular, we observed a proton acceleration along the magnetic field and in some cases the formation of a parallel velocity beam traveling faster than the rest of the distribution. For the range of parameters used in our simulations, the fundamental ingredient in generating an ion beam is observed to be the parallel electric field carried by the density fluctuations driven by the ion‐acoustic modes generated by the parametric instabilities.
Anisotropy, repeating earthquakes, and seismicity associated with the 2008 eruption of Okmok volcano, Alaska
Authors: Johnson Jessica H. , Prejean Stephanie , Savage Martha K. , Townend John
Published: September 2010

We use shear wave splitting (SWS) analysis and double‐difference relocation to examine temporal variations in seismic properties prior to and accompanying magmatic activity associated with the 2008 eruption of Okmok volcano, Alaska. Using bispectrum cross‐correlation, a multiplet of 25 earthquakes is identified spanning five years leading up to the eruption, each event having first motions compatible with a normal fault striking NE–SW. Cross‐correlation differential times are used to relocate earthquakes occurring between January 2003 and February 2009. The bulk of the seismicity prior to the onset of the eruption on 12 July 2008 occurred southwest of the caldera beneath a geothermal field. Earthquakes associated with the onset of the eruption occurred beneath the northern portion of the caldera and started as deep as 13 km. Subsequent earthquakes occurred predominantly at 3 km depth, coinciding with the depth at which the magma body has been modeled using geodetic data. Automated SWS analysis of the Okmok catalog reveals radial polarization outside the caldera and a northwest‐southeast polarization within. We interpret these polarizations in terms of a magma reservoir near the center of the caldera, which we model with a Mogi point source. SWS analysis using the same input processing parameters for each event in the multiplet reveals no temporal changes in anisotropy over the duration of the multiplet, suggesting either a short‐term or small increase in stress just before the eruption that was not detected by GPS, or eruption triggering by a mechanism other than a change of stress in the system.
Eastern Pacific oxygen minimum zones: Supply paths and multidecadal changes
Authors: Stramma Lothar , Johnson Gregory C. , Firing Eric , Schmidtko Sunke
Published: September 2010

The supply of oxygen‐rich water to the oxygen minimum zones (OMZs) of the eastern North and South Pacific via zonal tropical currents is investigated using shipboard acoustic Doppler current profiler and hydrographic section data. Near the equator, the Equatorial Undercurrent (EUC), Northern and Southern Subsurface Countercurrents (SCCs), and the Northern and Southern Intermediate Countercurrents (ICCs) all carry water that is oxygen richer than adjacent westward flows, thereby providing a net oxygen supply to the eastern Pacific OMZs. The synoptic velocity‐weighted oxygen concentration difference between eastward and westward flows is typically 10–50 μmol kg−1. Subthermocline zonal oxygen fluxes reflect decreasing oxygen concentrations of the EUC, the SCCs, and the ICCs as they flow eastward. Approximately 30 year time series in well‐sampled regions of the equatorial Pacific show oxygen content decreasing as rapidly as −0.55 μmol kg−1 yr−1 in the major oxygen supply paths of the OMZs for a 200–700 m layer and similar trends for a density layer spanning roughly these depths. This finding is in gross agreement with climate models, which generally predict expanding OMZs.
Shear wave velocity imaging of the Avignonet landslide (France) using ambient noise cross correlation
Authors: Renalier F. , Jongmans D. , Campillo M. , Bard P.‐Y.
Published: September 2010

The Avignonet landslide affects a 2 by 2 km area covered by clayey deposits. This paper presents the use of the seismic ambient noise cross‐correlation technique to retrieve a 3‐D model of the shear wave velocity of the area. Seismic ambient noise was recorded during 15 days at 13 stations located on the landslide. Cross correlations computed between the vertical components of all station pairs allow the retrieval of the Rayleigh wave Green's functions and the estimation of their group velocity dispersion curves in the 1.7–5 Hz frequency range. At frequencies lower than 1.5 Hz, the anisotropy of the wavefield strongly influences the apparent Rayleigh wave velocities. Moreover, the analysis of the convergence of the cross correlations shows that at frequencies higher than 5 Hz, the recording time length was not sufficient for the cross correlation to be stable. These 1.7–5 Hz passive group dispersion curves are complementary to the ones computed from shot signals in the 3–7 Hz frequency range. A tomographic inversion of the resulting 1.7–7 Hz Rayleigh wave group dispersion curves provides local group dispersion curves at each cell of the tomographic grid. These are inverted with a neighborhood algorithm to retrieve the 3‐D model of the landslide. Despite the complex wave propagation in the eastern part of the landslide and the sparse ray coverage, estimated velocities and first‐order features are in good agreement with previous investigations.
Relative contributions of soil, foliar, and woody tissue respiration to total ecosystem respiration in four pine forests of different ages
Authors: Khomik Myroslava , Arain M. Altaf , Brodeur Jason J. , Peichl Matthias , Restrepo‐Coupé Natalia , McLaren Joshua D.
Published: September 2010

Carbon dioxide (CO2) emissions from soil, foliage, and live woody tissue were measured throughout the year in afforested, white pine (Pinus strobus L.) stands (67, 32, 17, and 4 years old as of 2006), growing in a northern temperate climate. The data were used to estimate annual ecosystem respiration (Re) and its component fluxes, including soil, foliar, and woody tissue respiration; to investigate major environmental factors causing intersite and temporal variability in the observed fluxes; and to compare chamber‐based Re estimates with eddy covariance‐based estimates. While temperature was the dominant driving factor of temporal variability in component fluxes, intersite variability in CO2 emissions was attributed to differences in stand physiological characteristics, such as the presence of the LFH soil horizon, its carbon‐to‐nitrogen ratio, and the amount of canopy cover. Additional factors that contributed to flux variability included the frequency of precipitation events, vapor pressure deficit and stem diameter, depending on the component considered. Estimated annual chamber‐based totals of Re across the four stands were 1526 ± 137, 1278 ± 137, 1985 ± 293, and 773 ± 46 g C m−2 yr−1 for the 67‐, 32‐, 17‐, and 4‐year‐old stands, respectively. Soil respiration dominated emissions at the 4‐year‐old stand, while foliar respiration dominated emissions at the 17‐year‐old stand. In contrast, at the two oldest stands, soil and foliar respirations were comparable. Soil respiration accounted for 44%, 44%, 26%, and 70% of annual Re, across the 67‐, 32‐, 17‐, and 4‐year‐old stands, while foliar respiration accounted for 48%, 41%, 60%, and 30% of annual Re, across the respective sites. Wood respiration was the smallest component of annual Re across the stands (8%, 15%, 14%, and 0.1%, respectively). The chamber‐based Re values were higher than tower‐based eddy covariance Re estimates, on average by 18%, 70%, 18%, and 36% at the 67‐, 32‐, 17‐, and 4‐year‐old stands, respectively. This study contributes to our general understanding of the age‐related effects and the role of climate on carbon emissions from various components of afforested ecosystems. Our results suggest that foliar respiration could be comparable to or higher than soil respiration in its contribution to Re in young to mature, planted or afforested, ecosystems. They also suggest that site quality and stand age are important factors to be considered in future studies of carbon dynamics of afforested stands.
A Shift in Scientific Literacy: Earthquakes Generate Tsunamis
Authors: Clark Scott K.
Published: September 2010

Scientific literacy is a fundamentally important prerequisite for decision making in this global age, particularly when it comes to decisions that affect our health, environment, technological advancement, and community development. A scientifically literate populace should be proficient at reading and interpreting science news articles [National Research Council, 1996]. For this to occur, terminology in news reports needs to be scientifically accurate.

As scientists, we often resign ourselves to the reality that scientific accuracy in mainstream news reports sometimes falls short of what we would hope. However, in at least one case, the use of appropriate terminology in news reports has clearly improved. Prior to the devastating 26 December 2004 Indian Ocean earthquake and tsunami, nearly one in four newspaper and wire service articles that discussed earthquakes and tsunamis exclusively used the term “tidal wave” in lieu of “tsunami.” That ratio has decreased to less than one in 35 since the 26 December 2004 event. The apparent permanence of this lexical shift is demonstrated by the nearly unanimous use of the term tsunami in media reports of the 12 January 2010 Haitian and 27 February 2010 Chilean tsunamis, and provides an example of the impact natural disasters can have on scientific discourse in the news media.
Science for Humanity: Giving Generously to Our World
Authors: Sparks R. Stephen J.
Published: September 2010

Hardly a week goes by without some reminder that we live in an age of anxiety and a world in environmental crisis. As I write this message, unusual stratospheric wind patterns in the Northern Hemisphere seem to be implicated in tragic floods in Pakistan, landslides in China, and wildfires near Moscow. The oil spill in the Gulf of Mexico reminds us of our dependence on oil, the increasing scarcity of natural resources, and the adverse environmental impact of our appetite for these resources.

The Haiti earthquake earlier this year demonstrates the vulnerability of human society to the natural world. So does the small volcanic eruption in Iceland that disrupted the travel plans of millions of people and cost the aviation industry billions of dollars. Our vulnerability seems to be increasing as the world's population continues to grow, as globalization and interdependencies advance at a giddy pace, and as human societies strive for economic growth.
Climate change and thresholds of biome shifts in Amazonia
Authors: Salazar Luis Fernando , Nobre Carlos A.
Published: September 2010

We examine potential critical thresholds for biome shift in the Amazonian tropical forest by forcing a potential vegetation model with prescribed climate anomalies and projections from global and regional climate models and different levels of CO2 fertilization effect under the SRES A2 scenario (2070–2099). The results indicate that tropical forests might be replaced by seasonal forests or savanna over eastern Amazonia with temperature increases of 2–3°C (4–5°C), when CO2 fertilization effect is not considered (partially considered), depending on precipitation anomaly. A precipitation decrease greater than 30% would trigger the shift from tropical forest to drier biomes, such as savanna and shrubland in southeastern Amazonia. The projected decrease in precipitation during the dry season and the increase of temperature are the main mechanisms driving calculated biome changes. However, biome changes are considerably smaller when the optimum fertilization effect is included.
Lake Toba volcano magma chamber imaged by ambient seismic noise tomography
Authors: Stankiewicz Jacek , Ryberg Trond , Haberland Christian , Fauzi  , Natawidjaja Danny
Published: September 2010

For the first time, ambient noise tomography is used to clearly image the magma chamber beneath Lake Toba caldera, one of the largest Quaternary calderas on Earth. Using data from 40 seismic stations deployed between May and October 2008 around Lake Toba, empirical Green's functions are extracted from long term cross‐correlations of continuous records. These functions are dominated by Rayleigh waves, whose group velocities can be measured in the period range from 2.5 to 12 seconds. Arrival times of these waves are picked for a given period and inverted using 2‐D tomography to calculate lateral variations in velocity for the given period. This was done for six different periods, which all correspond to different sampling depths. Thus the six 2‐D models presented together provide information on velocity variations with depth. The results show a low‐velocity body coincident with the Lake Toba caldera, representing the magma chamber under the volcano. The chamber is observed to have a complex 3‐D geometry, with at least two separate sub‐chambers underlying the caldera. Other results include a deep low velocity body, possibly another magma chamber, south west of the lake with an upper limit of ∼7 km depth. The maximum depth to which this body reaches could not be resolved. The Sumatra Fault marks a velocity contrast, but only down to depths not greater than 5 km. The reliability of the results was further confirmed by checkerboard recovery tests.
Ducting characteristics of Pc 1 waves at high latitudes on the ground and in space
Authors: Kim H. , Lessard M. R. , Engebretson M. J. , Lühr H.
Published: September 2010

Well‐defined ULF Pc 1 geomagnetic pulsations have been observed simultaneously from a ground array of five search‐coil magnetometers in the morning sector of Antarctica on Mar. 23, 2007. Distributed over a very extensive range of geomagnetic latitudes (−62° to −87°, spanning ∼2920 km geographically) approximately along a magnetic meridian, the array showed poleward propagation of the Pc 1 waves in the ionospheric waveguide. It is observed that attenuation factors are between ∼8 and 20 dB/1000 km and the polarization sense changes from left‐hand to right‐hand as the waves are ducted poleward. However, a complex polarization pattern (i.e., change in ellipticity and major axis angle) was seen on the ground, which might be attributed to the array being close to the wave injection region where the superposed effect of incident waves and ducted waves is dominant. A CHAMP satellite conjunction showed a transverse and nearly linearly polarized Pc 1 ULF wave at the altitude of the ducting layer (∼350 km) over a limited latitudinal extent (−53° to −61° ILAT). The polarization analysis performed using the ground data supports the idea that CHAMP detected the wave activity near the wave injection region. The observations are unique in that the ducted waves, seen over an array with unprecedented geomagnetic latitudinal range and positioning along a magnetic meridian (a condition that provides the most efficient ducting), have rarely been measured before.
SATB2 augments ΔNp63α in head and neck squamous cell carcinoma
Authors: Chung Jacky , Lau Joanne , Cheng Lynn S , Grant R Ian , Robinson Fiona , Ketela Troy , Reis Patricia P , Roche Olga , Kamel‐Reid Suzanne , Moffat Jason , Ohh Michael , Perez‐Ordonez Bayardo , Kaplan David R , Irwin Meredith S
Published: September 2010

ΔNp63α is a critical pro‐survival protein overexpressed in 80% of head and neck squamous cell carcinomas (HNSCCs) where it inhibits TAp73β transcription of p53‐family target genes, which is thought to increase HNSCC resistance to chemotherapy‐induced cell death. However, the mechanisms governing ΔNp63α function are largely unknown. In this study, we identify special AT‐rich‐binding protein 2 (SATB2) as a new ΔNp63α‐binding protein that is preferentially expressed in advanced‐stage primary HNSCC and show that SATB2 promotes chemoresistance by enhancing ΔNp63α‐mediated transrepression by augmenting ΔNp63α engagement to p53‐family responsive elements. Furthermore, SATB2 expression positively correlates with HNSCC chemoresistance, and RNA interference‐mediated knockdown of endogenous SATB2 re‐sensitizes HNSCC cells to chemotherapy‐ and γ‐irradiation‐induced apoptosis, irrespective of p53 status. These findings unveil SATB2 as a pivotal modulator of ΔNp63α that governs HNSCC cell survival.
Listening to public concerns about human life extension
Authors: Partridge Brad , Lucke Jayne , Hall Wayne
Published: September 2010

Technologies to extend the human life span have gained media, scientific and commercial attention, but the public remains cautious. This wariness may in part be caused by the failure of scientists to communicate what is known and unknown about ageing.
Dimensionality Reduction on Multi-Dimensional Transfer Functions for Multi-Channel Volume Data Sets
Authors: Kim Han Suk , Schulze Jürgen P. , Cone Angela C. , Sosinsky Gina E. , Martone Maryann E.
Published: September 2010

The design of transfer functions for volume rendering is a non-trivial task. This is particularly true for multi-channel data sets, where multiple data values exist for each voxel, which require multi-dimensional transfer functions. In this article, we propose a new method for multi-dimensional transfer function design. Our new method provides a framework to combine multiple computational approaches and pushes the boundary of gradient-based multidimensional transfer functions to multiple channels, while keeping the dimensionality of transfer functions at a manageable level, that is, a maximum of three dimensions, which can be displayed visually in a straightforward way. Our approach utilizes channel intensity, gradient, curvature and texture properties of each voxel. Applying recently developed nonlinear dimensionality reduction algorithms reduce the high-dimensional data of the domain. In this article, we use Isomap and Locally Linear Embedding as well as a traditional algorithm, Principle Component Analysis. Our results show that these dimensionality reduction algorithms significantly improve the transfer function design process without compromising visualization accuracy. We demonstrate the effectiveness of our new dimensionality reduction algorithms with two volumetric confocal microscopy data sets.
Self-organization and symmetry-breaking in two-dimensional plasma turbulence
Authors: Bos Wouter J. T. , Neffaa Salah , Schneider Kai
Published: September 2010

The spontaneous self-organization of two-dimensional magnetized plasma is investigated within the framework of magnetohydrodynamics with a particular emphasis on the symmetry-breaking induced by the shape of the confining boundaries. This symmetry-breaking is quantified by the angular momentum, which is shown to be generated rapidly and spontaneously from initial conditions free from angular momentum as soon as the geometry lacks axisymmetry. This effect is illustrated by considering circular, square, and elliptical boundaries. It is shown that the generation of angular momentum in nonaxisymmetric geometries can be enhanced by increasing the magnetic pressure. The effect becomes stronger at higher Reynolds numbers. The generation of magnetic angular momentum (or angular field), previously observed at low Reynolds numbers, becomes weaker at larger Reynolds numbers.
Two hard spheres in a pore: Exact statistical mechanics for different shaped cavities
Authors: Urrutia Ignacio
Published: September 2010

The partition function of two hard spheres in a hard-wall pore is studied, appealing to a graph representation. The exact evaluation of the canonical partition function and the one-body distribution function in three different shaped pores are achieved. The analyzed simple geometries are the cuboidal, cylindrical, and ellipsoidal cavities. Results have been compared with two previously studied geometries; the spherical pore and the spherical pore with a hard core. The search of common features in the analytic structure of the partition functions in terms of their length parameters and their volumes, surface area, edges length, and curvatures is addressed too. A general framework for the exact thermodynamic analysis of systems with few and many particles in terms of a set of thermodynamic measures is discussed. We found that an exact thermodynamic description is feasible based on the adoption of an adequate set of measures and the search of the free energy dependence on the adopted measure set. A relation similar to the Laplace equation for the fluid-vapor interface is obtained, which expresses the equilibrium between magnitudes that in extended systems are intensive variables. This exact description is applied to study the thermodynamic behavior of the two hard spheres in a hard-wall pore for the analyzed different geometries. We obtain analytically the external reversible work, the pressure on the wall, the pressure in the homogeneous region, the wall-fluid surface tension, the line tension, and other similar properties.
Kinetics and mechanism of the unfolding native-to-loop transition of Trp-cage in explicit solvent via optimized forward flux sampling simulations
Authors: Velez-Vega Camilo , Borrero Ernesto E. , Escobedo Fernando A.
Published: September 2010

The native-to-loop (N-L) unfolding transition of Trp-cage protein was studied via optimized forward flux sampling (FFS) methods with trajectories evolved using molecular dynamics. The rate constant calculated from our simulations is in good agreement with the experimental value for the native-to-unfolded transition of this protein; furthermore, the trajectories sampled a phase region consistent with that reported in previous studies for the N-L transition using transition path sampling and transition interface sampling. A new variant of FFS is proposed and implemented that allows a better control of a constant flux of partial paths. A reaction coordinate model was obtained, at no extra cost, from the transition path ensemble generated by FFS, through iterative use of the FFS-least-square estimation method [E. E. Borrero and F. A. Escobedo, J. Chem. Phys. 127, 164101 (2007)] and an adaptive staging optimization algorithm [E. E. Borrero and F. A. Escobedo, J. Chem. Phys. 129, 024115 (2008)]. Finally, we further elucidate the unfolding mechanism by correlating the unfolding progress with changes in the root mean square deviation from the α carbons of the native state, the root mean square deviation from an ideal α-helix, and other structural properties of the protein.
Role of OH radicals in the formation of oxygen molecules following vacuum ultraviolet photodissociation of amorphous solid water
Authors: Hama Tetsuya , Yokoyama Masaaki , Yabushita Akihiro , Kawasaki Masahiro
Published: September 2010

Photodesorption of O2(X Σ3g−) and O2(a Δ1g) from amorphous solid water at 90 K has been studied following photoexcitation within the first absorption band at 157 nm. Time-of-flight and rotational spectra of O2 reveal the translational and internal energy distributions, from which production mechanisms are deduced. Exothermic and endothermic reactions of OH+O(P3) are proposed as plausible formation mechanisms for O2(X Σ3g− and a Δ1g). To examine the contribution of the O(P3)+O(P3) recombination reaction to the O2 formation following 157 nm photolysis of amorphous solid water, O2 products following 193 nm photodissociation of SO2 adsorbed on amorphous solid water were also investigated.
Identification and thermal stability of the native oxides on InGaAs using synchrotron radiation based photoemission
Authors: Brennan B. , Hughes G.
Published: September 2010

A high resolution synchrotron radiation core level photoemission study of the native oxides on In0.53Ga0.47As was carried out in order to determine the various oxidation states present on the surface. The thermal stability of the oxidation states was also investigated by annealing the samples in vacuum at temperatures ranging from 150 to 450 °C. As well as the widely reported oxidation states, various arsenic, gallium, and indium oxides, along with mixed phase gallium arsenic and indium gallium oxides are identified. Elemental binary oxides have been identified as residing at the oxide substrate interface and could play an important role in understanding the growth of metal oxide dielectric layers on the InGaAs surface, due to their apparent chemical stability.