bluuebunny/crossref_metadata_2025 huggingface dataset:
Teleoperation with kinematically redundant robot manipulators with sub-task objectives
Authors: Nath Nitendra , Tatlicioglu Enver , Dawson Darren M.
Published: March 2009

In this paper, control of nonlinear teleoperator systems where both the master and slave systems are kinematically redundant robot manipulators is addressed. The controller is developed under the assumption that the user and environmental input forces are unmeasurable. Lyapunov-based stability analysis is used to prove that the proposed controller yields asymptotic tracking results and ensures the coordination of the master and slave systems while satisfying a sub-task objective. Numerical simulation results are presented to illustrate the effectiveness of the proposed controller.
CONVERGENCE TO STOCHASTIC POWER INTEGRALS FOR DEPENDENT HETEROGENEOUS PROCESSES
Authors: Sandberg Rickard
Published: March 2009

Building on work of Hansen (1992,Econometric Theory8, 489–501), we show weak convergence for power transformations of integrated processes, with possibly serially correlated and heterogeneously distributed increments, to stochastic power integrals. The theory is applicable when testing the unit root or cointegration hypothesis in nonlinear systems by regression-based test statistics.
Influence of Income on Health Status and Healthcare Utilization in Working Adults: an Illustration of Health among the Working Poor in Japan
Authors: TOKUDA YASUHARU , OHDE SACHIKO , TAKAHASHI OSAMU , HINOHARA SHIGEAKI , FUKUI TSUGUYA , INOGUCHI TAKASHI , BUTLER JAMES P. , UEDA SHIGEYUKI
Published: March 2009

Little is known about health of the growing subpopulation of the working poor in Japan. We aimed to evaluate health status and healthcare utilization in relation to income among Japanese working adults. We conducted a one-month prospective cohort study using a health diary in working adults from a nationally representative random sample in Japan. Based on the government criterion, the working poor group was defined as earning an equivalent annual income of less than 1.48 million Japanese-yen. For health status, we measured symptomatic episodes and health-related quality of life (HRQOL). For healthcare utilization, we measured frequencies of visits to a physician or pharmacy, and use of complementary and alternative medicine (CAM). We constructed multiple linear regression models for these measures adjusted for age, gender, and co-morbidity, using annual equivalent income as a 4-level categorical variable.

Of 3,568 participants originally enrolled in the study panel, 3,477 completed the survey (response rate 97%). For the purpose of the study, of the 3,568 participants, we analyzed 1,406 working adults who were 20–65 years old (mean age, 40.8 yr: 58.4% men). There were 106 (7.5%) working poor: 56 men (6.8% of working men) and 50 women (8.5% of working women). Compared to the highest income group, the working poor reported the greater number of symptomatic episodes and a slightly lower score of physical component of HRQOL (PCS8). The numbers of symptomatic episodes among the working poor and the highest income group during the 1-month study period were 9.79 (SD, 8.77) and 7.01 (SD, 7.34), respectively (p < 0.01). The PCS8 among the working poor was 48.71 (SD, 7.05) and it was 50.34 (SD, 6.55) among the highest income group (p < 0.01). There was no difference of healthcare utilization by the different levels of income.

We concluded that the working poor (7.5% of all working adults) more frequently report symptomatic episodes and show slightly poorer physical health status, compared to the highest income group. Healthcare utilization is not affected by income.
Brazil – Measures Affecting Imports of Retreaded Tyres: A Balancing Act
Authors: BOWN CHAD P. , TRACHTMAN JOEL P.
Published: March 2009

This paper provides a legal-economic analysis of the Appellate Body decision inBrazil–Retreaded Tyres. We develop a simple economic model that we use to analyze the market structure and environmental externalities that were most relevant to this case. We start by analyzing Brazil's policies in a model in which tyre retreading generates a positive production externality through the delay it provides society before a used tyre becomes a waste product with the potential to harm society through its adverse impact on human health and the environment. We examine the different welfare implications of (i) a production subsidy for retreading of once-used Brazilian tyres, (ii) a tariff on imports of retreaded tyres, and (iii) a ban on imports of retreaded tyres. While a production subsidy is the first-best instrument to address this type of externality, there are reasons to believe that it might be infeasible. The welfare implications of the other measures depend importantly on the magnitude of the positive production externality. From the lens provided by this economic analysis, we draw three primary insights. First, we identify the critical piece of empirical information that the Panel and Appellate Body require to make a rational judgment of the utility of the Brazilian policies contested in the dispute – i.e., the size of the underlying externality associated with retreading. Second, if the justification for the original import ban on retreaded tyres was based on the argument that it was a second-best Brazilian policy designed to combat a large externality, then Brazil's failure to enforce a ban on used-tyre imports has the troubling result of eroding those potential welfare gains through a reduction in equilibrium production (and consumption) of Brazilian retreaded tyres. Third, the Brazilian policy that exempted from the ban retreaded imports from MERCOSUR partners also has the same troubling feature. The second and third points are congruent with the reasons for the Appellate Body's determination that the Brazilian policy did not qualify under the chapeau of Article XX. We examine the WTO jurisprudence of Article XX(b), in order to compare the methodology developed under this jurisprudence to the type of examination of changes to total welfare from implementing one policy relative to a postulated alternative policy that most economists would follow. We find that the WTO jurisprudence in this area is internally incoherent, and also fails to evaluate the types of concerns that an economic-welfare analysis would evaluate.
A One-Two Punch on Zeroing: US–Zeroing (EC) and US–Zeroing (Japan)
Authors: PRUSA THOMAS J. , VERMULST EDWIN
Published: March 2009

This paper examines issues that came before the Appellate Body in two disputes, US–Zeroing (EC) and the US–Zeroing (Japan). The core issue in both the disputes involves the US Department of Commerce's practice of zeroing. The scope of the claims in both cases was considerably broader than in the previous WTO disputes involving zeroing. The two arguments in support of the practice were that (a) the practice of zeroing has been a standard administrative practice for many years and (b) the Antidumping Agreement does not clearly prohibit it and hence deference must be given to national authorities. While, the Appellate Body was arguably correct in prohibiting the use of zeroing under the main methods of Article 2.4.2 AD Agreement as well as in various reviews, we consider that it overreached in considering zeroing to be in violation of Article 2.4 AD Agreement and possibly as inconsistent with Article 2.4.2, exceptional method. Finally, while the AB found zeroing in reviews violated Article 2.4.2 AD Agreement, we believe it would have been preferable for the AB to have limited its findings of inconsistency to Article 9.3 AD Agreement.
Japan – Countervailing Duties on Dynamic Random Access Memories from Korea (DS 336 and Corr.1, adopted 17 December 2007)
Authors: CROWLEY MEREDITH A. , PALMETER DAVID
Published: March 2009

This article analyzes the decision of the WTO's Appellate Body in the dispute between Japan and Korea over Japan's imposition of countervailing duties on DRAMs imported from Korea. The legal analysis comments on the analysis of evidence, the lack of remand authority in the WTO system, and the meaning of a ‘direct transfer of funds’. The economic analysis discusses several issues related to determining the magnitude of the benefit to a firm of a financial bailout and the appropriate duration of a countervailing duty to offset the injury caused by a non-recurrent subsidy. We offer legal and economic criticisms of the Appellate Body's conclusion regarding the relationship between subsidies and injury to the domestic import-competing industry. We conclude that the Appellate Body's decision weakens the requirement of a causal link between subsidies and injury and, consequently, may open the door to protectionist abuse of the Subsidies and Countervailing Measures Agreement.
Rice Age: Comments on the Panel Report in Turkey – Measures Affecting the Importation of Rice
Authors: GANTZ DAVID A. , SCHROPP SIMON A. B.
Published: March 2009

At face value, Turkey–Rice is not the most complex or important WTO dispute ever litigated. The facts of the case give strong reason to believe that Turkey's restrictions on rice imports from the United States were not GATT-consistent. Turkey's steadfast refusal to provide exonerating evidence in its defence and the Panel's drawing of appropriate inference were probably the most remarkable issues of the case. Nevertheless, Turkey–Rice raises at least one interesting legal and economic question: How ‘activist’ are dispute panels today, and how interventionist should they be during the litigation process? We discuss the justification and role of activist panels and assess the consequences for parties' strategic behavior and incentive to provide accurate information.
Inter-family distant hybridization of Oryza sativa and Oenothera biennis
Authors: Xiu-Cheng Chu , Ji-Hong Zhao , Yang Chai , Jian-Feng Zhao , Yun-Yang Zhao , Li-Yan Jiang , Fen-Shan Zhao , Hui-Qin Yu , Wei-Dong Zhao , Zhi-Qiang You
Published: March 2009

Progenies derived from rice (Oryza sativa ssp. japonica) plants pollinated by Oenothera biennis exhibited numerous morphological and developmental traits. Some variant individuals appeared in generation D2. From generations D3 to D6, a large number of variants were observed, showing distinct variable traits including giant embryos. Statistical analysis on D6 lines showed significant differences between progenies and their rice parental line in several main traits, including plant height (49.2–164.5 cm), panicle number (12.1–38.2), panicle length (20.3–30.3 cm), length of sword leaf (13.8–57.5 cm), leaf width (11.1–25.2 mm), grain number of main panicle (142.0–367.0), percentage of seed setting (0.8–99.0%), 1000-grain weight (19.7–33.8 g) and time from germination to panicle emergence (90.0–108.0 days). Most of the variable coefficients were above 20% (the highest was 40.8%). Through pedigree selection of these plants, genetically stable lines were obtained, which are useful for rice breeding. Results from amplified fragment length polymorphism (AFLP) analysis showed that several rice lines contained extensive genetic variations, which included disappearance of rice parental bands and/or appearance of novel bands.
SSR markers for identification of purity of melon hybrids
Authors: Ju-Fen Li , Guo-Bin Ma , Ling Xu
Published: March 2009

The hybrid purity of melon (Cucumis melo L.) was tested by polymerase chain reaction (PCR) assay based on simple sequence repeat (SSR) markers in two F1 melon hybrids (‘Dongfangmi 1’ and ‘Dongfangmi 2’) and their parental lines. Twelve pairs of SSR primers for ‘Dongfangmi 1’ and three pairs for ‘Dongfangmi 2’ were selected. Results showed that self-inbred seeds were effectively distinguished from F1 hybrid seeds using these SSR primers, a finding that was consistent with the results recorded from field tests. ‘Dongfangmi 1’ and ‘Dongfangmi 2’ were identified from their parental lines, and seven other uterine hybrid lines by multiplex primers MS48+MS60 and MS4+MS20, respectively. Contamination of F1 hybrid seeds caused by self-inbred and other unknown pollens can be effectively and more reliably detected by PCR assays with multiplex SSR primers.
Diversity analysis of endophytic bacteria withinAzolla microphyllausing PCR-DGGE and electron microscopy
Authors: Si-Ping Zheng , Bin Chen , Xiong Guan , Wei-Wen Zheng
Published: March 2009

Using 16S rDNA-polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE), electron microscopy and a conventional plating method, the genetic diversity and phenotype polymorphism of the endophytic bacteria withinAzolla microphyllawere explored. The 16S rDNA-PCR-DGGE profile showed a complex and divergent bacterial community, withBacillus cereusas the dominant species, within theAzolla–cyanobacteria association. This result was supported by the fact that endobacterial cells exhibited distinct ultrastructural characteristicsin vivoand,in vitro, bacteria displayed various colonies with different sizes, shapes and colours. This study demonstrates that the genetic diversity of endophytic bacteria inAzollacan be investigated using the16S rDNA-PCR-DGGE technique.
Vertical displacement detection of an aluminum nitride piezoelectric thin film using capacitance measurements
Authors: Al Ahmad Mahmoud , Plana Robert
Published: March 2009

Piezoelectric materials have a strong interaction between their mechanical and electrical properties that translates into innovative components and circuits architectures. This work describes an original method using the electromechanical properties of the aluminum nitride (AlN) piezoelectric material to characterize its vertical extension when an electric field is applied. The novel techniques based on measurements of a planar parallel plate AlN capacitor without and with bias employing an impedance analyzer. The parallel plate capacitor theory and piezoelectric material analysis are used to calculate the vertical displacement of the AlN film.
Bindehautentzündung
Authors: Meyer Peter , Messerli Jürg
Published: March 2009

Entzündungen der Bindehaut zählen zu den häufigsten Augenerkrankungen beim Grundversorger und in der augenärztlichen Praxis. Ätiologisch liegen zahlreiche verschiedene Krankheiten zugrunde. Infektiöse Konjunktivitiden werden einer sehr heterogenen Gruppe nicht infektiöser gegenüber gestellt. Auch neoplastische Prozesse wie beispielsweise beginnende epitheliale Dysplasien und Lymphome können sich als Konjunktivitis maskieren. Die Abgrenzung der verschiedenen Krankheitsbilder kann den Praktiker vor Probleme stellen. Dieser Artikel gibt einen Überblick über die Anamnese und Untersuchungsmethoden allgemein sowie die Symptomatalogie und Behandlung wichtiger Bindehautentzündungen in der Praxis.
Augenerkrankungen bei Diabetes mellitus
Authors: Prahs Philipp , Helbig Horst
Published: March 2009

Die diabetische Retinopathie ist die häufigste Erblindungsursache von Personen im erwerbsfähigen Alter in der industrialisierten Welt. Eine rechtzeitige gute Stoffwechseleinstellung mit Behandlung begleitender vaskulärer Risikofaktoren reduziert das individuelle Risiko erheblich. Regelmäβige augenärztliche Screening-Untersuchungen auch asymptomatischer Diabetiker sind notwendig, um eine rechtzeitige Therapie sicherzustellen, da eine bereits eingetretene Reduktion der Sehschärfe oftmals irreversibel ist. Die augenärztliche Behandlung ist indiziert beim Auftreten von Gefäβproliferationen (Neovaskularisationen) auf der Netzhaut, die zu Glaskörperblutungen und traktiven Netzhautablösungen führen können. Durch die panretinale Laserkoagulation wird das Verhältnis zwischen Sauerstoffverbrauch und –angebot verbessert und damit der Stimulus für Neovaskularisationen reduziert. Bei Auftreten eines diabetischen Makulaödems können parazentrale Laserkoagulationen oder gegebenenfalls intravitreale Medikamenteninjektionen zur Stabilisierung der Kapillarpermeabilität und Erhalt der Sehschärfe durchgeführt werden. In fortgeschrittenen Stadien muss die Entscheidung zum chirurgischen Vorgehen mit der Pars-plana-Vitrektomie individuell getroffen werden.
Notfälle in der Augenheilkunde
Authors: Schrader Wolfgang F.
Published: March 2009

Spontan auftretende Situationen wie auch exogene (durch äuβere Einwirkung entstandene) Ursachen können von einer Minute zur nächsten das Sehvermögen akut bedrohen. Je nach Symptomatik kann es sich dabei um spontan auftretende Notfallsituationen handeln (z.B. akute arterielle oder venöse Durchblutungsstörung, Glaskörperblutung oder eine Netzhautablösung), oder um eine äuβere Einwirkung (z.B. durch Verletzungen) entstandene. Diese Notfallsituationen werden im Folgenden systematisch vorgestellt.
Besonderheiten bei der Amputation der unteren Extremität aus der Sicht des Internisten
Authors: Lobmann  , Motzkau  , Wagner  , Lehnert
Published: March 2009

Amputationen sind nicht nur für den Chirurgen ein relevantes Alltagsproblem. Insbesondere sind Internisten und Diabetologen speziell beim diabetischen Fußsyndrom in die Wundbehandlung, die Koordination der die Wundheilung beeinträchtigenden Begleitumstände (z.B. Hyperglykämie, Infektion, Durchblutungsstörung) und in die interdisziplinäre Entscheidungsfindung zur notwendigen Amputation aktiv mit eingebunden. Ein strukturiertes interdisziplinäres Procedere hilft die, gerade beim Diabetiker, auftretenden Wundheilungsstörungen zu beherrschen und auch mit minimal-chirurgischen Interventionen ein funktionell optimales Ergebnis für den Patienten zu erreichen.
Majoramputationen beim Gefäßpatienten
Authors: Hepp
Published: March 2009

Zur Rehabilitation nach Majoramputation ist ein möglichst langer Stumpf mit guter Wundheilung erforderlich. Beim Gefäßpatienten sind dafür folgende Absetzungshöhen mit spezieller Technik erforderlich: Syme-Amputation, Unterschenkelamputation, Knieexartikulation, Oberschenkelamputation und ganz selten Hüftexartikulation. Indikation, Techniken und Nachbehandlung werden dargestellt.
Möglichkeiten und Grenzen der Plastischen Chirurgie
Authors: Fuchs  , Pallua
Published: March 2009

Die demographischen Veränderungen in unserer Bevölkerung machen sich in jedem Fach innerhalb der modernen Medizin bemerkbar. Lag ein Schwerpunkt in der plastisch-chirurgischen Versorgung noch vor wenigen Jahren in der Wiederherstellung nach Traumata verschiedenster Genese, rückt heute auch mehr und mehr die Versorgung typischer Alters- und Wohlstandserkrankungen in den Mittelpunkt. Hierbei spielt der Erhalt der unteren Extremität eine herausragende Rolle. Insbesondere bei Diabetikern in der typischen Verbindung mit einer peripheren Verschlusskrankheit kommt es zu Ulzerationen und Defekten im Fuß- und Unterschenkelbereich, welche die Zusammenarbeit zwischen Diabetologie, Gefäßchirurgie und Plastischer Chirurgie zum Extremitätenerhalt erfordern.
Incorporating self‐consistently calculated mineral physics into thermochemical mantle convection simulations in a 3‐D spherical shell and its influence on seismic anomalies in Earth's mantle
Authors: Nakagawa Takashi , Tackley Paul J. , Deschamps Frederic , Connolly James A. D.
Published: March 2009

Phase assemblages of mantle rocks calculated from the ratios of five oxides (CaO‐FeO‐MgO‐Al2O3‐SiO2) by free energy minimization were used to calculate the material properties density, thermal expansivity, specific heat capacity, and seismic velocity as a function of temperature, pressure, and composition, which were incorporated into a numerical thermochemical mantle convection model in a 3‐D spherical shell. The advantage of using such an approach is that thermodynamic parameters are included implicitly and self‐consistently, obviating the need for ad hoc parameterizations of phase transitions which can be complex in regions such as the transition zone particularly if compositional variations are taken into account. Convective planforms for isochemical and thermochemical cases are, however, not much different from those computed using our previous, simple parameterized reference state, which means that our previous results are robust in this respect. The spectrum and amplitude of seismic velocity anomalies obtained using the self‐consistently calculated material properties are more “realistic” than those obtained when seismic velocity is linearly dependent on temperature and composition because elastic properties are dependent on phase relationship of mantle minerals, in other words, pressure and temperature. In all cases, the spectra are dominated by long wavelengths (spherical harmonic degree 1 to 2), similar or even longer wavelength than seismic tomographic models of Earth, which is probably due to self‐consistent plate tectonics and depth‐dependent viscosity. In conclusion, this combined approach of mantle convection and self‐consistently calculated mineral physics is a powerful and useful technique for predicting thermal‐chemical‐phase structures in Earth's mantle. However, because of uncertainties in various parameters, there are still some shortcomings in the treatment of the postperovskite phase transition. Additionally, transport properties such as thermal conductivity and viscosity are not calculated by this treatment and are thus subject to the usual uncertainties.
Internal wave induced dispersion and mixing on a sloping boundary
Authors: Inall Mark E.
Published: March 2009

A fluorescent dye‐tracer was released in a stratified water column above a sloping boundary revealing profound dispersive asymmetry. Initially the dye spread symmetrically in the vertical until the deeper portion became influenced by the bottom boundary layer (BBL). The shallower portion then spread rapidly up‐slope in a thin boundary layer influenced by highly non‐linear isopycnal distortions. The deeper, down‐slope portion of dye subsequently became detached from the boundary and intruded into the basin interior in three distinct layers along isopycnal surfaces. The intrusions result from the gravitational collapse of mixing patches created by baroclinic flow over an irregular boundary. The vertical separation of the layers matches the inverse topographic wavenumber. Up‐slope displacement of the dye is consistent with an advective/diffusive balance near the sloping boundary, controlled by slope angle and roughness. Horizontal diffusivities increased from 1.4 m2s−1 to 18.4 m2s−1 during the 4‐day experiment.
Solar cycle variations of heliospheric magnetic flux
Authors: Zhou Xiaoyan , Smith Edward J.
Published: March 2009

We extend previous studies of BR, the radial component of the heliospheric magnetic field and a measure of heliospheric magnetic flux, to include the maximum in cycle 23 so that most of 4 cycles are covered. Solar rotation averages reveal that BR systematically increases from a minimum value at sunspot minimum to a maximum value during the declining phase. This increase is interrupted by a temporary decrease associated with the disappearance and reversal of the Sun's polar cap fields. We examine variations in BR and field strength, B, and find a close correspondence consistent with the Parker model when allowance is made for the ever‐present fluctuations in the heliospheric magnetic field. The solar cycle variation in BR and B is consistent with the widely accepted model of the solar field in which bipolar sunspot fields emerging at solar maximum are responsible for the erosion and reversal of the polar cap fields. Although the solar cycle change in heliospheric magnetic flux is less than a factor of 2, it is very large compared with the average flux transported into the heliosphere by an interplanetary coronal mass ejection (ICME). If the increases in B and BR at solar maximum are attributed to closed ICME fields, several hundred ICMEs must connect to the Sun for about two solar rotations before disconnecting, consistent with a recent model that attributes the increase in heliospheric flux at solar maximum to ICMEs. Future studies must distinguish between the open and closed topologies in order to evaluate their relative contributions.
Time‐dependent global MHD simulations of Cassini T32 flyby: From magnetosphere to magnetosheath
Authors: Ma Y. J. , Russell C. T. , Nagy A. F. , Toth G. , Bertucci C. , Dougherty M. K. , Neubauer F. M. , Wellbrock A. , Coates A. J. , Garnier P. , Wahlund J.‐E. , Cravens T. E. , Crary F. J.
Published: March 2009

When the Cassini spacecraft flew by Titan on 13 June 2007, at 13.6 Saturn local time, Titan was directly observed to be outside Saturn′s magnetopause. Cassini observations showed dramatic changes of magnetic field orientation as well as other plasma flow parameters during the inbound and outbound segments. In this paper, we study Titan's ionospheric responses to such a sudden change in the upstream plasma conditions using a sophisticated multispecies global MHD model. Simulation results of three different cases (steady state, simple current sheet crossing, and magnetopause crossing) are presented and compared against Cassini Magnetometer, Langmuir Probe, and Cassini Plasma Spectrometer observations. The simulation results provide clear evidence for the existence of a fossil field that was induced in the ionosphere. The main interaction features, as observed by the Cassini spacecraft, are well reproduced by the time‐dependent simulation cases. Simulation also reveals how the fossil field was trapped during the interaction and shows the coexistence of two pileup regions with opposite magnetic orientation, as well as the formation of a pair of new Alfven wings and tail disconnection during the magnetopause crossing process.
Upper equatorial Atlantic variability during 2002 and 2005 associated with equatorial Kelvin waves
Authors: Hormann Verena , Brandt Peter
Published: March 2009

On the basis of moored (35°W, 0° and 23°W, 0°) and satellite observations, we contrast the upper equatorial Atlantic variability during 2002 with those during 2005. Inspection of the interannual boreal summer cold tongue variability revealed a warm (cold) event in 2002 (2005), with relaxed (intensified) winds in the west and the Equatorial Undercurrent (EUC) embedded in a shallower (deeper) thermocline at 23°W. During both years, 2002 and 2005, equatorial Kelvin waves are present in moored observations as 20°C isotherm depth anomalies and dynamic height anomalies. Basin‐wide sea surface height anomalies are used to derive an equatorial Kelvin wave mode. The time evolution of this mode represents the basis for a regression analysis to investigate related oceanic variability: Compared to the exceptionally strong wave activity in 2002, equatorial Kelvin waves were generally weaker during 2005. The main effect of equatorial Kelvin waves on zonal velocity anomalies at 23°W, 0° is evident well below the EUC core. Their direct influence on cold tongue sea surface temperature is small, but they are found to affect the equatorial thermocline slope. Prior to the cold tongue onset in 2002 (2005), the presence of equatorial Kelvin waves is associated with a flattened (steeper) thermocline slope that is crucial for the shallowing (deepening) of the EUC core at 23°W and that might precondition the development of the warm (cold) event.
Comprehensive isotopic composition of atmospheric nitrate in the Atlantic Ocean boundary layer from 65°S to 79°N
Authors: Morin S. , Savarino J. , Frey M. M. , Domine F. , Jacobi H.‐W. , Kaleschke L. , Martins J. M. F.
Published: March 2009

The comprehensive isotopic composition of atmospheric nitrate (i.e., the simultaneous measurement of all its stable isotope ratios: 15N/14N, 17O/16O and 18O/16O) has been determined for aerosol samples collected in the marine boundary layer (MBL) over the Atlantic Ocean from 65°S (Weddell Sea) to 79°N (Svalbard), along a ship‐borne latitudinal transect. In nonpolar areas, the δ15N of nitrate mostly deriving from anthropogenically emitted NOx is found to be significantly different (from 0 to 6‰) from nitrate sampled in locations influenced by natural NOx sources (−4 ± 2)‰. The effects on δ15N(NO3−) of different NOx sources and nitrate removal processes associated with its atmospheric transport are discussed. Measurements of the oxygen isotope anomaly (Δ17O = δ17O − 0.52 × δ18O) of nitrate suggest that nocturnal processes involving the nitrate radical play a major role in terms of NOx sinks. Different Δ17O between aerosol size fractions indicate different proportions between nitrate formation pathways as a function of the size and composition of the particles. Extremely low δ15N values (down to −40‰) are found in air masses exposed to snow‐covered areas, showing that snowpack emissions of NOx from upwind regions can have a significant impact on the local surface budget of reactive nitrogen, in conjunction with interactions with active halogen chemistry. The implications of the results are discussed in light of the potential use of the stable isotopic composition of nitrate to infer atmospherically relevant information from nitrate preserved in ice cores.
A multiproxy index of the El Niño–Southern Oscillation, A.D. 1525–1982
Authors: Braganza Karl , Gergis Joëlle L. , Power Scott B. , Risbey James S. , Fowler Anthony M.
Published: March 2009

An understanding of past variability in the El Niño–Southern Oscillation (ENSO), on interannual, interdecadal, and longer time scales, would be useful in assessing recent observed changes to ENSO and in determining the realism of climate model simulations. Using tree ring, coral, and ice core data, we reconstruct a proxy‐based ENSO index between A.D. 1525 and 1982. Unlike most previous studies, which have drawn climate proxies from limited geographic regions, our network is Pacific basin–wide, using ENSO sensitive proxies from the western equatorial Pacific, New Zealand, the central Pacific, and subtropical North America. By considering multiple teleconnection regions, this network provides a more robust proxy ENSO signal. The common signal recorded in the multiproxy network has a high correlation with the Southern Oscillation Index (SOI), Niño 3.4 sea surface temperature (Niño3.4 SST), and a combined ocean‐atmosphere ENSO index (CEI). The proportion of instrumental variance explained is 47% for the SOI, 48% for Niño3.4 SST, and 52% for the CEI. The proxy ENSO index also displays skill in reproducing warm and cold extremes of the SOI. The proxy ENSO index over the last 450 years shows considerable amplitude and frequency modulation in the 3–10 year band on multidecadal time scales. There is a relative reduction in the amplitude of high‐frequency variability during the sixteenth, early seventeenth, and mid–eighteenth centuries. In contrast, high‐frequency ENSO variability has increased over the last 200 years. Variability during the first half of the twentieth century is similar to that evident in the nineteenth century.
Weekly cycle in particulate matter versus weekly cycle in precipitation over Switzerland
Authors: Barmet Peter , Kuster Thomas , Muhlbauer Andreas , Lohmann Ulrike
Published: March 2009

During the last few years the question has been raised if there is a weekly cycle in climatological variables due to anthropogenic activity. In this study, particulate matter (PM) data and precipitation data from 17 Swiss weather stations are analyzed for weekly cycles with three different methods: a nonparametric statistical test, a Fourier analysis on the time series, and a comparison of the regular 7‐day week with either a 6‐ or 8‐day week. Results show a well‐pronounced and statistical significant weekly cycle for PM but do not show any statistically significant weekly cycle for meteorological quantities such as precipitation.
Validation of MODIS Terra, AIRS, NCEP/DOE AMIP‐II Reanalysis‐2, and AERONET Sun photometer derived integrated precipitable water vapor using ground‐based GPS receivers over India
Authors: Prasad Anup K. , Singh Ramesh P.
Published: March 2009

Water vapor is an important and highly variable constituent in time and space; the knowledge of its variability is important in climate studies. In India, the ground observations of water vapor using conventional methods such as radiosonde are limited. In this paper, a comparison of hourly estimates of total column water vapor from Global Positioning System (GPS) with multisensor satellite is presented over three stations. We show quantitatively seasonal and monthly dependency of bias, standard deviation, root mean square error (RMSE), and the correlation coefficient between the water vapor data sets. The GPS and Aerosol Robotic Network (AERONET) water vapor show good agreement (R2 = 95%, RMSE 3.87 mm, GPS‐AERONET bias = −2.63 mm). On the basis of multiple‐year data, Moderate Resolution Imaging Spectroradiometer near‐infrared (MODIS NIR) clear column product shows higher correlation (R2 = 89–93%) with GPS compared to infrared (IR) products (R2 = 82–84%). MODIS is found to be overestimating in NIR clear and IR products in all seasons over India where the magnitude of bias and RMSE show systematic changes from month to month. MODIS is significantly underestimating in NIR cloudy column products during summer and monsoon seasons. MODIS NIR clear column (R2 = 97%, RMSE 5.44 mm) and IR (R2 = 81%, RMSE 7.17 mm) water vapor show similar performance on comparison with AERONET data. The MODIS NIR cloudy column product shows no correlation with GPS. The GPS National Centers for Environmental Prediction/Department of Energy Atmospheric Model Intercomparison Project II (GPS‐NCEP/DOE AMIP‐II) Reanalysis‐2 water vapor show R2 = 87%, 77%, and 60% (and RMSE of 8.39 mm, 6.97 mm, and 9.30 mm) over Kanpur, Hyderabad, and Bangalore, respectively. All the satellite water vapor shows systematic bias with month and season that is found to be sensitive to the sky conditions. The magnitude of bias is invariably larger during monsoon season with relatively more cloudy days and moist atmosphere. The errors in satellite estimation are found to be invariably more during wet compared to dry months. Statistical analysis shows that MODIS NIR clear column and Atmospheric Infrared Sounder (AIRS) daytime water vapor are more reliable compared to other satellite estimates (MODIS IR and AIRS nighttime) except during cloudy days.
A nonlocal theory of sediment buffering and bedrock channel evolution
Authors: Stark Colin P. , Foufoula‐Georgiou Efi , Ganti Vamsi
Published: March 2009

Bedrock erosion in mountain river channels ultimately sets the erosion rate of the surrounding hillslopes and the rate of sediment supply to the channels. The supply of coarse bed sediment acts as a dampening effect on further erosion by depositing an alluvial cover that temporarily obscures the bedrock. For landscapes where the residence time of the alluvial bed cover is comparable to the timescale of bedrock incision, coarse sediment supply and transport generate a strong negative feedback on fluvial downcutting and the coupled process of hillslope‐channel erosion is inherently self‐buffering. Here we study a simple model of self‐buffered bedrock channel erosion that incorporates the spreading of bed sediment cover downstream in a way that allows for a broad‐tailed, power law probability distribution of transport velocities of bed sediment over the long‐term. This leads us to consider a nonlocal transport law (fractional advection) parameterized by a scaling exponent 0 ≤ α < 1 which collapses to local advection for α → 1. For strong sediment buffering, we find that nonlocality 1 − α has a direct control on the power law scaling of channel slope S with upstream area A, giving S ∼ A−(1−α)/2 at steady state. Empirical observations of slope‐area scaling are consistent with α < 1 and nonlocal transport. In general, the model predicts linear, logarithmic, or power law stream profiles depending on the extent of buffering, the degree of nonlocality, and the scaling of the bedrock erosion law. It also predicts, somewhat counterintuitively, that bed cover should thicken with distance x downstream slower than linearly as xα, i.e., the more nonlocal the bed sediment spreading process (α → 0), the slower the bed cover increases downstream. We deduce that long‐range, heterogeneous transport of coarse sediment in mixed bedrock‐alluvial rivers may be a key element of landscape scaling and an important factor in landscape dynamics.
Numerical modeling of cosmogenic deglaciation records, Front Range and San Juan mountains, Colorado
Authors: Ward Dylan J. , Anderson Robert S. , Guido Zackry S. , Briner Jason P.
Published: March 2009

We use cosmogenic radionuclide (CRN) exposure ages from polished, striated bedrock to constrain numerical simulations of deglaciation in the Middle Boulder Creek Valley, Colorado Front Range, and the Animas River Valley, San Juan Mountains, Colorado. In both valleys, the cosmogenic ages suggest initiation of deglaciation ∼20 ka and ongoing retreat until 12–13 ka. While the first‐order trend in CRN concentrations in each valley suggests a monotonic glacial retreat, we evaluate other retreat scenarios with different implications for post‐Last Glacial Maximum regional climate. We use a 2‐D numerical glacier simulation with a CRN layer to investigate how CRN‐based deglaciation records are affected by retreat histories that are punctuated by periods of glacier readvance. The CRN layer simulates both production during periods of exposure and reduction by glacial erosion during readvances. We simulate glacial occupation of the valleys as they respond to equilibrium line altitude (ELA) histories characterized by stepwise change, gradual rise, or a rise punctuated by short periods of lowering. Each scenario generates a distinct spatial pattern of concentrations in the CRN layer. These results and the spatial pattern of measured concentrations in bedrock constrain the range of ELA histories that reproduce the CRN pattern in each valley. In the Animas River Valley, the exposure ages are well explained by a linear ELA rise from full glacial to deglacial conditions. Ages in Middle Boulder Creek Valley are best explained by a deglaciation history including a stillstand or partial readvance between 16 and 14 ka, followed by rapid retreat.
Phosphorylation of NF‐κB p65 at Ser468 controls its COMMD1‐dependent ubiquitination and target gene‐specific proteasomal elimination
Authors: Geng Hui , Wittwer Tobias , Dittrich‐Breiholz Oliver , Kracht Michael , Schmitz Michael Lienhard
Published: March 2009

The nuclear factor‐kappaB (NF‐κB) transcription factor system is a crucial component that controls several important biological functions, thus raising the need for mechanisms that ensure the correct termination of its activity. Here, we identify a new phosphorylation/ubiquitination switch in the NF‐κB network that controls the stability of the transactivating p65 subunit. Tumour necrosis factor‐induced phosphorylation of p65 at Ser468 allows binding of COMMD1 and cullin 2, components of a multimeric ubiquitin ligase complex mediating p65 ubiquitination. Mutation of p65 at Ser468 largely prevents p65 ubiquitination and proteasomal degradation. Inducible p65 elimination is restricted to a subset of NF‐κB target genes such as Icam1. Accordingly, chromatin immunoprecipitation experiments reveal the selective recruitment of Ser468‐phosphorylated p65 and COMMD1 to the Icam1 promoter. Phosphorylation of p65 at Ser468 leads to ubiquitin/proteasome‐dependent removal of chromatin‐bound p65, thus contributing to the selective termination of NF‐κB‐dependent gene expression.
Fork regression is an active helicase‐driven pathway in bacteriophage T4
Authors: Long David T , Kreuzer Kenneth N
Published: March 2009

Reactivation of stalled replication forks requires specialized mechanisms that can recognize the fork structure and promote downstream processing events. Fork regression has been implicated in several models of fork reactivation as a crucial processing step that supports repair. However, it has also been suggested that regressed forks represent pathological structures rather than physiological intermediates of repair. To investigate the biological role of fork regression in bacteriophage T4, we tested several mechanistic models of regression: strand exchange‐mediated extrusion, topology‐driven fork reversal and helicase‐mediated extrusion. Here, we report that UvsW, a T4 branch‐specific helicase, is necessary for the accumulation of regressed forks in vivo, and that UvsW‐catalysed regression is the dominant mechanism of origin‐fork processing that contributes to double‐strand end formation. We also show that UvsW resolves purified fork intermediates in vitro by fork regression. Regression is therefore part of an active, UvsW‐driven pathway of fork processing in bacteriophage T4.
Activation of RXR–PPAR heterodimers by organotin environmental endocrine disruptors
Authors: le Maire Albane , Grimaldi Marina , Roecklin Dominique , Dagnino Sonia , Vivat‐Hannah Valérie , Balaguer Patrick , Bourguet William
Published: March 2009

The nuclear receptor retinoid X receptor‐α (RXR‐α)–peroxisome proliferator‐activated receptor‐γ (PPAR‐γ) heterodimer was recently reported to have a crucial function in mediating the deleterious effects of organotin compounds, which are ubiquitous environmental contaminants. However, because organotins are unrelated to known RXR‐α and PPAR‐γ ligands, the mechanism by which these compounds bind to and activate the RXR‐α–PPAR‐γ heterodimer at nanomolar concentrations has remained elusive. Here, we show that tributyltin (TBT) activates all three RXR–PPAR‐α, ‐γ, ‐δ heterodimers, primarily through its interaction with RXR. In addition, the 1.9 Å resolution structure of the RXR‐α ligand‐binding domain in complex with TBT shows a covalent bond between the tin atom and residue Cys 432 of helix H11. This interaction largely accounts for the high binding affinity of TBT, which only partly occupies the RXR‐α ligand‐binding pocket. Our data allow an understanding of the binding and activation properties of the various organotins and suggest a mechanism by which these tin compounds could affect other nuclear receptor signalling pathways.
A novel function of granulocyte colony‐stimulating factor in mobilization of human hematopoietic progenitor cells
Authors: Zhang Yun , Cheng Guang , Yang Kun , Fan Rong , Xu Zhuwei , Chen Lihua , Li Qi , Yang Angang , Jin Boquan
Published: March 2009

Granulocyte colony‐stimulating factor (G‐CSF) is a common inducer of the release of hematopoietic progenitor cells (HPC) from the bone marrow into the peripheral blood. However, the molecular mechanisms underlying this action of G‐CSF have not been fully elucidated. Herein, we demonstrate that G‐CSF is a powerful chemotactic agent for human HPC other than modulating the adhesion molecules expressed on HPC or bone marrow stromal cells. G‐CSF directly chemoattracted HPC in transwell assay and this chemotaxis is time dependent and is specifically neutralized with antibodies that target its receptor. The number of cells transmigrated through the transwell toward G‐CSF stimuli was more than that of stromal cell‐derived factor‐1 at every concentration. G‐CSF induced a rapid, transient increase in F‐actin polymerization and the formation of focal contact rings in HPC, which are prerequisites for cell migration. The mechanism of G‐CSF‐induced chemotaxis appears to involve the phosphorylation of JAK1/STAT3 pathway. Collectively, these results provide evidence that G‐CSF promotes chemotactic functionality and suggests new avenues of investigation relevant to the mobilization of HPC.
The neurobiology of spontaneous actions and operant learning in Drosophila
Authors: Brembs Björn
Published: March 2009

Learning about the consequences of our actions (operant learning) is one of the major ways in which we learn to understand the world we live in. Despite our recent advances in the neurobiology of learning and memory, this “learning-by-doing” has largely withstood neurobiological scrutiny. This proposal aims to elucidate the molecular and neurobiological mechanisms of spontaneous behavioral choice and how decision-making is modulated by the consequences of such actions. This research will be done in a genetically amenable model system, the fruit fly Drosophila. We will use state-of-the-art genetic and behavioral techniques to identify the circuitry and molecular processes involved in generating spontaneous turning behavior and its modulation by operant learning. Operant learning is only one system among many which govern the organization of behavior. The long-term prospect of this research beyond this application is to understand how multiple memory systems interact to accomplish adaptive behavioral choice and decision-making.
Improved manometric setup for the accurate determination of supercritical carbon dioxide sorption
Authors: van Hemert Patrick , Bruining Hans , Rudolph E. Susanne J. , Wolf Karl-Heinz A. A. , Maas Jos G.
Published: March 2009

An improved version of the manometric apparatus and its procedures for measuring excess sorption of supercritical carbon dioxide are presented in detail with a comprehensive error analysis. An improved manometric apparatus is necessary for accurate excess sorption measurements with supercritical carbon dioxide due to the difficulties associated with the high sensitivity of density for pressure and temperature changes. The accuracy of the apparatus is validated by a duplicate measurement and a comparison with literature data. Excess sorption and desorption of CO2 on Filtrasorb 400 at 318.11 K up to 17 069 mole/m3 (15.474 MPa) were selected for this validation. The measured excess sorption maximums are 7.79±0.04 mole/kg at 2253 mole/m3 for the first sorption isotherm and 7.91±0.05 mole/kg at 2670 mole/m3 for its subsequent desorption isotherm. The sorption and desorption peaks of the duplicate experiment are 7.92±0.04 mole/kg at 2303 mole/m3 and 8.10±0.05 mole/kg at 2879 mole/m3, respectively. Both data sets show desorption data being higher than the sorption data of the same data set. The maximum discrepancy between the desorption and sorption isotherms of one data set is 0.15 mole/kg. The discrepancy between the two excess sorption isotherms is 0.12 mole/kg or less. The a priori error of the excess sorption measurements is between 0.02 and 0.06 mole/kg. The error due to He contamination is between 0.01 and 0.05 mole/kg. The difference between the a priori uncertainty and the observed maximum discrepancies is considered to be acceptable. The sorption isotherms show identical qualitative behavior as data in the literature. The quantitative behavior is similar but the peak height and the linear decrease in excess sorption at high gas densities are 10% higher. A plot of the excess sorption versus the density can be used to obtain the sorbed phase density and the specific micropore volume. These sorbed phase densities are in excellent agreement with the data in the literature. Furthermore, the excess sorption data scaled to this specific micropore volume in this work and in the literature collapse on a single curve when plotted versus gas density.
Origin of wavy weld boundary
Authors: Wei P. S. , Ting C. N. , Yeh J. S. , DebRoy T. , Chung F. K. , Yan G. H.
Published: March 2009

In conduction mode laser welding, the shape of the fusion boundary affects the solidification process, microstructure, and properties of the weld. Although significant progress has been made in the calculations of the shape and size of the fusion zone in recent decades, the conditions for the formation of the wavy fusion boundary are still not well understood. Here we examine the conditions for its formation in terms of important dimensionless numbers. In particular, the computed flow patterns, temperature fields, and molten pool shapes under the flat free surface are examined for various values of Marangoni, Prandtl, Peclet, and dimensionless heat input values. In the absence of electromagnetic force, it is shown that the wavy fusion boundary forms for specific ranges of Marangoni and Prandtl numbers.
Low noise dual free-layer magnetoresistive sensor with coupled resonance
Authors: Zhou Yuchen
Published: March 2009

Magnetic noise cancellation in trilayer magnetoresistive is studied with micromagnetic model. The noise reduction is related to the antiferromagnetic-type magnetostatic coupling between the two free layers in sub-100-nm sensor sizes. The coupled oscillation of the two free layers produces effective noise reduction in the total output signal and is able to enhance the signal-to-noise ratio. The noise reduction shows dependence on the relative angle between the two free layers. It is adversely affected by ferromagnetic-type coupling between the two free layers. It is sensitive to properties that affect the magnetostatic coupling strength.