bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of the welfare state on the number of young old persons
Authors: KOMP KATHRIN , VAN TILBURG THEO , VAN GROENOU MARJOLEIN BROESE
Published: April 2009

Many current discussions of welfare state reforms focus on the ‘young old’, a group now generally perceived as healthy people past retirement age without a legal responsibility for dependent persons in need of care. For the welfare state, they constitute a resource whose activities are hard to steer. This article focuses on the influence of the welfare state on the number of ‘young old’ people. It describes different ways in which the welfare state influences the number of young old persons, and investigates whether variations in the regulations for the ages of normal, early and late retirement are the prime cause. The paper also estimates the share of the young old among those aged 50–90 years in 10 European countries in 2004 using comparable survey data. These shares ranged between 36 and 49 per cent for men and between 35 and 52 per cent for women. High shares were found in continental European countries, and low shares in Scandinavian countries and the United Kingdom. The shares in southern European countries varied among the countries and by gender. To explain the variations in the share, country differences in retirement regulations proved helpful but insufficient. When the overall influence of the welfare state on the share of young old persons in the population was analysed, a country-characteristic pattern emerged.
Gender inequality in health among elderly people in a combined framework of socioeconomic position, family characteristics and social support
Authors: RUEDA SILVIA , ARTAZCOZ LUCÍA
Published: April 2009

This study analyses gender inequalities in health among elderly people in Catalonia (Spain) by adopting a conceptual framework that globally considers three dimensions of health determinants: socio-economic position, family characteristics and social support. Data came from the 2006Catalonian Health Survey. For the purposes of this study a sub-sample of people aged 65–85 years with no paid job was selected (1,113 men and 1,484 women). The health outcomes analysed were self-perceived health status, poor mental health status and long-standing limiting illness. Multiple logistic regression models separated by sex were fitted and a hierarchical model was fitted in three steps. Health status among elderly women was poorer than among the men for the three outcomes analysed. Whereas living with disabled people was positively related to the three health outcomes and confidant social support was negatively associated with all of them in both sexes, there were gender differences in other social determinants of health. Our results emphasise the importance of using an integrated approach for the analysis of health inequalities among elderly people, simultaneously considering socio-economic position, family characteristics and social support, as well as different health indicators, in order fully to understand the social determinants of the health status of older men and women.
Local star formation triggered by SN shocks in magnetized diffuse neutral clouds
Authors: Leão M. R. M. , de Gouveia Dal Pino E. M. , Falceta-Gonçalves D. , Melioli C. , Geraissate F. G.
Published: April 2009

Considering that the main source of turbulence in the ISM medium are the explosions of supernovae (SNe), we explore here the role of SN shock front interactions with clouds on the star formation triggering in presence and in absence of magnetic field.
Magnetic reconnection and energy release on the Sun and solar-like stars
Authors: van Driel-Gesztelyi Lidia
Published: April 2009

Magnetic reconnection is thought to play an important role in liberating free energy stored in stressed magnetic fields. The consequences vary from undetectable nanoflares to huge flares, which have signatures over a wide wavelength range, depending on e.g. magnetic topology, free energy content, total flux, and magnetic flux density of the structures involved. Events of small energy release, which are thought to be the most numerous, are one of the key factors in the existence of a hot corona in the Sun and solar-like stars. The majority of large flares are ejective, i.e. involve the expulsion of large quantities of mass and magnetic field from the star. Since magnetic reconnection requires small length-scales, which are well below the spatial resolution limits of even the solar observations, we cannot directly observe magnetic reconnection happening. However, there is a plethora of indirect evidences from X-rays to radio observations of magnetic reconnection. I discuss key observational signatures of flares on the Sun and solar-paradigm stellar flares and describe models emphasizing synergy between observations and theory.
Near-surface stellar magneto-convection: simulations for the Sun and a metal-poor solar analog
Authors: Steffen Matthias , Ludwig H.-G. , Steiner O.
Published: April 2009

We present 2D local box simulations of near-surface radiative magneto-convection with prescribed magnetic flux, carried out with the MHD version of the CO5BOLD code for the Sun and a solar-like star with a metal-poor chemical composition (metal abundances reduced by a factor 100, [M/H] = −2). The resulting magneto-hydrodynamical models can be used to study the influence of the metallicity on the properties of magnetized stellar atmospheres. A preliminary analysis indicates that the horizontal magnetic field component tends to be significantly stronger in the optically thin layers of metal-poor stellar atmospheres.
3D reconstruction of solar magnetoacoustic waves
Authors: Popescu Adrian Sabin
Published: April 2009

Using a new multi-wavelength technique applied on the solar corona SOHO/EIT images containing magnetoacoustic waves (EIT waves), we constrain the wave phase velocity and, as well, some β-model, height related considerations for the vertical extent of the wave, applied on the particular EIT wave triggered by the eruptive event from 15th of August, 2001.
Starspots: signatures of stellar magnetic activity
Authors: Strassmeier Klaus G.
Published: April 2009

Starspots, just as Sunspots, are among the most obvious tracers and signatures of stellar surface magnetic activity. Emphasized already several decades ago as the origin for the rotationally modulated brightness of cool late-type stars, it is just now that we start to trace individual surface features in great enough detail to understand their magnetic behavior and interaction. Starspots also became the most important “noise” for detecting extra-solar planets and could possibly be decisive when it comes to detect another Earth. Since this is not a review, and because indirect imaging techniques are covered in other papers in this volume, I focus in this paper on some specific detections of starspots and introduce four new facilities particularly suited for starspot research in the near future.
Search for the magnetic field of the O7.5 III star ξ Persei
Authors: Henrichs Huib F. , Schnerr R. S. , de Jong J. A. , Kaper L. , Donati J.-F. , Catala C.
Published: April 2009

Cyclical wind variability is an ubiquitous but as yet unexplained feature among OB stars. The O7.5 III(n)((f)) star ξ Persei is the brightest representative of this class on the Northern hemisphere. As its prominent cyclical wind properties vary on a rotational time scale (2 or 4 days) the star has been already for a long time a serious magnetic candidate. As the cause of this enigmatic behavior non-radial pulsations and/or a surface magnetic field are suggested. We present a preliminary report on our attempts to detect a magnetic field in this star with high-resolution measurements obtained with the spectropolarimeter Narval at TBL, France during 2 observing runs of 5 nights in 2006 and 5 nights in 2007. Only upper limits could be obtained, even with the longest possible exposure times. If the star hosts a magnetic field, its surface strength should be less than about 300 G. This would still be enough to disturb the stellar wind significantly. From our new data it seems that the amplitude of the known non-radial pulsations has changed within less than a year, which needs further investigation.
Magnetic observations of pulsating B and Be stars with ESPaDOnS and Narval
Authors: Silvester James , Neiner C. , Henrichs H. F. , Wade G. A. , Alecian E. , Petit V.
Published: April 2009

Discoveries of magnetic fields in pulsating B and Be stars have been claimed from low-resolution spectropolarimetric observations with FORS1 at VLT. We used the new generation of high-resolution spectropolarimeters, ESPaDOnS at CFHT and NARVAL at TBL, to check for the existence of these fields. We find that most of the claimed magnetic stars do not host a magnetic field. This work shows the importance of a critical analysis of FORS1 data when searching for weak magnetic fields in early-type stars and the advantage of using ESPaDOnS and NARVAL to study such type of stars.
Fossil fields in early stellar evolution
Authors: Arlt Rainer
Published: April 2009

Favored explanations for the presence of magnetic fields on CP stars and the presence of the solar tachocline below the convection zone both imply fossil magnetic fields in the radiative zones. The initial, convective evolution of magnetic fields in a proto-star is studied by numerical, global simulations. The computations are to be extended by a change of the convection zone depth on an evolutionary time-scale.
What do we really know about the magnetic fields of the Milky Way?
Authors: Wielebinski Richard
Published: April 2009

We have several methods of measuring magnetic fields in the Milky Way. We can study optical polarization, radio polarization, rotation measures of pulsars and extragalactic radio sources as well as include Zeeman results. Each of the above mentioned methods was at times used to make a model of the magnetic fields of the Milky Way. However one or two of the data sets by themselves cannot tell us the whole story. Any model of the magnetic fields must be able to fit all the observational results. At the present time a lot of progress has been made. We have increased our data bases in most of the observational areas. However a robust model of the magnetic field of the Milky Way has not yet emerged. We must possibly wait to the era of SKA.
Magnetic fields in the early Universe
Authors: Battaner Eduardo , Florido Estrella
Published: April 2009

There is increasing evidence that intense magnetic fields exist at large redshifts. They could arise after galaxy formation or in very early processes, such as inflation or cosmological phase transitions, or both. Early co-moving magnetic strengths in the range 1-10 nG could be present at recombination. The possibilities to detect them in future CMB experiments are discussed, mainly considering their impact in the anisotropy spectra as a result of Faraday rotation and Alfven waves. Magnetic fields this magnitude could also have a non-negligible influence in determining the filamentary large scale structure of the Universe.
MHD simulations of cool core clusters
Authors: Stasyszyn Frederico , Dolag Klaus
Published: April 2009

Using Smoothed Particle Magneto Hydrodynamics (Dolag & Stasyszyn), we study the effects of magnetic fields in galaxy clusters with the aim to infer their dynamical role within the cool core region. Therefore we we investigate the role of regularization as well as divergence cleaning schemes (Stasyszyn & Dolag 2009). We run cosmological simulations of a reference cluster in order to evaluate our various implementation in a realistic scenario. The preliminary results indicate that the final magnetic field profile in the simulations depends only on the amount of artificial dissipation, but not in the amount of numerical div(B) present in the different implementation. We also present first results from simulations which are including radiative cooling and star formation. Even at the this low resolution we find a strong additional amplification of the magnetic field within the cool core region indicating that magnetic pressure could become comparable to the thermal pressure in theses regimes.
MHD numerical simulations of Perseus A: formation of filaments and magnetic loops
Authors: Falceta-Gonçalves Diego , de Gouveia dal Pino E. M. , Gallagher J. , Lazarian A.
Published: April 2009

The Perseus Cluster (A426) is the brightest cluster of galaxies observed in X-rays in the sky and its giant central galaxy (NGC1275) hosts the extended double radio source 3C84. There is a spectacular H-alpha nebulosity surrounding NGC1275 with loops and filaments that are probably magnetized and extend over 100 kpc. The continuous blowing of bubbles leading to the propagation of shock fronts is also evident and more recently, outflow and infall velocities of several 1000 km/s have been detected associated to the surrounding filaments. We here present preliminary results of 2.5D MHD simulations of the Perseus cluster central region assuming that the production of the outflow structures and loops that arise from the surface of NGC1275 are due to turbulent injection triggered by recent star formation and SNe activity in the galaxy. This is in turn, probably induced by a continuous gas infall from the satellite galaxies around NGC1275. Our simulations which include both, the turbulent gas outflow and gas infall from the surroundings, have revealed a continuous formation of the observed features, like the filaments, the gigantic magnetic loops and weak shock fronts that propagate into the ICM medium with the observed velocities of 1000–5000 km/s. After 10 Myr, a nearly steady state is established between the outflow material emerging from the central galaxy and the inflow gas from the surrounds. The outflow activity seems to retard the cannibalism action of the central galaxy over the surrounding galaxies. This result may have important implications over the evolution of the whole cluster as it seems to indicate that the SF and SNe production that are induced by the cannibalism may help to decelerate the later due to turbulence and outflow production. These results also offer important clues to the hot halo formation in the center of the cluster and in the suppression of cooling flows.
Zeeman-Doppler imaging: old problems and new methods
Authors: Carroll Thorsten A. , Kopf Markus , Strassmeier Klaus G. , Ilyin Ilya
Published: April 2009

Zeeman-Doppler Imaging (ZDI) is a powerful inversion method to reconstruct stellar magnetic surface fields. The reconstruction process is usually solved by translating the inverse problem into a regularized least-square or optimization problem. In this contribution we will emphasize that ZDI is an inherent non-linear problem and the corresponding regularized optimization is, like many non-linear problems, potentially prone to local minima. We show how this problem will be exacerbated by using an inadequate forward model. To facilitate a more consistent full radiative transfer driven approach to ZDI we describe a two-stage strategy that consist of a principal component analysis (PCA) based line profile reconstruction and a fast approximate polarized radiative transfer method to synthesize local Stokes profiles. Moreover, we introduce a novel statistical inversion method based on artificial neural networks (ANN) which provide a fast calculation of a first guess model and allows to incorporate better physical constraints into the inversion process.
Effects of turbulence on magnetic reconnection: 3D numerical simulations
Authors: Otmianowska-Mazur Katarzyna , Kowal G. , Lazarian A. , Vishniac E.
Published: April 2009

Turbulent reconnection is studied by means of three dimensional (3D) compressible magnetohydrodynamical numerical calculations. The process of homogeneous turbulence is set up by adding three-dimensional solenoidal random forcing implemented in the spectral space at small wave numbers with no correlation between velocity and forcing. We apply the initial Harris current sheet configuration together with a density profile calculated from the numerical equilibrium of magnetic and gas pressures. We assume that there is no external driving of the reconnection. The reconnection develops as a result of the initial vector potential perturbation. We use open boundary conditions. Our main goal is to find the dependencies of reconnection rate on different properties of turbulence. The results of our simulations show that turbulence significantly affects the topology of magnetic field near the diffusion region. We present that the reconnection speed does not depend on the Reynolds numbers as well the magnetic diffusion. In addition, a fragmentation of current sheet decreases the disparity in inflow/outflow ratios. When we apply the large scale and more powerful turbulence the reconnection is faster.
Zur Bedeutung und Gestaltung von Autonomie und Fürsorge am Lebensende. Ergebnisse einer Befragung im Rahmen einer Vignettenstudie
Authors: Schnell Martin W. , Schulz Christian , Dunger Christine , Möller Mischa
Published: April 2009

In Gesellschaft und heilberuflicher Öffentlichkeit wird seit einiger Zeit über die Möglichkeiten einer für Patienten guten und durch Heilberufler professionell gestalteten Begleitung am Lebensende diskutiert. Welche Bedeutung in diesem Zusammenhang Autonomie (ausgedrückt etwa in Form von Patientenverfügungen) und Fürsorge für Experten (Pflegende, Ärzte, andere Experten) besitzen und wie diese Werte zugleich und miteinander gestaltet werden können, ist Gegenstand einer fragebogengestützten deskriptiven Vignettenstudie (n = 152). In der Bewertung der Fallgeschichten und in der damit verbundenen Beantwortung zusätzlicher Fragen äußern Pflegende und Ärzte, dass beide Werte – Autonomie und Fürsorge – gleichermaßen wichtig sind. Allerdings bleibt unklar und uneindeutig, was Autonomie und Fürsorge bedeuten und wie sie gemeinsam gestaltet und realisiert werden können. Sofern diese Uneindeutigkeit Ausdruck der Sache selbst ist, es also nie definitiv völlig eindeutig sein kann, was als Autonomie und Fürsorge in der Gestaltung der Begleitung am Lebensende zur Geltung kommen soll, wäre diese Sachlage von Gesetzgebungsinitiativen und in heilberuflichen Ausbildungsordnungen zu berücksichtigen.
Subjektives Wohlbefinden bei Morbus Parkinson
Authors: Pusswald Gisela , Fleck Martina , Haubenberger Dietrich , Auff Eduard , Weber Germain
Published: April 2009

Zusammenfassung. Ziel der Untersuchung/Fragestellung: In der vorliegenden Studie wird das subjektive Wohlbefinden nach Ryff erstmals an einer Stichprobe von Parkinsonpatienten untersucht. Es soll eruiert werden, durch welche Faktoren das Wohlbefinden beeinflusst wird. Aus diesem Grund werden entsprechend einer ressourcenorientierten Sichtweise auch die Depressivität, die Krankheitsverarbeitung und der Schweregrad der Erkrankung erhoben. Methode: Die Rekrutierung der Parkinsonstichprobe fand über die Medizinische Universität Wien, Neurologie statt. Ingesamt werden 51 Parkinsonpatienten (Durchschnittsalter: 67,7; Frauen: 43,1%; Männer: 56,9%) und 59 Personen ohne neurologische Erkrankung (Durchschnittsalter: 65,7; Frauen: 54,2%; Männer: 45,8%) mittels umfassender Fragebogenbatterie befragt: Ryff-Skala zu Erfassung des subjektiven Wohlbefindens, Freiburger Fragebogen zur Krankheitsverarbeitung (FKV) und Geriatrische Depressions Skala (GDS). Die Auswertung erfolgte mittels multipler Korrelationen, U-Tests und multivariaten Varianzanalysen. Ergebnisse: Parkinsonpatienten, charakterisiert durch eine stärkere depressive Tendenz und geringeren Einsatz eines aktiven Copingstils, weisen im Vergleich zu nicht-neurologisch Erkrankten ein geringeres subjektives Wohlbefinden auf. Auch Schweregrad und Dauer der Erkrankung zeigen sich mit dem Wohlbefinden assoziiert. Schlussfolgerung: Wie die Studienergebnisse deutlich machen, sei empfohlen neben der medizinischen Befunderhebung auch die psychologische Diagnostik in die Routineuntersuchung von Parkinsonpatienten zu implementieren. Denn nicht nur der Schweregrad der motorischen Symptome der neurologischen Erkrankung, auch die Entwicklung einer Depression sowie daraus resultierend die Art der Krankheitsbewältigung tragen erheblich zur Wohlbefindenseinschätzung bei. Nur durch ressourcenzentrierte psychologische Therapieansätze ist die Erhaltung der Lebensqualität mit zunehmender Schwere und Dauer der Parkinsonerkrankung möglich.
Implementierung, Akzeptanz und Informationsgehalt eines Ecological Momentary Assessment (EMA)-Ansatzes bei Patienten mit Panikstörung und Agoraphobie
Authors: Helbig Sylvia , Lang Thomas , Swendsen Joel , Hoyer Jürgen , Wittchen Hans-Ulrich
Published: April 2009

Zusammenfassung. Theoretischer Hintergrund: Ecological Momentary Assessment (EMA) ist eine Form des ambulanten Assessments, bei der wiederholt und alltagsnah Daten zu psychologischen Parametern gesammelt werden. Trotz messmethodischer Vorteile wird EMA bei klinisch-psychologischer Forschung vergleichsweise selten eingesetzt. Ziel: Evaluation der Implementierbarkeit, der Reaktivität und des Informationsgehalts von EMA im Vergleich zu Fragebogenverfahren. Methode: 21 Patienten mit Panikstörung und Agoraphobie wurden im Rahmen einer Studie zu Effekten einer Minimalintervention in der Wartezeit auf Kognitive Verhaltenstherapie randomisiert einer Versuchs- und einer Kontrollgruppe zugewiesen und vor sowie nach der Wartezeit mit störungsspezifischen Fragebögen sowie einer einwöchigen EMA-Erhebungsphase untersucht. Ergebnisse: Hohe Compliance-Raten (87%) sprachen für die Akzeptanz der Methode; allerdings gab es Hinweise auf Stichprobenselektionseffekte. Die Reaktivität des Verfahrens erwies sich als gering. EMA erlaubte jedoch differenziertere Aussagen sowohl in der Deskription der Symptomatik als auch im Vergleich der Untersuchungsgruppen. Schlussfolgerungen: EMA ist für klinische Untersuchungen empfehlenswert, insbesondere aufgrund seiner ökologischen Validität und des Informationsgewinns gegenüber Fragebogenverfahren.
Akute Belastungsreaktionen und neuroendokrine Stressachsenregulation nach Unfalltraumen
Authors: Badke Andreas , Domes Gregor , Schönenberg Michael
Published: April 2009

Zusammenfassung. Theoretischer Hintergrund: Einige Studienbefunde deuten darauf hin, dass eine Posttraumatische Belastungsstörung mit spezifischen Alterationen in der endokrinen Stressachsenaktivität assoziiert ist. Es wird angenommen, dass eine stark erhöhte Cortisolausschüttung in der traumatischen Akutphase zu einer Dysregulation des Systems und schließlich zu dauerhaft erniedrigter basaler Cortisolsekretion (Hypocortisolismus) führt. Fragestellung: Lassen sich Hinweise auf spezifische Verläufe in der diurnalen endokrinen Sekretion bei akut traumatisierten Personen in Abhängigkeit von der Symptomschwere finden? Methode: Eine Stichprobe von 50 akut verunfallten Patienten wurde nach der Schwere der Belastungssymptome in zwei Gruppen unterteilt. Die während der stationären Versorgung sowie 6 Wochen später dokumentierten Tagescortisolprofile wurden auf differenzielle Verläufe zwischen den Gruppen hin analysiert. Ergebnisse: Nach 6 Wochen zeigten die belasteten Patienten zwar leicht erhöhte Tagescortisolwerte, es konnten jedoch keine Anhaltspunkte für regelhaft spezifische Veränderungen in der Stressachsenaktivität zwischen den Gruppen gefunden werden. Diskussion: Auffälligkeiten in der Cortisolsekretion, als ereignisnahe Indikatoren/Prädiktoren einer posttraumatischen Belastungsreaktion, lassen sich in dieser Stichprobe nicht belegen.
Subevent structure of large earthquakes—A ground‐motion perspective
Authors: Beresnev Igor , Atkinson Gail
Published: April 2009

Our ability to predict ground motions from future earthquakes hinges on the accurate modeling of the radiation from the earthquake source. A successful approach to modeling earthquake radiation has been to represent faults as a series of discrete, independently‐rupturing subfaults, although their physical interpretation has remained largely unclear. Our simulation of ground motions from twenty‐six well‐recorded moderate‐to‐large earthquakes substantiates the hypothesis that large ruptures are made up of a sequence of smaller subevents. The size of a subevent follows a simple linear relationship with the size of the earthquake fault in an apparently deterministic manner. The strength of the high‐frequency radiation is controlled by the maximum slip velocity, which varies stochastically over a small range. Both the characteristic subevent size and the slip velocity appear to be region‐independent, indicating a remarkable uniformity in earthquake source properties. This observation helps to reduce the uncertainty in ground‐motion prediction by constraining its essential and previously ambiguous parameters.
Differential trends in tropical sea surface and atmospheric temperatures since 1979
Authors: Christy John R. , Parker David E. , Brown Simon J. , Macadam Ian , Stendel Martin , Norris William B.
Published: April 2009

A variety of measurements indicate that the rate of atmospheric warming in the tropics since 1979 is less than the observed warming of the sea surface. This result is further examined using the high quality buoys monitored by the Pacific Marine Environmental Laboratory in the Tropical Pacific Ocean. These buoys show cooling (most cases being statistically significant) of the air at 3m height relative to the sea at l m depth over 8 to 20‐year periods in the eastern region. A global surface temperature dataset which uses only near‐surface air temperature over both land and ocean, indicates less warming since 1979 than those using SSTs over the oceans, though large uncertainties remain with marine air temperatures.
A Quasi‐Biennial Oscillation in the equatorial Atlantic Ocean
Authors: Tseng Lishan , Mechoso Carlos R.
Published: April 2009

A quasi‐biennial oscillation with features characteristic of equatorial coupled modes is found in the equatorial Atlantic Ocean. The origins of the phenomenon are investigated by using a coupled atmosphere‐ocean general circulation model, in which the fully coupled domain is restricted to the Tropical Atlantic (20°S–30°N). The simulations capture a similar oscillation regardless of whether sea surface temperatures prescribed outside the coupled domain correspond to the observed or the climatology (i.e., lack year‐to‐year variability). It is concluded that the equatorial Atlantic hosts a quasi‐biennial oscillation generated by coupled atmosphere‐ocean interactions internal to the basin with little influence from remote events, even from El Niño/Southern Oscillation.
Thunder‐induced ground motions: 2. Site characterization
Authors: Lin Ting‐L. , Langston Charles A.
Published: April 2009

Thunder‐induced ground motion, near‐surface refraction, and Rayleigh wave dispersion measurements were used to constrain near‐surface velocity structure at an unconsolidated sediment site. We employed near‐surface seismic refraction measurements to first define ranges for site structure parameters. Air‐coupled and hammer‐generated Rayleigh wave dispersion curves were used to further constrain the site structure by a grid search technique. The acoustic‐to‐seismic coupling is modeled as an incident plane P wave in a fluid half‐space impinging into a solid layered half‐space. We found that the infrasound‐induced ground motions constrained substrate velocities and the average thickness and velocities of the near‐surface layer. The addition of higher‐frequency near‐surface Rayleigh waves produced tighter constraints on the near‐surface velocities. This suggests that natural or controlled airborne pressure sources can be used to investigate the near‐surface site structures for earthquake shaking hazard studies.
Climatology of columnar aerosol properties and the influence of synoptic conditions: First‐time results from the northeastern region of India
Authors: Gogoi Mukunda M. , Krishna Moorthy K. , Babu S. Suresh , Bhuyan Pradip K.
Published: April 2009

Six years of spectral aerosol optical depths (AODs), from the northeastern part of India (Dibrugarh), are used to evolve a climatology for this region. The results indicate that the seasonal mean AODs at 500 nm go as high as 0.45 ± 0.05 during premonsoon season (March to May), decrease gradually through the monsoon (June to September) to reach the lowest value of 0.19 ± 0.06 during the retreating‐monsoon season (October and November), and increase to 0.31 ± 0.04 in winter (December to February). The AOD spectra are generally flatter than those seen typically over continental sites of India (and elsewhere in the neighboring regions) with Ångström exponent α remaining below 1.0 during February through August, indicating a relatively low abundance of fine and accumulation mode aerosols. The columnar size distributions (CSD) retrieved from spectral AODs are, in general, bimodal with primary mode at ∼ 0.1 μm and secondary mode at ∼ 1.0 μm. High mass loading (∼309.5 ± 65.9 mg m−2) and effective radius (∼0.40 ± 0.09 μm) occur during premonsoon and are attributed to significant abundance of coarse (natural) aerosols. Cluster analysis of air mass back trajectories indicate significant transport of mineral dust from the arid regions of west Asia and northwest India across the Indo‐Gangetic plains and marine aerosols advected from the Bay of Bengal contributing largely to the coarse mode aerosols during this season. On the other hand, the peculiar topography combined with the local conditions and the widespread rainfall lead to a more pristine environment during retreating‐monsoon season with quite low AODs and columnar loading.
Development of a distributed biosphere hydrological model and its evaluation with the Southern Great Plains Experiments (SGP97 and SGP99)
Authors: Wang Lei , Koike Toshio , Yang Kun , Jackson Thomas J. , Bindlish Rajat , Yang Dawen
Published: April 2009

A distributed biosphere hydrological model, the so‐called water and energy budget‐based distributed hydrological model (WEB‐DHM), has been developed by fully coupling a biosphere scheme (SiB2) with a geomorphology‐based hydrological model (GBHM). SiB2 describes the transfer of turbulent fluxes (energy, water, and carbon fluxes) between the atmosphere and land surface for each model grid. The GBHM redistributes water moisture laterally through simulating both surface and subsurface runoff using grid‐hillslope discretization and then flow routing in the river network. The WEB‐DHM was calibrated and validated for the Little Washita Basin using field observations from Southern Great Plains Hydrology Experiments (SGP97 and SGP99). For the SGP97 period, the model was calibrated and it shows an ability to reproduce point‐scale energy fluxes (RMSE < 50 W m−2) as well as CO2 flux (RMSE = 4.6 μ mol m−2s−1). At basin scale, the WEB‐DHM can simulate a reasonable hydrograph (Nash = 0.956) and spatial soil moisture distribution with calibration of only a few soil hydraulic parameters for discharge. The model was then validated using SGP99 data sets and observed discharge. For the validation period, the model shows good performance in reproducing the soil surface temperature at 11 sites and the spatial distribution of surface soil moisture, as well as long‐term discharges (Nash = 0.715) in the hydroyear from 1 September 1998 to 31 August 1999 that covers both the annual largest flood peak of 1999 and the SGP99 period. To our knowledge, this work is the first to undertake the development and evaluation of a distributed biosphere hydrological model using such comprehensive field observations.
Dimming/brightening over the Iberian Peninsula: Trends in sunshine duration and cloud cover and their relations with atmospheric circulation
Authors: Sanchez‐Lorenzo Arturo , Calbó Josep , Brunetti Michele , Deser Clara
Published: April 2009

This study analyzes the spatial and temporal changes in sunshine duration (SunDu) and total cloud cover (TCC) over the Iberian Peninsula (IP) and four subregions during 1961–2004 using high‐quality, homogenized data sets. The analyses confirm that over most of the IP and in most seasons, SunDu and TCC variations are strongly negatively correlated, with absolute values ∼0.8–0.9. Somewhat weaker correlations (0.5–0.6) are found in the southern portion of the IP in summer. A large discrepancy between the SunDu and TCC records occurs from the 1960s until the early 1980s when the SunDu series shows a decrease that it is not associated with an increase in TCC. This negative trend or “dimming” is even more pronounced after removing the effects of TCC via linear regression. Since the early 1980s, the SunDu and TCC residual SunDu series exhibit an upward trend or “brightening.” In addition to the long‐term dimming and brightening, the volcanic eruptions of El Chichon and Mount Pinatubo are clearly evident in the TCC residual SunDu record. The TCC and SunDu records over the IP are well correlated with sea level pressure (SLP), with above normal TCC and below normal SunDu corresponding to below normal SLP locally in all seasons. The TCC and SunDu related SLP changes over the IP in winter and spring are part of a larger‐scale north‐south dipole pattern that extends over the entire Euro‐Atlantic sector. Other more regional atmospheric circulation patterns, identified from rotated principal component analysis, are also linked to TCC and SunDu variations over the IP. Finally and perhaps surprisingly, the TCC residual SunDu series exhibits a statistically significant relationship with a regional atmospheric circulation pattern during spring, summer, and autumn.
Systematics in the size structure of prairie pothole lakes through drought and deluge
Authors: Zhang Bo , Schwartz Franklin W. , Liu Ganming
Published: April 2009

This study examines the response of a complex lake‐wetland system to variations in climate. The focus is on the lakes and wetlands of the Prairie Coteau, which is part of the larger Prairie Pothole Region of the Central Plains of North America. Information on lake size was enumerated from satellite images and aerial photos and yielded power law relationships for different hydrological conditions. Of particular interest is a recent drought and deluge sequence, 1988–1992 and 1993–1998. Results showed that lake sizes followed well‐defined power laws that changed intra‐annually and interannually as a function of climate. The power laws for spring seasons in 1987, 1990, 1992, 1997, and 2002 have a relatively constant slope. However, slopes changed with time within each year. These lines produced from Landsat images and aerial photos describe a systematic variation in sizes for lakes ranging in area from 100 m2 to more than 30,000 m2. This tendency for lake size to follow a power law coupled with area measurement from aerial photos taken on 29 July 1939 provides a basis for reconstructing the distribution of pothole lakes in summer 1939, near the end of the Dust Bowl drought. The study shows that the areas of smaller lakes are profoundly affected seasonally by the spring snowmelt and evaporation. The areas of larger lakes are influenced more slowly by longer‐ term periods of drought and deluge.
Passive wick fluxmeters: Design considerations and field applications
Authors: Gee G. W. , Newman B. D. , Green S. R. , Meissner R. , Rupp H. , Zhang Z. F. , Keller J. M. , Waugh W. J. , van der Velde M. , Salazar J.
Published: April 2009

Optimization of water use in agriculture and quantification of percolation from landfills and watersheds require reliable estimates of vadose zone water fluxes. Current technology is limited primarily to lysimeters, which directly measure water flux but are expensive and may in some way disrupt flow, causing errors in the measured drainage. We report on design considerations and field tests of an alternative approach, passive wick fluxmeters, which use a control tube to minimize convergent or divergent flow. Design calculations with a quasi‐three‐dimensional model illustrate how convergence and divergence can be minimized for a range of soil and climatic conditions under steady state and transient fluxes using control tubes of varying heights. There exists a critical recharge rate for a given wick length, where the fluxmeter collection efficiency is 100% regardless of the height of the control tube. Otherwise, convergent or divergent flow will occur, especially when the control tube height is small. While divergence is eliminated in coarse soils using control tubes, it is reduced but not eliminated in finer soils, particularly for fluxes <100 mm/a. Passive wick fluxmeters were tested in soils ranging from nonvegetated semiarid settings in the United States to grasslands in Germany and rain‐fed crops in New Zealand and the South Pacific. Where side‐by‐side comparisons of drainage were made between passive wick fluxmeters and conventional lysimeters in the United States and Germany, agreement was very good. In semiarid settings, drainage was found to depend upon precipitation distribution, surface soil, topographic relief, and the type and amount of vegetation. In Washington State, United States, soil texture dominated all factors controlling drainage from test landfill covers. As expected, drainage was greatest (>60% annual precipitation) from gravel surfaces and least (no drainage) from silt loam soils. In Oregon and New Mexico, United States, and in New Zealand, drainage showed substantial spatial variability. The New Mexico tests were located in semiarid canyon bottom terraces, with flash flood prone locations having extremely high drainage/precipitation ratios. In the wettest environments, drainage was found to be closely linked to the rate and duration of precipitation events.
Using X‐ray micro‐tomography and pore‐scale modeling to quantify sediment mixing and fluid flow in a developing streambed
Authors: Chen Cheng , Packman Aaron I. , Gaillard Jean‐François
Published: April 2009

X‐ray micro‐tomography (XMT), image processing, and lattice Boltzmann (LB) methods were combined to observe sediment mixing, subsurface structure, and patterns of hydrogeological properties associated with bed sediment transport. Transport and mixing of sand and spherical glass beads were observed in a laboratory flume, beginning from a well‐defined layered initial condition. Cores were obtained from the streambed at four different times, and each core was scanned by XMT in order to assess the evolution of spatial patterns within the bed. Image analysis clearly revealed the propagation of a sediment mixing front that began at the bed surface. The image data were used as boundary conditions in 3D LB simulation of pore fluid flow, showing that sediment sorting produced strong vertical gradients in permeability near the streambed surface. This new methodological approach offers potential for greatly improved characterization of mixing and transport of fine sediments in a wide variety of aquatic systems.
Reconnection Hall current system observed in the magnetotail and in the ionosphere
Authors: Snekvik K. , Juusola L. , Østgaard N. , Amm O.
Published: April 2009

On 07 Sep 2001 around 21:40 UT, Cluster was located 19 RE downtail, and observed earthward fast flows and strong perturbations in the dawn‐dusk component of the magnetic field (BY). The perturbations corresponded to a sheet of tailward field aligned current close to the neutral sheet and another sheet of earthward field aligned current closer to the lobe. At Cluster footpoint, the ionospheric equivalent current density was monitored by the IMAGE magnetometer network. The observed equivalent current pattern is found to be consistent with a longitudinally extended current out of the ionosphere at 67° magnetic latitude and another sheet into the ionosphere 10 km further north. These observations provide evidence that the Hall current system generated in the ion diffusion region of a tail reconnection X‐line, can close in the ionosphere.
The Gene Ontology's Reference Genome Project: *A Unified Framework for Functional Annotation across Species
Authors: Gaudet Pascale ,   Reference Genome Group
Published: April 2009

Complete functional annotation of genomes is a powerful tool for researchers; however, such annotation is a time-consuming task limited by the availability of experimental data. The function of genes for which there is no experimental data can often be predicted via comparison to related, annotated sequences of known function. We describe here the Reference Genome project, an effort from the Gene Ontology (GO) Consortium to fully annotate twelve genomes to rigorous standards: human, plus eleven organisms that are important models in biomedical research, including mouse, fly, zebrafish, yeast and E. coli. To achieve this, we examine existing experimentally based annotations in a phylogenetic context in order to infer the function(s) of ancestral proteins and propagate these annotations to their descendants. This endeavor faces many difficult challenges, such as: the determination and provision of reference protein sets for each genome; the identification of gene families for curation; the application of consistent best practices for annotation; the development of methodologies for evaluating progress towards our goal; and the development of software tools to support this effort. Annotated genomes are greatly valuable to the research community and will provide the basis for using sequence similarity to annotate further genomes. An overview of the project as well as links to all resources described below can be found at "http://geneontology.org/GO.refgenome.shtml":http://geneontology.org/GO.refgenome.shtmlThis work is supported by NHGRI grant HG002273 (Gene Ontology Consortium) and NIGMS GM081084-01A1 (Phylogenetic tree building and annotation software development). Pascale Gaudet for the Reference Genome Group of the Gene Ontology Consortium. The Reference Genome project is overseen by Pascale Gaudet (dictyBase), Rex Chisholm (dictyBase) and includes these representatives from the curatorial staff: Tanya Berardini (TAIR), Emily Dimmer (GOA), Stacia R. Engel (SGD), Petra Fey (dictyBase), David P. Hill (MGI), Doug Howe (ZFIN), Jim Hu (EcoliWiki), Rachael Huntley (GOA), Varsha K. Khodiyar (UCL), Ranjana Kishore (WormBase), Donghui Li (TAIR), Ruth C. Lovering (UCL), Fiona McCarthy (AgBase), Li Ni (MGI), Victoria Petri (RGD), Deborah A. Siegel (EcoliWiki), Susan Tweedie (FlyBase), Kimberly Van Auken (WormBase), and Valerie Wood (GeneDB)—as well as the following computational staff representatives: Siddhartha Basu (dictyBase), Seth Carbon (BBOP), Mary Dolan (MGI), and Christopher J. Mungall (BBOP)—those establishing the protein families to be annotated: Kara Dolinski (PPOD), Michael S. Livstone (PPOD), and Paul Thomas (PANTHER)—and, the four PIs of the GO Consortium: Michael Ashburner (FlyBase), Judith A. Blake (MGI), J. Michael Cherry (SGD), and Suzanna E. Lewis (BBOP).
Xenopus and Zebrafish Annotation in the UniProt Knowledgebase (UniProtKB)
Authors: Foulger Rebecca , Consortium UniProt
Published: April 2009

The African clawed frog Xenopus laevis and the zebrafish Danio rerio have both proved to be good model organisms for studying early vertebrate cellular and developmental biology. More recently, the related western clawed frog Xenopus tropicalis has become a popular choice in the laboratory, since its shorter life style and diploid genome make it more amenable to genetic analysis. Ongoing sequencing of the X. tropicalis and D. rerio genomes, together with the growing number of EST/cDNA projects, is generating large amounts of sequence data and revealing many human developmental and disease genes that have counterparts in fish and frog.UniProtKB/Swiss-Prot curates Xenopus and zebrafish proteins with functional and sequence annotation from the literature and sequence analysis tools, using both controlled vocabularies (including GO terms) and free text. The tetraploid nature of the X. laevis and D. rerio genomes complicates annotation since the protein copies need to be identified and curated as separate UniProtKB/Swiss-Prot entries. The recent addition of Xenbase cross-references in Xenopus UniProtKB entries has been the result of cross-talk with Xenbase, and we continue to collaborate with ZFIN to ensure consistency between databases. UniProt is mainly supported by the NIH, European Commission FELICS, Swiss Federal Government, PATRIC BRC and NSF grants.
IMGT/GENE-DB: genomic reference sequences for human and mouse IG and TR genes and alleles
Authors: Bellahcene Fatena , Folch Géraldine , Jabado-Michaloud Joumana , Ginestoux Chantal , Duroux Patrice , Giudicelli Véronique , Lefranc Marie-Paule
Published: April 2009

The immunoglobulin (IG) and T cell receptor (TR) major loci span about 6 Megabases (Mb) of the human genome on chromosomes 2, 7, 14 and 22, and 9 Mb in mouse on chromosomes 6, 12, 13, 14 and 16. There are seven major loci: three IG loci (IGH, IGK, IGL) and four TR loci (TRA, TRB, TRG, TRD), with a distinct repartition of the variable (V), diversity (D), joining (J) and constant (C) genes. The human genome comprises a total number of 608-665 IG and TR genes (371-422 IG and 237-243 TR), depending on the haplotypes, per haploid genome ^1, 2^ of which 531-588 genes are located in the major loci (distributed in 369-418 V, 32 D, 105-109 J and 25-29 C genes). There are also 77 orphons (68 IG and 9 TR) including two processed IG genes, outside the major loci. The number of functional IG and TR genes is 308-356 (136-171 IG and 172-185 TR) per haploid genome. The mouse genome comprises an approximate number of 876 IG and TR genes (624 IG and 252 TR). All these genomic data are available in the IMGT® gene database, IMGT/GENE-DB ^3^. The major contribution of IMGT/GENE-DB has been to establish, for the first time, a standardized nomenclature of the IG and TR genes and alleles of humans and other vertebrates. In April 2009, IMGT/GENE-DB manages 1999 genes and 3026 alleles. [1] Lefranc M.-P. and Lefranc G., The Immunoglobulin FactsBook, Academic Press, London, 458 pages (2001).[2] Lefranc M.-P. and Lefranc G., The T cell receptor FactsBook, Academic Press, London, 398 pages (2001).[3] Giudicelli V. et al. Nucleic Acids Res., 33, D256-261 (2005).
SGN Database: From QTLs to Genomes
Authors: Tecle Isaak , Menda Naama , Buels Robert , Mueller Lukas
Published: April 2009

Quantitative trait loci (QTL) analysis is used to dissect the genetic basis underlying polygenic traits. Several public databases have been storing and making QTL data available to research communities. To our knowledge, current QTL databases rely on manual curation where curators read literature and extract relevant QTL information to store in databases. Evidently, this approach is expensive in terms of expert manpower and time use and limits the type of data that can be curated. At the Solanaceae Genomics Network (SGN) ("http://sgn.cornell.edu":http://sgn.cornell.edu), we have developed a database to store raw phenotype and genotype data from QTL studies, perform, on the fly, QTL analysis using R/QTL statistical software ("http://www.rqtl.org":http://www.rqtl.org) and visualize QTLs on a genetic map. Users can identify peak, and flanking markers for QTLs of traits of interest. The QTL database is integrated with other SGN databases (eg. Marker, BACs, and Unigenes), and analysis tools such as the Comparative Map Viewer. Using the comparative map viewer, users can compare chromosome with QTL regions to genetic maps of interest from the same or different Solanaceae species. As the tomato genome sequencing advances, users can also identify corresponding BAC sequences or locations on the tomato physical map, which can be suggestive of candidate genes for a trait of interest.Furthermore at SGN, images, quantitative phenotype and genotype data, publications, genetic maps generated by QTL studies are displayed and available for download. Currently, data from three F2 and two backcross population QTL studies on fruit morphology traits (18 – 46 traits per population) is available at the SGN website for viewing at population, accession, and trait levels. Traits are described using ontology terms. Phenotype data is presented in tabular and graphical formats such as frequency distributions with basic descriptive statistics. Mapping data showing location of parental alleles on individual accession genetic maps is also available.SGN is a public database hosted at Boyce Thomson Institute, Cornell University, and funded by USDA CSREES and NSF.