bluuebunny/crossref_metadata_2025 huggingface dataset:
The grammar of graphics
Authors: Wilkinson Leland
Published: October 2010

The grammar of graphics (GoG) denotes a system with seven classes embedded in a data flow. This data flow specifies a strict order in which data are transformed from a raw dataset to a statistical graphic. Each class contains multiple methods, each of which is a function executed at the step in the data flow corresponding to that class. The classes are orthogonal, in the sense that the product set of all classes (every possible sequence of class methods) defines a space of graphics which is meaningful at every point. The meaning of a statistical graphic is thus determined by the mapping produced by the function chain linking data and graphic. WIREs Comp Stat 2010 2 673–677 DOI: 10.1002/wics.118

This article is categorized under:

Statistical and Graphical Methods of Data Analysis > Statistical Graphics and Visualization
The use of long acting subcutaneous levonorgestrel (LNG) gel depot as an effective contraceptive option for cotton‐top tamarins (Saguinus oedipus)
Authors: Wheaton C.J. , Savage A. , Shukla A. , Neiffer D. , Qu W. , Sun Y. , Lasley B.L.
Published: October 2010

Cotton‐top tamarins (Saguinus oedipus) are a critically endangered species that have been bred successfully in captivity for many years. For two decades, the Cotton‐top Tamarin SSP© has been challenged with a high rate of reproduction combined with a history of contraceptive failures and nonrecommended births using the current Depo Provera® (medroxyprogesterone acetate) injection followed by MGA (melengestrol acetate) implant contraception combination. To address these issues we have developed and tested the use of levonorgestrel (LNG) as an effective contraception option for cotton‐top tamarins. LNG was delivered in an injectable, gel matrix consisting of polylactic‐co‐glycolic acid, triethyl citrate and N‐methylpyrrolidone. This gel matrix forms a biodegradable depot at the subcutaneous injection site providing slow release of the active ingredient. Gel matrix composition and LNG concentration were adjusted in four gel formulations to maximize the duration of contraceptive efficacy while minimizing immediate post‐injection increases in fecal LNG concentration. LNG treatment (68.44±8.61 mg/kg) successfully eliminated ovarian cycles (fecal pregnanediol‐3‐glucuronide (PdG) and estrone conjugates (E1C)) for 198.8±70.3 days (formulation four; range 19–50 weeks). It was demonstrated that subcutaneous LNG depot injection was an effective, reversible contraceptive option for the management of cotton‐top tamarins in captivity. Zoo Biol 30:498–522, 2011. © 2010 Wiley Periodicals, Inc.
Protein kinase Cμ mediates adenosine‐stimulated steroidogenesis in primary rat adrenal cells
Authors: Chen Yung-Chia , Chen Ying , Huang Shih-Horng , Wang Seu-Mei
Published: October 2010

Adenosine (Ado), an endogenous nucleoside, can stimulate corticosterone synthesis in adrenal cells via the A2A/A2B adenosine receptors (ARs). This study evaluated the contribution of protein kinase C (PKC) isoforms in Ado‐induced steroidogenesis. The PKC inhibitor calphostin c blocked Ado‐induced steroidogenesis, the mitogen‐activated protein kinase (MEK)‐extracellular signal‐related regulated kinase (ERK)‐cyclic AMP responsive element‐binding protein cascade, and the mRNA expression of steroidogenic acute regulatory protein and CYP11B1. Further analyses revealed that PKCμ was indeed activated by Ado. Moreover, downregulation of PKCμ by small interfering RNA (siRNA) inhibited Ado‐stimulated steroidogenesis and ERK phosphorylation. Finally, inhibition of either A2AAR or A2BAR led to the suppression of PKCμ phosphorylation. Together, these findings suggest that A2AR‐PKCμ‐MEK signaling mediates Ado‐stimulated adrenal steroidogenesis.
Studying base pair open–close kinetics of tRNALeu by TROSY‐based proton exchange NMR spectroscopy
Authors: Hao Zhan-Xi , Tan Min , Liu Chang-Dong , Feng Rui , Wang En-Duo , Zhu Guang
Published: October 2010

The millisecond conformational flexibility is functionally important for nucleic acids and can be studied through probing the base pair open–close kinetics by proton exchange nuclear magnetic resonance (NMR) spectroscopy. Here, the traditional imino proton exchange NMR experiments were modified with transverse relaxation optimized spectroscopy and were applied to accurately measure imino proton exchange rates of all base pairs in Escherichia coli tRNALeu (CAG), and their dependence on magnesium ion concentration. Finally, we correlated millisecond conformational flexibility with aminoacylation of tRNALeu and proposed that the flexibility of the acceptor stem and the core region might contribute to aminoacylation of tRNALeu.
MALAT‐1 enhances cell motility of lung adenocarcinoma cells by influencing the expression of motility‐related genes
Authors: Tano Keiko , Mizuno Rie , Okada Tomoko , Rakwal Randeep , Shibato Junko , Masuo Yoshinori , Ijiri Kenichi , Akimitsu Nobuyoshi
Published: October 2010

MALAT‐1, a long non‐coding RNA, is associated with metastasis, but its role in the metastatic process remains unknown. Here, we show that short‐interfering RNA‐mediated MALAT‐1 silencing impaired in vitro cell motility of lung cancer cells and influenced the expression of numerous genes. In these genes, knockdown of any one of CTHRC1, CCT4, HMMR, or ROD1 clearly inhibited cell migration. In MALAT‐1 knockdown cells, pre‐mRNA levels were decreased in some but not all genes. Thus, our findings suggest that MALAT‐1 is a novel class of non‐coding RNA that promotes cell motility through transcriptional and post‐transcriptional regulation of motility related gene expression.
Developmentally regulated expression of Sox9 and microRNAs 124,128 and 23 in neuroepithelial stem cells in the developing spinal cord
Authors: Farrell Barbara C. , Power Emmet M. , Dermott Kieran W. Mc
Published: October 2010

Central nervous system development is a complex process involving many interacting factors. MicroRNAs have recently been identified as playing key intrinsic roles in development however few of their specific targets have been identified in vivo. The transcription factor Sox9 has recently been identified as a target of miR‐124 in the adult mouse sub‐ventricular zone. Here we investigate the expression of the microRNAs miR‐124, miR‐128 and miR‐23 and that of transcription factor Sox9, in neuroepithelial stem cells in the developing spinal cord. Furthermore we investigate if neurogenesis in embryonic neuroepithelial cells in the spinal cord might also be regulated by the interaction of Sox9 and miR‐124. We provide evidence of the spatial and temporal regulation of miR‐124, miR‐128, miR‐23 and Sox9, and taken together with recent findings we provide evidence that Sox9 may also be target of miR‐124 in developing spinal cord neuroepithelial cells.
Zur Verzahnung von Jugendhilfe, Gesundheitssystem und Eingliederungshilfe - Ergebnisse des 13. Kinder- und Jugendberichts
Authors: Permien Hanna
Published: October 2010

Einleitung

Der 13. Kinder- und Jugendbericht befasste sich mit der gesundheitlichen Situation von jungen Menschen und den Möglichkeiten der Kinder- und Jugendhilfe im Bereich von Gesundheitsförderung und Prävention. Gerade im psychosozialen Bereich können die sozialpädagogischen Ansätze die Gesundheit der Mädchen und Jungen fördern, erhalten sowie sie und ihre Familien motivieren, Gesundheitsrisiken zu vermeiden. Allerdings fehlt es oft an flächendeckenden und kontinuierlichen Kooperationen zwischen den verschiedenen Arbeitsfeldern (Frühe Hilfen, Familienbildung, Kindertagesbetreuung, Jugendarbeit, Erziehungshilfen) und an ausreichenden Unterstützungsmaßnahmen, damit gerade auch benachteiligte Kinder und Jugendliche unkompliziert und gezielt notwendige Hilfen erhalten.
Aktion ,,Ich geh zur U! Und Du?‘‘ – Erfahrungen auf kommunaler Ebene
Authors: Wolfram Nicole
Published: October 2010

Einleitung

Die Früherkennungsuntersuchungen im Kindesalter erheben regelmäßig und standardisiert die körperliche, geistige und soziale Entwicklung des Kindes. Sie stellen ein wertvolles Instrument zur Steuerung der kindlichen Entwicklung dar. Um die Akzeptanz auf Seiten der Eltern, insbesondere aus bildungsfernen und sozial schwachen Schichten zu erhöhen, wurde im Jahr 2004 von der Bundeszentrale für gesundheitliche Aufklärung die Aktion „Ich geh’ zur U! Und Du?“ ins Leben gerufen. Im Beitrag wird die Umsetzung und Adaption des bundesweiten Ansatzes auf kommunaler Ebene dargelegt.
PALME – ein Präventives Elterntraining für alleinerziehende Mütter geleitet von ErzieherInnen
Authors: Franz Matthias , Weihrauch Lonja , Schäfer Ralf
Published: October 2010

Einleitung

Auf bindungstheoretischer Grundlage wurde ein emotionszentriertes präventives Elterntraining für allein erziehende Mütter mit Kindern im Vorschulalter entwickelt. Die Wirksamkeit des Trainings wurde in einer randomisierten, kontrollierten Studie untersucht. Es zeigten sich signifikante Gruppe x Messzeitpunkt-Interaktionseffekte zugunsten der Interventionsgruppe. Angesichts des Nutzens und der geringen Kosten könnte dieses Elterntraining z.B. in kommunalen Settings angeboten werden.
Wie wirkt sich täglicher Schulsport auf den juvenilen Medienkonsum aus?
Authors: Liersch Sebastian , Bisson Susanne , Sterdt Elena , Henze Vicky , Krauth Christian , Räbl Markus , Walter Ulla
Published: October 2010

Einleitung

Die Interventionsmaßnahme „fit für pisa“ ergänzt während der gesamten 4-jährigen Grundschulzeit die obligatorischen zwei Schulstunden Sport/Woche durch drei weitere Sportstunden an fünf Grundschulen in Göttingen. Die von 2007-2010 BMBF-geförderte Evaluationsstudie soll Aufschluss darüber geben, inwieweit sich ein quantitativ gesteigerter und qualitativ verbesserter Sportunterricht auf Gesundheit und Bewegungsverhalten von Schülern nachhaltig auswirkt.
Worship and threshold obligations
Authors: GWIAZDA JEREMY
Published: October 2010

In this reply to Tim Bayne and Yujin Nagasawa, I defend the possibility of a maximal-excellence account of the grounding of the obligation to worship God. I do not offer my own account of the obligation to worship God; rather I argue that the major criticism (that is raised against maximal-excellence accounts) fails. Thus maximal-excellence can ground an obligation to worship God.
ON RATE OPTIMALITY FOR ILL-POSED INVERSE PROBLEMS IN ECONOMETRICS
Authors: Chen Xiaohong , Reiss Markus
Published: October 2010

In this paper we clarify the relations between the existing sets of regularity conditions for convergence rates of nonparametric indirect regression (NPIR) and nonparametric instrumental variables (NPIV) regression models. We establish minimax risk lower bounds in mean integrated squared error loss for the NPIR and NPIV models under two basic regularity conditions: the approximation number and the link condition. We show that both a simple projection estimator for the NPIR model and a sieve minimum distance estimator for the NPIV model can achieve the minimax risk lower bounds and are rate optimal uniformly over a large class of structure functions, allowing for mildly ill-posed and severely ill-posed cases.
CONVERGENCE RATES FOR ILL-POSED INVERSE PROBLEMS WITH AN UNKNOWN OPERATOR
Authors: Johannes Jan , Van Bellegem Sébastien , Vanhems Anne
Published: October 2010

This paper studies the estimation of a nonparametric functionϕfrom the inverse problemr=Tϕgiven estimates of the functionrand of the linear transformT. We show that rates of convergence of the estimator are driven by two types of assumptions expressed in a single Hilbert scale. The two assumptions quantify the prior regularity ofϕand the prior link existing betweenTand the Hilbert scale. The approach provides a unified framework that allows us to compare various sets of structural assumptions found in the econometric literature. Moreover, general upper bounds are also derived for the risk of the estimator of the structural functionϕas well as that of its derivatives. It is shown that the bounds cover and extend known results given in the literature. Two important applications are also studied. The first is the blind nonparametric deconvolution on the real line, and the second is the estimation of the derivatives of the nonparametric instrumental regression function via an iterative Tikhonov regularization scheme.
Host preference and host limitation of vascular epiphytes in a tropical dry forest of central Mexico
Authors: Vergara-Torres Carmen Agglael , Pacheco-Álvarez Mary Carmen , Flores-Palacios Alejandro
Published: October 2010

It has been suggested that vascular epiphyte composition and abundance may be influenced by forest host composition. We studied the epiphyte species distribution among host species of a tropical dry forest in Mexico. All the epiphyte stands supported by woody plants (dbh > 3 cm) of ten forest plots (0.1 ha each) were counted. We measured the dbh of all the hosts, noted their bark characteristics (texture and peeling behaviour), and measured the bark thickness of the most abundant host species. Epiphyte distribution was biased toward a high concentration of epiphytes in three host species and a lower abundance of epiphytes on five host species. This was consistent among epiphyte taxa and host species, allowing us to classify hosts as preferred (with more epiphyte stands than expected by chance) and limiting species (with fewer epiphyte stands than expected by chance), at a community level. Host quality did not relate to mean phorophyte size (measured as basal area) or to bark characteristics (peeling behaviour, thickness and texture) between species. For some epiphyte taxa, the observed distribution indicated that the forest contained preferred and limiting host species mainly. Our data suggest that the epiphyte species in the forest studied could be host limited. We concluded that neither host size nor obvious bark characteristics can be used to predict epiphyte distribution and that further research is necessary.
Rain-forest canopy-connectivity and habitat selection by a small neotropical primate, Geoffroy's tamarin (Saguinus geoffroyi)
Authors: Madden D. , Garber P. A. , Madden S. L. , Snyder C. A.
Published: October 2010

Wild populations of a small neotropical primate, Geoffroy's tamarin (Saguinus geoffroyi), were studied through 30-s instantaneous observational sampling to identify different canopy habitats used by this tamarin. Tree and shrub canopies were sampled in randomly selected plots and in nearby plots that tamarins were observed to use in the forests of Agua Clara, Panama (28 d, 59 100-m2plots, 32.25 h of tamarin observations, 27 tamarins in total), and in the nearby forests of Barro Colorado Island (49 d, 29 100-m2plots, 29.6 h of tamarin observations, 14 tamarins in total). Light penetration through the canopy, ambient temperature and humidity, presence of other primates, stem diameters, plant life-forms, distribution of woody flora, abundance of fleshy fruits and arthropods typically consumed by tamarins and abundance of thorny vegetation and biting arthropods in plots used by tamarins were compared with control plots. Habitats used by tamarins had significantly shorter distances between adjacent tree canopies and between canopies and the ground. There was a random distribution of large insects and fleshy fruits that tamarins are known to eat. Habitat selection by tamarins may not be influenced by spiny vegetation, but tamarins may avoid areas with abundant hooked thorns and blood-sucking arthropods. Mobility along runways in various tiers of a rain-forest canopy may be of primary importance, with local abundance of food being a secondary consideration in habitat selection by this small primate.
Dichotomy and infinite combinatorics: the theorems of Steinhaus and Ostrowski
Authors: BINGHAM N. H. , OSTASZEWSKI A. J.
Published: October 2010

We define combinatorial principles which unify and extend the classical results of Steinhaus and Piccard on the existence of interior points in the distance set. Thus the measure and category versions are derived from one topological theorem on interior points applied to the usual topology and the density topology on the line. Likewise we unify the subgroup theorem by reference to a Ramsey property. A combinatorial form of Ostrowski's theorem (that a bounded additive function is linear) permits the deduction of both the measure and category automatic continuity theorems for additive functions.
A non-negative tensor factorization model for selectional preference induction
Authors: VAN DE CRUYS TIM
Published: October 2010

The distributional similarity methods have proven to be a valuable tool for the induction of semantic similarity. Until now, most algorithms use two-way co-occurrence data to compute the meaning of words. Co-occurrence frequencies, however, need not be pairwise. One can easily imagine situations where it is desirable to investigate co-occurrence frequencies of three modes and beyond. This paper will investigate tensor factorization methods to build a model of three-way co-occurrences. The approach is applied to the problem of selectional preference induction, and automatically evaluated in a pseudo-disambiguation task. The results show that tensor factorization, and non-negative tensor factorization in particular, is a promising tool for Natural Language Processing (nlp).
Net community production and gross primary production rates in the western equatorial Pacific
Authors: Stanley Rachel H. R. , Kirkpatrick John B. , Cassar Nicolas , Barnett Bruce A. , Bender Michael L.
Published: October 2010

Net community production (NCP) and gross primary production (GPP) are two key metrics for quantifying the biological carbon cycle. In this study, we present a detailed characterization of NCP and GPP in the western equatorial Pacific during August and September 2006. We use continuous measurements of dissolved gases (O2 and Ar) in the surface water in order to quantify NCP at subkilometer scale resolution. We constrain GPP in discrete samples using the triple isotopic composition of O2. We find the average NCP in the western equatorial Pacific is 5.9 ± 0.9 mmol O2 m−2 d−1 (equivalent to 1.5 ± 0.2 mol C m−2 yr−1 with error estimates reflecting 1σ confidence levels) and the average GPP is 121 ± 34 mmol O2 m−2 d−1 (equivalent to 32 ± 9 mol C m−2 yr−1). The measurements reveal significant spatial variability on length scales as small as 50 km. The NCP/GPP ratio is 5.7% ± 1.8%. We also present results for NCP and GPP in the coastal area off Papua New Guinea and for GPP in the central Pacific along the equator.
Temporal evolution of the water mass properties during the Eastern Mediterranean transient (EMT) in the Aegean Sea
Authors: Sayın Erdem , Beşiktepe Şükrü T.
Published: October 2010

We present time series of temperature and salinity of the Aegean Sea using the data sets for the period from 1991 to 1996 from 15 oceanographic cruises to depict the temporal variability of the water masses of the Aegean Sea. This period covers an interesting large‐scale change in the thermohaline circulation in the Eastern Mediterranean and the Aegean Sea. This change is known as the Eastern Mediterranean transient (EMT) and was first described during early 1990s. Our analysis reveals that very dense water formation in the Central Aegean Sea is partially due to the anomalous decrease in winter atmospheric temperature although this alone cannot completely account for the formation of the dense water. A synchronous increase in surface salinity accompanied by low temperature values in the winter months is also necessary for the EMT event to occur.
Mapping the Agulhas Current from space: An assessment of ASAR surface current velocities
Authors: Krug M. , Mouche A. , Collard F. , Johannessen J. A. , Chapron B.
Published: October 2010

Over 2 years of surface current information collected in the Agulhas Current region and derived from the Doppler centroid anomalies of Envisat's advanced synthetic aperture radar (ASAR) are examined. The sources of errors and potential use of ASAR surface current velocities for oceanographic research are assessed. ASAR surface current velocities are compared to surface drifter data and merged altimetry observations. Maps of sea surface temperature are used to establish the ASAR's capacity to capture the synoptic circulation. Discrepancies between observed and predicted ASAR velocities result predominantly from inadequate wind corrections combined with radar incidence angles below 30°. Occasionally observed wind‐induced outliers cause a bias in the estimated ASAR velocities but do not affect the ability of the ASAR to systematically image regions of strong surface current flow and shear. Time‐averaged maps of ASAR‐derived surface current velocity seem able to accurately capture the position as well as the intensity of the Agulhas Current. The ability of the ASAR to pick up the smaller features of the circulation along the shelf break also shows that variability along the Agulhas Bank is of the same order of magnitude as that observed in the Agulhas retroflection. ASAR surface current velocities offer a very good complement to altimetry in regions where the mean dynamic topography is poorly resolved. The quasi‐synoptic nature of ASAR acquisitions combined with the relatively high resolution of ASAR surface current velocities also make it attractive for studies of submesoscale processes and western boundary current dynamics.
The Effect of a River Delta and Coastal Roughness Variation on a Landfalling Tropical Cyclone
Authors: Au‐Yeung Andie Y. M. , Chan Johnny C. L.
Published: October 2010

Numerical simulations on an f plane are performed using the Weather Research Forecasting (WRF) model to study how the presence of a river delta and variations in coastal roughness might affect the motion and the structure of a tropical cyclone (TC) near landfall. In each delta experiment, an idealized triangular‐shaped delta, pointing to the west with length 150 km and a river mouth size of 100 km, is inserted along the coastline. The surface roughness and the moisture availability of the delta vary among the delta experiments, and the surface properties are uniform in the rest of the land area. In another set of experiments, where there is no delta, the roughness of a whole land area has different values along the north–south oriented coast. Results suggest that the TC in the control experiment (CTRL, with no delta or roughness variation along the coast) is weaker than all the delta cases during a certain period before landfall. Moisture supply from the delta appears to have an effect on sustaining the approaching TC, despite the relatively small scale of the delta. Tracks of the TCs in the roughness variation experiments deviate from that of the CTRL. The roughness variation along the coast apparently affects the convergence patterns—higher roughness induces stronger convergence and hence increases the vertical advection term in the potential vorticity tendency distribution over the rougher area. Hence, a TC tends to move toward a region with higher roughness.
Rainwater path in warm clouds derived from combined visible/near‐infrared and microwave satellite observations
Authors: Bennartz Ralf , Watts Philip , Meirink Jan Fokke , Roebeling Rob
Published: October 2010

The effects of warm rain on optical properties of clouds in the visible/near‐infrared (VNIR) and passive microwave (PMW) are studied using a simple conceptual cloud model. It is shown that the combined use of PMW and VNIR observations allows for the detection of precipitation and the derivation of rainwater path utilizing the different physical information content of the two observation types. Various potential error sources are studied and one month of combined geostationary visible/near infrared and Advanced Microwave Scanning Radiometer‐EOS (AMSR‐E) passive microwave observations off the coast of South Africa are evaluated using the proposed approach. Comparisons with CloudSat radar reflectivities are used for an independent assessment. A gradual increase in retrieved rainwater path with column maximum radar reflectivity is found for reflectivity values larger than −10 dBz. For monthly mean values at 1 × 1 degree resolution, rainwater path is correlated with in‐cloud liquid water path (R2 = 0.50). The strongest correlation (R2 = 0.69) exists between rainwater path and the inverse of cloud droplet number concentration (N). This finding is consistent with other studies supporting a 1/N dependency of precipitation intensity on cloud droplet number concentration in warm clouds.
Examination of gully sites on Mars with the shallow radar
Authors: Nunes Daniel Cahn , Smrekar Suzanne E. , Safaeinili Ali , Holt John , Phillips Roger J. , Seu Roberto , Campbell Bruce
Published: October 2010

Martian gullies, found on steep slopes along broad mid‐latitudinal bands, have morphologies resembling those of water‐carved gullies on Earth and have been dated to <10 Ma. As such, one of the leading hypotheses, though not unique, is that martian gullies formed by the flow of liquid water in the very recent geologic past. Since the permittivity of liquid water is about one order of magnitude higher than that of most silicates, it is plausible that subsurface geologic interfaces involving liquid water may be detected via ground penetrating radar. We have surveyed a substantive portion of the martian gully population with data from the Shallow Radar (SHARAD) instrument, on board the Mars Reconnaissance Orbiter (MRO), in search of strong subsurface radar reflections indicative of the presence of liquid water reservoirs, which would serve as sources to the flows occurring within gullies. No such reflections are found at most of the locations surveyed, suggesting that either liquid water is not likely present in detectable amounts or that the shallow martian subsurface is unusually electrically conductive (i.e., lossy) at all of the locations examined. Strong subsurface reflections occur in the vicinity of gullies at two locations in the northern lowlands: Arcadia and southeastern Utopia Planitiae. In both cases, the reflectors occur at a range in depth of 45 to 90 m, considering a range in permittivity of 3 to 10, and −20 to −30 dB weaker than the surface reflection. In the case or Arcadia, the reflector corresponds to the eastern edge of Plaut et al.'s (2009) extensive radar subsurface unit; in both Arcadia and Utopia we interpret the reflectors as ground ice. Though our results offer a general assessment of the gully population, SHARAD is continuing its survey of gully rich locations.
Past and future water conflicts in the Upper Klamath Basin: An economic appraisal
Authors: Boehlert Brent B. , Jaeger William K.
Published: October 2010

The water conflict in the Upper Klamath Basin typifies the growing competition between agricultural and environmental water uses. In 2001, drought conditions triggered Endangered Species Act‐related requirements that curtailed irrigation diversions to the Klamath Reclamation Project, costing irrigators tens of millions of dollars. Although this event has significantly elevated the perceived risk of future economic catastrophe in the basin (and therefore the level of conflict among water users), several key changes related to water availability have occurred since 2001. These changes include reduced ESA requirements and increased groundwater pumping capacity, which have lowered the actual risk and severity of future water shortages. In this paper, we use a mathematical programming model to evaluate how these changes alter the likelihood and economic consequences of future shortages. We also consider the effect of more flexible transfers among irrigators via water markets. Our analysis indicates that future drought conditions like those seen in 2001 would have more modest economic impacts than in 2001 and that when combined with contingent groundwater supplementation and water transfer mechanisms such as water markets, both the likelihood and magnitude of economic losses among irrigators would be greatly reduced.
Factors influencing wood mobilization in streams
Authors: Merten Eric , Finlay Jacques , Johnson Lucinda , Newman Raymond , Stefan Heinz , Vondracek Bruce
Published: October 2010

Natural pieces of wood provide a variety of ecosystem functions in streams including habitat, organic matter retention, increased hyporheic exchange and transient storage, and enhanced hydraulic and geomorphic heterogeneity. Wood mobilization is a critical process in determining the residence time of wood. We documented the characteristics and locations of 865 natural wood pieces (>0.05 m in diameter for a portion >1 m in length) in nine streams along the north shore of Lake Superior in Minnesota. We determined the locations of the pieces again after an overbank stormflow event to determine the factors that influenced mobilization of stationary wood pieces in natural streams. Seven of 11 potential predictor variables were identified with multiple logistic regression as significant to mobilization: burial, effective depth, ratio of piece length to effective stream width (length ratio), bracing, rootwad presence, downstream force ratio, and draft ratio. The final model (P< 0.001,r2= 0.39) indicated that wood mobilization under natural conditions is a complex function of both mechanical factors (burial, length ratio, bracing, rootwad presence, draft ratio) and hydraulic factors (effective depth, downstream force ratio). If stable pieces are a goal for stream management then features such as partial burial, low effective depth, high length relative to channel width, bracing against other objects (e.g., stream banks, trees, rocks, or larger wood pieces), and rootwads are desirable. Using the model equation from this study, stewards of natural resources can better manage in‐stream wood for the benefit of stream ecosystems.
Sea‐level fingerprint of continental water and ice mass change from GRACE
Authors: Riva Riccardo E. M. , Bamber Jonathan L. , Lavallée David A. , Wouters Bert
Published: October 2010

The Gravity Recovery and Climate Experiment satellites (GRACE) provide, for the first time, a method to directly measure mass exchange between the land and oceans over time. The dominant components of this exchange are due to continental ice loss/gain and land hydrology. Here, we determine the secular trend in these two components during the GRACE measurement era: 2003–2009. For each component, we model the distinct regional signatures or fingerprints of relative sea‐level (RSL) change, obtaining maxima at low latitudes between ±40° N/S, but with particularly strong regional patterns. We estimate that the total ice and water mass loss from the continents is causing global mean sea‐level to rise by 1.0 ± 0.4 mm/yr. Isolating the ice and hydrological signals, we find that the former is the sole net contributor to the global mean, while the latter dominates regional RSL changes in many coastal areas.
Barchan‐parabolic dune pattern transition from vegetation stability threshold
Authors: Reitz Meredith D. , Jerolmack Douglas J. , Ewing Ryan C. , Martin Raleigh L.
Published: October 2010

Many dune fields exhibit a downwind transition from forward‐pointing barchan dunes to stabilized, backward‐pointing parabolic dunes, accompanied by an increase in vegetation. A recent model predicts this pattern transition occurs when dune surface erosion/deposition rates decrease below a threshold of half the vegetation growth rate. We provide a direct test using a unique data set of repeat topographic surveys across White Sands Dune Field and find strong quantitative support for the model threshold. We also show the threshold hypothesis applied to a barchan dune results naturally in its curvature inversion, as the point of threshold crossing progresses from the horns to the crest. This simple, general threshold framework can be an extremely useful tool for predicting the response of dune landscapes to changes in wind speed, sediment supply, or vegetation growth rate. Near the threshold, a small environmental change could result in a drastic change in dune pattern and activity.
IMF cone angle control of the magnetopause location: Statistical study
Authors: Dušík Š. , Granko G. , Šafránková J. , Němeček Z. , Jelínek K.
Published: October 2010

We investigate the dependence of the magnetopause location on the interplanetary magnetic field (IMF) cone angle (the angle between the IMF and solar wind velocity vectors) in a statistical study based on ≈6500 magnetopause crossings observed by the five THEMIS spacecraft, both at the dayside and flanks. To remove other well‐known effects, we analyze the difference between observed magnetopause radial distances and those predicted by an empirical magnetopause model (scalable by the solar wind dynamic pressure and IMF BZ component). The results demonstrate a systematic increase of the magnetopause distance for radial IMF directions, from ≈0.3 RE at 90° to ≈1.7 RE at 0° or 180° cone angle. Moreover, a stronger dependence of the magnetopause location on the solar wind dynamic pressure than predicted by the current models was observed.
Applying the three‐dimensional model ATHAM to volcanic plumes: Dynamic of large co‐ignimbrite eruptions and associated injection heights for volcanic gases
Authors: Herzog Michael , Graf Hans‐F.
Published: October 2010

Many of the past large volcanic eruptions like Tambora in 1815, Krakatau in 1835, and Pinatubo in 1991 were secondary so called co‐ignimbrite eruptions that were forced over a large area instead of a point source as in the Plinian case. Previous modeling studies were based on one‐dimensional plume models. We used the fully three‐dimensional plume model ATHAM (Active Tracer High‐Resolution Atmospheric Model) to investigate the dynamics and the resulting plume heights of co‐ignimbrite eruptions in an idealized setup. Ash particles as well as a sulfur dioxide (SO2) tracer are included in the model. In the analysis we focus on the behavior of SO2 since the neutral buoyancy height is an ill‐defined parameter for gravitationally settling particles. In contrast to Plinian plumes the co‐ignimbrite plumes develop from multiple updrafts resulting in significantly reduced neutral buoyancy heights. At least a two‐dimensional modeling framework is necessary to capture the relevant dynamical features.
Optical characterization of the growth and spatial structure of a substorm onset arc
Authors: Rae I. J. , Watt C. E. J. , Mann I. R. , Murphy K. R. , Samson J. C. , Kabin K. , Angelopoulos V.
Published: October 2010

We present a detailed case study of the characteristics of auroral forms that constitute the first ionospheric signatures of substorm expansion phase onset. Analysis of the optical frequency and along‐arc (azimuthal) wave number spectra provides the strongest constraint to date on the potential mechanisms and instabilities in the near‐Earth magnetosphere that accompany auroral onset and which precede poleward arc expansion and auroral breakup. We evaluate the frequency and growth rates of the auroral forms as a function of azimuthal wave number to determine whether these wave characteristics are consistent with current models of the substorm onset mechanism. We find that the frequency, spatial scales, and growth rates of the auroral forms are most consistent with the cross‐field current instability or a ballooning instability, most likely triggered close to the inner edge of the ion plasma sheet. This result is supportive of a near‐Earth plasma sheet initiation of the substorm expansion phase. We also present evidence that the frequency and phase characteristics of the auroral undulations may be generated via resonant processes operating along the geomagnetic field. Our observations provide the most powerful constraint to date on the ionospheric manifestation of the physical processes operating during the first few minutes around auroral substorm onset.
Magnetopause expansions for quasi‐radial interplanetary magnetic field: THEMIS and Geotail observations
Authors: Suvorova A. V. , Shue J.‐H. , Dmitriev A. V. , Sibeck D. G. , McFadden J. P. , Hasegawa H. , Ackerson K. , Jelínek K. , Šafránková J. , Němeček Z.
Published: October 2010

We report Time History of Events and Macroscale Interactions during Substorms (THEMIS) and Geotail observations of prolonged magnetopause (MP) expansions during long‐lasting intervals of quasi‐radial interplanetary magnetic field (IMF) and nearly constant solar wind dynamic pressure. The expansions were global: The magnetopause was located more than 3 RE and ∼7 RE outside its nominal dayside and magnetotail locations, respectively. The expanded states persisted several hours, just as long as the quasi‐radial IMF conditions, indicating steady state situations. For an observed solar wind pressure of ∼1.1–1.3 nPa, the new equilibrium subsolar MP position lay at ∼14.5 RE, far beyond its expected location. The equilibrium position was affected by geomagnetic activity. The magnetopause expansions result from significant decreases in the total pressure of the high‐β magnetosheath, which we term the low‐pressure magnetosheath (LPM) mode. A prominent LPM mode was observed for upstream conditions characterized by IMF cone angles less than 20°–25°, high Mach numbers and proton plasma β ≤ 1.3. The minimum value for the total pressure observed by THEMIS in the magnetosheath adjacent to the magnetopause was 0.16 nPa and the fraction of the solar wind pressure applied to the magnetopause was therefore 0.2, extremely small. The equilibrium location of the magnetopause was modulated by a nearly continuous wavy motion over a wide range of time and space scales.
HF ground scatter from the polar cap: Ionospheric propagation and ground surface effects
Authors: Ponomarenko P. V. , St. Maurice J.‐P. , Hussey G. C. , Koustov A. V.
Published: October 2010

In addition to being scattered by the ionospheric field‐aligned irregularities, HF radar signals can be reflected by the ionosphere toward the Earth and then scattered back to the radar by the rugged ground surface. These ground scatter (GS) echoes are responsible for a substantial part of the returns observed by HF radars making up the Super Dual Auroral Radar Network (SuperDARN). While a GS component is conventionally used in studying ionosphere dynamics (e.g., traveling ionospheric disturbances, ULF waves), its potential in monitoring the state of the scattering surface remains largely unexploited. To fill this gap, we investigated diurnal and seasonal variation of the ground echo occurrence and location from a poleward‐looking SuperDARN radar at Rankin Inlet, Canada. Using colocated ionosonde information, we have shown that seasonal and diurnal changes in the high‐latitude ionosphere periodically modulate the overall echo occurrence rate and spatial coverage. In addition, characteristics of GS from a particular geographic location are strongly affected by the state of the underlying ground surface. We have shown that (1) ice sheets rarely produce detectable backscatter, (2) mountain ranges are the major source of GS as they can produce echoes at all seasons of the year, and (3) sea surface becomes a significant source of GS once the Arctic sea ice has melted away. Finally, we discuss how the obtained results can expand SuperDARN abilities in monitoring both the ionosphere and ground surface.
Variation of pCO2 in ocean surface water in response to the passage of a hurricane
Authors: Huang Peisheng , Imberger Jörg
Published: October 2010

The temporal and spatial variations of pCO2 in the ocean surface layer in response to the passage of Hurricane Frances (2004) were investigated with a coupled three‐dimensional hydrodynamic and carbon model. The results showed that the sea surface temperature cooling was the dominant cause of the decrease of surface pCO2, while the entrainment of water with higher CO2 levels partially offset the cooling‐induced decrease. The surface distribution of pCO2 was thus found to mimic the physical deepening processes, with a “right bias” to the hurricane track. The impact of the hurricane on the local air‐sea CO2 exchange extended to about 100 km on both sides of the hurricane track. The whole passage of Hurricane Frances was estimated to have caused a CO2 efflux of about 3.504–10.363 Tg (1 Tg = 1012 g) C from ocean to the atmosphere. Globally, hurricanes in 2004 were estimated to have released a CO2 efflux of 0.047–0.141 Pg (1 Pg = 1015 g) C in total when extrapolating from Hurricane Frances. Under our assumptions, the CO2 efflux caused by the passages of global hurricanes should have increased by about 71.2%–75.0% in past decades.
Mooring observations and numerical modeling of thermal structures in the South China Sea
Authors: Chang Ya‐Ting , Yung Tang Tswen , Chao Shenn‐Yu , Chang Ming‐Huei , Ko Dong S. , Jang Yang Yiing , Liang Wen‐Der , McPhaden Michael J.
Published: October 2010

Three sets of Autonomous Temperature Line Acquisition Systems were deployed in the South China Sea. Gaps aside, the data covered nearly 3 years at the northern station and about 2 years farther south. Fluctuations ranged from episodic to interannual. Internal tides, more diurnal than semidiurnal, were active basinwide. Twelve typhoons passed during measurement periods. The most severe one, typhoon Babs in 1998, caused a temperature drop of over 7°C at 50 m. Despite strong monsoons, only near‐surface temperature showed clear seasonal variations. Intraseasonal variations induced by mesoscale eddy stood out much better at subsurface depths. Propagating eddies aside, some eddies were seasonal and nearly stationary. From daily archives of an eddy‐resolving, data‐assimilating ocean model (East Asian Seas Nowcast/Forecast System), we identified two paradigms leading to the generation of a persistent spring‐summer warm eddy in the central‐western basin. In normal years, a complete cyclonic gyre was driven by a strong winter northeast monsoon. Water piled up along the periphery of the South China Sea. Afterward, a warm eddy could be generated from west of Luzon Island and propagated westward while intensifying. Under a weak northeast monsoon, such as in El Niño years, piled‐up water tended to stay in the southern basin. When the wind relaxed in spring, warm water returned northward to form a warm eddy in the central‐western basin. Transition from SW to NE monsoon also often led to a warm eddy generation in southern latitudes, when the summer eastward jet departing from central Vietnam broke up.
Change of tropical cyclone activity by Pacific‐Japan teleconnection pattern in the western North Pacific
Authors: Choi Ki‐Seon , Wu Chun‐Chieh , Cha Eun‐Jeong
Published: October 2010

This study shows that the Pacific‐Japan (PJ) teleconnection pattern has a significant influence on tropical cyclone (TC) activities over the western North Pacific (WNP) during the boreal summer (July, August, and September). During positive (negative) PJ phase, TCs form at a more northward (southward) location, recurve at a more northeastward (southwestward) location, and frequently pass over the northeast Asian (southeast Asian) region, including Korea and Japan (South China Sea and southern China). In particular, this difference in the TC track between the two phases is observed as a dipole‐like pattern between the regions of Southeast and Northeast Asia. The TC characteristics during the positive PJ phase are caused by the following two stronger atmospheric circulations over the WNP: an anticyclonic circulation centered to the east of Japan and a cyclonic circulation centered to the east of Taiwan. The southeasterly between these two circulations serves as steering flow that TCs move northward toward Korea and Japan from the northeast of the Philippines. Conversely, TCs during the negative PJ phase mainly move westward toward the South China Sea and southern China by the easterly from a stronger anticyclonic circulation centered to the east of Taiwan. As a result of this feature of TC track during the negative PJ phase, TC lifetime is shorter and TC intensity is weaker.
Influence of statistical methods and reference dates on describing temperature change in Alaska
Authors: Bone Christopher , Alessa Lilian , Kliskey Andrew , Altaweel Mark
Published: October 2010

Quantifying temperature trends across multiple decades in Alaska is an essential component for informing policy on climate change in the region. However, Alaska’s climate is governed by a complex set of drivers operating at various spatial and temporal scales, which we posit should result in a sensitivity of trend estimates to the selection of reference start and end dates as well as the choice of statistical methods employed for quantifying temperature change. As such, this study attempts to address three questions: (1) How sensitive are temperature trend estimates in Alaska to reference start dates? (2) To what degree do methods vary with respect to estimating temperature change in Alaska? and (3) How do different reference start dates and statistical methods respond to climatic events that impact Alaska’s temperature? To answer these questions, we examine the use of five methods for quantifying temperature trends at 10 weather stations in Alaska and compare multiple reference start dates from 1958 to 1993 while using a single reference end date of 2003. The results from this analysis demonstrate that, with some methods, the discrepancy in temperature trend estimates between consecutive start dates can be larger than the overall temperature change reported for the second half of the 20th century. Second, different methods capture different climatic patterns, thus influencing temperature trend estimates. Third, temperature trend estimation varies more significantly when a reference start date is defined by an extreme temperature. These findings emphasize that sensitivity analyses should be an essential component in estimating multidecadal temperature trends and that comparing estimates derived from different methods should be performed with caution. Furthermore, the ability to describe temperature change using current methods may be compromised given the increase in temperature extremes in contemporary climate change.
Mountains on Titan: Modeling and observations
Authors: Mitri Giuseppe , Bland Michael T. , Showman Adam P. , Radebaugh Jani , Stiles Bryan , Lopes Rosaly M. C. , Lunine Jonathan I. , Pappalardo Robert T.
Published: October 2010

We have developed a thermal model of Titan's interior to study changes in volume during partial freezing or melting of a subsurface ocean due to heat flux variations from the interior. We find that the long‐term cooling of Titan can cause global volume contraction ΔV/V ∼0.01. We then simulate two‐dimensional contractional deformation of Titan's icy lithosphere, finding that contractional deformation can produce tectonic activity and fold formation. Folds could potentially achieve a topographic height of several kilometers for high local strain (∼0.16), and for high temperature gradients in the ice I shell (order of 10 K km−1), corresponding to an ancient high heat flux from the interior (order of 0.02–0.06 W m−2). Examination of Synthetic Aperture Radar (SAR) imagery obtained by Cassini Radar shows possible evidence of contractional tectonism in the equatorial regions of Titan, although the moderate resolution of the Cassini SAR imagery does not permit an unambiguous geological interpretation.