bluuebunny/crossref_metadata_2025 huggingface dataset:
Fine sediment retention as affected by annual shoot collapse: Sparganium erectum as an ecosystem engineer in a lowland stream
Authors: Asaeda Takashi , Rajapakse Lalith , Kanoh Masahiro
Published: November 2009

To examine the effect of different growth forms of Sparganium erectum (Sparganiaceae) on its sediment trapping and retention characteristics, the plant phenology and morphological attributes based on stands along the edge of a river channel, river flow velocity distribution and sedimentation rates in‐ and outside the stands of a downstream site were examined over a 3‐year period. A decomposition experiment was carried out to determine the respective fragmentation rates of S. erectum shoots and rhizomes. The preliminary monitoring revealed that S. erectum shoots attained distinct phonological stages; submerged in winter, subsequently emerging in late‐spring, while the same cycle was followed by successive secondary cohorts. Our results highlighted that the growth form substantially affected the flow condition in‐ and outside the stands, thus affecting associated sedimentation rates. Although the sedimentation was high if the shoots were submerged in early‐spring, the accumulated fine sediment layer was unleashed following shoot emergence, despite their large biomass and the resulting low flow velocity. The collapse of S. erectum shoots accelerated sedimentation again by increasing constriction to flow, producing a more preferable habitat for its soft roots and rhizomes. The collapse of emergent shoots, therefore, appeared to be a vital part of the inherent phonological cycle of S. erectum. Further, due to the high‐decomposition rate, the collapsed shoots disappeared within 40–60 days, whereas the decomposed materials occupied a large fraction of the floating organic matter. The collapse of shoots increased flow resistance by ∼50%, though the stand area occupied a mere one‐fifth of the channel. The seasonal observations provided further insight into the modification of flows due to the growth and changing growth form affecting associated fine sediment trapping and retention characteristics within the stands, deriving important management implications and highlighting the role of S. erectum as an ecosystem engineer in lowland streams. Copyright © 2009 John Wiley & Sons, Ltd.
The language of poverty: an exploration of the narratives of the poor
Authors: Misturelli Federica , Heffernan Claire
Published: November 2009

Within the development discourse, the narratives of the poor are a well utilized rhetorical tool to describe poverty and its causes. However, narratives can also reveal the beliefs and ‘world‐view’ of the narrators. To explore this influence, the authors applied a discursive approach, to deconstruct the narratives of 101 slum dwellers in Kibera, Nairobi. The results revealed that poverty was largely attributed to external constraints, beyond an individual's control. Despite wanting a better life, participants held low expectations for the future. Hopes and dreams were placed on their children. While risk and uncertainty was a constant theme, large differences were found between genders as to the aspirations for the future. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Influence of methane flow on the microstructure and properties of TiAl‐doped a‐C:H films deposited by middle frequency reactive magnetron sputtering
Authors: Pang Xianjuan , Shi Lei , Wang Peng , Xia Yanqiu , Liu Weimin
Published: November 2009

Hydrogenated TiAl‐doped a‐C:H films were deposited on Si substrates by middle frequency magnetron sputtering TiAl target in argon and methane gas mixture atmosphere. The surface morphology, hardness, chemical nature and bond types of the films were characterized by means of atomic force microscopy (AFM), XPS, Raman spectroscopy and nanoindentation. The friction and wear behaviors of the deposited films were characterized on an UMT‐2MT test system. SEM was utilized to analyze the wear scar and debris on steel balls after sliding on the deposited films under dry friction conditions. The wear rate of the deposited films was calculated from traces of surface profiles taken across the wear track using an optical profile. The results demonstrated that the film deposited at 60 sccm methane flow exhibited higher hardness, as well as low friction coefficient and wear rate, which is attributed to the formation of a graphitized transfer layer. Copyright © 2009 John Wiley & Sons, Ltd.
Seismic performance of a 55‐storey steel plate shear wall
Authors: Youssef Nabih , Wilkerson Ryan , Fischer Kurt , Tunick Daniel
Published: November 2009

The Los Angeles Convention Center Hotel is a 55‐storey steel‐framed steel plate shear wall high‐rise building that takes full advantage of many of the performance‐based design approaches and philosophies. The primary lateral resistance system consists of thin steel plates (3/8–1/4 in. thick) within fully welded WUF‐W moment frames. Additional system stiffness is provided by several storey‐high outrigger trusses at the mid‐height and top of the tower while using buckling‐restrained braces (BRBs) as fuse elements to control the maximum force that the outrigger trusses can develop. Full nonlinear time history record analyses were performed using a suite of seven paired ground motions scaled to a 2475‐year event. Modelling methods were developed for the expected model system behaviour that correlated well with observations from independent research tests. While an essential part of the alternate design verification process, the nonlinear modelling needed to be carefully scrutinized at every step to ensure that unanticipated results of the verification were true behaviours rather than artificial artefacts of model limitations that were not indicative of actual system performance. Extensive analysis and design were performed for the diaphragms of the tower for building set‐back 26th level, as well as the ground floor podium transfer slab. A bounding analysis was performed to ensure essentially elastic behaviour for the backstay of the tower in the concrete basement wells and reinforced concrete mat. Copyright © 2009 John Wiley & Sons, Ltd.
Medical treatments: in association or alone, their roles and their future perspectives
Authors: Reig Maria , Bruix Jordi
Published: November 2009

Management of hepatocellular carcinoma (HCC) is a complex issue, as it needs to take into account the liver disease, the cancer stage and the performance status of the patient. The treatment decision has to be based on robust scientific evidence and for this it is instrumental to have a proper staging system linked to the treatment indication. The BCLC proposal serves these two purposes and has been validated worldwide and endorsed by several scientific associations. The sole systemic therapy that has shown efficacy in improving the survival of HCC patients is sorafenib, an oral kinase inhibitor that blocks the Raf/MEK/ERK pathway and the receptor for VEGFR 2 and PDGFR‐beta. Sorafenib has been recognized as the standard of care for patients who cannot benefit from treatments of higher priority and established efficacy, such as surgical resection, transplantation, ablation and transarterial chemoembolization. Sorafenib has changed the management of HCC, opening the path to combination therapies for patients at advanced stages and to evaluation as an adjuvant for those in earlier evolutionary stages.
Single HCC smaller than 2 cm: surgery or ablation
Authors: Livraghi Tito
Published: November 2009

In the EASL and AASLD guidelines, hepatic resection (HR) is considered the first option for patients in stage 0 (very early HCC). This statement was not based on randomized controlled trials (RCTs) versus other therapies, but on the oncological assumption that HR is the better procedure for obtaining complete tumor ablation including a safety margin. Subsequently, three RCTs compared percutaneous radiofrequency ablation (RFA) versus HR in patients with early HCC. All failed to demonstrate better survival in favor of HR, even though the larger size of the early stage needs a larger area of necrosis. A recent study focused on stage 0 demonstrated a sustained local complete response after RFA comparable with that of HR. All these trials established that RFA is less invasive and associated with lower complication rates and lower costs. These data suggest that RFA can be considered the first option for operable patients with very early HCC. Other options (HR, PEI, selective TAE/TACE) can be used as salvage therapy for the few cases in which RFA is unsuccessful or unfeasible.
Effects of ectomycorrhizal colonization and nitrogen fertilization on morphology of root tips in a Larix gmelinii plantation in northeastern China
Authors: Sun Yue , Gu Jia‐Cun , Zhuang Hai‐Feng , Wang Zheng‐Quan
Published: November 2009

Root morphology is important in understanding root functions in forest ecosystems. However, the effects of ectomycorrhizal colonization and soil nutrient availability on root morphology is not clear. In this study, root morphology in relation to season, soil depth, soil nitrogen (N) availability, and mycorrhizal fungal colonization were investigated in a larch (Larix gmelinii) plantation in northeastern China. The first‐order roots (or root tips) of larch were sampled four times in May, July, and September of 2005, and May of 2006 from two depths of upper soil layer (0–10 and 10–20 cm) in the control and the N‐fertilized plots. The results showed that ectomycorrhizal (ECM) colonization rates for the first‐order roots were reduced by 17% under N fertilization. The peak of root colonization rates occurred in summer and was positively correlated with soil temperature. ECM colonization significantly altered root morphology: root diameter was increased by 19 and 29%, root length shortened by 27 and 25%, and specific root length (SRL) reduced by 16 and 19% for the control and the N‐fertilized plots, respectively. N fertilization led to decreased root length, but did not affect root diameter and SRL. In addition, effects of ECM colonization on root morphology varied with season and soil depth. The observed relationships among ECM fungal colonization, soil N availability, and root‐tip morphology should improve our understanding of how root tips respond to environmental changes in soil in temperate forest ecosystems.
Germs, genomics and global public health
Authors: Pang T.
Published: November 2009

Scientific and technological advances derived from the genomics revolution have a central role to play in dealing with continuing infectious disease threats in the developing world caused by emerging and re-emerging pathogens. These techniques, coupled with increasing knowledge of host-pathogen interactions, can assist in the early identification and containment of outbreaks as well as in the development of preventive vaccination and therapeutic interventions, including the urgent need for new antibiotics. However, the effective application of genomics technologies faces key barriers and challenges which occur at three stages: from the research to the products, from the products to individual patients, and, finally, from patients to entire populations. There needs to be an emphasis on research in areas of greatest need, in facilitating the translation of research into interventions and, finally, the effective delivery of such interventions to those in greatest need. Ultimate success will depend on bringing together science, society and policy to develop effective public health implementation strategies to provide health security and health equity for all peoples.
Did the Berlin Wall really come down on both sides?
Authors: Janša Janez
Published: November 2009

It has become fairly obvious that the EU will be able to realise its original goals in the following decades only by expanding its influence on the outside world. Some people define this influence as the ability to co-design globalisation. But it is important never to lose sight of the founding objectives of the EU. The EU exists because Europeans share basic values of personal, political and economic freedom, values that must be defended.
The Ancient Methods for the Duplication of the Cube
Authors: Mackay J. S.
Published: November 2009

The object of the present paper is merely to exhibit the methods employed by the ancient Greek geometers in their solution of this celebrated problem. A critical discussion of these methods, of the origin of the problem, and perhaps also an account of more recent researches and a notice of the literature connected therewith may form the subject of a subsequent paper.
Plankton Studies in Relation to the Western Mackerel Fishery
Authors: Bullen G. E.
Published: November 2009

The researches here described extended for intermittent periods over the years 1906 and 1907, and were primarily intended to embrace inquiry into the food problem of Pilchard, Herring, and Mackerel frequenting the western part of the English Channel. The observations now recorded form, therefore, a part of a wider series.
On an Experiment in the Keeping of Salmon (Salmo salar) at the Plymouth Laboratory
Authors: Crawshay L. R.
Published: November 2009

For the past two and a half years (1906–8) some salmon, which were reared at the Endsleigh Fishery, have been kept under observation in the aquarium of the Plymouth Laboratory.

In sending these fish as smolts to the Laboratory, the Duke of Bedford wished more particularly to obtain information on two questions: firstly, the character of the food of the salmon during its sojourn in the sea, and secondly, the period of that sojourn intervening between the smolt and grilse stages. These and other points of interest that have arisen will be considered in order in giving a general account of the experiment.
Note on a Hermaphrodite Cod (Gadus morrhua)
Authors: Hefford A. E.
Published: November 2009

On February 27th, the roe of a cod having a testicular portion attached was received at the Laboratory from Messrs. Moodys and Kelly, of Grimsby. It had been taken from a cod caught by a steam trawler fishing in Icelandic waters. Owing to the rough removal of the organs from the fish on the trawling ground, the genital ducts were missing and the region of their origin was ruptured, while the testis had been somewhat damaged in the course of its long journey to Plymouth.
Notes on the Littoral Polychæta of Torquay (Part II.)
Authors: Elwes E. V.
Published: November 2009

It cannot be said that all the species of the Phyllodocidæ have yet been satisfactorily defined, much difference of opinion existing as to the separation of varieties and species. In the accompanying key the nomenclature of Professor Mclntosh has been followed, but those Annelids, which are classed by him as varieties, but which have been hitherto generally accepted as distinct species, are shown separately. The true specific value of the arrangement and nature of the papillæ on the proboscis can only be settled by the examination of numerous individuals from various localities; in the meantime it appears best to consider Annelids differing in these particulars as at least varieties worthy of a name.
On the Artificial Culture of Marine Plankton Organisms
Authors: Allen E. J. , Nelson E. W.
Published: November 2009

The observations to be recorded in this Paper were commenced in March, 1905. They originated in an attempt to find a general method for rearing marine larval forms. Several investigators had previously succeeded in rearing Echinoderms, Molluscs, and Polychætes from artificially fertilized eggs under laboratory conditions, but the process was generally difficult and the results more or less uncertain. The most promising method seemed to be that adopted by Caswell Grave (26), who was able to rear his larvæ by feeding them on diatoms. Grave obtained his diatoms by placing sand, collected from the sea bottom, in aquaria and using such diatoms as developed from this material. All the methods, however, suffered from the uncertainty of not knowing what organisms were introduced into the aquaria in which the larvse were to be reared, either in the original sea-water or along with the food-supply.
On the Species Upogebia stellata and Gebia deltura
Authors: De Morgan W.
Published: November 2009

As remarked by Stebbing (A History of Recent Crustacea, p. 185): “Upogebia, Leach, 1814, was founded to receive another species discovered by the industrious Montagu, and described by him in 1805 (1808) as Cancer astacus stellatus. … It seems to have escaped the notice of writers subsequent to Leach that the earliest name of this genus was Upogebia, which therefore must be retained in preference to Leach's own alteration of it into Gebia, or Risso's Gebios.”
Description of the Laboratory of the Marine Biological Association at Plymouth
Authors: Heape Walter
Published: November 2009

The Laboratory which ia now in the course of erection at Plymouth for the Marine Biological Association, is situated between the south wall of the “Citadel” and the Sound, at a height of 95 feet above the level of the sea. The site, which has been granted to the Association by the War Office, occupies the whole length of King Charles's Curtain, 265 feet, and extends southwards from the Citadel wall 240 ft., giving a surface of, say, 63,600 feet.
Majorization of invariant measures for orientation-reversing maps
Authors: JENKINSON OLIVER , STEEL JACOB
Published: November 2009

Let the invariant probability measures for an orientation-reversing weakly expanding map of the interval [0,1] be partially ordered by majorization. The minimal elements of the resulting poset are shown to be convex combinations of Dirac measures supported on two adjacent fixed points. A consequence is that if f:[0,1]→ℝ is strictly convex, then either its minimizing measure is unique and is a Dirac measure on a fixed point, or f has precisely two ergodic minimizing measures, namely Dirac measures on two adjacent fixed points. In the case where {0,1} is a period-two orbit, with corresponding invariant measure μ01, the maximal elements of the poset are shown to be convex combinations of μ01 with the Dirac measure on either the leftmost, or the rightmost, fixed point. This facilitates the identification of f-maximizing measures when f:[0,1]→ℝ is convex.
Only rational homology spheres admit Ω(f) to be union of DE attractors
Authors: DING FAN , PAN JIANZHONG , WANG SHICHENG , YAO JIANGANG
Published: November 2009

If there exists a diffeomorphism f on a closed, orientable n-manifold M such that the non-wandering set Ω(f) consists of finitely many orientable ( ±) attractors derived from expanding maps, then M is a rational homology sphere; moreover all those attractors are of topological dimension n−2. Expanding maps are expanding on (co)homologies.
Cohomology of substitution tiling spaces
Authors: BARGE MARCY , DIAMOND BEVERLY , HUNTON JOHN , SADUN LORENZO
Published: November 2009

Anderson and Putnam showed that the cohomology of a substitution tiling space may be computed by collaring tiles to obtain a substitution which ‘forces its border’. One can then represent the tiling space as an inverse limit of an inflation and substitution map on a cellular complex formed from the collared tiles; the cohomology of the tiling space is computed as the direct limit of the homomorphism induced by inflation and substitution on the cohomology of the complex. In earlier work, Barge and Diamond described a modification of the Anderson–Putnam complex on collared tiles for one-dimensional substitution tiling spaces that allows for easier computation and provides a means of identifying certain special features of the tiling space with particular elements of the cohomology. In this paper, we extend this modified construction to higher dimensions. We also examine the action of the rotation group on cohomology and compute the cohomology of the pinwheel tiling space.
Pinball billiards with dominated splitting
Authors: MARKARIAN ROBERTO , PUJALS ENRIQUE J. , SAMBARINO MARTÍN
Published: November 2009

We study the dynamics of a type of non-conservative billiards where the ball is ‘kicked’ by the wall giving a new impulse in the direction of the normal. For different types of billiard tables we study the existence of attractors with dominated splitting.
ASYMPTOTIC THEORY FOR EMPIRICAL SIMILARITY MODELS
Authors: Lieberman Offer
Published: November 2009

We consider the stochastic process $Y_t = \sum\nolimits_{i < t} {s_w } (x_t ,x_i)Y_i /\sum\nolimits_{i < t} {s_w } (x_t ,x_i) + \varepsilon _t$, t = 2, …, n, where sw(xt, xi) is a similarity function between the tth and the ith observations and {εt} is a random disturbance term. This process was originally axiomatized by Gilboa, Lieberman, and Schmeidler (2006, Review of Economics and Statistics 88, 433–444) as a way by which agents, or even nature, reason. In the present paper, consistency and the asymptotic distribution of the quasi-maximum likelihood estimator of the parameters of the model are established. Connections to other models and techniques are drawn. In its general form, the model does not fall within any class of nonstationary econometric models for which asymptotic theory is available. For this reason, the developments in this paper are new and nonstandard.
NONSTATIONARITY-EXTENDED WHITTLE ESTIMATION
Authors: Shao Xiaofeng
Published: November 2009

For long memory time series models with uncorrelated but dependent errors, we establish the asymptotic normality of the Whittle estimator under mild conditions. Our framework includes the widely used fractional autoregressive integrated moving average models with generalized autoregressive conditional heteroskedastic-type innovations. To cover nonstationary fractionally integrated processes, we extend the idea of Abadir, Distaso, and Giraitis (2007,Journal of Econometrics141, 1353–1384) and develop the nonstationarity-extended Whittle estimation. The resulting estimator is shown to be asymptotically normal and is more efficient than the tapered Whittle estimator. Finally, the results from a small simulation study are presented to corroborate our theoretical findings.
A REPRESENTATION THEORY FOR POLYNOMIAL COFRACTIONALITY IN VECTOR AUTOREGRESSIVE MODELS
Authors: Franchi Massimo
Published: November 2009

We extend the representation theory of the autoregressive model in the fractional lag operator of Johansen (2008,Econometric Theory24, 651–676). A recursive algorithm for the characterization of cofractional relations and the corresponding adjustment coefficients is given, and it is shown under which condition the solution of the model is fractional of orderdand displays cofractional relations of orderd−band polynomial cofractional relations of orderd− 2b,…,d−cb≥ 0 for integerc; the cofractional relations and the corresponding moving average representation are characterized in terms of the autoregressive coefficients by the same algorithm. Forc= 1 andc= 2 we find the results of Johansen (2008).
Evaluating norms of Pettis integrable functions
Authors: Fernández M. Legua , Ruiz L. M. Sánchez
Published: November 2009

Assuming that (Ω, Σ, μ) is a complete probability space and that X is a Banach space, we evaluate both the semivariation and the variation norm of a wide class of Pettis integrable functions f : Ω → X.
Sharp upper bounds for the density of some invariant measures
Authors: Fornaro Simona , Fusco Nicola , Metafune Giorgio , Pallara Diego
Published: November 2009

We prove sharp upper bounds for invariant measures of Markov processes in ℝN associated with second-order elliptic differential operators with unbounded coefficients.
Two-dimensional incompressible viscous flow around a thin obstacle tending to a curve
Authors: Lacave Christophe
Published: November 2009

Building on a recent work, we consider a two-dimensional viscous fluid in the exterior of a thin obstacle shrinking to a curve, proving convergence to a solution of the Navier–Stokes equations in the exterior of a curve. The uniqueness of the limit solution is also shown.>
Pseudo-immersions of oriented surfaces with one boundary component into the plane
Authors: Yamamoto Minoru
Published: November 2009

Let M be a compact connected oriented surface with exactly one boundary component. A pseudo-immersion of M into the plane is a smooth map such that it has only fold singularities and is an orientation-preserving immersion near the boundary of M. For a pseudo-immersion we study the relation between the winding number of the boundary curve and the number of the singular set components.
On the Benney equation
Authors: Esfahani Amin
Published: November 2009

We study the Benney equation and show that the associated initial-value problem is locally well-posed in Sobolev spaces Hs(ℝ2) for s > −2. Furthermore, we use a priori estimates to establish the global well-posedness for s ≥ 0. We also prove that these results are in some sense sharp. In addition, we obtain some exact travelling-wave solutions of the equation.
Bounds for blow-up time for the heat equation under nonlinear boundary conditions
Authors: Payne L. E. , Schaefer P. W.
Published: November 2009

A differential inequality technique is used to determine a lower bound on the blow-up time for solutions to the heat equation subject to a nonlinear boundary condition when blow-up of the solution does occur. In addition, a sufficient condition which implies that blow-up does occur is determined.
Well-posedness of some initial—boundary-value problems for dynamo-generated poloidal magnetic fields
Authors: Kaiser Ralf , Uecker Hannes
Published: November 2009

Given a bounded domain G ⊂ ℝd, d ≥ 3, we study smooth solutions of a linear parabolic equation with non-constant coefficients in G, which at the boundary have to C1-match with some harmonic function in ℝd \ Ḡ vanishing at spatial infinity.

This problem arises in the framework of magnetohydrodynamics if certain dynamo-generated magnetic fields are considered: for example, in the case of axisymmetry, or for non-radial flow fields, the poloidal scalar of the magnetic field solves the above problem.

We first investigate the Poisson problem in G with the boundary condition described above as well as the associated eigenvalue problem and prove the existence of smooth solutions. As a by-product we obtain the completeness of the well-known poloidal ‘free decay modes’ in ℝ3 if G is a ball. Smooth solutions of the evolution problem are then obtained by Galerkin approximation based on these eigenfunctions.
Decompositions of groups of invertible elements in a ring
Authors: Pavešić Petar
Published: November 2009

We describe decompositions of the group of units of a ring and of its subgroups, induced by idempotents with certain properties. The results apply to several classes of rings, most notably to semi-perfect rings.
Patient-reported complications associated with Campylobacter jejuni infection
Authors: SCHÖNBERG-NORIO D. , MATTILA L. , LAUHIO A. , KATILA M.-L. , KAUKORANTA S.-S. , KOSKELA M. , PAJARRE S. , UKSILA J. , EEROLA E. , SARNA S. , RAUTELIN H.
Published: November 2009

This study aimed to investigate the occurrence of complications, especially musculoskeletal symptoms, after sporadic Campylobacter jejuni enteritis of domestic origin in Finland. This multi-centre cross-sectional study was conducted during a seasonal peak in 2002. Questionnaires were sent to Campylobacter-positive patients, representing different geographical areas, 2 months after collection of positive stool samples. Medical records were viewed in several cases. Besides antimicrobial susceptibility testing C. jejuni isolates were serotyped. A total of 235 patients (58%) returned the questionnaire and 201 C. jejuni-positive patients were finally included in the study. Musculoskeletal symptoms associated with C. jejuni enteritis were frequent (39%); joint pain was most commonly reported (81%). The incidence of reactive arthritis was 4% and that of Achilles enthesopathy and/or heel pain was 9%. Stomach ache during enteritis was associated with the later development of joint pain. Antimicrobial treatment was common but did not prevent complications.
A NOTE ON THEORIES FOR QUASI-INDUCTIVE DEFINITIONS
Authors: BRUNI RICCARDO
Published: November 2009

This paper introduces theories for arithmeticalquasi-inductive definitions(Burgess, 1986) as it has been done for first-order monotone and nonmonotone inductive ones. After displaying the basic axiomatic framework, we provide some initial result in the proof theoretic bounds line of research (the upper one being given in terms of a theory of sets extending Kripke–Platek set theory).
Reduction in Pain Sensitivity from Pharmacological Elevation of Blood Pressure in Persons with Chronically Low Blood Pressure
Authors: Duschek Stefan , Heiss Heike , Buechner Boriana , Schandry Rainer
Published: November 2009

Recent studies have revealed evidence for increased pain sensitivity in individuals with chronically low blood pressure. The present trial explored whether pain sensitivity can be reduced by pharmacological elevation of blood pressure. Effects of the sympathomimetic midodrine on threshold and tolerance to heat pain were examined in 52 hypotensive persons (mean blood pressure 96/61 mmHg) based on a randomized, placebo-controlled, double-blind design. Heat stimuli were applied to the forearm via a contact thermode. Confounding of drug effects on pain perception with changes in skin temperature, temperature sensitivity, and mood were statistically controlled for. Compared to placebo, higher pain threshold and tolerance, increased blood pressure, as well as reduced heart rate were observed under the sympathomimetic condition. Increases in systolic blood pressure between points of measurement correlated positively with increases in pain threshold and tolerance, and decreases in heart rate were associated with increases in pain threshold. The findings underline the causal role of hypotension in the augmented pain sensitivity related to this condition. Pain reduction as a function of heart rate decrease suggests involvement of a baroreceptor-related mechanism in the pain attrition. The increased proneness of persons with chronic hypotension toward clinical pain is discussed.
Effect of Heart Rate Variability on Defensive Reaction and Eating Disorder Symptomatology in Chocolate Cravers
Authors: Rodríguez-Ruiz Sonia , Ruiz-Padial Elisabeth , Vera Nieves , Fernández Carmen , Anllo-Vento Lourdes , Vila Jaime
Published: November 2009

The study examines the effect of heart rate variability (HRV) on the cardiac defence response (CDR) and eating disorder symptomatology in chocolate cravers. Female chocolate cravers (n = 36) and noncravers (n = 36) underwent a psychophysiological test to assess their HRV during a 5-min rest period, followed by three trials to explore the CDR, elicited by an intense white noise, during the viewing of chocolate, neutral, and unpleasant pictures. After the test, participants completed a questionnaire to measure eating disorder symptomatology. The HRV was inversely related to the magnitude of the CDR and to eating disorder symptomatology in chocolate cravers. In addition, the HRV was inversely related to the magnitude of the CDR when viewing unpleasant pictures but not to neutral or chocolate ones, across all participants. These findings support the idea that poor autonomic regulation, indexed by low HRV, plays a relevant role in food craving and uncontrolled eating behavior.
Characterization of site‐specific GPS errors using a short‐baseline network of braced monuments at Yucca Mountain, southern Nevada
Authors: Hill Emma M. , Davis James L. , Elósegui Pedro , Wernicke Brian P. , Malikowski Eric , Niemi Nathan A.
Published: November 2009

We use a short‐baseline network of braced monuments to investigate site‐specific GPS effects. The network has baseline lengths of ∼10, 100, and 1000 m. Baseline time series have root mean square (RMS) residuals, about a model for the seasonal cycle, of 0.05–0.24 mm for the horizontal components and 0.20–0.72 mm for the radial. Seasonal cycles occur, with amplitudes of 0.04–0.60 mm, even for the horizontal components and even for the shortest baselines. For many time series these lag seasonal cycles in local temperature measurements by 23–43 days. This could suggest that they are related to bedrock thermal expansion. Both shorter‐period signals and seasonal cycles for shorter baselines to REP2, the one short‐braced monument in our network, are correlated with temperature, with no lag time. Differences between REP2 and the other stations, which are deep‐braced, should reflect processes occurring in the upper few meters of the ground. These correlations may be related to thermal expansion of these upper ground layers, and/or thermal expansion of the monuments themselves. Even over these short distances we see a systematic increase in RMS values with increasing baseline length. This, and the low RMS levels, suggests that site‐specific effects are unlikely to be the limiting factor in the use of similar GPS sites for geophysical investigations.
Ocean heat transport in Simple Ocean Data Assimilation: Structure and mechanisms
Authors: Zheng Yangxing , Giese Benjamin S.
Published: November 2009

The trend and variability of global ocean heat transport for the period 1958–2004 are investigated using the Simple Ocean Data Assimilation (SODA) analysis. The ocean model is forced with the European Center for Medium Range Weather Forecast (ECMWF) ERA‐40 atmospheric reanalysis winds from 1958 to 2001 and with QuikSCAT winds from 2002 to 2004. The assimilation is based on a sequential estimation algorithm, with observations from the historical archive of hydrographic profiles supplemented by ship intake measurements, moored hydrographic observations and remotely sensed sea surface temperature. Heat transport is calculated using temperature and velocity from the ocean analysis. Mean heat transport from the analysis generally agrees with previously published estimates from observational and modeling studies. Trends of heat transport show a range of behaviors. In the Atlantic and Pacific Oceans there is mostly increasing poleward heat transport with two important exceptions. In the Atlantic Ocean there is decreasing heat transport around 50°N and 60°N, and in both the Atlantic and Pacific Oceans there is decreasing heat transport near 10°S. There is also prominent interannual and decadal variability in all of the ocean basins. The results suggest that ocean heat transport variability is primarily determined by the strength of the meridional overturning circulation (MOC), which is controlled by complex processes governing fresh water flux in the northern North Atlantic and surface wind stress. However, the role of temperature variability increases at high latitude, particularly in the northern North Atlantic Ocean. Eddies play an important role in heat transport in the Gulf Stream and its extension in the Atlantic Ocean, and the Kuroshio and its extension in the Pacific Ocean and enhanced Subtropical cells (STCs) affect heat transport estimates in the tropics. In the northern North Atlantic Ocean, a small increase in meridional heat transport and a slight weakening of MOC are detected. Weakening in the northern North Atlantic MOC mainly arises from a freshening in the Labrador Sea and slowdown of the overflows from the Nordic Seas into the northern North Atlantic Ocean. Trends in North Atlantic surface momentum forcing are uniform across several atmospheric reanalyses, however there is less agreement in the role of precipitation in forcing trends of MOC and this exists as a primary source of uncertainty in our analysis.
The High‐Lakes Project
Authors: Cabrol Nathalie A. , Grin Edmond A. , Chong Guillermo , Minkley Edwin , Hock Andrew N. , Yu Youngseob , Bebout Leslie , Fleming Erich , Häder Donat P. , Demergasso Cecilia , Gibson John , Escudero Lorena , Dorador Cristina , Lim Darlene , Woosley Clayton , Morris Robert L. , Tambley Cristian , Gaete Victor , Galvez Matthieu E. , Smith Eric , Uskin‐Peate Ingrid , Salazar Carlos , Dawidowicz G. , Majerowicz J.
Published: November 2009

The High Lakes Project is a multidisciplinary astrobiological investigation studying high‐altitude lakes between 4200 m and 6000 m elevation in the Central Andes of Bolivia and Chile. Its primary objective is to understand the impact of increased environmental stress on the modification of lake habitability potential during rapid climate change as an analogy to early Mars. Their unique geophysical environment and mostly uncharted ecosystems have added new objectives to the project, including the assessment of the impact of low‐ozone/high solar irradiance in nonpolar aquatic environments, the documentation of poorly known ecosystems, and the quantification of the impact of climate change on lake environment and ecosystem. Data from 2003 to 2007 show that UV flux is 165% that of sea level with maximum averaged UVB reaching 4 W/m2. Short UV wavelengths (260–270 nm) were recorded and peaked at 14.6 mW/m2. High solar irradiance occurs in an atmosphere permanently depleted in ozone falling below ozone hole definition for 33–36 days and between 30 and 35% depletion the rest of the year. The impact of strong UVB and UV erythemally weighted daily dose on life is compounded by broad daily temperature variations with sudden and sharp fluctuations. Lake habitat chemistry is highly dynamical with notable changes in yearly ion concentrations and pH resulting from low and variable yearly precipitation. The year‐round combination of environmental variables define these lakes as end‐members. In such an environment, they host ecosystems that include a significant fraction of previously undescribed species of zooplankton, cyanobacterial, and bacterial populations.
Methane sources feeding cold seeps on the shelf and upper continental slope off central Oregon, USA
Authors: Torres Marta E. , Embley Robert W. , Merle Susan G. , Tréhu Anne M. , Collier Robert W. , Suess Erwin , Heeschen Katja U.
Published: November 2009

We report on a bathymetric mapping and remotely operated vehicle surveys along the 100–600 m region offshore Oregon from 43°50′N to 44°18′N. We interpret our results in light of available geophysical data, published geotectonic models, and analogous observations of fluid venting and carbonate deposition from 44°30′N to 45°00′N. The methane seepage is defined by juxtaposition of a young prism, where methane is generated by bacterial activity and its release is modulated by gas hydrate dynamics, against older sequences that serve as a source of thermogenic hydrocarbons that vent in the shelf. We hypothesize that collision of a buried ridge with the Siletz Terrane results in uplift of gas hydrate bearing sediments in the oncoming plate and that the resulting decrease in pressure leads to gas hydrate dissociation and methane exolution, which, in turn, may facilitate slope failure. Oxidation of the released methane results in precipitation of carbonates that are imaged as high backscatter along a 550 ± 60 m benthic corridor.
Global climate imprint on seismic noise
Authors: Stutzmann Eléonore , Schimmel Martin , Patau Geneviève , Maggi Alessia
Published: November 2009

In the absence of earthquakes, oceanic microseisms are the strongest signals recorded by seismic stations. Using the GEOSCOPE global seismic network, we show that the secondary microseism spectra have global characteristics that depend on the station latitude and on the season. In both hemispheres, noise amplitude is larger during local winter, and close to the equator, noise amplitude is stable over the year. There is an excellent correlation between microseism amplitude variations over the year and changes in the highest wave areas. Considering the polarization of the secondary microseisms, we show that stations in the Northern Hemisphere and close to the equator record significant changes of the secondary microseism source azimuth over the year. During Northern Hemisphere summer, part or all of the sources are systematically located farther toward the south than during winter. Stations in French Guyana (MPG) and in Algeria (TAM) record microseisms generated several thousand kilometers away in the South Pacific Ocean and in the Indian Ocean, respectively. Thus, secondary microseism sources generated by ocean waves which originate in the Southern Hemisphere can be recorded by Northern Hemisphere stations when local sources are weak. We also show, considering a station close to Antarctica, that primary and secondary microseism noise amplitudes are strongly affected by changes of the sea ice floe and that sources of these microseisms are in different areas. Microseism recording can therefore be used to monitor climate changes.
Using pressure transients within a polymeric membrane for gas composition measurements
Authors: De Gregorio Sofia , Camarda Marco , Cappuzzo Santo , Gurrieri Sergio
Published: November 2009

The properties of polymeric membranes and measurements of gas concentrations are common elements of industrial processes and scientific research. Here we report a methodology whereby pressure measurements inside a closed polymeric membrane tube can be quantitatively related to the composition of the external gas. This approach is founded on the different rates at which the gases permeate into and out of the interior of the polymeric tube. The difference between the amounts of gas entering and leaving the tube triggers a pressure transient. The features of this transient depend on the species of the involved gases and their partial pressures and under certain conditions, allow the concentration of one or more species to be estimated. We outline the theoretical principles behind the proposed methodology and conduct laboratory tests on a device that could be adaptable to continuous measurements of CO2 partial pressure in field applications.
Regionally coherent Little Ice Age cooling in the Atlantic Warm Pool
Authors: Richey Julie N. , Poore Richard Z. , Flower Benjamin P. , Quinn Terrence M. , Hollander David J.
Published: November 2009

We present 2 new decadal‐resolution foraminiferal Mg/Ca‐SST records covering the past 6–8 centuries from the northern Gulf of Mexico (GOM). These records provide evidence for a Little Ice Age (LIA) cooling of 2°C, consistent with a published Mg/Ca record from Pigmy Basin. Comparison of these 3 records with existing SST proxy records from the GOM‐Caribbean region show that the magnitude of LIA cooling in the Atlantic Warm Pool (AWP) was significantly larger than the mean hemispheric cooling of <1°C. We propose that a reduction in the intensity and spatial extent of the AWP during the LIA, combined with associated changes in atmospheric circulation may account for the regional SST patterns observed in the GOM‐Caribbean region during the LIA.
No evidence for externally triggered substorms based on superposed epoch analysis of IMF Bz
Authors: Freeman M. P. , Morley S. K.
Published: November 2009

Superposed epoch analyses have shown that, on average, the interplanetary magnetic field (IMF) turns northward close to substorm onset. This has been commonly accepted as evidence for the substorm onset being triggered by a rapid northward turning of the IMF. Here we show that the tendency arises in any superposed epoch analysis of the IMF in which event onset is biased to occur for southward IMF, irrespective of a coincident rapid northward turning of the IMF. The overall IMF variation found in the largest superposed epoch analysis of this kind is also well reproduced using a Minimal Substorm Model in which substorm onsets are determined without the requirement of a northward IMF turning trigger. We discuss the explanation underlying these results and conclude that there is no conclusive evidence in favour of the hypothesis that substorm onsets are triggered by a rapid northward turning of the IMF.
Decadal variability in biogeochemical models: Comparison with a 50‐year ocean colour dataset
Authors: Henson Stephanie A. , Raitsos Dionysios , Dunne John P. , McQuatters‐Gollop Abigail
Published: November 2009

Assessing the skill of biogeochemical models to hindcast past variability is challenging, yet vital in order to assess their ability to predict biogeochemical change. However, the validation of decadal variability is limited by the sparsity of consistent, long‐term biological datasets. The Phytoplankton Colour Index (PCI) product from the Continuous Plankton Recorder survey, which has been sampling the North Atlantic since 1948, is an example of such a dataset. Converting the PCI to chlorophyll values using SeaWiFS data allows a direct comparison with model output. Here we validate decadal variability in chlorophyll from the GFDL TOPAZ model. The model demonstrates skill at reproducing interannual variability, but cannot simulate the regime shifts evident in the PCI data. Comparison of the model output, data and climate indices highlights under‐represented processes that it may be necessary to include in future biogeochemical models in order to accurately simulate decadal variability in ocean ecosystems.
Self‐similar slip pulses during rate‐and‐state earthquake nucleation
Authors: Rubin Allan M. , Ampuero Jean‐Paul
Published: November 2009

For a wide range of conditions, earthquake nucleation zones on rate‐ and state‐dependent faults that obey either of the popular state evolution laws expand as they accelerate. Under the “slip” evolution law, which experiments show to be the more relevant law for nucleation, this expansion takes the form of a unidirectional slip pulse. In numerical simulations these pulses often tend to approach, with varying degrees of robustness, one of a few styles of self‐similar behavior. Here we obtain an approximate self‐similar solution that accurately describes slip pulses growing into regions initially sliding at steady state. In this solution the length scale over which slip speeds are significant continually decreases, being inversely proportional to the logarithm of the maximum slip speed Vmax, while the total slip remains constant. This slip is close to Dc(1−a/b)−1, where Dc is the characteristic slip scale for state evolution and a and b are the parameters that determine the sensitivity of the frictional strength to changes in slip rate and state. The pulse has a “distance to instability” as well as a “time to instability,” with the remaining propagation distance being proportional to (1−a/b)−2 [ln(Vmaxθbg/Dc)]−1, where θbg is the background state into which the pulse propagates. This solution provides a reasonable estimate of the total slip for pulses growing into regions that depart modestly from steady state.
Low‐frequency exchange of mass between ocean basins
Authors: Chambers Don P. , Willis Josh K.
Published: November 2009

We examine the Gravity Recovery and Climate Experiment (GRACE) data and output from an ocean model to quantify mass fluctuations for the Pacific, Atlantic, and Indian Ocean basins from August 2002 until December 2008. The monthly spatial mean is removed to study interbasin mass exchange. We find a seasonal exchange of mass between the Atlantic and Pacific that is similar to one documented previously, although the amplitude observed by GRACE is about 20% lower than that simulated by an ocean model. There are also significant fluctuations with periods longer than 1 year. We find large interannual exchanges in 2005 and 2007, with GRACE observing yearly averaged mass anomalies in the Pacific that are about 30–40% larger than simulated by a model. This is shown to be from significant interannual mass losses from the Indian Ocean that are observed by GRACE but not simulated by the model. A longer run of the model, from 1976 to 2008, suggests that such interbasin mass exchanges are a regular occurrence and can last for as long as a couple of decades.