bluuebunny/crossref_metadata_2025 huggingface dataset:
Parasite infracommunities of a specialized marine fish species in a compound community dominated by generalist parasites
Authors: Lanfranchi A.L. , Rossin M.A. , Timi J.T.
Published: May 2009

The structure and composition of parasite communities of Mullus argentinae were analysed under two alternative hypotheses in a sample of 75 specimens caught off Mar del Plata, Argentina (38°27′S, 57°90′W). The first, based on the dominance of trophically transmitted larval parasites of low host-specificity among fish species in the region, predicts that infracommunities will be random subsets of regionally available species. The second, based on previous studies on other mullids, predicts that infracommunities will be dominated by adult digeneans. The parasite fauna of goatfishes was mainly composed of endoparasites, with metacercariae of Prosorhynchus australis accounting for most individual parasites and greatly affecting infracommunity descriptors. Its importance was reinforced by the low number of trophically transmitted larval parasites. Both hypotheses were refuted; parasite communities were not dominated either by trophically transmitted larval parasites of low host-specificity or by adult digeneans. Prosorhynchus australis was the only species displaying any degree of phylogenetic specificity. Therefore, the influence of phylogenetic factors seems to exceed that of ecological ones in determining the observed structure of infracommunities. However, it is precisely host ecology that allows P. australis to become the determinant of infracommunity structure by constraining the acquisition of other parasites. Studies aiming to determine the relative importance of evolutionary and ecological processes as structuring forces of parasite communities should take into account not only the identity and specificity of their component parasites, but also their availability in the compound community.
Patterns of laryngopharyngeal and gastroesophageal reflux
Authors: Sato K , Umeno H , Chitose S , Nakashima T
Published: May 2009

Objectives:

Double-probe, 24-hour pH monitoring remains the ‘gold standard’ for the diagnosis of laryngopharyngeal reflux disease, even though there is no consensus on how to interpret the data collected.

Methods:

Tetra-probe, 24-hour pH monitoring was performed in 56 patients with suspected laryngopharyngeal reflux, in order to investigate patterns of laryngopharyngeal and gastroesophageal reflux.

Results:

The number of reflux episodes and the total and percentage time periods spent with pH < 4.0 were correlated with the distance of the probe from the lower oesophageal sphincter. The number of reflux episodes and the total and percentage time periods with pH < 4.0 were greater when patients were upright (i.e. during the daytime). There were few laryngopharyngeal reflux events recorded for pH levels of <4.0; however, there were a significant number of laryngopharyngeal reflux events recorded for pH levels of <5.0, a level capable of causing laryngopharyngeal reflux disease. When a pH level of <5.0 was used, the number, total time and percentage time of laryngopharyngeal reflux episodes was greater during the supine period (i.e. during sleeping) in a quarter of the cases, compared with results when a pH of <4.0 was used.

Conclusions:

It is valid to use a pH level of 5.0 as indicative of laryngopharyngeal reflux in the hypopharynx.
Surgical treatment of labyrinthine fistula in patients with cholesteatoma
Authors: Ueda Y , Kurita T , Matsuda Y , Ito S , Nakashima T
Published: May 2009

Labyrinthine fistula is one of the most common complications of chronic otitis media associated with cholesteatoma. The optimal management of labyrinthine fistula, however, remains controversial. Between 1995 and 2005, labyrinthine fistulae were detected in 31 (6 per cent) patients in our institution. The canal wall down technique was used in 27 (87 per cent) patients. The cholesteatoma matrix was completely removed in the first stage in all patients. Bone dust and/or temporalis fascia was inserted to seal the fistula in 29 (94 per cent) patients. A post-operative hearing test was undertaken in 27 patients; seven (26 per cent) patients showed improved hearing, 17 (63 per cent) showed no change and three (11 per cent) showed a deterioration. The study findings indicate that there are various treatment strategies available for cholesteatoma, and that the treatment choice should be based on such criteria as auditory and vestibular function, the surgeon's ability and experience, and the location and size of the fistula.
Superselective, intra-arterial, rapid infusion chemotherapy for external auditory canal carcinoma
Authors: Ueda Y , Kurita T , Matsuda Y , Ito S , Nakashima T
Published: May 2009

Previously, the treatment of carcinoma of the external auditory canal has mainly involved surgical resection. In order to enable organ preservation and to obtain cancer-free surgical margins, we introduced the use of superselective, intra-arterial, rapid infusion chemotherapy combined with radiotherapy to treat this condition.

We reviewed our patients' tumour stages, feeding arteries and clinical outcomes. Tumours were staged according to the Pittsburgh staging system. Chemotherapy was administered intra-arterially in the angiography suite via transfemoral catheterisation of the feeding arteries. Four patients underwent superselective, intra-arterial, rapid infusion chemo-radiotherapy. A complete response was obtained in all four patients. The overall toxic side effects were modest.

Superselective, intra-arterial, rapid infusion chemotherapy can be an effective, organ-preserving treatment for external auditory canal carcinoma, with a high cure rate.
Effect of tympanic membrane perforation on middle-ear sound transmission
Authors: Matsuda Y , Kurita T , Ueda Y , Ito S , Nakashima T
Published: May 2009

Tympanic membrane perforation causes a sound conduction disturbance, and the size of this conduction disturbance is proportional to the perforation area. However, precise evaluation of perforation size is difficult, and there are few detailed reports addressing this issue. Furthermore, such evaluation becomes more difficult for irregularly shaped perforations. This study conducted a quantitative evaluation of tympanic membrane perforations, using image analysis equipment.

A significant correlation was found between the degree of sound conduction disturbance and the perforation area; this correlation was greater at low frequencies following a traumatic perforation. The conductive disturbance associated with chronic otitis media was significantly greater at low frequencies. Circular perforations caused only minor conduction disturbance. Perforations in the anteroinferior quadrant were associated with greater conduction disturbance. Traumatic spindle-shaped perforations and malleolar perforations were associated with greater conduction disturbance.
Papilloedema secondary to venous sinus thrombosis following glomus jugulare tumour surgery
Authors: Izadi S , Karkos P D , Krishnan R , Hsuan J , Lesser T H J
Published: May 2009

Objective:

We present a case of a patient who had undergone embolisation and resection of a left glomus jugulare tumour, who presented three weeks post-operatively with magnetic resonance venography confirmed symptomatic cerebral venous sinus thrombosis.

Method:

We present a case report and a review of the world literature concerning glomus jugulare tumours and cerebral venous sinus thrombosis.

Case report:

A 42-year-old man presented with blurred vision and reduced Snellen visual acuity just three weeks after glomus jugulare tumour surgery. Fundoscopy revealed bilateral haemorrhagic optic disc oedema. Urgent magnetic resonance venography confirmed a left lateral venous sinus thrombosis. It was felt that this was responsible for inadequate cerebrospinal fluid drainage, resulting in raised intracranial pressure and papilloedema.

Conclusion:

To the authors' knowledge, this is the first account of a magnetic resonance venography confirmed venous sinus thrombosis and secondary papilloedema following glomus jugulare tumour surgery. Patients undergoing surgery involving resection or manipulation of the internal jugular vein may be at higher risk of developing thrombosis superior to the level of resection, and magnetic resonance venography ought to be considered an important diagnostic adjunct.
The inhaled pin inaccessible to the bronchoscope: a management conundrum
Authors: Harischandra D V T , Swanevelder J , Firmin R K
Published: May 2009

Objective:

The inhaled sharp foreign body is usually amenable to bronchoscopic extraction. When this fails, management poses a challenge. We present a logical approach to the inhaled pin inaccessible to the bronchoscope.

Case report:

A 12-year-old girl presented to the accident and emergency unit after accidentally inhaling a pin. Multiple attempts with both rigid and flexible bronchoscopy failed to access the pin, which had lodged distally in the anteromedial basal segment of the left lung. Eventually, the pin was extracted at thoracotomy.

Conclusion:

We discuss the reasons for extracting such pins, as opposed to leaving them in situ, and when to proceed from endoscopy to open surgery. Such knowledge is useful, not only to guide the multidisciplinary team in their combined approach to this unique challenge, but also to explain to the patient the rationale for the proposed treatment protocol.
Residual symptoms after remission of major depressive disorder with citalopram and risk of relapse: a STAR*D report
Authors: Nierenberg A. A. , Husain M. M. , Trivedi M. H. , Fava M. , Warden D. , Wisniewski S. R. , Miyahara S. , Rush A. J.
Published: May 2009

Background

Many patients with major depressive disorder (MDD) who experience full symptomatic remission after antidepressant treatment still have residual depressive symptoms. We describe the types and frequency of residual depressive symptoms and their relationship to subsequent depressive relapse after treatment with citalopram in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) trial.

Method

Participants in primary (n=18) and psychiatric (n=23) practice settings were openly treated with citalopram using measurement-based care for up to 14 weeks and follow-up for up to 1 year. We assessed 943 (32.8% of 2876) participants who met criteria for remission to determine the proportions with individual residual symptoms and any of the nine DSM-IV criterion symptom domains to define a major depressive episode. At each visit, the 16-item Quick Inventory of Depressive Symptomatology, Self-Report (QIDS-SR16) and the self-report Frequency, Intensity, and Burden of Side Effects Rating (FIBSER) scale were used to assessed depressive symptoms and side-effects respectively.

Results

More than 90% of remitters had at least one residual depressive symptom (median=3). The most common were weight increase (71.3%) and mid-nocturnal insomnia (54.9%). The most common residual symptom domains were sleep disturbance (71.7%) and appetite/weight disturbance (35.9%). Those who remitted before 6 weeks had fewer residual symptoms at study exit than did later remitters. Residual sleep disturbance did not predict relapse during follow-up. Having a greater number of residual symptom domains was associated with a higher probability of relapse.

Conclusions

Patients with remission of MDD after treatment with citalopram continue to experience selected residual depressive symptoms, which increase the risk of relapse.
Research in applied linguistics and language teaching and learning in Singapore (2000–2007)
Authors: Rubdy Rani , Tupas T. Ruanni F.
Published: May 2009

In this review of research in applied linguistics and language teaching and learning in Singapore, more than one hundred national publications for the period 2000–2007 will be reviewed. Since this period encompasses certain changes that were introduced in Singapore schools at the start of the new millennium, it would be appropriate to take stock of the studies that showcase these changes. These studies fall under five main areas of local research: norms, standards and models; English language curriculum and policy; reading and writing instruction and research; mother tongue teaching and learning; and the teaching of English to international students. In this review, representative work under each research area will be discussed, and this will be done within the broad historical and sociopolitical context of research in Singapore. The results of the review suggest that practical concerns assume priority over theoretical issues, which are relegated to secondary importance. This can be explained in terms of the role of the state in education reform and governance and its top–down decision-making processes, the impact of globalization on education, and the role of education in the management of race relations in the country.
Robust visual odometry for vehicle localization in urban environments
Authors: Parra I. , Sotelo M. A. , Llorca D. F. , Ocaña M.
Published: May 2009

This paper describes a new approach for estimating the vehicle motion trajectory in complex urban environments by means of visual odometry. A new strategy for robust feature extraction and data post-processing is developed and tested on-road. Images from scale-invariant feature transform (SIFT) features are used in order to cope with the complexity of urban environments. The obtained results are discussed and compared to previous works. In the prototype system, the ego-motion of the vehicle is computed using a stereo-vision system mounted next to the rear view mirror of the car. Feature points are matched between pairs of frames and linked into 3D trajectories. The distance between estimations is dynamically adapted based on re-projection and estimation errors. Vehicle motion is estimated using the non-linear, photogrametric approach based on RAndom SAmple Consensus (RANSAC). The final goal is to provide on-board driver assistance in navigation tasks, or to provide a means of autonomously navigating a vehicle. The method has been tested in real traffic conditions without using prior knowledge about the scene or the vehicle motion. An example of how to estimate a vehicle's trajectory is provided along with suggestions for possible further improvement of the proposed odometry algorithm.
A cost-effective robotic solution for the cleaning of ships' hulls
Authors: Iborra A. , Pastor J. A. , Alonso D. , Alvarez B. , Ortiz F. J. , Navarro P. J. , Fernández C. , Suardiaz J.
Published: May 2009

Hull cleaning before repainting is a key operation in the maintenance of ships. For more than a decade, a means to improve this operation has been sought through robotization and the use of different techniques such as grit blasting and ultra high pressure water jetting. Despite this, it continues to be standard practice in shipyards that this process is carried out manually. This paper presents a family of robots that aims to offer important improvements to the process as well as satisfying, to a great extent, all the operative requirements of efficiency, security, and respect for the environment that shipyards nowadays demand. It is described the family of devices with emphasis on the mechanical design. This set consists of two vertical robotic towers and a robot climber. In addition, it is shown the control architecture of the global system. Finally, operative results are presented together with a comparison between the performance achieved in shipyards through the use of these robots and those obtained with a manual process.
A large dataset for the evaluation of ontology matching
Authors: Giunchiglia Fausto , Yatskevich Mikalai , Avesani Paolo , Shivaiko Pavel
Published: May 2009

Recently, the number of ontology matching techniques and systems has increased significantly. This makes the issue of their evaluation and comparison more severe. One of the challenges of the ontology matching evaluation is in building large-scale evaluation datasets. In fact, the number of possible correspondences between two ontologies grows quadratically with respect to the numbers of entities in these ontologies. This often makes the manual construction of the evaluation datasets demanding to the point of being infeasible for large-scale matching tasks. In this paper, we present an ontology matching evaluation dataset composed of thousands of matching tasks, called TaxME2. It was built semi-automatically out of the Google, Yahoo, and Looksmart web directories. We evaluated TaxME2 by exploiting the results of almost two-dozen of state-of-the-art ontology matching systems. The experiments indicate that the dataset possesses the desired key properties, namely it iserror-free,incremental,discriminative,monotonic, andhardfor the state-of-the-art ontology matching systems.
The abelianization of a symmetric mapping class group
Authors: SATO MASATOSHI
Published: May 2009

Let Σg,r be a compact oriented surface of genus g with r boundary components. We determine the abelianization of the symmetric mapping class group (g,r)(p2) of a double unbranched cover p2: Σ2g − 1,2r → Σg,r using the Riemann constant, Schottky theta constant, and the theta multiplier. We also give lower bounds on the order of the abelianizations of the level d mapping class group.
Spain's Record Organ Donations: Mining Moral Conviction
Authors: GIL-DÍAZ CARLOS
Published: May 2009

Over the past 20 years, organ donations in Spain have soared from modest numbers to the highest rate in the world. In the brief span between 1998 and 2005, donation rates have increased from 14 per million population (p.m.p.) to 35.1 p.m.p. By way of comparison the number in the United States is 25.5 donations p.m.p.
Bioética sin Más: The Past, Present, and Future of a Latin American Bioethics
Authors: RODRÍGUEZ DEL POZO PABLO , MAINETTI JOSÉ A.
Published: May 2009

The most casual conversation about Latin American life, politics, or culture can turn into a shouting match just by innocently asking the table to define what Latin America is. Some will dismiss the term as an American (or French or Jesuit) construct that fails to capture the geographic and cultural complexities of the former Spanish colonies. Others will fervently argue that despite its imprecision—or perhaps because of it—this lexical wild card connotes an aspiration of brotherhood against colonialist threats past and present. When the dust settles, both sides will likely concede that the question is a beguiling one indeed.
Bioethics in the Americas: North and South—A Personal Story
Authors: DRANE JAMES F.
Published: May 2009

Where I am, in the late 70s, I find myself being asked to do far more than I am able. I'm at the stage when everyone assumes that I don't have any real work, so it's OK to ask for things. Increasingly the things I'm asked to do are historical: What was it like back then? When did you start doing this or that? How did this or that get started? I guess I'm in the penultimate period. I'm still working every day, much harder than I would like, and upset by the fact that my memory is not working the way it should. With this public confession, I'll now start my penance, that is, to do a little personal history of my involvement with bioethics first here in the United States, then in Spain and Spanish-speaking nations of Latin America.
Adolescent Decisionmaking, Part I: Introduction
Authors: HESTER D. MICAH
Published: May 2009

This CQ department is dedicated to bringing noted bioethicsts together in order to debate some of the most perplexing contemporary bioethics issues. You are encouraged to contact “The Great Debates” department editor, D. Micah Hester (hesterdm@uams.ed), UAMS/Humanities, 4301 W. Markham St. #646, Little Rock, AR 72205, with any suggestions for debate topics and interlocutors you would like to see published herein.
PROCYCLICAL SOLOW RESIDUALS WITHOUT TECHNOLOGY SHOCKS
Authors: Clarke Andrew J. , Johri Alok
Published: May 2009

Most real business cycle models have a hard time jointly explaining the twin facts of strongly procyclical Solow residuals and extremely low correlations between wages and hours. We present a model that delivers both these results without using exogenous variation in total factor productivity (technology shocks). The key innovation of the paper is to add learning-by-doing to firms' technology. As a result, firms optimally vary their prices to control the amount of learning, which in turn influences future productivity. We show that exogenous variation in labor wedges (preference shocks) measured from aggregate data deliver around 50% of the standard deviation in the efficiency wedge (Solow residual) as well as realistic second moments for key aggregate variables, which is in sharp contrast to the model without learning-by-doing.
THE WEALTH DISTRIBUTION AND THE DEMAND FOR STATUS
Authors: Luo Yulei , Young Eric R.
Published: May 2009

Standard economic theories of asset markets assume that assets are valued entirely for the consumption streams they can finance. This paper examines the introduction of the demand for status (as a function of wealth) into a model of uninsurable idiosyncratic risk—the “spirit of capitalism” (“soc”) assumption. We find that soc preferences lead to less inequality in wealth; placing wealth into the utility function leads to a shrinking wealth distribution. The drop in wealth concentration is smaller if the utility function implies status is a luxury good, but no parametrization leads to higher wealth Gini coefficients than the benchmark case. We then consider the consequences of revenue-neutral tax reforms with and without soc preferences, finding that they make little difference for this policy experiment.
INFLATION RISK AND OPTIMAL MONETARY POLICY
Authors: Gavin William T. , Keen Benjamin D. , Pakko Michael R.
Published: May 2009

This paper shows that the optimal monetary policies recommended by New Keynesian models still imply a large amount of inflation risk. We calculate the term structure of inflation uncertainty in New Keynesian models when the monetary authority adopts the optimal policy. When the monetary policy rules are modified to include some weight on a price path, the economy achieves equilibria with substantially lower long-run inflation risk. With either sticky prices or sticky wages, a price path target reduces the variance of inflation by an order of magnitude more than it increases the variability of the output gap.
DOES THE TIMING OF THE CASH-IN-ADVANCE CONSTRAINT MATTER FOR OPTIMAL FISCAL AND MONETARY POLICY?
Authors: Chugh Sanjay K.
Published: May 2009

I demonstrate that the precise timing of financial markets and goods markets in a simple cash good/credit good model does not matter for the main results in the Ramsey literature on optimal fiscal and monetary policy. In Ramsey models based on Lucas and Stokey [Journal of Monetary Economics12, 55–93 (1983)] and Chari, Christiano, and Kehoe [Journal of Money, Credit, and Banking23, 519–539 (1991)], nominal money holdings are freely adjustable in response to shocks in the period in which they will be used to purchase consumption. In contrast, under Svensson [Journal of Political Economy93, 919–944 (1985)] timing, nominal balances cannot be adjusted in the period they will be used. The broad finding is that benchmark Ramsey results are not very sensitive to this slight, ultimately ad hoc, modification. In particular, optimal inflation continues to display very high variability just as in the original models, although this can differ depending on exactly which exogenous processes are driving the economy. That the basic results in the Ramsey literature are not sensitive to the choice of cash/credit timing is reassuring as Ramsey analysis is applied to an ever-expanding set of model environments.
Mn Valency at La0.7Sr0.3MnO3/SrTiO3 (0 0 1) Thin Film Interfaces
Authors: Riedl Thomas , Gemming Thomas , Dörr Kathrin , Luysberg Martina , Wetzig Klaus
Published: May 2009

This article presents a (scanning) transmission electron microscopy (TEM) study of Mn valency and its structural origin at La0.7Sr0.3MnO3/SrTiO3(0 0 1) thin film interfaces. Mn valency deviations can lead to a breakdown of ferromagnetic order and thus lower the tunneling magnetoresistance of tunnel junctions. Here, at the interface, a Mn valency reduction of 0.16 ± 0.10 compared to the film interior and an additional feature at the low energy-loss flank of the Mn-L3 line have been observed. The latter may be attributed to an elongation of the (0 0 1) plane spacing at the interface detected by geometrical phase analysis of high-resolution images. Regarding the interface geometry, high-resolution high-angle annular dark-field scanning TEM images reveal an atomically sharp interface in some regions whereas the transition appears broadened in others. This can be explained by the presence of steps. The performed measurements indicate that, among the various structure-related influences on the valency, the atomic layer termination and the local oxygen content are most important.
Quantitative Cathodoluminescence Mapping with Application to a Kalgoorlie Scheelite
Authors: MacRae Colin M. , Wilson Nicholas C. , Brugger Joel
Published: May 2009

A method for the analysis of cathodoluminescence spectra is described that enables quantitative trace-element-level distributions to be mapped within minerals and materials. Cathodoluminescence intensities for a number of rare earth elements are determined by Gaussian peak fitting, and these intensities show positive correlation with independently measured concentrations down to parts per million levels. The ability to quantify cathodoluminescence spectra provides a powerful tool to determine both trace element abundances and charge state, while major elemental levels can be determined using more traditional X-ray spectrometry. To illustrate the approach, a scheelite from Kalgoorlie, Western Australia, is hyperspectrally mapped and the cathodoluminescence is calibrated against microanalyses collected using a laser ablation inductively coupled plasma mass spectrometer. Trace element maps show micron scale zoning for the rare earth elements Sm3+, Dy3+, Er3+, and Eu3+/Eu2+. The distribution of Eu2+/Eu3+ suggests that both valences of Eu have been preserved in the scheelite since its crystallization 1.63 billion years ago.
A Comparison of Macroscopic and Microscopic Hair Color Measurements and a Quantification of the Relationship between Hair Color and Thickness
Authors: Vaughn Michelle R. , Brooks Elizabeth , van Oorschot Roland A.H. , Baindur-Hudson Swati
Published: May 2009

Microscopic images of hair from 36 individuals were evaluated for color (using the CIE L*a*b* color space), hair thickness, and the pattern of pigmentation. These measurements were compared to each other and to reflective spectrophotometric measurements of macroscopic hair color. Three areas on three strands of hair were examined for each individual. Despite a large ΔE* value, there is a strong relationship between macroscopic and microscopic L* values that would be useful if one was trying to predict the color of a head of hair (macroscopic) from a strand (microscopic). A relationship between hair lightness (L*) and thickness is also found at both the macroscopic and microscopic levels. The information acquired in this study may be useful to those conducting a microscopic examination of hair, especially in forensic science, as well as those researchers investigating macroscopic hair color and hair morphology for the purposes of forensic science, anthropology, and medical science. Further investigation into objectively measuring and quantifying the microscopic color and properties of hair will assist in increasing its validity as evidence in forensic casework.
The Effect of Oxide Overlayers on Secondary Electron Dopant Mapping
Authors: Dapor Maurizio , Jepson Mark A.E. , Inkson Beverley J. , Rodenburg Cornelia
Published: May 2009

The International Technology Roadmap for Semiconductors ranks dopant profiling as one of the most difficult challenges for analysis of semiconductors. Dopant mapping in the scanning electron microscope (SEM) has the potential to provide a solution. This technique has not yet found widespread application, however, mainly due to the lack of a comprehensive theoretical model, uncertain quantification, and its inability to differentiate doping levels in n-type silicon. Although a Monte Carlo model was recently published that closely matched experimental data obtained in p-doped silicon to data obtained from the theoretical model, a large discrepancy between experimental data obtained for n-type silicon was found. Here we present a Monte Carlo model that provides close matches between experimental and calculated data in both n- and p-type silicon, paving the way for a widespread application of SEM dopant contrast.
Sediment resuspension in a shallow lake
Authors: Chung Eu Gene , Bombardelli Fabián A. , Schladow S. Geoffrey
Published: May 2009

Different mathematical formulations for the computation of the entrainment rate of sediment into suspension in lakes can produce widely disparate results under a given set of conditions, leading to problematic interpretation. In this paper, the results of a 4‐month field campaign on sediment resuspension in a large, shallow, hypereutrophic lake in southern California are presented. The field measurement program included the observation of currents and waves using a Nortek acoustic wave and current (AWAC) profiler, the observation of water temperatures using a thermistor chain, the use of optical backscatter sensors for the measurement of turbidity, a surrogate for suspended sediment concentration, and the use of meteorological data. The paper reports one of the first field experiments in lakes using the AWAC, whose signal strength has not been investigated in detail to date, and the correlation of a set of variables coming from different sources during a relatively long period of time. The contributions of different forcing mechanisms (waves, currents, and surface seiches) to the sediment resuspension in the lake are quantified, and the signal strength of the AWAC is used to address the vertical distribution of sediment in the water column. A novel relationship between the AWAC's backscatter intensity and turbidity is presented. Turbidity was found to be proportional to wK, where w is the wind speed measured at 2 m and K ranged from 4.5 to 6.5, depending on the water depth. Finally, the results of modeling the sediment entrainment into suspension in the Salton Sea are shown to be well represented by an extension of the García and Parker formula.
Explosive properties of water in volcanic and hydrothermal systems
Authors: Thiéry R. , Mercury L.
Published: May 2009

This paper describes, from a thermodynamic point of view, the physicochemical conditions, under which water behaves as an explosive. This phenomenon occurs frequently in hydrothermal and volcanic systems when water is brutally shifted from its initial equilibrium state. Water (either liquid or gas) becomes metastable or unstable and reequilibrates by violent demixing of a liquid‐gas mixture. In a first step, a phenomenological approach of metastability is given in a one‐component perspective, introducing the notion of spinodals and delimiting the extent of metastable fields. The physical mechanisms (bubble nucleation, cavitation, spinodal decomposition), which are involved in these explosive transformations of water, are detailed in what relates to the natural eruption topic. The specific thermodynamic properties (P‐v‐T‐H‐U) of metastable water are presented by using the reference Wagner and Pruss equation of state. Then, the mechanical work produced by the different possible physical transformations, including decompression, vaporization, isobaric heating, and exsolution, involved in water explosions are quantified. The classic calculation of the energy balance under the reversible assumption is extended, proposing a pathway to take irreversibility into account. This model can be used to estimate magnitude of volcanic impacts from scaling laws based on explosion energies.
A synoptic view of trends and decadal variations in autumn precipitation across the United States from 1948 to 2004
Authors: Small David , Islam Shafiqul
Published: May 2009

Precipitation and streamflow have increased in United States since 1948 with the largest increases generally observed in the Midwest and in the autumn. Autumn precipitation in the central United States also exhibits spatially correlated decadal‐scale variability with a period of approximately 12 years. In this study, we identify synoptic circulation patterns from daily atmospheric data conducive for precipitation anomalies in the central United States and link changes in the frequency of these patterns to the observed trends and decadal variations in autumn precipitation over the central United States. A synoptic air‐mass classification approach based on classification and regression trees is applied to daily NCAR‐NCEP Reanalysis data to identify synoptic circulation patterns associated with changing air‐mass characteristics and developing surface weather systems in the central United States. The advantage of the proposed approach is that precipitation data are not used to identify recurring synoptic patterns over North America. The analysis identifies four daily circulation types conducive to spatially correlated precipitation anomalies across the central United States. The frequency of these circulation types is then linked to the observed trends and decadal variations in autumn precipitation over the central United States. Our analysis suggests that the trends and decadal variations in autumn precipitation are related to an increase (decrease) in the frequency of days with a trough (ridge) over the western United States. The effect of this change in circulation on the occurrence of intense precipitation is discussed.
Accurate increment identification and the spatial extent of the common signal in five Arctica islandica chronologies from the Fladen Ground, northern North Sea
Authors: Butler Paul G. , Richardson Christopher A. , Scourse James D. , Witbaard Rob , Schöne Bernd R. , Fraser Nicole M. , Wanamaker Alan D. , Bryant Charlotte L. , Harris Ian , Robertson Iain
Published: May 2009

The creation of networks of shell‐based chronologies which can provide regionally extensive high‐resolution proxies for the marine environment depends on the spatial extent of the common environmental signal preserved in the shell banding and on the reliability of the dating model. Here Arctica islandica chronologies from five neighboring sites in the North Sea are compared, and the strength of the common environmental signal across distances up to 80 km is analyzed using statistical techniques derived from dendrochronology. The signal is found to be coherent across these distances. In a linked study, chronologies based on one of the same sites but constructed by two different research teams are compared. Methodological differences in increment interpretation are found to lead to slippage in the dating models. Systematic inclusion or exclusion of intermittently occurring increments results in the two chronologies becoming misaligned by 4 years over a 70‐year period. Comparisons with neighboring chronologies indicate that such increments can generally be regarded as genuine annual increments even if they are not visible in all shells.
Modeling overland flow and soil erosion on nonuniform hillslopes: A finite volume scheme
Authors: Heng B. C. Peter , Sander Graham C. , Scott Cecil F.
Published: May 2009

This paper presents a finite volume scheme for coupling the Saint‐Venant equations with the multiparticle size class Hairsine‐Rose soil erosion model. A well‐balanced monotone upstream‐centered schemes for conservation laws‐Hancock (MUSCL‐Hancock) method is proposed to minimize spurious waves in the solution arising from an imbalance between the flux gradient and the source terms in the momentum equation. Additional criteria for numerical stability when dealing with very shallow flows and wet/dry fronts are highlighted. Numerical tests show that the scheme performs well in terms of accuracy and robustness for both the water and sediment transport equations. The proposed scheme facilitates the application of the Hairsine‐Rose model to complex scenarios of soil erosion with concurrent interacting erosion processes over a nonuniform topography.
Sea ice variability and primary productivity in the Ross Sea, Antarctica, from methylsulphonate snow record
Authors: Rhodes Rachael H. , Bertler Nancy A. N. , Baker Joel A. , Sneed Sharon B. , Oerter Hans , Arrigo Kevin R.
Published: May 2009

The Ross Sea contains the most biologically productive continental shelf in Antarctica and is a region where the annual formation of sea ice drives substantial amounts of bottom water formation. We present snow pit chemistry data from Mt Erebus Saddle that provide a quantitative proxy to reconstruct summer sea ice conditions and rates of marine primary production. The methylsulphonate (MS) record is strongly correlated with changes in the area of open water (R2 = 0.903, p < 0.05) caused by differences in atmospheric circulation and the sea‐ice‐damming effect of large icebergs, B‐15 and C‐19, which calved from the Ross Ice Shelf in 2000 and 2002 respectively. Furthermore, MS and phytoplankton net primary production correlate significantly (R2 = 0.927, p < 0.01). Our results demonstrate the potential of the Mt Erebus Saddle ice core to reconstruct sea ice and primary productivity variability in the Ross Sea beyond the observational record.
Rapid change in freshwater content of the Arctic Ocean
Authors: McPhee M. G. , Proshutinsky A. , Morison J. H. , Steele M. , Alkire M. B.
Published: May 2009

The dramatic reduction in minimum Arctic sea ice extent in recent years has been accompanied by surprising changes in the thermohaline structure of the Arctic Ocean, with potentially important impact on convection in the North Atlantic and the meridional overturning circulation of the world ocean. Extensive aerial hydrographic surveys carried out in March–April, 2008, indicate major shifts in the amount and distribution of fresh‐water content (FWC) when compared with winter climatological values, including substantial freshening on the Pacific side of the Lomonosov Ridge. Measurements in the Canada and Makarov Basins suggest that total FWC there has increased by as much as 8,500 cubic kilometers in the area surveyed, effecting significant changes in the sea‐surface dynamic topography, with an increase of about 75% in steric level difference from the Canada to Eurasian Basins, and a major shift in both surface geostrophic currents and freshwater transport in the Beaufort Gyre.
Atomic and molecular ion dynamics during equatorial spread F
Authors: Huba J. D. , Krall J. , Joyce G.
Published: May 2009

The first simulation study of atomic and molecular ion dynamics during equatorial spread F (ESF) is presented. The simulation results are based on the Naval Research Laboratory (NRL) SAMI3/ESF three‐dimensional code. The key findings are the following: (1) a ‘super fountain’ effect can occur in the initial stage of ESF with upward ion velocities ∼1 km/s, (2) plasma depletions can be enhanced by the ‘drainage’ of H+ ions along the geomagnetic field, and (3) molecular ions (e.g., NO+) can be ‘lifted’ to high altitudes (≳400 km). We compare these results with satellite observations where applicable.
Nonequilibrium statistical mechanics of tropical sea surface temperature variability
Authors: Weiss Jeffrey B.
Published: May 2009

Climate variability has significant human impact but is difficult to model and predict. Recent theoretical developments in nonequilibrium statistical mechanics cover a class of stochastic models often used for climate phenomena. The theory for a coarse‐grained entropy production is developed for simple stochastic climate models and applied to observed tropical sea surface temperatures (SST), demonstrating that nonequilibrium properties can be quantified with climate datasets, and that tropical SST variability is approximately consistent with fluctuations about a nonequilibrium steady‐state with relatively few degrees‐of‐freedom. Fluctuations with negative entropy production demonstrate that seasonal tropical SST variability is small and fast in a thermodynamic sense, indicating that nonequilibrium fluctuation theory is applicable. This work demonstrates that nonequilibrium theory can address climate‐scale phenomena, suggests that it could provide insight into how climate change will affect climate variability, and perhaps provide a fundamental theory for variability of the climate system.
Plasma flows in the heliosheath
Authors: Richardson J. D. , Stone E. C. , Kasper J. C. , Belcher J. W. , Decker R. B.
Published: May 2009

Voyager 2 is making the first plasma measurements in the heliosheath. The radial flow speeds in the heliosheath vary between 80 and 200 km/s with an average speed of 138 km/s. The flow in the T (azimuthal) direction is fairly constant and averages about 48 km/s; the flow direction is consistent with flow away from the heliospheric nose. Flow in the N (meridional) direction is also away from the nose and averages −14 km/s. These flows suggest that the shock is blunter in the T than in the N direction, so that the heliosphere is wider than it is high. The flow in the RN plane has quasi‐periodic oscillation with a period of 110 days and an amplitude of 21 km/s. The oscillation in flow angle is about 6° in the RN plane and 17° in the TN plane and may result from periodic variations of the termination shock normal direction.
Extreme value statistics of snowfall in the Swiss Alpine region
Authors: Blanchet J. , Marty C. , Lehning M.
Published: May 2009

The mountain snow cover is an important source of water but also leads to natural hazards, such as avalanches and floods. We use data collected during winters 1999/2000 to 2007/2008 by 239 automatic and manual measurement stations in Switzerland to highlight spatial characteristics of extreme snowfall. With the help of extreme value theory based on a “peaks‐over‐threshold” approach and a Poisson point process representation, we analyze spatial patterns and correlation characteristics. Our analyses show that a significant number of stations do not follow the Gumbel distribution. In particular, low altitude stations in the Swiss Plateau are heavy tailed because of rare extraordinary snowfall events. Spatial characteristics of extreme snowfall are compared to those of the mean snowfall. Altitudinal dependence and spatial distribution of mean and extreme snowfall are similar. Both mean snowfall and extreme snowfall show an increase of magnitude between 400 and 2200 m a.s.l. and a constant or slightly decreasing magnitude at higher altitudes. Below 1200 m a.s.l., the increase with altitude is stronger because of the rain‐snow transition. Another finding is that the spatial correlation pattern of extreme snowfall is similar to that of mean snowfall, both of which are determined by the main climatological regions of Switzerland. An analysis based on those stations with a long record shows that extreme snowfall was 10% lower in the nine winters investigated than in the long‐term period, but the main spatial characteristics of the two periods show no change.
Control of genome stability by Slx protein complexes
Authors: Rouse John
Published: May 2009

The six Saccharomyces cerevisiae SLX genes were identified in a screen for factors required for the viability of cells lacking Sgs1, a member of the RecQ helicase family involved in processing stalled replisomes and in the maintenance of genome stability. The six SLX gene products form three distinct heterodimeric complexes, and all three have catalytic activity. Slx3–Slx2 (also known as Mus81–Mms4) and Slx1–Slx4 are both heterodimeric endonucleases with a marked specificity for branched replication fork-like DNA species, whereas Slx5–Slx8 is a SUMO (small ubiquitin-related modifier)-targeted E3 ubiquitin ligase. All three complexes play important, but distinct, roles in different aspects of the cellular response to DNA damage and perturbed DNA replication. Slx4 interacts physically not only with Slx1, but also with Rad1–Rad10 [XPF (xeroderma pigmentosum complementation group F)–ERCC1 (excision repair cross-complementing 1) in humans], another structure-specific endonuclease that participates in the repair of UV-induced DNA damage and in a subpathway of recombinational DNA DSB (double-strand break) repair. Curiously, Slx4 is essential for repair of DSBs by Rad1–Rad10, but is not required for repair of UV damage. Slx4 also promotes cellular resistance to DNA-alkylating agents that block the progression of replisomes during DNA replication, by facilitating the error-free mode of lesion bypass. This does not require Slx1 or Rad1–Rad10, and so Slx4 has several distinct roles in protecting genome stability. In the present article, I provide an overview of our current understanding of the cellular roles of the Slx proteins, paying particular attention to the advances that have been made in understanding the cellular roles of Slx4. In particular, protein–protein interactions and underlying molecular mechanisms are discussed and I draw attention to the many questions that have yet to be answered.
PCNA on the crossroad of cancer
Authors: Stoimenov Ivaylo , Helleday Thomas
Published: May 2009

Cancer is caused by genetic changes that often arise following failure to accurately replicate the DNA. PCNA (proliferating-cell nuclear antigen) forms a ring around the DNA to facilitate and control DNA replication. Emerging evidence suggests that PCNA is at the very heart of many essential cellular processes, such as DNA replication, repair of DNA damage, chromatin structure maintenance, chromosome segregation and cell-cycle progression. Progression of the DNA replication forks can be blocked by DNA lesions, formed either by endogenous damage or by exogenous agents, for instance anticancer drugs. Cellular response often results in change of PCNA function triggered either by specific post-translational modification of PCNA (i.e. ubiquitylation) or by exchange of its interaction partners. This puts PCNA in a central position in determining the fate of the replication fork. In the present article, we review PCNA modifications and interaction partners, and how those influence the course of events at replication forks, which ultimately determines both tumour progression as well as the outcome of anticancer treatment.