bluuebunny/crossref_metadata_2025 huggingface dataset:
Primer development for the plastid region ycf1 in Annonaceae and other magnoliids
Authors: Neubig Kurt M. , Abbott J. Richard
Published: June 2010

• Premise of the study: Primers were developed for a portion of the ycf1 plastid gene in magnoliid taxa to investigate the utility of ycf1 in phylogenetic analyses.

• Methods and Results: Twenty‐six species across six families within the magnoliid group (Canellales, Piperales, Laurales, and Magnoliales) were sampled to examine the ability to amplify ycf1. Additionally, 29 accessions of Asimina and Deeringothamnus (Annonaceae) were sequenced to assess levels of variation in ycf1 compared to matK and trnL‐F.

• Conclusions: Results indicate that ycf1 is easily amplified and sequenced. In Annonaceae, ycf1 provides more informative phylogenetic characters than commonly used markers such as matK and trnL‐F.
Altered Expression of TNF-α Signaling Pathway Proteins in Systemic Lupus Erythematosus
Authors: ZHU LANG-JING , LANDOLT-MARTICORENA CAROLINA , LI TIMOTHY , YANG XIAO , YU XUE-QING , GLADMAN DAFNA D. , UROWITZ MURRAY B. , FORTIN PAUL R. , WITHER JOAN E.
Published: June 2010

Objective.

To investigate the expression of tumor necrosis factor receptors (TNFR1 and TNFR2) and adapter proteins (TRADD, RIP, and TRAF2) in peripheral blood mononuclear cell (PBMC) subsets from patients with systemic lupus erythematosus (SLE).

Methods.

PBMC were isolated from 45 SLE patients and 25 controls, and stained with labeled antibodies that enabled identification of various T cell, B cell, and monocyte subpopulations. Expression of TNF-related signaling molecules was measured by staining with labeled antibodies either directly or following fixation and permeabilization. Apoptosis was quantified using an anti-active caspase 3 antibody. RNA expression of TNF-related signaling molecules was assessed by quantitative RT-PCR and serum levels of TNF-α by ELISA.

Results.

SLE patients had increased levels of TNFR1, TNFR2, and TRAF2, together with decreased levels of RIP, on various B, CD4+ T, and CD8+ T cell subsets as compared to controls. This altered expression was seen in both naive and memory subpopulations, and reflected altered staining of the whole population rather than a subset of cells that were activated. The levels of these molecules were not significantly correlated with serum TNF-α levels or their RNA expression in whole peripheral blood. TNFR1 and TNFR2 expression was negatively correlated with disease activity. There was no association between the proportion of apoptotic cells in any of the subpopulations and serum TNF-α levels or expression of TNF-related signaling molecules.

Conclusion.

Patients with SLE had altered expression of TNF-related signaling molecules, suggesting that there may be an imbalance in TNF-α signaling favoring cellular activation as opposed to proapoptotic pathways.
Femoroacetabular Impingement Syndrome: An Underrecognized Cause of Hip Pain and Premature Osteoarthritis?
Authors: REID GRAHAM D. , REID CALLUM G. , WIDMER NADIA , MUNK PETER L.
Published: June 2010

Acetabular dysplasia is well recognized as a potential predisposing factor to the development of hip osteoarthritis (OA). In the orthopedic literature, other dysmorphic and orientation abnormalities of the femoral head, femoral head-neck junction, and the acetabulum have been reported, with increasing frequency in recent years, under the term femoroacetabular impingement syndrome (FAI). The studies have shown a clear association of these structural anomalies with patients’ symptoms and signs, radiographic and pathologic abnormalities, and the development of degenerative hip arthritis. FAI is now believed to be a very important predisposing factor for the development of degenerative hip arthritis, particularly in younger adults. Although the results of longterm studies are awaited, the hope is that early surgical intervention in patients with FAI will change the course or prevent the development of hip OA. It is well documented that early recognition of potential FAI surgical candidates, before OA is advanced, determines the postsurgical outcome. FAI has not been reported in the rheumatology literature, but since patients with FAI likely often initially present to rheumatology clinics for assessment of hip pain, it is important for rheumatologists to be aware of this condition and refer to orthopedics when appropriate. The objective of this review is to provide an outline of the basic concepts of FAI, including clinical presentation and radiographic findings, so that rheumatologists become more familiar with this important emerging entity.
Endothelial Progenitor Cells in Mixed Cryoglobulinemia
Authors: MARCHI FRANCESCO , CHIMENTI DANIELE , TAVONI ANTONIO , DELLA ROSSA ALESSANDRA , BOMBARDIERI STEFANO , MIGLIORINI PAOLA
Published: June 2010

Objective.

Endothelial progenitor cells (EPC) are a rare population of circulating cells involved in vascular homeostasis. Our aim was to analyze EPC in patients with mixed cryoglobulinemia (MC).

Methods.

EPC were evaluated by cytometry according to guidelines of the International Society for Hematotherapy and Graft Engineering in 17 patients with MC and 36 controls.

Results.

Numbers of EPC were significantly increased in MC compared to controls and correlated with cryocrit, but not with clinical manifestations of the disease.

Conclusion.

The high number of EPC might indicate an intact vascular repair ability. Alternatively, EPC might be defective in homing ability and their increase may represent the attempt to restore vascular integrity.
Une vision de l'Europe
Authors: Didelon Clarisse
Published: June 2010

Le processus l’élargissement de l’Union européenne pose la question de la définition de l’Europe et de ses limites et surtout de ses représentations. Cet article présente la méthodologie et les résultats d’une enquête portant sur la représentation de l’Europe de chercheurs et responsables politiques dans le domaine de l’aménagement du territoire européen impliqués dans le programme ESPON. Son objectif n’est pas, en tant que tel, de proposer une limite de l’Europe mais de présenter une vision de l’Europe d’un groupe spécifique et de chercher à l’expliquer. Cette enquête montre que la définition scolaire traditionnelle de l’Europe joue un rôle important dans la perception de l’Europe, mais aussi que la proximité spatiale joue en faveur de l’élargissement.
Insécurité alimentaire et production illicite d'opium en Asie
Authors: Chouvy Pierre-Arnaud
Published: June 2010

La production illicite d’opium en Asie a longtemps bénéficié des synergies qui existaient entre économie de guerre et économie des drogues illicites. Que ce soit en Birmanie, en transition entre guerre et paix, ou en Afghanistan, où l’insécurité va croissant depuis 2005, la production illicite d’opium n’apparaît plus comme étant motivée par le financement des parties en conflit mais plutôt par l’insuffisance et l’insécurité alimentaires auxquelles les populations doivent faire face. En effet, en dépit des grandes différences qui existent entre les contextes afghan, birman et laotien de production d’opium, les études menées lors des années 2000 montrent que ce sont l’insuffisance et l’insécurité alimentaires qui expliquent en grande partie le recours à la production illicite d’opium. En fin de compte, la production illicite d’opium doit moins son succès à sa rentabilité, qui est faible, qu’au fait qu’elle permet de dépasser en partie certaines des limites structurelles et conjoncturelles des systèmes de production agricoles concernés.
La nourriture et la faim dans Cyrano de Bergerac d'Edmond Rostand
Authors: Bourgeois Jean
Published: June 2010

Loin de constituer un objet d’étude marginal dans une pièce qui exalte tant l’héroïsme, le thème de la nourriture et de la faim se révèle fondamental dans Cyrano de Bergerac . Ce leitmotiv structure l’œuvre. La nourriture est associée à l’amour, ce qui introduit un clivage entre les personnages : ceux qui mangent n’aiment pas, ceux qui aiment ne mangent pas. Mais le lien, plus inattendu, que la nourriture entretient également avec la poésie produit un effet comique, à moins qu’il ne trahisse un regard ironique porté par l’auteur sur la littérature. Il apparaît finalement que tout Cyrano de Bergerac repose sur le dualisme du corps et de l’esprit, c’est le grand thème qui donne à la pièce sa cohérence profonde.
Paul Claudel : deux pièces pour enfants
Authors: Moraly Yehuda
Published: June 2010

Deux pièces mineures, une farce pour marionnettes et une pièce de patronage, écrites par Claudel pendant la première guerre mondiale indiquent ce que pourrait être, selon lui, un nouveau théâtre sacré. Dans L’ours et la lune (1917), le rôle du théâtre est de montrer la manière dont le mal n’est qu’une étape du Bien. La folie du monde n’est qu’apparente. Dans La Nuit de Noël  1914 (1915) le réel est montré comme un alphabet grâce auquel nous pouvons comprendre l’Au-delà. Le théâtre est un outil de connaissance par lequel nous pouvons accéder à la compréhension de l’infini.
Les Faux-monnayeurs, roman « touffe », ou le dépassement de l'antinomie décadence/classicisme
Authors: Wittmann Jean-Michel
Published: June 2010

Édouard dans Les Faux-Monnayeurs et Gide lui-même dans son Journal des Faux-Monnayeurs ne cessent de désigner le roman en cours d’écriture comme une « touffe » appelée à grandir et à proliférer. Cette métaphore prend tout son sens dans le contexte d’un jeu d’allusions à des textes antérieurs, de Barrès, de Maurras et, surtout, de Bourget. Gide propose en effet une réflexion critique sur la « Théorie de la décadence » proposée en 1881 par ce dernier. Ce débat qui engage des enjeux esthétiques mais aussi éthiques et même, proprement politiques, lui permet de clore le débat sur la question du classicisme, en redéfinissant du même coup la fonction de la littérature, en rupture avec l’idéal de l’écrivain responsable naguère défendu par Bourget.
Conduire ou séduire la raison ?
Authors: Ebbersmeyer Sabrina
Published: June 2010

L ’ article analyse l ’ influence des émotions et de la rhétorique dans le raisonnement pratique. Suivant Aristote, on souligne ici le rôle essentiel des émotions dans les décisions et les actions, mais il est extrêmement ambivalent. La première partie (I.) présente la relation problématique entre la philosophie et le raisonnement rationnel d ’ une part et la rhétorique et les émotions de l ’ autre. Ensuite on analysera les arguments d ’ Aristote dans sa Rhétorique contre (II.) et pour (III.) l ’ excitation des émotions dans les discours politiques. La dernière partie (IV.) suggère deux éléments de discussion : comment et pourquoi la conception aristotélicienne des émotions pourrait-elle apporter une contribution dans le débat contemporain sur les émotions ? Car, d ’ une part, celui-ci est marqué par l ’ approche cognitiviste qui néglige la dimension sociale des émotions. D ’ autre part, la thèse aristotélicienne remet en question notre conception d ’animal rationale et engage une nouvelle appréciation de la composante émotionnelle de la nature humaine.
Discours, langage et totalité (Hegel et Saussure)
Authors: Brafman Jacques
Published: June 2010

Partant d ’ un commentaire de quelques lignes de la Préface à la Phénoménologie de l’esprit ou au Système de la Science de Hegel 1 , que nous mettrons en perspective avec des extraits et des notes du Cours de linguistique générale de Saussure, nous voudrions montrer que : 1. La philosophie est un Discours écrit ou un Livre sui-réflexif et/ou systématique, soit un Méta -discours ; aussi répond-elle à l ’ essence du Langage qui ne se signifie jamais que soi-même. 2. Puisqu ’ il se fonde sur ce dernier, comme lui, le discours-livre philosophique ne laisse rien en dehors de soi et parle de, ou plutôt du, tout ; en quoi il s ’ avère effectivement universel. 3. Tous les autres discours, scientifiques, moraux, artistiques, religieux, s ’ y enracinant, inutile de s ’ interroger sur un impensé ou un sens qui échapperait au discursif. La vérité (philosophique) se confond ainsi avec le procès linguistique dont elle partage et la prémisse  – être c ’ est être dit –  et la conclusion  –  on n ’ a rien dit , tant que l ’ on n ’ a pas tout dit. Elle en forme en quelque sorte l’Auto - Réflexion explicite, achevée et/ou cohérente. Si les philosophies préhégéliennes ont bien tendu vers cela, il appartenait au Système hégélien d ’ en tirer toutes les conséquences et d ’ accomplir ce que celles-là ont seulement esquissé. Quant au système de philosophie du langage de Saussure, il en reformulera techniquement les principes.
Les «géographies» de l'art: physionomies, races et mythes dans la peinture «ethnographique»
Authors: Peltre Christine
Published: June 2010

Résumé Comme le sculpteur Charles Cordier, à qui fut en 2004 consacrée une exposition au Musée d’Orsay, Théodore Valerio (1819-1879) appartient à une génération d’artistes qui a tenté, par sa description des races, de faire œuvre anthropologique. L’occasion lui en a été fournie par des voyages en Europe centrale entre 1851 et 1854 dont il a rapporté aquarelles et dessins ainsi qu’un texte publié en 1858 dans L’artiste, intitulé «Essais ethnographiques sur les populations hongroises». La démarche de Valerio s’inscrit dans le contexte de la recherche géographique de la «physionomie», à laquelle l’encourage le savant Alexandre de Humboldt. Par la technique et par l’esprit, ces portefeuilles ethnographiques, présentés à l’Exposition universelle de 1855, se rattachent aux systèmes raciologiques contemporains. Ils sont cependant aussi inspirés par des enjeux esthétiques et par la quête identitaire des artistes au xix e siècle, associant volontiers leur « race» à celle de l’autre, ailleurs.
À la frontière des «races»: la géographie morale de Maurice Barrès
Authors: Al-Matary Sarah
Published: June 2010

Résumé En marge des journaux et des Cahiers , l’espace romanesque offre au nationalisme barrésien la possibilité d’une idéalisation du discours racial. Le paysage, subjectivé, permet la réalisation d’un double projet poétique et idéologique: la recréation d’une Lorraine rêvée, fière guerrière latine résistant à l’envahisseur germain. Le conflit franco-allemand de la fin du siècle est alors présenté comme un avatar de la lutte séculaire entre la Civilisation et la Barbarie. Mais Barrès, loin de reprendre le modèle darwinien prisé par l’adversaire, choisit de racialiser le paysage, afin de poser la supériorité spirituelle et «morale» des vaincus.
Tardi : dessiner, illustrer
Authors: Chimot Jean-Philippe
Published: June 2010

Résumé Auteur de bandes dessinées (littérature dessinée), Tardi est également illustrateur, notamment de romans de Louis-Ferdinand Céline. La présente étude vise à faire apparaître les différences de régime et de rapport texte-image dans certaines BD, selon les époques et selon les collaborations, pour mieux s’intéresser à la réussite (souplesse, finesse, dynamisme, stimulation du lecteur) qu’atteint le mode élaboré par Tardi, de dissémination et de fonctionnalité des images inventées et placées dans un texte intégral de Céline ( Voyage au bout de la nuit ).
Tardi et la Commune de 1871 à travers Le Cri du peuple : roman graphique ou histoire graphique ?
Authors: Fournier Éric
Published: June 2010

Résumé Peut-on relire Le Cri du peuple , récit fictionnel, comme un essai d’histoire graphique ? Bien que n’oubliant pas son empathie libertaire avec la Commune, Tardi, s’appuyant sur une forte maîtrise des sources, œuvre aussi en historien du sensible, restituant ainsi les représentations, les pratiques, et les paysages de Paris en 1871 avec talent et fidélité aux événements. Son trait spécifique rend avec beaucoup d’efficacité les paroxysmes de la « semaine sanglante ». Cette œuvre invite ainsi à s’interroger sur les différentes modalités d’écriture de l’histoire : Tardi associe ici de façon probante la modernité de la bande dessinée avec les codes du récit historique propre au premier xix e  siècle.
La guerre lancinante dans l'œuvre de Jacques Tardi
Authors: Branland Marine
Published: June 2010

Résumé Partant du constat d’une présence obsédante de la Grande Guerre dans les bandes dessinées de Jacques Tardi, cet article revient sur la genèse de son œuvre afin de mettre en évidence les imbrications initiales entre sujet et médium d’expression et de mieux comprendre les enjeux de cette création. De ses premiers travaux à Putain de guerre ! (2008-2009), la Première Guerre mondiale – véritable objet de réflexion – s’est imposée et transformée sous son crayon et sa plume, véhiculant une histoire du conflit qui oscille entre récit documentaire et reconstruction imaginaire, élaborée à partir de son histoire familiale et de son orientation idéologique libertaire.
Un paysage à la gloire de l'Homme. La représentation de l'environnement préhistorique dans l'enseignement et la fiction de la seconde moitié du xxe siècle
Authors: Semonsut Pascal
Published: June 2010

Résumé À partir de l’étude de manuels scolaires, de films, de bandes dessinées et de romans, cet article se propose de décrire l’image donnée de l’environnement préhistorique dans la seconde moitié du xx e  siècle, une image difficile à peindre et cela pour deux raisons : d’une part, elle change selon la décennie et le média envisagés ; d’autre part, c’est une image brouillée parce que traversée de messages antagonistes. Malgré ces filtres, aux mieux déformants, au pire opaques, cette image est assez univoque et son message est clair. L’environnement préhistorique représente une menace constante. Devant nos ancêtres préhistoriques, il dresse une multitude d’obstacles L’objectif d’une telle représentation est clair : montrer la force irrésistible de l’Homme et sa supériorité incontestable.
Sharing Information about the Pain
Authors: Chalfen Richard , Rich Michael
Published: June 2010

The chapter presents findings from recent studies that feature a model of doctor-patient collaboration called Video Intervention/Prevention Assessment (VIA), a research methodology that engages patient-participants in sharing their life stories on video, communicating their concerns and teaching their doctors what it means to live with a chronic illness. Patients are collaborators in creating a comprehensive understanding of illness that expands the medical community’s definition of disease. This chapter focuses on visual narratives made by young patients with Cystic Fibrosis and Spina Bifida as they experience their transitions from pediatric to adult-oriented medicine care. Collaboration in research facilitates more effective ownership of and accountability for their illness, facilitating adherence to treatment plans and improved quality of life. Our chapter concludes with an evaluation of the pros and cons of VIA as a collaborative information methodology.
Dose-modified lenalidomide induces sustained hematological response in patients with intermediate to high risk myelodysplasia
Authors: Khalafallah Alhossain A. , Fernandopulle Bernadene , Brain Terry
Published: June 2010

No Abstract Available
The theological responses to the socio-economic activities that undermine water as a resource
Authors: Resane Thomas
Published: June 2010

This article focuses, from a theological perspective, on both the ecological crisis and the politico-economic dealings in relation to water – especially with regard to the unsound ways in which governments deal with this resource. Texts are read from an anthropogenic perspective, as opposed to an anthropocentric one. Such a reading scenario calls for responses from theology with regard to the human position in creation. Humans are not a grand master plan of creation, but the completion and fulfilment of it, given an enormous sense of responsibility for the earth. The article argues that the human–earth relation should be understood from the point of responsibility based on solidarity, interdependency and stewardship. Theologians are challenged to embrace eco-ethics.
Parametric approximation of surface clusters driven by isotropic and anisotropic surface energies
Authors: Barrett John W. , Garcke Harald , Nürnberg Robert
Published: June 2010

We present a variational formulation for the evolution of surface clusters in

ℝ^3

by mean curvature ﬂow, surface diffusion and their anisotropic variants. We introduce the triple junction line conditions that are induced by the considered gradient ﬂows, and present weak formulations of these ﬂows. In addition, we consider the case where a subset of the boundaries of these clusters are constrained to lie on an external boundary. These formulations lead to unconditionally stable, fully discrete, parametric ﬁnite element approximations. The resulting schemes have very good properties with respect to the distribution of mesh points and, if applicable, volume conservation. This is demonstrated by several numerical experiments, including isotropic double, triple and quadruple bubbles, as well as clusters evolving under anisotropic mean curvature ﬂow and anisotropic surface diffusion, including computations for regularized crystalline surface energy densities.
Random paths with bounded local time
Authors: Benjamini Itai , Berestycki Nathanaël
Published: June 2010

We consider one-dimensional Brownian motion conditioned (in a suitable sense) to have a local time at every point and at every moment bounded by some ﬁxed constant. Our main result shows that a phenomenon of entropic repulsion occurs: that is, this process is ballistic and has an asymptotic velocity approximately 4.58. . . as high as required by the conditioning (the exact value of this constant involves the ﬁrst zero of a Bessel function). We also study the random walk case and show that the process is asymptotically ballistic but with an unknown speed.
Extremals for the Sobolev inequality on the seven-dimensional quaternionic Heisenberg group and the quaternionic contact Yamabe problem
Authors: Ivanov Stefan , Minchev Ivan , Vassilev Dimiter
Published: June 2010

A complete solution to the quaternionic contact Yamabe problem on the seven dimensional sphere is given. Extremals for the Sobolev inequality on the seven dimensional Heisenberg group are explicitly described and the best constant in the
L2
Folland–Stein embedding theorem is determined.
Attitudes, Knowledge, and Practices Regarding Malaria Prevention and Treatment among Pregnant Women in Eastern India
Authors: Sabin Lora L. , Rizal Abanish , Brooks Mohamad I. , Singh Mrigendra P. , Tuchman Jordan , Wylie Blair J. , Joyce Katherine M. , Yeboah-Antwi Kojo , Singh Neeru , Hamer Davidson H.
Published: June 2010

We explored views toward and use of malaria prevention and treatment measures among pregnant women in Jharkhand, India. We conducted 32 in-depth interviews and six focus group discussions (total = 73 respondents) with pregnant women in urban, semi-urban, and rural locations in a region with moderate intensity malaria transmission. Most respondents ranked malaria as an important health issue affecting pregnant women, had partially correct understanding of malaria transmission and prevention, and reported using potentially effective prevention methods, usually untreated bed nets. However, most conveyed misinformation and described using unproven prevention and/or treatment methods. Many described using different ineffective traditional malaria remedies. The majority also showed willingness to try new prevention methods and take medications if doctor-prescribed. Misconceptions and use of unproven prevention and treatment methods are common among pregnant women in eastern India. Policy makers should focus on improving knowledge and availability of effective malaria control strategies in this population.
Asymptomatic Dengue Infection in a Cuban Population Confirms the Protective Role of the RR Variant of the FcγRIIa Polymorphism
Authors: García Gissel , Sierra Beatriz , Pérez Ana B. , Aguirre Eglys , Rosado Ileana , Gonzalez Narjara , Izquierdo Alienys , Pupo Maritza , Danay Díaz Didye Ruiz , Sánchez Lizet , Marcheco Beatriz , Hirayama Kenji , Guzmán María G.
Published: June 2010

The role of human Fcγ receptors (FcγR) has been recognized considerably over the last years. These receptors vary in their affinity for IgG subclasses and the intracellular signals elicited by them. Allelic variants of FcγR genes may influence the biological phagocyte activity, accounting for an inherited pre-disposition to disease. The specific FcγRIIa (CD32) contains a polymorphic variant (H/R131) that has been associated to a reduced risk for developing dengue hemorrhagic fever (DHF). Here, we investigated the role of this polymorphism in a very well-characterized group of Cuban individuals with antecedents of DHF, dengue fever (DF), or subclinical dengue infection. The HH131 genotype was significantly associated with dengue disease, either DF (*P = 0.016; odds ratio = 4.425; 95% confidence interval = 1.10–20.52) or DHF (P = 0.00018; odds ratio = 10.56; 95% confidence interval = 2.33–54.64) with respect to the subclinical infection.
Bioavailability of particle‐associated silver, cadmium, and zinc to the estuarine amphipod Leptocheirus plumulosus through dietary ingestion
Authors: Schlekat Christian E. , Decho Alan W. , Chandler G. Thomas
Published: June 2010

We conducted experiments to determine effects of particle type on assimilatory metal bioavailability to Leptocheirus plumulosus, an infaunal, estuarine amphipod that is commonly used in sediment toxicity tests. The following particles were used to represent natural food items encountered by this surface‐deposit and suspension‐feeding amphipod: bacterial exopolymeric sediment coatings, polymeric coatings made from Spartina alterniflora extract, amorphous iron oxide coatings, the diatom Phaeodactylum tricornutum, the chlorophyte Dunaliella tertiolecta, processed estuarine sediment, and fresh estuarine sediment. Bioavailability of the gamma‐emitting radioisotopes 110mAg, 109Cd, and 65Zn was measured as the efficiency with which L. plumulosus assimilated metals from particles using pulse‐chase methods. Ag and Cd assimilation efficiencies were highest from bacterial exopolymeric coatings. Zn assimilation efficiency exhibited considerable interexperimental variation; the highest Zn assimilation efficiencies were measured from phytoplankton and processed sediment. In general, Ag and Cd assimilation efficiencies from phytoplankton were low and not related to the proportion of metal associated with cell cytosol or cytoplasm, a phenomenon reported for other particle‐ingesting invertebrates. Amphipod digestive processes explain differences in Ag and Cd assimilation efficiencies between exopolymeric coatings and phytoplankton. Results highlight the importance of labile polymeric organic carbon sediment coatings in dietary metals uptake by this benthic invertebrate, rather than recalcitrant organic carbon, mineralogical features such as iron oxides, or phytoplankton.
Photochemical oxygen consumption in marine waters: A major sink for colored dissolved organic matter?
Authors: Andrews Steven S. , Caron Sigalit , Zafiriou Oliver C.
Published: June 2010

Quantification of photochemical O2 uptake provides a measure of total chemical photooxidation of dissolved organic matter (DOM). Here we study this process and present estimates suggesting that photooxidation has the potential to significantly modify marine DOM pools, complementing or exceeding oxidation via coupled chemical‐biological pathways. We measured apparent quantum yields (AQYs) of photobleaching, O2 uptake, and H2O2 production in several coastal marine samples and in dilutions of a tropical estuarine water with oligotrophic seawater. O2‐loss AQYs varied little among samples or with dilution but decreased linearly from 1.2×10–3 at 300 nm to 0.3×10–3 at 400 nm and dropped about threefold to near‐constant values with increasing absorbed light dose. H2O2 production, about 45% of O2 uptake, showed similar dependencies, whereas singlet oxygen (O2 (1Δg)) reactions contributed less than 1% of O2 uptake for typical coastal water. Implications of these findings for photochemical O2, H2O2, and DOM cycling are discussed.

Modeling the dose‐dependence of O2 loss and photobleaching at 310 nm required three DOM pools. In the simplest case, about 90% is a weakly absorbing, low‐AQY pool of DOM admixed with two similar‐sized pools of more photochemically reactive DOM. This result suggests that rigorously extrapolating laboratory data to the environment requires detailed mapping of dose‐wavelength‐photobleaching AQY surfaces.

Action spectra and DOM flux estimates for coastal photooxidative chemistry were derived. Site‐specific potential rates are comparable to available in situ data. Globally, the DOM photolysis capacity appears to be larger than estimated coastal DOM inputs, especially in tropical and temperate areas, including areas with maximal DOM inputs.
Organic carbon fluxes, degradation, and accumulation in an anoxic basin: Sediment trap results from the Cariaco Basin
Authors: Thunell Robert C. , Varela Ramon , Llano Martin , Collister James , -Karger Frank Muller , Bohrer Richard
Published: June 2010

Organic carbon fluxes were measured in the anoxic water column of the Cariaco Basin under varying levels of primary productivity. Our results indicate that water column degradation of fresh organic matter in this anoxic setting is similar to what has been previously observed in the open ocean. Additionally, the rate at which carbon is consumed increases as primary productivity increases. These findings support the hypothesis that sulfate reduction is as efficient as aerobic respiration in degrading labile organic matter and that an anoxic water column does not necessarily result in an enhanced delivery of organic carbon to the sea floor. We estimate that 1–2% of the organic carbon produced at the surface reaches the seafloor and that approximately 50% of this is preserved in the sediments. This burial efficiency is comparable to that previously reported for both oxic and anoxic settings, and with sedimentation rates similar to that in Cariaco Basin.
The role of extracellular carbonic anhydrase activity in inorganic carbon utilization of Phaeocystis globosa (Prymnesiophyceae): A comparison with other marine algae using the isotopic disequilibrium technique
Authors: Elzenga J. Theo M. , Prins Hidde B. A. , Stefels Jacqueline
Published: June 2010

The utilization of inorganic carbon species by the marine microalga Phaeocystis globosa (Prymnesiophyceae) and several other algal species from different taxa, was investigated by determining the time course of 14C incorporation in isotopic disequilibrium experiments. From these kinetic data, conclusions can be drawn about the carbon species, CO2 or HCO3−, that is being utilized. By comparing the uptake kinetics in the absence and presence of acetazolamide (AZ) or dextran‐bound sulfonamide, inhibitors of external carbonic anhydrase (CA), it was determined that P. globosa, Dunaliella tertiolecta, and some strains of Emiliania huxleyi do use HCO3− by extracellular, A‐catalyzed conversion to CO2, which then diffuses across the membrane. Nannochloropsis, Thalassiosira pseudonanna, and often Synechococcus use HCO3− without extracellular conversion. Thalasiosira punctigera, some strains of E. huxleyi, and Rhodomonas sp. use exclusively free CO2. The presence of extracellular CA activity in Phaeocystis is not constitutive but is induced under low inorganic carbon conditions. Thus, marine microalgae show variability in carbon acquisition strategy for one single species, depending on external conditions, and in carbon acquisition strategy between species. Determining AZ‐induced changes in carbon uptake kinetics provides a sensitive test for the presence of extracellular CA activity. With the potentiometric method, no CA activity could be measured, whereas with the isotopic disequilibrium technique, significant CA activity could be detected.
Diel feeding behavior of meiofauna and their relationships with microalgal resources
Authors: Buffan‐Dubau Evelyne , Carman Kevin R.
Published: June 2010

Diel variation of feeding by ostracods and harpacticoid copepod species on microalgae was examined in a mudflat of a Spartina alterniflora saltmarsh. Feeding (gut pigments and consumption of 14C‐labeled algae) and benthic microalgal abundance and composition (HPLC analysis of photopigments) were measured every 6 h over a 48‐h period. Midday feeding peaks were detected in Coullana sp. juveniles and adult females (but not males), Microarthridion littorale, Pseudostenhelia wellsi, and ostracods and were coincident with peaks in microalgal biomass. This pattern of midday feeding peaks by meiofauna differs from classical models of zooplankton feeding, which typically peak at night. Midday feeding peaks were apparently influenced by functional responses to food availability (ostracods and Coullana sp. females and juveniles), entrained diel rhythms (M. littorale), influence of light—positive (M.littorale) or negative (Coullana sp.), and possibly by vertical migration of diatoms within sediment. The negative influence of light on grazing by Coullana sp. may have implications for its feeding activity during midday low tides. Diatoms dominated the benthic microalgae, but cyanobacteria and chlorophytes contributed significantly to the planktonic community. Coullana sp. gut pigments indicate that at least part of its diet is planktonic, but it selectively avoids planktonic cyanobacteria. Diel variation of microalgal biomass appears to be influenced by meiofaunal grazing, which implies that meiofauna represent an important link between microalgal primary production and higher trophic levels.
The complete genomic sequence of the marine phage Roseophage SIO1 shares homology with nonmarine phages
Authors: Rohwer Forest , Segall Anca , Steward Griegx , Seguritan Victor , Breitbart Mya , Wolven Felise , Farooq Azam Farooqx
Published: June 2010

Viruses are ubiquitous components of the marine environment, frequently reaching concentrations of 107–108 viruses per milliliter of surface seawater. The majority of these viral particles are bacteriophages (phages). Although the oceans are probably the largest pool of bacteriophages on the planet, the evolutionary relationships of marine phages to phages from other environments are unknown. To address this issue, we have completely sequenced the genome of the lytic marine phage, Roseophage SIO1, that infects the heterotrophic marine bacterium Roseobacter SIO67. This phage has an isometric capsid with a diameter of approximately 43 nm, a short tail, a buoyant density of 1.49 g cm‐3 in CsCl, and a 39,906‐bp dsDNA genome. Sequence similarities and relative positions within the genome suggest that three of the open reading frames (ORFs) are homologous to the primase, DNA polymerase, and endodeoxyribonuclease I proteins of coliphages T3 and T7. The results are consistent with the mosaic theory of phage evolution and indicate a genetic link between marine and nonmarine phages. Additionally, basic life histories of marine phages can be elucidated by comparison of complete genomes to those of other extensively studied phages (e.g., lambda, T4, T7). The DNA replication machinery of Roseophage SIO1 shows a clear homology with that of coliphages T3 and T7, suggesting that the process of DNA replication may be similar among these phages. The Roseophage SIO1 genome also encodes four predicted proteins involved in phosphate metabolism (RP PhoH, RP ribonucleotide reductase, RP Thy1, and RP endodeoxyribonuclease I) suggesting that phosphate recycling is important to Roseophage SIO1's life cycle. Other interesting clues about Roseophage SIO's life history come from the absence of certain expected protein regions. For example, we have not been able to identify the Roseophage SIO1 structural proteins (e.g., capsid proteins) by homology to other phages. It is also conspicuous that the Roseo‐phage SIO1 genome lacks a recognizable RNA polymerase, an essential component of T3 and T7 life cycles. Analysis of the Roseophage SIO1 genome shows that marine and nonmarine phages are genetically related but basic life histories may be significantly different.
Colonization of marine snow aggregates by invertebrate zooplankton: Abundance, scaling, and possible role
Authors: KiØrboe Thomas
Published: June 2010

I compiled literature observations of abundances of invertebrate zooplankters associated with marine snow aggregates in the euphotic zone. Abundances, normalized with ambient concentrations of colonizers, scale with equivalent aggregate radius raised to power 2.27. Different taxonomic groups showed different affinities for aggregates and copepods and crustacean nauplii were the dominant groups on aggregates. The encounter volumes (volume searched to find one aggregate) are substantial, e.g., >1 liter for a 1‐cm aggregate, suggesting that some zooplankters actively search for aggregates. The scaling of the enrichment of invertebrates in aggregates over ambient water with aggregate radius (r) was significantly different from that of bacteria, —r−0.73 and _r−2.25, respectively, and for aggregates larger than 0.1 cm radius, invertebrates were one to several orders of magnitude more enriched than bacteria. Tentative estimates of the remineralization and degradation rates of aggregates due to the activity of invertebrate colonizers suggest that aggregate carbon is turned over within one to a few days. This is similar to or faster than turnover rates due to microorganisms. It is also estimated that between 20 and 70% of aggregate carbon is degraded by invertebrate colonizers before a sinking aggregate leaves a 50‐ m‐deep euphotic zone. Thus, the majority of aggregated material may be degraded within the euphotic zone due to the combined activity of colonizing invertebrates, other grazers, and microorganisms.
Production of extracellular Cu complexing ligands by eucaryotic phytoplankton in response to Cu stress
Authors: Croot Peter L. , Moffett James W. , Brand Larry E.
Published: June 2010

Organic chelators that are thought to be of recent biological origin control copper speciation in seawater. Previous studies have often resolved these copper binding ligands into two classes, class 1 ligands (conditional stability constants 1012 –1014 M−1) and class 2 ligands (conditional stability constants 109–1012 M−1). At present the sources and structures of these chelators are unknown. Previous work has shown that in response to copper toxicity, cultures of the marine cyanobacteria Synechococcus spp. produce a strong ligand, similar in binding strength to class 1 ligands. We extended this work by surveying a suite of copper‐stressed marine eucaryotic phytoplankton for the production of copper binding ligands. Most eucaryotic species we studied did not produce ligands with the binding strength of class 1 ligands, but many produced class 2 ligands. A marine dinoflagellate Amphidinium carterae was found to produce very strong ligands; however, the low abundance of dinoflagellates in the open ocean may mean that this source of class 1 ligands is more important in coastal waters. This survey shows that there are many biological sources of copper binding ligands, but that procaryotes such as cyanobacteria are more plausible sources of class 1 ligands in the open ocean than eucaryotes.
The random redistribution of sediment by wind in a lake
Authors: Douglas Richard W. , Rippey Brian
Published: June 2010

The total sedimentation rate was measured fortnightly for a year in a large shallow lake (Lough Neagh, Northern Ireland, surface area 383 km2, mean depth 8.9 m) at five sites using 10 sediment traps. The total sedimentation rate included both primary and secondary sedimentation. As the annual average total sedimentation rate, 53.2 ± 44.1 g m−2 d−1, is more than 25 times the primary value, secondary sedimentation due to wind‐induced resuspension is very important. The average of the largest 30% of wave mixed layer (WML) values, a function of wind speed and effective fetch, strongly correlates with the total sedimentation rate (r2 values of 0.69 and 0.98 at two westerly sites) at most of the sites. As the WML value approaches the water depth, then the orbital motion of the waves and the associated turbulence cause sediment disturbance and resuspension. Changing WML values, then, provide a basis to describe the "random redistribution" (RR) of sediment in lakes and these resuspension events can occur as frequently as 2–3 times every two weeks. This study provides, for the first time, clear results and a description of the process of RR of sediment in a lake, particularly the link between wind and sediment resuspension.
Conditional density dependence: The flow trigger to expression of density‐dependent emigration in bay scallops
Authors: Powers Sean P. , Peterson Charles H.
Published: June 2010

Understanding how biological interactions vary under different water flow regimes is important in systems that are known to exhibit fluctuations in flow due to storms, tidal forcing, or variation in habitat structure. We performed a series of experiments to determine the migratory response of bay scallops, Argopecten irradians concentricus Say, to changes in intraspecific density under two different, tidally oscillating flow regimes in the field: 0–0.10 m s−1 and 0–0.28 m s−1. Despite the bay scallop's ability to swim actively and achieve unaided bursts of motion covering distances on the scale of 0.5 m, the expression of density‐dependent emigration was dependent on the presence of higher flows. In the low‐flow regime, there was negligible emigration during 24 h at any density level (12, 25, or 62 m−2); however, emigration rate increased with density (0% at 12 m−2, 60% at 25 m−2, and 71% at 62 m−2) under the higher flow regime. These results demonstrate that flow can facilitate biological interactions, creating conditional density dependence.
Total phosphorus–chlorophyll a size fraction relationships in southern Québec lakes
Authors: Masson Stéphane , Pinel‐Alloul Bernadette , Smith Val H.
Published: June 2010

The study is a first attempt to generate a series of Total Phosphorus–Chlorophyll a (TP–Chl a) predictiveOC models relating the quantitative responses of four algal size fractions to phosphorus gradients. The study was carried out in 27 glacial lakes from two regions in southern Quebec, the Laurentians and the Eastern Townships, and covered a relatively modest range of trophic conditions (TP, 3–34 µg P L‐1; Chl a, 0.3–7.6 µg L−1). Algal biomass was estimated using measurements of Chl a, and the total Chl a was divided into four operational size fractions: picophytoplankton <3 mm, nanophytoplankton 3–20 mm, nanophytoplankton plus picophytoplankton <20 mm (edible fraction), and microphyto‐plankton >20 mm (inedible fraction). We tested the hypothesis that the slopes of the TP–Chl a regression models developed for algal size fractions would increase consistently from the smallest to the largest algal size fraction, as suggested by the first half of the sigmoidal TP–Chl a models. Although there was no consistent trend in the magnitudes of the slopes of TP–Chl a relationships for picophytoplankton (slope = 1.14), nanophytoplankton (0.93), and microphytoplankton (1.22), Chl a concentrations in the largest size fraction increased more rapidly with phosphorus enrichment than in either of the smaller fractions. When included as an additional variable, lake water alkalinity improved the prediction of Chl a and presented differential effects on size fractions. The effect of TP enrichment on microphytoplankton is more pronounced in well‐buffered lakes, whereas TP enrichment has a stronger effect on nanophytoplankton in low‐alkalinity lakes. The effects of alkalinity may be the result of either a pH influence on phytoplankton carbon uptake or a stronger top‐down grazing effect on small algae in well‐buffered lakes.
Nitrate regulation of Fe reduction and transport by Fe‐limited Thalassiosira oceanica
Authors: Maldonado Maria T. , Price Neil M.
Published: June 2010

Under Fe‐limiting conditions, nitrate (NO3−)‐grown marine diatoms have higher intracellular Fe requirements, but divide as fast or faster than ammonium (NH4+)‐grown cells by maintaining faster steady‐state Fe uptake rates. Here we report that Thalassiosira oceanica, clone 1003, possesses an Fe reductase that reduces Fe(III) bound to a variety of organic ligands, including the siderophore desferrioxamine B (DFB), a high affinity, Fe(III)‐specific ligand. Reduction is mediated extracellularly and is induced by Fe deficiency. Cellular rates of Fe(III) reduction are significantly faster in NO3− ‐ than in NH4+ ‐grown cultures suggesting a link with N metabolism. At subsaturating Fe concentrations, short‐ and long‐term Fe uptake rates are also significantly faster in NO3− ‐ than in NH4+ ‐grown cells. The results suggest that when Fe is limiting, faster rates of reduction of organically bound Fe(III) by phyto‐plankton promote faster rates of Fe transport and growth. The implications of these findings could be significant for understanding phytoplankton Fe nutrition in oceanic waters where organic complexation dominates the speciation of Fe. We hypothesize that the reductive Fe transport pathway may enable phytoplankton to directly utilize Fe bound to strong organic ligands in the sea.
Some considerations of the 210Pb constant rate of supply (CRS) dating model
Authors: Sanchez‐Cabeza J. A. , Ani‐Ragolta I. , Masquè P.
Published: June 2010

One of the most widely used radionuclides in the study of recent sedimentation processes is 210Pb. Its depth profile in sediments is used as input for various dating models, which provide chronologies, mass fluxes, and sedimentation rates. In this work we revisited the CRS (constant rate of supply) model, widely used for dating sediments through 210Pb. A more general hypothesis (periodic flux [PF]) was proposed and, although it confirmed the validity of CRS chronology, a detailed analysis of the mass sedimentation formula pointed out an inconsistency of the cited model. A new mass sedimentation formula was proposed and validated with a lake sediment core and four marine sediment cores.
Direct and indirect effects of juvenile Buenoa macrotibialis (Hemiptera: Notonectidae) on the zooplankton of a shallow pond
Authors: Hampton Stephanie E. , Gilbert John J. , Burns Carolyn W.
Published: June 2010

We investigated the effects of juvenile Buenoa macrotibialis on the small bodied (<500 mm) zooplankton assemblage with which it naturally occurs. By monitoring 37–46‐liter enclosures with and without Buenoa over 9–12 d, we found that second and fourth instar Buenoa caused large declines in the copepod Tropocyclops extensus and the rotifer Hexarthra mira. Additionally, populations of several small rotifers increased in the presence of fourth instar Buenoa, probably because of release from Tropocyclops predation, competition, or both.