bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding and recollection of the risks associated with cesarean delivery during the consent process
Authors: Odumosu Modupe , Pathak Sonu , Barnet‐Lamb Eleanor , Akin‐Deko Olayinka , Joshi Vaishali , Selo‐Ojeme Dan
Published: May 2012

Objective

To investigate women's recall of information provided during the consent process for cesarean delivery, specifically the associated risks, 24 hours after the procedure.

Methods

A prospective questionnaire‐based study was conducted at the Barnet and Chase Farm Hospitals NHS Trust between May 2009 and August 2010. Women who had undergone a cesarean delivery (planned or emergency) completed a self‐administered questionnaire 24 hours after delivery. Women who did not recall the risks associated with the procedure (group 1) were compared with those who did recall this information (group 2).

Results

A total of 554 women participated in the study. Group 1 (n = 140) were 4 times more likely to have undergone an emergency cesarean than group 2 (n = 414) (OR 4; 95% CI, 2.5–6.2). Group 2 were more to likely to have higher than secondary level education, 7 times more likely to have understood the explanation of the procedure (OR 6.9; 95% CI, 3.3–14.2), and 9 times more likely to recall that the risks had been explained (OR 9.4; 95% CI, 5.2–17.1). More women in group 1 reported that they would have liked to receive an information leaflet about cesarean delivery at the first prenatal visit.

Conclusion

One in 4 women did not recall any risks associated with cesarean delivery shortly after the procedure and this group of women were less likely to understand or recall the details of the consent discussion.
Spatial reconstruction of semi-quantitative precipitation fields over Africa during the nineteenth century from documentary evidence and gauge data
Authors: Nicholson Sharon E. , Klotter Douglas , Dezfuli Amin K.
Published: May 2012

The article presents a newly created precipitation data set for the African continent and describes the methodology used in its creation. It is based on a combination of proxy data and rain gauge records. The data set is semi-quantitative, with a “wetness” index of − 3 to + 3 to describe the quality of the rainy season. It covers the period AD 1801 to 1900 and includes data for 90 geographical regions of the continent. The results underscore a multi-decadal period of aridity early in the nineteenth century.
Isobath variation and trapping of continental shelf waves
Authors: Kaoullas G. , Johnson E. R.
Published: May 2012

Since Trösch (Proceedings of the 4th International Conference on Applied Numerical Modeling, Tainan, Taiwan, 1984 (ed. H. M. Hsia, Y. L. Chou, S. Y. Wang & S. J. Hsieh) Science and Technology Series, vol. 63, 1986, pp. 307–311. American Astronautical Society) found trapped sub-inertial oscillations in computations of low-frequency variability in the Lake of Lugano, models of trapping have generally considered evenly spaced isobaths parallel to shorelines with approximate boundary conditions at any shelf–ocean boundary. Here an asymptotic analysis for slowly varying topography and accurate spectral computations demonstrate trapping on non-rectilinear shelves. It is shown that changes in any of three factors, isobath curvature, distance from the coast and the shelf-break, and the slope at the shelf-break, are sufficient on their own to give trapping. Continental shelves that abut smoothly onto the open ocean are considered thus avoiding the shelf–ocean boundary condition approximation and allowing the accuracy of previous approximations to be assessed.
Effects of heat-inactivatedLactobacillus gasseriTMC0356 on metabolic characteristics and immunity of rats with the metabolic syndrome
Authors: Shi Lei , Li Ming , Miyazawa Kenji , Li Yun , Hiramatsu Masaru , Xu Jiayu , Gong Cai , Jing Xiaofan , He Fang , Huang Chengyu
Published: May 2012

The present study investigated the potential health-promoting effects of heat-inactivatedLactobacillus gasseriTMC0356 (TMC0356) on the metabolic syndrome (MS) and the probable mechanisms underlying these effects using an MS rat model. For the purpose of the study, sixty Sprague–Dawley rats were randomly divided into five groups: a control group fed a conventional diet, an MS model group fed a high-fat and high-salt (HFS) diet and three TMC0356 test groups (low-, medium- and high-dose groups) fed an HFS diet supplemented with TMC0356 at 41·8, 83·5 and 167·0 mg/kg body weight (BW) per d, respectively. Food intake and BW were measured weekly. Fasting blood glucose (FBG), lipid profiles and blood pressure (BP) were measured at 0, 5, 10 and 15 weeks. Organ coefficients, immune cell counts and serum insulin, adiponectin, C-reactive protein (CRP), IL-6, TNF-α, IgG and secretory IgA levels were measured at the 15th week after diet intervention. The HFS diet increased the BW, liver or fat:BW ratio, FBG, homeostatic model assessment of insulin resistance, adiponectin, serum LDL-cholesterol and total cholesterol levels and BP (P< 0·01). Average food and energy intakes in the three TMC0356 groups were significantly lower than those of the MS model group. All the metabolic indices, except BP, were markedly improved (P< 0·05) by oral administration of low and medium doses of TMC0356. The thymus index in the medium-dose group and lymphocyte, CRP, IL-6, TNF-α and IgG levels in all the three TMC0356 groups were significantly increased (P< 0·05 orP< 0·01) compared with those in the MS model group. These results suggest that TMC0356 can improve the metabolic characteristics of MS rats by suppressing appetite. Additionally, the enhancement of inflammatory immune response may be, at least in part, the mechanism underlying the health-promoting effects of TMC0356 on the MS.
High-fat diet feeding induces a depot-dependent response on the pro-inflammatory state and mitochondrial function of gonadal white adipose tissue
Authors: Amengual-Cladera E. , Lladó I. , Proenza A. M. , Gianotti M.
Published: May 2012

Obesity has been related to a chronic pro-inflammatory state affecting white adipose tissue (WAT), which has a great impact on carbohydrate, lipid and energy metabolism. In turn, the dysregulation of adipokine secretion derived from the accumulation of excess lipids in adipocytes further contributes to the development of insulin resistance and can be associated with mitochondrial dysfunction. The aim of the present study was to determine whether sexual dimorphism found in the systemic insulin sensitivity profile is related to sex differences in a high-fat diet (HFD) response of gonadal WAT at mitochondrial function and inflammatory profile levels. Wistar rats (10 weeks old) of both sexes were fed a control pelleted diet (3 % (w/w) fat;n8 for each sex) or a HFD (24 % (w/w) fat;n8 for each sex). Serum insulin sensitivity markers, mRNA expression levels of inflammatory factors and the protein content of insulin and adiponectin signalling pathways were analysed, as well as the levels of the main markers of mitochondrial biogenesis, antioxidant defence and oxidative damage. In the present study, the periovarian depot exhibits a greater expandability capacity, along with a lower hypoxic and pro-inflammatory state, without signs of mitochondrial dysfunction or changes in its dynamics. In contrast, epididymal fat has a much more pronounced pro-inflammatory, hypoxic and insulin-resistant profile accompanied by changes in mitochondrial dynamics, probably associated with HFD-induced mitochondrial dysfunction. Thus, this explains the worse serum insulin sensitivity profile of male rats.
Effects of abomasal infusion of flaxseed (Linum usitatissimum) oil on microbial β-glucuronidase activity and concentration of the mammalian lignan enterolactone in ruminal fluid, plasma, urine and milk of dairy cows
Authors: Côrtes Cristiano , da Silva-Kazama Daniele , Kazama Ricardo , Benchaar Chaouki , dos Santos Geraldo , Zeoula Lucia M. , Gagnon N. , Petit Hélène V.
Published: May 2012

Ruminal microbiota plays an important role in the conversion of plant lignans into mammalian lignans. The main mammalian lignan present in the milk of dairy cows fed flax products is enterolactone (EL). The objectives of the present study were to investigate the effects of abomasal infusion of flax oil on the metabolism of flax lignans and concentrations of EL in biological fluids of dairy cows. A total of six rumen-cannulated dairy cows were assigned within a 2 × 3 factorial arrangement of six treatments utilising flax hulls (0 and 15·9 % of DM) and abomasal infusion of flax oil (0, 250 and 500 g/d). There were six periods of 21 d each. Samples were collected during the last 7 d of each period and subjected to chemical analysis. Flax hull supplementation increased concentrations of EL in ruminal fluid, plasma, urine and milk, while flax oil infusion had no effect. Post-feeding, β-glucuronidase activity in the ruminal fluid of cows infused with 250 g flax oil was significantly lower for cows fed hulls than for those fed the control diet. The present study demonstrated that the presence of a rich source of n-3 fatty acids such as flax oil in the small intestine does not interfere with the absorption of the mammalian lignan EL and that lower ruminal β-glucuronidase activity had no effect on the conversion of flax lignans into EL in the rumen of dairy cows.
Sharing the Burden of the Border: Layered Security Co-operation and the Canada–US Frontier
Authors: von Hlatky Stéfanie , Trisko Jessica N.
Published: May 2012

Abstract.Effectively managing the Canada–US border has emerged as a major security challenge post-9/11. Burden-sharing theories suggest that the United States would take the lead on border security due to its hegemonic role in ensuring North American security, while smaller nations such as Canada enjoy a free ride. We refute the free-rider hypothesis and propose an approach which accounts for the differentiated concerns held by contiguous states. By dedicating sizeable resources to the issue of border security and by appealing to advantageous negotiation strategies, Ottawa has leveraged its position as a secondary state vis-à-vis the United States. Efforts employed by the province of Quebec have bolstered Canada's relative influence in this issue area. We argue that Quebec and Ottawa perceived and acted on complementary interests which empowered the Canadian government to respond more forcefully to US-driven border security measures after 9/11. We conclude with alternative models to border security management, as well the practical implications of our argument.

Résumé.Un des défis majeurs depuis le 11 septembre 2001 concerne la gestion de la frontière entre le Canada et les États-Unis. Les théories sur le partage du fardeau supposent que les États-Unis sont l'acteur dominant dans l'élaboration des politiques frontalières, assurant la sécurité du continent nord-américain. En contrepartie, les états secondaires, comme le Canada, se voient souvent attribuer le rôle du passager clandestin dans ces interactions. Cet article porte sur le partage du fardeau entre le Canada et les États-Unis en ce qui a trait à la sécurité frontalière. Nous réfutons l'hypothèse du passager clandestin en proposant une approche qui prend compte des préoccupations distinctes des deux états voisins. En investissant d'importantes ressources pour la gestion de la frontière et en appliquant des stratégies de négociations avantageuses, Ottawa a su surmonter son statut de puissance moyenne face aux États-Unis. Le Québec a contribué au renforcement de la position canadienne en agissant de concert avec Ottawa, puisque les deux paliers poursuivaient des intérêts complémentaires. Le résultat de cette coopération est une riposte cohérente et soutenue démontrée par le gouvernement canadien face aux mesures de sécurité initiées par les États-Unis après le 11 septembre. Enfin, nous discutons également des implications pratiques de notre argument en comparant les différents modèles dans la litérature portant sur la gestion de la sécurité frontalière.
La raison d'État constitutionnelle
Authors: Simard Augustin
Published: May 2012

ResuméCet article examine la façon dont les constitutionnalistes allemands ont cherché à tirer leçon de l'échec de la République de Weimar, ainsi que le rôle de repoussoir que cette référence traumatique a joué dans la mise en place d'une compréhension «robuste» et «défensive» de la démocratie libérale dès les années 1930. À partir des réflexions de quelques juristes émigrés aux États-Unis, il distingue trois programmes concurrents : celui de l'antiextrémisme, qui trouve son origine dans l'antipositivisme weimarien; celui de la «démocratie militante» (Karl Loewenstein); et celui de la «dictature constitutionnelle» (Carl J. Friedrich). Au sein de chacun, la confrontation avec Carl Schmitt revêt une importance décisive, en dépit de son caractère parfois implicite et médiatisé. Éclairer ces échanges permet de juger dans quelle mesure les régimes démocratiques post-1945 ont intégré les idées de Schmitt.

AbstractThis paper explores the lessons drawn by German constitutional scholars from the breakdown of the Weimar Republic, and how this traumatic experience became a starting point at the end of the 1930s for a new conception of democracy both liberal and robust (or “defensive”). Emigré constitutional scholars devised three distinctive versions of this “democratic robustness”: an “anti-extremist” (which originated in Weimar legal antipositivism); a “militant democracy” (first exposed by Karl Loewenstein); and a “constitutional dictatorship” (Carl J. Friedrich, Frederick W. Watkins). At the heart of each one lies a decisive debate with Carl Schmitt, even if implicit or diffracted. By reconstructing these debates one can appreciate to what extent postwar constitutional democracies have incorporated Schmitt's ideas.
Non-planar Gardner double layers in two-ion-temperature dusty plasma
Authors: ASADUZZAMAN M. , MAMUN A. A.
Published: May 2012

Non-planar (cylindrical and spherical) double layers (DLs) in two-ion-temperature dusty plasma, whose constituents are inertial negative dust, ions with two distinctive temperatures, and Boltzmann electrons, are studied by employing the reductive perturbation method. The modified Gardner equation describing the nonlinear propagation of dust-acoustic (DA) waves is derived, and its non-planar double layer solutions are analyzed numerically. The parametric regimes for the existence of DA DLs, which are found to be associated with positive potential only, are obtained. The basic features of non-planar DA DLs, which are found to be different from planar ones, are also identified. The implications of our results to different space and laboratory dusty plasma situations are discussed.
Proteomics at the schistosome-mammalian host interface: any prospects for diagnostics or vaccines?
Authors: WILSON R. ALAN
Published: May 2012

Since 2004 there has been a remarkable increment in our knowledge of the proteins and glycans that reside at, or are released from the surfaces of schistosomes in the mammalian host. Initial characterization of the soluble proteome permits distinctions to be made between the parasite secretome and its necrotome. The principal proteins secreted by the cercaria to gain access to the skin have been described as well as those released by migrating schistosomula. An inventory of transporters, enzymes and structural proteins has been shown to reside the tegument surface, but also immunoglobulins, complement factors and host CD44. The secreted membranocalyx that overlies the plasma membrane may contain a small number of proteins, not simply acting as physical barrier, but its lipid composition remains elusive. Analysis of worm vomitus has provided insights into blood feeding, increasing the number of known lysosomal hydrolases, and identifying a series of carrier proteins potentially involved in uptake of lipids and inorganic ions by the gut epithelium. The egg secretions that aid escape from the tissues include a mixture of MEG-2 and MEG-3 family variant proteins. The utility of identified proteins for the development of new diagnostics, and their potential as vaccines candidates is evaluated.
Tomatidine promotes the inhibition of 24-alkylated sterol biosynthesis and mitochondrial dysfunction in Leishmania amazonensis promastigotes
Authors: MEDINA J. M. , RODRIGUES J. C. F. , DE SOUZA W. , ATELLA G. C. , BARRABIN H.
Published: May 2012

Leishmaniasis is a set of clinically distinct infectious diseases caused by Leishmania, a genus of flagellated protozoan parasites, that affects ∼12 million people worldwide, with ∼2 million new infections annually. Plants are known to produce substances to defend themselves against pathogens and predators. In the genus Lycopersicon, which includes the tomato, L. esculentum, the main antimicrobial compound is the steroidal glycoalkaloid α-tomatine. The loss of the saccharide side-chain of tomatine yields the aglycone tomatidine. In the present study, we investigated the effects of tomatidine on the growth, mitochondrial membrane potential, sterol metabolism, and ultrastructure of Leishmania amazonensis promastigotes. Tomatidine (0·1 to 5 μM) inhibited parasite growth in a dose-dependent manner (IC50=124±59 nM). Transmission electron microscopy revealed lesions in the mitochondrial ultrastructure and the presence of large vacuoles and lipid storage bodies in the cytoplasm. These structural changes in the mitochondria were accompanied by an effective loss of mitochondrial membrane potential and a decrease in ATP levels. An analysis of the neutral lipid content revealed a large depletion of endogenous 24-alkylated sterols such as 24-methylene-cholesta-5, 7-dien-3β-ol (5-dehydroepisterol), with a concomitant accumulation of cholesta-8, 24-dien-3β-ol (zymosterol), which implied a perturbation in the cellular lipid content. These results are consistent with an inhibition of 24-sterol methyltransferase, an important enzyme responsible for the methylation of sterols at the 24 position, which is an essential step in the production of ergosterol and other 24-methyl sterols.
Epidemiology of Brazilian spotted fever in the Atlantic Forest, state of São Paulo, Brazil
Authors: OGRZEWALSKA MARIA , SARAIVA DANILO G. , MORAES-FILHO JONAS , MARTINS THIAGO F. , COSTA FRANCISCO B. , PINTER ADRIANO , LABRUNA MARCELO B.
Published: May 2012

The tick-borne bacteriumRickettsia rickettsiiis the aetiological agent of Brazilian spotted fever (BSF). The present study evaluated tick infestations on wild and domestic animals, and the rickettsial infection in these animals and their ticks in 7 forest areas adjacent to human communities in the São Paulo Metropolitan Area (SPMA). The results were compared to ecological traits of each sampled area. Two main tick species,Amblyomma aureolatumandRhipicephalus sanguineus,were collected from dogs. The major ticks found on small mammals and birds wereIxodes loricatusandAmblyomma longirostre, respectively. Both anti-R. rickettsiiantibodies andR. rickettsii-infected ticks were detected on dogs from only 2 areas in the southern part of the SPMA, which were considered to be endemic for BSF; the remaining 5 areas were considered to be non-endemic. Ecologically, the BSF-endemic areas clearly differed from the non-endemic areas by the presence of significantly more degraded forest patches in the former. The present results corroborate historical observations that have indicated that all human cases of BSF in the SPMA were contracted in the southern part of this metropolitan area. However, not all forest patches in the southern part of the SPMA were shown to be associated with BSF endemism.
Robert Pinker, the Idea of Welfare and the Study of Social Policy: On Unitarism and Pluralism
Authors: OFFER JOHN
Published: May 2012

This article reappraises the distinction upon which Robert Pinker has insisted since the 1970s between the heuristic and the normative dimensions of concepts and theories associated with ‘welfare’ in social policy studies, a distinction prompted by, for instance, the writings of Richard Titmuss. It discusses Pinker's differentiation of forms of study which seek to account for the likenesses and unlikenesses within and between the welfare systems of different countries from forms of study aiming to establish moral criteria by which one system of welfare can be deemed superior to another. In particular, it highlights his emphasis on the need for social policy as a subject to attend to: (a) the reality of everyday ideas of social welfare and ‘faring well’ in general; (b) how everyday ideas of ‘faring well’ are exhibited in what he has called ‘conditional altruism’, whether exercised within families, towards strangers or across nations; (c) the practices undertaken by individuals and families to attain freedom and security as well as to meet those of their needs commonly taken within social policy studies to be the components of ‘welfare’; (d) the difficulties, moral, political, social and economic, associated with Titmussian welfare unitarism, in contrast to welfare pluralism. The article thus provides a review of aspects of Pinker's many published papers as well as his influentialSocial Theory and Social PolicyandThe Idea of Welfare.
Speedups of ergodic group extensions
Authors: BABICHEV ANDREY , BURTON ROBERT M. , FIELDSTEEL ADAM
Published: May 2012

We prove that for all ergodic extensions $S_{1}$ of a transformation by a locally compact second countable group $G$, and for all $G$-extensions $ S_{2} $ of an aperiodic transformation, there is a relative speedup of $ S_{1} $ that is relatively isomorphic to $S_{2}$. We apply this result to give necessary and sufficient conditions for two ergodic $n$-point or countable extensions to be related in this way.
Dynamic assessment of language disabilities
Authors: Martin Deirdre
Published: May 2012

The paper reports a study of a narrative-based Dynamic Assessment (DA) procedure developed in the USA that is used in the UK with children with developmental language disabilities. Three monolingual English children with language disabilities are assessed by a speech/language pathologist/therapist who is learning to work with DA in collaboration with the researcher in the study. Quantitative evidence of language structures indicates that the children learn to talk more after two intervention sessions. Evidence from the mediations of the children's language learning capabilities throws diagnostic light on the nature of their needs. A critique is offered of the assessment tool, and conclusions are drawn about the implications of DA for differentiating language-learning potential in language disabilities, with suggestions for further study.
A NEW PANEL DATA TREATMENT FOR HETEROGENEITY IN TIME TRENDS
Authors: Kneip Alois , Sickles Robin C. , Song Wonho
Published: May 2012

This paper introduces a new estimation method for arbitrary temporal heterogeneity in panel data models. The paper provides a semiparametric method for estimating general patterns of cross-sectional specific time trends. The methods proposed in the paper are related to principal component analysis and estimate the time-varying trend effects using a small number of common functions calculated from the data. An important application for the new estimator is in the estimation of time-varying technical efficiency considered in the stochastic frontier literature. Finite sample performance of the estimators is examined via Monte Carlo simulations. We apply our methods to the analysis of productivity trends in the U.S. banking industry.
MODELING NONLINEAR AND HETEROGENEOUS DYNAMIC LINKS IN INTERNATIONAL MONETARY MARKETS
Authors: Arouri Mohamed El Hedi , Jawadi Fredj , Nguyen Duc Khuong
Published: May 2012

We use daily short-term interbank interest rates of France, the United Kingdom, and the United States to examine the dynamic links of international monetary markets from 2004 to 2009. Results from vector error-correction models and smooth-transition error-correction models show strong evidence of nonlinear and heterogeneous causalities between the three interest rates. We also find that changes in the U.S. interest rate deviations from the long-run equilibrium led those in France and in the United Kingdom by one to two days. Finally, the national interest rate nexus appears to converge in nonlinear fashion toward a steady state because it is subject to structural change beyond a certain rate threshold. Our findings have important implications for the actions of leading central banks (ECB, Bank of England, and U.S. Fed) because the joint behavior of short-term interest rates can be viewed as an indicator of the degree of central banks' policy interdependence.
Studies of Japanese Society and Culture: Sociology and Cognate Disciplines in Hong Kong
Authors: CHU YIN-WAH
Published: May 2012

This paper reviews the studies of Japanese society and culture undertaken by Hong Kong-based sociologists and scholars in related disciplines. It presents information on research projects funded by the Research Grants Council, Social Sciences Citation Index (SSCI), and Arts and Humanities Citation Index (A&HCI) journal articles, authored and edited books, book chapters, non-SSCI and non-A&HCI journal articles, as well as master and doctoral theses written by scholars and graduate students associated with Hong Kong's major universities. It is found that the main topics of research are Japan's capitalist development and corporate growth, meanings and social ramifications of traditional and popular culture, education, gender, and marriage, as well as aspects of work and employment, whereas the major research methods include document analysis, ethnography, and in-depth interviews. The limited amount of research and the preoccupation with economic development and popular culture reflect in part Hong Kong's unique political conditions and the government's indifference to the pursuit of social and political policy analysis. In recent years, the growth of academic exchanges between scholars in Hong Kong, Japan, and other East Asian regions and the heightened emphasis by university administrators on academic research will hopefully bring about advancements in such academic endeavors.
NICE's social value judgements about equity in health and health care
Authors: Shah Koonal K. , Cookson Richard , Culyer Anthony J. , Littlejohns Peter
Published: May 2012

The National Institute for Health and Clinical Excellence (NICE) routinely publishes details of the evidence and reasoning underpinning its recommendations, including its social value judgements (SVJs). To date, however, NICE's SVJs relating to equity in the distribution of health and health care have been less specific and systematic than those relating to cost-effectiveness in the pursuit of improved total population health. NICE takes a pragmatic, case-based approach to developing its principles of SVJ, drawing on the cumulative experience of its advisory bodies in making decisions that command respect among its broad range of stakeholders. This paper aims to describe the SVJs about equity in health and health care that NICE has hitherto used to guide its decision making. To do this, we review both the general SVJs reported in NICE guidance on methodology and the case-specific SVJs reported in NICE guidance about particular health care technologies and public health interventions.
Access to primary care in Hong Kong, Greater London and New York City
Authors: Chau Pui Hing , Woo Jean , Gusmano Michael K. , Weisz Daniel , Rodwin Victor G. , Chan Kam Che
Published: May 2012

We investigate avoidable hospital conditions (AHC) in three world cities as a way to assess access to primary care. Residents of Hong Kong are healthier than their counterparts in Greater London or New York City. In contrast to their counterparts in New York City, residents of both Greater London and Hong Kong face no financial barriers to an extensive public hospital system. We compare residence-based hospital discharge rates for AHC, by age cohorts, in these cities and find that New York City has higher rates than Hong Kong and Greater London. Hong Kong has the lowest hospital discharge rates for AHC among the population 15–64, but its rates are nearly as high as those in New York City among the population 65 and over. Our findings suggest that in contrast to Greater London, older residents in Hong Kong and New York face significant barriers in accessing primary care. In all three cities, people living in lower socioeconomic status neighborhoods are more likely to be hospitalized for an AHC, but neighborhood inequalities are greater in Hong Kong and New York than in Greater London.
New evidence for the origin of the Porcupine Median Volcanic Ridge: Early Cretaceous volcanism in the Porcupine Basin, Atlantic margin of Ireland
Authors: Calvès Gérôme , Torvela Taija , Huuse Mads , Dinkleman Menno G.
Published: May 2012

Two‐dimensional pre‐stack depth migrated seismic reflection data, gravity and velocity models are used to assess the nature and origin of a prominent, buried ridge, the Porcupine Median Volcanic Ridge (PMVR) within the Porcupine Basin, offshore Ireland. The debate on the origin of the PMVR during the past 30 years has followed the evolution of the concept of continental margin genesis. In this paper, the origin of the ridge is evaluated on the basis of the internal geometry and velocity structure, revealed by the seismic data. Implication of the presence of these type of ridges in hyper‐extensional rifted margins is discussed and compared with other margins. The analysis indicates that the ridge is an extrusive volcanic ridge, probably tholeiitic in composition, constructed by stacked hyaloclastite deltas and topped by carbonate platforms. The results invalidate previously proposed models involving highly rotated fault blocks and the serpentinite mud volcanism. The extension magnitude analysis suggests a highly stretched setting where limited mantle serpentinization may have occurred, but the architecture and velocity of the PMVR demonstrates that it is made of lower velocity materials than serpentinite. During the opening of the North Atlantic, the PMVR represents the northern time‐equivalent magmatic event expressed along the Newfoundland‐Iberia‐Galicia, recorded by the J anomaly that originate from Cretaceous volcanic deposits.
Inferring interplanetary magnetic field polarities from geomagnetic variations
Authors: Vokhmyanin M. V. , Ponyavin D. I.
Published: May 2012

In this paper, we propose a modified procedure to infer the interplanetary magnetic field (IMF) polarities from geomagnetic observations. It allows to identify the polarity back to 1905. As previous techniques it is based on the well‐known Svalgaard‐Mansurov effect. We have improved the quality and accuracy of polarity inference compared with the previous results of Svalgaard (1975) and Vennerstroem et al. (2001) by adding new geomagnetic stations and extracting carefully diurnal curve. The data demonstrates an excess of one of the two IMF sectors within equinoxes (Rosenberg‐Coleman rule) evidencing polar field reversals at least for the last eight solar cycles. We also found a predominance of the two‐sector structure in late of descending phase of solar cycle 16.
Slow shock formation and structure with sub‐Alfvénic shear flow in magnetic reconnection
Authors: Li L. J. , Zhang X. , Wang L. C. , Ma Z. W.
Published: May 2012

Slow shock formation and structure associated with magnetic reconnection are investigated in the presence of sub‐Alfvénic shear flow using a compressible resistive MHD model. It is found for the first time that one or two pairs of the slow shocks are formed in the inflow region away from the reconnection separatrices within compressible resistive MHD. The distributions of the slow shocks depend largely on the plasma beta and the shear flow velocity that lead to the increase of magnetic reconnection rate. One pair of the slow shocks is formed for β = 0.2 and two pairs of the slow shocks are generated for β = 1.0 with the shear flow velocity in the range 0.6 VA to 0.9 VA. For high plasma beta (β = 5.0), there is no slow shock formed outside the reconnection separatrices. The results can be applied to interpret slow shock observations at the dayside magnetopause.
Anatomy of the high‐frequency ambient seismic wave field at the TCDP borehole
Authors: Hillers G. , Campillo M. , Lin Y.‐Y. , Ma K.‐F. , Roux P.
Published: May 2012

The Taiwan Chelungpu‐fault Drilling Project (TCDP) installed a vertical seismic array between 950 and 1270 m depth in an active thrust fault environment. In this paper we analyze continuous noise records of the TCDP array between 1 and 16 Hz. We apply multiple array processing and noise correlation techniques to study the noise source process, properties of the propagation medium, and the ambient seismic wave field. Diurnal amplitude and slowness patterns suggest that noise is generated by cultural activity. The vicinity of the recording site to the excitation region, indicated by a narrow azimuthal distribution of propagation directions, leads to a predominant ballistic propagation regime. This is evident from the compatibility of the data with an incident plane wave model, polarized direct arrivals of noise correlation functions, and the asymmetric arrival shape. Evidence for contributions from scattering comes from equilibrated earthquake coda energy ratios, the frequency dependent randomization of propagation directions, and the existence of correlation coda waves. We conclude that the ballistic and scattered propagation regime coexist, where the first regime dominates the records, but the second is weaker yet not negligible. Consequently, the wave field is not equipartitioned. Correlation signal‐to‐noise ratios indicate a frequency dependent noise intensity. Iterations of the correlation procedure enhance the signature of the scattered regime. Discrepancies between phase velocities estimated from correlation functions and in‐situ measurements are associated with the array geometry and its relative orientation to the predominant energy flux. The stability of correlation functions suggests their applicability in future monitoring efforts.
Modeling the growth of stylolites in sedimentary rocks
Authors: Rolland Alexandra , Toussaint Renaud , Baud Patrick , Schmittbuhl Jean , Conil Nathalie , Koehn Daniel , Renard François , Gratier Jean‐Pierre
Published: May 2012

Stylolites are ubiquitous pressure solution seams found in sedimentary rocks. Their morphology is shown to follow two self‐affine regimes. Analyzing the scaling properties of their height over their average direction shows that (1) at small scale, they are self‐affine surfaces with a Hurst exponent around 1, and (2) at large scale, they follow another self‐affine scaling with Hurst exponent around 0.5. In the present paper, we show theoretically the influence of the main principal stress and the local geometry of the stylolitic interface on the dissolution reaction rate. We compute how it is affected by the deviation between the principal stress axis and the local interface between the rock and the soft material in the stylolite. The free energy entering in the dissolution reaction kinetics is expressed from the surface energy term and via integration from the stress perturbations due to these local misalignments. The resulting model shows the interface evolution at different stress conditions. In the stylolitic case, i.e., when the main principal stress is normal to the interface, two different stabilizing terms dominate at small and large scales which are linked respectively to the surface energy and to the elastic interactions. Integrating the presence of small‐scale heterogeneities related to the rock properties of the grains in the model leads to the formulation of a Langevin equation predicting the dynamic evolution of the surface. This equation leads to saturated surfaces obeying the two observed scaling laws. Analytical and numerical analysis of this surface evolution model shows that the crossover length separating both scaling regimes depends directly on the applied far‐field stress magnitude. This method gives the basis for the development of a paleostress magnitude marker. We apply the computation of this marker, i.e., the morphological analysis, on a stylolite found in the Dogger limestone layer located in the neighborhood of the ANDRA Underground Research Laboratory at Bure (eastern France). The results are consistent with the two scaling regimes expected, and the practical determination of the major principal paleostress, from the estimation of a crossover length, is illustrated on this example.
Contribution of atmospheric nitrogen deposition to new production in the nitrogen limited photic zone of the northern Indian Ocean
Authors: Singh Arvind , Gandhi Naveen , Ramesh R.
Published: May 2012

Primary productivity in the sunlit surface layers of tropical oceans is mostly limited by the supply of reactive nitrogen (Nr) through upwelling, N2 fixation by diazotrophs, riverine flux and atmospheric deposition. The relative importance of these processes varies from region to region. Using recent data on the nitrogen content of aerosols over the ocean and marine new production in parts of the northern Indian Ocean for the period 1994–2006 CE, a quantitative assessment of the contribution of atmospheric deposition to new production in the two biogeochemically different basins of the northern Indian Ocean, viz., the Arabian Sea and the Bay of Bengal, is presented. By suitably converting the measured concentrations of aerosol nitrogen into fluxes and comparing them with 15N tracer‐based direct new and primary production measurements, it is inferred that the contribution of atmospheric deposition to new production in the northern Indian Ocean could at best be ∼3%. Our estimate of ∼1.39 Tg N year−1 of Nr flux into the northern Indian Ocean through aerosols is a step toward significantly reducing the uncertainty in the global nitrogen budget.
Contributions to sea level variability along the Norwegian coast for 1960–2010
Authors: Richter K. , Nilsen J. E. Ø. , Drange H.
Published: May 2012

Global sea level has been rising by about 20 cm during the last century and is expected to continue to rise in the 21st century. The rise and variability is not spatially uniform. To be able to project local changes in relative sea level (RSL), it is important to identify the processes that govern regional RSL variability. In this study, we assess the importance of different contributions to RSL variability along the coast of Norway in the period 1960–2010. By using hydrographic station data at the coast, sea level pressure, and observed vertical land uplift, we compute RSL changes due to thermal expansion, haline contraction, the inverted barometer effect, and land uplift caused by glacial isostatic adjustment. The combination of these contributions is compared to RSL variability observed with tide gauges. For all but the two southernmost stations, the reconstructed RSL explains 70–85% of the observed variability of the monthly sampled time series. The inverted barometer effect is responsible for more than half of the explained variability, while thermosteric height represents the largest contribution to the linear trend. Due to land uplift, the local RSL rise is weaker and partly negative along the Norwegian coast. The residual (observed minus reconstructed) shows a positive trend ranging from 1.3 mm yr−1 to 2.3 mm yr−1. It is speculated that the reason for this is an increase of mass in the ocean due to melting of land‐based ice and, to a lesser degree, the combined thermohaline expansion in the deep Nordic seas.
Changes of the prevailing trade winds over the islands of Hawaii and the North Pacific
Authors: Garza Jessica A. , Chu Pao‐Shin , Norton Chase W. , Schroeder Thomas A.
Published: May 2012

Changes in the frequency and intensity of the prevailing northeast and east trade winds from 1973‐2009 are analyzed from four land stations in the Hawaiian Islands. A nonparametric robust trend analysis indicates a downward trend in northeast trade wind frequency since 1973. At the Honolulu International Airport, northeast trade wind days usually occurred 291 days per year 37 years ago are observed to occur only 210 days per year in 2009. In contrast, the frequency of the east trade winds has increased over the past 37 years. Comparison of observations from four ocean buoys with land stations for the last 26 years (1984–2009) is presented. The northeast trade frequency is found to decrease for all eight stations while the east trade winds are found to increase in frequency. These results are similar to the longer (1973–2009) data set. Most buoys revealed an increase in trade wind speeds since 1984. The NCEP/NCAR reanalysis II data are used to analyze surface winds and sea level pressure (SLP) over the north Pacific. A northeast to east shifting of winds and an increase in SLP is found to occur from the 1980s to the 2000s epoch. Linear trends in reanalysis II from 1980 to 2009 indicated a strengthening of northeast trade winds over the Hawaiian Islands and in the subtropical eastern North Pacific with an extension of increased northerlies off the California coast. Meanwhile, southeast trades in the eastern North Pacific reduced their strength. Changes in trades in the western Pacific are relatively small.
Impact of assimilation of Atmospheric InfraRed Sounder (AIRS) radiances and retrievals in the WRF 3D‐Var assimilation system
Authors: Singh Randhir , Kishtawal C. M. , Ojha Satya P. , Pal P. K.
Published: May 2012

This study compares the performance of the advanced research version of the Weather Research and Forecasting (WRF) model in response to the assimilation of AIRS radiances and retrievals. The WRF model and its three‐dimensional variational (3D‐Var) data assimilation system is used to assimilate AIRS measurements (radiances and retrievals) and the impacts of these measurements are evaluated on the analysis and 24‐h forecasts over the Indian region for the entire month of July 2010. A rigorous validation is produced against HIRS and Kalpana VHRR radiances, NCEP analysis, and TRMM observed precipitation. Results show that the assimilation of AIRS measurements has a significant impact on WRF analysis and short range forecasts. The radiances simulated using WRF analyzed and forecast fields, assimilated with AIRS measurements, match significantly closer to HIRS and Kalpana VHRR radiances, relative to simulations without AIRS measurements (the control run). Assimilation of AIRS measurements leads to improvement of moisture, temperature, winds and rainfall forecast with respect to control run. This study indicates that assimilation of radiances and bias‐adjusted retrievals perform equally well when NCEP analysis is used for the verification, and it is found that analysis and forecasts resulting from assimilated AIRS radiances and bias‐adjusted retrievals are of better quality compared to those obtained by assimilating retrievals without bias‐adjustment.
Using environmental variables and soil processes to forecast denitrification potential and nitrous oxide fluxes in coastal plain wetlands across different land uses
Authors: Morse Jennifer L. , Ardón Marcelo , Bernhardt Emily S.
Published: May 2012

We examined relationships between denitrification (DNF) and nitrous oxide (N2O) fluxes and potentially important chemical and physical predictors to build a predictive understanding of gaseous N losses from coastal plain wetlands. We collected soil, gas, and pore water samples from 48 sampling locations across a large (440 ha) restored wetland, an adjacent drained agricultural field, and nearby forested wetlands every two months over two years. In summer and fall 2007, we measured soil DNF potential (21.6–3560 mg N m−3d−1) and N2O efflux (−4.36–8.81 mg N m−2d−1), along with 17 predictor variables. We developed statistical models for the most comprehensive subset of the data set (fall 2007) and used another subset (summer 2007) for cross‐validation. Soil pH and total soil nitrogen were the best predictors of DNF potential (Radj2= 0.68). A regression using carbon dioxide flux and soil temperature together with soil extractable NH4+and DNF potential explained 85% of the variation in fall N2O fluxes. The model for DNF performed reasonably well when cross‐validated with summer data (R2= 0.40), while the N2O model did not predict summer N2O fluxes (R2< 0.1). Poor model performance was likely due to nonlinear responses to high temperatures and/or higher and more variable root respiration by plants during the growing season, leading to overprediction of N2O flux. Our results suggest that soil DNF potential may be modeled fairly effectively from a small number of soil parameters, that DNF potential is uncorrelated with N2O effluxes, and that successful estimation of wetland N2O effluxes will require finer‐scale models that incorporate seasonal dynamics.
Temperature dynamics of a proglacial stream: Identifying dominant energy balance components and inferring spatially integrated hydraulic geometry
Authors: Magnusson Jan , Jonas Tobias , Kirchner James W.
Published: May 2012

Proglacial fields typically have complex topography and heterogeneous sediments, resulting in highly variable flow and temperature regimes in surface runoff and groundwater. Using data from the Damma glacier forefield (Switzerland), we examined how longitudinal stream temperature changes can be used to infer reach‐averaged hydrological and thermal processes in proglacial riparian zones. A simple energy balance showed that (1) radiative forcing and frictional warming largely explained the observed temperature patterns in three stream reaches, and that (2) groundwater inflow and/or hyporheic exchange appear to influence stream warming along a fourth reach. Daytime stream warming depends on channel width, and here we show that stream temperature measurements can be used to infer reach‐averaged hydraulic geometry relationships between stream width and discharge, which are normally difficult to obtain by other methods in braided gravel bed streams. Our results illustrate how proglacial stream temperatures can yield spatially integrated information about hydrological and thermal processes in glacial forefields, where extreme spatial heterogeneity makes conventional methods difficult to apply.
Groundwater pressure changes in Central Japan induced by the 2011 off the Pacific coast of Tohoku Earthquake
Authors: Niwa Masakazu , Takeuchi Ryuji , Onoe Hironori , Tsuyuguchi Koji , Asamori Koichi , Umeda Koji , Sugihara Kozo
Published: May 2012

In the 2011 off the Pacific coast of Tohoku Earthquake, groundwater pressure changes were observed in and around the Mizunami Underground Research Laboratory (MIU) in Central Japan, where two vertical shafts and horizontal research galleries are excavated in the granitic rock mass. Coseismic changes of groundwater pressure are believed to correspond to crustal dilation/contraction induced by earthquakes. In this study we calculated volumetric strain changes due to the Tohoku Earthquake based on previously reported fault slip models. The calculation indicates approximately 2 × 10−7 of dilational strain around the MIU. Based on the strain sensitivities calculated from tidal responses at the monitoring boreholes, the dilation corresponds to drawdowns of several tens of centimeters, and is almost the same as the drawdown observed in the boreholes at distances greater than 1 km from the MIU. In contrast, rapid elevation of groundwater pressures associated with the earthquake was observed in the boreholes within the 500 m vicinity of the MIU. The anomalous elevation is explained by a temporary recovery of the drawdown due to excavation of the shafts and a unique permeability increase induced by the coseismic dilation of heterogeneous local geological structures such as impervious faults controlling the hydrogeological environment.