bluuebunny/crossref_metadata_2025 huggingface dataset:
The Shenandoah University Midwifery Initiative: A Model for Midwifery Education
Authors: Fehr Juliana van Olphen
Published: March 2008

There has been a significant decline in the number of nurse‐midwifery education programs in the United States in the past decade. This decline presents a challenge as the profession seeks to respond to the Pew Foundation's call to increase access to midwifery care in the United States. Collaborative arrangements between universities that house nurse‐midwifery programs and other universities in the region could be an effective strategy to increase access to nurse‐midwifery education, thereby increasing access to nurse‐midwifery care.
The Effect of Vigorous Exercise During Pregnancy
Authors: Penney Debra S.
Published: March 2008

Pregnant women without medical or obstetric problems should be encouraged to exercise. The paucity of experimental data on exercise in pregnancy forces recommendations to be drawn from a synthesis of available information. Vigorous exercise during pregnancy seems to pose no adverse maternal or neonatal outcomes. Nonetheless, the safety of vigorous exercise necessitates surveillance of fetal growth, the woman's weight, nutritional intake, and exercise duration and intensity.
The Stakes of Inclusion: Chinese Canadian Head Tax Redress
Authors: Winter Stephen
Published: March 2008

Abstract.Between 1885 and 1923 Canada imposed a discriminatory head-tax on Chinese immigrants. In 2006 Canada implemented a material redress program intended to resolve this historical injustice, but aspects of this program have been subjected to vigorous criticism by those seeking greater inclusivity. Paying particular attention to the program's intergenerational aspects, this study explores how the current program's conceptualization of a valid redress claim is situated with respect to both its critics and to domestic and international precedents. Recognizing the dynamic potentiality of redress, the study explores aspects of why and how Canada's understandings of historical redress are politically implicated.

Résumé.Entre 1885 et 1923 le Canada a imposé un impôt discriminatoire aux immigrés chinois. En 2006, le Canada a mis en oeuvre un programme de réparation afin de redresser cette injustice historique, mais certains aspects de ce programme sont vivement critiqués par les partisans d'une plus grande inclusivité. Se concentrant en particulier sur les aspects intergénérationnels du programme, cette étude analyse la manière dont le programme actuel situe la conceptualisation d'une demande légitime de réparation en fonction à la fois de ses détracteurs et de précédents nationaux et internationaux. Prenant en compte le potentiel dynamique de la réparation, cette étude analyse les implications politiques de la démarche canadienne de redressement historique.
Les styles discursifs des premiers ministres québécois de Jean Lesage à Jean Charest
Authors: Monière Denis , Labbé Cyril , Labbé Dominique
Published: March 2008

Résumé. La forme, le style du discours des hommes politiques sont révélateurs de leurs personnalités et de leurs stratégies de communication. Pour analyser les styles des premiers ministres québécois, un corpus comprenant 789 discours officiels prononcés de 1960 à 2005 a été soumis à une analyse de stylistique quantitative. Nous avons analysé les catégories grammaticales, le maniement des verbes et des noms, la longueur et la structure des phrases. Cette comparaison statistique montre des différences significatives entre les premiers ministres et révèle également la stratégie de communication privilégiée par chacun d'eux.

Abstract. The style of politician speeches reveals their personalities and their communication strategies. In order to analyse the style of Quebec prime ministers, from 1960 to 2005, a corpus of 789 speeches have been built up and a quantitative stylistic analysis has been applied to it. The main indicators used are the grammatical categories, especially the verbs and pronouns, the length and the structure of the sentences. This statistical comparison shows some important differences between the styles of the prime ministers and between the communication strategies they have followed.
Freedom of Speech in Early Stuart England
Authors: King Ed
Published: March 2008

Freedom of Speech in Early Stuart England, David Colclough, Cambridge: Cambridge University Press, 2005, pp. 314.

The rhetorical lynchpin of this fascinating book's central argument is the concept of parrhesia, which is a Greek term that began life as a catch-all expression for the quality of speech belonging to citizens of the polis (6). Colclough implies that the tradition of parrhesia took a circular route via the freedom of expression inherent in the group rights of Greek citizens to the need for frank expression of unpleasant truths by courtiers to their rulers. This transition required that “frankness” be elevated to the status of a virtue once it became apparent that rulers did not always make decisions in the best interest of the state. After the Reformation in northern Europe this virtue evolved into a religious imperative in the face of sectarian persecution and in England, especially, this imperative naturally extended itself to the admonition of monarchs who encroached on their citizens' religious freedoms. Religious conflict led to war, war required economic investment and soon the religious imperative to oppose the wrong-headed heretic blended with a protestant parliament's right to admonish the monarch on purely secular matters. Thus, under the Stuarts, parrhesia eventually came to resume its original sense as the right and duty of a free subject to speak out in public without fear that his desire to preserve the common good would be prosecuted under laws aimed at the seditious and libelous. It is but a rising sense of the secular that enables us to recognize the change in values that led an onerous religious duty to become the unimpeachable liberal right we so casually assert today.
Russia Transformed: Developing Popular Support for a New Regime
Authors: Chandler Andrea
Published: March 2008

Russia Transformed: Developing Popular Support for a New Regime, Richard Rose, William Mishler and Neil Munro, Cambridge and New York: Cambridge University Press, 2006, pp. xii, 226.

This monograph analyzes major findings of fourteen years of public opinion research in Russia carried out under the New Russia Barometer survey research project, which Rose and colleagues conducted in conjunction with the Levada Centre in Russia. Rose, Mishler and Munro offer a clearly written, focused discussion that puts complex data into perspective. The work's major contribution is its systematic evaluation of the evolution of Russian citizens' political attitudes from 1992 to 2005. As the authors note in their dedication to the volume, their surveys included over 28,000 people across Russia (the methodology is outlined on pp. 70–75). As such, the book's authority in providing an accurate reflection of citizens' views is indisputable. Much to their credit, the authors render their findings readily understandable to readers who are not expert in survey research design or quantitative methods.
Escaping the Resource Curse
Authors: Carter Angela V.
Published: March 2008

Escaping the Resource Curse, Macartan Humphreys, Jeffrey D. Sachs and Joseph E. Stiglitz, eds., Foreword by George Soros; New York: Columbia University Press, 2007, pp. xviii, 408.

Escaping the Resource Curse provides economic and political analysis of resource curse theories as well as practical policy advice to governments on managing oil and gas developments. Twelve chapters by natural resource specialists from multiple disciplines discuss a broad range of oil and gas development issues in three sections, “Dealing with Oil Corporations,” “Managing the Macroeconomy,” and “Handling the Politics.” Beyond the specific policy advice elaborated in detail throughout (relating primarily to transparency), the book succeeds in its accessible analysis of resource curse theories and state-industry tensions as well as its reinterpretation of oil wealth.
Parole d'historiens. Anthologie des réflexions sur l'histoire au Québec
Authors: Perreault Isabelle
Published: March 2008

Parole d'historiens. Anthologie des réflexions sur l'histoire au Québec, Éric Bédard et Julien Goyette (dirs), Les Presses de l'Université de Montréal, 2006, 492 pages.

Cette anthologie de réflexions sur la pratique historienne au Québec est issue du désir de faire connaître les essais, les bilans et les réflexions théoriques sur l'historiographie au Québec depuis le dix-huitième siècle. Deux historiens québécois, Éric Bédard et Julien Goyette, en sont les tributaires. Par ce projet de publication de textes d'historiens de chez nous s'échelonnant sur près de trois siècles, les présentateurs de l'ouvrage voulaient aussi faire réfléchir sur la théorie et la pratique historique actuelle. Comme le souligne Bédard dans l'introduction de l'ouvrage, il s'agit de “nourrir [les] réflexions sur l'écriture de l'histoire au Québec et les finalités de la recherche” (11). En outre, bien que la discipline historique soit traditionnellement rattachée au domaine des Arts et Lettres, les historiens se sont toujours interrogés sur l'histoire en tant que discipline des sciences humaines et ils ont tenté de répondre aux grandes questions sur le sens et le rôle de l'histoire. L'histoire est-elle une science ou un grand récit ? L'historien doit-il être attentif aux enjeux présents ou tenter d'en faire abstraction ? L'historien est-il un chercheur en quête de vérité ou un critique des grands mythes de la nation ? Ces questions, et bien d'autres, se retrouvent dans les textes des historiens réunis dans cette anthologie.
Dancing Around the Elephant: Creating a Prosperous Canada in an Era of American Dominance, 1957–1973
Authors: Miljan Lydia
Published: March 2008

Dancing Around the Elephant: Creating a Prosperous Canada in an Era of American Dominance, 1957–1973, Bruce Muirhead, Toronto: University of Toronto Press, pp. 323.

Canadian feelings of anti-Americanism have a long history. Some have suggested that Canada was born more out of a sense of wanting to protect itself from American invaders than with a sense of what it was. The view that Canada is the lesser state is seen in Pierre Trudeau's comment to the Washington Press Gallery in 1969: “Living next to you, is like sleeping with an elephant; no matter how friendly and even-tempered is the beast, one is affected by every twitch and grunt.” The elephant-mouse metaphor has been one of the best ones to describe the relationship between the two nations and is often used by left-leaning Canadian nationalists to illustrate how much weaker Canada is in the partnership.
Agir maintenant pour le Québec de demain, sous la direction de Luc Godbout.
Authors: Bourque Mélanie
Published: March 2008

Agir maintenant pour le Québec de demain, sous la direction de Luc Godbout., Luc Godbout, Les Presses de l'Université Laval, 2006, 264 pages.

L'ouvrage Agir maintenant pour le Québec de demain s'est fixé trois objectifs. Le premier est de mettre en lumière les positions divergentes des Lucides et des Solidaires; le second est d'ouvrir le dialogue entre les tenants de l'une et l'autre tendance; le troisième est de trouver des pistes de solutions qui pourront assurer le maintien des programmes sociaux tels qu'ils existent aujourd'hui pour les générations futures. On peut affirmer que l'ouvrage atteint le premier et le troisième objectifs, mais on ne peut en dire autant du second objectif, puisque le dialogue semble pour le moins difficile.
Building States without Society: European Union Enlargement and the Transfer of EU Social Policy to Poland and Hungary
Authors: Boardman Robert
Published: March 2008

Building States without Society: European Union Enlargement and the Transfer of EU Social Policy to Poland and Hungary, Beate Sissenich, Lanham, MD: Lexington Books, 2007, pp. xiv, 237.

Social policy has been a crucial and at times controversial area for the European Union, yet it remains limited in scope and clout. EU social policy is not a major annoyance of a kind to alarm employers nor does it present labour unions with tantalizing opportunities for social change. It does not deal with redistribution politics and does not establish an EU-level welfare state. Important topics are left out. In the negotiations before the 2004 enlargement, the issues of mobility and the freedom of movement of persons—politically charged issues in view of the fears on the part of some older members of a significant influx of workers from new lower-wage EU states—were handled in a separate negotiating chapter.
Order and Anarchy: Civil Society, Social Disorder and War
Authors: Noel Sid
Published: March 2008

Order and Anarchy: Civil Society, Social Disorder and War, Robert Layton, Cambridge: Cambridge University Press, 2006, pp. vi, 197.

All societies undergo periods of stress from time to time, whether caused by internal factors or by radical changes in their economic, political or other environments. Why do some make the necessary adjustments by peaceful political means with relatively little disruption of their underlying social order while others spiral into violence, social disorder and (not infrequently) inter-communal warfare? This is a question that has long engaged political theorists and in this short book Robert Layton reflects upon it from the perspective of an anthropologist. His subject is nothing less than the role of violence in human evolution.
L'égalité introuvable. La parité, les féministes et la République
Authors: Tremblay Manon
Published: March 2008

L'égalité introuvable. La parité, les féministes et la République, Éléonore Lépinard, Les Presses de sciences po (Collection Fait politique), 2007, 293 pages.

La parité, ou l'idée que les sièges dans les assemblées élues devraient être partagés également entre les femmes et les hommes, a fait couler beaucoup d'encre, surtout depuis la première moitié des années 1990. Dans ce contexte d'abondance, l'apport original de L'égalité introuvable est d'étudier cette problématique sous l'angle du processus de légitimation discursive, c'est-à-dire en s'interrogeant sur les normes juridiques et politiques qui ont rendu possible la parité. En d'autres mots, Lépinard cherche à mettre au jour les mécanismes discursifs qui ont permis que la revendication de la parité soit mise en conformité avec les valeurs de la République française, notamment celles de l'égalité formelle de tous les citoyens et de l'universalisme abstrait.
Perioperative placement of stents for relief of proximal pulmonary arterial stenoses in infants
Authors: Sreeram Narayanswami , Emmel Mathias , Ben Mime Lotfi , Brockmeier Konrad , Bennink Gerardus
Published: March 2008

Introduction

Stenoses in the pulmonary arterial system can have a significant negative impact on the early postoperative course in infants. Early recognition and aggressive management are mandatory.

Patients and methods

We describe our experience with 8 infants, with ages ranging from 3 to 9 months, weighing from 4.5 to 7.7 kilograms, who presented in the up to 18 days following construction of a shunt from the superior caval vein to the pulmonary arteries with clinical symptoms of obstructed pulmonary flow. We include also 2 infants in whom pulmonary arterial stents were implanted in the operating room. Cardiac catheterization showed significant stenoses or occlusion of the left pulmonary arteries in 9 infants, the right pulmonary arteries in 2, or the superior caval vein in 1, the investigation being prompted by the findings of supraphysiological superior caval venous pressures and systemic hypoxaemia. We implanted a variety of stents mounted on balloons ranging in diameter from 6 to 13 millimetres, with 7 placed across a newly created surgical anastomotic site.

Results

All stenoses were crossed successfully, and stents implanted satisfactorily in all patients, albeit that 1 infant suffered an acute tear of the left pulmonary artery, requiring immediate reoperation. This patient died 72 hours later due to a diffuse coagulopathy. All other patients demonstrated sustained clinical improvement following the procedure. At follow-up, 7 of the 9 survivors have progressed to completion of the Fontan circulation. Redilation of the stents was required in the interim, prior to completion of the Fontan circulation, in 4 of them. In 2 patients, the previously implanted stents were incised during the Fontan completion, permitting placement of the extracardiac Goretex conduit from the inferior caval vein to the pulmonary arteries.

Conclusions

Stents can successfully be implanted perioperatively in the pulmonary arterial system during infancy, and redilated, with improvement in clinical outcome in the majority of those with clinically relevant obstruction.
Role of caval venous manipulation in treatment of protein-losing enteropathy
Authors: Menon Shaji , Hagler Donald , Cetta Frank , Gloviczki Peter , Driscoll David
Published: March 2008

Protein-losing enteropathy has been associated with the Fontan operation, restrictive cardiomyopathy, constrictive pericarditis, tricuspid valvar stenosis and insufficiency, and superior caval venous obstruction. The mechanism of development of this complication of cardiac disease likely is multifactorial. We report here our experience with 3 patients with protein-losing enteropathy. Two had superior caval venous occlusion. The third patient had undergone an extracardiac Fontan operation, with stenosis of the extracardiac conduit placed to the right pulmonary artery. In all three cases, the complication was resolved by restoring unobstructed flow of blood in the superior or inferior caval vein. Since the aetiology of protein-losing enteropathy associated with cardiac disease is multifactorial, reduction of pressure in the tributaries of the superior caval vein may, in some cases, be curative. It is more difficult to cure the problem when it is associated with the Fontan operation.
Patterns of use of educational and rehabilitation services at school age for children with congenitally malformed hearts
Authors: Majnemer Annette , Mazer Barbara , Lecker Emily , Leduc Carter Alison , Limperopoulos Catherine , Shevell Michael , Rohlicek Charles , Rosenblatt Bernard , Tchervenkov Christo
Published: March 2008

Background

Infants with congenitally malformed hearts who require early open-heart surgery are at high risk for developmental, psychosocial, and academic difficulties. Our objective was to describe the pattern of use of educational supports and rehabilitation services in these children at early school age.

Methods

Parents of children who participated in a prospective study of developmental progress following open-surgery were contacted to participate in a telephone survey. The questionnaire included questions regarding current educational and rehabilitation resources their child was receiving, as well as the needs perceived by the parents for services, and obstacles to accessing services.

Results

The survey was completed by 60 families, the mean age of the children being 8.1 years, with standard deviation of 1.1 years. Of the children, 22% received educational supports, which primarily included supplemental tutoring. Rehabilitation services were received by 23%, speech therapy for 9 children, psychologic support for 6, occupational therapy for 3, and physical therapy for 1. Children receiving these services were significantly more likely to have had low developmental scores in the expected domains, when compared to those not receiving services. The majority of developmentally delayed children were not receiving adequate, if any, resource support. Medical and surgical history was not associated with greater likelihood of receipt of services.

Conclusions

Children with congenitally malformed hearts who are now of school age are at risk for developmental challenges and academic difficulties, yet many do not receive services to optimize performance. Modification of current practice to include systematic, periodic screening, as well as the availability of a resource person for information and referral, may be warranted to meet the ongoing needs of these children and their families, and to optimize their health and well-being.
Five-year incidence of obesity and its determinants: the ATTICA Study
Authors: Yannakoulia Mary , Panagiotakos Demosthenes , Pitsavos Christos , Lentzas Yannis , Chrysohoou Christina , Skoumas Ioannis , Stefanadis Christodoulos
Published: March 2008

Objectives

To evaluate the 5-year incidence of obesity in a sample of CVD-free adults and investigate the potential effect of several sociodemographic and lifestyle habits on weight change and obesity incidence in these individuals.

Methods

Men (n 1514) and women (n 1528) (>18 years) without any clinical evidence of CVD, living in the Attica area of Greece, were enrolled in the ATTICA study from May 2001 to December 2002. The sampling was random, multistage and included information about various sociodemographic, lifestyle (diet, exercise and smoking), biochemical and clinical characteristics. In 2006, the 5-year follow-up was performed through telephone calls or personal visits. Data from the 1364 participants are analysed in the present work.

Results

The 5-year incidence of obesity was 21·8 % in men and 11·9 % in women. The ratio of men to women revealed that more men than women developed obesity, while more women than men became overweight during the follow-up period. It was found that men were 1·6 times more likely to develop obesity compared with women; abnormal waist circumference, smoking habits and the presence of hypercholesterolaemia increased the risk for developing obesity, irrespective of age and baseline lifestyle characteristics of the participants. In the multivariate analysis, no association was detected between adherence to a Mediterranean diet and incidence of obesity in initially normal-weight individuals.

Conclusions

Obesity remains a serious health problem for the Greek population; the alarming rates of excess body weight continue to increase. Preventive measures should be urgently addressed, targeting particularly those with metabolic risk factors.
Changes in the sensation of hunger and well-being before and after meals in overweight/obese women following two types of hypoenergetic diet
Authors: Rodríguez-Rodríguez Elena , Aparicio Aránzazu , Bermejo Laura M , López-Sobaler Ana M , Ortega Rosa M
Published: March 2008

Objective

To analyse changes in the sensation of hunger and the sensation of well-being of young overweight/obese women following two hypoenergetic diets.

Design, setting and subjects

Fifty-seven women (BMI = 24–35 kg/m2) were randomly assigned to one of two hypoenergetic diets: diet V, in which the consumption of vegetables was increased; or diet C, in which the consumption of cereals (especially breakfast cereals) was increased. Dietetic and anthropometric data and an evaluation of the sensation of hunger and well-being were collected at the start and end of the study, 6 weeks later.

Results

The diets led to a reduction in weight and BMI in both groups. The sensation of hunger at the end of meals was higher at the end of the study than at the start in both groups. At 6 weeks, the sensation of well-being after breakfast, morning snack and lunch, as well as the mean sensation of well-being after all meals, was greater in diet C. Compared with that recorded at the beginning of the study, the capacity to experience satiety at the end of meals also increased with diet C, as did the capacity to experience well-being at 6 weeks (for breakfast, lunch, dinner and for the mean for all meals). This capacity to experience well-being was also greater in diet C than in diet V with respect to the mid-morning snack and lunch.

Conclusion

The more positive results obtained with diet C may contribute to the increased weight loss seen in that group and their lower withdrawal rate.
Characterization of Protein Capacity of Nanocation Exchanger Particles as Filling Material for Functional Magnetic Beads for Bioseparation Purposes
Authors: Hickstein Birgit , Peuker Urs A.
Published: March 2008

In this study we describe the synthesis and characterization of nanocation exchanger particles (NCEX) as the functional filling material for magnetic beads. Polystyrene NCEX particles were synthesized from styrene via a miniemulsion polymerization. The coupling of cation exchanger groups was done with chlorosulfuric acid after the polymerization reaction. The NCEX particles have an average diameter of 160–260 nm. Their ion exchange capacity amounts up to 4.58 mval/g. In an adsorption experiment it was possible to adsorb 192 mg lysozyme/g NCEX. Depending on the equilibrium concentration of lysozyme in the bulk solution 70–85% of the attached protein was desorbed. NCEX particles were used to produce magnetic beads with cation exchanger properties. Therefore an innovative production process for the synthesis of magnetic beads from different single components was used. The produced magnetic beads contained 40 wt % NCEX material and showed an ion exchanger capacity of 2 mequiv/g. It was possible to adsorb 75 mg lysozyme/g magnetic beads with a maximum recovery rate of 95%.
Ultra Scale‐Down To Define and Improve the Relationship between Flocculation and Disc‐Stack Centrifugation
Authors: Berrill Alex , Ho Sa V. , Bracewell Daniel G.
Published: March 2008

The recovery of intracellular recombinant proteins produced in microbial systems typically requires physical, chemical or thermal treatment of the cells post‐harvest to release the product into the broth, followed by removal of the cell debris using centrifugation or tangential flow filtration. Often a precipitation or flocculation step is introduced to facilitate the liquid‐solid separation. Due to the complex nature of the cell materials and the unit operations, it is difficult to obtain data at laboratory scale that closely reflect the performance of these operations on larger scales (pilot or manufacturing). This study uses a predictive scale‐down model that enables rapid optimization of the operating conditions for a flocculation followed with a centrifugation step using only small volumes (20 mL) of a high solids (∼20% w/w) E. coli heat extract. Results obtained show that, with proper theoretical and experimental consideration to account for high cell density, conditions could be found that improve the beneficial interaction between flocculation and centrifugation. These experiments suggested that adding a higher level of a cationic polymer could substantially increase the strength of the flocculated particles produced, thereby enhancing overall clarification performance in a large scale centrifuge. This was subsequently validated at pilot scale.
Applying Near‐Infrared Spectroscopy in Downstream Processing: One Calibration for Multiple Clarification Processes of Fermentation Media
Authors: Rodrigues Licínia O. , Cardoso Joaquim P. , Menezes José C.
Published: March 2008

The use of near‐infrared spectroscopy (NIRS) is demonstrated in the first downstream processing (DSP) steps of an active pharmaceutical ingredient (API) manufacturing process. The first method developed was designed to assess the API content in the filtrate stream (aqueous) of a rotary drum vacuum filter. The PLS method, built after spectral preprocessing and variable selection, had an accuracy of 0.01% (w/w) for an API operational range between 0.20 and 0.45% (w/w). The robustness and extrapolation ability of the calibration was proved when samples from ultrafiltration and nanofiltration processes, ranging from 0 to 2% (w/w), were linearly predicted ( R2=0.99). The development of a robust calibration model is generally a very time‐consuming task, and once established it is imperative that it can be useful for a long period of time. This work demonstrates that NIR procedures, when carefully developed, can be used in different process conditions and even in different process steps of similar unit operations.
Design of Protein‐Releasing Chitosan Channels
Authors: Kim Howard , Tator Charles H. , Shoichet Molly S.
Published: March 2008

After traumatic injury to the spinal cord, the neural tissue degenerates, resulting in lost function below the site of injury. Promoting axonal regeneration after injury remains a challenge; however, guidance channels have demonstrated some success when combined with cellular and protein therapies. One of the limitations of current guidance channels is the inability to deliver therapeutically relevant molecules in situ, within the guidance channel, to enhance regeneration. In an effort to provide a system for local and sustained drug release, poly(lactide‐co‐glycolide) (PLGA) microspheres were embedded into chitosan guidance channels by a novel spin‐coating technique. The method was designed to create guidance channels with the appropriate dimensions for implantation into the spinal cord, with special attention paid to the wall thickness. The release and bioactivity of a model protein, alkaline phosphatase, was followed from the channels and compared to those from free‐floating microspheres over a 90‐day period. Since chitosan formulations often require the use of acidic solutions, careful attention was paid to redesign the process to minimize exposure of PLGA microspheres to acid. This was achieved as demonstrated by release and bioactivity data where alkaline phosphatase released from chitosan/microsphere channels followed a profile and bioactivity similar to those of free floating microspheres.
Magma‐driven multiple dike propagation and fracture toughness of crustal rocks
Authors: Jin Z.‐H. , Johnson S. E.
Published: March 2008

Dike swarms consisting of tens to thousands of subparallel dikes are commonly observed at Earth's surface, raising the possibility of simultaneous propagation of two or more dikes at various stages of a swarm's development. The behavior of multiple propagating dikes differs from that of a single dike owing to the interacting stress fields associated with each dike. We analyze an array of parallel, periodically spaced dikes that grow simultaneously from an overpressured source into a semi‐infinite, linear elastic host rock. To simplify the analysis, we assume steady state (constant velocity) magma flow and dike propagation. We use a perturbation method to analyze the coupled, nonlinear problem of multiple dike propagation and magma transport. The stress intensity factor at the dike tips and the opening displacements of the dike surfaces are calculated. The numerical results show that dike spacing has a profound effect on the behavior of dike propagation. The stress intensity factors at the tips of parallel dikes decrease with a decrease in dike spacing and are significantly smaller than that for a single dike with the same length. The reduced stress intensity factor indicates that, compared to a single dike, propagation of parallel dikes is more likely to be arrested under otherwise the same conditions. It also implies that fracture toughness of the host rock in a high confining pressure environment may not be as high as inferred from the propagation of a single dike. Our numerical results suggest fracture toughness values on the order of 100 MPa . The opening displacements for parallel dikes are smaller than that for a single dike, which results in higher magma pressure gradients in parallel dikes and lower flux of magma transport.
Tropospheric circulation sensitivity to an interactive stratospheric ozone
Authors: Brand S. , Dethloff K. , Handorf D.
Published: March 2008

For this conceptual study we focus on the impact of interactive stratospheric ozone chemistry on the tropospheric circulation, using the atmosphere‐ocean‐sea ice general circulation model (AOGCM) ECHO‐GiSP with simplified stratospheric chemistry. The model covers the troposphere and middle atmosphere up to 80 km height. Our results show a clear sensitivity of the tropospheric circulation dynamics to the stratospheric chemistry. With enabled interactive stratospheric chemistry the model tends to the negative phase of the Arctic Oscillation (AO) mode. This also includes an enhanced midlatitudinal planetary and synoptic scale wave activity. The strengthening of the synoptic scale waves leads to stronger stormtracks, while the planetary scale waves show larger changes outside this particular latitudes. Another tropospheric region, which is influenced by interactive stratospheric chemistry effects, is the tropical troposphere. Due to changes in lower stratospheric ozone concentrations a significant cooling appears in the positive AO‐phase compared to the negative phase.
Solar‐terrestrial coupling evidenced by periodic behavior in geomagnetic indexes and the infrared energy budget of the thermosphere
Authors: Mlynczak Martin G. , Martin‐Torres F. Javier , Mertens Christopher J. , Marshall B. Thomas , Thompson R. Earl , Kozyra Janet U. , Remsberg Ellis E. , Gordley Larry L. , Russell James M. , Woods Thomas
Published: March 2008

We examine time series of the daily global power (W) radiated by carbon dioxide (at 15 μm) and by nitric oxide (at 5.3 μm) from the Earth's thermosphere between 100 km and 200 km altitude. Also examined is a time series of the daily absorbed solar ultraviolet power in the same altitude region in the wavelength span 0 to 175 nm. The infrared data are derived from the SABER instrument and the solar data are derived from the SEE instrument, both on the NASA TIMED satellite. The time series cover nearly 5 years from 2002 through 2006. The infrared and solar time series exhibit a decrease in radiated and absorbed power consistent with the declining phase of the current 11‐year solar cycle. The infrared time series also exhibits high frequency variations that are not evident in the solar power time series. Spectral analysis shows a statistically significant 9‐day periodicity in the infrared data but not in the solar data. A very strong 9‐day periodicity is also found to exist in the time series of daily Ap and Kp geomagnetic indexes. These 9‐day periodicities are linked to the recurrence of coronal holes on the Sun. These results demonstrate a direct coupling between the upper atmosphere of the Sun and the infrared energy budget of the thermosphere.
Detecting seismogenic stress evolution and constraining fault zone rheology in the San Andreas Fault following the 2004 Parkfield earthquake
Authors: Taira Taka'aki , Silver Paul G. , Niu Fenglin , Nadeau Robert M.
Published: March 2008

We investigate temporal changes in seismic scatterer properties at seismogenic depth attributed to the 2004 M 6 Parkfield earthquake, making use of the San Andreas Fault Observatory at Depth repeating‐earthquake target sequences, as well as nearby similar‐earthquake aftershock clusters. We use a two‐step process: (1) observing temporal variations in the decorrelation index, D(t), reflecting changes in the scattered wavefield of repeating‐earthquake sequences and (2) estimating the spatial distribution of time‐dependent scatterers by using a larger‐aperture source array. We focus on three scatterers exhibiting clear time dependence, using pairs of earthquakes that span or follow the 2004 Parkfield earthquake. They are found to be located on the fault at the northernmost extent of coseismic rupture, beneath Middle Mountain, with a depth range of 11 to 17 km. The shallowest and most prominent scatterer is located near a region of increased Coulomb stress, as well as significant postseismic slip following the 2004 Parkfield earthquake, and a large M = 5 aftershock. The other two deeper ones are also in regions of increased Coulomb stress. We show that D(t)1/2 is expected to be proportional to the level of stress in the fault zone, and then we constrain the form of fault zone rheology by comparing the time dependence of D(t)1/2 with geodetic or seismic measures of strain rate, assuming a power law rheology between stress and strain rate characterized by exponent n. Such a comparison yields n ranging from 1.6 through 3.3, a value that is more consistent with ductile behavior, rather than frictional sliding, at the base of the seismogenic zone.
Lightning return stroke current radiation in presence of a conducting ground: 1. Theory and numerical evaluation of the electromagnetic fields
Authors: Delfino Federico , Procopio Renato , Rossi Mansueto
Published: March 2008

The general theory describing the electromagnetic field radiated by a lightning stroke over a conducting ground is presented in this paper. The derivation of the Green functions necessary to solve the problem is discussed in detail, and the determination of the expressions for the electromagnetic field components is carried out in a form that minimizes the final computational costs. A method for the numerical evaluation of the electromagnetic field is then proposed, and it is shown that it can be used starting from any “engineering model” representation for the lightning current distribution along the channel. Such method is based on a new efficient evaluation of the so‐called Sommerfeld's integrals appearing in the electromagnetic field expressions, without resorting to any kind of approximated formulas for them. The numerical treatment of the Sommerfeld's integrals is characterized by a proper subdivision of the integration domain, the use of the Romberg technique and the determination of a suitable upper bound for the error due to the integral truncation. In the second part of this work it will be shown how the results provided by the developed theory can be used in order to assess the validity of the most common simplified approach for the calculation of the lightning radiation over a lossy ground plane.
Barchan dune corridors: Field characterization and investigation of control parameters
Authors: Elbelrhiti H. , Andreotti B. , Claudin P.
Published: March 2008

The structure of the barchan field located between Tarfaya and Laayoune (Atlantic Sahara, Morocco) is quantitatively investigated and compared to that in La Pampa de la Joya (Arequipa, Peru). On the basis of field measurements, we show how the volume, the velocity, and the output sand flux of a dune can be computed from the value of its body and horn widths. The dune size distribution is obtained from the analysis of aerial photographs. It shows that these fields are in a statistically homogeneous state along the wind direction and present a “corridor” structure in the transverse direction, in which the dunes have a rather well selected size. Investigating the possible external parameters controlling these corridors, we demonstrate that none among topography, granulometry, wind, and sand flux is relevant. We finally discuss the dynamical processes at work in these fields (collisions and wind fluctuations) and investigate the way they could regulate the size of the dunes. Furthermore, we show that the overall sand flux transported by a dune field is smaller than the maximum transport that could be reached in the absence of dunes, i.e., in saltation over the solid ground.
Humidity control of particle emissions in aeolian systems
Authors: McKenna Neuman Cheryl , Sanderson Steven
Published: March 2008

Humidity is an important control of the wind speed required to entrain particles into an air flow and is well known to vary on a global scale, as do dust emissions. This paper reports on wind tunnel experiments which quantify this control through placing a polymer capacitance sensor immediately at the bed surface. The sensor measured changes in the humidity (RH) of the pore air in real time. RH was varied between 15% and 80% and the critical wind speed determined for the release of particles to the air stream. The results strongly support earlier suggestions that fine particles are most affected in relatively dry atmospheres, particularly those which are tightly packed. An analytical model is proposed to describe this relationship which depends on determination of the matric potential from the Kelvin equation. The total contact area between particle asperities adjoined by pendular rings is represented as a power function of the number of layers of adsorbed water. The value of the exponent appears to be governed by the surface roughness of the particles and their packing arrangement. Parallel developments in colloid interface science and atomic force microscopy, relevant to industrial and pharmaceutical applications, support these conclusions in principle and will likely have an important bearing on future progress in parameterization of the proposed model.
Coupled barrier island–resort model: 2. Tests and predictions along Ocean City and Assateague Island National Seashore, Maryland
Authors: McNamara D. E. , Werner B. T.
Published: March 2008

The fate of coastlines and their human settlements under the effects of global climate change will depend critically on the nonlinear dynamics of and feedbacks between shoreline processes and human agency. This hypothesis is explored on the barrier island coastline of Ocean City and Assateague Island National Seashore, Maryland, using a model‐coupling natural coastal processes, including erosion, accretion, island overwash, alongshore sediment transport, dune growth and migration, inlet migration and ebb tidal delta growth to economics of tourist resort development through storm damage and beach and dune replenishment. Initiating the model in 1845, the RMS difference between model and measurements of the shoreline position in 2001 is 84.97 m compared to a net onshore migration of 472.2 m and the RMS difference between modeled and measured hotel room density in 2001 is 2950 rooms km−1 compared to a net gain of 28,824 rooms km−1. Simulations to year 3400 for a rate of sea level rise of 3.5 mm a−1 show a steady state barrier island position 158 m further offshore and 0.54 m lower in elevation compared to its natural counterpart. Changing the rate of sea level rise to 10.5 mm a−1 increases these differences to 288 m and 0.76 m. Changing storminess by increasing the standard deviation of storm size 50% diminishes coupling between resorts and barriers, bringing the natural and coupled attractors into near coincidence. These results suggest that predicted increases in the rate of sea level rise will lead to enhanced vulnerability for Ocean City.
Late Albian paleoceanography of the western subtropical North Atlantic
Authors: Petrizzo Maria Rose , Huber Brian T. , Wilson Paul A. , MacLeod Kenneth G.
Published: March 2008

A late Albian–early Cenomanian record (∼103.3 to 99.0 Ma), including organic‐rich deposits and a δ13C increase associated with oceanic anoxic event 1d (OAE 1d), is described from Ocean Drilling Program sites 1050 and 1052 in the subtropical Atlantic. Foraminifera are well preserved at these sites. Paleotemperatures estimated from benthic δ18O values average ∼14°C for middle bathyal Site 1050 and ∼17°C for upper bathyal Site 1052, whereas surface temperatures are estimated to have ranged from 26°C to 31°C at both sites. Among planktonic foraminifera, there is a steady balance of speciation and extinction with no discrete time of major faunal turnover. OAE 1d is recognized on the basis of a 1.2‰ δ13C increase (∼100.0–99.6 Ma), which is similar in age and magnitude to δ13C excursions documented in the North Atlantic and western Tethys. Organic‐rich “black shales” are present throughout the studied interval at both sites. However, deposition of individual black shale beds was not synchronous between sites, and most of the black shale was deposited before the OAE 1d δ13C increase. A similar pattern is observed at the other sites where OAE 1d has been recognized indicating that the site(s) of excess organic carbon burial that could have caused the δ13C increase has (have) yet to be found. Our findings add weight to the view that OAEs should be chemostratigraphically (δ13C) rather than lithostratigraphically defined.
NEDD8 acts as a ‘molecular switch’ defining the functional selectivity of VHL
Authors: Russell Ryan C , Ohh Michael
Published: March 2008

The von Hippel–Lindau (VHL) tumour suppressor protein is important in the E3 ubiquitin ligase ECV (Elongin B/C–CUL2–VHL)‐mediated destruction of hypoxia‐inducible factor and the promotion of fibronectin (FN) extracellular matrix assembly. Although the precise molecular mechanism controlling the selectivity of VHL function remains unknown, a failure in either process is associated with oncogenic progression. Here, we show that VHL performs its FN‐associated function independently of the ECV complex, highlighting the autonomy of these pathways. Furthermore, we show that NEDD8, a ubiquitin‐like molecule, acts as a ‘molecular switch’ in which its covalent conjugation to VHL prohibits the engagement of the scaffold component CUL2 and, concomitantly, activates the association with FN. These findings provide the first mechanistic step in defining the functional selectivity of VHL and explain a previously unrecognized function of NEDD8.
Formation of a new receptor‐operated channel by heteromeric assembly of TRPP2 and TRPC1 subunits
Authors: Bai Chang‐Xi , Giamarchi Aurélie , Rodat‐Despoix Lise , Padilla Françoise , Downs Tamyra , Tsiokas Leonidas , Delmas Patrick
Published: March 2008

Although several protein–protein interactions have been reported between transient receptor potential (TRP) channels, they are all known to occur exclusively between members of the same group. The only intergroup interaction described so far is that of TRPP2 and TRPC1; however, the significance of this interaction is unknown. Here, we show that TRPP2 and TRPC1 assemble to form a channel with a unique constellation of new and TRPP2/TRPC1‐specific properties. TRPP2/TRPC1 is activated in response to G‐protein‐coupled receptor activation and shows a pattern of single‐channel conductance, amiloride sensitivity and ion permeability distinct from that of TRPP2 or TRPC1 alone. Native TRPP2/TRPC1 activity is shown in kidney cells by complementary gain‐of‐function and loss‐of‐function experiments, and its existence under physiological conditions is supported by colocalization at the primary cilium and by co‐immunoprecipitation from kidney membranes. Identification of the heteromultimeric TRPP2/TRPC1 channel has implications in mechanosensation and cilium‐based Ca2+ signalling.
G3 and density functional theory investigations of the structures and energies of SFnCl (n=–5) and their anions
Authors: Van Doren Jane M. , Miller Thomas M. , Viggiano A. A.
Published: March 2008

Computations of structures and total energies have been carried out for neutral and anionic SFnCl (n=0–5), using the composite G3 method and density functional theory (DFT) at the B3LYP∕6-311+G(3df) level. The total energies and zero-point energies have been used here to derive electron affinities, bond dissociation energies, and heats of formation. In addition, vibrational frequencies, polarizabilities, and dipole moments are reported. Results are compared with earlier work for SFm (m=1–6) and demonstrate how the relatively weak S–Cl bond and reduced symmetry influence the properties of these molecules and anions. Comparisons are also made between G3 and DFT results for SFnCl. Of particular interest is the alternating pattern of agreement between calculated electron affinity values with n. These calculations also provide critical energetic data needed to understand experimental measurements of electron attachment to SF5Cl [Van Doren et al., J. Chem. Phys. 128, 094309 (2008)] for which numerous ion products have been reported in the literature at low electron energy.