bluuebunny/crossref_metadata_2025 huggingface dataset:
Recombinant Glycans on an S‐Layer Self‐Assembly Protein: A New Dimension for Nanopatterned Biomaterials
Authors: Steiner Kerstin , Hanreich Angelika , Kainz Birgit , Hitchen Paul G. , Dell Anne , Messner Paul , Schäffer Christina
Published: September 2008

Crucial biological phenomena are mediated through carbohydrates that are displayed in a defined manner and interact with molecular scale precision. We lay the groundwork for the integration of recombinant carbohydrates into a “biomolecular construction kit” for the design of new biomaterials, by utilizing the self‐assembly system of the crystalline cell surface (S)‐layer protein SgsE of Geobacillus stearothermophilus NRS 2004/3a. SgsE is a naturally O‐glycosylated protein, with intrinsic properties that allow it to function as a nanopatterned matrix for the periodic display of glycans. By using a combined carbohydrate/protein engineering approach, two types of S‐layer neoglycoproteins are produced in Escherichia coli. Based on the identification of a suitable periplasmic targeting system for the SgsE self‐assembly protein as a cellular prerequisite for protein glycosylation, and on engineering of one of the natural protein O‐glycosylation sites into a target for N‐glycosylation, the heptasaccharide from the AcrA protein of Campylobacter jejuni and the O7 polysaccharide of E. coli are co‐ or post‐translationally transferred to the S‐layer protein by the action of the oligosaccharyltransferase PglB. The degree of glycosylation of the S‐layer neoglycoproteins after purification from the periplasmic fraction reaches completeness. Electron microscopy reveals that recombinant glycosylation is fully compatible with the S‐layer protein self‐assembly system. Tailor‐made (“functional”) nanopatterned, self‐assembling neoglycoproteins may open up new strategies for influencing and controlling complex biological systems with potential applications in the areas of biomimetics, drug targeting, vaccine design, or diagnostics.
Structural dominance analysis and theory building in system dynamics
Authors: Kampmann Christian Erik , Oliva Rogelio
Published: September 2008

We provide a review of different approaches to linking model structure to observed behaviour with a particular view towards using models for theory building. We argue that theory building cannot be based upon pure simulation and model building alone: the inference from system dynamics models invariably uses concepts and analogies from simple feedback systems and models. Strengthening the analytical foundation for this inference will therefore have a direct impact on the strength of system dynamics as a theory‐building tool. We identify four approaches to establish this link (traditional, pathway participation, eigenvalue and eigenvector), assess the strengths and weaknesses of each approach, and point to challenges and tasks ahead. We find that the eigenvalue and eigenvector approaches carry significant potential but that a more solid theoretical foundation of the method is required. However, since a ‘grand unified theory’ will never be possible, all tools will be based on approximations and it is only in their practical use that we can discover their real value. Copyright © 2008 John Wiley & Sons, Ltd.
Common learning and opportunistic behaviour in learning alliances
Authors: Kapmeier Florian
Published: September 2008

In this paper, we propose a system dynamics model that gives deeper insight into the dynamics involved in opportunistic behaviour in learning alliances. Although current research widely recognizes opportunistic behaviour of alliance partners as a reason for alliance failure, most research in this field focuses on opportunism in the area of private learning and of outlearning the partner. Opportunism is mostly ignored in situations of common learning. In the following, we study opportunism in alliances where there is no intention of learning privately. Moreover, in current studies, feedback perspectives are often neglected. A feedback perspective can be helpful to explain the reasons for certain unanticipated long‐term effects. We transfer findings from recent learning alliance literature and from a case study to a system dynamics simulation model. After describing the model structure, different scenarios offer insights into the dynamics of learning, particularly when the partners have different intentions with regard to common learning. We discuss the model runs and subsequently deduce propositions for future research. Copyright © 2008 John Wiley & Sons, Ltd.
Formal theory building for the avalanche game: explaining counter‐intuitive behaviour of a complex system using geometrical and human behavioural/physiological effects
Authors: Lane David C.
Published: September 2008

In ‘Avalanche’, an object is lowered, players staying in contact throughout. Normally the task is easily accomplished. However, with larger groups counter‐intuitive behaviours appear. The paper proposes a formal theory for the underlying causal mechanisms. The aim is to not only provide an explicit, testable hypothesis for the source of the observed modes of behaviour—but also to exemplify the contribution that formal theory building can make to understanding complex social phenomena. Mapping reveals the importance of geometry to the Avalanche game; each player has a pair of balancing loops, one involved in lowering the object, the other ensuring contact. For more players, sets of balancing loops interact and these can allow dominance by reinforcing loops, causing the system to chase upwards towards an ever‐increasing goal. However, a series of other effects concerning human physiology and behaviour (HPB) is posited as playing a role. The hypothesis is therefore rigorously tested using simulation. For simplicity a ‘One Degree of Freedom’ case is examined, allowing all of the effects to be included whilst rendering the analysis more transparent. Formulation and experimentation with the model gives insight into the behaviours. Multi‐dimensional rate/level analysis indicates that there is only a narrow region in which the system is able to move downwards. Model runs reproduce the single ‘desired’ mode of behaviour and all three of the observed ‘problematic’ ones. Sensitivity analysis gives further insight into the system's modes and their causes. Behaviour is seen to arise only when the geometric effects apply (number of players greater than degrees of freedom of object) in combination with a range of HPB effects. An analogy exists between the co‐operative behaviour required here and various examples: conflicting strategic objectives in organizations; Prisoners' Dilemma and integrated bargaining situations. Additionally, the game may be relatable in more direct algebraic terms to situations involving companies in which the resulting behaviours are mediated by market regulations. Finally, comment is offered on the inadequacy of some forms of theory building and the case is made for formal theory building involving the use of models, analysis and plausible explanations to create deep understanding of social phenomena. Copyright © 2008 John Wiley & Sons, Ltd.
Closing the loop: promoting synergies with other theory building approaches to improve system dynamics practice
Authors: Kopainsky Birgit , Luna‐Reyes Luis F.
Published: September 2008

This paper contributes to the development of better methods for the conceptualization of system dynamics models. It does so by looking at the model building process as a theory building process and by reviewing theory building approaches in other social sciences, such as grounded theory and case study research. Concepts of these modes of qualitative research constitute a tool set to build relevant system dynamics models, grounded in data, and with higher potential to provide rigorous and relevant generic structures. The deductive capability of simulation models, on the other hand, helps to close the loop in the theory building process, putting together the inductive and deductive stages in theory building. Copyright © 2008 John Wiley & Sons, Ltd.
First‐trimester screening in pregnancies conceived by assisted reproductive technology: significance of gestational dating by oocyte retrieval or sonographic measurement of crown–rump length
Authors: Gjerris A. C. , Loft A. , Pinborg A. , Tabor A. , Christiansen M.
Published: September 2008

Objectives

To evaluate, in pregnancies conceived by assisted reproductive technology, whether determination of gestational age (GA) by date of oocyte aspiration (DOA) or crown–rump length (CRL) at first‐trimester screening influences the distribution of serum and sonographic markers or the performance of first‐trimester screening for chromosomal abnormalities.

Methods

GA was calculated using either DOA or CRL at blood sampling and nuchal translucency thickness (NT) measurement in 729 singleton pregnancies conceived by in‐vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). Weight‐corrected log multiples of the median (MoM) marker distributions specific for IVF pregnancy were established using multiple log regression and compared for DOA‐ and CRL‐based GA calculation.

Results

GA determined by CRL was significantly larger, albeit slightly, than was GA determined by DOA, with a mean difference of 1.50 (SD, 2.4) days (P < 0.001). Log MoM distributions of free beta‐human chorionic gonadotropin and NT showed that GA dating by CRL resulted in significantly higher, albeit slightly, mean log MoM values compared with DOA dating. The reverse was the case for mean log MoM pregnancy‐associated plasma protein‐A. The SDs were similar for CRL and DOA dating. According to Monte Carlo simulation, the use of DOA or CRL for GA dating did not appreciably influence the performance of first‐trimester screening.

Conclusions

DOA and CRL are practically equivalent when calculating GA for first‐trimester screening. The correct method of GA dating for other purposes (e.g. estimated time of delivery) in IVF/ICSI pregnancies is still unresolved. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Use of transvaginal ultrasonography to predict preterm birth in women with a history of preterm birth
Authors: Crane J. M. G. , Hutchens D.
Published: September 2008

Objective

To investigate whether cervical length measured by transvaginal ultrasonography predicts spontaneous preterm birth at < 35 weeks' gestation in women with a history of spontaneous preterm birth, stratified by spontaneous preterm birth history subtype (preterm premature rupture of membranes (PPROM) or preterm labor with intact membranes at onset of labor).

Methods

This retrospective cohort study included women with a history of spontaneous preterm birth that were subsequently pregnant with singleton gestations, compared with a low‐risk control group. Transvaginal ultrasonographic cervical lengths were measured at 24 to 30 weeks of gestation. The primary outcome was spontaneous preterm birth at < 35 weeks. Secondary outcomes included spontaneous preterm birth at < 37 weeks and < 34 weeks, low birth weight, Cesarean delivery and perinatal morbidity and mortality. Multiple logistic regression analysis was used to control for potential confounders and calculate odds ratios and 95% confidence intervals. Receiver–operating characteristics (ROC) curves were used to determine the best cut‐off for transvaginal ultrasound cervical length in predicting spontaneous preterm birth at < 35 weeks.

Results

Women with a history of spontaneous preterm birth with intact membranes at onset of labor (n = 42) had a shorter cervical length (3.28 cm) than women with a history of spontaneous preterm birth with PPROM at onset of labor (n = 48, cervical length 3.77 cm; P = 0.019), and both subgroups had shorter cervical lengths than the low‐risk control group (n = 103, cervical length 4.30 cm; P < 0.0001). Both subgroups were associated with spontaneous preterm birth at < 35 weeks, < 37 weeks, < 34 weeks and birth weight < 2500 g. ROC curves determined that the best cut‐off for cervical length to predict spontaneous preterm birth at < 35 weeks was 3.0 cm. By multiple logistic regression analysis, the only independent predictors of spontaneous preterm birth at < 35 weeks were cervical length < 3.0 cm, a history of spontaneous preterm birth and antepartum bleeding in the current pregnancy. In women with a history of spontaneous preterm birth, a cervical length as measured by transvaginal ultrasonography of < 3.0 cm had a sensitivity of 63.6%, specificity of 77.2%, positive predictive value of 28.0% and negative predictive value of 93.8%, for preterm birth at < 35 weeks.

Conclusion

Women with a history of spontaneous preterm birth with preterm labor and intact membranes at the onset of labor have shorter cervices than women with a history of spontaneous preterm birth and PPROM at the onset of labor, and both groups have shorter cervices than a low‐risk control group. Both groups of women with a history of spontaneous preterm birth have an increased risk of recurrent spontaneous preterm birth at < 35 weeks, and this is predicted by a transvaginal ultrasound cervical length of < 3.0 cm. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Fetal celiac and splenic artery flow velocity and pulsatility index: longitudinal reference ranges and evidence for vasodilation at a low portocaval pressure gradient
Authors: Ebbing C. , Rasmussen S. , Godfrey K. M. , Hanson M. A. , Kiserud T.
Published: September 2008

Objectives

To establish longitudinal reference ranges for the fetal celiac and splenic arteries flow velocity and pulsatility index (PI), and to determine their hemodynamic relationship to venous liver perfusion and distribution and to other essential arteries.

Methods

This was a prospective longitudinal study of 161 low‐risk pregnancies. Doppler recordings of the celiac and splenic arteries were made on three to five occasions at 3–5‐week intervals to establish reference ranges for blood velocity and PI measurements. Peak systolic velocity in the ductus venosus, a shunt between the umbilical and inferior caval veins, was used to represent the umbilicocaval (i.e. portocaval) pressure gradient, and the left portal vein blood velocity represented the umbilical distribution to the right liver lobe. The correlations between the celiac, splenic and hepatic arteries were determined, and their association with the middle cerebral and umbilical artery PIs (MCA‐PI and UA‐PI) was assessed.

Results

Longitudinal reference ranges for the fetal celiac and splenic arteries were established based on 510 and 521 observations, respectively, during gestational weeks 21–39. Terms for calculating conditional reference ranges to be used for repeat observations are provided. Celiac and splenic artery PIs were low when portocaval pressure and umbilical supply to the right lobe were low (P< 0.0001). Their peak systolic velocity and PI were correlated (r= 0.7 (95% CI, 0.6–0.8) andr= 0.5 (95% CI, 0.3–0.6), respectively), while the PI of the hepatic artery correlated weakly with those of the celiac and splenic arteries. They were positively associated with the MCA‐PI and UA‐PI (P< 0.0001).

Conclusion

We provide longitudinal reference ranges for the fetal celiac and splenic arteries Doppler measurements and show that they are involved in maintaining portal liver perfusion independently from the hepatic artery. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Efficient call admission control scheme for 4G wireless networks
Authors: Tarek Bejaoui , Nidal Nasser
Published: September 2008

Next generation wireless networks (NGWNs) will utilize several different radio access technologies, seamlessly integrated to form one access network. This network has the potential to provide many of the requirements that other previous systems did not achieve such as high data transfer rates, effectives user control, seamless mobility, and others which will potentially change the way users utilize mobile devices. NGWN will integrate a multitude of different heterogeneous networks including (a) cellular networks, passed through multiple generations—1G, 2G, 3G, and 3.5G; (b) wireless LANs, championed by the IEEE 802.11 wireless fidelity (WiFi) networks; and (c) broadband wireless access networks (IEEE 802.16, WiMAX). In this paper, a new adaptive quality of service (QoS) oriented CAC scheme is proposed to limit the occurrence of hard IEEE 802.11 WLAN‐UMTS handovers to mobile users using real time (RT) applications. This scheme is hybrid, based on the service class differentiation, the location in the heterogeneous infrastructure and a vertical handoff decision function as well. Simulation results show that our policy achieves significant performance gains. It maximizes the utilization of the resources available at the WLAN cells, and meets as much as possible the QoS requirement of higher priority users. Copyright © 2008 John Wiley & Sons, Ltd.
Cross‐layer optimization for energy‐efficient wireless communications: a survey
Authors: Miao Guowang , Himayat Nageen , Li Ye (Geoffrey) , Swami Ananthram
Published: September 2008

Since battery technology has not progressed as rapidly as semiconductor technology, power efficiency has become increasingly important in wireless networking, in addition to the traditional quality and performance measures, such as bandwidth, throughput, and fairness. Energy‐efficient design requires a cross layer approach as power consumption is affected by all aspects of system design, ranging from silicon to applications. This article presents a comprehensive overview of recent advances in cross‐layer design for energy‐efficient wireless communications. We particularly focus on a system‐based approaches toward energy optimal transmission and resource management across time, frequency, and spatial domains. Details related to energy‐efficient hardware implementations are also covered. Copyright © 2008 John Wiley & Sons, Ltd.
Offshore wind profiling using light detection and ranging measurements
Authors: Peña Alfredo , Hasager Charlotte Bay , Gryning Sven‐Erik , Courtney Michael , Antoniou Ioannis , Mikkelsen Torben
Published: September 2008

The advantages and limitations of the ZephIR®, a continuous‐wave, focused light detection and ranging (LiDAR) wind profiler, to observe offshore winds and turbulence characteristics were tested during a 6 month campaign at the transformer/platform of Horns Rev, the world's largest wind farm. The LiDAR system is a ground‐based sensing technique which avoids the use of high and costly meteorological masts. Three different inflow conditions were selected to perform LiDAR wind profiling. Comparisons of LiDAR mean wind speeds against cup anemometers from different masts showed high correlations for the open sea sectors and good agreement with their longitudinal turbulence characteristics. Cup anemometer mean wind speed profiles were extended with LiDAR profiles up to 161 m on each inflow sector. The extension resulted in a good profile match for the three surrounding masts. These extended profiles, averaged over all observed stabilities and surface roughness lengths, were compared to the logarithmic profile. The observed deviations were relatively small. Offshore wind farm wakes were also observed from LiDAR measurements where the wind speed deficits were detected at all LiDAR heights. Profile‐derived friction velocities and roughness lengths were compared to Charnock's sea roughness model. These average values were found to be close to the model, although the scatter of the individual estimations of sea roughness length was large. Copyright © 2008 John Wiley & Sons, Ltd.
Determination of the composition of Ultra‐thin Ni‐Si films on Si: constrained modeling of electron probe microanalysis and x‐ray reflectivity data
Authors: Phung Tran M. , Jensen Jacob M. , Johnson David C. , Donovan John J. , McBurnett Brian G.
Published: September 2008

The homogeneous bulk assumption used in traditional electron probe microanalysis (EPMA) can be applied for thin‐layered systems with individual layers as thick as 50 nm provided the penetration depth of the lowest accelerating voltage exceeds the total film thickness. Analysis of an NIST Ni‐Cr thin film standard on Si using the homogeneous model yielded certified compositions and application of the same model to ultra‐thin Ni‐Si layers on GaAs yielded their expected compositions. In cases where the same element is present in multiple layers or in the substrate as well as the film, the homogeneous assumption in EPMA alone is not sufficient to determine composition. By combining x‐ray reflectivity (XRR) thickness and critical angle data and using an iterative approach, quantitative compositional data in EPMA can be achieved. This technique was utilized to determine the composition of Ni‐Si ultra‐thin films grown on silicon. The Ni‐Si composition determined using this multi‐instrumental technique matched that of Ni‐Si films simultaneously deposited on GaAs. Copyright © 2008 John Wiley & Sons, Ltd.
Structural and electronic effects in metallocene catalysts studied by x‐ray techniques
Authors: Silveira Fernando , de Sá Denise Santos , da Rocha Zênis Novais , do Carmo Martins Alves Maria , dos Santos João Henrique Zimnoch
Published: September 2008

A series of metallocenes, namely, [Cp2ZrCl2], [(MeCp)2ZrCl2], [(nBuCp)2ZrCl2], [(iBuCp)2ZrCl2], [(tBuCp)2ZrCl2], [Et(Ind)2ZrCl2], [Et(IndH4)2ZrCl2], and [MeSi2(Ind)2ZrCl2)] were analyzed by extended x‐ray absorption fine structure (EXAFS) and x‐ray photoelectron spectroscopy (XPS). Complementary techniques, UV–vis spectroscopy and cyclic and differential pulse voltammetry, were employed to characterize the organometallic complexes. The catalysts were evaluated in ethylene polymerization, having methylaluminoxane (MAO) as the cocatalyst, and the resulting polymers were characterized by gel permeation chromatography. The structural and electronic effects caused by the coordination sphere around the metal center and their effects on the catalytic activity and polymer characteristics are discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Origin of Capacity Fading in Nano-Sized Co3O4Electrodes: Electrochemical Impedance Spectroscopy Study
Authors: Kang Jin-Gu , Ko Young-Dae , Park Jae-Gwan , Kim Dong-Wan
Published: September 2008

Transition metal oxides have been suggested as innovative, high-energy electrode materials for lithium-ion batteries because their electrochemical conversion reactions can transfer two to six electrons. However, nano-sized transition metal oxides, especially Co3O4, exhibit drastic capacity decay during discharge/charge cycling, which hinders their practical use in lithium-ion batteries. Herein, we prepared nano-sized Co3O4with high crystallinity using a simple citrate-gel method and used electrochemical impedance spectroscopy method to examine the origin for the drastic capacity fading observed in the nano-sized Co3O4anode system. During cycling, AC impedance responses were collected at the first discharged state and at every subsequent tenth discharged state until the 100th cycle. By examining the separable relaxation time of each electrochemical reaction and the goodness-of-fit results, a direct relation between the charge transfer process and cycling performance was clearly observed.
Tibial tuberosity fractures in adolescents
Authors: Frey Steven , Hosalkar Harish , Cameron Danielle B. , Heath Aaron , David Horn B. , Ganley Theodore J.
Published: September 2008

Background

Tibial tuberosity fractures in adolescents are uncommon. We retrospectively reviewed all tibial tuberosity fractures in adolescents (10–19) who presented to our level 1 pediatric trauma center over a 7-year period to review fracture morphology, mechanism of injury, fracture management including return to play, as well as complications. Additionally, we present a review of the literature and treatment algorithm.

Methods

We reviewed the clinical charts and radiographs of consecutive patients with tibial tuberosity fractures between 01 January 2000 and 01 January 2007. Data parameters included the following: patients age and gender, involved side, injury classification, co-morbidities, mechanism of injury, treatment, return to activity and complications. Data were extracted and reviewed, and a treatment algorithm is proposed with some additional insights into the epidemiology of the injury. Nineteen patients met the inclusion criteria.

Results

There were 19 patients with 20 tibial tuberosity fractures. The mean age was 13.7 years. There were 18 males and 1 female patient. There were nine left-sided injuries and eleven right-sided including one patient with bilateral fractures. Mechanism of injuries included basketball injury (8), running injury (5), football injury (3), fall from a scooter (2), high jump (1) and fall (1). Co-morbidities included three patients with concurrent Osgood–Schlatter disease and one with osteogenesis imperfecta. All were treated with ORIF, including arthroscopic-assisted techniques in two cases. Complications included four patients with pre-operative presentation of compartment syndrome all requiring fasciotomy, one post-operative stiffness and one painful hardware requiring removal. Range of motion was started an average of 4.3 weeks post-operatively and return to play was an average of 3.9 months post-operatively.

Conclusion

Although uncommon, tibial tuberosity fractures in adolescents are clinically important injuries. Early recognition and treatment (closed or open as appropriate) gives good results. All the patients in our series had surgical fixation as per different indications that have been elaborated. It is important for clinicians to recognize that compartment syndrome remains a significant concern post-injury and in the perioperative period. Close monitoring and timely intervention is recommended. A simple treatment algorithm is presented for clinicians to help manage these injuries.
Sexual violence‐related fistulas in the Democratic Republic of Congo
Authors: Onsrud Mathias , Sjøveian Solbjørg , Luhiriri Roger , Mukwege Dennis
Published: September 2008

Objective

To determine the magnitude of traumatic gynecologic fistulas caused by sexual violence in the Democratic Republic of Congo.

Methods

A retrospective analysis of hospital records from 604 consecutive patients who received treatment for gynecologic fistulas at Panzi Hospital between November 2005 and November 2007.

Results

Of the 604 patients, 24 (4%) reported that their fistulas had been caused by sexual violence; of these, 5 (0.8%) had developed fistulas as a direct result of forced penetration with foreign objects and/or gang rapes. Of the remaining patients, 6 had a fistula before they were raped, 9 developed iatrogenic fistulas following inappropriate instrumentation to manage rape‐induced spontaneous abortion or stillbirth, or after abdominal hysterectomy, and 4 developed fistulas after prolonged and obstructed labor.

Conclusion

Traumatic fistulas are rare compared to obstetric fistulas. Fistulas indirectly related to sexual violence are likely to be more common than those directly related. All fistulas resulting from sexual violence, whether direct or indirect, should be considered traumatic and special care should be given to these women.
‘THESE LAWS SHOULD BE MADE BY US’: CUSTOMARY MARRIAGE LAW, CODIFICATION AND POLITICAL AUTHORITY IN TWENTIETH-CENTURY COLONIAL GABON
Authors: JEAN-BAPTISTE RACHEL
Published: September 2008

This article analyzes the multiple and failed efforts to codify customary marriage law over the course of the twentieth century in colonial Gabon. It argues that these efforts illuminate the discursive arenas in which the colonial state, the church and African political leaders struggled to demarcate power and control over wealth-in-women. In a time of sociopolitical crisis and change state, chiefs and other elite African men all become involved in attempts to conceptualize, codify and administer customary marriage law. The contested process of codification reveals disjunctures in the articulation of male political authority in colonial Gabon.
NETWORKS OF KNOWLEDGE: CLANSHIP AND COLLECTIVE WELL-BEING IN BUGANDA
Authors: KODESH NEIL
Published: September 2008

This article raises the question of how scholars might make sense of well-known components of social organization in Africa in the absence of the increasingly criticized evolutionary and lineage models that once gave them meaning. In an effort to understand why our earliest glimpses into the distant Ganda past appear in the form of clan histories, the article examines the relationship between clanship, public healing and transformations in agricultural practices. Beginning around the fifteenth and sixteenth centuries, Ganda expanded upon earlier knowledge of banana cultivation to develop a land-intensive banana farming system. This process coincided with the transformation of previously territorial spirits into portable spirits capable of ensuring the health of disconnected groups of people. At the heart of these undertakings stood the ideology and practices of clanship, which furnished the conceptual bridge connecting transformations in agriculture and public healing. The webs of shrines situated on discontiguous clan lands created therapeutic networks that drew together communities whose leaders possessed a variety of skills, thus forging a powerful connection between clanship, collective health and the composition of knowledge.
‘TO NEVER SHED BLOOD’: YACOUBA SYLLA, FÉLIX HOUPHOUËT-BOIGNY AND ISLAMIC MODERNIZATION IN CÔTE D'IVOIRE
Authors: HANRETTA SEAN
Published: September 2008

After an ill-fated religious revival, the Sufi teacher Yacouba Sylla and his followers became wealthy and politically influential in post-Second World War Côte d'Ivoire. They argued for an understanding of democratization and development that defined both ideas in terms of their community's own mystical experiences and world-historical significance, rather than in terms of modernity. As a way of making sense of their own past and defending their place in an increasingly tense political environment, these efforts achieved their most explicit articulation in a powerful story about Yacouba Sylla's refusal of a gift from Ivoirian President Félix Houphouët-Boigny.
HISTORY, MEMORY AND THE LEGACY OF SAMORI IN SOUTHERN MALI, c. 1880–1898
Authors: PETERSON BRIAN J.
Published: September 2008

This article seeks to situate local oral traditions on Samori Touré within the contexts of both internal African empire building and French colonial conquest. It takes into account the experiences of the vanquished on the periphery of Samori's empire in an effort to reassess his legacy. It argues that local traditions not only provide a corrective to the nationalist historiography on Samori, they also complicate the notion of ‘resistance’ by demonstrating internal dissent and even rebellion against Samorian rule at a time of Samori's vaunted ‘primary resistance’ to French conquest. Finally, this article concludes by providing a contemporary reading of the southern Malian historical landscape, rooting local Samorian history and politics in particular ‘sites of memory’.
POSSIBILITY AND CONSTRAINT: AFRICAN INDEPENDENCE IN HISTORICAL PERSPECTIVE
Authors: COOPER FREDERICK
Published: September 2008

On the fiftieth anniversary of an ambiguous event – the referendum giving French Africans the choice of immediate independence or a new status within a ‘French Community’ – this article points to the alternative forms of political action which opened up at certain moments in African history and how, at other moments, some of those alternatives closed down. It assesses concepts, issues and arguments used in writing the history of Africa, now that the recent African past – spanning the last years of colonial rule and the years of independence – is becoming a focus of historical inquiry.
Magnitude and contributory factors of postnatal depression: a community-based cohort study from a rural subdistrict of Bangladesh
Authors: Gausia K. , Fisher C. , Ali M. , Oosthuizen J.
Published: September 2008

Background

Recent evidence suggests that the prevalence of postnatal depression (PND) is highest in low-income developing countries. This study aimed to estimate the prevalence of PND and its associated risk factors among Bangladeshi women.

Method

The study was conducted in the Matlab subdistrict of rural Bangladesh. A cohort of 346 women was followed up from late pregnancy to post-partum. Sociodemographic and other related information on risk factors was collected on structured questionnaires by trained interviewers at 34–35 weeks of pregnancy at the woman's home. A validated local language (Bangla) version of the Edinburgh Postnatal Depression Scale (EPDS-B) was used to measure depression status at 34–35 weeks of pregnancy and at 6–8 weeks after delivery.

Results

The prevalence of PND was 22% [95% confidence interval (CI) 17.7–26.7%] at 6–8 weeks post-partum. After adjustment in a multivariate logistic model, PND could be predicted by history of past mental illness [odds ratio (OR) 5.6, 95% CI 1.1–27.3], depression in current pregnancy (OR 6.0, 95% CI 3.0–12.0), perinatal death (OR 14.1, 95% CI 2.5–78.0), poor relationship with mother-in-law (OR 3.6, 95% CI 1.1–11.8) and either the husband or the wife leaving home after a domestic quarrel (OR 4.0, 95% CI 1.6–10.2).

Conclusions

The high prevalence of PND in the study was similar to other countries in the South Asian region. The study findings highlight the need for programme managers and policy makers to allocate resources and develop strategies to address PND in Bangladesh.
Bacterial flagellar motor
Authors: Sowa Yoshiyuki , Berry Richard M.
Published: September 2008

The bacterial flagellar motor is a reversible rotary nano-machine, about 45 nm in diameter, embedded in the bacterial cell envelope. It is powered by the flux of H+or Na+ions across the cytoplasmic membrane driven by an electrochemical gradient, the proton-motive force or the sodium-motive force. Each motor rotates a helical filament at several hundreds of revolutions per second (hertz). In many species, the motor switches direction stochastically, with the switching rates controlled by a network of sensory and signalling proteins. The bacterial flagellar motor was confirmed as a rotary motor in the early 1970s, the first direct observation of the function of a single molecular motor. However, because of the large size and complexity of the motor, much remains to be discovered, in particular, the structural details of the torque-generating mechanism. This review outlines what has been learned about the structure and function of the motor using a combination of genetics, single-molecule and biophysical techniques, with a focus on recent results and single-molecule techniques.
Protein–protein interaction and quaternary structure
Authors: Janin Joël , Bahadur Ranjit P. , Chakrabarti Pinak
Published: September 2008

Protein–protein recognition plays an essential role in structure and function. Specific non-covalent interactions stabilize the structure of macromolecular assemblies, exemplified in this review by oligomeric proteins and the capsids of icosahedral viruses. They also allow proteins to form complexes that have a very wide range of stability and lifetimes and are involved in all cellular processes. We present some of the structure-based computational methods that have been developed to characterize the quaternary structure of oligomeric proteins and other molecular assemblies and analyze the properties of the interfaces between the subunits. We compare the size, the chemical and amino acid compositions and the atomic packing of the subunit interfaces of protein–protein complexes, oligomeric proteins, viral capsids and protein–nucleic acid complexes. These biologically significant interfaces are generally close-packed, whereas the non-specific interfaces between molecules in protein crystals are loosely packed, an observation that gives a structural basis to specific recognition. A distinction is made within each interface between a core that contains buried atoms and a solvent accessible rim. The core and the rim differ in their amino acid composition and their conservation in evolution, and the distinction helps correlating the structural data with the results of site-directed mutagenesis andin vitrostudies of self-assembly.
Dosierungsbesonderheiten am Anfang und Ende einer Therapie
Authors: Haefeli Walter E. , Walter-Sack Ingeborg
Published: September 2008

Die Dosis, mit der eine Therapie begonnen wird, bestimmt nicht nur deren Wirkungseintritt, sondern oft auch deren Verträglichkeit. Während die meisten Therapien akut mit üblichen Erhaltungsdosen begonnen werden dürfen, sollten Substanzen mit ausgeprägter Autoinduktion (z.B. Carbamazepin) einschleichend dosiert werden, da die geringe Abbaurate zu Beginn der Therapie sonst zur Akkumulation und Überdosierungserscheinungen führt. Ebenfalls einschleichend muss dosiert werden, wenn durch die Therapie erhebliche pharmakodynamische Adaptationsvorgänge angestoßen werden. Dies ist oft mit dem Risiko überschießender unerwünschter Ereignisse verbunden (z.B. kardiale Dekompensation zu Beginn der β-Blockade bei Herzinsuffizienz); auch hier muss einschleichend dosiert und vorsichtig gesteigert werden. Solche Arzneimittel sollten nach mehrwöchiger Therapie nur vorsichtig wieder abgesetzt werden, um zum Teil lebensbedrohliche Entzugssyndrome wie hypertensive Krisen nach Clonidin- Entzug oder Entzugsanfälle nach Absetzen von Antikonvulsiva zu verhindern.
Chronische systolische Herzinsuffizienz – Arzneimittel-Dosierung am Anfang und Ende einer Therapie
Authors: Zugck Christian , Remppis Andrew , Katus Hugo A. , Frankenstein Lutz
Published: September 2008

Das «Syndrom Herzinsuffizienz» und die damit verbundene Komplexität einer multimodalen Therapie machen es zu einer echten Herausforderung den Patienten mit (fortgeschrittener) Herzinsuffizienz leitliniengerecht zu therapieren. Außerdem ist die in den letzten Jahren erreichte Mortalitäts- und Morbiditätsreduktion im Wesentlichen abhängig von einer konsequenten – über Wochen sich hinziehenden – Umsetzung des empfohlenen Therapie-Regimes. Dieser Artikel gibt eine Leitlinienkonforme Übersicht zum praktischen Management am Anfang und Ende einer Therapie bei Patienten mit einer chronischen systolischen Herzinsuffizienz.
Ein- und Ausschleichen von Psychopharmaka – Empfehlungen zur Depressionsbehandlung
Authors: Bienentreu Sara , Külkens Sonja , Mundt Christoph
Published: September 2008

Kenntnisse der Diagnostik und Therapie depressiver Erkrankungen sind für jeden Arzt wegen der Häufigkeit der Erkrankungen von großer Bedeutung. Insbesondere der Beginn und die Beendigung einer antidepressiven Therapie stellen kritische Phasen der Behandlung dar, in welchen aufgrund möglicher Nebenwirkungen bzw. Absetzphänomene ein enger Kontakt zum Patienten notwendig ist. Der folgende Artikel gibt einen Überblick über die verschiedenen Antidepressiva sowie Empfehlungen für das Ein- und Ausschleichen der Medikation, zumeist aus der klinischen Erfahrung heraus, da keine evidenzbasierten Schemata vorliegen.
Ein- und Ausschleichen von Analgetika – Empfehlungen zur Schmerztherapie
Authors: Busch Cornelius J. , Bardenheuer Hubert J.
Published: September 2008

Die Therapie von Schmerzen gehört zu den Basisaufgaben eines klinisch tätigen Arztes. Gute Kenntnis des Wirkprofils der dazu verwendeten Analgetika sowie ihrer Nebenwirkungen erleichtern den Einsatz und mindern unerwünschte Wirkungen. Der folgende Artikel soll einen kurzen Überblick über gebräuchliche Analgetika sowie einen Anhalt für deren Anwendung und Dosierung zu Beginn und Ende einer Therapie geben.
Hyporheic flows in stratified beds
Authors: Marion Andrea , Packman Aaron I. , Zaramella Mattia , Bottacin‐Busolin Andrea
Published: September 2008

Surface‐subsurface exchange fluxes are receiving increasing interest because of their importance in the fate of contaminants, nutrients, and other ecologically relevant substances in a variety of aquatic systems. Solutions have previously been developed for pore water flows induced by geometrical irregularities such as bed forms for the cases of homogeneous sediment beds and idealized heterogeneous beds, but these solutions have not accounted for the fact that streambed sediments are subject to sorting processes that often produce well‐defined subsurface structures. Sediments at the streambed surface are often coarser than the underlying material because of size‐selective sediment transport, producing relatively thin armor layers. Episodic erosional and depositional processes also create thick layers of different composition within the porous medium, forming stratified beds. A series of experiments were conducted to observe conservative solute transport in armored and stratified beds. An analytical solution was developed for advective exchange with stratified beds and provides appropriate scaling of the physical variables that control exchange flows. The results show that armor layers are too thin to significantly alter the advective pumping process but provide significant solute storage at short time scales. Stratified beds with layers of significant thickness favor development of horizontal flow paths within the bed and change the rate of solute transfer across the stream‐subsurface interface compared to homogeneous beds.
Applying bootstrap resampling to quantify uncertainty in fluvial suspended sediment loads estimated using rating curves
Authors: Rustomji P. , Wilkinson S. N.
Published: September 2008

Knowledge of suspended sediment loads in rivers is essential for catchment management purposes and study of landscape evolution. Obtaining such information is difficult because of the often sparse physical sampling of sediment concentrations and high temporal variability in discharge and sediment concentration, as well as strong hysteretic effects and temporal and spatial variations in catchment condition. Here bootstrap and Monte Carlo resampling techniques are used to calculate suspended sediment loads using sediment rating curves. The method proposed avoids the need to apply a bias correction factor to load estimates calculated using rating curves defined by least squares regression of log‐transformed data. The algorithm also quantifies uncertainty in suspended sediment load estimates arising from uncertainty in the shape of the rating curve and the residual scatter in the data. Applied to 11 gauging stations in the catchment of Lake Burragorang in Australia, the method produced suspended sediment yields consistent with other Australian observations. The majority of the sediment delivered to the lake comes via the lower Wollondilly River (251−49+264 kt a−1), with lesser contributions from the Kowmung (114−30+62 kt a−1) and Cox's (63−14+81 kt a−1) rivers. Despite uncertainty in the shape of the rating curve at high flows, days with the largest flow clearly transport most of the suspended sediment delivered to the reservoir over the long term, with 40–85% of the total load being transported in <1% of the time. This bootstrap‐based method could be applied to the calculation of other constituent fluxes in rivers where discrete sampling of constituent concentration serves as the principal data.
False causality between Atlantic hurricane activity fluctuations and seasonal lower atmospheric wind anomalies
Authors: Swanson Kyle L.
Published: September 2008

Statistical studies suggest a link between anomalies in seasonally averaged lower atmospheric dynamical fields and Atlantic hurricane activity. Here we show that lower atmospheric seasonal wind anomalies result primarily from the presence of the hurricanes themselves. This is done by assuming a hypothetical vortex structure whose radial structure is constrained by observations derived from aircraft probing of tropical cyclones and whose vorticity magnitude is scaled to time varying, best track intensities. Seasonal vorticity anomalies associated with Atlantic hurricane activity are accumulated by summing these idealized vorticities along observed tropical cyclone tracks. Winds associated with these seasonal vorticity anomalies explain the bulk of observed hurricane activity‐related fluctuations in the seasonally averaged lower tropospheric wind. Hence, seasonal wind anomalies appear to have little causal information relevant to understanding why hurricane activity in the Atlantic has fluctuated in the past, and may be of limited value in projecting future hurricane activity.
Sea surface temperature differences between the western equatorial Pacific and northern South China Sea since the Pliocene and their paleoclimatic implications
Authors: Jia Guodong , Chen Fajin , Peng Ping'an
Published: September 2008

Alkenone sea surface temperatures (SSTs) in the northern South China Sea (SCS) were reconstructed for the last ∼3.8 Ma. The SST difference between the western equatorial Pacific and northern SCS was then estimated, showing a general increase since ∼2.8 Ma. Three features of the SST‐gradient evolution were prominent: 1) low values (<2°C) in the late Pliocene; 2) increased values during the late Pliocene/early Pleistocene (from 1 to 4°C); and 3) high values (∼4°C) by the end of the early Pleistocene. These features were also shown in zonal SST gradient across equatorial Pacific, implying an intimate relationship of the meridional Hadley and East Asian monsoon circulations with the zonal Walker circulation. Moreover, the SST gradient records displayed some characters unique to the equatorial Pacific and not found in benthic δ18O record, suggesting that zonal tropical climate change could spread into higher latitude by interactions with meridional circulations.
A comet‐like escape of ionospheric plasma from Mars
Authors: Lundin R. , Barabash S. , Holmström M. , Nilsson H. , Yamauchi M. , Fraenz M. , Dubinin E. M.
Published: September 2008

New measurements of the ion escape from Mars display a mantle of low‐energy ionospheric ions swept from the dayside over the terminator, expanding into the tail in a comet‐like fashion. The finding is based on data obtained with new energy settings for the ASPERA‐3 ion mass analyzer (IMA), enabling us to also measure cold ionospheric ions. By including the comet‐like contribution of low‐energy ions (<200 eV), we obtain a heavy ion escape rate of 3.3 · 1024 (±0.6 · 1024) s−1. While a modest energization characterizes the draped comet‐like outflow of low‐energy ions, ion pickup and acceleration above magnetic anomalies leads to the energetic and structured ion fluxes observed in the Martian tail. Compared to the previous measurements, where the flow of accelerated ionospheric ions is asymmetric, controlled by the solar wind electric field, the low‐energy ion escape is symmetric, emerging from the dayside and expanding towards the tail along the tail flank. An analysis of the escape rate versus tail distance from the planet displays a gradual energization of ions, yet maintaining an almost constant escape rate. We finally note that the planetary heavy ion escape rate is measured during solar minimum. The solar maximum value is yet to be determined, but it may very well exceed 1025 ions/s.
Differences in the non‐stationary influence of the North Atlantic Oscillation on European precipitation under different scenarios of greenhouse gas concentrations
Authors: Vicente‐Serrano S. M. , López‐Moreno J. I.
Published: September 2008

The changing spatial patterns of the North Atlantic Oscillation (NAO) dipole and the changing correlations between the NAO and European precipitation were analyzed using the AOGCM CGCM3.1(T63) model provided by the Canadian Centre for Climate Modelling and Analysis (CCCma). Four output scenarios were considered: the IPCC pre‐industrial (PI) scenario, the 20th century (20C) scenario, and the B1 and A2 emission scenarios for the 21st century. We detected some differences in the spatial patterns of the NAO‐precipitation relationship among the four scenarios. Moreover, there were large differences in the temporal stability of the NAO pressure pattern, and also in the NAO‐precipitation relationship among the four scenarios. Under increased greenhouse gas emissions the stability of the NAO‐precipitation correlations is enhanced due to the lower variability in the pattern of the NAO dipole.