bluuebunny/crossref_metadata_2025 huggingface dataset:
Is chorionic villus sampling associated with hypertensive disorders of pregnancy?
Authors: Odibo Anthony O. , Singla Ashima , Gray Diana L. , Dicke Jeffrey M. , Oberle Barbara , Crane James
Published: November 2009

Objective

Our objective is to evaluate for potential associations between chorionic villus sampling (CVS) and hypertensive disorders of pregnancy.

Methods

Using our genetic database, we compared the rates of hypertensive disorders between women who underwent CVS at 10–13 and 6/7 weeks with those seen for other indications at similar gestational ages who had no invasive procedure. Only singleton and euploid pregnancies were included. Statistical methods including univariable and multivariable logistic regression, supplemented by stratified analyses were used for comparisons.

Results

Among 11 012 pregnant women seen between 1990 and 2006 in our center and meeting the inclusion criteria, information on hypertensive disorders of pregnancy were available in 9386, and 9098 met the inclusion criteria. The overall incidence of hypertensive disorders was 421/9098 (4.6%), with 138/5096 (2.7%) in the CVS group and 283/4002 (7.1%) in the control group [adjusted odds ratio (adjOR) 0.47, 95% confidence interval (CI), 0.38–0.59]. Similar findings were seen on stratified analyses for gestational age of procedure and the type or severity of hypertensive disorder, and other potential confounders.

Conclusion

The rate of hypertensive disorders of pregnancy is significantly lower in women having CVS compared with the control group. Placental disruption from CVS is not associated with preeclampsia or gestational hypertension. Copyright © 2009 John Wiley & Sons, Ltd.
A combined experimental and theoretical study of benzoxaborole derivatives by Raman and IR spectroscopy, static DFT, and first‐principle molecular dynamics
Authors: Jezierska Aneta , Panek Jarosław J. , Żukowska Grażyna Z. , Sporzyński Andrzej
Published: November 2009

Physicochemical properties of 1,3‐dihydro‐1‐hydroxy‐3‐morpholin‐4‐yl‐2,1‐benzoxaborole (IIa) and 1,3‐dihydro‐1‐ hydroxy‐2,1‐benzoxaborole (IIb) were investigated using a combination of spectroscopic and computational approaches. The compoundIIabelongs to the group represented by the prototypical benzoxaboroleIIb, which exhibits receptor activity toward sugars in aqueous solution. Additionally, theIIbcan serve as a pattern structure for physicochemical description of benzoxaborole derivatives. The infrared and Raman spectroscopy measurements were performed in solvents and in the solid state. Furthermore, experimental findings served as a reference data source for further computational investigations. DFT calculationsin vacuowere used to estimate the binding energy of the dimeric forms, indicating the strength of the intermolecular hydrogen bonds. AIM and ELF theories were applied to give an insight into the electronic structure of the studied compounds. The last part of this study contains Car–Parrinello molecular dynamics investigations in the solid state. Computational results indicated that the key intermolecular feature, the pair of hydrogen bonds, is rather harmonic and the extent of the anharmonicity is temperature dependent as shown by the OH stretching envelope calculations performed forIIa. Inclusion of the quantum effects in the proton motion does not significantly change the qualitative description of the intermolecular H‐bond dynamics of the investigated compound. Copyright © 2010 John Wiley & Sons, Ltd.
Excited‐state lifetime studies of the three tryptophan residues in the N‐lobe of human serum transferrin
Authors: James Nicholas G. , Ross Justin A. , Mason Anne B. , Jameson David M.
Published: November 2009

The energy transfer from the three Trp residues at positions 8, 128, and 264 within the human serum transferrin (hTF) N‐lobe to the ligand to metal charge transfer band has been investigated by monitoring changes in Trp fluorescence emission and lifetimes. The fluorescence emission from hTF N‐lobe is dominated by Trp264, as revealed by an 82% decrease in the quantum yield when this Trp residue is absent. Fluorescence lifetimes were determined by multifrequency phase fluorometry of mutants containing one or two Trp residues. Decays of these samples are best described by two or three discrete lifetimes or by a unimodal Lorentzian distribution. The discrete lifetimes and the center of the lifetime distribution for samples containing Trp128 and Trp264 are affected by iron. The distribution width narrows on iron removal and is consistent with a decrease in dynamic mobility of the dominant fluorophore, Trp264. Both the quantum yield and the lifetimes are lower when iron is present, however, not proportionally. The greater effect of iron on quantum yields is indicative of nonexcited state quenching, i.e., static quenching. The results of these experiments provide quantitative data strongly suggesting that Förster resonance energy transfer is not the sole source of Trp quenching in the N‐lobe of hTF.
Progressive epithelial to mesenchymal transitions in ARCaPE prostate cancer cells during xenograft tumor formation and metastasis
Authors: He Hui , Yang Xiaojian , Davidson Alec J. , Wu Daqing , Marshall Fray F. , Chung Leland W.K. , Zhau Haiyen E. , Wang Ruoxiang
Published: November 2009

BACKGROUND

The mechanism of epithelial to mesenchymal transition (EMT) could be adopted by tumor cells for migration and invasion. We have reported that ARCaPE human prostate cancer cells undergo EMT‐like changes during xenograft growth in athymic mice.

METHODS

In this report, we assessed the extent of EMT by tracking changes in cloned ARCaPE cells expressing red fluorescence protein during successive orthotopic prostate tumor formation. Cancer cells with stromal‐like morphology were isolated and examined for EMT‐like changes.

RESULTS

EMT‐like morphologic and expression changes were detected after one round of in vivo tumor formation. Importantly, when recovered tumor cells were used in second round xenograft tumor formation, a large fraction of ARCaPE cells showed drastic EMT‐like changes, with markedly enlarged cell size and divergent cell shapes similar to those of mesenchymal stromal cells. The morphologic change was accompanied by increased growth and metastasis, as tumor incidence increased while red fluorescent tumor cells could be detected from circulating blood, bone marrow, peritoneal ascites, and lung of the tumor‐bearing mice. Recovered clones from these samples had lost epithelial markers but many showed activated stromal marker vimentin expression. The EMT appeared permanent since the newly acquired morphology was sustained after continuous passages.

CONCLUSIONS

Results from this study demonstrate that through interaction with the host tumor microenvironment, cancer cells acquire cellular plasticity. During xenograft tumor formation and metastasis, a single clone of cancer cells could yield a heterogeneous population, with a substantial number of tumor cells adopting mesenchymal stroma‐like phenotypes. Prostate 70: 518–528, 2010. © 2009 Wiley‐Liss, Inc.
Ustekinumab: new option for moderate‐to‐severe psoriasis
Authors: Chaplin Steve , Downs Tony
Published: November 2009

Ustekinumab (Stelara), a novel biologic for the treatment of moderate‐to‐severe plaque psoriasis, targets interleukins rather than TNF‐alpha. In our New products review, Steve Chaplin presents the clinical data relating to its efficacy and adverse effects and Dr Downs discusses its place in psoriasis treatment. Copyright © 2009 Wiley Interface Ltd
Hypertension: GP guide to recommended treatment
Authors: McInnes Gordon , Vann Jones John
Published: November 2009

Our Drug review of hypertension discusses the properties of the wide range of antihypertensive agents available and their recommended use, both alone and in combination, followed by sources of further information in Resources. Copyright © 2009 Wiley Interface Ltd
Graphene quantum dots in perpendicular magnetic fields
Authors: Güttinger J. , Stampfer C. , Frey T. , Ihn T. , Ensslin K.
Published: November 2009

We report transport experiments on graphene quantum dots (QDs). We focus on excited state spectra in the near vicinity of the charge neutrality point and signatures of the electron–hole crossover as a function of a perpendicular magnetic field. Coulomb blockade resonances of a 50 nm wide and 80 nm long dot are visible at all gate voltages across the transport gap ranging from hole to electron transport. The magnetic field dependence of more than 40 states as a function of the back gate voltage can be interpreted in terms of the unique evolution of the diamagnetic spectrum of a graphene dot including the formation of the E = 0 Landau level, situated in the centre of the transport gap, and marking the electron–hole crossover. Around the crossover, excited states and cotunneling features are studied for varying perpendicular magnetic field.

magnified image

Schematic illustration of an etched graphene quantum dot with rough edges. The devices studied are still significantly larger than the presented one.
Multi‐component catalysts for the synthesis of SWCNT
Authors: Roch Aljoscha , Märcz Matthias , Richter Uwe , Leson Andreas , Beyer Eckhard , Jost Oliver
Published: November 2009

We developed a large‐scale synthesis of single‐walled carbon nanotubes (SWCNT) based entirely on the electric arc evaporation method. To get the desired result, an enhanced understanding and control of the evaporation process is of crucial importance. For best results, one has to control the temperature gradient of the evaporation zone for a high evaporation density (challenging task) or alternatively one has to develop catalysts suitable for catalytic operation over a large temperature range. We found multi‐component catalyst systems that allow both a low‐temperature SWCNT growth (200 °C) as well as a high‐temperature growth (1000 °C) and a lower SWCNT defect density. Multi‐component catalysts, therefore, offered the best results for both the laser evaporation process with the arc process with a similar SWCNT yield. The evaporation rate, however, is much higher for the arc technique. This favours the arc technique over the laser technique for an upscaled SWCNT synthesis process.
Guidance and nonlinear control system for autonomous flight of minirotorcraft unmanned aerial vehicles
Authors: Kendoul Farid , Yu Zhenyu , Nonami Kenzo
Published: November 2009

Small unmanned aerial vehicles (UAVs) are becoming popular among researchers and vital platforms for several autonomous mission systems. In this paper, we present the design and development of a miniature autonomous rotorcraft weighing less than 700 g and capable of waypoint navigation, trajectory tracking, visual navigation, precise hovering, and automatic takeoff and landing. In an effort to make advanced autonomous behaviors available to mini‐ and microrotorcraft, an embedded and inexpensive autopilot was developed. To compensate for the weaknesses of the low‐cost equipment, we put our efforts into designing a reliable model‐based nonlinear controller that uses an inner‐loop outer‐loop control scheme. The developed flight controller considers the system's nonlinearities, guarantees the stability of the closed‐loop system, and results in a practical controller that is easy to implement and to tune. In addition to controller design and stability analysis, the paper provides information about the overall control architecture and the UAV system integration, including guidance laws, navigation algorithms, control system implementation, and autopilot hardware. The guidance, navigation, and control (GN&C) algorithms were implemented on a miniature quadrotor UAV that has undergone an extensive program of flight tests, resulting in various flight behaviors under autonomous control from takeoff to landing. Experimental results that demonstrate the operation of the GN&C algorithms and the capabilities of our autonomous micro air vehicle are presented. © 2009 Wiley Periodicals, Inc.
Fault localization using a model checker
Authors: Griesmayer Andreas , Staber Stefan , Bloem Roderick
Published: November 2009

If a program does not fulfill its specification, a model checker can deliver a counterexample. However, although such a counterexample shows how the specification can be violated, it typically comprises large parts of the program and gives little information about which of the visited statements is responsible for the error. In this article, we show that model checkers can also be used to perform model‐based diagnosis and thus fault localization. The approach leads to significantly more precise diagnoses than the state‐of‐the‐art and typically rules out 90–99% of the code as possible fault locations. The approach is general and can be applied to any system that is amenable to model checking (with respect to language and complexity). To demonstrate the applicability and high precision of our approach, we present implementations for C programs using two different model checking tools and show experimental results from the TCAS case study and an integration with the DDVerify framework to debug Linux device drivers. Copyright © 2009 John Wiley & Sons, Ltd.
Simplified dynamic analysis of eccentric buildings with a setback. 2: the effect of stiffness irregularity
Authors: Georgoussis George K.
Published: November 2009

The effect of stiffness irregularity is investigated in eccentric buildings with a setback. Stiffness irregularity is assumed to be created when some of the lateral load resisting bents are curtailed at the top of the base structure. The methodology suggested in the companion paper for assessing vibration frequencies, base shears and torques is extended to include the effect of curtailed bents. Their contribution is evaluated by an indirect method after the modal stiffness of the symmetrical counterpart structure is determined and the modal contribution of the full height bents is assessed by Southwell's approach. A number of numerical examples, representing common types of building structures, are presented to illustrate the procedure and provide an insight into the response of such setback buildings. The results are compared with more accurate results obtained by three‐dimensional dynamic analyses. Copyright © 2009 John Wiley & Sons, Ltd.
Relative safety of high‐rise and low‐rise steel moment‐resisting frames in Los Angeles
Authors: Jones Pierson , Zareian Farzin
Published: November 2009

This study assesses the deformation demands posed by high hazard seismic events to some common steel moment frame (SMF) structures in the Los Angeles region. The structures under consideration were SMF structures designed using the 1994 UBC for high seismic risk, both short and tall, similar to many SMF structures in Los Angeles. Lumped plasticity frame models are developed with the most current knowledge of nonlinear modelling techniques and component properties and are subjected to recorded and simulated ground motions. The recorded ground motions are selected and scaled to represent a high hazard seismic event. The simulated ground motions are extracted from a simulation of a magnitude 7·15 rupture of the Puente Hills fault. The frame models are varied to consider brittle pre‐Northridge welds, ductile post‐Northridge welds as well as simplified and detailed modelling techniques. Structural safety is assessed in terms of the number of structures that exceeded a safe inter‐storey drift ratio for each ground motion set. Also, the relative safety of the tall and short SMF, taking into account brittle and ductile welds, is evaluated. Lastly, the differences in demands imposed by the recorded and scaled ground motions on tall SMF structures are compared. Copyright © 2009 John Wiley & Sons, Ltd.
Cerebrospinal fluid leakage and pneumocephalus secondary to spine stab wounds
Authors: Rahamimov Nimrod , Mulla Hani , Freiman Shay
Published: November 2009

Cerebro-spinal fluid leakage from a spinal stab wound is rare, and usually not a life-threatening injury. Pneumocephalus, a possible rare complication of traumatic cerebro-spinal fluid leakage, can potentially lead to intracranial hemorrhage and death. We describe two cases of spinal stab wounds complicated by cerebro-spinal fluid leakage, one of them developing into severe pneumocephalus. Both patients recovered completely with the following treatment protocol: (a) trendelenburg positioning of the patient, (b) insertion of a continuous-drainage cerebro-spinal fluid catheter into the lumbar thecal sac, (c) primary suture of the leaking skin wound, (d) IV antibiotic therapy.
Platinum Assisted Vapor–Liquid–Solid Growth of Er–Si Nanowires and Their Optical Properties
Authors: Kim Myoung-Ha , Kim Il-Soo , Park Yong-Hee , Park Tae-Eon , Shin Jung H. , Choi Heon-Jin
Published: November 2009

We report the optical activation of erbium coated silicon nanowires (Er–SiNWs) grown with the assist of platinum (Pt) and gold (Au), respectively. The NWs were grown on Si substrates by using a chemical vapor transport process using SiCl4 and ErCl4 as precursors. Pt as well as Au worked successfully as vapor–liquid–solid (VLS) catalysts for growing SiNWs with diameters of ~100 nm and length of several micrometers, respectively. The SiNWs have core–shell structures where the Er-crystalline layer is sandwiched between silica layers. Photoluminescence spectra analyses showed the optical activity of SiNWs from both Pt and Au. A stronger Er3+ luminescence of 1,534 nm was observed from the SiNWs with Pt at room- and low-temperature (25 K) using the 488- and/or 477-nm line of an Ar laser that may be due to the uniform incorporation of more Er ions into NWs with the exclusion of the formation of catalyst-induced deep levels in the band-gap. Pt would be used as a VLS catalyst for high performance optically active Er–SiNWs.
Physicochemical Characteristics and Composition of Indian Soybean Oil Deodorizer Distillate and the Recovery of Phytosterols
Authors: Khatoon Sakina , Raja Rajan R. G. , Gopala Krishna A. G.
Published: November 2009

The deodoriser distillate (DOD) of Indian soybean oil obtained from two industries processing soybean oil was investigated for its physicochemical characteristics, its composition of tocopherols, phytosterols, fatty acids and recovery of phytosterols for use in nutraceutical products. It was found that the two DOD samples studied were dark in color and had higher amounts of free fatty acids (22.7 and 49.9%), unsaponifiable matter (11.8 and 21.9%) (5–10 times found in soybean oil), total tocopherols (1957–2256 mg/100 g) (20 times the amount in soybean oil), and 6–10% of phytosterols (12–20 times the soybean oil). The fatty acids found were palmitic (23.2–25.5%), stearic (1.4–2.4%), oleic (23.8–26.1%), linoleic (40.4–41.1%) and linolenic (2.7–3.2%) acids. The unsaponifiable matter (21.9%) and phytosterols (8.7%) content of DOD‐2 were higher than in DOD‐1 and hence was more suited for isolation of phytosterols. Using hexane and water for crystallisation, the DOD‐2 yielded a phytosterol fraction with lower recovery of 13.2–17.8% while treatment with alkali to remove FFA and the glycerides followed by organic solvent extraction yielded unsaponifiable matter containing phytosterols with a recovery of 74.6%. Later the unsaponifiable matter was purified by double crystallisation into a mixture of phytosterols of 87% purity containing β‐sitosterol (34.3%), stigmasterol (3.1%) and campesterol (50.1%). The product may find use in foods, pharmaceuticals, cosmetics and allied industries probably as a nutraceutical.
The European Union's manifest destiny
Authors: Hökmark Gunnar
Published: November 2009

Two decades after the fall of the Berlin Wall it is time for reflection, but it is also a time for us in the established nations of the European Union to express gratitude. We might not always appreciate the free nations of Central and Eastern Europe, but we owe them a great deal. Their success is shaping our future.
SMEs in Europe: Taking Stock and Looking Forward
Authors: Erixon Fredrik
Published: November 2009

SMEs are often praised by politicians and economists alike as the backbone of the economy and an essential factor for employment. They represent the vast majority of the enterprises in Europe and the largest source of employment. Differently from large enterprises, small and medium enterprises enjoyed better image vis-à-vis the great public, and overtime managed to ensure governmental support in times of crisis. This article analyses both the role of SMEs for economic growth and employment and the extent to which they were affected by the financial crisis.
In Search of a Structure: The EU's Foreign Policy Strategy against the Background of a Missing Global Order
Authors: Algieri Franco , Kammel Arnold
Published: November 2009

Algieri and Kammel describe the evolution of the global power structure after the end of the Cold War equilibrium between the United States and the Soviet Union. The 1990s represented a period of intense global change marked by two realities: the dominant role of the US and the difficulty of defining a multipolar balance. The establishment of a multipolar equilibrium will necessarily include Asia's growing forces—India and China—and Russia, whereas the role of the EU remains uncertain.
Russia at the Gates: The Ambivalent Neighbour
Authors: Kalniete Sandra
Published: November 2009

A new tension in the relationship between Russia and its western neighbours, particularly Latvia, has emerged since countries in the former Russian sphere of influence were brought into the EU and NATO. The EU should make use of the new Member States' knowledge of Russia acquired during their forced coexistence, in order to promote the emergence of effective cooperation with Moscow. The author argues that a rapid reduction of Russia's labour force, corresponding to its demographic decline, will advance Russia's political ambitions to return to the politics of power that existed in the nineteenth century. Russia will not stop trying to interfere in regional politics and will find new tools, such as energy, to do so. Russia's inability to offer an honest evaluation of history, along with its resurgence as an authoritarian state and as a military and energy superpower, does not reveal Russia as a friend of a united Europe.
After the Wall: Competing Narratives of Germany's Unification 20 Years after the Wende
Authors: Freudenstein Roland
Published: November 2009

Germany's peaceful unification 20 years ago can be rated as one of the lasting success stories of German and European history. Nevertheless, some feelings of frustration with unification and the ensuing process of transition in the East continue to exist among many East and West Germans. While West Germans often feel like the paymasters of German unity, many East Germans feel their lifetime in the GDR is not respected and argue that even Communist East Germany would have had a few positive contributions to make to a united Germany. While these frustrations are slowly receding in their significance for day-to-day public affairs, the centre of gravity of German politics has shifted leftward domestically and especially in foreign policy.
Interprofessional team approach to infertility treatment in Japan
Authors: Yano Keiko , Ohashi Kazutomo
Published: November 2009

Purpose

At present, a team approach involving gynecologists, nurses, embryologists, and the other professionals is considered necessary to provide successful infertility treatment. First, we documented which professionals were in charge during various phases of infertility treatment. Second, clinical staff and patients were surveyed regarding their expectations regarding which of these professionals should contribute during examination, during treatment and after treatment for infertility.

Methods

We surveyed the actual situation perceived by staff as well as the desired situation for staff and patients in relation to 21 procedures related to infertility treatment. We distributed 781 questionnaires to staff and patients at 86 facilities. Of 380 returned by mail, we analyzed 128 responses from staff who worked with four types of professionals or specialists, i.e., medical doctors, nurses, embryologists, and medical clerks, and 46 from patients who consulted these professionals during their treatment.

Results

Most staff recognized 5 of 15 procedures before and after treatment as being conducted by medical doctors alone. However, explanation and consultation regarding the methods and schedule were mainly performed with an interprofessional team approach. Expectations regarding professionals in charge differed between staff and patients. A team approach including infertility counselors and medical clerks was utilized and considered desirable during counseling.

Conclusions

An effective team approach should be established for each step of infertility treatment.
Best friend attachment versus peer attachment in the prediction of adolescent psychological adjustment
Authors: Wilkinson Ross B.
Published: November 2009

This study examined the utility of the newly developed Adolescent Friendship Attachment Scale (AFAS) for the prediction of adolescent psychological health and school attitude. High school students (266 males, 229 females) were recruited from private and public schools in the Australian Capital Territory with ages of participants ranging from 13 to 19 years. Self‐report measures of depression, self‐esteem, self‐competence and school attitude were administered in addition to the AFAS and a short‐form of the Inventory of Parental and Peer Attachment (IPPA). Regression analyses revealed that the AFAS Anxious and Avoidant scales added to the prediction of depression, self‐esteem, self‐competence, and school attitude beyond the contribution of the IPPA. It is concluded that the AFAS taps aspects of adolescent attachment relationships not assessed by the IPPA and provides a useful contribution to research and practice in the area of adolescent psycho‐social adjustment.
Cardioprotective activity of a novel and potent competitive inhibitor of lactate dehydrogenase
Authors: Kotlyar Alexander B. , Randazzo Antonio , Honbo Norman , Jin Zhu-Qui , Karliner Joel S. , Cecchini Gary
Published: November 2009

Alkaline incubation of NADH results in the formation of a very potent inhibitor of lactate dehydrogenase. High resolution mass spectroscopy along with NMR characterization clearly showed that the inhibitor is derived from attachment of a glycolic acid moiety to the 4‐position of the dihydronicotinamide ring of NADH. The very potent inhibitor is competitive with respect to NADH. The inhibitor added in submicromolar concentrations to cardiomyocytes protects them from damage caused by hypoxia/reoxygenation stress. In isolated mouse hearts, addition of the inhibitor results in a substantial reduction of myocardial infarct size caused by global ischemia/reperfusion injury.
Invariance de laK-Théorie par équivalences dérivées
Authors: Cisinski Denis-Charles
Published: November 2009

Ces notes ont pour but de démontrer que tout foncteur exact à droite entre catégories de Waldhausen raisonnables, induisant une équivalence au niveau des catégories homotopiques, définit une équivalence d'homotopie entre les spectres deK-théorie correspondants. Cela généralise un résultat bien connu de Thomason et Trobaugh. Les ingrédients de démonstration sont une généralisation du théorème d'approximation de Waldhausen et une caractérisation combinatoire simple des équivalences dérivées. On étudie par ailleurs la localisation simpliciale des catégories de Waldhausen. On démontre qu'un foncteur (homotopiquement) exact à droite induit une équivalence de catégories homotopiques si et seulement s'il induit une équivalence au niveau des localisations simpliciales. Cela permet de faire le lien avec laK-théorie des catégories simpliciales introduite par Toën et Vezzosi.
Hermitian K-theory of exact categories
Authors: Schlichting Marco
Published: November 2009

We study the theory of higher Grothendieck-Witt groups, alias algebraic hermitian K-theory, of symmetric bilinear forms in exact categories, and prove additivity, cofinality, dévissage and localization theorems – preparing the ground for the theory of higher Grothendieck-Witt groups of schemes as developed in [Sch08a] and [Sch08b]. No assumption on the characteristic is being made.
The Euler characteristic and Euler defect for comodules over Euler coalgebras
Authors: Simson Daniel
Published: November 2009

Let K be a field. We study a class of left C-comodules over a basic left Euler coalgebra C by means of the Euler ℤ-bilinear form associated to C, the Euler characteristic χC(M,N) of left C-comodules M,N, and the defect ∂C(M,N) ∊ ℤ associated to any computable Euler pair (M,N) of left C-comodules. We show that (lgthM, lgthN) = χC(M,N) + ∂C(M,N), for any computable Euler pair (M,N) of comodules over a left Euler coalgebra C. One of the main results of the paper asserts that the defect ∂C(M,N) is zero and (lgthM,lgthN) = χC(M,N), if the comodules M,N are finite-dimensional.
Stratigraphic record of Neoproterozoic ice sheet collapse: the Kapp Lyell diamictite sequence, SW Spitsbergen, Svalbard
Authors: BJØRNERUD M. G.
Published: November 2009

The diamictites of the Neoproterozoic Kapp Lyell Sequence in northern Wedel Jarlsberg Land, southwest Spitsbergen, have long been recognized as ancient glacial deposits, but their place within the global stratigraphic framework of ‘snowball Earth’ has remained unclear, owing to the complexity of superimposed Caledonian deformation and to the relatively inaccessible terrain in which they occur. Recently deglaciated exposures of the rocks now provide a more complete picture of the changing environment in which the diamictites were deposited, and new understanding of regional correlations help constrain their place in the global chronostratigraphy of the Cryogenian Period. The 2500 m thick Kapp Lyell Sequence consists of three distinct types of glaciomarine diamictite. The succession begins with about 1000 m of finely laminated diamictite containing abundant lonestones. The millimetre- to centimetre-scale laminae, apparent suspension deposits, consist of sand- to silt-sized particles of quartz and dolomite alternating with thin films of graphitic phyllite. The laminated unit gives way abruptly to 500–1000 m of unsorted, unlayered diamictite that alternates and interfingers with graded beds of conglomerate to sandstone. These apparent turbidite deposits become increasingly prevalent toward the top of the exposed section. Regional lithostratigraphic relationships suggest that the Kapp Lyell sequence corresponds to the second major stage of Neoproterozoic glaciation at c. 635 Ma. The graphitic material in the laminated unit yields δ13C values in the range of −20 to −22 ‰, pointing to a biogenic origin and an active marine biosphere at the time of deposition. The preservation of organic carbon and unusually large ratios of highly reactive Fe to total Fe suggest that low oxygen conditions prevailed in the deep basin that received these sediments. The transition from laminated, to unsorted, to graded diamictites may represent change from (1) a stable ice margin that released rare icebergs into a deep, quiet basin to (2) a collapsing ice sheet that unleashed flotillas of icebergs and large volumes of sediment to (3) submarine landslides that triggered turbidity flows from the rapidly deposited, gravitationally unstable sediments. The Kapp Lyell diamictite sequence appears to chronicle the demise of a large ice mass in this part of the Neoproterozoic world.
Ion steric effects on electrophoresis of a colloidal particle
Authors: KHAIR ADITYA S. , SQUIRES TODD M.
Published: November 2009

We calculate the electrophoretic mobility Me of a spherical colloidal particle, using modified Poisson–Nernst–Planck (PNP) equations that account for steric repulsion between finite sized ions, through Bikerman's mean-field model (Bikerman, Phil. Mag., vol. 33, 1942, p. 384). Ion steric effects are controlled by the bulk volume fraction of ions ν, and for ν = 0 the standard PNP equations are recovered. An asymptotic analysis in the thin-double-layer limit reveals at small zeta potentials (ζ < kBT/e ≈ 25 mV) Me to increase linearly with ζ for all ν, as expected from the Helmholtz–Smoluchowski (HS) formula. For larger ζ, however, it is well known that surface conduction of ions within the double layer reduces Me below the HS result. Crucially, however, in the PNP equations surface conduction becomes significant precisely because of the aphysically large and unbounded counter-ion densities predicted at large ζ. In contrast, ion steric effects impose a limit on the counter-ion density, thereby mitigating surface conduction. Hence, Me does not fall as far below HS for finite sized ions (ν ≠ 0). Indeed, at sufficiently large ν, ion steric effects are so dramatic that a maximum in Me is not observed for physically reasonable values of ζ(≤ 10 kBT/e), in stark contrast to the PNP-based calculations of O'Brien & White (J. Chem. Soc. Faraday Trans. II, vol. 74, 1978, p. 1607) and O'Brien (J. Colloid Interface Sci., vol. 92, 1983, p. 204). Finally, by calculating a Dukhin–Bikerman number characterizing the relative importance of surface conduction, we collapse Me versus ζ data for different ν onto a single master curve.
Vortex-induced vibration of a prism in internal flow
Authors: SÁNCHEZ-SANZ M. , VELAZQUEZ A.
Published: November 2009

In this article, we study the influence of solid-to-fluid density ratio m on the type of vortex-induced oscillation of a square section prism placed inside a two-dimensional channel. We assume that the solid body has neither structural damping nor spring restoring force. Accordingly, the prism equation of motion contains only inertia and aerodynamics forces. The problem is considered in the range of Reynolds numbers Re ∈ [50 200] (based on the prism cross-section height h) and channel widths H = H′/h ∈ [2.5 10]. We found that, for each Re and H, there is a critical mass ratio mc that separates two different oscillation regimes. For m > mc, the prism oscillation is periodical and contains a single harmonic. For m < mc, the prism oscillation changes completely and assumes an irregular pattern that is characterized by multiple harmonics that appear to belong to a uniform spectrum. The change from one regime to the other is abrupt and we were not able to observe a transitional regime in which the number of response harmonics grew by finite steps. The value of the critical mass ratio grows along with the Reynolds number and the channel width.
A DNS study of effects of particle–particle collisions and two-way coupling on particle deposition and phasic fluctuations
Authors: NASR HOJJAT , AHMADI GOODARZ , MCLAUGHLIN JOHN B.
Published: November 2009

This study is concerned with the effects of particle–particle collisions and the two-way coupling on the dispersed and carrier phase turbulence fluctuations in a channel flow. The time history of the instantaneous turbulent velocity vector was generated by the two-way coupled direct numerical simulation of the Navier–Stokes equations via a pseudo-spectral method. The particle equation of motion included the wall-corrected nonlinear drag force and the wall-induced and shear-induced lift force. The effect of particles on the flow was included in the analysis via a feedback force that acted on the computational grid points. Several simulations for different particle relaxation times and particle mass loadings were performed, and the effects of particle–particle collisions, particle feedback force and inter-particle interactions on the particle deposition velocity, fluid and particle fluctuating velocities, and particle concentration profiles were determined. The effect of particle aerodynamic interactions was also examined for certain cases.

The simulation results indicated that when particle–particle collisions were included in the computation but two-way coupling effects were ignored, the particle normal fluctuating velocity increased in the wall region causing an increase in the particle deposition velocity. When the particle collisions were neglected but the particle–fluid two-way coupling effects were accounted for, the two-way coupling and the particle normal fluctuating velocity decreased near the wall causing a decrease in the particle deposition velocity. In the case of the four-way coupling in which both inter-particle collisions and two-way coupling effects were present, it was found that the particle deposition velocity increased compared with the one-way coupling case. When the particle aerodynamic interactions were added to the four-way coupled case (termed six-way coupled case), no significant changes in the mean fluid and particle velocities and the fluid and particle fluctuating velocities were obtained.

The results for the particle concentration profile indicated that the inclusion of two-way coupling or inter-particle collisions into the computation reduced the accumulation of particles near the wall. It was also observed that particle–particle collisions and two-way coupling weakened the preferential distribution of particles.
The Number of Independent Sets in a Regular Graph
Authors: ZHAO YUFEI
Published: November 2009

We show that the number of independent sets in an N-vertex, d-regular graph is at most (2d+1 − 1)N/2d, where the bound is sharp for a disjoint union of complete d-regular bipartite graphs. This settles a conjecture of Alon in 1991 and Kahn in 2001. Kahn proved the bound when the graph is assumed to be bipartite. We give a short proof that reduces the general case to the bipartite case. Our method also works for a weighted generalization, i.e., an upper bound for the independence polynomial of a regular graph.
RHO PROTEINS, PREGNANCY AND LABOUR
Authors: LARTEY J , LÓPEZ BERNAL A
Published: November 2009

Premature birth is the most important cause of perinatal death and long term morbidity in the world today. Although an increasing proportion of premature births are induced secondary to pre-existing fetal and maternal conditions, over half of these deliveries are due to spontaneous onset of uterine contractions (spontaneous preterm labour). So far, our ability to successfully treat women whose pregnancies are complicated by preterm labour is hampered by a lack of knowledge of the endocrine and biochemical factors that initiate human parturition.
On the complexity of identifying head-elementary-set-free programs
Authors: FASSETTI FABIO , PALOPOLI LUIGI
Published: November 2009

Head-elementary-set-free (HEF) programs were proposed in (Gebser et al. 2007) and shown to generalize over head-cycle-free programs while retaining their nice properties. It was left as an open problem in (Gebser et al. 2007) to establish the complexity of identifying HEF programs. This note solves the open problem by showing that the problem is complete for coNP.
Surf zone diffusivity on a rip‐channeled beach
Authors: Brown Jeff , MacMahan Jamie , Reniers Ad , Thornton Ed
Published: November 2009

Absolute and relative diffusivity are measured on a rip‐channeled beach using 30 position‐tracking drifters released in clusters (4–12 drifters) deployed on 7 days with different wave forcing and tidal elevations at Sand City, Monterey Bay, California. Diffusivity and dispersion were found to be larger on days with rip current flow patterns and larger waves. Rip currents cause material to diffuse quickly for t < 90 s in the cross shore (κxx = 5.4–6.1 m2/s) before decreasing to an asymptotic oscillation (κxx = 0.9–2.2 m2/s), while alongshore material diffusion is initially (t < 170 s) smaller than cross‐shore diffusion and asymptotes at a larger value (κyy = 2.8–3.8 m2/s). The cross‐ and alongshore absolute diffusivity modulate at ∼300 s corresponding to the average circulation time for a rip current. Two‐particle relative dispersion (Dp) grows like Dp2 ∼ t4/3 and the relative diffusivity (Kp) is scale dependent, Kp ∼ d0.2 (d is particle separation). Cluster relative diffusion (Ke) ranged from 1.0 to 4.5 m2/s and cluster relative dispersions (De) are significantly correlated with two‐particle relative dispersions (DS) [R2 > 0.9]. Two independent methods are used to measure the small‐scale turbulent diffusion contribution (kxy), which are found significantly correlated (R2 = 0.95) with each other and calculated surf zone wave breaking induced turbulent eddy viscosity. Here kxy is small relative to the total dispersion (Ke/kxy = 3–30), indicating that the shear flow is the primary mechanism responsible for dispersion in a rip current system.
Adjacent releases of mantle helium and soil CO2 from active faults: Observations from the Marmara region of the North Anatolian Fault zone, Turkey
Authors: Doğan Turhan , Sumino Hirochika , Nagao Keisuke , Notsu Kenji , Tuncer M. Kemal , Çelik Cengiz
Published: November 2009

Volatile releases, in terms of CO2 efflux and noble gas of mantle origin, are investigated in the Marmara region of the seismically active North Anatolian Fault (NAF) zone. A total of 180 CO2 efflux measurements (1 to 309 g m−2d−1) were carried out along four transects across the NAF. Spatial variability of surface CO2 effluxes was higher at faulted sites, relative to comparable background areas. The δ13C values of soil CO2 are −24.0 to −15.6‰ without correlation with CO2 efflux values, which suggest that CO2 efflux anomaly is caused by fault‐related biogenic gas flow. Furthermore, 36 gas and water samples from spring sites were investigated for 3He/4He ratios which resulted in a range from 0.26 R/RA to 4.22 R/RA. Large mantle helium contributions were observed from several sources along the NAF. The high CO2 efflux sector on the Gaziköy‐Saros fault along the NAF coincides with the area of high mantle helium flux. This shows that fault zones play an important role both in transferring mantle helium to the surface and in causing fault‐related biogenic gas flow.
Pattern and velocity of propagation of the global ocean eddy variability
Authors: Fu Lee‐Lueng
Published: November 2009

Satellite altimeter data are used to study the characteristics of the horizontal propagation of eddy variability of the global oceans. Decade‐long time series of sea surface height is analyzed for finding the maximum cross correlation with neighboring time series within a window of space and time lags. The space and time lags corresponding to the maximum correlation allow an estimate of the propagation velocity of the eddy variability that dominates the variance of sea surface height anomalies. The method cannot distinguish the various forms of eddy variability: isolated eddies and fronts, the meandering of ocean currents, or planetary waves. However, the results provide, at a given location of the global oceans, a uniquely determined propagation velocity that represents a time‐averaged description of the tendency of the movement of the local eddy variability. The propagation velocity is highly inhomogeneous in space. Outside the equatorial zone, the zonal propagation is intrinsically westward, modified by ocean currents, which could reverse the zonal propagation to eastward in regions like the Gulf Stream and the Antarctic Circumpolar Current. At midlatitudes and high latitudes, the propagation pattern is highly affected by the path of ocean currents and the shape of bottom topography. At tropical latitudes, the meridional propagation is convergent toward the equator in the western basins and divergent away from the equator in the eastern basins. Comparison with the simulations of an eddy‐permitting ocean general circulation model shows overall agreement, especially in the latitudinal variation of the zonal propagation velocity. The result suggests that the model has captured the essence of the dynamics governing the propagation of ocean eddy variability.
Obtaining New Insights for Biodiversity Conservation from Broad-Scale Citizen Science Data
Authors: Kelling Steve , Fink Daniel , Hochachka Wesley , Iliff Marshall , Sullivan Brian , Wood Christopher , Munson Arthur , Riedewald Mirek
Published: November 2009

Increasing public engagement in volunteer science1, either through data collection2 or processing3, is both raising public awareness of science and gathering useful information for scientists. While the payoffs of citizen science4 are potentially large, achieving them requires new approaches to data management and analysis that can only result from strong cross-disciplinary collaborations. This is especially true in ecology and conservation biology, where historically the understanding of species’ responses to environmental change has been constrained by the limited spatial5 or temporal scale6 of available data. Here we describe collaborative research in ecology, computer science, and statistics to generate essential information for conservation management of North American birds: accurate dynamic bird distributions models based on habitat associations across much of North America. Unique is our ability to describe the broad-scale dynamics of seasonal bird distributions and the associated seasonal patterns of habitat use. Our source of bird distribution data is eBird7, an online bird checklist program that currently gathers more than 74,000 checklists monthly from a large network of contributors. Our results were made possible through a data intensive scientific workflow8 that includes analytical methods merged from the fields of machine learning and statistics. We believe that this novel approach of data collection, synthesis, analysis, and visualization will serve as a hallmark for future research initiatives, with broad applicability across many scientific domains.
Increased flood frequency and magnitude decreases density of a stream-breeding salamander in urbanized watersheds
Authors: Barrett Kyle , Guyer Craig
Published: November 2009

Background/Question/Methods

As urbanization increases across the globe, more ecologists have taken note of its consequences to stream systems. Sufficient data have been collected to document repeated patterns in urbanized streams for many abiotic parameters, aquatic insects, and fish. For example, we now know that urbanized streams experience more frequent and intense spates as a result of increased runoff form impervious surfaces in the urban watershed. The spates eventually lead to a more incised and wider stream bed. Such abiotic shifts consistently result in decreased aquatic invertebrate and fish diversity. More recently, stream-breeding salamanders have been observed to decrease in density in urban areas. We monitored the density of southern two-lined salamanders for the duration of two cohorts in 12 streams in western Georgia, USA. We then used path analysis to determine the relationships between land-use change, abiotic shifts in the stream environment, and larval salamander density.

Results/Conclusions

We found that southern two-lined salamanders in the streams we monitored exhibited no change in reproductive output between urban and reference habitats. However, repeated sampling throughout the larval period revealed a large decline in density of larvae in urban areas prior to metamorphosis, while a similar decline was not seen in reference habitats. We evaluated several hypotheses that might explain the observed decline in urban areas, and a model in which increased impervious surface causes an increase in spate frequency and magnitude, which then leads to decreased larval density had the most support. This is the first attempt to compare multiple plausible hypotheses as to why salamander density and diversity decreases in urban habitats. By describing larval density at the beginning and end of the larval period, and by identifying a likely mechanism for the observed decline in density, species-specific and stream restoration efforts can be enhanced.