bluuebunny/crossref_metadata_2025 huggingface dataset:
Substituent Dependent Dimensionality in Luminescent Zinc Isophthalate Coordination Polymers Containing Bis(3‐pyridylmethyl)piperazine
Authors: Pochodylo Amy L. , LaDuca Robert L.
Published: September 2010

Divalent zinc coordination polymers containing bis(3‐pyridylmethyl)piperazine (3‐bpmp) and isophthalate ligands have been hydrothermally synthesized and structurally characterized by single‐crystal X‐ray diffraction. {[Zn(ip)(H3‐bpmp)]ClO4·4H2O}n (1, ip = isophthalate) has twofold parallel interpenetrated (4,4) grid cationic coordination polymer nets, with unligated perchlorate ions and intriguing infinite water molecule chains. {[Zn2(NO2ip)3(H23‐bpmp)(H2O)5]·3H2O}n (2, NO2ip = 5‐nitroisophthalate) exhibits a supramolecular lattice built from 1D chain motifs, revealing a significant dependence of topology on the steric bulk of the dicarboxylate ligand. Luminescent properties for 1 and 2 are also reported.
The 3‐methylglutaconic acidurias: what's new?
Authors: Wortmann Saskia B. , Kluijtmans Leo A. , Engelke Udo F. H. , Wevers Ron A. , Morava Eva
Published: September 2010

The heterogeneous group of 3‐methylglutaconic aciduria (3‐MGA‐uria) syndromes includes several inborn errors of metabolism biochemically characterized by increased urinary excretion of 3‐methylglutaconic acid. Five distinct types have been recognized: 3‐methylglutaconic aciduria type I is an inborn error of leucine catabolism; the additional four types all affect mitochondrial function through different pathomechanisms. We provide an overview of the expanding clinical spectrum of the 3‐MGA‐uria types and provide the newest insights into the underlying pathomechanisms. A diagnostic approach to the patient with 3‐MGA‐uria is presented, and we search for the connection between urinary 3‐MGA excretion and mitochondrial dysfunction.
Tyrosine monitoring in children with early and continuously treated phenylketonuria: results of an international practice survey
Authors: Sharman Rachael , Sullivan Karen A. , Young Ross McD. , McGill James J.
Published: September 2010

Investigations into the biochemical markers associated with executive function (EF) impairment in children with early and continuously treated phenylketonuria (ECT‐PKU) remain largely phenylalanine‐only focused, despite experimental data showing that a high phenylalanine:tyrosine (phe:tyr) ratio is more strongly associated with EF deficit than phe alone. A high phe:tyr ratio is hypothesized to lead to a reduction in dopamine synthesis within the brain, which in turn results in the development of EF impairment. This paper provides a snapshot of current practice in the monitoring and/or treatment of tyrosine levels in children with PKU, across 12 countries from Australasia, North America and Europe. Tyrosine monitoring in this population has increased over the last 5 years, with over 80% of clinics surveyed reporting routine monitoring of tyrosine levels in infancy alongside phe levels. Twenty‐five percent of clinics surveyed reported actively treating/managing tyrosine levels (with supplemental tyrosine above that contained in PKU formulas) to ensure tyrosine levels remain within normal ranges. Anecdotally, supplemental tyrosine has been reported to ameliorate symptoms of both attention deficit hyperactivity disorder and depression in this population. EF assessment of children with ECT‐PKU was likewise highly variable, with 50% of clinics surveyed reporting routine assessments of intellectual function. However when function was assessed, test instruments chosen tended towards global measures of IQ prior to school entry, rather than specific assessment of EF development. Further investigation of the role of tyrosine and its relationship with phe and EF development is needed to establish whether routine tyrosine monitoring and increased supplementation is recommended.
Nanospiral Formation by Droplet Drying: One Molecule at a Time
Authors: Wan Lei , Li Li , Mao Guangzhao
Published: September 2010

We have created nanospirals by self-assembly during droplet evaporation. The nanospirals, 60–70 nm in diameter, formed when solvent mixtures of methanol and m-cresol were used. In contrast, spin coating using only methanol as the solvent produced epitaxial films of stripe nanopatterns and using only m-cresol disordered structure. Due to the disparity in vapor pressure between the two solvents, droplets of m-cresol solution remaining on the substrate serve as templates for the self-assembly of carboxylic acid molecules, which in turn allows the visualization of solution droplet evaporation one molecule at a time.
Enhanced Specificity of Multiplex Polymerase Chain Reaction via CdTe Quantum Dots
Authors: Liang Gaofeng , Ma Chao , Zhu Yanliang , Li Shuchun , Shao Youhua , Wang Yong , Xiao Zhongdang
Published: September 2010

Nanoparticles were recently reported to be able to improve both efficiency and specificity in polymerase chain reaction (PCR). Here, CdTe QDs were introduced into multi-PCR systems. It was found that an appropriate concentration of CdTe QDs could enhance the performance of multi-PCR by reducing the formation of nonspecific products in the complex system, but an excessive amount of CdTe QDs could suppress the PCR. The effects of QDs on PCR can be reversed by increasing the polymerase concentration or by adding bovine serum albumin (BSA). The mechanisms underlying these effects were also discussed. The results indicated that CdTe QDs could be used to optimize the amplification products of the PCR, especially in the multi-PCR system with different primers annealing temperatures, which is of great significance for molecular diagnosis.
Giant Persistent Photoconductivity of the WO3 Nanowires in Vacuum Condition
Authors: Huang Kai , Zhang Qing
Published: September 2010

A giant persistent photoconductivity (PPC) phenomenon has been observed in vacuum condition based on a single WO3 nanowire and presents some interesting results in the experiments. With the decay time lasting for 1 × 104 s, no obvious current change can be found in vacuum, and a decreasing current can be only observed in air condition. When the WO3 nanowires were coated with 200 nm SiO2 layer, the photoresponse almost disappeared. And the high bias and high electric field effect could not reduce the current in vacuum condition. These results show that the photoconductivity of WO3 nanowires is mainly related to the oxygen adsorption and desorption, and the semiconductor photoconductivity properties are very weak. The giant PPC effect in vacuum condition was caused by the absence of oxygen molecular. And the thermal effect combining with oxygen re-adsorption can reduce the intensity of PPC.
Atomic Force Microscopy Study of Protein–Protein Interactions in the Cytochrome CYP11A1 (P450scc)-Containing Steroid Hydroxylase System
Authors: Ivanov YD , Frantsuzov PA , Zöllner A , Medvedeva NV , Archakov AI , Reinle W , Bernhardt R
Published: September 2010

Atomic force microscopy (AFM) and photon correlation spectroscopy (PCS) were used for monitoring of the procedure for cytochrome CYP11A1 monomerization in solution without phospholipids. It was shown that the incubation of 100 μM CYP11A1 with 12% Emulgen 913 in 50 mM KP, pH 7.4, for 10 min at T = 22°C leads to dissociation of hemoprotein aggregates to monomers with the monomerization degree of (82 ± 4)%. Following the monomerization procedure, CYP11A1 remained functionally active. AFM was employed to detect and visualize the isolated proteins as well as complexes formed between the components of the cytochrome CYP11A1-dependent steroid hydroxylase system. Both Ad and AdR were present in solution as monomers. The typical heights of the monomeric AdR, Ad and CYP11A1 images were measured by AFM and were found to correspond to the sizes 1.6 ± 0.2 nm, 1.0 ± 0.2 nm and 1.8 ± 0.2 nm, respectively. The binary Ad/AdR and AdR/CYP11A1mon complexes with the heights 2.2 ± 0.2 nm and 2.8 ± 0.2 nm, respectively, were registered by use of AFM. The Ad/CYP11A1mon complex formation reaction was kinetically characterized based on optical biosensor data. In addition, the ternary AdR/Ad/CYP11A1 complexes with a typical height of 4 ± 1 nm were AFM registered.
Brief report: The impact of Attention Deficit Hyperactivity Disorder (ADHD) symptoms on academic performance in an adolescent community sample
Authors: Birchwood James , Daley Dave
Published: September 2010

Less is understood about the relationship between ADHD symptoms and academic performance in adolescents than the relationship in younger children. As such, the aim of the present study was to investigate the prospective relationship between ADHD symptoms and academic performance in a community adolescent sample. Three hundred and twenty‐four participants, aged 15 and 16, in their final year of compulsory education, completed measures of ADHD, anxiety, depression, and motivation, and a test of general cognitive ability. Participants were also asked for permission for their academic grades to be viewed on a later occasion (approximately 6 months later). In regression analyses, ADHD symptoms were the most significant independent psychopathological predictor of academic performance, and were almost as significant as motivation and cognitive ability. The results suggest that adolescents with more ADHD symptoms are likely to encounter greater academic difficulties.
Phosphoproteomics in cancer
Authors: Harsha H.C. , Pandey Akhilesh
Published: September 2010

Reversible protein phosphorylation serves as a basis for regulating a number of cellular processes. Aberrant activation of kinase signaling pathways is commonly associated with several cancers. Recent developments in phosphoprotein/phosphopeptide enrichment strategies and quantitative mass spectrometry have resulted in robust pipelines for high‐throughput characterization of phosphorylation in a global fashion. Today, it is possible to profile site‐specific phosphorylation events on thousands of proteins in a single experiment. The potential of this approach is already being realized to characterize signaling pathways that govern oncogenesis. In addition, chemical proteomic strategies have been used to unravel targets of kinase inhibitors, which are otherwise difficult to characterize. This review summarizes various approaches used for analysis of the phosphoproteome in general, and protein kinases in particular, highlighting key cancer phosphoproteomic studies.
Financialised Capitalism Soviet Style? Varieties of State Capture and Crisis
Authors: Visser Oane , Kalb Don
Published: September 2010

Looking for new ways to interpret the failings of the neo-liberal economy, this article argues that financialised capitalism at the eve of the 2008 financial crisis showed striking analogies with the characteristic combination of oligopoly and informality of the Soviet economy at the eve of its collapse. State capture by oligopolists, a large "virtual economy", the inability of agencies to obtain insight into economic and financial operations, the short term orientations of managers not coinciding with enterprise viability, and a "mystification of risk" by high science are some of the analogies to be discussed. It is argued that not only the origins but also the aftermath of the crisis may show significant analogies.
Producing Textbook Sociology
Authors: Manza Jeff , Sauder Michael , Wright Nathan
Published: September 2010

The conservative role of the textbook in reproducing the dominant ideas of a disciplinary field is well known. The factors driving that content have remained almost entirely unexamined. Reviewing the universe of textbooks aimed at the American market between 1998 and 2004, we explore the persistence of the identification in American sociology textbooks of a paradigm in which structural functionalism, conflict theory, and symbolic interactionism are used to frame the theoretical core of the discipline. We examine how over time the textbook market produces both supply and demand pressures to reproduce content that is at odds with the mainstream of the profession. We draw upon in-depth interviews with recent textbook authors and their editors.
High-oleic rapeseed (canola) and flaxseed oils modulate serum lipids and inflammatory biomarkers in hypercholesterolaemic subjects
Authors: Gillingham Leah G. , Gustafson Jennifer A. , Han Song-Yee , Jassal Davinder S. , Jones Peter J. H.
Published: September 2010

Recently, novel dietary oils with modified fatty acid profiles have been manufactured to improve fatty acid intakes and reduce CVD risk. Our objective was to evaluate the efficacy of novel high-oleic rapeseed (canola) oil (HOCO), alone or blended with flaxseed oil (FXCO), on circulating lipids and inflammatory biomarkersv.a typical Western diet (WD). Using a randomised, controlled, crossover trial, thirty-six hypercholesterolaemic subjects consumed three isoenergetic diets for 28 d each containing approximately 36 % energy from fat, of which 70 % was provided by HOCO, FXCO or WD. Dietary fat content of SFA, MUFA, PUFAn-6 andn-3 was 6, 23, 5, 1 % energy for HOCO; 6, 16, 5, 7·5 % energy for FXCO; 11·5, 16, 6, 0·5 % energy for WD. After 28 d, compared with WD, LDL-cholesterol was reduced 15·1 % (P < 0·001) with FXCO and 7·4 % (P < 0·001) with HOCO. Total cholesterol (TC) was reduced 11 % (P < 0·001) with FXCO and 3·5 % (P = 0·002) with HOCO compared with WD. Endpoint TC differed between FXCO and HOCO (P < 0·05). FXCO consumption reduced HDL-cholesterol by 8·5 % (P < 0·001) and LDL:HDL ratio by 7·5 % (P = 0·008)v.WD. FXCO significantly decreased E-selectin concentration compared with WD (P = 0·02). No differences were observed in inflammatory markers after the consumption of HOCO compared with WD. In conclusion, consumption of novel HOCO alone or when blended with flaxseed oil is cardioprotective through lipid-lowering effects. The incorporation of flaxseed oil may also target inflammation by reducing plasma E-selectin.
Efficacy of various dietary calcium salts to improve intestinal resistance toSalmonellainfection in rats
Authors: ten Bruggencate Sandra J. M. , Snel Johannes , Schoterman Margriet H. C. , Ertmann Ellen , van der Meulen Esther , Schonewille Arjan , Bovee-Oudenhoven Ingeborg M. J.
Published: September 2010

Previous animal and human studies have shown protective effects of Ca on the resistance to enteropathogenic infections. Most interventions were performed with calcium phosphate and little is known about the protective effect of other dietary sources of Ca. Therefore, we investigated the efficacy of several Ca salts to enhance intestinal resistance toSalmonella enteritidisinfection. Rats (n7–8 per group) were fed a high-fat, Western human-style, purified diet with a low Ca content (20 mmol calcium phosphate/kg; negative control group) or the same diet supplemented with either (extra) calcium phosphate, milk Ca, calcium chloride or calcium carbonate (total of 100 mmol Ca supplement/kg). Diets contained Cr-EDTA for assessment of incremental changes in intestinal permeability. After an adaptation period of 2 weeks, animals were orally infected withS. enteritidisto mimic a human-relevant foodborne infection. Ca supplement-induced changes on faecal lactobacilli and enterobacteria were studied before infection. Changes in intestinal permeability were determined by measuring urinary Cr with time. Persistence ofSalmonellawas determined by studying faecal excretion of this pathogen in time. Overall, all Ca salts increased resistance towardsSalmonella. After infection, body weight gain and food intake were higher in the calcium phosphate group. Calcium phosphate and milk Ca decreased faecal enterobacteria before infection. All Ca salts decreased infection-induced intestinal permeability and persistence ofSalmonella. Calcium phosphate, milk Ca, calcium carbonate and calcium chloride are able to enhance the intestinal resistance toSalmonellain rats.
Sinistral transport along the Trans-European Suture Zone: detrital zircon–rutile geochronology and sandstone petrography from the Carboniferous flysch of the Pontides
Authors: OKAY NİLGÜN , ZACK THOMAS , OKAY ARAL I. , BARTH MATTHIAS
Published: September 2010

The Lower Carboniferous flysch of the Istanbul Zone in Turkey is an over 1500 m thick turbiditic sandstone–shale sequence marking the onset of the Variscan deformation in the Pontides. It overlies Lower Carboniferous black cherts and is unconformably overlain by Lower Triassic continental sandstones and conglomerates. The petrography of the Carboniferous sandstones and the geochronology and geochemistry of the detrital zircons and rutiles were studied to establish the provenance of the clastic rocks. The sandstones are feldspathic to lithic greywackes and subgreywackes with approximately equal amounts of quartz, feldspar and lithic clasts. The amount of quartz and lithic fragments decreases upwards in the sequence at the expense of feldspar. The lithic fragments are dominated by intermediate volcanic rocks, followed by metamorphic and sedimentary rock fragments. Coarse lithic fragments are generally granitoidic. In the discrimination diagrams, sandstone samples lie mainly in the field of dissected arc. A total of 218 detrital zircons and 35 detrital rutiles from four sandstone samples were analysed with laser ablation ICP-MS. The detrital zircons show a predominantly bimodal age distribution with Late Devonian to Early Carboniferous (390 to 335 Ma) and Cambrian–Neoproterozoic (640 to 520 Ma) ages. The remaining 9 % of the analysed zircons are in the 1700–2750 Ma range; zircons of the 700–1700 Ma age range are absent. The REE patterns and Th/U ratios of the zircons are consistent with a magmatic origin. With one exception (Neoproterozoic), the rutile ages are Late Devonian–Early Carboniferous and their geochemistry indicates that they were derived from amphibolite-facies metamorphic rocks. Sandstone petrography and detrital zircon–rutile ages suggest one dominant source for the Lower Carboniferous sandstones: a Late Devonian to Early Carboniferous magmatic and metamorphic province with overprinted Neoproterozoic basement. Late Devonian–Early Carboniferous magmatic and metamorphic rocks are unknown from the Eastern Mediterranean region. They are, however, widespread in central Europe. The Istanbul Zone is commonly correlated with the Avalonian terrranes in central Europe, which collided with the Armorican terranes during Carboniferous times, resulting in the Variscan orogeny. The Carboniferous flysch of the Istanbul Zone must have been derived from a colliding Armorican terrane, as indicated by the absence of 700–1700 Ma zircons and by Late Devonian–Early Carboniferous magmatism, typical features of the Armorican terranes. This suggests that during Carboniferous times the Istanbul terrane was located close to the Bohemian Massif and has been translated by strike-slip along the Trans-European Suture Zone to its Cretaceous position north of the Black Sea.
In home or at home? How collective decision making in a new care facility enhances social interaction and wellbeing amongst older adults
Authors: KNIGHT CRAIG , HASLAM S. ALEXANDER , HASLAM CATHERINE
Published: September 2010

Benevolent, long-term care can threaten older adults' sense of autonomy in a residential home environment. Increasing reliance on a hotel style of living has been seen to erode social identity, life satisfaction and even survival or lifespan. Drawing on evidence from both gerontological and social psychological literature, this paper examines the links between the empowerment of residents and their subsequent quality of life in the context of a move into a new care facility in a medium-sized town in South-West England. A longitudinal experiment was conducted during which 27 residents on one floor of a new facility were involved in decisions surrounding its décor, while those on another floor were not. The residents' attitudes and behaviour were monitored at three points over five months (four weeks pre-move, four weeks post-move, and four months post-move). Consistent with the social identity literature, members of the empowered group reported increased identification with staff and fellow residents in the new home, displayed enhanced citizenship, reported improved wellbeing, and made more use of the communal space. Moreover the staff found the empowered residents to be more engaged with their environment and the people around them, to be generally happier and to have better health. These patterns were observed one month after the move and remained four months later. Some implications for theory and practice are discussed.
Closing the age gap? Age, skills and the experience of work in Great Britain
Authors: FELSTEAD ALAN
Published: September 2010

Populations across Europe are ageing as death rates among the old and fertility rates among the young fall. This produces a number of long-term challenges for national governments – most notably, coping with the increased demand for social services, pensions and benefits that must be funded by a declining proportion of working adults. One policy response has been to extend people's working lives, but we know relatively little about the skills and employment experiences of older workers and how these compare with younger workers. This paper sheds new light on this issue by examining whether older workers do less well than their younger counterparts in terms of the skills of the jobs they hold, the quality of their working lives, their commitment to their current employer and to employment in general, and their attitudes towards and experiences of training. The paper also assesses whether these age gaps have closed over time. The empirical evidence for the paper is from five separate but comparable surveys carried out in 1986, 1992, 1997, 2001 and 2006. Taken together, the five surveys provide information on the employment experiences of over 22,000 workers in Great Britain. This allows us to chart whether we are witnessing the disappearance of at least some of the age divisions in the labour market.
Capital market integration in Spain? Introducing the Bilbao Stock Exchange, 1891-1936
Authors: Houpt Stefan , Rojo Cagigal Juan Carlos
Published: September 2010

This paper presents the first results of our most recent research on the Bilbao Stock Exchange (BSE) from its foundation in 1890 up to the Spanish Civil War. We examine the origin of the Exchange and follow its evolution over the first half-century of existence. To this end we introduce some of the stock exchange indexes we have calculated for Bilbao and put them into comparative perspective with the existing series on general economic and industrial activity and the indexes for other Spanish exchanges for the period considered. These comparisons show Bilbao’s evolution from a public debt-dominated market to an industrial exchange very much tied to regional development. Finally, we contrast the degree of financial market integration associated with the existing Spanish exchange indexes. Our analysis finds strong support for considering the BSE index as an industrial index and little evidence of capital market integration between the principal Spanish exchanges before the 1920s.
Generic programming with C++ concepts and Haskell type classes—a comparison
Authors: BERNARDY JEAN-PHILIPPE , JANSSON PATRIK , ZALEWSKI MARCIN , SCHUPP SIBYLLE
Published: September 2010

Earlier studies have introduced a list of high-level evaluation criteria to assess how well a language supports generic programming. Languages that meet all criteria include Haskell because of its type classes and C++ with the concept feature. We refine these criteria into a taxonomy that captures commonalities and differences between type classes in Haskell and concepts in C++ and discuss which differences are incidental and which ones are due to other language features. The taxonomy allows for an improved understanding of language support for generic programming, and the comparison is useful for the ongoing discussions among language designers and users of both languages.
Pour un modèle diglossique de description du français: quelques implications théoriques, didactiques et méthodologiques
Authors: ZRIBI-HERTZ ANNE
Published: September 2010

Cet article défend l'hypothèse que le français (toutes zones géographiques confondues) présente aujourd'hui les propriétés caractérisant la situation diglossique, selon la définition classique de ce concept formulée par Ferguson (1959): la variété H est incarnée par la grammaire standard, et les variétés L par les grammaires appelées icidialectales, activées par les locuteurs en situation informelle. Dans une optique générative de la grammaire, il est proposé de représenter la compétence linguistique des francophones par deux grammaires en intersection, schéma rendant compte de l'intuition que les deux algorithmes génèrent “la même langue”. L'article s'emploie à justifier pour le français l'hypothèse diglossique et la formalisation proposée, et à en explorer quelques avantages et implications pour la description et l'enseignement de cette langue.
Popular Resistance in Communist Czechoslovakia: The Plzeň Uprising, June 1953
Authors: McDERMOTT KEVIN
Published: September 2010

This article examines an important, but little-known, event in the history of post-war Czechoslovakia: the Plzeň uprising of June 1953. After outlining the context, processes and outcomes of the revolt, I argue that the disorders were less an expression of ubiquitous political and ideological resistance to the communist regime than a reflection of the disastrous socio-economic conditions and the breakdown in relations between party and workers at the point of production. I also maintain that the conventional wisdom of the ‘Stalinised’ Communist Party of Czechoslovakia as a fully fledged ‘totalitarian’ party is in many ways wide of the mark. Finally, the uprising prompted the party's tentative turn towards a ‘New Course’ and eventually a strategy of ‘socialist consumerism’.
‘Anarchist Amazons’: The Gendering of Radicalism in 1970s West Germany
Authors: ROSENFELD ALAN
Published: September 2010

This article examines the intersection between reactions to urban guerrilla violence and anxieties over the women's liberation movement in 1970s West Germany. State officials and the mainstream press focused a disproportionate amount of attention on women's contributions to left-wing violence, claiming that female guerrillas suffered from an ‘excess of women's liberation’. However, while commentators juxtaposed domineering women with effeminate men, the actual experiences of women inside groups such as the Red Army Faction often featured expressions of male dominance. Evidence suggests that female guerrillas suffered more from a compulsion to self-sacrifice than excessive emancipation.
Compaction creep of wet granular calcite by pressure solution at 28°C to 150°C
Authors: Zhang Xiangmin , Spiers Christopher J. , Peach Colin J.
Published: September 2010

Uniaxial compaction experiments have been carried out on wet calcite powders prepared from milled limestone, analytical grade calcite, and superpure calcite. The tests were performed at 28°C–150°C, effective stresses of 20–47 MPa, and a pore pressure of 20 MPa, using presaturated CaCO3 solution as the pore fluid. Sample grain sizes ranged from 12 to 86 μm. The aim was to determine if creep occurs by intergranular pressure solution (IPS) under these conditions and to identify the rate‐controlling process. The wet samples showed significant creep, while dry and oil‐flooded samples did not. Wet samples were also characterized by microstructures such as sutured grain contacts, grain indentations, and overgrowths, suggesting the operation of IPS. The behavior of the wet samples at low strains (<4–5%) agreed well with the predictions of standard models for diffusion‐controlled pressure solution. However, at higher strains (5–10%), creep slowed down compared with the model predictions. Transient flow‐through tests performed in this regime led to an acceleration of creep, consistent with models for precipitation‐controlled IPS, and demonstrated an increase in the impurity content of the pore fluid toward higher strains. Since some of these impurities (notably Mg2+) retard precipitation in calcite, we suggest that creep occurred by diffusion‐controlled IPS at low strain, giving way to precipitation control at larger strains as impurities accumulated. Fitting of the diffusion‐controlled IPS model to the low strain data yielded values of the grain boundary diffusion product DS in calcite of ∼10−19 m3 s−1 at 150°C.
Triggering of a volcanic dome collapse by rainwater infiltration
Authors: Hicks Peter D. , Matthews Adrian J. , Cooker Mark J.
Published: September 2010

The thermodynamic processes in a one‐dimensional model of a porous lava dome are considered in the presence of a rising magmatic gas flux through the void spaces and rainfall interacting with the dome surface. The steady state surface temperature of the dome depends on both magmatic gas mass flux and rainfall rate. A critical rainfall rate is determined, that cools the dome surface to 100°C. Rainfall rates above this critical value allow liquid infiltration into the void spaces of the dome, thus restricting the escape of magmatic gas. A model which restricts the gas flow through the surface predicts internal gas pressures much higher than the overburden pressure in the top few meters, approximately one hour after the onset of rainfall. For a marginally stable dome, this could cause small Vulcanian explosions, which (depending on their location) could trigger a dome collapse, on a timescale consistent with observations.
Pn tomography of the western United States using USArray
Authors: Buehler Janine S. , Shearer Peter M.
Published: September 2010

USArray has now provided several years of high‐quality seismic data and improved ray coverage for much of the western United States, which will enable increased resolution for studies of the lithospheric and deeper structure of the North American continent. Here we analyze Pn arrival times from the transportable stations of USArray to resolve crustal thickness and uppermost mantle structure. We use 123,008 Pn picks from April 2004 to October 2009 as measured by the Array Network Facility at epicentral distances from 180 to 1450 km. These picks are derived from 778 stations at ∼70 km spacing and 7903 earthquakes and quarry blasts. Applying the classic time‐term method, we use a regularized least squares inversion to estimate crustal thickness variations and image velocity perturbations in the uppermost mantle just below the Moho. We also consider upper mantle anisotropy and describe the velocity perturbations with a cos 2ϕ azimuthal variation. Our crustal thickness map generally agrees with receiver function results from other researchers but differs in some details. We obtain an average upper mantle velocity of 7.93 km/s, with higher velocities beneath eastern Washington and northern Idaho, and lower velocities near the California‐Mexico border, the Sierra Nevada, the northern coastal California region, and the greater Yellowstone area. We observe large anisotropic anomalies in southern California as well as in the Snake River Plain area. These results should complement other seismic studies (e.g., body and surface wave tomography and shear wave splitting) to provide information about composition, temperature, and tectonic processes in the western United States.
Recent behavior of the North Anatolian Fault: Insights from an integrated paleoseismological data set
Authors: Fraser J. , Vanneste K. , Hubert‐Ferrari A.
Published: September 2010

The North Anatolian Fault (NAF) is a right‐lateral plate boundary fault that arcs across northern Turkey for ∼1500 km. Almost the entire fault progressively ruptured in the 20th century, its cascading style indicating that stress from one fault rupture triggers fault rupture of adjacent segments. Using published paleoseismic investigations, this study integrates all of the existing information about the timing of paleoearthquakes on the NAF. Paleoseismic investigation data are compiled into a database, and for each site a Bayesian, ordering‐constrained age model is constructed in a consistent framework. Spatial variability of recurrence intervals suggests a spatial pattern in the behavior of earthquakes on the NAF that may correspond to the tectonic provinces within the Anatolian plate. In the west, the shear stress associated with the escaping Anatolian plate interplays with the tensile stress associated with the Aegean extensional province. Along this western transtensional section we recognize short recurrence intervals and switching between the furcated fault strands. The central section of the NAF is translational with little influence of fault‐normal stresses from other tectonic sources. This section tends to rupture in unison or close succession. The eastern section of the NAF is transpressional due to the compressional fault‐normal stress associated with the indenting Arabian plate. Along this section the recurrence intervals are bimodal, which we attribute to variable normal stress, although there are other possible causes.
Predicting North Atlantic sea surface temperature variability on the basis of the first‐mode baroclinic Rossby wave model
Authors: Zhang Honghai , Wu Lixin
Published: September 2010

Predictability of sea surface temperature (SST) variations over the North Atlantic Ocean is studied on the basis of the first‐mode baroclinic Rossby wave model. This simple linear wave model can explain about 10%∼46% of the wintertime SST variability in several regions of the North Atlantic basin, including the tropics between 5°N and 20°N, the eastern subtropics between 27°N and 34°N, and the east of Newfoundland. It is shown that the wintertime SST anomalies can be skillfully predicted up to 3 months ahead in the tropical Atlantic, 18 months in the eastern subtropical Atlantic, and 3 years east of Newfoundland on the basis of the first‐mode baroclinic Rossby wave adjustment.
Normalized radar cross section of the sea for backscatter: 1. Mean levels
Authors: Plant William J. , Keller William C. , Hayes Kenneth , Chatham Gene
Published: September 2010

The normalized radar cross section of the sea for backscatter, σo, is investigated for incidence angles between 0° and 89° using data collected over more than two decades. The most recent measurements were made from several ships using a coherent, dual‐polarized, X band radar. These measurements show that vertically polarized transmit and receive signals, σo(VV), at high incidence angles exhibit wind speed and azimuth angle dependence similar to those at lower incidence angles. They are nearly as large looking downwind as they are looking upwind and minimize near the crosswind direction. Horizontally polarized transmit and receive signals, σo (HH), behave differently at high incidence angles. They are largest looking upwind and smallest looking downwind. Fits of the multiscale model of microwave backscatter from the ocean to these data along with data collected previously at lower incidence angles show that over the whole range of incidence angles from 0° to 89°, σo(VV) is explained by the model, while measured σo(HH) values are generally higher than the model predicts at incidence angles above about 45°. Thus scattering phenomena exist on the ocean surface that affect HH backscatter very strongly at the higher incidence angles while impacting VV‐polarized backscatter only slightly. This conclusion is strengthened by our observation of high‐incidence‐angle backscatter from the ocean where mean σo(HH) exceeds mean σo(VV) by as much as 15 dB. We examine phenomena that might account for this behavior and suggest that multipath dihedral‐type features are likely to be important scatterers since they produce large σo(HH)/σo(VV) owing to Brewster damping of the first VV bounce.
Aeolian sediment fluxes measured over various plant/soil complexes in the Chihuahuan desert
Authors: Bergametti G. , Gillette D. A.
Published: September 2010

Measurements of horizontal flux of sediment were performed over the period 1998–2005 at different vegetated areas within the Jornada Long Term Ecological Research site. Sediment trap samples were collected during successive nominal 3‐month periods at 15 sites: three independent sites at each of the five dominant plant/soil complexes encountered in this part of the Chihuahuan desert (mesquite, creosote, tarbush, grama grass, and playa grass). Mesquite vegetated areas have significantly higher sediment fluxes than the four other plant/soil complexes. The other types of vegetation complexes yield sediment fluxes that cannot be statistically distinguished from each other. An analysis of the temporal variability of the sediment fluxes indicates that only the annual sediment fluxes from mesquite sites are correlated with the annual occurrence of high wind speeds. Examination of the vertical profile of the fluxes of sediment and the fast response Sensit measurements confirms that a local saltation mechanism is responsible for sediment fluxes measured at mesquite sites. However, the local saltation mechanism cannot explain sediment fluxes measured on nonmesquite sites. Sediment fluxes at nonmesquite sites are only rarely carried in from upwind sources. Additionally, our data for sediment flux showed that off‐site (drifting in) flux of sediment cannot explain the differences of mesquite and nonmesquite sediment fluxes. We suggest dust devils to be the mechanism that causes sediment emissions at both nonmesquite and mesquite lands, but their effect is trivial compared to the fluxes caused by mesoscale meteorological winds at the mesquite sites.
Monitoring deformation from hydrologic processes in a karst aquifer using long‐baseline tiltmeters
Authors: Jacob Thomas , Chéry Jean , Boudin Frédéric , Bayer Roger
Published: September 2010

The aim of this study is to bring new information on water storage dynamics in karst systems from tiltmeter measurements. Newly developed long‐base hydrostatic tiltmeters are installed at two sites on the Larzac plateau (France) in a karst aquifer of ∼100 km2 recharge area. Each site is located within a karst cave where two tilt directions are monitored. Significant reversible tilt deformation reaching amplitudes of 10−6 to 10−5 rad was observed at both sites following heavy precipitation. Elastic parameters were determined with an experiment in which a tiltmeter site was loaded by up to 25 t of weight at strategic locations at the ground surface. Mechanisms responsible for the observed tilt were then examined by means of finite element modeling. Deformation induced by water pressure changes in fractures is our preferred interpretation as the most plausible mechanism. Within this scope, we used the tiltmeter responses to extract time constants using lumped parameter modeling. Time constants are interpreted to be associated with the filling and emptying of fractures nearby the tiltmeters. These instruments therefore appear as useful tools to study the local dynamics of water infiltration in karst systems.
A 1‐D morphodynamic model for rill erosion
Authors: Papanicolaou Athanasios N. , Sanford John T. , Dermisis Dimitrios C. , Mancilla Gabriel A.
Published: September 2010

The key objective of this paper is to develop a 1‐D hydrodynamic and sediment transport model, namely, RILL1D, that handles transcritical flows over abrupt changes (e.g., formation of pool crests and width change) in a single rill and also predicts changes in rill bed elevation. Replication of rill conditions in terms of flow and bed evolution changes necessitated the use of an enhanced TVD‐MacCormack scheme with implementation of Tseng's surface gradient method, to provide an oscillation free solution over formed pool crests. The model at the end of each time step calculates the flow depth, velocity, and bed shear stress and provides changes in bed elevation and grain size distribution within a cell. The hydrodynamic performance of RILL1D is evaluated by comparing its results with either analytical solutions or experimental observations from various benchmark tests with rigid bed conditions that include (1) formation of a hydraulic jump in a rectangular channel, (2) steady subcritical and transcritical flow (without a shock) over a hump, (3) formation of a hydraulic jump in a converging‐diverging frictionless channel, and (4) flows over step‐pools. It is shown that the enhanced TVD‐MacCormack scheme adequately simulates transcritical flows by preserving the mass conservation and reducing the artificial numerical error. The scheme also approximates satisfactorily depth and velocity for a single rill, with a fixed bed consisting of steps and pools, except near the pool headwalls where a backroller forms with negative velocities. The sediment component of RILL1D is evaluated by two field investigations of single rills with mobile beds. With the field data the code is tested for its ability to reproduce measured values of sediment transport rates. A sensitivity analysis is performed to assess the effects of cell size and critical erosional strength in the predictive ability of the model. RILL1D performs reasonably well in these simulations in terms of sediment prediction rates and fared adequately in terms of replicating rill bed morphology.
An ensemble conditional nonlinear optimal perturbation approach: Formulation and applications to parameter calibration
Authors: Tian Xiangjun , Xie Zhenghui , Dai Aiguo
Published: September 2010

The conditional nonlinear optimal perturbation (CNOP) method proposed by Mu et al. (2003) has been a useful tool for studying predictability dynamics. Its further applications are, however, hampered by the need of an adjoint model. Aiming to solve this problem, an ensemble conditional nonlinear optimal perturbation (EnCNOP) approach is proposed in this paper by merging the Monte Carlo method and the proper orthogonal decomposition (POD) technique into the CNOP to transform an implicit optimization problem into an explicit one. This approach is further formulated for parameter calibration. Numerical experiments with a 1‐D model of the soil water equation show that the EnCNOP approach outperforms a dual‐pass optimization framework on the basis of the ensemble Kalman filter (EnKF) and a shuffled complex evolution approach (SCE‐UA) in terms of both increasing the calibration precision and reducing the computational costs. In particular, the EnCNOP approach outperforms the SCE‐UA when only an approximate value range of the input parameters is known. Our EnCNOP method is further implemented within a complicated highly nonlinear land surface model (namely, NCAR CLM3) and evaluated through a case study which illustrates its applicability to complex, highly nonlinear problems.
Effect of strong heterogeneity on the onset of convection in a porous medium: Importance of spatial dimensionality and geologic controls
Authors: Simmons Craig T. , Kuznetsov A. V. , Nield D. A.
Published: September 2010

The effect of strong heterogeneity on the onset of convection induced by a vertical density gradient in a saturated heterogeneous porous medium governed by Darcy's law is investigated. A computer package has been developed to study the applicability of an average Rayleigh number as a criterion for the onset of convection in strongly heterogeneous geologic media. The heterogeneous geologic media have been described using random spatial functions for the permeability field which are lognormally distributed and spatially correlated. Both isotropic and anisotropic correlation lengths within the geologic structure are considered. This paper presents the first 3D theoretical treatment of the conditions for the onset of convection (Rayleigh stability criteria) in strongly heterogeneous porous media. We elucidate the critical role that spatial dimensionality (2D versus 3D flow) plays in controlling convection processes and stability criteria. Our results quantitatively demonstrate for the first time that spatial dimensionality is a dominant control on the onset of convection in a strongly heterogeneous geologic medium. Unbounded Rayleigh number behavior is observed in 3D. This leads to the important new conclusion that a Rayleigh number (based on mean quantities) is unlikely to be a valid predictor for the onset of convection in 3D strongly heterogeneous porous media. Furthermore, we systematically and quantitatively demonstrate that the onset of convection in a heterogeneous geologic medium is highly sensitive to changes in the standard deviation of the lognormal permeability field, moderately sensitive to changes in the level of correlation length, and relatively insensitive to the anisotropy of correlation length.
Reduction of the usable wind‐work on the general circulation by forced symmetric instability
Authors: Thomas L. N. , Taylor J. R.
Published: September 2010

Winds aligned with geostrophic currents input energy into the ocean circulation. For baroclinic, surface‐intensified currents, winds of this orientation (i.e., down‐front winds) reduce the potential vorticity in the mixed layer, making the flow susceptible to symmetric instability (SI). SI is a submesoscale shear instability that draws its energy from baroclinic, geostrophic currents. High‐resolution numerical simulations are used to demonstrate how forced SI driven by down‐front winds extracts energy from the geostrophic flow at a rate proportional to the Ekman buoyancy flux, the dot product of the Ekman transport and the surface buoyancy gradient. The kinetic energy (KE) going into SI is converted to 3D turbulence through a secondary shear instability and ultimately dissipated at small scales. Thus under the conditions where winds input KE to the circulation, some of the KE of baroclinic currents is dissipated by this mechanism. The net result of this submesoscale sink of KE is to reduce the usable wind‐work, i.e., the wind‐induced rate of KE increase, by an amount that depends on the wind‐stress and the change in geostrophic velocity across the mixed layer.
Seismic interaction and delayed triggering along the North Anatolian Fault
Authors: Durand V. , Bouchon M. , Karabulut H. , Marsan D. , Schmittbuhl J. , Bouin M.‐P. , Aktar M. , Daniel G.
Published: September 2010

The deformation of northwestern Turkey is the result of the encounter of the westward extrusion of the Anatolian plate with the north‐south extension of the Aegean domain. While the North Anatolian Fault localizes the former type of deformation and has been the site of more large earthquakes (9 events of magnitude ≥7) than any other continental fault over the past 100 years, the extension is diffuse and is characterized by spatial clusters of smaller earthquakes and near‐continuous activity. We study the evolution of seismicity along the fault and in the clusters neighboring the fault before and after the two large earthquakes of 1999. We observe that the un‐ruptured section of the fault and the extension clusters respond very differently to the earthquakes. While significant aftershock activity on the fault segments adjacent to the rupture only occurs at relatively short distance from the rupture (≤30 km), the clusters can be activated at much larger distances (300 km). Remarkably their triggering is not immediate after the earthquake but is delayed in time. Their peak seismic activation may occur weeks or months after the earthquake. This distant and delayed triggering, which is consistent with recent GPS observations, may help resolve some of the previously unexplained characteristics of the 1939–1999 sequence of large earthquakes along the fault.