bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving non‐contrast‐enhanced steady‐state free precession angiography with compressed sensing
Authors: Çukur Tolga , Lustig Michael , Nishimura Dwight G.
Published: February 2009

Flow‐independent angiography offers the ability to produce vessel images without contrast agents. Angiograms are acquired with magnetization‐prepared three‐dimensional balanced steady‐state free precession sequences, where the phase encodes are interleaved and the preparation is repeated before each interleaf. The frequent repetition of the preparation significantly decreases the scan efficiency. The number of excitations can instead be reduced with compressed sensing by exploiting the compressibility of the angiograms. Hence, the phase encodes can be undersampled to save scan time without significantly degrading image quality. These savings can be allotted for preparing the magnetization more often, or alternatively, improving resolution. The enhanced resolution and contrast achieved with the proposed method are demonstrated with lower leg angiograms. Depiction of the vasculature is significantly improved with the increased resolution in the phase‐encode plane and higher blood‐to‐background contrast. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Velocity recovery cycles of human muscle action potentials and their sensitivity to ischemia
Authors: Z'Graggen Werner J. , Bostock Hugh
Published: February 2009

This study was undertaken to test whether recovery cycle measurements can provide useful information about the membrane potential of human muscle fibers. Multifiber responses to direct muscle stimulation through needle electrodes were recorded from the brachioradialis of healthy volunteers, and the latency changes measured as conditioning stimuli were applied at interstimulus intervals of 2–1000 ms. In all subjects, the relative refractory period (RRP), which lasted 3.27 ± 0.45 ms (mean ± SD, n = 12), was followed by a phase of supernormality, in which the velocity increased by 9.3 ± 3.4% at 6.1 ± 1.3 ms, and recovered over 1 s. A broad hump of additional supernormality was seen at around 100 ms. Extra conditioning stimuli had little effect on the early supernormality but increased the later component. The two phases of supernormality resembled early and late afterpotentials, attributable respectively to the passive decay of membrane charge and potassium accumulation in the t‐tubules. Five minutes of ischemia progressively prolonged the RRP and reduced supernormality, confirming that these parameters are sensitive to membrane depolarization. Velocity recovery cycles may provide useful information about altered muscle membrane potential and t‐tubule function in muscle disease. Muscle Nerve, 2008
A three‐dimensional integral equation model for calculating poro‐ and thermoelastic stresses induced by cold water injection into a geothermal reservoir
Authors: Zhou X. X. , Ghassemi A. , Cheng A. H.‐D.
Published: February 2009

Poro‐mechanical and thermo‐mechanical processes change the fracture aperture and thus affect the water flow pattern in the fracture during the cold water injection into enhanced geothermal systems (EGS). In addition, the stresses generated by these processes contribute to the phenomenon of reservoir seismicity. In this paper, we present a three‐dimensional (3D) partially coupled poro‐thermoelastic model to investigate the poroelastic and thermoelastic effects of cold water injection in EGS. In the model, the lubrication fluid flow and the convective heat transfer in the fracture are modeled by the finite element method, while the pore fluid diffusion and heat conductive transfer in the reservoir matrix are assumed to be 3D and modeled by the boundary integral equation method without the need to discretize the reservoir. The stresses at the fracture surface and in the reservoir matrix are obtained from the numerical model and can be used to assess the variation of in situ stress and induced seismicty with injection/extraction. Application of the model shows that rock cooling induces large tensile stresses and increases fracture conductivity, whereas the rock dilation caused by fluid leakoff decreases fracture aperture and increases compressive total stresses around the injection zone. However, increases in pore pressure reduce the effective stresses and can contribute to rock failure, fracture slip, and microseismic activity. Copyright © 2009 John Wiley & Sons, Ltd.
Predicting who will benefit from treatment
Authors: Herbison Peter
Published: February 2009

It is often of interest whether some subgroup either responds better, or does not respond at all, to a treatment. To decide this requires a subgroup analysis. The best way to do this is as part of an individual patient data meta‐analysis. To facilitate these there is a need for repositories for individual data from randomized controlled trials. Neurourol. Urodynam. 28:168–169, 2009. © 2009 Wiley‐Liss, Inc.
Hybrid‐Trefftz stress elements for incompressible biphasic media
Authors: de Freitas J. A. Teixeira , Toma M.
Published: February 2009

A wavelet‐based, high‐order time integration method is applied to replace the parabolic problem governing the response of incompressible biphasic media by a set of uncoupled Helmholtz problems. Their formal solutions are used to formulate the stress model of the hybrid‐Trefftz finite element formulation. The stress, pressure and displacement fields are directly approximated and designed to satisfy locally the equilibrium condition in each phase of the mixture. This basis is used to enforce on average the compatibility conditions and the constitutive relations of the mixture. The displacements in the solid and the normal displacement in the fluid are approximated independently on the boundary of the element and the basis is used to enforce in weak form the boundary equilibrium conditions. The resulting solving system is sparse, well suited to adaptive refinement and parallel processing. The energy statements associated with the formulation are recovered and sufficient conditions for the uniqueness of the finite element solutions are stated. Testing problems reported in the literature are used to illustrate the quality of the pressure, stress, displacement and velocity estimates obtained with the hybrid‐Trefftz stress element. Copyright © 2009 John Wiley & Sons, Ltd.
A hybrid collocation/Galerkin scheme for convective heat transfer problems with stochastic boundary conditions
Authors: Constantine Paul G. , Doostan Alireza , Iaccarino Gianluca
Published: February 2009

We present a numerical method to study convective heat transfer in a high Reynolds number incompressible flow around a cylinder subject to uncertain boundary conditions. We exploit the one‐way coupling of the energy and momentum transport to derive a semi‐intrusive uncertainty propagation scheme, which combines Galerkin and collocation approaches for computing approximate statistics of the stochastic temperature field. The hybrid scheme converges rapidly and dramatically reduces the overall computational cost compared with the conventional uncertainty propagation schemes. Copyright © 2009 John Wiley & Sons, Ltd.
A time‐integration method for the viscoelastic–viscoplastic analyses of polymers and finite element implementation
Authors: Kim Jeong Sik , Muliana Anastasia H.
Published: February 2009

The present study introduces a time‐integration algorithm for solving a non‐linear viscoelastic–viscoplastic (VE–VP) constitutive equation of isotropic polymers. The material parameters in the constitutive models are stress dependent. The algorithm is derived based on an implicit time‐integration method (Computational Inelasticity. Springer: New York, 1998) within a general displacement‐based finite element (FE) analysis and suitable for small deformation gradient problems. Schapery's integral model is used for the VE responses, while the VP component follows the Perzyna model having an overstress function. A recursive‐iterative method (Int. J. Numer. Meth. Engng 2004; 59:25–45) is employed and modified to solve the VE–VP constitutive equation. An iterative procedure with predictor–corrector steps is added to the recursive integration method. A residual vector is defined for the incremental total strain and the magnitude of the incremental VP strain. A consistent tangent stiffness matrix, as previously discussed in Ju (J. Eng. Mech. 1990; 116:1764–1779) and Simo and Hughes (Computational Inelasticity. Springer: New York, 1998), is also formulated to improve convergence and avoid divergence. Available experimental data on time‐dependent and inelastic responses of high‐density polyethylene are used to verify the current numerical algorithm. The time‐integration scheme is examined in terms of its computational efficiency and accuracy. Numerical FE analyses of microstructural responses of polyethylene reinforced with elastic particle are also presented. Copyright © 2009 John Wiley & Sons, Ltd.
Microencapsulation of hydrophilic solid powder as a flame retardant with epoxy resin by using interfacial reaction method
Authors: Takahashi Masanori , Taguchi Yoshinari , Tanaka Masato
Published: February 2009

Microencapsulation of Bistetrazol · diammonium (BHT · 2NH3) as a hydrophilic powdery flame retardant was tried by the interfacial reaction method in reverse emulsion. In this microencapsulation method, water droplets containing BHT · 2NH3 and hydrazine as gelation agent for epoxy resin were dispersed in the continuous phase of corn oil. When epoxy resin was added to the continuous phase, BHT · 2NH3 as a core material was microencapsulated by the reaction of epoxy resin with hydrazine on the interface between the surface of water droplet and the continuous phase. The content of the core material from 70 to 85%, and the microencapsulation efficiency from 89 to ca 100% were able to be attained under the experimental conditions adopted here. Copyright © 2009 John Wiley & Sons, Ltd.
Neonatal alloimmune thrombocytopenia and neutropenia associated with maternal human leukocyte antigen antibodies
Authors: Gramatges M. Monica , Fani Pauline , Nadeau Kari , Pereira Shalini , Jeng Michael R.
Published: February 2009

Neonatal thrombocytopenia or neutropenia may result from passive transfusion of maternally derived antibodies. Antibodies against platelet antigens are commonly associated with neonatal alloimmune thrombocytopenia (NAIT), and anti‐neutrophil antibodies are frequently identified in alloimmune neonatal neutropenia (ANN). Combined alloimmune cytopenias in the newborn are rarely reported; even fewer reports document human leukocyte antigen (HLA) antibodies as a potential cause of neonatal thrombocytopenia or neutropenia. We describe neutropenia and thrombocytopenia in a newborn associated with markedly elevated maternal HLA antibodies in the absence of anti‐neutrophil or anti‐platelet antibodies to highlight consideration of HLA antibodies in the pathogenesis of ANN and NAIT. Pediatr Blood Cancer 2009;53:97–99. © 2009 Wiley‐Liss, Inc.
Role of the interphase in the flow stability of reactive coextruded multilayer polymers
Authors: Lamnawar Khalid , Maazouz Abderrahim
Published: February 2009

Coextrusion technologies are commonly used to produce multilayered composite sheets or films for a large range of applications from food packaging to optics. The contrast of rheological properties between layers can lead to interfacial instabilities. Important theoretical and experimental advances regarding theses defects have, during the last decades, been made using a mechanical and numerical approach. This study deals with the influence of the physicochemical affinity between the neighboring layers on interfacial instabilities for functionalized incompatible polymers. It was experimentally confirmed, in this case, that weak disturbance can be predicted by considering an interface of nonzero thickness (corresponding to an interdiffusion/reaction zone interphase) instead of a purely geometrical interface between the two reactive layers. According to the rheological investigations, an experimental strategy was here formulated to investigate the parameters that controlled the stability of the reactive multilayer flows. The role of the viscosity ratio, elasticity ratio, and layer ratio of the stability of the interface was also investigated coupling to the reaction rate/compatibilization phenomenon. Hence, based on this analysis, guidelines for a stable coextrusion of reactive functionalized polymers can be provided coupling the classical parameters and the physicochemical affinity at the polymer/polymer interface. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
A framework for testing global non‐hydrostatic models
Authors: Wedi Nils P. , Smolarkiewicz Piotr K.
Published: February 2009

With the emergence of non‐hydrostatic global dynamical cores, an alternative testing strategy is proposed, where the planetary radius is suitably reduced to capture non‐hydrostatic phenomena without incurring the computational cost of actual simulations of weather and climate at non‐hydrostatic resolution. The procedure is simple and tests various aspects of the discretized hydrostatic and non‐hydrostatic equations in the same setting on a sphere. Furthermore, it facilitates verification against Cartesian‐domain analytic solutions and against large‐eddy simulation (LES) benchmarks available for limited‐area models. The proposed framework is illustrated with examples of inertia–gravity wave dynamics in linear and nonlinear regimes, including flows past idealized mountains, stratified shear flows and critical layers. Finally, an intercomparison of the Held–Suarez climate variability for reduced‐size planets is presented, which provides a path for future investigations on the dynamics of convective boundary layers on a sphere. This assesses the ability to adequately capture interactions of large‐scale dynamics with intermittent turbulent structures, an important aspect of future weather and climate predictions. Copyright © 2009 Royal Meteorological Society
Intramolecular hydrogen bonding in structural conformers of 2‐amino methylene malonaldehyde: AIM and NBO studies
Authors: Raissi H. , Jalbout A. F. , Yoosefian M. , Fazli Mustapha , Nowroozi A. , Shahinin M. , De Leon A.
Published: February 2009

The molecular structure and intramolecular hydrogen bond energies of 44 conformers of 2‐Amino methylene malonaldehyde were investigated at MP2 and B3LYP levels of theory using the standard 6‐311++G** basis set and AIM and NBO analysis. The calculated geometrical parameters and conformational analysis in gas phase show that the closed ring via intramolecular hydrogen bonded conformers of this compound are more stable than the other ones. Hydrogen bond energies for H‐bonded conformers were obtained from the related rotamers method (RRM) and Schuster method, and also the nature of H‐bonding of them has been investigated by means of the Bader theory of atoms in molecules, which is based on topological properties of the electron density. Delocalization effects can be identified from the presence of off diagonal elements of the Fock matrix in the NBO basis. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Dopaminergic synapses in the caudate of subjects with schizophrenia: Relationship to treatment response
Authors: Roberts Rosalinda C. , Roche Joy K. , Conley Robert R. , Lahti Adrienne C.
Published: February 2009

The typical symptoms of schizophrenia (SZ) are psychotic symptoms (hallucinations, delusions, disorders of thought or speech, grossly disorganized behavior) as well as cognitive impairments and negative symptoms. Not all patients respond to treatment and in those who do, only psychotic symptoms are usually improved. Imaging studies have shown that SZ subjects with high striatal dopamine release are far more responsive to antipsychotic drugs than those patients who have dopamine levels lower than or comparable to that of normal controls. In the present study we hypothesized that there was a link between psychosis and the number of dopaminergic synapses in the caudate nucleus in SZ. We examined dopaminergic synapses at the electron microscopic level in postmortem caudate from cases obtained from the Maryland Brain Collection. SZs were subdivided based on treatment response or resistance. The tissue was processed for the immunocytochemical localization of tyrosine hydroxylase (TH), the synthesizing enzyme for dopamine, and prepared for electron microscopy. The density of all TH labeled synapses was 43% greater in treatment responders than in controls and 62% greater in than in treatment resistant SZ. Axodendritic, but not axospinous, TH‐labeled synapses showed this increase. TH‐labeled axodendritic synapses in treatment responders were elevated in density (1.95 ± 0.093/10 μm3) compared to treatment resistant SZ (0.04 ± 0.017/10 μm3) and controls (0.11 ± 0.044/10 μm3). The results of the present study suggest that one anatomical underpinning of good treatment response may be a higher density of dopaminergic synapses and support a biological basis to treatment response and resistance. Moreover, these data have important implications for linking specific neuropathology with particular symptoms. Synapse 63:520–530, 2009. © 2009 Wiley‐Liss, Inc.
Lymphatic Invasion: An Important Prognostic Factor for Stages T1b–T3 Gallbladder Cancer and an Indication for Additional Radical Resection of Incidental Gallbladder Cancer
Authors: Shibata Kohei , Uchida Hiroki , Iwaki Kentaro , Kai Seiichiro , Ohta Masayuki , Kitano Seigo
Published: February 2009

Background

Laparoscopic cholecystectomy is being performed with increasing frequency worldwide. This has led to more frequent discovery of incidental gallbladder cancer (IGBC) and in turn to the need for an independent prognostic factor for stages T1b–T3 gallbladder cancer so that is can be determined clinically which cases of IGBC are indicated for additional radical resection (ARR).

Methods

A retrospective study was conducted that included 72 patients who underwent macroscopically curative surgical resection (R0, R1) at our center for stages T1b–T3 GBC. Survival analysis was performed, and the usefulness of ARR was analyzed in 15 patients with IGBC.

Results

Univariate analysis of disease‐specific survival showed stage T3, histologic grade II–IV, lymphatic invasion, vessel invasion, perineural invasion, lymph node metastasis, and a positive resection margin to be factors indicative of poor prognosis. Independent predictors of poor disease‐specific survival were stage T3 (hazard ratio, 2.33 [95% CI, 1.10–4.95]), lymphatic invasion (5.97 [1.29–27.6]), and a positive resection margin (3.17 [1.51–6.63]). Among the 15 IGBC patients, 4 of 5 patients without lymphatic invasion were cured, 2 of whom underwent cholecystectomy alone; 4 of 10 patients with lymphatic invasion did not undergo ARR, and the cancer recurred in all 4 patients; the other 6 patients underwent ARR, and 4 of them were cured by reoperation.

Conclusions

Lymphatic invasion well reflects the malignant phenotype of stages T1b–T3 GBC. We advocate ARR for IGBC patients with lymphatic invasion.
Adolescents’ explanations for romantic dissolutions: A developmental perspective
Authors: Connolly Jennifer , McIsaac Caroline
Published: February 2009

Our objective was to examine the prevalence and developmental significance of romantic break‐ups in adolescence, a relatively unexplored area of study. We examined their occurrence in a sample of 910 adolescents, first noting the frequency of these events across age, gender, and romantic experience, and then analyzing the dissolution explanations provided by a subsample (N = 211) who experienced a break‐up within the past 6 months. Break‐ups were reported by 23% of youth, especially those with extensive romantic experience. Most were described as self‐initiated, especially by girls. Using a categorical‐content approach, we determined that the majority of dissolution explanations reflected “fit failures” in meeting developmentally salient romantic needs, especially those related to interdependence. Patterns were consistent across gender and age, however, those with romantic experience focused most on unmet intimacy needs. We discuss the developmental significance of break‐ups, noting continuity between the needs expressed in intact and dissolving relationships.
Female-induced increase of host-plant volatiles enhance specific attraction of aphid maleDysaphis plantaginea(Homoptera: Aphididae) to the sex pheromone
Authors: van Tol R.W.H.M. , Helsen H.H.M. , Griepink F.C. , de Kogel W.J.
Published: February 2009

All aphid species studied so far share the same sex pheromone components, nepetalactol and nepetalactone. Variation by different enantiomers and blends of the two components released by different aphid species are limited and can only partially explain species-specific attraction of males to females. While some host-plant odours are known to enhance specific attraction of aphid species, herbivore-induced plant volatiles that synergise attractiveness to the sex pheromone are unknown. Here, we demonstrate that for the host-alternating rosy apple aphid (Dysaphis plantaginea(Passerini)) specificity of attraction of males to females is triggered by female-induced tree odours in combination with a 1:8 ratio of (4aS,7S,7aR)-nepetalactone and (1R,4aS,7S,7aR)-nepetalactol. Female aphid infestation induces increased release of four esters (hexyl butyrate, (E)-2-hexenyl butyrate, (Z)-3-hexenyl 3-methylbutyrate and hexyl 2-methylbutyrate) from apple leaves. Two different combinations of three esters applied in a 1:1:1 ratio increase the number of maleD. plantagineaand decrease the number of other aphid species caught in water traps in the presence of the pheromone components. The ester blend alone was not attractive. Combination of the pheromone blend with each single ester was not increasing attraction of maleD. plantaginea. The demonstration that sexual aphid species use herbivore-induced plant volatiles as a species-specific attractant for mate finding adds a new dimension to our understanding of insect species using or manipulating chemical cues of host plants for orientation.
A SURVEY OF FACTORS ASSOCIATED WITH THE ADOPTION OF ZERO TILLAGE WHEAT IN THE IRRIGATED PLAINS OF SOUTH ASIA
Authors: ERENSTEIN OLAF , FAROOQ UMAR
Published: February 2009

There is a quest for resource-conserving technologies that can save water, reduce production costs and improve production to address the slow down in productivity growth in the Indo-Gangetic Plains, the cereal bowl of South Asia. Findings from farm surveys are used to evaluate the farm household factors that affect the adoption of zero tillage (ZT) wheat in the rice-wheat systems of India's Haryana State and Pakistan's Punjab province. Three adoption classes are distinguished in each site: ZT adopters, dis-adopters and non-adopters. Bivariate analysis shows that adopters typically have the most favourable values for most of the indicators compiled and the non-adopters the least favourable, with dis-adopters often taking an intermediate position. The study highlights that ZT adoption in the initial diffusion stage is strongly linked to the wealth of the farm household. This indicates the need for closer consideration of equity implications in future research and development. The structural differences between adoption categories also easily confound the assessment of ZT impact.
The contributions of phonology, orthography, and morphology in Chinese–English biliteracy acquisition
Authors: WANG MIN , YANG CHEN , CHENG CHENXI
Published: February 2009

This study investigated the concurrent contributions of phonology, orthography, and morphology to biliteracy acquisition in 78 Grade 1 Chinese–English bilingual children. Conceptually comparable measures in English and Chinese tapping phonological, orthographic, and morphological awareness were administered. Word reading skill in English and Chinese was also tested. We found that cross-language phonological and morphological transfer occurs when acquiring two different writing systems. Chinese tone and onset awareness explained a significant amount of unique variance in English real-word reading after controlling for English-related variables. Chinese onset awareness alone made a significant unique contribution to variance in English pseudoword reading. Furthermore, English compound structure awareness explained unique variance in Chinese character reading. However, we did not see a significant cross-language transfer at the orthographic level. Taken together, these results suggest that there are shared phonological and morphological processes in bilingual reading acquisition, whereas the orthographic process may be language specific.
Does desiccation risk drive the distribution of juvenile cane toads (Bufo marinus) in tropical Australia?
Authors: Child Travis , Phillips Benjamin L. , Shine Richard
Published: February 2009

Immediately after their transition from aquatic to terrestrial life, juveniles of many anuran species are restricted to the margins of natal ponds. Understanding the factors determining the duration of that pondside aggregation has direct management ramifications in the case of the invasive cane toad (Bufo marinus) in tropical Australia. Previous work suggests that dispersal confers biotic advantages (reduced risk of cannibalism, enhanced feeding opportunities) to juvenile toads, but desiccation risk constrains these small animals to the moist margins of the pond. If so, juvenile dispersal should be sensitive to fluctuating hydric conditions on a diel and seasonal cycle. We tested this prediction with field observations (monitoring of dispersal to and from the pond) and field experiments (manipulating hydric regimes). Our results support a dynamic model of juvenile distribution, with a primary role for temporal variations in desiccation risk as the primary factor driving dispersal. During the dry season, strong diel cycles in desiccation risk generate a ‘tidal’ flow of juveniles, dispersing out in the moist morning but retreating to the pond margins at midday. Dispersal rates were enhanced by artificial watering during the dry season, and by the onset of the wet season.
Floral biology, breeding systems and population genetic structure of three climbingBauhiniaspecies (Leguminosae: Caesalpinioideae) in Hong Kong, China
Authors: Lau Carol P. Y. , Saunders Richard M. K. , Ramsden Lawrence
Published: February 2009

The pollination ecology, breeding system and population genetic structure of three climbingBauhiniaspeciesB. championii(4 populations, 23 individuals),B. corymbosa(2 populations, 25 individuals) andB. glauca(8 populations, 76 individuals) were studied in Hong Kong, southern China. We hypothesize that the climbingBauhiniaspecies will attract targeted pollinators to achieve out-cross success and high levels of self-incompatibility will be expected to maintain diversity, with local population expansion relying on vegetative propagation. All three species have inflorescences consisting of numerous small, pale, fragrant flowers, which show diurnal anthesis. Field observations revealed that all three species are predominantly pollinated by bees (particularlyApis mellifera) and butterflies (GraphiumandPapiliospecies), althoughB. championiiis also pollinated by wasps and flies.Bauhinia corymbosaandB. glaucahave sucrose-dominant nectar, whereasB. championiihas hexose-dominant nectar. In controlled-pollination experiments fruit and seed set were generally highest following artificial out-crossing. The index of self-incompatibility ofB. championiiis 1.07, indicating self-compatibility;B. corymbosaandB. glaucawere obligately self-incompatible. The population genetic structure and variation of theBauhiniaspecies was investigated using ISSR markers. Generally the three species have moderate within-population (meanHS= 0.206) and high among-population genetic variation (meanGST= 0.284). No correlation exists between the geographical and genetic distance, possibly due to the small local population size. All three species showed high levels of heterozygosity as expected for predominantly out-crossing long-lived K-selected species.
The impact in the UK of the Central and Eastern European HIV epidemics
Authors: DELPECH V. C. , YIN Z. , ABERNETHY J. , HILL C. , LOGAN L. , CHADBORN T. R. , RICE B. D.
Published: February 2009

Despite increasing migration, the impact of HIV epidemics from Central and Eastern Europe (C&EE) on the UK HIV epidemic remains small. C&EE-born adults comprised 1·2% of adults newly diagnosed with HIV in the UK between 2000 and 2007. Most C&EE-born women probably acquired their infection heterosexually in C&EE. In contrast, 59% of C&EE-born men reported sex with men, half of whom probably acquired their infection in the UK. Previously undiagnosed HIV prevalence in C&EE-born sexual-health-clinic attendees was low (2007, 0·5%) as was overall HIV prevalence in C&EE-born women giving birth in England (2007, <0·1%). The high proportion of men who have sex with men (MSM) suggests under-reporting of this group in C&EE HIV statistics and/or migration of MSM to the UK. In addition to reducing HIV transmission in injecting drug users, preventative efforts aimed at C&EE-born MSM both within their country of origin and the UK are required.
Three extensional models of type theory
Authors: VAN DEN BERG BENNO
Published: February 2009

We compare three categorical models of type theory with extensional constructs: setoids over extensional type theory; setoids over intensional type theory and a certain free exact category (the free ‘ΠW-pretopos’). By studying the amount of choice available in these categories, we are able show that they are distinct.
A Spectral Erdős–Stone–Bollobás Theorem
Authors: NIKIFOROV VLADIMIR
Published: February 2009

Let r ≥ 3 and (c/rr)r log n ≥ 1. If G is a graph of order n and its largest eigenvalue μ(G) satisfies

then G contains a complete r-partite subgraph with r − 1 parts of size ⌊(c/rr)r log n⌋ and one part of size greater than n1−cr−1.

This result implies the Erdős–Stone–Bollobás theorem, the essential quantitative form of the Erdős–Stone theorem. Another easy consequence is that if F1, F2, . . . are r-chromatic graphs satisfying v(Fn) = o(log n), then
Simplex Stability
Authors: MUBAYI DHRUV , RAMADURAI RESHMA
Published: February 2009

A d-simplex is a collection of d + 1 sets such that every d of them has non-empty intersection and the intersection of all of them is empty. Fix k ≥ d + 2 ≥ 3 and let be a family of k-element subsets of an n-element set that contains no d-simplex. We prove that if $|\cG| \geq (1 - o(1))\binom{n-1 }{k-1}$, then there is a vertex x of such that the number of sets in omitting x is o(nk−1) (here o(1)→ 0 and n → ∞). A similar result when n/k is bounded from above was recently proved in [10].

Our main result is actually stronger, and implies that if $|\cG| > (1 + \epsilon)\binom{n-1 }{ k-1}$ for any ϵ < 0 and n sufficiently large, then contains d + 2 sets A, A1, . . . ,Ad+1 such that the Ais form a d-simplex, and A contains an element of ∩j≠iAj for each i. This generalizes, in asymptotic form, a recent result of Vestraëte and the first author [18], who proved it for d = 1, ϵ = 0 and n ≥ 2k.
TYPE 1 DIABETES IN PREGNANCY; INFLUENCES ON MOTHER AND FETUS
Authors: NELSON SCOTT M , LINDSAY ROBERT S
Published: February 2009

Type 1 diabetes complicates around 1 in 200 to 300 pregnancies in the United Kingdom. Historically maternal type 1 diabetes carried very high risks for mother and child. Introduction of insulin led to an immediate, marked decline in the previously very high rates of maternal mortality; in contrast an improvement in perinatal outcomes occurred more slowly but was nevertheless dramatic. This is strikingly demonstrated by the temporal decline in perinatal mortality in offspring of mothers with type 1 diabetes which was virtually universal before use of insulin in the 1920's, likely remained in excess of 20% even in the 1960's and fell to under 4% by the 1990's. The reasons for this more gradual improvement in perinatal outcomes cannot be defined with precision but will have been influenced by improved glycaemic management with use of intensive, multiple dose insulin treatment and home glucose monitoring; improvements in obstetric and neonatal management, and better management of complications of diabetes before and during pregnancy. In 1989 the St Vincent declaration proposed that pregnancy outcomes in women with type 1 diabetes should approximate those of the non-diabetic population. While the long term improvements in fetal outcomes have been dramatic, contemporary surveys confirm a persistent doubling or more of rates of congenital anomaly and a three to four fold increase in perinatal mortality in the UK and other European countries which will require further clinical innovation to overcome.
Fibroblasts from the new-born male testicle of Guangxi Bama mini-pig (Sus scrofa) can support nuclear transferred embryo development in vitro
Authors: Liu Hong-Bo , Lv Pei-Ru , Yang Xiao-Gan , Qin Xiao-E , Pi Dao-Yuan , Lu Yang-Qing , Lu Ke-Huan , Lu Sheng-Sheng , Li Dong-sheng
Published: February 2009

Miniature pigs are valuable for research in xenotransplantation and as models for investigating human diseases. Although many mammalian species have been cloned, the success rates have been very low, especially in the pig. In the present study, an attempt was made to optimize somatic cell nuclear transfer (SCNT) protocols for use in the production of the Guangxi Bama mini-pig. Firstly, mini-pig fibroblast cells from a new-born Guangxi Bama piglet were isolated and cultured. Cell type was identified by fluorescence immunocytochemistry (ICC); the cells expressed cimentin, but not cytoceratin and follicular stimulation hormone receptor (FSHR). Secondly, the optimal cell cycle synchronization protocol for treating fibroblast cells from the newborn piglet's testicle was investigated by contact inhibition and serum starvation. When fibroblast cells were treated by contact inhibition, a higher fusion (66.0% vs. 58.3%, p > 0.05) and blastocyst production (20.8% vs. 15.1, p > 0.05) rates were obtained than with serum starvation. Thirdly, to examine the ability of old cells to be morphologically remodelled after activation, testicular fibroblasts (passage 10–14) were introduced into enucleated oocytes; enlarged nuclei were formed in most of the reconstructed embryos at 6 h and enlarged nuclei or distinct pseudopronuclei were formed in nearly all the reconstructed embryos at 12 h. The old donor cell could be morphologically remodelled correctly and was competent to support embryo development to the blastocyst in vitro. Fourthly, the in vitro development potential of the cloned embryos was investigated using two types of donor cell: ear fibroblasts and low or high passage testicular fibroblasts. The rate of fusion was highest using low passage testicle fibroblasts (84.5% vs. 69.8% and 80.0%, p < 0.05), as was development to the blastocyst stage (14.6% vs. 7.7% and 6.3%, p < 0.05). Finally, the effect of phytohaemagglutinin (PHA) on parthenogenetic and cloned embryo development was examined. The PHA had no significant effect on the parthenogenetic embryos, but cloned embryo development to the blastocyst stage was significantly increased by PHA (10μg/ml), (13.4% vs. 5.6% and 5.6%, p < 0.05).
Endovascular treatment of an occluded popliteal aneurysm with locoregional thrombolysis followed by stent graft exclusion
Authors: Leithäuser  , Park
Published: February 2009

Popliteal artery aneurysms can thrombose or cause distal embolization and are therefore potentially limb-threatening lesions. This report describes the case of a 70-year-old man with severe claudication due to a thrombosed aneurysm of the left popliteal artery. He gave consent for a locoregional thrombolytical therapy, but refused standard surgical treatment. Thus, we developed the idea to restore blood flow by means of thrombolysis first, and then to perform a definitive repair of the aneurysm after a period of time. After successful thrombolysis and after 14 days as an outpatient with weight adjusted subcutaneous heparin and daily exercise, the man was free of symptoms. An endovascular repair with a Hemobahn stentgraft was performed. At the end, the procedure was successfull. This stepwise endovascular approach can change an acute into an elective situation and positively influence long-term results.
Die Erfassung von Aufmerksamkeits- und Verhaltensproblemen im Unterricht mit dem Fragebogen zur Verhaltensbeurteilung im Unterricht (FVU)
Authors: Breuer Dieter , Rettig Klaus , Döpfner Manfred
Published: February 2009

Zusammenfassung. Sowohl für diagnostische Zwecke als auch für die Beurteilung von Interventionen in der psychotherapeutischen und der pädagogischen Praxis sowie in der Forschung sind Verfahren sehr wichtig, die im Lehrerurteil Störungen des Arbeitsverhaltens von Schülern im Unterricht zeitökonomisch und reliabel erfassen. Diese fehlen aber im deutschen Sprachraum. Daher wurde der Fragebogen zur Verhaltensbeurteilung im Unterricht (FVU) auf der Basis der englischsprachigen SKAMP-Skala entwickelt, die im Rahmen von Studien zu Aufmerksamkeitsdefizit-/Hyperaktivitätsstörungen (ADHS) eingesetzt wurde. In der vorliegenden Studie wurde der FVU in drei klinischen Stichproben im Umfang von n1 = 50, n2 = 28 und n3 = 79 Kindern und Jugendlichen hinsichtlich der Validität und Reliabilität untersucht. Anhand einer konfirmatorischen Faktorenanalyse erweisen sich die beiden Subskalen Aufmerksamkeitsprobleme und mangelnde Regelbefolgung nach Elimination eines Items als faktoriell valide. Die Interrater-Reliabilität ist eingeschränkt ausreichend, die interne Konsistenz und Test-Retest-Reliabilität sind zufriedenstellend. Auch hinsichtlich der konvergenten, divergenten und differenziellen Validitäten zeigen sich befriedigende Ergebnisse. Der FVU eignet sich für die Erfassung von Störungen des Arbeitsverhaltens von Schülern im Unterricht in zeitlich kurzen Abständen sowie zur sensiblen Erfassung von Verhaltensveränderungen. Weitere psychometrische Studien sowie Normierungsstudien an größeren Stichproben sind jedoch für den Einsatz des Fragebogens in der Routine notwendig.
Die Erfassung von Wahn und Halluzinationen in der Normalbevölkerung
Authors: Lincoln Tania M. , Keller Eva , Rief Winfried
Published: February 2009

Zusammenfassung. Die hohe Prävalenz wahnähnlicher Überzeugungen und halluzinatorischen Erlebens in der Bevölkerung erfordert spezifische Selbstbeurteilungsskalen, die diese subklinischen Phänomene abbilden. In der vorliegenden Untersuchung werden Reliabilität und Validität deutschsprachiger Adaptationen des Peters et al. Delusions Inventory ( Peters, Joseph & Garety, 1999b ) sowie der Launay-Slade Hallucination Scale ( Launay & Slade, 1981 ) an einer in Bezug auf Alter, Geschlecht und Bildungsstand annähernd repräsentativen Stichprobe aus der Normalbevölkerung (n = 359) und einer Stichprobe von Personen mit Schizophrenie (n = 54) untersucht. Beide Skalen weisen eine gute interne Konsistenz sowie hinreichende Kriteriums- und Konstruktvalidität auf. Trotz der Eignung der Skalen zur Differenzierung zwischen Personen mit und Personen ohne Schizophrenie zeigte sich, dass die Items zu wahnähnlichen Überzeugungen und halluzinatorischem Erleben auch in der Bevölkerungsstichprobe in relevanten Ausmaßen bejaht wurden. Weiterhin zeigte sich, dass halluzinatorische Erlebnisse und wahnähnliche Überzeugungen in der Bevölkerung mit erhöhtem psychischen Leidensdruck einhergehen.
Die Konstruktion eines optimalen eindimensionalen Tests mittels nichtparametrischer Testtheorie (NIRT) am Beispiel des MR SOC
Authors: Scheiblechner Hartmann , Lutz Rainer
Published: February 2009

Zusammenfassung. In diesem Beitrag werden zentrale Aspekte der nichtparametrischen Testtheorie (NIRT; Scheiblechner, 2007 ) am Beispiel eines Fragebogens zum Kohärenzsinn (MR SOC; Lutz, 2001 ) illustriert. Zuerst werden das Konstrukt des Kohärenzsinns und die Konstruktion des Fragebogens mittels Klassischer Testtheorie dargestellt. In den folgenden Kapiteln wird die Trennung in zwei Unterskalen (positiv und negativ) „blind” (d.h. ohne Kenntnis der Ergebnisse der klassischen Analyse und ohne Kenntnis des Iteminhalts) anhand der nichtparametrischen Testtheorie nachvollzogen. Die Ergebnisse stimmen hervorragend überein. Über die klassische Testtheorie hinaus bedeutet die Geltung des ISOP Modells den Nachweis einer homomorphen, d.h. strukturerhaltenden Abbildung der Strukturen in den Daten in die theoretischen Strukturen des Modells (Skalenwerte und deren Relationen). Die Eindimensionalität, die Geltung der Axiome der schwachen Unabhängigkeit, die spezifische Objektivität der geschätzten Parameter, die Optimalität der Parameterschätzungen und der scoring function (Auswertungsregeln) werden somit empirisch abgesichert. Die übliche Auswertungspraxis durch den Rohwert (die Summe der Einzelitem-Antworten) wird für diesen Test widerlegt, da die Wechselwirkungen zwischen Personenparameter bzw. Itemparameter und Antwortskala eine sinnvolle Aufsummierung der Antwortpunkte verhindern.
Analysis of electrical activity and seismicity in the natural time domain for the volcanic‐seismic swarm activity in 2000 in the Izu Island region, Japan
Authors: Uyeda S. , Kamogawa M. , Tanaka H.
Published: February 2009

Seismicity and geoelectric potential changes, possibly associated with the seismic swarm activity in 2000 in the Izu Island region, Japan, are analyzed in the framework of the natural time χ, which has been recently introduced as an index of the kth event χ = k/N, where N is the total number of events. The Izu 2000 swarm activity lasted for about 2 months with some 7000 shocks with magnitude M ≥ 3 and five M ≥ 6 shocks, and was preceded by a pronounced electrical activity with innumerable signals that started 2 months prior to the swarm onset. It is shown, first, that the seismicity subsequent to the electrical activity approaches to a critical stage a few days before the occurrence of the first M ≥ 6 shock and, second, that the electrical signals also have the properties characteristic to the critical stage. Despite the big differences in time scale and numbers of electric signals and earthquakes, these features are found similar to those in Greece. The present results suggest that both in Greece and Japan, the electrical activity as well as the subsequent seismicity may have a self‐similar structure and exhibits similar dynamic evolution toward critical stage.
Drift and mixing under the ocean surface revisited: Stratified conditions and model‐data comparisons
Authors: Rascle Nicolas , Ardhuin Fabrice
Published: February 2009

A one‐dimensional model of the ocean near‐surface currents is presented. It includes the enhanced near‐surface mixing due to the waves, the wave‐induced Stokes drift, the Stokes‐Coriolis (SC) effect, and the stratification. Near‐surface current shears from this model are compared with the shears of the quasi‐Eulerian currents measured using a wave‐following platform during the Shelf Mixed Layer Experiment (SMILE). It is shown that the downwind current shears observed during SMILE are well modeled. However, the observed crosswind shears are in poor agreement with the model. The Stokes‐Coriolis (SC) term could qualitatively explain this misfit, but it is one order of magnitude too weak. The Ekman‐Stokes spiral of the model is compared with the spiral observed during the long time series of measurements Long Term Upper Ocean Study 3. The effects of stratification are taken into account. The mean velocity profiles of the model closely agree with observations. However, there is no evidence of the SC effect on the shape of the observed current profile. The observed profile is found to be a consequence of the current rectification due to the time‐varying stratification. The SC effect calculated from a numerical wave hindcast is weak but should have been observed. In fact, it is estimated that the wave‐induced bias in the current measurements is larger than the SC effect. Finally, it is shown that the variation of surface drift with wave age, which was estimated to be small in unstratified conditions, is important in the presence of shallow mixed layers.
Shelfbreak frontal eddies over the continental slope north of Cape Hatteras
Authors: Churchill James H. , Gawarkiewicz Glen
Published: February 2009

Shelfbreak and slope eddies have been implicated as important agents in the exchange of water between the shelf and slope domains of the Middle Atlantic Bight (MAB). Here we present temperature, salinity, and velocity data from a series of shipboard transects that intercepted a rich eddy field over the slope of the southern MAB. Attention is focused on a well‐sampled cyclonic eddy, of roughly 60‐km diameter and 300‐m depth, that translated southward at 0.1 m s−1. The eddy was composed of a mix of water masses including MAB shelf and slope water, Gulf Stream water, and water from the MAB shelfbreak front. Gradient Richardson numbers suggest that these water masses were subject to vigorous turbulent vertical mixing. The transport of shelfbreak frontal water contained within the eddy was substantial. In the upper 100 m, shelfbreak frontal water comprised ∼75% of the eddy's volume. This frontal water fraction moved southward with a transport of ∼0.4 Sv, comparable with the volume transport within the shelfbreak frontal jet. A number of factors indicate that this highly energetic eddy, with maximum azimuthal velocity of 0.7 m s−1, was generated through instability of the shelfbreak frontal jet. The eddy had apparently developed rapidly (in <3 days), consistent with models of eddy generation through baroclinic instability of the shelfbreak frontal jet. The eddy's potential temperature/salinity (θ/S) properties and energy density closely matched the θ/S properties and energy density found in the frontal jet to the north of the eddy.
Early detection of ocean acidification effects on marine calcification
Authors: Ilyina Tatjana , Zeebe Richard E. , Maier‐Reimer Ernst , Heinze Christoph
Published: February 2009

Ocean acidification is likely to impact calcification rates in many pelagic organisms, which may in turn cause significant changes in marine ecosystem structure. We examine effects of changes in marine CaCO3 production on total alkalinity (TA) in the ocean using the global biogeochemical ocean model HAMOCC. We test a variety of future calcification scenarios because experimental studies with different organisms have revealed a wide range of calcification sensitivities to CaCO3 saturation state. The model integrations start at a preindustrial steady state in the year 1800 and run until the year 2300 forced with anthropogenic CO2 emissions. Calculated trends in TA are evaluated taking into account the natural variability in ocean carbonate chemistry, as derived from repeat hydrographic transects. We conclude that the data currently available does not allow discerning significant trends in TA due to changes in pelagic calcification caused by ocean acidification. Given different calcification scenarios, our model calculations indicate that the TA increase over time will start being detectable by the year 2040, increasing by 5–30 μmol kg−1 compared to the present‐day values. In a scenario of extreme reductions in calcification, large TA changes relative to preindustrial conditions would have occurred at present, which we consider very unlikely. However, the time interval of reliable TA observations is too short to disregard this scenario. The largest increase in surface ocean TA is predicted for the tropical and subtropical regions. In order to monitor and quantify possible early signs of acidification effects, we suggest to specifically target those regions during future ocean chemistry surveys.