bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiovascular risk assessment in children following kidney transplantation
Authors: Dégi Arianna , Kerti Andrea , Kis Éva , Cseprekál Orsolya , Tory Kálmán , Szabó Attila J. , Reusz George S.
Published: June 2012

Dégi A, Kerti A, Kis É, Cseprekál O, Tory K, Szabó AJ, Reusz GS. Cardiovascular risk assessment in children following kidney transplantation.

Abstract:  CV diseases are the leading cause of death among patients with ESRD. RTX decreases the CV risk; however, it still remains definitely higher than that of the general population. Large multicenter and longitudinal studies are difficult to perform and hard end‐points of CV events are usually missing among pediatric population. Thus, appropriate estimation of CV risk is of crucial importance to define the potential hazards and to evaluate the effect of treatments aimed to reduce the risk. A number of validated non‐invasive methods are available to assess the extent of CV damage in adults, such as calcification scores, cIMT, aPWV, 24‐h ABPM, AASI, and HRV; however, they need adaptation, standardization, and validation in pediatric studies. cIMT and PWV are the most promising methods, as pediatric normative values are already present. The up‐to‐date treatment of ESRD aims not only to save life, but to offer the patient a life expectancy approaching that of the healthy population and to ensure a reasonable quality of life.
Correlation and clinical utility of pp65 antigenemia and quantitative polymerase chain reaction assays for detection of cytomegalovirus in pediatric renal transplant patients
Authors: Rha Brian , Redden David , Benfield Mark , Lakeman Fred , Whitley Richard J. , Shimamura Masako
Published: June 2012

Rha B, Redden D, Benfield M, Lakeman F, Whitley RJ, Shimamura M. Correlation and clinical utility of pp65 antigenemia and quantitative polymerase chain reaction assays for detection of cytomegalovirus in pediatric renal transplant patients.

Abstract:  qPCR and pp65 antigenemia assays are used to monitor CMV infection in renal transplant recipients, but correlation of assays in a pediatric population has not been evaluated. Paired CMV real‐time qPCR and pp65 antigenemia tests from 882 blood samples collected from 115 pediatric renal transplant recipients were analyzed in this retrospective cohort study for the strength of association and clinical correlates. The assays correlated well in detecting infection (κ = 0.61). Higher qPCR values were demonstrated with increasing levels of antigenemia (p < 0.01). Discordant test results were associated with antiviral treatment (OR 4.33, p < 0.01) and low‐level viremia, with odds of concordance increasing at higher qPCR values (OR 3.67, p  <  0.01), and no discordance occurring above 8500 genomic equivalents/mL. Among discordant samples, neither test preceded the other in detecting initial infection or in returning to negative while on treatment. Only two cases of disease occurred during the two‐yr study period. With strong agreement in the detection of CMV infection, either qPCR or pp65 antigenemia assays can be used effectively for monitoring pediatric renal transplant patients for both detection and resolution of infection.
A Novel Combined Method of Osteosynthesis in Treatment of Tibial Fractures: A Comparative Study on Sheep with Application of Rod‐Through‐Plate Fixator and Bone Plating
Authors: Tralman G. , Andrianov V. , Arend A. , Männik P. , Kibur R. T. , Nõupuu K. , Uksov D. , Aunapuu M.
Published: June 2012

The study compares the efficiency of a new bone fixator combining periostal and intramedullary osteosynthesis to bone plating in treatment of tibial fractures in sheep. Experimental osteotomies were performed in the middle third of the left tibia. Animals were divided into two groups: in one group (four animals) combined osteosynthesis (rod‐through‐plate fixator, RTP fixator) was applied, and in the other group (three animals) bone plating was used. The experiments lasted for 10 weeks during which fracture union was followed by radiography, and the healing process was studied by blood serum markers reflecting bone turnover and by histological and immunohistochemical investigations. In the RTP fixator group, animals started to load body weight on the operated limbs the next day after the surgery, while in the bone plating group, this happened only on the seventh day. In the RTP fixator group, consolidation of fractures was also faster, as demonstrated by radiographical, histological, and immunohistochemical investigations and in part by blood serum markers for bone formation. It can be concluded that application of RTP fixation is more efficient than plate fixation in the treatment of experimental osteotomies of long bones in sheep.
Carbohydrates Accumulation and Remobilization in Wheat Plants as Influenced by Combined Waterlogging and Shading Stress During Grain Filling
Authors: Li H. , Cai J. , Jiang D. , Liu F. , Dai T. , Cao W.
Published: June 2012

Wheat plants were subjected to combined waterlogging and shading stress (WS) at 0–7, 8–15, 16–23 and 24–31 days after anthesis (DAA), respectively. Compared to the non‐stressed plants, WS significantly decreased the final grain yield. Grain number was dramatically lowered by WS imposed at 0–7 DAA but hardly affected by other WS treatments; while the thousand‐kernel‐weight was unaffected by WS imposed at 0–7 DAA and lowered by other WS treatments. Photosynthate accumulation in the stem was decreased by WS imposed at 0–7 and 8–15 DAA, but was unaffected by WS imposed at later stages. Grain‐filling rate was decreased, although the apparent remobilization of carbohydrate reserves from stem to grain was stimulated under WS. The carbohydrate reserves stored in the lower stem internodes were activated earlier and remobilized much more than those in the upper internodes; however, the proportion of the apparent remobilized reserves among the different stem internodes was consistent for all treatments. WS decreased contents of fructans, fructose and sucrose in the stem, which coincided with increased activity of fructan exohydrolase and decreased activities of sucrose‐1‐fructosyltransferase and fructan‐1‐fructosyltransferse. The results indicate that post‐anthesis WS stimulated carbohydrate reserves remobilization by modifying the activities of the fructans‐catalysing enzymes in the stem.
Establishment and characterization of Roberts syndrome and SC phocomelia model medaka (Oryzias latipes)
Authors: Morita Akihiro , Nakahira Kumiko , Hasegawa Taeko , Uchida Kaoru , Taniguchi Yoshihito , Takeda Shunichi , Toyoda Atsushi , Sakaki Yoshiyuki , Shimada Atsuko , Takeda Hiroyuki , Yanagihara Itaru
Published: June 2012

Roberts syndrome and SC phocomelia (RBS/SC) are genetic autosomal recessive syndromes caused by establishment of cohesion 1 homolog 2 (
ESCO

2) mutation. RBS/SC appear to have a variety of clinical features, even with the same mutation of the
ESCO2 gene. Here, we established and genetically characterized a medaka model of RBS/SC by reverse genetics. The RBS/SC model was screened from a mutant medaka library produced by the Targeting Induced Local Lesions in Genomes method. The medaka mutant carrying the homozygous mutation at R80S in the conserved region of ESCO2 exhibited clinical variety (i.e. developmental arrest with craniofacial and chromosomal abnormalities and embryonic lethality) as characterized in RBS/SC. Moreover, widespread apoptosis and downregulation of some gene expression, including notch1a, were detected in the R80S mutant. The R80S mutant is the animal model for RBS/SC and a valuable resource that provides the opportunity to extend knowledge of ESCO2. Downregulation of some gene expression in the R80S mutant is an important clue explaining non‐correlation between genotype and phenotype in RBS/SC.
Performance of prostate‐specific antigen mass in estimation of prostate volume in Japanese men with benign prostate hyperplasia
Authors: Masuda Hitoshi , Kawakami Satoru , Sakura Mizuaki , Fujii Yasuhisa , Koga Fumitaka , Saito Kazutaka , Numao Noboru , Yonese Junji , Fukui Iwao , Kihara Kazunori
Published: June 2012

Objectives:  Obese men with benign prostate hyperplasia might have lower serum prostate‐specific antigen because of hemodilution, resulting in underestimation of total prostate volume by serum prostate‐specific antigen. The aim of this study was to compare the performance of prostate‐specific antigen mass as the absolute amount of prostate‐specific antigen protein secreted into circulation with that of serum prostate‐specific antigen in the prediction of total prostate volume.

Methods:  A total of 1517 men with serum prostate‐specific antigen up to 10 ng/mL, including 1425 with biopsy‐proven benign prostate hyperplasia, were enrolled in this study. Height and weight were used to estimate body mass index, body surface area and plasma volume. Prostate‐specific antigen mass was calculated as serum prostate‐specific antigen multiplied by plasma volume. The association between serum prostate‐specific antigen or prostate‐specific antigen mass and transrectal ultrasound‐measured total prostate volume were evaluated by Pearson's correlation coefficient (Υ), linear regression analyses and receiver operating characteristic curves.

Results:  Serum prostate‐specific antigen had an inverse relationship with plasma volume, decreasing as plasma volume increased, after adjustment of total prostate volume. Larger total prostate volume per serum prostate‐specific antigen was found in men with higher body mass index or plasma volume. Among all participants, the correlation (Υ = 0.456) between prostate‐specific antigen mass and total prostate volume was apparently stronger than that (Υ = 0.442) between serum prostate‐specific antigen and total prostate volume. Prostate‐specific antigen mass outperformed serum prostate‐specific antigen at estimating total prostate volume cut‐off values of 30 and 40 mL. These findings were more significant in men aged ≥60 years.

Conclusions:  Prostate‐specific antigen mass performs better than serum prostate‐specific antigen in estimating TPV, especially in men aged ≥60 years.
Effect of intermittent theta‐burst stimulation on akinesia and sensorimotor integration in patients with Parkinson’s disease
Authors: Degardin Adrian , Devos David , Defebvre Luc , Destée Alain , Plomhause Lucie , Derambure Philippe , Devanne Hervé
Published: June 2012

High‐frequency (HF) repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex (M1) has been shown to reduce akinesia in Parkinson’s disease (PD). Given that the processing of sensory afferents is deficient in PD and might be involved in akinesia, we sought to determine whether or not the application of very HF rTMS [intermittent theta‐burst stimulation (iTBS) protocol] over the M1 affected sensorimotor integration (SMI) and akinesia. The experiments were carried out in: (i) 11 patients taking their usual dopaminergic treatment (‘on‐drug’); (ii) eight of the latter patients after withdrawal of dopaminergic treatment (‘off‐drug’); and (iii) 10 de novo (drug‐naive) patients. Sham stimulation was applied in 11 other patients in the ‘on‐drug’ condition. SMI was investigated by conditioning a supra‐threshold transcranial magnetic stimulation pulse in the motor region controlling the abductor pollicis brevis with a nerve shock over the median nerve at time intervals corresponding to short‐ and long‐latency afferent inhibition (SAI and LAI) and afferent‐induced facilitation (AIF). Akinesia was assessed with a pointing test. In on‐drug, off‐drug and de novo patients, akinesia in the contralateral arm was lower after iTBS. Sham stimulation had no effect. In on‐drug patients (but not other groups), SMI was also influenced by iTBS, with an increase in AIF. No changes in SAI and LAI were observed. Our data suggest that iTBS might improve both akinesia and sensory processing in patients with PD taking levodopa.
Experience‐dependent brain plasticity after stroke: effect of ibuprofen and poststroke delay
Authors: Jablonka Jan A. , Kossut Malgorzata , Witte Otto W. , Liguz‐Lecznar Monika
Published: June 2012

Despite indications that brain plasticity may be enhanced after stroke, we have described impairment of experience‐dependent plasticity in rat cerebral cortex neighboring the stroke‐induced lesion. Photothrombotic stroke was centered behind the barrel cortex in one cerebral hemisphere of rats. Plasticity of cortical representation of one row of vibrissae was induced by sensory deprivation of all surrounding whiskers for 1 month, and visualized with [14C]‐2‐deoxyglucose autoradiography. In control rats deprivation resulted in an enlargement of functional cortical representation of the spared row of vibrissae. After a focal stroke neighbouring the barrel cortex, no plasticity of the spared row representation was found. Investigation of plastic changes with deprivation initiated 1 week and 1 month after stroke have shown that later poststroke onset of deprivation resulted in a partial recovery of cortical plasticity in the barrel field. Western blot analysis of proinflammatory enzyme cyclooxygenase‐2 (COX‐2) expression revealed its strong upregulation in the barrel cortex 24 h after stroke. When chronic treatment with the anti‐inflammatory drug ibuprofen (10 mg/kg or 20 mg/kg) accompanied deprivation, plasticity was restored. Ibuprofen applied before the ischemia also prevented the poststroke upregulation of COX‐2. The results strongly suggest that poststroke impairment of experience‐dependent cortical plasticity is caused by stroke‐induced inflammatory reactions that subside with poststroke delay and can be at least partially ameliorated by pharmacological treatment.
Cellular and subcellular localization of CXCL12 and CXCR4 in rat nociceptive structures: physiological relevance
Authors: Reaux‐Le Goazigo Annabelle , Rivat Cyril , Kitabgi Patrick , Pohl Michel , Melik Parsadaniantz Stéphane
Published: June 2012

Initial studies implicated the chemokine CXC motif ligand 12 (CXCL12) and its cognate CXC motif receptor 4 (CXCR4) in pain modulation. However, there has been no description of the distribution, transport and axonal sorting of CXCL12 and CXCR4 in rat nociceptive structures, and their direct participation in nociception modulation has not been demonstrated. Here, we report that acute intrathecal administration of CXCL12 induced mechanical hypersensitivity in naive rats. This effect was prevented by a CXCR4‐neutralizing antibody. To determine the morphological basis of this behavioural response, we used light and electron microscopic immunohistochemistry to map CXCL12‐ and CXCR4‐immunoreactive elements in dorsal root ganglia, lumbar spinal cord, sciatic nerve and skin. Light microscopy analysis revealed CXCL12 and CXCR4 immunoreactivity in calcitonin gene related peptide‐containing peptidergic primary sensory neurons, which were both conveyed to central and peripheral sensory nerve terminals. Electron microscopy clearly demonstrated CXCL12 and CXCR4 immunoreactivity in primary sensory nerve terminals in the dorsal horn; both were sorted into small clear vesicles and large dense‐core vesicles. This suggests that CXCL12 and CXCR4 are trafficked from nerve cell bodies to the dorsal horn. Double immunogold labelling for CXCL12 and calcitonin gene related peptide revealed partial vesicular colocalization in axonal terminals. We report, for the first time, that CXCR4 receptors are mainly located on the neuronal plasma membrane, where they are present at pre‐synaptic and post‐synaptic sites of central terminals. Receptor inactivation experiments, behavioural studies and morphological analyses provide strong evidence that the CXCL12/CXCR4 system is involved in modulation of nociceptive signalling.
Eight questions about invasions and ecosystem functioning
Authors: Strayer David L.
Published: June 2012

I pose eight questions central to understanding how biological invasions affect ecosystems, assess progress towards answering those questions and suggest ways in which progress might be made. The questions concern the frequency with which invasions affect ecosystems; the circumstances under which ecosystem change is most likely; the functions that are most often affected by invaders; the relationships between changes to ecosystems, communities, and populations; the long‐term responses of ecosystems to invasions; interactions between biological invasions and other anthropogenic activities and the difficulty of managing undesirable impacts of non‐native species. Some questions have been answered satisfactorily, others require more data and thought, and others might benefit from being reformulated or abandoned. Actions that might speed progress include careful development of trait‐based approaches; strategic collection and publication of new data, including more frequent publication of negative results; replacement of expert opinion with hard data where needed; careful consideration of whether questions really need to be answered, especially in cases where answers are being provided for managers and policy‐makers; explicit attention to and testing of the domains of theories; integrating invasions better into an ecosystem context; and remembering that our predictive ability is limited and will remain so for the foreseeable future.
Prevalence of depression among young people with Type 1 diabetes: a systematic review
Authors: Johnson B. , Eiser C. , Young V. , Brierley S. , Heller S.
Published: June 2012

Diabet. Med. 30, 199–208 (2013)

Aims  To determine: (1) prevalence of depression among young people with Type 1 diabetes compared with control groups or population norms; (2) implications of depression for HbA1c level; and (3) the relationship between history of depressive symptoms and future depressive symptoms.

Background  Among adults with Type 1 diabetes depression is higher than the general population, and has been associated with adverse implications for self‐care and HbA1c level. The last published review of depression among young people with Type 1 diabetes only included studies up to 1999.

Method  Systematic searches were conducted for articles published from January 1999 to December 2011 including young people (up to 25 years old) with Type 1 diabetes.

Results  Twenty‐three articles met the inclusion criteria. Of five studies that reported prevalence of depression compared with control groups, three found no differences. Of the three studies that investigated prevalence of depression making reference to population norms, all three showed higher rates of depressive symptoms. Fourteen of 15 studies found associations between more depressive symptoms and higher HbA1c level either cross‐sectionally or longitudinally. Past depressive symptoms were associated with later depressive symptoms.

Conclusions  Current evidence is inconclusive about whether there is increased prevalence of depression among young adults with Type 1 diabetes, as established among adults, but those who are more depressed have higher HbA1c level. This review is limited by methodological problems and no identified work in the UK met the inclusion criteria. Given the adverse clinical outcomes, we conclude there is a case for routine mental health screening for young adults with Type 1 diabetes.
Beyond Bergmann's rule: size–latitude relationships in marine Bivalvia world‐wide
Authors: Berke Sarah K. , Jablonski David , Krug Andrew Z. , Roy Kaustuv , Tomasovych Adam
Published: June 2012

Aim  Variations in body size are well established for many taxa of endotherms and ectotherms, but remain poorly documented for marine invertebrates. Here we explore how body size varies with latitude, temperature and productivity for a major marine invertebrate class, the Bivalvia.

Location  Continental shelves world‐wide.

Methods  We used regression models to assess univariate relationships between size and latitude as well as multivariate relationships between size, latitude and environmental parameters (mean and seasonality in temperature and mean productivity). The dataset consisted of 4845 species in 59 families from shelf depths at all latitudes in the Pacific and Atlantic oceans. We also used Blomberg's K to assess whether size–latitude relationships show phylogenetic signal, and test whether functional groups based on feeding mode, substrate relationships, mobility and fixation can account for observed size–latitude trends.

Results  Size–latitude trends are taxonomically and geographically common in bivalves, but vary widely in sign and strength – no simple explanations based on environmental parameters, phylogeny or functional group hold across all families. Perhaps most importantly, we found that the observed trends vary considerably between hemispheres and among coastlines.

Main conclusions  Broadly generalizable macroecological patterns in inter‐specific body size may not exist for marine invertebrates. Although size–latitude trends occur in many bivalve lineages, the underlying mechanisms evidently differ among regions and/or lineages. Fully understanding macroecological patterns requires truly global datasets as well as information about the evolutionary history of specific lineages and regions.
Taxonomic and geographic influences on fish otolith microchemistry
Authors: Chang Mei‐Yu , Geffen Audrey J
Published: June 2012

Fish otoliths are comprised primarily of CaCO3 and grow throughout an individual's lifetime. The chemical composition of otoliths is often a distinctive characteristic of the populations that live in discrete areas, and as a result, it has been used for population classification studies, supporting ecological and fisheries research. However, the deposition of chemical elements in the otolith is influenced by both physiological and environmental factors. We review observed trends in otolith elemental composition and then test the taxonomic and geographical patterns, using marine species in European waters. anova comparisons and multivariate analyses revealed strong taxonomic signals in species inhabiting the same region. Variations in Sr, Mg, Mn and Ba concentrations were most often species specific; for example, multivariate analyses showed separation of cod (Gadus morhua) and herring (Clupea harengus) based primarily on Mg and Sr concentrations, while Mn and Ba concentrations separated bluemouth (Helicolenus dactylopterus) and sole (Solea solea). The relative contributions of taxonomic and regional factors varied between elements. For cod and herring, for example, species‐specific differences explain 75% of the variation for Mn, but only 50% of the variation in Sr. Although there are significant regional differences within a single species on both a restricted and extensive geographic scale, these regional patterns are not the same for each species. As the amount of otolith composition data increases, representing more species and regions, as well as longer time series, further analyses can provide a deeper insight into the predictability of using otolith data in fisheries ecology.
Stochastic Progressive Photon Mapping for Dynamic Scenes
Authors: Weiss Maayan , Grosch Thorsten
Published: June 2012

Stochastic Progressive Photon Mapping (SPPM) is a method to simulate consistent global illumination. It is especially useful for complicated light paths like caustics seen through a glass surface. Up to now, SPPM can only be applied to a static scene and noise‐free images require hours to compute. Our approach is to extend this method to dynamic scenes (DSPPM) for an efficient simulation of animated objects and materials. We identify both hit point and photon information that can be re‐used for the pixel statistics of multiple frames. In comparison to an SPPM simulation performed for each frame, we achieve a 1.96 −9.53 speedup in our test scenes without changing correctness or simulation quality.
Real‐time Rendering of Dynamic Scenes under All‐frequency Lighting using Integral Spherical Gaussian
Authors: Iwasaki Kei , Furuya Wataru , Dobashi Yoshinori , Nishita Tomoyuki
Published: June 2012

We propose an efficient rendering method for dynamic scenes under all‐frequency environmental lighting. To render the surfaces of objects illuminated by distant environmental lighting, the triple product of the lighting, the visibility function and the BRDF is integrated at each shading point on the surfaces. Our method represents the environmental lighting and the BRDF with a linear combination of spherical Gaussians, replacing the integral of the triple product with the sum of the integrals of spherical Gaussians over the visible region of the hemisphere. We propose a new form of spherical Gaussian, the integral spherical Gaussian, that enables the fast and accurate integration of spherical Gaussians with various sharpness over the visible region on the hemisphere. The integral spherical Gaussian simplifies the integration to a sum of four pre‐integrated values, which are easily evaluated on‐the‐fly. With a combination of a set of spheres to approximate object geometries and the integral spherical Gaussian, our method can render object surfaces very efficiently. Our GPU implementation demonstrates realtime rendering of dynamic scenes with dynamic viewpoints, lighting, and BRDFs.
A Computational Model of Afterimages
Authors: Ritschel Tobias , Eisemann Elmar
Published: June 2012

Afterimages are optical illusions, particularly well perceived when fixating an image for an extended period of time and then looking at a neutral background, where an inverted copy of the original stimulus appears. The full mechanism that produces the perceived specific colors and shapes is complex and not entirely understood, but most of the important attributes can be well explained by bleaching of retinal photoreceptors (retinal kinetics). We propose a model to compute afterimages that allows us to simulate their temporal, color and time‐frequency behavior. Using this model, high dynamic range (HDR) content can be processed to add realistic afterimages to low dynamic range (LDR) media. Hereby, our approach helps in conveying the original source's luminance and contrast. It can be applied in real‐time on full‐HD HDR content using standard graphics hardware. Finally, our approach is validated in a perceptual study.
Unsharp Masking, Countershading and Halos: Enhancements or Artifacts?
Authors: Trentacoste Matthew , Mantiuk Ratal , Heidrich Wolfgang , Dufrot Florian
Published: June 2012

Countershading is a common technique for local image contrast manipulations, and is widely used both in automatic settings, such as image sharpening and tonemapping, as well as under artistic control, such as in paintings and interactive image processing software. Unfortunately, countershading is a double‐edged sword: while correctly chosen parameters for a given viewing condition can significantly improve the image sharpness or trick the human visual system into perceiving a higher contrast than physically present in an image, wrong parameters, or different viewing conditions can result in objectionable halo artifacts. In this paper we investigate the perception of countershading in the context of a novel mask‐based contrast enhancement algorithm and analyze the circumstances under which the resulting profiles turn from image enhancement to artifact for a range of parameters and viewing conditions. Our experimental results can be modeled as a function of the width of the countershading profile. We employ this empirical function in a range of applications such as image resizing, view dependent tone mapping, and countershading analysis in photographs and works of fine art.
Crowd Light: Evaluating the Perceived Fidelity of Illuminated Dynamic Scenes
Authors: Jarabo Adrian , Eyck Tom Van , Sundstedt Veronica , Bala Kavita , Gutierrez Diego , O'Sullivan Carol
Published: June 2012

Rendering realistic illumination effects for complex animated scenes with many dynamic objects or characters is computationally expensive. Yet, it is not obvious how important such accurate lighting is for the overall perceived realism in these scenes. In this paper, we present a methodology to evaluate the perceived fidelity of illumination in scenes with dynamic aggregates, such as crowds, and explore several factors which may affect this perception. We focus in particular on evaluating how a popular spherical harmonics lighting method can be used to approximate realistic lighting of crowds. We conduct a series of psychophysical experiments to explore how a simple approach to approximating global illumination, using interpolation in the temporal domain, affects the perceived fidelity of dynamic scenes with high geometric, motion, and illumination complexity. We show that the complexity of the geometry and temporal properties of the crowd entities, the motion of the aggregate as a whole, the type of interpolation (i.e., of the direct and/or indirect illumination coefficients), and the presence or absence of colour all affect perceived fidelity. We show that high (i.e., above 75%) levels of perceived scene fidelity can be maintained while interpolating indirect illumination for intervals of up to 30 frames, resulting in a greater than three‐fold rendering speed‐up.
A Simple Algorithm for Maximal Poisson‐Disk Sampling in High Dimensions
Authors: Ebeida Mohamed S. , Mitchell Scott A. , Patney Anjul , Davidson Andrew A. , Owens John D.
Published: June 2012

We provide a simple algorithm and data structures for d‐dimensional unbiased maximal Poisson‐disk sampling. We use an order of magnitude less memory and time than the alternatives. Our results become more favorable as the dimension increases. This allows us to produce bigger samplings. Domains may be non‐convex with holes. The generated point cloud is maximal up to round‐off error. The serial algorithm is provably bias‐free. For an output sampling of size n in fixed dimension d, we use a linear memory budget and empirical θ(n) runtime. No known methods scale well with dimension, due to the “curse of dimensionality.” The serial algorithm is practical in dimensions up to 5, and has been demonstrated in 6d. We have efficient GPU implementations in 2d and 3d. The algorithm proceeds through a finite sequence of uniform grids. The grids guide the dart throwing and track the remaining disk‐free area. The top‐level grid provides an efficient way to test if a candidate dart is disk‐free. Our uniform grids are like quadtrees, except we delay splits and refine all leaves at once. Since the quadtree is flat it can be represented using very little memory: we just need the indices of the active leaves and a global level. Also it is very simple to sample from leaves with uniform probability.
Computational Design of Rubber Balloons
Authors: Skouras Mélina , Thomaszewski Bernhard , Bickel Bernd , Gross Markus
Published: June 2012

This paper presents an automatic process for fabrication‐oriented design of custom‐shaped rubber balloons. We cast computational balloon design as an inverse problem: given a target shape, we compute an optimal balloon that, when inflated, approximates the target as closely as possible. To solve this problem numerically, we propose a novel physics‐driven shape optimization method, which combines physical simulation of inflatable elastic membranes with a dedicated constrained optimization algorithm. We validate our approach by fabricating balloons designed with our method and comparing their inflated shapes to the results predicted by simulation. An extensive set of manufactured sample balloons demonstrates the shape diversity that can be achieved by our method.
ON THE LOWER ARBITRAGE BOUND OF AMERICAN CONTINGENT CLAIMS
Authors: Acciaio Beatrice , Svindland Gregor
Published: June 2012

We prove that in a discrete‐time market model the lower arbitrage bound of an American contingent claim is itself an arbitrage‐free price if and only if it corresponds to the price of the claim optimally exercised under some equivalent martingale measure.
A METHOD FOR PRICING AMERICAN OPTIONS USING SEMI‐INFINITE LINEAR PROGRAMMING
Authors: Christensen Sören
Published: June 2012

We introduce a new approach for the numerical pricing of American options. The main idea is to choose a finite number of suitable excessive functions (randomly) and to find the smallest majorant of the gain function in the span of these functions. The resulting problem is a linear semi‐infinite programming problem, that can be solved using standard algorithms. This leads to good upper bounds for the original problem. For our algorithms no discretization of space and time and no simulation is necessary. Furthermore it is applicable even for high‐dimensional problems. The algorithm provides an approximation of the value not only for one starting point, but for the complete value function on the continuation set, so that the optimal exercise region and, for example, the Greeks can be calculated. We apply the algorithm to (one‐ and) multidimensional diffusions and show it to be fast and accurate.
DYNAMIC COHERENT ACCEPTABILITY INDICES AND THEIR APPLICATIONS TO FINANCE
Authors: Bielecki Tomasz R. , Cialenco Igor , Zhang Zhao
Published: June 2012

In this paper, we present a theoretical framework for studying coherent acceptability indices (CAIs) in a dynamic setup. We study dynamic CAIs (DCAIs) and dynamic coherent risk measures (DCRMs), and we establish a duality between them. We derive a representation theorem for DCRMs in terms of a so‐called dynamically consistent sequence of sets of probability measures. Based on these results, we give a specific construction of DCAIs. We also provide examples of DCAIs, both abstract and also some that generalize selected classical financial measures of portfolio performance.
LIQUIDATION IN LIMIT ORDER BOOKS WITH CONTROLLED INTENSITY
Authors: Bayraktar Erhan , Ludkovski Michael
Published: June 2012

We consider a framework for solving optimal liquidation problems in limit order books. In particular, order arrivals are modeled as a point process whose intensity depends on the liquidation price. We set up a stochastic control problem in which the goal is to maximize the expected revenue from liquidating the entire position held. We solve this optimal liquidation problem for power‐law and exponential‐decay order book models explicitly and discuss several extensions. We also consider the continuous selling (or fluid) limit when the trading units are ever smaller and the intensity is ever larger. This limit provides an analytical approximation to the value function and the optimal solution. Using techniques from viscosity solutions we show that the discrete state problem and its optimal solution converge to the corresponding quantities in the continuous selling limit uniformly on compacts.
Private Equity Lemons?Evidence on Value Creation in Secondary Buyouts
Authors: Achleitner Ann‐Kristin , Figge Christian
Published: June 2012

This paper analyses whether secondary buyouts have a value creation profile and offer equity returns different from those of primary buyouts. Using a sample of 2,456 buyout transactions (including 448 secondary buyouts), we find no evidence that secondary buyouts generate lower equity returns or offer fundamentally lower operational value creation potential. However, we can show that secondary buyouts obtain 28–30% more leverage than primary buyouts, even after controlling for debt market conditions. Furthermore, we find evidence that secondary buyouts are 6–9% more expensive than other buyouts.
Influence of an autochthonous starter culture and a commercial starter on the characteristics of Tenerife pasteurised goats’ milk cheese
Authors: GONZÁLEZ LORENA , ZÁRATE VICTORIA
Published: June 2012

Two batches of Tenerife cheese were produced from pasteurised goats’ milk, one with a commercial starter and another with an autochthonous starter consisting of three selected strains of lactic acid bacteria isolated from artisanal Tenerife cheese. Influence of starter on the characteristics of the cheeses was evaluated. Owing to the composition of the starters, lactobacilli and leuconostocs varied significantly between both cheeses. However, the type of starter did not significantly affect the physicochemical and proteolytic properties of the cheeses. In general, cheeses made with autochthonous starter received higher scores for sensory attributes, especially for aroma, than those made with commercial starter.
Developing the capacity of teacher‐librarians to meet the diverse needs of all schoolchildren: Project ENABLE
Authors: Myhill William N. , Hill Renee Franklin , Link Kristen , Small Ruth V. , Bunch Kelly
Published: June 2012

US school libraries are required to ensure that schoolchildren and school staff with disabilities have equal opportunity to use and benefit from library facilities and information services under federal law. However, evidence indicates teacher‐librarians (TLs) often lack the training, knowledge and skills to provide programmes and services that meet the needs of students with disabilities. Project ENABLE (Expanding Nondiscriminatory Access by Librarians Everywhere) was created to respond to this shortfall by designing, implementing and evaluating a professional development programme in New York State. The project applies a social model of disability to help 100 TLs, special educators and general educators further develop their skills and resources by teaming together to create an inclusive environment for all students. This is achieved through the use of universal design principles, appropriate assistive and other technologies, an emphasis on person‐first language and sensitivity simulations, a focus on inclusive lesson planning, and by developing collaboration capacity among participant teams. Curriculum development, data collection and analyses are presented. The effect of the Project ENABLE trainings was significant in terms of higher levels of skill and knowledge reported by participants for creating accessible library programmes, advancing inclusive education and building effective collaborations. Drawing from their workshop learning and resources, participant teams developed action plans to implement during the 2011–2012 school year. This project underscores the importance of TLs in the education of all students, including those with disabilities. Higher education and local professional development programmes must place greater emphasis on preparing TLs to perform this role effectively and confidently.
‘Unconscious’ inclusion of students with learning disabilities in a Malaysian mainstream primary school: teachers' perspectives
Authors: Lee Lay Wah , Low Hui Min
Published: June 2012

The inclusion of children with special needs in mainstream regular schools has been seen as the best practice in special education provision, most markedly since the 90s. International research has provided amassing evidence towards the advantages of inclusive model over a segregation model of special education provision. However, nearly two decades after the signing of the international pledge, namely the Salamanca Statement (UNESCO) towards accepting inclusive education, Malaysia has not yet fully gained the momentum to implement inclusive education for children with special needs, especially for children identified within the category of learning disabilities. Because of the delay in policy implementation, inclusive education remains sparingly practiced in some schools without formal support. This study aims to investigate a scenario of this practice in a mainstream primary school via interviewing the regular teachers. The ultimate aim of this investigation is to identify ways to move forward from the current practice of ‘unconscious inclusion’.
Students with special needs and 1:1 computing: a teacher's perspective
Authors: Corn Jenifer , Tagsold Jennifer T. , Argueta Rodolfo
Published: June 2012

To better understand the growing trend of 1:1 learning, researchers conducted an evaluation of a laptop initiative in 18 North Carolina high schools. The goal of the study was to provide information about the value of the initiative to enhance student learning, as well as to identify challenges to the successful implementation of 1:1 programs, strategies for meeting those challenges, and services and supports needed to enable successful programs throughout the state. This paper focuses on ways in which the initiative enhanced the learning experiences of students with disabilities in areas such as communication, reading ability, assessment, organisation and confidence. Data sources include teacher, student and administrator focus groups, which enable scholars to gain an array of insight regarding technology initiatives and students with special needs. Implications for educators and administrators are discussed.
The effect of rock composition on cyanobacterial weathering of crystalline basalt and rhyolite
Authors: Olsson‐Francis K. , Simpson A. E. , Wolff‐Boenisch D. , Cockell C. S.
Published: June 2012

The weathering of volcanic rocks contributes significantly to the global silicate weathering budget, effecting carbon dioxide drawdown and long‐term climate control. The rate of chemical weathering is influenced by the composition of the rock. Rock‐dwelling micro‐organisms are known to play a role in changing the rate of weathering reactions; however, the influence of rock composition on bio‐weathering is unknown. Cyanobacteria are known to be a ubiquitous surface taxon in volcanic rocks. In this study, we used a selection of fast and slow growing cyanobacterial species to compare microbial‐mediated weathering of bulk crystalline rocks of basaltic and rhyolitic composition, under batch conditions. Cyanobacterial growth caused an increase in the pH of the medium and an acceleration of rock dissolution compared to the abiotic controls. For example,
Anabaena cylindrica increased the linear release rate () of Ca, Mg, Si and K from the basalt by more than fivefold (5.21–12.48) and increased the pH of the medium by 1.9 units. Although A. cylindrica enhanced rhyolite weathering, the increase in was less than threefold (2.04–2.97) and the pH increase was only 0.83 units. The values obtained with
A. cylindrica were at least ninefold greater with the basalt than the rhyolite, whereas in the abiotic controls, the difference was less than fivefold. Factors accounting for the slower rate of rhyolite weathering and lower biomass achieved are likely to include the higher content of quartz, which has a low rate of weathering and lower concentrations of bio‐essential elements, such as, Ca, Fe and Mg, which are known to be important in controlling cyanobacterial growth. We show that at conditions where weathering is favoured, biota can enhance the difference between low and high Si‐rock weathering. Our data show that cyanobacteria can play a significant role in enhancing rock weathering and likely have done since they evolved on the early Earth.
Antidepressant‐like effect of bis‐eugenol in the mice forced swimming test: evidence for the involvement of the monoaminergic system
Authors: do Amaral Jeferson Falcão , Silva Maria Izabel Gomes , de Aquino Neto Manuel Rufino , Moura Brinell Arcanjo , de Carvalho Alyne Mara Rodrigues , Vasconcelos Patrícia Freire , Barbosa Filho José Maria , Gutierrez Stanley Juan Chavez , Vasconcelos Silvânia Maria Mendes , Macêdo Danielle Silveira , de Sousa Francisca Cléa Florenço
Published: June 2012

Dehydrodieugenol, known as bis‐eugenol, is a eugenol ortho dimer, and both compounds were able to exhibit anti‐inflammatory and antioxidant activities in previous studies. Furthermore, eugenol showed antidepressant‐like effect; however, the biological actions of bis‐eugenol on experimental models for screening antidepressant activity are still unknown. The present study investigated a possible antidepressant‐like activity of bis‐eugenol in the forced swimming test (FST) and tail suspension test (TST) in mice and the involvement in the monoaminergic system in this effect. In addition, a neurochemical analysis on brain monoamines of mice acutely treated with bis‐eugenol was also conducted. Bis‐eugenol decreased the immobility time in the FST and TST without accompanying changes in ambulation in the open field test at 10 mg/kg, i.p.. Nevertheless, it induced ambulation at 25 and 50 mg/kg doses. The anti‐immobility effect of bis‐eugenol (10 and 50 mg/kg, i.p.) was prevented by pretreatment of mice with p‐chlorophenylalanine (PCPA, 100 mg/kg, i.p., an inhibitor of serotonin synthesis, for four consecutive days), yohimbine (1 mg/kg, i.p., an α2‐adrenoceptor antagonist), SCH23390 (15 μg/kg, s.c., a dopamine D1 receptor antagonist) and sulpiride (50 mg/kg, i.p., a dopamine D2 receptor antagonist). Monoamines analysis using high‐performance liquid chromatograph revealed significant increase in the 5‐HT, NE and DA levels in brain striatum. The present study indicates that bis‐eugenol possesses antidepressant‐like activity in FST and TST by altering dopaminergic, serotonergic and noradrenergic systems function.
Assessment of changes in cardiac autonomic tone resulting from inflammatory response to the influenza vaccination
Authors: Perring S. , Jones E.
Published: June 2012

A total of 71 healthy volunteers opting to have a routine influenza vaccination were investigated for potential changes in cardiovascular autonomic tone resulting from the temporary inflammatory effects of an influenza vaccination. A number of temporal and frequency domain parameters of heart rate and breathing were assessed 2–5 days prior to vaccination and 1–4 days postvaccination. Three lead electrocardiograph (ECG), beat‐to‐beat finger blood pressure and chest plethysmography signals were measured. After an extended resting period, patients performed metronome‐guided breathing at six breaths per min for a period of 2 min. Standard Ewing tests of autonomic function were also performed. All volunteers completed a vaccine symptom questionnaire. A subgroup of 15 volunteers who reported significant symptomatic reaction to the vaccination for at least 24 h following vaccination were identified based on the results of the questionnaire. A significant reduction in measures of heart rate variability (HRV) obtained during metronome‐guided breathing was noted following vaccination in the subgroup of 15 symptomatic volunteers. No significant changes were observed in standard Ewing assessment, fractal dimension analysis, baroreflex sensitivity assessment or resting HRV. There was no evidence of significant reduction in autonomic tone following vaccination in the full sample of 71 volunteers. Results suggest a significant change in HRV response to a small inflammatory provocation and suggest further investigation of the inflammatory causes of dysautonomia is of value.
Phosphorus sorption and desorption properties of soils developed on basic rocks under a subhumid Mediterranean climate
Authors: Horta C. , Monteiro F. , Madeira M. , Torrent J.
Published: June 2012

Representative samples of A, B and C horizons from 11 pedons (Luvisols, Solonetzs and Cambisols) developed on intermediate and basic rocks were studied regarding evaluation of phosphorus (P) behaviour, with the aim of delineating site‐specific management practices. For this purpose, (i) sorption properties were evaluated by Langmuir and Freundlich isotherms, (ii) soil samples were fertilized to a level of ca. 0.5 mg P/L, estimated by the Freundlich isotherm fitted to each horizon and (iii) the amount of phosphate‐P desorbed to a dilute electrolyte mimicking fresh water over periods of up to 60 days at soil:solution ratios of 1:100, 1:1000 and 1:10 000 was measured. The pedons had a slightly acidic or alkaline reaction and a limited capacity to sorb P, sorption seemingly occurring by both adsorption and precipitation. The nature of the sorption processes seemed to change with depth: precipitation dominated in C horizons, adsorption in A horizons and both types of processes being balanced in B horizons. The short‐term capacity of the soil to transfer P to water was related to the sorption curve parameters and the nature of the process seemingly controlling sorption. The ability of soil to desorb P increased with decreasing soil:solution ratio and when precipitation was the dominant process in sorption. After P fertilizer application, soils exhibited a high capacity to transfer P to water, thus making it advisable to use a replacement P strategy to prevent P accumulation in the topsoil and its downward movement.