bluuebunny/crossref_metadata_2025 huggingface dataset:
Apolipoprotein E genotypes modulate fibrosis progression in patients with chronic hepatitis C and persistently normal transaminases
Authors: Fabris Carlo , Vandelli Carmen , Toniutto Pierluigi , Minisini Rosalba , Colletta Cosimo , Falleti Edmondo , Smirne Carlo , Pirisi Mario
Published: June 2010

Background and Aim:  Carriage of the apolipoprotein E (Apo E) variants, E2, E3 and E4, affects cholesterol metabolism and may be involved in the persistence of hepatitis C virus (HCV) infection. Our aim was to verify whether carriage of specific Apo E variants modulates the course of hepatitis C.

Methods:  We studied a cohort of 116 HCV‐positive patients (49 male subjects) with persistently normal transaminases and an Ishak staging score ≤ 2 at an initial biopsy. These untreated patients underwent regular clinical monitoring (median histological follow up: 10 years). Apo E variants were genotyped and results were related to the histological outcome.

Results:  The mean ± standard deviation staging scores were 0.9 ± 0.7 at entry versus 1.9 ± 1.2 at the end of follow up, P < 0.0001. Initial and final staging scores in the E3/E3 homozygotes (n = 74) were 1.0 ± 0.7 versus 2.1 ± 1.3, P < 0.0001, while in the remaining patients (n = 42) they were 0.9 ± 0.6 versus 1.5 ± 1.0, P < 0.002. A synergistic effect was observed between Apo E polymorphisms and baseline serum cholesterol values: patients not carrying any E3 allele, as well as carriers of a single E3 allele with serum cholesterol concentration > 190 mg/dL were more likely to have a favorable outcome (final vs initial staging score increased in 7/66, did not change in 10/46, and decreased in 3/4, P < 0.005).

Conclusions:  Some of the variability in the natural history of patients with persistently normal transaminases with initially mild hepatitis C can be related to their Apo E genetic background.
N‐methyl‐4‐isoleucine cyclosporine attenuates CCl4‐induced liver fibrosis in rats by interacting with cyclophilin B and D
Authors: Wang Hui , Zhang Yuguo , Wang Tailing , You Hong , Jia Jidong
Published: June 2010

Background and Aim:  N‐methyl‐4‐isoleucine cyclosporine (NIM811), a new analogue of cyclosporine A, can inhibit collagen deposition in vitro and reduce liver necrosis in a bile‐duct‐ligation animal model. However, whether NIM811 effects on CCl4‐induced rat liver fibrosis, and the related mechanism has not been determined.

Methods:  A liver fibrosis model was induced in Wistar rats using CCl4 for 6 weeks. Meanwhile, two different doses of NIM811 (low‐dose 10 mg/kg and high‐dose 20 mg/kg) were given to the CCl4‐treated rats. Liver fibrosis was then evaluated according to histopathological scoring and liver hydroxyproline content. Serum alanine aminotransferase, aspartate aminotransferase and albumin levels, expression of matrix metalloproteinase‐13, tissue inhibitor of metalloproteinase‐1, α‐smooth muscle actin and cyclophilin B and D in liver tissue were determined. Cyclophilin B and D were also studied in an hepatic stellate cell line.

Results:  Hydroxyproline content was decreased in both NIM811 groups compared with the model (P < 0.05). Liver necrosis and fibrosis were also attenuated in the NIM811 groups. NIM811 suppressed the expression of tissue inhibitor of metalloproteinase‐1, transforming growth factor beta mRNA and α‐smooth muscle actin protein in liver tissue. Expression of cyclophilin B in the fibrosis model was increased compared with the normal group (P < 0.05), and was decreased significantly in the low‐dose NIM811 treatment group (P < 0.05), which indicated that cyclophilin B might have a profibrotic effect. In vitro studies revealed that cyclophilin B and/or D knockout were associated with collagen inhibition.

Conclusions:  NIM811 attenuates liver fibrosis in a CCl4‐induced rat liver fibrosis model, which may be related to binding with cyclophilin B and D.
Clinical trial: Inhibitory effect of revaprazan on gastric acid secretion in healthy male subjects
Authors: Kim Hyung‐Keun , Park Soo‐Heon , Cheung Dae‐Young , Cho Young‐Seok , Kim Jin‐Il , Kim Sung‐Soo , Chae Hiun‐Suk , Kim Jae‐Kwang , Chung In‐Sik
Published: June 2010

Background and Aim:  Revaprazan is a novel acid pump antagonist. The aim of this study was to investigate the inhibitory effect of revaprazan on gastric acid secretion in healthy male subjects.

Methods:  In a double‐blind, three‐way cross‐over study, 30 healthy male volunteers were randomized to 100, 150 or 200 mg of oral revaprazan daily for 7 days. Serum gastrin concentration was measured, and 24‐h intragastric pH was recorded at baseline and on days 1 and 7 of each administration period. Serial blood samples were processed for pharmacokinetics.

Results:  Median intragastric pH over 24 h and mean percentage time that pH was > 4 increased in a dose‐dependent manner and were significantly higher on days 1 and 7 compared with baseline in all groups (P < 0.05). The antisecretory effect of revaprazan was rapid and nearly maximal on day 1 in all groups. Serum gastrin levels were rapidly normalized by 100 and 150 mg/day of revaprazan on days 1 and 7, but were significantly higher in the 200 mg/day revaprazan group. The pharmacokinetic effect was rapidly absorbed and eliminated on days 1 and 7 in all groups.

Conclusions:  Revaprazan rapidly and effectively inhibits gastric acid secretion in healthy male subjects. Therefore, revaprazan can be used as an effective drug for acid‐related disease.
Early discharge from a neonatal intensive care unit and rates of readmission
Authors: Seki Kazuo , Iwasaki Shiho , An Hiromi , Horiguchi Haruko , Mori Masaaki , Nishimaki Shigeru , Yokota Shumpei
Published: June 2010

Background:  Increasing admissions to neonatal intensive care units (NICUs) demand early discharge from the units. Our hospital aims to early discharge patients who meet the following requirements: they are able to regulate body temperature; neither apnea nor bradycardia is observed; and bodyweight increases with lactation. We studied the real state of this strategy.

Methods:  We looked at postmenstrual age, bodyweight, complication at the time of discharge and the readmission rate in 609 patients with gestational age of less than 34 weeks, who were discharged from our NICU between January 2000 and March 2008.

Results:  The postmenstrual age and bodyweight at discharge decreased with the increase of gestational age. This tendency was stronger in cases with gestational age of less than 26 weeks. A comparison was made between two patient groups with a gestational age of less than 26 weeks and with the age of 26 weeks or longer. Many patients with a gestational age of less than 26 weeks suffered frequently from complications and were on home oxygen therapy. The readmission rates within 3 months and 1 year of NICU discharge were 10.4% and 26.9% in patients with gestational age between 22 and 25 weeks, respectively, while those rates were 2.8% and 7.4% in patients with gestational weeks of 26 to 34, respectively.

Conclusion:  The postmenstrual age and bodyweight at NICU discharge decreased in inverse proportion to gestational age, especially less than 26 weeks. Our requirements for early discharge were verified by the readmission rate in this investigation.
Prevalence and associations of blinding trachoma in indigenous Australians within central Australia: the Central Australian Ocular Health Study
Authors: Landers John , Henderson Tim , Craig Jamie
Published: June 2010

Abstract

Purpose:  To determine the prevalence and associations of blinding trachoma within the indigenous Australian population living in central Australia.

Methods:  A total of 1884 individuals aged 20 years or older, living among 30 remote communities within the statistical local area of ‘Central Australia’, were recruited for this study. This equated to 36% of those aged 20 years or older and 67% of those aged 40 years or older within this district. Participants were recruited as they presented to the eye clinic at each remote community. Anterior segment examination was performed and the rates of trachomatous trichiasis (TT) and trachomatous corneal opacification (CO) were documented. The prevalence of TT and CO in one or both eyes was presented.

Results:  There were 6.1% (95% CI 5.0–7.2) (8.3% of those aged 40 years or older) who had TT and 3.3% (95% CI 2.5–4.1) (4.4% of those aged 40 years or older) who had CO. Both TT and CO were associated with advancing age and female sex. Prevalence varied widely between communities, from 0% to 33% for TT and 0% to 27% for CO.

Conclusion:  Our study has shown that blinding trachoma remains endemic among indigenous Australians in central Australia. However, compared with previous estimates, the prevalence of TT and CO appears to be decreasing.
Improved anticoagulant control in patients using home international normalized ratio testing and decision support provided through the internet
Authors: Harper P. , Pollock D.
Published: June 2010

Aim: To compare anticoagulant control using self‐testing and decision support provided via the internet with standard laboratory testing.

Methods: A prospective comparative study of 41 patients on long‐term warfarin. All patients were monitored using a laboratory‐based service for at least 12 months prior to changing to self‐testing using a portable testing device and online decision support. The level of anticoagulant control was assessed using the time the international normalized ratio (INR) was within the therapeutic range (TTR), the proportion of INR results in range and the interval between tests. This was a non‐inferiority study.

Results: There was no statistically significant difference between the two methods of anticoagulant control with a trend in favour of self‐testing; the mean TTR was 72% vs 81%. However, a small cohort of patients with poor control (TTR 38%) during laboratory testing achieved a significant improvement (TTR 71%) using self‐testing. The INR was above the therapeutic range for a similar time in both groups but below the range for a significantly shorter period during self‐testing suggesting a lower risk of complication in this group.

Conclusion: Self‐testing with online computer decision support achieved anticoagulant control at least as good as laboratory management. Additional benefits of a home‐based service make this an attractive option for selected patients.
Immediate‐early gene response to repeated immobilization: Fos protein and arc mRNA levels appear to be less sensitive than c‐fos mRNA to adaptation
Authors: Ons Sheila , Rotllant David , Marín‐Blasco Ignacio J. , Armario Antonio
Published: June 2010

Stress exposure resulted in brain induction of immediate‐early genes (IEGs), considered as markers of neuronal activation. Upon repeated exposure to the same stressor, reduction of IEG response (adaptation) has been often observed, but there are important discrepancies in literature that may be in part related to the particular IEG and methodology used. We studied the differential pattern of adaptation of the IEGs c‐fos and arc (activity‐regulated cytoskeleton‐associated protein) after repeated exposure to a severe stressor: immobilization on wooden boards (IMO). Rats repeatedly exposed to IMO showed reduced c‐fos mRNA levels in response to acute IMO in most brain areas studied: the medial prefrontal cortex (mPFC), lateral septum (LS), medial amygdala (MeA), paraventricular nucleus of the hypothalamus (PVN) and locus coeruleus. In contrast, the number of neurons showing Fos‐like immunoreactivity was only reduced in the MeA and the various subregions of the PVN. IMO‐induced increases in arc gene expression were restricted to telencephalic regions and reduced by repeated IMO only in the mPFC. Double‐labelling in the LS of IMO‐exposed rats revealed that arc was expressed in only one‐third of Fos+ neurons, suggesting two populations of Fos+ neurons. These data suggest that c‐fos mRNA levels are more affected by repeated IMO than corresponding protein, and that arc gene expression does not reflect adaptation in most brain regions, which may be related to its constitutive expression. Therefore, the choice of a particular IEG and the method of measurement are important for proper interpretation of the impact of chronic repeated stress on brain activation.
Multi‐array silicon probes with integrated optical fibers: light‐assisted perturbation and recording of local neural circuits in the behaving animal
Authors: Royer Sébastien , Zemelman Boris V. , Barbic Mladen , Losonczy Attila , Buzsáki György , Magee Jeffrey C.
Published: June 2010

Recordings of large neuronal ensembles and neural stimulation of high spatial and temporal precision are important requisites for studying the real‐time dynamics of neural networks. Multiple‐shank silicon probes enable large‐scale monitoring of individual neurons. Optical stimulation of genetically targeted neurons expressing light‐sensitive channels or other fast (milliseconds) actuators offers the means for controlled perturbation of local circuits. Here we describe a method to equip the shanks of silicon probes with micron‐scale light guides for allowing the simultaneous use of the two approaches. We then show illustrative examples of how these compact hybrid electrodes can be used in probing local circuits in behaving rats and mice. A key advantage of these devices is the enhanced spatial precision of stimulation that is achieved by delivering light close to the recording sites of the probe. When paired with the expression of light‐sensitive actuators within genetically specified neuronal populations, these devices allow the relatively straightforward and interpretable manipulation of network activity.
Generation of interneuron diversity in the mouse cerebral cortex
Authors: Gelman Diego M. , Marín Oscar
Published: June 2010

Gamma‐aminobutyric acid‐containing (GABAergic) interneurons play an important role in the function of the cerebral cortex. Through mostly inhibitory mechanisms, interneurons control hyperexcitability, and synchronize and shape the spatiotemporal dynamics of cortical activity underlying various brain functions. Their influence on cortical function is remarkably diverse, a reflection of the large variety of interneuronal populations that exist in the mammalian cortex. Research over the past few years has rapidly transformed our understanding of their mechanisms underlying the generation of different classes of interneurons. In this review, we summarize recent progress on this process, progress which holds the promise of providing a rational framework for their classification, as well as means to understand their role in cortical processing.
Distinct synaptic properties of perisomatic inhibitory cell types and their different modulation by cholinergic receptor activation in the CA3 region of the mouse hippocampus
Authors: Szabó Gergely G. , Holderith Noémi , Gulyás Attila I. , Freund Tamás F. , Hájos Norbert
Published: June 2010

Perisomatic inhibition originates from three types of GABAergic interneurons in cortical structures, including parvalbumin‐containing fast‐spiking basket cells (FSBCs) and axo‐axonic cells (AACs), as well as cholecystokinin‐expressing regular‐spiking basket cells (RSBCs). These interneurons may have significant impact in various cognitive processes, and are subjects of cholinergic modulation. However, it is largely unknown how cholinergic receptor activation modulates the function of perisomatic inhibitory cells. Therefore, we performed paired recordings from anatomically identified perisomatic interneurons and pyramidal cells in the CA3 region of the mouse hippocampus. We determined the basic properties of unitary inhibitory postsynaptic currents (uIPSCs) and found that they differed among cell types, e.g. GABA released from axon endings of AACs evoked uIPSCs with the largest amplitude and with the longest decay measured at room temperature. RSBCs could also release GABA asynchronously, the magnitude of the release increasing with the discharge frequency of the presynaptic interneuron. Cholinergic receptor activation by carbachol significantly decreased the uIPSC amplitude in all three types of cell pairs, but to different extents. M2‐type muscarinic receptors were responsible for the reduction in uIPSC amplitudes in FSBC– and AAC–pyramidal cell pairs, while an antagonist of CB1 cannabinoid receptors recovered the suppression in RSBC–pyramidal cell pairs. In addition, carbachol suppressed or even eliminated the short‐term depression of uIPSCs in FSBC– and AAC–pyramidal cell pairs in a frequency‐dependent manner. These findings suggest that not only are the basic synaptic properties of perisomatic inhibitory cells distinct, but acetylcholine can differentially control the impact of perisomatic inhibition from different sources.
Testing for criticality in ecosystem dynamics: the case of Amazonian rainforest and savanna fire
Authors: Pueyo Salvador , De Alencastro Graça Paulo Maurício Lima , Barbosa Reinaldo Imbrozio , Cots Ricard , Cardona Eva , Fearnside Philip M.
Published: June 2010

Ecology Letters(2010) 13: 793–802

We test for two critical phenomena in Amazonian ecosystems: self‐organized criticality (SOC) and critical transitions. SOC is often presented in the complex systems literature as a general explanation for scale invariance in nature. In particular, this mechanism is claimed to underlie the macroscopic structure and dynamics of terrestrial ecosystems. These would be inextricably linked to the action of fire, which is conceived as an endogenous ecological process. We show that Amazonian savanna fires display the scale‐invariant features characteristic of SOC but do not display SOC. The same is true in Amazonian rainforests subject to moderate drought. These findings prove that there are other causes of scale invariance in ecosystems. In contrast, we do find evidence of a critical transition to a megafire regime under extreme drought in rainforests; this phenomenon is likely to determine the time scale of a possible loss of Amazonian rainforest caused by climate change.
Managing diabetes in cystic fibrosis
Authors: Laguna T. A. , Nathan B. M. , Moran A.
Published: June 2010

Cystic fibrosis related diabetes (CFRD) is the most common co‐morbidity in persons with cystic fibrosis (CF). As the life expectancy of persons with CF continues to increase, the need to proactively diagnose and aggressively treat CFRD and its potential complications has become more apparent. CFRD negatively impacts lung function, growth and mortality, making its diagnosis and management crucial in a population already at high risk for early mortality. Compared to type 1 and type 2 diabetes, CFRD is a unique entity, requiring a thorough understanding of its unique pathophysiology to facilitate the creation and utilization of an effective medical treatment plan. The physiology of CFRD is complex, likely consisting of a combination of insulin deficiency, insulin resistance and a genetic predisposition towards the development of diabetes. However, the hallmark of CFRD is insulin deficiency, necessitating the use of exogenous insulin as the mainstay of therapy. Insulin administration, in combination with a multidisciplinary team of health professionals with expertise in the care of patients with CF and CFRD, is the cornerstone of the care for these patients. The goals of treatment of the CFRD population are to reverse protein catabolism, maintain a healthy weight, and reduce acute and chronic diabetes complications. Creating a partnership between the treatment team and the patient is the ideal way to accomplish these goals and is essential for successful diabetes care.
Health sector recovery in early post‐conflict environments: experience from southern Sudan
Authors: Cometto Giorgio , Fritsche Gyuri , Sondorp Egbert
Published: June 2010

Health sector recovery in post‐conflict settings presents an opportunity for reform: analysis of policy processes can provide useful lessons.2 The case of southern Sudan is assessed through interviews, a literature review, and by drawing on the experience of former technical advisers to the Ministry of Health. In the immediate post‐conflict phase, the health system in southern Sudan was characterised by fragmentation, low coverage of health services, dismal health outcomes and limited government capacity. Health policy was extensively shaped by the interplay of context, actors and processes: the World Bank and the World Health Organization became the primary drivers of policy change. Lessons learned from the southern Sudan case include the need for: sustained investment in assessment and planning of recovery activities; building of procurement capacity early in the recovery process; support for funding instruments that can disburse resources rapidly; and streamlining the governance structures and procedures adopted by health recovery financing mechanisms and adapting them to the local context.
Individual preparedness and mitigation actions for a predicted earthquake in Istanbul
Authors: Tekeli‐Yeşil Sıdıka , Dedeoǧlu Necati , Tanner Marcel , Braun‐Fahrlaender Charlotte , Obrist Birgit
Published: June 2010

This study investigated the process of taking action to mitigate damage and prepare for an earthquake at the individual level. Its specific aim was to identify the factors that promote or inhibit individuals in this process. The study was conducted in Istanbul, Turkey—where an earthquake is expected soon—in May and June 2006 using qualitative methods. Within our conceptual framework, three different patterns emerged among the study subjects. Outcome expectancy, helplessness, a low socioeconomic level, a culture of negligence, a lack of trust, onset time/poor predictability, and normalisation bias inhibit individuals in this process, while location, direct personal experience, a higher education level, and social interaction promote them. Drawing on these findings, the paper details key points for better disaster communication, including whom to mobilise to reach target populations, such as individuals with direct earthquake experience and women.
Cyclone disaster vulnerability and response experiences in coastal Bangladesh
Authors: Alam Edris , Collins Andrew E.
Published: June 2010

For generations, cyclones and tidal surges have frequently devastated lives and property in coastal and island Bangladesh. This study explores vulnerability to cyclone hazards using first‐hand coping recollections from prior to, during and after these events. Qualitative field data suggest that, beyond extreme cyclone forces, localised vulnerability is defined in terms of response processes, infrastructure, socially uneven exposure, settlement development patterns, and livelihoods. Prior to cyclones, religious activities increase and people try to save food and valuable possessions. Those in dispersed settlements who fail to reach cyclone shelters take refuge in thatched‐roof houses and big‐branch trees. However, women and children are affected more despite the modification of traditional hierarchies during cyclone periods. Instinctive survival strategies and intra‐community cooperation improve coping post cyclone. This study recommends that disaster reduction programmes encourage cyclone mitigation while being aware of localised realities, endogenous risk analyses, and coping and adaptation of affected communities (as active survivors rather than helpless victims).
Emergency preparedness consultants at the local government level: the Israeli experience
Authors: Maor Moshe
Published: June 2010

This study evaluates the effectiveness of the Municipal Emergency Consultation project in eight Israeli local authorities. The initiative centres on the appointment of independent emergency preparedness consultants entrusted with tailoring an emergency preparedness package to suit the specific needs of each locality. Regarding emergency preparedness improvements, in all of the municipalities examined, a concept of municipal emergency operation was consolidated and the derived emergency plan tested. Emergency work processes were structured and service‐level agreements reached between municipality departments. Where necessary, a‐linear patterns of municipal functioning in an emergency were established. Concerning a ‘spillover’ of emergency preparedness improvements into routine operations, and a ‘spillover’ of routine management improvements into local emergency preparedness, two municipalities near Gaza, which typically function in an emergency routine, saw a significant ‘spillover’ of emergency preparedness into routine functioning. In other localities, local managers chose to improve a number of municipal structures and procedures in times of routine functioning, which are also related to the functioning of the municipality during an emergency.
Between war and peace: humanitarian assistance in violent urban settings
Authors: Lucchi Elena
Published: June 2010

Cities are fast becoming new territories of violence.1 The humanitarian consequences of many criminally violent urban settings are comparable to those of more traditional wars, yet despite the intensity of the needs, humanitarian aid to such settings is limited. The way in which humanitarian needs are typically defined, fails to address the problems of these contexts, the suffering they produce and the populations affected. Distinctions between formal armed conflicts, regulated by international humanitarian law, and other violent settings, as well as those between emergency and developmental assistance, can lead to the neglect of populations in distress. It can take a lot of time and effort to access vulnerable communities and implement programmes in urban settings, but experience shows that it is possible to provide humanitarian assistance with a significant focus on the direct and indirect health consequences of violence outside a traditional conflict setting. This paper considers the situation of Port‐au‐Prince (Haiti), Rio de Janeiro (Brazil) and Guatemala City (Guatemala).
Civilians under fire: evacuation behaviour in north Israel during the Second Lebanon War
Authors: Gidron David , Peleg Kobi , Jaffe Dena , Shenhar Gili
Published: June 2010

This paper seeks to understand evacuation behaviour in a case of spontaneous evacuation. During the Second Lebanon War of 2006, more than one‐third of residents in north Israel spontaneously evacuated—the remainder stayed in situ. Using a telephone survey of 665 respondents residing in north Israel, we were able to characterise the behaviour of evacuees and non‐evacuees. The main reasons cited for evacuating were fear of injury to self or family, the effect on children, inability to remain in a protective space, and family pressure. The main reasons cited for remaining at home were no suitable alternative, did not perceive a high level of danger, had to go to work, and there is no place like home. There were no significant differences with regard to most socio‐demographic characteristics of the population. These findings should aid emergency managers in preparing the population for a future emergency and in engaging in effective dialogue with the population during an emergency on the evacuation option.
Bureaucratic Performance and Control in British Politics: Asylum Policy 1994–2007
Authors: Jennings Will
Published: June 2010

There is a wealth of research into time series dynamics of bureaucratic control in the federal presidential system of the US, but no equivalent investigation in unitary parliamentary systems. This article proposes an approach for measurement of the effect of political interventions on bureaucratic outputs in British politics. It throws some light on tools of bureaucratic control that are associated with the fusion of legislative and executive powers in Britain's Westminster system. In contrast to the US, political control in the form of oversight or appointments is not required because government is able to intervene directly in bureaucratic activities through legislative, executive and administrative controls. It uses Box-Tiao time series models to analyse administration of the UK asylum system by the Immigration and Nationality Directorate of the Home Office.
Decoding the Signal Effects of Job Candidate Attraction to Corporate Social Practices
Authors: SORENSON SARAH , MATTINGLY JAMES E. , LEE FELISSA K.
Published: June 2010

This article seeks to go beyond the implied assumption from previous research that job candidate attraction to corporate social practices is equivalent across individuals. To this end, we propose a framework for categorizing individuals' attraction to different corporate social performance profiles. Our framework is grounded in relational models theory and Mitroff's model of managers' “ideal organizations.” An inductive approach was used to elaborate upon the model and assess the extent to which candidates preferences vary. Data were collected from prospective job seekers regarding their attraction to social practices that benefit or harm various stakeholders, and these responses were used to develop profiles of job candidates' attraction to distinct profiles of organizations' social practices. The results provide a guide for managers who wish to improve the likelihood that an organization's social practices reflect what is best about its culture.
User‐Controllable Color Transfer
Authors: An Xiaobo , Pellacini Fabio
Published: June 2010

This paper presents an image editing framework where users use reference images to indicate desired color edits. In our approach, users specify pairs of strokes to indicate corresponding regions in both the original and the reference image that should have the same color “style”. Within each stroke pair, a nonlinear constrained parametric transfer model is used to transfer the reference colors to the original. We estimate the model parameters by matching color distributions, under constraints that ensure no visual artifacts are present in the transfer result. To perform transfer on the whole image, we employ optimization methods to propagate the model parameters defined at each stroke location to spatially‐close regions of similar appearance. This stroke‐based formulation requires minimal user effort while retaining the high degree of user control necessary to allow artistic interpretations. We demonstrate our approach by performing color transfer on a number of image pairs varying in content and style, and show that our algorithm outperforms state‐of‐the‐art color transfer methods on both user‐controllability and visual qualities of the transfer results.
Contrast‐aware Halftoning
Authors: Li Hua , Mould David
Published: June 2010

This paper proposes two variants of a simple but efficient algorithm for structure‐preserving halftoning. Our algorithm extends Floyd‐Steinberg error diffusion; the goal of our extension is not only to produce good tone similarity but also to preserve structure and especially contrast, motivated by our intuition that human perception is sensitive to contrast. By enhancing contrast we attempt to preserve and enhance structure also.

Our basic algorithm employs an adaptive, contrast‐aware mask. To enhance contrast, darker pixels should be more likely to be chosen as black pixels while lighter pixels should be more likely to be set as white. Therefore, when the positive error is diffused to nearby pixels in a mask, the dark pixels absorb less error and the light pixels absorb more. Conversely, negative error is distributed preferentially to dark pixels. We also propose using a mask with values that drop off steeply from the centre, intended to promote good spatial distribution. It is a very fast method whose speed mainly depends on the size of the mask. But this method suffers from distracting patterns.

We then propose a variant on the basic idea which overcomes the first algorithm's shortcomings while maintaining its advantages through a priority‐aware scheme. Rather than proceeding in random or raster order, we sort the image first; each pixel is assigned a priority based on its up‐to‐date distance to black or to white, and pixels with extreme intensities are processed earlier. Since we use the same mask strategy as before, we promote good spatial distribution and high contrast.

We use tone similarity, structure similarity, and contrast similarity to validate our algorithm. Comparisons with recent structure‐aware algorithms show that our method gives better results without sacrificing speed.
Multi‐Scale Geometry Interpolation
Authors: Winkler T. , Drieseberg J. , Alexa M. , Hormann K.
Published: June 2010

Interpolating vertex positions among triangle meshes with identical vertex‐edge graphs is a fundamental part of many geometric modelling systems. Linear vertex interpolation is robust but fails to preserve local shape. Most recent approaches identify local affine transformations for parts of the mesh, model desired interpolations of the affine transformations, and then optimize vertex positions to conform with the desired transformations. However, the local interpolation of the rotational part is non‐trivial for more than two input configurations and ambiguous if the meshes are deformed significantly. We propose a solution to the vertex interpolation problem that starts from interpolating the local metric (edge lengths) and mean curvature (dihedral angles) and makes consistent choices of local affine transformations using shape matching applied to successively larger parts of the mesh. The local interpolation can be applied to any number of input vertex configurations and due to the hierarchical scheme for generating consolidated vertex positions, the approach is fast and can be applied to very large meshes.
Deformation Transfer to Multi‐Component Objects
Authors: Zhou Kun , Xu Weiwei , Tong Yiying , Desbrun Mathieu
Published: June 2010

We present a simple and effective algorithm to transfer deformation between surface meshes with multiple components. The algorithm automatically computes spatial relationships between components of the target object, builds correspondences between source and target, and finally transfers deformation of the source onto the target while preserving cohesion between the target's components. We demonstrate the versatility of our approach on various complex models.
Fast and Efficient Skinning of Animated Meshes
Authors: Kavan L. , Sloan P.‐P. , O'Sullivan C.
Published: June 2010

Skinning is a simple yet popular deformation technique combining compact storage with efficient hardware accelerated rendering. While skinned meshes (such as virtual characters) are traditionally created by artists, previous work proposes algorithms to construct skinning automatically from a given vertex animation. However, these methods typically perform well only for a certain class of input sequences and often require long pre‐processing times. We present an algorithm based on iterative coordinate descent optimization which handles arbitrary animations and produces more accurate approximations than previous techniques, while using only standard linear skinning without any modifications or extensions. To overcome the computational complexity associated with the iterative optimization, we work in a suitable linear subspace (obtained by quick approximate dimensionality reduction) and take advantage of the typically very sparse vertex weights. As a result, our method requires about one or two orders of magnitude less pre‐processing time than previous methods.
Interactive High‐Quality Visualization of Higher‐Order Finite Elements
Authors: Üffinger Markus , Frey Steffen , Ertl Thomas
Published: June 2010

Higher‐order finite element methods have emerged as an important discretization scheme for simulation. They are increasingly used in contemporary numerical solvers, generating a new class of data that must be analyzed by scientists and engineers. Currently available visualization tools for this type of data are either batch oriented or limited to certain cell types and polynomial degrees. Other approaches approximate higher‐order data by resampling resulting in trade‐offs in interactivity and quality. To overcome these limitations, we have developed a distributed visualization system which allows for interactive exploration of non‐conforming unstructured grids, resulting from space‐time discontinuous Galerkin simulations, in which each cell has its own higher‐order polynomial solution. Our system employs GPU‐based raycasting for direct volume rendering of complex grids which feature non‐convex, curvilinear cells with varying polynomial degree. Frequency‐based adaptive sampling accounts for the high variations along rays. For distribution across a GPU cluster, the initial object‐space partitioning is determined by cell characteristics like the polynomial degree and is adapted at runtime by a load balancing mechanism. The performance and utility of our system is evaluated for different aeroacoustic simulations involving the propagation of shock fronts.
Uncertain 2D Vector Field Topology
Authors: Otto Mathias , Germer Tobias , Hege Hans‐Christian , Theisel Holger
Published: June 2010

We introduce an approach to visualize stationary 2D vector fields with global uncertainty obtained by considering the transport of local uncertainty in the flow. For this, we extend the concept of vector field topology to uncertain vector fields by considering the vector field as a density distribution function. By generalizing the concepts of stream lines and critical points we obtain a number of density fields representing an uncertain topological segmentation. Their visualization as height surfaces gives insight into both the flow behavior and its uncertainty. We present a Monte Carlo approach where we integrate probabilistic particle paths, which lead to the segmentation of topological features. Moreover, we extend our algorithms to detect saddle points and present efficient implementations. Finally, we apply our technique to a number of real and synthetic test data sets.
Global Illumination Compensation for Spatially Augmented Reality
Authors: Sheng Yu , Yapo Theodore C. , Cutler Barbara
Published: June 2010

When projectors are used to display images on complex, non‐planar surface geometry, indirect illumination between the surfaces will disrupt the final appearance of this imagery, generally increasing brightness, decreasing contrast, and washing out colors. In this paper we predict through global illumination simulation this unintentional indirect component and solve for the optimal compensated projection imagery that will minimize the difference between the desired imagery and the actual total illumination in the resulting physical scene. Our method makes use of quadratic programming to minimize this error within the constraints of the physical system, namely, that negative light is physically impossible. We demonstrate our compensation optimization in both computer simulation and physical validation within a table‐top spatially augmented reality system. We present an application of these results for visualization of interior architectural illumination. To facilitate interactive modifications to the scene geometry and desired appearance, our system is accelerated with a CUDA implementation of the QP optimization method.
gProximity: Hierarchical GPU‐based Operations for Collision and Distance Queries
Authors: Lauterbach C. , Mo Q. , Manocha D.
Published: June 2010

We present novel parallel algorithms for collision detection and separation distance computation for rigid and deformable models that exploit the computational capabilities of many‐core GPUs. Our approach uses thread and data parallelism to perform fast hierarchy construction, updating, and traversal using tight‐fitting bounding volumes such as oriented bounding boxes (OBB) and rectangular swept spheres (RSS). We also describe efficient algorithms to compute a linear bounding volume hierarchy (LBVH) and update them using refitting methods. Moreover, we show that tight‐fitting bounding volume hierarchies offer improved performance on GPU‐like throughput architectures. We use our algorithms to perform discrete and continuous collision detection including self‐collisions, as well as separation distance computation between non‐overlapping models. In practice, our approach (gProximity) can perform these queries in a few milliseconds on a PC with NVIDIA GTX 285 card on models composed of tens or hundreds of thousands of triangles used in cloth simulation, surgical simulation, virtual prototyping and N‐body simulation. Moreover, we observe more than an order of magnitude performance improvement over prior GPU‐based algorithms.
Procedural Generation of Roads
Authors: Galin E. , Peytavie A. , Maréchal N. , Guérin E.
Published: June 2010

In this paper, we propose an automatic method for generating roads based on a weighted anisotropic shortest path algorithm. Given an input scene, we automatically create a path connecting an initial and a final point. The trajectory of the road minimizes a cost function that takes into account the different parameters of the scene including the slope of the terrain, natural obstacles such as rivers, lakes, mountains and forests. The road is generated by excavating the terrain along the path and instantiating generic parameterized models.
Continuum Traffic Simulation
Authors: Sewall J. , Wilkie D. , Merrell P. , Lin M. C.
Published: June 2010

We present a novel method for the synthesis and animation of realistic traffic flows on large‐scale road networks. Our technique is based on a continuum model of traffic flow we extend to correctly handle lane changes and merges, as well as traffic behaviors due to changes in speed limit. We demonstrate how our method can be applied to the animation of many vehicles in a large‐scale traffic network at interactive rates and show that our method can simulate believable traffic flows on publicly‐available, real‐world road data. We furthermore demonstrate the scalability of this technique on many‐core systems.
Puzzle‐like Collage
Authors: Goferman Stas , Tal Ayellet , Zelnik‐Manor Lihi
Published: June 2010

Collages have been a common form of artistic expression since their first appearance in China around 200 BC. Recently, with the advance of digital cameras and digital image editing tools, collages have gained popularity also as a summarization tool. This paper proposes an approach for automating collage construction, which is based on assembling regions of interest of arbitrary shape in a puzzle‐like manner. We show that this approach produces collages that are informative, compact, and eye‐pleasing. This is obtained by following artistic principles and assembling the extracted cutouts such that their shapes complete each other.
Optimizing Photo Composition
Authors: Liu Ligang , Chen Renjie , Wolf Lior , Cohen‐Or Daniel
Published: June 2010

Aesthetic images evoke an emotional response that transcends mere visual appreciation. In this work we develop a novel computational means for evaluating the composition aesthetics of a given image based on measuring several well‐grounded composition guidelines. A compound operator of crop‐and‐retarget is employed to change the relative position of salient regions in the image and thus to modify the composition aesthetics of the image. We propose an optimization method for automatically producing a maximally‐aesthetic version of the input image. We validate the performance of the method and show its effectiveness in a variety of experiments.
Mesh Decomposition with Cross‐Boundary Brushes
Authors: Zheng Youyi , Tai Chiew‐Lan
Published: June 2010

We present a new intuitive UI, which we callcross‐boundary brushes, for interactive mesh decomposition. The user roughly draws one or more strokes across a desired cut and our system automatically returns a best cut running through all the strokes. By the different natures of part components (i.e., semantic parts) and patch components (i.e., flatter surface patches) in general models, we design two corresponding brushes: part‐brush and patch‐brush. These two types of brushes share a common user interface, enabling easy switch between them. The part‐brush executes a cut along an isoline of a harmonic field driven by the user‐specified strokes. We show that the inherent smoothness of the harmonic field together with a carefully designed isoline selection scheme lead to segmentation results that are insensitive to noise, pose, tessellation and variation in user's strokes. Our patch‐brush uses a novel facet‐based surface metric that alleviates sensitivity to noise and fine details common in region‐growing algorithms. Extensive experimental results demonstrate that our cutting tools can produce user‐desired segmentations for a wide variety of models even with single strokes. We also show that our tools outperform the state‐of‐art interactive segmentation tools in terms of ease of use and segmentation quality.
Shared Sampling for Real‐Time Alpha Matting
Authors: Gastal Eduardo S. L. , Oliveira Manuel M.
Published: June 2010

Image matting aims at extracting foreground elements from an image by means of color and opacity (alpha) estimation. While a lot of progress has been made in recent years on improving the accuracy of matting techniques, one common problem persisted: the low speed of matte computation. We present the first real‐time matting technique for natural images and videos. Our technique is based on the observation that, for small neighborhoods, pixels tend to share similar attributes. Therefore, independently treating each pixel in the unknown regions of a trimap results in a lot of redundant work. We show how this computation can be significantly and safely reduced by means of a careful selection of pairs of background and foreground samples. Our technique achieves speedups of up to two orders of magnitude compared to previous ones, while producing high‐quality alpha mattes. The quality of our results has been verified through an independent benchmark. The speed of our technique enables, for the first time, real‐time alpha matting of videos, and has the potential to enable a new class of exciting applications.
Articulated Billboards for Video‐based Rendering
Authors: Germann Marcel , Hornung Alexander , Keiser Richard , Ziegler Remo , Würmlin Stephan , Gross Markus
Published: June 2010

We present a novel representation and rendering method for free‐viewpoint video of human characters based on multiple input video streams. The basic idea is to approximate the articulated 3D shape of the human body using a subdivision into textured billboards along the skeleton structure. Billboards are clustered to fans such that each skeleton bone contains one billboard per source camera. We call this representationarticulated billboards.

In the paper we describe a semi‐automatic, data‐driven algorithm to construct and render this representation, which robustly handles even challenging acquisition scenarios characterized by sparse camera positioning, inaccurate camera calibration, low video resolution, or occlusions in the scene. First, for each input view, a 2D pose estimation based on image silhouettes, motion capture data, and temporal video coherence is used to create a segmentation mask for each body part. Then, from the 2D poses and the segmentation, the actual articulated billboard model is constructed by a 3D joint optimization and compensation for camera calibration errors. The rendering method includes a novel way of blending the textural contributions of each billboard and features an adaptive seam correction to eliminate visible discontinuities between adjacent billboards textures.

Our articulated billboards do not only minimize ghosting artifacts known from conventional billboard rendering, but also alleviate restrictions to the setup and sensitivities to errors of more complex 3D representations and multiview reconstruction techniques. Our results demonstrate the flexibility and the robustness of our approach with high quality free‐viewpoint video generated from broadcast footage of challenging, uncontrolled environments.