bluuebunny/crossref_metadata_2025 huggingface dataset:
Adenosine regulation of the immune response initiated by ischemia reperfusion injury
Authors: Boros D , Thompson J , Larson DF
Published: May 2015

It is clinically established that adenosine has negative chronotropic, antiarrhythmic effects and reduces arterial blood pressure. Adenosine addition to cardioplegic solutions used in cardiac operations is clinically well tolerated and has been shown to improve myocardial protection in several studies. However, the mechanism of action remains unclear. Therefore, it is important to define the effect of adenosine on the inflammatory cascade as immune cell activation occurs early during ischemia reperfusion injury. Adenosine appears to mediate the initial steps of the inflammatory cascade via its four G-coupled protein receptors: A1, A2A, A2B, and A3, expressed on neutrophils, lymphocytes and macrophages. The adenosine receptor isotype dictates the immune response. More specifically, the A1 and A3 receptors stimulate a pro-inflammatory immune response whereas the A2A and A2B are immunosuppressive. As the adenosine receptors are important for cardiac pre-conditioning and post-conditioning, adenosine may regulate the inflammatory responses initiated during ischemia-mediated immune injury related to myocardial protection.
An Approach to Assess Generalizability in Comparative Effectiveness Research
Authors: Steventon Adam , Grieve Richard , Bardsley Martin
Published: May 2015

Background. Policy makers require estimates of comparative effectiveness that apply to the population of interest, but there has been little research on quantitative approaches to assess and extend the generalizability of randomized controlled trial (RCT)–based evaluations. We illustrate an approach using observational data. Methods. Our example is the Whole Systems Demonstrator (WSD) trial, in which 3230 adults with chronic conditions were assigned to receive telehealth or usual care. First, we used novel placebo tests to assess whether outcomes were similar between the RCT control group and a matched subset of nonparticipants who received usual care. We matched on 65 baseline variables obtained from the electronic medical record. Second, we conducted sensitivity analysis to consider whether the estimates of treatment effectiveness were robust to alternative assumptions about whether “usual care” is defined by the RCT control group or nonparticipants. Thus, we provided alternative estimates of comparative effectiveness by contrasting the outcomes of the RCT telehealth group and matched nonparticipants. Results. For some endpoints, such as the number of outpatient attendances, the placebo tests passed, and the effectiveness estimates were robust to the choice of comparison group. However, for other endpoints, such as emergency admissions, the placebo tests failed and the estimates of treatment effect differed markedly according to whether telehealth patients were compared with RCT controls or matched nonparticipants. Conclusions. The proposed placebo tests indicate those cases when estimates from RCTs do not generalize to routine clinical practice and motivate complementary estimates of comparative effectiveness that use observational data. Future RCTs are recommended to incorporate these placebo tests and the accompanying sensitivity analyses to enhance their relevance to policy making.
Model-free detection and tracking of dynamic objects with 2D lidar
Authors: Wang Dominic Zeng , Posner Ingmar , Newman Paul
Published: May 2015

We present a new approach to detection and tracking of moving objects with a 2D laser scanner for autonomous driving applications. Objects are modelled with a set of rigidly attached sample points along their boundaries whose positions are initialized with and updated by raw laser measurements, thus allowing a non-parametric representation that is capable of representing objects independent of their classes and shapes. Detection and tracking of such object models are handled in a theoretically principled manner as a Bayes filter where the motion states and shape information of all objects are represented as a part of a joint state which includes in addition the pose of the sensor and geometry of the static part of the world. We derive the prediction and observation models for the evolution of the joint state, and describe how the knowledge of the static local background helps in identifying dynamic objects from static ones in a principled and straightforward way. Dealing with raw laser points poses a significant challenge to data association. We propose a hierarchical approach, and present a new variant of the well-known Joint Compatibility Branch and Bound algorithm to respect and take advantage of the constraints of the problem introduced through correlations between observations. Finally, we calibrate the system systematically on real world data containing 7,500 labelled object examples and validate on 6,000 test cases. We demonstrate its performance over an existing industry standard targeted at the same problem domain as well as a classical approach to model-free object tracking.
Fast marching tree: A fast marching sampling-based method for optimal motion planning in many dimensions
Authors: Janson Lucas , Schmerling Edward , Clark Ashley , Pavone Marco
Published: May 2015

In this paper we present a novel probabilistic sampling-based motion planning algorithm called the Fast Marching Tree algorithm (FMT*). The algorithm is specifically aimed at solving complex motion planning problems in high-dimensional configuration spaces. This algorithm is proven to be asymptotically optimal and is shown to converge to an optimal solution faster than its state-of-the-art counterparts, chiefly PRM* and RRT*. The FMT* algorithm performs a ‘lazy’ dynamic programming recursion on a predetermined number of probabilistically drawn samples to grow a tree of paths, which moves steadily outward in cost-to-arrive space. As such, this algorithm combines features of both single-query algorithms (chiefly RRT) and multiple-query algorithms (chiefly PRM), and is reminiscent of the Fast Marching Method for the solution of Eikonal equations. As a departure from previous analysis approaches that are based on the notion of almost sure convergence, the FMT* algorithm is analyzed under the notion of convergence in probability: the extra mathematical flexibility of this approach allows for convergence rate bounds—the first in the field of optimal sampling-based motion planning. Specifically, for a certain selection of tuning parameters and configuration spaces, we obtain a convergence rate bound of order O( n−1/ d+ ρ), where n is the number of sampled points, d is the dimension of the configuration space, and ρ is an arbitrarily small constant. We go on to demonstrate asymptotic optimality for a number of variations on FMT*, namely when the configuration space is sampled non-uniformly, when the cost is not arc length, and when connections are made based on the number of nearest neighbors instead of a fixed connection radius. Numerical experiments over a range of dimensions and obstacle configurations confirm our theoretical and heuristic arguments by showing that FMT*, for a given execution time, returns substantially better solutions than either PRM* or RRT*, especially in high-dimensional configuration spaces and in scenarios where collision-checking is expensive.
Towards versatile legged robots through active impedance control
Authors: Semini Claudio , Barasuol Victor , Boaventura Thiago , Frigerio Marco , Focchi Michele , Caldwell Darwin G. , Buchli Jonas
Published: May 2015

Robots with legs and arms have the potential to support humans in dangerous, dull or dirty tasks. A major motivation behind research on such robots is their potential versatility. However, these robots come at a high price in mechanical and control complexity. Hence, until they can demonstrate a clear advantage over their simpler counterparts, robots with arms and legs will not fulfill their true potential. In this paper, we discuss the opportunities for versatile robots that arise by actively controlling the mechanical impedance of joints and particularly legs. In contrast to passive elements such as springs, active impedance is achieved by torque-controlled joints allowing real-time adjustment of stiffness and damping. Adjustable stiffness and damping in real-time is a fundamental building block towards versatility. Experiments with our 80 kg hydraulic quadruped robot HyQ demonstrate that active impedance alone (i.e. no springs in the structure) can successfully emulate passively compliant elements during highly dynamic locomotion tasks (running, jumping and hopping); and that no springs are needed to protect the actuation system. Here we present results of a flying trot, also referred to as a running trot. To the best of the authors’ knowledge this is the first time a flying trot has been successfully implemented on a robot without passive elements such as springs. A critical discussion on the pros and cons of active impedance concludes the paper. This article is an extension of our previous work presented at the International Symposium on Robotics Research (ISRR) 2013.
Design, development, and evaluation of an MRI-guided SMA spring-actuated neurosurgical robot
Authors: Ho Mingyen , Kim Yeongjin , Cheng Shing Shin , Gullapalli Rao , Desai Jaydev P.
Published: May 2015

In this paper, we present our work on the development of a magnetic resonance imaging (MRI)-compatible minimally invasive neurosurgical intracranial robot (MINIR) comprising shape memory alloy (SMA) spring actuators and tendon–sheath mechanisms. We present the detailed modeling and analysis along with experimental results of the characterization of SMA spring actuators. Furthermore, to demonstrate image-feedback control, we used the images obtained from a camera to control the motion of the robot so that eventually continuous MR images could be used in the future to control robot motion. Since the image tracking algorithm may fail in some situations, we also developed a temperature feedback control scheme which served as a backup controller for the robot. Experimental results demonstrated that both image feedback and temperature feedback can be used to control the motion of MINIR. A series of MRI compatibility tests was performed on the robot and the experimental results demonstrated that the robot is MRI-compatible and no significant visual image distortion was observed in the MR images during robot operation.
Trading twitter: Amateur recorders and economies of scientific exchange at the Cornell Library of Natural Sounds
Authors: Bruyninckx Joeri
Published: May 2015

Scientists have long engaged in collaborations with field collectors, but how are such collaborations established and maintained? This article examines structures of collaborative data collection between professional scientists and various field recorders around the Cornell Library of Natural Sounds. The Library collects animal sound recordings for use in education, preservation, and entertainment, but primarily in the scientific field of bio-acoustics. Since 1945, the Library has enlisted academic researchers, commercial recorders and broadcasters (such as the British Broadcasting Corporation), and amateur sound hunters in its expansion. I argue that the Cornell Library of Natural Sounds managed to craft and sustain a crucial network of contributors through creative and strategic brokering with its collection of recordings/data. Drawing on notions from exchange theory, I show that sound recordings were valued not just as scientific data, but also as copyrighted commodities that could be bought, sold, traded, and converted in a range of economic, social, and symbolic capitals within collaborators’ respective social fields. Thus, aligning collaborators’ interests, these exchange relations enabled the Cornell Library of Natural Sounds to negotiate amateur recorders’ reliability, willingness to share work, and commitment to scientific standards, as well as the bonds that solidified their collaboration with the Cornell Library of Natural Sounds. Attending to the micro-economics of data exchange, this article thus brings into perspective the multi-dimensional processes through which data-flows are managed.
The business of the Anthropocene? Substantivist and diverse economies perspectives on SME engagement in local low carbon transitions
Authors: North Peter
Published: May 2015

The involvement of private sector actors in low carbon urban transitions is a neglected element of geographical analysis. Drawing on Polanyian, cultural economic geographies and the non-capitalocentric ethics of JK Gibson-Graham’s diverse economies perspective, the paper engages with the wider literature on the engagement of small and medium enterprises (SMEs) in environmental action, corporate social responsibility and low carbon transitions to develop a substantivist account of the contribution of SMEs to local low carbon transitions. The paper argues that, contra formalist economic analyses of economic rationality, SME owners should not be thought of as uncritical profit maximizers but as actors in favour of positive low carbon futures. Thus the paper argues that Polanyian economic geographies and diverse economies perspectives, which rarely speak to each other, can be drawn together, and concludes with suggestions for future research.
Boxing daze – using state-and-transition models to explore the evolution of socio-biophysical landscapes
Authors: Van Dyke Chris
Published: May 2015

Critical physical geography (CPG) proposes to bridge the lingering gap between human and physical geographers. To rejuvenate conversations among different corners of the discipline about the possibility of trans-disciplinary collaboration, CPG must provide unique epistemological, methodological, and conceptual frameworks that human and physical geographers alike will find appealing, relevant, and timely. These should help them perceptively characterize, narrate, and anticipate changes in socio-biophysical landscapes. This paper outlines a conceptual framework that can be harnessed in future CPG studies and reflects on what it means to be a critical geographer. To solve the epistemological dilemmas confronting CPG, this paper demonstrates that state-and-transition models (STMs) can provide a unifying framework to address questions about socio-biophysical landscape evolution. Originally developed to account for nonlinear dynamics in rangeland ecosystems, STMs have been used to analyze a variety of ecological, geomorphic, and hydrological transitions in complex biophysical landscapes. STMs have epistemological commonalities with explanatory frameworks pioneered by political ecologists, and while thus far they have been used to account for complex biophysical dynamics, they can be expanded to accommodate critical investigations of the social dynamics underpinning landscape change. By foregrounding the transitional dynamics of socio-biophysical landscape – a theme that has interested physical and critical human geographers – STMs establish a conceptual space in which to holistically interpret the interacting drivers that underwrite socio-biophysical landscape change.
International Classification of Headache Disorders 3rd edition beta-based field testing of vestibular migraine in China: Demographic, clinical characteristics, audiometric findings and diagnosis statues
Authors: Zhang Yixin , Kong Qingtao , Chen Jinjin , Li Lunxi , Wang Dayan , Zhou Jiying
Published: May 2015

Objectives

This study explored the clinical characteristics of vestibular migraine in Chinese subjects and performed a field test of the criteria of the International Classification of Headache Disorders 3rd edition beta version.

Methods

Consecutive patients with vestibular migraine were surveyed and registered in a headache clinic during the study period. The diagnosis of vestibular migraine was made according to International Classification of Headache Disorders 3rd edition beta version. Assessments included standardized neuro-otology bedside examination, pure-tone audiogram, bithermal caloric testing, neurological imaging, cervical X-ray or magnetic resonance imaging, Doppler ultrasound of cerebral arteries and laboratory tests.

Results

A total of 67 patients (62 female/five male, 47.8 ± 10.3 years old) were enrolled in this study. The mean ages of migraine and vertigo onset were 32.2 ± 11.5 and 37.9 ± 10.1 years, respectively. The most common migraine subtype was migraine without aura (79%), followed by migraine with aura (12%) and chronic migraine (9%). The duration of vertigo attacks varied from seconds to days and 25% of patients had attacks that lasted less than 5 minutes. Among the patients with short-lasting attacks, 75% of these patients had ≥5 attacks per day within 72 hours. Auditory symptoms were reported in 36% of the patients. Migraine prophylactic treatments were effective in 77% of the patients.

Conclusions

Our study showed that the clinical features of vestibular migraine in China were similar to those of Western studies. The definition of vertigo episodes and migraine subtypes of vestibular migraine in International Classification of Headache Disorders 3rd edition beta version might be modified further. More than five vertigo attacks per day within 72 hours might be helpful as far as identifying vestibular migraine patients with short-lasting attacks.
Information: The source of entrepreneurial activity
Authors: Ortega Álvarez Ana Maria , García Merino Maria Teresa , Santos Álvarez Maria Valle
Published: May 2015

This article seeks to explore the influence of information and managerial perception on the development of business capabilities and entrepreneurial activity. For this purpose, we apply an exploratory analysis adopting a qualitative approach. Specifically, we study one emerging sector – personal food shopper – by means of news in media and interviews with entrepreneurs in the sector, in an attempt to examine how information shapes the dynamic capabilities which steer entrepreneurial activity. By examining the answers provided by the entrepreneurs, we pinpoint which topics make up their attention focus and that lead them to act selectively when faced with a variety of informative stimuli. Finally, we highlight the central role played by information as a resource to guide and shape entrepreneurial activity. The link between information and the creation of any new activity is increasingly being recognized through the dynamic capabilities approach. Nevertheless, the empirical evidence supporting these formulations remains scarce due to the difficulty inherent in representing such notions. Our paper contributes towards furthering current understanding of this empirical strand by conducting an exploratory study and adopting a qualitative methodology.
Fugitive Hydrography: The Nautical Magazine and the Hydrographic Office of the Admiralty, c.1832–1850
Authors: Barford Megan
Published: May 2015

This article examines the Nautical Magazine and its relationship with the Hydrographic Office of the British Admiralty in the early nineteenth century. It suggests how the magazine functioned as an organ for the dissemination and collection of useful knowledge in its endeavour to improve the Royal and Merchant navies. The periodical also presented the work of an emergent maritime science community in the Hydrographic Office, and served as a forum for the encouragement of engagement with naval science. Using archival material from the Hydrographic Office, which refers to, or was reproduced in the magazine, the article explores some of the ambiguities of a journalistic venture supported by the state in a period in which the organization and role of key public institutions were being redefined.
Between rivers and the sea: The Hellenic aquatic divisions
Authors: Kostuch Lucyna
Published: May 2015

It would seem that the view of the river flowing into the sea was, for the Greeks, a natural phenomenon, unworthy of special attention – as it is for us. Nothing could be further from the truth. A careful analysis of the extant sources leads to the conclusion that the Greeks perceived a strong distinction between the rivers and the sea. Moreover, they perceived this distinction as part of the natural mechanism, not some quirk of nature that could only be recorded in the realm of paradoxography. Moreover, in terms of géographie imaginaire, the innate ‘disagreement’ between the rivers and the sea – naturally predestined to each other’s existence – went beyond the usual aquatic division and opposition between the land and sea. This raises the question of how important this natural disagreement was to Greek culture. It turns out that perceptions about the organization of water resources reveal the Hellenic tendency to use the spatial location to explain cultural differences, political particularism and the fear of loss of historical memory. Thus, the strong distinction between the rivers and the sea is part of the Greek cultural heritage.
The Fairplay freights: Compiling a dataset of interwar coal freight rates
Authors: Castelein R. B.
Published: May 2015

The interwar period presents a challenge to maritime economic historians due to the lack of quality data. To improve our understanding of freight rate development during this period, I have compiled a dataset of coal freight rates from the United Kingdom, based on the lists of fixtures in Fairplay magazine. In this article, I discuss the source material and data collection process, compare the Fairplay data to other sources on interwar freights and present a preliminary survey of the data. Due to the large number of observations and the high degree of detail in the data, the new Fairplay dataset presents promising opportunities for further research into interwar shipping.
Whom Do Migrant Home Care Workers Contact in the Case of Work-Related Abuse? An Exploratory Study of Help-Seeking Behaviors
Authors: Green Ohad , Ayalon Liat
Published: May 2015

Migrant home care workers constitute an “invisible” and vulnerable group in society, as they work in isolation in the homes of frail older adults. Past research has shown that this population is particularly vulnerable to work-related abuse. The aim of the present study was to explore the help-seeking behaviors of migrant home care workers who were exposed to work-related abuse. Overall, 187 Filipino home care workers completed a self-report questionnaire regarding four types of work-related abuse (sexual, physical, emotional, and exploitation), help-seeking strategies (i.e., formal and informal reporting), and reasons for not disclosing abusive incidents. A total of 56.7% reported some type of abuse. Of these, less than half reported the abuse, mostly informally to family and friends. None reported the abuse to the police. Main reasons for not disclosing the abuse were fears that things would get worse and the belief that it will take too much time and effort. The findings demonstrate that migrant home care workers are highly vulnerable to work-related abuse but are not likely to report work-related abuse and put an end to the cycle of abuse and violence. This calls for the development of further policy and interventions to protect this already vulnerable population.
Depolicing: Rhetoric or Reality?
Authors: Oliver Willard M.
Published: May 2015

While the topic of depolicing is often discussed in political rhetoric, media reporting, and reports on police behavior, there exists little empirical analysis of the phenomenon at the police officer (individual) level. To further our understanding of the phenomenon of depolicing, the present study draws on a convenience sample of 25 police officers from across the United States to provide an inductive understanding of the nature, scope, and causes of depolicing. Among the findings is a strong belief that depolicing is a real and growing phenomenon, that it is more widespread than most agencies are willing to admit, and that its causes are highly varied, but include civil litigation, new laws and policies, and accusations of racial profiling. The article discusses the implications of depolicing and the need for future research.
Distributed leadership in English schools in 2014
Authors: Parker Gemma
Published: May 2015

For English primary schools, the framework of distributed leadership has been growing in status for a number of years and is now deemed to be the dominant model. However, the landscape has altered quite significantly for primary schools and their staff since the Coalition government took office in 2010, effecting fast-paced and wide-ranging reform. Therefore, it is a timely matter to consider whether a distributed model of leadership remains useful and appropriate for primary schools in 2014. In order to do so, this article identifies five defining features of the current context to use as a lens through which to scrutinise the distributed leadership model.
On the role of habitus and field in apprenticeships
Authors: Lehmann Wolfgang , Taylor Alison
Published: May 2015

Habitus is generally discussed in relation to academic forms of education. In other words, a working-class habitus disadvantages students in academic subjects or higher education. In contrast, it is often assumed that students who struggle with academic demands (perhaps because of habitus dislocation) can be served by vocational programmes such as apprenticeships, regardless of their social backgrounds or their habitus. Drawing on interviews with young men and women who participated in a high school-based apprenticeship programme in the Canadian provinces of Alberta and Ontario, this article argues that a closer consideration of the relationships between habitus and field are necessary in order to make apprenticeships a viable alternative for a larger number of young people.
Flexible working and work–life balance: midwives’ experiences and views
Authors: Prowse Julie , Prowse Peter
Published: May 2015

This article presents midwives’ views and experiences of flexible working and work–life balance. Both flexible working and work–life balance are important contemporary agendas within midwifery and can have both positive and negative consequences for midwives. Full-time midwives and those without caring commitments feel disadvantaged by flexible working and work–life balance policies as they have to fit when they work around part-time midwives and are increasingly expected to cover extra work. They feel their work–life balance is marginalized and this is fuelling discontent and resentment among midwives and leading to divisions between full- and part-time staff that reinforce flexibility stigma. Although flexible working and work–life balance are important for recruiting and retaining midwives they are part of the ongoing tensions and challenges for midwives and the midwifery profession.
Running with ‘wolves’ or waiting for a happy release? Evaluating routes to gender equality
Authors: Beirne Martin , Wilson Fiona
Published: May 2015

This article examines contemporary thinking about viable ways forward for gender equality at work. It questions both the lingering attachment to feminization in popular commentary and the renewed interest in positive discrimination within academic circles. Focusing on pay disparities in the public sector, it argues that greater attention should be given to the frontline agency of disadvantaged women and the material conditions that affect equality activism. Tensions in equality bargaining are highlighted, along with contradictory pressures on trade union intervention. ‘No-win-no-fee’ lawyers are considered to be neglected third party agents with greater relevance for representation and mobilization than the literature typically acknowledges, some proving to be highly effective in politicizing pay inequality.
Bounded or boundaryless? An empirical investigation of career boundaries and boundary crossing
Authors: Rodrigues Ricardo , Guest David , Budjanovcanin Alexandra
Published: May 2015

The article argues that the long-running debate between organizationally bounded and boundaryless careers has been too narrow and neglects the variety and distinctive characteristics of career boundaries. Drawing on boundary theory, it investigates the main career-relevant domains and boundaries, and the motivations and structural conditions that influence boundary crossing or having a career within a specific domain among a sample of professional pharmacists. The qualitative study shows that careers are enacted within a number of relevant domains and are shaped by a range of boundaries such that boundarylessness and embeddedness are co-existing career dimensions. It also reveals how even within a professional population careers are embedded within diverse social and cultural contexts that impose differing constraints on career mobility. The article therefore provides a fuller, more nuanced understanding of career boundaries and contemporary careers.
Reflexivity
Authors: Enosh Guy , Ben-Ari Adital
Published: May 2015

Reflexivity is defined as the constant movement between being in the phenomenon and stepping outside of it. In this article, we specify three foci of reflexivity—the researcher, the participant, and the encounter—for exploring the interview process as a dialogic liminal space of mutual reflection between researcher and participant. Whereas researchers’ reflexivity has been discussed extensively in the professional discourse, participants’ reflexivity has not received adequate scholarly attention, nor has the promise inherent in reflective processes occurring within the encounter.
Low-Dose 3-Factor Prothrombin Complex Concentrate for Warfarin Reversal Prior to Heart Transplant
Authors: Kantorovich Alexander , Fink Jodie M. , Militello Michael A. , Wanek Matthew R. , Smedira Nicholas G. , Soltesz Edward G. , Moazami Nader
Published: May 2015

Background: Anticoagulation with warfarin is common in patients presenting for heart transplant. Prior to surgery, anticoagulation reversal is necessary to avoid significant intraoperative and perioperative bleeding complications. Commonly, warfarin reversal is achieved with vitamin K and fresh frozen plasma (FFP); however, these therapies have significant limitations. An alternative to FFP for reversal exists with prothrombin complex concentrate (PCC). A warfarin reversal protocol prior to heart transplant was implemented using low-dose PCC at our institution. Objective: To assess blood product use, effectiveness, and safety post–low-dose PCC administration in patients needing warfarin reversal prior to heart transplant compared with historical controls. Methods: This was a single-center, retrospective cohort study. The PCC cohort included patients undergoing heart transplant presenting with an international normalized ratio ≥1.5 on warfarin therapy and who received at least 1 dose of PCC. Blood product use was measured from postoperative day 0 to 2. Results: The PCC and historical control cohorts included 16 and 50 patients, respectively. There was a significant reduction in the use of FFP (4 vs 8 units, P = 0.0239) in the PCC cohort compared with the historical control cohort. No differences were identified in the use of other blood products as well as other secondary efficacy or safety end points. Conclusions: Use of PCC, per the reversal protocol, prior to heart transplant reduced FFP use and showed a non–statistically significant trend toward reductions in the use of other blood products in the intraoperative and perioperative setting, with no difference identified in thrombotic or embolic complications compared with historical controls.
A novel method for the identification of a model for the nonlinear characteristic of a bolted lap-joint
Authors: Naraghi Tahereh , Nobari Ali S
Published: May 2015

Joints are the main source of nonlinearity and energy dissipation in large assembled structures which could be otherwise considered as linear. Consequently, modeling and parameter identification of joints play a significant role in any successful design and finite element (FE) modeling of structures. In the present research, an identification procedure is proposed for the modeling of the nonlinear behavior of a bolted joint. The main emphasis are placed on the simplicity of the experimental procedures involved as well as ease of incorporation of the identified model in the FE model of the structure. Using the concept of the optimum equivalent linear frequency response function, structure was excited by two levels of random force, at two bolt preload levels, and then the eigen values of the nonlinear structure and the inverse eigen-sensitivity identification technique are used, in order to identify the nonlinear properties of bolted joints. The results of implementing the method are promising and indicative of the fact that, in contrast to static Iwan’s model of a bolted joint, the equivalent dynamic characteristics of a bolted joint may be frequency dependent, as the different modes will affect the interface zone of the jointed structures in a different manner.
Casting a Long Shadow? Cross-border Spillovers of Shadow Economy across American States
Authors: Goel Rajeev K. , Saunoris James W.
Published: May 2015

This article examines the determinants of the shadow economy across American states, with emphasis on cross-border spillover effects. Results show positive spillovers of shadow activities across state borders with different specifications. In other effects, greater unionization in a state induces businesses to go underground, while states without a sales tax had a smaller shadow economy, ceteris paribus. Greater state product checked shadow growth, with military and nonmilitary state products having opposite effects. Finally, states bordering Canada and Mexico had different flows from the shadow sector.
Large-scale genome-wide association studies on a GPU cluster using a CUDA-accelerated PGAS programming model
Authors: González-Domínguez Jorge , Kässens Jan Christian , Wienbrandt Lars , Schmidt Bertil
Published: May 2015

Detecting epistasis, such as 2-SNP interactions, in genome-wide association studies (GWAS) is an important but time consuming operation. Consequently, GPUs have already been used to accelerate these studies, reducing the runtime for moderately-sized datasets to less than 1 hour. However, single-GPU approaches cannot perform large-scale GWAS in reasonable time. In this work we present multiEpistSearch, a tool to detect epistasis that works on GPU clusters. While CUDA is used for parallelization within each GPU, the workload distribution among GPUs is performed with Unified Parallel C+ + (UPC+ +), a novel extension of C+ + that follows the Partitioned Global Address Space (PGAS) model. multiEpistSearch is able to analyze large-scale datasets with 5 million SNPs from 10,000 individuals in less than 3 hours using 24 NVIDIA GTX Titans.
The Policy of Enforcement
Authors: Eger Robert J. , Fortner C. Kevin , Slade Catherine P.
Published: May 2015

We explore the question of whether some of the often conflicting evidence of racial profiling can be cleared up using red light camera observations to measure racial disparities in traffic violations. Using data from cameras at intersections matched to census data, we find that although citations from the red light cameras are issued to a disproportionate number of minorities based on the racial composition of the surrounding location, the racial composition of the violator is consistent with the racial composition of the block group in which they reside. Our study indicates that red light cameras may have a present and future role in assisting public policy makers on issues of racial profiling thresholds.
Confronting the hype
Authors: Brandusescu Ana , Sieber Renée E , Jochems Sylvie
Published: May 2015

Crisis mapping has emerged as a method of connecting and empowering citizens during emergencies. This article explores the hyperbole behind crisis mapping as it extends into more long-term or ‘chronic’ community development practices. We critically examined developer issues and participant (i.e. community organization) usage within the context of local communities. We repurposed the predominant crisis mapping platform Crowdmap for three cases of community development in Canadian anglophone and francophone. Our case studies show mixed results about the actual cost of deployment, the results of disintermediation, and local context with the mapping application. Lastly, we discuss the relationship of hype, temporality, and community development as expressed in our cases.
Celebrity witnessing: Shifting the emotional address in narratives of development aid
Authors: Christiansen Lene Bull , Frello Birgitta
Published: May 2015

This article deals with emotional address in the narrative modality of celebrity witnessing in the marketing of development aid. We analyse Danish celebrity narratives of global caring, drawing on Luc Boltanski’s work on a ‘politics of pity’, Lilie Chouliaraki’s notion of the ‘aspirational discourse’ and Sara Ahmed’s engagement with the concept of ‘orientation’. We argue that while criticising the dominant narrative modality is highly relevant, there is a risk that a too narrow focus on its reproduction can bar our view of the fact that it also enables discursive completions that can engage the spectator in alternative ways, thus creating space for alternative types of emotional engagement. The analysis demonstrates that the narrative modality of celebrity witnessing is more flexible than what is usually presumed, since it enables different completions and can be pried open for articulations of different kinds of passion.
Consumption in the city: The turn to interiority in contemporary postfeminist television
Authors: Dejmanee Tisha
Published: May 2015

In this article, I discuss a postfeminist ‘turn to interiority’ which takes place in US postfeminist television from 2005 onwards. Drawing on the theoretical critiques of postfeminist retreatism and girlie femininity, this turn is characterised by a concern with interior spaces – reviving domesticity and the importance of finding and securing a home – as well as internalised consumption – replacing forms of material consumption with the quest for self-actualisation, particularly through eating and expressions of the authentic self. I analyse this shift through a comparative analysis of the television shows Sex and the City, Girls and The Mindy Project. I argue that the turn to interiority is a product of the US cultural context, but also that this examination evidences the malleability and longevity of postfeminist ideology. Accordingly, I argue for the continuing importance of critical scholarship on postfeminism as an insight into the failures and pervasiveness of neoliberal politics.
Charity, signaling, and welfare
Authors: Brokensha Haley , Eriksson Lina , Ravenscroft Ian
Published: May 2015

Voices on the political right have long claimed that the welfare state ought to be kept small, and that charities can take over many of the tasks involved in helping those at the bottom of society. The arguments in favor of this claim are controversial, but even if they are accepted at face value the policy proposal remains problematic. For the proposal presupposes that charities would, in fact, be able to raise enough money to provide adequate help to those in need, and therefore assumes that charities are able to very significantly increase the number and/or size of donations they receive. We argue that there are good reasons for doubting that charities will be able to do this. Our argument turns on the fact that the most powerful strategy for eliciting donations—namely, allowing donors to use their donation to signal their pro-sociality—has an inbuilt upper limit. If too much emphasis is placed on the signaling opportunities donating to charity provides, donating no longer functions as an effective signal and the motivation to donate declines.
Management of a Type Ia Endoleak With the Nellix Endovascular Aneurysm Sealing System
Authors: Hughes Cían O. , de Bruin Jorg L. , Karthikesalingam Alan , Holt Peter J. , Loftus Ian M. , Thompson Matt M.
Published: May 2015

Purpose: To report the application of the Nellix endovascular aneurysm sealing (EVAS) device, including two chimney grafts, to successfully treat a type Ia endoleak. Case Report: An 87-year-old man had an asymptomatic 7.6-cm infrarenal abdominal aortic aneurysm (AAA) and a 4.5-cm right internal iliac artery aneurysm treated using an aortouni-iliac stent-graft. Two years after the index endovascular repair, an asymptomatic type Ia endoleak was detected on duplex ultrasound; the computed tomographic angiogram (CTA) demonstrated significant sac enlargement and stent-graft migration. Initial attempts to treat the leak with 2 aortic cuffs only reduced the size of the endoleak. Another procedure was undertaken using the Nellix device with chimney grafts to increase the proximal sealing zone above the existing stent-graft. Imaging postoperatively demonstrated successful resolution of the endoleak and continuing patency of both renal artery chimney stent-grafts. CTA at 6 months demonstrated persistent sealing of the endoleak. Conclusion: The use of the EVAS system may represent another endovascular solution that can be added to the clinician’s repertoire for treating type Ia endoleak after conventional endovascular repair of infrarenal AAA.
Stent Fractures After Superficial Femoral Artery Stenting
Authors: Lin Yuting , Tang Xiao , Fu Weiguo , Kovach Richard , George Jon C. , Guo Daqiao
Published: May 2015

Purpose: To determine the risk factors and clinical impact of stent fractures after superficial femoral artery (SFA) stenting. Methods: From May 2009 to June 2012, 171 consecutive patients (mean age 74.5±7.8, years; 106 men) who presented with SFA stenosis or occlusion in 205 limbs underwent stent implantation in the SFA at a single center. Stent fractures were determined by radiography and classified into types I through V. Loss of patency was assessed by duplex ultrasonography (>2.4 peak systolic velocity ratio) or angiography (percent diameter stenosis >50%). Results: The 12- and 24-month primary patency rates were 49.8% and 43.4%, respectively. Stent fractures occurred in 12.5% and 26.8% per limb (6.6% and 19.4% per stent) at 12 and 24 months, respectively. Primary patency was numerically worse in the stent fracture group but not statistically different from the group without fractures at 2 years. Primary patency for different classes of stent fracture were 30.8% (type I), 50.0% (type II), and 31.3% (type III–V). Hyperlipidemia (p=0.001), TransAtlantic Inter-Society Consensus II classification (p=0.007), chronic total occlusion (CTO; p<0.001), proximal lesion location (p=0.008), lesion calcification (p=0.025), total stent length (p=0.005), stent diameter (p=0.001), and number of stents (p=0.001) were statistically significant predictors of stent fracture. Multivariate analysis showed that CTO (hazard ratio 0.173, 95% confidence interval 0.042 to 0.716, p=0.015) was an independent predictor of stent fracture. Conclusion: Stent fractures occur more frequently in patients with CTOs after treatment of longer stented lesions. Although multivariate analysis showed that CTO was the only independent predictor regardless of stent length or number, the stent fracture rate was numerically higher in the severe calcification and proximal SFA lesion subgroups. Stent fracture did not appear to affect long-term patency rates, but this is yet to be confirmed with further follow-up.
Transcardiac Endograft Delivery for Endovascular Treatment of the Ascending Aorta
Authors: Wipper Sabine , Lohrenz Christina , Ahlbrecht Oliver , Carpenter Sebastian W. , Tsilimparis Nikolaos , Kersten Jan Felix , Detter Christian , Debus Eike S. , Kölbel Tilo
Published: May 2015

Purpose:

To compare the technical feasibility and hemodynamic alterations during antegrade transcardiac access routes vs conventional transfemoral access (TFA) for endovascular treatment of the ascending aorta in a porcine model.

Methods:

Antegrade transseptal access (TSA), transapical access (TAA), and TFA were used for implantation of custom-made endografts into the ascending aorta under fluoroscopy (6 pigs each). Hemodynamic parameters, myocardial and cerebral blood flow, and carotid artery blood flow were evaluated during baseline (T1), sheath advancement (T2), after sheath retraction (T3), and after endograft deployment (T4).

Results:

Endograft deployment was feasible in all animals; all coronary arteries remained patent. Hemodynamic parameters were comparable in all 3 study groups during all measurements. During T2, transient hemodynamic alteration occurred in all groups, with transient severe valve insufficiency in TSA and TAA reflected by the higher pulmonary to mean arterial pressure ratio (p<0.05) as compared with TFA. Values stabilized again at T3 and remained stable until T4. The innominate artery was partially occluded in 4 (TSA), 3 (TAA), and 5 (TFA) animals. There was no deterioration of myocardial or cerebral perfusion during the procedures. Endograft deployment and fluoroscopy times during TAA were shorter than in TSA and TFA.

Conclusions:

TSA, TFA, and TAA to the ascending aorta are feasible for endograft delivery to the ascending aorta in a porcine model. Transient hemodynamic instability in TSA and TAA recovered to near preoperative values. TAA appeared technically easier.
Observations on Surveillance Imaging After Endovascular Sealing of Abdominal Aortic Aneurysms With the Nellix System
Authors: McWilliams Richard G. , Fisher Robert K. , England Andrew , Torella Francesco
Published: May 2015

Purpose: To describe and interpret the findings of computed tomography images acquired before and after endovascular aneurysm sealing (EVAS) with the Nellix endoprosthesis and consider the potential implications of these findings on EVAS planning and performance. Methods: A retrospective review was performed of perioperative imaging from 30 consecutive patients (median age 79 years; 19 men) undergoing elective EVAS at our center between December 2013 and November 2014. The images were systematically reviewed specifically looking for endobag collapse, aortic thrombus compression, and aortic wall disruption according to definitions set a priori. Results: There was no perioperative mortality or endoleak after the EVAS procedure. Endobag collapse, which could potentially result in type II endoleak if occurring near a patent side branch, was seen in the endobags of 12 patients. Aortic thrombus compression, which affects the accuracy of preoperative volume measurements in predicting the amount of polymer needed to perform EVAS, was seen in 15 patients. There was one aortic wall disruption, which could potentially result in intraoperative hemorrhage, though this did not occur in this case. Conclusion: These observations and their potential implications should help clinicians in planning and performing EVAS, as well as in interpreting postoperative imaging.
Studying the Interaction of Stent-Grafts and Treated Abdominal Aortic Aneurysms
Authors: Georgakarakos Efstratios , Raptis Anastasios , Schoretsanitis Nikolaos , Bisdas Theodosios , Beropoulis Efthymios , Georgiadis George S. , Matsagkas Miltiadis , Xenos Michalis
Published: May 2015

Since the advent of endovascular repair of aortic aneurysms (EVAR), clinical focus has been on preventing loss of sealing at the level of the infrarenal neck, which leads to type I endoleak and repressurization of the aneurysm sac. Enhanced mechanisms for central fixation and seal have consequently lowered the incidence of migration and endoleaks. However, endograft limb thrombosis and its causal mechanisms have not been addressed adequately in the literature. This article reviews the pathophysiological mechanisms associated with limb thrombosis in order to facilitate better clinical judgment to prevent iliac adverse effects.