bluuebunny/crossref_metadata_2025 huggingface dataset:
MO‐F‐CAMPUS‐I‐02: Occupational Conceptus Doses From Fluoroscopically‐Guided Interventional Procedures
Authors: Damilakis J , Perisinakis K , Solomou G , Stratakis J
Published: June 2015

Purpose:

The aim of this method was to provide dosimetric data on conceptus dose for the pregnant employee who participates in fluoroscopically‐guided interventional procedures.

Methods:

Scattered air‐kerma dose rates were obtained for 17 fluoroscopic projections involved in interventional procedures. These projections were simulated on an anthropomorphic phantom placed on the examination table supine. The operating theater was divided into two grids relative to the long table sides. Each grid consisted of 33 cells spaced 0.50 m apart. During the simulated exposures, at each cell, scatter air‐kerma rate was measured at 110 cm from the floor i.e. at the height of the waist of the pregnant worker. Air‐kerma rates were divided by the dose area product (DAP) rate of each exposure to obtain normalized data. For each projection, measurements were performed for 3 kVp and 3 filtration values i.e. for 9 different x‐ray spectra. All measurements were performed by using a modern C‐arm angiographic system (Siemens Axiom Artis, Siemens, Germany) and a radiation meter equipped with an ionization chamber.

Results:

The results consist of 153 iso‐dose maps, which show the spatial distribution of DAP‐normalized scattered air‐kerma doses at the waist level of a pregnant worker. Conceptus dose estimation is possible using air‐kerma to embryo/fetal dose conversion coefficients published in a previous study (J Cardiovasc Electrophysiol, Vol. 16, pp. 1–8, July 2005). Using these maps, occupationally exposed pregnant personnel may select a working position for a certain projection that keeps abdominal dose as low as reasonably achievable. Taking into consideration the regulatory conceptus dose limit for occupational exposure, determination of the maximum workload allowed for the pregnant personnel is also possible.

Conclusion:

Data produced in this work allow for the anticipation of conceptus dose and the determination of the maximum workload for a pregnant worker from any fluoroscopically‐guided interventional procedure.

This study was supported by the Greek Ministry of Education and Religious Affairs, General Secretariat for Research and Technology, Operational Program ‘Education and Lifelong Learning’, ARISTIA (Research project: CONCERT).
TU‐AB‐BRD‐03: Fault Tree Analysis
Authors: Dunscombe P.
Published: June 2015

Current quality assurance and quality management guidelines provided by various professional organizations are prescriptive in nature, focusing principally on performance characteristics of planning and delivery devices. However, published analyses of events in radiation therapy show that most events are often caused by flaws in clinical processes rather than by device failures. This suggests the need for the development of a quality management program that is based on integrated approaches to process and equipment quality assurance. Industrial engineers have developed various risk assessment tools that are used to identify and eliminate potential failures from a system or a process before a failure impacts a customer. These tools include, but are not limited to, process mapping, failure modes and effects analysis, fault tree analysis. Task Group 100 of the American Association of Physicists in Medicine has developed these tools and used them to formulate an example risk‐based quality management program for intensity‐modulated radiotherapy. This is a prospective risk assessment approach that analyzes potential error pathways inherent in a clinical process and then ranks them according to relative risk, typically before implementation, followed by the design of a new process or modification of the existing process. Appropriate controls are then put in place to ensure that failures are less likely to occur and, if they do, they will more likely be detected before they propagate through the process, compromising treatment outcome and causing harm to the patient. Such a prospective approach forms the basis of the work of Task Group 100 that has recently been approved by the AAPM. This session will be devoted to a discussion of these tools and practical examples of how these tools can be used in a given radiotherapy clinic to develop a risk based quality management program.

Learning Objectives:

Learn how to design a process map for a radiotherapy process

Learn how to perform failure modes and effects analysis analysis for a given process

Learn what fault trees are all about

Learn how to design a quality management program based upon the information obtained from process mapping, failure modes and effects analysis and fault tree analysis.

Dunscombe: Director, TreatSafely, LLC and Center for the Assessment of Radiological Sciences; Consultant to IAEA and Varian

Thomadsen: President, Center for the Assessment of Radiological Sciences

Palta: Vice President of the Center for the Assessment of Radiological Sciences
TU‐AB‐BRB‐01: Coverage Evaluation and Probabilistic Treatment Planning as a Margin Alternative
Authors: Siebers J.
Published: June 2015

The accepted clinical method to accommodate targeting uncertainties inherent in fractionated external beam radiation therapy is to utilize GTV‐to‐CTV and CTV‐to‐PTV margins during the planning process to design a PTV‐conformal static dose distribution on the planning image set. Ideally, margins are selected to ensure a high (e.g. >95%) target coverage probability (CP) in spite of inherent inter‐ and intra‐fractional positional variations, tissue motions, and initial contouring uncertainties.

Robust optimization techniques, also known as probabilistic treatment planning techniques, explicitly incorporate the dosimetric consequences of targeting uncertainties by including CP evaluation into the planning optimization process along with coverage‐based planning objectives. The treatment planner no longer needs to use PTV and/or PRV margins; instead robust optimization utilizes probability distributions of the underlying uncertainties in conjunction with CP‐evaluation for the underlying CTVs and OARs to design an optimal treated volume.

This symposium will describe CP‐evaluation methods as well as various robust planning techniques including use of probability‐weighted dose distributions, probability‐weighted objective functions, and coverage optimized planning. Methods to compute and display the effect of uncertainties on dose distributions will be presented. The use of robust planning to accommodate inter‐fractional setup uncertainties, organ deformation, and contouring uncertainties will be examined as will its use to accommodate intra‐fractional organ motion. Clinical examples will be used to inter‐compare robust and margin‐based planning, highlighting advantages of robust‐plans in terms of target and normal tissue coverage. Robust‐planning limitations as uncertainties approach zero and as the number of treatment fractions becomes small will be presented, as well as the factors limiting clinical implementation of robust planning.

Learning Objectives:

To understand robust‐planning as a clinical alternative to using margin‐based planning.

To understand conceptual differences between uncertainty and predictable motion.

To understand fundamental limitations of the PTV concept that probabilistic planning can overcome.

To understand the major contributing factors to target and normal tissue coverage probability.

To understand the similarities and differences of various robust planning techniques

To understand the benefits and limitations of robust planning techniques
TU‐CD‐BRB‐06: Deciphering Genomic Underpinnings of Quantitative MRI‐Based Radiomic Phenotypes of Invasive Breast Carcinoma
Authors: Zhu Y , Li H , Guo W , Drukker K , Yang S , Lan L , Giger M , Ji Y ,   for the TCIA Breast Cancer Group
Published: June 2015

Purpose:

Magnetic Resonance Imaging(MRI) has been routinely used for diagnosis and assessment of breast cancer. Despite its wide applications in clinical practice, the relationship between the observed tumor MRI phenotypes and the genomic mechanism of tumorigenesis remains under‐explored, largely due to lack of data on both imaging and genomics for the same tumors.

Methods:

We combined data from The Cancer Genome Atlas(TCGA) and The Cancer Image Archive(TCIA), that included quantitatively extracted MRI phenotypes of 91 breast invasive carcinomas and their multi‐layer genomic data. Gene set enrichment analysis and regression analysis were performed to identify associations between tumor MRI radiomic phenotypes and various genomic and molecular subtypes of tumors. Patient groups defined by radiomic phenotypes and genomic platforms were also associated with tumor pathological stages and molecular receptor status using Fisher's exact test.

Results:

Significant associations (adjusted p‐values ≤ 0.1) were identified between radiomic phenotypes (characterizing tumor size, shape, margin, enhancement texture, and blood flow kinetics) and genomic features involved in multiple molecular regulation layers (including pathway gene expressions, pathway copy number variations, gene somatic mutations, miRNA expressions, and protein expressions). Transcriptional activities of various genetic pathways were dominantly positively associated with tumor size and blurred tumor margin. miRNA activity significantly associated with tumor size and enhancement textures, but not with phenotypes describing tumor shape, margin, and blood flow kinetics. Patient groups defined by radiomic phenotypes were associated with tumor T stage and overall stage (p‐values ≤ 0.072). Genomic platforms defined patient groups associated with the status of progesterone and estrogen receptors (p‐values ≤ 0.0000427) and pathological stages (p‐values ≤ 0.056).

Conclusion:

We present these findings as a resource shedding insight on the connection between underlying genetic mechanisms and observed tumor radiomic phenotypes, which forms a basis for future studies using non‐invasive MRI techniques for accurate cancer diagnosis and prognosis.
TU‐F‐CAMPUS‐I‐01: Statistical Iterative Reconstruction for Perfusion CT with a Prior‐Image Induced Hybrid Nonlocal Means Regularization
Authors: Li B , Lyu Q , Ma J , Wang J
Published: June 2015

Purpose:

In CT perfusion imaging, an initial phase CT acquired with a high‐dose protocol can be used to improve the image quality of later phase CT acquired with a low‐dose protocol. For dynamic regions, signals in the later low‐dose CT may not be completely recovered if the initial CT heavily regularizes the iterative reconstruction process. To overcome the limitation of the conventional prior image induced penalty, we propose a hybrid nonlocal means (NLM) regularization for iterative reconstruction of perfusion CT.

Methods:

The hybrid penalty is constructed by combining the NLM of initial high‐dose CT in the stationary region and later low‐dose CT in the dynamic region. The stationary and dynamic regions are determined by the similarity between the initial high‐dose scan and later low‐dose scan, where the similarity is defined as Gaussian distance between patch‐window of the same pixel of the two scans. The similarity measure is then used to weight the influence of the initial high‐dose CT. For regions with high similarity (e.g., stationary region), initial high‐dose CT will play a dominant role in regularizing the solution. For regions with low similarity (e.g., dynamic region), the regularization will rely on low‐dose scan itself. This new hybrid NLM (hNLM) penalty is then incorporated into the penalized weighted least‐squares (PWLS) for perfusion CT reconstruction. Digital and anthropomorphic phantom studies were performed to evaluate the PWLS‐hNLM algorithm.

Results:

Both phantom studies show that the PWLS‐hNLM algorithm is superior to the conventional penalty term without considering the signal changes within dynamic region. In the dynamic region, the reconstruction error measured by root mean square error is reduced by 50% in PWLS‐hNLM reconstructed image.

Conclusion:

The PWLS‐hNLM algorithm can effectively use initial high‐dose CT to reconstruct low‐dose perfusion CT in the stationary region while avoiding its influence in the dynamic region.
Determinants of PE Teachers Career Intentions
Authors: Mäkelä Kasper , Hirvensalo Mirja , Whipp Peter
Published: June 2015

One of the cause’s célèbre in the field of education has been teacher attrition; Physical education (PE) is no different. Some PE teachers are leaving the profession because they encounter stress and dissatisfaction in their profession. The purpose of this study is to determine the aspects that keep PE teachers happy and remaining in the profession. Seven job satisfaction factors were identified with principal component analysis and logistic regression models used to study the likelihood of teachers’ intention to stay in the profession. Those PE teachers who intended to stay in teaching were more satisfied with the resources, work community, their own expertise, recognition of teaching, manageability of work, students, as well as the quality of work. It was also found that satisfaction and commitment to teaching were strong predictors for staying in the profession. For early career teachers, manageability and quality of work were the factors that were strongly related to their intention to stay in the profession.
Hairpin Telomere Resolvases
Authors: Kobryn Kerri , Chaconas George
Published: June 2015

Covalently closed hairpin ends, also known as hairpin telomeres, provide an unusual solution to the end replication problem. The hairpin telomeres are generated from replication intermediates by a process known as telomere resolution. This is a DNA breakage and reunion reaction promoted by hairpin telomere resolvases (also referred to as protelomerases) found in a limited number of phage and bacteria. The reaction promoted by these enzymes is a chemically isoenergetic two-step transesterification without a requirement for divalent metal ions or high-energy cofactors and uses an active site and mechanism similar to that for type IB topoisomerases and tyrosine recombinases. The small number of unrelated telomere resolvases characterized to date all contain a central, catalytic core domain with the active site, but in addition carry variable C- and N-terminal domains with different functions. Similarities and differences in the structure and function of the telomere resolvases are discussed. Of particular interest are the properties of the
Borrelia
telomere resolvases, which have been studied most extensively at the biochemical level and appear to play a role in shaping the unusual segmented genomes in these organisms and, perhaps, to play a role in recombinational events.
Retroviral Integrase Structure and DNA Recombination Mechanism
Authors: Engelman Alan , Cherepanov Peter
Published: June 2015

Due to the importance of human immunodeficiency virus type 1 (HIV-1) integrase as a drug target, the biochemistry and structural aspects of retroviral DNA integration have been the focus of intensive research during the past three decades. The retroviral integrase enzyme acts on the linear double-stranded viral DNA product of reverse transcription. Integrase cleaves specific phosphodiester bonds near the viral DNA ends during the 3′ processing reaction. The enzyme then uses the resulting viral DNA 3′-OH groups during strand transfer to cut chromosomal target DNA, which simultaneously joins both viral DNA ends to target DNA 5′-phosphates. Both reactions proceed via direct transesterification of scissile phosphodiester bonds by attacking nucleophiles: a water molecule for 3′ processing, and the viral DNA 3′-OH for strand transfer. X-ray crystal structures of prototype foamy virus integrase-DNA complexes revealed the architectures of the key nucleoprotein complexes that form sequentially during the integration process and explained the roles of active site metal ions in catalysis. X-ray crystallography furthermore elucidated the mechanism of action of HIV-1 integrase strand transfer inhibitors, which are currently used to treat AIDS patients, and provided valuable insights into the mechanisms of viral drug resistance.
Host Factors in Retroviral Integration and the Selection of Integration Target Sites
Authors: Craigie Robert , Bushman Frederic D.
Published: June 2015

In order to replicate, a retrovirus must integrate a DNA copy of the viral RNA genome into a chromosome of the host cell. The study of retroviral integration has advanced considerably in the past few years. Here we focus on host factor interactions and the linked area of integration targeting. Genome-wide screens for cellular factors affecting HIV replication have identified a series of host cell proteins that may mediate subcellular trafficking for preintegration complexes, nuclear import, and integration target site selection. The cell transcriptional co-activator protein LEDGF/p75 has been identified as a tethering factor important for HIV integration, and recently, BET proteins (Brd2, 4, and 4) have been identified as tethering factors for the gammaretroviruses. A new class of HIV inhibitors has been developed targeting the HIV-1 IN-LEDGF binding site, though surprisingly these inhibitors appear to block assembly late during replication and do not act at the integration step. Going forward, genome-wide studies of HIV–host interactions offer many new starting points to investigate HIV replication and identify potential new inhibitor targets.
vlsAntigenic Variation Systems of Lyme DiseaseBorrelia: Eluding Host Immunity through both Random, Segmental Gene Conversion and Framework Heterogeneity
Authors: Norris Steven J.
Published: June 2015

Spirochetes that cause Lyme borreliosis (also called Lyme disease) possess thevlslocus, encoding an elaborate antigenic variation system. This locus contains the expression sitevlsEas well as a contiguous array ofvlssilent cassettes, which contain variations of the central cassette region ofvlsE. The locus is present on one of the many linear plasmids in the organism, e.g. plasmid lp28-1 in the strainBorrelia burgdorferiB31. Changes in the sequence ofvlsEoccur continuously during mammalian infection and consist of random, segmental, unidirectional recombination events between the silent cassettes and the cassette region ofvlsE. These gene conversion events do not occur duringin vitroculture or the tick portion of the infection cycle ofB. burgdorferior the other relatedBorreliaspecies that cause Lyme disease. The mechanism of recombination is largely unknown, but requires the RuvAB Holliday junction branch migrase. Other features of thevlslocus also appear to be required, includingcislocations ofvlsEand the silent cassettes and high G+C content and GC skew. Thevlssystem is required for long-term survival of LymeBorreliain infected mammals and represents an important mechanism of immune evasion. In addition to sequence variation, immune selection also results in significant heterogeneity in the sequence of the surface lipoprotein VlsE. Despite antigenic variation, VlsE generates a robust antibody response, and both full-length VlsE and the C6 peptide (corresponding to invariant region 6) are widely used in immunodiagnostic tests for Lyme disease.
V(D)J Recombination: Mechanism, Errors, and Fidelity
Authors: Roth David B.
Published: June 2015

V(D)J recombination, the mechanism responsible for generating antigen receptor diversity, has the potential to generate aberrant DNA rearrangements in developing lymphocytes. Indeed, the recombinase has been implicated in several different kinds of errors leading to oncogenic transformation. Here we review the basic aspects of V(D)J recombination, mechanisms underlying aberrant DNA rearrangements, and the types of aberrant events uncovered in recent genomewide analyses of lymphoid neoplasms.
Xer Site-Specific Recombination: Promoting Vertical and Horizontal Transmission of Genetic Information
Authors: Midonet Caroline , Barre Francois-Xavier
Published: June 2015

Two related tyrosine recombinases, XerC and XerD, are encoded in the genome of most bacteria where they serve to resolve dimers of circular chromosomes by the addition of a crossover at a specific site,
dif
. From a structural and biochemical point of view they belong to the Cre resolvase family of tyrosine recombinases. Correspondingly, they are exploited for the resolution of multimers of numerous plasmids. In addition, they are exploited by mobile DNA elements to integrate into the genome of their host. Exploitation of Xer is likely to be advantageous to mobile elements because the conservation of the Xer recombinases and of the sequence of their chromosomal target should permit a quite easy extension of their host range. However, it requires means to overcome the cellular mechanisms that normally restrict recombination to
dif
sites harbored by a chromosome dimer and, in the case of integrative mobile elements, to convert dedicated tyrosine resolvases into integrases.
Phage-encoded Serine Integrases and Other Large Serine Recombinases
Authors: Smith Margaret C. M.
Published: June 2015

The large serine recombinases (LSRs) are a family of enzymes, encoded in temperate phage genomes or on mobile elements, that precisely cut and recombine DNA in a highly controllable and predictable way. In phage integration, the LSRs act at specific sites, the
attP
site in the phage and the
attB
site in the host chromosome, where cleavage and strand exchange leads to the integrated prophage flanked by the recombinant sites
attL
and
attR
. The prophage can excise by recombination between
attL
and
attR
but this requires a phage-encoded accessory protein, the recombination directionality factor (RDF). Although the LSRs can bind specifically to all the recombination sites, only specific integrase-bound sites can pair in a synaptic complex prior to strand exchange. Recent structural information has led to a breakthrough in our understanding of the mechanism of the LSRs, notably how the LSRs bind to their substrates and how LSRs display this site-selectivity. We also understand that the RDFs exercise control over the LSRs by protein–protein interactions. Other recent work with the LSRs have contributed to our understanding of how all serine recombinases undergo strand exchange subunit rotation, facilitated by surfaces that resemble a molecular bearing.
Reset osmostat: a rare cause of hyponatraemia
Authors: Vale Beatriz Maia , Morais Sofia , Mesquita Joana , Mimoso Gabriela
Published: June 2015

Neonatal hyponatraemia is common, and related to significant morbidity and mortality. We report a case of a preterm newborn (gestational age of 36 weeks) with hyponatraemia, and with a prenatal diagnosis of cleft lip and palate, with a normal fetal karyotype. On the seventh day of life, a biochemical evaluation for jaundice and mild signs of dehydration showed hyponatraemia of 124 mmol/L. Investigation showed normal adrenal and thyroid functions, plasma hyposmolality (258 mOsm/kg); high urinary sodium (73 mmol/L) and high urinary osmolality (165 mOsm/kg). Despite oral sodium supplementation and fludrocortisone treatment, sodium levels remained between 124 and 130 mmol/L. Cranial ultrasound, brain MRI and renal ultrasound were normal. The diagnosis of hyponatraemia was unpredicted and the investigation was suggestive of reset osmostat, a subtype of the syndrome of inappropriate secretion of antidiuretic hormone, characterised by a subnormal threshold for antidiuretic hormone secretion.
Initial experience of coiling cerebral aneurysms using the new Comaneci device
Authors: Lawson Aimee Louise Deborah , Chandran Arun , Puthuran Mani , Goddard Tony , Nahser Hans , Patankar Tufail
Published: June 2015

We present our initial patient experience with an innovative temporary bridging device, the Comaneci (Rapid Medical, Israel), to assist in the coiling of cerebral aneurysms. The Comaneci device confers the same benefits as balloon remodeling but without the risks of parent artery occlusion. This alleviates time pressure on the clinician, and could reduce the risk of parent artery thrombosis. Three patients were treated with the Comaneci device. Two patients had acute ruptured posterior communicating aneurysms and one patient was treated electively for a carotico-ophthalmic aneurysm. Excellent occlusion of all three aneurysms was obtained. One patient developed a distal middle cerebral artery clot, that was treated with intravenous aspirin, with minor neurological consequences. These early results show that the Comaneci device can be used to achieve good cerebral aneurysm occlusion. Vessel patency is maintained throughout the procedure with potential advantages over conventional balloon assisted coiling.
An unusual case of invasive aspergillosis in an immunocompetent individual
Authors: Mohammed Afsal P , Dhunputh Pushwinder , Chiluka Raghuvaran , Umakanth Shashikiran
Published: June 2015

Invasive aspergillosis is a highly lethal opportunistic infection that poses a significant threat to immunocompromised patients. With studies suggesting that the incidence of this disease is increasing, and mortality rates remain high, early diagnosis and treatment are very important to improve patient survival. We present the case of a 33-year-old immunocompetent woman who presented with a history of cough and severe breathlessness, and was diagnosed to have invasive aspergillosis. This case emphasises the importance of maintaining a high index of suspicion and also of remembering that invasive aspergillosis is no longer only a disease of immunocompromised individuals. In addition, this case tells us that aspergillosis is one of the new emerging infections in intensive care units.
Spatiotemporal patterns of rockfish bycatch in US west coast groundfish fisheries: opportunities for reducing incidental catch of depleted species
Authors: Bjorkland Rhema , Dunn Daniel C. , McClure Michelle , Jannot Jason , Bellman Marlene A. , Gleason Mary , Schiffers Katja
Published: June 2015

Spatial and temporal management measures to reduce nontarget catch are important strategies for rebuilding overfished rockfish (Sebastes spp.) populations in the Northeast Pacific. We describe efforts to support reducing rockfish bycatch in central California trawl fisheries by testing the efficacy of move-on rules on catch data from 2002 to 2010. Move-on rules are regulations or guidelines that trigger the temporary closure of a fishery in a targeted area when a bycatch threshold is reached, without the closure of the entire fishery. Move-on rules based on spatiotemporal autocorrelation (clustering) were effective in reducing bycatch with modest impact on target catch, removing between 35% and 77% of future hauls with bycatch within a specified distance and time of a bycatch-containing haul, while foregoing target catch by an average of 12%. The spatial and temporal peak clustering scales show correlation with the level of schooling behavior by each species; however, the efficiency of the rules measured either in reduction in bycatch hauls or diminished target catch was not strongly affected by those aggregation behaviors. Our analysis provides information for fishers, such as those in the California Risk Pool, in the continuing development of responses that are more refined in both scale and impact.
Detecting regime shifts in fish stock dynamics
Authors: Perälä Tommi , Kuparinen Anna
Published: June 2015

Environmental factors such as water temperature, salinity, and the abundance of zooplankton can have major effects on certain fish stocks’ ability to produce juveniles and, thus, stock renewal ability. This variability in stock productivity manifests itself as different productivity regimes. Here, we detect productivity regime shifts by analyzing recruit-per-spawner time series with Bayesian online change point detection algorithm. The algorithm infers the time since the last regime shift (change in mean or variance or both) as well as the parameters of the data-generating process for the current regime sequentially. We demonstrate the algorithm’s performance using simulated recruitment data from an individual-based model and further apply the algorithm to stock assessment estimates for four Atlantic cod (Gadus morhua) stocks obtained from RAM legacy database. Our analysis shows that the algorithm performs well when the variability between the regimes is high enough compared with the variability within the regimes. The algorithm found several productivity regimes for all four cod stocks, and the findings suggest that the stocks are currently in low productivity regimes, which have started during the 1990s and 2000s.
Global sensitivity analysis for the Rothermel model based on high-dimensional model representation
Authors: Liu Yaning , Hussaini M. Yousuff , Ökten Giray
Published: June 2015

Rothermel’s wildland surface fire spread model is widely used in North America. The model outputs depend on a number of input parameters, which can be broadly categorized as fuel model, fuel moisture, terrain, and wind parameters. Due to the inevitable presence of uncertainty in the input parameters, knowing the sensitivity of the model output to a given input parameter can be very useful for understanding and controlling the sources of parametric uncertainty. Instead of obtaining the local sensitivity indices, we perform a global sensitivity analysis that considers the synchronous changes of parameters in their respective ranges. The global sensitivity indices corresponding to different parameter groups are computed by constructing the truncated ANOVA – high dimensional model representation for the model outputs with a polynomial expansion approach. We apply global sensitivity analysis to six standard fuel models, namely short grass, tall grass, chaparral, hardwood litter, timber, and light logging slash. Our sensitivity results show similarities, as well as differences, between fuel models. For example, the sensitivities of the input parameters, i.e., fuel depth, low heat content, and wind, are large in all fuel models and as high as 85% of the total model variance in the fuel model light logging slash. On the other hand, the fuel depth explains around 40% of the total variance in the fuel model light logging slash but only 12% of the total variance in the fuel model short grass. The quantification of the importance of parameters across fuel models helps identify the parameters for which additional resources should be used to lower their uncertainty, leading to effective fire management.
Work-Competitive Scheduling on Task Dependency Graphs
Authors: Kari Chadi , Russell Alexander , Shashidhar Narasimha
Published: June 2015

A fundamental problem in distributed computing is the task of cooperatively executing a given set of [Formula: see text] tasks by [Formula: see text] asynchronous processors where the communication medium is dynamic and subject to failures. Also known as do-all, this problem been studied extensively in various distributed settings. In [2], the authors consider a partitionable network scenario and analyze the competitive performance of a randomized scheduling algorithm for the case where the tasks to be completed are independent of each other. In this paper, we study a natural extension of this problem where the tasks have dependencies among them. We present a simple randomized algorithm for [Formula: see text] processors cooperating to perform [Formula: see text] known tasks where the dependencies between them are defined by a [Formula: see text]-partite task dependency graph and additionally these processors are subject to a dynamic communication medium. By virtue of the problem setting, we pursue competitive analysis where the performance of our algorithm is measured against that of the omniscient offline algorithm which has complete knowledge of the dynamics of the communication medium. We show that the competitive ratio of our algorithm is tight and depends on the dynamics of the communication medium viz. the computational width defined in [2] and also on the number of partitions of the task dependency graph.
Some remarks on the use of effective Lagrangians in QED and QCD
Authors: Dittrich Walter
Published: June 2015

We discuss in this paper the usefulness of the effective Lagrangians [Formula: see text] of QED and QCD within the one-loop approximation. Instead of calculating [Formula: see text] via complicated computations with Schwinger’s proper-time technique or Feynman graphs, we prefer to employ the energy–momentum tensor and the leading-log model. The advantage is that we do not have to demand the external electromagnetic or color field to be constant. There are also some critical remarks added which cast doubt on the use of [Formula: see text] with covariant constant fields in explaining the nature of the QCD vacuum.
Hidden Markov Model Decision Forest for Dynamic Facial Expression Recognition
Authors: Liang Jinglian , Xu Chao , Feng Zhiyong , Ma Xirong
Published: June 2015

Facial expressions can be mainly conveyed by only a few discriminative facial regions of interest. In this paper, we study the discriminative regions for facial expression recognition from video sequences. The goal of our method is to explore and make use of the discriminative regions for different facial expressions. For this purpose, we propose a Hidden Markov Model (HMM) Decision Forest (HMMDF). In this framework, each tree node is a discriminative classifier, which is constructed by combining weighted HMMs. Motivated by a psychological theory of "elimination by aspects", several HMMs on each node are modeled respectively for facial regions, which have discriminative capabilities for classification. The weights for these HMMs can be further adjusted according to the contributions of facial regions. Extensive experiments validate the effectiveness of discriminative regions on facial expression, and the experimental results show that the proposed HMMDF framework yields dramatic improvements in facial expression recognition compared to existing methods.
Misleading inferences from discretization of empty spacetime: Snyder-noncommutativity case study
Authors: Amelino-Camelia Giovanni , Astuti Valerio
Published: June 2015

Alternative approaches to the study of the quantum gravity problem are handling the role of spacetime very differently. Some are focusing on the analysis of one or another novel formulation of "empty spacetime", postponing to later stages the introduction of particles and fields, while other approaches assume that spacetime should only be an emergent entity. We here argue that recent progress in the covariant formulation of quantum mechanics, suggests that empty spacetime is not physically meaningful. We illustrate our general thesis in the specific context of the noncommutative Snyder spacetime, which is also of some intrinsic interest, since hundreds of studies were devoted to its analysis. We show that empty Snyder spacetime, described in terms of a suitable kinematical Hilbert space, is discrete, but this is only a formal artifact: the discreteness leaves no trace on the observable properties of particles on the physical Hilbert space.
Spectrum for the electric dipole which nonradially falling into a black hole
Authors: Shatskiy Alexander , Novikov I. D. , Malinovsky Alexandr
Published: June 2015

In this paper, the electromagnetic bremsstrahlung spectrum of the dipole which falls along a spiral orbit into the Schwarzschild black hole was found. The characteristic features of this electromagnetic spectrum can be used for determination of the black hole mass. This new way (if implemented) provides higher accuracy of the determination of the black hole mass. Also these features in the spectrum can be used for the determination of the some physical processes in the black hole magnetosphere and in the accretion disk. It is also shown that the asymptotic behavior of this spectrum (at high frequencies) is practically independent from the impact parameter of the falling dipole.
Lateral-Torsional Buckling of Nonuniformly Loaded Beam Using Differential Transformation Method
Authors: Hołubowski Ryszard , Jarczewska Kamila
Published: June 2015

The paper presents the application of the differential transformation method (DTM) to the stability analysis of nonuniformly loaded beams under bending. The main advantage of the method is the possibility to obtain the semi-analytical solution for the critical loads of the beam undergoing lateral-torsional buckling. To determine the critical load, the system of two coupled ordinary differential equations with variable coefficients and parameters have to be solved. Numerical analyses were carried out for three different types of load functions: (i) Uniformly distributed load, (ii) linearly varying load and (iii) sinusoidally distributed load. The results were compared with the solutions computed by the finite element method (FEM) and those obtained by the authors using the variational iterative method (VIM). In each case, it was found that the difference with reference to the existing one does not exceed 3%, which testifies the effectiveness of the DTM used. Nevertheless, it should be emphasized that the number of terms of the approximation series used is fairly large and therefore the calculation of higher critical loads can be very time-consuming.
Collapse of Sharp-Notched 6061-T6 Aluminum Alloy Tubes Under Cyclic Bending
Authors: Chung Chen-Cheng , Lee Kuo-Long , Pan Wen-Fung
Published: June 2015

The mechanical behavior and buckling failure of sharp-notched 6061-T6 aluminum alloy tubes with different notch depths subjected to cyclic bending are experimentally and theoretically investigated. The experimental moment–curvature relationship exhibits an almost steady loop from the beginning of the first cycle. However, the ovalization–curvature relationship exhibits a symmetrical, increasing, and ratcheting behavior as the number of cycles increases. The six groups of tubes tested have different notch depths, from which two different trends can be observed from the relationship between the controlled curvature and the number of cycles required to ignite buckling. Finite element software ANSYS is used to simulate the moment–curvature and ovalization–curvature relationships. Additionally, a theoretical model is proposed for simulation of the controlled curvature-number of cycles concerning the initiation of buckling. Simulation results are compared with experimental test data, which shows generally good agreement.
THE EFFECT OF IMPLANTABLE TRANSDUCERS ON MIDDLE EAR TRANSFER FUNCTION — A COMPARATIVE NUMERICAL ANALYSIS
Authors: LIU HOUGUANG , GE SHIRONG , CHENG GANG , YANG JIANHUA , RAO ZHUSHI , HUANG XINSHENG
Published: June 2015

Several types of middle ear implants (MEIs) have been invented as an alternative to conventional hearing aids for the rehabilitation of sensorineural hearing loss. Temporal bone and clinical studies have shown that the implantation of MEIs’ transducers influences middle ear transfer function. But there is little comparative data available about these influences. We conducted comparative studies on the influences of three principal types of MEI transducers in respect to their attachment points on the ossicular chain. To aid the investigation, a human middle ear finite element model was constructed. The model was built based on a complete set of micro-computerized tomography section images of a human ear by reverse engineering technology. The validity of the developed model was verified by comparing the motions obtained by this model with published experimental measurements on human temporal bones. The results show that the eardrum driving transducer (EDT) and the floating mass transducer (FMT) decrease stapes displacement prominently at high frequencies. The greater these transducers’ mass, the smaller is the displacement of the stapes footplate. In contrast, the incus body driving transducer (IBDT) decreases stapes displacement severely at low frequencies, and its adverse effect on residual hearing increases with increasing stiffness of the IBDT’s driving rod.
Numerical Simulation on Tensile Failure of Rock-Like Heterogeneous Material Using a Modified SPH Method
Authors: Wang Qiusheng , Ma Guowei , Wang X. J.
Published: June 2015

A modified smoothed particle hydrodynamics (SPH) method is applied to simulate the dynamic tensile failure of rock-like heterogeneous materials. The material heterogeneities are represented by different mechanical properties with a Weibull distribution at different particles over the specimen. An elasto-plastic-damage model is adopted to simulate material failure. Numerical simulations are performed for three specimens with different degrees of heterogeneity under quasi-static and dynamic loading conditions, respectively. The effects of strength criterion coefficient [Formula: see text] on the predicted tensile strength are also discussed. Results show that the material heterogeneity has significant effect on the dynamic tensile failure, especially at a higher strain rate loading condition. At a lower strain rate, the failure mode of heterogeneous material is very much similar to that of homogeneous materials. At a higher strain rate, plenty of micro cracks occur forming a failure band in the tension zones. Moreover, the value of strength criterion coefficient [Formula: see text] has a considerable influence on the tensile strength under a higher loading rate.
ORGANISATIONAL AND INDIVIDUAL UNLEARNING IN IDENTIFICATION AND EVALUATION OF TECHNOLOGIES
Authors: SCHEINER CHRISTIAN W. , BACCARELLA CHRISTIAN V. , FELLER NINA , VOIGT KAI-INGO , BESSANT JOHN
Published: June 2015

The ability of an organisation to recognise and evaluate technologically relevant information can be impeded by outdated processes, structures and knowledge. Organisations need therefore a capacity for “intended memory loss”, which has been labelled as unlearning. Although a number of scholars have examined unlearning, research is still only beginning to understand unlearning especially in the area of technology identification and evaluation. The goal of this study is therefore to examine unlearning on an organisational and individual level in this context. Unlearning on an organisational level comprises team composition strategies and directives as well as the implementation of unlearning mechanisms. On an individual level, unlearning highlights cognitive prototypes which exert an influence on the perception of technologies and their evaluation. A qualitative approach has been chosen to examine those aspects, in which technological gatekeepers serve as sample subjects. Technological gatekeepers take a crucial role in the technology identification and evaluation as decision makers and due to their influence on organisational structures and processes. The results of this study suggest that unlearning plays currently only a minor role on an organisational and individual level, which is mainly caused by existing rigidities and in the missing understanding of the necessity to unlearn.
Lifting newforms to vector-valued modular forms for the Weil representation
Authors: Schwagenscheidt Markus , Völz Fabian
Published: June 2015

Given a discriminant form D of level N, there is a natural lifting which maps elliptic modular forms of level N to vector-valued modular forms for the Weil representation associated to D. We show that in some cases the zero component of a lifting of a newform f is just a scalar multiple of f. In order to do so, we split the lifting map into certain partial liftings corresponding to the prime powers exactly dividing N and then proceed to compute the zero components of these partial maps explicitly. As an application, we show that the L-function L𝒜(f, s) of a newform f and an ideal class 𝒜 as defined by Gross and Zagier can be written as a certain L-series of the lifting of f.
Medical images classification for skin cancer using quantitative image features with optical coherence tomography
Authors: Gao Wei , Zakharov Valery P. , Myakinin Oleg O. , Bratchenko Ivan A. , Artemyev Dmitry N. , Kornilin Dmitry V.
Published: June 2015

Optical coherence tomography (OCT) is employed in the diagnosis of skin cancer. Particularly, quantitative image features extracted from OCT images might be used as indicators to classify the skin tumors. In the present paper, we investigated intensity-based, texture-based and fractal-based features for automatically classifying the melanomas, basal cell carcinomas and pigment nevi. Generalized estimating equations were used to test for differences between the skin tumors. A modified p value of [Formula: see text][Formula: see text]0.001 was considered statistically significant. Significant increase of mean and median of intensity and significant decrease of mean and median of absolute gradient were observed in basal cell carcinomas and pigment nevi as compared with melanomas. Significant decrease of contrast, entropy and fractal dimension was also observed in basal cell carcinomas and pigment nevi as compared with melanomas. Our results suggest that the selected quantitative image features of OCT images could provide useful information to differentiate basal cell carcinomas and pigment nevi from the melanomas. Further research is warranted to determine how this approach may be used to improve the classification of skin tumors.
The New Aid Paradigm: A Case of Policy Incoherence
Authors: Dijkstra Geske
Published: June 2015

From around 2000 onwards, donors and recipient governments embarked upon a new aid paradigm. The most important elements include increased selectivity in the aid allocation, more ownership of recipient countries based on nationally elaborated Poverty Reduction Strategy Papers (PRSPs), and more donor alignment and harmonization via programme-based approaches such as budget support. The paper assesses the theoretical merits of this new paradigm, identifying some contradictions and limitations, and then examines its implementation over the past decade and its results. The empirical literature largely confirms the earlier identified weaknesses and limitations. The paper concludes with some suggestions for improving aid practices.
Demystifying Dutch Disease
Authors: Kojo Naoko C.
Published: June 2015

This paper examines the theory of Dutch disease and its implications for practical policy questions. Dutch disease is a term that is well-known to economists and development practitioners. But it is also a concept that is often conflated with "resource curse" and misinterpreted as a "disease" that necessarily causes adverse impacts on the economy. The paper points out that many of the seemingly well-established arguments in this field are not necessarily grounded in theory or empirical evidence. Great care is needed in diagnosing Dutch disease and formulating policy prescriptions based on the theoretical framework, given the restrictive assumptions that may not be fully applicable and the limited relevance to today's inextricably intertwined trade flows.
DONOR CHARACTERISTICS AND THE ALLOCATION OF AID TO CLIMATE MITIGATION FINANCE
Authors: HALIMANJAYA AIDY , PAPYRAKIS ELISSAIOS
Published: June 2015

We make use of a panel dataset of 22 donor countries from 1998 to 2009 to examine the links between donor characteristics and the share of overseas development assistance allocated to climate mitigation finance. We find that donors with a larger green domestic budget tend to allocate a smaller portion of overseas aid to mitigation finance (possibly as a result of a competing interest between spending on domestic environmental projects and international climate projects). The opposite holds for donor countries with better institutions (governance) that have ratified the Kyoto Protocol. We also find important discrepancies when comparing the effects of donor characteristics on committed versus disbursed mitigation finance (as a share of aid). For the latter, only commitment to the Kyoto Protocol appears to be of high statistical significance.