bluuebunny/crossref_metadata_2025 huggingface dataset:
River Pollution
Authors: Wohl Ellen
Published: September 2014

People who are not researchers are most likely to intersect environmental science in the context of protecting or restoring a place or species about which they are concerned, or in the context of pollution—trying to understand the sources and effects of contaminants, or trying to prevent or remediate environmental contamination. The works in this entry address pollutants affecting river ecosystems, including the people who live within or use resources from those ecosystems. Pollution is commonly subdivided based on the primary medium affected by contamination, creating categories such as air pollution, soil pollution, freshwater pollution, groundwater pollution, or marine pollution. In reality, of course, all of these media are intimately connected. Atmospheric deposition of contaminants pollutes soil and water bodies. Contaminated groundwater seeps into rivers, and contaminated rivers recharge groundwater aquifers. Fluxes of water, sediment, solutes, and even organisms carrying contaminants within their tissues create vectors to disperse pollutants. This is one of the great challenges to understanding and mitigating pollution: the contaminant is seldom an inert substance that stays in one place. Another great challenge is that there are many different types of contaminants, including human and animal wastes such as sewage or intestinal bacteria, excess nutrients, heavy metals, petroleum products, radioactive isotopes, and an enormous array of synthetic chemicals such as pesticides and personal care products. Each type of contaminant can disperse through environmental media, combining with other chemical compounds to form metabolites that may have different levels of toxicity for organisms or different dispersal mechanisms than the original contaminant. Yet another challenge in understanding and managing pollutants is that a substance that is harmful to one type of organism may not cause harm to another type of organism, but detailed knowledge of how individual pollutants affect the spectrum of living organisms is almost never available. Consequently, the environmental standards set by government agencies for maximum permissible levels of contaminants are based on very limited knowledge and are likely to be inadequate. Most of the standards are also based on acute effects that show up very quickly. Contaminant levels below permissible standards can cause chronic effects—subtle but pervasive changes that eventually degrade the health of individual organisms and populations. Some chronic effects result from bioaccumulation, as an organism accumulates contaminants within its tissues over the course of its life, and biomagnification, as organisms pass on their accumulated doses to predators or scavengers.
Proprietary Colonies
Authors: Roper L. H.
Published: September 2014

The constitution of early modern western European polities determined that “public” activities were customarily undertaken by “private” persons or entities pursuant to governmental charters that set out their powers, rights, and responsibilities in exchange for a cut of the revenue that their endeavors generated. This arrangement was necessitated by the habitual fiscal woes and limited bureaucratic capacity of governments along with their fitful interest in overseas affairs, especially colonization. Thus, any investigation into the history of European overseas interests must consider the activities of these recipients. Those interested in the history of European polities (“state formation”) may also be interested in this system and how it governed overseas imperial history even to the dawn of the twentieth century. The concept of “proprietary colonies” derives directly from feudal devices by which medieval monarchies dealt with the problems of distance and government by creating ligaments that connected remote localities to the governmental center via the delegation of the administration and defense of remote parts of their realms to prominent persons on the ground, such as the bishops of Durham in England or the encomenderos in Castile. The adaptation of this scenario to govern overseas ventures was natural, given the even greater distances entailed in overseas colonization and trade. Sometimes, the recipients of chartered rights and responsibilities delegated those rights and responsibilities, in turn, to others, usually resident in the particular colony concerned. The term “proprietary colonies” as used in this article includes “proprietorships,” colonies founded by individuals or partners, which constituted one form of this vehicle, as well as the operations of the colonial agents who oversaw substantial tracts of territory, and by joint-stock corporations that founded and governed colonies in Asia and Africa as well as America. This article contains references to work on proprietary colonies in general and to histories of particular colonies in the Americas. Although these latter titles tend to omit discussion of proprietorships as such, they do offer treatments of the formation of these colonies, the intent and plans of proprietors, and their relationships with their colonists as well as with competing interests. Recent focus on the involvement of women in the history of these endeavors has been an especially welcome addition to the historiography. The enduring popularity of these devices for contemporaries is apparent from their appearance in the history of an array of colonies set forth under Particular Proprietary Colonies.
Domestic Slave Trades in the Americas
Authors: Tadman Michael
Published: September 2014

Through their power to tear families apart, domestic slave trades (also called internal slave trades) brought awful extra layers of suffering to add to the emotional and physical burdens of enslavement. These brutal trades were crucial for the expansion of some major slave economies, most notably the booming 19th-century phases of slavery in the United States and Brazil. In these coerced migrations, enslaved people were sometimes transported by sea, river, or railroad, but much more often they were chained together in coffles and were marched great distances to regions where labor demand and slave prices were especially high. Major urban centers played important roles in these trades, but the grassroots of villages and plantations were far more important both in the buying and in the selling phases of the trade. The domestic trades with which this article is concerned relied on one crucial factor: regional differences in the price of slaves. For a large-scale traffic to be sustained, however, a second factor was of great importance too: slave-exporting areas usually had a naturally increasing population that produced a surplus of enslaved people for distant markets. The dominance of sugar plantations in many slave regimes in the Americas (and the link of sugar planting to natural decrease) limited the potential for domestic slave traffics in many parts of the Americas. The domestic trades that have been most researched share two key features. First, the slave society had ended, or virtually ended, its involvement in the African slave trade, and, second, an antislavery movement was active in drawing public attention to the pain inflicted by these domestic trades. The domestic trade was most prominent in North America from 1807 (the abolition of the African trade) to 1865 (the abolition of US slavery), in Brazil from 1850 (the ending of African importation) to 1888 (the ending of slavery), and in the British Caribbean from 1807 (again, the abolition of the African trade) to the abolition of slavery in 1833. The skew of this article toward North America reflects the far more extensive scholarship on that region as well as fundamental demographic factors that worked against trading in many other areas. For the South American and Caribbean slave regimes generally, however, work on areas of natural increase and decrease, as well as on regional slave prices, could open up new knowledge on domestic trades and their significance. The local selling of enslaved people within neighborhoods existed throughout all slave regimes, but local sales are not central to this article. The long-distance redistribution of newly imported Africans is beyond the scope of the article. It should be noted that some studies have important things to say about several key issues, and they are therefore cited more than once.
Erving Goffman
Authors: Leeds-Hurwitz Wendy
Published: September 2014

Erving Goffman (1922–1982) was the sociologist who first proposed investigating the “interaction order,” that is, the organization underlying relationships in everyday life, as a serious topic. He was a social theorist of large ideas which have served as the basis of studies of language and social interaction ever since. His explanations of identity, multiple selves, and social roles have shaped current discussion on these subjects across disciplines, but especially in sociology, communication, and psychology. While at the University of California, Berkeley, he taught Emanuel Schegloff and Harvey Sacks, thus contributing to the development of conversation analysis, though that was not his own focus and he sometimes critiqued the ways in which it developed. At Berkeley he was a colleague of John Gumperz, and thus part of early discussions that led to interactional sociolinguistics. Both at Berkeley and later at the University of Pennsylvania, he was a colleague of Dell Hymes, and thus part of the development of the ethnography of communication. Goffman is often classified as a symbolic interactionist, but he rejected this label (as he rejected all labels). His concerns were uncommonly broad: he wanted to understand human interaction, starting with mundane, everyday behavior, most frequently focusing on how strangers interact. His influence has been felt across a wide array of topics within communication, ranging from health to organizational, from legal to political, from analysis of face-to-face interaction to media and performance studies. Decades after his publications appeared, they have become standard references. Within communication, he is often best known for his dramaturgical approach, but the analogy of life as theater was only one of the many fruitful ideas he proposed.
The City in Film
Authors: Wojcik Pamela Robertson
Published: September 2014

Cinema and the city are historically interrelated. The rise of cinema followed on the heels of urbanization and industrialization, and early cinema production and exhibition was largely urban. Moreover, the city has proved to be a rich and diverse cinematic setting and subject. Early cinema recorded scenes of urban life in actuality, melodrama, and City Symphonies. Gangster films, German expressionism, and Film Noir rendered an urban underworld; the musical and romantic comedy produced a more utopian view of the city; and art cinema rendered the everyday reality of urban life. Recent films imagine dystopic post-urban settings and, alternately, megacities populated by superheroes. The relationship between the cinema and the city can be examined in numerous ways. In part, cinema provides an urban archive or memory bank that reflects changes in the urban landscape. At the same time, cinema serves to produce the city, both literally—in the way that film production shapes Los Angeles, Mumbai, Rome, Hong Kong, and other centers of production—and also by producing an imaginary urbanism through the construction of both fantasy urban spaces and ideas and ideals of the city. Theorists suggest that there is an inherent urbanism to cinema. Kracauer 1997 (cited under General Overviews) claims the city, and especially the street, as exemplary and essential cinematic space, attuned to the experience of contingency, flow, and indeterminacy linked to modernity. Hansen 1999 (also cited under General Overviews) suggests that cinema worked as a kind of vernacular modernism to articulate and mediate the experience of modernity—and especially urbanization. More recently, attention to theories of space and urbanism across the academy have generated broad interest in cinematic urbanism. Much of this work brings film scholars into conversation with urban planners, geographers, and architects. Of course neither cinema nor the city is singular. Thus work on the city and film must attend to multiple global cities at different historical periods and, furthermore, consider that cinema produces multiple versions of even a single city, such as New York, as different narratives, genres, studios, directors, and individual films will each produce a different city. Some books and articles tangentially examine films set in cities. This article will include only those texts that have the urban sphere as a primary focus of their investigation.
European Jewish Sociology
Authors: Morris-Reich Amos
Published: September 2014

There is wide consensus among historians that European Jewish sociology only comes into being with its institutionalization as a field in the first decade of the 20th century with the establishment of a society, an academic journal, and an office dedicated to the subject. While this institutionalization is recognized to have been advanced primarily by Arthur Ruppin, there is growing agreement among historians that several authors working more or less parallel to Ruppin greatly contributed to the emergence of the field in Italy, Russia, Great Britain, and Germany and to the emergence of a vast body of research in German, Russian, Yiddish, and Hebrew. Although the boundaries between European sociological discourses (e.g., Emile Durkheim and Marcel Mauss in France or Georg Simmel in Germany) and Jewish sociology are not always stable, scholars widely assent that European Jewish sociology denotes the study of contemporary Jewry with the tools of modern social science. Historians have also documented the unstable boundaries between European and American Jewish sociology (e.g., Max Weinreich, Maurice Fishberg, or Joseph Jacobs). Scholars also agree that similarly to broader trends in Europe connected to the emergence of nationalism, its general context was that of attempts to employ scientific tools for the rationalization of society, and more specifically for finding solutions to social tensions and problems. As such, its generators viewed its primary aim to study and understand the condition and future tendencies of Jews in modern non-Jewish-majority societies. In particular, this included degrees of assimilation of Jews into non-Jewish societies and the measurement of anti-Semitic hostility toward Jews. In comparison with other branches of sociology, Jewish sociology tended to focus on empirical questions and showed less interest in general theoretical or methodological concerns. With Ruppin’s immigration to Palestine in 1908 and his position as a professor of sociology (1926–1943) at the newly established Hebrew University, the center of European Jewish sociology shifted to Palestine. Studies in the field were continued by some of Ruppin’s prominent former students.
Prognostic Scoring Models for Patients Undergoing Sorafenib Treatment for Advanced Stage Hepatocellular Carcinoma in Real-Life Practice
Authors: Choi Gwang Hyeon , Han Seungbong , Shim Ju Hyun , Ryu Min-Hee , Ryoo Baek-Yeol , Kang Yoon-Koo , Kim Kang Mo , Lim Young-Suk , Lee Han Chu
Published: September 2014

Background:

The purpose of this study was to build prognostic models capable of estimating the outcomes of individual sorafenib-treated advanced stage hepatocellular carcinoma (HCC) patients based on specific patient and tumor factors.

Methods:

A parametric model for time-to-event data was used to construct scoring systems based on the intent-to-treat data set from 480 sorafenib-treated patients with advanced stage HCC: 356 for derivation and 124 for validation. Clinical parameters included in the models were based on importance variable scores generated by a random forest approach and bootstrap resampling. The model’s accuracy was internally and externally assessed using the time-dependent C-index of discrimination and a Hosmer-Lemeshow type test for calibration.

Results:

The models generated for time-to-progression and overall survival based on Child-Pugh score, serum α-fetoprotein, tumor morphology, and vascular invasion and/or extrahepatic involvement had good calibration and discrimination abilities, with C-indexes of 0.669 (3 mo progression) and 0.809 (6 mo survival), respectively. External validation results also showed that these models performed well in terms of goodness-of-fit and discrimination (C-index: 0.746 for 3 mo progression and 0.875 for 6 mo survival). Receiver operating characteristic curve analysis in the validation patients indicated that these models have better predictive power than Child-Pugh scores (C-index: 0.686 for 3 mo progression and 0.777 for 6 mo survival).

Conclusions:

The prognostic tools developed to quantify the potential outcomes for progression and survival expected from sorafenib treatment can serve as useful clinical aids in personalized decision making regarding treatment in advanced stage HCC patients.
Hepatocellular Carcinoma Management in Nonalcoholic Fatty Liver Disease Patients
Authors: Kikuchi Luciana , Oliveira Claudia P. , Alvares-da-Silva Mario R. , Tani Claudia M. , Diniz Marcio A. , Stefano Jose T. , Chagas Aline L. , Alencar Regiane S.S.M. , Vezozzo Denise C.P. , Santos Gilmar R. , Campos Priscila B. , Alves Venancio AF. , Ratziu Vlad , Carrilho Flair J.
Published: September 2014

Background/Aims:

Nonalcoholic fatty liver disease (NAFLD) has emerged as an important cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma (HCC). The Barcelona Clinic Liver Cancer (BCLC) system is the preferred staging system to evaluate patients with HCC and links prognosis assessment with treatment recommendation. The aim of this retrospective study was to evaluate whether the BCLC staging system and its treatment algorithm are suitable for patients with HCC arising from NAFLD.

Methods:

Forty-two patients with HCC related to either to NAFLD or cryptogenic cirrhosis were retrieved retrospectively from 2 centers in Brazil. Patients were classified according to BCLC staging system. If the proposed HCC therapy could not be applied, the case was considered to represent deviations from the recommended BCLC guideline. Causes of treatment deviations were investigated.

Results:

There were 4 patients without evidence of cirrhosis according to liver biopsy and/or clinical evaluation. One (2%), 21 (50%), 10 (24%), 5 (12%), and 5 patients (12%) were classified initially to the very early (0), early (A), intermediate (B), advanced (C), and terminal (D) BCLC stages, respectively. Thirty-five patients (83%) were treated according to BCLC recommendations. There were 3 cases (of 5) of protocol deviation in BCLC C patients. The 1- and 2-year overall survival rates were 81% and 66%, respectively.

Conclusions:

The BCLC system is applied in most cases of NAFLD-related HCC cases. Deviation of BCLC is found more frequently in BCLC C stage patients.
Model-based hierarchical reinforcement learning and human action control
Authors: Botvinick Matthew , Weinstein Ari
Published: September 2014

Recent work has reawakened interest in goal-directed or ‘model-based’ choice, where decisions are based on prospective evaluation of potential action outcomes. Concurrently, there has been growing attention to the role of hierarchy in decision-making and action control. We focus here on the intersection between these two areas of interest, considering the topic of
hierarchical model-based control.
To characterize this form of action control, we draw on the computational framework of hierarchical reinforcement learning, using this to interpret recent empirical findings. The resulting picture reveals how hierarchical model-based mechanisms might play a special and pivotal role in human decision-making, dramatically extending the scope and complexity of human behaviour.
The anatomy of choice: dopamine and decision-making
Authors: Friston Karl , Schwartenbeck Philipp , FitzGerald Thomas , Moutoussis Michael , Behrens Timothy , Dolan Raymond J.
Published: September 2014

This paper considers goal-directed decision-making in terms of embodied or active inference. We associate bounded rationality with approximate Bayesian inference that optimizes a free energy bound on model evidence. Several constructs such as expected utility, exploration or novelty bonuses, softmax choice rules and optimism bias emerge as natural consequences of free energy minimization. Previous accounts of active inference have focused on
predictive coding
. In this paper, we consider
variational Bayes
as a scheme that the brain might use for approximate Bayesian inference. This scheme provides formal constraints on the computational anatomy of inference and action, which appear to be remarkably consistent with neuroanatomy. Active inference contextualizes optimal decision theory within embodied inference, where goals become prior beliefs. For example, expected utility theory emerges as a special case of free energy minimization, where the
sensitivity
or inverse temperature (associated with softmax functions and quantal response equilibria) has a unique and Bayes-optimal solution. Crucially, this sensitivity corresponds to the
precision
of beliefs about behaviour. The changes in precision during variational updates are remarkably reminiscent of empirical dopaminergic responses—and they may provide a new perspective on the role of dopamine in assimilating reward prediction errors to optimize decision-making.
The why, what, where, when and how of goal-directed choice: neuronal and computational principles
Authors: Verschure Paul F. M. J. , Pennartz Cyriel M. A. , Pezzulo Giovanni
Published: September 2014

The central problems that goal-directed animals must solve are: ‘Whatdo I need andWhy,WhereandWhencan this be obtained, andHowdo I get it?' or the H4W problem. Here, we elucidate the principles underlying the neuronal solutions to H4W using a combination of neurobiological and neurorobotic approaches. First, we analyse H4W from a system-level perspective by mapping its objectives onto theDistributed Adaptive Controlembodied cognitive architecture which sees the generation of adaptive action in the real world as the primary task of the brain rather than optimally solving abstract problems. We next map this functional decomposition to the architecture of the rodent brain to test its consistency. Following this approach, we propose that the mammalian brain solves the H4W problem on the basis of multiple kinds of outcome predictions, integrating central representations of needs and drives (e.g. hypothalamus), valence (e.g. amygdala), world, self and task state spaces (e.g. neocortex, hippocampus and prefrontal cortex, respectively) combined with multi-modal selection (e.g. basal ganglia). In our analysis, goal-directed behaviour results from a well-structured architecture in which goals are bootstrapped on the basis of predefined needs, valence and multiple learning, memory and planning mechanisms rather than being generated by a singular computation.
Virtual bargaining: a theory of social decision-making
Authors: Misyak Jennifer B. , Chater Nick
Published: September 2014

An essential element of goal-directed decision-making in social contexts is that agents' actions may be mutually interdependent. However, the most well-developed approaches to such strategic interactions, based on the Nash equilibrium concept in game theory, are sometimes too broad and at other times ‘overlook’ good solutions to fundamental social dilemmas and coordination problems. The authors propose a new theory of social decision-making—virtual bargaining—in which individuals decide among a set of moves on the basis of what they would agree to do if they could openly bargain. The core principles of a formal account are outlined (vis-à-vis the notions of ‘feasible agreement’ and explicit negotiation) and further illustrated with the introduction of a new game, dubbed the ‘Boobytrap game’ (a modification on the canonical Prisoner's Dilemma paradigm). In the first empirical data of how individuals play the Boobytrap game, participants' experimental choices accord well with a virtual bargaining perspective, but do not match predictions from a standard Nash account. Alternative frameworks are discussed, with specific empirical tests between these and virtual bargaining identified as future research directions. Lastly, it is proposed that virtual bargaining underpins a vast range of human activities, from social decision-making to joint action and communication.
Faucicola mancuniensis gen. nov., sp. nov., isolated from the human oropharynx
Authors: Humphreys Gavin J. , Oates Angela , Ledder Ruth G. , McBain Andrew J.
Published: September 2014

An aerobic, Gram-stain-negative, non-motile coccus, designated strain GVCNT2T, was isolated from the tonsils of a healthy adult female. Cells were oxidase- and catalase-positive, positive for the production of esterase (C4), esterase lipase (C8) and leucine arylamidase, and weakly positive for naphthol-AS-BI-phosphohydrolase and alkaline phosphatase. Cells were also capable of hydrolysing DNA. Growth was observed at 20–37 °C and in the presence of up to 1.5 % NaCl. Phylogenetic analysis of near full-length 16S rRNA gene sequences indicated that the strain exhibited closest sequence similarity to

Moraxella boevrei

ATCC 700022T (94.68 %) and an uncultured, unspeciated bacterial clone (strain S12-08; 99 %). The major fatty acids were C18 : 1ω9c, C18 : 0, C16 : 0 and C16 : 1ω6c/C16 : 1ω7c. The DNA G+C content of strain GVCNT2T was 40.7 mol%. The major respiratory quinone identified was Q-8. Strain GVCNT2T exhibited a comparable phenotypic profile to other members of the genus

Moraxella

but could be distinguished based on its ability to produce acid (weakly) from d-glucose, melibiose, l-arabinose and rhamnose and on its ability to hydrolyse DNA. On the basis of phenotypic and phylogenetic differences from other members of the family

Moraxellaceae

, strain GVCNT2T is considered to represent a novel species of a new genus, for which the name Faucicola mancuniensis gen. nov., sp. nov. is proposed. The type strain of Faucicola mancuniensis is GVCNT2T ( = DSM 28411T = NCIMB 14946T).
U2AF1 mutations alter splice site recognition in hematological malignancies
Authors: Ilagan Janine O. , Ramakrishnan Aravind , Hayes Brian , Murphy Michele E. , Zebari Ahmad S. , Bradley Philip , Bradley Robert K.
Published: September 2014

Whole-exome sequencing studies have identified common mutations affecting genes encoding components of the RNA splicing machinery in hematological malignancies. Here, we sought to determine how mutations affecting the 3′ splice site recognition factor U2AF1 alter its normal role in RNA splicing. We find that U2AF1 mutations influence the similarity of splicing programs in leukemias, but do not give rise to widespread splicing failure. U2AF1 mutations cause differential splicing of hundreds of genes, affecting biological pathways such as DNA methylation (DNMT3B), X chromosome inactivation (H2AFY), the DNA damage response (ATR, FANCA), and apoptosis (CASP8). We show that U2AF1 mutations alter the preferred 3′ splice site motif in patients, in cell culture, and in vitro. Mutations affecting the first and second zinc fingers give rise to different alterations in splice site preference and largely distinct downstream splicing programs. These allele-specific effects are consistent with a computationally predicted model of U2AF1 in complex with RNA. Our findings suggest that U2AF1 mutations contribute to pathogenesis by causing quantitative changes in splicing that affect diverse cellular pathways, and give insight into the normal function of U2AF1’s zinc finger domains.
Crystal structure of 1-(2-chloroacetyl)-2,6-bis(4-fluorophenyl)-3,3-dimethylpiperidin-4-one
Authors: Jothivel S. , Kotoky Jibon , Kabilan S.
Published: September 2014

In the title molecule, C21H20ClF2NO2, the piperidine ring adopts a slightly distorted boat conformation. The two benzene rings form a dihedral angle of 87.43 (1)°. A weak intramolecular C—H...π interaction is observed. In the crystal, weak C—H...O hydrogen bonds and weak C—H...π interactions connect the molecules, forming a three-dimensional network.
Crystal structure of (5R)-5-[(1S)-1,2-dihydroxyethyl]-4-methoxy-3-phenyl-2,5-dihydrofuran-2-one
Authors: Kote Santosh R. , Thopate Shankar R. , Gupta Sushil K. , Butcher Ray J.
Published: September 2014

In the title compound, C13H14O5, the furan ring is essentially planar [maximum deviation = 0.031 (3) Å] with a stereogenic center (R) at thesp3hybridized C atom. The C atom bearing the dihydroxy ethyl group isS. The absolute configuration is based on the precursor in the synthesis. The two O—H groups are in ananticonformation with respect to each other. The mean plane of the furanone group is twisted by 8.2 (4)° from that of the phenyl ring. In the crystal, molecules are linked by O—H...O hydrogen bonds involving furanone C=O groups and symmetry-related hydroxy groups, forming a two-dimensional network parallel to (001). Weak C—H...O hydrogen bonds are observed within the two-dimensional network.
Characteristics of a tapered undulator for the X-ray absorption fine-structure technique at PLS-II
Authors: Sung Nark-Eon , Lee Ik-Jae , Jeong Sung-hoon , Kang Seen-Woong
Published: September 2014

An in-vacuum undulator (IVU) with a tapered configuration was installed in the 8C nanoprobe/XAFS beamlime (BL8C) of the Pohang Light Source in Korea for hard X-ray nanoprobe and X-ray absorption fine-structure (XAFS) experiments. It has been operated in planar mode for the nanoprobe experiments, while gap-scan and tapered modes have been used alternatively for XAFS experiments. To examine the features of the BL8C IVU for XAFS experiments, spectral distributions were obtained theoretically and experimentally as functions of the gap and gap taper. Beam profiles at a cross section of the X-ray beam were acquired using a slit to visualize the intensity distributions which depend on the gap, degree of tapering and harmonic energies. To demonstrate the effect of tapering around the lower limit of the third-harmonic energy, VK-edge XAFS spectra were obtained in each mode. Owing to the large X-ray intensity variation around this energy, XAFS spectra of the planar and gap-scan modes show considerable spectral distortions in comparison with the tapered mode. This indicates that the tapered mode, owing to the smooth X-ray intensity profile at the expense of the highest and most stable intensity, can be an alternative for XAFS experiments where the gap-scan mode gives a considerable intensity variation; it is also suitable for quick-XAFS scanning.
Radiation dose and image quality inK-edge subtraction computed tomography of lungin vivo
Authors: Strengell S. , Keyriläinen J. , Suortti P. , Bayat S. , Sovijärvi A. R. A. , Porra L.
Published: September 2014

K-edge subtraction computed tomography (KES-CT) allows simultaneous imaging of both structural features and regional distribution of contrast elements inside an organ. Using this technique, regional lung ventilation and blood volume distributions can be measured experimentallyin vivo. In order for this imaging technology to be applicable in humans, it is crucial to minimize exposure to ionizing radiation with little compromise in image quality. The goal of this study was to assess the changes in signal-to-noise ratio (SNR) of KES-CT lung images as a function of radiation dose. The experiments were performed in anesthetized and ventilated rabbits using inhaled xenon gas in O2at two concentrations: 20% and 70%. Radiation dose, defined as air kerma (Ka), was measured free-in-air and in a 16 cm polymethyl methacrylate phantom with a cylindrical ionization chamber. The dose free-in-air was varied from 2.7 mGy to 8.0 Gy. SNR in the images of xenon in air spaces was above the Rose criterion (SNR > 5) whenKawas over 400 mGy with 20% xenon, and over 40 mGy with 70% xenon. Although in human thorax attenuation is higher, based on these findings it is estimated that, by optimizing the imaging sequence and reconstruction algorithms, the radiation dose could be further reduced to clinically acceptable levels.
First experimental charge density study using a Bruker CMOS-type PHOTON 100 detector: the case of ammonium tetraoxalate dihydrate
Authors: Jarzembska Katarzyna N. , Kamiński Radosław , Dobrzycki Łukasz , Cyrański Michał K.
Published: September 2014

The aim of this study was to test the applicability of a Bruker AXS CMOS-type PHOTON 100 detector for the purpose of a fine charge density quality data collection. A complex crystal containing oxalic acid, ammonium oxalate and two water molecules was chosen as a test case. The data was collected up to a resolution of 1.31 Å−1with high completeness (89.1%;Rmrg= 0.0274). The multipolar refinement and subsequent quantum theory of atoms in molecules (QTAIM) analysis resulted in a comprehensive description of the charge density distribution in the crystal studied. The residual density maps are flat and almost featureless. It was possible to derive reliable information on intermolecular interactions to model the anharmonic motion of a water molecule, and also to observe the fine details of the charge density distribution, such as polarization on O and H atoms involved in the strongest hydrogen bonds. When compared with our previous statistical study on oxalic acid data collected with the aid of CCD cameras, the complementary metal-oxide semiconductor (CMOS) detector can certainly be classified as a promising alternative in advanced X-ray diffraction studies.
Mackay icosahedron explaining orientation relationship of dispersoids in aluminium alloys
Authors: Muggerud Astrid Marie F. , Li Yanjun , Holmestad Randi , Andersen Sigmund J.
Published: September 2014

The orientation relations (ORs) of the cubic icosahedral quasicrystal approximant phase α-Al(Fe,Mn)Si have been studied after low temperature annealing of a 3xxx wrought aluminium alloy by transmission electron microscopy. From diffraction studies it was verified that the most commonly observed OR for the α-Al(Fe,Mn)Si dispersoids is [1\bar 11]α // [1\bar 11]Al, (5\bar 2\bar 7)α // (011)Al. This orientation could be explained by assuming that the internal Mackay icosahedron (MI) in the α-phase has a fixed orientation in relation to Al, similar to that of the icosahedral quasi-crystals existing in this alloy system. It is shown that mirroring of the normal-to-high-symmetry icosahedral directions of the MI explains the alternative orientations, which are therefore likely to be caused by twinning of the fixed MI. Only one exception was found, which was related to the Bergman icosahedron internal to the T-phase of the Al–Mg–Zn system.
Two-dimensionally stacked heterometallic layers hosting a discrete chair dodecameric ring of water clusters: synthesis and structural study
Authors: Kenfack Tsobnang Patrice , Wenger Emmanuel , Biache Coralie , Lambi Ngolui John , Ponou Siméon , Dahaoui Slimane , Lecomte Claude
Published: September 2014

The stacked two-dimensional supramolecular compoundcatena-{Co(amp)3Cr(ox)3·6H2O} (amp = 2-picolylamine, ox = oxalate) has been synthesized from the bimolecular approach using hydrogen bonds. It is built from layers in which both Co(amp)3+(D) and Cr(ox)3−(A) ions are bonded in a repeatingDADADA… pattern along theaandcaxes by multiple hydrogen bonds. These layers host a well resolvedR12 dodecameric discrete ring of water clusters built by six independent molecules located around the2ccentrosymmetric Wyckoff positions of theP21/nspace group in which the compound crystallizes. These clusters are ranged along the [001] direction, occupy 733.5 Å3(22.0%) of the unit cell and have a chair conformationvia12 hydrogen bonds. The water molecules of the cluster are linked with stronger hydrogen bonds than those between the cluster and its host, which explains the single continuous step of the dehydration process of the compound.
One- and two-dimensional CdIIcoordination polymers constructed from 2-(2-methyl-1H-benzimidazol-1-yl)acetate ligands
Authors: Li Qiang , Wang Hui-Ting , Ye Qiong
Published: September 2014

The one- and two-dimensional polymorphic cadmium polycarboxylate coordination polymers,catena-poly[bis[μ2-2-(2-methyl-1H-benzimidazol-1-yl)acetato-κ3N3:O,O′]cadmium(II)], [Cd(C10H9N2O2)2]n, and poly[bis[μ2-2-(2-methyl-1H-benzimidazol-1-yl)acetato-κ3N3:O,O′]cadmium(II)], also [Cd(C10H9N2O2)2]n, were prepared under solvothermal conditions. In each structure, each CdIIatom is coordinated by four O atoms and two N atoms from four different ligands. In the former structure, two crystallographically independent CdIIatoms are located on twofold symmetry axes and doubly bridged in a μ2-N:O,O′-mode by the ligands into correspondingly independent chains that run in the [100] and [010] directions. Chains containing crystallographically related CdIIatoms are linked into sheetsviaπ–π stacking interactions. Sheets containing one of the distinct types of CdIIatom are stacked perpendicular to [001] and alternate with sheets containing the other type of CdIIatom. The second complex is a two-dimensional homometallic CdII(4,4) net structure in which each CdIIatom is singly bridged to four neighbouring CdIIatoms by four ligands also acting in a μ2-N:O,O′-mode. A square-grid network results and the three-dimensional supramolecular framework is completed by π–π stacking interactions between the aromatic ring systems.
Self-initiated expatriates
Authors: Selmer Jan , Lauring Jakob
Published: September 2014

Purpose

– As it has been suggested that adult third-culture kids may be more culturally adaptable than others, they have been labelled “the ideal” expatriates. The purpose of this paper is to explore the adjustment of self-initiated expatriate academics in Hong Kong, comparing adult third-culture kids with adult mono-culture kids.

Design/methodology/approach

– The authors use survey results from 267 self-initiated expatriate academics in Hong Kong.

Findings

– Exploratory results show that adult third-culture kids had a higher extent of general adjustment. No significant results were found in relation to interaction adjustment and job adjustment. The authors also found that recent expatriate experiences generally had a positive association with the adjustment of adult mono-culture kids, but this association only existed in terms of general adjustment for adult third-culture kids.

Originality/value

– Once corroborated by further studies, this exploratory research project may contribute to the understanding of the adjustment of adult third-culture kids as well as the role of experience and multicultural abilities. Few, if any, prior studies, have examined adjustment of this group of self-initiated expatriates.
Parameter identification for a low-density-foam material model using numerical optimisation procedures
Authors: Škrlec Andrej , Klemenc Jernej , Fajdiga Matija
Published: September 2014

Purpose

– In the event of a crash involving a car, its seats, together with their backrests and head supports, ensure the safety of the passengers. The filling material used for such a car seat is normally made of polyurethane foam. To simulate the behaviour of the seat assembly during a crash, the material characteristics of the seat-filling foam should be appropriately modelled. The purpose of this paper is to present a method, with which the proper parameter values of the selected material model for the seat-filling foam can be easily determined.

Design/methodology/approach

– In the study, an experiment with the specimen from seat-filling foam was carried out. The results from this experiment were the basis for the determination of the parameter values of the low-density-foam material model, which is often used in crash-test simulations. Two different numerical optimisation algorithms – a genetic algorithm and a gradient-descent algorithm – were coupled with LS-DYNA explicit simulations to identify the material parameters.

Findings

– The paper provides comparison of two optimisation algorithms and discusses the engineering applicability of the results.

Originality/value

– This paper presents an approach for the identification of the missing parameter values of the highly non-linear material model, if these cannot be easily determined directly from experimental data.
Numerical simulation of initial mixing of marine wastewater discharge from multiport diffusers
Authors: Xue Wanyun , Huai Wenxin , Qian Zhongdong , Yang Zhonghua , Zeng Yuhong
Published: September 2014

Purpose

– The purpose of this paper is to examine the initial mixing of wastewater discharged from submerged outfall diffusers and the influence of port configurations on wastewater distribution based on computational results.

Design/methodology/approach

– Marine wastewater discharges from multiport diffusers are investigated by numerically solving three-dimensional and uncompressible two-phase flow fields. A mixture model simulates this flow and the standard k-e model to resolve flow turbulence; inter-phase interactions were described in terms of relative slip velocity between phases. Computations were performed for two values of the port spacings s/H with different current Froude numbers F.

Findings

– Computational results compared well with previous laboratory measurements. Numerical results reveal that for both the closely spaced (s/H=0.21) and widely spaced (s/H=3.0) ports, the normalized dilution Sn becomes independent of F; further, the length of the near field xn and the spreading layer thickness hn are functions of F. For the closely spaced ports, the wastewater discharge behaves like a line plume, the Coanda effect is obvious, quasi-bifurcation is present, horseshoe structures of the jets in the planes are rapidly produced and then squashed and elongated, and the jet trajectories based on maximum velocity precede those based on maximum concentration. For the widely spaced ports, the wastewater discharge behaves like a point plume, the Coanda effect is not obvious, bifurcation is present, horseshoe structures of the jets in the planes are gradually produced and become ellipses, and the jet trajectories based on maximum velocity are similar to those based on maximum concentration.

Originality/value

– Semi-empirical equations are presented to predict major near field characteristics. These provide guidance for designing multiport diffusers and assessing environmental impact.
A comparative study of the stochastic simulation methods applied in structural health monitoring
Authors: Zhang Yanhui , Yang Wenyu
Published: September 2014

Purpose

– The purpose of this paper is to discuss the characteristics of several stochastic simulation methods applied in computation issue of structure health monitoring (SHM).

Design/methodology/approach

– On the basis of the previous studies, this research focusses on four promising methods: transitional Markov chain Monte Carlo (TMCMC), slice sampling, slice-Metropolis-Hasting (M-H), and TMCMC-slice algorithm. The slice-M-H is the improved slice sampling algorithm, and the TMCMC-slice is the improved TMCMC algorithm. The performances of the parameters samples generated by these four algorithms are evaluated using two examples: one is the numerical example of a cantilever plate; another is the plate experiment simulating one part of the mechanical structure.

Findings

– Both the numerical example and experiment show that, identification accuracy of slice-M-H is higher than that of slice sampling; and the identification accuracy of TMCMC-slice is higher than that of TMCMC. In general, the identification accuracy of the methods based on slice (slice sampling and slice-M-H) is higher than that of the methods based on TMCMC (TMCMC and TMCMC-slice).

Originality/value

– The stochastic simulation methods evaluated in this paper are mainly two categories of representative methods: one introduces the intermediate probability density functions, and another one is the auxiliary variable approach. This paper provides important references about the stochastic simulation methods to solve the ill-conditioned computation issue, which is commonly encountered in SHM.
On a fractional step-splitting scheme for the Cahn-Hilliard equation
Authors: Aderogba A.A. , Chapwanya M. , Djoko J.K.
Published: September 2014

Purpose

– For a partial differential equation with a fourth-order derivative such as the Cahn-Hilliard equation, it is always a challenge to design numerical schemes that can handle the restrictive time step introduced by this higher order term. The purpose of this paper is to employ a fractional splitting method to isolate the convective, the nonlinear second-order and the fourth-order differential terms.

Design/methodology/approach

– The full equation is then solved by consistent schemes for each differential term independently. In addition to validating the second-order accuracy, the authors will demonstrate the efficiency of the proposed method by validating the dissipation of the Ginzberg-Lindau energy and the coarsening properties of the solution.

Findings

– The scheme is second-order accuracy, the authors will demonstrate the efficiency of the proposed method by validating the dissipation of the Ginzberg-Lindau energy and the coarsening properties of the solution.

Originality/value

– The authors believe that this is the first time the equation is handled numerically using the fractional step method. Apart from the fact that the fractional step method substantially reduces computational time, it has the advantage of simplifying a complex process efficiently. This method permits the treatment of each segment of the original equation separately and piece them together, in a way that will be explained shortly, without destroying the properties of the equation.
Elastic wave propagation and time history analysis in FG nanocomposite cylinders reinforced by carbon nanotubes using a hybrid mesh-free method
Authors: Mahmoud Hosseini Seyed
Published: September 2014

Purpose

– The purpose of this paper is to propose a hybrid mesh-free method based on generalized finite difference (GFD) and Newmark finite difference methods to study the elastic wave propagation in functionally graded nanocomposite reinforced by carbon nanotubes (FGNRCN). The presented hybrid mesh-free method is applied for a thick hollow cylinder, which is made of FGNRCN and excited by various mechanical shock loadings.

Design/methodology/approach

– The FG nanocomposite cylinder is assumed to be under shock loading. The elastic wave propagation is obtained and studied for various nonlinear grading patterns and distributions of the aligned carbon nanotubes. The distribution of carbon naotubes in FG nanocomposite are considered to vary as nonlinear function of radius, which varies with various nonlinear grading patterns continuously through radial direction. The effective material properties of functionally graded carbon nanotube are estimated using a micro-mechanical model.

Findings

– The mechanical shock analysis of FGNRCN thick hollow cylinder is carried out and the dynamic behavior of displacement field and the time history of radial displacement are obtained for various grading patterns. An effective hybrid mesh-free method based on GFD and Newmark finite difference methods is presented to calculate the average velocity of elastic wave propagation in FGNRCN. The average velocity of elastic wave propagation is obtained for various grading patterns and various kinds of volume fraction. The effects of some parameters on average velocity of elastic wave propagation are obtained and studied in detail.

Originality/value

– The calculation of elastic radial wave propagation in a FGNRCN thick hollow cylinder is presented using a hybrid mesh-free method. The effects of some parameters on wave propagation such as various grading patterns of distribution of carbon nanotubes are studied in details.