bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear Superposition Operators
Authors: Appell Jürgen , Zabrejko Petr P.
Published: February 2012

This book is a self-contained account of knowledge of the theory of nonlinear superposition operators: a generalization of the notion of functions. The theory developed here is applicable to operators in a wide variety of function spaces, and it is here that the modern theory diverges from classical nonlinear analysis. The purpose of this book is to collect the basic facts about the superposition operator, to present the main ideas which are useful in studying its properties and to provide a comparison of its behaviour in different function spaces. Some applications are also considered, for example to control theory and optimization. Much of the work here has only appeared before in research literature, which itself is catalogued in detail here.
Entropy, Compactness and the Approximation of Operators
Authors: Carl Bernd , Stephani Irmtraud
Published: February 2012

Entropy quantities are connected with the 'degree of compactness' of compact or precompact spaces, and so are appropriate tools for investigating linear and compact operators between Banach spaces. The main intention of this Tract is to study the relations between compactness and other analytical properties, e.g. approximability and eigenvalue sequences, of such operators. The authors present many generalized results, some of which have not appeared in the literature before. In the final chapter, the authors demonstrate that, to a certain extent, the geometry of Banach spaces can also be developed on the basis of operator theory. All mathematicians working in functional analysis and operator theory will welcome this work as a reference or for advanced graduate courses.
History of British Space Science
Authors: Massie Harrie , Robins M. O.
Published: February 2012

This book documents how a complex branch of science was started and encouraged to grow both nationally and internationally, as seen through the eyes of two authors who together played a major role in many of the events that they describe. It traces the beginning and subsequent development of a space science programme for British scientists from the early 1950s to the early 1980s, and gives the scientific, technological and administrative background whilst highlighting some of the outstanding successes of the programme. Cooperation with NASA in the United States is described in some detail, and the part played by Britain in establishing European cooperation in space science is outlined, as is the more modest cooperative programme with Commonwealth countries. This historical account will be of interest to all space scientists, geophysicists and astronomers, as well as to those concerned with the administration and organisation of large, co-operative scientific programmes.
Brethren in Christ
Authors: Grell Ole Peter
Published: February 2012

This groundbreaking book explores the migration of Calvinist refugees in Europe during the Reformation, across a century of persecution, exile and minority existence. Ole Peter Grell follows the fortunes of some of the earliest Reformed merchant families, forced to flee from the Tuscan city of Lucca during the 1560s, through their journey to France during the Wars of Religion to the St Bartholomew Day Massacre and their search for refuge in Sedan. He traces the lives of these interconnected families over three generations as they settled in European cities from Geneva to London, marrying into the diaspora of Reformed merchants. Based on a potent combination of religion, commerce and family networks, these often wealthy merchants and highly skilled craftsmen were amongst the most successful of early modern capitalists. Brethren in Christ shows how this interconnected network, reinforced through marriage and enterprise, forged the backbone of international Calvinism in Reformation Europe.
Process Development in Antibiotic Fermentations
Authors: Calam C. T.
Published: February 2012

Process development in antibiotic fermentation is of microbiological and commercial importance and this book gives a consistent treatment of the area. It is divided into three parts: the first deals with the scientific background to the subject, the second with process development in the laboratory and the third with industrial fermentation plants and pilot plants. The discussion shows how problems change as processes are scaled up and yields increase. The book is written from a practical angle and examples of development work are given to support the background information. It will be particularly useful to students of applied microbiology and to those postgraduate microbiologists who are widening their experience with the development of antibiotic fermentations in relation to the production plant, both as a lecturer and as an industrial consultant and he has made use of his wide knowledge of all these areas in this book.
Finite Ordered Sets
Authors: Caspard Nathalie , Leclerc Bruno , Monjardet Bernard
Published: February 2012

Ordered sets are ubiquitous in mathematics and have significant applications in computer science, statistics, biology and the social sciences. As the first book to deal exclusively with finite ordered sets, this book will be welcomed by graduate students and researchers in all of these areas. Beginning with definitions of key concepts and fundamental results (Dilworth's and Sperner's theorem, interval and semiorders, Galois connection, duality with distributive lattices, coding and dimension theory), the authors then present applications of these structures in fields such as preference modelling and aggregation, operational research and management, cluster and concept analysis, and data mining. Exercises are included at the end of each chapter with helpful hints provided for some of the most difficult examples. The authors also point to further topics of ongoing research.
The Politics of Gender in Victorian Britain
Authors: Griffin Ben
Published: February 2012

This groundbreaking history of Victorian politics, feminism and parliamentary reform challenges traditional assumptions about the development of British democracy and the struggle for women's rights and demonstrates how political activity has been shaped by changes in the history of masculinity. From the second half of the nineteenth century, Britain's all-male parliament began to transform the legal position of women as it reformed laws that had upheld male authority for centuries. To explain these revolutionary changes, Ben Griffin looks beyond the actions of the women's movement alone and shows how the behaviour and ideologies of male politicians were fundamentally shaped by their gender. He argues that changes to women's rights were the result not simply of changing ideas about women but also of changing beliefs about masculinity, religion and the nature of the constitution, and, in doing so, demonstrates how gender inequality can be created and reproduced by the state.
Unknown Mexico
Authors: Lumholtz Carl
Published: February 2012

Carl Lumholtz (1851–1922) was a Norwegian ethnographer and explorer who, soon after publishing an influential study of Australian Aborigines (also reissued in the Cambridge Library Collection), spent five years researching native peoples in Mexico. This two-volume work, published in 1903, describes his expeditions to remote parts of north-west Mexico, inspired by reports about indigenous peoples who lived in cliff dwellings along mountainsides. While in the US in 1890 on a lecture tour, Lumholtz was able to raise sufficient funds for the expedition. He arrived in Mexico City that summer, and after meeting the president, Porfirio Díaz, he set off with a team of scientists for the Sierra Madre del Norte mountains in the north-west of Mexico, to find the cave-dwelling Tarahumare Indians. Volume 2 focuses mainly on the neighbouring Huichols people, their daily life, and their religious practices, including shamanism.
Études et leçons sur la Révolution Française
Authors: Aulard Alphonse
Published: February 2012

Alphonse Aulard (1849–1928) was the first French historian to use nineteenth-century historicist methods in the study of the French Revolution. Pioneered by German historians such as Leopold van Ranke, this approach emphasised empiricism, objectivity and the scientific pursuit of facts, rather than the philosophical and literary concerns that had guided earlier scholars. Aulard's commitment to archival investigation is evidenced by the many edited collections of primary sources that appear in his extensive publication record. In these eight volumes of papers analysing the French Revolution (published 1893–1921), Aulard sought to apply the principles of historicism to reveal the truth. The work draws on earlier journal articles and lectures which Aulard delivered as Professor of the History of the French Revolution at the Sorbonne, a post he had held since 1885. Volume 1 (1893) focuses on the final year of the French monarchy, the dawn of the Republic, and the Terror.
Mathematical Methods for the Physical Sciences
Authors: Riley K. F.
Published: February 2012

Many students of physical and applied science and of engineering find difficulty in copying with the mathematics necessary for the quantitative manipulation of the physical concepts they are atudying in their main course. This book is designed to help first and second year under-graduates at universities and polytechnics, as well as technical college students, to find their feet in the important mathematical methods they will need. Throughout the text the physical relevance of the mathematics is constantly stressed and, where it is helpful, use has been made of pictorial mathematics and qualitative verbal descriptions instead of over-compact mathematical symbolism. Topics are presented in three stages: a qualitative introduction, a more formal presentation and an explicit check or worked example. There are many exercises included in the text which are aimed at testing a student's understanding and building his confidence progressively throughout each piece of work.
The three-dimensional structure of momentum transfer in turbulent channels
Authors: Lozano-Durán Adrián , Flores Oscar , Jiménez Javier
Published: February 2012

The quadrant analysis of the intense tangential Reynolds stress in plane turbulent channels is generalized to three-dimensional structures (Qs), with special emphasis on the logarithmic and outer layers. Wall-detached Qs are background stress fluctuations. They are small and isotropically oriented, and their contributions to the mean stress cancel. Wall-attached Qs are larger, and carry most of the mean Reynolds stresses. They form a family of roughly self-similar objects that become increasingly complex away from the wall, resembling the vortex clusters in del Álamo et al. (J. Fluid Mech., vol. 561, 2006, pp. 329–358). Individual Qs have fractal dimensions of the order of $D= 2$, slightly fuller than the clusters. They can be described as ‘sponges of flakes’, while vortex clusters are ‘sponges of strings’. The number of attached Qs decays away from the wall, but the fraction of the stress that they carry is independent of their sizes. A substantial fraction of the stress resides in a few large objects extending beyond the centreline, reminiscent of the very large structures of several authors. The predominant logarithmic-layer structure is a side-by-side pair of a sweep (Q4) and an ejection (Q2), with an associated cluster, and shares dimensions and stresses with the conjectured attached eddies of Townsend (J. Fluid Mech., vol. 11, 1961, pp. 97–120). Those attached eddies tend to be aligned streamwise from each other, located near the side walls between the low- and high-velocity large-scale streaks, but that organization does not extend far enough to explain the very long structures in the centre of the channel.
Inviscid instability of a stably stratified compressible boundary layer on an inclined surface
Authors: Candelier Julien , Le Dizès Stéphane , Millet Christophe
Published: February 2012

The three-dimensional stability of an inflection-free boundary layer flow of length scale$L$and maximum velocity${U}_{0} $in a stably stratified and compressible fluid of constant Brunt–Väisälä frequency$N$, sound speed${c}_{s} $and stratification length$H$is examined in an inviscid framework. The shear plane of the boundary layer is assumed to be inclined at an angle$\theta $with respect to the vertical direction of stratification. The stability analysis is performed using both numerical and theoretical methods for all the values of$\theta $and Froude number$F= {U}_{0} / (LN)$. When non-Boussinesq and compressible effects are negligible ($L/ H\ll 1$and${U}_{0} / {c}_{s} \ll 1$), the boundary layer flow is found to be unstable for any$F$as soon as$\theta \not = 0$. Compressible and non-Boussinesq effects are considered in the strongly stratified limit: they are shown to have no influence on the stability properties of an inclined boundary layer (when$F/ \sin \theta \ll 1$). In this limit, the instability is associated with the emission of internal-acoustic waves.
Long-Term Effects of a Financial Crisis: Evidence from Cash Holdings of East Asian Firms
Authors: Song Kyojik (Roy) , Lee Youngjoo
Published: February 2012

We investigate the long-term effect of the Asian financial crisis on corporate cash holdings in 8 East Asian countries. The Asian firms build up cash holdings by decreasing investment activities after the crisis. We find that the increase in cash holdings is not explained by changes in firm characteristics but by changes in the firms’ demand function for cash, which indicates that the crisis has systematically changed the firms’ cash-holding policies. Specifically, the firms’ increased sensitivity to cash flow volatility is one of the main factors explaining the higher level of their cash holdings in the postcrisis period.
Benign paroxysmal positional vertigo of the posterior semicircular canal: efficacy of Santiago treatment protocol, long-term follow up and analysis of recurrence
Authors: Soto-Varela A , Rossi-Izquierdo M , Martínez-Capoccioni G , Labella-Caballero T , Santos-Pérez S
Published: February 2012

Objectives:

To evaluate the efficacy of the Santiago treatment protocol for benign paroxysmal positional vertigo of the posterior semicircular canal, to analyse recurrence and to establish prognostic factors.

Material and methods:

Four hundred and twelve patients with unilateral benign paroxysmal positional vertigo of the posterior semicircular canal were treated with the Semont manoeuvre and, if symptoms did not resolve, successive application of three Epley manoeuvres plus Brandt–Daroff exercises.

Results:

Symptoms resolved in 404 patients (98.1 per cent); a single Semont manoeuvre was sufficient in 334 (81.2 per cent). Aetiology had no impact on resolution of symptoms or number of manoeuvres required. The estimated likelihood of recurrence was 14 per cent in the first year and 27 per cent after 10 years. The only factor indicating a worse prognosis was recurrence.

Conclusion:

In unilateral benign paroxysmal positional vertigo of the posterior semicircular canal, the above treatment protocol cured 98 per cent of patients. More than half of recurrences occurred in the first year. None of the analysed factors increased the likelihood of recurrence.
Guiding of a laser beam in collisional magnetoplasma channel
Authors: SINGH ARVINDER , SINGH NAVPREET
Published: February 2012

Laser guiding through an axially non-uniform collisional magnetoplasma channel formed by ionizing laser prepulse has been investigated. Self-defocusing of the ionizing prepulse leads to an axial non-uniform plasma channel. Due to the propagation of second laser beam through such preformed plasma channel, non-uniform heating of electrons takes place on account of non-uniform intensity distribution of laser beam. Non-uniform heating diffuses the electrons away from the axis and thereby enhances the plasma channel. Due to the competition between diffraction and refraction phenomenon through such an axial non-uniform collisional magnetoplasma channel, there is a periodic beam width variation with the distance of propagation. Second order ordinary differential equations for the beam width parameter of prepulse and the guided beam have been set up using the moment theory approach. Effect of axial non-uniformity, intensity of guided beam and magnetic field has been seen on the propagation of the second guided beam in the plasma channel.
Effect of suspended sediment on fertilization success in the scleractinian coral Pectinia lactuca
Authors: Erftemeijer Paul L.A. , Hagedorn Mary , Laterveer Michael , Craggs Jamie , Guest James R.
Published: February 2012

The effect of increased levels of suspended sediment on fertilization success in the scleractinian coral Pectinia lactuca was investigated in a laboratory experiment following a mass coral spawning event on reefs off Singapore. Egg–sperm bundles were collected from tank-spawned coral colonies collected from the field several days prior to the anticipated mass spawning. Eggs and sperm from each colony were separated and distributed systematically across replicated treatments (N = 9) with three concentrations of fine suspended sediment. Spawning and embryo development in Pectinia lactuca followed a pattern similar to other scleractinian coral species. There was a significant effect of increased suspended sediment concentration on fertilization success (P < 0.05). Both high- (169 mg l−1) and medium- (43 mg l−1) suspended sediment treatments decreased fertilization success compared to controls. These results imply that increased turbidity levels (whether chronic, such as in the waters around Singapore, or short-term, caused by a dredging operation)—when coinciding with the coral spawning season—may affect the reproductive success of corals and compromise coral recruitment and recovery of degraded reefs.
MicroRNAs: Potentially important regulators for schistosome development and therapeutic targets against schistosomiasis
Authors: CHENG GUOFENG , JIN YOUXIN
Published: February 2012

MicroRNAs (miRNAs) are small, endogenous non-coding RNA molecules that regulate gene expression post-transcriptionally by targeting the 3′ untranslated region (3′ UTR) of messenger RNAs. Since the discovery of the first miRNA in Caenorhabditis elegans, important regulatory roles for miRNAs in many key biological processes including development, cell proliferation, cell differentiation and apoptosis of many organisms have been described. Hundreds of miRNAs have been identified in various multicellular organisms and many are evolutionarily conserved. Schistosomes are multi-cellular eukaryotes with a complex life-cycle that require genes to be expressed and regulated precisely. Recently, miRNAs have been identified in two major schistosome species, Schistosoma japonicum and S. mansoni. These miRNAs are likely to play critical roles in schistosome development and gene regulation. Here, we review recent studies on schistosome miRNAs and discuss the potential roles of miRNAs in schistosome development and gene regulation. We also summarize the current status for targeting miRNAs and the potential of this approach for therapy against schistosomiasis.
The activity of drug-metabolizing enzymes and the biotransformation of selected anthelmintics in the model tapeworm Hymenolepis diminuta
Authors: BÁRTÍKOVÁ HANA , VOKŘÁL IVAN , SKÁLOVÁ LENKA , KUBÍČEK VLADIMÍR , FIRBASOVÁ JANA , BRIESTENSKÝ DAVID , LAMKA JIŘÍ , SZOTÁKOVÁ BARBORA
Published: February 2012

The drug-metabolizing enzymes of some helminths can deactivate anthelmintics and therefore partially protect helminths against these drugs' toxic effect. The aim of our study was to assess the activity of the main drug-metabolizing enzymes and evaluate the metabolism of selected anthelmintics (albendazole, flubendazole, mebendazole) in the rat tapeworm Hymenolepis diminuta, a species often used as a model tapeworm. In vitro and ex vivo experiments were performed. Metabolites of the anthelmintics were detected and identified by HPLC with spectrofluorometric or mass–spectrometric detection. The enzymes of H. diminuta are able to reduce the carbonyl group of flubendazole, mebendazole and several other xenobiotics. Although the activity of a number of oxidation enzymes was determined, no oxidative metabolites of albendazole were detected. Regarding conjugation enzymes, a high activity of glutathione S-transferase was observed. A methyl derivative of reduced flubendazole was the only conjugation metabolite identified in ex vivo incubations of H. diminuta with anthelmintics. The results revealed that H. diminuta metabolized flubendazole and mebendazole, but not albendazole. The biotransformation pathways found in H. diminuta differ from those described in Moniezia expanza and suggest the interspecies differences in drug metabolism not only among classes of helminths, but even among tapeworms.
Assessment of cathepsin D and L-like proteinases of poultry red mite,Dermanyssus gallinae(De Geer), as potential vaccine antigens
Authors: BARTLEY KATHRYN , HUNTLEY JOHN F. , WRIGHT HARRY W. , NATH MINTU , NISBET ALASDAIR J.
Published: February 2012

Vaccination is a feasible strategy for controlling the haematophagous poultry red miteDermanyssus gallinae. A cDNA library enriched for genes upregulated after feeding was created to identify potential vaccine antigens. From this library, a gene (Dg-CatD-1) encoding a 383 amino acid protein (Dg-CatD-1) with homology to cathepsin D lysosomal aspartyl proteinases was identified as a potential vaccine candidate. A second gene (Dg-CatL-1) encoding a 341 amino acid protein (Dg-CatL-1) with homology to cathepsin L cysteine proteinases was also selected for further study. IgY obtained from naturally infested hens failed to detectDg-CatD-1 suggesting that it is a concealed antigen. Conversely,Dg-CatL-1 was detected by IgY derived from natural-infestation, indicating that infested hens are exposed toDg-CatL-1. Mortality rates 120 h after mites had been fed anti-Dg-CatD-1 were significantly higher than those fed control IgY (PF<0·01). In a survival analysis, fitting a proportional hazards model to the time of death of mites, anti-Dg-CatD-1 and anti-Dg-CatL-1 IgY had 4·42 and 2·13 times higher risks of dying compared with controls (PF<0·05).Dg-CatD-1 and L-1 both have potential as vaccine antigens as part of a multi-component vaccine and have the potential to be improved as vaccine antigens using alternative expression systems.
Serine protease inhibitors of parasitic helminths
Authors: MOLEHIN ADEBAYO J. , GOBERT GEOFFREY N. , McMANUS DONALD P.
Published: February 2012

Serine protease inhibitors (serpins) are a superfamily of structurally conserved proteins that inhibit serine proteases and play key physiological roles in numerous biological systems such as blood coagulation, complement activation and inflammation. A number of serpins have now been identified in parasitic helminths with putative involvement in immune regulation and in parasite survival through interference with the host immune response. This review describes the serpins and smapins (small serine protease inhibitors) that have been identified inAscarisspp.,Brugia malayi, Ancylostoma caninum Onchocerca volvulus, Haemonchus contortus, Trichinella spiralis, Trichostrongylus vitrinus, Anisakis simplex, Trichuris suis, Schistosomaspp.,Clonorchis sinensis, Paragonimus westermaniandEchinococcusspp. and discusses their possible biological functions, including roles in host-parasite interplay and their evolutionary relationships.
Hausdorff dimension for fractals invariant under multiplicative integers
Authors: KENYON RICHARD , PERES YUVAL , SOLOMYAK BORIS
Published: February 2012

We consider subsets of the (symbolic) sequence space that are invariant under the action of the semigroup of multiplicative integers. A representative example is the collection of all 0–1 sequences (xk) such thatxkx2k=0 for allk. We compute the Hausdorff and Minkowski dimensions of these sets and show that they are typically different. The proof proceeds via a variational principle for multiplicative subshifts.
Intrinsic properties and functional circuitry of the AII amacrine cell
Authors: DEMB JONATHAN B. , SINGER JOSHUA H.
Published: February 2012

Amacrine cells represent the most diverse class of retinal neuron, comprising dozens of distinct cell types. Each type exhibits a unique morphology and generates specific visual computations through its synapses with a subset of excitatory interneurons (bipolar cells), other amacrine cells, and output neurons (ganglion cells). Here, we review the intrinsic and network properties that underlie the function of the most common amacrine cell in the mammalian retina, the AII amacrine cell. The AII connects rod and cone photoreceptor pathways, forming an essential link in the circuit for rod-mediated (scotopic) vision. As such, the AII has become known as the rod–amacrine cell. We, however, now understand that AII function extends to cone-mediated (photopic) vision, and AII function in scotopic and photopic conditions utilizes the same underlying circuit: AIIs are electrically coupled to each other and to the terminals of some types of ON cone bipolar cells. The direction of signal flow, however, varies with illumination. Under photopic conditions, the AII network constitutes a crossover inhibition pathway that allows ON signals to inhibit OFF ganglion cells and contributes to motion sensitivity in certain ganglion cell types. We discuss how the AII’s combination of intrinsic and network properties accounts for its unique role in visual processing.
The role of starburst amacrine cells in visual signal processing
Authors: TAYLOR W.R. , SMITH R.G.
Published: February 2012

Starburst amacrine cells (SBACs) within the adult mammalian retina provide the critical inhibition that underlies the receptive field properties of direction-selective ganglion cells (DSGCs). The SBACs generate direction-selective output of GABA that differentially inhibits the DSGCs. We review the biophysical mechanisms that produce directional GABA release from SBACs and test a network model that predicts the effects of reciprocal inhibition between adjacent SBACs. The results of the model simulations suggest that reciprocal inhibitory connections between closely spaced SBACs should be spatially selective, while connections between more widely spaced cells could be indiscriminate. SBACs were initially identified as cholinergic neurons and were subsequently shown to contain release both acetylcholine and GABA. While the role of the GABAergic transmission is well established, the role of the cholinergic transmission remains unclear.
Involvement of G protein and purines inRhinella arenarumoocyte maturation
Authors: Zelarayán L.I. , Ajmat M.T. , Bonilla F. , Bühler M.I.
Published: February 2012

We investigated the participation of Gαiprotein and of intracellular cAMP levels on spontaneous and progesterone-mediated maturation inRhinella arenarumfully grown follicles and denuded oocytes.

Although progesterone is the established maturation inducer in amphibians,Rhinella arenarumoocytes obtained during the reproductive period (competent oocytes) resume meiosis with no need for an exogenous hormonal stimulus if deprived of their enveloping follicular cells, a phenomenon called spontaneous maturation. In amphibian oocytes, numerous signalling mechanisms have been involved in the rapid, non-genomic, membrane effects of progesterone, but most of these are not fully understood.

The data presented here demonstrate that activation of the Gαiprotein by Mas-7 induced maturation in non-competent oocytes and also an increase in GVBD (germinal vesicle breakdown) in competent oocytes. Similar results were obtained with intact follicles independent of the season. The activation of adenylyl cyclase (AC) by forskolin seems to inhibit both spontaneous and progesterone-induced GVBD. In addition, the high intracellular levels of cAMP caused by activation of AC by forskolin treatment or addition of db-cAMP inhibited maturation that had been induced by Mas-7 and in a dose-dependent manner. Treatment with H-89, a protein kinase A (PKA) inhibitor, was able to trigger GVBD in a dose-dependent manner in non-competent oocytes and increased the percentages of GVBD in oocytes competent to mature spontaneously. The results obtained with whole follicles and denuded oocytes were similar, which suggested that effects on AC and PKA were not mediated by follicle cells. The fact that Mas-7 was able to induce maturation in non-competent oocytes in a similar manner to progesterone and to increase spontaneous maturation suggests that Gαiactivation could be an important step in meiosis resumption. Thus, the decrease in cAMP as a result of the regulation of the G proteins on AC and the inactivation of PKA by H-89 could contribute to the activation of MPF (maturation promoting factor) and induce maturation of the oocytes ofRhinella arenarum.
Social Banking
Authors: Joshi Deepali Pant
Published: February 2012

Social Banking: Promise, Performance and Potential provides an overview of the Indian banking scenario from both a historical and a theoretical perspective. It discusses the development of Social Banking, its working and its relevance for the present and the future. The book presents the contribution of banking institutions in promoting savings and investments and extending the reach of banking services.The author argues the case for large-scale Social Banking and microfinance for the alleviation of poverty. She also provides an extensive analysis of the remarkable traits that have made Social Banking a success in India and enabled the Indian banking system to reach millions of low-income savers and borrowers. It clearly demonstrates the tremendous potential embedded in well-designed institutional interventions.
Name Reactions in Organic Synthesis
Authors: Parikh Arun , Parikh Hansa , Parikh Khyati
Published: February 2012

The book focuses on main aspects of chemical reaction, i.e. principle, mechanism and applications of synthetic utility. The content is explained in an easy and simple language. It will be a good source of information for fundamental knowledge of organic synthesis to students at undergraduate level as well as industrial chemist.
On recent seismic tomography for the western United States
Authors: Becker T. W.
Published: February 2012

In recent years, a number of relatively high resolution seismic tomography models for the uppermost mantle underneath the western United States have been published, and vigorous debate has ensued about their tectonic interpretation. I present a straightforward, yet quantitative, comparison between models in order to help establish a framework for geodynamic interpretation, and to help judge the role of tomographic theory vs. data selection. Mapped S and P wave anomalies are found to be remarkably consistent between models, which implies that seismologists are beginning to narrow down the structure underneath active continental margins to scales of ∼200 km. Large discrepancies between published anomaly amplitudes exist, however, and the models on the high end of the spectrum raise questions as to how they are to be interpreted in terms of temperature, composition, and melting.
The true fluence distribution of terrestrial gamma flashes at satellite altitude
Authors: Østgaard N. , Gjesteland T. , Hansen R. S. , Collier A. B. , Carlson B.
Published: February 2012

In this paper we use the fluence distributions observed by two different instruments, RHESSI and Fermi GBM, corrected for the effects of their different orbits, combined with their different daily TGF detection rates and their relative sensitivities to make an estimate of the true fluence distribution of TGFs as measured at satellite altitudes. The estimate is then used to calculate the dead‐time loss for an average TGF measured by RHESSI. An independent estimate of RHESSI dead‐time loss and true fluence distribution is obtained from a Monte Carlo (MC) simulation in order to evaluate the consistency of our results. The two methods give RHESSI dead‐time losses of 24–26% for average fluence of 33–35 counts. Assuming a sharp cut‐off the true TGF fluence distribution is found to follow a power law with λ = 2.3 ± 0.2 down to ∼5/600 of the detection threshold of RHESSI. This corresponds to a lowest number of electrons produced in a TGF of ∼1014 and a global production rate within ±38° latitude of 50000 TGFs/day or about 35 TGFs every minute, which is 2% of all IC lightning. If a more realistic distribution with a roll‐off below 1/3 (or higher) of the RHESSI lower detection threshold with a true distribution with λ ≤ 1.7 that corresponds to a source distribution with λ ≤ 1.3 is considered, we can not rule out that all discharges produce TGFs. In that case the lowest number of total electrons produced in a TGF is ∼1012.
Evolution of permeability in heterogeneous granular aggregates during chemical compaction: Granular mechanics models
Authors: Zheng Baisheng , Elsworth Derek
Published: February 2012

We develop a granular mechanics model to represent the process of chemical compaction within granular media. This model represents the serial processes of stress‐enhanced dissolution, mass diffusion along the fluid film separating grain boundaries, and then mass ejection into the pore space, where it may then be either reprecipitated onto the pore wall or removed by fluid advection in an open system. This process is controlled by the evolution of intergranular effective stress and mass concentrations in the fluid either in the water film or the pore space. The evolution of intergranular stress is followed by a granular mechanics model that rigorously couples the magnitude of the grain‐grain contact stress to determine the time history of stress‐driven dissolution. Pore fluid concentration provides a feedback to intergranular dissolution, halting intergranular compaction as fluid concentrations approach aqueous saturation. Importantly, chemical feedbacks onto the mechanical system and mechanical feedbacks on the chemical system are rigorously accommodated. Compaction is halted either by the amelioration of the driving stress (through the growth of the contact area) or by the saturation of the fluid in the pore space. This model is used to explore the influence of heterogeneous assemblages of particles on the rate and ultimate magnitude of compaction and the resulting evolution of permeability. Specifically, we explore the influence of heterogeneity in granular packs by using heterogeneous distributions of particles (linear, Gaussian, or bimodal). Results indicate that porosity and permeability decrease with compaction. Small particles dominate this dissolution‐mediated process and accelerate compaction; this is true both for homogeneous distributions of small particles and for coarser aggregates containing a fraction of smaller particles. Overall, compaction is also greater for finer aggregates resulting from the larger deformation required, reaching the critical stress that will halt compaction. This feature is due to the necessary redistribution of intergranular stresses that are shed from point contacts in active chemical dissolution onto those not deforming.
Critical state soil constitutive model for methane hydrate soil
Authors: Uchida S. , Soga K. , Yamamoto K.
Published: February 2012

This paper presents a new constitutive model that simulates the mechanical behavior of methane hydrate‐bearing soil based on the concept of critical state soil mechanics, referred to as the “Methane Hydrate Critical State (MHCS) model”. Methane hydrate‐bearing soil is, under certain geological conditions, known to exhibit greater stiffness, strength and dilatancy, which are often observed in dense soils and also in bonded soils such as cemented soil and unsaturated soil. Those soils tend to show greater resistance to compressive deformation but the tendency disappears when the soil is excessively compressed or the bonds are destroyed due to shearing. The proposed model represents these features by introducing five extra model parameters to the conventional critical state model. It is found that, for an accurate prediction of ground settlement, volumetric yielding plays an important role when hydrate soil undergoes a significant change in effective stresses and hydrate saturation, which are expected during depressurization for methane gas recovery.
Sample dilation and fracture in response to high pore fluid pressure and strain rate in quartz‐rich sandstone and siltstone
Authors: French M. E. , Boutt D. F. , Goodwin L. B.
Published: February 2012

Natural hydraulic fractures (NHFs) are inferred to form where pore pressure exceeds the least compressive stress by an amount equal to the tensile strength of the rock. We improved upon an experimental protocol that meets the NHF criterion within cylindrical samples with the most tensile effective stress parallel to the sample axis. The effective tensile stresses achieved during these experiments ranged from 17–47 MPa. The pore fluids used had higher viscosities than water and the axial strain rate was rapid (∼10−3s−1) to delay dissipation of fluid pressure by flow. Four experiments on St. Peter Sandstone samples and two on an Abo Formation siltstone sample were performed under these conditions and under drained conditions. None of the drained experiments resulted in failure, but all of the sandstone and one of the siltstone samples fractured in response to elevated pore pressures. Consistent with field and theoretical studies, mechanical heterogeneity was a first order control on fracture location. In the absence of mesoscopic heterogeneity, fracture location coincided with the maximum pore pressure. Samples responded to elevated pore pressures and differential stresses by dilating, the magnitude of which was sufficient to achieve atmospheric pore pressure. Samples failed 2 to 250 s after experiencing the greatest pore pressures, when the effective stresses were no longer tensile. Thus, the high pore pressures and effective tensile stresses experienced early in the experiments were sufficient to fracture the rocks, even though they were not sustained until failure. These results provide insight into processes of fluid‐driven fracture formation.
Estimates of stress and strain rate in mylonites based on the boundary between the fields of grain‐size sensitive and insensitive creep
Authors: Okudaira Takamoto , Shigematsu Norio
Published: February 2012

Microstructural analyses of mylonites next to the Median Tectonic Line (MTL), SW Japan, reveal a transition in the dominant deformation mechanism of quartz from grain‐size‐insensitive dislocation creep to grain‐size‐sensitive grain‐boundary sliding (GBS). The transition occurred under greenschist‐facies conditions (∼300–400°C) during grain‐size reduction by dynamic recrystallization. The stereologically corrected grain size for the transition is approximately 4.3 μm. At the boundary between the fields of dislocation creep and GBS, as calculated from creep constitutive relations, the differential stress and strain rate for this corrected grain size are estimated to be ∼280 MPa and 1.2 × 10−11 s−1 for 300°C, and ∼110 MPa and 1.0 × 10−10 s−1 for 400°C. The strain rates estimated for the mylonites next to the MTL are much higher than those estimated for the surrounding metamorphic rocks (∼10−14 s−1), and the displacement rates calculated based on the thickness of high‐strain mylonites and their strain rates are comparable with the average slip rates of the most active intraplate faults in Japan. These inferences suggest that the high‐strain mylonite zones next to the MTL are the exhumed downward extension of a seismogenic fault in the ductile region. The zones were highly localized (<10 m) and experienced very high strain rates (10−11 to 10−10 s−1).
Shelf‐basin exchange times of Arctic surface waters estimated from 228Th/228Ra disequilibrium
Authors: Rutgers van der Loeff M. , Cai P. , Stimac I. , Bauch D. , Hanfland C. , Roeske T. , Moran S. B.
Published: February 2012

The transpolar drift is strongly enriched in 228Ra accumulated on the wide Arctic shelves with subsequent rapid offshore transport. We present new data of Polarstern expeditions to the central Arctic and to the Kara and Laptev seas. Because 226Ra activities in Pacific waters are 30% higher than in Atlantic waters, we correct 226Ra for the Pacific admixture when normalizing 228Ra with 226Ra. The use of 228Ra decay as age marker critically depends on the constancy in space and time of the source activity, a condition that has not yet adequately been tested. While 228Ra decays during transit over the central basin, ingrowth of 228Th could provide an alternative age marker. The high 228Th/228Ra activity ratio (AR = 0.8–1.0) in the central basins is incompatible with a mixing model based on horizontal eddy diffusion. An advective model predicts that 228Th grows to an equilibrium AR, the value of which depends on the scavenging regime. The low AR over the Lomonosov Ridge (AR = 0.5) can be due to either rapid transport (minimum age without scavenging 1.1 year) or enhanced scavenging. Suspended particulate matter load (derived from beam transmission and particulate 234Th) and total 234Th depletion data show that scavenging, although extremely low in the central Arctic, is enhanced over the Lomonosov Ridge, making an age of 3 years more likely. The combined data of 228Ra decay and 228Th ingrowth confirm the existence of a recirculating gyre in the surface water of the eastern Eurasian Basin with a river water residence time of at least 3 years.
Classification of aerosol radiative properties during African desert dust intrusions over southeastern Spain by sector origins and cluster analysis
Authors: Valenzuela A. , Olmo F. J. , Lyamani H. , Antón M. , Quirantes A. , Alados‐Arboledas L.
Published: February 2012

The main goal of this study is to analyze the dependence of columnar aerosol optical and microphysical properties on source region and transport pathways during desert dust intrusions over Granada (Spain) from January 2005 to December 2010. Columnar aerosol properties have been derived from a non‐spherical inversion code using the solar extinction measurements and sky radiances in the principal plane. Two classification methods of the African air masses ending at the study location were used by means of the HYSPLIT back‐trajectories analysis. The first one, based on desert dust origin sources, discriminated the optical properties only for sector B (corresponding to western Sahara, northwest Mauritania and southwest Algeria). The particles present marked absorbing properties (low value of single scattering albedo at all wavelengths) during the desert dust events when the air masses were transported from sector A (north Morocco, northwest Algeria). This result may be related to the mixing of desert dust with anthropogenic pollutants from North African industrial areas in addition to the mixing with local anthropogenic aerosol and pollutants transported from European and Mediterranean areas. The second classification method was based on a statistics technique called cluster classification which allows grouping the air masses back trajectories with similar speed and direction of the trajectory. This method showed slight differences in the optical properties between the several transport pathways of air masses. High values of the aerosol optical depth and low mean values of the Angström parameter were associated with longer transport pathways over desert dust sources and slowly moving air masses. Both classification methods showed that the fine mode was mixed with coarse mode, being the fine mode fraction smaller than 55%.
Advances in the simulation and automated measurement of well‐sorted granular material: 2. Direct measures of particle properties
Authors: Buscombe D. , Rubin D. M.
Published: February 2012

In this, the second of a pair of papers on the structure of well‐sorted natural granular material (sediment), new methods are described for automated measurements from images of sediment, of: 1) particle‐size standard deviation (arithmetic sorting) with and without apparent void fraction; and 2) mean particle size in material with void fraction. A variety of simulations of granular material are used for testing purposes, in addition to images of natural sediment. Simulations are also used to establish that the effects on automated particle sizing of grains visible through the interstices of the grains at the very surface of a granular material continue to a depth of approximately 4 grain diameters and that this is independent of mean particle size. Ensemble root‐mean squared error between observed and estimated arithmetic sorting coefficients for 262 images of natural silts, sands and gravels (drawn from 8 populations) is 31%, which reduces to 27% if adjusted for bias (slope correction between observed and estimated values). These methods allow non‐intrusive and fully automated measurements of surfaces of unconsolidated granular material. With no tunable parameters or empirically derived coefficients, they should be broadly universal in appropriate applications. However, empirical corrections may need to be applied for the most accurate results. Finally, analytical formulas are derived for the one‐step pore‐particle transition probability matrix, estimated from the image's autocorrelogram, from which void fraction of a section of granular material can be estimated directly. This model gives excellent predictions of bulk void fraction yet imperfect predictions of pore‐particle transitions.
Willingness to Pay for Obesity Pharmacotherapy
Authors: Doyle Scott , Lloyd Andrew , Birt Julie , Curtis Bradley , Ali Shehzad , Godbey Kecia , Sierra‐Johnson Justo , Halford Jason C.G.
Published: February 2012

Several treatments for obesity have received regulatory approval, but health insurers and other payers typically refuse to support access to them. Thus, patients are left to bear significant out‐of‐pocket costs for obesity pharmacotherapy. This study aimed to assess preferences and willingness to pay (WTP) for obesity medications among people seeking weight loss in the United States and United Kingdom. An online survey was developed based on literature review, clinician interviews, and profiles of available therapies. Participants indicated their preference for hypothetical treatments which varied by seven attributes: percentage of weight loss, long‐term health risk reduction, time to noticeable weight loss, delivery mode, side effects, lifestyle modification, and cost; 502 obese participants completed the survey (mean BMI 37.12 kg/m2 (±4.63); 73.5% female; 47.7 (±12.9) years of age). The participants deemed weight loss of >21 kg (United Kingdom) and >28 kg (United State) as “acceptable”. All treatment attributes were important (P < 0.001) except “time to noticeable weight loss.” The survey found that percentage weight loss was the most important factor for patients and a reduction in long‐term health risk was relatively less important. Patients were willing to pay £6.51/$10.49 per month per percentage point of weight loss that a pharmacotherapy could provide. Participants also highly valued therapies that did not require substantial lifestyle modifications and were willing to pay £17.78/$30.77 more per month for a one‐pill‐per‐day treatment vs. a weekly injectable. Participants placed a high value on weight loss and avoiding changes to their lifestyle, and less value on reducing long‐term risks to health.